JPH0563003B2 - - Google Patents
Info
- Publication number
- JPH0563003B2 JPH0563003B2 JP26500586A JP26500586A JPH0563003B2 JP H0563003 B2 JPH0563003 B2 JP H0563003B2 JP 26500586 A JP26500586 A JP 26500586A JP 26500586 A JP26500586 A JP 26500586A JP H0563003 B2 JPH0563003 B2 JP H0563003B2
- Authority
- JP
- Japan
- Prior art keywords
- green sheet
- sheet
- cylindrical
- ferrite magnet
- rolled
- 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
- 229910000859 α-Fe Inorganic materials 0.000 claims description 14
- 238000005245 sintering Methods 0.000 description 12
- 239000000463 material Substances 0.000 description 5
- 239000011230 binding agent Substances 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000013078 crystal Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 239000002202 Polyethylene glycol Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229920002037 poly(vinyl butyral) polymer Polymers 0.000 description 2
- 229920001223 polyethylene glycol Polymers 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- NUONTTMMRCYJMI-UHFFFAOYSA-N 3,4-dibutylphthalic acid Chemical compound CCCCC1=CC=C(C(O)=O)C(C(O)=O)=C1CCCC NUONTTMMRCYJMI-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 235000019441 ethanol Nutrition 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
Landscapes
- Manufacturing Cores, Coils, And Magnets (AREA)
Description
【発明の詳細な説明】
（産業上の技術分野）
本発明はラジアル異方性円筒状フエライトマグ
ネツトに関する。DETAILED DESCRIPTION OF THE INVENTION (Industrial Technical Field) The present invention relates to a radially anisotropic cylindrical ferrite magnet.
（従来の技術）
ラジアル異方性の円筒状フエライトマグネツト
は、従来、材料をロール圧延してシート状とな
し、このシート状材料を加圧しながら渦巻き状に
密着して巻き付けて円筒状とし、しかるのち燒結
して作製したものが知られている（特公昭56−
10768号公報）。(Prior art) A radially anisotropic cylindrical ferrite magnet has conventionally been produced by roll-rolling a material into a sheet, and then tightly wrapping this sheet-like material in a spiral shape while applying pressure to form a cylindrical shape. It is known that the product was produced by sintering after that time (Special Publication Act 1983-).
10768).
（発明が解決しようとする問題点）
しかし、この円筒状フエライトマグネツトは燒
結時収縮量及び熱膨張係数の異方性のため燒結時
に割れを発生し易く、製造上の歩留まりが悪い。
本発明はかかる事情に鑑みてなされたものであつ
て、製造が容易で、製造上の歩留まりも良い新規
なラジアル異方性円筒状フエライトマグネツトの
提供を目的とする。(Problems to be Solved by the Invention) However, this cylindrical ferrite magnet tends to crack during sintering due to the amount of shrinkage during sintering and the anisotropy of the coefficient of thermal expansion, resulting in poor manufacturing yield.
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a novel radially anisotropic cylindrical ferrite magnet that is easy to manufacture and has a good manufacturing yield.
（問題点を解決するための手段）
以下、本発明を説明する。本発明のラジアル異
方性円筒状フエライトマグネツトは、シート面に
直交する方向に磁気異方性を有する１枚以上のグ
リーンシート１個の円筒状に丸め、各グリーンシ
ートの端部を接合させることなく互いに当接させ
るか、もしくは細隙を隔して近接せしめ、この状
態で燒結してなる。(Means for solving the problems) The present invention will be described below. The radially anisotropic cylindrical ferrite magnet of the present invention consists of one or more green sheets having magnetic anisotropy in a direction perpendicular to the sheet surface, rolled into a cylindrical shape, and the ends of each green sheet joined together. Either they are brought into contact with each other without any gaps between them, or they are brought close to each other with a gap between them, and then sintered in this state.
グリーンシートは周知のごとくバインダーとセ
ラミツクを混合してシート状としたものであるが
本発明のラジアル異方性円筒状フエライトマグネ
ツトの材料としての、グリーンシートはシート面
に直交する方向に磁気異方性を有する。このよう
なグリーンシートは以下の如くして作製すること
が出来る。 As is well known, a green sheet is made into a sheet by mixing a binder and ceramic, but the green sheet used as a material for the radially anisotropic cylindrical ferrite magnet of the present invention has magnetic anisotropy in the direction perpendicular to the sheet surface. It has directionality. Such a green sheet can be produced as follows.
即ち、ｎ＝4.5〜6.2としてBaO・nFe2O3または
SrO.nFe2O3で示される、結晶異方性を有するフ
エライト磁石粉末に、バインダーとして例えば
PVB（ポリビニール・ブチラール）、可塑剤とし
て例えばDBP（ジブチルフタル酸）及びPEG（ポ
リエチレン・グリコール）等を配合し、更に溶剤
としてエチルアルコール等を加えて混練し、これ
を圧延ロールにて圧延率40％前後で数回繰り返し
て圧延し、シート面に直交する方向に磁気異方性
を持つように結晶配向をもつた、厚さ１〜３mm程
度のグリーンシートとするのである。 That is, BaO・nFe 2 O 3 or
For example, as a binder, ferrite magnet powder with crystal anisotropy represented by SrO.nFe 2 O 3 is added.
PVB (polyvinyl butyral), plasticizers such as DBP (dibutylphthalic acid) and PEG (polyethylene glycol) are mixed, and ethyl alcohol is added as a solvent and kneaded. The green sheet is repeatedly rolled several times at around 40% to form a green sheet with a thickness of about 1 to 3 mm, with crystal orientation so as to have magnetic anisotropy in the direction perpendicular to the sheet surface.
グリーンシートは、１枚以上が１個の円筒状に
丸められる。２枚以上を丸めるときは、互いに重
ねて丸めればよい。丸められた各グリーンシート
の端部はこれを相互に接合させることなく互いに
当接させるか、もしくは細隙を隔して近接せしめ
る。そして、この状態で燒結する。 One or more green sheets are rolled into a cylindrical shape. If you want to roll two or more pieces, just roll them one on top of the other. The ends of each rolled green sheet are brought into contact with each other without being joined together, or are brought close to each other with a gap in between. Then, it is sintered in this state.
（実施例） 以下、具体的な実施例につき説明する。(Example) Hereinafter, specific examples will be described.
第３図において、符号Ｓは、シート面に直交す
る方向、即ち、第３図の上下方向に磁気異方性
を持つたグリーンシートを示している。このグリ
ーンシートＳは第２図に示すように長方形形状
である。グリーンシートＳを円筒状に丸めるに
は、以下のようにカーリング成形すればよい。グ
リーンシートＳを半円形の断面形状を有する下型
２０のうえに置いて、円柱状の芯金２２で押圧
し、グリーンシートＳを下型の形状にならつて変
形させる（第３図，）。なお第３図には、
グリーンシートＳの長辺が現れている。 In FIG. 3, the symbol S indicates a green sheet having magnetic anisotropy in the direction perpendicular to the sheet surface, that is, in the vertical direction in FIG. This green sheet S has a rectangular shape as shown in FIG. In order to curl the green sheet S into a cylindrical shape, curling may be performed as follows. The green sheet S is placed on a lower mold 20 having a semicircular cross-sectional shape, and is pressed with a cylindrical core bar 22 to deform the green sheet S to follow the shape of the lower mold (FIG. 3). Furthermore, in Figure 3,
The long side of the green sheet S is exposed.
次いで、第３図，に示すように半円形の断
面形状を有する上型２４を用いてグリーンシート
Ｓを芯金２２の周面に巻き付けて円筒状にする。
その際、グリーンシートＳの両端部Ｐ，Ｑを接合
して一体とせずに、互いに軽く当接させるか、或
は、第３図に示す如く、細〓SLを隔して互い
に近接せしめる。 Next, as shown in FIG. 3, the green sheet S is wound around the circumferential surface of the core metal 22 using an upper mold 24 having a semicircular cross-sectional shape to form a cylindrical shape.
At this time, the ends P and Q of the green sheet S are not joined and integrated, but are brought into slight contact with each other, or, as shown in FIG. 3, are brought close to each other with a narrow distance SL between them.
このようにして、円筒状に丸めたグリーンシー
トＳを、次いで、第３図に示すように円筒状の
治具２６に挿入する。なお、細〓SLの大きさは
シート厚、円筒形状の直径、バインダーの配合成
分により、異なつたものとなるが、一般的に０
（軽く当接させる場合）ないし数mmに設定する。
また、上記のカーリング成形に於いて、大きな形
成力や高い成形精度は必要でなく、第３図に示
すように円筒状の治具２６に挿入出来ればよい。
この挿入は、丸められたグリーンシートＳの有す
る若干の弾性と際隙SLを利用することにより簡
単に行う事ができる。さらに、治具２６への挿入
後のグリーンシートＳの真円度が悪い場合は、第
４図に示すように、円柱状の芯棒２８を転動させ
てグリーンシートＳを内側から治具２６に向かつ
て押圧することにより治具の形状に密着整形すれ
ばよい。 The green sheet S rolled into a cylindrical shape in this manner is then inserted into a cylindrical jig 26 as shown in FIG. Note that the size of the thin SL will vary depending on the sheet thickness, the diameter of the cylindrical shape, and the binder composition, but it is generally 0.
(for light contact) or set to several mm.
Further, in the above-mentioned curling forming, a large forming force and high forming accuracy are not required, and it is sufficient that the material can be inserted into a cylindrical jig 26 as shown in FIG.
This insertion can be easily performed by utilizing the slight elasticity of the rolled green sheet S and the gaps SL. Furthermore, if the roundness of the green sheet S after being inserted into the jig 26 is poor, as shown in FIG. What is necessary is just to shape it closely to the shape of the jig by pressing it towards the jig.
その後、治具２６に挿入したままの状態で300
℃程度の低温で24時間以上加熱して、バインダー
や溶剤を蒸発させて乾燥し、しかるのち円筒状の
グリーンシートＳを治具２６から抜き取り、約
1200℃の高温で燒結する。 After that, while it was inserted into the jig 26,
The binder and solvent are evaporated and dried by heating at a low temperature of about °C for more than 24 hours, and then the cylindrical green sheet S is pulled out from the jig 26 and is
Sinter at a high temperature of 1200℃.
かくして、第１図に示す如きラジアル異方性円
筒状フエライトマグネツト１０が得られる。燒結
前に形成されていた細〓は、スリツト１２とな
る。 In this way, a radially anisotropic cylindrical ferrite magnet 10 as shown in FIG. 1 is obtained. The narrow strip formed before sintering becomes the slit 12.
上記実施例では、第２図に示すような、長方
形形状のグリーンシートＳを丸めたが、グリーン
シートの形状は円筒状に丸められれば、何でもよ
く、正方形形状でもよいし、第２図，に示す
ような、平行四辺形形状のグリーンシートＳ１
や、曲線の縁部をもつグリーンシートＳ２でもよ
い。なお、第２図に示した３種のグリーンシート
の丸めの方向は、図の左右方向である。 In the above embodiment, a rectangular green sheet S as shown in FIG. A parallelogram-shaped green sheet S1 as shown
Alternatively, a green sheet S2 having a curved edge may be used. Note that the direction in which the three types of green sheets shown in FIG. 2 are rolled is the left-right direction in the figure.
また、２枚以上のグリーンシートを重ねて１個
の円筒状に丸める場合には、円筒状の治具に挿入
後、第４図に即して説明したように芯棒２８を転
動することにより、シート間の密着性を高めシー
ト間の空気を排出することができる。 Furthermore, when stacking two or more green sheets and rolling them into one cylindrical shape, after inserting them into a cylindrical jig, roll the core rod 28 as explained in accordance with FIG. 4. This makes it possible to improve the adhesion between the sheets and to discharge air between the sheets.
（発明の作用・効果）
本発明のラジアル異方性円筒状フエライトマグ
ネツトは、上記の如く作製されるので、燒結の際
に割れが発生しにくい。以下、この理由を簡単に
説明する。グリーンシートを円筒状にまるめ、シ
ート両端を接合して第５図に示すように円筒３０
にすると、図にようにＲ方向、Ｃ方向を考える
と、磁気異方性の要因となる結晶配向性のため
に、燒結収縮量の大きさ、熱膨張係数の大きさと
もにＲ方向＞Ｃ方向であり、このため、燒結した
のち燒結温度から常温に冷却する際に、結果的に
外周側では圧縮応力、内周側では引張応力が発生
し、これら応力のために割れが発生しやすい。即
ち、第６図に示すように円筒３０の部分３１，
３２，３３を考えて見ると、燒結後の冷却の際に
各部分３１，３２，３３は、これらが単独である
とすると、第６図に符号３１０，３２０，３３
０でように収縮する。このように収縮した部分３
１０，３２０，３３０を繋ぎ合わせてみると、第
６図に示すようになつて、滑らかにつながらな
い。円筒３０では、各部分３１，３２，３３は、
互いに連結されて、互いに変形に対する抵抗とし
て作用し合うが、この抵抗が変形に対して抗しき
れなくなると割れが発生するのである。(Operations and Effects of the Invention) Since the radially anisotropic cylindrical ferrite magnet of the present invention is produced as described above, cracks are less likely to occur during sintering. The reason for this will be briefly explained below. Roll the green sheet into a cylindrical shape and join both ends of the sheet to form a cylinder 30 as shown in Figure 5.
Then, considering the R direction and C direction as shown in the figure, due to the crystal orientation which is a factor of magnetic anisotropy, both the magnitude of sintering shrinkage and the magnitude of the thermal expansion coefficient are R direction > C direction. Therefore, after sintering, when the material is cooled from the sintering temperature to room temperature, compressive stress is generated on the outer circumferential side and tensile stress is generated on the inner circumferential side, and cracks are likely to occur due to these stresses. That is, as shown in FIG.
32 and 33, each part 31, 32, and 33, if they were alone, would be replaced by the numbers 310, 320, and 33 in FIG. 6 during cooling after sintering.
It contracts like this at 0. Part 3 that shrunk like this
If you try to connect numbers 10, 320, and 330, it will not connect smoothly as shown in Figure 6. In the cylinder 30, each portion 31, 32, 33 is
They are connected to each other and act as resistance against deformation, but when this resistance can no longer resist deformation, cracks occur.
しかるに、本発明のラジアル異方性円筒状フエ
ライトマグネツトは燒結されるグリーンシートが
円筒状に丸められても、シートの両端が接合され
ず、軽く当接するか、あるいは細〓を隔して近接
するので、この部分が変形を容易にし、割れの発
生が押さえられるのである。また、グリーンシー
トは丸められると、外周は疎、内周は密となる
が、燒結時には、これらの疎密が均一化するよう
に作用するので内周側は、密が疎になるように変
化し、曲率の縮小を防いで、上記引張応力を緩和
する。特に、複数枚のグリーンシートを１個の円
筒状に丸める場合は上記引張応力を緩和する効果
がシート毎に作用するので、厚肉小径のラジアル
異方性円筒状フエライトマグネツトを容易に実現
できる。 However, in the radially anisotropic cylindrical ferrite magnet of the present invention, even if the green sheet to be sintered is rolled into a cylindrical shape, the two ends of the sheet are not joined, but either lightly touch each other, or are close to each other with a narrow gap between them. Therefore, this part facilitates deformation and prevents the occurrence of cracks. Also, when a green sheet is rolled up, the outer periphery becomes sparse and the inner periphery becomes dense, but during sintering, these densities become uniform, so the inner periphery becomes less dense. , preventing the reduction of curvature and relieving the above tensile stress. In particular, when rolling multiple green sheets into a single cylindrical shape, the above-mentioned tensile stress relieving effect acts on each sheet, making it easy to realize a thick-walled, small-diameter radially anisotropic cylindrical ferrite magnet. .
なお、丸めたグリーンシートを治具に挿入した
後、燒結前に１〜数日間放置すると、この間に、
若干の塑性流動と応力緩和が生ずる。従つて、こ
のような放置工程を行うことにより、燒結時の割
れの発生をさらに有効に防止する事が可能であ
る。 In addition, if you insert the rolled green sheet into the jig and leave it for one to several days before sintering, during this time,
Some plastic flow and stress relaxation occurs. Therefore, by performing such a standing step, it is possible to more effectively prevent the occurrence of cracks during sintering.
第１図は本発明の１実施例を示す斜視図、第２
図はグリーンシートの形状の３例を示す図、第３
図および第４図は本発明のラジアル異方性円筒状
フエライトマグネツトの製造工程を説明するため
の図、第５図および第６図は、本発明の作用・効
果を説明するための図である。
１０……ラジアル異方性円筒状フエライトマグ
ネツト、１２……スリツト、Ｓ，Ｓ１，Ｓ２……
グリーンシート、Ｐ，Ｑ……グリーンシートの端
部、２０……下型、２２……芯金、２４……上
型、２６……治具。
Fig. 1 is a perspective view showing one embodiment of the present invention, Fig. 2 is a perspective view showing one embodiment of the present invention;
The figure shows three examples of green sheet shapes.
4 and 4 are diagrams for explaining the manufacturing process of the radially anisotropic cylindrical ferrite magnet of the present invention, and FIGS. 5 and 6 are diagrams for explaining the action and effect of the present invention. be. 10... Radial anisotropic cylindrical ferrite magnet, 12... Slit, S, S1, S2...
Green sheet, P, Q... end of green sheet, 20... lower die, 22... core bar, 24... upper die, 26... jig.
Claims (1)
る１枚以上のグリーンシートを１個の円筒状に丸
め、各グリーンシートの端部を接合させることな
く互いに当接させるか、もしくは細隙を隔して近
接せしめ、この状態で焼結してなる、ラジアル異
方性円筒状フエライトマグネツト。1. One or more green sheets having magnetic anisotropy in the direction perpendicular to the sheet surface are rolled into a cylindrical shape, and the ends of each green sheet are brought into contact with each other without joining, or the ends of the green sheets are made to contact each other without joining, or by cutting a gap. A radially anisotropic cylindrical ferrite magnet that is separated and placed close to each other and sintered in this state.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26500586A JPS63119508A (en) | 1986-11-07 | 1986-11-07 | Radial anisotropic cylindrical ferrite magnet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26500586A JPS63119508A (en) | 1986-11-07 | 1986-11-07 | Radial anisotropic cylindrical ferrite magnet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63119508A JPS63119508A (en) | 1988-05-24 |
| JPH0563003B2 true JPH0563003B2 (en) | 1993-09-09 |
Family
ID=17411246
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26500586A Granted JPS63119508A (en) | 1986-11-07 | 1986-11-07 | Radial anisotropic cylindrical ferrite magnet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63119508A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63260120A (en) * | 1987-04-17 | 1988-10-27 | Fuji Elelctrochem Co Ltd | Metal mold for anisotropic ferrite magnet |
| JPH071742B2 (en) * | 1987-05-02 | 1995-01-11 | 富士電気化学株式会社 | Anisotropic ferrite magnet molding |
| US20170170695A1 (en) * | 2014-02-12 | 2017-06-15 | Nitto Denko Corporation | Ring magnet for spm motor, production method for ring magnet for spm motor, spm motor, and production method for spm motor |
| JPWO2015121916A1 (en) * | 2014-02-12 | 2017-03-30 | 日東電工株式会社 | Permanent magnet, method for manufacturing permanent magnet, SPM motor, and method for manufacturing SPM motor |
-
1986
- 1986-11-07 JP JP26500586A patent/JPS63119508A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63119508A (en) | 1988-05-24 |
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