JPH0273612A - Manufacture of large-sized ferrite core - Google Patents
Manufacture of large-sized ferrite coreInfo
- Publication number
- JPH0273612A JPH0273612A JP63225443A JP22544388A JPH0273612A JP H0273612 A JPH0273612 A JP H0273612A JP 63225443 A JP63225443 A JP 63225443A JP 22544388 A JP22544388 A JP 22544388A JP H0273612 A JPH0273612 A JP H0273612A
- Authority
- JP
- Japan
- Prior art keywords
- molded body
- ferrite
- sintering
- heat
- resistant
- 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.)
- Pending
Links
- 229910000859 α-Fe Inorganic materials 0.000 title claims abstract description 63
- 238000004519 manufacturing process Methods 0.000 title claims description 16
- 238000005245 sintering Methods 0.000 claims abstract description 28
- 230000008602 contraction Effects 0.000 claims abstract description 7
- 238000000034 method Methods 0.000 claims description 19
- 238000005336 cracking Methods 0.000 abstract description 6
- 239000000843 powder Substances 0.000 description 8
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 4
- 238000000465 moulding Methods 0.000 description 4
- 238000009694 cold isostatic pressing Methods 0.000 description 3
- 239000005751 Copper oxide Substances 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 229910000431 copper oxide Inorganic materials 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 229910000480 nickel oxide Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229910018605 Ni—Zn Inorganic materials 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 229910001035 Soft ferrite Inorganic materials 0.000 description 1
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 1
- 229910007565 Zn—Cu Inorganic materials 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000007723 die pressing method Methods 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003574 free electron Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 1
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 230000005469 synchrotron radiation Effects 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Landscapes
- Magnetic Ceramics (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は大型フェライトコアの製造方法に関し、特に焼
結中に割れやそりが入らない大型フェライトコアの製造
方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a large ferrite core, and more particularly to a method for manufacturing a large ferrite core that does not cause cracks or warpage during sintering.
フェライトはＦｅ、０．に各種の金属酸化物を添加して
なるものであり、永久磁石や軟磁性材料として広く使用
されている。特に、磁心として用いる場合、良好な軟磁
性を有するという理由でＮｉ−Ｚｎ系やＭｎ−Ｚｎ系の
フェライトが使用されている。フェライトは一般に、Ｆ
ｅ２Ｌ粉末に各種金属酸化物あるいは金属炭酸塩等の粉
末を配合し、金型プレス、冷間静水圧プレス（ＣＩＰ）
等により成形した後、焼結することにより製造すること
ができる。Ferrite is Fe, 0. It is made by adding various metal oxides to magnets, and is widely used as permanent magnets and soft magnetic materials. In particular, when used as a magnetic core, Ni-Zn-based and Mn-Zn-based ferrites are used because they have good soft magnetism. Ferrite is generally F
Mix e2L powder with powders such as various metal oxides or metal carbonates, and perform mold pressing and cold isostatic pressing (CIP).
It can be manufactured by molding by a method such as the above method and then sintering.
最近、自由電子レーザーやシンクロトロン放射光装置の
加速器等にソフトフェライトの大型コアを使用すること
が試みられている。この場合、扇形状のフェライトコア
片を作成し、それらを一体的に接合すれば、簡単に大型
コアとすることができる。ところが、コア片を接合すれ
ばギャップが形成されることになり、そこから磁束が漏
洩したりして、加速器用のコアとしては好ましくない。Recently, attempts have been made to use large soft ferrite cores in free electron lasers, accelerators for synchrotron radiation devices, and the like. In this case, by creating fan-shaped ferrite core pieces and joining them together, a large core can be easily obtained. However, if the core pieces are joined together, a gap will be formed, from which magnetic flux may leak, making it undesirable as a core for an accelerator.
そこで大型コアを一体的に形成することが望まれている
。Therefore, it is desired to integrally form a large core.
〔発明が解決しようとする課題〕
しかしながら、フェライトは焼結により約２０％近く収
縮するので、大型フェライトコアの場合、平坦な土台と
成形体の間にすべりが生じ、割れやそりの原因となるこ
とがわかった。[Problem to be solved by the invention] However, since ferrite shrinks by about 20% during sintering, in the case of large ferrite cores, slipping occurs between the flat base and the molded body, causing cracks and warping. I understand.
従って本発明の目的は焼結中に割れやそりを生ずること
なく大型フェライトコアを製造する方法を提供すること
である。It is therefore an object of the present invention to provide a method for manufacturing large ferrite cores without cracking or warping during sintering.
上記目的に汲み鋭意研究の結果、本発明者は焼結中に成
形体と土台との間に直接すべりが生じないようにその間
に回転体を配置し、かつ成形体の収縮に応じて回転体が
回転したときに近隣の回転体が妨害し合わないように、
回転体間に十分な間隔を設けておくことにより、割れや
そりのない大型フェライトコアを製造することができる
ことを発見し、また厚手の大型フェライトコアの場合、
フェライト成形体と球面接触する媒体を介在させること
により、フェライト成形体がその媒体上をスムーズにす
べることができることを発見し、本発明に想到した。As a result of intensive research with the above purpose in mind, the present inventors placed a rotating body between the molded body and the base to prevent direct slippage between the molded body and the base during sintering, and the rotating body To prevent neighboring rotating bodies from interfering with each other when the rotates,
We discovered that by providing sufficient space between rotating bodies, it is possible to manufacture large ferrite cores without cracks or warpage, and in the case of thick large ferrite cores,
The inventors have discovered that by interposing a medium that makes spherical contact with the ferrite molded body, the ferrite molded body can smoothly slide on the medium, and have conceived the present invention.
すなわち、本発明の大型フェライトコアの第一の製造方
法は、平坦な土台上に多数の耐熱性回転体を介してフェ
ライト成形体を静置し、前記フェライト成形体を焼結す
るものであって、焼結による前記フェライト成形体の収
縮に応じて前記耐熱性回転体が自由に回転できるように
、前記回転体間に十分な間隔を存在させることを特徴と
する。That is, the first method for producing a large ferrite core of the present invention is to place a ferrite molded body on a flat base via a large number of heat-resistant rotating bodies, and then sinter the ferrite molded body. A sufficient space is provided between the rotary bodies so that the heat-resistant rotary bodies can freely rotate in response to contraction of the ferrite molded body due to sintering.
本発明の第二の製造方法は、平坦な土台上に多数の耐熱
性球体を介してフェライト成形体を静置し、前記フェラ
イト成形体を焼結することにより厚手の大型フェライト
コアを製造する方法であって、焼結による前記フェライ
ト成形体の収縮に応じて前記耐熱性球体上を前記フェラ
イト成形体がすべることを特徴とする。A second manufacturing method of the present invention is a method of manufacturing a thick large ferrite core by placing a ferrite molded body on a flat base via a large number of heat-resistant spheres and sintering the ferrite molded body. The ferrite molded body is characterized in that the ferrite molded body slides on the heat-resistant sphere in response to contraction of the ferrite molded body due to sintering.
本発明の第三の製造方法は、多数の球面状突起を有する
平坦な耐熱性土台上にフェライト成形体を静置し、前記
フェライト成形体を焼結することにより厚手の大型フェ
ライトコアを製造する方法であって、焼結による前記フ
ェライト成形体の収縮に応じて前記球面状突起上を前記
フェライト成形体がすべることを特徴とする。A third manufacturing method of the present invention is to manufacture a thick large ferrite core by placing a ferrite molded body still on a flat heat-resistant base having a large number of spherical protrusions and sintering the ferrite molded body. The method is characterized in that the ferrite molded body slides on the spherical protrusion in response to contraction of the ferrite molded body due to sintering.
第１図に示すように、フェライトコア用の成形体Ｉは回
転体２を介して土台３上に静置されるが、各回転体２の
間隔は十分にとられている。このような状態で焼結を行
うと成形体１は収縮するが、それに応じて回転体２は成
形体１と土台３との間で回転しながら、内側に移動する
。すなわち回転体２はころの作用をする。これにより成
形体１と土台３との間のすべりは完全に防止され、それ
に基づく割れやそりの問題がなくなる。As shown in FIG. 1, a molded body I for a ferrite core is placed on a base 3 via rotating bodies 2, with sufficient intervals between the rotating bodies 2. When sintering is performed in such a state, the molded body 1 contracts, and the rotating body 2 rotates between the molded body 1 and the base 3 and moves inward accordingly. That is, the rotating body 2 acts as a roller. This completely prevents slippage between the molded body 1 and the base 3, and eliminates the problems of cracking and warping caused by this.
ところが、回転体２の密度が高すぎると、回転体２が内
側に移動中前方の回転体２により進路を妨げられ、結局
第３図に示すように乗り上げる格構となる。こうなると
成形体ｌは変形し、そのまま焼結するので局部的に曲が
ったりそったりした形状となる。またこれにより焼結割
れが生ずることもある。However, if the density of the rotating body 2 is too high, the rotating body 2 will be obstructed in its path by the rotating body 2 in front of it while moving inward, and will end up running over as shown in FIG. In this case, the molded body l is deformed and sintered as it is, resulting in a locally bent or warped shape. This may also cause sintering cracks.
一方厚手の大型フェライトコアの場合、フェライト成形
体に接触する球体又は球面状突起の密度が高くないと、
点接触により成形体にへこみができるので、密度を高く
する。この場合、成形体と球体又は球面状突起とは球面
接触であるので、成形体の重みにもかかわらずスムーズ
にすべることができる。On the other hand, in the case of a thick large ferrite core, if the density of the spheres or spherical protrusions that contact the ferrite molded body is not high,
Point contact creates dents in the molded body, so the density is increased. In this case, since the molded body and the sphere or spherical protrusion are in spherical contact, the molded body can slide smoothly despite the weight of the molded body.
本発明の大型フェライトコアは、各種のフェライト材料
により形成することができるが、良好な軟磁性を有する
という意味でＮ１Ｊｎ系フエライトにより形成するのが
好ましい。特に酸化第二鉄（Ｆｅ、０３）に酸化ニッケ
ル（ＮｉＯ） １２〜３０モル％、酸化亜鉛（ＺｎＯ）
１５〜３５モル％、酸化銅（Ｃｕｂ） ２〜１０モ
ル％を配合してなるものが好ましい。Although the large ferrite core of the present invention can be formed from various ferrite materials, it is preferably formed from N1Jn ferrite in the sense that it has good soft magnetic properties. In particular, ferric oxide (Fe, 03), nickel oxide (NiO) 12-30 mol%, zinc oxide (ZnO)
It is preferable to mix 15 to 35 mol % of copper oxide (Cub) and 2 to 10 mol % of copper oxide (Cub).
成形体は、上記成分の粉末を混合、仮焼し、粉砕後造粒
し、１５０〜３５０μｍ程度の粒度に分級したものを用
いて形成する。成形は金型プレスにより行うことができ
るが、大型コア成形体全体を均一な密度にするという観
点から冷間静水圧プレス（ＣＩＰ）により行うのが好ま
しい。金型プレスの場合、０，５ｔ／ｃｆｆ１以上の圧
力で行い、ＣＩＰの場合も０．５ｔ／ｃｆｆ１以上の圧
力で行う。The molded body is formed by mixing powders of the above components, calcining them, pulverizing them, granulating them, and classifying them into particle sizes of about 150 to 350 μm. Although the molding can be performed by die pressing, it is preferable to perform the molding by cold isostatic pressing (CIP) from the viewpoint of making the entire large core molded body have a uniform density. In the case of mold press, it is performed at a pressure of 0.5 t/cff1 or more, and in the case of CIP, it is performed at a pressure of 0.5 t/cff1 or more.
第１図に示すように、成形体ｌを、回転体２を介して土
台３上に静置する。回転体２は焼結中度性しないように
十分な耐熱性を有する必要があり、かつ焼結中成形体と
反応しないものである必要がある。この意味でセラミッ
ク製とするのが好ましく、特にアルミナ（ＡＩＪ：＋）
ＩＪとするのが好ましい。As shown in FIG. 1, a molded body 1 is placed on a base 3 via a rotating body 2. The rotating body 2 needs to have sufficient heat resistance so as not to cause intermediate sintering, and needs to not react with the compact during sintering. In this sense, it is preferable to use ceramic, especially alumina (AIJ:+).
It is preferable to use IJ.
回転体２はまた、任意の方向へ自由に回転できるという
意味で球体であるのが好ましい。球体の直径は成形体の
重量により異なるが、一般に焼結後の厚さが１７２イン
チ（１２，７ｍｍ）以下の場合１〜１０ｍ１Ｔｌφ程度
であればよく、焼結後の厚さが１７２インチ（１２，７
ｍｍ） 〜１インチ（２５，４ｍｍ）の場合１５〜２０
ｍｍφ程度であればよい。球体はまた同じ大きさである
必要はなく、大直径の球体と小直径の球体とを組合せて
用いることにより、ころがりを−層良好にすることがで
きる。この場合大直径の球体だけが成形体と接触する。The rotating body 2 is also preferably spherical in the sense that it can freely rotate in any direction. The diameter of the sphere varies depending on the weight of the molded body, but in general, if the thickness after sintering is 172 inches (12.7 mm) or less, it may be about 1 to 10 m1Tlφ; ,7
mm) ~15~20 for 1 inch (25,4mm)
It suffices if it is about mmφ. The spheres also do not have to be of the same size; a combination of large and small diameter spheres can be used to improve rolling. In this case only the large diameter spheres come into contact with the shaped body.
例えば１０ｍｍφの球体と５ｍｍφの球体を組み合わせ
て使用することができる。焼結により成形体は約２０％
近く収縮し、第２図に示すように、回転体（球体）２間
の間隔は狭くなる。成形体の収縮率から考えて、理論的
には回転体２の平面占有率（平面上を回転体２が占める
割合で最密充填の場合を１００％とする）は約８０％と
すればよいわけであるが、実用的には回転体２の配置の
局所的不均一さや回転の不均一さの可能性等を考慮して
、平面占有率は２０〜８０％程度とする。２０％未満で
あると、個々の回転体２にかかる成形体１の重量が大き
くなりすぎ、成形体１に凹みが生じる。また８０％を超
えると隣接する回転体２が回転を妨害し合って、第３図
に示すように回転体２が乗り上げる現象が生ずるおそれ
がある。For example, a 10 mmφ sphere and a 5 mmφ sphere can be used in combination. Approximately 20% of the compact is reduced by sintering.
It will soon contract, and as shown in FIG. 2, the distance between the rotating bodies (spherical bodies) 2 will become narrower. Considering the shrinkage rate of the molded body, theoretically, the plane occupancy rate of the rotating body 2 (the proportion that the rotating body 2 occupies on the plane, in the case of close packing is assumed to be 100%) should be about 80%. However, in practical terms, the plane occupancy rate is set to about 20 to 80%, taking into consideration the possibility of local non-uniformity in the arrangement of the rotating body 2 and non-uniform rotation. If it is less than 20%, the weight of the molded body 1 applied to each rotating body 2 becomes too large, and a dent occurs in the molded body 1. If it exceeds 80%, there is a risk that adjacent rotating bodies 2 will interfere with each other's rotation, causing a phenomenon in which the rotating bodies 2 ride on each other as shown in FIG.
この平面占有率の選定は、成形体の厚みによっである程
度決まるものであり、成形体が厚い場合には平面占有率
を大きくし、成形体が薄い場合には平面占有率を小さく
することができる。The selection of this plane occupancy rate is determined to some extent by the thickness of the molded body; if the molded body is thick, the plane occupancy rate may be increased, and if the molded body is thin, the plane occupancy rate may be decreased. can.
なお回転体２は均一に配置する必要があり、そのために
は土台３上に焼結温度により焼失する粘着剤や結合剤等
を塗布する等して、固定しておけばよい。Note that the rotating bodies 2 need to be arranged uniformly, and for this purpose, they may be fixed by applying an adhesive, a binder, or the like that is burnt off at the sintering temperature onto the base 3.
一方厚手の大型フェライトコアの場合、成形体と球面接
触する媒体を用い、成形体をスムーズにすべらせるのが
好ましい。例えば球体を用いる場合、成形体の重みによ
り前の球体に乗り上げるおそれはない。また球面状突起
を多数有する平面体を用いる場合も同様に、球面接触に
よりスムーズなすべりが保証される。いずれの場合も、
平面占有率としては１００％まで可能である。On the other hand, in the case of a thick large ferrite core, it is preferable to use a medium that makes spherical contact with the molded body to allow the molded body to slide smoothly. For example, when using a sphere, there is no risk of the molded body riding on the previous sphere due to its weight. Similarly, when using a planar body having a large number of spherical protrusions, smooth sliding is ensured by the spherical contact. In either case,
The plane occupancy rate can be up to 100%.
焼結は大型熱処理炉中で１０５０〜１２００℃で２〜１
０時間行う。焼結後は焼結体を研削加工し、所定のサイ
ズにそろえる。Sintering is performed in a large heat treatment furnace at 1050-1200℃ for 2 to 1
Do it for 0 hours. After sintering, the sintered body is ground to the desired size.
このようにして外径５００ ｍｍ以上、特に６５０ ｍ
ｍ以上で、厚さ４〜６０ｍｍの大型フェライトコアを製
造することができる。なお厚さが４ｍｍ未満となると割
れやそりが発生しやすくなり、製造歩留まりが低下する
。大型フェライトコアの内径はとくに制限ないが、例え
ば外径が６５０ ｍｍの場合３５０ ｍｍ程度であれば
よい。In this way, with an outer diameter of 500 mm or more, especially 650 m
m or more, a large ferrite core with a thickness of 4 to 60 mm can be manufactured. Note that if the thickness is less than 4 mm, cracks and warpage are likely to occur, resulting in a decrease in manufacturing yield. The inner diameter of the large ferrite core is not particularly limited, but for example, if the outer diameter is 650 mm, it may be about 350 mm.
このようにして得られた大型フェライトコアは、特にＮ
ｉ−Ｚｎ−Ｃｕ系フェライトからなる場合、３０００〜
４３００ＫＧと高い飽和磁束密度（ＢＳ）と、０．１〜
１．５０ｅと低い保磁力（Ｈａ）と、８０Ｊ／ｍ’ｋＧ
以下のコアロス（エネルギー損失）とを有する。The large ferrite core obtained in this way is particularly
When made of i-Zn-Cu ferrite, 3000~
High saturation magnetic flux density (BS) of 4300KG and 0.1~
Low coercive force (Ha) of 1.50e and 80J/m'kG
It has the following core loss (energy loss).
一般に、コアロスはコアにかかるパルスの周波数ととも
に増大し、また厚さとともに増大する。Generally, core loss increases with the frequency of pulses applied to the core, and also increases with thickness.
従って、コアロスによる熱を放冷するとともに、コアロ
ス自身を低下させるために、大型フェライトコアはでき
るだけ薄い方が好ましい。しかし製造歩留まりの観点か
ら、５００ ｍｍφ以上の外径の場合、１７４インチ（
６，４ｍｍ）以下とすることは困難である。Therefore, it is preferable that the large ferrite core be as thin as possible in order to dissipate the heat caused by the core loss and to reduce the core loss itself. However, from the viewpoint of manufacturing yield, in the case of an outer diameter of 500 mmφ or more, 174 inches (
6.4 mm) or less is difficult.
実施例Ｉ
Ｎ＋Ｑ粉末２５．０モル％、ＸｎＯ粉末２１．０モル％
、ＣｕＯ粉末４．５モル％、残部Ｆｅ２Ｏ：＋粉末を混
合し、８００℃で仮焼し、粉砕後スプレードライ法で造
粒し、１５０〜３５０μｍの粒度に分級した。Example I N+Q powder 25.0 mol%, XnO powder 21.0 mol%
, 4.5 mol % of CuO powder, and the remainder Fe2O:+ powder were mixed, calcined at 800°C, pulverized, granulated by a spray drying method, and classified to a particle size of 150 to 350 μm.
得られた厚料粉末にポリビニルアルコールバインダー１
％を添加し、金型ブレスにより０．７５ｔ／ｃ＋＋１の
成形圧で外径８２５ ｍｍ、内径４１０ ｍｍ、厚さ３
８ｍｍの環状成形体を作成した。この成形体を、直径１
０ｍｍのｈｌ 、０．球体を介してムライト製土台板上
にほぼ均一に配置した。Polyvinyl alcohol binder 1 is added to the obtained thick powder.
%, and molding pressure of 0.75t/c++1 with a mold press to form an outer diameter of 825 mm, an inner diameter of 410 mm, and a thickness of 3.
An 8 mm annular molded body was created. This molded body has a diameter of 1
0mm hl, 0. The spheres were placed almost uniformly on the mullite base plate.
次に大型熱処理炉中で１１００℃で５時間焼結を行い、
外径６６０ ｍｍ、内径３２８ ｍｍ、厚さ３０．４ｍ
ｍの焼結体を得た。得られた焼結体には割れやそりは全
くなかった。このようにして得られた焼結体を研削加工
することにより、外径６５０ ｍｍ、内径３５０ ｍｍ
、厚さ１２．８ｍｍの環状大型フェライトコアを得るこ
とができた。Next, sintering was performed at 1100°C for 5 hours in a large heat treatment furnace.
Outer diameter 660 mm, inner diameter 328 mm, thickness 30.4 m
A sintered body of m was obtained. The obtained sintered body had no cracks or warpage. By grinding the sintered body thus obtained, it has an outer diameter of 650 mm and an inner diameter of 350 mm.
, a large annular ferrite core with a thickness of 12.8 mm could be obtained.
〔発明の効果］
以上説明した通り、本発明の方法は、耐熱回転体を介し
て成形体を土台上に静置し焼結するので、焼結により成
形体が収縮しても土台との間にずりが起こることはなく
、従って割れやそりを防止することができる。また厚手
の大型フェライトコアの場合は球面接触する媒体を用い
て成形体をすべらせるので、同様に割れやそりのおそれ
がなく、さらに接触によるへこみも最小におさえること
ができる。このため、本発明の方法によれば大型フェラ
イトコアを歩留まりよく製造することができる。[Effects of the Invention] As explained above, in the method of the present invention, the molded body is placed on the base via the heat-resistant rotating body and sintered, so even if the molded body shrinks due to sintering, there is no gap between the molded body and the base. No shearing occurs, and therefore cracking and warping can be prevented. In addition, in the case of a thick large ferrite core, since the molded body is slid using a medium that contacts the spherical surfaces, there is no fear of cracking or warping, and furthermore, dents due to contact can be minimized. Therefore, according to the method of the present invention, large ferrite cores can be manufactured with a high yield.
第１図はフェライト成形体が耐熱回転体を介して土台上
に静置されている状態を示す断面図であり、
第２図は焼結によりフェライト成形体が収縮している状
態を示す断面図であり、
第３図は耐熱回転体が乗り上げることにより成形体（焼
結体）が変形したことを示す断面図である。
１・・・フェライト成形体
２・・・耐熱回転体
３・・・土台
第１図
嘉２図Fig. 1 is a sectional view showing a state in which the ferrite molded body is placed on a base via a heat-resistant rotating body, and Fig. 2 is a sectional view showing the state in which the ferrite molded body is contracted due to sintering. FIG. 3 is a cross-sectional view showing that the molded body (sintered body) is deformed due to the heat-resistant rotating body running over it. 1... Ferrite molded body 2... Heat resistant rotating body 3... Base Figure 1 Figure 2
Claims (5)
ライト成形体を静置し、前記フェライト成形体を焼結す
ることにより大型フェライトコアを製造する方法であっ
て、焼結による前記フェライト成形体の収縮に応じて前
記耐熱性回転体が自由に回転できるように、前記回転体
間に十分な間隔を存在させることを特徴とする方法。(1) A method for manufacturing a large ferrite core by placing a ferrite molded body on a flat base via a number of heat-resistant rotating bodies and sintering the ferrite molded body, the method comprising: A method characterized in that a sufficient distance is provided between the rotary bodies so that the heat-resistant rotary bodies can freely rotate in response to contraction of the ferrite molded body.
体がＡｌ＿２Ｏ＿３製球体であり、かつ前記球体の平面
占有率が２０〜８０％であることを特徴とする方法。(2) The method according to claim 1, wherein the heat-resistant rotating body is a sphere made of Al_2O_3, and the surface area of the sphere is 20 to 80%.
イト成形体を静置し、前記フェライト成形体を焼結する
ことにより厚手の大型フェライトコアを製造する方法で
あって、焼結による前記フェライト成形体の収縮に応じ
て前記耐熱性球体上を前記フェライト成形体がすべるこ
とを特徴とする方法。(3) A method for manufacturing a thick large ferrite core by placing a ferrite molded body on a flat base via a large number of heat-resistant spheres and sintering the ferrite molded body, the ferrite core being produced by sintering. A method characterized in that the ferrite molded body slides on the heat-resistant sphere in response to contraction of the ferrite molded body.
体がＡｌ＿２Ｏ＿３製球体であることを特徴とする方法
。(4) The method according to claim 3, wherein the heat-resistant rotating body is a sphere made of Al_2O_3.
フェライト成形体を静置し、前記フェライト成形体を焼
結することにより厚手の大型フェライトコアを製造する
方法であって、焼結による前記フェライト成形体の収縮
に応じて前記球面状突起上を前記フェライト成形体がす
べることを特徴とする方法。(5) A method for manufacturing a thick large ferrite core by placing a ferrite molded body on a flat heat-resistant base having a large number of spherical projections and sintering the ferrite molded body, the method comprising: A method characterized in that the ferrite molded body slides on the spherical protrusion in accordance with the contraction of the ferrite molded body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63225443A JPH0273612A (en) | 1988-09-08 | 1988-09-08 | Manufacture of large-sized ferrite core |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63225443A JPH0273612A (en) | 1988-09-08 | 1988-09-08 | Manufacture of large-sized ferrite core |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0273612A true JPH0273612A (en) | 1990-03-13 |
Family
ID=16829442
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63225443A Pending JPH0273612A (en) | 1988-09-08 | 1988-09-08 | Manufacture of large-sized ferrite core |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0273612A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007136483A (en) * | 2005-11-16 | 2007-06-07 | Denso Corp | Laser beam machining device |
| US8184381B2 (en) | 2006-05-26 | 2012-05-22 | Ricoh Company, Ltd. | Lens driving-control device and imaging apparatus including the lens driving-control device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61195902A (en) * | 1985-02-25 | 1986-08-30 | Matsushita Electric Works Ltd | Sintering method of rare earth magnet |
| JPS63202011A (en) * | 1987-02-17 | 1988-08-22 | Nippon Ferrite Ltd | Manufacture of cylindrical core |
-
1988
- 1988-09-08 JP JP63225443A patent/JPH0273612A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61195902A (en) * | 1985-02-25 | 1986-08-30 | Matsushita Electric Works Ltd | Sintering method of rare earth magnet |
| JPS63202011A (en) * | 1987-02-17 | 1988-08-22 | Nippon Ferrite Ltd | Manufacture of cylindrical core |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007136483A (en) * | 2005-11-16 | 2007-06-07 | Denso Corp | Laser beam machining device |
| US8184381B2 (en) | 2006-05-26 | 2012-05-22 | Ricoh Company, Ltd. | Lens driving-control device and imaging apparatus including the lens driving-control device |
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