US4508988A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Permanent magnet motor stator for d.c. motors
Assignee: Kollmorgen Technologies Corp
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Filing: 1983-12-08
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Granted: 1985-04-02
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Expires: 2003-12-08
Abstract
Abstract In a permanent magnet commutator type D.C. servomotor having a wound iron core armature and a permanent magnet stator, the stator includes a uniquely formed annular yoke. The unique yoke includes a central opening and a plurality of permanent magnet pole pieces, which are securely held to arcuate magnetic material projecting into the opening and which are spaced equally from and about the axis of the yoke. The magnets and arcuate magnetic material form boundaries to accommodate the armature and also form a relieved area between the magnets designed for reduced field distortion. The radial thickness of the magnet pole pieces, the arcuate members of magnetic material and the radial thickness of the yoke are proportioned relative to each other and to the I.D. of the pole pieces at prescribed values to maximize the motor performance.
Inventors
- 👤 Leon G. Reiss
- 👤 Roy D. Schultz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 11:17
CPC Classifications
H; H02; H02K; H02K23/00; H02K23/02; H02K23/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
142 words
In a permanent magnet commutator type D.C. servomotor of the type having a wound iron core armature, wherein the improvement comprises: a permanent magnet stator core including an annular yoke having a central axial opening, and a plurality of permanent magnet pole pieces within said opening and spaced equally from and about the axis of said yoke, each of said pole pieces including an arcuate permanent magnet and an arcuate member of magnetic material intermediate said permanent magnet and said yoke, the adjoining ends of said arcuate magnets and said arcuate members of magnet material forming a relieved interpole area; wherein the ratio of the combined radial thicknesses of said arcuate permanent magnet and said arcuate member of magnetic material to the combined radial thickness of said arcuate permanent magnet, said arcuate member of magnetic material and said annular yoke is 0.44±20%.
Claim 2
Dependent Claim
142 words
In a permanent magnet commutator type D.C. servomotor of the type having a wound iron core armature, wherein the improvement comprises: a permanent magnet stator core including an annular yoke having a central axial opening, and a plurality of permanent magnet pole pieces within said opening and spaced equally from and about the axis of said yoke, each of said pole pieces including an arcuate permanent magnet and an arcuate member of magnetic material intermediate said permanent magnet and said yoke, the adjoining ends of said arcuate magnets and said arcuate members of magnet material forming a relieved interpole area; wherein the ratio of the combined radial thicknesses of said arcuate permanent magnet and said arcuate member of magnetic material to the combined radial thickness of said arcuate permanent magnet, said arcuate member of magnetic material and said annular yoke is 0.44±20%.
Claim 3
Dependent Claim
18 words
A servomotor, as recited in claim 1, in which said magnet stator has two permanent magnet pole pieces.
Claim 4
Dependent Claim
18 words
A servomotor, as recited in claim 1, in which said magnet pole pieces and said ratio is ##EQU3##
Claim 5
Dependent Claim
44 words
A servomotor, as recited in claim 1, in which the ratio of the combined radial thickness of said arcuate permanent magnet, said arcuate member of magnetic material and said annular yoke to the I.D. of said arcuate permanent magnets in said yoke is 0.39-5%+15%.
Claim 6
Dependent Claim
13 words
A servomotor, as recited in claim 1, in which said ratio is ##EQU4##
Claim 7
Dependent Claim
46 words
A servomotor, as recited in claim 1, 2, 3, 4 or 5, in which the ratio of the combined radial thickness of said arcuate permanent magnet and said arcuate member of magnet material to the I.D. of said arcuate permanent magnets in said yoke is 0.17±15%.
Claim 8
Dependent Claim
28 words
A servomotor, as recited in claim 1, 2, 3, 4, 5 or 6 in which said annular yoke and said arcuate magnetic material members are of one piece.
Claim 9
Dependent Claim
19 words
A servomotor, as recited in claim 1, 2, 3, 4, 5, 6 in which said annular yoke is tubular.
Claim 10
Dependent Claim
39 words
A servomotor, as recited in claim 1, 2, 3, 4, 5 or 6 in which said tubular annular yoke and said arcuate members are fabricated from a plurality of discs stacked one on the other in a laminated structure.
Claim 11
Dependent Claim
24 words
A servomotor recited in claim 1, 2, 3, 4, 5, or 6 in which said arcuate magnetic members are fastened to said annular yoke.
References Cited (Backward Citations)
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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) | 1988-04-01 | 1988-10-01 | 1989-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-01 | 1992-10-01 | 1993-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-01 | 1996-10-01 | 1997-04-02 | $7700.00 | Window Closed / Lapsed |