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. 01, 1985
Filed:
Dec. 12, 1983
Applicant:
Inventors:
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F15B / ;
U.S. Cl.
CPC ...
25112901 ; 13762565 ;
Abstract
A direct-acting servo valve wherein a spool is directly driven by a force motor including a coiled first bobbin located in a first magnetic circuit composed of a first yoke and a first magnet mounted on the yoke includes a second magnetic circuit composed of a second yoke and a second magnet located at one end of the spool, and a third magnetic circuit composed of third magnets and a magnetic member located at the other end of the spool. The second magnetic circuit serves as means for detecting the velocity of the spool, and the third magnetic circuit serves as means for detecting the displacement of the spool.