The rolling bearing developed on the basis of sliding bearing, its working principle is to replace sliding friction by rolling friction, generally consists of two rings, a group of rolling body and a cage composed of a strong versatility, standardization, high degree of serialization of the mechanical foundation parts.Due to the different working conditions of various machines, different requirements have been put forward for the load capacity, structure and performance of rolling bearings.For this reason, rolling bearings need to have a variety of structures.However, the most basic structure consists of an inner ring, an outer ring, a rolling body, and a cage.

The functions of various parts in the bearing are as follows:

For centripetal bearings, the inner ring is usually in close coordination with the shaft and operates with the shaft, while the outer ring is usually in transition coordination with the bearing seat or the hole in the mechanical housing to play a supporting role.However, in some cases, there are also outer ring operation, the inner ring fixed supporting role or inner ring, outer ring are running at the same time.For thrust bearing, it is called the shaft ring that works closely with the shaft and moves with it, and it is called the seat ring that works with the bearing seat or the hole in the mechanical housing and plays a supporting role.The rolling body (steel ball, roller or needle) is usually arranged evenly between two rings in the bearing by means of the cage for rolling movement. Its shape, size and quantity directly affect the bearing's load capacity and performance.The cage can not only separate the rolling body evenly, but also guide the rolling body to rotate and improve the internal lubrication of the bearing.