Patent US4341969A successfully refreshed from Google Patents.
US4341969A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Direct current motor with improved pole piece that reduces cogging
Assignee: Pacific Scientific Co
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Filing: 1980-12-01
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Granted: 1982-07-27
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Expires: 2000-12-01
Abstract
Abstract A direct current motor having pole pieces in the shape of partial cylinders each having an inner surface terminating in a leading and trailing edge. A series of notches are formed along the edges of the pole pieces so that each of the edges alternately slopes toward and away from the center of the inner arc surface of the pole piece.
Inventors
- 👤 Dale W. Sievert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:25
CPC Classifications
H; H02; H02K; H02K23/00; H02K23/02; H02K23/04; H02K2201/00; H02K2201/06
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
103 words
A permanent magnet direct current motor comprising in combination: a permanent magnet pole piece in the shape of a partial cylinder with an inner surface terminating in a leading edge and a trailing edge; an armature having a series of armature bars disposed around its periphery; means supporting said armature and said pole piece so that as said armature rotates said bars pass the edges of said pole piece; a series of notches formed in said pole piece along said leading and trailing edges so that each of said edges respectively alternately slopes toward and away from an armature bar passing under it.
Claim 2
Dependent Claim
103 words
A permanent magnet direct current motor comprising in combination: a permanent magnet pole piece in the shape of a partial cylinder with an inner surface terminating in a leading edge and a trailing edge; an armature having a series of armature bars disposed around its periphery; means supporting said armature and said pole piece so that as said armature rotates said bars pass the edges of said pole piece; a series of notches formed in said pole piece along said leading and trailing edges so that each of said edges respectively alternately slopes toward and away from an armature bar passing under it.
Claim 3
Dependent Claim
25 words
A permanent magnet direct current motor as in claim 1 wherein the depth of the notches is equal to the distance between adjacent armature bars.
Claim 4
Dependent Claim
16 words
A permanent magnet direct current motor as in claim 1 wherein said sloping edges are straight.
Claim 5
Dependent Claim
37 words
A permanent magnet direct current motor as in claim 1 wherein the slope of said edges sloping toward said armature bar is the same as the slope of said edges sloping away from the said armature bar.
Claim 6
Dependent Claim
35 words
A permanent magnet direct current motor as in claim 1 wherein the slope of said edges sloping away from said armature bar is different from the slope of said edges sloping toward said armature bar.
Claim 7
Dependent Claim
23 words
A permanent magnet direct current motor as in claim 1 wherein said pole piece and said notches are formed by a molding process.
Claim 8
Dependent Claim
72 words
A pole piece for a permanent magnet direct current motor comprising; a permanent magnet pole piece in the shape of a partial cylinder with an inner surface terminating in a leading edge and a trailing edge; a series of notches in said pole piece along said leading and trailing edges formed so that each of said edges respectively alternately slopes toward and away from the inner arc surface of said pole piece.
Claim 9
Dependent Claim
72 words
A pole piece for a permanent magnet direct current motor comprising; a permanent magnet pole piece in the shape of a partial cylinder with an inner surface terminating in a leading edge and a trailing edge; a series of notches in said pole piece along said leading and trailing edges formed so that each of said edges respectively alternately slopes toward and away from the inner arc surface of said pole piece.
Claim 10
Dependent Claim
21 words
A pole piece for a permanent magnet direct current motor as in claim 7 wherein said sloping edges are straight edges.
Claim 11
Dependent Claim
42 words
A pole piece for a permanent magnet direct current motor as in claim 8 wherein the slope of said edges sloping toward the center of said pole piece is the same as the slope of said edges sloping away from said center.
Claim 12
Dependent Claim
37 words
A pole piece for a permanent magnet direct current motor as in claim 8 wherein the slope of said edges sloping toward said center is different from the slope of said edges sloping away from said center.
Claim 13
Dependent Claim
27 words
A permanent magnet pole piece for a direct current motor as in claim 8 wherein said pole piece and said notches are formed by a molding process.
Claim 14
Dependent Claim
46 words
A direct current motor comprising in combination: a pole piece; an armature having a series of armature bars disposed around its periphery; means supporting said armature and said pole piece; and a series of notches formed in said pole piece along at least one edge thereof.
Claim 15
Dependent Claim
46 words
A direct current motor comprising in combination: a pole piece; an armature having a series of armature bars disposed around its periphery; means supporting said armature and said pole piece; and a series of notches formed in said pole piece along at least one edge thereof.
Claim 16
Dependent Claim
24 words
A direct current motor as in claim 12 wherein the depth of the notches is a function of the distance between adjacent armature bars.
Claim 17
Dependent Claim
21 words
A direct current motor as in claim 13 wherein said pole piece and said notches are formed by a molding process.
Claim 18
Dependent Claim
94 words
A direct current motor comprising in combination: a permanent magnet pole piece with its inner surface terminating in a leading edge and a trailing edge; an armature having a series of armature bars disposed around its periphery; means supporting said armature and said pole piece so that as said armature rotates said bars pass said edges of said pole piece; a series of notches formed in said pole piece along said leading and trailing edges so that each of said edges respectively alternately slopes toward and away from an armature bar passing under it.
Claim 19
Dependent Claim
94 words
A direct current motor comprising in combination: a permanent magnet pole piece with its inner surface terminating in a leading edge and a trailing edge; an armature having a series of armature bars disposed around its periphery; means supporting said armature and said pole piece so that as said armature rotates said bars pass said edges of said pole piece; a series of notches formed in said pole piece along said leading and trailing edges so that each of said edges respectively alternately slopes toward and away from an armature bar passing under it.
Claim 20
Dependent Claim
22 words
Direct current motor as in claim 15 wherein the depth of the notches is a function of distance between adjacent armature bars.
Claim 21
Dependent Claim
59 words
A pole piece for a direct current motor comprising; a pole piece with an inner surface terminating in a leading edge and a trailing edge; a series of notches in said pole piece along said leading and trailing edges formed so that each of said edges respectively alternately slopes toward and away from the center of said pole piece.
Claim 22
Dependent Claim
59 words
A pole piece for a direct current motor comprising; a pole piece with an inner surface terminating in a leading edge and a trailing edge; a series of notches in said pole piece along said leading and trailing edges formed so that each of said edges respectively alternately slopes toward and away from the center of said pole piece.
References Cited (Backward Citations)
US3469129A
Cited
US3663851A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-26 | 1986-01-25 | 1986-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-26 | 1990-01-25 | 1990-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-26 | 1994-01-25 | 1994-07-27 | $7700.00 | Window Closed / Lapsed |