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. 12, 1991
Filed:
Feb. 16, 1990
Ikumi Satoh, Iruma, JP;
Jun Nakano, Iruma, JP;
Riichiroh Harada, Iruma, JP;
Tatsuhiko Koba, Iruma, JP;
Kabushiki Kaisha Yasakawa Denki Seisakusho, Kitakyushu, JP;
Abstract
An electromagnetic actuator for a valve stem comprising a stator core having concentratedly wound coils around salient poles and the stator is positioned outside of a tubular member made of a nonmagnetic material. The electromagnetic actuator for a valve stem also has a rotor provided inside the tubular member for driving a threaded operating shaft such that it operats an objective member reciprocally an electromagnetic actuator for a valve stem is further constructed such that permanent magnets, alternately magnetized into a number of pole-pairs, are arranged along the surface of each salient pole of the stator core at a constant pitch, while a number of induction teeth are formed along the circumference of the rotor at a pitch equal to the pitch of the pole-pairs of the permanent magnets. The difference between the total number of the induction teeth and the total number of the polepairs of the permanent magnets is made equal to an even number. The rotor is rotated and the operating shaft is driven when an electromagnetic actuator for a valve stem operates as a pulse motor by alternating excitation of the coils.