Clutch device for an automatic transmission

摘要

A clutch device, having a cam mechanism between a piston member and clutch discs, which has a high torque transmitting capacity, small dimensions and no engagement shock is provided. The clutch device comprises a pair of members which are spaced on a common axis and relatively rotate around a common axis, a variable length coupling member which is disposed on the common axis between the relatively rotating members and is composed of a pair of cam members, and a piston member which selectively pushes the variable length coupling member toward one of the relatively rotating members to cause a frictional engagement between one end of the variable length coupling member and one of the relatively rotating members. The variable length coupling member is elongated through the agency of a reaction between the cam members after a frictional engagement between one end of the variable length coupling member and one of the relatively rotating members caused by the piston member so that the relatively rotating members are engaged to each other by a force proportional to a transmitting torque input from one of the relatively rotating members.