Abstract: A new type of electric ARFF vehicle developed in China is taken as the research object. The dynamic response of the power coupling transmission device under heavy load and high speed condition is analyzed by dynamic simulation. The dynamic model is established by considering the nonlinear characteristics of the gear transmission in detail, such as time-varying stiffness and backlash. The gear shaft is considered as a flexible shaft based on Timoshenko beam theory. The bearing force is calculated by Lamina model according to the geometric characteristics of the bearing type. The results show that the 44th order caused by gear meshing contributes most to the overall level vibration of the power coupling device, and there is an obvious resonance peak near 2 568 r/min in reverse condition. Through the analysis of operational deflection shape, it can be seen that the resonance is related to the flexible vibration mode of the output shaft. Increasing the section size of the output shaft can effectively improve its bending stiffness and change the vibration frequency, so as to avoid possible resonance in the range of working speed and improve the linearity of the system order.

Key words: electric ARFF vehicle, drive system, power coupling, gear