JP4057092B2 - Dry magnetic field molding equipment for arc-shaped ferrite magnets - Google Patents

Dry magnetic field molding equipment for arc-shaped ferrite magnets Download PDF

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JP4057092B2
JP4057092B2 JP07017397A JP7017397A JP4057092B2 JP 4057092 B2 JP4057092 B2 JP 4057092B2 JP 07017397 A JP07017397 A JP 07017397A JP 7017397 A JP7017397 A JP 7017397A JP 4057092 B2 JP4057092 B2 JP 4057092B2
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arc
molding
magnetic field
punch
upper punch
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JPH10270276A (en
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光昭 佐々木
淳二 中野
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TDK Corp
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TDK Corp
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    • 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

Description

【０００１】
【発明の属する技術分野】
本発明は径方向の異方性が均一で表面磁束密度分布が一定な円弧状フェライト磁石を低コストで生産性よく製造できる乾式磁場成型装置に関する。
【０００２】
【従来の技術】
家電製品や自動車の電装用などに用いられるモータには高性能、かつ小型、軽量であることが求められている。これらモータには異方性円弧状フェライト磁石や異方性リング状フェライト磁石が用いられており、磁石は径方向が磁化容易軸となるように異方性化されている。これらフェライト磁石は、内周面側の表面磁束密度が強くなるよう径方向に均一に異方性化され、内周面側の表面磁束密度が周方向において一定であることが要求される。
【０００３】
このような異方性円弧状フェライト磁石の製造方法は湿式成型法又は乾式成型法に大別される。
【０００４】
湿式成型法は磁石の配向性が良好であり高特性のものが得られるが、分散媒を排除しながらの成型となるために生産性が低くなり、また金型構造が複雑となり装置も大がかりになるため、製造コストがかなり高くなる。
【０００５】
一方、乾式成型法は磁石の配向性については湿式法に劣るが、生産性が高く装置の構成も単純なのでコストが低くて済む。中でも、上部パンチが型枠の成型空間内に進入して上部パンチのみ、若しくは上部下部両パンチにて加圧が行われる成型方法は、上部パンチと型枠が面で接することがなく金型寿命が長くかつ生産性も高い。また、金型構造も単純で小型で済むため、高生産性含め製造コストが非常に低い。
【０００６】
【発明が解決しようとする課題】
しかしながら、前記の乾式成型方法を用いる場合は、一般に円弧状フェライト磁石の外周側の上下に関係なく、上部パンチと下部パンチは両方とも磁性体が用いられているため、磁束線が外周側の磁性体パンチにも集束するので径方向に均一に配向させることは不可能である。また、一部ステライト等の非磁性体部を設ける程度で配向を制御しているが、本来求められる配向とは大きくかけ離れたものである。
【０００７】
このような配向の均一化を図るために、特開平５-２３９５０５号公報には、所要口径のダイス内にあって、表面にステライトを溶着した磁性体の下側金型と磁性体の上側金型とから成る磁場プレス金型において、下側金型の幅に対して上側金型の幅を所要分広幅にした金型について記載されている。しかし、型枠の成型空間内（同公報では「ダイス内」）に上部パンチ（同公報では「上側金型」）が進入しないで成型が行われる方法であるため、金型も大がかりとなり生産性も低くなるため、湿式成型法との優位性がなくなってしまい、低コスト、高生産性は期待できない。
【０００８】
そこで、本発明は生産性良く低コストで、径方向の異方性が均一で表面磁束密度分布が一定である円弧状フェライト磁石を製造する乾式磁場成型装置を提供するものである。
【０００９】
【課題を解決するための手段】
このような目的は下記（１）又は（２）の構成により達成できる。
【００１０】
（１）型枠と上部パンチと下部パンチと有し、前記上部パンチが前記型枠と前記下部パンチから構成される成型空間に進入して成型が為される円弧状フェライト磁石の乾式磁場成型装置において、上部パンチは円弧状フェライト磁石の外周側を形成し、かつ、非磁性体からなり、下部パンチは円弧状フェライト磁石の内周側を形成し、かつ、その成型面に非磁性体を設けた磁性体からなることを特徴とする円弧状フェライト磁石の乾式磁場成型装置。
【００１１】
（２）前記乾式磁場成型装置において、前記上部パンチの上方に上部パンチの成型面の円弧形状に沿った形状の下面を有し、かつ、前記下面の面積が前記上部パンチの成型面の面積より大きい磁性体治具を装着してなることを特徴とする（１）に記載の乾式磁場成型装置。
【００１２】
【発明の実施の形態】
図１及び図２を参照しながら本発明に係る乾式磁場成型装置について具体的に説明する。
【００１３】
図１に本発明に係る乾式磁場成型装置の一例であって、その要部（成型部付近）断面図を示す。即ち、本発明に係る乾式磁場成型装置は、型枠１、上部パンチ２、下部パンチ３、型枠１と下部パンチ３から構成される成型空間４、コイル５及び上部パンチ２、下部パンチ３の成型空間側に設けられたステライト部６を有する。
【００１４】
そして、上部パンチ２は円弧状フェライト磁石の外周面を形成し（よって、円弧状フェライト磁石の外周面を形成する当該パンチの面の形状はその断面から見て凹状である（以下、外周成型面２ａとする））、非磁性体からなり、下部パンチ３は円弧状フェライト磁石の内周面を形成し（よって、円弧状フェライト磁石の内周面を形成する当該パンチの面の形状はその断面から見て凸状である（以下、内周成型面３ａとする））、内周成型面３ａに非磁性体を設けた磁性体（同図中の斜線部）からなる。上部パンチを非磁性体とすることで、磁界印加時の成型空間内の磁界方向は下部パンチから放散することになる。つまり、円弧状フェライト磁石の配向が外周面に集束したり、部分的な配向方向の偏り等が起こらず、径方向に均一に異方性化することができる。
【００１５】
ただし、上部パンチを非磁性体とすると上下パンチ間の磁界強度が劣化するため、上部パンチを磁性体とするときよりも高めにする必要があるが、成型体の面積、厚さ等により必要磁界が異なるため、印加磁界は成型体に応じて都度適宜選択すればよい。
【００１６】
また、上部パンチを構成する非磁性体の材質は特に限定されず、例えば、ステンレス鋼、銅ベリリウム合金、ハイマンガン鋼、青銅、真鍮、非磁性超鋼等を用いることができ、２種以上の材質を組み合わせても良い。例えば、図１に示すように上部パンチ２の成型面に耐磨耗性の向上及び配向の制御のためにステライト部６を設けるが如きである。
【００１７】
一方、下部パンチを構成する磁性体の材質は特に限定されず、一般に用いられるものであればよく、例えば炭素鋼、炭素工具鋼、合金工具鋼、ダイス鋼等が用いられる。また、円弧状フェライト磁石の内周面を形成するパンチの成型面には耐磨耗性の向上及び配向の制御のためにステライト部を設けることが一般的である。よって、当該下部パンチ３にもステライト部６が設けられる。ここで、ステライト以外にも非磁性で耐磨耗性材料であれば何でもよいが、例えば非磁性超鋼等を用いることができる。
【００１８】
型枠１の材質は非磁性体であればよく、上部パンチと同様の材質を用いることができる。また、当該型枠の成型空間内壁面にも非磁性超鋼、ステライト等の耐磨耗材が設けられる。
【００１９】
更に、本発明に係る乾式磁場成型装置は、型枠１と下部パンチ３から構成される成型空間４に上記パンチが進入することにより成型が行われる（図１参照）。
【００２０】
詳しくは、成型空間４とは、型枠１のシリンダ部１ａの空間のうち内嵌した下部パンチ３が占める部分を除いた空間である。そして、当該成型空間４へ成型される粉末が充填され、上部パンチ２が当該成型空間４に進入する形で成型されるものである。
【００２１】
また、上部パンチ２及び下部パンチ３の幅は同一であり、これらの幅は前記シリンダ部１ａの内径と同一幅（但し、同一幅といっても、当然にパンチが上下できる程度のマージンは備え、シリンダ部１ａの上部にはテーパーを設けてもよい）である。よって、上部パンチ２の成型空間への進入量は型枠１によっては規制されることがない。換言すれば、上部パンチ又は型枠に段差を設けて上部パンチと型枠を面で接することにより上下動を規制していないので金型寿命が長くかつ生産性も高い。また、金型構造も単純で小型で済むため、円弧状フェライト磁石の高生産性含め製造コストが非常に低い。
【００２２】
また、図２に示すように、本発明に係る乾式磁場成型装置は上部パンチ２の上方に上部パンチの成型面２ａの円弧に沿った形状の下面７ａを有する磁性体治具７を装着することが好ましい。非磁性体からなる上部パンチ側に磁性体治具７を設けることで、成型空間内の磁界強度が高まり、かつ磁性体治具７の下面７ａの形状を上部パンチの成型面に沿った構成とすることで、完全な径方向の配向が可能となるからである。この磁性体治具７の下面７ａの面積は、円弧状フェライト磁石の端部配向に偏りを与えない程度に大きめにすればよい。また、材質としては通常の磁性体であればよく、例えば炭素鋼、炭素工具鋼、合金工具鋼、ダイス鋼等が用いられる。
【００２３】
続いて、本発明に係る乾式磁場成型装置の成型部以外の構成について説明する。
【００２４】
通常、磁場成型装置の枠組みは磁性体で構成されており、磁界印加時に閉磁路を形成できる機構になっている。本発明の成型装置本体も磁性体で構成されており、上部パンチ２及び下部パンチ３の装着部（図示せず）は磁性体である。つまり、上部パンチを非磁性体とするが上部パンチ装着部は磁性体のため、成型装置全体では磁界印加時、閉磁路を形成することができる。ここで、磁性体の材質としては前記磁性体と同様に通常の磁性体であればよく、例えば炭素鋼、炭素工具鋼、合金工具鋼、ダイス鋼等が用いられる。
【００２５】
【実施例】
以下、本発明の具体的実施例を示す。
【００２６】
＜実施例１＞
図１に示される乾式成型装置を用いて、ストロンチウムフェライトの材料粉末を磁場中で成型した。ここで、非磁性体の上部パンチ２はステンレス鋼のＳＵＳ３０４からなり、磁性体の下部パンチ３は合金工具鋼のＳＫＳ２からなり、共に成型面２ａ、３ａにはステライト部６を溶着したものを用いた。得られた成型体を１２４０℃で焼成し表面加工を加えた後に円弧状フェライト磁石（試料Ｎｏ．１）を得た。続いて、フラックスメータによりトータルフラックス及びガウスメータにより表面磁束波形の測定を行った。
【００２７】
それぞれの結果について表１及び図３に示す。ここで、表１における向上率とは、下記試料Ｎｏ．３に対するトータルフラックスの向上率を意味する。
【００２８】
なお、比較のために図４に示すように上部パンチ２０が磁性体からなり、下部パンチ３０が成型面に非磁性体であるステライト部６０を設けた磁性体からなり、上部パンチ２０及び下部パンチ３０が型枠１０に内嵌することにより成型が行われる、従来の乾式成型装置にて磁場中で成型した。また、図４に示す乾式成型装置において上部パンチ２０の成型面にも配向制御のためにステライトを溶着したものも用いて同様に成型した。ここで、使用した上部パンチ２０及び下部パンチ３０の磁性体の材料はＳＫＳ２である。得られた成型体を前記と同様に処理（それぞれ、試料Ｎｏ．３、試料Ｎｏ．４）し、トータルフラックス及び表面磁束波形を測定した。
【００２９】
【表１】

Figure 0004057092
【００３０】
表１及び図３から本発明の効果は明らかである。即ち、本発明に係る乾式磁場成型装置により作成した円弧状フェライト磁石は、磁性体からなる上部パンチにより作成した試料Ｎｏ．３だけでなく、これに配向制御のためにステライトを溶着し作成した試料Ｎｏ．４と比較しても３．３％もトータルフラックスが向上している（表１参照）。また、図３に示す表面磁束波形を見ると、特に円弧状フェライト磁石の内周側の端部の磁束密度が向上しており、径方向に均一に異方性化されていることがわかる。
【００３１】
＜実施例２＞
図２に示される成型装置、即ち、上部パンチ２の上方に磁性体治具７を装着した他は実施例１と同様の操作を行い、得られた試料（試料Ｎｏ．２）のトータルフラックス及び表面磁束波形の測定を行った。なお、用いた磁性体治具７の下面７ａは成型完了直前に上部パンチ２が位置したときに、上部パンチ２の成型面２ａの円弧と同心円になるような形状とした。
【００３２】
その結果を表１及び図３に示す。
【００３３】
表１及び図３から本発明の効果は明らかである。即ち、磁性体からなる上部パンチにより作成した試料Ｎｏ．３だけでなく、これに配向制御のためにステライトを溶着し作成した試料Ｎｏ．４と比較しても４．２％のトータルフラックスの向上が認められ、また、実施例１に係る試料Ｎｏ．１に比しても向上が見られる（表１参照）。図３に示す表面磁束波形からもまた、比較例たる試料Ｎｏ．３及びＮｏ．４だけでなく、試料Ｎｏ．１よりも更に径方向の異方性化の均一化が顕著となっている。
【００３４】
【発明の効果】
以上のように、上部パンチを円弧状フェライト磁石の外周側とし、かつ、非磁性体とすることで、または該上部パンチ上方に磁性体を設けることで、径方向の異方性が均一であり、高特性な円弧状フェライト磁石の製造が可能となる。
【００３５】
また、前述したように更に前記各パンチが型枠に内嵌することにより成型が行われる成型方法であるため、高生産性かつ製造コストを低減することができる。
【図面の簡単な説明】
【図１】本発明に係る乾式磁場成型装置の要部断面図の一例である。
【図２】本発明に係る乾式磁場成型装置の要部断面図の他の一例である。
【図３】（ａ）は本発明の乾式磁場成型装置を用いて製造された円弧状フェライト磁石の表面磁束波形を示す図であり、（ｂ）は従来の乾式磁場成型装置を用いて製造された円弧状フェライト磁石の表面磁束波形を示す図である。
【図４】従来の乾式磁場成型装置の要部断面図である。
【符号の説明】
１、１０；型枠(非磁性体)
１ａ；シリンダ部
２；上部パンチ(非磁性体)
２ａ、３ａ；成型面
２０；上部パンチ（磁性体）
３、３０；下部パンチ(磁性体)
４、４０；成型空間
５、５０；コイル
６、６０；ステライト部
７；磁性体治具
７ａ；磁性体治具の下面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dry magnetic field molding apparatus capable of manufacturing an arc-shaped ferrite magnet having a uniform radial anisotropy and a constant surface magnetic flux density distribution at low cost and high productivity.
[0002]
[Prior art]
Motors used for home appliances and automobile electrical equipment are required to have high performance, small size, and light weight. These motors use anisotropic arc-shaped ferrite magnets or anisotropic ring-shaped ferrite magnets, and the magnets are anisotropicized so that the radial direction is the easy axis of magnetization. These ferrite magnets are required to be uniformly anisotropic in the radial direction so that the surface magnetic flux density on the inner peripheral surface side becomes stronger, and the surface magnetic flux density on the inner peripheral surface side is required to be constant in the circumferential direction.
[0003]
The manufacturing method of such an anisotropic arc-shaped ferrite magnet is roughly classified into a wet molding method and a dry molding method.
[0004]
The wet molding method provides good magnet orientation and high properties, but the molding is performed while eliminating the dispersion medium, resulting in low productivity, and the mold structure is complicated and the equipment is large. Therefore, the manufacturing cost is considerably increased.
[0005]
On the other hand, the dry molding method is inferior to the wet method in terms of magnet orientation, but the cost is low because the productivity is high and the configuration of the apparatus is simple. Among them, the molding method in which the upper punch enters the molding space of the mold and pressurizes with only the upper punch or both the upper and lower punches, the upper punch and the mold are not in contact with each other, and the mold life is reached. Long and high productivity. In addition, since the mold structure is simple and small, the manufacturing cost including the high productivity is very low.
[0006]
[Problems to be solved by the invention]
However, when using the dry molding method described above, since the upper punch and the lower punch are generally made of a magnetic material regardless of the upper and lower sides of the arc-shaped ferrite magnet, the magnetic flux lines are magnetic on the outer side. Since it also converges on the body punch, it is impossible to uniformly align in the radial direction. Further, although the orientation is controlled by the degree of providing a non-magnetic part such as stellite, it is far from the orientation that is originally required.
[0007]
In order to achieve such uniform orientation, Japanese Patent Application Laid-Open No. 5-239505 discloses a lower die of a magnetic body in a die having a required diameter and having stellite deposited on the surface thereof, and an upper die of the magnetic body. In a magnetic field press mold composed of a mold, a mold is described in which the width of the upper mold is wider than the width of the lower mold. However, since the upper punch (“upper die” in the publication) does not enter the molding space of the mold (in the same publication, “inside the die”), the mold becomes large and productive. Therefore, the superiority to the wet molding method is lost, and low cost and high productivity cannot be expected.
[0008]
Therefore, the present invention provides a dry magnetic field molding apparatus for producing an arc-shaped ferrite magnet having a high productivity and a low cost, having a uniform radial magnetic anisotropy and a constant surface magnetic flux density distribution.
[0009]
[Means for Solving the Problems]
Such an object can be achieved by the following constitution (1) or (2).
[0010]
(1) A dry magnetic field molding apparatus for arc-shaped ferrite magnets having a mold, an upper punch, and a lower punch, wherein the upper punch enters a molding space composed of the mold and the lower punch. The upper punch forms the outer peripheral side of the arc-shaped ferrite magnet and is made of a non-magnetic material, the lower punch forms the inner peripheral side of the arc-shaped ferrite magnet, and the non-magnetic material is provided on the molding surface. An arc-shaped ferrite magnet dry-type magnetic field molding apparatus characterized by comprising a magnetic material.
[0011]
(2) In the dry magnetic field molding apparatus, the upper punch has a lower surface along the arc shape of the molding surface of the upper punch , and the area of the lower surface is larger than the area of the molding surface of the upper punch. A dry magnetic field molding apparatus according to (1), wherein a large magnetic jig is attached.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The dry magnetic field molding apparatus according to the present invention will be specifically described with reference to FIGS. 1 and 2.
[0013]
FIG. 1 is an example of a dry magnetic field molding apparatus according to the present invention, and shows a cross-sectional view of the main part (near the molding part). That is, the dry magnetic field molding apparatus according to the present invention includes a mold 1, an upper punch 2, a lower punch 3, a molding space 4 composed of the mold 1 and the lower punch 3, a coil 5, an upper punch 2, and a lower punch 3. It has the stellite part 6 provided in the molding space side.
[0014]
The upper punch 2 forms the outer peripheral surface of the arc-shaped ferrite magnet (therefore, the shape of the surface of the punch forming the outer peripheral surface of the arc-shaped ferrite magnet is concave when viewed from the cross section (hereinafter referred to as the outer peripheral molding surface). 2a)), and the lower punch 3 forms the inner peripheral surface of the arc-shaped ferrite magnet (therefore, the shape of the surface of the punch that forms the inner peripheral surface of the arc-shaped ferrite magnet has a cross section thereof) And a magnetic body (hatched portion in the figure) provided with a nonmagnetic material on the inner peripheral molding surface 3a. By making the upper punch a non-magnetic material, the magnetic field direction in the molding space when a magnetic field is applied is dissipated from the lower punch. That is, the orientation of the arc-shaped ferrite magnet is not focused on the outer peripheral surface, and the orientation direction is not partially biased.
[0015]
However, if the upper punch is made of a non-magnetic material, the magnetic field strength between the upper and lower punches will deteriorate, so it will need to be higher than when the upper punch is made of a magnetic material, but the required magnetic field will depend on the area and thickness of the molded product. Therefore, the applied magnetic field may be appropriately selected depending on the molded body.
[0016]
Moreover, the material of the nonmagnetic material constituting the upper punch is not particularly limited, and for example, stainless steel, copper beryllium alloy, high manganese steel, bronze, brass, nonmagnetic super steel, etc. can be used, and two or more kinds can be used. You may combine materials. For example, as shown in FIG. 1, a stellite portion 6 is provided on the molding surface of the upper punch 2 in order to improve wear resistance and control the orientation.
[0017]
On the other hand, the material of the magnetic body constituting the lower punch is not particularly limited, and any material that is generally used can be used. For example, carbon steel, carbon tool steel, alloy tool steel, die steel, or the like is used. In addition, it is common to provide a stellite portion on the molding surface of the punch that forms the inner peripheral surface of the arc-shaped ferrite magnet in order to improve wear resistance and control the orientation. Therefore, the stellite portion 6 is also provided in the lower punch 3. Here, in addition to stellite, any nonmagnetic and wear-resistant material may be used. For example, nonmagnetic super steel or the like can be used.
[0018]
The material of the mold 1 may be a non-magnetic material, and the same material as the upper punch can be used. In addition, wear resistant materials such as nonmagnetic super steel and stellite are also provided on the inner wall surface of the molding space of the mold.
[0019]
Furthermore, in the dry magnetic field molding apparatus according to the present invention, molding is performed when the punch enters the molding space 4 composed of the mold 1 and the lower punch 3 (see FIG. 1).
[0020]
Specifically, the molding space 4 is a space excluding the portion occupied by the internally fitted lower punch 3 in the space of the cylinder portion 1 a of the mold 1. Then, the molding space 4 is filled with powder to be molded, and the upper punch 2 is molded so as to enter the molding space 4.
[0021]
The upper punch 2 and the lower punch 3 have the same width, and these widths are the same as the inner diameter of the cylinder portion 1a (however, even if the width is the same, there is naturally enough margin to allow the punch to move up and down). In addition, a taper may be provided on the upper portion of the cylinder portion 1a). Therefore, the amount of entry of the upper punch 2 into the molding space is not restricted by the mold 1. In other words, since the vertical movement is not restricted by providing a step in the upper punch or the mold and contacting the upper punch and the mold with the surface, the mold life is long and the productivity is high. Further, since the mold structure is simple and small, the manufacturing cost including the high productivity of the arc-shaped ferrite magnet is very low.
[0022]
As shown in FIG. 2, the dry magnetic field molding apparatus according to the present invention mounts a magnetic jig 7 having a lower surface 7 a having a shape along the arc of the molding surface 2 a of the upper punch above the upper punch 2. Is preferred. By providing the magnetic body jig 7 on the upper punch side made of a non-magnetic material, the magnetic field strength in the molding space is increased, and the shape of the lower surface 7a of the magnetic body jig 7 is configured along the molding surface of the upper punch. This is because complete radial orientation is possible. The area of the lower surface 7a of the magnetic jig 7 may be increased to such an extent that the end portion orientation of the arc-shaped ferrite magnet is not biased. The material may be a normal magnetic material such as carbon steel, carbon tool steel, alloy tool steel, or die steel.
[0023]
Next, the configuration other than the molding unit of the dry magnetic field molding apparatus according to the present invention will be described.
[0024]
Usually, the framework of the magnetic field shaping apparatus is made of a magnetic material, and has a mechanism capable of forming a closed magnetic path when a magnetic field is applied. The molding apparatus main body of the present invention is also made of a magnetic material, and the mounting portions (not shown) of the upper punch 2 and the lower punch 3 are magnetic materials. That is, although the upper punch is made of a non-magnetic material, the upper punch mounting portion is a magnetic material, so that the entire molding apparatus can form a closed magnetic path when a magnetic field is applied. Here, the material of the magnetic body may be a normal magnetic body as in the case of the magnetic body, and for example, carbon steel, carbon tool steel, alloy tool steel, die steel and the like are used.
[0025]
【Example】
Specific examples of the present invention will be described below.
[0026]
<Example 1>
A strontium ferrite material powder was molded in a magnetic field using the dry molding apparatus shown in FIG. Here, the non-magnetic upper punch 2 is made of stainless steel SUS304, the magnetic lower punch 3 is made of alloy tool steel SKS2, and both are formed by welding the stellite portion 6 to the molding surfaces 2a and 3a. It was. The obtained molded body was fired at 1240 ° C. and subjected to surface processing, and then an arc-shaped ferrite magnet (sample No. 1) was obtained. Subsequently, the total flux and the surface magnetic flux waveform were measured with a gauss meter using a flux meter.
[0027]
The results are shown in Table 1 and FIG. Here, the improvement rate in Table 1 is the following sample No. The improvement rate of the total flux with respect to 3.
[0028]
For comparison, as shown in FIG. 4, the upper punch 20 is made of a magnetic material, and the lower punch 30 is made of a magnetic material having a non-magnetic stellite portion 60 on the molding surface. Molding was performed in a magnetic field by a conventional dry molding apparatus in which molding is performed by fitting 30 to the mold 10. Further, in the dry molding apparatus shown in FIG. 4, the molding surface of the upper punch 20 was also molded in the same manner using a material in which stellite was welded for orientation control. Here, the magnetic material of the upper punch 20 and the lower punch 30 used is SKS2. The obtained molded body was processed in the same manner as above (sample No. 3 and sample No. 4 respectively), and the total flux and the surface magnetic flux waveform were measured.
[0029]
[Table 1]
Figure 0004057092
[0030]
The effects of the present invention are apparent from Table 1 and FIG. That is, the arc-shaped ferrite magnet created by the dry magnetic field molding apparatus according to the present invention has the sample No. 2 created by the upper punch made of a magnetic material. In addition to sample No. 3, sample No. 3 was prepared by welding stellite to control orientation. Compared to 4, the total flux is improved by 3.3% (see Table 1). Moreover, when the surface magnetic flux waveform shown in FIG. 3 is seen, it turns out that especially the magnetic flux density of the edge part of the inner peripheral side of an arc-shaped ferrite magnet is improving, and it is made anisotropic uniformly in radial direction.
[0031]
<Example 2>
2 except that the magnetic jig 7 is mounted above the upper punch 2 and the same operation as in Example 1 is performed, and the total flux of the obtained sample (sample No. 2) and The surface magnetic flux waveform was measured. The lower surface 7a of the magnetic jig 7 used was shaped so as to be concentric with the arc of the molding surface 2a of the upper punch 2 when the upper punch 2 was positioned immediately before the completion of molding.
[0032]
The results are shown in Table 1 and FIG.
[0033]
The effects of the present invention are apparent from Table 1 and FIG. That is, the sample No. prepared by the upper punch made of a magnetic material. In addition to sample No. 3, sample No. 3 was prepared by welding stellite to control orientation. 4 and 4.2% of the total flux improvement was observed, and Sample No. An improvement is also seen compared to 1 (see Table 1). From the surface magnetic flux waveform shown in FIG. 3 and no. 4 as well as sample no. Even more uniform than 1 in the radial anisotropy.
[0034]
【The invention's effect】
As described above, the anisotropy in the radial direction is uniform by making the upper punch the outer peripheral side of the arc-shaped ferrite magnet and making it a non-magnetic material, or by providing a magnetic material above the upper punch. This makes it possible to produce a high-characteristic arc-shaped ferrite magnet.
[0035]
Further, as described above, since the molding is performed by further fitting each punch into the mold, high productivity and manufacturing cost can be reduced.
[Brief description of the drawings]
FIG. 1 is an example of a cross-sectional view of a main part of a dry magnetic field molding apparatus according to the present invention.
FIG. 2 is another example of a cross-sectional view of the main part of the dry magnetic field molding apparatus according to the present invention.
FIG. 3A is a diagram showing a surface magnetic flux waveform of an arc-shaped ferrite magnet manufactured using the dry magnetic field molding apparatus of the present invention, and FIG. 3B is manufactured using a conventional dry magnetic field molding apparatus. It is a figure which shows the surface magnetic flux waveform of a circular arc ferrite magnet.
FIG. 4 is a cross-sectional view of a main part of a conventional dry magnetic field molding apparatus.
[Explanation of symbols]
1, 10; Formwork (non-magnetic material)
1a; cylinder part 2; upper punch (non-magnetic material)
2a, 3a; molding surface 20; upper punch (magnetic material)
3, 30; Lower punch (magnetic material)
4, 40; molding space 5, 50; coil 6, 60; stellite portion 7; magnetic jig 7a;

Claims (2)

型枠と上部パンチと下部パンチと有し、前記上部パンチが前記型枠と前記下部パンチから構成される成型空間に進入して成型が為される円弧状フェライト磁石の乾式磁場成型装置において、上部パンチは円弧状フェライト磁石の外周側を形成し、かつ、非磁性体からなり、下部パンチは円弧状フェライト磁石の内周側を形成し、かつ、その成型面に非磁性体を設けた磁性体からなることを特徴とする円弧状フェライト磁石の乾式磁場成型装置。In a dry magnetic field molding apparatus of an arc-shaped ferrite magnet having a mold, an upper punch, and a lower punch, and the upper punch enters a molding space constituted by the mold and the lower punch, and molding is performed. The punch forms the outer peripheral side of the arc-shaped ferrite magnet and is made of a non-magnetic material, and the lower punch forms the inner peripheral side of the arc-shaped ferrite magnet and has a non-magnetic material on the molding surface An arc-shaped ferrite magnet dry magnetic field molding apparatus characterized by comprising: 前記乾式磁場成型装置において、前記上部パンチの上方に上部パンチの成型面の円弧形状に沿った形状の下面を有し、かつ、前記下面の面積が前記上部パンチの成型面の面積より大きい磁性体治具を装着してなることを特徴とする請求項１に記載の乾式磁場成型装置。In the dry magnetic field molding apparatus, a magnetic body having a lower surface along the arc shape of the molding surface of the upper punch above the upper punch , and the area of the lower surface is larger than the area of the molding surface of the upper punch The dry magnetic field molding apparatus according to claim 1, wherein a jig is attached.
JP07017397A 1997-03-24 1997-03-24 Dry magnetic field molding equipment for arc-shaped ferrite magnets Expired - Lifetime JP4057092B2 (en)

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US7014811B2 (en) 2001-07-02 2006-03-21 Neomax Co., Ltd. Method for producing rare earth sintered magnets
JP4134616B2 (en) 2001-10-02 2008-08-20 日立金属株式会社 Press apparatus and magnet manufacturing method
JP5120534B2 (en) * 2006-03-15 2013-01-16 Ｔｄｋ株式会社 Anisotropic ferrite magnet and motor
JP5870567B2 (en) * 2010-09-10 2016-03-01 Tdk株式会社 Bow magnets and magnetic field molds
JP5968735B2 (en) * 2012-09-13 2016-08-10 ゼノー・テック株式会社 Lower punch used for forming a ferrite magnet in a magnetic field, and method for manufacturing the lower punch
CN103071792B (en) * 2013-01-25 2016-08-03 无锡钻探工具厂有限公司 A kind of curved plate forming mold of hard alloy
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