Coupled vibration characteristics of hybrid gear transmission systems

To explore the coupled dynamic characteristics of the gear transmission mechanism in hybrid vehicle drivetrains, this research incorporates critical factors including time-varying mesh stiffness, dynamic transmission errors, backlash-induced discontinuities, and nonlinear bearing forces. Based on these parameters, a nonlinear dynamic model of a gear-rotor-bearing coupling system incorporating multi-stage gear pairs and rolling bearings was established, and the nonlinear dynamic vibration differential equations for the gear pairs were derived. The Runge-Kutta method was employed to determine the dynamic responses of the system under a wide range of operating conditions. Through bifurcation analysis, time-domain response curves, phase portraits, FFT spectra, and Poincaré sections were generated to reveal the comprehensive characterization of the nonlinear dynamic behavior of the system. Finally, the multi-scale method was applied to investigate the relationships between vibration responses and meshing stiffness, load fluctuations and meshing damping. The results demonstrate that excitation frequency significantly affects vibration characteristics, and selecting optimal excitation frequencies can effectively reduce vibrations.