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:
Sep. 20, 2011
Filed:
Dec. 16, 2009
Georg Gierer, Kressbronn, DE;
Thilo Schmidt, Meckenbeuren, DE;
Markus Herrmann, Scheidegg, DE;
ZF Friedrichshafen AG, Friedrichshafen, DE;
Abstract
A device for controlling a hydraulically operable switching element () of an automatic transmission of a vehicle with a position valve mechanism () having a main switch piston () which is spring biased into a first switch position and a second switch position with a pilot pressure (P_MV) which is adjustable through an electrically operated actuator (). An additional switch piston () and the main switch piston () are axially actuated in a valve housing (). Depending on the position of the pistons (), faces (A,A) of the respective pistons are either spaced apart or adjacent. The additional switch piston () is adjustable depending on a pilot pressure (p_K) of a switching element which engages a gear for forward drive.