US4006375A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stepping motor
Assignee: WEARNES TECHNOLOGY (PRIVATE) Ltd
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Filing: 1975-05-02
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Granted: 1977-02-01
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Expires: 1995-05-02
Abstract
Abstract A rotary stepping motor having high torque and low rotor inertia wherein the rotor is of a disk type configuration having a plurality of uniformly spaced rotor poles and the stator has a plurality of stator pole pairs which are formed in separate groups, the spacing between the stator poles in each group being equal to the rotor pole spacings and the spacings between the stator pole groups being not equal to the rotor pole spacings. The stator may be formed of laminated stator elements to provide a magnetic path with the laminations oriented so as to prevent delamination thereof due to the magnetic forces present during operation. The laminated stator elements are appropriately affixed to the motor housing so that the pole pieces thereof are maintained at preselected positions relative to a reference planar surface of the housing. The rotor poles may be tapered to further reduce the rotor inertia and increase motor speed operation.
Inventors
- 👤 Frank Lyman, Jr.
- 👤 William C. McDonald
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:40
CPC Classifications
H; H02; H02K; H02K37/00; H02K37/02; H02K37/08
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
197 words
A multiphase rotary stepping motor comprising housing means; a shaft; bearing means associated with said housing means for rotatably mounting said shaft; a rotor secured to said shaft, said rotor having a plurality of equally spaced pole pieces extending radially therefrom; a stator fixedly mounted to said housing means, said stator having N groups of pairs of pole pieces separated by gaps, said rotor pole pieces being rotatably movable through said gaps, each of said groups having at least one coil associated therewith so that corresponding groups of said rotor pole pieces are capable of developing flux paths with said groups of stator pole pieces upon passage of current in the coils of said stator pole piece groups; the stator pole pieces in each of said groups thereof being angularly spaced from each other by a spacing equal to the spacing of said rotor pole pieces and said stator pole groups being separated from each other by N spacings that are not equal to the spacings of said rotor pole pieces, (N-1) of said N spacings being equal to each other and the remaining one of said N spacings being greater than that of said (N-1) spacings.
Claim 2
Dependent Claim
197 words
A multiphase rotary stepping motor comprising housing means; a shaft; bearing means associated with said housing means for rotatably mounting said shaft; a rotor secured to said shaft, said rotor having a plurality of equally spaced pole pieces extending radially therefrom; a stator fixedly mounted to said housing means, said stator having N groups of pairs of pole pieces separated by gaps, said rotor pole pieces being rotatably movable through said gaps, each of said groups having at least one coil associated therewith so that corresponding groups of said rotor pole pieces are capable of developing flux paths with said groups of stator pole pieces upon passage of current in the coils of said stator pole piece groups; the stator pole pieces in each of said groups thereof being angularly spaced from each other by a spacing equal to the spacing of said rotor pole pieces and said stator pole groups being separated from each other by N spacings that are not equal to the spacings of said rotor pole pieces, (N-1) of said N spacings being equal to each other and the remaining one of said N spacings being greater than that of said (N-1) spacings.
Claim 3
Dependent Claim
25 words
A multiphase rotary stepping motor in accordance with claim 1 wherein portions of said coils are positioned in the spacings between said stator pole groups.
Claim 4
Dependent Claim
26 words
A multiphase rotary stepping motor in accordance with claim 1 wherein said coils are positioned at regions remote from the spacings between said stator pole groups.
Claim 5
Dependent Claim
15 words
A multiphase rotary stepping motor in accordance with claim 1 wherein said stator is laminated.
Claim 6
Dependent Claim
50 words
A multiphase rotary stepping motor in accordance with claim 4 wherein said laminations are oriented to form laminar planes at said gaps which are substantially perpendicular to the plane of rotation of said rotor pole pieces to prevent delamination thereof by the magnetic forces present during operation of said motor.
Claim 7
Dependent Claim
78 words
A multiphase rotary stepping motor in accordance with claim 4 wherein each of said groups of pairs of stator pole pieces includes at least one laminated stator element having a surface on which said stator pole pieces are formed; said stator further including means for mounting said laminated stator elements to said housing so that the pole pieces formed on each of said elements are at a preselected position relative to a reference planar surface of said housing.
Claim 8
Dependent Claim
94 words
A multiphase rotary stepping motor in accordance with claim 6 wherein each of said laminated stator elements has one planar surface which is spaced from the surface on which said pole pieces are formed, and said mounting means includes means for affixing said laminated stator elements to said housing so that said planar surface thereof is maintained in a tightly abutting relationship to said reference planar surface of said housing; whereby the faces of the stator pole pieces formed on said elements are maintained at a fixed position relative to said reference planar surface.
Claim 9
Dependent Claim
24 words
A multiphase rotary stepping motor in accordance with claim 7 wherein said affixing means comprises bolt means for clamping said element to said housing.
Claim 10
Dependent Claim
30 words
A multiphase rotary stepping motor in accordance with claim 8 wherein said elements are U-shaped and said bolt means clamps said element to said housing at the bight region thereof.
Claim 11
Dependent Claim
61 words
A multiphase rotary stepping motor in accordance with claim 7 wherein said affixing means includes a plurality of slots formed in said housing at the regions thereof where said elements are to be affixed, each of said laminated stator elements having a correspondingly shaped configuration for engagement with its associated slot to retain said elements at preselected positions in said housing.
Claim 12
Dependent Claim
26 words
A multiphase rotary stepping motor in accordance with claim 10 and further including means for locking each of said laminated stator elements in said retained positions.
Claim 13
Dependent Claim
59 words
A multiphase rotary stepping motor in accordance with claim 1 wherein said coils are adapted for sequential excitation in a selected direction about said stator; and the arrangement of said N spacings between each of said stator pole groups being such that as said coils are sequentially excited said rotor rotates in a direction opposite to said selected direction.
Claim 14
Dependent Claim
44 words
A multiphase rotary stepping motor in accordance with claim 1 wherein the total number of stator pole pairs is less than the total number of rotor poles and the spacings between said stator pole groups are greater than the spacings between said rotor poles.
Claim 15
Dependent Claim
64 words
A multiphase rotary stepping motor in accordance with claim 1 wherein the total number of stator poles is equal to the number of rotor poles, said (N-1) spacings between said stator pole groups being less than the spacing between said rotor poles and said remaining one of said N spacings between said stator pole groups being greater than the spacing between said rotor poles.
Claim 16
Dependent Claim
120 words
A multiphase rotary stepping motor in accordance with claim 1 wherein said rotor has R uniformly spaced pole pieces, the spacing between each of said rotor poles being defined as a unit space, each of said groups of stator pole pairs has A stator pole pieces, said (N -1 ) equal spacings between said stator pole groups being equal to (B+ -1/N ) where B is an integral number of said unit spaces, and said remaining one of said N spacings being equal to (C+ -1/N ) where C is an integral number of said unit spaces, the quantities A, B and C being selected in accordance with the following relationship: (N)A + (N-1)B + C = R + N-.sup.+1
Claim 17
Dependent Claim
16 words
A multiphase rotary stepping motor in accordance with claim 15 wherein N is equal to 5.
Claim 18
Dependent Claim
82 words
A multiphase rotary stepping motor in accordance with claim 16 wherein said rotor comprises twenty pole pieces angularly and uniformly spaced from each other by 18°; and said stator comprises fifteen pairs of pole pieces formed as five groups thereof, each group having three pairs of poles angularly spaced from each other by 18°, said groups being angularly spaced from each other by five spacings, four of which are equal to 32.4° and the remaining one of which is equal to 50.4°.
Claim 19
Dependent Claim
82 words
A multiphase rotary stepping motor in accordance with claim 16 wherein said rotor comprises twenty pole pieces angularly and uniformly spaced from each other by 18°; and said stator comprises twenty pairs of pole pieces formed as five groups thereof, each group having four pairs of poles angularly spaced from each other by 18°, said groups being angularly spaced from each other by five spacings, four of which are equal to 14.4° and the remaining one of which is equal to 32.4°.
Claim 20
Dependent Claim
73 words
A multiphase rotary stepping motor in accordance with claim 1, wherein at least one pole face of each of said rotor pole pieces is tapered in a direction to provide a reduced mass at the tips thereof and each corresponding pole face of said stator pole pieces is shaped to provide a uniform gap between said tapered faces of said rotor pole piece and the said corresponding faces of said stator pole pieces.
Claim 21
Dependent Claim
26 words
A multiphase rotary stepping motor in accordance with claim 19, wherein said taper is applied to only one face of each of said rotor pole pieces.
Claim 22
Dependent Claim
26 words
A multiphase rotary stepping motor in accordance with claim 19 wherein said taper is applied to both pole faces of each of said rotor pole pieces.
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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) | 1980-02-01 | 1980-08-02 | 1981-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-01 | 1984-08-02 | 1985-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-01 | 1988-08-02 | 1989-02-01 | $7700.00 | Window Closed / Lapsed |