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:
Dec. 06, 2011
Filed:
Oct. 24, 2008
Georg Gierer, Kressbronn, DE;
Thilo Schmidt, Meckenbeuren, DE;
Georg Gierer, Kressbronn, DE;
Thilo Schmidt, Meckenbeuren, DE;
ZF Friedrichshafen AG, Friedrichshafen, DE;
Abstract
An electrohydraulic control device () of an 8-speed transmission having several electrically controllable pressure control valves (-) for hydraulically actuating five switching elements (A-E) and an electric gear control unit via which different operating states of the transmission may be adjusted. Three of the switching elements are connected in the force flow of the transmission for representing a gear ratio ('1' to 'R') of the transmission. When the gear control unit is de-activated and the power supply to the solenoid valve and pressure control valves is interrupted, and when the transmission is in the operating state, in which a gear ratio (“1”; “2”; “3”; “4”; “5”; “6”; “7”; “8”; “R”) is engaged, a predefined emergency transmission (“6”; “R”) is represented by three simultaneously hydraulically connected switching elements (C, D, E, A, B, D).