Research On Nonlinear Dynamic Characteristics Of Gear-Rotor System

The gear transmission,as one of the most widely used power and motion transmission devices,has many obvious advantages such as accurate and reliable motion,long life and high transmission efficiency.It is commonly used in energy,transportation,aerospace and other industries.At present,all kinds of mechanical equipment are developing in the direction of high stability and high quietness.As a strong nonlinear system,the nonlinear vibration analysis of gear system has become a hot topic in the mechanical industry.Therefore,it has great scientific and technological value to study the modeling method and vibration characteristics,which lays the foundation for the future theoretical research on gear system.This paper takes the single-stage gear system as the research object,and focuses on two aspects of theory and experiment.Firstly,the vibration characteristics of the gear system under various nonlinear factors are studied by using the MATLAB numerical simulation software.Finally,the theoretical research is verified through the gear experimental platform.The main contents of this paper are as follows:(1)The internal force equations about strong non-linear factors,such as time-varying backlash and tooth surface friction,are established by using gear system dynamics.A simple numerical calculation is carried out according to the relevant parameters in the model.The gear-bearing system model with 6-DOF under dynamic excitations are established by Lagrange equation.The dynamic differential equations are solved by Newmark-β,and the dynamic characteristics of the system are analyzed by system parameters(eccentricity,error amplitude,support stiffness).(2)Based on the rotor dynamics and gear dynamics,a coupled lateral-torsional nonlinear dynamic model with 16-DOF of gear-bearing-rotor system is established,which takes the effect of bending-torsion coupling between transmission shaft and bearing into account.The influences of tooth surface friction coefficient,meshing stiffness and transmission error on the vibration characteristics of the gear system are studied through the obtained response curve.The results show that the motion state of the system tends to be more complex with the increase of friction and stiffness,and the amplitude also increases significantly.(3)After establishing the experimental platform of gear-rotor system,the vibration signals of gears at different rotational speeds are extracted by Labview software and NI acquisition equipment.The mean square value curve of the simulation data and experimental data at different speeds can be obtained.The spectrum response of the system is obtained by Fourier transform of the experimental signal,and the frequency domain characteristics about the simulation and experiment are analyzed.The validity of the simulation results can be verified by the above analysis and comparison.