초록 ▼

A hydraulic wheel braking system for a vehicle includes wet disc wheel brakes that are applied by a single spring-activated piston within each brake housing. Each piston is selectively and variably disengaged from the brake discs by variable hydraulic pressure acting against the piston in opposition

A hydraulic wheel braking system for a vehicle includes wet disc wheel brakes that are applied by a single spring-activated piston within each brake housing. Each piston is selectively and variably disengaged from the brake discs by variable hydraulic pressure acting against the piston in opposition to spring pressure to enable controlled wheel rotation. During vehicle operation, brake fluid pressure at the pistons is controlled by a foot pedal-operated brake valve. A manually-operated parking and control valve assembly can selectively disable the brake valve and relieve hydraulic pressure at the pistons to spring-apply the pistons to the discs. The assembly acts to automatically spring-apply the pistons to the discs uopn a loss of brake or transmission clutch fluid pressure.

대표청구항 ▼

A wheel braking system for a vehicle comprising: brake housing for association with a vehicle wheel, rotatable wheel means extending into the brake housing, friction means movable into frictional interaction with the wheel means for retarding and stopping wheel rotation, braking means including ener

A wheel braking system for a vehicle comprising: brake housing for association with a vehicle wheel, rotatable wheel means extending into the brake housing, friction means movable into frictional interaction with the wheel means for retarding and stopping wheel rotation, braking means including energy storage means within the brake housing for applying a braking force to the friction means and moving the friction means into frictional interaction with the rotatable wheel means to retard and stop wheel rotation, fluid pressure-operated brake release means for applying a brake releasing force in opposition to the braking force applied by the braking means to release the friction means from frictional interaction with the rotatable wheel means, brake release operating means for selectively operating the brake release means and operable to control the magnitude of the brake releasing force to provide a controlled release of the friction means, the braking means comprising a brake piston means and the energy storage means comprising mechanical spring means, the brake release means comprising a fluid pressure chamber within the housing defined in part by the piston means such that fluid pressure applied to the piston means within the chamber urges the piston means away from the friction means in opposition to the spring means, the brake release operating means including a first manually operable brake valve means in a pressure fluid circuit for controlling the fluid pressure within the fluid pressure chamber and thereby the brake releasing force, and a second manually operable valve means operable in a first position to activate the first valve means and operable in a second position to deactivate the first valve means to prevent operation of the brake release means, wherein the second valve means includes a manually-operated park valve member and a pilot pressure-operated control valve member, the control valve member being operated by pilot pressure from a transmission clutch fluid pressure circuit.