What are the differences between first-generation and second-generation bearings?

What are the differences between first-generation and second-generation bearings?

 

The main differences between first-generation and second-generation bearings lie in their structural design, installation methods, and performance characteristics, as detailed below:

 

Structural Design: First-generation wheel Hub Bearings are double-row Angular Contact Ball Bearings or double-row Tapered Roller Bearings with an integral outer ring and a back-to-back inner ring. The bearing is independent of the steering knuckle and wheel hub. Second-generation wheel hub bearings integrate the wheel hub into the first-generation design, and the outer ring has a flange, making the structure relatively more complex.

 

Installation Method: First-generation bearings require pressing the inner ring onto the wheel hub and the outer ring into the steering knuckle during online assembly. This assembly process is complex and requires high levels of equipment and process control. Second-generation wheel hub bearings, with their flanged outer ring, can be directly bolted to the suspension (inner ring rotating type) or installed onto the brake disc and wheel rim (outer ring rotating type), eliminating the need for pressing into the wheel hub. However, they still require an interference fit with the steering knuckle, although the assembly precision is only slightly higher than the first generation.

 

Performance Characteristics: First-generation bearings suffered from significant performance deviations after press-fitting due to the difficulty in precisely controlling the installation process, resulting in overall lower performance. While second-generation hub bearings showed some improvement in assembly, they still suffered from poor performance, such as under high loads and complex operating conditions compared to later-developed third-generation bearings.