JPH10177928A - Molding device for cylindrical radial anisotropic magnet - Google Patents

Molding device for cylindrical radial anisotropic magnet

Info

Publication number
JPH10177928A
JPH10177928A JP32463196A JP32463196A JPH10177928A JP H10177928 A JPH10177928 A JP H10177928A JP 32463196 A JP32463196 A JP 32463196A JP 32463196 A JP32463196 A JP 32463196A JP H10177928 A JPH10177928 A JP H10177928A
Authority
JP
Japan
Prior art keywords
die
magnetic
cavity
molding
magnetic field
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.)
Granted
Application number
JP32463196A
Other languages
Japanese (ja)
Other versions
JP3774876B2 (en
Inventor
Akihiro Izui
章広 泉井
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Minebea Co Ltd
Original Assignee
Minebea Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Minebea Co Ltd filed Critical Minebea Co Ltd
Priority to JP32463196A priority Critical patent/JP3774876B2/en
Publication of JPH10177928A publication Critical patent/JPH10177928A/en
Application granted granted Critical
Publication of JP3774876B2 publication Critical patent/JP3774876B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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
    • H01F41/0273—Imparting anisotropy
    • H01F41/028—Radial anisotropy

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)
  • Powder Metallurgy (AREA)

Abstract

PROBLEM TO BE SOLVED: To enable manufacturing a high-performance radial anisotropic magnet having a long cylindrical length by decreasing the magnetic-field component in the axial direction in a cavity. SOLUTION: At the outer surface of a die 10 of a molding die 1, four or more protruding parts 12 are provided in a radial pattern at equal intervals. A coil 13 is wound around each protruding part 12. A current is made to flow through each coil 13 so that the same magnetic pole is directed to the center of the die 10. The magnetic field generated in the protruding part 12 is made to cross the radial direction in a cavity 9 and collected at the center of the die 10. The magnetic field is reflected from the center of the die 10 and made to flow to the vertical directions in a core rod 5. The magnetic powder in the cavity 9 is radially oriented, compressed and molded.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、磁性粉末を放射状
に配向（ラジアル配向）させたラジアル異方性磁石を成
形するための成形装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding apparatus for molding a radially anisotropic magnet in which magnetic powder is radially oriented (radially oriented).

【０００２】[0002]

【従来の技術】一般に、磁性粉末を成形型のキャビテイ
内に入れて単に圧縮成形した場合は、磁性粉末のもつ内
部磁気モーメントの方向がランダムとなり、等方性の磁
石となって、得られる磁気性能はそれほど高くならな
い。これに対して、成形型内に磁界を形成してこの磁界
内に磁性粉末をおくと、磁性粉末が磁化方向に整列し、
そのまま圧縮成形することで内部磁気モーメントの方向
の整った、いわゆる異方性の磁石となり、磁気性能に優
れたものとなる。ところで、ＨＤＤ、ＭＯ、ＣＤ−ＲＯ
Ｍ、ＤＶＤ用等のモータには円筒状磁石が用いられてお
り、これを異方性磁石として製造するには、磁性粉末を
ラジアル配向させる必要がある。2. Description of the Related Art In general, when a magnetic powder is simply placed in a cavity of a molding die and compression-molded, the direction of an internal magnetic moment of the magnetic powder becomes random, and the magnetic powder obtained becomes an isotropic magnet. Performance is not so high. On the other hand, when a magnetic field is formed in the mold and the magnetic powder is placed in the magnetic field, the magnetic powder is aligned in the magnetization direction,
By performing compression molding as it is, it becomes a so-called anisotropic magnet in which the direction of the internal magnetic moment is adjusted, and the magnetic performance is excellent. By the way, HDD, MO, CD-RO
A cylindrical magnet is used for a motor for M, DVD, and the like. In order to manufacture this as an anisotropic magnet, it is necessary to radially orient magnetic powder.

【０００３】図７〜９は、このように磁性粉末をラジア
ル配向させるための従来の成形装置を示したもので、成
形型１とこの成形型１内にラジアル磁界を形成するため
の下および上コイル２、３とを備えている。成形型１
は、リング状ダイス４と、このダイス４の孔中心に配置
された下コアロッド５と、この下コアロッド５の上方に
昇降可能に配置された上コアロッド６と、ダイス４と下
コアロッド５との間隙に挿入可能な下および上パンチ
７，８とからなっており、上・下コイル３，２はダイス
４の上下に対向して配置されるようなっている。なお、
これらダイス４、上・下コアロッド６，５等は磁性材料
から形成されている。FIGS. 7 to 9 show a conventional molding apparatus for radially orienting a magnetic powder in such a manner. A molding die 1 and lower and upper portions for forming a radial magnetic field in the molding die 1 are shown. And coils 2 and 3. Mold 1
A ring-shaped die 4, a lower core rod 5 disposed at the center of a hole of the die 4, an upper core rod 6 disposed above the lower core rod 5 so as to be able to move up and down, and a gap between the die 4 and the lower core rod 5. The upper and lower coils 3 and 2 are arranged so as to be opposed to the upper and lower sides of the die 4. In addition,
The dies 4, the upper and lower core rods 6, 5 and the like are formed of a magnetic material.

【０００４】成形に際しては、予め位置固定のダイス４
および下コアロッド５に対して、上コアロッド６、上パ
ンチ８および上コイル２の上側機構部を上昇させると共
に、ダイス４と下コアロッド５との間隙に下パンチ７を
わずか挿入した状態とし、ダイス４と、下コアロッド５
と下パンチ７とで囲まれた環状のキャビテイ９内に、適
宜のフィーダ（図示略）を用いて磁性粉末（ボンド磁石
とする場合は、バインダーと混合した磁性粉末）を充填
する。その後、前記上側機構部を下降させて、上コアロ
ッド６は下コアロッド５に当接させ、上パンチ８はキャ
ビテイ９内にわずか挿入させ、上コイル３はダイス４上
に載置する。次に、下および上コイル２，３に電流（通
常、パルス電流）を供給し、コアロッド５，６に同磁極
が対向するように磁界を印加する。すると、図９、１０
および１１に示すように、ダイス４内の中央部を境とし
て磁界が反発し、ダイス４内に放射方向のラジアル磁界
が形成され、このラジアル磁界によりキャビテイ９内の
磁性粉末がラジアル配向するようになる。したがって、
その後、下パンチ７と上パンチ８とを相対的に接近させ
て圧縮成形を行えば、円筒状のラジアル異方性磁石（成
形体）が得られるようになる。At the time of molding, a fixed die 4
The upper mechanism of the upper core rod 6, the upper punch 8, and the upper coil 2 is raised with respect to the lower core rod 5, and the lower punch 7 is slightly inserted into the gap between the die 4 and the lower core rod 5, so that the die 4 And the lower core rod 5
Using a suitable feeder (not shown), a magnetic powder (or a magnetic powder mixed with a binder when a bonded magnet is used) is filled in an annular cavity 9 surrounded by the lower punch 7 and the lower cavity 7. Thereafter, the upper mechanism is lowered to bring the upper core rod 6 into contact with the lower core rod 5, the upper punch 8 is slightly inserted into the cavity 9, and the upper coil 3 is placed on the die 4. Next, a current (usually a pulse current) is supplied to the lower and upper coils 2 and 3, and a magnetic field is applied to the core rods 5 and 6 such that the same magnetic poles face each other. Then, FIGS.
As shown in FIGS. 11A and 11B, the magnetic field repels at the center of the die 4 and forms a radial magnetic field in the radial direction in the die 4. The radial magnetic field causes the magnetic powder in the cavity 9 to be radially oriented. Become. Therefore,
Thereafter, when the lower punch 7 and the upper punch 8 are relatively close to each other and compression molding is performed, a cylindrical radial anisotropic magnet (compact) can be obtained.

【０００５】[0005]

【発明が解決しようとする課題】しかしながら、上記し
た従来の成形装置によれば、図１０および１１に示すよ
うに、上・下パンチ８，７により閉じられたキャビテイ
９を通る磁束がキャビテイ９の上、下底付近で軸方向へ
流れる、すなわち軸方向の磁界成分が増加する傾向にあ
る。そして、この軸方向の磁界成分の増加傾向は、図１
０および１１の比較からも分かるように、下コアロッド
５の直径ｄ1 に対してキャビテイ９の軸方向長さｄ2
（図７）が大きくなるほど顕著となり、特に、キャビテ
イ長さｄ2 がコアロッド径ｄ1 の２倍以上となる場合
は、得られる磁石の磁化強さに軸方向で大きな強弱が生
じ、実質、その製品化は断念せざるを得ない状況にあっ
た。However, according to the above-mentioned conventional molding apparatus, as shown in FIGS. 10 and 11, the magnetic flux passing through the cavity 9 closed by the upper and lower punches 8 and 7 causes the magnetic flux of the cavity 9 to be reduced. There is a tendency that the magnetic field component flows in the axial direction near the upper and lower bottoms, that is, the axial magnetic field component increases. The increasing tendency of the axial magnetic field component is shown in FIG.
As can be seen from the comparison between 0 and 11, the axial length d 2 of the cavity 9 is compared with the diameter d 1 of the lower core rod 5.
(Figure 7) becomes remarkable as increases, in particular, cavities if the length d 2 is twice or more core rod diameter d 1, the major strength occurs in the axial direction to the magnetization intensity of the resulting magnet, substantially, its Commercialization had to be abandoned.

【０００６】なお、キャビテイ９の上、下底と上・下コ
イル３，２との距離ｄ3 （図７）を大きく設定すること
により、上記軸方向の磁界成分を少なくすることができ
るが、この場合は、ラジアル磁界の強度が低下して磁性
粉末のラジアル配向は困難とり、根本的な解決にはなら
ない。The axial magnetic field component can be reduced by setting the distance d 3 (FIG. 7) between the upper and lower bottoms of the cavity 9 and the upper and lower coils 3 and 2 large. In this case, the strength of the radial magnetic field is reduced and the radial orientation of the magnetic powder is difficult, and this is not a fundamental solution.

【０００７】本発明は、上記従来の問題点に鑑みてなさ
れたもので、その課題とするところは、従来の上下反発
方式に代えて横方向反発方式でラジアル磁界を形成する
ことにより、キャビテイ内における軸方向の磁界成分を
低減し、もって円筒長の長い高性能なラジアル異方性磁
石を安定して得ることができるようにすることにある。SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. An object of the present invention is to form a radial magnetic field by using a lateral repulsion method instead of the conventional vertical repulsion method, so that the inside of the cavity is reduced. The objective of the present invention is to reduce the axial magnetic field component and to stably obtain a high-performance radial anisotropic magnet having a long cylindrical length.

【０００８】[0008]

【課題を解決するための手段】本発明は、上記課題を解
決するため、磁性材料製のダイスと、該ダイスの孔中心
に配置した磁性材料製のコアロッドと、ダイスとコアロ
ッドとの間隙に挿入される非磁性材料製の上、下パンチ
とからなる成形型を備え、前記成形型内にコイルにより
ラジアル磁界を形成し、このラジアル磁界内で成形型の
キャビテイ内に入れた磁性粉末をラジアル配向させて圧
縮成形する円筒状ラジアル異方性磁石の成形装置におい
て、前記成形型のダイスの外周に、その周方向に等配し
て少なくとも４つの突出部を放射状に設け、前記各突出
部に前記コイルを巻装して、ダイス中心に同磁極を指向
させるようにしたことを特徴とする。In order to solve the above-mentioned problems, the present invention provides a die made of a magnetic material, a core rod made of a magnetic material disposed at the center of a hole of the die, and a gap inserted between the die and the core rod. A molding die comprising upper and lower punches made of a non-magnetic material to be formed, forming a radial magnetic field by a coil in the molding die, and radially orienting the magnetic powder put in the cavity of the molding die in the radial magnetic field. In a molding apparatus for a cylindrical radial anisotropic magnet, which is compression molded by being provided, at least four projections are provided radially on the outer periphery of the die of the molding die and are equally arranged in the circumferential direction, and the projections are formed on each of the projections. The coil is wound so that the same magnetic pole is directed to the center of the die.

【０００９】このように構成した成形装置では、ダイス
の外周に設けた突出部に巻装したコイルに通電すると、
各突出部が磁化して、磁束が成形型のダイス中を半径方
向へ流れてキャビテイを横断し、コアロッドを軸方向へ
流れる。したがって、磁芯となる突出部を、キャビテイ
の軸方向長さに応じた適当な長さに設定することで、キ
ャビテイ内にほゞ一様にラジアル磁界が形成される。[0009] In the molding apparatus configured as described above, when the coil wound around the protrusion provided on the outer periphery of the die is energized,
Each protrusion magnetizes and magnetic flux flows radially through the die of the mold, across the cavity, and axially through the core rod. Therefore, the radial magnetic field is formed almost uniformly in the cavity by setting the protrusion serving as the magnetic core to an appropriate length according to the axial length of the cavity.

【００１０】本発明は、上記したように磁芯となる突出
部を少なくとも４つ設けたことを特徴とするが、これよ
り少ない場合は、突出部の相互間に位置するキャビテイ
領域で、磁束のラジアル方向の整列性が悪化し、磁性粉
末のラジアル配向度が低下する。一方、この突出部の数
を増すほど、ラジアル磁界の強度は増大してラジアル配
向度を高める上で有利となるが、ダイスやコイルの大き
さとの関係で一定の制約があり、この突出部の数は、通
常、６つ程度が限度となる。このように突出部を４つ以
上設けることで、各突出部に対するコイルの巻き数を減
らしても、所定のラジアル磁界強度を得ることができ
る。このことは、コイル中を流れる電流による電力損失
が少なくなることを意味し、これによってコイル発熱が
抑制され、突出部の存在でダイスの放熱面積が大きくな
っていることと相まって、成形型の温度上昇が抑えられ
る。因みに、前記した従来の成形装置（図７）では、所
定のラジアル磁界強度を得ようとすると、用いるコイル
２、３が大型となってその発熱による成形型の温度上昇
が大きく、場合によっては空冷のみでは不十分で、水に
よる冷却が必要になって、その構造は複雑となる。The present invention is characterized in that at least four protrusions serving as magnetic cores are provided as described above. If the number of protrusions is less than four, a cavity region located between the protrusions is used to reduce the magnetic flux. The alignment in the radial direction deteriorates, and the degree of radial orientation of the magnetic powder decreases. On the other hand, as the number of the protrusions increases, the strength of the radial magnetic field increases, which is advantageous in increasing the degree of radial orientation, but there are certain restrictions in relation to the size of the die and the coil. The number is usually limited to about six. By providing four or more protrusions in this manner, a predetermined radial magnetic field intensity can be obtained even when the number of turns of the coil around each protrusion is reduced. This means that the power loss due to the current flowing through the coil is reduced, which suppresses the heat generation of the coil and, together with the fact that the heat dissipation area of the die is increased due to the presence of the protrusion, the temperature of the molding die is reduced. The rise is suppressed. Incidentally, in the above-mentioned conventional molding apparatus (FIG. 7), in order to obtain a predetermined radial magnetic field strength, the coils 2 and 3 used become large, and the temperature rise of the molding die due to the heat generated is large. This alone is not enough and requires water cooling, which complicates the structure.

【００１１】本発明において、成形型内にラジアル磁界
を形成するには、コイルにパルス電流または直流電流を
流すが、従来の成形装置では、上記したようにコイル発
熱が大きいため、直流電流の連続印加は実質断念せざる
を得ない状況にあった。しかし、本発明の場合は、上記
したようにコイル発熱が小さいので、直流電流の連続印
加が可能になり、例えば、圧縮成形中も直流を流して磁
性粉末のラジアル配向を保持することができ、異方性の
高い磁石を得ることができる。In the present invention, in order to form a radial magnetic field in a molding die, a pulse current or a DC current is applied to the coil. There was a situation where the application had to be substantially abandoned. However, in the case of the present invention, since the coil heat is small as described above, it is possible to continuously apply a direct current, for example, it is possible to maintain the radial orientation of the magnetic powder by flowing a direct current even during compression molding, A highly anisotropic magnet can be obtained.

【００１２】また本発明において、上記磁芯となる突出
部の軸方向長さは、キャビテイの軸方向長さの少なくと
も９０％に設定するのが望ましい。これより短いと、キ
ャビテイの上または下底付近における軸方向の磁界成分
が増大する。この突出部の軸方向長さの上限は、特に規
定しないが、キャビテイの軸方向長さと同等かそれより
わずか長くすれば十分である。In the present invention, it is desirable that the axial length of the protrusion serving as the magnetic core is set to at least 90% of the axial length of the cavity. If it is shorter than this, the axial magnetic field component near the upper or lower bottom of the cavity increases. The upper limit of the axial length of the protrusion is not particularly limited, but it is sufficient that the length is equal to or slightly longer than the axial length of the cavity.

【００１３】また本発明において、上記ダイスおよびコ
アロッドの材料としては、透磁率および飽和磁束密度が
高く、かつ耐摩耗性に優れた材料を選択するのが望まし
い。このような材料としては、例えば炭素工具鋼(SK)、
合金工具鋼(SKS,SKD) 、高速度工具鋼(SKH) 等の金型材
料がある。また、耐摩耗性を重視する場合は、高透磁率
および高飽和磁束密度を有する基材、例えばパーマロイ
材、センダスト材等に超硬合金の被覆層を設ける構成と
することができる。この場合、被覆層は、スリーブとし
て別体に形成して、基材に接合一体化するようにしても
良い。In the present invention, it is desirable to select a material having a high magnetic permeability and a high saturation magnetic flux density and excellent wear resistance as the material of the die and the core rod. Such materials include, for example, carbon tool steel (SK),
There are mold materials such as alloy tool steel (SKS, SKD) and high speed tool steel (SKH). When importance is placed on wear resistance, a structure in which a coating layer of a cemented carbide is provided on a substrate having a high magnetic permeability and a high saturation magnetic flux density, for example, a permalloy material, a sendust material, or the like can be used. In this case, the coating layer may be formed separately as a sleeve and joined and integrated with the base material.

【００１４】本発明は、焼結磁石はもとよりボンド磁石
の成形にも適用できるものである。ボンド磁石の成形に
適用する場合は、バインダーを加えた磁性粉末を成形型
のキャビテイ内に充填する。この場合のバインダーとし
ては、エポキシ樹脂やフェノール樹脂などの熱硬化性樹
脂を選択することができる。なお、ボンド磁石を完成さ
せるには、成形後に 120℃程度でキュア処理を行う。The present invention can be applied not only to the formation of a sintered magnet but also to the formation of a bonded magnet. When applied to the formation of a bonded magnet, a magnetic powder to which a binder has been added is filled in the cavity of a mold. In this case, a thermosetting resin such as an epoxy resin or a phenol resin can be selected as the binder. To complete the bonded magnet, a curing treatment is performed at about 120 ° C. after molding.

【００１５】[0015]

【発明の実施の形態】以下、本発明の実施の形態を添付
図面に基いて説明する。Embodiments of the present invention will be described below with reference to the accompanying drawings.

【００１６】図１〜３は、本発明の第１の実施の形態を
示したものである。なお、第１の実施の形態としての成
形装置の全体構成は、前出図７〜９に示したものと基本
的に同じであるので、ここでは、同一部分には同一符号
を付し、それらの説明を省略することとする。本第１の
実施の形態において、成形型１を構成するダイス１０
は、リング状の本体部１１と、この本体部１１の外周
に、その周方向に等配して（９０度間隔で）設けられた
４つの突出部１２とを備えている。ダイス１０の各突出
部１２は、角柱状をなし、本体部１１と同じ軸方向長さ
（高さ）を有している。また各突出部１２は、本体部１
１に対してその半径外方向へ延びるように突設されてお
り、したがって４つの突出部１２は、本体部１１の外側
に放射状をなすように配置されている。なお、ダイス１
０および上・下コアロッド６，５は、汎用の金型材料、
例えば炭素工具鋼(SK)、合金工具鋼(SKS,SKD) 、高速度
工具鋼(SKH) 等から形成され、上・下パンチ８，７は非
磁性の材料から形成されている。FIGS. 1 to 3 show a first embodiment of the present invention. Since the overall configuration of the molding apparatus according to the first embodiment is basically the same as that shown in FIGS. 7 to 9 described above, the same parts are denoted by the same reference numerals, and Will be omitted. In the first embodiment, the dies 10 constituting the molding die 1
Is provided with a ring-shaped main body 11 and four protrusions 12 provided on the outer periphery of the main body 11 at equal intervals in the circumferential direction (at 90-degree intervals). Each projection 12 of the die 10 has a prismatic shape, and has the same axial length (height) as the main body 11. Further, each protruding portion 12 is provided on the
1 is protruded so as to extend in the radially outward direction, and thus the four protrusions 12 are arranged radially outside the main body 11. Die 1
0 and upper and lower core rods 6 and 5 are general-purpose mold materials,
For example, it is made of carbon tool steel (SK), alloy tool steel (SKS, SKD), high speed tool steel (SKH), etc., and the upper and lower punches 8 and 7 are made of non-magnetic material.

【００１７】一方、各突出部１２には、成形型１内にラ
ジアル磁界を形成するためのコイル１３（１３Ａ，１３
Ｂ，１３Ｃ，１３Ｄ）が巻装されている。各コイル１３
には、電源（図示略）から電流が供給されるようになっ
ており、この電流供給によって各突出部１２は磁化し、
その磁界がダイス１０の中を半径方向へ流れるようにな
る（図１）。しかして、各突出部１２のコイル１３に
は、同一磁極がダイス１０の中心に指向するように電流
が供給されるようになっており、これにより、各突出部
１２に発生した磁界は、図４および５に示すように、ダ
イス１０の中心で横方向で相互に反発してコアロッド
５、６に沿って流れるようになる。On the other hand, each projecting portion 12 has a coil 13 (13A, 13A) for forming a radial magnetic field in the molding die 1.
B, 13C, and 13D). Each coil 13
, A current is supplied from a power supply (not shown), and each of the protrusions 12 is magnetized by this current supply.
The magnetic field flows in the die 10 in the radial direction (FIG. 1). The current is supplied to the coil 13 of each protrusion 12 so that the same magnetic pole is directed to the center of the die 10, whereby the magnetic field generated in each protrusion 12 is As shown in FIGS. 4 and 5, the center of the die 10 repels each other in the lateral direction and flows along the core rods 5, 6.

【００１８】上記した成形装置による成形手順は、前記
した従来の成形装置（図７、８）による手順と同じであ
り、予め上コアロッド６および上パンチ８を上昇させ
て、ダイス１０と、下コアロッド５と下パンチ７とで囲
まれた環状のキャビテイ９内にフィーダを用いて磁性粉
末（ボンド磁石とする場合は、バインダーと混合した磁
性粉末）を充填する。その後、上コアロッド６および上
パンチ８を下降させ、上コアロッド６は下コアロッド５
に当接させる一方で、上パンチ８はキャビテイ９内にわ
ずか挿入させてキャビテイ９を閉じる。The molding procedure by the above-described molding apparatus is the same as the procedure by the above-mentioned conventional molding apparatus (FIGS. 7 and 8). The upper core rod 6 and the upper punch 8 are raised in advance, and the die 10 and the lower core rod are moved. Using a feeder, a magnetic powder (or a magnetic powder mixed with a binder when a bonded magnet is used) is filled in an annular cavity 9 surrounded by the lower punch 5 and the lower punch 7. Thereafter, the upper core rod 6 and the upper punch 8 are lowered, and the upper core rod 6 is
The upper punch 8 is slightly inserted into the cavity 9 to close the cavity 9.

【００１９】次に、各コイル１３Ａ，１３Ｂ，１３Ｃ，
１３Ｄに電流（パルス電流）を供給し、ダイス１０の各
突出部１２を磁化する。この時、ダイス中心側がＮ極と
なるように各突出部１２を磁化すると、この磁化により
発生した磁束は、図１に矢印にて示すように、ダイス１
０の中を半径内方向へ流れ、キャビテイ９内を直角に横
断してダイス中心に向かい、さらに図４および５に示す
ように、ダイス中心で相互に反発してコアロッド５、６
を上下方向へ抜ける。これにより、キャビテイ９内の磁
性粉末はラジアル配向し、その後、下パンチ７と上パン
チ８とを相対的に接近させて圧縮成形を行えば、円筒状
のラジアル異方性磁石（成形体）が得られるようにな
る。Next, each of the coils 13A, 13B, 13C,
A current (pulse current) is supplied to 13D to magnetize each protrusion 12 of the dice 10. At this time, when each projection 12 is magnetized so that the center of the die becomes an N pole, the magnetic flux generated by this magnetization is applied to the die 1 as shown by an arrow in FIG.
0, radially inward, traversing the cavity 9 at right angles to the center of the die, and further repelling each other at the center of the die as shown in FIGS.
Through the vertical direction. As a result, the magnetic powder in the cavity 9 is radially oriented, and then the lower punch 7 and the upper punch 8 are relatively close to each other for compression molding, so that a cylindrical radial anisotropic magnet (compact) is formed. Will be obtained.

【００２０】ここで、本成形装置において成形型１内に
発生する磁束は、図４および図５を用いて説明したよう
にダイス中心で反発してコアロッド５、６に流れるが、
この状態を前出図１０、図１１に示した従来のものと比
較すると、キャビテイ９の軸方向長さが短い場合（図４
と図１０）は、本発明の成形装置と従来の成形装置とで
軸方向の磁界成分にそれほどの差異は認められない。し
かし、キャビテイ９の軸方向長さが長い場合（図５と図
１１）は、本発明の成形装置の方が従来の成形装置より
も明らかに軸方向の磁界成分が少なくなっている。Here, the magnetic flux generated in the molding die 1 in the present molding apparatus repels at the center of the die and flows to the core rods 5 and 6 as described with reference to FIGS.
When this state is compared with the prior art shown in FIGS. 10 and 11, the case where the length of the cavity 9 in the axial direction is short (FIG.
10 and FIG. 10), there is no significant difference in the axial magnetic field component between the molding apparatus of the present invention and the conventional molding apparatus. However, when the length of the cavity 9 in the axial direction is long (FIGS. 5 and 11), the molding device of the present invention clearly has a smaller axial magnetic field component than the conventional molding device.

【００２１】図６は、本発明の第２の実施の形態を示し
たものである。本第２の実施の形態の特徴とするところ
は、ダイス１０の本体部１１の孔内面と、下コアロッド
５の外周面とに超硬合金のスリーブ１５、１６をそれぞ
れ嵌合した点にある。この場合、ダイス１０および下コ
アロッド５の基材としては、高透磁率および高飽和磁束
密度を有す材料、例えばパーマロイ材、センダスト材等
を選択するものとする。また各スリーブ１５、１６の厚
さは、あまり厚いと、成形型１内に形成されるラジアル
磁界強度を低下させるので、１〜５mm範囲の適当な厚さ
とするのが望ましい。FIG. 6 shows a second embodiment of the present invention. A feature of the second embodiment is that cemented carbide sleeves 15 and 16 are fitted to the inner surface of the hole of the main body 11 of the die 10 and the outer surface of the lower core rod 5, respectively. In this case, as the base material of the die 10 and the lower core rod 5, a material having high magnetic permeability and high saturation magnetic flux density, for example, a permalloy material, a sendust material, or the like is selected. If the thickness of each of the sleeves 15 and 16 is too large, the radial magnetic field intensity formed in the molding die 1 is reduced. Therefore, it is desirable that the sleeves 15 and 16 have an appropriate thickness in the range of 1 to 5 mm.

【００２２】このようにダイス１０の孔内面と下コアロ
ッド５の外周面とに超硬合金のスリーブ１５、１６を配
置することで、ダイス１０および下コアロット５の耐摩
耗性が向上し、成形型１の寿命が著しく延長する。ま
た、ダイス１０および下コアロット５の基材として高透
磁率および高飽和磁束密度を有する材料を用いているの
で、成形型１内には、磁性粉末の配向に必要なラジアル
磁界強度が確保され、所望の磁気特性を有する円筒状ラ
ジアル異方性磁石を製造できる。By arranging the cemented carbide sleeves 15 and 16 on the inner surface of the hole of the die 10 and the outer peripheral surface of the lower core rod 5, the wear resistance of the die 10 and the lower core lot 5 is improved, and the forming die 1 is significantly extended. Further, since a material having a high magnetic permeability and a high saturation magnetic flux density is used as the base material of the die 10 and the lower core lot 5, a radial magnetic field strength required for the orientation of the magnetic powder is secured in the molding die 1, A cylindrical radial anisotropic magnet having desired magnetic properties can be manufactured.

【００２３】[0023]

【実施例】以下、本発明の実施例を説明する。磁芯とし
ての突出部１２を２、３、４、５、６個設け、かつ孔内
面に超硬合金のスリーブ１５（図６）を配置したダイス
モデルと、外周面に超硬合金のスリーブ１６（図６）を
配置したコアロッドモデルとを作製し、ダイスモデルの
各突出部１２には巻き数４０ターンのコイル１３を配置
した。ここで、ダイスモデルおよびコアロッドモデルの
作製に際しては、それぞれの基材としてパーマロイ材
（ＴＭＢ）を用い、各基材に嵌合するスリーブ１５、１
６の厚さは１mmとした。また、ダイスモデルの孔内径は
22mm，その軸方向長さは40mm，コアロッドモデルの直径
は19mmとし、これらダイスモデルとコアロッドモデルと
の間隙（キャビテイ９）を1.5mm に設定した。Embodiments of the present invention will be described below. A die model in which two, three, four, five and six protruding portions 12 are provided as a magnetic core, and a cemented carbide sleeve 15 (FIG. 6) is disposed on the inner surface of the hole, and a cemented carbide sleeve 16 on the outer peripheral surface. A core rod model in which (FIG. 6) was arranged was prepared, and a coil 13 having 40 turns was arranged in each projecting portion 12 of the die model. Here, when producing the die model and the core rod model, permalloy (TMB) is used as each base material, and the sleeves 15 and 1 fitted to each base material are used.
The thickness of 6 was 1 mm. Also, the inside diameter of the die model is
22 mm, its axial length was 40 mm, the diameter of the core rod model was 19 mm, and the gap (cavity 9) between these die model and the core rod model was set to 1.5 mm.

【００２４】そして、各コイル１３に２５０ＡＴになる
電流を流し、キャビテイ９の中央部における平均磁束密
度を測定した。この結果、突出部１２の数が２、３、
４、５、６個であるダイスモデルを用いた場合の平均磁
束密度は、それぞれ0.45(T),0.50(T),0.60(T),0.67(T),
0.68(T) となっており、突出部１２の数が４個以上で、
十分大きなラジアル磁界強度が得られることが明らかと
なった。Then, a current of 250 AT was applied to each coil 13 to measure the average magnetic flux density at the center of the cavity 9. As a result, the number of the protrusions 12 is two, three,
The average magnetic flux densities when using 4, 5, and 6 dice models are 0.45 (T), 0.50 (T), 0.60 (T), 0.67 (T),
0.68 (T), and the number of protrusions 12 is 4 or more,
It became clear that a sufficiently large radial magnetic field strength could be obtained.

【００２５】[0025]

【発明の効果】以上、詳細に説明したように、本発明に
係る成形装置によれば、ダイスの外周に設けた突出部を
磁芯として用いることで、キャビテイ内における軸方向
の磁界成分を可及的に低減することが可能になり、円筒
長の長い高性能なラジアル異方性磁石を安定して得るこ
とができる効果がある。また、この突出部を４つ以上設
けて軸心を分散配置することで、コイル発熱を抑制して
成形型の温度上昇を抑えることができ、成形型を水冷構
造とする必要がなくなって構造簡単となるばかりか、直
流の連続印加が可能になって磁性粉末のラジアル配向度
の向上に大きく寄与するものとなる。As described above in detail, according to the molding apparatus according to the present invention, the axial magnetic field component in the cavity can be obtained by using the protrusion provided on the outer periphery of the die as the magnetic core. As a result, it is possible to stably obtain a high-performance radial anisotropic magnet having a long cylindrical length. Also, by providing four or more protruding portions and distributing the shaft center, it is possible to suppress the heat generation of the coil and to suppress the temperature rise of the mold, and it is not necessary to make the mold a water-cooled structure, thereby simplifying the structure. In addition to this, continuous application of direct current becomes possible, which greatly contributes to improvement of the degree of radial orientation of the magnetic powder.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明の第１の実施の形態としての成形装置の
構造と成形型内に発生する磁界の磁路とを示す平面図で
ある。FIG. 1 is a plan view showing a structure of a molding apparatus according to a first embodiment of the present invention and a magnetic path of a magnetic field generated in a molding die.

【図２】第１の実施の形態としての成形装置の構造を示
す断面図である。FIG. 2 is a cross-sectional view illustrating a structure of a molding apparatus according to the first embodiment.

【図３】第１の実施の形態としての成形装置を分解して
示す分解斜視図である。FIG. 3 is an exploded perspective view showing an exploded molding apparatus according to the first embodiment.

【図４】本成形型内における発生磁界の磁路を示す模式
図である。FIG. 4 is a schematic diagram showing a magnetic path of a generated magnetic field in the main mold.

【図５】本成形型内における発生磁界の磁路を示す模式
図である。FIG. 5 is a schematic diagram showing a magnetic path of a generated magnetic field in the main mold.

【図６】本発明の第２の実施の形態としての成形装置の
構造を示す断面図である。FIG. 6 is a cross-sectional view illustrating a structure of a molding apparatus according to a second embodiment of the present invention.

【図７】従来の成形装置の構造を示す断面図である。FIG. 7 is a sectional view showing the structure of a conventional molding apparatus.

【図８】従来の成形装置を分解して示す分解斜視図であ
る。FIG. 8 is an exploded perspective view showing a conventional molding apparatus in an exploded manner.

【図９】従来の成形装置の構造と成形型内に発生する磁
界の磁路とを示す平面図である。FIG. 9 is a plan view showing a structure of a conventional molding apparatus and a magnetic path of a magnetic field generated in a molding die.

【図１０】従来の成形型内における発生磁界の磁路を示
す模式図である。FIG. 10 is a schematic diagram showing a magnetic path of a generated magnetic field in a conventional molding die.

【図１１】従来の成形型内における発生磁界の磁路を示
す模式図である。FIG. 11 is a schematic diagram showing a magnetic path of a generated magnetic field in a conventional molding die.

【符号の説明】[Explanation of symbols]

１ 成形型 ５，６ コアロッド ７，８ パンチ ９ キャビテイ １０ ダイス １１ 本体部 １２ 突出部 １３ コイル １５，１６ スリーブ DESCRIPTION OF SYMBOLS 1 Mold 5, 6 Core rod 7, 8 Punch 9 Cavity 10 Die 11 Main part 12 Projection part 13 Coil 15, 16 Sleeve

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 磁性材料製のダイスと、該ダイスの孔中
心に配置した磁性材料製のコアロッドと、ダイスとコア
ロッドとの間隙に挿入される非磁性材料製の上・下パン
チとからなる成形型を備え、前記成形型内にコイルによ
りラジアル磁界を形成し、このラジアル磁界内で成形型
のキャビテイ内に入れた磁性粉末をラジアル配向させて
圧縮成形する円筒状ラジアル異方性磁石の成形装置にお
いて、前記成形型のダイスの外周に、その周方向に等配
して少なくとも４つの突出部を放射状に設け、前記各突
出部に前記コイルを巻装して、ダイス中心に同磁極を指
向させるようにしたことを特徴とする円筒状ラジアル異
方性磁石の成形装置。1. A molding comprising a die made of a magnetic material, a core rod made of a magnetic material disposed at the center of a hole of the die, and upper and lower punches made of a non-magnetic material inserted into a gap between the die and the core rod. A molding device for a cylindrical radial anisotropic magnet, comprising a mold, forming a radial magnetic field by a coil in the molding die, and radially orienting and compressing the magnetic powder placed in the cavity of the molding die in the radial magnetic field. , At least four protrusions are radially provided on the outer periphery of the die of the molding die at equal intervals in the circumferential direction, and the coils are wound around the respective protrusions to direct the same magnetic pole toward the center of the die. A molding device for a cylindrical radial anisotropic magnet, characterized in that: 【請求項２】 突出部の軸方向長さを、成形型のキャビ
テイの軸方向長さの少なくとも９０％に設定したことを
特徴とする請求項１に記載の円筒状ラジアル異方性磁石
の成形装置。2. The molding of the cylindrical radial anisotropic magnet according to claim 1, wherein the axial length of the projection is set to at least 90% of the axial length of the cavity of the mold. apparatus.
JP32463196A 1996-10-15 1996-11-20 Cylindrical radial anisotropic magnet forming device Expired - Fee Related JP3774876B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP32463196A JP3774876B2 (en) 1996-10-15 1996-11-20 Cylindrical radial anisotropic magnet forming device

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP29340296 1996-10-15
JP8-293402 1996-10-15
JP32463196A JP3774876B2 (en) 1996-10-15 1996-11-20 Cylindrical radial anisotropic magnet forming device

Publications (2)

Publication Number Publication Date
JPH10177928A true JPH10177928A (en) 1998-06-30
JP3774876B2 JP3774876B2 (en) 2006-05-17

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ID=26559395

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Country Link
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US6529107B2 (en) 1999-12-16 2003-03-04 Hitachi Metals Ltd. Speaker comprising ring magnet
WO2005104337A1 (en) * 2004-04-20 2005-11-03 Aichi Steel Corporation Anisotropic bond magnet for four-magnetic-pole motor, motor using the same, device for orientation processing of anisotropic bond magnet for four-magnetic-pole motor
WO2009001801A1 (en) * 2007-06-28 2008-12-31 Hitachi Metals, Ltd. R-tm-b radial anisotropic ring magnet, process for production of the same, metal mold for producing the same, and rotor for brushless motor
CN110568061A (en) * 2019-09-17 2019-12-13 常州捷锐试验检测有限公司 magnetic powder detection method for circumferential defects of inner wall of hole

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6529107B2 (en) 1999-12-16 2003-03-04 Hitachi Metals Ltd. Speaker comprising ring magnet
WO2005104337A1 (en) * 2004-04-20 2005-11-03 Aichi Steel Corporation Anisotropic bond magnet for four-magnetic-pole motor, motor using the same, device for orientation processing of anisotropic bond magnet for four-magnetic-pole motor
US7592889B2 (en) 2004-04-20 2009-09-22 Aichi Steel Corporation Anisotropic bond magnet for four-magnetic-pole motor, motor using the same, device for orientation processing of anisotropic bond magnet for four-magnetic-pole motor
US7750776B2 (en) 2004-04-20 2010-07-06 Aichi Steel Corporation Anisotropic bonded magnet for use in a 4-pole motor, a motor employing that magnet, and an alignment process apparatus for the anisotropic bonded magnet for use in a 4-pole motor
WO2009001801A1 (en) * 2007-06-28 2008-12-31 Hitachi Metals, Ltd. R-tm-b radial anisotropic ring magnet, process for production of the same, metal mold for producing the same, and rotor for brushless motor
US20100181859A1 (en) * 2007-06-28 2010-07-22 Hitachi Metals, Ltd. Radially anisotropic ring r-tm-b magnet, its production method, die for producing it, and rotor for brushless motor
JP5267459B2 (en) * 2007-06-28 2013-08-21 日立金属株式会社 R-TM-B radial anisotropy ring magnet, manufacturing method thereof, mold for manufacturing the same, and rotor for brushless motor
US8937419B2 (en) 2007-06-28 2015-01-20 Hitachi Metals, Ltd. Radially anisotropic ring R-TM-B magnet, its production method, die for producing it, and rotor for brushless motor
CN110568061A (en) * 2019-09-17 2019-12-13 常州捷锐试验检测有限公司 magnetic powder detection method for circumferential defects of inner wall of hole

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