Dynamic Analysis And Vibration Reduction Method Of Gear Transmission System

As an important rotating mechanical device,gear transmission system is widely used in aerospace,high-speed locomotive,petrochemical industry,power generation and other fields.The gear transmission system has bad working environment,complicated dynamic excitation,large vibration noise,and is vulnerable to a certain degree of damage.Nowadays,the reliability of gear transmission system is more and more demanding,so it is necessary to further understand the nonlinear phenomena involved in gear transmission system and the vibration reduction method.Therefore,the dynamic characteristics of gear transmission system are studied by establishing the dynamic model of gear transmission system which contains various practical factors,and the vibration reduction method of gear transmission system is explored to ensure the safe and stable operation of the rotating equipment.Based on the above problems,this thesis carries out the numerical simulation research on the dynamic characteristics and vibration reduction methods of gear transmission system by taking the involute cylindrical spur gear transmission system as the research object and using the theoretical calculation model of system,.The main work is as follows:(1)A nonlinear dynamic model of 6-DOF gear transmission system is established by considering the internal and external dynamic excitation factors of gear.Based on nonlinear vibration theory,the bifurcation diagram of system under different excitation frequencies is drawn with support stiffness,support damping and external load as the control parameters,and the dynamic orbit of system is observed.At the same time,the dynamic characteristics of gear transmission system are determined from the phase plane diagram,Poincare diagram and time domain response diagram and amplitude-frequency spectrums of system.The results show that the effect of the support stiffness on the dynamic characteristics of system is complex and related to the value of excitation frequency;the support damping and external load have certain influence on the system,and the stability of system will be improved when the damping and external load are more larger.(2)During the meshing process of gears,there will be friction heat and change in working environment,resulting the temperature changes of gears and boxes,thus causing thermal deformation and affecting the transmission characteristics.Therefore,according to the relevant knowledge of mechanical thermal deformation,the influence of temperature in the meshing process of gears is analyzed.A 6-DOF dynamic model considering the temperature effect is established to study the influence of temperature and excitation frequency on the dynamic characteristics of the system.It is found that the temperature will affect the dynamic characteristics of system.With the variation of excitation frequency,the motion state of the system presents a variety of response forms such as single-period,multi-period,bifurcation and chaos.(3)In order to study the effect of SFD on the vibration characteristics of gear transmission system,a 10-DOF dynamic model of gear-shaft-SFD system is established.The dynamic responses of system with damper and without damper are compared,it is found that the vibration response of system within a certain speed range can be effectively suppressed after the damper is installed.At the same time,the effects of parameters of SFD on its vibration reduction performance is studied,which provides a reference for matching reasonable design parameters of SFD.