Optimization Design Of Gear System Modification Under Wide Frequency And Wide Range Load

With the development of modern industrial technology,the performance of gear transmission system is also required to be higher and higher.As a special vehicle transmission system,it is not only necessary to operate under high speed and heavy load and other limit conditions,but also to operate smoothly in other speed torque range and complex excitation conditions.Therefore,it is necessary to control the vibration noise of gear transmission system reasonably,and improve the stability and reliability of the system.Gear modification is one of the main ways to improve the transmission performance of gear.Through the modification,the meshing impact of gear can be reduced and the load distribution can be improved,so as to reduce the vibration response of the system.But the same modification parameters have different shape modification effects under different excitation frequency and torque,and even aggravate the vibration response under some conditions.At present,the optimization design of gear modification is mainly aimed at improving the static performance of the system or the dynamic performance under single working conditions,and using Roamx,Kisssoft and other software to optimize the design,while the theoretical research on the optimization design for the dynamic performance under the comprehensive working conditions is less.Therefore,the paper establishes a coupling dynamic model of bending and torsion for gear system excited by wide-frequency and wide-range load.The influence of modification parameters and other system parameters on the inherent,static and dynamic characteristics of the system is analyzed.Finally,the optimization design of the parameters is carried out through multi-objective optimization model,and the purpose of suppressing vibration response is achieved under the comprehensive working conditions.The main contents include:(1)Aiming at the modified gear,the involute tooth profile,root transition curve and modification curve are accurately modeled.Considering the coupling effect of gear modification,tooth profile error,root transition fillet and elastic deformation of gear tooth matrix,the time-varying meshing stiffness model of the improved gear is established based on the elastic potential energy method,and verified by the finite element model.(2)Aiming at the spur gear transmission system,considering the nonlinear factors such as wide frequency and wide range load excitation,manufacturing and installation error excitation,time-varying meshing stiffness excitation and backlash excitation,a bending torsion coupling nonlinear dynamic model of the gear transmission system is established by using the lumped mass method,and system parameters on the natural characteristics are analyzed.(3)According to the static characteristics of the system,the influence of gear manufacturing accuracy and modification parameters on the static transmission error,and the influence of system parameters and modification parameters on the time-varying meshing stiffness are analyzed.According to the dynamic characteristics of the system,the effects of gear manufacturing accuracy,broadband load,backlash and modification parameters on vibration displacement,dynamic transmission error and dynamic meshing force are analyzed,and the dynamic response of modification parameters under multiple steady-state conditions is studied,which provides a theoretical basis for modification optimization.(4)Aiming at the comprehensive working condition of wide frequency and wide range load excitation,the multi-objective optimization model of gear modification is established with the modification parameters as the design variables and the dynamic response parameters as the optimization objectives.The modified genetic algorithm is used to optimize the modification parameters.The results show that the vibration response of the gear system under the comprehensive working condition is significantly reduced after the modification optimization,and the vibration response of each individual working condition is also reduced in varying degrees.