Title:
STEP MOTOR
Document Type and Number:
WIPO Patent Application WO/2005/002029
Kind Code:
A1
Abstract:
A step motor is disclosed which comprises a rotor having four magnetic poles, a first magnetic pole which is excited by a first coil, a second magnetic pole which is excited by a second coil, and a third magnetic pole which is excited by the first and second coils. A gap (d) between the first or second magnetic pole and the rotor is so set that there occurs a magnetic attraction between a magnetic pole of the rotor and the first or second magnetic pole, and a gap (D) between the third magnetic pole and the rotor is formed lager than the gaps (d). When such a step motor is used in a shutter driving unit of a camera or the like, the open/closed state of the shutter can be surely kept even when no current is applied.
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Inventors:
KAWAMOTO HISASHI (JP)
OISHI SEIICHI (JP)
OISHI SEIICHI (JP)
Application Number:
PCT/JP2004/009099
Publication Date:
January 06, 2005
Filing Date:
June 28, 2004
Export Citation:
Assignee:
SEIKO PRECISION KK (JP)
KAWAMOTO HISASHI (JP)
OISHI SEIICHI (JP)
KAWAMOTO HISASHI (JP)
OISHI SEIICHI (JP)
International Classes:
G03B9/02; G03B9/04; G03B9/10; G03B9/26; H02K1/14; H02K37/14; H02K37/16; (IPC1-7): H02K37/14
Foreign References:
| CH625646A5 | 1981-09-30 | |||
| JPS5980147A | 1984-05-09 | |||
| JP2001033844A | 2001-02-09 |
Attorney, Agent or Firm:
Katayama, Shuhei (6-1 Kyobashi 1-chom, Chuo-ku Tokyo 31, JP)
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