Study On Dynamic Characteristics Of Compound Planetary Gear And Wear Mechanism Of Its Thrust Washer

Compound planetary gear set (CPGS) is widely applied in the mechanicaltransmission systems,especially in automatic transmission system.The performanceof CPGS has an important influence on the automatic transmission system.How toreduce noise and vibration and how to improve the effectiveness of load sharing aremain research contents of the dynamic characteristics of CPGS.In the application ofthe spur CPGS,the washer between planetary gear and the frame was distressedheavily and the reason is unknown.Therefore,it's the important subject for theimprovement of the automatic transmission system to research the dynamiccharacteristics,load sharing and the reason of washer distress.Chapterâ… ,the application of CPGS was introduced and the background andresearch significance were discussed.Then the work of previous studies weresummarized,focusing on an overview of planetary gear free vibration characteristics,load sharing,axial force and distress of the washer.Finally,research idea and themain study of this paper were introduced.Chapterâ…¡,the dynamic model of CPGS was established.Firstly,the movingcoordinate system of CPGS were established;then considering time-varying meshingpair mesh stiffness,tooth profile error,the planetary gear meshing phase and otherfactors the vibration differential equations of each CPGS component were establish;Finally,the equations of each component were integrated to obtain the systemdynamic model for the future research.Chapterâ…¢,system model of chapter II was simplified as the free vibrationmodel of the system to solve the inherent vibration frequency and vibration mode.The inherent vibration modes are divided into three categories:torsional vibrationmode of central component,translational and torsion pendulum vibration mode of thecenter component and (double) planetary gear vibration mode.Then the sensitivity ofnatural frequencies to the main parameters was studied and the phenomenon of modal transition was investigated.Finally,the influence of time-varying mesh stiffness andgyroscopic effect on the natural frequencies was studied.Chapterâ…£,both time-varying and time-invariant errors which influence the loadsharing of CPGS was analyzed.The dynamic equations of Chapter II were modifiedand the coefficient of load sharing was defined.Then the influence of main errors,operating conditions,support stiffness,time-varying mesh stiffness and the number ofplanetary gear on load sharing of CPGS was studied.Finally,tests were carried out.Chapterâ…¤,experiment was done to research the axial force between planetarygear and frame and the relation between axial force and radian force was obtained.The theoretical analysis of generation mechanism of axiai force was discussed.Chapterâ…¥,the operating status and the environment of the washer weredescribed and then the thermal model of the washer was set up.The washer'stemperature field was solved by finite element method and its influencing factorswere also studied.Finally,the thermal-structure coupling characteristics of the washerwere investigated.Chapterâ…¦,the main results and conclusions of the dissertation weresystematically summarized;the prospects and study emphases of the further researchwork were discussed and forecast.