Vibration signal modeling of planetary gearbox based on dynamics and finite element method for tooth crack diagnosis

Abstract

Planetary gear set contains many kinds of nonlinear factors, such as time-varying meshing stiffness, bearing support, backlash, and comprehensive transmission error, which will deeply affect the gearbox response behaviors and vibration characteristics. During the operation of planetary gear set, there are several gear pairs meshing simultaneously, which will lead to multiple vibration sources and complicate vibration transmission. The revolution of the planet gears makes the meshing force of the gear pairs vary periodically, and the continuous motion of the meshing point also changes the length of vibration transmission path. This study aims to establish a hybrid model that can simulate the vibration signals of gearbox measuring points through fusing the dynamic model of planetary gear set and the transmission path model. Through the simulation analysis, the vibration characteristics of the measuring point signal of the planetary gearbox are revealed, and the crack fault of the planet gear tooth is effectively isolated. Finally, the availability and validity of the presented model are experimentally verified, and the magnitude match is up to 78%. The model can not only provide a theoretical basis for data-driven fault diagnosis methods, but also solve the pain point of diagnostic samples scale and balance by simulation means.