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:
Aug. 02, 1983
Filed:
Apr. 04, 1980
Hiroyuki Yamauchi, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Abstract
A DC motor comprises a stator, a rotor adapted to rotate about an axis with respect to the stator, two coil windings mounted on one of the stator and rotor and separated by an electrical angle of N.times.90.degree. where N is an odd integer, a permanent magnet having a plurality of pairs of magnetic pole pieces of opposite polarity mounted on the other of the stator and rotor, a position magnet mounted on one of the stator and rotor for generating a sinusoidal magnetic flux signal, a magnetic reluctance element mounted on the other of the stator and rotor for detecting the sinusoidal magnetic flux signal and generating a control signal proportional to sin.sup.2 .theta. in response thereto where .theta. is an angle corresponding to the rotational position of the rotor, first and second amplifiers for producing drive signals proportional to sin.sup.2 .theta. and cos.sup.2 .theta., respectively, in response to the control signal, and a switching device for energizing one of the two windings with the drive signal proportional to sin.sup.2 .theta. and for energizing the other of the two windings with the drive signal proportional to cos.sup. 2 .theta. with the direction of current flow through the two windings being periodically alternated in correspondence with the rotational position of the rotor so as to rotate the rotor about its axis.