Patent US4619995A successfully refreshed from Google Patents.
US3579277A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brushless direct current motor
Assignee: Suwa Seikosha KK
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Filing: 1969-04-29
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Granted: 1971-05-18
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Expires: 1989-04-29
Abstract
Abstract In brushless direct current motors having pairs of axially spaced permanent magnets radially arranged about and fixed to a rotor shaft, driving coils disposed in the space between said pairs of permanent magnets and detecting means including detecting coils, and a shield ring having cutaway portions in the path of said detecting coil for the operation of each detecting coil when said cutaway portions are aligned therewith for the activation of the driving coil associated with said detecting coil; the improvement of mounting the driving coils in apertures in an insulated board at an angular interval of about 100* and forming said board with a notch extending from the edge thereof to the center of said driving coils to permit removal of said rotor shaft.
Inventors
- 👤 Issei Imahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:10
CPC Classifications
G; G06; G06K; G06K15/00; G06K15/02; G06K15/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
190 words
In a direct current brushless motor having a rotor shaft, a pair of spaced yokes mounted on said shaft for rotation therewith, a plurality of pairs of permanent magnets radially arranged about said shaft between said yokes, one of each of said pairs of permanent magnets being mounted on each of said yokes with a gap therebetween, a plurality of driving coils disposed in the gap between said pairs of permanent magnets, and a detecting means responsive to the position of said rotor shaft and having at least one detecting coil associated with each driving coil for the activation of said driving coil to rotate said rotor shaft, the improvement which comprises providing three nonoverlapping driving coils having corresponding radial edges thereof circumferentially spaced about said shaft at an angular interval of about 100*, said motor including a base havinG said three driving coils mounted thereon, said base being formed with a notch extending from one edge thereof to the center of said driving coils, said notch being adapted to receive said motor shaft during the operation of said motor and to permit the displacement of said rotor shaft therealong.
Claim 2
Dependent Claim
190 words
In a direct current brushless motor having a rotor shaft, a pair of spaced yokes mounted on said shaft for rotation therewith, a plurality of pairs of permanent magnets radially arranged about said shaft between said yokes, one of each of said pairs of permanent magnets being mounted on each of said yokes with a gap therebetween, a plurality of driving coils disposed in the gap between said pairs of permanent magnets, and a detecting means responsive to the position of said rotor shaft and having at least one detecting coil associated with each driving coil for the activation of said driving coil to rotate said rotor shaft, the improvement which comprises providing three nonoverlapping driving coils having corresponding radial edges thereof circumferentially spaced about said shaft at an angular interval of about 100*, said motor including a base havinG said three driving coils mounted thereon, said base being formed with a notch extending from one edge thereof to the center of said driving coils, said notch being adapted to receive said motor shaft during the operation of said motor and to permit the displacement of said rotor shaft therealong.
Claim 3
Dependent Claim
67 words
A direct current brushless motor as recited in claim 1, wherein said detecting means includes a shield ring on said shaft formed from a conducting material and having cutaway portions in the path of said detecting coils to permit the operation of each of said detecting coils when said cutaway portions are aligned therewith for the activation of the associated driving coil to rotate said rotor shaft.
Claim 4
Dependent Claim
90 words
A brushless direct current motor as recited in claim 2, wherein the poles of each pair of permanent magnets defining the gap therebetween are of opposite polarity to produce a magnetic field in said gap and the poles of adjacent permanent magnets on each of said yokes are of different polarity, said motor being provided with six pairs of permanent magnets circumferentially spaced about said rotor so that each of said pairs of permanent magnets substantially occupies a 60* sector, each of said driving coils substantially occupying a 60* sector.
Claim 5
Dependent Claim
81 words
A direct current brushless motor as recited in claim 2, wherein said shield ring has a plurality of cutaway portions in the path of said detecting coils each permitting the operation of a detecting coil when said cutaway portion is aligned therewith for the activation of the driving coil associated with said detecting coil, said detecting coils being spaced circumferentially about the rotor shaft at 40* intervals, each of said cutaway portions defining a 40* circumferential arc about said rotor shaft.
Claim 6
Dependent Claim
36 words
A direct current brushless motor as recited in claim 4, wherein said motor is provided with three sets of detecting coils, said shield ring being provided with three cutaway regions equally spaced about said rotor shaft.
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) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |