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. 15, 2009
Filed:
Oct. 27, 2008
Hiroyoshi Teshima, Kyoto, JP;
Koji Muraoka, Kyoto, JP;
Akira Saiga, Kyoto, JP;
Nidec Corporation, Kyoto, JP;
Abstract
A rotor unit of a brushless motor includes a substantially cylindrical rotor magnet and a rotor holder arranged to retain an outer circumferential portion of the rotor magnet. A stator unit of the same includes a stator core around which coils are wound and a Hall IC for sensing magnetic flux generated from the rotor magnet. The stator core includes teeth disposed at positions separated in the circumferential direction, each of which has an arm portion extending outward in the radial direction around which the coil is wound, and a stretching portion extending from the arm portion outward in the radial direction and in the circumferential direction on both sides. A sensor element included in the Hall IC is positioned in the range within a lead angle of about four degrees or less as a mechanical angle in the circumferential direction from a line connecting radially the central axis and a point bisecting a line connecting neighboring stretching portions, and within a distance of about one millimeter or smaller outward in the radial direction from an arc connecting outer edges of the neighboring stretching portions.