Analysis And Optimization Of Vibration And Noise Of An Electric Vehicle Reducer

In recent years,with the strong support of national policies,the electric vehicle industry has entered a period of rapid development.In addition to emerging automotive companies,traditional automobile companies have not given up entering the electric vehicle field.Electric vehicles are very different from traditional fuel vehicles.Electric vehicles often use a reducer to replace the transmission and use a motor as a power source.The powertrain of a car is usually one of the main sources of automobile noise.The noise of the motor is much smaller than that of the engine.The reducer is the main component of the electric vehicle transmission system.Without the sound of the engine,the noise of the reducer will become more obvious.It is also a new challenge.The NVH performance of the reducer will affect the NVH performance of the entire vehicle,which will affect the passenger comfort.Therefore,it is of great significance to study the vibration and noise of the electric vehicle reducer.Based on a new energy company's reducer development project,this paper conducts an in-depth study of the reducer vibration and noise,and mainly completes the following work.(1)The finite element model of the reducer casing and the differential casing is established,and The dynamic model of the gear system is established according to the parameters of the gear system of the reducer.The finite element model is imported into the gear system dynamics model to obtain the reducer system dynamics model.The model analyzes the static transmission error of the reducer.The static transmission error is used as the excitation to calculate the dynamic response of the bearing.The dynamic force of the bearing is obtained to lay the foundation for the vibration response analysis.(2)The modal analysis of the reducer shell finite element model is performed to obtain the natural frequency and mode shape of the restraint mode of the reducer shell.The bearing dynamic force is used as the excitation of vibration response analysis to obtain the vibration response of the reducer shell.The acoustic boundary element model of the reducer shell is established.The vibration response data is mapped to the boundary element model as a boundary condition for radiated noise analysis to obtain radiated noise.Analyze the noise simulation data to extract the frequency of the location where the sound pressure amplitude is large.(3)A noise test was performed on the reducer based on the existing NVH test rig to verify the accuracy of the vibration and noise simulation model.Select the mode near the frequency according to the frequency corresponding to the larger location of the sound pressure amplitude.The modal strain energy distribution was analyzed.Based on the modal strain energy distribution,the effects of stiffeners,shell thickening,and material parameters on the radiation efficiency of the reducer were studied.Based on the study of radiation efficiency,an optimization plan for the reducer housing was proposed.