Study On Dynamic Characteristics And Optimization Of High Speed Train Body Suspension Traction Drive System

With the continuous improvement of train speed and the continuous increasing of running mileage,it has brought great convenience to people’s travel and regional economic development,but at the same time,problems about the dynamics of vehicle system also emerge.Therefore,how to improve the operation performance of high-speed trains and the stability of vehicle system has become the focus of scholars at home and abroad.Among many problems,the research on the traction drive system is top priority,because the traction drive system,as the power source and force transmission component of the train,will produce a large dynamic response and have a non-negligible impact on the vehicle system.The dynamic characteristics of the traction drive system are also different.Among them,the body suspension traction drive system has an irreplaceable role due to its unique advantages,however,few studies have been conducted and the body suspension traction drive system has not been analyzed as a whole in conjunction with the vehicle system.In order to improve the operational performance of vehicle systems,this paper establishes a high-speed train dynamics model using body suspension traction drive system,and carries out research on its dynamic characteristics and the optimization of suspension parameters of the traction drive system,mainly as follows:(1)The influence of body suspension traction drive system on the dynamic characteristics of high-speed train is studied.The results show that the traction drive system has different effects on vehicle safety and stability,which reduces the nonlinear critical speed and lateral riding index,and increases the derailment safety index,wheel-rail force and vertical riding index.In addition,except for the lateral riding index,the other indicators all become larger with the improvement of the speed.In terms of vibration acceleration,for the frame,the traction drive system increases its lateral and vertical acceleration,and for the car body,the drive system reduces its lateral acceleration and increases the vertical acceleration.In addition,the driving force of the motor has little influence on the gearbox and the motor,but it will lead to the increase of the amplitude of the gear engagement frequency,and the automatic vibration frequency of the motor is reflected in the frequency domain diagram of the car body.(2)The vibration characteristics of the suspension points of motor,gear box and car body motor are studied,as well as the influence of the suspension parameters of traction drive system on itself and car body are studied.It is found that the vibration response of the motor,gear box and suspension points of car body motor will increase with the increase of speed.Comprehensive consideration,it is suggested that the transverse stiffness of single spring of motor suspension is 100～300k N/m and the vertical stiffness is 200～400k N/m;the single damping of transverse and vertical damping is about 10 k Ns/m;the transverse span of spring is1.5m～1.8m;the longitudinal stiffness of reaction rod is above 20000 k N/m.(3)Based on the value range of the parameters obtained in the previous part,the multi-objective optimization research was conducted for the 6 suspension parameters of the traction drive system.It can be seen from the results that the optimized parameters lead to different degrees of improvement in each index.Among them,the maximum and minimum optimization amplitude of the design variables are 44.981% and 3%,respectively,and the maximum and minimum optimization amplitude of the optimization target are 79.973% and0.764%,respectively.In addition,the addition of motor suspension damping has a significant suppression effect on both vibration acceleration and displacement of the motor.