Analysis of influence of thermal tooth backlash on nonlinear dynamic characteristics of planetary gear system.

A thermal tooth backlash model of a planetary gear system, which includes the effects of thermal deformation and thermal elastohydrodynamic lubrication film, was established. The variation laws of tooth backlash under variable speed, variable torque, and constant power conditions, as well as the nonlinear dynamic characteristics of the system were analyzed. The results showed that the change in tooth backlash is greatly influenced by thermal deformation numerically, while the thermal elastohydrodynamic lubrication film affects the trend of tooth backlash along the meshing line direction. Combining bifurcation diagrams, Largest Lyapunov exponent plots, poincaré sections, phase portraits, and frequency spectra analysis reveals that under variable speed and constant power conditions, the presence of thermal tooth backlash reduces the chaotic range of the system and transforms some unstable motion states into more stable ones. However, for variable torque conditions, the influence of thermal tooth backlash on the system is more complex with both stable and unstable situations coexisting. This study provides a theoretical basis for selecting backlash parameters in planetary gear system design and avoiding chaotic responses. [ABSTRACT FROM AUTHOR]