Time-varying mesh stiffness calculation of a planetary gear set with the spalling defect under sliding friction

Time-varying mesh stiffness (TVMS) is an important excitation source of a planetary gear set. Sliding friction and spalling defects have significant effect on the TVMS. Accurate evaluation of the TVMS can help obtain the vibration characteristics and further detect the spalling defects of the planetary gear set. In this paper, an improved analytical model is proposed to calculate the TVMS of the planetary gear set with sliding friction by considering the tooth profile beginning with the root circle. Then the impact of spalling defects on the TVMS is investigated. The results show that the improved analytical model can increase the precision of the TVMS. Besides, the effect of sliding friction and spalling defects on the TVMS is significant. This study offers a basis for dynamic performance analysis of a planetary gear set with spalling defects under sliding friction.