According to the load acting on the bearing relative to the rotation of the ring, there are three types of loads borne by the rolling bearing ring: local load, cyclic load, and swing load. Generally, tight fits are used for cyclic loads (rotating loads) and swing loads; unless there are special requirements for use, local loads are generally not suitable for tight fits. When the rolling bearing ring is subjected to a dynamic load and a heavy load, both the inner and outer rings should adopt an interference fit, but sometimes the outer ring can be a little looser and should be able to move axially in the bearing housing hole; when When the bearing ring is subjected to swing load and the load is light, a slightly looser fit than a tight fit can be used.

Load 

The amount of interference between the bearing ring and the shaft or housing hole depends on the size of the load. When the load is heavier, a larger interference amount is used; when the load is lighter, a smaller interference amount is used. Generally, when the radial load P is less than 0.07C, it is a light load, when P is greater than 0.07C but equal to or less than 0. When 15C, it is a normal load, and when P is greater than 0. When 15C, it is a heavy load (C is the rated dynamic load of the bearing).

Operating temperature 

When the bearing is running, the temperature of the ferrule is often higher than the temperature of adjacent parts. Therefore, the inner ring of the bearing may become loose with the shaft due to thermal expansion, and the outer ring may affect the axial movement of the bearing in the housing hole due to thermal expansion. When choosing a fit, the temperature difference and expansion and contraction of the bearing assembly part should be taken into consideration. When the temperature difference is large, the fit interference between the shaft and the inner ring should be larger.

Rotation accuracy

When high rotation accuracy is required for bearings, clearance fit should be avoided in order to eliminate the effects of elastic deformation and vibration.

Structure and material of bearing housing hole

For the formal shell hole, interference fit should not be used when matching with the bearing outer ring, nor should the outer ring rotate in the shell hole. For bearings installed in thin-walled housing bores, light metal housing bores, or hollow shafts, a tighter fit should be used than in thick-walled housing bores, cast iron housing bores, or solid shafts.