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:
Apr. 04, 2000
Filed:
Jul. 08, 1998
Toyoshige Sasaki, Yokohama, JP;
Chikara Aoshima, Zama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An electrical motor includes a cylindrical magnet divided into n regions circularly around at least an outer circumference thereof that are magnetized in alternate polarities. The motor also includes first and second coils arranged in an axial direction of the magnet. The magnet is interposed between the first and second coils. The motor further includes first and second external portions excitable by current flowing through the first and second coils, respectively, so that these portions become first and second external magnetic poles, respectively. The first and second external portions face the outer circumference of the magnet at one side and the other side thereof, respectively. The area of the first and second external portions facing the outer circumference of the first and second coils, respectively, is equal to or smaller than three-quarters of the area of the outer circumference of the first and second coils, respectively. The motor also includes first and second internal portions excitable by current flowing through the first and second coils, respectively, to cause these portions to become first and second internal magnetic poles, respectively. The first and second internal portions face the internal circumference of the magnet on the one and the other sides of the magnet, respectively.