Modeling And Vibration Characteristics Analysis Of Parallel Shaft Gear Transmission System Of Emu

With the continuous improvement of EMU running speed,higher requirements are put forward for the stability and safety of the transmission system.In this paper,a EMU transmission system is taken as the main research object,and the EMU transmission system is simplified as a parallel shaft gear transmission system model.The system modeling and vibration characteristics are analyzed by using the finite element theory.The main work and conclusions are as follows:(1)Based on the finite element theory,the axle and traction motor shaft are simplified as multi beam elements,the meshing gear is assumed to be two rigid bodies connected by spring and damper,and the supporting bearing is simplified as a spring damping system.(2)The modal analysis of parallel shaft gear transmission system of EMU is carried out.The natural frequency of the system is calculated,and the difference between the natural frequency of the coupling system and that of the independent system is compared.The Campbell diagram of the system is derived by using the state equation,and the critical speed of the system is calculated.Combined with the modal theory,the difference between the critical speed of the system with and without gyro moment is analyzed.Finally,the effects of gear meshing stiffness and bearing support stiffness on the natural characteristics of the system are analyzed.The results show that the two parameters have effects on the natural frequencies of the system,in which the meshing stiffness has a greater impact on the gear coupling frequency,and the bearing support stiffness has a significant impact on the low order natural frequencies.(3)In view of the low accuracy and divergence of the classical Newmark-β method in solving nonlinear dynamic equations,combined with the advantages of quasi Newton method in solving nonlinear equations without solving the Jacobian matrix of the system,the classical Newmark-β method is improved by using the asymmetric Broyden rank 1 correction.It is proved that the improved Newmark method still has the advantages of high accuracy,good stability and unconditional convergence.(4)The results show that the speed of traction motor has the most obvious influence on the amplitude of the unbalanced vibration response of the system.At the same speed,the amplitude of the system far away from the unbalanced loading position decreases,and the amplitude of the system near the unbalanced loading position increases;When considering the static transmission error of gear meshing,although the system speed does not exceed the critical speed of the system,the resonance phenomenon still occurs,and the frequency corresponding to the peak vibration of the system is the frequency corresponding to the gear coupling vibration mode of the system;The results show that the traction motor will not rub at rated speed,but the speed of traction motor,the gap between rotor and stator,and the change of bearing stiffness will have an impact on the system rub impact response,and the gap between rotor and stator has the most obvious impact on the system rub impact response.