EP0478751A1 - Verfahren zur herstellung von seltenerdlegierungsmagneten mit hohem energiegehalt - Google Patents
Verfahren zur herstellung von seltenerdlegierungsmagneten mit hohem energiegehaltInfo
- Publication number
- EP0478751A1 EP0478751A1 EP19910908294 EP91908294A EP0478751A1 EP 0478751 A1 EP0478751 A1 EP 0478751A1 EP 19910908294 EP19910908294 EP 19910908294 EP 91908294 A EP91908294 A EP 91908294A EP 0478751 A1 EP0478751 A1 EP 0478751A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- rare earth
- earth alloy
- high energy
- mixture
- mold
- 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.)
- Withdrawn
Links
- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 14
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 14
- 239000000956 alloy Substances 0.000 title claims description 11
- 229910045601 alloy Inorganic materials 0.000 title claims description 8
- 238000004519 manufacturing process Methods 0.000 title description 3
- 239000000696 magnetic material Substances 0.000 claims abstract description 12
- 238000001746 injection moulding Methods 0.000 claims abstract description 11
- 238000000034 method Methods 0.000 claims description 10
- 239000000203 mixture Substances 0.000 claims description 9
- 230000005291 magnetic effect Effects 0.000 claims description 8
- 239000004033 plastic Substances 0.000 claims description 7
- 229920003023 plastic Polymers 0.000 claims description 7
- 229910001172 neodymium magnet Inorganic materials 0.000 claims description 6
- 239000006247 magnetic powder Substances 0.000 claims description 5
- 239000000843 powder Substances 0.000 claims description 3
- 229920001169 thermoplastic Polymers 0.000 claims description 3
- 239000004416 thermosoftening plastic Substances 0.000 claims description 3
- 239000011230 binding agent Substances 0.000 claims description 2
- 229920002647 polyamide Polymers 0.000 claims description 2
- 230000005415 magnetization Effects 0.000 abstract description 6
- 238000000465 moulding Methods 0.000 abstract description 4
- 238000002347 injection Methods 0.000 description 7
- 239000007924 injection Substances 0.000 description 7
- 229910001004 magnetic alloy Inorganic materials 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- JHWNWJKBPDFINM-UHFFFAOYSA-N Laurolactam Chemical compound O=C1CCCCCCCCCCCN1 JHWNWJKBPDFINM-UHFFFAOYSA-N 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 229920000299 Nylon 12 Polymers 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229920006351 engineering plastic Polymers 0.000 description 1
- 230000005294 ferromagnetic effect Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 229920005596 polymer binder Polymers 0.000 description 1
- 239000002491 polymer binding agent Substances 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
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)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
- Hard Magnetic Materials (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US51337190A | 1990-04-23 | 1990-04-23 | |
| US513371 | 1990-04-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP0478751A1 true EP0478751A1 (de) | 1992-04-08 |
Family
ID=24042986
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP19910908294 Withdrawn EP0478751A1 (de) | 1990-04-23 | 1991-04-19 | Verfahren zur herstellung von seltenerdlegierungsmagneten mit hohem energiegehalt |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0478751A1 (de) |
| JP (1) | JPH04506887A (de) |
| WO (1) | WO1991016717A1 (de) |
Family Cites Families (5)
| 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 |
| DE3883038T2 (de) * | 1987-03-23 | 1994-01-05 | Tokin Corp | Verfahren zur Herstellung eines anisotropen seltene Erden-Eisen-Bor-Verbundmagneten mit Hilfe von bandähnlichen Spänen aus einer seltene Erden-Eisen-Bor-Legierung. |
| 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 |
-
1991
- 1991-04-19 EP EP19910908294 patent/EP0478751A1/de not_active Withdrawn
- 1991-04-19 JP JP3508064A patent/JPH04506887A/ja active Pending
- 1991-04-19 WO PCT/US1991/002679 patent/WO1991016717A1/en not_active Ceased
Non-Patent Citations (1)
| Title |
|---|
| See references of WO9116717A1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04506887A (ja) | 1992-11-26 |
| WO1991016717A1 (en) | 1991-10-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB |
|
| 17P | Request for examination filed |
Effective date: 19920331 |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
|
| 18W | Application withdrawn |
Withdrawal date: 19920926 |