Patent ID: 8083627

Claim:
An automatic transmission, comprising first and second clutches provided at different radial positions so as to axially overlap each other, each of the first and second clutches including a clutch drum, a piston disposed in the clutch drum, a plurality of friction plates engaging with the clutch drum, a hydraulic oil chamber of the piston, a cancel oil chamber that is provided so as to face the hydraulic oil chamber with the piston interposed therebetween, and cancels a centrifugal oil pressure that is applied to the hydraulic oil chamber, a return spring that biases the piston toward the hydraulic oil chamber, and a cancel plate that forms the cancel oil chamber between the cancel plate and the piston, and receives a reaction force of the return spring, wherein a plate member that forms a cylinder portion of the hydraulic oil chamber is provided between the piston and the clutch drum of the first clutch that is located on an inner diameter side, and an oil passage that supplies an oil to the cancel oil chamber of the second clutch that is located on an outer diameter side is formed between the clutch drum and the plate member.