JPS6479433A - Piston return mechanism for wet type brake - Google Patents

Abstract

PURPOSE:To make the whole body of a braking device compact by installing a rubber elastic member over the whole area of an end face of a piston, and its part extended to the outside of a peripheral edge of the piston is tightly attached to a wall part in and around the piston in an oiltight manner. CONSTITUTION:A peripheral edge of an elastic member 27 to be extended to the outside of the peripheral edge of a piston 26 is held between each presser ring 29 and a hub body 9, and hydraulic pressure to be fed to a hydraulic actuating chamber 25 is sealed and simultaneously the elastic member 27 by the hydraulic pressure to be fed to the hydraulic actuating chamber 25 is elastically deformed so that the piston 26 is driven, and, at the time of braking release, the piston 26 is returned by dint of elastic force of the elastic member 27. Consequently, an O-ring is made disusable owing to a simple structural piston driving mechanism, thus seal's durability is improvable. In addition, a piston return mehcanism can be simplified in structure and, what is more, wall thickness of the hub body in the car width direction is thinned, thus the whole axle device can made compact.