Gear Rattle Study Of Dual-Clutch Transmission Based On Torque Fluctuation

In recent years,vehicles equipped with wet dual-clutch transmission have sprung up,and the main problem of gear rattle noise appears.Because of the broadband characteristics of rattle noise,it is not only easy to make passenger uncomfortable in hearing,but also is mistaken for product failure.Therefore,the research on the rattle noise of the wet dual-clutch transmission has a strong practical significance.In this paper,the transmission system equipped with a wet dual-clutch transmission was studied by experiment and simulation.The reason why the transmission is prone to rattle was analyzed,and the idle gears that contribute a lot to the rattle noise was identified.Finally,the sensitivity analysis of the design and matching parameters to the rattle strength was used to provide a basis for further optimization.Firstly,the reasons and conditions of single gear rattle were analyzed.The structure of the wet dual-clutch transmission was introduced,and the power flow was studied.Combined with the conditions of single gear rattle,the cause of gear rattle of transmission and the idle gears that may have possibility to rattle were analyzed.Then,the wet dual-clutch transmission was studied by the vehicle test and the bench test.The speed range that was easy to rattle was 1400~1800r/min determined by the vehicle test.At the highest impact strength of the four.speed 1500r/min,the effect of the lubricating temperature,average torque,excitation frequency and torque fluctuation amplitude on the rattle strength were studied.The coherent analysis was introduced to calculate the contribution of each idle gear to the gear rattle of the transmission.It was concluded that the 3rd and 4th idle gear were always the main contribution source of the transmission gear rattle.Finally,the driveline system including the wet dual-clutch transmission was modeled and analyzed based on the AMESim software:1)For the single pair of gears,the evaluation indexes of gear rattle were studied,and the root mean square of the gear meshing power was selected as the gear rattle evaluation index.2)The modeling principles of inertia and stiffness in the driveline system were introduced,and some key components were modeled and illustrated,such as wet dual-clutch,idle gear,shift control module,etc.3)During model verification,the components on the power transmission path were verified by speed,and the other components were checked for energy index.4)The sensitivity analysis of design and matching parameters was calculated,and the conclusion is: 3rd idle gear backlash > Primary flywheel inertia > 3rd idle gear inertia > 6th idle gear backlash > 6th idle gear inertia > Second flywheel inertia > Flywheel stiffness.The conclusion provides direction and basis for further optimization.