Nonlinear dynamic analysis of an external gear system with meshing beyond pitch point

A two-dimensional non-linear dynamics model of a gear with meshing beyond pitch point with six degrees has been established, considering time-varying meshing stiffness, time-varying bearing stiffness, time-varying friction, backlash and bearing clearance. Time-varying meshing stiffness is computed by using material mechanics method. The friction coefficient of Coulomb model and the friction coefficient of EHL theory are analyzed and compared in dynamic response. The global bifurcation characteristics caused by input speed, backlash, bearing clearance and damping are investigated. The maximum Lyapunov exponent which leads to chaos characters effect of changing parameters is analyzed. The verification experiment is carried out on the CL-100 test rig. Meshing frequency has main impact on vibration acceleration of ordinary spur gear and double meshing frequency has main impact on vibration acceleration of gear with meshing beyond pitch point. The results show that the gear with meshing beyond is better than ordinary spur gear whether in bifurcation characteristics or in vibration acceleration response.