EP0128508A2
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EP
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Method and apparatus for producing anisotropic magnets
Assignee: Proterial Ltd
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Filing: 1984-06-05
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Granted: —
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Expires: 2004-06-05
Abstract
Abstract A method of producing an anisotropic magnet from a composition essentially consisting of magnetic powder and a binder in the presence of an anisotropically oriented magnetic field used a mold (1) which comprises a mold body (2), a cavity (4) for molding the composition, a plurality of first magnet means (6a ... 6d) for providing magnetic fluxes constituting the magnetic field in the cavity (4), yokes (7a... 7d) each provided between the cavity (4) and the first magnet means (6a ... 6d), and second magnet means (8a ... 8d) provided on both sides of the yokes (7a ... 7d) for preventing leakage of the magnetic fluxes. The first and second magnet means (6a ... 6d, 8a... 8d) are made of permanent magnet such as rare earth cobalt magnet. The mold (1) may be provided at both ends with third magnet means for preventing axial leakage of the magnetic flux. Two or more molds may be combined in a single molding apparatus while sharing the first magnet means. This mold (1) is suitable for the injection, extrusion or insert molding of bonded magnet rolls, motor rotors, etc.
Inventors
- 👤 Shigeho Tanigawa
- 👤 Shuichi Shiina
- 👤 Kimio Uchida
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 11:21
CPC Classifications
H; H01; H01F; H01F13/00; H01F13/003; B; B29; B29C; B29C45/00; B29C45/0013; H01F41/00; H01F41/02; H01F41/0253; H01F41/0273; H01F41/028; H01F7/00; H01F7/02; H01F7/0231; H01F7/0252; H01F7/0268; Y; Y10; Y10S; Y10S425/00; Y10S425/033
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
109 words
A method of producing an anisotropic magnet comprising molding a composition essentially consisting of magnetic powder and a binder in a mold (1) in the presence of an anisotropically oriented magnetic field, said mold (1) comprising a plurality of first magnet means (6a...6d) arranged circumferentially around a molding cavity (4) of said mold (1) for providing magnetic fluxes constituting said magnetic field, yokes (7a...7d) each provided between said cavity (4) and each of said first magnet means (6a...6d) for directing said each magnetic flux into said cavity (4), and second magnet means (8a...8d) provided on both sides of said yokes (7a...7d) for preventing the leakage of said magnetic fluxes.
Claim 2
Independent Claim
109 words
A method of producing an anisotropic magnet comprising molding a composition essentially consisting of magnetic powder and a binder in a mold (1) in the presence of an anisotropically oriented magnetic field, said mold (1) comprising a plurality of first magnet means (6a...6d) arranged circumferentially around a molding cavity (4) of said mold (1) for providing magnetic fluxes constituting said magnetic field, yokes (7a...7d) each provided between said cavity (4) and each of said first magnet means (6a...6d) for directing said each magnetic flux into said cavity (4), and second magnet means (8a...8d) provided on both sides of said yokes (7a...7d) for preventing the leakage of said magnetic fluxes.
Claim 3
Dependent Claim
22 words
The method of claim 1, wherein said magnetic powder is ferrite powder having an average particle size of 0.9 - 2.5 µm.
Claim 4
Dependent Claim
24 words
The method of claim 2, wherein said ferrite powder is selected from the group consisting of Sr-ferrite powder, Ba-ferrite powder and a mixture thereof.
Claim 5
Dependent Claim
103 words
A mold for producing an anisotropic magnet comprising: a mold body (2); a cavity (4) for molding a composition essentially consisting of magnetic powder and a binder in the presence of an anisotropically oriented magnetic field; a plurality of first magnet means (6a...6d) arranged around said molding cavity (4) for providing magnetic fluxes constituting said magnetic field; yokes (7a...7d) each provided between said cavity (4) and each of said first magnet means (6a...6d) for directing said magnetic flux into said cavity (4); and second magnet means (8a...8d) provided on both sides of said yokes (7a...7d) for preventing the leakage of said magnetic fluxes.
Claim 6
Dependent Claim
103 words
A mold for producing an anisotropic magnet comprising: a mold body (2); a cavity (4) for molding a composition essentially consisting of magnetic powder and a binder in the presence of an anisotropically oriented magnetic field; a plurality of first magnet means (6a...6d) arranged around said molding cavity (4) for providing magnetic fluxes constituting said magnetic field; yokes (7a...7d) each provided between said cavity (4) and each of said first magnet means (6a...6d) for directing said magnetic flux into said cavity (4); and second magnet means (8a...8d) provided on both sides of said yokes (7a...7d) for preventing the leakage of said magnetic fluxes.
Claim 7
Dependent Claim
58 words
The mold of claim 4, wherein the number of said first magnet means (6a...6c) is odd, and a non-magnetic spacer (9) is provided between the two second magnet means (8b, 8c) with the same magnetic poles facing each other, thereby reducing the magnetic flux at the cavity (4) surface adjacent to said non-magnetic spacer (9) to substantially zero.
Claim 8
Dependent Claim
66 words
The mold of claim 4 or 5, further comprising third magnetic means (12a...12d) arranged at the ends of said yokes (7a...7d), in such a manner that the magnetic pole of each third magnet means (12a...12d) facing each of said yokes (7a...7d) is the same as that of said first magnet means (6a...6d) contacting with said each yoke X7a...7d), thereby preventing the magnetic fluxes from leaking axially.
Claim 9
Dependent Claim
44 words
The mold of any of claims 4 to 6, wherein each of said second magnet means (8a...8d) is arranged such that each magnetic pole thereof faces the yoke (7a...7d) which is in contact with the same magnetic pole of said first magnet means (6a...6d).
Claim 10
Dependent Claim
25 words
The mold of any of claims 4 to 7, wherein said first, second and third magnet means (6a...6d, 8a...8d, 12a...12d) are made of permanent magnet.
Claim 11
Dependent Claim
14 words
The method of claim 8, wherein said permanent magnet is rare earth cobalt magnet.
Claim 12
Dependent Claim
18 words
The mold of any of claims 4 to 9, wherein said yokes (7a...7d) are made of soft-magnetic material.
Claim 13
Dependent Claim
30 words
The mold of any of claims 4 to 10, wherein said mold body (2) is made of soft-magnetic material, so that it serves as means for conducting the magnetic flux.
Claim 14
Dependent Claim
20 words
The mold of any of claims 4 to 11, wherein said cavity (4) is defined by a non-magnetic sleeve (3).
Claim 15
Dependent Claim
22 words
The mold of any of claims 4 to 12, wherein said molding cavity (4) is cylindrical and comprises a central core (5).
Claim 16
Dependent Claim
33 words
The mold of any of claims 4 to 12, wherein said molding cavity (4) .is cylindrical and receives a shaft (13) which is adapted to be fixed to the resulting magnet molding (14).
Claim 17
Dependent Claim
31 words
The mold of any of claims 4 to 14, wherein the length-diameter ratio of said cavity (4) is more than 5, whereby it is suitable for producing a magnet roll (14).
Claim 18
Independent Claim
28 words
An apparatus comprising two or more molds as set forth in any of claims 4 to 15, wherein one first magnet means (6d) is shared by adjacent molds.
References Cited (Backward Citations)
No citation records indexed.
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