| Hub bearing is one of the most important components of automobile, the fatigue strength of which has the important meaning to the vehicle's reliability and the security. At present, the domestic bench test of fatigue life of hub bearing still has many problems, such as high cost, long hours, constant load of different operating forms and great dispersion of life, etc, which impact the accuracy and efficiency of the domestic bench test of fatigue life of hub bearing. Based on the problems, the model of DAC407404040 hub bearing was established and the fatigue lives of hub bearing based on multi-bench test load were numerically simulated. And the influence of different operating modes for fatigue life on bench test of hub bearing was analyzed, which provided the basic theory for the research of bearing's failure based on different bench test operating modes. It also raised the efficiency and reduced the cost to a certain extent. The main research contents and achievements are as follows:1. Established the contact mechanics models and carried out the numerical simulation of hub bearing based on multi-operating modes(radial load,axial load and both radial and axial loads). In order to analyze the stress and distortion distribution of hub bearing based on different operating modes, the contact issue of hub bearing was researched. The principles and steps of nonlinear finite element analysis for contact issue were presented briefly and both friction and floating were considered. The approximate boundary condition and reasonable contact parameters were confirmed. The position of the maximum contact stress and stress strain distribution were obtained according to the numerical simulation results which provided the stress strain response for the fatigue life prediction. The results indicated that the maximum stress was on the inner ring and the contact stress area caused by radial force was bigger than the contact stress area caused by axial force. When the equivalent load was equal, the highest value of Mises stress with radial loading was 3392MPa; the higher value of Mises stress with both radial and axial loading was 2431MPa; the lowest value of Mises stress with axial loading was 1960MPa. The stress and strain were partial and changed in gradient. Stress concentration was on the hub bearing, which would be the source of fatigue failure and weaken the fatigue strengthof hub bearings.2. Established the fatigue life prediction model of hub bearing based on multi-operatingmodes and numerically simulated the fatigue lives of hub bearing based on the finite element analysis of hub bearing loading, by using the nominal stress method and linear fatigue damage accumulation theory under different operating modes. The simulation results had shown the location intuitively of the weakness of fatigue strength and destructiveness degree of wheel hub bearing. It also indicated when the equivalent load was equal, it had a relation between the fatigue life and the load formation. The value of fatigue life with the axial load was approximately 3 times than with both radial and axial load simultaneity, 17 times than with the radial load. It was shown nonlinear relations among the value of the stress,life and load.3. In order to validate the rationality and accuracy of the fatigue life numerical simulation, the fatigue life bench test of hub bearing was performed. In the case of axial loading, there was little error between the results of fatigue test and fatigue simulation. But they were in identical magnitude with the average tolerance 18.76% and the locations of the fatigue failure were on the contact area between inner ring and ball.
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