JP3408587B2 - Method of manufacturing soft ferrite E-type core - Google Patents
Method of manufacturing soft ferrite E-type coreInfo
- Publication number
- JP3408587B2 JP3408587B2 JP20326293A JP20326293A JP3408587B2 JP 3408587 B2 JP3408587 B2 JP 3408587B2 JP 20326293 A JP20326293 A JP 20326293A JP 20326293 A JP20326293 A JP 20326293A JP 3408587 B2 JP3408587 B2 JP 3408587B2
- Authority
- JP
- Japan
- Prior art keywords
- soft ferrite
- leg
- molded body
- type core
- core
- 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 - Fee Related
Links
Landscapes
- Magnetic Ceramics (AREA)
- Soft Magnetic Materials (AREA)
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、高周波トランスやコイ
ル等に広く用いられているＥ型ソフトフェライトコアの
製造方法に関するものである。
【０００２】
【従来の技術】従来、Ｅ型のフェライトコアを製造する
方法としては、所定の組成のフェライト原料を混合、仮
焼、粉砕した後、更にこれにＰＶＡ等の有機物系のバイ
ンダーを加えると共に造粒することによって得た顆粒を
金型に充填して圧縮成形し、引続いて温度および雰囲気
が制御された炉中で焼成する方法が一般的である。
【０００３】
【発明が解決しようとする課題】しかし従来の焼成方法
では、フェライトコアの寸法が大型の場合、焼成工程の
初期の約 500℃までの温度範囲で起こるバインダーとし
て加えられているＰＶＡ等の成形体からの逸散・燃焼反
応（脱バインダー反応と称する）に際し、特に断面積の
大きい中脚部において成形体の表面層と中心層での温度
分布の差異のために異なる脱バインダー挙動となり、発
熱反応であるバインダーの燃焼反応の場所的・時間的遅
れが生じる結果、成形体内に大きな温度分布の不均一が
生じ、図２に示すような割れ欠陥が頻発することが多か
った。
【０００４】本発明は、比較的大型のＥ型コアにおける
成形体焼成時のこのような割れ欠陥を、磁気特性に悪影
響を与えることなく防止できるソフトフェライトＥ型コ
アの製造方法を提供することを目的とするものである。
【０００５】
【課題を解決するための手段】本発明は、調整した所定
の組成のフェライト原料に有機物系のバインダーを加
え、圧縮成形して成形体を作成し、該成形体を焼成し、
ソフトフェライトＥ型コアを製造するに際して、前記成
形体の中脚部に脚長手方向一端面から脚長手方向に直径
が１mm以下の所定深さの細孔を設けて焼成することを特
徴とするソフトフェライトＥ型コアの製造方法である。
【０００６】
【作用】本発明は、金型による圧縮成形時または得られ
た成形体に対して穿孔により、成形体の中脚部に細孔を
形成することに大きな特徴があり、このことにより脱バ
インダー時、中脚中央部からのバインダーの除去が表面
に比較して遅れなく進むようになり、成形体内の温度分
布が大幅に改善されることを通じて割れ発生が抑制でき
るようになった。
【０００７】形成する細孔は直径１mm以下で充分であ
り、その深さも中脚長の１／２長程度でよい。
【０００８】
【実施例】SiO2−CaO −Nb2O5 −Sb2O3 を添加物とする
低損失MnZnフェライトを用い、通常の方法でＥＲ49Ｍの
大型コアを 200個成形した。 100個のコアについては、
成形体の中脚中央に図１に示すように直径が 0.8mmで深
さが中脚長さの１／２の細孔をドリル穿孔した後焼成し
た。ドリル穿孔のないコアを比較材とした。
【０００９】焼成時脱バインダー範囲の昇温速度は 130
℃／Hrであった。得られたコアについて割れ欠陥の発生
頻度は、本発明例の場合０％、比較例の場合８％であ
り、本発明の方法によって大幅に改善された。磁気特性
に関しては100kHz、200mT 、 100℃のコアロス値で 390
±10mw／cm3と両者で全く差異がなかった。
【００１０】
【発明の効果】成形体の中脚部において脚の長手方向に
細孔を設けて焼成することにより、従来、特に大型コア
で問題となっていた焼成時の脱バインダー温度域で発生
頻度が高かった割れの発生を効果的に抑制できた。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an E-type soft ferrite core widely used for high-frequency transformers and coils.
It relates to a manufacturing method. Conventionally, as a method for producing an E-type ferrite core, a ferrite raw material having a predetermined composition is mixed, calcined and pulverized, and then an organic binder such as PVA is added thereto. granulated granules were obtained by the compression molding was filled in a mold, how to baking in an oven where temperature and atmosphere is controlled subsequently is common with. However, in the conventional sintering method, when the size of the ferrite core is large, PVA or the like added as a binder which occurs in a temperature range up to about 500 ° C. in the initial stage of the sintering step. During the escaping and burning reaction from the molded body (referred to as debinding reaction), the debinding behavior is different due to the difference in temperature distribution between the surface layer and the center layer of the molded body , especially in the middle leg with a large cross-sectional area. as a result of the location and temporal delay of the combustion reaction of the exothermic reaction the binder occurs, nonuniformity of large temperature distribution in the molded body is produced, cracking defects as shown in FIG. 2 was often frequent. The present invention relates to a relatively large E-shaped core.
A soft ferrite E-type core that can prevent such cracking defects during firing of a compact without adversely affecting magnetic properties.
It is intended to provide a method for producing the same. SUMMARY OF THE INVENTION The present invention provides an adjusted predetermined
Organic binder is added to ferrite raw material of composition
For example, compression molding is performed to form a molded body, and the molded body is fired.
In the production of soft ferrite E-shaped core, the formed
A method for producing a soft ferrite E-type core, comprising providing a fine hole having a predetermined depth of 1 mm or less in a longitudinal direction of a leg from one end surface in a longitudinal direction of a leg in a middle leg portion of the shape and firing. [0006] DETAILED DESCRIPTION OF THE INVENTION The present invention, by piercing against the time of compression molding using a mold or the resulting molded product, there is a great feature to form pores in the center leg of the molded body, by this during debinding, binder removal from the middle leg center portion becomes proceed without delay compared to the surface, generating cracks through the temperature distribution of the molded body is significantly improved it can now be prevented. It is sufficient that the diameter of the formed pore is 1 mm or less, and the depth thereof is about half the length of the middle leg. [0008] [Example] Using low loss MnZn ferrite and the SiO 2 -CaO -Nb 2 O 5 -Sb 2 O 3 additive was 200 forming a large-sized core ER49M in the usual way. For 100 cores,
In the center of the center leg of the formed body, as shown in FIG. 1, a hole having a diameter of 0.8 mm and a depth of 1/2 of the length of the center leg was drilled and fired. A core without drilling was used as a comparative material. The rate of temperature rise in the binder removal range during firing is 130
° C / Hr. The frequency of occurrence of crack defects in the obtained core was 0% in the case of the present invention and 8% in the case of the comparative example, which was greatly improved by the method of the present invention. Regarding magnetic properties, a core loss value of 390 at 100kHz, 200mT, 100 ℃
± 10 mw / cm 3 and no difference between them. According to the present invention, by forming pores in the longitudinal direction of the legs in the middle leg portion of the molded body and firing, it is generated in the binder removal temperature range during firing, which has been a problem in the past particularly for large cores. The occurrence of frequently occurring cracks could be effectively suppressed.
【図面の簡単な説明】
【図１】本発明を適用したＥ型コアの斜視図である。
【図２】脱バインダー時に発生した割れ欠陥を有する大
型ＥＲコアの斜視図である。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an E-shaped core to which the present invention is applied. FIG. 2 is a perspective view of a large ER core having a crack defect generated during binder removal.
Claims (1)
有機物系のバインダーを加え、圧縮成形して成形体を作
成し、該成形体を焼成し、ソフトフェライトＥ型コアを
製造するに際して、前記成形体の中脚部に脚長手方向一
端面から脚長手方向に直径が１mm以下の所定深さの細孔
を設けて焼成することを特徴とするソフトフェライトＥ
型コアの製造方法。(57) [Claims 1] An adjusted ferrite raw material having a predetermined composition.
An organic binder is added and compression molding is performed to produce a molded body.
And the formed body is fired to form a soft ferrite E-type core.
In the production, the leg-side direction one center leg of the molded body
Soft ferrite E characterized by providing pores having a predetermined depth of 1 mm or less from the end face in the longitudinal direction of the leg and firing.
Mold core manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20326293A JP3408587B2 (en) | 1993-08-17 | 1993-08-17 | Method of manufacturing soft ferrite E-type core |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20326293A JP3408587B2 (en) | 1993-08-17 | 1993-08-17 | Method of manufacturing soft ferrite E-type core |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0757925A JPH0757925A (en) | 1995-03-03 |
| JP3408587B2 true JP3408587B2 (en) | 2003-05-19 |
Family
ID=16471127
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20326293A Expired - Fee Related JP3408587B2 (en) | 1993-08-17 | 1993-08-17 | Method of manufacturing soft ferrite E-type core |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3408587B2 (en) |
-
1993
- 1993-08-17 JP JP20326293A patent/JP3408587B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0757925A (en) | 1995-03-03 |
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