Research on Load Sharing Characteristics of Face Gear–Planet Gear Composite Transmission System

This study investigates the load-sharing characteristics of a face gear–planet gear composite transmission system. A translational–torsional coupled dynamic model incorporating gear eccentricity errors is developed, with the system featuring 6N+17 degrees of freedom. The model integrates multi-dimensional parameters such as eccentricity errors, support stiffness and input power to analyze the dynamic responses of meshing forces (MFs) and load sharing coefficients (LSCs). The fourth-order Runge–Kutta method is employed to solve the dynamic equations, while the time-varying meshing stiffness of face gears is calculated via finite element analysis and expanded as a Fourier series to address periodic excitations. The results show that the MFs range from 1.3 × 10⁴ N to 1.75 × 10⁴ N for the face gear system and from 1.5 × 10⁴ N to 3.5 × 10⁴ N for the planetary gear system. The LSCs vary between 0.92–1.08 and 0.7–1.3 for the respective systems. Parametric studies reveal that reducing eccentricity errors, increasing support stiffness, or elevating input power significantly improve load distribution uniformity. This research provides a theoretical foundation for the dynamic design and error control of composite transmission systems.