Research On Key Design Technology Of Multi-axis High-speed Gear Transmission System

The research object of this dissertation is the multi-shaft high-speed gear transmission system,which is used to fulfill performance test the performance of various auxiliary pumps in the service of aero-engine.The power and speed requirements of each output point of the gear transmission system are different,and there are strict requirements for the size,weight and rotary inertia of the shaft system.The maximum speed should be increased from zero to more than 30,000 revolutions per minute in 10 seconds.The study herein is of great significance for the development of China's aerospace industry.Based on the basic characteristics and design requirements of aero-engine test bed,using nonlinear time-varying gear meshing theory,a multi-shafting gear-bearing-rotor dynamics model was established,and the dynamic equations including transmission error,assembly error,tooth side clearance and time-varying mesh stiffness were obtained.Furthermore,based on meshing theory,optimization design,rotor dynamics,response spectrum analysis method,time-domain dynamic response analysis method,modal analysis method,modern testing theory and signal processing method,the multi-axis high-speed gear transmission system was designed and analyzed in detail.The main contents and research methods were as follows:1)According to the design characteristics of multi-shafting high-speed gear transmission system,the mathematical model of nonlinear multi-objective optimization design was established,the multi-objective optimization design was carried out for the gear transmission system,and the design parameters satisfying the requirements was obtained.The basic parameters and characteristics of dynamic pressure sliding bearing were designed and analyzed using finite difference method.2)Based on the forming principle of gear,the curve equations of each section of the tooth profile were derived respectively,and the theoretical model and solid model of the tooth surface of the gear were generated.On the basis of the curve equation of tooth modification and the error curve equation of tooth profile,the accurate gear tooth surface model and solid model with three kind of errors and three type of modification methods were established.3)In accordance with the grating dynamic measurement method and the principle of multi-channel virtual instrument,the precise test and analysis of gear transmission error were completed.The test process was simulated by finite element method,and the simulation results were in agreement with the test data,and the accuracy of the model was verified.4)On the basis of the effects of shear,bending,torsion,axial force,gyroscipic effect and internal damping of the rotor shaft,as well as the effects of time-varying meshing stiffness,tooth clearance and transmission error of the gear pair,the dynamic model and differential equation of the rotor-dynamic pressure oil-film bearing-rolling bearing-gear dynamic system was established.Based on the energy numerical analysis method and the finite element method,the dynamic characteristics of the multi-shafting gear transmission system were analyzed,and the results of the two methods were compared.5)The transmission test of the multi-axis gear transmission system was carried out.The sound pressure levels at different positions of the gearbox at rated speed and the vibration velocity and displacement along the longitudinal,transverse and vertical directions of the gearbox housing were tested.The modal decomposition of the data was performed by Hilbert eigenfunction method.In addition,the vibration data of each output shafts of the gear transmission system were tested and compared with the theoretical values.