Abstract: Provided is an automatic transmission capable of reducing friction loss. The automatic transmission is provided with an input shaft (2) coupled with a sun gear (Sa), an output member (3), a first to third planetary gear mechanisms (4, 5, 6), a first engagement mechanism (C1) coupling the input shaft (2) with a ring gear (Rc) releasably, a second engagement mechanism (C2) coupling a carrier (Ca) with a carrier (Cc) releasably, a third engagement mechanism (C3) coupling the carrier (Ca) with a second coupling body (Rb-Sc) releasably, a fourth engagement mechanism (B1) fixing a first coupling body (Ra-Cb) to a transmission case (1) releasably, a fifth engagement mechanism (B2) fixing a sun gear (Sb) to the transmission case (1) releasably, and a sixth engagement mechanism (B3) fixing the ring gear (Rc) to the transmission case (1) releasably.

Abstract: An automatic transmission includes two clutches that are disposed such that they overlap in an axial direction and occupy different positions in a radial direction. Each of the two clutches includes a clutch drum, a piston that forms a working fluid chamber for which a portion of the clutch drum serves as a cylinder, a plurality of friction plates that engage the clutch drum, and a cancel oil chamber that is disposed on a rear face side of the piston and that cancels a centrifugal oil pressure that acts on the working fluid chamber.

Abstract: An automatic transmission that includes one clutch that includes a clutch drum; a piston that forms a hydraulic oil chamber using a part of the clutch drum as a cylinder; a plurality of friction plates that engage with the clutch drum; and a cancel oil chamber that is provided on a rear side of the piston and that cancels a centrifugal oil pressure that acts on the hydraulic oil chamber. Oil is supplied to the cancel oil chamber from a boss portion formed in the clutch drum on a radially inner side, and the oil is discharged from discharge holes formed in the boss portion to an outside of a hydraulic oil chamber side of the clutch drum.

Abstract: An automatic transmission that includes two adjacent clutches. 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.

Abstract: An automatic transmission that includes two clutches that are provided in mutually different positions in a radial direction while overlapping each other in an axial direction. The two clutches each include a clutch drum; a piston that structures a operating oil chamber while using a part of the clutch drum as a cylinder; a plurality of friction plates that engage the clutch drum; and a cancel oil chamber that is disposed on a back face side of the piston and that cancels a centrifugal hydraulic pressure acting on the operating oil chamber.

Abstract: An automatic transmission includes two clutches that are disposed such that they overlap in an axial direction and occupy different positions in a radial direction. Each of the two clutches includes a clutch drum, a piston that forms a working fluid chamber for which a portion of the clutch drum serves as a cylinder, a plurality of friction plates that engage the clutch drum, and a cancel oil chamber that is disposed on a rear face side of the piston and that cancels a centrifugal oil pressure that acts on the working fluid chamber.