Research Of Shift Control System Based On Selectable Overrunning Clutch

UST-Uninterrupted Shift Transmission is a novel kind of automatic transmission, whichcan implement automatic gearshift by reasonably combining the one-way transmission modeand the overrunning mode of Selectable Overrunning Clutch (SOC). Gearshift controls needto be deeply studied to make UST’s practical foundation solid. In this paper, a linkage shiftingdevice based on SOC for realizing uninterrupted power transmission during gearshift ispresented, which is one of the key techniques to make the UST practically applicable.A SOC may be a multi-mode type, including one-way and two-waytransmission/overrunning modes and so on, but the higher the number of mode is, the moredifficult to realize and apply will be. How to use the combination of simple two-mode SOCwith one-way transmission on/off or enable/disable functionality in UST gearing layout anddecrease the number of actuators, will be a good but challenging proposition.Therefore, based on the analyses of enable/disable modes of the simple two-mode SOC(roller type as an example), and on further combining gearshift control strategy for automaticgearbox as well as on transmission kinematics/dynamics, a linkage shifting device is designed.With the combination of SOC and actuators as few as possible, it can meet UST’s shiftingrequirements under various conditions. Meanwhile, a working model explanation about theUST with linkage shifting device in start-up, neutral, reverse and other common operationconditions is presented.CAE-Computer Aided Engineering verification with the simulation software SolidWorkshas shown that, the functionality of gearshift without power interruption can be achievedunder given conditions, and the main influence factors for shifting characteristics of thelinkage shifting mechanism are investigated, which is further confirmed by tests on theprototypes.Based on the sufficient demonstration of the feasibility of the linkage shifting device,dynamic models of automobile including UST or AMT-Automated Mechanical Transmissionare established. Simulation results show that automobile including UST has better powerperformance comparing with AMT. The linkage shifting device presented in this paper is a novel integrated shifting controlmechanism. It is based on the operation principles of SOC, UST’s gearshift and mechanicalinterlocker, and can fulfill reliable gearshifts while reduce the control difficulties of the wholesystem, i.e., it succeeds in using only simple two-mode SOC in the UST and controlling thegearshifts with only one actuator.