Research on the Influence of Mesh Stiffness of Fixed Gearbox with Chipping Fault

Gearbox is a key component in rotating machinery and prone to chipping fault due to poor working environment. Hence, it is necessary to carry out research on chipping fault. Time-varying mesh stiffness is a periodic function caused by the change in the number of contact tooth pairs and the contact positions of the gear teeth. Time-varying mesh stiffness of is one of the main sources of vibration of a gear transmission system. Time-varying meshing stiffness provides the important information about the health status of the gear system. When a chip happens in one gear, mesh stiffness will decrease and consequently the vibration properties of the gear system will change. The vibration change can be characterized through gearbox dynamic modelling approach. In order to comprehensively understand the vibration properties of a gear set, it is essential to evaluate the time-varying mesh stiffness effectively. In this paper, the potential energy method is applied to analytically evaluate the time-varying mesh stiffness of a gear set. A modified cantilever beam model is used to represent the external gear tooth and analytical equations are derived without any modification of the gear tooth involute curve. A chip model is developed and the mesh stiffness reduction is quantified when chipping fault occurs in the pinion or the gear.