Tilted flexible suspension of motor and its dynamic effect on high-speed train bogie

In this study, a structure regarding motor flexible suspension on the power bogie is proposed, so as to improve the dynamic performances of the high-speed train. The motor is installed flexibly on the bogie frame with two longitudinal rods and a rubber joint, and this structure is different from the conventional motor flexible suspension on high-speed train bogie. The influence of suspension parameters on the vehicle hunting stability is analyzed by the dynamic simulation using SIMPACK, and the mechanism of improving the dynamic performance is clarified. When the frequency of the motor suspension is close to the bogie hunting frequency, the flexible suspension can reduce the bogie hunting vibration energy, so as to improve vehicle lateral dynamic performances. The mechanism is determined from the dynamic vibration absorber. In this model, the motor flexible suspension significantly improves the nonlinear critical speed of the vehicle and reduces the response of car-body caused by the wheel-rail lateral excitation, especially using the worn tread. The optimal motor suspension frequency is 3~4Hz, and the corresponding nonlinear critical speed is increased by 38% in comparison with the rigid suspension. Furthermore, the robustness of hunting stability to vehicle suspension parameters with this tilted flexible suspension structure is investigated.