In the cross roller bearing grinding, the grinding wheel and the workpiece contact area, a small amount of energy consumption, the occurrence of a small amount of grinding heat, forming part of Shashi cryogenic grinding zone. Practical application of linear stationary heat transfer formula derivation, contemplating or applying red paint method and thermocouple method under test conditions Shashi measured temperature can be invented within the 0.1 ~ 0.001ms Shashi grinding zone temperature can be as high as 1000 to 1500 ℃. This instant cold enough to make the task certainly looks the outer surface of the depth of occurrence of low-temperature oxidation, amorphous tissue, tempering, secondary hardening, cracking or burn a variety of changes.
1, through the surface bearing quality feeling
Crossed roller bearings in the process a lot of customers that as long as the bearing surface brightness is of good quality, which is wrong. Bearing surfaces should be kind of bright glossy black, glossy black reasons causing this bearing steels are used in compliance with its grinding and cutting fluid used, such as arising, in which the former two based.
2, chamfer is bright
Bearing chamfer does not determine the quality of the bearing, but reflects the processing method of the bearing. Chamfer is black, shows that, after hardening heat treatment, thus increasing the hardness of cross roller bearings, and some people think that the chamfer is black does not look good is not processed completely, this is a misunderstanding.
3, one of the cage than two body good, although the use of new technology are integrated cage, but it is only saves material, while rotating, worse performance than the two bodies.
Overall, cross roller bearing life has a relationship with the three factors, namely the quality of the bearing itself. Second, the use of the environment. Third, the installation method.
2013年7月29日星期一
Crossed roller bearings during operation load causes injury card processing
The so-called injury card is wound the sliding surface of the bearing part generated summary slight burn surface damage arising. Slide surface, rolling surface circumferential direction of the linear scars. roller bearing linear scar near the end of the pendulum roller end surface of the card collar injury.
Bearing injury phenomenon occurs card:
Excessive load, excessive preload. Poor lubrication. Foreign objects. Tilt inner outer, shaft deflection. Shaft, bearing housing poor accuracy.
Bearing injury phenomenon occurs when the card measures:
Check the size of the load. Preload should be appropriate. Improved lubricants and lubrication methods. Check shaft, bearing housing precision.
Select the load vector with the first consideration should be the case relative to the rotation of the ferrule. In accordance with the synthetic radial load vector relative to the rotating ring case, composite ferrule exposure can be divided into: a fixed load, rotational load and oscillating load.
a. fixed load
Role in the synthesis of radial load on the ring by ring raceway of the local area is exposed, and transmitted to the shaft or bearing the appropriate local area, this load is called a fixed load. Its characteristics are synthetic radial load vector with ferrule relatively static. Directed to bear the load of the ring can be used looser fit.
b. rotational load
Acting on the radial load on the composite ring, the raceway along the circumferential direction of rotation, sequentially from the various parts of the exposure, this load called rotational load, the radial load characteristics of the synthesis vector with respect to the rotating ring. Withstand the rotational load of the ring tight fit to be elected, in exceptional circumstances, such as the load is very light, or under heavy load low speed only occasionally rings, bearings use hard materials and surface roughness is higher, rotating load to bear Rings can also be used looser fit.
c. swing load
Synthesis of acting on the ferrule fixed radial load direction, this load is called swing load or non-directional load, which is characterized by the synthesis of the ferrule effect radial load vectors ring raceway to swing within a certain area, certain areas of the roller is exposed, or the load acting on the bearing is an impact load, the vibration load, the direction of the load values change frequently. Have to bear the load swing bearing, outer ferrule with the state, with the housing bore should be a tight fit.
Bearing inner diameter and outer diameter tolerances are manufactured in accordance with the standard, the bearing inner ring and the shaft, the outer ring and housing bore with the tightness of the journal can only be controlled housing bore tolerances and tolerances to be achieved. Cross roller bearing inner ring and the shaft hole basis with the use of the bearing outer ring and housing bore with the introduction of machine axis system. Rolling with commonly used. With the correct choice, you must know the actual load bearing conditions, temperature and other requirements, and in fact it is very difficult. Therefore, in most cases is selected according refinements fit.
Bearing injury phenomenon occurs card:
Excessive load, excessive preload. Poor lubrication. Foreign objects. Tilt inner outer, shaft deflection. Shaft, bearing housing poor accuracy.
Bearing injury phenomenon occurs when the card measures:
Check the size of the load. Preload should be appropriate. Improved lubricants and lubrication methods. Check shaft, bearing housing precision.
Select the load vector with the first consideration should be the case relative to the rotation of the ferrule. In accordance with the synthetic radial load vector relative to the rotating ring case, composite ferrule exposure can be divided into: a fixed load, rotational load and oscillating load.
a. fixed load
Role in the synthesis of radial load on the ring by ring raceway of the local area is exposed, and transmitted to the shaft or bearing the appropriate local area, this load is called a fixed load. Its characteristics are synthetic radial load vector with ferrule relatively static. Directed to bear the load of the ring can be used looser fit.
b. rotational load
Acting on the radial load on the composite ring, the raceway along the circumferential direction of rotation, sequentially from the various parts of the exposure, this load called rotational load, the radial load characteristics of the synthesis vector with respect to the rotating ring. Withstand the rotational load of the ring tight fit to be elected, in exceptional circumstances, such as the load is very light, or under heavy load low speed only occasionally rings, bearings use hard materials and surface roughness is higher, rotating load to bear Rings can also be used looser fit.
c. swing load
Synthesis of acting on the ferrule fixed radial load direction, this load is called swing load or non-directional load, which is characterized by the synthesis of the ferrule effect radial load vectors ring raceway to swing within a certain area, certain areas of the roller is exposed, or the load acting on the bearing is an impact load, the vibration load, the direction of the load values change frequently. Have to bear the load swing bearing, outer ferrule with the state, with the housing bore should be a tight fit.
Bearing inner diameter and outer diameter tolerances are manufactured in accordance with the standard, the bearing inner ring and the shaft, the outer ring and housing bore with the tightness of the journal can only be controlled housing bore tolerances and tolerances to be achieved. Cross roller bearing inner ring and the shaft hole basis with the use of the bearing outer ring and housing bore with the introduction of machine axis system. Rolling with commonly used. With the correct choice, you must know the actual load bearing conditions, temperature and other requirements, and in fact it is very difficult. Therefore, in most cases is selected according refinements fit.
Correctly judge the cross roller bearings operating rules and fault
Bearing on its use during exhibit strong regularity and repeatability is very good. Normal quality bearings used in the beginning, vibration and noise are relatively small, but some scattered spectrum and amplitude are small, probably due to some flaws in the manufacturing process, such as surface burr due.
Exercise period of time, to maintain a certain level of vibration and noise, the spectrum is very simple, there is only one or two multiplier. Rarely occurs more than three times the frequency spectrum, bearing condition is very stable, into a stable working period.
Continue to run late into the use, cross roller bearing vibration and noise begins to increase, sometimes different sound, but the change in vibration increases more slowly this time, bearing kurtosis value starts suddenly reaches a certain value. We believe that at this time cross roller bearings that showed initial failure.
At this time, it is requested that the cross roller bearings for close monitoring, pay close attention to the changes. Since then, bearing kurtosis values began to decline rapidly, and close to normal, while the vibration and noise begins significantly increased, its growth began to accelerate significantly, when the vibration exceeds vibration standards (such as ISO2372 standard), and its bearing kurtosis value starts Rapid increases, when both exceed vibration standards, and kurtosis values than normal (available kurtosis relative standard), we believe that the bearing has entered the late failure of production, the need for timely maintenance equipment, replacement of cross roller bearings.
cross roller bearing exhibit advanced fault characteristics to a serious failure (generally axle bearing damage such as burns, sand shelf spallation, raceway, wear beads, etc.) is not more than one week big time, equipment, greater capacity, speed more quickly, and the shorter the interval. Therefore, the actual cross roller bearing fault diagnosis, once found fault with advanced features, should be decisive bearing faulty judgment, as soon as possible overhaul.
Exercise period of time, to maintain a certain level of vibration and noise, the spectrum is very simple, there is only one or two multiplier. Rarely occurs more than three times the frequency spectrum, bearing condition is very stable, into a stable working period.
Continue to run late into the use, cross roller bearing vibration and noise begins to increase, sometimes different sound, but the change in vibration increases more slowly this time, bearing kurtosis value starts suddenly reaches a certain value. We believe that at this time cross roller bearings that showed initial failure.
At this time, it is requested that the cross roller bearings for close monitoring, pay close attention to the changes. Since then, bearing kurtosis values began to decline rapidly, and close to normal, while the vibration and noise begins significantly increased, its growth began to accelerate significantly, when the vibration exceeds vibration standards (such as ISO2372 standard), and its bearing kurtosis value starts Rapid increases, when both exceed vibration standards, and kurtosis values than normal (available kurtosis relative standard), we believe that the bearing has entered the late failure of production, the need for timely maintenance equipment, replacement of cross roller bearings.
cross roller bearing exhibit advanced fault characteristics to a serious failure (generally axle bearing damage such as burns, sand shelf spallation, raceway, wear beads, etc.) is not more than one week big time, equipment, greater capacity, speed more quickly, and the shorter the interval. Therefore, the actual cross roller bearing fault diagnosis, once found fault with advanced features, should be decisive bearing faulty judgment, as soon as possible overhaul.
2013年7月24日星期三
Bearing installation basics
A, clear of bearing
Bearing the model number indicates the basic dimensions of the bearing, the original clearance, cage type, sealed form, lubrication requirements, so before starting the installation must be clearly bearing model is correct.
B, the positioning of the spherical roller bearing
A shaft for smooth operation, generally at least two pivot for axial and radial support, each with at least one or more pivot bearings. Generally, from a role in positioning the bearing, the other bearing is positioned afford effect. In exceptional circumstances, the role of the two bearings also act as positioning.
Locating bearing provides radial support and axial orientation. Therefore, locating bearing on the shaft and the bearing chamber must also be fixed. Deep groove ball bearings, spherical roller bearings, double row angular contact ball bearings, single row pair angular contact ball bearings can be used as locating bearing. A pair of tapered roller bearings can be used. No flange cylindrical roller bearings and a thrust bearing with radial clearance, they can be used as locating bearing.
Non-locating bearing only provides radial support, which must be able to move in the axial direction. By axial movement of the bearing itself (for example, cylindrical roller bearing), it can be supported with the bearing inner ring or outer ring of the relative movement.
Cross-locating bearing may be formed in at least one direction while the axial load ball bearings or roller bearings components.
Bearing the model number indicates the basic dimensions of the bearing, the original clearance, cage type, sealed form, lubrication requirements, so before starting the installation must be clearly bearing model is correct.
B, the positioning of the spherical roller bearing
A shaft for smooth operation, generally at least two pivot for axial and radial support, each with at least one or more pivot bearings. Generally, from a role in positioning the bearing, the other bearing is positioned afford effect. In exceptional circumstances, the role of the two bearings also act as positioning.
Locating bearing provides radial support and axial orientation. Therefore, locating bearing on the shaft and the bearing chamber must also be fixed. Deep groove ball bearings, spherical roller bearings, double row angular contact ball bearings, single row pair angular contact ball bearings can be used as locating bearing. A pair of tapered roller bearings can be used. No flange cylindrical roller bearings and a thrust bearing with radial clearance, they can be used as locating bearing.
Non-locating bearing only provides radial support, which must be able to move in the axial direction. By axial movement of the bearing itself (for example, cylindrical roller bearing), it can be supported with the bearing inner ring or outer ring of the relative movement.
Cross-locating bearing may be formed in at least one direction while the axial load ball bearings or roller bearings components.
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