| The planetary gear transmission system has the characteristics of single-stage multiple planetary gears to distribute the load,which is smaller and lighter than the general gear transmission.The closed differential planetary gear transmission has a power split between the closed and differential stages.It is smaller and lighter than the ordinary planetary transmission,so it is widely used in aerospace,automobile,wind power and other fields.However,due to the limitations of processing equipment,precision and other conditions,the planetary transmission system inevitably has manufacturing and installation errors of various components,coupled with the deformation of various components of the system,and the load distribution between the planetary gears of the planetary transmission is often uneven,resulting in Dynamic load,vibration,noise and stress fluctuations in the system seriously affect the stability and reliability of the transmission system.Therefore,more and more attention has been paid to the load sharing problem of the closed differential planetary transmission system.This thesis takes the closed differential planetary gear train of a certain type of aeroengine as the research object.Based on the finite element theory and concentrated mass method,the two-node 12-degree-of-freedom spatial beam element is used to establish the time-varying meshing stiffness,manufacturing and installation errors,component flexibility and The rigid-flexible coupling dynamic model of the transmission system under the action of the high-speed gyro effect is solved by numerical methods,which provides a theoretical basis for the study of the inherent characteristics,dynamic response and load sharing characteristics of the closed differential planetary transmission.The specific research contents are as follows:1.Combining the finite element idea and the concentrated mass method,with the help of the space beam theory,the components of the aerospace closed differential planetary gear train are equivalent to shafting units with various coupling relationships,and the equivalent process of components such as flexible pins is introduced.Furthermore,the coupling relationship between the shaft segments in the system is further analyzed,and the overall dynamic model of the transmission system under the simultaneous action of the sun gear floating,the flexible pin shaft and the flexible inner gear ring is established.2.According to the analysis of system parameters,the excitation parameters such as the time-varying meshing stiffness and the comprehensive meshing error of eachgear pair in the system are solved,and the natural frequency of the system is obtained according to the principle of solving the inherent characteristics,and the different load balancing measures are compared.Changes in the natural frequency of the system.3.Using numerical methods,the dynamic model of the aviation enclosed differential planetary transmission with the floating sun gear,the flexible pin shaft and the flexible inner gear ring established above is solved,and the steady-state vibration response of each gear node and two stages are obtained.The time domain response of the internal and external meshing force and the frequency domain response of the meshing force are analyzed.4.Based on the two-stage dynamic meshing force obtained above,the two-stage dynamic load factor of the system under steady-state conditions is calculated,and the dynamic load-sharing performance of the system under the combined action of different load-sharing measures is discussed.In addition,the flexibility of the ring gear is also studied.The influence of flexible pin structure flexibility and working condition parameters on the two-level load sharing performance of the system. |
PDF Full Text Request