JPH0412010B2 - - Google Patents
Info
- Publication number
- JPH0412010B2 JPH0412010B2 JP55105859A JP10585980A JPH0412010B2 JP H0412010 B2 JPH0412010 B2 JP H0412010B2 JP 55105859 A JP55105859 A JP 55105859A JP 10585980 A JP10585980 A JP 10585980A JP H0412010 B2 JPH0412010 B2 JP H0412010B2
- Authority
- JP
- Japan
- Prior art keywords
- anisotropic
- magnetic
- magnetic field
- powder
- cylindrical
- 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.)
- Expired - Lifetime
Links
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
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Powder Metallurgy (AREA)
- Hard Magnetic Materials (AREA)
Description
（産業上の利用分野）
本発明は粉末成形における酸化物磁性材料の円
筒状異方性永久磁石に係り、特に磁場中成形で放
射状の磁束を有する円筒状異方性永久磁石の製造
法に関するものである。
（従来の技術）
一般に酸化物磁性材料の粉体を金型空〓部に充
填し、その空〓部に磁場を印加し成形する磁場中
成形において、印加磁場強度Ｈにより充填された
磁性粉は磁場方向に異方性化がなされるものであ
る。この異方性化のメカニズムは、磁場中におか
れた磁性粉が第１図に示す如く外部磁界Ｈによつ
て回転することによる。従つて回転のモーメント
Ｍが大きい程、異方性化の度合いが大きくなる。
即ち一般的にモーメントは、次式の如く示され
る。
Ｍ＝Ｈ・ｌ・sinθ Ｈ：磁場強度
ｌ：磁性粉の長さ
θ：磁界に対する磁性粉の傾き
よつて従来は、磁場強度Ｈを向上させることに
よつて回転モーメントを大きくすることが行われ
て来た。しかし円筒状異方性永久磁石の磁場中成
形による製造においては、製品形状の制約、ダイ
ス、コア材の磁気特性の制約等によつて空〓部の
異方性化のため磁場強度に限界があつた。従つて
従来よりこの限界のために十分な磁気特性が得ら
れないので、放射状を有する円筒状異方性永久磁
石は応用面でも問題点があるものである。一方、
弱い磁場強度でモーメントＭ大きくするには、磁
性粉の長さｌを大きくすることが考えられる。し
かし、単一磁区の磁性粉で、その長さｌをモーメ
ントＭが十分な異方性化をするほど大きくするこ
とは出来ないことはないだろうが、生産性に劣る
ものである。
（発明が解決しようとする課題）
本発明は、上記のような問題点を解決し、成形
時に印加する磁場の強さが比較的小さくとも、半
径方向によく異方性の付与された円筒状異方性永
久磁石を提供することを目的とするものである。
また他の目的は異方性造粒粉を分級すると同じに
粉粒体の流動性や充填性を改善して、安定した量
産化の可能な永久磁石の製造法を提供するもので
ある。
（課題を解決するための手段）
本発明の円筒状異方性永久磁石の製造法は、微
粉砕された、Ba、SrあるいはPbのハードフエラ
イト磁性粉を磁場を印加して異方性造粒処理を行
い、異方性造粒粉とし、この32〜200メツシユの
異方性造粒粉を円筒状の成形空〓に充填し、上下
のパンチにより圧縮成形するに際し、充填・成形
の間、磁場強度が3000エルステツド以下の放射状
の異方性磁場を印加し、円筒状の成形体に磁気異
方性を与えた後に、加熱焼結することを特徴とす
るものである。
本発明に使用する異方性造粒粉の粒度は48〜
100メツシユの時に最も好ましい結果が得られる。
（作用）
本発明を図面によつて説明すると、第２図は磁
場中形成装置の縦断面図を示し、第３図は第２図
の形成装置のＡ−Ａ断面図を示す。ダイス１およ
びコア２は支柱１１，１２を介して下部フレーム
８に固着され、下部フレーム８を下部シリンダ９
に接続して摺動可能とする。上部には上パンチ４
を上部フレーム５に固着し、上部フレーム５を上
部シリンダ６に接続して摺動可能とし、また下部
には下パンチ７を基板１３に固定し非摺動とす
る。ダイス１及びコア２と上パンチ４の移動によ
り成形用の空〓部３を形成する。この円環状空〓
部に成形されるフエライト磁粉が充填される。次
にダイス１の内部には磁場を付与するための電磁
コイル１０を２個設置し、ダイス１及びコア２と
上パンチ４とで空〓部３を密閉した時に通電して
矢印方向の磁束が流れ、圧縮が終つた時点で電流
を切り逆方向に電流を流してダイス１およびコア
２と得られる成形体に脱磁できるように接続す
る。ダイス１およびコア２を磁性体とし、上パン
チ４および下パンチ７を非磁性体とし、更に電磁
コイル１０の内側に非磁性体からなるスペーサ１
４を設けているので、電磁コイル１０で誘起され
た磁束はダイス１から空〓部３へ、そしてコア２
へと、矢印で示されるように空〓部３内を半径方
向に流れる。
このような構造において最良の異方性造粒粉を
得るには、スラリー性磁性粉を十分な強い磁場中
において圧縮成形し、造粒に適した成形体強度を
得た後、この成形体を解砕し粉砕粒度を分級する
ことにより本発明に適した造粒粉とすることがで
きる。
次に本発明による実施例を以下に説明すると先
づ磁性粉を例えばSrO・6Fe2O3の平均粒径1μｍ
のものを用い、約10000Oeの磁場強度下、成形密
度約2.3〜3.0ｇ／c.c.で湿式圧搾成形後、解砕し分
級した磁性粉Ｂを得た。また別に微粉としては、
同様に先の磁性粉を用いてアトマイザーとかパル
ペライザー等により十分に解砕して得られる磁性
粉Ｃをそれぞれ製造した。
これ等の磁性粉Ｂ、Ｃを第２図及び第３図に示
す圧縮成形装置の金型に充填し、金型空〓部の磁
場強度Bg≒2000Oeで磁場中成形して得られた成
形体を約1200℃で焼成した後、磁場印加方向のＢ
−Ｈ特性を測定した。その結果を表１に示す。
(Industrial Application Field) The present invention relates to a cylindrical anisotropic permanent magnet made of oxide magnetic material in powder molding, and particularly relates to a method for manufacturing a cylindrical anisotropic permanent magnet having radial magnetic flux by molding in a magnetic field. It is. (Prior art) In general, in magnetic field molding in which powder of an oxide magnetic material is filled into a mold cavity and molded by applying a magnetic field to the cavity, the filled magnetic powder is Anisotropy is created in the direction of the magnetic field. The mechanism of this anisotropy is that magnetic powder placed in a magnetic field is rotated by an external magnetic field H as shown in FIG. Therefore, the greater the rotational moment M, the greater the degree of anisotropy.
That is, the moment is generally expressed as shown in the following equation. M=H・l・sinθ H: Magnetic field strength l: Length of magnetic powder θ: Inclination of magnetic powder with respect to magnetic field Therefore, conventionally, the rotation moment was increased by increasing the magnetic field strength H. I came. However, in manufacturing cylindrical anisotropic permanent magnets by forming in a magnetic field, there is a limit to the magnetic field strength due to the anisotropy of the hollow space due to restrictions on the product shape and the magnetic properties of the die and core material. It was hot. Therefore, conventionally, due to this limit, sufficient magnetic properties cannot be obtained, and therefore, cylindrical anisotropic permanent magnets having a radial shape have problems in terms of application. on the other hand,
In order to increase the moment M with a weak magnetic field strength, it is possible to increase the length l of the magnetic powder. However, although it is possible to make the length l of a single domain magnetic powder large enough to make the moment M sufficiently anisotropic, the productivity is poor. (Problems to be Solved by the Invention) The present invention solves the above-mentioned problems and produces a cylindrical shape with good radial anisotropy even if the strength of the magnetic field applied during molding is relatively small. The purpose is to provide an anisotropic permanent magnet.
Another object of the present invention is to provide a method for producing permanent magnets that can be stably mass-produced by classifying anisotropic granulated powder and improving the fluidity and filling properties of the powder. (Means for Solving the Problems) The method for producing a cylindrical anisotropic permanent magnet of the present invention is to apply a magnetic field to finely pulverized hard ferrite magnetic powder of Ba, Sr, or Pb to form anisotropic granules. This 32 to 200 mesh anisotropic granulated powder is filled into a cylindrical molding cavity and compression molded using upper and lower punches. During filling and molding, It is characterized by applying a radial anisotropic magnetic field with a magnetic field strength of 3000 oers or less to impart magnetic anisotropy to the cylindrical molded body, and then heating and sintering it. The particle size of the anisotropic granulated powder used in the present invention is 48~
The most favorable results are obtained with 100 meshes. (Function) The present invention will be explained with reference to the drawings. FIG. 2 shows a longitudinal sectional view of the forming device in a magnetic field, and FIG. 3 shows a sectional view taken along line A-A of the forming device in FIG. The die 1 and the core 2 are fixed to the lower frame 8 via struts 11 and 12, and the lower frame 8 is connected to the lower cylinder 9.
to enable sliding. Upper punch 4 at the top
is fixed to the upper frame 5, and the upper frame 5 is connected to the upper cylinder 6 so as to be slidable, and the lower punch 7 is fixed to the base plate 13 at the lower part so as not to be slidable. By moving the die 1, core 2, and upper punch 4, a molding cavity 3 is formed. This circular sky
The part is filled with ferrite magnetic powder. Next, two electromagnetic coils 10 are installed inside the die 1 to apply a magnetic field, and when the die 1, core 2, and upper punch 4 seal the empty space 3, electricity is applied to generate magnetic flux in the direction of the arrow. When the current flow and compression are completed, the current is turned off, and the current is passed in the opposite direction to connect the die 1 and core 2 to the resulting molded body in a manner such that they can be demagnetized. The die 1 and the core 2 are made of magnetic material, the upper punch 4 and the lower punch 7 are made of non-magnetic material, and a spacer 1 made of non-magnetic material is provided inside the electromagnetic coil 10.
4, the magnetic flux induced by the electromagnetic coil 10 flows from the die 1 to the hollow part 3, and then to the core 2.
It flows radially within the cavity 3 as shown by the arrows. In order to obtain the best anisotropic granulated powder in such a structure, slurry magnetic powder is compression molded in a sufficiently strong magnetic field to obtain a compact strength suitable for granulation, and then this compact is Granulated powder suitable for the present invention can be obtained by crushing and classifying the pulverized particle size. Next, an example according to the present invention will be explained below. First, the magnetic powder is, for example, SrO.6Fe 2 O 3 with an average particle size of 1 μm.
Magnetic powder B was obtained by wet compression molding at a compacting density of approximately 2.3 to 3.0 g/cc under a magnetic field strength of approximately 10,000 Oe, followed by crushing and classification. In addition, as a fine powder,
Similarly, magnetic powders C were produced by thoroughly crushing the magnetic powders using an atomizer, a pulperizer, or the like. These magnetic powders B and C were filled into the mold of the compression molding apparatus shown in Figs. 2 and 3, and molded in a magnetic field at a magnetic field strength Bg≒2000 Oe in the mold cavity, resulting in a molded product. After firing at about 1200℃, B in the direction of magnetic field application
-H characteristics were measured. The results are shown in Table 1.
【表】【table】
【表】
表１に示す如く磁気特性Brは、異方性造粒粉
が微粉に比較して高く、また異方性造粒粉では48
〜100メツシユにおいてピーク値があることがわ
かる。また異方性造粒粉と微粉を磁場強度を変え
て磁場成形し、その成形体を1240℃で焼結後、磁
気特性（残留磁束密度Br）を測定した結果を第
４図に示す。図でａは異方性造粒粉、ｂは微粉の
場合の特性を示す曲線である。磁場強度Bgが
3000Oe近くまでは、異方性造粒粉の方の特性が
高いが、これは前記したモーメントＭが大きいこ
とによるものである。成形時に印加する磁場強度
が低くとも異方性化がよく進むことがわかる。し
かし、磁場強度が強くなるにつれて単磁区に近い
微粉の方が特性が大きくなつて来ている。異方性
造粒粉は多数の磁性粉から構成されたものであ
り、造粒時に異方性磁場を印加しているがすべて
の磁性粉の磁化が完全には一方向を向かず、一部
分の磁性粉は造粒粉の長さ方向からはずれたもの
がある。このためきわめて強い磁場を印加すれば
造粒していない微粉はよりよく異方性化し磁気特
性が、異方性造粒粉の場合より高くなつているも
のと考えられる。
また、異方性造粒粉の粒度が大きくなるほど、
それを構成している磁性粉のうちその磁化容易軸
を造粒粉の長さ方向からずれた磁性粉の量が増す
ので、異方性化の度合いが低下して来て長さｌが
大きくモーメントＭが大きくなるにもかかわらず
高い特性が得られない。また造粒粉の粒度が小さ
くなると造粒粉内の磁性粉の異方性化は進んでい
るが成形時の異方性磁場の大きさが同じでは成形
品の異方性が悪くなる。このために、異方性造粒
粉の粒度は表１に示すように、32〜200メツシユ、
好ましくは48〜100メツシユがよい。
更に、造粒粉の場合微粉よりも金型への充填時
の流動性が良いものなので、成形時の向上につな
がつてくる。
（発明の効果）
以上説明したように本発明はダイス及びコアと
上、下非磁性パンチで外部よりラジアルな磁場を
発生させながら、充填成形する際に、特定の粒度
をもつた異方性造粒粉を使用するので、下記の効
果を奏し得るものである。
(1) 磁場強度Bgが3000Oe以下の低磁場であつて
も、高い磁気特性を有する円筒状永久磁石が得
られる。
(2) 造粒粉による充填時の粉の流動性が、分級し
てあるために良くなり、成形時に均一な充填が
でき、もつて成形性が向上する。[Table] As shown in Table 1, the magnetic property Br of anisotropic granulated powder is higher than that of fine powder, and that of anisotropic granulated powder is 48
It can be seen that there is a peak value at ~100 meshes. Furthermore, anisotropic granulated powder and fine powder were subjected to magnetic field compaction with varying magnetic field strengths, and after sintering the compact at 1240° C., the magnetic properties (residual magnetic flux density Br) were measured. The results are shown in FIG. In the figure, a is a curve showing the characteristics in the case of anisotropic granulated powder, and b is a curve showing the characteristics in the case of fine powder. The magnetic field strength Bg is
Up to about 3000 Oe, the anisotropic granulated powder has better properties, but this is due to the larger moment M mentioned above. It can be seen that anisotropy progresses well even when the magnetic field strength applied during molding is low. However, as the magnetic field strength increases, the characteristics of fine powder that is close to a single magnetic domain become greater. Anisotropic granulated powder is composed of a large number of magnetic powders, and although an anisotropic magnetic field is applied during granulation, the magnetization of all the magnetic powders does not completely point in one direction, and some Some magnetic powders are deviated from the length direction of the granulated powder. For this reason, it is thought that if an extremely strong magnetic field is applied, the ungranulated fine powder becomes more anisotropic, resulting in higher magnetic properties than in the case of anisotropic granulated powder. In addition, the larger the particle size of the anisotropic granulated powder,
Among the magnetic powders that compose it, the amount of magnetic powder whose axis of easy magnetization is shifted from the length direction of the granulated powder increases, so the degree of anisotropy decreases and the length l increases. Although the moment M becomes large, high characteristics cannot be obtained. Furthermore, as the particle size of the granulated powder becomes smaller, the anisotropy of the magnetic powder in the granulated powder progresses, but if the magnitude of the anisotropic magnetic field during molding remains the same, the anisotropy of the molded product will deteriorate. For this purpose, the particle size of the anisotropic granulated powder is 32 to 200 mesh, as shown in Table 1.
Preferably 48 to 100 meshes. Furthermore, granulated powder has better fluidity when filled into a mold than fine powder, which leads to improved molding. (Effects of the Invention) As explained above, the present invention produces an anisotropic structure with a specific particle size during filling molding while generating a radial magnetic field from the outside using the die, core, and upper and lower nonmagnetic punches. Since grain powder is used, the following effects can be achieved. (1) A cylindrical permanent magnet with high magnetic properties can be obtained even in a low magnetic field where the magnetic field strength Bg is 3000 Oe or less. (2) The fluidity of the powder during filling with granulated powder is improved because it is classified, and uniform filling is possible during molding, thereby improving moldability.
第１図は、磁場中の磁性粉の状況を示す説明
図、第２図は本発明に使用する成形装置の縦断面
図、第３図は第２図のＡ−Ａ断面図、第４図は磁
気特性曲線図である。
１……ダイス、２……コアー、４，７……パン
チ、５，８……フレーム、６，９……シリンダ
ー、１０……磁場コイル。
Fig. 1 is an explanatory diagram showing the state of magnetic powder in a magnetic field, Fig. 2 is a longitudinal sectional view of the molding device used in the present invention, Fig. 3 is a sectional view taken along line A-A in Fig. 2, and Fig. 4 is a magnetic characteristic curve diagram. 1... Dice, 2... Core, 4, 7... Punch, 5, 8... Frame, 6, 9... Cylinder, 10... Magnetic field coil.
Claims (1)
フエライト磁性粉を磁場を印加して異方性造粒処
理を行い、異方性造粒粉とし、この32〜200メツ
シユの異方性造粒粉を円筒状の成形空〓に充填
し、上下のパンチにより圧縮成形するに際し、充
填・成形の間、磁場強度が3000エルステツド以下
の放射状の異方性磁場を印加し、円筒状の成形体
に磁気異方性を与えた後に、加熱焼結することを
特徴とする円筒状異方性永久磁石の製造法。 ２ 特許請求の範囲第１項において、48〜100メ
ツシユの異方性造粒粉を用いて成形することを特
徴とする円筒状異方性永久磁石の製造法。[Claims] 1 Finely ground hard ferrite magnetic powder of Ba, Sr, or Pb is subjected to anisotropic granulation treatment by applying a magnetic field to obtain anisotropic granulated powder, and this 32 to 200 mesh Anisotropic granulated powder is filled into a cylindrical molding cavity and compression molded using upper and lower punches. During filling and molding, a radial anisotropic magnetic field with a magnetic field strength of 3000 oersted or less is applied, A method for producing a cylindrical anisotropic permanent magnet, which comprises imparting magnetic anisotropy to a cylindrical compact and then heating and sintering it. 2. A method for producing a cylindrical anisotropic permanent magnet according to claim 1, characterized in that the magnet is molded using anisotropic granulated powder of 48 to 100 meshes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10585980A JPS5731108A (en) | 1980-08-01 | 1980-08-01 | Manufacture of cylindrical anisotropic permanent magnet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10585980A JPS5731108A (en) | 1980-08-01 | 1980-08-01 | Manufacture of cylindrical anisotropic permanent magnet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5731108A JPS5731108A (en) | 1982-02-19 |
| JPH0412010B2 true JPH0412010B2 (en) | 1992-03-03 |
Family
ID=14418703
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10585980A Granted JPS5731108A (en) | 1980-08-01 | 1980-08-01 | Manufacture of cylindrical anisotropic permanent magnet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5731108A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6288312A (en) * | 1985-10-15 | 1987-04-22 | Tohoku Metal Ind Ltd | Forming method for rare earth cobalt magnet in magnetic field |
| JPH01114005A (en) * | 1987-10-28 | 1989-05-02 | Fuji Elelctrochem Co Ltd | Pelletization of permanent magnet powder |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5194406A (en) * | 1975-02-19 | 1976-08-19 | JISEIFUNMATSUSEIKEIPURESUYOKANAGATA | |
| JPS54118467A (en) * | 1978-03-06 | 1979-09-13 | Hitachi Chem Co Ltd | Manufacturing of laminate impregnated with thermosetting synthetic resin |
| JPS55110019A (en) * | 1979-02-16 | 1980-08-25 | Matsushita Electric Ind Co Ltd | Preparation of and apparatus for sinterd magnet |
-
1980
- 1980-08-01 JP JP10585980A patent/JPS5731108A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5731108A (en) | 1982-02-19 |
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