Study On Bending And Torsional Vibrations Of Traction Motor Rotor System For EMUs

With the rapid increase in the operating speed of EMUs,the safety,reliability and smoothness of traction motors have attracted more and more attention.Traction motor is the core component of electromechanical energy conversion in the mechanical traction drive system of high-speed EMUs.The vibration problem is not only related to the smooth operation of the motor itself,but also directly affects the reliability and life of the motor suspension parts,and even relates to the high-speed EMUs driving safety.Therefore,it is important to study the rotor dynamics characteristics of traction motors.The purpose of this paper is to study the flexural and torsional vibrations of the rotor of an asynchronous traction motor used in EMUs under radial and torsional loads,in order to lay a good foundation for a thorough and in-depth study of the dynamic characteristics of traction motors,and to design the traction motors.Manufacturing and troubleshooting provide effective theoretical support.This article first elaborates the background,purpose and significance of the research.The current research status of the rotor load of the motor is briefly introduced,and the research on the bending and torsional vibration of the motor is reviewed.According to the operating principle of the asynchronous motor,first analyze and calculate the load operating data and electromagnetic parameters of the traction motor.Then combined with the characteristics of various loads that the rotor of the traction motor bears,the radial load and torsional load model of the rotor are established.The key is to establish the unbalanced magnetic tension model of the asynchronous motor during load operation.Based on the finite element method,the natural vibration characteristics of the traction motor rotor system are analyzed in the ANSYS platform.The natural frequency,vibration mode and critical rotation speed of the traction motor rotor are obtained.Then,according to the bending vibration of the traction motor rotor system,a variety of rotor radial loads are considered and a radial vibration model of the traction motor rotor is established.The radial vibration characteristics of the traction motor rotor under various radial loads were analyzed.The effects of radial load and main rotor parameters on the radial vibration characteristics of the rotor and the unbalanced magnetic tension vibration were obtained.The traction motor rotor is discretized,and the rotor is simplified as a disk shaft system consisting of a rigid disc and an elastic shaft segment.Based on this,an undamped torsional vibration model of the traction motor rotor is established,and the natural frequency and mode shape of the torsional vibration of the rotor are analyzed.Finally,the coupled bending and torsion vibration model of the traction motor rotor system is established.The effects ofvarious radial and torsional loads on the bending and torsional vibration response of the rotor are studied,and the running state of the traction motor under the action of the radial and torsional loads of the rotor is simulated.It is concluded that the radial load will cause torsional vibration at multiple frequencies in the torsional vibration of the rotor,and the torsional load will also cause bending vibration at multiple frequencies in the bending vibration of the rotor.The frequency and amplitude of bending or torsional vibration caused by the rotor load through the bending-torsion coupling are closely related to the characteristics of the rotor load.