Acquisition method of dynamic load of high-speed train gearbox bearing based on bench simulation model

To acquire the dynamic loads of gearbox bearings for high-speed trains under the operational vibration environment, a bench simulation model for the gearbox of a high-speed train was built using the dynamics software SIMPACK. The multi-point coherent random vibration control algorithm based on the spectrum correction was used to reproduce the multi-point coherent line excitation on the gearbox by applying the longitudinal, lateral, and vertical measured acceleration power spectra of the axle box with a virtual exciter. Moreover, for the cylindrical roller bearing on the motor side of the gearbox input shaft, the bench simulation model was employed to obtain its radial load and center trajectory and the contact load between the roller and outer ring raceway under the operational vibration environment. Analysis results indicate that by the control algorithm based on the spectrum correction, when the optimization speed index is 0.3, the relative error between the simulated and measured acceleration power spectra of the axle box tends to be stable after 10 iterations, and the maximum relative error is less than 10%. Under different input torques of motors, the dynamic loads of gearbox bearings with and without line excitation show that the input torque of motors determines the mean of the dynamic loads, and line excitation is the main reason for the fluctuation in the dynamic loads. The spectrum analysis reveals that the line excitation increases the energy of the radial load of the bearing in the middle and low frequency bands and gear meshing frequency. Meanwhile, the line excitation increases the contact load between the roller and the outer ring raceway, but the contact area and mean of the contact load have no significant change. When there is no line excitation, the trajectory of the bearing center vibrates along the pressure angle of gears, and the angle with the vertical axis is 26°. The line excitation makes the fluctuation range of the trajectory of the bearing center larger and more random, and no obvious characteristic is shown in any direction. So, the input torque of motors and line excitation are the main sources of the dynamic loads of gearbox bearings for high-speed trains, and the bench simulation model can provide a valuable reference for the dynamic response evaluation and load spectrum establishment of gearbox bearings for high-speed trains. © 2022, Editorial Department of Journal of Traffic and Transportation Engineering. All right reserved.