Torsional Vibration Modelling of a Two-Stage Closed Differential Planetary Gear Train

In this paper, a torsional dynamic model of a two-stage double-helical planetary gear train is developed, and the vibration characteristics and coupling relationship are studied. Firstly, a purely torsional model was established based on structure diagram and different mesh phasing. Then, the runout error is taken into account. Finally, according to frequency spectrum analysis, the coupling relationship of two stages is studied. It is shown that the runout error of the planet in different stages has a different impact on the torsional vibration of transmission error. It also shows that the coupling relationship exists and affects each other between two stages, and the excitation frequency for the output element of two stages can be composed of a series of the mesh frequencies of each stage, the meshing frequency of high stage (1st stage) is dominated in two stages.