EP0255613A2 - Process for manufacturing bipolar or multipolar permanent magnets with a high magnetic energy density - Google Patents

Process for manufacturing bipolar or multipolar permanent magnets with a high magnetic energy density Download PDF

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Publication number
EP0255613A2
EP0255613A2 EP87109822A EP87109822A EP0255613A2 EP 0255613 A2 EP0255613 A2 EP 0255613A2 EP 87109822 A EP87109822 A EP 87109822A EP 87109822 A EP87109822 A EP 87109822A EP 0255613 A2 EP0255613 A2 EP 0255613A2
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Prior art keywords
powder
magnets
permanent magnets
energy density
magnetic
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EP87109822A
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German (de)
French (fr)
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EP0255613B1 (en
EP0255613A3 (en
Inventor
Hans E. Ing. Vogt
Valentin Dipl.-Ing. Tanach
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Vogt Electronic AG
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Vogt Electronic AG
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Classifications

    • 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
    • B22F3/22—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip
    • B22F3/225—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip by injection molding
    • 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
    • B22F3/22—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip
    • 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
    • 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
    • H01F1/10—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 non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure
    • H01F1/11—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 non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure in the form of particles
    • H01F1/113—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 non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure in the form of particles in a bonding agent
    • 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
    • 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
    • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy

Definitions

  • the invention relates to a method for producing anisotropic permanent magnets of various shapes with a high magnetic energy density, these magnets being able to be oriented axially, radially or laterally with any number of pole pairs.
  • the various processes for producing the anisotropic permanent magnets are known.
  • the most commonly used process for the production of sintered anisotropic permanent magnets from powders is the pressing in a magnetic field and the subsequent sintering of the pressed parts.
  • Permanent magnets of various types are produced with a preferred direction in the pressing direction or transversely to the pressing direction.
  • Methods for pressing permanent magnets with a radial preferred direction from powders are restricted for magnets with a low height / diameter ratio or have weak magnetic properties.
  • Methods are also known for pressing pole-oriented ring magnets. These methods are disadvantageous due to the filling problems, poor orientation and cracks in the sintered parts.
  • Another method of making the sintered anisotropic magnets is the extrusion process. This process creates some radial anisotropy, but the resulting energy density is only slightly higher than that of the isotropic magnets.
  • a known method for the production of the anisotropic permanent magnets from powders is the binding of the powders with plastic and processing of the mass by pressing, spraying, calendering or extruding and impressing the preferred direction with mechanical or magnetic methods.
  • anisotropic plastic-bonded permanent magnets show generally better properties than the isotropic permanent magnets made of the same magnetic material and can also have different preferred directions, axially, diametrically, radially, multipole on the circumference. Due to the embedding in the plastic, the energy density is limited and the high values, such as those of the corresponding sintered permanent magnets, can never be achieved.
  • a method for the production of permanent magnets from hard ferrite with radial anisotropy by mixing the ferrite powder with a plastic, then calendering in foils under a magnetic field, then wound on a mandrel under pressure and a magnetic field, then the plastic is removed and finally sintered.
  • the magnetic values given are good, but the process is complicated and very complex and is only suitable for the radial preferred direction of the magnets.
  • the invention has for its object to develop an economical method, which on the one hand the most varied types of anisotropy embossing are possible (axial, diametrical, radial and in particular multi-pole laterally) and on the other hand achieve the high energy densities that are achieved with sintered anisotropic magnets, e.g. with axial preferential direction, are common.
  • the embossed orientation is not impaired by the sintering, so that the magnetic properties along the magnetic paths present during spraying have a complete anisotropy.
  • the magnetic values are similar to the anisotropic pressed and sintered magnets with axial anisotropy.
  • the method can be used for permanent magnets made from barium or strontium ferrite powder, from metal alloy powder, and also from rare earth magnet powder.
  • the magnetic properties are the same as above.

Abstract

A process is described for manufacturing anisotropic sintered magnets by thermoplastic deformation.

Description

Die Erfindung betrifft ein Verfahren zur Herstellung von anisotropen Dauermagneten verschiedenster Formen mit hoher magnetischer Energiedichte, wobei diese Magnete axial, radial oder lateral mit einer beliebigen Polpaarzahl vorzugsgerichtet werden können.The invention relates to a method for producing anisotropic permanent magnets of various shapes with a high magnetic energy density, these magnets being able to be oriented axially, radially or laterally with any number of pole pairs.

Bekannt sind die verschiedenen Verfahren zur Herstellung der anisotropen Dauermagnete. Das meist verwendete Verfahren für die Herstellung von gesinterten anisotropen Dauermagneten aus Pulvern ist das Pressen im Magnetfeld und das anschließende Sintern der gepreßten Teile. So werden Dauermagnete verschiedener Art mit Vorzugsrichtung in der Preßrichtung oder quer zur Preßrichtung hergestellt. Verfahren zum.Pressen von Dauermagneten mit radialer Vorzugsrichtung aus Pulvern sind eingeschränkt für Magnete mit niedrigem Höhe/Durchmesser-Verhältnis-oder weisen schwache magnetische Eigenschaften auf. Es sind auch Verfahren bekannt für das Pressen von polorientierten Ringmagneten. Diese Verfahren sind nachteilig durch die Füllungsprobleme, schwache Orientierung und Risse bei den gesinterten Teilen.The various processes for producing the anisotropic permanent magnets are known. The most commonly used process for the production of sintered anisotropic permanent magnets from powders is the pressing in a magnetic field and the subsequent sintering of the pressed parts. Permanent magnets of various types are produced with a preferred direction in the pressing direction or transversely to the pressing direction. Methods for pressing permanent magnets with a radial preferred direction from powders are restricted for magnets with a low height / diameter ratio or have weak magnetic properties. Methods are also known for pressing pole-oriented ring magnets. These methods are disadvantageous due to the filling problems, poor orientation and cracks in the sintered parts.

Ein anderes Verfahren zur Herstellung der gesinterten anisotropen Magnete ist das Strangziehverfahren. Durch dieses Verfahren wird eine gewisse radiale Anisotropie erzeugt, aber die resultierende Energiedichte ist nur etwas höher als bei den isotropen Magneten.Another method of making the sintered anisotropic magnets is the extrusion process. This process creates some radial anisotropy, but the resulting energy density is only slightly higher than that of the isotropic magnets.

Ein bekanntes Verfahren für die Herstellung der anisotropen Dauermagnete aus Pulvern ist die Bindung der Pulver mit Kunststoff und Bearbeitung der Masse durch Pressen, Spritzen, Kalandrieren oder Extrudieren und Einprägung der Vorzugrichtung mit mechanischen oder magdetischen Methoden.A known method for the production of the anisotropic permanent magnets from powders is the binding of the powders with plastic and processing of the mass by pressing, spraying, calendering or extruding and impressing the preferred direction with mechanical or magnetic methods.

Diese anisotropen kunststoffgebundenen Dauermagnete zeigen

Figure imgb0001
der Regel bessere Eigenschaften als die isotropen Dauermagnete aus dem gleichen magnetischen Werkstoff und können auch verschiedene Vorzugsrichtungen aufweisen, axial, diametral, radial, mehrpolig am Umfang. Durch die Einbettung im Kunststoff ist aber die Energiedichte begrenzt und die hohen Werte, wie die der entsprechenden gesinterten Dauermagnete, können nie erreicht werden.These anisotropic plastic-bonded permanent magnets show
Figure imgb0001
generally better properties than the isotropic permanent magnets made of the same magnetic material and can also have different preferred directions, axially, diametrically, radially, multipole on the circumference. Due to the embedding in the plastic, the energy density is limited and the high values, such as those of the corresponding sintered permanent magnets, can never be achieved.

Ein Verfahren wurde vorgeschlagen für die Herstellung von Dauermagneten aus Hartferrit mit radialer Anisotropie, indem das Ferritpulver mit einem Kunststoff gemischt, dann kalandriert in Folien unter Magnetfeld, dann auf einem Dorn unter Druck und Magnetfeld gewickelt, dann der Kunststoff beseitigt und endlich gesintert wird. Die angegebenen magnetischen Werte sind gut, aber das Verfahren ist kompliziert und sehr aufwendig und ist nur für radiale Vorzugsrichtung der Magnete geeignet.A method has been proposed for the production of permanent magnets from hard ferrite with radial anisotropy by mixing the ferrite powder with a plastic, then calendering in foils under a magnetic field, then wound on a mandrel under pressure and a magnetic field, then the plastic is removed and finally sintered. The magnetic values given are good, but the process is complicated and very complex and is only suitable for the radial preferred direction of the magnets.

Zusammenfassung der ErfindungSummary of the invention

Der Erfindung liegt die Aufgabe zugrunde, ein wirtschaftliches Verfahren zu entwickeln, wodurch einerseits die verschiedensten Arten von Anisotropieprägung möglich sind (axial, diametral, radial und insbesondere mehrpolig lateral) und andererseits die hohen Energiedichten erreichen, die bei gesinterten anisotropen Magneten, z.B. mit axialer Vorzugsrichtung, üblich sind.The invention has for its object to develop an economical method, which on the one hand the most varied types of anisotropy embossing are possible (axial, diametrical, radial and in particular multi-pole laterally) and on the other hand achieve the high energy densities that are achieved with sintered anisotropic magnets, e.g. with axial preferential direction, are common.

Das Verfahren nach der Erfindung besteht aus folgenden Stufen:

  • - Das dauermagnetische Pulver mit Kunststoffen (Polyamide, Polyurethane, Polypropylen, Polyethylen, Polystyrol etc.) in einem Gewichtsverhältnis Pulver/Kunststoff von 1:1 bis 20:1 mischen und granulieren.
  • - Das so entstandene Granulat im Magnetfeld thermoplastisch in die gewünschte Form spritzen, wobei die im Endzustand gewünschten Vorzugsrichtungen eingeprägt werden.
  • - Die gespritzten Teile werden anschließend gesintert und evtl. weiter mechanisch bearbeitet (geschliffen).
  • - Magnetisierung der gesinterten Magnete mit Rücksicht auf die eingeprägten Pole.
The method according to the invention consists of the following stages:
  • - Mix and granulate the permanent magnetic powder with plastics (polyamides, polyurethanes, polypropylene, polyethylene, polystyrene etc.) in a powder / plastic weight ratio of 1: 1 to 20: 1.
  • - Thermoplastic inject the resulting granulate into the desired shape in the magnetic field, the preferred directions desired in the final state being impressed.
  • - The molded parts are then sintered and possibly further machined (ground).
  • - Magnetization of the sintered magnets in consideration of the embossed poles.

Überraschenderweise wurde festgestellt, daß die eingeprägte Orientierung durch das Sintern nicht beeinträchtigt wird, so daß die magnetischen Eigenschaften entlang den beim Spritzen vorhandenen magnetischen Wegen eine vollständige Anisotropie aufweisen. Die magnetischen Werte liegen ähnlich den anisotropen gepreßten und gesinterten Magneten mit axialer Anisotropie.Surprisingly, it was found that the embossed orientation is not impaired by the sintering, so that the magnetic properties along the magnetic paths present during spraying have a complete anisotropy. The magnetic values are similar to the anisotropic pressed and sintered magnets with axial anisotropy.

Das Verfahren kann für Dauermagnete aus Barium-oder StrontiumFerritpulver, aus Metallegierungspulver, ebenso auch aus Seltenerdmagnetpulvern angewendet werden.The method can be used for permanent magnets made from barium or strontium ferrite powder, from metal alloy powder, and also from rare earth magnet powder.

Beispielexample

Aus Sr-Ferritpulver durch'Pressen hergestellte Dauermagnete mit axialer Anisotropie zeigen folgende magnetische Eigenschaften:

  • Remanenz Br = 390 mT
  • Koerzitivfeldstärke BHc = 265 kA/m
  • Koerzitivfeldstärke JHc = 272 kA/m
  • Max. Energiedichte (BH) max = 28 kJ/m3
Permanent magnets with axial anisotropy made from Sr ferrite powder by pressing show the following magnetic properties:
  • Remanence B r = 390 mT
  • Coercive force B H c = 265 kA / m
  • Coercive force J H c = 272 kA / m
  • Max. Energy density (BH) max = 28 kJ / m 3

Aus gleichem Ferritpulver mit Kunststoff gemischt (Verhältnis 88 Gew% Ferritpulver/12 Gew% Kunststoff) und granuliert, werden Ringmagnete gespritzt mit folgenden Abmessungen (im Endzustand): Da = 13 mm, Di = 8 mm, H = 20 mm, unter Magnetfeld mit Einprägung von 12 Polen am Ringumfang, gesintert und geschliffen. Die magnetischen Eigenschaften sind die gleichen wie oben.From the same ferrite powder mixed with plastic (ratio 88% by weight ferrite powder / 12% by weight plastic) and granulated, ring magnets are injection molded with the following dimensions (in the final state): Da = 13 mm, Di = 8 mm, H = 20 mm, with a magnetic field with Embossing of 12 poles on the circumference of the ring, sintered and ground. The magnetic properties are the same as above.

Außerdem wird nach 12-poliger Magnetisierung am Umfang der Ringmagnete eine Induktion von ca. 200 mT gemessen.In addition, an induction of approx. 200 mT is measured on the circumference of the ring magnets after 12-pole magnetization.

Claims (7)

1. Verfahren zur Herstellung anisotroper Dauermagnete mit hoher Energiedichte aus Pulver, dadurch gekennzeichnet, daß das zur Magnetherstellung eingesetzte Pulver der Reihe nach folgendem Fertigungsprozeß unterworfen wird: Mischen mit geeignetem Kunststoff unter Wärmeanwendung, Granulieren dieses Compounds, thermoplastisches Verspritzen in gewünschte Form unter Beaufschlagung mit einem oder mehreren Magnetfeldern zur Einprägung der gewünschten Vorzugsrichtung(en), Sintern, ggf. mechanisch nacharbeiten (z.B.. schleifen) und entsprechend der Polprägung aufmagnetisieren. 1. A process for producing anisotropic permanent magnets with a high energy density from powder, characterized in that the powder used for magnet production is subjected to the following series of manufacturing processes: Mixing with suitable plastic using heat, granulating this compound, thermoplastic spraying in the desired shape with exposure to one or more magnetic fields to impress the desired preferred direction (s), sintering, if necessary reworking mechanically (e.g. grinding) and magnetizing according to the pole stamping. 2. Verfahren nach Anspruch 1 dadurch gekennzeichnet, daß das verwendete Magnetpulver Barium- oder Strontiumferritpulver ist.2. The method according to claim 1, characterized in that the magnetic powder used is barium or strontium ferrite powder. 3. Verfahren nach Anspruch 1 dadurch gekennzeichnet, daß das verwendete Magnetpulver metallisches Legierungspulver (Al, Ni Co o.ä.) ist.3. The method according to claim 1, characterized in that the magnetic powder used is metallic alloy powder (Al, Ni Co or the like). 4. Verfahren nach Anspruch 1 dadurch gekennzeichnet, daß das verwendete Magnetpulver Seltenerd-Magnetpulver (Sa, Ne o,ä.) ist.4. The method according to claim 1, characterized in that the magnetic powder used is rare earth magnetic powder (Sa, Ne o, Ä.). 5. Verfahren nach einem oder mehreren der vorangegangenen Ansprüche dadurch gekennzeichnet, daß das Gewichtsverhältnis Pulver zu Kunststoff 1:1 bis 20:1 beträgt.5. The method according to one or more of the preceding claims, characterized in that the weight ratio of powder to plastic is 1: 1 to 20: 1. 6. Verfahren nach einem oder mehreren der vorangegangenen Ansprüche dadurch gekennzeichnet, daß die Vorzugsrichtung der so hergestellten Magnete axial, diametral, radial, lateral ein- oder mehrpolig ist.6. The method according to one or more of the preceding claims, characterized in that the preferred direction of the magnets thus produced is axially, diametrically, radially, laterally one or more poles. 7. Magnete jeglicher Konfiguration, die nach einem oder mehreren Ansprüchen 1 - 6 hergestellt sind.7. Magnets of any configuration made according to one or more of claims 1-6.
EP19870109822 1986-08-04 1987-07-08 Process for manufacturing bipolar or multipolar permanent magnets with a high magnetic energy density Revoked EP0255613B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19863626360 DE3626360C2 (en) 1986-08-04 1986-08-04 Manufacturing process for two-pole and multi-pole permanent magnets with high magnetic energy density
DE3626360 1986-08-04

Publications (3)

Publication Number Publication Date
EP0255613A2 true EP0255613A2 (en) 1988-02-10
EP0255613A3 EP0255613A3 (en) 1988-07-13
EP0255613B1 EP0255613B1 (en) 1992-05-13

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EP19870109822 Revoked EP0255613B1 (en) 1986-08-04 1987-07-08 Process for manufacturing bipolar or multipolar permanent magnets with a high magnetic energy density

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0355704A1 (en) * 1988-08-18 1990-02-28 Hitachi Metals, Ltd. Anisotropic rare-earth permanent magnets and method for making same
EP0331055B1 (en) * 1988-02-29 1994-01-12 Matsushita Electric Industrial Co., Ltd. Methods for producing a resinbonded magnet
DE102008052804A1 (en) * 2008-10-22 2010-04-29 Windhorst Beteiligungsgesellschaft Mbh Magnetic rotary encoder for detection of angle- or rotation of shaft in e.g. household appliance, has front side at which angle sensors are fixedly arranged on rotational axis, where encoder is made of anisotropic hard ferrite
US10035095B2 (en) 2016-03-04 2018-07-31 General Electric Company Diverted pulse jet cleaning device and system
US20190143569A1 (en) * 2015-10-09 2019-05-16 Lexmark International, Inc. Injection-Molded Physical Unclonable Function

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4420318C2 (en) * 1994-06-11 1996-04-11 Schulman A Gmbh Polymer-based composition for the production of magnetic and magnetizable moldings
DE4434471C1 (en) * 1994-09-27 1996-03-28 Bosch Gmbh Robert Process for the production of moldings from hard ferrites
WO2012057961A2 (en) 2010-10-27 2012-05-03 Kraft Foods Global Brands Llc Magnetically closable product accommodating package

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DE1464249A1 (en) * 1963-11-16 1969-02-20 Leyman Corp Process for the production of permanent magnets
US3596350A (en) * 1968-05-08 1971-08-03 Magnetfab Bonn Gmbh Process for the production of permanent magnets from anisotropic permanent magnet powder
DE3120501A1 (en) * 1981-05-22 1982-12-09 MTU Motoren- und Turbinen-Union München GmbH, 8000 München "METHOD AND DEVICE FOR PRODUCING MOLDED PARTS"

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DE1284531B (en) * 1957-04-27 1968-12-05 Baermann Max Method and device for the production of plastic-bonded anisotropic permanent magnets
DE2401934C3 (en) * 1974-01-16 1981-05-14 Fuji Electrochemical Co., Ltd., Tokyo Method of manufacturing an anisotropic ferrite magnet
DE3021607A1 (en) * 1980-06-09 1981-12-17 Philips Patentverwaltung Gmbh, 2000 Hamburg Permanent magnet rotor for electrical machines - esp. bicycle dynamo, using ferrite magnet which is either sintered or bonded with polymer, and is joined to stub axle
DE3047701A1 (en) * 1980-12-18 1982-07-15 Magnetfabrik Bonn Gmbh Vorm. Gewerkschaft Windhorst, 5300 Bonn METHOD FOR PRODUCING ANISOTROPAL PERMANENT MAGNETS AND TUBULAR PERMANENT MAGNETS PRODUCED THEREFORE

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1464249A1 (en) * 1963-11-16 1969-02-20 Leyman Corp Process for the production of permanent magnets
US3596350A (en) * 1968-05-08 1971-08-03 Magnetfab Bonn Gmbh Process for the production of permanent magnets from anisotropic permanent magnet powder
DE3120501A1 (en) * 1981-05-22 1982-12-09 MTU Motoren- und Turbinen-Union München GmbH, 8000 München "METHOD AND DEVICE FOR PRODUCING MOLDED PARTS"

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0331055B1 (en) * 1988-02-29 1994-01-12 Matsushita Electric Industrial Co., Ltd. Methods for producing a resinbonded magnet
EP0355704A1 (en) * 1988-08-18 1990-02-28 Hitachi Metals, Ltd. Anisotropic rare-earth permanent magnets and method for making same
DE102008052804A1 (en) * 2008-10-22 2010-04-29 Windhorst Beteiligungsgesellschaft Mbh Magnetic rotary encoder for detection of angle- or rotation of shaft in e.g. household appliance, has front side at which angle sensors are fixedly arranged on rotational axis, where encoder is made of anisotropic hard ferrite
US20190143569A1 (en) * 2015-10-09 2019-05-16 Lexmark International, Inc. Injection-Molded Physical Unclonable Function
US11356287B2 (en) 2015-10-09 2022-06-07 Lexmark International, Inc. Injection-molded physical unclonable function
US10035095B2 (en) 2016-03-04 2018-07-31 General Electric Company Diverted pulse jet cleaning device and system

Also Published As

Publication number Publication date
DE3626360C2 (en) 1995-06-22
DE3626360A1 (en) 1988-02-11
EP0255613B1 (en) 1992-05-13
EP0255613A3 (en) 1988-07-13

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