Patent ID: 6716128
Filing Date: 2004-04-06
Classification: F16D,F16H

Abstract:
A clutch apparatus comprising:a clutch pack of clutch discs; a pressure member to compress the clutch pack axially for clutch engagement; a first piston to produce a clutch action to compress the clutch pack with the pressure member when the first piston is actuated by a first fluid pressure; a second piston arranged to be moved from a first position to a second position toward the clutch pack by the first piston when actuated, and further from the second position to a third position toward the clutch pack when the second piston is actuated; a friction reducing device, interposed between the second piston and the pressure member, to increase an axial distance between the pressure member and the second piston with the aid of a contoured cam surface when the second piston and the pressure member are rotated relative to each other, and thereby to push the pressure member to compress the clutch pack when the second piston is held at the second position; a shift stopper to prevent the clutch pack from being compressed when the distance between the pressure member and the second piston is not increased, by holding the second piston at the second position by limiting axial movement of the first piston; and a return spring to normally hold the second piston at the first position to prevent the clutch pack from being compressed irrespective of whether the distance between the pressure member and the second piston is extended or not.