Dynamic characteristics of spur gear pair considering meshing impact and multi-state meshing

Meshing impact is caused by boundary impact, mesh-in impact, mesh-out impact and switching impact of meshing teeth pair for gear pair. To study the characteristics of these impacts and their influence on the system dynamic performance, meshing impact is classified according to multi-state meshing. Calculation models of switching impact including impact force and impact time are established based on Hertz contact theory. Calculation model of boundary impact including drive-side boundary impact and back-side boundary impact is constructed on the principle of conservation of energy. An improved nonlinear dynamics model of spur gear pair considering meshing impact is established as multi-state meshing and time-varying parameters are included. It is solved in C program language by Runge-Kutta method numerically. Five representative typical cases are selected to discuss the characteristics and possible motion patterns of the system after considering the meshing impact. The influences of meshing frequency and load coefficient on the system dynamic characteristics and nonlinear dynamics are investigated according to bifurcation diagrams with and without considering the meshing impact and other well-known crucial tools in nonlinear dynamics analysis. Motion transition mechanism of the system considering meshing impact is discussed. The relationship between input and output torque is attempted to deduce according to dimensionless parameters and the engineering significance of the influence for dimensionless load coefficient on the system dynamic characteristics is discussed. It provides a theoretical basis for revealing meshing impact mechanism of the system and further reducing the impact.