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. 03, 2005
Filed:
Mar. 18, 2003
Tadaharu Yokota, Kanagawa, JP;
Masakazu Kurata, Yokohama, JP;
Michiya Hiramoto, Yokohama, JP;
Yukio Sudo, Kanagawa, JP;
Tadaharu Yokota, Kanagawa, JP;
Masakazu Kurata, Yokohama, JP;
Michiya Hiramoto, Yokohama, JP;
Yukio Sudo, Kanagawa, JP;
Hitachi, Ltd., Tokyo-to, JP;
Abstract
A power steering system for a vehicle, comprises a steering shaft connected to a steering mechanism. A hydraulic power cylinder is provided for assisting a steering effort of the steering mechanism. A reversible pump is provided having first and second discharge ports which are respectively connected through first and second hydraulic lines with two hydraulic pressure chambers of the hydraulic power cylinder so that the two hydraulic pressure chambers are respectively provided with hydraulic pressures. A driving device is provided for driving the reversible pump to rightly and reversely rotate. A differential pressure regulating valve is disposed in the hydraulic circuit to maintain pressure at least in the first and second hydraulic lines at a level of atmospheric pressure or higher in an inoperative condition of the reversible pump.