Patent ID: 8002663

Claim:
An automatic transmission, comprising: two adjacent clutches, wherein the two clutches each include: a clutch drum, a piston that structures an operating oil chamber with a portion of the clutch drum used as a cylinder, a plurality of friction plates that engage with the clutch drum, a cancel oil chamber that is arranged on a back surface side of the piston and that cancels a centrifugal oil pressure acting on the operating oil chamber, and a return spring that is provided within the cancel oil chamber and that is structured between a cancel plate and a back surface of the piston and that biases the piston toward the operating oil chamber, wherein: the cancel plate of one clutch among the two clutches and the piston of the other clutch among the two clutches are arranged so as to oppose an energizing force of the return spring of the two clutches, the cancel plate of the other clutch among the two clutches is disposed retained by a holding member with respect to the one clutch among the two clutches, the return spring of the one clutch among the two clutches has an energizing force that is stronger than that of the return spring of the other clutch among the two clutches, and the clutch drum of the other clutch among the two clutches is disposed retained with respect to an oil pressure acting direction of the cancel oil chamber of the one clutch among the two clutches with the energizing force of the return spring of the one clutch among the two clutches.