Parametric Instability of Planetary Gear Transmission with Elastic Ring Gear due to Discrete Boundary Strut Parameter Variation

This paper investigates the effects of different boundary strut parameters on parametric instabilities of planetary gear transmission (PGT) driveline system with elastic ring gear over the whole operating speed range. As an example, to demonstrate the PGT system boundary strut design, an optimal design strategy is briefly introduced not only to obtain a light-weight system, but also to satisfy the stress and buckling conditions of the boundary struts. Assumed-modes method is used to discretize the system and Floquet method is applied to the established PGT driveline system with elastic thin ring gear supported by discreate boundary struts to explore the parametric instabilities of the PGT system due to different boundary strut parameter variations. The results show that by properly selecting the boundary strut parameters, the parametric instabilities of the PGT driveline system can be avoided or shifted. Therefore, vibrations of the PGT system introduced by the parametric excitations can be suppressed correspondingly.