Nonlinear response analysis of gear-shaft-bearing system considering tooth contact temperature and random excitations

Abstract

• A coupled nonlinear dynamic model of gear-shaft-bearing transmission system is established. • The time-varying stiffness caused by the contact temperature of tooth surfaces is deduced. • The contact temperature of tooth surfaces can obviously change the periodic motion of the system. • The fractal backlash can reflect the dynamic characteristics of the system more accurately. • The random load can change the form of the system leading to chaos. A coupled nonlinear dynamic model with 10-degree-of-freedom (10-DOF) of gear-shaft-bearing transmission system is established after comprehensively considering the nonlinear features associated with time-varying meshing stiffness (the stiffness caused by temperature and shock), static transmission error, time-varying fractal backlash, friction, load fluctuation, gear eccentricity, gravity, and nonlinear oil film force. The time-varying meshing stiffness caused by the contact temperature of tooth surfaces is deduced, and the effects of the friction coefficient and the normal load on flash temperature are analyzed. Based on the nonlinear differential equations, the coupled multi-body dynamic responses of the gear transmission system are demonstrated using the Runge–Kutta numerical method, and the effects of contact temperature, fractal backlash, and random load on the dynamic characteristics are investigated. The numerical simulation results show that the contact temperature of tooth surfaces can obviously change the periodic motion of the system; the fractal backlash can reflect the dynamic characteristics of the system more accurately; the random load can change the form of the system leading to chaos. The influence of the contact temperature of tooth surfaces and the random excitations should be considered in the dynamic modeling of systems. The study can provide a basis for the fault diagnosis of the gear transmission system.