Dynamics modeling and vibration simulation of planetary gearbox with bearing faults

Abstract

Planetary gearbox is a complex power transmission system which contains a large number of nonlinear contact interfaces and coupled vibration transfer paths. The vibration mechanism of planetary gearbox is very complicated and it's difficult to accurately describe its running state by vibration signals. In this paper, a nonlinear multibody dynamic model of planetary gearbox is proposed. Based on the bearing's parameters, the simulated response signal of Inner ring fault is calculated and transformed into fault excitation force. Based on SIMPACK software, the vibration responses of the gearbox model with bearing fault excitation force are obtained. To verify the simulation results, vibration signals at 4 different monitoring points of an actual planetary gearbox with bearing inner ring fault are analysed. The bearing fault characteristic frequency on medium-speed shaft is detected. Finally, the vibration responses of the actual planetary gearbox and the multibody dynamic model are compared. It shows that the main frequency components of the simulated vibration response agree well with the experimental results. The dynamic model of gearbox in this paper can provide guideline for the fault diagnose of planetary gearbox.