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:
Mar. 05, 1991
Filed:
Mar. 22, 1990
Albert Blatter, Highland, MI (US);
Robert E Davis, Linden, MI (US);
Vickers, Incorporated, Troy, MI (US);
Abstract
An electrohydraulic servovalve comprising a torque motor which receives an electrical signal and position a flapper of a spring tube and flapper subassembly between a pair of opposed nozzles to control a spool valve and includes a feedback spring connected to the flapper and to the spool of the spool valve. A method of obtaining torque motor air gap symmetry is provided which comprises forming the pole piece/magnet subassembly to provide a desired total pole air gap on both ends of the armature, forming the armature ends so that they are equal to the total pole gap minus twice the desired nominal air gap, assembling the torque motor before attaching the spring tube and flapper subassembly, positioning the spring tube and flapper subassembly and the pole piece/magnets in a relative position to one another, providing spacers between the lower edges of the armature and the gap of the pole pieces, providing wedges between the upper surfaces of the ends of the armatures and the gap of the upper pole piece, providing a joint between the tube and the armature by a hardenable material to bond the armature and the spring tube, and permitting the joint to harden and set.