| Planetary gear system is the power output structure of helicopter rotor shaft.Due to the influence of installation and manufacturing errors of components,the load sharing of each branch of planetary gear train is usually uneven,which affects the stability of gear transmission and reduces the reliability of gear system.In order to solve this problem,this paper takes the flexible ring gear of planetary gear train as the load sharing architecture.And takes the load sharing performance of planetary gear train as the research object to establish an engineering rigidflexible coupling dynamic model of planetary gear train considering the flexibility of inner gear ring.Considering various internal and external excitations of the system,the dynamic meshing force of the system is obtained by simulation method,and the load sharing characteristics of each meshing transmission branch of the planetary gear system are calculated.According to the installation structure characteristics of flexible gear planetary gear train,the data acquisition scheme in the load sharing test of planetary gear train is designed,and the load sharing performance experiment of flexible gear planetary gear train is carried out.The engineering experimental data processing software system has been developed,and the load sharing characteristics of the system have been analyzed.The specific content of this paper is as follows:Primarily,the theory of the rigid-flexible coupling model was introduced,and the differential equation of the flexible gear ring is analyzed.The planetary gear system’s natural frequencies and modal shapes were solved by finite element software.The meshing stiffness of the planetary gear system was calculated by the finite element method.The influence of the thickness of the flexible support shaft of the internal gear ring on the internal meshing stiffness of the planetary gear train was explored.Secondly,a digital three-dimensional solid model of planetary gear train with five planetary gears and inner gear structure of hollow support shaft was constructed in UG software.The multirigid-body dynamic model of planetary gear system was established by ADAMS,and the kinematic analysis of the model was carried out to verify the correctness of the planetary gear train model structure.Based on ensuring the structural rationality of multi-rigid-body dynamics model,the modal neutral file of inner ring gear with hollow support shaft was established by finite element software,and the planetary gear transmission configuration with rigid-flexible coupling structure was obtained by importing it into ADAMS.The model was simulated and analyzed.In the post-processing module,the dynamic meshing force of the system was extracted to solve the load sharing coefficient of the system.By using this model,the influence of planetary gear support stiffness,eccentricity error,solar wheel geometry eccentricity,input condition and inner ring hollow support shaft thickness on the load sharing characteristics of the system was explored.Then,based on the analysis of rigid-flexible coupling model,the dynamic load sharing experiment of planetary gear train was carried out.According to the installation and structural characteristics of flexible ring planetary gear train,the data sampling scheme of sticking the strain gauge on the back of the ring was designed by using the strain measurement method.In order to ensure the accuracy of the collected data,multiple sets of strain gauges are pasted on the back of the gear ring.The effects of different operating conditions and system parameters on the load sharing characteristics of the system were experimentally analyzed.The experimental results are compared with the simulation results.Finally,to quickly process and analyze the experimental data,a software system for processing the experimental data of planetary gear train and calculating the load sharing coefficient of each meshing transmission branch was developed using the modular design method.The software system includes three primary modules: pre-processing,main analysis and postprocessing.It automatically screens the experimental data,completes data filtering and saves the calculation results of load sharing coefficient through text or picture. |
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