Abstract:

The third generation hub bearing is one of the key components on vehicles, which has a significant impact on the vehicle’s load and steering. For decades, the automobile market in China has been growing continuously, leading to an explosive growth in the production of hub bearings. However, compared with the rapid development of the market, the technical system of the automotive hub bearing industry in China is not fully established, and further in-depth research is needed on the fatigue life analysis of hub bearing. Currently, vehicles are still widely equipped with the third generation hub bearing, and the fatigue life of the hub bearing affects the travel comfort and safety of the vehicles. With the growing requirements, there are higher demands for the fatigue life and reliability of the hub bearing. Therefore, it is necessary to analyze and predict the fatigue life of the hub bearing.

So far, scholars have conducted extensive research on the fatigue life analysis of the third generation hub bearing. The research primarily focused on two aspects: the fatigue life prediction methods and the factors (temperature, rotational speed, and load) influencing fatigue life, while there is relatively scarce research on the influences of lubricants and clearance. In the daily use of hub bearing, inappropriate selection of lubricant viscosity can cause significant friction, heat, and wear on the sliding, rolling, or meshing surfaces of the hub bearing, leading to increased noise and shortened fatigue life. Therefore, the selection of lubricants is crucial. Clearance is an important parameter for hub bearing, and it significantly affects stress distribution, noise, vibration, running accuracy, friction torque, and fatigue life. Reasonable selection of clearance can improve the fatigue life of the hub bearing. Therefore, studying the effects of lubricant types and clearance size on the fatigue life of the hub bearing is of great significance.

Aiming to predict the fatigue life of the third generation hub bearing more accurately, a multi-influence analysis is performed. Based on the Romax modeling and simulation function, the third generation hub bearing simulation model is built. A rotary bending fatigue testing machine is used to conduct the fatigue test, and the errors between the simulation value and the test value are within 7%, demonstrating the reliability of the hub bearing Romax model. The load spectrum of four working conditions is designed by changing the loads, comparing the stress distribution changes of the left and right rows of rolling elements under the four working conditions, and obtaining the law of stress distribution of the rolling elements of the bearings with the load change. Single-factor tests of the bearings are conducted by simulation. An orthogonal test design is employed to analyze the influence weights of the above factors on the fatigue life of the hub bearings. Finally, the change rule of the hub bearing fatigue life affected by four factors (radial load, working temperature, axial working clearance, and lubricant viscosity) is obtained. Meanwhile, the best conditions of the hub bearing are obtained: working temperature within 60 ℃, axial working clearance within -25～-20 μm, lubricant viscosity more than 220 mm2/s. The results of the research may provide references for the improved design of hub bearing.