Patent ID: 8739951

Claim:
A transmission device comprising: a first clutch; and a second clutch that is disposed circumferentially inward of the first clutch so as to overlap with the first clutch as viewed from a radial direction, wherein the first clutch includes a first clutch drum, a first clutch piston that is axially movable by hydraulic pressure supplied to a first engagement side oil chamber on an inner circumferential side of the first clutch drum, and a first cancel plate that defines together with the first clutch piston a first cancel oil chamber that cancels centrifugal hydraulic pressure; the second clutch includes a second clutch drum, a second clutch piston that is axially movable by hydraulic pressure supplied to a second engagement side oil chamber on an inner circumferential side of the second clutch drum; the first engagement side oil chamber and the second engagement side oil chamber overlap at least partially as viewed from a radial direction; the first clutch drum axially extends and includes a ring-shaped fixing portion provided between the first engagement side oil chamber and the second engagement side oil chamber in a radial direction; and the first cancel plate is fastened between the first clutch drum and the second clutch drum by the fixing portion.