Why need to select a suitable bearing:

In order to get the best performance of the bearing, the inner ring and the shaft and the outer ring and the bearing hole must be properly matched. If the matching surface is not fully fit, under the external load, the bearing ring may be do circular motion in the shaft or bearing hole, this phenomenon is called "peristaltic". Once the surface with the peristaltic, will damage the shaft and bearing, and cause the bearing unnormal heat or wear.
In order to prevent peristaltic, it is not enough to press the bearing from axially direction, and the bearings that bear the rotating load must also provide the necessary interference fit. Bearings that beared static loads are generally not required to use interference fit unless the bearing is subjected to vibration loads.


The principle to select a suitable rolling mill bearing:
In order to select the most properly bearing, the direction of the load, the characteristics of the load, the size of the load, the temperature condition, the installation and dismantling conditions, and so on must be taken into account. Under normal conditions (means that there is no special requirements of the rotation accuracy, smooth operation, operating temperature), selection of metric series rolling bearings and shaft and bearing seat can be in accordance with GB/T275-1993 "Rolling bearings, shaft and shell matching" , you can select properly size tolerance to determine the correct matching of bearing and shaft or bearing seat.