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 a rotor frameof the rotor is provided with a magnetmagnetized to have alternately opposite polarities in a direction opposing the stator, and magnetized to have alternately opposite polarities in a direction opposing a substrate. The outer circumferential ends of the magnetic poles of the stator are provided with a first extended portionthat extends from a magnetic pole baseto a substrateside, and a second extended portionthat extends from the magnetic pole base to a side opposite the substrate side. A face of the substrate opposing the rotor is provided with a FG pattern. When a distance between an end of the rotor frame on the substrate side and the substrate is taken as A, a distance between an end of the first extended portion on the substrate side and the substrate is taken as B, and a distance between the end of the first extended portion on the substrate side and the magnet is taken as G, B≦A≦B+G 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.