Research On Dynamic Characteristics Of High-power Planetary Gear System Based On Thermo-elastic Coupling Modification

The research subject of the dissertation stems from The National Natural Science Foundation project,“The study of load sharing mechanism and configuration of super high power wind power gearbox with multi planet gear and flexible pin”(51405048).The planetary gear system has many advantages,such as compact structure,large transmission ratio,power diversion,and it can realize the synthesis and decomposition of motion.It is widely used in many national major equipment engineering fields,such as ship transmission,wind power generation,nuclear power equipment,ocean platform,and so on.In order to adapt to the large-scale development of the equipment,the planetary gear transmission system is also developed towards the direction of high power and heavy load.At the same time,planetary gear system has complex structure,and the nonlinear factors of the system are rich.Under high power conditions,the thermal deformation that can not be neglected will aggravate the vibration and meshing impact of the planetary gear transmission systerm.In this thesis,a high power planetary gear transmission system was taken as the research object.Aiming at the problems of meshing impact and vibration,the modification design of the planetary gear system under the influence of thermo-elastic coupling and mesh misalignment was carried out.Through the thermal-elastic coupling contact analysis,the meshing stiffness and transmission error analysis with profile deviations,the dynamic characteristic analysis of the planetary gear system and the response surface model analysis,the influences of the modification parameters under thermal-elastic coupling on the dynamic characteristics of the planetary gear were analyzed.And the optimal modification parameters were obtained by the optimization design.The main contents of this dissertation are shown as follows:1)On the bases of the theory of planetary gear system transmission,structure parameters,modification principle and tooth surface temperature field analysis theory,a thermal-elastic coupling analysis model of planetary gear system was established.Appropriate modification parameters were selected.In order to determine the meshing impact situation,the load distribution of the system tooth surface was obtained,and the temperature field distribution of the tooth surface was obtained.Under the circumstanceof thermal-elastic coupling,the influences of the load distributions and the temperature field distributions of the internal and external meshing pairs caused by tooth profile and lead modification parameters were analyzed.2)The distribution of profile deviations caused by temperature field,tooth profile modification,tooth lead modification and shaft disalignment were derived.The meshing stiffness and transmission error analysis model of spur gear with profile deviations was established.The influences of thermal-elastic coupling factor and the influences of tooth profile and lead modification parameters under the circumstance of thermal-elastic coupling on the mesh stiffness and transmission error of the internal and external meshing pairs were analyzed.3)A dynamic analysis model of planetary gear system was established.Considering the meshing stiffness and transmission error as incentives of the system,the influence of thermal-elastic coupling factor on dynamic characteristics of the system were analyzed.And the influences of tooth profile and lead modification parameters under thermal-elastic coupling on dynamic characteristics of the system were studied.4)The response surface method was introduced into the dynamic characteristic optimization analysis of planetary gear system.According to the analysis results of dynamic characteristics under thermal-elastic coupling,appropriate objective function,design variables and parameters design of the response surface were selected,and a dynamic optimization analysis model of planetary gear system based on response surface method was established.The optimization objective was selected,and the optimal modification parameters combination was obtained.