JPH0213452B2 - - Google Patents
Info
- Publication number
- JPH0213452B2 JPH0213452B2 JP59207285A JP20728584A JPH0213452B2 JP H0213452 B2 JPH0213452 B2 JP H0213452B2 JP 59207285 A JP59207285 A JP 59207285A JP 20728584 A JP20728584 A JP 20728584A JP H0213452 B2 JPH0213452 B2 JP H0213452B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- lower punch
- molding
- section
- raw material
- 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)
- Press-Shaping Or Shaping Using Conveyers (AREA)
- Devices For Post-Treatments, Processing, Supply, Discharge, And Other Processes (AREA)
- Powder Metallurgy (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
Description
利用産業分野
この方法は、異方性フエライト磁石の成型装置
に係り、断面弓形の異方性フエライト磁石の両湾
曲面の磁気特性の差を大きくし、外周面側の磁気
特性を大幅に向上させることができる異方性フエ
ライト磁石の成型装置に関する。
背景技術
断面弓形の異方性フエライト磁石を成型する装
置として一般に多用される成型装置は、ダイス内
の成型空間にスラリー状原料粉末を充填し、該原
料粉末を磁界中にて、凹状湾曲面を有する上パン
チと凸状湾曲面を有する下パンチにより圧縮成型
する構成である。
一般に、上記構成の成型装置で異方性フエライ
ト磁石を成型すると、圧縮成型時の水抜き等の影
響あるいは上パンチ側と下パンチ側との成型密度
の差によつて、内周面が強磁性面、外周面が弱磁
性面となり、両周面間で磁気特性に差が生じてい
た。
かかる磁気特性差のある磁石をモーター等に使
用する場合、強磁性面である内周面側を駆動コイ
ルに対向すればよいが、外周面が強磁性であり、
外周側へ磁束を及ぼすことが要求される場合には
全く不適であり、また、近年、各種機器の小形化
並びに特性の向上が強く求められており、弓形磁
石の外周面側のトータル磁束（ΦT）の向上が切
望されている。
しかし、断面弓形の異方性フエライト磁石の両
周面に、磁気特性の強弱を積極的にかつ所望の差
で設ける手段は確立されておらず、特開昭59−
28541号公報に、磁界中圧縮成型時の上下パンチ
磁極面の面積比を変えることにより、偏平板形状
磁石の磁気特性の強弱を制御する方法が提案され
ている程度である。
発明の目的
この発明は、断面弓形の異方性フエライト磁石
の成型装置に係り、断面弓形異方性フエライト磁
石の両周面の磁気特性の差を大きくし、外周面側
の磁気特性を大巾に向上させることができる成型
装置を目的としている。
発明の構成と効果
この発明は、断面弓形の異方性フエライト磁石
の両周面における磁気特性差を設ける手段につい
て種々検討した結果、磁性材からなる下パンチに
断面弓形状の非磁性体を介在させて、圧縮成型す
ると、得られた磁石の両面間の磁気特性差を大き
くでき、外周面の磁気特性を大幅に向上させるこ
とができることを知見したものである。
すなわち、この発明は、
ダイス内の成型空間にスラリー状原料粉末を充
填し、該原料粉末を磁界中にて、凹状湾曲面を有
する上パンチと凸状湾曲面を有する下パンチによ
り圧縮成型する断面弓形の異方性フエライト磁石
の成型装置において、
少なくとも充填した原料粉末との接触面部分の
下パンチの成型空間側表面に、断面弓形状の非磁
性体を設け、
該非磁性体の厚みを非磁性体の外周面円弧中心
点と内周面円弧中心点を偏心させ、中央部を厚く
したことを特徴とする異方性フエライト磁石の成
型装置である。
この発明において、下パンチの磁極面と原料粉
末間に介在させる断面弓形状の非磁性体は、成形
の作業性を考慮すると、予め下パンチの磁極面に
設ける構成が望ましい。また、圧縮成型装置は公
知のいかなる構成のものでも適用できる。
上記非磁性体を下パンチの磁極面に設ける形態
は、磁極面の中心部に成型空間横断面と同寸法、
あるいは下パンチがダイスに当接する場合は、成
型空間よりやや大きい寸法の非磁性体を嵌着する
など、下パンチの成型空間側内周表面において、
少なくとも充填した原料粉末との接触面部分に、
原料粉末が洩れることがないように、断面弓形状
の非磁性体を設ければよく、被成形体の形状、寸
法及び要求される磁気特性を考慮して適宜選定す
るとよい。
下パンチの成型空間側表面に設けた断面弓形状
の非磁性体部分の厚みを、非磁性体の外周面円弧
中心点と内周面円弧中心点を偏心（偏心量Δl）
させ、中央部を厚くすることにより、得られる断
面弓形永久磁石の両周面の磁気特性差を大きくし
て、外周面の磁気特性を大きく向上させるのに極
めて有効である。
さらに、非磁性体の厚みＴは、成型体の形状に
より適宜選定すればよいが、厚すぎると適正な磁
界形成に多くの電流を要して効率上種々の問題を
来たし、また、薄すぎると十分な効果が得られな
くなるが、本発明者は以下に述べる条件が好まし
いことを知見した。
下パンチの磁極面に同寸法の非磁性体を設ける
場合；
Ｔ；５mm〜60mm、
Δl；0.1T〜1.5T
図面に基づく発明の開示
第１図はこの発明による断面弓形状磁石を成型
する成型装置の縦断説明図である。
構 成
成型空間は、非磁性体のダイス１に設けた角柱
状空間内に、磁性材からなり凸状湾曲面を有する
角柱状の下パンチ２を嵌入して形成され、原料粉
末が同空間内に充填される。
また、ダイス１上端面には、凹状湾曲面からな
る角柱状の上パンチ４が当接し、下パンチ２がダ
イス１内に嵌入する。
第１図に示す如く、非磁性体３には、上面寸法
が下パンチ２と同寸法の断面弓形状非磁性体を用
いて、これを下パンチ２に貼着してあり、かつ非
磁性体３の外周面円弧中心点と内周面円弧中心点
を偏心させて中央部を厚くしてある。
さらに、上パンチ４と下パンチ２には図示しな
い油圧シリンダが付設されて上下方向に移動して
加圧する構成となり、上パンチ４と下パンチ２の
外周部には磁界を形成するための電磁コイル５が
設けてある。
作用効果
上記構成の成型装置において、ダイス１内の成
型空間にスラリー状の原料粉末を充填したのち、
電磁コイル５を励磁して磁界を形成し、ダイス
１、上パンチ４を降下させて圧縮成型する。
この際、スラリー状原料粉末の水分は、例えば
上パンチ４に設ける抜水孔より抜水するか、ある
いは上パンチ４と原料粉末との間の濾過布等のフ
イルター類より抜水する。
また、下パンチの磁極面の横断面面積Suと、
ダイス内の成型空間における横断面面積Sdとの
比、Su／Sdは、１以上であれば、この発明の効
果は十分に発揮される。
一方、電磁コイルは、上パンチと下パンチの外
周部に各々設けた場合を説明したが、この場合、
上下コイルの起磁力バランスは、同等、または上
側が強いほうがよい。あるいは起磁力が十分に大
きければ、上パンチのみに周設してもよい。ま
た、ダイスの外周部に電磁コイルを設けてもよ
い。
実施例
前述した第１図のこの発明による成型装置を用
いて、SrO10％、Fe2O388％を含有するスラリー
状原料粉末を、8kOeの磁界中で、0.5t／cm2の圧
力を加え、外径R242mm×内径R136mm×幅70mm×
高さ45mm寸法に成型し、得られた成型体に、1250
℃×１時間の焼結を施し、断面弓形及び断面蒲鉾
型異方性フエライト磁石を得た。
また、下パンチに非磁性体を介在させない以外
は、全く同一条件で成型・焼結した従来装置によ
る異方性フエライト磁石を得た。
得られた各種磁石の残留磁束密度を測定し、強
磁性面（外周面）と弱磁性面（内周面）との比と
して、比較例の当該比を１として対比させた測定
結果（Br比）と、外周面におけるトータル磁束
（ΦT）を比較例と対比させた測定結果を第１表に
示す。
Application industry field This method is related to a molding device for anisotropic ferrite magnets, which increases the difference in magnetic properties between both curved surfaces of an anisotropic ferrite magnet with a bow-shaped cross section, and greatly improves the magnetic properties on the outer peripheral surface side. The present invention relates to a molding device for anisotropic ferrite magnets. BACKGROUND ART A molding device that is commonly used for molding anisotropic ferrite magnets having an arcuate cross section fills a molding space in a die with slurry-like raw material powder, and then molds the raw material powder into a concave curved surface in a magnetic field. Compression molding is performed using an upper punch having a convex curved surface and a lower punch having a convex curved surface. Generally, when an anisotropic ferrite magnet is molded using a molding device with the above configuration, the inner peripheral surface becomes ferromagnetic due to the effects of water removal during compression molding or the difference in molding density between the upper punch side and the lower punch side. The surface and the outer circumferential surface were weakly magnetic, and there was a difference in magnetic properties between the two circumferential surfaces. When a magnet with such a difference in magnetic properties is used in a motor or the like, it is sufficient that the inner peripheral surface side, which is a ferromagnetic surface, faces the drive coil, but the outer peripheral surface is ferromagnetic,
It is completely unsuitable when magnetic flux is required to be applied to the outer circumferential side.In addition, in recent years, there has been a strong demand for miniaturization and improved characteristics of various devices, and the total magnetic flux (Φ There is a strong need for improvement in T ). However, no means has been established to actively provide desired differences in the strength of magnetic properties on both circumferential surfaces of an anisotropic ferrite magnet with an arcuate cross section.
No. 28541 proposes a method of controlling the strength of the magnetic properties of a flat plate magnet by changing the area ratio of the upper and lower punch pole faces during compression molding in a magnetic field. Purpose of the Invention The present invention relates to a molding device for an anisotropic ferrite magnet having an arcuate cross section, which increases the difference in magnetic properties between both circumferential surfaces of an anisotropic ferrite magnet having an arcuate cross section, and greatly improves the magnetic properties on the outer circumferential surface side. The aim is to create a molding device that can improve the Structure and Effects of the Invention As a result of various studies on means for creating a difference in magnetic properties on both circumferential surfaces of an anisotropic ferrite magnet with an arcuate cross section, the present invention has developed a lower punch made of a magnetic material with a non-magnetic material having an arcuate cross section. It has been found that by compression molding the resulting magnet, the difference in magnetic properties between the two sides of the obtained magnet can be increased, and the magnetic properties of the outer circumferential surface can be significantly improved. That is, the present invention has a cross section in which a molding space in a die is filled with slurry-like raw material powder, and the raw material powder is compression-molded in a magnetic field by an upper punch having a concave curved surface and a lower punch having a convex curved surface. In a molding device for a bow-shaped anisotropic ferrite magnet, a non-magnetic material having an arc-shaped cross section is provided on the molding space side surface of the lower punch at least in the contact surface with the filled raw material powder, and the thickness of the non-magnetic material is set to be non-magnetic. This is an anisotropic ferrite magnet molding device characterized in that the center point of the arc on the outer peripheral surface of the body and the center point of the arc on the inner peripheral surface of the body are eccentric, and the center portion is thickened. In the present invention, it is desirable that the non-magnetic material having a bow-shaped cross section to be interposed between the magnetic pole surface of the lower punch and the raw material powder is provided in advance on the magnetic pole surface of the lower punch in consideration of molding workability. Furthermore, any known configuration of the compression molding device can be applied. The form in which the above-mentioned non-magnetic material is provided on the magnetic pole surface of the lower punch is such that the non-magnetic material is provided at the center of the magnetic pole surface with the same size as the cross section of the molding space.
Alternatively, if the lower punch contacts the die, a non-magnetic material with a size slightly larger than the molding space may be fitted on the inner circumferential surface of the lower punch on the molding space side.
At least on the contact surface with the filled raw material powder,
In order to prevent the raw material powder from leaking, a non-magnetic material having an arcuate cross section may be provided, and may be appropriately selected in consideration of the shape and dimensions of the object to be molded and the required magnetic properties. The thickness of the non-magnetic material part with a bow-shaped cross section provided on the molding space side surface of the lower punch is determined by eccentricity between the center point of the arc on the outer peripheral surface and the center point of the arc on the inner peripheral surface of the non-magnetic material (amount of eccentricity Δl)
By making the center part thicker, it is extremely effective to increase the difference in magnetic properties between both circumferential surfaces of the obtained permanent magnet with an arcuate cross section, and to greatly improve the magnetic properties of the outer circumferential surface. Furthermore, the thickness T of the non-magnetic material may be appropriately selected depending on the shape of the molded body, but if it is too thick, a large amount of current is required to form an appropriate magnetic field, causing various problems in terms of efficiency; Although sufficient effects cannot be obtained, the present inventor has found that the conditions described below are preferable. When a non-magnetic material of the same size is provided on the magnetic pole surface of the lower punch; T: 5 mm to 60 mm, Δl: 0.1 T to 1.5 T Disclosure of the invention based on drawings Fig. 1 shows a molding process for forming a magnet with an arcuate cross section according to the present invention. FIG. 2 is a longitudinal cross-sectional view of the device. Configuration The molding space is formed by fitting a prismatic lower punch 2 made of a magnetic material and having a convex curved surface into a prismatic space provided in a non-magnetic die 1, and the raw material powder is is filled with. Further, a prismatic upper punch 4 having a concave curved surface is in contact with the upper end surface of the die 1, and a lower punch 2 is fitted into the die 1. As shown in FIG. 1, the non-magnetic material 3 is a non-magnetic material with an arch-shaped cross section whose upper surface dimension is the same as that of the lower punch 2, and is adhered to the lower punch 2. The center point of the arc on the outer circumferential surface and the center point of the arc on the inner circumferential surface of No. 3 are made eccentric to make the central portion thicker. Furthermore, a hydraulic cylinder (not shown) is attached to the upper punch 4 and the lower punch 2, and is configured to move in the vertical direction to apply pressure, and the outer periphery of the upper punch 4 and the lower punch 2 is equipped with an electromagnetic coil for forming a magnetic field. 5 is provided. Effects In the molding device configured as described above, after filling the molding space in the die 1 with slurry-like raw material powder,
The electromagnetic coil 5 is excited to form a magnetic field, and the die 1 and upper punch 4 are lowered to perform compression molding. At this time, water in the slurry-like raw material powder is drained, for example, through a drainage hole provided in the upper punch 4 or through a filter such as a filter cloth between the upper punch 4 and the raw material powder. In addition, the cross-sectional area Su of the magnetic pole surface of the lower punch,
When the ratio of the cross-sectional area Sd of the molding space in the die to the cross-sectional area Sd is 1 or more, the effects of the present invention are fully exhibited. On the other hand, we have explained the case where the electromagnetic coils are provided on the outer periphery of the upper punch and the lower punch, respectively, but in this case,
The magnetomotive force balance between the upper and lower coils should be equal or stronger on the upper side. Alternatively, if the magnetomotive force is sufficiently large, it may be provided around only the upper punch. Further, an electromagnetic coil may be provided on the outer periphery of the die. Example Using the molding apparatus according to the present invention shown in FIG . , outer diameter R 2 42mm x inner diameter R 1 36mm x width 70mm
The molded body was molded to a height of 45 mm, and 1250
Sintering was performed for 1 hour at ℃ to obtain anisotropic ferrite magnets having an arcuate cross section and a semi-cylindrical cross section. In addition, an anisotropic ferrite magnet was obtained using a conventional apparatus that was molded and sintered under exactly the same conditions except that no nonmagnetic material was interposed in the lower punch. The residual magnetic flux density of the various magnets obtained was measured, and the ratio of the ferromagnetic surface (outer surface) to the weakly magnetic surface (inner surface) was compared with the ratio of the comparative example as 1 (Br ratio ) and the total magnetic flux (Φ T ) on the outer circumferential surface compared with the comparative example. Table 1 shows the measurement results.
【表】
第１表から明らかなように、この発明装置によ
ると、断面弓形異方性フエライト磁石の両周面の
磁気特性の差は大きくなり、外周面側の磁気特性
を大幅に向上することが分る。[Table] As is clear from Table 1, according to the device of the present invention, the difference in magnetic properties between both circumferential surfaces of a ferrite magnet with arcuate cross-sectional anisotropy becomes large, and the magnetic properties on the outer circumferential surface side are significantly improved. I understand.
第１図はこの発明による断面弓形状磁石を成型
する成型装置の縦断説明図である。
１……ダイス、２……下パンチ、３……非磁性
体、４……上パンチ、５……電磁コイル。
FIG. 1 is a longitudinal sectional view of a molding apparatus for molding a magnet having an arcuate cross section according to the present invention. 1... Dice, 2... Lower punch, 3... Non-magnetic material, 4... Upper punch, 5... Electromagnetic coil.
Claims (1)
充填し、該原料粉末を磁界中にて、凹状湾曲面を
有する上パンチと凸状湾曲面を有する下パンチに
より圧縮成型する断面弓形の異方性フエライト磁
石の成型装置において、少なくとも充填した原料
粉末との接触面部分の下パンチの成型空間側表面
に、断面弓形状の非磁性体を設け、該非磁性体の
厚みを非磁性体の外周面円弧中心点と内周面円弧
中心点を偏心させ、中央部を厚くしたことを特徴
とする異方性フエライト磁石の成型装置。1 Anisotropy with an arcuate cross section by filling a molding space in a die with slurry-like raw material powder and compressing the raw material powder in a magnetic field with an upper punch having a concave curved surface and a lower punch having a convex curved surface. In a ferrite magnet molding device, a non-magnetic material having an arcuate cross section is provided on the molding space side surface of the lower punch at least in the contact surface with the filled raw material powder, and the thickness of the non-magnetic material is equal to the arc of the outer peripheral surface of the non-magnetic material. A molding device for an anisotropic ferrite magnet characterized by making the center point and the center point of the inner circumferential arc eccentric, and making the center part thicker.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20728584A JPS6184806A (en) | 1984-10-02 | 1984-10-02 | Molding device of anisotropic ferrite magnet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20728584A JPS6184806A (en) | 1984-10-02 | 1984-10-02 | Molding device of anisotropic ferrite magnet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6184806A JPS6184806A (en) | 1986-04-30 |
| JPH0213452B2 true JPH0213452B2 (en) | 1990-04-04 |
Family
ID=16537260
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20728584A Granted JPS6184806A (en) | 1984-10-02 | 1984-10-02 | Molding device of anisotropic ferrite magnet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6184806A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4995430B2 (en) * | 2005-03-30 | 2012-08-08 | Ｔｄｋ株式会社 | Manufacturing method of tile-like rare earth sintered magnet |
| JP5120534B2 (en) * | 2006-03-15 | 2013-01-16 | Ｔｄｋ株式会社 | Anisotropic ferrite magnet and motor |
| CN109514706A (en) * | 2018-11-27 | 2019-03-26 | 闫溪 | A kind of permanent-magnet ferrite mold Optimize magnetic circult structure |
| CN110815509A (en) * | 2019-11-20 | 2020-02-21 | 中钢天源(马鞍山)通力磁材有限公司 | Wet-type hydraulic blank taking system capable of realizing protection demolding |
| CN110919822A (en) * | 2019-12-12 | 2020-03-27 | 湖南航天磁电有限责任公司 | Permanent magnetic ferrite wet process shaping's lower punching die |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5147843Y2 (en) * | 1972-06-23 | 1976-11-18 |
-
1984
- 1984-10-02 JP JP20728584A patent/JPS6184806A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6184806A (en) | 1986-04-30 |
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