| Planetary gear train has the advantages of small volume,large transmission ratio,high transmission efficiency and high bearing capacity,and is widely used in vehicle engineering,ship power,aerospace,wind power and other fields.The characteristics of coaxial output of planetary gear train make this transmission mechanism become one of the important transmission forms of the final output of helicopter main reducer,with higher power density and larger power-to-weight ratio.However,at present,the traditional design method has been used to design the planetary gears of aviation helicopters,and each design and analysis is independent,which leads to long design cycle and low efficiency.Based on this,the paper adopts the concept of parametric design,and studies the structural parameter design and dynamic load sharing performance analysis technology of helicopter planetary gear train,which can not only shorten the design cycle,reduce material input and production cost,but also improve the design quality and efficiency.Specifically,the research focus of this paper is as follows:Firstly,based on the research of a helicopter planetary gear transmission system,this paper analyzes the design theory,strength design theory and tooth surface micro-geometric structure design method of helicopter planetary gear train with flexible gear ring,and designs the parametric structure of planetary gear train according to the design specifications and standards of aviation gear.Combined with the processing methods of data,charts and graphs,MATLAB software is used to develop programs,and the general program and subroutines are compiled.A set of programs which can input basic parameters and select the number of planetary gears can automatically complete design and calculation,and an integrated system is developed to realize strength analysis and tooth surface micro-geometric structure design of the designed gear train,and the existing load sharing performance system is integrated into the system to solve the load sharing coefficient of the designed planetary gear train.Secondly,the interface program is written in MATLAB and connected with ABAQUS.Through the secondary development of the simulation software ABAQUS,the parametric automatic modeling and assembly of helicopter planetary gear train can be realized.The program automatically imports the designed planetary gear train parameters into ABAQUS,and at the same time,ABAQUS is started to carry out three-dimensional modeling and finite element analysis of the model.Through the dynamic analysis of the helicopter planetary gear train,the displacement nephogram and stress nephogram of sun gear,planetary gear and internal gear are obtained.By comparing the simulation results with the theoretical calculation results of the system,the rationality of the micro-geometric structure design of the tooth surface is verified.Finally,based on the design of helicopter planetary gear train,the dynamic load sharing test of the designed planetary gear train is carried out.Because of the special structure of the helicopter planetary gear,the load-sharing test of the planetary gear train with flexible gear ring was carried out by using the strain gauge group measurement method,and more accurate sampling data was obtained by sticking the strain gauge at the tooth root of the gear ring.Five groups of strain gauges are designed at the root of the internal gear for accurately measuring the stress at the root of the internal gear.Two different working conditions are designed,and the load-sharing performance tests are carried out on a specific planetary gear test platform and data are collected.By processing and analyzing the original data,the load sharing coefficient of the system under two different working conditions is calculated,and the experimental calculation results are compared with the system calculation results,thus effectively verifying the rationality of the design.Through the design and experimental verification of helicopter planetary gear,the design results are optimized,which has certain application value for the selection of helicopter planetary gear transmission system. |
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