An insight into the pass effect of the planet gear from an elastodynamics perspective

Distinguished from parallel-axis gear systems, the revolution of the carrier brings out the pass effect of the planet gear. Compared with the phenomenological descriptions in conventional studies, this paper aims to provide more abundant physical information and the elastodynamics mechanism of the pass effect of the planet gear. To this end, a continuous-discrete model of helical planetary gears is proposed. Considering both the in-plane and out-of-plane vibration, a semi-analytical model is established to simulate the elastic ring gear. The elastic and the lumped parameter submodels are synthesized using the moving elastic coupling boundary. The simulated modal and dynamic characteristics are verified using a planetary gear test rig. Based on the proposed dynamic model, the pass effect of the planet gear, the effects of bolt constraint, and the out-of-plane vibration of helical planetary gears are investigated. It is revealed that the “realistic rotation” strategy adopted in the proposed dynamic model can better reflect the physical essence of the pass effect of the planet gear compared with the “pseudo rotation” strategy utilized in the traditional model.