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. 17, 2012
Filed:
Jun. 10, 2010
Yuichi Yoshikawa, Osaka, JP;
Hiroaki Kawasaki, Osaka, JP;
Kenji Sugiura, Osaka, JP;
Hiroshi Ueda, Kyoto, JP;
Hiroki Asai, Hyogo, JP;
Yuichi Yoshikawa, Osaka, JP;
Hiroaki Kawasaki, Osaka, JP;
Kenji Sugiura, Osaka, JP;
Hiroshi Ueda, Kyoto, JP;
Hiroki Asai, Hyogo, JP;
Panasonic Corporation, Osaka, JP;
Abstract
A rotoris rotatably disposed around a statorthat is provided with a plurality of magnetic poles. The inner circumferential face of the rotor is provided with a magneton whose face opposing the stator main magnetization is performed, and on whose face opposing the substrate FG magnetization is performed. The outer circumferential ends of the magnetic poles of the stator are provided with extended portionsandthat vertically extend from the magnetic pole base. A face of the substrate opposing the rotor is provided with a FG patternopposing the magnet. The FG pattern is disposed on an outer side in a radial direction of the outer circumferential face of the stator. When an angle formed by a straight line connecting a central position in the radial direction of the magnet and a central position in the radial direction of the FG pattern with respect to a central axis of a driving shaft is taken as θ, and an angle formed by a direction of the FG magnetization with respect to the central axis of the driving shaft is taken as A, 0 degree<A≦θ is satisfied. Accordingly, it is possible to improve the precision in detecting the rotational speed by reducing noise superimposed on the FG signal, while securing a high driving efficiency.