Dynamic Investigation of Motor Bearing in a Locomotive under Excitation from High-Order Wheel Polygonization

Bearing is a basic component of the rotational mechanical system and its dynamic performance has a direct effect on the stability and reliability of the mechanical product, such as the railway locomotive. The wheel polygonization is a common wear of a locomotive in the running process. The more drastic vibration environment of the locomotive due to the intensified wheel-rail interaction will make the working condition of the motor bearing more complicated which is likely to cause bearing failures, such as pitting corrosion, spalling, plastic deformation, and cage fracture. In this paper, a locomotive-track coupled dynamics model with traction motor, axle box bearing, and gear transmissions is established where the bearing subsystem supporting the motor rotor and the pinion gear is considered in detailed so that the skidding characteristics, the nonlinear contact forces between the components of the bearing and the corresponding friction forces are included. The results indicate that the intense wheel-rail interaction caused by the high-order wheel polygonization will affect the dynamic characteristics of the motor bearing significantly. Furthermore, this model can assess the skidding phenomenon of the motor bearing under vehicle vibration of a locomotive effectively.