Pressure holding valve

US5233910A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Martin Laichinger · Großenhain, DE
• Martin Scheffel · Leinfelden, DE

Key dates

• Filing date: May 14, 1992
• Grant date: Aug 10, 1993
• Expiry date: May 14, 2012

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T137/86887
• WIPO field: Transport
• WIPO sector: Mechanical engineering

Abstract

A pressure holding valve for pressure-fluid-actuated leveling systems in vehicles, having at least one seat valve with a valve opening, a valve seat and a valve member in which the valve member is opened by a control piston acted upon by pressure fluid. In order to achieve an absolutely pressure-tight seat valve with a long service life, an elastomer seal which seals off from the valve member is disposed on the valve seat, and pressure equalizing means are provided such that upon an impingement of pressure on the control piston in an opening direction of the seat valve, pressure build up upstream of the valve member is such that only a slight pressure difference arises at the seal at the onset of opening. In addition, the valve member is embodied such that upon displacement in a closing direction of the seat valve, the valve member substantially closes the valve opening in advance of the valve member becoming seated upon the seal.