Rolling bearing preloading methods are divided into two categories: radial preloading method and axial preloading method:
1. Radial preloading method and radial jacking method are mostly used in Among tapered bore bearings that bear radial loads, a typical example is a double row precision short cylindrical roller bearing. The nut is used to adjust the axial position of this bearing relative to the tapered journal so that the inner ring has a suitable expansion amount to obtain radial negative clearance. This method is mostly used in machine tool spindles and jet engines.
2. Axial preloading method Axial preloading method can be roughly divided into two types: positioning preloading and constant pressure preloading. In positioning preloading, the appropriate preloading amount can be obtained by adjusting the size of the bushing or gasket; the appropriate preloading amount can also be adjusted by measuring or controlling the starting friction torque; the preloading amount can also be directly adjusted using Pairs of double bearings are used to achieve the purpose of preloading. At this time, the user generally does not need to adjust. In short, the relative position of any bearing that has been axially preloaded will definitely not change during use.
Constant pressure preloading is a method of using coil springs, disc springs, etc. to ensure that bearings are properly preloaded. The rigidity of the preload spring is generally much smaller than the rigidity of the bearing, so the relative position of the constant pressure preloaded bearing will change during use, but the preload amount will remain roughly unchanged.
The comparison between positioning preload and constant pressure preload is as follows:
(1) When the preload amounts are equal, positioning preload has a greater effect on increasing bearing rigidity, and positioning The effect of rigidity changes on bearing load during preloading is also much smaller.
(2) When positioning preload is in use, the axial length difference caused by the temperature difference between the shaft and the bearing seat, the radial expansion caused by the temperature difference between the inner and outer rings, and the displacement caused by the load, etc. The influence of the pressure will cause the preload amount to change; while the constant pressure preload is in use, the change in preload can be ignored.