Patent EP0191225A2 successfully refreshed from Google Patents.
EP0191225A2
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EP
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Magnetic bearing device
Assignee: Director-General Of National Aerospace Laboratory
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Filing: 1985-11-01
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Granted: —
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Expires: 2005-11-01
Abstract
Abstract A flywheel assembly has a base (26) and a flywheel (24) rotatable with respect to and in contact-free relation with the base. First and second annular yokes (32, 30) are secured to the base coaxial with the flywheel, and coupled to each other by radially extending control poles (34a to 34d). Control coils (44a to 44d) are wound around the poles. An annular magnet (36) is mounted on the first yoke, coaxial therewith, and a third annular yoke (40) is mounted on the magnet. An outer cylindrical yoke (51) is secured to the flywheel at the outside of the first yoke, and an inner cylindrical yoke (52) is fixed to the flywheel at the inside of the second yoke. The cylindrical yokes are coupled to each other by an annular yoke (53). A magnetic flux from the magnet flows through the magnet, third yoke, outer cylindriCal yoke, first yoke, and the magnet, thereby controlling the axial position of the flywheel. A control flux produced by one of the coils flows through a control magnetic path which passes through one of the poles, first yoke, outer cylindrical yoke, annular yoke, inner cylindrical yoke, second yoke, and said one of the poles, and extends radially with respect to the rotational axis of the flywheel, thereby controlling the radial position of the flywheel.
Inventors
- 👤 Chikara Murakami
- 👤 Atsushi Nakajima
- 👤 Yoshiharu C/O Patent Division Shimamoto
- 👤 Hiroshi C/O Patent Division Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 10:14
CPC Classifications
F; F16; F16C; F16C32/00; F16C32/04; F16C32/0406; F16C32/044; F16C32/0459; F16C32/0461; F16C32/0465; F16C32/0474; F16C32/048; F16C32/0482; F16C2300/00; F16C2300/20; F16C2361/00; F16C2361/55
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
277 words
A magnetic bearing device comprising: a stator; a rotor rotatable with respect to and in contact-free relation with the stator; an annular magnet secured to the stator, coaxial with the rotational axis of the rotor, and magnetized in the axial direction; magnetic path forming means including a stator side yoke secured to the stator and magnetically coupled to the annular magnet, at least three control poles magnetically coupled to the stator side yoke and radially extending with respect to the rotational axis of the rotor in a uniformly separated relationship to one another in the circumferential direction, and a rotor side yoke, secured to the rotor to face the stator side yoke, for forming a first magnetic path for the passage of a magnetic flux from the magnet through the stator side yoke and rotor side yoke to control the axial position of the rotor, and for forming a control magnetic path; control coils, wound around the control poles, for generating a control flux that flows through the control magnetic path, to control the flux flowing through the first magnetic path; detecting means for detecting the relative radial positions of the rotor and stator; and control means for energizing the control coils in accordance with the output of the detecting means to thereby control the radial position of the rotor with respect to the stator; characterized in that said control magnetic path (M3) is a closed loop passing through one of the control poles (34a to 34d), stator side yoke (43) and rotor side yoke, overlapping part of the first magnetic path (Ml) and extending substantially radially with respect to the rotational axis of the rotor (24).
Claim 2
Dependent Claim
277 words
A magnetic bearing device comprising: a stator; a rotor rotatable with respect to and in contact-free relation with the stator; an annular magnet secured to the stator, coaxial with the rotational axis of the rotor, and magnetized in the axial direction; magnetic path forming means including a stator side yoke secured to the stator and magnetically coupled to the annular magnet, at least three control poles magnetically coupled to the stator side yoke and radially extending with respect to the rotational axis of the rotor in a uniformly separated relationship to one another in the circumferential direction, and a rotor side yoke, secured to the rotor to face the stator side yoke, for forming a first magnetic path for the passage of a magnetic flux from the magnet through the stator side yoke and rotor side yoke to control the axial position of the rotor, and for forming a control magnetic path; control coils, wound around the control poles, for generating a control flux that flows through the control magnetic path, to control the flux flowing through the first magnetic path; detecting means for detecting the relative radial positions of the rotor and stator; and control means for energizing the control coils in accordance with the output of the detecting means to thereby control the radial position of the rotor with respect to the stator; characterized in that said control magnetic path (M3) is a closed loop passing through one of the control poles (34a to 34d), stator side yoke (43) and rotor side yoke, overlapping part of the first magnetic path (Ml) and extending substantially radially with respect to the rotational axis of the rotor (24).
Claim 3
Dependent Claim
174 words
The magnetic bearing device according to claim 1, characterized in that said stator side yoke (43) includes a first annular yoke (32) secured to one of the opposite pole surfaces of the magnet (36) and to one end of each of the control poles (34a to 34d), coaxial with the rotational axis of the rotor (24), a second annular yoke (30) secured to the other end of each the control poles and located at the inner side of and coaxially with the first yoke, and a third annular yoke (40) secured to the other one of the pole surfaces of the magnet; and said rotor side yoke (50) has an outer cylindrical portion (51) disposed on the outer side of and facing the magnet, coaxial with the rotational axis of the rotor, an inner cylindrical portion (52) disposed on the inner side of the second yoke, coaxial with the outer cylindrical portion, and an annular portion (53) coupling the outer and inner cylindrical portions together and coaxial with the rotational axis of the rotor.
Claim 4
Dependent Claim
143 words
The magnetic bearing device according to claim 2, characterized in that said outer cylindrical portion (51) has first and second annular projections (54, 55) formed on its inner periphery, the first annular projection facing to and forming a first magnetic gap (G1) with the first yoke (32), and the second annular projection facing to and forming a second magnetic gap (G2) with the third yoke (40); said first magnetic path (Ml) being a closed loop which passes through the magnet (36), third yoke, second magnetic gap, second projection, outer cylindrical portion, first projection, first magnetic gap, first yoke, and back to said magnet; and said control magnetic path (M3) being a closed loop which passes through one control pole, first yoke, first magnetic gap, first projection, outer cylindrical portion, annular portion, inner cylindrical portion, second yoke, and back to said one control pole.
Claim 5
Dependent Claim
63 words
The magnetic bearing device according to claim 3, characterized by further comprising a second annular magnet (38) having one of its opposite pole surfaces secured to the second yoke (30) to control the axial position of the rotor (24); the second magnet being coaxial with the first magnet (36) and magnetized in the same direction as the first magnet along the axial direction.
Claim 6
Dependent Claim
154 words
The magnetic bearing device according to claim 4, characterized in that said stator side yoke (43) includes a fourth annular yoke (42) secured to the other one of the opposite pole surfaces of the second magnet (38) and coaxial with the rotational axis of the rotor (24); said inner cylindrical portion (52) of the rotor side yoke (50) has third and fourth annular projections (56, 57) formed on its outer periphery, the third projection facing to and forming a third magnetic gap (G3) with the second yoke (30), and the fourth projection facing to and forming a fourth magnetic gap (G4) with the fourth yoke; and said magnetic path forming means forms a second magnetic path (M2) through which the flux from the second magnet (38) flows through the second magnet, fourth yoke, fourth magnetic gap, fourth projection, inner cylindrical portion, third projection, third magnetic gap, second yoke and back to said second magnet.
Claim 7
Dependent Claim
155 words
The magnetic bearing device according to claim 2, characterized in that said stator (26) has a cylindrical portion (27), a flange (28) radially extending outward from one end of the cylindrical portion, and an outer end portion (29) extending from the outer periphery of the flange (28), coaxial with the cylindrical portion; said second annular yoke (30) is secured to the outer end portion, coaxial with the cylindrical portion; and said rotor (24) has an inner cylindrical portion (46) located on the outer side of the cylindrical portion in a coaxial and contact-free relation therewith, an outer cylindrical portion (48) coaxial with the inner cylindrical portion of the rotor and covering the outer periphery of the outer cylindrical portion (51) of the rotor side yoke (50), and a flange coupling the outer and inner cylindrical portions of the rotor together and covering the outer surface of the annular portion (53) of the rotor side yoke.
Claim 8
Dependent Claim
45 words
The magnetic bearing device according to claim 6, characterized in that said detecting means includes a pair of sensors (62, 63) secured to the cylindrical portion (27) of the stator (26) to face the outer periphery of the inner cylindrical portion (46) of said rotor.
Claim 9
Dependent Claim
45 words
The magnetic bearing device according to claim 7, characterized in that said magnetic path forming means includes four control poles (34a to 34d) uniformly spaced apart in the circumferential direction; said sensors (62, 63) being located on the center lines of two adjacent control poles.
Claim 10
Dependent Claim
67 words
The magnetic bearing device according to claim 6, characterized by further comprising a motor (60) for rotating the rotor (24), the motor including an annular stator element (58) secured to the flange (28) of the stator (26) coaxial with the cylindrical portion (27), and an annular rotor element (59) secured to the flange (47) of the rotor coaxial with the cylindrical and co-operating with the stator element.
Claim 11
Dependent Claim
40 words
The magnetic bearing device according to claim 6, characterized by further comprising a mechanical bearing (66, 67) secured to the outer periphery of the cylindrical portion (27) of the stator to support the rotor (24) only in cases of emergency.
Claim 12
Dependent Claim
175 words
The magnetic bearing device according to claim 1, characterized in that said stator side yoke (43) includes an outer cylindrical portion (74) disposed on the outer side of, and coaxially with, the magnet, (36) and coupled to one end of each of the control poles (34a to 34d); an inner cylindrical portion (75) disposed on the inner side of, and coaxially with, the outer cylindrical portion, and coupled to the other end of each control pole; a first annular yoke (76) secured to the inner peripheral surface of the outer cylindrical portion and also to one of the opposite pole surfaces of the magnet, coaxial with the magnet; a second annular yoke (77) secured to the outer peripheral surface of the inner cylindrical portion, coaxial with the first yoke; and a third annular yoke (78) secured to the other one of the opposite pole surfaces of the magnet, coaxial with the magnet; and said rotor side yoke includes an annular yoke (84) disposed between and facing the first and second yokes, coaxial with the magnet.
Claim 13
Dependent Claim
144 words
The magnetic bearing device according to claim 1, characterized in that said rotor side annular yoke (84) has first and second annular projections (86, 87) formed on its outer periphery, the first projection facing to and forming a first magnetic gap (G1) with the first yoke (76), the second projection facing to and forming a second magnetic gap (G2) with the third yoke (78); said first magnetic path (M2) is a closed loop which passes through the magnet (36), first yoke, first magnetic gap, first projection, rotor side annular yoke, second projection second magnetic gap, third yoke, and back to said magnet; and said control magnetic path is a closed loop which passes through the one control pole, outer cylindrical portion (74), first yoke, first magnetic gap rotor side annular yoke (77), second yoke, inner cylindrical portion (75), and back to said control pole.
Claim 14
Dependent Claim
63 words
The magnetic bearing device according to claim 12, characterized by further comprising a second annular magnet (38) having one of its opposite pole surfaces secured to the second yoke (77) to control the axial position of the rotor (24); the second magnet being coaxial with the first magnet (36) and magnetized in the same direction as the first magnet along the axial direction.
Claim 15
Dependent Claim
148 words
The magnetic bearing device according to claim 3, characterized in that said stator side yoke (43) has a fourth annular yoke (79) secured to the other one of the opposite pole surfaces of the second magnet (38) and coaxial with the rotational axis of the rotor (24); said rotor side annular yoke (84) has third and fourth annular projections (88, 89) formed on its inner periphery, the third projection facing to and forming a third magnetic gap (G3) with the second yoke (77), the fourth projection facing to and forming a fourth magnetic gap (G4) with the fourth yoke; and said magnetic path forming means forms a second magnetic path through which the flux from the second magnet flows through the second magnet, second yoke, third magnetic gap, third projection, rotor side annular yoke (84), fourth projection fourth magnetic gap fourth yoke, and back to said second magnet.
References Cited (Backward Citations)
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