The tooth tip chipping refers to a piece of material breaking away from the tooth tip, which is a common local defect in planetary gear transmissions due to the repeated meshing impact and harsh working environment. It deteriorates the transmission performance and fatigue life, and even results in safety accidents. Thus, it is imperative to investigate the failure mechanisms by developing reliable dynamic models. This study conducted a comprehensive analysis of a planetary gear transmission with tooth tip chipping from the viewpoints of dynamic modeling and fault detection. Firstly, an improved time-varying mesh stiffness (TVMS) model for tooth tip chipping is proposed, in which a new term called torsional stiffness is introduced to reflect the asymmetric load due to the chipping defect. The effects of chipping defects on the TVMS are analyzed by evaluating the TVMS under different chipping size parameters. Then, a dynamic model of a planetary gear transmission is developed. On this basis, the influences of chipping defects on the vibration responses are revealed in time domain and frequency domain.

Tooth tip chipping,improved TVMS model,planetary gear transmission,vibration analysis