US Patent 9303747 Lock-up device for torque converter

A lock-up device includes a clutch portion and a damper mechanism. The clutch portion includes a clutch output member, a clutch plate, an oil chamber plate having a disc shape and a piston. The oil chamber plate is disposed between a front cover and an inner peripheral part of a turbine, while being axially immovable with respect to the front cover. The piston is disposed between the front cover and the oil chamber plate while being axially movable. The piston forms a first oil chamber for lock-up actuation together with the oil chamber plate, and forms a second oil chamber for lock-up releasing together with the front cover.