Vibration analysis of a gear-rotor-bearing system with outer-ring spalling and misalignment

Misalignment and spalling of bearing rings are typical errors and faults that significantly influence the vibration characteristics of a gear-rotor-bearing system. In order to investigate the coupling effects of misalignment and spalling, it is necessary to analyze the vibration characteristics of a gear-rotor-bearing system with misalignment and spalling. Firstly, considering the outer ring misalignment and spalling, the 5-DOF nonlinear bearing restoring force is calculated. Then, based on the loaded tooth contact analysis (LTCA) method, the meshing stiffness is calculated, and the dynamic model of the spur gear pair is established. Furthermore, the equivalent stiffness model of the spline is established based on the slicing method. Finally, by coupling the bearing restoring force model, the dynamic model of the spur gear pair, and the equivalent stiffness model of the spline with the finite element (FE) model of the rotor system, a dynamic model of a gear-rotor-bearing system is developed. The analysis shows that the contact force, contact angle, and system vibration are only affected when the spalling is located in load-bearing areas. The misalignment of the outer ring leads to the increase of the load-bearing area range of the bearing and the influence probability of the spalling on the system.