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:
Feb. 20, 2018
Filed:
Apr. 09, 2014
Zf Friedrichshafen Ag, Friedrichshafen, DE;
Thilo Schmidt, Meckenbeuren, DE;
Hans-Joachim Martin, Kressbronn, DE;
Hans-Juergen Bader, Mochenwangen, DE;
ZF Friedrichshafen AG, Friedrichshafen, DE;
Abstract
A valve system for controlling a system pressure control system, in particular a hydraulic control unit of an automatic transmission, includes a multi-stage system pressure valve, a pilot valve and a control valve with a control piston downstream from the pilot valve that governs the pressure at a differential area of the system pressure valve, depending on the pilot pressure. The pilot pressure/system pressure characteristic curve features a continuous development, and whereas, from a predefined pilot pressure, on the basis of a sudden change to the dependency of the change to the system pressure as a function of the change to the pilot pressure, the gradient of the system pressure as a function of the pilot pressure is significantly steeper than that prior to the predefined pilot pressure.