Time-varying stiffness model and dynamic response characteristics of gears with tooth surface spalling and edge contact

Dynamic response characteristic of gears with tooth surface spalling is an important message to their fault diagnosis. However, the complexity of mesh deformation in tooth surface spalling area and its strong coupling with response signals result in a difficulty to diagnose gear early faults. Here, a dynamic model of gears with tooth surface spalling based on a time-varying stiffness for edge contact was built to explore the response characteristic mechanism in tooth spalling area and the new time-varying meshing stiffness algorithm was also established. The time-varying stiffness excitation and the gear system dynamic response with edge contact were analyzed. The study on the mutation characteristic of edge contact force at tooth surface spalling boundary and the dynamic response characteristic of the gear system was performed with time domain and frequency domain methods. In addition, the experimental investigation on the dynamic response features of the gear system with tooth surface spalling fault was performed to validate the proposed theoretical method. The simulation and experimental results showed that the new model can be used to correctly calculate the effect of tooth surface spalling on the mesh stiffness and the dynamic response features of gear systems, it provides an important reference for condition monitoring of gear systems.