Lock-up damper device for torque converter

摘要

A lock-up damper device for a torque converter comprising a piston clutch plate slidable in axial direction and equipped with a friction facing pressed on a front cover and a driven plate interconnected to a turbine in between the front cover and the turbine. The piston clutch plate and the driven plate are coupled to each other, for relative rotation by torsion springs arranged longitudinal in circumferential direction of such plates. The torsion springs are installed at outer and inner peripheral parts of the plates. The torsion springs installed on the inner peripheral part of said plates is in contact at at least their radial outer peripheral, radial inner peripheral and side portions between said radial outer and inner peripheries with a wall of a concave portion formed on the piston clutch plate, and the torsion springs installed on the outer and inner peripheral parts are held by the drive plate secured to the piston clutch plate.