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:
May. 21, 2019
Filed:
Jun. 22, 2017
Zf Friedrichshafen Ag, Friedrichshafen, DE;
ZF FRIEDRICHSHAFEN AG, Friedrichshafen, DE;
Abstract
An electrohydraulic transmission control system having a parking lock valve by which a parking lock cylinder of a parking lock device can be charged with an actuation pressure adjustable in an operating-state-dependent manner by at least one pilot pressure adjustable in the region of an electrohydraulic pressure adjuster and/or one pressure source. Above a defined actuation pressure level, the parking lock valve is held in a defined operating state in which the actuation pressure can be applied to the parking lock cylinder. The actuation and pilot pressures can be applied to a valve device such that when the actuation and pilot pressure levels approximately correspond to one another, the region of the control system which conducts the actuation pressure is operatively connected, upstream of the parking lock valve, to a pressure region in the region of the valve device with a pressure lower than the defined actuation pressure level.