Preload type and function of bearing

In many applications, positive or negative working clearance needs to be added to the bearing configuration. In most applications, the working clearance should be positive, but it also needs to be negative in many cases, such as machine tool spindle bearing, pinion bearing on automobile axle driver, small motor bearing configuration or bearing configuration for swing movement, that is, preload should be added to improve the rigidity of bearing configuration or operation accuracy.
Preload, such as spring compression, is also recommended for bearings operating at high speeds under no-load or very light load conditions. In these cases, the preload provides the minimum load for the bearing and prevents bearing damage due to rolling element slip.
Type of preload:
Depending on the type of bearing, the preload can be radial or axial. For example, cylindrical roller bearings can only bear radial preload due to their design characteristics, while thrust ball bearings and cylindrical roller thrust bearings can only bear axial preload.
Function of pre tightening:
1. Improve rigidity;
2. Reduce operating noise;
3. Improve the accuracy of shaft guidance;
4. Compensate for wear and settlement (sinking) during operation
5. Provide long service life.