Dynamic Analysis of Gear Rattle under Pre-selection Strategy of Dual Clutch Transmission

Dual clutch transmission（DCT） has the characteristics of no power interruption and smooth shifting. However, the gear rattle phenomenon of DCT is more obvious after pre-selection. Taking a wet dual clutch transmission as the research object, without considering the shifting process of the transmission, the dynamic models of gear rattle in the 1st gear without pre-selection and preselect the 2nd gear are established respectively. In the model, the drag torque of each loose gear includes the drag torque of oil churning, bearing and synchronizer. In addition, the drag torque generated by the clutch in the non-power flow of the transmission is also considered. Based on considering the elastic contact of tooth surface, the gear contact model takes into account the nonlinear oil film force caused by lubrication effect. Runge-Kutta algorithm is used to solve the model, and the dynamic response of each gear pair is obtained. The feasibility of the dynamic model is verified by bench test, and the calculated results are in good agreement with the experimental results. The dynamic response of transmission gear is studied. The results show that the loose gear of transmission has obvious double-sided rattle phenomenon under certain angular acceleration excitation; pre-selection will not affect the gear pair that has been rattled without preselected gear, but after preselected gear, the non-power flow branches of the transmission will change, and the number of loose gears in the transmission will increase, which makes the rattle phenomenon of the transmission more obvious.