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:
Sep. 22, 2009
Filed:
Aug. 17, 2006
Yuji Enomoto, Hitachi, JP;
Akeshi Takahashi, Hitachi, JP;
Motoya Ito, Hitachinaka, JP;
Ryoso Masaki, Hitachi, JP;
Katsuyuki Yamazaki, Chiba, JP;
Masahide Yamazaki, Funabashi, JP;
Masashi Kitamura, Mito, JP;
Chio Ishihara, Tokyo, JP;
Kazuo Asaka, Matsudo, JP;
Shoji Ohiwa, Saitama, JP;
Yasuaki Motegi, Sano, JP;
Yuji Enomoto, Hitachi, JP;
Akeshi Takahashi, Hitachi, JP;
Motoya Ito, Hitachinaka, JP;
Ryoso Masaki, Hitachi, JP;
Katsuyuki Yamazaki, Chiba, JP;
Masahide Yamazaki, Funabashi, JP;
Masashi Kitamura, Mito, JP;
Chio Ishihara, Tokyo, JP;
Kazuo Asaka, Matsudo, JP;
Shoji Ohiwa, Saitama, JP;
Yasuaki Motegi, Sano, JP;
Hitachi Industrial Equipment System Co., Ltd., Tokyo, JP;
Japan Servo Co., Ltd., Tokyo, JP;
Hitachi Powered Metals Co., Ltd., Chiba-ken, JP;
Abstract
A three-phase permanent magnet brushless motor comprises a stator having three-phase windings, and a rotor having a permanent magnet with a plurality of poles for serving as a field magnet. The stator comprises a stator core which includes a powder core that is compacted at a high density in at least teeth thereof. A combination of the number of magnetic poles of the rotor with the number of slots of the stator satisfies a condition that a least common multiple of the number of slots and the number of magnetic poles is 60 or more in a region in which the number of magnetic poles is 16 or less, and the number of slots is 12 or less. The powder core is made by compacting magnetic powders to have a green density of 7.5 g/cmor higher.