JPS59119711A - Magnetic core - Google Patents

Abstract

PURPOSE:To obtain a core which has the constant permeability characteristics without providing a gap to the magnetic path by a method wherein, when the core is prepared by compression forming of the mixture of magnetic powder and binding material, at least two regions, which have different content of magnetic powder, is provided to the cross section perpendicular to the direction of the flux which flows through the magnetic path. CONSTITUTION:Pure iron powder, whose average particle diameter is 63-100mum, is used as magnetic powder and epoxy resin is used as binding material and an annular mold is filled with the mixture of above components which has the required ratio of mixing. The ratio of mixing is changed step by step so that the core is composed of the layers each of which has different ratio of mixing. For instance, the layers have the volume ratio of mixing such as 65:35, 70:30, 75:25 and 80:20 and each layer is filled in accordance with this order. The thickness of each layer is approximately 6-8mm.. After the filling, the whole body is compressed and formed at 600 MPa and processed by heat at 200 deg.C for about one hour to harden the resin. Thus the air gap in the magnetic path becomes unnecessary and the core is suitable for an electric device such as a reactor.

Description

【発明の詳細な説明】 〔発明の技術分野〕 本発明は磁心に関し、更に詳しくは、恒透磁率特性を有
する磁心に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to magnetic cores, and more particularly to magnetic cores having constant magnetic permeability characteristics.

〔発明の技術的背景とその問題点〕[Technical background of the invention and its problems]

従来から、交流を直流に変換する装置、直流を交流に変
換する装置、ある周波数の交流を異なる周波数の交流に
変換する装置及びいわゆるチョツノ４など直流を直流に
変換する装置のような電力変換装置、若しくは無接点遮
断器などの電気機器には、その電気回路構成要素として
、サイリスク、トランジスタで代表される半導体スイッ
チング素子及びそれに接続されるターンオンストレス緩
和用のりアクドル、転流リアクトル、エネルギー蓄積用
のりアクドルなどが使用されている。Conventionally, power conversion devices such as devices that convert alternating current to direct current, devices that convert direct current to alternating current, devices that convert alternating current of a certain frequency to alternating current of a different frequency, and devices that convert direct current to direct current such as so-called Chotsuno 4 have been used. , or non-contact circuit breakers and other electrical equipment, the electrical circuit components include cyrisk, semiconductor switching elements such as transistors, turn-on stress mitigation glue acdles, commutation reactors, and energy storage glue connected to them. Akudol etc. are used.

これらのりアクドルにとっては、そこに流れる電流が変
動してもインダクタンスの変化の少ない方が特性上望ま
しいととである。このことは、リアクトルを構成する磁
心が恒透磁率特性を具備すべきことを意味する。From the viewpoint of characteristics, it is preferable for these saddles that the inductance changes less even if the current flowing through them fluctuates. This means that the magnetic core that constitutes the reactor should have constant magnetic permeability characteristics.

ところで、従来からりアクドルの磁心としては、電磁鋼
板、・ぐ−マロイ板などを複数枚積層して構成した積層
鉄心、又は、フェライト粉末などの軟質磁性粉末をエポ
キシ樹脂のような電気絶縁性の粘結材で成形してなるフ
ェライトコアなどが主に使用されてきた。By the way, conventionally, the magnetic core of the Kaririacdle is a laminated core made by laminating multiple layers of electromagnetic steel sheets, gumalloy plates, etc., or a soft magnetic powder such as ferrite powder and an electrically insulating material such as epoxy resin. Ferrite cores made of caking material have been mainly used.

しかしながら、上記したこれらの磁心はいずれもその磁
化曲線が励磁力に対して直線的な関係を示さない。However, the magnetization curves of the above-mentioned magnetic cores do not show a linear relationship with the excitation force.

したがって、これらの磁心に恒透磁率特性を付与するた
めには、磁心の磁路の一部に空隙を形成するという手段
が講じられている。Therefore, in order to impart constant magnetic permeability characteristics to these magnetic cores, a measure has been taken to form a gap in a part of the magnetic path of the magnetic core.

このような手段は、磁心への恒透磁率特性の付与という
点では有効々ものではあるが、しかし、空隙の形成に伴
って次のような不都合な問題が派生してくる。Although such means are effective in imparting constant magnetic permeability characteristics to the magnetic core, the following disadvantages arise due to the formation of air gaps.

第１の問題は、磁心に空隙を形成するということは、磁
心の構造上、磁心を分割することにな見そのため、分割
された磁心（片）をそれぞれ磁心とは別の部材で支持し
なければならないということである。The first problem is that forming a gap in the magnetic core does not mean dividing the magnetic core due to the structure of the magnetic core. Therefore, each divided magnetic core (piece) must be supported by a separate member from the magnetic core. This means that it must be done.

第２の問題は、空隙長が変化するとその磁心が構成する
りアクドルのインダクタンスが激しく変動するというこ
とである。したがって、リアクトルのインダクタンスを
一定に保持するために、空隙長を温度など使用環境の変
化、運搬、据付は時における振動、衝撃に対して一定た
らしめるような対応策が必要になる。The second problem is that as the air gap length changes, the inductance of the magnetic core or axle changes dramatically. Therefore, in order to maintain the inductance of the reactor constant, it is necessary to take measures to keep the gap length constant against changes in the use environment such as temperature, vibrations and shocks during transportation and installation.

更に第３の問題としては、この空隙がリアクトル電流に
よる磁心の電磁力に力づく騒音発生源の１つになること
で、このことは可聴低周波帯域での使用を制限づけるも
のである。A third problem is that this air gap becomes one of the sources of noise that is exerted by the electromagnetic force of the magnetic core due to the reactor current, which limits its use in the audible low frequency band.

〔発明の目的〕[Purpose of the invention]

本発明は、磁路に空隙を設けるととなく恒透磁率特性を
示す新規な磁心を提供することに目的がある。An object of the present invention is to provide a novel magnetic core that exhibits constant magnetic permeability characteristics even when an air gap is provided in the magnetic path.

〔発明の概要〕[Summary of the invention]

本発明者らは、磁性粉と電気絶縁性の粘結材との混合物
の圧縮成形体において両者の体積混合比をわずかに変化
させた場合、該成形体の飽和磁束密度は該体積混合比の
変化と同程度に変化するが、その反面、透磁率は該体積
混合比の変化の程度よシはるかに大きく変化するという
事実に着目し、本発明の磁心を開発するに至った。す々
わち、本発明の磁心は、磁性粉と粘結材との混合物を圧
縮成形してなる磁心であって、該磁心の磁路中を流れる
磁束の向きと垂直々断面に該磁性粉の存在比の異なる領
域が少なくとも２個所存在していることを特徴とする。The present inventors found that when a compression molded body of a mixture of magnetic powder and an electrically insulating binder is slightly changed in the volumetric mixing ratio of the two, the saturation magnetic flux density of the molded body is equal to the volumetric mixing ratio. The magnetic core of the present invention was developed based on the fact that the magnetic permeability changes to a much greater extent than the change in the volumetric mixing ratio. That is, the magnetic core of the present invention is a magnetic core formed by compression molding a mixture of magnetic powder and a caking material, and the magnetic powder is formed in a cross section perpendicular to the direction of the magnetic flux flowing in the magnetic path of the magnetic core. It is characterized in that there are at least two regions with different abundance ratios.

本発明の磁心は磁性粉と粘結材との混合物の圧縮成形体
である。The magnetic core of the present invention is a compression molded product of a mixture of magnetic powder and a caking agent.

本発明に用いる磁性粉としては、軟質磁性材の粉末であ
って、例えば、純鉄の粉末：　Ｆｅ　−Ｓｉ合金、Ｆｅ
　−Ｎｉ合金、Ｆｅ　−Ａｔ合金、Ｆｅ　−Ｓｔ　−Ａ
ｔ合金など鉄基合金の粉末：　Ｍｎ　−Ｚｎフェライト
、Ｎｉ　−Ｚｎフェライトなどのフェライトの粉末をあ
げることができる。これら磁性粉の粒径は、通常、数μ
ｍ〜１００μｍ程度であればよい。The magnetic powder used in the present invention is a powder of a soft magnetic material, such as pure iron powder: Fe-Si alloy, Fe
-Ni alloy, Fe -At alloy, Fe -St -A
Powder of iron-based alloy such as t-alloy: Examples include powder of ferrite such as Mn-Zn ferrite and Ni-Zn ferrite. The particle size of these magnetic powders is usually several micrometers.
It is sufficient if it is about m to 100 μm.

また、本発明に用いる粘結材としては、磁性粉の表面を
被覆して磁性粉相互を電気絶縁状態にしかつ磁性粉を結
着するものであれば何であってもヨく、例えば、エポキ
ン樹脂、ポリアミド樹脂、？リイミド樹脂、ポリエステ
ル樹脂、ポリカーブネート樹脂をあげることができる。Furthermore, the caking agent used in the present invention may be any material that coats the surface of the magnetic powder to electrically insulate the magnetic powder from each other and bind the magnetic powder. For example, Epokin resin , polyamide resin, ? Examples include limide resin, polyester resin, and polycarnate resin.

本発明の磁心の最大の特徴は、磁路の任意な位置で該磁
路を切断して垂直な面を露出させたとき、その露出面で
は、観察される磁性粉と粘結材とが該露出面全域に亘っ
て均一に分散しているのではなく、磁性粉の分散する密
度の異なる領域、すなわち磁性粉の存在比の異なる領域
が少なくとも２個所存在するところにある。The greatest feature of the magnetic core of the present invention is that when the magnetic path is cut at an arbitrary position to expose a perpendicular surface, the observed magnetic powder and caking material are separated from each other on the exposed surface. The magnetic powder is not uniformly dispersed over the entire exposed surface, but there are at least two regions in which the magnetic powder is dispersed in different densities, that is, regions in which the abundance ratio of the magnetic powder is different.

本発明の磁心にかかる垂直面のいくつかの態様を模式図
として第１図〜第４図に示す。図中、黒点は磁性粉を表
わす。Several aspects of the vertical plane of the magnetic core of the present invention are schematically shown in FIGS. 1 to 4. In the figure, black dots represent magnetic powder.

例えば、第１図の態様は、断面が５つの層状の領域から
構成されていて、最下層１での磁性粉の存在比は最大で
あシ、順次上層２→５になるにつれて磁性粉の存在比が
低下するものである。第２図、第４図の態様においても
各層はそこに存在する磁性粉の分散密度が異なるもので
ある。また、第３図の態様は、断面の中に磁性粉の存在
比の異なる不定形の領域が埋設されたものである。For example, in the embodiment shown in FIG. 1, the cross section is composed of five layered regions, and the abundance ratio of magnetic powder is the highest in the bottom layer 1, and the abundance ratio of magnetic powder is sequentially increased from the upper layer 2 to 5. The ratio decreases. In the embodiments of FIGS. 2 and 4 as well, each layer has a different dispersion density of the magnetic powder present therein. Further, in the embodiment shown in FIG. 3, irregularly shaped regions having different abundance ratios of magnetic powder are embedded in the cross section.

いずれにしても、本発明磁心の断面は、磁性粉の存在比
の異なる領域が複数個存在していればよい。この領域は
、磁路方向に沿って一体的に連続していて、いわば゛金
太部飴“の模様の如き態様で磁心の磁路を循環して存在
している。In any case, it is sufficient that the cross section of the magnetic core of the present invention includes a plurality of regions having different abundance ratios of magnetic powder. This region is integrally continuous along the direction of the magnetic path, and exists circulating through the magnetic path of the magnetic core in a so-called ``golden candy'' pattern.

これらの断面の態様のうち、製造の容易さの点からして
第１図のようなものが好ましい。Among these cross-sectional shapes, the one shown in FIG. 1 is preferable from the viewpoint of ease of manufacture.

また、各領域における磁性粉の存在比、又は領域の形態
、数などは、目的とする磁心に求められている必要特性
との関係から定められるものであって、一義的に決める
ことはできない。Further, the abundance ratio of magnetic powder in each region, the shape of the regions, the number of regions, etc. are determined based on the relationship with the necessary characteristics required of the intended magnetic core, and cannot be determined uniquely.

本発明の磁心は例えば次のような方法で製造することが
できる。その方法を断面が第１図の態様である磁心を例
にして説明する。The magnetic core of the present invention can be manufactured, for example, by the following method. The method will be explained using an example of a magnetic core whose cross section is as shown in FIG.

第１の方法は、まず所定粒径の磁性粉と粘結材を用意し
両者を種々の体積混合比で混合して磁性粉の存在比が異
なる混合物にする。各混合物を環状の型の中に、順次所
定厚みの層状に充填した後、全体を圧縮成形して一体的
な成形体とする。なお、この処理の前に、各混合物をそ
れぞれ所定厚みの板状体に予備成形しておき、これら予
備成形体を順次積層してから全体を圧縮成形してもよい
。In the first method, first, magnetic powder of a predetermined particle size and a caking agent are prepared, and the two are mixed at various volume mixing ratios to form a mixture in which the abundance ratio of the magnetic powder is different. Each mixture is sequentially filled into an annular mold in layers of a predetermined thickness, and then the entire mixture is compression molded to form an integral molded body. Note that, before this treatment, each mixture may be preformed into a plate-like body of a predetermined thickness, and these preformed bodies may be sequentially laminated and then compression molded as a whole.

得られた成形体はそのまま本発明の磁心として供するこ
ともできるが、必要に応じては、該成形体を例えば２０
０℃で１時間和熱処理して粘結材を硬化せしめることも
できる。The obtained molded body can be used as it is as the magnetic core of the present invention, but if necessary, the molded body may be
The binder can also be cured by heat treatment at 0° C. for 1 hour.

かくして、得られた磁心の磁束の向きに垂直な断面では
、磁性粉の存在比が異なる領域が層状に積層されること
になる。In this way, in the cross section perpendicular to the direction of the magnetic flux of the obtained magnetic core, regions with different abundance ratios of magnetic powder are laminated in layers.

第２の方法は、硬度が異なる２種類以上の磁性粉を用意
し、これら磁性粉をそれぞれ粘結材と同一体積混合比で
混合し、各混合物を第１の方法と同様にして圧縮成形す
る方法である。この場合、各混合物における磁性粉と粘
結材との体積混合比は同じであるにもかかわらず、圧縮
成形して全体を一体化したとき硬度の低い磁性粉の方が
硬度の高い磁性粉の場合よシも粘結材への充填率が大き
くなり、その結果、成形体の中には磁性粉の存在比の勾
配が生ずる。In the second method, two or more types of magnetic powder with different hardnesses are prepared, each of these magnetic powders is mixed with a caking agent at the same volume mixing ratio, and each mixture is compression molded in the same manner as in the first method. It's a method. In this case, even though the volumetric mixing ratio of magnetic powder and caking agent in each mixture is the same, when the whole mixture is compressed and molded, the magnetic powder with lower hardness is larger than the magnetic powder with higher hardness. In all cases, the filling rate of the caking agent increases, and as a result, a gradient in the abundance ratio of magnetic powder occurs in the molded body.

かくして、この場合にあっても断面では磁性粉の存在比
の異なる領域を形成することが可能となる。In this way, even in this case, it is possible to form regions with different abundance ratios of magnetic powder in the cross section.

〔発明の実施例〕[Embodiments of the invention]

実施例１ 磁性粉として平均粒径６３〜１００μｍの純鉄の粉末、
粘結材としてエポキシ樹脂をそれぞれ用意した。Example 1 Pure iron powder with an average particle size of 63 to 100 μm as magnetic powder,
Epoxy resin was prepared as a binding material.

鉄粉とエポキシ樹脂の体積混合比がそれぞれ、６５：３
５，７０：３０，７５：２５，８０：２０．８４：１６
，８８：１２，９２：８，９５：５，９８：２である９
種類の混合物を調製した。Volume mixing ratio of iron powder and epoxy resin is 65:3, respectively.
5, 70:30, 75:25, 80:20.84:16
, 88:12, 92:8, 95:5, 98:2 9
A mixture of types was prepared.

これらの混合物を、磁心成形用の円環状型の中に、上記
した順序で充填した。各層の厚みは６〜８ｍであった。These mixtures were filled in an annular mold for forming a magnetic core in the order described above. The thickness of each layer was 6-8 m.

ついで、全体を６００ＭＰａで圧縮成形した。得られた
成形体を２００℃で１時間熱処理してエポキシ樹脂を硬
化した。外径１５０＋ｍ内径９０調高さ３０ｍの円環磁
心が得られた。The whole was then compression molded at 600 MPa. The obtained molded body was heat-treated at 200° C. for 1 hour to harden the epoxy resin. A circular magnetic core with an outer diameter of 150+ m and an inner diameter of 90 m and a height of 30 m was obtained.

この磁心につき、常法によって励磁力と透磁率との関係
を調べた。その結果を曲線Ａとして第５図に示した。な
お、比較のため、従来の電磁鋼板からなる磁心の結果を
曲線Ａ′として示した。Regarding this magnetic core, the relationship between excitation force and magnetic permeability was investigated using conventional methods. The results are shown as curve A in FIG. For comparison, the results for a magnetic core made of a conventional electromagnetic steel sheet are shown as curve A'.

実施例２ 磁性粉として、純鉄粉末、Ｆｅ−１，Ｏ％Ｓｉ合金粉末
、Ｆｅ　−３，０％　８１合金粉末及びＦｅ−５，０％
Ｓｔ合金粉末の硬度の異なる４種類の粉末を用いた。Example 2 As magnetic powder, pure iron powder, Fe-1,0%Si alloy powder, Fe-3,0% 81 alloy powder, and Fe-5,0%
Four types of St alloy powders having different hardnesses were used.

これらの粉末で硬度は上記した順に大きくなる。The hardness of these powders increases in the order listed above.

また、これら粉末の平均粒径は１００μｍであった。Moreover, the average particle size of these powders was 100 μm.

これら４種類の粉末それぞれを混合容積に対し１２チ相
尚の体積比のエポキシ樹脂と混合して混合物を調製した
。A mixture was prepared by mixing each of these four types of powder with an epoxy resin in a volume ratio of 12 to the mixing volume.

これらの混合物を実施例１と同様に円環状型内に上記の
順序で充填し全体を４００ＭＰａで圧縮成形して成形体
とした。この成形体を２００℃で１時間熱処理してエポ
キシ樹脂を硬化した。外径１２０瓢内径８０ｍ高さ２０
瓢の円環磁心が得られた。These mixtures were filled into an annular mold in the same manner as in Example 1 in the above order, and the whole was compression molded at 400 MPa to obtain a molded body. This molded body was heat treated at 200° C. for 1 hour to harden the epoxy resin. Outer diameter 120mm Inner diameter 80m Height 20
A gourd toroidal core was obtained.

との磁心の励磁力と透磁率との関係を第５図の曲線Ｂと
して示した。The relationship between the excitation force of the magnetic core and the magnetic permeability is shown as curve B in FIG.

〔発明の効果〕〔Effect of the invention〕

以上の説明で明らかなように、本発明の磁心は、■恒透
磁率特性に優れリアクトル用の磁心として有用である、
■磁路には空隙を形成する必要がないので、空隙の存在
が引き起こしていた多くの問題点を解消する、などの効
果を奏しその工業的価値は極めて大である。As is clear from the above description, the magnetic core of the present invention has (1) excellent constant magnetic permeability characteristics and is useful as a magnetic core for a reactor;
■Since there is no need to form air gaps in the magnetic path, many problems caused by the presence of air gaps can be solved, and its industrial value is extremely large.

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

第１図〜第４図は本発明の磁心の断面の状態を例示する
図であシ、第５図は本発明の磁心及び従来の磁心の励磁
力と透磁率との関係曲線である。 第５図中、曲線Ａ、Ｂは本発明の磁心、曲線Ａ′は従来
の磁心を表わす。1 to 4 are diagrams illustrating the state of the cross section of the magnetic core of the present invention, and FIG. 5 is a relationship curve between excitation force and magnetic permeability of the magnetic core of the present invention and the conventional magnetic core. In FIG. 5, curves A and B represent the magnetic core of the present invention, and curve A' represents the conventional magnetic core.

Claims (1)

【特許請求の範囲】 磁性粉と粘結材との混合物を圧縮成形してなる磁心であ
って、 該磁心の磁路中を流れる磁束の向きと垂直な断面に 該磁性粉の存在比の異なる領域が 少なくとも２個所存在していることを特徴とする磁心。[Claims] A magnetic core formed by compression molding a mixture of magnetic powder and a caking material, wherein the abundance ratio of the magnetic powder is different in a cross section perpendicular to the direction of magnetic flux flowing in the magnetic path of the magnetic core. A magnetic core characterized by having at least two regions.