Hydraulic brake system for vehicles

US5039175A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Roland Holzmann · Heubach, DE
• Guenther Schmidt · Tauberbischofsheim, DE
• Karl-Heinz Willmann · Glückstadt, DE

Key dates

• Filing date: Jun 22, 1990
• Grant date: Aug 13, 1991
• Expiry date: Jun 22, 2010

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S303/04
• WIPO field: Transport
• WIPO sector: Mechanical engineering

Abstract

A hydraulic brake system for a vehicle including, brake pressure modulators that prevent the locking of vehicle wheels caused by excessively high braking pressures. Such brake pressure modulators include brake line blocking valves and cylinders with pistons, where upon piston displacement, pressure fluid escapes from the wheel brakes to lower the brake pressure. The displacements of the pistons are controlled via valve assemblies that are connected to a servo pressure source. Failure of the servo pressure source, if there is even a small leak of a valve assembly, can lead to at least partial loss of a brake force during a braking event. To recognize and indicate any leak that might be present, a control unit which acts upon the valve assemblies is arranged such that it directs the valve assemblies into various switching positions and in this process, via a pressure sensor, observes whether logically observed pressures are varying impermissibly.