The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 08, 2017
Filed:
Dec. 16, 2015
Zf Friedrichshafen Ag, Friedrichshafen, DE;
Christoph Margraf, Markdorf, DE;
Stefan Brom, Friedrichshafen, DE;
ZF Friedrichshafen AG, Friedrichshafen, DE;
Abstract
A hydraulic system for operating an automatic transmission for motor vehicles includes a hydraulic actuator for operating a clutch and a stop valve, whereas the actuator has a pressurizable actuating pressure chamber, which can be closed in a pressure-tight manner by means of the stop valve, such that the clutch pressure is maintained independent of the other pressures of the hydraulic system. The stop valve includes a closure device that is movable by means of a hydraulic control pressure (p_S) into a closed position, in which an actuating pressure chamber port, and thus the actuating pressure chamber, is closed by means of the closure device. The closure device is movable into an open position at least by means of the force of a spring, in which the actuating pressure chamber port is opened. Thereby, the stop valve features a shiftable locking device, by means of which the closure device can be fixed in the closed position.