The most common use of car wheel bearings was single-row tapered roller or ball bearings in pairs. With the development of technology, car hub units have been widely used in cars. The use range and usage of wheel hub bearing units are increasing day by day, and it has developed to the third generation: the first generation is composed of double row angular contact bearings. The second generation has a flange for fixing the bearing on the outer raceway, and the bearing can be simply sleeved on the axle and fixed with a nut. Makes the maintenance of the car easier. The third-generation wheel hub bearing unit uses the bearing unit to cooperate with the anti-lock brake system. The hub unit is designed with an inner flange and an outer flange, the inner flange is bolted to the drive shaft, and the outer flange installs the entire bearing together