Patent ID: 8439782

Claim:
An automatic transmission comprising: an input shaft rotatable by power from a driving source; a transmission unit capable of changing a speed of rotation of the input shaft to any one of a plurality of speeds at gears, the transmission unit comprising at least one planetary gear mechanism having three elements of a sun gear, a carrier, and a ring gear, one element among the three elements comprising a transmission-unit output element to transfer the power, another element among the three elements comprising a motor connection element to receive power from a motor, the motor connection element being rotated at an equal speed or a lower speed compared with the input shaft at all the gears; an output member to output the power transferred from the transmission-unit output element with a speed changed by the transmission unit; and a transfer mechanism to switch between a transfer state at which a transfer of power is performed between the motor connection element and the output member and an open state at which the transfer is not performed, the transfer mechanism being in the transfer state in a low-speed gear range from a first gear to a specific medium-speed gear among the gears to establish each of the gears in the low-speed gear range and in the open state in a high-speed gear range exceeding the specific medium-speed gear.