US5654600A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motor with recess for index position detection
Assignee: Alps Alpine Co Ltd
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Filing: 1995-02-13
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Granted: 1997-08-05
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Expires: 2015-02-13
Abstract
Abstract The invention relates to a motor, and more particularly to a motor having means for detecting an index position. A rotor yoke of the motor is provided with a recess having a width greater than the width of each pole of a rotating magnet. Substantially the whole of one pole of the rotating magnet and a part of another pole adjacent to the one pole on the downstream side in terms of rotation of a rotor are exposed to the recess. The magnetic flux from the magnet exposed to the recess is detected by a Hall element disposed in opposition to the outer circumference of the rotor, thereby specifying the index position.
Inventors
- 👤 Tetsuya Nomura
- 👤 Hirokazu Nakagawa
- 👤 Kazuhiro Muramatsu
- 👤 Shigetoshi Kagomiya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:58
CPC Classifications
H; H02; H02K; H02K11/00; H02K11/20; H02K11/21; H02K11/215
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
249 words
A motor comprising: a stator, a rotor including a rotor yoke and a ring-shaped magnet mounted on the rotor yoke, the ring-shaped magnet having an outer periphery and being sectioned into a plurality of N poles and S poles having widths alternately arranged around the outer periphery, the rotor yoke having a side surface covering the outer periphery, said side surface of said rotor yoke defining a recess through which a part of said outer periphery of said ring-shaped magnet is exposed, and magnetic detecting means mounted on the stator and located adjacent said side surface of said rotor yoke for detecting a rotational position of a rotor by sensing magnetic flux emitted from the recess formed in said rotor yoke; wherein a width of said recess is greater than the width of one of said N poles and said S poles of said ring-shaped magnet, wherein an entire width of a first pole of said N poles and said S poles and a partial width of a second pole adjacent to said first pole on a downstream side of said rotor are exposed through said recess, and wherein said magnetic detecting means comprises a detecting element disposed adjacent said side surface of said rotor yoke for detecting a radial component of said magnetic flux generating from said ring-shaped magnet, and an amount of exposure of said second pole to said recess is set within 46% of the width of one of said N poles and said S poles.
Claim 2
Dependent Claim
249 words
A motor comprising: a stator, a rotor including a rotor yoke and a ring-shaped magnet mounted on the rotor yoke, the ring-shaped magnet having an outer periphery and being sectioned into a plurality of N poles and S poles having widths alternately arranged around the outer periphery, the rotor yoke having a side surface covering the outer periphery, said side surface of said rotor yoke defining a recess through which a part of said outer periphery of said ring-shaped magnet is exposed, and magnetic detecting means mounted on the stator and located adjacent said side surface of said rotor yoke for detecting a rotational position of a rotor by sensing magnetic flux emitted from the recess formed in said rotor yoke; wherein a width of said recess is greater than the width of one of said N poles and said S poles of said ring-shaped magnet, wherein an entire width of a first pole of said N poles and said S poles and a partial width of a second pole adjacent to said first pole on a downstream side of said rotor are exposed through said recess, and wherein said magnetic detecting means comprises a detecting element disposed adjacent said side surface of said rotor yoke for detecting a radial component of said magnetic flux generating from said ring-shaped magnet, and an amount of exposure of said second pole to said recess is set within 46% of the width of one of said N poles and said S poles.
Claim 3
Dependent Claim
227 words
A motor comprising: a stator, a rotor including a rotor yoke and a ring-shaped magnet mounted on the rotor yoke, the ring-shaped magnet having an outer periphery and being sectioned into a plurality of N poles and S poles having widths alternately arranged around the outer periphery, the rotor yoke having a side surface covering the outer periphery, said side surface of said rotor yoke defining a recess through which a part of said outer periphery of said ring-shaped magnet is exposed, and magnetic detecting means mounted on the stator and located adjacent said side surface of said rotor yoke for detecting a rotational position of a rotor by sensing magnetic flux emitted from the recess formed in said rotor yoke; wherein a width of said recess is greater than the width of one of said N poles and said S poles of said ring-shaped magnet, wherein an entire width of a first pole of said N poles and said S poles and a partial width of a second pole adjacent to said first pole on a downstream side of said rotor are exposed through said recess, and wherein said magnetic detecting means comprises a detecting element disposed adjacent said side surface of said rotor yoke for detecting a radial component of said magnetic flux generating from said ring-shaped magnet, and said recess has a nonrectangular shape.
Claim 4
Dependent Claim
227 words
A motor comprising: a stator, a rotor including a rotor yoke and a ring-shaped magnet mounted on the rotor yoke, the ring-shaped magnet having an outer periphery and being sectioned into a plurality of N poles and S poles having widths alternately arranged around the outer periphery, the rotor yoke having a side surface covering the outer periphery, said side surface of said rotor yoke defining a recess through which a part of said outer periphery of said ring-shaped magnet is exposed, and magnetic detecting means mounted on the stator and located adjacent said side surface of said rotor yoke for detecting a rotational position of a rotor by sensing magnetic flux emitted from the recess formed in said rotor yoke; wherein a width of said recess is greater than the width of one of said N poles and said S poles of said ring-shaped magnet, wherein an entire width of a first pole of said N poles and said S poles and a partial width of a second pole adjacent to said first pole on a downstream side of said rotor are exposed through said recess, and wherein said magnetic detecting means comprises a detecting element disposed adjacent said side surface of said rotor yoke for detecting a radial component of said magnetic flux generating from said ring-shaped magnet, and said recess has a nonrectangular shape.
Claim 5
Dependent Claim
14 words
A motor according to claim 2, wherein said nonrectangular shape comprises a trapazoidal shape.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-08-04 | 2001-02-03 | 2001-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-04 | 2005-02-03 | 2005-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-04 | 2009-02-03 | 2009-08-05 | $7700.00 | Window Closed / Lapsed |