Ball has chosen and arranged the various modules can be selected using this characterization . Activities axis thorough Britain at the end of two solid shaft holding components. Between two points regardless of what state the dull appearance , whether it is not just a point , the precision of this configuration will not be affected , just depends on the end support configuration accuracy. In addition, if you want to Britain at the end of a ball screw linear guide pair transmission system , just to play three holes in a board , that two circular rail and ball bearing screw support bearings as a benchmark, which is the most simple to do pace . Britain at the end of this characterization, the process of the device without modulating. Processing punish square rail deal in doubt just use a punitive program guide . Because it can support the torque on complete bias , thus resulting in bearing guideways deputy in the square without the use of guide bearings . About light load , that is bearing loads and moment loads within the scope of talent , a single square rail bearings can provide guidance for the hope , but not complete the square rail goods can operate at sample Click portrayed . This guidance eliminates the appearance of the two diverging rails to hold on to the questions. However, there is still need to consider to hold on to Britain at the end of the transmission structure , square rails does not exceed the depiction and the end support across idle . Because the eccentric load moment is generated in the rail , and therefore , shall not be deemed a single rail is probably active whereabouts wide footprint (e.g. 300mm) use . Before making a decision , you should inspect rail torque rating of its torque load stiffness.
Linear guide open to doubt a meticulous . Linear guide slider left and right ends of the surface with plastic parts, equipment , please do not use the hard stuff hammering rocket , after the commissioning of the device , do not let any object speeding its impact, assuming plastic parts break , the ball will roll out , the slider will fall 2 . linear guide who lives in the factory before a lubricant , if you want to hold washing , dry point that should be first in the lives lubricants, restraint linear guide running without lubrication under 3 do not need to do if the slider is detached from the linear guide , if not unloaded , it must first be helper linear guide on the positive, on the slider remove 4 . restraint random Unpack the linear guide components , Yibi affect the accuracy and sensitivity , linear guides free to install restraint do not meet the rules of the ball
2013年8月29日星期四
Ball control card work
If, ball bearing screw in the process of acceleration and deceleration , a short play high current needs, you must be active in the planning stages of thinking equivalent thrust , depending on the actual needs , adding cease activity time . Else if the motor current is continuously pushing things matter more than the continuous current , but also dependable overheating problems . So the system in planning activities necessary when thinking about the layout of the motor heat dissipation characteristics . Lead offset preloading essentials : ( increase pitch or pitch out )
Features: on the pitch for the nut offset δ values to replace the traditional double nut preload essentials , the essentials and more practical in the light preload , the best plan in the pre- pressure dynamic load of 5% or less. Tensile preload essentials features : the use of a pre- thick tablet will arrive two nuts outside the sheets essentials preload results , this is the most common use of the ball screw essentials . Features : the thin film preload , then screw nut bolt two together , to reach the pre- pressure of the results.
Ball control fundamentally similar essentials , such acceptance pulse controlled, active control card is still sent to the drive pulse , the other situation or if the current situation is the speed (or torque or strength situation ) by the same active controller sends voltage to the drive. Difference is that control linear motor, will not need to have complicated conversion strategy , gear ratio strategy , just directly to the activities tend to consider the isolation , strategy can be, but also directly with the activities set acceleration and speed that is biased available . Individually any motor problems accompanied by fever , we must think in the planning stages of this problem , fever tension from acceleration and deceleration , if the acceleration and deceleration are maintained at the current required to drive the motor and under continuous current , there will be no tension heating problem .
Features: on the pitch for the nut offset δ values to replace the traditional double nut preload essentials , the essentials and more practical in the light preload , the best plan in the pre- pressure dynamic load of 5% or less. Tensile preload essentials features : the use of a pre- thick tablet will arrive two nuts outside the sheets essentials preload results , this is the most common use of the ball screw essentials . Features : the thin film preload , then screw nut bolt two together , to reach the pre- pressure of the results.
Ball control fundamentally similar essentials , such acceptance pulse controlled, active control card is still sent to the drive pulse , the other situation or if the current situation is the speed (or torque or strength situation ) by the same active controller sends voltage to the drive. Difference is that control linear motor, will not need to have complicated conversion strategy , gear ratio strategy , just directly to the activities tend to consider the isolation , strategy can be, but also directly with the activities set acceleration and speed that is biased available . Individually any motor problems accompanied by fever , we must think in the planning stages of this problem , fever tension from acceleration and deceleration , if the acceleration and deceleration are maintained at the current required to drive the motor and under continuous current , there will be no tension heating problem .
2013年8月27日星期二
Raw material roller press bearing damage cause analysis and maintenance recommendations
In the dry process cement production line process, the raw material has been widely used roller press, and has made considerable economic and social benefits, a significant increase of its energy-saving effect is also recognized by the majority of manufacturers to use. But in the course of its use, the bearing life is short, damage and replacement process cycle is long, costly, labor-intensive, but it restricts the normal operation of the rotary kiln.
My company put into operation by the end of 2012 the two 4500t / d clinker production line, run until June 2003, four sets of Chengdu Lijun Industrial Co., Ltd. manufactured CLF180-120 there have been varying degrees of roller presses the problem of high bearing temperatures, 7 mid-May the 2nd roll maneuver near the gear side roller bearing damage. Total running time of 2041 hours, the service life of less than three months.
First, the device pre-operational status
Roller press run early roller bearing temperature between 50-60 degrees, there is no abnormal noise, bearing grease used by the U.S. Castrol brand Molub-Alloy 777-2 ES model roller presses grease, the amount of fuel in strict accordance with equipment manufacturers Requests the Executive. Five to six months, there have been several cycles of water blockage, resulting in bearing temperature up to 70 degrees. In mid-June, and found that the lower part of the inner bearing oil outlet circulating water discharge phenomenon occurs suspected side of the bearing end cap rupture caused by cooling water, then turn off the inside of the circulating water, the new grease replenishing the oil discharged into the roller press production. In early July, roller presses the bearing temperature has been hovering around 55 degrees to 75 degrees, for various reasons during the roller press is always open to open the stop, there have been more than 24 hours continuously feeding situation. July 10 start, roller press repeatedly appear continuous feeding more than four hours on account of the temperature exceeds 75 degrees to stop jumping. July 12 greaser checking the oil discharge roller press discovered the bearing fragments. Determine the bearing roller press has been damaged. Since the roller press has been put into the roll gap deviation, pressure instability. Deviation due to the roll gap gauge, pressure gauge, the width of the roll gap and other factors frequently exceeds the limit mediation, there have been almost no more than 48 hours continuously feeding situation.
Second, the disintegration of the investigation bearing damage
After the demolition of the roller press gearbox bearing cap open and found that there is a rift bearing outside diameter, a broken ball bearings, inner and outer diameter with five out of crack, the bearing inner and outer raceway badly worn bearing retainer wear . Bearing cap surrounded by circulating water cooling on both sides have two brass compression fracture phenomena, round copper tubes are flattened, leading to fracture, width of about 100mm. Check the other side of the roll maneuver roller bearings, intact, the bearing clearance of 0.75mm, within the normal range.
Third, bearing damage cause analysis and improvement
1 First, bearing life is too short not to troubleshoot and manufacturer of quality bearing assembly itself, but should also work with bearing operating conditions in harsh environments and have a great relationship.
2. Bearing thermal design flaws. Such a large bearing operating process will produce a lot of frictional heat, so that both sides of the bearing cap manufacturer designed circulating path, the heat generated by the bearing grease and the case conduction through the cooling copper tube absorbs heat water circulating outflow apparatus body, lower bearing temperatures. But it cooled copper mounting position is unreasonable, bearing swing too easy to squeeze into the brass, brass deformation caused by blockage, fracture, loss of cooling effect. To avoid copper tube is extruded, only increase the gap between the copper and the bearing, to ensure a greater swing bearing free space, which requires manufacturers to redesign, production bearing cap or another design a cooling device.
3 brass water lead to rupture of the rear bearing lubrication failure, it could be this short bearing life is an important factor. Equipment inspection work found during the inspections bearing lower discharge port has water leakage, immediately made a report, but this is not possible in the cooling copper pipe break after the first time discovered. Since the bearing inner brass cap by squeezing fracture, circulating water entering the bearing, destroyed the environment lubrication, the bearing balls and the raceway serious friction generates a lot of heat, bearing balls and the diameter of each component such damage.
4 brass frequent clogging cooling and design too small, poor cooling effect also affect bearing life. Cooled copper diameter is too small, the circulating water and debris clog adhesion brass scale deposition in the roller press often occurs during operation bearing high temperature, inlet and outlet brass examination revealed multiple blockage, affecting the cooling effect, the final installed at the inlet Y-strainer before easing clogging.
5 roller presses the material into the inadequate control of particle size, diameter 200mm super chunk too, long nip large deviations, corrective frequently lead to bearing overload and shorten the service life. Initial production mining crushing, crushing machine safety door is not well controlled, resulting in more than 150mm above the individual particle size of limestone blocks into the next process, clogging the feed opening roller press, leading to uneven feeding, causing the roll gap large deviations, and even lead roll sewing too large equipment mediation. Granularity than 100mm rigid material frequently enters roller presses, roller presses squeeze in an instant when all the large reaction force bearing on the bearing itself, the life of the bearing caused a fundamental impact. Improved granularity of limestone, sandstone and clay crusher materials and faulty phase continued up to more than two months, no broken, large water through the bypass feed materials into the roller press feeding system, more than 250mm above the chunk size is almost Each class appears stuck roll gap, resulting in the roll gap width gauge mediation. This is the roller press operation there have been no more than six months more than 48 hours continuously feeding the root cause.
6 There is no steady flow positions periodically removed materials, excluding enrichment metal, so that the device frequently overloaded mediation affect bearing life. Material into the roller press is impossible to avoid the presence of metal objects and accumulation roller presses the original width of the roll gap of about 20mm, 70mm roll gap will exceed the overload relief, less than 50mm metal objects will only increase the roll surface wear, greater than 50mm size metal objects or materials into the roller press is too large, it will cause the rollers instantly generate excessive impact force, resulting in the roll gap than 70mm, the pressure exceeds 15MPa, exceeds the bearing load limits, the control system will suddenly roller press release pressure or mediation. Especially metal roller presses will cycle loop in the roller press greatest harm. So they requested that must be periodically clearing, clearing accumulated in the roller press metal objects within the system, reduce or avoid damage to equipment, particularly bearing.
7 hidden when the hydraulic system is now hidden, long-term bias is serious roll gap. As the hydraulic system problems, often lower than the pressure roller presses the side of the working pressure, both sides of the roll gap large deviation hydraulic pump long-term frequent correction, resulting in roller presses the bearing operating conditions poor, heavy load, the service life is reduced.
Fourth, the late running Precautions
Roller press bearing life is short, equipment failure rate is the current cement industry a common problem, through analysis of the above reasons, the production process management is a top priority, as long as control the granularity of the material into the roller press, regularly scheduled clearance, reducing metal roller presses against the probability of overload damage to the bearings, excluding hydraulic system problems, eliminating the long-term bias roll gap phenomenon, problem solving partial cutting, take care of the bearing uniform force. As long as the above points, improving the operating environment of the equipment, the equipment can operate normally, to extend the life of each part, in order to improve the operation rate.
My company put into operation by the end of 2012 the two 4500t / d clinker production line, run until June 2003, four sets of Chengdu Lijun Industrial Co., Ltd. manufactured CLF180-120 there have been varying degrees of roller presses the problem of high bearing temperatures, 7 mid-May the 2nd roll maneuver near the gear side roller bearing damage. Total running time of 2041 hours, the service life of less than three months.
First, the device pre-operational status
Roller press run early roller bearing temperature between 50-60 degrees, there is no abnormal noise, bearing grease used by the U.S. Castrol brand Molub-Alloy 777-2 ES model roller presses grease, the amount of fuel in strict accordance with equipment manufacturers Requests the Executive. Five to six months, there have been several cycles of water blockage, resulting in bearing temperature up to 70 degrees. In mid-June, and found that the lower part of the inner bearing oil outlet circulating water discharge phenomenon occurs suspected side of the bearing end cap rupture caused by cooling water, then turn off the inside of the circulating water, the new grease replenishing the oil discharged into the roller press production. In early July, roller presses the bearing temperature has been hovering around 55 degrees to 75 degrees, for various reasons during the roller press is always open to open the stop, there have been more than 24 hours continuously feeding situation. July 10 start, roller press repeatedly appear continuous feeding more than four hours on account of the temperature exceeds 75 degrees to stop jumping. July 12 greaser checking the oil discharge roller press discovered the bearing fragments. Determine the bearing roller press has been damaged. Since the roller press has been put into the roll gap deviation, pressure instability. Deviation due to the roll gap gauge, pressure gauge, the width of the roll gap and other factors frequently exceeds the limit mediation, there have been almost no more than 48 hours continuously feeding situation.
Second, the disintegration of the investigation bearing damage
After the demolition of the roller press gearbox bearing cap open and found that there is a rift bearing outside diameter, a broken ball bearings, inner and outer diameter with five out of crack, the bearing inner and outer raceway badly worn bearing retainer wear . Bearing cap surrounded by circulating water cooling on both sides have two brass compression fracture phenomena, round copper tubes are flattened, leading to fracture, width of about 100mm. Check the other side of the roll maneuver roller bearings, intact, the bearing clearance of 0.75mm, within the normal range.
Third, bearing damage cause analysis and improvement
1 First, bearing life is too short not to troubleshoot and manufacturer of quality bearing assembly itself, but should also work with bearing operating conditions in harsh environments and have a great relationship.
2. Bearing thermal design flaws. Such a large bearing operating process will produce a lot of frictional heat, so that both sides of the bearing cap manufacturer designed circulating path, the heat generated by the bearing grease and the case conduction through the cooling copper tube absorbs heat water circulating outflow apparatus body, lower bearing temperatures. But it cooled copper mounting position is unreasonable, bearing swing too easy to squeeze into the brass, brass deformation caused by blockage, fracture, loss of cooling effect. To avoid copper tube is extruded, only increase the gap between the copper and the bearing, to ensure a greater swing bearing free space, which requires manufacturers to redesign, production bearing cap or another design a cooling device.
3 brass water lead to rupture of the rear bearing lubrication failure, it could be this short bearing life is an important factor. Equipment inspection work found during the inspections bearing lower discharge port has water leakage, immediately made a report, but this is not possible in the cooling copper pipe break after the first time discovered. Since the bearing inner brass cap by squeezing fracture, circulating water entering the bearing, destroyed the environment lubrication, the bearing balls and the raceway serious friction generates a lot of heat, bearing balls and the diameter of each component such damage.
4 brass frequent clogging cooling and design too small, poor cooling effect also affect bearing life. Cooled copper diameter is too small, the circulating water and debris clog adhesion brass scale deposition in the roller press often occurs during operation bearing high temperature, inlet and outlet brass examination revealed multiple blockage, affecting the cooling effect, the final installed at the inlet Y-strainer before easing clogging.
5 roller presses the material into the inadequate control of particle size, diameter 200mm super chunk too, long nip large deviations, corrective frequently lead to bearing overload and shorten the service life. Initial production mining crushing, crushing machine safety door is not well controlled, resulting in more than 150mm above the individual particle size of limestone blocks into the next process, clogging the feed opening roller press, leading to uneven feeding, causing the roll gap large deviations, and even lead roll sewing too large equipment mediation. Granularity than 100mm rigid material frequently enters roller presses, roller presses squeeze in an instant when all the large reaction force bearing on the bearing itself, the life of the bearing caused a fundamental impact. Improved granularity of limestone, sandstone and clay crusher materials and faulty phase continued up to more than two months, no broken, large water through the bypass feed materials into the roller press feeding system, more than 250mm above the chunk size is almost Each class appears stuck roll gap, resulting in the roll gap width gauge mediation. This is the roller press operation there have been no more than six months more than 48 hours continuously feeding the root cause.
6 There is no steady flow positions periodically removed materials, excluding enrichment metal, so that the device frequently overloaded mediation affect bearing life. Material into the roller press is impossible to avoid the presence of metal objects and accumulation roller presses the original width of the roll gap of about 20mm, 70mm roll gap will exceed the overload relief, less than 50mm metal objects will only increase the roll surface wear, greater than 50mm size metal objects or materials into the roller press is too large, it will cause the rollers instantly generate excessive impact force, resulting in the roll gap than 70mm, the pressure exceeds 15MPa, exceeds the bearing load limits, the control system will suddenly roller press release pressure or mediation. Especially metal roller presses will cycle loop in the roller press greatest harm. So they requested that must be periodically clearing, clearing accumulated in the roller press metal objects within the system, reduce or avoid damage to equipment, particularly bearing.
7 hidden when the hydraulic system is now hidden, long-term bias is serious roll gap. As the hydraulic system problems, often lower than the pressure roller presses the side of the working pressure, both sides of the roll gap large deviation hydraulic pump long-term frequent correction, resulting in roller presses the bearing operating conditions poor, heavy load, the service life is reduced.
Fourth, the late running Precautions
Roller press bearing life is short, equipment failure rate is the current cement industry a common problem, through analysis of the above reasons, the production process management is a top priority, as long as control the granularity of the material into the roller press, regularly scheduled clearance, reducing metal roller presses against the probability of overload damage to the bearings, excluding hydraulic system problems, eliminating the long-term bias roll gap phenomenon, problem solving partial cutting, take care of the bearing uniform force. As long as the above points, improving the operating environment of the equipment, the equipment can operate normally, to extend the life of each part, in order to improve the operation rate.
Rolling residual magnetism technical conditions
Truck crane telescopic cylinder piston rod (pole) grinding waste-prone, according to our experience, the following measures to prevent waste.
1 piece of each point carefully measuring the amount of remaining mill
Should be based on the workpiece bending, deflection, dislocation and other data to determine whether the depth marks grinding.
(1) for grinding of not more than 0.50mm left the site operator can carefully measure the deflection, bending, dislocation, marks and other values. Leaving less than 0.20mm for grinding workpieces must consult the staff agreed before grinding.
(2) If the amount of deflection or bending amount exceeding one third of the parts to wear straightening after grinding.
(3) measuring the diameter of dislocation sites on both sides of both sides of the deflection data and the data available at the mill minimum diameter maximum value minus the yaw yaw position value, the amount of the difference is the actual grinding. Such as: dislocation at the grinding capacity of the smallest diameter 0.40mm, maximum deflection part of the deflection is 0.30mm, the actual grinding capacity equal to 0.40-0.30 = 0.10mm, grinding capacity is small, it is likely appear in the grinding burn conditions, resulting in waste.
(4) marks the site of deep, roll bearings grinding rasp the former is best to use local symmetry points (the most serious side parts) filed a two symmetrical facets, by filing off the site measured. If the measured diameter minus the diameter of marks after less than 0.20mm, should consult before grinding.
(2) properly handle grinding burns
(A) before grinding grinding according to the above requirements can be checked, if the coarse grinding sparks big, there are local burns, while after two reciprocating grinding burn site can not be eliminated, it should be carried out once the workpiece deflection values measurements. If the deflection values ??were lower than the preceding grinding limit, should be straightened. By straightening still not eliminated, must be scrapped.
(2) grinding sparks should pay attention to the changes, once burned, the workpiece Serve waste. Special minor burns, if measured yaw values ??below one-third of the amount of grinding, you can continue grinding; than one-third of which should be scrapped.
Burn causes and the wheel model, the workpiece material is also a relationship. Preventive measures are timely repair wheel, adjust the amount of feed (coarse or fine grinding, if the feed rate is too small will produce minor burns), add enough coolant and adjust the workpiece and wheel speed.
3 Carefully observe the spark
Once the grinding sparks too large to immediately retract. After all coarse grinding sparks phenomenon should not be interrupted, if the deflection off the fire area exceeds the amount of a quarter mill, to be straightened. Each wheel sparks near the ends of the workpiece gradually increased, the top should be checked whether the temperature is too high, if the top temperature is consistent with the workpiece to be tight at the top end. If the spark through bays larger, it indicates that the site of the top bracket is unreasonable, so that it temperature. Grinding sparks should not exist when the elephant stopped, if a serious fire off what should be measured yaw and grinding capacity, when the amount of deflection over a quarter mill grind it up.
4. Strictly control the quality and accuracy of processing
The spot diameter measured values ??are inconsistent, brackets and tailstock respond timely adjustments.
(1) through coarse, semi-fine grinding, the workpiece is not cylindrical tolerance. If ovality tolerance of the parts of a broken fire phenomenon, should be measured yaw value, if this value exceeds 30μm should try again after straightening mill; After several feed grinding, in total more than 50μm feed when Sparks will no longer off the fire, measured ovality should be zero; when measured ellipticity still exceeds tolerance, you should try again after grinding wheel dressing, if the ellipse is still not eliminated, the top hole should be checked for damage, research injuries ( At this point the workpiece surface showing polygonal).
(2) the surface after grinding and finishing the reasons presented Duoleng measures: If wheel has been blunt, should be trimmed; wheel if there is noticeable vibration, balance should be adjusted; head frame, motor frame vibration isolation facilities have been damaged, shall be repaired ; excessive vibration if the workpiece itself, should be properly deceleration; top too tight or too loose, it should be adjusted.
(3) If the coarse surface occurs when a large spiral, the reason is bad dresser, grinding wheel dressing time must be uniform and must not have significant single angle spark phenomenon blunt surface after grinding wheel prone to large spiral.
(4) grinding, the workpiece often appear galling, scratched and dirty coolant phenomenon. To prevent this phenomenon, the new wheel should be finishing with a wire brush a few times (pay attention to safety).
(5) When grinding the workpiece phenomenon taper, drum, saddle-shaped, both ends of a diameter larger or smaller, you should adjust the bracket, tailstock, wheel overrun and the number of workpieces at both ends of the workpiece and the grinding wheel travel time.
5 strictly controlled two top parts of the temperature
According to two top temperature changes are reasonable judgment leading tightness; generally top temperature slightly higher than the temperature of the workpiece as the standard.
(A) two leading causes of high temperatures: First, the top too tight, two center hole is top notch and the workpiece misalignment. If the top is too tight, first loosen the top, add the butter on the two center hole and then adjust the tightness of the top.
(2) If there is a top temperature is too high, then the top center hole with the workpiece misalignment.
(3) When the temperature of the top two consistent temperature of the workpiece, the workpiece two polygonal phenomenon does not occur, and more uniform spark, this time to continue the grinding. As part two phenomena appear Duoleng, you should look at the top tight, if the workpiece does not burn, you can wear them all. When the workpiece two spark uneven, they will bear about the top end.
1 piece of each point carefully measuring the amount of remaining mill
Should be based on the workpiece bending, deflection, dislocation and other data to determine whether the depth marks grinding.
(1) for grinding of not more than 0.50mm left the site operator can carefully measure the deflection, bending, dislocation, marks and other values. Leaving less than 0.20mm for grinding workpieces must consult the staff agreed before grinding.
(2) If the amount of deflection or bending amount exceeding one third of the parts to wear straightening after grinding.
(3) measuring the diameter of dislocation sites on both sides of both sides of the deflection data and the data available at the mill minimum diameter maximum value minus the yaw yaw position value, the amount of the difference is the actual grinding. Such as: dislocation at the grinding capacity of the smallest diameter 0.40mm, maximum deflection part of the deflection is 0.30mm, the actual grinding capacity equal to 0.40-0.30 = 0.10mm, grinding capacity is small, it is likely appear in the grinding burn conditions, resulting in waste.
(4) marks the site of deep, roll bearings grinding rasp the former is best to use local symmetry points (the most serious side parts) filed a two symmetrical facets, by filing off the site measured. If the measured diameter minus the diameter of marks after less than 0.20mm, should consult before grinding.
(2) properly handle grinding burns
(A) before grinding grinding according to the above requirements can be checked, if the coarse grinding sparks big, there are local burns, while after two reciprocating grinding burn site can not be eliminated, it should be carried out once the workpiece deflection values measurements. If the deflection values ??were lower than the preceding grinding limit, should be straightened. By straightening still not eliminated, must be scrapped.
(2) grinding sparks should pay attention to the changes, once burned, the workpiece Serve waste. Special minor burns, if measured yaw values ??below one-third of the amount of grinding, you can continue grinding; than one-third of which should be scrapped.
Burn causes and the wheel model, the workpiece material is also a relationship. Preventive measures are timely repair wheel, adjust the amount of feed (coarse or fine grinding, if the feed rate is too small will produce minor burns), add enough coolant and adjust the workpiece and wheel speed.
3 Carefully observe the spark
Once the grinding sparks too large to immediately retract. After all coarse grinding sparks phenomenon should not be interrupted, if the deflection off the fire area exceeds the amount of a quarter mill, to be straightened. Each wheel sparks near the ends of the workpiece gradually increased, the top should be checked whether the temperature is too high, if the top temperature is consistent with the workpiece to be tight at the top end. If the spark through bays larger, it indicates that the site of the top bracket is unreasonable, so that it temperature. Grinding sparks should not exist when the elephant stopped, if a serious fire off what should be measured yaw and grinding capacity, when the amount of deflection over a quarter mill grind it up.
4. Strictly control the quality and accuracy of processing
The spot diameter measured values ??are inconsistent, brackets and tailstock respond timely adjustments.
(1) through coarse, semi-fine grinding, the workpiece is not cylindrical tolerance. If ovality tolerance of the parts of a broken fire phenomenon, should be measured yaw value, if this value exceeds 30μm should try again after straightening mill; After several feed grinding, in total more than 50μm feed when Sparks will no longer off the fire, measured ovality should be zero; when measured ellipticity still exceeds tolerance, you should try again after grinding wheel dressing, if the ellipse is still not eliminated, the top hole should be checked for damage, research injuries ( At this point the workpiece surface showing polygonal).
(2) the surface after grinding and finishing the reasons presented Duoleng measures: If wheel has been blunt, should be trimmed; wheel if there is noticeable vibration, balance should be adjusted; head frame, motor frame vibration isolation facilities have been damaged, shall be repaired ; excessive vibration if the workpiece itself, should be properly deceleration; top too tight or too loose, it should be adjusted.
(3) If the coarse surface occurs when a large spiral, the reason is bad dresser, grinding wheel dressing time must be uniform and must not have significant single angle spark phenomenon blunt surface after grinding wheel prone to large spiral.
(4) grinding, the workpiece often appear galling, scratched and dirty coolant phenomenon. To prevent this phenomenon, the new wheel should be finishing with a wire brush a few times (pay attention to safety).
(5) When grinding the workpiece phenomenon taper, drum, saddle-shaped, both ends of a diameter larger or smaller, you should adjust the bracket, tailstock, wheel overrun and the number of workpieces at both ends of the workpiece and the grinding wheel travel time.
5 strictly controlled two top parts of the temperature
According to two top temperature changes are reasonable judgment leading tightness; generally top temperature slightly higher than the temperature of the workpiece as the standard.
(A) two leading causes of high temperatures: First, the top too tight, two center hole is top notch and the workpiece misalignment. If the top is too tight, first loosen the top, add the butter on the two center hole and then adjust the tightness of the top.
(2) If there is a top temperature is too high, then the top center hole with the workpiece misalignment.
(3) When the temperature of the top two consistent temperature of the workpiece, the workpiece two polygonal phenomenon does not occur, and more uniform spark, this time to continue the grinding. As part two phenomena appear Duoleng, you should look at the top tight, if the workpiece does not burn, you can wear them all. When the workpiece two spark uneven, they will bear about the top end.
2013年8月24日星期六
Bearing after the heat treatment quality problems often
A soft spot
Because insufficient heating and cooling is bad, improper operation and other causes hardening of the bearing surface of the part of the phenomenon known locally insufficient hardness quenching soft spots. It is the same as the surface decarburization can cause surface wear resistance and fatigue strength in serious decline.
Roller bearing parts in the quenching process due to the formation of stress cracks called quenching cracks. Cause such cracks reasons: because the quenching temperature is too high or too fast cooling, thermal stress and metal mass volume change when the stress fracture resistance than steel; work surface defects original (such as surface micro-cracks or draw marks) or steel internal defects (such as slag, severe non-metallic inclusions, white point, residual shrinkage, etc.) at a stress concentration quenching; severe surface decarburization and carbide segregation; parts after quenching and tempering insufficient or timely tempering; previous process caused by too much stress cold punching, forging folding, turning deep marks, oil, sharp edges, etc. ditch. Quenching cracks deep and slender, straight fracture, fracture surface without oxidation colors. The organization is characterized by quenching cracks no cracks on both sides of decarburization phenomenon, the obvious difference with forging cracks and material cracks. In short, resulting in quenching cracks may be due to one or more of these factors, the existence of internal stress cracks forming the main hardening. It is often in the bearing rings on the straight longitudinal cracks or ring cracking; ball bearing on the shape of the S-shaped, T-shaped or ring.
Second, due to heat
Three, overheating
Fourth, quenching cracks
Bearing parts in the heat treatment process, if it is heated in an oxidizing medium, the surface oxidation occurs to parts of the surface carbon content reduced, resulting in surface decarburization. Determination of surface decarburization depth available in metallographic examination and microhardness metallographic method. Surface decarburization depth over the last machining allowance will make parts scrapped. In the surface layer microhardness distribution curve measurement prevail, do arbitration criterion.
Five, surface decarburization
Six, heat deformation
Quenching temperature is low or poor cooling in the microstructure produced more than the standard prescribed troostite organization called due to heat tissue, which decrease in hardness, wear resistance drastically reduced, affecting bearing life.
Bearing parts during heat treatment, the presence of thermal stress and stress, this stress can be superimposed on each other, or partially offset, is complex, because it along with the heating temperature, heating rate, cooling, cooling rate, part shape and the size of the change, so the heat distortion is inevitable. Understand and grasp its variation can make the bearing part of the deformation (such as elliptical rings, rose and large size) placed controllable range, is conducive to the production of conduct. Of course, during the heat treatment the mechanical collision of parts also cause deformation, but this deformation can be used to reduce and improve operations avoided.
Port from the bearing part can be observed on the rough microstructure after hardening overheating. But to determine the exact extent of overheating must observe the microstructure. If GCr15 steel hardened tissues appear coarse acicular martensite, was quenched overheating tissue. Even cause serious overheating quenching cracks. As quenching overheated steel coarse crystals, may cause parts of the decrease in toughness, impact resistance decreased, the bearing life is reduced. Overheating tissues residual austenite increases, dimension stability decreased. Formation may be due to the quenching temperature is too high or too long causing heat insulation comprehensive overheating; also may be due to the original organization carbon ribbon severe in the two areas with the formation of carbon between the local martensite needles thick, caused by local overheating.
Several bearing the above heat treatment process recurrent problem, which directly affect the quality of the bearing, so that the production process of the bearing, should try to avoid such a situation.
Because insufficient heating and cooling is bad, improper operation and other causes hardening of the bearing surface of the part of the phenomenon known locally insufficient hardness quenching soft spots. It is the same as the surface decarburization can cause surface wear resistance and fatigue strength in serious decline.
Roller bearing parts in the quenching process due to the formation of stress cracks called quenching cracks. Cause such cracks reasons: because the quenching temperature is too high or too fast cooling, thermal stress and metal mass volume change when the stress fracture resistance than steel; work surface defects original (such as surface micro-cracks or draw marks) or steel internal defects (such as slag, severe non-metallic inclusions, white point, residual shrinkage, etc.) at a stress concentration quenching; severe surface decarburization and carbide segregation; parts after quenching and tempering insufficient or timely tempering; previous process caused by too much stress cold punching, forging folding, turning deep marks, oil, sharp edges, etc. ditch. Quenching cracks deep and slender, straight fracture, fracture surface without oxidation colors. The organization is characterized by quenching cracks no cracks on both sides of decarburization phenomenon, the obvious difference with forging cracks and material cracks. In short, resulting in quenching cracks may be due to one or more of these factors, the existence of internal stress cracks forming the main hardening. It is often in the bearing rings on the straight longitudinal cracks or ring cracking; ball bearing on the shape of the S-shaped, T-shaped or ring.
Second, due to heat
Three, overheating
Fourth, quenching cracks
Bearing parts in the heat treatment process, if it is heated in an oxidizing medium, the surface oxidation occurs to parts of the surface carbon content reduced, resulting in surface decarburization. Determination of surface decarburization depth available in metallographic examination and microhardness metallographic method. Surface decarburization depth over the last machining allowance will make parts scrapped. In the surface layer microhardness distribution curve measurement prevail, do arbitration criterion.
Five, surface decarburization
Six, heat deformation
Quenching temperature is low or poor cooling in the microstructure produced more than the standard prescribed troostite organization called due to heat tissue, which decrease in hardness, wear resistance drastically reduced, affecting bearing life.
Bearing parts during heat treatment, the presence of thermal stress and stress, this stress can be superimposed on each other, or partially offset, is complex, because it along with the heating temperature, heating rate, cooling, cooling rate, part shape and the size of the change, so the heat distortion is inevitable. Understand and grasp its variation can make the bearing part of the deformation (such as elliptical rings, rose and large size) placed controllable range, is conducive to the production of conduct. Of course, during the heat treatment the mechanical collision of parts also cause deformation, but this deformation can be used to reduce and improve operations avoided.
Port from the bearing part can be observed on the rough microstructure after hardening overheating. But to determine the exact extent of overheating must observe the microstructure. If GCr15 steel hardened tissues appear coarse acicular martensite, was quenched overheating tissue. Even cause serious overheating quenching cracks. As quenching overheated steel coarse crystals, may cause parts of the decrease in toughness, impact resistance decreased, the bearing life is reduced. Overheating tissues residual austenite increases, dimension stability decreased. Formation may be due to the quenching temperature is too high or too long causing heat insulation comprehensive overheating; also may be due to the original organization carbon ribbon severe in the two areas with the formation of carbon between the local martensite needles thick, caused by local overheating.
Several bearing the above heat treatment process recurrent problem, which directly affect the quality of the bearing, so that the production process of the bearing, should try to avoid such a situation.
Bearing grinding process and requirements
Bearing in precision grinding, the rough demanding working surface of the grinding traces are often observed with the naked eye the surface of the grinding marks are the following:
Bearing surfaces are crossed spiral traces traces happen mainly due to poor wheel of the bus straight, there is uneven phenomenon, grinding, grinding wheel and the workpiece is only partial contact bearing, when the workpiece or wheel back and forth several times after exercise , the performance will be reproduced in the workpiece and the cross-helix can be observed visually. The pitch of the helix and the workpiece table speed, the size of workpiece speed, but also with the wheel axis is not parallel to the guide lines and the table.
(A) The main reason for the formation of helix
1 Dresser bad, not chamfered corners, unused coolant to be trimmed;
2 table guide rail lubricant too much, resulting workbench floating;
3 machine precision is not good;
4 grinding pressure is too big.
(B) forming the bearing surfaces having the spiral cause
1.V shaped rail rigidity bad, when an offset grinding wheel, but wheel edge in contact with the work surface;
2 noisy wheel dressing table commutation speed is unstable, accuracy is not high, so that the edge of a grinding wheel dressing slightly less;
3. Workpiece itself rigidity;
4 wheel has broken too flaking grit and the workpiece grinding wheel under the iron plot attached to the surface, this should be a good dressing wheel with cooling water wash or scrub clean;
5 wheel dressing well, there are local projections and so on.
Surface appears scaly scaly surface reproduces the main reason is due to traces of grinding wheel cutting edge is not sharp enough, in the grinding occurs when "eating to live" phenomenon, when large vibration.
Resulting in surface appears scaly traces of the specific reasons are:
A grinding wheel surface litter and oil thing;
2 Wheel untrimmed round;
3 wheel blunt. Dressing sharp enough;
4 fastening frame is not solid diamond, diamond or diamond quality is bad not shake sharp;
5 Wheel hardness uneven.
Face nap nap surface reproduces the main reason is due to traces of coarse grains shed, grain sandwiched between the workpiece and the grinding wheel and cause.
Workpiece surface grinding was napping in the specific reasons are:
1 coarse grinding traces left behind, grinding when not worn;
2 coolant coarse grains and tiny grains filter is not clean;
3 coarse abrasive wheel just trimmed off easily when;
4 toughness validity or grinding wheel is too soft;
5 abrasive workpiece material toughness with toughness and improper.
Have a direct bearing surface waveform traces we milled workpiece cut a cross-section perpendicular axis line and zoom, you can see the surrounding approximately sinusoidal. So that the center line along the axis of rotation without translation, the track is the sine waveform around the cylinder, which is also known as a polygon. Generating direct wave because the wheel moves relative to the workpiece or the grinding wheel on the workpiece by cyclically changing pressure and vibration caused by the exigencies. This vibration may be forced vibration, it may be self-excited vibration, thus directly on the workpiece often more than one wave frequency.
Direct waveform traces generated specific reasons are:
A grinding wheel spindle gap is too large;
2 Wheel hardness is too high;
3 wheel static balance wheel well or dull;
4. Workpiece speed is too high;
5 infeed is too big;
6 wheel spindle bearing wear, the gap is too large, resulting runout;
7 wheel or bench pressing means "crawl" and so on.
Surface of the workpiece surface reproduction burns often during grinding burns, burns there are several types, one burns machining direction along the wheel, dark black patches; Second, was the line or intermittent line shape.
Workpiece surface grinding process of being burned, summed up in the following reasons:
1 wheel too hard or too fine granularity tissue too dense;
(2) Feed excessive cutting fluid supply, cooling conditions are poor;
3. Workpiece speed is too low, wheel speed too fast;
4 wheel runout is too large, constantly changing due to grinding depth and burn;
5 dresser dressing is not timely or bad;
6 diamond sharp dresser bad;
7. Workpiece coarse grinding burns too deep, grinding allowance is too small, no worn;
8 Workpiece clamping force or suction deficiencies in the grinding force, the workpiece stops phenomenon exists.
Then the workpiece surface in the grinding process of how to know if it works burned? This is accomplished by periodic acid to check it out.
Workpiece after pickling, the surface is wet, should immediately astigmatism lamp visual inspection, the normal surface was uniformly dark gray. If so software point, showing dark clouds like black spots, and the entire perimeter uncertain; if decarbonization, is rendered dark gray or black piebald; if grinding cracks, the crack was cracked like, yes burns, one surface along Wheel machining direction showing dark black plaques, two lines are present or intermittent lines like. If the grinding process in the burn-in phenomenon, must promptly analyze the causes and take effective measures to solve them, to eliminate bulk burns.
Mainly the surface roughness of the surface roughness of the bearing parts are standard and process requirements, but in the processing and ultra-fine grinding process, for various reasons, often less than the specified requirements.
Mainly the surface roughness caused mainly due to:
1 grinding speed is too low, too fast feed rate, feed excessive, no feed grinding time is too short;
2. Workpiece speed is too high or the workpiece axis and the wheel axis vibration is too large;
3 wheel size is too coarse or too soft;
4 wheel dresser too fast or trimming mechanism gap is too large;
5 diamond wheel dressing is not sharp or of poor quality;
6 ultra-fine oil stone quality is not good, the installation location is not correct;
7 ultra-precision quality is mainly kerosene;
8 ultra-precise time is too short.
deep groove ball bearing in the grinding process, the work surface is achieved by high-speed rotation of the grinding wheel, grinding so if you do not follow the operating instructions for operation and adjust the device, it will work in the bearing surface of various defects, which affects The overall quality of the bearing.
Bearing surfaces are crossed spiral traces traces happen mainly due to poor wheel of the bus straight, there is uneven phenomenon, grinding, grinding wheel and the workpiece is only partial contact bearing, when the workpiece or wheel back and forth several times after exercise , the performance will be reproduced in the workpiece and the cross-helix can be observed visually. The pitch of the helix and the workpiece table speed, the size of workpiece speed, but also with the wheel axis is not parallel to the guide lines and the table.
(A) The main reason for the formation of helix
1 Dresser bad, not chamfered corners, unused coolant to be trimmed;
2 table guide rail lubricant too much, resulting workbench floating;
3 machine precision is not good;
4 grinding pressure is too big.
(B) forming the bearing surfaces having the spiral cause
1.V shaped rail rigidity bad, when an offset grinding wheel, but wheel edge in contact with the work surface;
2 noisy wheel dressing table commutation speed is unstable, accuracy is not high, so that the edge of a grinding wheel dressing slightly less;
3. Workpiece itself rigidity;
4 wheel has broken too flaking grit and the workpiece grinding wheel under the iron plot attached to the surface, this should be a good dressing wheel with cooling water wash or scrub clean;
5 wheel dressing well, there are local projections and so on.
Surface appears scaly scaly surface reproduces the main reason is due to traces of grinding wheel cutting edge is not sharp enough, in the grinding occurs when "eating to live" phenomenon, when large vibration.
Resulting in surface appears scaly traces of the specific reasons are:
A grinding wheel surface litter and oil thing;
2 Wheel untrimmed round;
3 wheel blunt. Dressing sharp enough;
4 fastening frame is not solid diamond, diamond or diamond quality is bad not shake sharp;
5 Wheel hardness uneven.
Face nap nap surface reproduces the main reason is due to traces of coarse grains shed, grain sandwiched between the workpiece and the grinding wheel and cause.
Workpiece surface grinding was napping in the specific reasons are:
1 coarse grinding traces left behind, grinding when not worn;
2 coolant coarse grains and tiny grains filter is not clean;
3 coarse abrasive wheel just trimmed off easily when;
4 toughness validity or grinding wheel is too soft;
5 abrasive workpiece material toughness with toughness and improper.
Have a direct bearing surface waveform traces we milled workpiece cut a cross-section perpendicular axis line and zoom, you can see the surrounding approximately sinusoidal. So that the center line along the axis of rotation without translation, the track is the sine waveform around the cylinder, which is also known as a polygon. Generating direct wave because the wheel moves relative to the workpiece or the grinding wheel on the workpiece by cyclically changing pressure and vibration caused by the exigencies. This vibration may be forced vibration, it may be self-excited vibration, thus directly on the workpiece often more than one wave frequency.
Direct waveform traces generated specific reasons are:
A grinding wheel spindle gap is too large;
2 Wheel hardness is too high;
3 wheel static balance wheel well or dull;
4. Workpiece speed is too high;
5 infeed is too big;
6 wheel spindle bearing wear, the gap is too large, resulting runout;
7 wheel or bench pressing means "crawl" and so on.
Surface of the workpiece surface reproduction burns often during grinding burns, burns there are several types, one burns machining direction along the wheel, dark black patches; Second, was the line or intermittent line shape.
Workpiece surface grinding process of being burned, summed up in the following reasons:
1 wheel too hard or too fine granularity tissue too dense;
(2) Feed excessive cutting fluid supply, cooling conditions are poor;
3. Workpiece speed is too low, wheel speed too fast;
4 wheel runout is too large, constantly changing due to grinding depth and burn;
5 dresser dressing is not timely or bad;
6 diamond sharp dresser bad;
7. Workpiece coarse grinding burns too deep, grinding allowance is too small, no worn;
8 Workpiece clamping force or suction deficiencies in the grinding force, the workpiece stops phenomenon exists.
Then the workpiece surface in the grinding process of how to know if it works burned? This is accomplished by periodic acid to check it out.
Workpiece after pickling, the surface is wet, should immediately astigmatism lamp visual inspection, the normal surface was uniformly dark gray. If so software point, showing dark clouds like black spots, and the entire perimeter uncertain; if decarbonization, is rendered dark gray or black piebald; if grinding cracks, the crack was cracked like, yes burns, one surface along Wheel machining direction showing dark black plaques, two lines are present or intermittent lines like. If the grinding process in the burn-in phenomenon, must promptly analyze the causes and take effective measures to solve them, to eliminate bulk burns.
Mainly the surface roughness of the surface roughness of the bearing parts are standard and process requirements, but in the processing and ultra-fine grinding process, for various reasons, often less than the specified requirements.
Mainly the surface roughness caused mainly due to:
1 grinding speed is too low, too fast feed rate, feed excessive, no feed grinding time is too short;
2. Workpiece speed is too high or the workpiece axis and the wheel axis vibration is too large;
3 wheel size is too coarse or too soft;
4 wheel dresser too fast or trimming mechanism gap is too large;
5 diamond wheel dressing is not sharp or of poor quality;
6 ultra-fine oil stone quality is not good, the installation location is not correct;
7 ultra-precision quality is mainly kerosene;
8 ultra-precise time is too short.
deep groove ball bearing in the grinding process, the work surface is achieved by high-speed rotation of the grinding wheel, grinding so if you do not follow the operating instructions for operation and adjust the device, it will work in the bearing surface of various defects, which affects The overall quality of the bearing.
2013年8月23日星期五
Oil-bearing support bearing assembly rotating
Oil-bearing assembly of the supporting shaft. Its rings and rolling elements are precision machined. Bearing in the factory, in order to protect the surface of the raceways and rolling elements are not corroded, in between the raceways and rolling elements into a rust grease oil or rust.
Bearings should be cleaned before installation. With anti-rust oil sealed bearing directly available gasoline or kerosene cleaning; thick oil or grease rust rust charged shall, light mineral oil, such as 10 # transformer oil heating oil or fat will melt cooled, then gasoline or kerosene to clean. Sides with shields or seals bearing grease at the factory joined, so when you do not have to clean install. Coated with anti-rust lubricant oil dual IKO cross roller bearings, the installation also without cleaning. In cleaning the installation process, should prevent foreign matter falling into the bearings, the result of slight abrasive will cause between the rolling element and raceway wear, increased noise and vibration.
Oil-bearing assembly and disassembly, mainly through two ways. First, the interference rings onto the shaft or pressed into the bearing hole; First, by heating up a large diameter bearing it, or cooling the bearing outer diameter narrowing it will be easily mounted on the shaft bearing seat or push hole. When pressurized mode, mechanical force or fluid pressure through a dedicated device will force acts directly on the assembly and disassembly of the seat ring, and never allow loading and unloading of force pass through the rolling. Otherwise it will cause the surface of the raceway and rolling elements indentation, resulting in increased noise and vibration damage. If a heating or cooling means for detachably, the heating temperature should be strictly controlled or cooling temperatures. Because the strength of the bearing surface microstructure by the structure of the metal surface, the temperature is too high will cause the tempering effect; temperature was too low will cause embrittlement of the metal surface. Typically the heating temperature does not exceed 100 ℃, the cooling must not end at the lowest temperature of minus 50 ℃. Also to be considered to be uniform heating.
Practice has proved that non-oil bearing improper installation causes premature bearing damage is one of the reasons. The ferrule assembly and disassembly with the interference is a very difficult thing, so the design of supports, we must consider how IKO cross roller bearing assembly and disassembly and easy assembly and disassembly of the problem. For heavy machinery assembly and disassembly of large bearings often need to design special equipment. If the high-pressure oil removal would need to be designed accordingly oil, pipes and pumps.
Bearings should be cleaned before installation. With anti-rust oil sealed bearing directly available gasoline or kerosene cleaning; thick oil or grease rust rust charged shall, light mineral oil, such as 10 # transformer oil heating oil or fat will melt cooled, then gasoline or kerosene to clean. Sides with shields or seals bearing grease at the factory joined, so when you do not have to clean install. Coated with anti-rust lubricant oil dual IKO cross roller bearings, the installation also without cleaning. In cleaning the installation process, should prevent foreign matter falling into the bearings, the result of slight abrasive will cause between the rolling element and raceway wear, increased noise and vibration.
Oil-bearing assembly and disassembly, mainly through two ways. First, the interference rings onto the shaft or pressed into the bearing hole; First, by heating up a large diameter bearing it, or cooling the bearing outer diameter narrowing it will be easily mounted on the shaft bearing seat or push hole. When pressurized mode, mechanical force or fluid pressure through a dedicated device will force acts directly on the assembly and disassembly of the seat ring, and never allow loading and unloading of force pass through the rolling. Otherwise it will cause the surface of the raceway and rolling elements indentation, resulting in increased noise and vibration damage. If a heating or cooling means for detachably, the heating temperature should be strictly controlled or cooling temperatures. Because the strength of the bearing surface microstructure by the structure of the metal surface, the temperature is too high will cause the tempering effect; temperature was too low will cause embrittlement of the metal surface. Typically the heating temperature does not exceed 100 ℃, the cooling must not end at the lowest temperature of minus 50 ℃. Also to be considered to be uniform heating.
Practice has proved that non-oil bearing improper installation causes premature bearing damage is one of the reasons. The ferrule assembly and disassembly with the interference is a very difficult thing, so the design of supports, we must consider how IKO cross roller bearing assembly and disassembly and easy assembly and disassembly of the problem. For heavy machinery assembly and disassembly of large bearings often need to design special equipment. If the high-pressure oil removal would need to be designed accordingly oil, pipes and pumps.
Roller bearing raceway sounds unusual
Bearing raceway raceway sound and control the sound is running when the bearing, its rolling body raceway rolling issued a slippery continuous sound is unique will happen all the bearings of the basic sound. Sound that is generally bearing raceway sound with other sounds. Greater rigidity of the bearing seat, roll sound pressure level is lower. If the radial clearance is too small, the rolling sound pressure level and the main frequency will decrease as the radial clearance increases dramatically.
roller bearing fatigue failure is a failure surface forms, mainly for fatigue crack initiation, propagation and fracture processes in alternating load faults arising under long-term effects of the metal.
1 .. Overall eccentric bearing low precision approach: use specified levels of precision bearings.
2 .. spindle is bent or housing bore misalignment methods: Repair spindle or cabinet.
3 belt too tight: Adjust the belt so that proper tightness.
4 poor lubrication Methods: provide grade lubricating material and properly cleaned.
5 low quality assembly methods: improving the quality of assembly.
6 bearing housing laps: Replace worn bearings and related components.
7 large axial force method: cleaning, alignment ring seals the gap between the requirements of 0.2 ~ 0.3mm, correct impeller balance hole diameter and the checksum static equilibrium values.
8 Bearing damage: replace the bearings.
Control raceway sound methods are: selection of low-noise bearings that waviness small bearings, judicious selection of the conditions of use. Raceway sound often affect the entire mechanical noise reduction raceway sound can reduce the overall mechanical noise.
roller bearing fatigue failure is a failure surface forms, mainly for fatigue crack initiation, propagation and fracture processes in alternating load faults arising under long-term effects of the metal.
1 .. Overall eccentric bearing low precision approach: use specified levels of precision bearings.
2 .. spindle is bent or housing bore misalignment methods: Repair spindle or cabinet.
3 belt too tight: Adjust the belt so that proper tightness.
4 poor lubrication Methods: provide grade lubricating material and properly cleaned.
5 low quality assembly methods: improving the quality of assembly.
6 bearing housing laps: Replace worn bearings and related components.
7 large axial force method: cleaning, alignment ring seals the gap between the requirements of 0.2 ~ 0.3mm, correct impeller balance hole diameter and the checksum static equilibrium values.
8 Bearing damage: replace the bearings.
Control raceway sound methods are: selection of low-noise bearings that waviness small bearings, judicious selection of the conditions of use. Raceway sound often affect the entire mechanical noise reduction raceway sound can reduce the overall mechanical noise.
2013年8月22日星期四
Requirements for machine tool spindle bearings
In the machine tool bearings, bearings is widely used. Spindle bearing with certain technical requirements. Introduce to you the following analysis
1 speed and temperature
With the development of science and technology, more and more high speed bearings, speed range and thus the greater the bearing high speed stability requirements are also increasing. Machine tool spindle bearing temperature is an important factor in limiting speed of the bearing. Under normal circumstances, the right choice bearing type, tolerance levels, configuration, clearance (preload) size, lubricants and lubrication, etc., to a certain extent, improve the speed performance of rolling bearings.
(2) carrying capacity and life
The general machine tool, the life of the main spindle assembly to maintain accuracy of the spindle is its period of use, therefore, required to maintain the accuracy bearing spindle assembly performance to meet life requirements. For heavy-duty machine tools or powerful cutting machine, you should first consider the bearing capacity.
3 stiffness and vibration resistance
To ensure the quality of the machining, the spindle system must have sufficient rigidity, otherwise it will have a greater re-mapping error even flutter. Vibration resistance refers to the forced vibration and self-excited vibration capability. Spindle assembly vibration resistance depends on the spindle and bearing stiffness and damping. Using the preload bearing can effectively increase the stiffness of the spindle system.
4 Noise
In high-speed grinder, the grinding noise and bearing noise is the main ingredient should be used in low-noise rolling bearings.
1 speed and temperature
With the development of science and technology, more and more high speed bearings, speed range and thus the greater the bearing high speed stability requirements are also increasing. Machine tool spindle bearing temperature is an important factor in limiting speed of the bearing. Under normal circumstances, the right choice bearing type, tolerance levels, configuration, clearance (preload) size, lubricants and lubrication, etc., to a certain extent, improve the speed performance of rolling bearings.
(2) carrying capacity and life
The general machine tool, the life of the main spindle assembly to maintain accuracy of the spindle is its period of use, therefore, required to maintain the accuracy bearing spindle assembly performance to meet life requirements. For heavy-duty machine tools or powerful cutting machine, you should first consider the bearing capacity.
3 stiffness and vibration resistance
To ensure the quality of the machining, the spindle system must have sufficient rigidity, otherwise it will have a greater re-mapping error even flutter. Vibration resistance refers to the forced vibration and self-excited vibration capability. Spindle assembly vibration resistance depends on the spindle and bearing stiffness and damping. Using the preload bearing can effectively increase the stiffness of the spindle system.
4 Noise
In high-speed grinder, the grinding noise and bearing noise is the main ingredient should be used in low-noise rolling bearings.
Cause bearing failure caused
According to the bearing surface grinding metamorphic layer formation mechanism, the impact grinding metamorphic layer of the main factors is the grinding heat and grinding force. The following analysis on the reasons for bearing failure.
1 bearing the grinding heat
The roller bearing grinding, the grinding wheel and the workpiece contact area, consume large amounts of energy, resulting in a large number of grinding heat, causing the local instantaneous grinding zone temperature. Use of linear motion heat transfer theory derivation, calculation or application infrared and thermocouple method measured the instantaneous temperature under experimental conditions can be found in the 0.1 ~ 0.001ms instantaneous temperature within the grinding zone up to 1000 ~ 1500 ℃. Such instantaneous temperature, a certain depth sufficient to work the surface layer of high temperature oxidation, amorphous structure, high-temperature tempering, secondary hardening, cracking and other changes or burns.
(1) the surface oxide layer
The instantaneous high temperature steel surface under the role of oxygen in the air, up into very thin (20 ~ 30nm) thin layer of iron oxide. It should be noted that the oxide layer thickness and the total thickness of the surface layer of grinding deterioration test results showed a corresponding relationship. This shows that the thickness of the oxide layer which is directly related with the grinding process, the grinding quality is an important symbol.
(2) amorphous tissue layer
Instantaneous grinding zone so that the surface temperature reaches a molten state, the molten metal molecular flow has been evenly coated on the work surface, and is the base metal at breakneck speed cooling, forming a thin layer of amorphous tissue layer. It has high hardness and toughness, but it is only about 10nm, it is easy to be removed precision grinding.
(3) high-temperature tempering layer
Instantaneous grinding zone temperature to a certain depth can (10 ~ 100nm) is heated to a temperature above the tempering heating the workpiece. Does not reach the austenitizing temperature in the case, as the heating temperature is increased, the surface layer by layer will be generated corresponding to the temperature of the heating or tempering retempered organizational changes, hardness is decreased. The higher the heating temperature, the hardness decreased also more powerful.
1 bearing the grinding heat
The roller bearing grinding, the grinding wheel and the workpiece contact area, consume large amounts of energy, resulting in a large number of grinding heat, causing the local instantaneous grinding zone temperature. Use of linear motion heat transfer theory derivation, calculation or application infrared and thermocouple method measured the instantaneous temperature under experimental conditions can be found in the 0.1 ~ 0.001ms instantaneous temperature within the grinding zone up to 1000 ~ 1500 ℃. Such instantaneous temperature, a certain depth sufficient to work the surface layer of high temperature oxidation, amorphous structure, high-temperature tempering, secondary hardening, cracking and other changes or burns.
(1) the surface oxide layer
The instantaneous high temperature steel surface under the role of oxygen in the air, up into very thin (20 ~ 30nm) thin layer of iron oxide. It should be noted that the oxide layer thickness and the total thickness of the surface layer of grinding deterioration test results showed a corresponding relationship. This shows that the thickness of the oxide layer which is directly related with the grinding process, the grinding quality is an important symbol.
(2) amorphous tissue layer
Instantaneous grinding zone so that the surface temperature reaches a molten state, the molten metal molecular flow has been evenly coated on the work surface, and is the base metal at breakneck speed cooling, forming a thin layer of amorphous tissue layer. It has high hardness and toughness, but it is only about 10nm, it is easy to be removed precision grinding.
(3) high-temperature tempering layer
Instantaneous grinding zone temperature to a certain depth can (10 ~ 100nm) is heated to a temperature above the tempering heating the workpiece. Does not reach the austenitizing temperature in the case, as the heating temperature is increased, the surface layer by layer will be generated corresponding to the temperature of the heating or tempering retempered organizational changes, hardness is decreased. The higher the heating temperature, the hardness decreased also more powerful.
2013年8月21日星期三
Type of angular contact ball bearings
Angular contact ball bearings: 7000C-type (α = 15 °), 7000AC type (α = 25 °) and 7000B (α = 40 °) of several types. This kind of bearing locking in the outer ring, inner and outer rings can not be separated, can be combined radial and axial loads and axial loads in one direction. Axial load capacity determined by the contact angle, the contact angle is larger, the ability to withstand high axial loads. This kind of bearing shaft or housing to limit axial displacement in one direction. Contact ball bearing high speed limit, you can support radial load and axial load can also be subject to pure axial load, axial load capacity determined by the contact angle, and with the contact angle increases.
Single row angular contact ball bearings
Single row angular contact ball bearing can withstand axial load in one direction, the radial load, will cause additional axial force must be applied to the corresponding reverse load, therefore, the types of bearings are generally used in pairs. Double row angular contact ball bearings can withstand greater radial load mainly radial and axial joint load and moment load, it can limit the bi-axial displacement of shaft or housing, the contact angle of 30 degrees.
Angular contact ball bearings installed in pairs
Installed in pairs of angular contact ball bearings can bear radial load mainly radial and axial joint load can also be subject to pure radial loads. Tandem configuration can only bear axial load in one direction, the other two configurations can withstand axial load in either direction. This type of bearings are generally manufacturers matching pairs of user submitted after installation preload interference, rings and balls in the axial pre-load condition, thereby enhancing the entire group as a single bearing support stiffness and rotation Accuracy
Single row angular contact ball bearings
Single row angular contact ball bearing can withstand axial load in one direction, the radial load, will cause additional axial force must be applied to the corresponding reverse load, therefore, the types of bearings are generally used in pairs. Double row angular contact ball bearings can withstand greater radial load mainly radial and axial joint load and moment load, it can limit the bi-axial displacement of shaft or housing, the contact angle of 30 degrees.
Angular contact ball bearings installed in pairs
Installed in pairs of angular contact ball bearings can bear radial load mainly radial and axial joint load can also be subject to pure radial loads. Tandem configuration can only bear axial load in one direction, the other two configurations can withstand axial load in either direction. This type of bearings are generally manufacturers matching pairs of user submitted after installation preload interference, rings and balls in the axial pre-load condition, thereby enhancing the entire group as a single bearing support stiffness and rotation Accuracy
The materials used slewing
ring and rolling element materials
Under normal circumstances, slewing bearing using-hardened carbon chromium bearing steel. Or GCr15SiMn GCr15 steel grades for manufacturing; slewing rings hardened steel is used when the user no special requirements, generally used in 50Mn steel, but sometimes in order to meet some of the needs of specific application hosts can also be provided by user specific conditions of use use other brands of hardened steel.
cage materials
Slewing ring with a cage with the overall style, segmented, isolated block structure of the form. Where overall style and segmented cage with 20 gauge steel or cast aluminum alloy ZL102. Isolated block 1010 by polyamide resin, ZL102 cast aluminum and other manufacturing.
seal material
Slewing ring with oil resistant nitrile rubber material used manufacture.
Under normal circumstances, slewing bearing using-hardened carbon chromium bearing steel. Or GCr15SiMn GCr15 steel grades for manufacturing; slewing rings hardened steel is used when the user no special requirements, generally used in 50Mn steel, but sometimes in order to meet some of the needs of specific application hosts can also be provided by user specific conditions of use use other brands of hardened steel.
cage materials
Slewing ring with a cage with the overall style, segmented, isolated block structure of the form. Where overall style and segmented cage with 20 gauge steel or cast aluminum alloy ZL102. Isolated block 1010 by polyamide resin, ZL102 cast aluminum and other manufacturing.
seal material
Slewing ring with oil resistant nitrile rubber material used manufacture.
2013年8月20日星期二
Talking grinder hydrostatic bearing maintenance experience
Rotary hydrostatic bearing its high accuracy, good rigidity, high capacity, no wear, high durability and is widely used M210, M131W, 3160A grinder and 2A710, FYT10 Diamond boring head. With the development of digital technology, hydrostatic bearings are also widely used in machining centers, CNC machine tool spindles. YTO AG first engine plant, there are many static pressure and static pressure diamond grinder boring head, in the maintenance carried out some exploration and attempts to obtain experience points.
Orifice restrictor (a) outside the internal throttle to throttle, and to install the upper and lower chamber pressure gauge real-time display. So easy maintenance, in particular, can easily be cleaned regularly, this is an internal restrictor unmatched. (2) throttling ratio. Throttling than the theoretical value of β is 1.2 to 1.5, and 1.25 based on years of experience with preferred. So that the maintenance, the need for geometric precision spindle, bearing around the geometric accuracy, concentricity, roundness and taper strictly controlled in order to ensure β values. According to the carrying capacity of the machine to determine the value of e (the geometric center of the spindle and bearing eccentricity), the β value best. (3) is not installed in the oil chamber spindle, each column of oil out of the oil port must be consistent (observation), if not, should be taken to change the restrictor aperture methods to alter the flow. With 4 cavities, for example, generally lower, left and right chamber of the oil column at between 20 ~ 25mm, hole diameter of 0.25 ~ 0.4mm.
Thin film feedback Feedback restrictor throttle special bearing stiffness is great, but the machine in operation often appear hold tile, brushed, lost pressure and so on. The most critical is the feedback film film practice that locking bush, brushed the main reasons are: ① thin plastic deformation due; ② feedback slow. External load mutation, the film did not react when the axis and tile has been rubbed; ③ film fatigue. Film using a long time, fatigue deformation, the equivalent of changing the feedback parameters. Increasing film thickness and use some of the fatigue resistance of the material, can receive good results. Generally rigid film, a pre-load, reserve gap approach. Specific approach is: the 1.4mm thick rigid 4mm thick film to film, the inferior vena pad 0.05mm thick aluminum foil, so that the spindle than the ideal position to adjust to the high position of 0.05mm. Purpose is force when the spindle (wheel weights, cutting force) after return exactly to the ideal center.
Hydrostatic bearing oil supply system improvement in the fuel supply system, in addition to the coarse filter, fine filter, the rest of the components have a protective effect on the hydrostatic bearing. On the basis of the original system, fuel system improvements. (A) in the throttle plate after the oil pressure switch and pressure gauge connection port (the original in the accumulator in front), so that the operator can see the chamber pressure and the size of the inlet pressure. When the pressure is greater than a certain value, in order to immediately shut down, in order to avoid bearing locking. Such as: inlet pressure 2MPa, exit chamber pressure 1.2 ~ 1.6MPa, 1.2MPa below will shut down. (2) increasing the number of detection means hydrostatic bearing between the shaft and the bearing gap of 0.04 ~ 0.05mm, during which the oil has a certain resistance value of the resistance variation detection, it can learn the size of the gap . With spindle pole, bush for another pole, measure the resistance change. After processing this signal sent to the photoelectric alarms and control system amplifier, controls the spindle motor start and stop, in order to avoid friction axis and tile.
Orifice restrictor (a) outside the internal throttle to throttle, and to install the upper and lower chamber pressure gauge real-time display. So easy maintenance, in particular, can easily be cleaned regularly, this is an internal restrictor unmatched. (2) throttling ratio. Throttling than the theoretical value of β is 1.2 to 1.5, and 1.25 based on years of experience with preferred. So that the maintenance, the need for geometric precision spindle, bearing around the geometric accuracy, concentricity, roundness and taper strictly controlled in order to ensure β values. According to the carrying capacity of the machine to determine the value of e (the geometric center of the spindle and bearing eccentricity), the β value best. (3) is not installed in the oil chamber spindle, each column of oil out of the oil port must be consistent (observation), if not, should be taken to change the restrictor aperture methods to alter the flow. With 4 cavities, for example, generally lower, left and right chamber of the oil column at between 20 ~ 25mm, hole diameter of 0.25 ~ 0.4mm.
Thin film feedback Feedback restrictor throttle special bearing stiffness is great, but the machine in operation often appear hold tile, brushed, lost pressure and so on. The most critical is the feedback film film practice that locking bush, brushed the main reasons are: ① thin plastic deformation due; ② feedback slow. External load mutation, the film did not react when the axis and tile has been rubbed; ③ film fatigue. Film using a long time, fatigue deformation, the equivalent of changing the feedback parameters. Increasing film thickness and use some of the fatigue resistance of the material, can receive good results. Generally rigid film, a pre-load, reserve gap approach. Specific approach is: the 1.4mm thick rigid 4mm thick film to film, the inferior vena pad 0.05mm thick aluminum foil, so that the spindle than the ideal position to adjust to the high position of 0.05mm. Purpose is force when the spindle (wheel weights, cutting force) after return exactly to the ideal center.
Hydrostatic bearing oil supply system improvement in the fuel supply system, in addition to the coarse filter, fine filter, the rest of the components have a protective effect on the hydrostatic bearing. On the basis of the original system, fuel system improvements. (A) in the throttle plate after the oil pressure switch and pressure gauge connection port (the original in the accumulator in front), so that the operator can see the chamber pressure and the size of the inlet pressure. When the pressure is greater than a certain value, in order to immediately shut down, in order to avoid bearing locking. Such as: inlet pressure 2MPa, exit chamber pressure 1.2 ~ 1.6MPa, 1.2MPa below will shut down. (2) increasing the number of detection means hydrostatic bearing between the shaft and the bearing gap of 0.04 ~ 0.05mm, during which the oil has a certain resistance value of the resistance variation detection, it can learn the size of the gap . With spindle pole, bush for another pole, measure the resistance change. After processing this signal sent to the photoelectric alarms and control system amplifier, controls the spindle motor start and stop, in order to avoid friction axis and tile.
Sliding bearing pad material and structure
Sliding bearing bush materials and structures Abstract: sheet metal fixture design the automatic lathe turning 3Cr13 stainless steel parts auto stringer processing technology and equipment selection composite thread cutting cycle G76 command coordinate system and the direction of motion profile gantry WEDM decoding software simulation program design is based on UG CAD / CAM capabilities of the new mouse design and manufacturing machine Xiazuo Association: towards "quality service brand association" principle introduced Seiko continue efforts to launch low-power inverter high ripple rejection Voltage Regulator is rolling wheel Mixer procedures developed bearing ultra-precision machine tools for metal cutting fluid waste breakthrough treatment CITIC Heavy Machinery and Qi a machine made of heavy-duty double column vertical lathe cylinder head valve seat and the conduit hole processing technology AC610M / AC630M turning grade precision CNC milling typical CAM platform application programming features contrast world machine tool industry development direction of how to solve the Chinese full parsing Pro / E after AutoCAD drawing Chinese characters to the garbage problem detection technology application prospects in the automotive industry structural materials bearing corrosion friction and wear-resistant alloy bearing lubrication strength ability to withstand load bearing parts in direct contact with a relative motion to reduce friction and wear bush material put forward various demands required to meet the following abrasion friction coefficient of friction with sufficient strength to withstand the impact of fatigue strength capability bearing alloy thickness of 0.0130. 13mm sticky load speed bearing lubrication gap is too small surface finish material adverse Note carefully selected matches prevented.
The bearing pad directly in contact with the shaft portion, the shaft having to bear the load and relative motion. To reduce friction, wear on the bearing materials put forward various demands, in addition to requirements of friction between the friction coefficient, wear outside should also meet the following points:
1 should have sufficient compressive strength, fatigue strength and ability to withstand shocks. Bearing alloy having a thickness of (0.013-0.13) mm.
2 block resistance is good. When the load, high speed bearings, bearing clearance is too small, the surface finish is not high, poor lubrication, pay attention carefully selected matching material to prevent friction wear an adhesive glue.
3 with the adaptability and the ability to accommodate foreign matter. Low hardness, good plasticity and low coefficient of elasticity of the material has good adaptability and the ability to accommodate foreign matter.
4 good corrosion resistance, low price, sources foot. After the oxidation of colloidal sediments, have a corrosive effect on the bearing materials.
The bearing pad directly in contact with the shaft portion, the shaft having to bear the load and relative motion. To reduce friction, wear on the bearing materials put forward various demands, in addition to requirements of friction between the friction coefficient, wear outside should also meet the following points:
1 should have sufficient compressive strength, fatigue strength and ability to withstand shocks. Bearing alloy having a thickness of (0.013-0.13) mm.
2 block resistance is good. When the load, high speed bearings, bearing clearance is too small, the surface finish is not high, poor lubrication, pay attention carefully selected matching material to prevent friction wear an adhesive glue.
3 with the adaptability and the ability to accommodate foreign matter. Low hardness, good plasticity and low coefficient of elasticity of the material has good adaptability and the ability to accommodate foreign matter.
4 good corrosion resistance, low price, sources foot. After the oxidation of colloidal sediments, have a corrosive effect on the bearing materials.
2013年8月19日星期一
Bearing basic knowledge and exception handling
Generally inside the bearing inner ring, outer ring, rolling elements and cage composed of four parts. For sealed bearings, further comprising a lubricant and a seal of two parts. Bearing at work, able to withstand the radial load or axial load, at a certain rotational speed, it will produce radial runout or axial runout. According to the working conditions of the bearing used to choose different types of bearings, bearing in order to better play the function, and can extend bearing life.
Life of roll bearings performance, because different purposes, in the required period to maintain their performance. Even though the correct bearing for a particular purpose will, after some time, noise, vibration increases, resulting in decline in accuracy due to wear, grease aging, fatigue, peeling rolling surface can no longer be used. Until these bearings can not be used in a broad sense during the bearing life. Each of them is known as: noise life, wear life, the grease life, the rolling fatigue life and so on.
Why bearing damage? Only a part of the bearing damage in practical applications. Most bearing applications over the life of the machine or the device itself. Bearing damage for many reasons - more than the anticipated load, non-tight seal with or caused by too small bearing clearance and so on. Any one factor has its special form of damage, and will leave special signs of damage. Therefore, to view damage to the bearings, in most cases you can find its possible factors, and based on these findings, the measures taken to prevent recurrence.
Generally speaking, a third of the bearing damage causes damage based on fatigue, another third reason is poor lubrication, the other one-third of contaminants into the bearing or improper installation process. Bearing damage is also associated with different forms of industrial relevance. For example, the electronics industry on the indoor temperature is higher, which requires fans must twenty-four hours operation, the fan bearings are mostly due to material fatigue caused damage; while the pulp and paper industry is mostly due to poor lubrication or bearing damage caused by pollution. Why bearing will fail prematurely? .
Improper assembly
All kinds of bearing failure in advance, 16% were due to improper assembly and not caused by the use of assembly tools. Some devices require the use of mechanical, hydraulic or heating method for proper and efficient installation and removal. Using special tools and techniques for professional assembly, is to achieve the maximum extension of the machine running time another solution.
Improper lubrication
Although you can install a variety of "maintenance free" sealed bearings, bearings fail prematurely but there are still 36% is due to the incorrect application of grease technology and improper use. Any improper lubrication of the bearings will inevitably fail in advance of normal life. Since the bearing is usually the most difficult mechanical handling equipment part lubrication problem occurs infrequently.
Pollution
Bearings are precision parts, if the bearings and grease contamination will not operate effectively. In addition, as has been marked with grease maintenance-free sealed bearings all use only a small portion of the bearing, so all the early failure of the bearing at least 14% is due to problems caused by pollution.
Fatigue.
If the machine becomes overloaded, use or improper maintenance, the bearings will be affected, leading to premature failure of the bearing, 34% were due to fatigue caused by. Since the bearing in the maintenance of inappropriate or excessive stress would be given "early warning", so the equipment operator or maintenance personnel to observe the operation of the bearing performance anomalies. Why bearings require lubrication? In theory, a good lubrication in the ideal working conditions, the bearing life will always be met, of course, is simply not possible, but if the correct lubrication of bearings, bearing the longest working life. Bearing lubrication to reduce friction and wear within the bearing to prevent the sticking, its lubricating effect is as follows:
1, reducing friction and wear. Constituting the bearing rings, rolling elements and the mutual contact portion of the holder form a film, even in the case of heavy load, but also to prevent the metal contacts, reducing friction and wear.
2, the fatigue life.
Fatigue life of the rolling bearing, the rolling contact surface of the rotary good lubrication, is extended; otherwise, oil viscosity lubricant film thickness of the well bottom, is shortened.
3, the discharge frictional heat and cooling.
Circulating oil to the oil discharge method and the like can be generated by friction heat, the heat coming from the external cooling. Prevent bearing overheating, prevent oil itself aging. .
4, other.
Prevent dust and debris inside the bearing, or to prevent rust, corrosion effect.
Life of roll bearings performance, because different purposes, in the required period to maintain their performance. Even though the correct bearing for a particular purpose will, after some time, noise, vibration increases, resulting in decline in accuracy due to wear, grease aging, fatigue, peeling rolling surface can no longer be used. Until these bearings can not be used in a broad sense during the bearing life. Each of them is known as: noise life, wear life, the grease life, the rolling fatigue life and so on.
Why bearing damage? Only a part of the bearing damage in practical applications. Most bearing applications over the life of the machine or the device itself. Bearing damage for many reasons - more than the anticipated load, non-tight seal with or caused by too small bearing clearance and so on. Any one factor has its special form of damage, and will leave special signs of damage. Therefore, to view damage to the bearings, in most cases you can find its possible factors, and based on these findings, the measures taken to prevent recurrence.
Generally speaking, a third of the bearing damage causes damage based on fatigue, another third reason is poor lubrication, the other one-third of contaminants into the bearing or improper installation process. Bearing damage is also associated with different forms of industrial relevance. For example, the electronics industry on the indoor temperature is higher, which requires fans must twenty-four hours operation, the fan bearings are mostly due to material fatigue caused damage; while the pulp and paper industry is mostly due to poor lubrication or bearing damage caused by pollution. Why bearing will fail prematurely? .
Improper assembly
All kinds of bearing failure in advance, 16% were due to improper assembly and not caused by the use of assembly tools. Some devices require the use of mechanical, hydraulic or heating method for proper and efficient installation and removal. Using special tools and techniques for professional assembly, is to achieve the maximum extension of the machine running time another solution.
Improper lubrication
Although you can install a variety of "maintenance free" sealed bearings, bearings fail prematurely but there are still 36% is due to the incorrect application of grease technology and improper use. Any improper lubrication of the bearings will inevitably fail in advance of normal life. Since the bearing is usually the most difficult mechanical handling equipment part lubrication problem occurs infrequently.
Pollution
Bearings are precision parts, if the bearings and grease contamination will not operate effectively. In addition, as has been marked with grease maintenance-free sealed bearings all use only a small portion of the bearing, so all the early failure of the bearing at least 14% is due to problems caused by pollution.
Fatigue.
If the machine becomes overloaded, use or improper maintenance, the bearings will be affected, leading to premature failure of the bearing, 34% were due to fatigue caused by. Since the bearing in the maintenance of inappropriate or excessive stress would be given "early warning", so the equipment operator or maintenance personnel to observe the operation of the bearing performance anomalies. Why bearings require lubrication? In theory, a good lubrication in the ideal working conditions, the bearing life will always be met, of course, is simply not possible, but if the correct lubrication of bearings, bearing the longest working life. Bearing lubrication to reduce friction and wear within the bearing to prevent the sticking, its lubricating effect is as follows:
1, reducing friction and wear. Constituting the bearing rings, rolling elements and the mutual contact portion of the holder form a film, even in the case of heavy load, but also to prevent the metal contacts, reducing friction and wear.
2, the fatigue life.
Fatigue life of the rolling bearing, the rolling contact surface of the rotary good lubrication, is extended; otherwise, oil viscosity lubricant film thickness of the well bottom, is shortened.
3, the discharge frictional heat and cooling.
Circulating oil to the oil discharge method and the like can be generated by friction heat, the heat coming from the external cooling. Prevent bearing overheating, prevent oil itself aging. .
4, other.
Prevent dust and debris inside the bearing, or to prevent rust, corrosion effect.
Special bearing material selection considerations
Bearing alloys: mainly tin, lead, antimony, or other metals, also known as white metal roll bearings alloy. Because of its good wear resistant, high plasticity, ran together good performance, good thermal conductivity and resistance to rubber and oil resistance and good absorption and therefore suitable for heavy, high-speed case, the bearing strength of the alloy, low price expensive, use must be cast in bronze, steel or cast iron bearing, to form a thin coating.
1, plastic bearings: plastic bearings have greater compressive strength and wear resistance, commonly used bearings Plastic Bakelite, nylon, PTFE and so on. Lubricating oil and water are available, but also a self-lubricating properties, but poor thermal conductivity.
2, the porous metal material: a porous tissue, the porous metal material is a powder. If it is immersed in lubricant, allowing the pores filled with oil, into oil bearing, self-lubricating properties. Porous metal material toughness is small, only suitable for stationary and non-impact load, the low-speed situations.
To improve the sliding performance and life of the bearing, bearing information should choose these factors into account. Bearings and bearing liner information collectively referred to as bearing materials, bearing wear and journal information, bearing their own materials, lubricants and lubrication directly related.
1, plastic bearings: plastic bearings have greater compressive strength and wear resistance, commonly used bearings Plastic Bakelite, nylon, PTFE and so on. Lubricating oil and water are available, but also a self-lubricating properties, but poor thermal conductivity.
2, the porous metal material: a porous tissue, the porous metal material is a powder. If it is immersed in lubricant, allowing the pores filled with oil, into oil bearing, self-lubricating properties. Porous metal material toughness is small, only suitable for stationary and non-impact load, the low-speed situations.
To improve the sliding performance and life of the bearing, bearing information should choose these factors into account. Bearings and bearing liner information collectively referred to as bearing materials, bearing wear and journal information, bearing their own materials, lubricants and lubrication directly related.
2013年8月17日星期六
Deep groove ball bearing seals applications
Deep groove ball bearing is the bearing seal member in the normal operation in the harsh environment of the key components, bearing seals protect bearings from erosion and pollution of the bearing lubrication in a good clean conditions, extending bearing life.
Generally, deep groove ball bearing seals greater role than the dust cover, and by rotating flexible and low speed rotation restrictions. Bearing seals in the design, we must consider the performance of lubricants and conveyor systems and ideal working conditions.
For bearing applications in use to withstand high loads, a strong impact force and prevent water and dust particles such as rust invasion, and developed a new type of high load capacity, sealed, clean and lubricated bearing seals.
Experience has shown that in a polluted working conditions, easy to enter the bearing clastic particles, and these particles can damage the raceway debris, causing stress concentration. Also, if uneven lubrication, hard contact of the metal surface, resulting in a slight "peeling" corrupted, the contact area can lead to stress concentration, so that these two results of the stress concentration of the metal surface crack spread and ultimately shorten bearing life.
Studies show that, by changing the organization of bearing steel, impurity contamination can be improved bearing lubrication conditions or under conditions edge working life, to improve the bearing stress concentration at the edge of the release ability.
The best practical protection measures are bearing: When the impurity one appears, then stop it. New deep groove ball bearing seals of both these two advantages. The new hole type bearing seals only solve suppress a negative pressure in the bearing to prevent the water, the main sealing member is not directly exposed to water, the water from "breathing", but also play an impurity blocking the recess slot at the function. Conventional bearing seals the rotating and the stationary state is a linear contact, to maintain the strength of the tight sealing performance of the sealing member and this work, the contact instead of linear contact with the surface to accommodate the bearing rotating sealing requirements, both tight seal, not produce a large negative pressure.
To confirm the new hole type bearing seals the effectiveness of the test, the bearing operating speed range to 100r/min 700r/min, and 294kN radial load is continuously applied while the water spray of about 100L/min. General hole bearing seals in this period, the negative pressure increases, while the new-hole bearing seals inhibited the negative, to ensure the normal operation of the work
Generally, deep groove ball bearing seals greater role than the dust cover, and by rotating flexible and low speed rotation restrictions. Bearing seals in the design, we must consider the performance of lubricants and conveyor systems and ideal working conditions.
For bearing applications in use to withstand high loads, a strong impact force and prevent water and dust particles such as rust invasion, and developed a new type of high load capacity, sealed, clean and lubricated bearing seals.
Experience has shown that in a polluted working conditions, easy to enter the bearing clastic particles, and these particles can damage the raceway debris, causing stress concentration. Also, if uneven lubrication, hard contact of the metal surface, resulting in a slight "peeling" corrupted, the contact area can lead to stress concentration, so that these two results of the stress concentration of the metal surface crack spread and ultimately shorten bearing life.
Studies show that, by changing the organization of bearing steel, impurity contamination can be improved bearing lubrication conditions or under conditions edge working life, to improve the bearing stress concentration at the edge of the release ability.
The best practical protection measures are bearing: When the impurity one appears, then stop it. New deep groove ball bearing seals of both these two advantages. The new hole type bearing seals only solve suppress a negative pressure in the bearing to prevent the water, the main sealing member is not directly exposed to water, the water from "breathing", but also play an impurity blocking the recess slot at the function. Conventional bearing seals the rotating and the stationary state is a linear contact, to maintain the strength of the tight sealing performance of the sealing member and this work, the contact instead of linear contact with the surface to accommodate the bearing rotating sealing requirements, both tight seal, not produce a large negative pressure.
To confirm the new hole type bearing seals the effectiveness of the test, the bearing operating speed range to 100r/min 700r/min, and 294kN radial load is continuously applied while the water spray of about 100L/min. General hole bearing seals in this period, the negative pressure increases, while the new-hole bearing seals inhibited the negative, to ensure the normal operation of the work
Bearing fits and tolerances with tolerance class
1 tolerance level of choice
And bearing with the shaft or bearing bore tolerance level and precision of the bearing. And P0-level precision bearing with the shaft, the tolerance level is generally IT6, bearing hole is generally IT7. The rotating accuracy and smooth running applications with higher requirements (such as electric motors, etc.) should be selected axis IT5, bearing hole is IT6.
2 the tolerance zone selection
Equivalent radial load P is divided into "light", "normal" and "heavy" load, such as several cases, with the bearing dynamic load rating C of the relationship:
Light load normal load P ≤ 0.06C 0.06C <P ≤ 0.12C heavy loads 0.12C <P
1) shaft tolerance
Install radial bearings and angular contact bearings with reference to the corresponding shaft tolerance tolerance zone tables. For most applications, the shaft rotation and radial load direction unchanged, ie the bearing inner ring rotates relative to the loading direction of the occasion, the general should choose transition or interference fit. Stationary shaft and radial load direction unchanged, ie the bearing inner ring is stationary relative to the loading direction of the occasion, you can choose the transition or a small gap with (too much clearance is not allowed).
2) shell hole tolerance zone
Install radial bearings and angular contact bearings with reference to the corresponding shell hole tolerance zone tolerance table. Select the attention to the load direction oscillating or rotating outer ring, you should avoid clearance fit. Equivalent radial load also affects the size of the outer ring with the selection.
3) the choice of bearing structure
Roll bearings seat unless there are special needs, and more generally with the overall structure, split bearing only in the assembly have difficulty, or the advantages of easy assembly on a main consideration when used, but it can not be applied to a tight fit or a more precise fit, for example, than the K7 K7 and tighter fit, and if the tolerance class IT6 or more sophisticated bore are not using split bearing.
And bearing with the shaft or bearing bore tolerance level and precision of the bearing. And P0-level precision bearing with the shaft, the tolerance level is generally IT6, bearing hole is generally IT7. The rotating accuracy and smooth running applications with higher requirements (such as electric motors, etc.) should be selected axis IT5, bearing hole is IT6.
2 the tolerance zone selection
Equivalent radial load P is divided into "light", "normal" and "heavy" load, such as several cases, with the bearing dynamic load rating C of the relationship:
Light load normal load P ≤ 0.06C 0.06C <P ≤ 0.12C heavy loads 0.12C <P
1) shaft tolerance
Install radial bearings and angular contact bearings with reference to the corresponding shaft tolerance tolerance zone tables. For most applications, the shaft rotation and radial load direction unchanged, ie the bearing inner ring rotates relative to the loading direction of the occasion, the general should choose transition or interference fit. Stationary shaft and radial load direction unchanged, ie the bearing inner ring is stationary relative to the loading direction of the occasion, you can choose the transition or a small gap with (too much clearance is not allowed).
2) shell hole tolerance zone
Install radial bearings and angular contact bearings with reference to the corresponding shell hole tolerance zone tolerance table. Select the attention to the load direction oscillating or rotating outer ring, you should avoid clearance fit. Equivalent radial load also affects the size of the outer ring with the selection.
3) the choice of bearing structure
Roll bearings seat unless there are special needs, and more generally with the overall structure, split bearing only in the assembly have difficulty, or the advantages of easy assembly on a main consideration when used, but it can not be applied to a tight fit or a more precise fit, for example, than the K7 K7 and tighter fit, and if the tolerance class IT6 or more sophisticated bore are not using split bearing.
Bearing precision grinding surface grinding by Trace Analysis
Bearing in precision grinding, due to the rough demanding work surface grinding marks often appear to the naked eye can trace its surface grinding, mainly the following: First, the performance of cross spiral traces. This occurs mainly due to traces wheel bus straight poor, there is uneven phenomenon, in the grinding, the grinding wheel is only partial contact with the workpiece when the workpiece or the wheel back and forth several times after exercise, the performance will be reproduced in the workpiece cross helix, and can be observed visually. The pitch of the helix and the workpiece table speed, the size of workpiece speed, but also with the wheel axis is not parallel to the guide lines and the table.
(A) the roller bearing surfaces of the main spiral form
1 Dresser bad, not chamfered corners, unused coolant to be trimmed;
2 table guide rail lubricant too much, resulting workbench floating;
3 machine precision is not good;
4 grinding pressure is too big.
(B) with the formation of the bearing causes the helix
1.V shaped rail rigidity bad, when an offset grinding wheel, but wheel edge in contact with the work surface;
2 wheel dressing table when commutation speed is unstable, the accuracy is not high, so that one edge of the dressing wheel is slightly less;
3. Workpiece itself rigidity;
4 wheel has broken too flaking grit and the workpiece grinding wheel under the iron plot attached to the surface, this should be a good dressing wheel with cooling water wash or scrub clean;
5 wheel dressing well, there are local projections and so on.
(A) the roller bearing surfaces of the main spiral form
1 Dresser bad, not chamfered corners, unused coolant to be trimmed;
2 table guide rail lubricant too much, resulting workbench floating;
3 machine precision is not good;
4 grinding pressure is too big.
(B) with the formation of the bearing causes the helix
1.V shaped rail rigidity bad, when an offset grinding wheel, but wheel edge in contact with the work surface;
2 wheel dressing table when commutation speed is unstable, the accuracy is not high, so that one edge of the dressing wheel is slightly less;
3. Workpiece itself rigidity;
4 wheel has broken too flaking grit and the workpiece grinding wheel under the iron plot attached to the surface, this should be a good dressing wheel with cooling water wash or scrub clean;
5 wheel dressing well, there are local projections and so on.
Deep groove ball bearings constitute a major component characteristics
Deep groove ball bearing due purposes and working conditions are different, there are many changes in its structure, but the basic structure is from the inner ring, outer ring, rolling elements (balls) and cage four parts.
An inner ring (also known as the inner sleeve or inner ring). Normally fixed in the journal, the inner ring rotates with the shaft. The outer surface of the inner ring with balls or rollers for rolling grooves, called an inner groove or inner raceway.
Second, the outer ring (also known as a jacket or outer ring). Normally fixed to the bearing housing or the housing of the machine, from the effect of the rolling element bearing balls. Surface of the outer ring also has a ball or roller for rolling groove, called internal or inner raceway groove.
Third, the rolling elements (balls). Each groove ball bearings are equipped with one or more groups of rolling elements, mounted between the inner and outer rings, the transfer from the rolling force. The rolling body is the load bearing part, the shape, size and number determines the load capacity of the bearings are subjected to high speed performance.
Four, the cage (also known as cage or isolator). The bearing of the rolling bodies evenly spaced, so that each rolling element between the inner ring and the outer ring rolling normally. In addition, the cage has guided rolling motion, improve internal bearing lubrication conditions and to prevent rolling off and so on.
In the thrust ball bearing, and the shaft with ferrule called shaft washer, and housing or machine casing with ferrule box office, shaft ring and seat ring gasket collectively. In addition to the four parts, the various configurations of the bearing and other parts of its mating. For example, rivets, dust cover, seals, washers, retaining rings and tight sets and so on.
An inner ring (also known as the inner sleeve or inner ring). Normally fixed in the journal, the inner ring rotates with the shaft. The outer surface of the inner ring with balls or rollers for rolling grooves, called an inner groove or inner raceway.
Second, the outer ring (also known as a jacket or outer ring). Normally fixed to the bearing housing or the housing of the machine, from the effect of the rolling element bearing balls. Surface of the outer ring also has a ball or roller for rolling groove, called internal or inner raceway groove.
Third, the rolling elements (balls). Each groove ball bearings are equipped with one or more groups of rolling elements, mounted between the inner and outer rings, the transfer from the rolling force. The rolling body is the load bearing part, the shape, size and number determines the load capacity of the bearings are subjected to high speed performance.
Four, the cage (also known as cage or isolator). The bearing of the rolling bodies evenly spaced, so that each rolling element between the inner ring and the outer ring rolling normally. In addition, the cage has guided rolling motion, improve internal bearing lubrication conditions and to prevent rolling off and so on.
In the thrust ball bearing, and the shaft with ferrule called shaft washer, and housing or machine casing with ferrule box office, shaft ring and seat ring gasket collectively. In addition to the four parts, the various configurations of the bearing and other parts of its mating. For example, rivets, dust cover, seals, washers, retaining rings and tight sets and so on.
2013年8月9日星期五
Knowledge of angular contact ball bearings
First, the process planning principles:
1, the quality principles. Must be processed according to the process of the final product quality to meet the requirements of the relevant drawings or documents.
2, the benefit principle. Consider the production arrangement to facilitate and enhance productivity and so on.
3, the economic principles. Meet the requirements of the premise, considering the possibility of reducing costs.
4, taking into account the operator's labor intensity, and environmental protection.
Second, the process of the preparation of the basic steps:
A familiar figure and related products enterprise standards and national standards and customer requirements.
2, to understand the various requirements of rough drawings.
3, the proposed process route, select Positioning benchmarks and installation.
4 Select allowance, calculated step size to determine the conditions and test methods.
5, to determine each step processing equipment. Process is determined, you must first process test, verify its correctness, rationality, economy and so on. Meanwhile, the process has a temporary and relative, production processes used will change because of some objective conditions necessary to make the appropriate adjustments.
Three, angular contact ball bearing Basics:
1, the contact angle: the rolling element and raceway contact points or the midpoint of the line of contact with the radial tangent plane angle. A
There are two different kinds of bearings can contact angle (such as tapered roller bearings), the general said contact angle refers to the external antennae.
Angular contact ball bearings can withstand radial and axial load, but also can withstand pure axial load. As the contact angle increases,
It can withstand axial load increases. High speed limit.
The same dimensions, sometimes depending on the required load bearing different, can be designed to be non-loaded ball gap and the ball gap two kinds. There ball gap can hold more of the ball, can withstand greater loads, but using lower speed. There is also a relatively unique double row angular contact ball bearings, the so-called first generation wheel hub bearing, there are two inner ring and an outer ring.
2, angular contact ball bearings precision. Is divided into five,
0,6,5,4,2-level, followed by level from low to high. General Bearing logo on the back, preceded by the letters P, and use the "/" separated, such as 7203C/P4, but not marked P0 stage omitted. Different accuracy levels have different sizes and rotation precision tolerances, the higher the level, the higher the finished product required, thus the component parts of the various requirements are also higher.
3 clearance. Four-point contact ball bearings and double row angular contact ball bearing axial clearance required national standards. Four-point contact ball bearing axial clearance points
C2, C0, C3, C4 four groups, double row angular contact ball bearing axial clearance of C2, C0, C3 three groups, C2 smallest group, C0 group does not identify the product. There are also some clearance requirements may not be assembled according to the national standard,
Mainly based on customer specific requirements adoption. Single row angular contact ball bearing clearance is no uniform requirement, but to control the contact angle tolerances, product drawing generally marked radial clearance requirements.
1, the quality principles. Must be processed according to the process of the final product quality to meet the requirements of the relevant drawings or documents.
2, the benefit principle. Consider the production arrangement to facilitate and enhance productivity and so on.
3, the economic principles. Meet the requirements of the premise, considering the possibility of reducing costs.
4, taking into account the operator's labor intensity, and environmental protection.
Second, the process of the preparation of the basic steps:
A familiar figure and related products enterprise standards and national standards and customer requirements.
2, to understand the various requirements of rough drawings.
3, the proposed process route, select Positioning benchmarks and installation.
4 Select allowance, calculated step size to determine the conditions and test methods.
5, to determine each step processing equipment. Process is determined, you must first process test, verify its correctness, rationality, economy and so on. Meanwhile, the process has a temporary and relative, production processes used will change because of some objective conditions necessary to make the appropriate adjustments.
Three, angular contact ball bearing Basics:
1, the contact angle: the rolling element and raceway contact points or the midpoint of the line of contact with the radial tangent plane angle. A
There are two different kinds of bearings can contact angle (such as tapered roller bearings), the general said contact angle refers to the external antennae.
Angular contact ball bearings can withstand radial and axial load, but also can withstand pure axial load. As the contact angle increases,
It can withstand axial load increases. High speed limit.
The same dimensions, sometimes depending on the required load bearing different, can be designed to be non-loaded ball gap and the ball gap two kinds. There ball gap can hold more of the ball, can withstand greater loads, but using lower speed. There is also a relatively unique double row angular contact ball bearings, the so-called first generation wheel hub bearing, there are two inner ring and an outer ring.
2, angular contact ball bearings precision. Is divided into five,
0,6,5,4,2-level, followed by level from low to high. General Bearing logo on the back, preceded by the letters P, and use the "/" separated, such as 7203C/P4, but not marked P0 stage omitted. Different accuracy levels have different sizes and rotation precision tolerances, the higher the level, the higher the finished product required, thus the component parts of the various requirements are also higher.
3 clearance. Four-point contact ball bearings and double row angular contact ball bearing axial clearance required national standards. Four-point contact ball bearing axial clearance points
C2, C0, C3, C4 four groups, double row angular contact ball bearing axial clearance of C2, C0, C3 three groups, C2 smallest group, C0 group does not identify the product. There are also some clearance requirements may not be assembled according to the national standard,
Mainly based on customer specific requirements adoption. Single row angular contact ball bearing clearance is no uniform requirement, but to control the contact angle tolerances, product drawing generally marked radial clearance requirements.
Angular contact ball bearings grinding super process planning
Real craft card shall state each step of the process parameters of the product requirements, such as grinding outer channel step, specify a channel diameter, roundness, ditch location, groove curvature, channel shape, roughness and other requirements, as well as workpiece speed, wheel speed, eccentricity, bearing angle, light grinding time and other parameters.
The process should be based on the processing site and precision requirements, the provisions of a good size, shape and position tolerances, roughness and other requirements. Geometric tolerance tolerance refers to the shape and position tolerances. Form tolerances are: ① face flatness; ② oval and cylindrical inner and outer diameters degree; ③ channel curvature ellipse, roundness error, etc.; raceway oval, angular deviation, straightness and so on. Position tolerances are: ① width variation; ② center of the channel parallel to the base surface; ③ the inner diameter of the inner vertical face of the base, the outer diameter of the base of the vertical plane; ④ channel inside diameter, outside diameter of the beating ;
P4 class bearings:
P4 class bearings generally use high speed, a variety of performance is higher, so the process more than the average product, the process requirements are relatively high.
a. outer grinding process route (one kind):
Coarse grind coarse face → face → OD → coarse coarse coarse outer diameter of the channel → → → coarse slope stability tempering → fine
OD grinding mill channel → → → stable tempered OD grinding lapping end → → → grinding diameter grinding outer diameter grinding channel → →
Ultra-fine grinding slope → → Lapping OD channel
I generally coarse than finely ground margin, margin finely grinding off than a large margin, grinding allowance should be noted that appropriate margin is too large, easy to cause deformation and burn rings, too little margin, unable to produce the next process step on the road to eliminate errors and generate scrap, usually talk about the amount of inner and outer diameters of the left direction. Positioning surface or bearing surface should be higher than under the procedures of various shape and position tolerances higher. End mill grinding amount should be possible to make both ends, as in the vertical shaft surface grinder grinding double face, should be non-base surface grinding, regrinding the base surface, the base surface of the ferrule OD, ID, channel, etc. processing procedures, testing benchmarks, also bearing assembly, installation benchmarks. Vertical Spindle Surface Grinding face grinding, the grinding non-base surface to determine the size. Double face grinding mill double face, generally by adjusting both sides of the wheel speed to reach both ends of the grinding amount equal to the surface than the narrow end ferrule wide wheel speed is high. Mill channel, the coarse and fine grinding, the groove position can be made when the base surface (a ramp) offset a little bit of control (must be strictly controlled, calculated or drawing comparison to determine), due to the relatively small margin may be appropriate to avoid the phenomenon of the channel while there is no wear. As outer bearing surface to improve the accuracy of positioning or support for the removal of the last printing, the need for the grinding margin is generally 1 ~ 2μ. Ultra-fine grinding locking channel generally placed after the ultra-precision relative pair due to difficult to control when they need to try to channel grinding tolerances few more compression to ensure locking height headroom height when grinding locking can stay 6 ~ 10μ (unilateral margin). If the ultra-fine grinding locking on channel after channel side easily in the presence of glitches, seriously affecting product performance (vibration, life, etc.).
P0-bearing:
Outer grinding process route (one kind):
Coarse face → (coarse grind end) → → coarse channel coarse outer slopes → → coarse grinding OD → (grinding diameter) → Channel → grinding ultra-fine grinding trench slope → → fine Grinding Lapping OD OD →
b. inner grinding process route (one kind):
Coarse face → face → coarse coarse grind coarse channel inner and outer → → → coarse inner diameter grinding coarse ramp → → Research
→ OD grinding mill grinding diameter channel → → → ultra-fine grinding trench slope
The upper process is not unique, each enterprise and the device should be based on the situation, the strength of technology and control methods for the preparation, etc., to adjust, particularly when grinding the inner ring, a bearing inner ring channel and the inner or outer bearing grinding channel mill channel.
While some also require grinding outer diameter of the ferrule there are many structures, the need to carefully analyze the product structure and geometric tolerances, roughness and other requirements, the preparation of grinding processes.
angular contact ball bearing assembly process preparation:
Assembly process must ensure that the assembled product assembly diagram products fully comply with the requirements, as well as other requirements of the project, such as residual magnetism, typing, flexibility, and appearance. Yes assembly process technology cards, matching tables and clearance, the contact angle, the channel diameter required list and other components.
P4 level assembly process craft card:
Inner and outer rings lettering demagnetization Cleaning → Inspection → Accessories → Cleaning → ferrule ferrule surface quality inspection → → sampling channel roughness values reinspection ball rules and sub-rules value → → outer channel size sorting heating, assembly kits → radial clearance sampling precision rotation → cleaning → test → test finished appearance and flexibility, vibration detecting residual magnetism, etc. → → test → test contact angle width of the projection amount → test → cleaning, cleanliness inspection → → Inner packing rust , packing (packing list according to requirements)
The contents of each step should have the instrument used and technical requirements, etc. P5 or general level, just a sampling of some processes or omitted.
The process should be based on the processing site and precision requirements, the provisions of a good size, shape and position tolerances, roughness and other requirements. Geometric tolerance tolerance refers to the shape and position tolerances. Form tolerances are: ① face flatness; ② oval and cylindrical inner and outer diameters degree; ③ channel curvature ellipse, roundness error, etc.; raceway oval, angular deviation, straightness and so on. Position tolerances are: ① width variation; ② center of the channel parallel to the base surface; ③ the inner diameter of the inner vertical face of the base, the outer diameter of the base of the vertical plane; ④ channel inside diameter, outside diameter of the beating ;
P4 class bearings:
P4 class bearings generally use high speed, a variety of performance is higher, so the process more than the average product, the process requirements are relatively high.
a. outer grinding process route (one kind):
Coarse grind coarse face → face → OD → coarse coarse coarse outer diameter of the channel → → → coarse slope stability tempering → fine
OD grinding mill channel → → → stable tempered OD grinding lapping end → → → grinding diameter grinding outer diameter grinding channel → →
Ultra-fine grinding slope → → Lapping OD channel
I generally coarse than finely ground margin, margin finely grinding off than a large margin, grinding allowance should be noted that appropriate margin is too large, easy to cause deformation and burn rings, too little margin, unable to produce the next process step on the road to eliminate errors and generate scrap, usually talk about the amount of inner and outer diameters of the left direction. Positioning surface or bearing surface should be higher than under the procedures of various shape and position tolerances higher. End mill grinding amount should be possible to make both ends, as in the vertical shaft surface grinder grinding double face, should be non-base surface grinding, regrinding the base surface, the base surface of the ferrule OD, ID, channel, etc. processing procedures, testing benchmarks, also bearing assembly, installation benchmarks. Vertical Spindle Surface Grinding face grinding, the grinding non-base surface to determine the size. Double face grinding mill double face, generally by adjusting both sides of the wheel speed to reach both ends of the grinding amount equal to the surface than the narrow end ferrule wide wheel speed is high. Mill channel, the coarse and fine grinding, the groove position can be made when the base surface (a ramp) offset a little bit of control (must be strictly controlled, calculated or drawing comparison to determine), due to the relatively small margin may be appropriate to avoid the phenomenon of the channel while there is no wear. As outer bearing surface to improve the accuracy of positioning or support for the removal of the last printing, the need for the grinding margin is generally 1 ~ 2μ. Ultra-fine grinding locking channel generally placed after the ultra-precision relative pair due to difficult to control when they need to try to channel grinding tolerances few more compression to ensure locking height headroom height when grinding locking can stay 6 ~ 10μ (unilateral margin). If the ultra-fine grinding locking on channel after channel side easily in the presence of glitches, seriously affecting product performance (vibration, life, etc.).
P0-bearing:
Outer grinding process route (one kind):
Coarse face → (coarse grind end) → → coarse channel coarse outer slopes → → coarse grinding OD → (grinding diameter) → Channel → grinding ultra-fine grinding trench slope → → fine Grinding Lapping OD OD →
b. inner grinding process route (one kind):
Coarse face → face → coarse coarse grind coarse channel inner and outer → → → coarse inner diameter grinding coarse ramp → → Research
→ OD grinding mill grinding diameter channel → → → ultra-fine grinding trench slope
The upper process is not unique, each enterprise and the device should be based on the situation, the strength of technology and control methods for the preparation, etc., to adjust, particularly when grinding the inner ring, a bearing inner ring channel and the inner or outer bearing grinding channel mill channel.
While some also require grinding outer diameter of the ferrule there are many structures, the need to carefully analyze the product structure and geometric tolerances, roughness and other requirements, the preparation of grinding processes.
angular contact ball bearing assembly process preparation:
Assembly process must ensure that the assembled product assembly diagram products fully comply with the requirements, as well as other requirements of the project, such as residual magnetism, typing, flexibility, and appearance. Yes assembly process technology cards, matching tables and clearance, the contact angle, the channel diameter required list and other components.
P4 level assembly process craft card:
Inner and outer rings lettering demagnetization Cleaning → Inspection → Accessories → Cleaning → ferrule ferrule surface quality inspection → → sampling channel roughness values reinspection ball rules and sub-rules value → → outer channel size sorting heating, assembly kits → radial clearance sampling precision rotation → cleaning → test → test finished appearance and flexibility, vibration detecting residual magnetism, etc. → → test → test contact angle width of the projection amount → test → cleaning, cleanliness inspection → → Inner packing rust , packing (packing list according to requirements)
The contents of each step should have the instrument used and technical requirements, etc. P5 or general level, just a sampling of some processes or omitted.
Seal type deep groove ball bearings
Many deep groove ball bearing sealing problems mainly ineffective drain grease and dust, etc., in a nutshell is poor sealing performance; non-contact seals no big problem, the main problem is multi-contact seals. What are the causes it?
Main bearing seal structure is relatively backward. Seal structure lies in the rotary member of the seal groove and the sealing cap sealing lips. Sealed general there are three forms, one does not actually slot; second is a small inner diameter, there is a step; third is a complete seal groove.
Sealing lip with a single and double lip of the points, to improve the sealing effect, we believe that the sealing lips should be developed and groove seal structure, because this form of contact seals and labyrinth seals combined sealing effect is better, but the process is complicated, higher cost.
In the modern enterprise in the pursuit of cost-premise, as far as possible the pursuit of double lip seal and groove seal structure deep groove ball bearings, but conditions were not under seal structure can only produce a general, after all, is now a large domestic use part of the sealing structure in general, and the sealing structure by many users.
Main bearing seal structure is relatively backward. Seal structure lies in the rotary member of the seal groove and the sealing cap sealing lips. Sealed general there are three forms, one does not actually slot; second is a small inner diameter, there is a step; third is a complete seal groove.
Sealing lip with a single and double lip of the points, to improve the sealing effect, we believe that the sealing lips should be developed and groove seal structure, because this form of contact seals and labyrinth seals combined sealing effect is better, but the process is complicated, higher cost.
In the modern enterprise in the pursuit of cost-premise, as far as possible the pursuit of double lip seal and groove seal structure deep groove ball bearings, but conditions were not under seal structure can only produce a general, after all, is now a large domestic use part of the sealing structure in general, and the sealing structure by many users.
Deep groove ball bearing vibration noise root causes
Deep groove ball bearing vibration and noise on the formation mechanism of domestic and international aspects of the control of vibration and noise, there are two different approaches. Bearing vibration mainly from two sources:
One bearing bearing caused by external incentives inherent vibration, referring to the bearing inner ring, outer ring, rolling elements and cage the natural vibration.
Two deep groove ball bearing due to contact between moving parts forced vibration caused by collision, such as ball rolling is not an ideal sphere, inside and outside the channel contact point trajectory is not a perfect circle (roundness, waviness), the raceway not the ideal smooth surface (roughness) and the rolling elements and cage in motion collision and lubricants in the forced vibration caused by impurities, vibration and sound are closely related, but slightly different sense, That is the sound originated in vibration, acoustic vibrations in the air is transmitted to humans by the feeling of hearing, so the ultra-high frequency vibrations are inaudible. However, if the receiver and the sound vibration characteristics of the receiver is the same, two received signals received relevant to the whole, according to this view, controlling vibration or noise control can play the same effect. And because the vibration control is simple, so home and abroad priority control vibration to ensure product quality. Therefore, for the general bearing, it is recommended to concentrate its limited human and financial resources to do a good job of bearing vibration control. Quality standards should not separate the noise, of course, according to foreign experience for a special bearing products, such as computer hard drives, CD recorder drive system bearings, vibration assessment is not easy to use, can develop criteria to assess noise measurement method .
One bearing bearing caused by external incentives inherent vibration, referring to the bearing inner ring, outer ring, rolling elements and cage the natural vibration.
Two deep groove ball bearing due to contact between moving parts forced vibration caused by collision, such as ball rolling is not an ideal sphere, inside and outside the channel contact point trajectory is not a perfect circle (roundness, waviness), the raceway not the ideal smooth surface (roughness) and the rolling elements and cage in motion collision and lubricants in the forced vibration caused by impurities, vibration and sound are closely related, but slightly different sense, That is the sound originated in vibration, acoustic vibrations in the air is transmitted to humans by the feeling of hearing, so the ultra-high frequency vibrations are inaudible. However, if the receiver and the sound vibration characteristics of the receiver is the same, two received signals received relevant to the whole, according to this view, controlling vibration or noise control can play the same effect. And because the vibration control is simple, so home and abroad priority control vibration to ensure product quality. Therefore, for the general bearing, it is recommended to concentrate its limited human and financial resources to do a good job of bearing vibration control. Quality standards should not separate the noise, of course, according to foreign experience for a special bearing products, such as computer hard drives, CD recorder drive system bearings, vibration assessment is not easy to use, can develop criteria to assess noise measurement method .
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