Dynamic modeling of planetary gear set with tooth surface wear

Wear commonly occurs in planetary gear transmission systems. Fundamentally, the tooth wear could cause tooth profile deviation, which would increase the vibration and noise of gearbox. In order to monitor and forecast the wear condition of gears via vibration-based methods, it is necessary to establish the dynamics model of a planetary gear set with tooth surface wear, which can provide a prior about the vibration characteristics of gear wear. In this study, a purely torsional dynamics model of a planetary gear set with tooth surface wear is proposed to analyze the fault mechanism of tooth surface wear. The tooth surface wear is incorporated into the dynamics model through unloaded static transmission error (USTE) and time-varying mesh stiffness (TVMS), which are evaluated by Archard's wear equation. Subsequently, the vibration responses of the planetary gear set with tooth surface wear are analyzed. It is revealed that tooth wear would change the vibration responses in both time- and frequency-domain and the condition indicators present different trends. 2019 The Authors.