Study On Vibration And Gear Modification Of Planetary Transmission System Of Electric Vehicle Transmission

With the development of electric vehicle industry,the issue of whether electric vehicles need to carry gearbox is concerned in relevant fields.Relevant research shows that the economy and power performance of electric vehicles will be improved by matching multi-speed gearboxes.At the same time,the vibration and noise quality of electric vehicle transmission is concerned by people from the outside world,and the vibration and noise reduction of electric vehicle transmission has naturally become a key technology.In this paper,a planetary transmission system of electric vehicle transmission is taken as the research object.The vibration characteristics of the planetary transmission system are studied based on the combination of theory and simulation.The transmission error of the system gear transmission is reduced by gear modification,and the stability of the system transmission is improved,and the vibration of the system in the working process is reduced.The main contents of this paper are as follows :Firstly,the structure and basic working principle of the planetary transmission system are analyzed.The finite element virtual prototype model of the planetary transmission system is established by using the transmission professional analysis software Romax Designer,and the static simulation of the model is carried out.Considering the force characteristics of the system in the actual working process,the bending-torsion dynamic model is applied to analyze the dynamic characteristics of the transmission planetary transmission system,and the dynamic differential equation of the transmission system is derived.At the same time,according to the principle of vibration and gear meshing transmission,the main vibration excitation of the automatic transmission planetary transmission system are analyzed and simulated.Secondly,the finite element modal analysis of planetary transmission system is carried out by using Lansos method,and the first ten natural frequencies and vibration modes of the system are observed.At the same time,the gear meshing characteristic frequency is calculated according to the characteristics of planetary gear transmission,and compared with the natural frequency of the system.The first-order harmonic of the linear transfer error of each gear pair is used as the vibration excitation of the system,and the dynamic force of the bearing is used as the amplitude.The vibration response of the planetary transmission system in x,y and z directions is obtained by simulation.With the dynamic acceleration as the amplitude,the dynamic response waterfall nephogram of the input shaft and the output shaft is obtained by simulation.At the same time,the working deformation of the system at a certain time is analyzed,and the input and output bearings are used as two nodes to analyze the frequency response function of the system.Finally,in view of the large vibration response of the transmission planetary transmission system bearing in the x direction,a method to reduce its vibration by modifying the system gear is proposed.According to the analysis results of the contact spot of the system gear and the meshing misalignment,the appropriate modification method is determined,and the influence of the modification amount on the main indexes is analyzed.Combined with the software genetic optimization algorithm module,the appropriate modification amount is determined.After the modification of the gear,it is found that the gear transmission planetary transmission system has significantly improved the partial load of the gear transmission compared with that before the modification,and the meshing transmission error of each gear and the vibration response of the bearing are reduced,which provides a certain reference for the vibration and noise reduction of the planetary transmission system.