Cylindrical roller bearings on the damage state, such as: roller bearing ring wall cards injury, may be considered as the reason, lack of lubricant, not suitable for oil discharge structure defects, foreign invasion, bearing misalignment, shaft The deflection is too large, there will be overlap of these reasons. Therefore, only the investigation bearing damage, injury is difficult to know the real reason. However, if you know the use of mechanical bearings, conditions of use, bearing the surrounding structure, to understand the situation before and after the accident, combined with state of the bearing damage, and several reasons, we can prevent similar incidents from recurring.
Preload method is divided into radial and axial preload preload method for two categories, as described below.
1. Top tight radial radial preload method fado using the radial load of the tapered bore bearings, the typical example is precision double row cylindrical roller bearings, use nuts to adjust relative to the cylindrical roller bearing tapered shaft The axial position of the neck, so that the inner ring have the right to obtain the amount of radial expansion negative clearance, this method used for machine tool spindle and jet engines.
Adjusting the bushing or shim size to get the right amount of preload; also available through friction torque measurement or control starting to get the right preload; can directly use the pre-adjusted amount of preload to the bearing pairs of double to achieve the purpose of pretension, this time users generally do not need re-adjustment, in short, all through the axial preload the bearings, use the relative position certainly will not change. Constant pressure preload is to use helical springs, disc springs, etc. to get the right bearing preload method. Spring preload rigid - like much smaller than the rigidity of the bearing, so the constant pressure preload of cylindrical roller bearings relative position will change in use, but the amount of preload was largely unchanged.
Positioning preload and constant pressure preload is as follows:
(1) equal to the amount of preload, increasing the rigidity of the bearing position preloading effect is large and positioning changes in preload on rigid cylindrical roller bearing load impact is much smaller.
(2) positioned preload in use, the shaft and the bearing axial length of the temperature difference caused by the difference, the temperature difference between inner and outer rings caused by the amount of radial expansion and displacement caused by the load of the impact will preload volume changes; rather constant pressure preload in use, changes in preload negligible.
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