The Non-linear Contact And Fatigue Life Analysis Of Differential Gear Of Loader

The fatigue life prediction of differential gear in drive axle of loader has great significance to the structural design of the driver axle, because of the complicated structure and force of the loader, the prediction and actual life of the gap was large. Taking the differential gear of ZL50 wheel loader as the research object, the paper, using the probability statistics, the non-linear contact finite element analysis and the fatigue theory, in-depth and systematically studied the nonlinear contact finite element analysis and fatigue life prediction method of the differential gear, and analyzed the impact of fatigue life prediction which the load spectrum, the gear solid model and the uncertainty of material parameters of mechanical properties produced.By analyzing the wheel loader of the actual working conditions, according the engine and the torque converter characteristic curves of match together, the paper determined the maximum working load of the loader. On this basis, based on the normal distribution function with loader loads and the principle of classification with the load program spectrum, the paper used"3σ"theorem and probability statistics to write the torque program spectrum block of the differential gear.Based on the profile curve and the tooth root transition curve equation of the differential gear, the paper utilized the capability of Pro/E parametric modeling to create a precise differential gear solid model for the finite element analysis and the fatigue life analysis.Adopting the non-linear contact finite element method to numerically simulate the whole contact process in gear for the differential gears, the paper discussed the influence of the non-linear calculation convergence and the accuracy of the results for cell types and mesh quality, constraints, and contact with real constant set, and created the stress spectrum for fatigue life analysis.For the fatigue life analysis with the finite element actual stress spectrum, based on the material S-N fatigue curves, the paper respectively discussed the influence of the part fatigue life with stress concentration and size effect and surface conditions, and founded the equation of the part S-N fatigue curves, and explored the scope of the critical fatigue damage of steel materials DC R; the paper respectively estimated the bending fatigue life of the differential gear using the modified Miner theory by the Elementary Miner rule and the Haibach rule, received the middle reliability life scope of half axle gear, and explored the impact of load statistical analysis on the fatigue life.The results showed that under the 3D virtual environment of the finite element, the dynamics analysis had enough precision when using the gear solid model with the exact surface equation of the gear tooth. When the loader loads obeyed the normal distribution and the differential gear obeyed symmetrical cyclic loading, in the whole contact period of a pair of tooth, we can get the stress spectrum of gear weaknesses, and predicted the gear's fatigue life using the fatigue cumulative damage theory. In actual working environment, the test showed that the prediction results were consistent with the actual situation, which verified the credibility of the research methods. At the same time, the paper provided a new method and theory for the fatigue life prediction of the gear.