Patent US3751696A successfully refreshed from Google Patents.
US3751696A
Expired / Lapsed
US
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Tooth arrangement for a stepping motor
Assignee: COMPUTER DEVICES
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Filing: 1971-11-22
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Granted: 1973-08-07
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Expires: 1991-11-22
Abstract
Abstract A stepping motor includes a stator assembly and a rotor assembly having teeth projecting toward each other. The rotor assembly includes a plurality of permanent magnets spaced-apart along the rotational axis with repelling poles of adjacent magnets facing each other. The teeth on the rotor project from a plurality of axially spaced-apart cylindrical members that cooperate with the magnets to form magnetic poles of the rotor with an interior member cooperating with near ends of adjacent magnets to form a single magnetic pole. In operation, magnetic flux lines between the stator and rotor assemblies split to form parallel circuits having a common path through the interior member. The teeth are arranged in an alternating offset configuration having three axially extending sections corresponding to the three cylindrical rotor members. For each section there are a plurality of teeth on the stator that attract teeth on the rotor member and a separate plurality of teeth on the stator that repel teeth on the rotor member. Each tooth of the plurality of attracted teeth on the rotor member aligns itself with a tooth on the stator. On the other hand, each tooth of the plurality of repelling teeth on the stator projects toward the middle of the space between adjacent teeth on the rotor and repel them equally.
Inventors
- 👤 A Morreale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:07
CPC Classifications
H; H02; H02K; H02K37/00; H02K37/10; H02K37/12; H02K37/14; H02K37/18
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
226 words
In a stepping motor having a stator assembly and a rotor assembly positioned for rotation within the stator assembly, the stator assembly having teeth projecting toward teeth on the rotor assembly, the improvement comprising magnetic means in the rotor assembly including two permanent magnets providing magnetic poles spaced apart along the rotational axis with adjacent poles having the same magnetic polarity, a single magnetic pole piece between adjacent magnets, and a pole piece at either end of the rotor assembly; each pair of adjacent teeth on one of the assemblies defining a straight continuous notch extending parallel to the rotational axis; and the teeth on the other assembly having a series of axially extending portions, one portion for each magnetic pole piece of the magnetic means, the teeth of each portion being angularly offset from the adjacent portion by onehalf of the pitch so that for each tooth a straight line is defined by each portion thereof which lies in the middle of the space between adjacent teeth on an axially adjacent portion of the assembly; and each magnetic pole piece between two magnets of the rotor being in both a magnetic circuit that includes the permanent magnet of the rotor axially adjacent thereto on one side and a magnetic circuit that includes the permanent magnet of the rotor axially adjacent thereto on the opposite side.
Claim 2
Dependent Claim
226 words
In a stepping motor having a stator assembly and a rotor assembly positioned for rotation within the stator assembly, the stator assembly having teeth projecting toward teeth on the rotor assembly, the improvement comprising magnetic means in the rotor assembly including two permanent magnets providing magnetic poles spaced apart along the rotational axis with adjacent poles having the same magnetic polarity, a single magnetic pole piece between adjacent magnets, and a pole piece at either end of the rotor assembly; each pair of adjacent teeth on one of the assemblies defining a straight continuous notch extending parallel to the rotational axis; and the teeth on the other assembly having a series of axially extending portions, one portion for each magnetic pole piece of the magnetic means, the teeth of each portion being angularly offset from the adjacent portion by onehalf of the pitch so that for each tooth a straight line is defined by each portion thereof which lies in the middle of the space between adjacent teeth on an axially adjacent portion of the assembly; and each magnetic pole piece between two magnets of the rotor being in both a magnetic circuit that includes the permanent magnet of the rotor axially adjacent thereto on one side and a magnetic circuit that includes the permanent magnet of the rotor axially adjacent thereto on the opposite side.
Claim 3
Dependent Claim
221 words
A stepping motor comprising a stator assembly including a core of magnetic material and having a plurality of salient poles, each pole terminating in an arcuate inner surface with the arcuate surfaces defining a cylindrical opening; and a cylindrical rotor assembly rotatably positioned in the opening, the rotor assembly including magnetic means having axially spaced-apart consequent magnetic poles, and two end and one intermediate cylindrical pole members each having around the periphery thereof substantially equal spaced-apart teeth extending parallel to the rotational axis of the member, the end members cooperating with the magnetic means to form like magnetic poles and the intermediate member cooperating with the magnetic means to form the opposite magnetic pole, the arcuate surfaces of each of the salient poles of the stator assembly having substantially equally spaced-apart teeth projecting toward the teeth in the rotor assembly, the teeth on one of said stator and rotor assemblies being axially aligned throughout its full length, the teeth on a first intermediate portion of the other assembly being axially aligned through the length of the intermediate portion, the teeth on second and third portions that extend axially from opposite ends of the intermediate portion being axially aligned with each other and offset from the teeth on the intermediate portion by an amount equal to one-half of the spacing between teeth.
Claim 4
Dependent Claim
221 words
A stepping motor comprising a stator assembly including a core of magnetic material and having a plurality of salient poles, each pole terminating in an arcuate inner surface with the arcuate surfaces defining a cylindrical opening; and a cylindrical rotor assembly rotatably positioned in the opening, the rotor assembly including magnetic means having axially spaced-apart consequent magnetic poles, and two end and one intermediate cylindrical pole members each having around the periphery thereof substantially equal spaced-apart teeth extending parallel to the rotational axis of the member, the end members cooperating with the magnetic means to form like magnetic poles and the intermediate member cooperating with the magnetic means to form the opposite magnetic pole, the arcuate surfaces of each of the salient poles of the stator assembly having substantially equally spaced-apart teeth projecting toward the teeth in the rotor assembly, the teeth on one of said stator and rotor assemblies being axially aligned throughout its full length, the teeth on a first intermediate portion of the other assembly being axially aligned through the length of the intermediate portion, the teeth on second and third portions that extend axially from opposite ends of the intermediate portion being axially aligned with each other and offset from the teeth on the intermediate portion by an amount equal to one-half of the spacing between teeth.
Claim 5
Dependent Claim
50 words
A stepping motor according to claim 2 wherein the magnetic means includes two permanent magnets spaced-apart along the rotational axis and having like magnetic poles facing each other, the adjacent ends of the two magnets cooperatiNg with the second cylindrical member to form a single one of the magnetic poles.
Claim 6
Dependent Claim
57 words
A stepping motor according to claim 3, the teeth on the rotor assembly being axially aligned throughout its full length, the stator assembly salient poles and the teeth projecting therefrom comprising two end stacks and an intermediate stack of laminations, the laminations in each stack being secured face-to-face with the teeth in the stack being axially aligned.
Claim 7
Dependent Claim
23 words
A stepping motor according to claim 4 wherein the intermediate stack axially extends between the approximate axial midpoints of the two permanent magnets.
Claim 8
Dependent Claim
120 words
A stepping motor according to claim 2 wherein the salient poles and the teeth projecting therefrom comprise two end stacks and an intermediate stack of identically shaped laminations wherein the radial centerline of a tooth on each lamination is offset from the radial centerline of a pole portion by an amount equal to one-fourth of the spacing between adjacent teeth, and means securing the stacks with alternate offsets such that the centerlines of each pole portion of all laminations are aligned and the laminations in the intermediate stack has its teeth offset in one direction relative to the centerline of the pole portion and the laminations in the two end stacks each have their teeth offset in the other direction.
Claim 9
Dependent Claim
204 words
A stepping motor comprising a stator including a single core of magnetic material and having a plurality of poles forming a cylindrical opening, a rotor positioned for rotation within the cylinder opening of the stator, the rotor including at least two permanent magnet means magnetically polarized in a direction parallel to the axis of rotation of the rotor with the direction of flux being opposite in adjacent magnet means, each of the magnet means including pole members at either end, one of the pole members being common to adjacent magnet means, each of the pole members having a cylindrical surface concentric to and closely spaced from the cylinder opening of the stator, the cylindrical surface of the pole members and the poles of the stator having radially projecting teeth extending parallel to the axis of rotation of the rotor, the teeth being angularly positioned such that for a given pole of the stator when the teeth of the stator are directly aligned with the teeth of the common pole member associated with a pair of adjacent magnet means of the rotor, the teeth of the two outer pole members of the adjacent magnetic means are offset relative to the teeth on the stator pole.
Claim 10
Dependent Claim
204 words
A stepping motor comprising a stator including a single core of magnetic material and having a plurality of poles forming a cylindrical opening, a rotor positioned for rotation within the cylinder opening of the stator, the rotor including at least two permanent magnet means magnetically polarized in a direction parallel to the axis of rotation of the rotor with the direction of flux being opposite in adjacent magnet means, each of the magnet means including pole members at either end, one of the pole members being common to adjacent magnet means, each of the pole members having a cylindrical surface concentric to and closely spaced from the cylinder opening of the stator, the cylindrical surface of the pole members and the poles of the stator having radially projecting teeth extending parallel to the axis of rotation of the rotor, the teeth being angularly positioned such that for a given pole of the stator when the teeth of the stator are directly aligned with the teeth of the common pole member associated with a pair of adjacent magnet means of the rotor, the teeth of the two outer pole members of the adjacent magnetic means are offset relative to the teeth on the stator pole.
Claim 11
Dependent Claim
221 words
A stator core for a stepping motor comprising two end stacks and at least one intermediate stack of laminations, the end stacks being in direct contact with the intermediate stack to form a unitary magnetic core structure, each stack comprising a plurality of flat cylindrical laminations of magnetic material, the two end stacks extending axially a substantially equal, first distance and each intermediate stack extending axially approximately twice the first distance, each lamination having an outer ring portion and a plurality of equally spaced pole portions that project radially inwardly, the inner edge of the pole portions forming arcs of a common circle concentric with the ring portion, the inner edge having a plurality of equally spaced teeth that project radially inwardly, the radial centerline of one of the teeth being offset from the radial centerline of the pole portion by an amount that is one-fourth of the spacing between adjacent teeth, the laminations in each stack being secured face-to-face with the teeth in the stack being axially aligned, and means securing the stacks with alternate offsets such that the centerlines of each of the pole portions of all the laminations are aligned and the laminations in each two adjacent stacks have their teeth offset to the left and to the right respectively relative to the centerline of the pole portions.
Claim 12
Dependent Claim
221 words
A stator core for a stepping motor comprising two end stacks and at least one intermediate stack of laminations, the end stacks being in direct contact with the intermediate stack to form a unitary magnetic core structure, each stack comprising a plurality of flat cylindrical laminations of magnetic material, the two end stacks extending axially a substantially equal, first distance and each intermediate stack extending axially approximately twice the first distance, each lamination having an outer ring portion and a plurality of equally spaced pole portions that project radially inwardly, the inner edge of the pole portions forming arcs of a common circle concentric with the ring portion, the inner edge having a plurality of equally spaced teeth that project radially inwardly, the radial centerline of one of the teeth being offset from the radial centerline of the pole portion by an amount that is one-fourth of the spacing between adjacent teeth, the laminations in each stack being secured face-to-face with the teeth in the stack being axially aligned, and means securing the stacks with alternate offsets such that the centerlines of each of the pole portions of all the laminations are aligned and the laminations in each two adjacent stacks have their teeth offset to the left and to the right respectively relative to the centerline of the pole portions.
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) | 1976-08-06 | 1977-02-05 | 1977-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-06 | 1981-02-05 | 1981-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-06 | 1985-02-05 | 1985-08-07 | $7700.00 | Window Closed / Lapsed |