Due to the moving loads and complex spatial structure characteristics of helical gears

it is difficult to acquire and diagnose the vibration characteristics of the helical gear with spalling defect. To analyze the failure mechanism caused by tooth surface spalling

by considering the change of contact line length induced by the spalling defect

an analytical model is proposed to calculate the mesh stiffness of helical gear with spalling defect based on the microtomy and the potential energy method. The effects of spalling length and width on the time-varying mesh stiffness are analyzed. At the same time

a six degrees-of-freedom dynamics model of the helical gear is built

the dynamic response with different spalling length and the effects of rotational speed and load on the dynamic characteristics are obtained. The result of study shows that

the proposed new model is able to accurately calculate the mesh stiffness

dynamic response and other characteristics of the helical gears under the influence of spalling defect. The basis for the gear system status detection is provided.