Research On Design Method Of Helicopter Transmission System

Transmission system is one of three helicopter key moving parts, delivering the power and speed of the engines to the rotor, tail rotor and attachments in a certain proportion, and is an indispensable power transmission part during output of turbo shaft engines. The helicopter's performance depends largely on transmission system, whose property will directly influence the helicopter's performance and reliability.This paper firstly summarized the common parts structure form and function characteristics of several helicopter drive system, compared and discussed the structural layout and characteristics of three different forms of transmission system by analyzing many types of helicopter transmission system of the domestic and foreign.Secondly, it analyzed one certain type helicopter gear transmission system, including structure feature, power allocation path, all gear reducer deceleration principle, and the influence on its performance to the change of structural parameters. And then according to analytical hierarchy process (AHP), it optimized this type of the helicopter gear transmission system through mathematical model by establishing reasonable multi-objective optimization function with satisfactory results.Then, based on the analysis of design task, it determined engine power allocation in different flight state, the transport mission spectrum, the layouts form, all reduction ratio of transmission and power delivering path of transmission mechanism, and introduced the main characteristics of RomaxDesigner modeling software, and also materials in modeling the shaft parts, gears and bearings .Finally, it modeled and checked the main reducer, tail shaft and tail reducer respectively by using RomaxDesigner software's function of parallel axis transmission modeling tools, vertical shaft driving modeling tools, planetary gear transmission modeling tools and bearing stress, deformation and life analysis tools. And also main shaft parts of reducer (including main shaft, supporting shaft and planet carrier) were modeled in CATIA, processed in PATRAN through meshing finite element and defining material attribute, and then analyzed by finite element solver FESolver to make static stress analysis and model analysis. Design results can meet the design requirements.