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US4516048A Expired / Lapsed US ⏱️ 0.0 years remaining

Stator with nonuniformly spaced teeth for rotating electromagnetic device

Assignee: Dana Inc
•
Filing: 1983-09-29
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Granted: 1985-05-07
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Expires: 2003-09-29
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Abstract

Abstract An electromagnetic device of the type having a rotor and a stator with magnetically coacting peripheries, with the stator having toothed pole structures, has the stator pole teeth set at nonuniform spacing to improve the operating characteristics of the device. When the device is a stepping motor, improved step accuracy is attained through reduction of residual (or detent) torque. Reduction of airborne noise is reduced in all motor types.

Inventors

  • 👤 Robert N. Brigham

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-30 10:04
CPC Classifications
H; H02; H02K; H02K21/00; H02K21/12; H02K21/14; H02K21/20; H02K37/00; H02K37/10; H02K37/12; H02K37/14; H02K37/18

Claims Analysis

Total Claims: 22
Claim 1
Independent Claim 131 words
In an electromagnetic device of the type in which there is a rotor and a stator having toothed, electromagnetically coacting peripheries, the stator having poles and at least one winding comprising coils wound upon the poles to form magnetic poles upon energization of the winding, the improvement comprising having the stator teeth set at nonuniform spacing so that the vector sum of the values determined by the following relationship for each pole is zero: ##EQU2## n r =number of rotor teeth, N=number of stator teeth on the pole, a 1 =0, a n =center-to-center distance from the tooth at one edge of the pole to the tooth designated by a numeral subscript, the tooth at the other edge of the pole being designated as N, in mechanical degrees, and p=an integer.
Claim 2
Dependent Claim 131 words
In an electromagnetic device of the type in which there is a rotor and a stator having toothed, electromagnetically coacting peripheries, the stator having poles and at least one winding comprising coils wound upon the poles to form magnetic poles upon energization of the winding, the improvement comprising having the stator teeth set at nonuniform spacing so that the vector sum of the values determined by the following relationship for each pole is zero: ##EQU2## n r =number of rotor teeth, N=number of stator teeth on the pole, a 1 =0, a n =center-to-center distance from the tooth at one edge of the pole to the tooth designated by a numeral subscript, the tooth at the other edge of the pole being designated as N, in mechanical degrees, and p=an integer.
Claim 3
Dependent Claim 148 words
In an electromagnetic device of the type in which there is a rotor and a stator having electromagnetically coacting peripheries, the rotor being toothless and having magnetic poles uniformly disposed radially on the surface thereof, the stator having toothed poles and at least one winding comprising coils wound upon the poles to form magnetic poles upon energization of the winding, the improvement comprising having the stator teeth set at nonuniform spacing so that the vector sum of the values determined by the following relationship for each stator pole is zero. ##EQU3## n r =number of rotor magnetic poles, N=number of teeth on the stator pole, a 1 =0, a n =center-to-center distance from the tooth at one edge of the pole to the tooth designated by a numeral subscript, the tooth at the other edge of the pole being designated as N, in mechanical degrees, and p=an integer.
Claim 4
Dependent Claim 148 words
In an electromagnetic device of the type in which there is a rotor and a stator having electromagnetically coacting peripheries, the rotor being toothless and having magnetic poles uniformly disposed radially on the surface thereof, the stator having toothed poles and at least one winding comprising coils wound upon the poles to form magnetic poles upon energization of the winding, the improvement comprising having the stator teeth set at nonuniform spacing so that the vector sum of the values determined by the following relationship for each stator pole is zero. ##EQU3## n r =number of rotor magnetic poles, N=number of teeth on the stator pole, a 1 =0, a n =center-to-center distance from the tooth at one edge of the pole to the tooth designated by a numeral subscript, the tooth at the other edge of the pole being designated as N, in mechanical degrees, and p=an integer.
Claim 5
Dependent Claim 22 words
The improvement, as defined in claim 1, further defined, wherein the value determined by the relationship for each individual pole is zero.
Claim 6
Dependent Claim 22 words
The improvement, as defined in claim 2, further defined, wherein the value determined by the relationship for each individual pole is zero.
Claim 7
Dependent Claim 16 words
The improvement, as defined in claim 1, further defined, wherein the electromagnetic device is a generator.
Claim 8
Dependent Claim 16 words
The improvement, as defined in claim 2, further defined, wherein the electromagnetic device is a generator.
Claim 9
Dependent Claim 16 words
The improvement, as defined in claim 1, further defined, wherein the electromagnetic device is a motor.
Claim 10
Dependent Claim 16 words
The improvement, as defined in claim 2, further defined, wherein the electromagnetic device is a motor.
Claim 11
Dependent Claim 17 words
The improvement, as defined in claim 1, further defined, wherein the electromagnetic device is a stepping motor.
Claim 12
Dependent Claim 17 words
The improvement, as defined in claim 2, further defined, wherein the electromagnetic device is a stepping motor.
Claim 13
Dependent Claim 120 words
In an electrical stepping motor of the type having a toothed rotor having uniform tooth spacing and a stator having toothed poles energized by at least one winding comprising coils wound upon the poles, the improvement comprising having the pole teeth set at nonuniform spacing so that the vector sum of the values determined by the following relationship for each pole is zero: ##EQU4## n r =number of rotor teeth, N=number of stator teeth on the pole, a 1 =0, a n =center-to-center distance from the tooth at one edge of the pole to the tooth designated by a numeral subscript, the tooth at the other edge of the pole being designated as N, in mechanical degrees, and p=an integer.
Claim 14
Dependent Claim 120 words
In an electrical stepping motor of the type having a toothed rotor having uniform tooth spacing and a stator having toothed poles energized by at least one winding comprising coils wound upon the poles, the improvement comprising having the pole teeth set at nonuniform spacing so that the vector sum of the values determined by the following relationship for each pole is zero: ##EQU4## n r =number of rotor teeth, N=number of stator teeth on the pole, a 1 =0, a n =center-to-center distance from the tooth at one edge of the pole to the tooth designated by a numeral subscript, the tooth at the other edge of the pole being designated as N, in mechanical degrees, and p=an integer.
Claim 15
Dependent Claim 131 words
In an electrical stepping motor of the type having a toothed rotor having uniform tooth spacing and a stator having toothed poles energized by at least one winding comprising coils wound upon the poles, the improvement comprising having the pole teeth set at nonuniform spacing so that the vector sum of the values determined by the following relationship for each pole is zero: ##EQU5## n r =number of rotor teeth, N=number of stator teeth on the pole, a 1 =0, a n =center-to-center distance from the tooth at one edge of the pole to the tooth designated by a numeral subscript, the tooth at the other edge of the pole being designated as N, in mechanical degrees, and h=the number of a harmonic of the fundamental torque-angle characteristic of the motor.
Claim 16
Dependent Claim 131 words
In an electrical stepping motor of the type having a toothed rotor having uniform tooth spacing and a stator having toothed poles energized by at least one winding comprising coils wound upon the poles, the improvement comprising having the pole teeth set at nonuniform spacing so that the vector sum of the values determined by the following relationship for each pole is zero: ##EQU5## n r =number of rotor teeth, N=number of stator teeth on the pole, a 1 =0, a n =center-to-center distance from the tooth at one edge of the pole to the tooth designated by a numeral subscript, the tooth at the other edge of the pole being designated as N, in mechanical degrees, and h=the number of a harmonic of the fundamental torque-angle characteristic of the motor.
Claim 17
Dependent Claim 137 words
In an electrical stepping motor of the type having a toothless rotor having magnetic poles uniformly disposed radially on the surface thereof and a stator having toothed poles energized by at least one winding comprising coils wound upon the poles, the improvement comprising having the pole teeth set at nonuniform spacing so that the vector sum of the values determined by the following relationship for each stator pole is zero: ##EQU6## n r =number of rotor magnetic poles, N=number of teeth on the stator pole, a 1 =0, a n =center-to-center distance from the tooth at one edge of the stator pole to the tooth designated by a numeral subscript, the tooth at the other edge of the stator pole being designated as N, in mechanical degrees, and p=the number of magnetic poles included in each winding.
Claim 18
Dependent Claim 137 words
In an electrical stepping motor of the type having a toothless rotor having magnetic poles uniformly disposed radially on the surface thereof and a stator having toothed poles energized by at least one winding comprising coils wound upon the poles, the improvement comprising having the pole teeth set at nonuniform spacing so that the vector sum of the values determined by the following relationship for each stator pole is zero: ##EQU6## n r =number of rotor magnetic poles, N=number of teeth on the stator pole, a 1 =0, a n =center-to-center distance from the tooth at one edge of the stator pole to the tooth designated by a numeral subscript, the tooth at the other edge of the stator pole being designated as N, in mechanical degrees, and p=the number of magnetic poles included in each winding.
Claim 19
Dependent Claim 141 words
In an electrical stepping motor of the type having a toothless rotor having magnetic poles uniformly disposed radially on the surface thereof and a stator having toothed poles energized by at least one winding comprising coils wound upon the poles, the improvement comprising having the pole teeth set at nonuniform spacing so that the vector sum of the values determined by the following relationship for each stator pole is zero: ##EQU7## n r =number of rotor magnetic poles, N=number of teeth on the stator pole, a 1 =0, a n =center-to-center distance from the tooth at one edge of the stator pole to the tooth designated by a numeral subscript, the tooth at the other edge of the stator pole being designated as N, in mechanical degrees, and h=the number of a harmonic of the fundamental torque-angle characteristic of the motor.
Claim 20
Dependent Claim 141 words
In an electrical stepping motor of the type having a toothless rotor having magnetic poles uniformly disposed radially on the surface thereof and a stator having toothed poles energized by at least one winding comprising coils wound upon the poles, the improvement comprising having the pole teeth set at nonuniform spacing so that the vector sum of the values determined by the following relationship for each stator pole is zero: ##EQU7## n r =number of rotor magnetic poles, N=number of teeth on the stator pole, a 1 =0, a n =center-to-center distance from the tooth at one edge of the stator pole to the tooth designated by a numeral subscript, the tooth at the other edge of the stator pole being designated as N, in mechanical degrees, and h=the number of a harmonic of the fundamental torque-angle characteristic of the motor.
Claim 21
Dependent Claim 22 words
The improvement, as defined in claim 14, further defined, wherein the value determined by the relationship for each individual pole is zero.
Claim 22
Dependent Claim 22 words
The improvement, as defined in claim 14, further defined, wherein the value determined by the relationship for each individual pole is zero.

References Cited (Backward Citations)

US3482156A Cited
US3866104A Cited
US4081703A Cited
US4112319A Cited
US4385247A Cited
US4385250A Cited
US4423343A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1988-05-06 1988-11-05 1989-05-07 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1992-05-06 1992-11-05 1993-05-07 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1996-05-06 1996-11-05 1997-05-07 $7700.00 Window Closed / Lapsed

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