WO1991016717A1 - Procede de fabrication d'aimants en alliage de terres rares de haute energie - Google Patents

Procede de fabrication d'aimants en alliage de terres rares de haute energie Download PDF

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Publication number
WO1991016717A1
WO1991016717A1 PCT/US1991/002679 US9102679W WO9116717A1 WO 1991016717 A1 WO1991016717 A1 WO 1991016717A1 US 9102679 W US9102679 W US 9102679W WO 9116717 A1 WO9116717 A1 WO 9116717A1
Authority
WO
WIPO (PCT)
Prior art keywords
rare earth
earth alloy
high energy
mixture
mold
Prior art date
Application number
PCT/US1991/002679
Other languages
English (en)
Inventor
J. Kelly Lee
Svetlana Reznik
Original Assignee
Eastman Kodak Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eastman Kodak Company filed Critical Eastman Kodak Company
Publication of WO1991016717A1 publication Critical patent/WO1991016717A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/0273—Imparting anisotropy
    • H01F41/028—Radial anisotropy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
    • H01F1/0578—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together bonded together
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F13/00—Apparatus or processes for magnetising or demagnetising
    • H01F13/003—Methods and devices for magnetising permanent magnets

Definitions

  • This invention relates to methods of making plastic bonded permanent magnets and more particularly to methods of injection molding such plastic bonded magnets employing isotrophic high energy rare earth alloy magnetic materials.
  • High energy rare earth alloy magnetic materials require high magnetizing field strength to magnetize the materials to saturation.
  • rapid solidified NdFeB magnetic material typically requires fields on the order of 3183 KA/m or more to substantially fully saturate the magnetic materials. See published European patent application 0 125 752 A2 published 21.11.84.
  • the present inventors have discovered that under the elevated temperatures and pressures experienced in the injection molding environment, a surprising reduction in the coercivity of high energy rare earth magnetic materials occurs, and it is therefore possible to fully saturate a permanent magnetic material that ordinarily requires fields in acess of 3183 KA/m at room temperature and pressure with fields of only 7.9 KA/m or less.
  • a plastic bonded permanent magnet is formed by injection molding a mixture of high energy rare earth alloy magnetic material (preferably rapid solidified NdFeB) requiring magnetization fields on the order of 3183 KA/m or greater at room temperature and pressure, and thermoplastic powder in a mold having means for providing magnetizing fields of 7.9 KA/m or less, and at a sufficiently elevated temperature and pressure to allow the field to fully magnetize the injection molded magnet, whereby high energy bonded magnets are provided without the need for further magnetization of the finished product.
  • high energy rare earth alloy magnetic material preferably rapid solidified NdFeB
  • Figure 1 is a schematic perspective view of a permanent magnetic roller made according to the method of the present invention
  • Figure 2 is a cross sectional view of an injection mold useful in practicing the method of the present invention
  • Figure 3 is a partial cross sectional view of the injection port of the mold shown in Figure 2.
  • a bonded plastic cylindrical magnet 10 produced according to the present invention is shown.
  • the magnet has longitudinal alternating N and S poles, and is of the type found in rotating motors and employed as toner transport rollers in electrographic apparatus.
  • the roller 10 comprises a mixture of rare earth alloy permanent magnetic powder, preferably rapid solidified NdFeB, in a plastic binder such as nylon.
  • the magnetic alloy material has a coercivity at room temperature and pressure of 3183 KA/m or greater.
  • the magnet is formed in injection molding apparatus having means for molding the material in the presence of a magnetic field of 7.9 KA/m or less, preferably about 477 KA/m, and at an elevated temperature and pressure to fully magnetize the magnetic alloy material.
  • Figure 2 is a cross section of a mold useful in practicing the present invention.
  • the mold comprises a mold body 12 supporting a plurality of soft iron pole pieces 14.
  • the pole pieces 14 are in the shape of rectangular blades that fit into slots in the mold body 12.
  • the mold parts along the line 16.
  • a tube 18 that forms a cylindrical mold cavity.
  • the tube may be nonmagnetic material such as stainless steel or aluminum.
  • the pole pieces 14 are in contact with the outside of the tube 18.
  • the pole pieces 14 are wrapped with high temperature insulated wire coils 20, and sufficient current is supplied to the coils during the molding operation to generate a magnetic field at the pole tips of less than 7.9 KA/m, preferably about 477 KA/m.
  • Figure 3 is a vertical cross section of the molding apparatus shown in Figure 2 at one end thereof. Current is maintained in the coils 20 while the mold fills, and then is terminated. After a short cooling time, the tube 18 is removed from the mold and the magnet 10 is forced from the tube 18. It has been found that the finished magnets can be produced in this manner with no need for further processing or post magnetization.
  • the magnet forming method of the present invention is useful in forming high energy injection molded magnets, and is advantageous in that fully magnetized rare earth magnets are formed in a single injection step with low magnetizing field, without the need for subsequent magnetization steps.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)

Abstract

On forme des aimants de terres rares de haute énergie par moulage par injection et magnétisation (14, 20) dans le moule (12) à une température suffisante pour réduire sensiblement la coercivité de la matière magnétique, de sorte que des aimants de terres rares entièrement magnétiques de haute énergie sont formés en une seule étape de moulage sans post-magnétisation.
PCT/US1991/002679 1990-04-23 1991-04-19 Procede de fabrication d'aimants en alliage de terres rares de haute energie WO1991016717A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US51337190A 1990-04-23 1990-04-23
US513,371 1990-04-23

Publications (1)

Publication Number Publication Date
WO1991016717A1 true WO1991016717A1 (fr) 1991-10-31

Family

ID=24042986

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1991/002679 WO1991016717A1 (fr) 1990-04-23 1991-04-19 Procede de fabrication d'aimants en alliage de terres rares de haute energie

Country Status (3)

Country Link
EP (1) EP0478751A1 (fr)
JP (1) JPH04506887A (fr)
WO (1) WO1991016717A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6076110A (ja) * 1983-10-03 1985-04-30 Sumitomo Special Metals Co Ltd 磁気回路の組立着磁方法
JPS61276303A (ja) * 1985-05-31 1986-12-06 Seiko Epson Corp 希土類永久磁石の製造方法
JPS63216309A (ja) * 1987-03-05 1988-09-08 Seiko Epson Corp 円筒状希土類焼結磁石の製造方法
EP0284033A1 (fr) * 1987-03-23 1988-09-28 Tokin Corporation Méthode pour la fabrication d'un aimant anisotrope à liant, à base de terre rare-fer-bore, à partir de copeaux rubanés en alliage terre rare-fer-bore rapidement trempé
JPH0212801A (ja) * 1988-06-30 1990-01-17 Hitachi Metals Ltd ボンド磁石用コンパウンド及びその製造方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6076110A (ja) * 1983-10-03 1985-04-30 Sumitomo Special Metals Co Ltd 磁気回路の組立着磁方法
JPS61276303A (ja) * 1985-05-31 1986-12-06 Seiko Epson Corp 希土類永久磁石の製造方法
JPS63216309A (ja) * 1987-03-05 1988-09-08 Seiko Epson Corp 円筒状希土類焼結磁石の製造方法
EP0284033A1 (fr) * 1987-03-23 1988-09-28 Tokin Corporation Méthode pour la fabrication d'un aimant anisotrope à liant, à base de terre rare-fer-bore, à partir de copeaux rubanés en alliage terre rare-fer-bore rapidement trempé
JPH0212801A (ja) * 1988-06-30 1990-01-17 Hitachi Metals Ltd ボンド磁石用コンパウンド及びその製造方法

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 11, no. 130 (E-502)(2577) 23 April 1987, & JP-A-61 276303 (SEIKO EPSON CORP) 6 December 1986, see the whole document *
PATENT ABSTRACTS OF JAPAN vol. 13, no. 5 (E-701)(3353) 9 January 1989, & JP-A-63 216309 (SEIKO EPSON CORP) 8 September 1988, see the whole document *
PATENT ABSTRACTS OF JAPAN vol. 14, no. 154 (E-907)(4097) 23 March 1990, & JP-A-2 12801 (HITACHI METALS LTD) 17 January 1990, see the whole document *
PATENT ABSTRACTS OF JAPAN vol. 9, no. 216 (E-340)(1939) 3 September 1985, & JP-A-60 76110 (SUMITOMO) 30 April 1985, see the whole document *

Also Published As

Publication number Publication date
JPH04506887A (ja) 1992-11-26
EP0478751A1 (fr) 1992-04-08

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