Dynamic characterization and vibration response optimization of EMT system for tracked vehicles

Electromechanical composite transmission (EMT) is an important transmission form for heavy-duty tracked vehicles, which has higher requirements for the kinematic performance of the whole vehicle under high-speed driving and cross-country high-mobility working conditions. In this paper, for the drive motor-planet mechanism of the tandem EMT system, the electromagnetic torque, unbalanced magnetic tension, and gear nonlinear meshing excitation are calculated, and the influence law of the excitation source on the vibration response at high rotational speed is revealed. Then, the dynamic model of the drive motor-planet mechanism system is established, and the intrinsic vibration characteristics and forced vibration characteristics are analyzed. Secondly, a tooth profile trimming method of the drive motor-planet mechanism based on the minimization of the out-of-line meshing is proposed. The tooth profile trimming amount in each planetary row is obtained, and the mechanism before and after the trimming is analyzed by dynamic simulation. Finally, a vibration test rig is set up to collect the vibration acceleration data before and after gear trimming and verify the validity of the proposed trimming method. The results show that the vibration characteristics of the system are improved by up to 30% after reshaping, which is in good agreement with the simulation results, and the overall deviation is about 15%.