Abstract: A torsional and translational vibrory model excited by time-varying mesh stiffness and composite gear errors is established to predict the dynamic characteristics of encased differential gear train. The run-out errors are also included in the analysis. A numerical method is applied to solve the large parametrically excited differential system. From the numerical results, it is concluded that the load equalization on each power branch can be not achieved with floating the center-gears in the high speed region. The locus of the center-gears appears that the predominant mode of vibration of center-gears transit from translational mode to rotational mode of vibration. At the time of the occurrence of the resonance in the system work-speed range, the dynamic load of the planetary gear train is much more largely influenced than that of the star gear train.

Key words: Encased differential gear train, Gear dynamics, Vibration