| High speed gear transmission systems are widely used in aviation,aerospace,navigation,power,transportation and chemical industries.The relative sliding speed between the gear pairs is very large,when the gear meshing,massive heat will be generated because of the tooth face friction.It will affect the lubrication performance and the anti-gluing capacity of the gear system.At the same time,hot deformation will be produced between the gear teeth,which affects the dynamic performance.Therefore,the research about the thermo-elastic coupling analysis and dynamic performance optimization of the high speed gear transmission system has important theoretical and practical value.This paper is focusing on high speed cone-cylindrical gear transmission system,the research includes caculation of temperature field,thermal elastic coupling analysis,nonlinear vibration characteristics and dynamic performance optimization of gear transmission system.The main research work in this thesis can be summarized as follows:(1)The flow field simulation model was established by using ANSYS/FLUENT software.Based on the hydrodynamic theory,transient characteristic simulation of gas liquid two phase flow field for oil spray lubrication was carried out.The convective heat transfer coefficient of gears was calculated.The friction heat flow of tooth surface was calculated by using Hertz contact theory and finite element contact method.On this basis,the steady temperature field simulation and transient temperature field simulation of gear pairs were carried out.And the gluing temperature was calculated according to the standard of ISO/TR 13989-1:2000.(2)The dynamic transmission error and dynamic meshing force of gear pairs was calculated using Ansys/LS-Dyna software.The thermoelastic coupling of gear system was analysed.The meshing stiffness of each gear pairs are cacultated considering the bulk temperature,and the influence of the bulk temperature to the meshing stiffness was study.At the same time,the influence of different loads and differrnt initial oil temperature was analyzed.(3)The dynamic model of high speed cone-cylindrical gear transmission system was established using the lumped parameter method.The dimensionless dynamic differentical equations are solved by 4-5 order variable step length Runge-Kutta method.And the effect of dimensionless frequency,gap,load and bulk temperature on the nonlinear dynamic characteristics were analysed.(4)On the basis of lumped parameter model of high speed cone-cylindrical gear transmission system,the anslytical expression of the vibration response of gear transmission system was obtained by harmonic balance method.A mixed discrete optimization model with objectives of minimizing RMS value of vibration acceleration and total mass was established by taking structural parameters of gear pairs as design variables,and the optimal design variables were obtained through the optimization program,based on the branch-bound algorithm. |
PDF Full Text Request