1.Early stage: Early automotive technology is relatively simple, and the wheel bearings of cars are mostly single-row tapered roller bearings or pairs of ball bearings
2.The first generation of hub bearing units: With the development of technology, the first generation of hub bearing units consisting of double row angular contact bearings appeared. Its structure is simple, the cost is low, compared with the early single-row tapered roller bearings or paired ball bearings, the bearing performance is improved to a certain extent
3.Second generation hub bearing unit: Based on the first generation, the second generation hub bearing unit adds a flange for fixing the bearing on the outer raceway. Through this flange, the bearing can be simply sheathing to the axle and fixed with nuts, making the maintenance of the car easy, while also improving the bearing capacity and service life
4.The third generation of hub bearing units: This generation of hub bearing units adopts the design of bearing units and anti-lock brake system (ABS)This structure can better adapt to the situation of high speed and heavy load, improve the safety and stability of the car