Dynamic Modeling of Planetary Gear Reducer in High-Torque Hub Drive System

The hub drive system has emerged as a promising development orientation for future vehicles, with the planetary gear reducer serving as its key power transmission component. Considering the complexity of the reducer’s dynamic characteristics under high-torque conditions, this study establishes a lumped parameter translational–torsional coupling dynamic model for the two-stage planetary gear reducer based on Lagrange’s dynamic equations, incorporating critical nonlinear factors such as time-varying meshing stiffness and tooth clearance. No-load vibration tests were conducted to collect vibration acceleration of the secondary planet carrier and the primary ring gear under the operating condition of the primary sun gear rotating at 606 r/min. Experimental verification indicates that the errors between the simulation results and experimental acceleration amplitudes are 9.09% and 14.63%, respectively, confirming the validity and reliability of the theory model. This translational–torsional coupling dynamic model provides significant theoretical support for the dynamic optimization design, vibration control, and performance improvement of reducers in high-torque hub drive systems.