Design And Optimization Of High-power Transmission Housing

As one of the key parts of the high-power transmission,the housing is a typical complex thin-walled shell part,and the housing is subjected to complex forces during the working process of the high-power transmission,so it is difficult to design the housing.The traditional housing design method is mainly based on the designer’s experience and referring to the appearance of similar transmission housings.In order to ensure the reliability and safety of the housing,the safety factor of the housing is usually too high,and the design cycle of the housing is long,and the design efficiency is low.Therefore,in order to improve the design efficiency and the overall performance of the housing,this paper takes a high-power transmission housing as the research object,and combines the design experience of the housing with the finite element method to design housing’s structure.The main research work and results are as follows:(1)This paper summarizes the traditional design experience of the transmission housing and the specific methods to be followed when the housing is analyzed by finite element method to evaluate the overall performance.The specific design requirements of the high-power transmission housing studied in this paper are put forward.According to the traditional housing design experience,the overall scheme of the high-power transmission housing is designed,and the initial three-dimensional model of the housing without stiffeners is established.(2)The finite element analysis of the initial design of the housing,mainly including static analysis and modal analysis,is carried out,which lays the foundation for the subsequent topology optimization and size optimization.In the static analysis,the stress and deformation cloud charts of the housing in the first two gears are calculated,and the static performance of the housing is evaluated according to the results.The strength and rigidity of the housing are redundant,but the weight is too large.In the modal analysis,the first ten modes of the transmission housing are calculated,and the dynamic performance of the housing is evaluated according to the results.The second natural frequency of the housing is close to the natural frequency of the engine,which may cause resonance.(3)The topology optimization analysis of the initial design housing is carried out to find the optimal force transmission path and design the internal stiffeners.Taking the maximization of the stiffness of the housing as the optimization goal,the topology optimization analysis of the housing structure based on the variable density method is carried out.According to the optimization results and traditional housing design method,the housing is initially improved,mainly including the wall thickness of the shell is reduced and reasonable stiffeners are designed.Compared with the initial housing,the weight of the improved housing is reduced by 20.9%,and its stiffness and strength also meet the design requirements.However,the second natural frequency of the housing is close to the excitation frequency of the engine,which will cause the resonance of the housing.(4)The size optimization of the housing which is improved by topology optimization is carried out to determine the size of the key parts of the housing.Under the premise of satisfying the requirements of housing stiffness,strength,and frequency,the multi-objective optimization of the housing is carried out with the optimization objectives of maximizing the stiffness and minimizing the weight of the housing.During the optimization process,the sensitivity analysis of each design variable of the housing is carried out.The influence of the design variable of the housing on the design index of the housing is explored,and the response surface of the design variable corresponding to the design index is established.According to the optimization results,the housing structure is improved again.Compared with the housing which is improved after topology optimization,the weight of the housing is reduced by 3%.Its rigidity and strength meet the design requirements.The second natural frequency of the housing reaches 281.67 Hz,which is far from the excitation frequency.The dynamic performance of the housing is good.