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. 31, 2004
Filed:
Mar. 28, 2002
Japan Servo Co., Ltd., Tokyo, JP;
Abstract
A permanent magnet motor comprising a permanent magnet and an armature having a plurality of winding grooves facing the permanent magnet with an air gap therebetween. The armature has a plurality of auxiliary grooves on a magnetic pole surface thereof, wherein a composite of two vectors of cogging torque generated by the auxiliary grooves is deviated by 180° or 120° from a vector of cogging torque generated by the winding grooves in the sixth harmonic plane, and wherein a width of a portion of an air gap magnetic flux density waveform that includes a value that is more than 90% of a peak value of the air gap magnetic flux density waveform is less than 80% or 86% of a width of a pole pitch portion of the air gap magnetic flux density waveform. Each vector of cogging torque generated by each of the plurality of auxiliary grooves is deviated by 180° or 120° from a vector of cogging torque generated by the winding grooves in the sixth harmonic plane, respectively, and wherein a width of a portion of an air gap magnetic flux density waveform that includes a value that is more than 90% of a peak value of the air gap magnetic flux density waveform is less than 80% or 86% of a width of a pole pitch portion of the air gap magnetic flux density waveform.