Effect of Different Combined Excitation on the Vibration Characteristics of Locomotive Gear Transmission

With the continuous improvement of locomotive operating speed, increasing axle load and increasing traction power, the dynamic excitation of wheel-rail interface and gear pair interface have become more and more intense, directly affecting the operational reliability or even safety of the locomotive or the train. Based on the traditional rotor dynamics and the classical vehicle-track coupled dynamics, a locomotive-track coupled spatial dynamics model is established, in which the dynamic effects from drive system are considered. Under three different combinations of excitation, namely constant mesh stiffness, time-varying mesh stiffness and track geometrical irregularity, the vibration responses of the gear transmission are simulated during the uniform and accelerated operation of the locomotive. By comparing the difference of vibration response, mesh force and dynamic transmission errors of gear pair of traction motor under different combinations of excitation, the influence of different excitation on the vibration characteristics of gear transmission is explored. The following conclusions are drawn: 1) The time-varying mesh stiffness directly affects the vertical and longitudinal vibration of the traction motor. 2) The influence of time-varying mesh stiffness and track geometrical irregularity varies at different speed stages of locomotives. 3) During the acceleration process of the locomotive, resonance phenomenon of the traction motor and gear pair can be caused at a certain speed when considering time-varying mesh stiffness. The conclusions obtained will provide certain reference significance for the selection of design parameters, evaluation of dynamic characteristics, and life prediction of locomotive drive system.