Automatic transmission mechanism

摘要

Sun gears of a single planetary gear unit and a dual planetary gear unit are connected with respect to each other, carriers of the respective gear units in the connected state are connected to an output member, an input member is connected to a ring gear of the single planetary gear unit through a first clutch, to a sun gear through a second clutch and also to a ring gear of the dual planetary gear unit through a third clutch, and the sun gear and a ring gear of the dual planetary gear unit are stoppable by retaining means. When in forward travelling, the ring gear of the single or dual planetary gear unit is inputted with torque from the input member based on connection of the first and/or third clutch.