Improved Dynamics Model of Locomotive Traction Motor with Elasticity of Rotor Shaft and Supporting Bearings

Abstract

The locomotive traction motor is described as a rotor-bearing system coupling the kinetic equations of the traction shaft and its support bearings with the determination of their elastic deformations in this study. Under the effect of excitations induced by the dynamic rotor eccentric distance and time-varying mesh stiffness, the elastic structure deformations of the shaft and support bearings are formulated in the vibration environment of the locomotive. In addition, the nonlinear contact forces between the components of the rolling bearing, the lubricating oil film, and radial clearance are comprehensively considered in this study. The results indicate that the elastic deformations of the shaft and bearings can change the dynamic responses of the traction motor and its support bearings. There are large differences between the ranges of the rotor motion calculated by the rigid and the flexible traction motor models when the intensified wheel-rail interaction is considered. With the increase of the rotor eccentricity, the results underscore the role of the elasticity of traction shaft and support bearings in dynamic researches of the traction motor. The critical value of the initial eccentric distance for the rub-impact phenomenon decreases from 1.23 mm to 1.15 mm considering the flexible effect of the shaft and bearings. This dynamics model of the traction motor can provide more accurate and reasonable simulation results for correlational dynamic researches.