System-structure coupling dynamic analysis of planetary gears

This paper presents a novel general system-structure coupling dynamic analysis procedure to comprehensively analyze the dynamic performance of planetary gears. The novel coupling dynamic analysis takes dynamic loads of gears as excitations for structure dynamic analysis. Considering the time-varying mesh stiffness of gears, torsional stiffness of carrier and support stiffness of bearings, the system dynamic model of planetary gears is built by using lumped parameter method. Vibration modes and natural frequencies of planetary gears are investigated through modal analysis. Furthermore, system dynamic response is analyzed under various working conditions. Equations of structure dynamic analysis based on finite element method (FEM) are developed, and their solving method is put forward. Dynamic loads obtained from system dynamic analysis are forced on the ring gear to analyze its structure dynamic response. In every analysis step, if dynamic performance criteria are not satisfied, the planetary gears model should be redesigned according to dynamic analysis results.