Five-state engaging model and dynamics of gear-rotor-bearing system based on time-varying contact analysis considering gear temperature and lubrication

Abstract

Contact behavior of gear teeth plays a key role in modeling and analysis of geared systems. To reasonably evaluate the time-varying contact characteristics of spur gear systems, a new load-dependent time-varying meshing stiffness model incorporating elastic contact stiffness, temperature stiffness and oil film stiffness is developed. Asperity pressure and lubricant pressure are considered for the oil film stiffness. The engagement of the gear pair is decomposed and classified based on the time-varying contact analysis and then five meshing states are obtained. A novel nonlinear dynamic model of the gear-rotor-bearing system with 5-state mesh including time-varying backlash and time-varying meshing stiffness is established by introducing multiple state sub-functions. The effects of gear temperature and load on the meshing stiffness are analyzed. 5-state meshing behavior is identified and characterized by constructing 5 Poincaré maps. The bifurcation and evolution of 5-state meshing behavior are investigated by changing parameters. Distribution of multi-state meshing behavior in two-parameter planes is analyzed to obtain the correlation between multi-parameter and multi-state behavior. The results demonstrate that temperature and load greatly affect the time-varying meshing stiffness, of which the temperature stiffness contributes the most and the oil film stiffness contributes less. The parameters change the system dynamics by affecting the multi-state meshing behavior. The dynamic behavior is highly dependent on the matching and combination of multiple parameters. Diversity of multi-state meshing behavior is clearly revealed. The presented results provide an understanding of the time-varying engaging characteristics and therefore serve as a useful source of reference for engineering in designing and controlling such gear systems.