A clutch device for an automatic transmission.

摘要

A clutch device, having a cam mechanism between a piston means and clutch discs, which has a high torque transmitting capacity, small dimensions and no engagement shock is provided. A clutch device according to the present invention comprises a pair of members (2,4) which are spaced on a common axis and relatively rotate around a common axis, a variable length coupling means which is disposed on the common axis between the relatively rotating members and is composed of a pair of cam members and a piston means (1) which selectively pushes the variable length coupling means toward one of the relatively rotating members to cause a frictional engagement between one end of the variable length coupling means and one of the relatively rotating members. The variable length coupling means is elongated through the agency of a reaction between the cam members after a frictional engagement between one end of the variable length coupling means and one of the relatively rotating members caused by the piston means 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. <IMAGE>