Study On The Dynamic Characteristics Of Planetary Gear System Under The Effects Of Exhausted Oil-dynamic Load-heat

The operation of planetary gears under the conditions of lack of oil-dynamic load-thermal effect will inevitably lead to some more traditional failure forms such as pitting of the sun gear and planetary gear tooth surfaces,tooth surface gluing,etc.These failure modes also cause the transmission efficiency of the transmission system to decrease And the culprit of poor performance.In the research of the thesis,there is less research on the planetary gear under the condition of lack of oil.Therefore,it is essential to study the dynamic characteristics of planetary gears under the effects of exhausted oil-dynamic load-heat.This article will analyze and discuss the dynamic performance changes of the planetary gear system under the conditions of exhausted oil-dynamic load-heat effect.The paper mainly has the following content:(1)Introduce the basic theory of line contact elastohydrodynamic lubrication,derive the finite length line contact theory according to the solution equation given in the numerical calculation method of elastohydrodynamic lubrication,and derive the basic theory suitable for this article.At the same time,the Newton-Raphson iteration method will be introduced,and the established linear contact elastohydrodynamic lubrication theory will be verified.Establish the calculation flow chart of linear contact elastohydrodynamic lubrication,assign values to the variables in the program,and obtain the distribution curve of linear contact elastohydrodynamic lubrication pressure and film thickness and the temperature rise distribution curve of each layer of linear contact elastohydrodynamics and use Newton-Raphson iteration Comparing the pressure distribution of linear contact elastohydrodynamic lubrication obtained by the method with the film thickness shape,it can be seen that the basic theory of finite-length linear contact can be used in the analysis of this article.(2)Establish an isothermal elastohydrodynamic lubrication model of the sun gear and planetary gears in the helical planetary gear under the exhausted condition,derive the lubrication control equation,and perform kinematics analysis on the effective meshing position of the geometric model,according to the given working conditions,Set the numerical solution area to give the flow chart of the isothermal elastohydrodynamic lubrication calculation program,obtain the load curve with time,the pressure distribution curve and the film thickness curve after deformation,and use the aforementioned Newton-Raphson iteration method to consider the rough mesh The surface condition shows the influence of tooth surface roughness on lubrication.(3)Establish the translation-torsion dynamics theoretical model of the planetary gear system.Apply Newton’s second law to derive the dynamic equations of each component in the model,introduce the concept of following coordinate system and use Runge-Kutta numerical method to solve the system equations.Through the analysis of the time-varying meshing stiffness generated when the sun gear meshes with the planetary gears when the planetary gear system is working,the tooth side clearance caused by the meshing phase difference,the meshing error caused by various factors and various excitations,the dynamic load characteristics are obtained.Influence of planetary gear dynamics.(4)This article will use ANSYS to conduct steady-state thermal analysis,thermal stress analysis and thermal modal analysis of the sun gear and planetary gears in the established gear model,and obtain the influence of thermal effects on planetary gear meshing.