Analysis And Optimization Of Transmission Efficiency Considering NVH Performance Of Reducer

The transmission efficiency of the electric vehicle reducer has an important influence on the range of the electric vehicle.In order to improve the range of the electric vehicle,it is an important means to change the gear parameters of the reducer,but there are problems that the change of the gear parameters will also affect the NVH performance of the reducer.In this paper,a method of optimal design and analysis of electric vehicle reducer considering NVH performance is proposed,which can effectively balance the contradiction between transmission efficiency and NVH performance improvement.The main work is as follows:Firstly,the key factors affecting the transmission efficiency of the reducer are studied,and the calculation models of the power loss of the gear pair,the friction power loss of the gear and bearing,and the friction power loss of the oil seal are summarized.The transmission efficiency analysis model of reducer is established by setting up the analysis model of power loss of gear oil churning and friction power loss,and the transmission efficiency test of reducer assembly is used to verify the accuracy of the simulation model,which provides a new transmission efficiency simulation calculation method for transmission efficiency analysis.Secondly,the Romax software has been utilized to build the NVH simulation analysis model of the reducer,and the model is designed for studying the influence of power loss factors on the NVH performance of the reducer.To ensure the constructed NVH performance simulation analysis model,a modal test was used to verify the modal information of the reducer housing in the model.Then,the orthogonal experiment method was adopted to study the factors of churning power loss of the reducer.The main influencing factors of the churning power loss of the gear are rotation speed,gear oil kinematic viscosity,oil immersion depth,number of teeth,tooth width,gear helix angle and pressure angle.Through the single variable power loss analysis and research on the main influencing factors of gear oil churning power loss,influence of various factors on the oil churning power loss and friction power loss of the reducer have been found:Such as the oil churning power loss increased with the speed,the depth of oil immersion,The number of teeth and tooth width increasing;with the decrease of lubricating oil temperature,helix angle and pressure angle,the loss of oil churning power is growing.The friction power loss declines with the increased of pressure angle and tooth width.The helix angle and gear friction power loss show a trend of decreasing first and then increasing within a certain range.In terms of NVH,the influence factors of the gear transmission error of the reducer are determined by the orthogonal experiment method by analyzing tooth width,helix angle and pressure angle.Transmission error analysis of a single variable was analyzed and it is concluded that the gear transmission error gets increase when the gear helix angle and pressure angle increasing,but becomes decrease with the tooth width increasing.Finally,based on the analysis of the influencing factors of transmission efficiency and transmission error,an optimization plan was formulated.Through simulation analysis of different schemes,the optimization plan was finally determined to modify the tooth width to 27mm,the helix angle to 32°,and the pressure angle to 21.5°.The transmission efficiency and NVH performance of the reducer are calculated and verified,and the maximum transmission efficiency is increased by 2.62%.The bearing force is reduced,the front bearing is reduced by about 10N on average,the rear bearing is reduced by about 6N on average,and the vibration peak of the reducer shell There is a 10m/s~2 drop,and the sound pressure at the field point is reduced accordingly,ensuring the NVH performance of the reducer.