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. 10, 2010
Filed:
Oct. 13, 2006
Georg Gierer, Kressbronn, DE;
Thilo Schmidt, Meckenbeuren, DE;
Anton Fritzer, Markdorf, DE;
Markus Herrmann, Scheidegg, DE;
Georg Gierer, Kressbronn, DE;
Thilo Schmidt, Meckenbeuren, DE;
Anton Fritzer, Markdorf, DE;
Markus Herrmann, Scheidegg, DE;
ZF Friedrichshafen AG, Friedrichshafen, DE;
Abstract
A valve assembly for controlling actuation of at least one starting clutch of an automatic transmission includes at least one clutch control valve through which a supply pressure is directed to a clutch actuation device, a pressure control valve controlled by a control device to supply at least one control valve of the valve assembly with a pilot pressure, a self-maintained hydraulic unit to maintain operation of an engaged starting clutch upon failure of the control device and loss of the pilot pressure. The valve assembly has a self-maintained valve and an activation valve. The self-maintained valve directs an activation pressure or control pressure, depending on the engine or transmission speed, to the activation valve. The actuation valve directs the activation to at least one clutch-regulating valve. The valve assembly also controls actuation or de-activation of the emergency operation function with a clutch actuation pressure.