EP0318131A1 - Procédé et dispositif de fabrication d'aimants permanents extrudés - Google Patents

Procédé et dispositif de fabrication d'aimants permanents extrudés Download PDF

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Publication number
EP0318131A1
EP0318131A1 EP88304916A EP88304916A EP0318131A1 EP 0318131 A1 EP0318131 A1 EP 0318131A1 EP 88304916 A EP88304916 A EP 88304916A EP 88304916 A EP88304916 A EP 88304916A EP 0318131 A1 EP0318131 A1 EP 0318131A1
Authority
EP
European Patent Office
Prior art keywords
core
permanent magnet
charge
container
assembly
Prior art date
Legal status (The legal status 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 status listed.)
Granted
Application number
EP88304916A
Other languages
German (de)
English (en)
Other versions
EP0318131B1 (fr
Inventor
Vijay K. Chandhok
Robert F. Krause
Bao-Min Ma
John J. Duplessis
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Crucible Materials Corp
Original Assignee
Crucible Materials Corp
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 Crucible Materials Corp filed Critical Crucible Materials Corp
Priority to AT88304916T priority Critical patent/ATE87764T1/de
Publication of EP0318131A1 publication Critical patent/EP0318131A1/fr
Application granted granted Critical
Publication of EP0318131B1 publication Critical patent/EP0318131B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • H01F1/06—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 in the form of particles, e.g. powder
    • H01F1/08—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 in the form of particles, e.g. powder pressed, sintered, or bound together
    • H01F1/083—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 in the form of particles, e.g. powder pressed, sintered, or bound together in a bonding agent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/20—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by extruding
    • 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
    • H01F41/0266—Moulding; Pressing

Definitions

  • This invention relates to a method and assembly for producing extruded permanent magnet articles from particle charges of permanent magnet alloys.
  • Uniaxial anisotropic crystal alignment is not always advantageous for magnet applications for rotating machinery, motor rotors, beam focussing devices and the like.
  • a [100] fibre texture wherein the C crystallographic axis is perpendicular to the axis of the magnet may be desired.
  • One of the primary applications for magnets of this construction is for use in DC motors.
  • multiple segments of uniaxial anistropic magnets are needed to form the armature for the motor, which segments are identified as 2 positioned around a motor shaft 4 in Fig. 1.
  • Cylindrical, extruded magnets as shown in Fig. 2, are conventionally produced by the use of a cylindrical extrusion container. Magnet alloy particles are introduced to the container, and the container is outgassed, evacuated and sealed. Thereafter, the container is heated to extrusion temperature and extruded to consolidate the particles to substantially full density.
  • the hollow centre of the magnet is achieved by the use of a solid cylinder or mandrel of a diameter corresponding to the internal diameter of the magnet to be produced, which cylinder is attached to the extrusion ram. This solid cylinder moves with the extrusion ram during the extrusion operation and thereby maintains the desired inner diameter of the extruded magnet.
  • Another object of the invention is a method and assembly for use therewith that enables the production of a complete assembly, including a permanent magnet and associated shaft in a single extrusion operation.
  • a particle charge is provided of a permanent magnet alloy composition from which the permanent magnet article is to be made.
  • the particle charge is placed in a cylindrical container having a generally axially positioned core with the charge surrounding the core within the container.
  • the container is evacuated and sealed against the atmosphere.
  • the container and particle charge are heated to elevated temperature and the container and charge are then extruded to compact the charge to substantially full density to thereby produce a substantially fully dense permanent magnet article.
  • a separating medium such as magnesium oxide, may be provided on the core.
  • the core may be of carbon steel, a soft magnet material or stainless steel. During the extrusion operation, the core may be bonded to the permanent magnet alloy. This is advantageous from the standpoint of producing a unitary magnet and shaft assembly during the extrusion operation.
  • Extrusion ratios within the range of 1.5:1 to 50:1 may be employed with extrusion temperatures within the range of 500 to 1200°C.
  • the method of the invention finds particular use in producing rare earth element containing permanent magnets. More specifically, it may be used in the production of magnets of this type wherein at least one rare earth element, such as samarium, neodymium and dysprosium, may be used with a transition element, such as iron and cobalt, plus boron and/or carbon.
  • at least one rare earth element such as samarium, neodymium and dysprosium
  • a transition element such as iron and cobalt, plus boron and/or carbon.
  • the invention also provides an assembly for use in producing a compacted, fully dense permanent magnet article by extrusion including a cylindrical container having a core generally axially positioned therein.
  • the mandrel defines an annular chamber within the container.
  • a particle charge of a permanent magnet alloy from which the article is to be made is provided within this annular chamber.
  • Means are provided for sealing the annular chamber.
  • a separating medium may be provided on the core. This facilitates removal of the core from the compacted magnet after extrusion.
  • the core may be constructed of carbon steel, a soft magnet material or stainless steel.
  • a cylindrical container 8 having end plates 10 with axial openings 11 connected at opposite ends of the container, as by welding (not shown) to seal the container.
  • a solid core 12 is connected at opposite ends thereof to the plates 10 and a portion extends through openings 11.
  • the core is axially positioned within the container 8 to define therein an annular chamber 14 surrounding the core. Particles P of the magnet alloy composition from which the magnet is to be constructed are provided within the annular chamber 14 of the container 8.
  • Figs.3 and 4 so constructed is then after outgassing heated to extrusion temperature and extruded in conventional extruding apparatus to compact the particles in the container to substantially full density.
  • the core 12 may be removed from the compacted hollow cylindrical magnet. This may be facilitated by having the core provided with a separating medium, such as magnesium oxide, on the surface thereof. Alternately, the core may be bonded to the cylindrical magnet for use as an assembly in the production of a conventional motor rotor, as shown in Fig. 2.
  • a carbon steel extrusion container was made with a solid low-carbon rod, 3/4" (19mm) in diameter, welded axially to the top and bottom plates of a mild carbon steel can.
  • Atomized (NdDy)15Fe79B6 powder was put into the 3-1/8" (79.38mm) diameter can and the can was heated to 150°C, evacuated and sealed. The container was then heated to 927°C and extruded with a ratio of 13.8:1.
  • the final extrusion consisted of a 0.3" (7.62mm) diameter steel rod surrounded by a ring shaped magnet with a wall thickness of about 0.25" (6.35mm).
  • the magnetic properties are listed in Table 1. The identical properties along two orthogonal directions perpendicular to the extrusion direction indicates that a [100] fibre texture is obtained. This is the same magnetic behaviour as is observed for magnets extruded by conventional methods.
  • Example 1 To compare the practice of Example 1 with a conventional practice, the identical powder used in Example 1, (NdDy) 15FE79B6, was placed into a 3-1/8" (79.38mm) diameter can and the can was heated to 150°C, evacuated and sealed. The can was then heated to 927°C and extruded with a ratio of 13.8:1.
  • the magnetic properties of the resultant solid cylinder are presented in Table II. The magnetic properties are very similar to those obtained in Example 1.
  • the extrusion technique of Example 1 in accordance with the invention will produce magnetic properties comparable to a conventional magnet extrusion method.
  • the same powder as used in Examples 1 and 2 was placed in a carbon steel extrusion container.
  • This extrusion container was in the shape of a hollow circular cylinder, 3-1/8" (79.38mm) OD and 3/4" (19mm) ID.
  • the container was evacuated, sealed and heated to 927°C and extruded at a 10:1 extrusion ratio.
  • the inner diameter was maintained during extrusion by affixing a solid mandrel to the ram of the extrusion press in accordance with conventional practice.
  • the magnetic properties, Table III are similar to the properties presented in Tables I and II.
  • the invention provides for the production of a hollow permanent magnet by an extrusion practice wherein the desired dimensions of the magnet may be maintained while achieving permanent magnet properties comparable to conventional practices used for this purpose.
  • the shape of the core may include symmetrical geometries other than cylindrical.
  • the particles of magnetic material for compaction may be produced by atomization, rapidly solidified ribbon, cast and pulverized particles, direct cast ingots or particles made by a reduction-­diffusion practice.
  • an assembly may be produced having an outer shell of a permanent magnet alloy and a soft magnetic inner core, with the inner core acting to direct magnetic flux.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)
  • Powder Metallurgy (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
EP88304916A 1987-11-18 1988-05-31 Procédé et dispositif de fabrication d'aimants permanents extrudés Expired - Lifetime EP0318131B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88304916T ATE87764T1 (de) 1987-11-18 1988-05-31 Verfahren und vorrichtung zur herstellung von stranggepressten koerpern aus dauermagnetischem material.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US12235187A 1987-11-18 1987-11-18
US122351 1998-07-24

Publications (2)

Publication Number Publication Date
EP0318131A1 true EP0318131A1 (fr) 1989-05-31
EP0318131B1 EP0318131B1 (fr) 1993-03-31

Family

ID=22402192

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88304916A Expired - Lifetime EP0318131B1 (fr) 1987-11-18 1988-05-31 Procédé et dispositif de fabrication d'aimants permanents extrudés

Country Status (6)

Country Link
EP (1) EP0318131B1 (fr)
JP (1) JPH01151216A (fr)
AT (1) ATE87764T1 (fr)
CA (1) CA1301602C (fr)
DE (1) DE3879886T2 (fr)
ES (1) ES2040341T3 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10312102B4 (de) * 2003-03-19 2015-10-08 Robert Bosch Gmbh Vorrichtung zur Messung eines Füllstandes einer Flüssigkeit in einem Behälter

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3447230A (en) * 1967-01-05 1969-06-03 Sylvania Electric Prod Art of making seamless hollow bodies from sinterable powders
US3918867A (en) * 1969-06-28 1975-11-11 Philips Corp Device for extruding permanent magnet bodies
GB1534221A (en) * 1977-07-25 1978-11-29 Ipari Szerelveny & Gepgyar Process for the production of sleeves and like workpieces from hard metals of high cobalt content
EP0092422A2 (fr) * 1982-04-19 1983-10-26 Matsushita Electric Industrial Co., Ltd. Aimant permanent en alliage de Mn-Al-C et procédé de fabrication
US4640815A (en) * 1985-10-17 1987-02-03 Crucible Materials Corporation Method and assembly for producing extrusion-clad tubular product
EP0231620A2 (fr) * 1986-01-29 1987-08-12 General Motors Corporation Fabrication d'un aimant permanent à partir d'un alliage cristallin à coercitivité très faible de terre rare-métal de transition-bore
EP0240420A1 (fr) * 1986-03-29 1987-10-07 Shin-Etsu Chemical Co., Ltd. Procédé pour la fabrication d'une barre extrudée de longueur continue en aimant plastique avec aimantation multipolaire en périphérie

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5120592A (en) * 1974-08-13 1976-02-18 Matsushita Electric Industrial Co Ltd Kyojiseitaifunmatsuno jikaichuseikeiyokanagata
JPS5176108A (ja) * 1974-12-27 1976-07-01 Hitachi Metals Ltd Funmatsuyakinhonyorukanseizoho oyobifunmatsujutenyoki
JPS60214515A (ja) * 1984-04-10 1985-10-26 Seiko Epson Corp 円筒状永久磁石の製造方法
JPH0626169B2 (ja) * 1984-12-27 1994-04-06 ティーディーケイ株式会社 希土類磁石の磁場中成型方法及び装置
US4602952A (en) * 1985-04-23 1986-07-29 Cameron Iron Works, Inc. Process for making a composite powder metallurgical billet

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3447230A (en) * 1967-01-05 1969-06-03 Sylvania Electric Prod Art of making seamless hollow bodies from sinterable powders
US3918867A (en) * 1969-06-28 1975-11-11 Philips Corp Device for extruding permanent magnet bodies
GB1534221A (en) * 1977-07-25 1978-11-29 Ipari Szerelveny & Gepgyar Process for the production of sleeves and like workpieces from hard metals of high cobalt content
EP0092422A2 (fr) * 1982-04-19 1983-10-26 Matsushita Electric Industrial Co., Ltd. Aimant permanent en alliage de Mn-Al-C et procédé de fabrication
US4640815A (en) * 1985-10-17 1987-02-03 Crucible Materials Corporation Method and assembly for producing extrusion-clad tubular product
EP0231620A2 (fr) * 1986-01-29 1987-08-12 General Motors Corporation Fabrication d'un aimant permanent à partir d'un alliage cristallin à coercitivité très faible de terre rare-métal de transition-bore
EP0240420A1 (fr) * 1986-03-29 1987-10-07 Shin-Etsu Chemical Co., Ltd. Procédé pour la fabrication d'une barre extrudée de longueur continue en aimant plastique avec aimantation multipolaire en périphérie

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, vol. 7, no. 4 (E-151)[1149], 8th January 1983; & JP-A-57 164 509 (FUJI XEROX K.K.) 09-10-1982 *
PATENT ABSTRACTS OF JAPAN, vol. 8, No. 213 (E-269)[1650], 28th September 1984; & JP-A-59 99 705 (SUWA SEIKOSHA K.K.) 08-06-1984 *

Also Published As

Publication number Publication date
JPH01151216A (ja) 1989-06-14
DE3879886T2 (de) 1993-08-26
ES2040341T3 (es) 1993-10-16
EP0318131B1 (fr) 1993-03-31
DE3879886D1 (de) 1993-05-06
CA1301602C (fr) 1992-05-26
ATE87764T1 (de) 1993-04-15

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