Fork-less two-speed I-AMT with overrunning clutch for light electric vehicle

A novel two-speed inverse automated manual transmission (I-AMT) with overrunning clutch for electric vehicle (EV) is proposed in this paper. The structure of I-AMT is simplified because the synchroniser and shift fork are removed. During gear shifting, the overrunning clutch does not need to be controlled by an extra actuator due to its kinematic characteristics. Thus, the control issue involves only the inverse friction clutch. The control effect is further enhanced with a novel clutch actuator using worm gear and camshaft. The model of I-AMT with overrunning clutch is built in commercial software AMESim, and simulations are carried out to validate its performance. Lastly, the proposed I-AMT is manufactured and applied on a light EV. Results show that using overrunning clutch, the gear shifting can be completed in a short time without torque interruption or large oscillation. Furthermore, the proposed mechanism can avoid backward sliding during vehicle gears shifting on the slope. Compared with single-speed transmission, those with the proposed I-AMT perform better in energy saving and gradeability, especially in mountain areas.