Time-varying Mesh Stiffness Calculation And Simulation Analysis Of Gear Transmission System

The gear transmission system is the most widely used power transmission device and is a key mechanical component in the engineering fields of vehicles,machinery,aerospace,metallurgy,electric power,coal and so on.The dynamics simulation of gears is recognized as an effective way to characterize the dynamic characteristics of gear transmission systems.It can describe rather realistically the operation and evolution process of the system,which is helpful to analyze and optimize the parameters of the system to meet the purpose of system design.The gear dynamics model is very complex and has many parameters.The time-varying meshing stiffness is the dominant parameter of the gear transmission system.The possible coupling between the parameters of the model can have a significant influence on the dynamic characteristics of the system.Therefore,it is of great significance to deepen the analysis of the dynamic characteristics of the gear system and study the new calculation method of the meshing stiffness.The main findings of the present work are as follows:(1)Calculation of time-varying meshing stiffness.Combining the potential energy analytical method and the finite element method,the ANSYS-APDL script is programmed to establish an accurate involute gear model,which allows to obtain the strain energy and contact load of meshing gear teeth,a method is proposed,which is based on the elastic deformation theory,for computing the time-varying meshing stiffness.Numerical examples are performed to verify the effectiveness and versatility of the proposed method,and the effects of typical assembly error forms,gear modification and surface modification processes are further studied on gear mesh stiffness.(2)The influences of the manufacturing factors on the gear dynamics.Taking into account different manufacturing processes,the gear dynamics model is established and numerically solved.The dynamic transmission error(DTE)and dynamic meshing force(DMF)curve are then obtained.The results show that the shaft misalignment can increase the oscillation amplitude of DTE and DMF,which reduces the stability of the gear transmission.The gear modification can greatly decrease the amplitude of the response oscillation,reducing the shock vibration during the gear transmission process and improving the gear transmission performance.In addition,the bifurcation and chaos present in gear transmission systems are investigated,which provides theoretical guidance for designing high-performance gear systems.(3)Parameters sensitivity analysis of the gear dynamic model.By employing the global sensitivity analysis method,the parameters affecting the dynamic characteristics of the gear are analyzed.It is shown by the results that the transmission accuracy is mainly determined by the backlash and meshing stiffness,then the meshing stiffness,meshing damping and support damping are mutually coupled,which influences significantly the dynamic meshing force,and finally the stability of gear transmission is very sensitive to the meshing stiffness and support damping.The obtained results in this work is valuable to provide guidelines for the manufacturing process of gearbox.