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:
Nov. 14, 2000
Filed:
Aug. 14, 1998
Robert Spillner, Dusseldorf, DE;
TRW Fahrwerksysteme GmbH & Co. KG, Dusseldorf, DE;
Abstract
A apparatus for use with an open center steering valve (3) of a hydraulic power-assisted steering unit of a motor vehicle. The apparatus comprises an electric motor operated pump (5) and a hydraulic accumulator (7) for storing a pressurized quantity of hydraulic fluid. The hydraulic accumulator (7) is hydraulically connected to the pump (5). The pump (5) supplies the pressurized hydraulic fluid to the hydraulic accumulator (7). The apparatus further comprises a valve arrangement (10) for controlling hydraulic fluid flow from the hydraulic accumulator (7). The valve arrangement (10) has a riser (25), a slide valve (19), a valve seat (21), and an electromagnet. The riser (25) is hydraulically connected to the pump (5). The valve seat (21) has an opening which hydraulically connects the riser (25) and the hydraulic accumulator (7). The slide valve (19) is located within the electromagnet of the valve arrangement (10) and is movable by the electromagnet from a position blocking the valve seat opening and preventing hydraulic fluid flow from the accumulator (7) to the riser to a position clearing the valve seat opening and allowing hydraulic fluid flow from the accumulator (7) to the riser (25). The apparatus further comprises an electronic control unit (6) for controlling the electromagnet and the movement of the slide valve (19).