US5289066A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stator for dynamoelectric machine
Assignee: Cadac Holdings Ltd
•
Filing: 1991-01-28
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Granted: 1994-02-22
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Expires: 2011-01-28
Abstract
Abstract A co-axial cylindrical brushless DC motor has an internal cylindrical stator and an external rotor containing permanent magnets. The cylindrical stator has a substrate of reinforced plastics covered by several layers of helically wound annealed steel wire of about 1 mm diameter to provide a cylindrical magnetic layer of soft magnetic material just below the wound poles on or adjacent the outer surface of the stator.
Inventors
- 👤 Peter B. Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 01:58
CPC Classifications
H; H02; H02K; H02K3/00; H02K3/04; H02K3/26; H02K1/00; H02K1/06; H02K1/12; H02K21/00; H02K21/12; H02K21/14; H02K21/22; H02K3/46; H02K3/47
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
182 words
A rotary dynamoelectric machine comprising: a generally cylindrical stator having a stator surface surrounded by a generally cylindrical external rotor rotatable about a rotational axis and having a generally cylindrical rotor surface facing said stator surface and being spaced apart therefrom by a generally cylindrical gap; a plurality of magnetic poles on said rotor surface facing said stator surface and positioned adjacent said generally cylindrical gap; wherein said stator has a generally cylindrical substrate of a first material having an outer surface and a thin annular cylindrical layer on said outer surface of said substrate, said annular cylindrical layer having an outer annular surface, a plurality of wound poles superimposed on said outer annular surface, so that the wound poles are adjacent said cylindrical gap and face said rotor, and at least a majority of the wound poles are positioned substantially parallel to the rotational axis of the rotor; and wherein said thin annular cylindrical layer is formed from one or more layers of an elongate material, said elongate material comprising a soft magnetic material having a magnetic permeability greater than 20.
Claim 2
Dependent Claim
182 words
A rotary dynamoelectric machine comprising: a generally cylindrical stator having a stator surface surrounded by a generally cylindrical external rotor rotatable about a rotational axis and having a generally cylindrical rotor surface facing said stator surface and being spaced apart therefrom by a generally cylindrical gap; a plurality of magnetic poles on said rotor surface facing said stator surface and positioned adjacent said generally cylindrical gap; wherein said stator has a generally cylindrical substrate of a first material having an outer surface and a thin annular cylindrical layer on said outer surface of said substrate, said annular cylindrical layer having an outer annular surface, a plurality of wound poles superimposed on said outer annular surface, so that the wound poles are adjacent said cylindrical gap and face said rotor, and at least a majority of the wound poles are positioned substantially parallel to the rotational axis of the rotor; and wherein said thin annular cylindrical layer is formed from one or more layers of an elongate material, said elongate material comprising a soft magnetic material having a magnetic permeability greater than 20.
Claim 3
Dependent Claim
23 words
A rotary dynamoelectric machine as recited in claim 1 wherein: said first material of said substrate is a substantially nonconducting, substantially nonmagnetic material.
Claim 4
Dependent Claim
40 words
A rotary dynamoelectric machine as recited in claim 1 wherein: said elongate material comprises a wire of small cross-section relative to its length, and the annular cylindrical layer is made up of a large number of turns of said wire.
Claim 5
Dependent Claim
28 words
A rotary dynamoelectric machine as recited in claim 1 wherein: said magnetic poles of the rotor are permanent and are closely spaced around the generally cylindrical rotor surface.
Claim 6
Dependent Claim
19 words
A rotary dynamoelectric machine as recited in claim 4 wherein there are between 6 and 20 permanent magnetic poles.
Claim 7
Dependent Claim
22 words
A rotary dynamoelectric machine as recited in claim 5 wherein said elongate material includes an annealed steel wire wound on said substrate.
Claim 8
Dependent Claim
31 words
A rotary dynamoelectric machine as recited in claim 6 wherein: said wire is wound on said substrate in at least one substantially helical layer to form said thin annular cylindrical layer.
Claim 9
Dependent Claim
31 words
A rotary dynamoelectric machine as recited in claim 7 wherein: said wire has a substantially circular cross-section and also has a diameter of between about 0.5 mm. and about 2.0 mm.
Claim 10
Dependent Claim
28 words
A rotary dynamoelectric machine as recited in claim 3 wherein: said magnetic poles of the rotor are permanent and are closely spaced around the generally cylindrical rotor surface.
Claim 11
Dependent Claim
19 words
A rotary dynamoelectric machine as recited in claim 9 wherein there are between 6 and 20 permanent magnetic poles.
Claim 12
Dependent Claim
22 words
A rotary dynamoelectric machine as recited in claim 10 wherein said elongate material includes an annealed steel tape wound on said substrate.
Claim 13
Dependent Claim
25 words
A rotary dynamoelectric machine as recited in claim 11 wherein said tape is spirally wound on said substrate to form said thin annular cylindrical layer.
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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) | 1997-02-21 | 1997-08-23 | 1998-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-02-21 | 2001-08-23 | 2002-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-02-21 | 2005-08-23 | 2006-02-22 | $7700.00 | Window Closed / Lapsed |