Vehicle Wheel Bearing Fatigue Life Analysis

Wheel bearing, one of the key parts of automobile, is vital to the vehicle’s loadcapacity and security and thus the study on its fatigue life and reliability is of greattheoretical significance and practical value. The common bearing life predictions mainlyrely on field trials and data collection. Backed up by some mechanical simulation softwares, the prediction of fatigue life under multiple loading conditions and the analysis ofthe effects of different conditions on the fatigue life will provide a theoretical basis for theresearch on the failure of wheel bearings in different bench experiments. The mainresearch work includes:(1). Carry out the stress numerical simulation of wheel bearing after establishing awheel bearing contact mechanics finite element model in ABAQUS environment. Theresults show that the wheel bearing stress is mainly distributed in a very small contact areawith the greater stress levels, wherein the level of stress of the outer ring is lower than thatof the inner ring. The maximum stress occurring in the inner ring is prone to produce microcracks on the contact surface because of the stress strain, which is the origin of fatigue.Accordingly, as the fatigue strength and the reliability are reduced, the working life of thewheel bearing is shortened.(2).The theory of vehicle wheel wheel bearing life and the vehicle wheel bearingsmechanical model give rise to the estimation methods of bearing working life. The data ofestimation signify that the surface roughness of the parts will seriously affect the workinglife of wheel bearing, so polishing the inner ring with more advanced process is aneffective means to improve its reliability.(3). Establish the reliability expression by using the Weibull distribution as thedistribution function of the bearing reliability. Estimate Weibull parameters with the use ofBayesian theory and beta distribution as prior distribution. Conduct reliability experimentby taking the wheel bearings of a manufacturer as samples. The results of the experimentverify that the inner ring is a less reliable component. The improvement of its reliability requires more advanced hardening process or structural steel of higher strength and wearresistance.The thesis presents scientific analyses in terms of wheel bearing’s working life,reliability, stress strain as well as the causes that result in the fatigue. It aims at the researchon the improvement of the life and reliability of wheel bearings which then will provideeffective protection for the driving safety.