Patent attributes
A clutch device for an automatic transmission, wherein a piston is disposed radially outwardly of a drum supporting frictional coupling elements, and cooperates with the drum to define a hydraulic pressure chamber, and a balancer is disposed on one side of the piston which is remote from the hydraulic pressure chamber, the balancer cooperating with the piston to define a canceling chamber. The clutch device is characterized in that: the drum has a stepped portion, and a shaft to which the drum is fixed has a flange portion; and the drum is fixed to the shaft such that the stepped portion of the drum and the flange portion of the shaft cooperate to define therebetween an oil sump, and the drum has an oil hole for communication between the oil sump and the canceling chamber.
