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:
Jun. 09, 1987
Filed:
Jul. 25, 1985
Fumio Tajima, Jyuo, JP;
Hiroshi Katayama, Yokohama, JP;
Kunio Miyashita, Hitachi, JP;
Teizo Tamura, Katsuta, JP;
Kenichi Hironaka, Hitachi, JP;
Takuro Kawano, Hitachi, JP;
Yosimi Sekita, Toukai, JP;
Kouichi Saito, Kitaibaraki, JP;
Akira Tamura, Toukai, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A permanent magnet electric machine such as, for example, a motor or generator, including a permanent magnet field member, an armature having salient magnetic poles and armature windings. A greatest common division of the number of magnetic poles of the field member and the salient magnetic poles having the armature windings differs from the number of magnetic poles. A group of grooves is formed between the salient magnetic poles having an interval of 2/3M.pi., with M being an integer which is not a multiple of three. To reduce the occurrence of cogging torque, auxiliary grooves are provided on the surface of the salient poles at positions which are spaced apart from positions of the grooves by (.pi./3)K+(.pi./6), in terms of electrical angle, with K being an integer.