Deep groove ball bearings in general a pair of rings from a group of Cage composed of a set of balls. Its structure is simple and easy to use, is the production of the most common the most widely used for a class of bearings. The type of bearings is mainly used to bear radial load, but it can withstand a certain amount of any one of the axial load direction. When a certain extent, increase the oil-gap radial bearings, such bearings with angular contact ball bearing nature, also can bear a larger axial load. Deep groove ball bearings mounted on a shaft, the shell enable the axis of axial displacement or to limit the scope of the axial bearing. At the same time, when the shell-hole and shaft (or the outer ring of the inner circle) are tilted relative, (no more than 8-16, in accordance with clearance determined) can still work properly. Given the existence of tilt, they are bound to reduce the bearing life.