The inner part of the bearing is generally composed of inner ring, outer ring, rolling element and cage - usually called four parts.

For sealed bearings, add lubricant and sealing ring (or dust cover) - also known as six pieces.

When the bearing is working (rotating at a certain speed), it has the ability to bear radial load or axial load.

When the bearing rotates at a certain speed, there will be radial or axial runout.

According to the working conditions of bearings, different types of bearings can be selected to better play the function of bearings and extend the service life of bearings. The factors to be considered in selecting bearings are: