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. 20, 2012
Filed:
Dec. 01, 2009
Masafumi Sakamoto, Gumma, JP;
Yoji Unoki, Gumma, JP;
Toru Kobayashi, Gumma, JP;
Nidec Servo Corporation, Gunma, JP;
Abstract
A permanent-magnet rotary electric machine preferably includes a stator and a rotor opposed thereto via an air gap. The stator includes a stator core having 4m (m is an integer equal to or larger than 2) main poles each having inductor teeth at a tip thereof. The rotor includes two rotor units adjacent to each other in the axial direction. Each rotor unit includes a pair of rotor magnetic poles and a permanent magnet arranged therebetween. The permanent magnets in the rotor are axially magnetized in opposite directions to each other. Each rotor magnetic pole has magnetic teeth on its outer periphery at a regular pitch. The rotor magnetic poles in each rotor unit are arranged such that the magnetic teeth of one rotor magnetic plate are offset by half a pitch from those of the other rotor magnetic pole, and the magnetic teeth of adjacent rotor magnetic poles are aligned with each other in the axial direction. The tooth pitch of the inductor teeth of each stator main pole is different from that of the magnetic teeth of the rotor magnetic pole to generate a fourth harmonic component of a permeance between the stator and the rotor zero.