Patent US5148090A successfully refreshed from Google Patents.
US5148090A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable reluctance type ac servo motor
Assignee: Fanuc Corp
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Filing: 1989-09-28
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Granted: 1992-09-15
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Expires: 2009-09-28
Abstract
Abstract This invention determines the configurations of a rotor (10) and a stator (12) and conductance periods and conductance phases of the conductance currents to obtain a smooth rotation of a variable reluctance motor as an AC servo motor. When the number of phases of a motor is m, the number of salient poles (R j ) of a rotor (10) is an integer n, and the number of salient poles (S k ) of a stator (12 ) is r·m, n is a whole multiple of r, and where the configuration of the stator salient pole (S k ) is rectangular and the configuration of the rotor salient pole (R j ) is sinusoidal, AC sine wave currents shifted by 2nπ/(r·m) each and having two times as large a period as that of a magnetic permeance fluctuation caused by a rotation of the rotor (10), are conducted to the phases of the motor.
Inventors
- 👤 Hideaki Oku
- 👤 Takeshi Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:53
CPC Classifications
H; H02; H02K; H02K19/00; H02K19/02; H02K19/10; H02K19/103
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
197 words
A variable reluctance type AC servo motor comprising: a stator having a plurality of salient poles, each said stator salient pole having a substantially rectangular surface area; a rotor having a plurality of salient poles opposing said stator salient poles, each said rotor salient pole having a surface area opposing said stator salient poles shaped such that, upon rotation of said rotor, the surface area of each rotor salient pole opposing a stator salient pole varies continuously in a sinusoidal manner; and means for applying AC singe wave excitation currents to windings of said stator poles; wherein the number of m of phases of excitation currents is at least 3, the number of poles of said rotor is an integer n and the number of poles of said stator is r·m, n being a whole multiple of the number r but not a whole multiple of r·m; and wherein the m phase currents have a period Hz equal to twice a period of fluctuation of magnetic permeance caused by rotation of the rotor, and a conductance phase between adjoining stator poles is shifted 2n π/(r·m) at each phase of magnetic permeance fluctuation, whereby torque ripple is eliminated.
Claim 2
Dependent Claim
197 words
A variable reluctance type AC servo motor comprising: a stator having a plurality of salient poles, each said stator salient pole having a substantially rectangular surface area; a rotor having a plurality of salient poles opposing said stator salient poles, each said rotor salient pole having a surface area opposing said stator salient poles shaped such that, upon rotation of said rotor, the surface area of each rotor salient pole opposing a stator salient pole varies continuously in a sinusoidal manner; and means for applying AC singe wave excitation currents to windings of said stator poles; wherein the number of m of phases of excitation currents is at least 3, the number of poles of said rotor is an integer n and the number of poles of said stator is r·m, n being a whole multiple of the number r but not a whole multiple of r·m; and wherein the m phase currents have a period Hz equal to twice a period of fluctuation of magnetic permeance caused by rotation of the rotor, and a conductance phase between adjoining stator poles is shifted 2n π/(r·m) at each phase of magnetic permeance fluctuation, whereby torque ripple is eliminated.
Claim 3
Dependent Claim
73 words
A variable reluctance type AC servo motor according to claim 1, wherein the number n of said rotor salient poles is equal to at least the number m of phases, sinusoidal variation of surface area of a rotor salient pole opposing the stator salient pole has a pitch dimension RP in a circumferential direction of said rotor, and each stator salient pole has a dimension in a circumferential direction equal to RP 2.
Claim 4
Dependent Claim
91 words
A variable reluctance type AC servo motor according to claim 1, wherein said rotor is constructed of a plurality of superposed identical plate members, each of which plate members is formed with a number n of angularly equi-spaced projecting portions of equal width in a circumferential direction, and wherein adjacent said plate members are skewed with respect to each other in a longitudinal direction said rotor such that said projecting portions form said rotor salient poles wherein a surface area opposing each stator salient pole varies sinusoidally as said rotor rotates.
Claim 5
Dependent Claim
90 words
A variable reluctance type AC servo motor according to claim 2, wherein said rotor is constructed of a plurality of superposed identical plate members, each of which plate members is formed with a number n of angularly equi-spaced projecting portions of equal width in the circumferential direction, and wherein adjacent plate members are skewed with respect to each other in a longitudinal direction of said rotor such that said projecting portions form said rotor salient poles wherein a surface area opposing each stator salient varies sinuosidally as said rotor rotates.
Claim 6
Dependent Claim
25 words
A variable reluctance type AC servo motor according to claim 3, wherein said motor includes a plurality of said rotors arranged longitudinally of said rotor.
Claim 7
Dependent Claim
25 words
A variable reluctance type AC servo motor according to claim 4, wherein said motor includes a plurality of said rotors arranged longitudinally of said motor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1995-09-15 | 1996-03-16 | 1996-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-15 | 2000-03-16 | 2000-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-15 | 2004-03-16 | 2004-09-15 | $7700.00 | Window Closed / Lapsed |