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. 24, 1992
Filed:
Aug. 23, 1991
Herbert Handte, Filderstadt, DE;
Moog GmbH, Boblingen, DE;
Abstract
A two-stage flow-control electrohydraulic servovalve has a pilot-stage (14) and a second-stage valve spool (6) mounted for sliding movement relative to a body (1). The pilot-stage (14) is arranged to provide an output pressure, which is used to selectively displace the second-stage spool (6) relative to the body, to establish flow through the second-stage. The second-stage spool has a plurality of lobes, which are overlapped with respect to passageways communicating with the control ports (3,4). A spool position feedback servoloop is closed about the second-stage valve spool and the pilot-stage. The improvement provides a compensation circuit (21) for modifying the command signal (e.sub.c) so as to compensate for the 'dead zone' in the normal second-stage flow-to-displacement characteristics, such that the second-stage output flow will be substantially proportional to the command signal.