Research On Nonlinear Characteristics And The Coupled Bending-Torsional Vibration Of Gear-Rotor-Bearing System

Gear-rotor-bearing system is the key system of the transmission device,and is widely used in aviation,automobile,shipbuilding and other industrial fields.When the system is running at high speed,the bending vibration and torsional vibration of the system will interact with each other,and show complicated nonlinear vibration characteristics so that the safety and stability of the operating equipment will be endanger.Therefore,it is of great theoretical and engineering significance to study the dynamic nonlinear vibration characteristics of the gear rotor bearing system to analyze the influence mechanism of the bending and torsion coupling vibration,to optimize the design of the parameters of the transmission system and to avoid the severe vibration caused by the resonance phenomenon.This paper takes the gear rotor bearing system of a front steering mechanism of a complex transmission system as the research object.In view of the problems of bending and torsion coupling and multi factors mutual excitation,the study of the inherent characteristics and the unbalance response of the system and the influence of the system parameters on the nonlinear vibration characteristics of the system are carried out.The main work of this paper is as follows:(1)A dynamic model of the gear rotor bearing system is established and the integral transfer matrix method is used to solve the critical speed and steady state unbalance response of the gear rotor bearing system.The influence of the system parameters,such as the integrated mesh stiffness,the support stiffness and the eccentricity,on the critical speed and the steady-state unbalance response of the system is studied;(2)In view of the characteristics of the gear rotor bearing system,there exist both the gear pair meshing and the spline coupling.Considering the nonlinear factors such as the time-varying meshing stiffness,the tooth side gap,the comprehensive transmission error of the gear and the misalignment of the spline coupling,nonlinear dynamic model of the bending and torsion coupling vibration of the engaging force and the meshing force of the middle spline is established;(3)Combining the phase diagram,the bifurcation diagram,the FFT spectrum diagram,the Poincare section map and other nonlinear analysis methods,the influences of the parameters of the meshing frequency,the tooth side gap,the static transmission error of gear and the static misalignment of the spline on the characteristic of the bending and twisting vibration of the typical position of the system are analyzed;(4)Taking into account the meshing force of the gear and the meshing force of the intermediate spline,the nonlinear Hertz force model of rolling bearings,which takes into account the factors of the raceway waviness,the number of roller and the radial clearance of the bearing,is introduced.Using the numerical simulation method,the influence of raceway waviness,roller number and radial clearance on the nonlinear bifurcation characteristics and stability of the system is analyzed by the phase diagram,the Poincare section and the bifurcation diagram.