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:
Apr. 02, 1991
Filed:
Sep. 21, 1987
Robert D Vanderlaan, Kalamazoo, MI (US);
Pneumo Abex Corporation, Boston, MA (US);
Abstract
Limited angle torque motor includes a secondary magnetic flux path of relatively small cross-sectional area which increases the rotational and torque gains of the motor in a localized area about the motor null as if the magnetic air gap of the motor were substantially reduced so that when properly matched with a direct drive valve having significant valve overlap, a desired linear valve flow gain can be achieved. As the motor flux increases with applied current, the secondary flux path saturates, whereby further increases in current above a specified level are directed into the main pole structure magnetic flux path as if the secondary flux path did not exist. In one form of the invention, the desired secondary flux path is formed by providing the main magnetic pole structures with one or more small sections which span the magnetic air gap, whereas in another form of the invention, such secondary flux path is provided by placing a magnetic shim against the end faces at one or both ends of the magnetic housing.