The bearing and the shaft or bearing housing with the purpose to the inside, the outer ring firmly fix on the shaft or bearing housing, mutual non-harmful sliding. With the surface of the sliding, it will produce abnormal heat and wear, as a result of the wear powder into the bearing and cause early damage and vibration, and other ills, the bearing can not fully perform its functions. In addition, bearing with the impact of the bearing radial clearance, the radial clearance is not only related to the operation of precision bearings and also affected its life.

Rolling of the bearings is the standard components, so the co-ordination with the relevant parts inside the hole and outside diameter reference holes and the reference axis, respectively, do not have to cope with the label. Decided to support the main problem is the load bearing inner and outer rings of the bear state.

In general, the size, load, vibration, high speed or high operating temperature should be selected tight for some with, and often demolition or swim rings loose with.