Abstract
Fatigue failure initiation site in synchronous belts depends on the belt tension and the torque conditions, namely fluctuating torque or constant torque conditions. For example, the tooth root cracking is observed at the tight side under a constant torque, while the tooth root cracking is initiated at the slack side under a fluctuating torque. However, the effects of those mechanical conditions on the failure initiation site have not sufficiently been understood. In this study, the effects of belt tension and tooth load on the failure initiation site were investigated using a FEM analysis. The maximum shearing stress is initiated at the slack side tooth root under low tooth load conditions and at the tight side under high tooth load conditions. It is considered that the former simulates the fluctuating torque conditions and the latter simulates the constant torque conditions.
