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:
Feb. 05, 2008
Filed:
Mar. 09, 2005
Toshimitsu Sakaki, Kanagawa, JP;
Chiharu Nakazawa, Kanagawa, JP;
Tadaharu Yokota, Kanagawa, JP;
Masakazu Kurata, Yokohama, JP;
Toshimitsu Sakaki, Kanagawa, JP;
Chiharu Nakazawa, Kanagawa, JP;
Tadaharu Yokota, Kanagawa, JP;
Masakazu Kurata, Yokohama, JP;
Hitachi, Ltd., Tokyo-to, JP;
Abstract
A first fluid passage extends from a first outlet/inlet port of a hydraulic pump to a first work chamber of a power cylinder, and a second fluid passage extends from a second outlet/inlet port of the pump to a second work chamber of the power cylinder. A switch system switches the role of the first and second outlet/inlet ports in accordance with a turning direction of a steering wheel. Flow control mechanisms are respectively incorporated with the first and second fluid passages, so that a controlled flow of hydraulic fluid from the hydraulic pump to the first or second work chamber and vice versa are appropriately carried out thereby providing the driver with a comfortable steering feeling. A bypass arrangement may be provided between the first and second fluid passages to deal with a residual pressure that would be remained in the first or second work chamber when the hydraulic pump is under inoperative condition.