Power brake unit
AssigneeITT Industries, Inc.
InventorJuan Belart
Life of this patent
Estimating the term…
Abstract
A power brake unit for automotive vehicles comprising a brake valve through which pressure-transmitting fluid is metered from a fluid source into a booster chamber to actuate a booster piston. A hydraulic transmission ratio provided by an input piston connected to a brake pedal and an operating piston connected to the brake valve reduces the pedal actuating travel when the fluid source is intact and is ineffective in the event of a failure of the fluid source. Only non-boosted forces are transmitted through the hydraulic transmission ratio. Should the fluid source fail, the hydraulic transmission ratio is rendered inoperative in a simple and safe manner.
Claims20
A power brake unit for automotive vehicles comprising:
- a housing having a longitudinal axis and a longitudinal bore coaxial of said axis;
- a booster piston disposed in a slidably sealed relation in said bore coaxial of said axis;
- an annular piston disposed in a slidably sealed relation in said bore coaxial of said axis having one end thereof spaced from an adjacent end of said booster piston;
- a brake valve disposed coaxially of said axis within said booster piston to meter pressure-transmitting fluid from a pressure source into a booster chamber disposed between said one end of said annular piston and said adjacent end of said booster piston, said fluid in said booster chamber acting on said booster piston in an actuating direction and on said annular piston in a direction opposite said actuating direction;
- an input piston connected to a brake pedal disposed in a slidably sealed relation in said bore coaxial of said axis in a spaced relation with the other end of said annular piston;
- and
- an operating piston connected to said brake valve disposed coaxial of said axis within said other end of said annular piston;
- said input piston and said operating piston providing therebetween a hydraulic transmission ratio to reduce actuating travel of said brake pedal when said pressure source is intact, said transmission ratio being ineffective in the event of failure of said pressure source, the diameter of said input piston being greater than the diameter of said operating piston and the diameter of said annular piston being no smaller than the diameter of said input piston.
Dependencies are inferred from the claim text.