US 4,905,570 AGranted

Hydraulic power booster for a vehicle brake system

AssigneeAlfred Teves GmbH

InventorsHans-Dieter Reinartz, Helmut Steffes

Life of this patent

Estimating the term…

Loading patent…

Abstract

There is described a power booster for actuating a master brake cylinder having a booster piston which is axially movable in a cylinder bore and which, with its peripheral surface, confines a pressure chamber connectible to a hydraulic pressure source and, with an end surface, confines a booster chamber that is connectible with a pressure chamber via a first closable valve passage. Via a second closable valve passage, the booster chamber is connectible with a compensating chamber connected to an unpressurized reservoir. The compensating chamber is bounded by the peripheral surface of a reaction piston and by a sleeve that is formed fast with the housing and encompasses the reaction piston. The second valve passage is disposed in a central bore in the reaction piston terminating into the booster chamber. Arranged in the central bore is an actuating rod which carries a valve element for closing the second valve passage and which extends into the first valve passage in the booster piston. In the event of the reaction piston approaching the booster piston, the actuating rod opens the first valve passage after closing the second valve passage.

Claims8

Dependent claims

A hydraulic power booster for actuating a master brake cylinder of a vehicle brake system having an unpressurized hydraulic reservoir and a hydraulic pressure source, said hydraulic power booster comprising:

a booster housing having a cylindrical bore;
a booster piston axially movable within the cylinder bore and having a peripheral surface confining a pressure chamber and an end surface confining a booster chamber;
a first closeable valve passage connecting the booster chamber with the pressure chamber;
a second closeable valve passage connecting the booster chamber with the unpressurized hydraulic reservoir, wherein the first and second valve passages form a brake valve for regulating hydraulic pressure in the booster chamber;
and
a reaction piston projecting into the booster chamber and having a peripheral surface confining a compensating chamber communicating with the unpressurized hydraulic reservoir and a bore in the reaction piston connecting the second valve passage to the compensating chamber and the booster chamber, an actuating rod located in said reaction piston for movement toward and away from said booster chamber to close said second valve passage and open said first valve passage when said actuating rod is translated toward said booster chamber, and the reaction piston being sealed and guided in the cylindrical bore of the booster housing.

3 more elements

Dependencies are inferred from the claim text.