Study of the time-varying mesh stiffness of two-stage planetary gear train considering tooth surface wear

Due to the complex structure of the planetary gear train, the influence of early fault on the dynamic characteristics of the planetary gear train is complex and changeable. This paper proposes a time-varying meshing stiffness (TVMS) calculation model of internal meshing considering the coupling effect between teeth; and a multi-tooth coupling stiffness calculation model of the planetary gear train. The Archard equation is used to calculate the wear depth; moreover, the potential energy method calculated The TVMS of the planetary gear train under the wear state. The wear fault will cause the TVMS of the gear to decrease. In the two-stage planetary gear train, the TVMS of the first-stage sun-planet gear decreases more obviously. In addition, there is a specific coupling effect between the sun, ring, and planetary gear. The influence of the wear fault on the two-stage planetary gear train is analyzed by calculating the synthetic stiffness considering the meshing phase difference. The results show that under the same wear fault condition, the more teeth involved in meshing, the more significant the decrease in coupling stiffness.