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:
Jun. 18, 2013
Filed:
Feb. 06, 2009
Markus Herrmann, Scheidegg, DE;
Anton Fritzer, Markdorf, DE;
Markus Herrmann, Scheidegg, DE;
Anton Fritzer, Markdorf, DE;
ZF Friedrichshafen AG, Friedrichshafen, DE;
Abstract
A hydraulic control system for controlling a variable fluid volume flow to a consumer (), for example a flow of cooling oil to a wet-operating clutch, with a hydraulically pilot-controlled control valve connected to a fluid supply. The first control valve () is designed such that, in the absence of any pilot control pressure (pVST), the valve delivers a specified initial volume flow (Q) and, as the variable pilot control pressure (pVST) increases, the valve delivers a continuously increasing volume flow (Q). At least one second, independent, also hydraulically pilot-controlled valve () is designed such that this valve is activated in a specified range () of the variable pilot control pressure (pVST).