Strength And Fatigue Life Analysis Of Heavy Duty’s Main Reducer Gear

With the rapid development of transportation industry in our country,heavy duty vehicle has been widely used in many field, so many companies and users put higher requirements for its transmission system. As the important part of the transmission system, the main speed reducer can reduce speed and increase its torque. In addition, when the engine longitudinal, it can change the rotation direction of torque. In recent years, some scholars have made some relegated researches. According to their researches about the failure condition of main reducers, the failure of many main reducers are caused by fatigue. So it has important practical significance to study and predict the fatigue life of the main speed reducer.In this paper, the main speed reducers of heavy duty vehicle is taken as the study object. First of all, its structure, working principle, failure forms and preventive measures are introduced in detail. Secondly, it introduce some important fatigue theory, through these fatigue prediction method, nominal stress method and Miner fatigue cumulative damage theory to predict the fatigue life of main speed reducer are ensured to be used in this paper.Solidworks is used to establish a geometric model and put them together, then make interference analysis, The static analysis of main speed reducer is carried out in the finite element analysis software Workbench. Using the seamless connection between Solidworks and Workbench, the 3D model can be imported to Workbench. When completing the simplification of geometric model, the mesh of geometric model is carried on and the finite element model is established.After that, the nonlinear settings is completed. In the end,according to the working conditions of the main reducer,the certain amount of torque is applied on the main speed reducer-then the contact stress of theory can be obtained. Through the comparison between the value from finite element software and the theoretical value, it can be fined that both values are unite basically. Thus it proves the correctness of finite element method. Through the analysis of simulation result, It can be seen that the equivalent stress from contact area between the driving gear and the driven gear have a maximum value. So this site is the most prone to fatigue damage.According to the results from the finite element analysis,fatigue life analysis in the fatigue analysis module of the Workbench is used,fatigue life, dangerous parts damage, safety coefficient and other related parameters are obtained. Thus the results have a protective effect on the main speed reducer in a certain extent.