Dynamic analysis of gear system with multiple lubrication states in torque–speed parameter space

The existence of backlash causes de-meshing and reverse impact in the gear system, and the influence of the working lubrication conditions of the gear on the dynamics is ignored. This study focused on the impact of the coupling characteristics of gear system based on the multi-meshing state model and the gear lubrication model on the evolution of nonlinear dynamic behavior. Firstly, the transition of the meshing state was considered, and the time-varying parameters such as contact radius, load distribution ratio, meshing stiffness, entrainment speed, and slip-to-roll ratio were analyzed under meshing and reverse impact conditions. Then, the elastohydrodynamic lubrication model of the gear was analyzed, the coupling effect between the lubrication model and the gear system was reflected by two factors. One was the comprehensive meshing stiffness obtained by coupling the gear meshing stiffness and the lubricating oil film stiffness, and the other was the lubrication state transition of the system determined by the oil film thickness. Further, the gear dynamics model considering the above factors was established, and the influence of the coupling characteristics of lubrication and gear systems on the dynamic behavior was analyzed on the torque–speed parameter plane. The research results have theoretical guiding significance for the parameter selection, optimization design of gear system and the optimization of meshing characteristics.