Research On The Inlfuence Of Gear Parameters To The Dynamic Performance Of Automatic Transmission

Now research on automatic transmission is concentrated in the control systemsand hydraulic systems, while research on the planetary gear systems is less, andseldom involved the gears especially the gear parameters. The mechanicalproperties of the planetary gear systems especially the dynamic characteristics aredirectly related to the properties of the automatic transmission (vibration and noise,etc). And gear parameters greatly influence the dynamic performance of the gearsystems. So it is beneficial to improve the vibration and noise of the automatictransmission to study the gear parameters.A4-speed AT Simpson type planetary gear system was chose as the researchobject. Then a parametric model of the system was established based on CATIAsoftware, so that different modes of the Simpson system with different gearparameters can be quickly built by changing the basic parameters of gear (modulus,helix angle, modification coefficient, etc). Through the research on the dynamicperformance of the Simpson system with different gear parameters, the influence onthe inherent characteristics of the system by gear parameters and the influence onthe vibration of the system by the modification coefficient were obtained by theresearch.It is found that: the influence gear parameters variations on the inherentcharacteristics of the Simpson system are significant, and as module and helixangle increase, the natural frequency of the Simpson system gradually increases;the change of modification coefficient basically has no influence on the inherentcharacteristics; when module and modification coefficient changes simultaneously,the change of the inherent characteristics of the Simpson system depends on thechange of module; when helix angle and modification coefficient changessimultaneously, the change of the inherent characteristics of the Simpson systemdepends on the change of helix angle; modules on the influence of the inherentproperties of the system is stronger than helical Angle; gear parameters on theinfluence of the stiffness of the system is stronger than the influence of the mass ofthe system; as the modification coefficient increases, the vibration of the systemdecreases. In short, gear parameters have significant influence on the dynamicperformance of the planetary gear system of the automatic transmission system. Sovibration and noise of the system can be effectively reduced by the reasonableselection of gear parameters. These rules would provide reference basis for thedesign of the planetary gear, so as to domestic development of automatictransmission.