Multi-state Meshing Dynamics Modeling And Dynamic Characteristics Research Of Bevel Gear Transmission Syste

Bevel gear transmission system is an important part of vehicle transmission device,its working performance directly affects the comfort,stability and safety of vehicle driving.With the popularization of family cars,higher requirements are put forward for bevel gear transmission accuracy,vibration and noise.The study of vibration mechanism and the influence law of bevel gear transmission system not only provides theoretical basis for system parameters design and dynamic characteristics control,but also provides data support for vibration and noise reduction in engineering.It has certain theoretical research value and practical engineering significance.The research object of this paper is the straight bevel gear transmission system in car differential.Considering the dynamic meshing factors such as time-varying mesh stiffness,load distribution rate,backlash,meshing damping and comprehensive transfer error,a torsional-bending-axial nonlinear dynamics model of straight bevel gear transmission system with multi-state engagement is established,and its multi-state engagement characteristics and nonlinear vibration characteristics are studied.The main contents are shown as follows:1.Based on the potential energy method,infinitesimal method and theory of gearing,the calculation models of the time-varying load distribution ratio and meshing stiffness of straight bevel gear transmission system are established,and its evolution along the line of action is analyzed.Provide the foundation for precise modeling of system dynamics.2.The coupling relationship between backlash and contact ratio is considered comprehensively,it is judged that the straight bevel gear transmission system has five motion states,such as single/double drive-side teeth engaging,teeth disengagement,single/double back-side teeth engaging,a torsional-bending-axial nonlinear dynamics model of straight bevel gear transmission system with multi-state engagement is established.The interaction of several dynamic meshing factors such as time-varying mesh stiffness,load distribution ratio,backlash,meshing damping,comprehensive transmission error and bearing support are considered in the model.It provides a theoretical basis for studying multi-state engagement characteristics and nonlinear vibration characteristics of the system.3.According to the multi-state engagement characteristics of the system,the nonlinear dynamics equation of the system is solved numerically by variable step Runge-Kutta method.Phase diagram,Poincaré map,positive pressure and load distribution ratio along the line of action are used.The mechanism of multi-state engagement in straight bevel gear transmission system is studied.4.Three kinds of Poincaré sections are defined.through the time history diagram of positive pressure,phase diagram,Poincaré map,bifurcation diagram and corresponding Top Lyapunov exponential diagram(TLE).The influence of external excitation(meshing frequency,load coefficient and bearing stiffness,etc.)and internal excitation(backlash,mesh damping and comprehensive transfer error,etc.)on the nonlinear dynamic characteristics of the system is studied.