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:
Oct. 13, 1998
Filed:
Jul. 02, 1996
Yukio Uchida, Atsugi, JP;
Norihiro Saita, Isehara, JP;
Unisia Jecs Corporation, Atsugi, JP;
Abstract
A flow control device or valve used in a power steering system of an automotive vehicle. The flow control device comprises a housing formed with an axially extending hole in which a spool valve is movably disposed. A first pressure chamber is defined in the hole, with one end of the spool valve. A drain passage is opened to the first pressure chamber and closable with the spool valve. A second pressure chamber is defined in the hole, with the other end of the spool valve. A restricting orifice is provided to be communicated with the first pressure chamber. An introduction passage is formed to be communicated through the restricting orifice with a discharge passage and opened to the first pressure chamber. The pressure in the discharge passage is introduced to the second pressure chamber. A first spring is disposed in the second pressure chamber to bias the spool valve in a direction to close the drain passage. A spring holding member is movably and coaxially disposed in the axially extending hole. The spring holding member has a first end face defining the second pressure chamber, and a second end face which is larger in pressure-receiving area than the first end face. The first spring is disposed between the spool valve and the first end face of the spring holding member. The second end face of the spring holding member defines a pressure control chamber communicated with the second pressure chamber. Additionally, a second spring is provided to bias the spring holding member in a direction to reduce a volume of the pressure control chamber.