The time-varying mesh stiffness modeling of gear system with spalling defects in different positions

Gear as a critical component of transportation, its operating status has a direct impact on traffic safety. Under the high speed and heavy load, the spalling is one of the main failure mechanisms of the gear teeth. This study focuses on the effect of spalling defects in different positions on the time-varying mesh stiffness (TVMS). By studying the distribution of meshing force in meshing process, a torque was found when the teeth mesh in the spalling region. Thus, a torsional stiffness is introduced to indicate the effect of different spalling positions. And a time-varying meshing stiffness model considering torsional stiffness is established. The result shows that the TVMS decreases when the teeth are engaged in the spalling region with the spalling width increasing. The increase of spalling offset distance also results in a reduction of TVMS. This is due to the fact that both the spalling width and the spalling offset distance cause the change of torque. Moreover, the spalling length affects the range of meshing stiffness and the teeth meshing area. Based on the above model, quantitative results are obtained for the spalling defects in different positions.