Nonlinear Dynamics And Fault Analysis Of Rail Transit Gearbox Transmission System

With the acceleration of the pace of life,the rail transit vehicles dominated by high-speed rail,motor trains and subways have become the trend of modern traffic development,and the resulting safety issues have become more and more concerned.The problems that cause rail transit faults are various,but the fault of the transmission system has always been an important problem that cannot be avoided.The gearbox is one of the most widely used transmission components in rail transit vehicles.There are two types of applications in the reduction gearbox.One is the two-stage spur gear transmission gearbox,the other is the one-stage helical gear transmission gearbox.In this paper,the models of these two gearboxes are studied respectively.The 9-DOF system model of the two-stage spur gear transmission gearbox and the 6-DOF system model of the first-stage helical gear transmission gearbox are respectively established and established in the model.The situation of stiffness and wear failure of these two gearboxes is analyzed separately.The variable-step Runge-Kutta numerical integration method is used to solve the two gearbox transmission models with faults,and the dynamics of the system vibration are obtained respectively.Response process.In the analysis of the obtained results,the system state evaluation criteria such as phase plan,Poincaré section,bifurcation diagram and spectrogram are used to qualitatively analyze the periodic motion of the system when the excitation frequency and fault parameters change.The evolution of motion and chaotic motion,and quantitative analysis using RMS,kurtosis values,peak-to-peak and other statistical indicators in appropriate places,the results show:1?For the two-stage spur gear transmission system,when the gear is in normal operation,the vibration of the output shaft gear undergoes the process of single-cycle motion chaotic motion double-cycle motion as the shaft frequency increases.When the gear stiffness fault occurs,the high frequency It will reduce the critical axis frequency of chaotic motion to double-cycle motion,and will cause the RMS,kurtosis value and peak-to-peak value to decrease linearly at the corresponding frequency;while the uniform wear fault will change the period motion at high frequency.For chaotic motion,the RMS value and the peak-to-peak value are both declining,so that the kurtosis value increases first and then decreases,and reaches the highest point when the wear amount is reached.2?For the first-stage helical gear transmission system,when the gear is in normal operation,the output shaft gear undergoes a five-stage change process of single-cycle motiond ouble-cycle motion single-cycle motion double-cycle motion chaotic motion,and the single-tooth stiffness fault causes the gear at low frequency.The system gradually evolves from single-cycle motion to double-cycle motion.At high frequencies,the gear system gradually evolves from double-cycle motion to chaotic motion,which increases the sideband of the fundamental frequency and frequency multiplication.The full-tooth wear fault also occurs at low frequencies.The gear system gradually evolves from single-cycle motion to double-cycle motion.At high frequencies,the gear system gradually evolves from chaotic motion to double-cycle motion,and the sidebands of the fundamental frequency and frequency multiplication are reduced.In the later stage,the RMS value,kurtosis and peak-to-peak value are greatly affected.The full-tooth wear fault has a great influence on the RMS value,kurtosis value and peak-to-peak value at the initial stage of the fault.The motion state of the two-stage spur gear transmission system and the first-stage helical gear transmission system vary with the axle frequency,and the response of each system to the stiffness failure and wear failure changes are also different.Finally,the correctness of some conclusions is verified by experiments,and the role of the results in practical application is analyzed.