Vibration Suppression Modification Method Research Of High-speed Gear Transmission Of Pure Electric Vehicle Under Full Working Condition

With the rapid development of electric vehicles,the trend of high-speed drive motor is obvious,and the vibration and noise problems of gear reducer directly connected to the motor are further aggravated due to the increase of input speed.During the driving process of pure electric vehicles,the vibration of the gear reducer will affect the reliability and stability of the whole machine,and the high-frequency noise generated by it will also cause discomfort to the passengers.To improve the working performance of pure electric vehicle gear transmission in the whole working load and speed range,a full working condition system-level tooth surface modification method considering the effects of input torque and speed variation is proposed in this paper.This paper studies the following aspects:(1)Based on the Loaded Tooth Contact Analysis(LTCA),the time-varying meshing stiffness of the gear pair was calculated considering the error and tooth surface modification.According to the geometric relationship and dynamic model of the out-of-line meshing impact,the meshing time and impact force amplitude were calculated,and finally the meshing impact force curve was obtained.The Buckingham semi-empirical formula was used to calculate the friction coefficient,and then the direction function was introduced to obtain the calculation formula of tooth surface friction.(2)The bending-torsion-axis coupling dynamic model of high-speed helical gear transmission was established,and the vibration acceleration in the direction of meshing line was obtained by solving the system dynamic equations.The vibration characteristics of high-speed gear transmission under time-varying meshing stiffness excitation,meshing impact excitation,tooth surface friction excitation,and the combined action of three excitations were analyzed.(3)Based on Tooth Contact Analysis(TCA)and LTCA,the parabolic modification of tooth profile and axial was carried out.Combined with genetic algorithm,the modification coefficient of tooth profile and axial was optimized,and the optimal modification scheme of high-speed gear transmission under multi-torque and full-speed domain was obtained,and compared with the modification scheme under specific torque and specific speed.(4)The dynamic model of two-stage helical gear transmission system of pure electric vehicle was established.According to the output characteristics of the motor,the working condition of the transmission system is determined.The system-level vibration evaluation index is proposed,and the vibration suppression effect of the system is analyzed when only the single-stage gear pair was modified and the two-stage gear pair was modified together.The influence of torque and speed on the modification scheme in two-stage gear transmission was discussed.The results show that tooth surface modification considering the influence of working conditions has better global applicability.