The first generation wheel hub bearing unit: It is composed of double-row angular contact bearings, with a relatively simple structure, which improves the performance and reliability of the bearing to a certain extent. It can better withstand axial and radial loads and provide stable support for the rotation of the wheel hub. In some early economy cars, the first generation of wheel hub bearing units have been widely used to meet the basic driving needs of vehicles.

The second generation wheel hub bearing unit: A flange for fixing the bearing is added to the outer raceway, making the bearing installation more convenient. Just simply put it on the axle and fix it with a nut. This design greatly simplifies the car maintenance process and reduces the difficulty and cost of maintenance. At the same time, its structural design is further optimized, and compared with the first generation, it has a certain improvement in load-bearing capacity and stability. In some mid-range cars, the second generation wheel hub bearing unit has become the mainstream configuration.

The third generation wheel hub bearing unit: It works closely with the anti-lock brake system (ABS) to achieve a higher level of integration. The wheel hub unit is designed with an inner flange and an outer flange. The inner flange is fixed to the drive shaft by bolts, and the outer flange installs the entire bearing as a whole. This design not only improves the installation accuracy and reliability of the bearing, but also works better with the vehicle's electronic control system, improving the safety and handling of the vehicle. At present, the third-generation wheel hub bearing unit has been widely used in various types of vehicles and has become a mainstream product in the market.

The fourth-generation wheel hub bearing unit: innovatively combines the constant velocity joint and the bearing into one, effectively solving the problem of increased wheel hub size and weight due to the integrated structure of the wheel hub and the constant velocity joint in the existing technology. The fourth-generation wheel hub bearing unit pays more attention to lightweight and miniaturization in design, and further improves the performance and reliability of the bearing by optimizing the structure and adopting new materials. Although its large-scale application is still in the process of advancement, as the technology continues to mature, it is expected to be widely used in various types of vehicles in the future, bringing new changes to the automotive industry.