CLUTCH DEVICE OF AUTOMATIC SPEED CHANGE GEAR

摘要

PROBLEM TO BE SOLVED: To prevent obliquity to the axial line of a servo piston in a clutch having a structure that a clutch drum and a servo piston are axially superimposed on each other. SOLUTION: In the clutch device of an automatic speed change, a servo piston 4 axially pushing a friction member 3 supported by the clutch drum 1 from the opening end side of the clutch drum is radially superimposed with the clutch drum at least at an axial part. A plurality of protrusions 19 projecting from one of the peripheral face in the vicinity of the opening end of the clutch drum and the peripheral face of the servo piston and forming the contact part with the other peripheral face are circumferentially provided at a position where the both peripheral faces are positioned opposed to each other. The obliquity of the servo piston is regulated at a farther side from the support part of the servo piston by the contact through the protrusion. Hence, the clearance between the peripheral faces of the clutch drum and the servo piston is securely kept, and, the backlash distance between the servo piston and the clutch drum can be reduced.