Device for increasing the functional reliability of a hydraulic circuit of a hydraulically operable clutch

US7419456B2 · kind B2 · utility

Assignee

• ZF FRIEDRICHSHAFEN AG · DE

Inventors

• Thomas Knoblauch · Saarburg, DE
• Christoph Rüchardt · Bodolz, DE
• Otto Ebner · Friedrichshafen, DE
• Klaus Schweiger · Friedrichshafen, DE
• Matthias Winkel · Weingarten, DE
• Andreas Schwenger · Friedrichshafen, DE
• Marcus Gansohr · Salem, DE

Key dates

• Filing date: Nov 26, 2003
• Grant date: Sep 2, 2008
• Expiry date: Mar 15, 2025

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16D2500/70406
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A known device for increasing the functional reliability for a hydraulic circuit of a hydraulic clutch having a pressure reservoir (25) and a release cylinder (5) which comprises a primary piston (14) and a secondary piston (16). A compensation volume is developed in the sense that when the vehicle is at a standstill and the parking brake released, an unintentional release of the clutch is prevented. A pressure-monitoring/pressure-supply device (28) is used for determining a reference operating pressure and establishes a static pressure which, in case of any system error, only allows displacement of the secondary piston (16) such that the contact pressure of the clutch discs, against one another, is still sufficient to maintain the vehicle at a standstill.