Research On Load-sharing Design Technology Of Flexible Gear Ring Of Planetary Gear Train

Planetary gear train has a series of advantages,such as high transmission ratio,high power density and strong bearing capacity.It has become an important transmission form in helicopter power transmission.However,the installation and manufacturing errors of its structural elements will cause uneven power transmission of each branch of planetary gear train,and further cause the bearing capacity decline,the life of planetary gears and the dynamic problems of impact vibration,thus seriously affecting the reliability and stability of helicopter transmission system.Therefore,it is significant to improve the load sharing performance of planetary gear train to adopt a flexible ring load sharing configuration which can compensate for the comprehensive errors of planetary gear train.However,due to the confidentiality of foreign technical data on the design of flexible ring structures with thin-walled sleeves,the domestic research on the impact of the flexible ring structure on the load sharing of the system is still not perfect.Therefore,this paper takes the planetary gear train of a helicopter main reducer with thin-walled sleeve inner ring as the research object,explores the influence of the flexibility of the ring on the dynamic load-sharing performance and system model of the planetary gear train,carries out the research on the dynamic load-sharing of planetary gear train with thin-walled sleeve inner ring,and provides theoretical support for the structure design of the ring.The details are as follows:1.Based on the multi-rigid-body discrete analysis method,the dynamic model of planetary gear train with thin-walled sleeve flexible inner ring structure is established.According to the knowledge of theoretical mechanics,the relevant parameters of flexible inner ring are calculated.According to Newton's second law,the dynamic equation of planetary gear train with flexible ring structure is established.The planetary gear train system is solved by numerical method.The influence of ring flexibility and ring sleeve thickness on the inherent characteristics of planetary gear train is further explored.2.The external meshing stiffness of the engagement of sun gear and planetary is calculated by the energy method.Based on the beam theory,the elastic deformation of the inner gear ring with thin-walled sleeve structure is analyzed.Then the formula for calculating the comprehensive internal meshing stiffness of the engagement of the flexible gear ring and planetary gear is determined,and the influence of the change of sleeve thickness on the internal meshing stiffness is analyzed.The dynamic load-sharing model of planetary gear train with flexible inner ring of wall sleeve was established,and the calculation formula of dynamic load-sharing coefficient was determined.The deformation of flexible inner ring of gear train,i.e.thin sleeve,and the influence of system parameters on the dynamic load-sharing of planetary gear train with flexible inner ring structure were analyzed.3.Based on the influence of the deformation of thin-walled sleeve on the dynamic load-sharing performance of planetary gear train,the three-dimensional modeling software was used to complete the modeling and assembly of planetary gear train with inner gear rings with different sleeve thicknesses.Then the stress and deformation of the planetary gear train were analyzed by Ansys Workbench software,and the torsional deformation was verified to be the main deformation form of the flexible gear ring,and the fatigue strength of the sleeve was obtained.Full coefficient;combined with the influence of sleeve thickness on load sharing and sleeve fatigue strength,the sleeve thickness was finally determined,and then the structure design of inner gear ring was completed.4.Experiments on dynamic load sharing of planetary gear train with three planetary gears are carried out.The strain stress of the sun gear and the inner gear ring is measured by the resistance strain measurement method.Then,according to the experimental principle of the load-sharing patch,the load-sharing coefficients of the internal and external meshing of the system are obtained,which verifies the rationality of the structure design of the thin-walled sleeve inner gear ring in this paper.Through the experiment,the influence of different parameters of the system on the load-sharing characteristics is analyzed,and the theoretical analysis is made.The conclusion is consistent,and the error between them is not more than 12%.