Nonlinear Dynamics Of Planetary Gear Systems In Oil-Depleted Service Conditions

Planetary gear transmission system is widely used in aviation,automobile and ship because of its high transmission efficiency and small size.The transmission of planetary gears under the condition of spent oil will cause the meshing tooth surface to undergo corrosion,glue and other forms of failure.In the process of transmission,there will be non-linear factors such as combined error and engaging damping.These factors give the planetary gear system a strong nonlinear feature.Therefore,the nonlinear kinetics of planetary gear system is studied in this thesis.It is analyzed and discussed.The thesis has the following contents.(1)In order to study the characteristics of elastofluid lubrication under depleted oil conditions,an isothermal line contact elastofluid lubrication model under depleted oil conditions is established,and the film thickness and pressure distribution of its line contact elastofluid lubrication are obtained through numerical analysis by the multiple mesh method.(2)The external excitation and internal excitation of planetary gear drive system are introduced.The kinetic model of planetary gear transmission system is established by centralized parameter method.By using Newton’s law,the dynamic differential equation of the planetary gearing system is established.Introducing a series of generalized coordinates into the dynamic differential equation,The rigid body shift in the equation is solved by transforming it into a relative displacement.The differential equations of kinetic system are solved by the numerical method of Rungekutta method.(3)Consider the nonlinear dynamics of planetary gear systems in dry friction.Several methods of analyzing nonlinear dynamics of planetary gear system are introduced.The nonlinear characteristics of the planetary gear system are analyzed and verified by bifurcation,phase,Poincaré section,etc.Consider the influence of the planetary gear system on the motion characteristics of the planetary gear system under the excitation factors such as excitation frequency,stiffness amplitude,load and comprehensive error.(4)An isothermal elasticity lubrication model of solar and planetary wheels in beveled-tooth planetary gears in spent oil is established.The basic control equation of elastic flow lubrication is dimensionless,which affects the elastic flow lubrication of planetary gear under different conditions such as lubricating oil viscosity and load.The nonlinear kinetic characteristics of planetary gear system under the condition of spent oil are further discussed.