JP3990739B2 - Method for manufacturing electromagnetic induction element - Google Patents

Description

【０００７】
図６を参照して、数１式によるギャップ距離Ｘと比透磁率μ_s の変化率Ｙとの関係により、ギャップ距離Ｘが１５μｍの場合、比透磁率μ_s は約５０％程度まで低下する。比透磁率μ_s は、インダクタンス値に直接関係する因子であり、この比透磁率μ_s の低下は、電磁誘導素子のインダクタンス特性の低下をもたらすことになる。
【０００８】
そこで、本発明の技術的課題は、透磁率の低下を防止でき、優れたインダクタンス特性を有する電磁誘導素子を得ることにある。
【０００９】
【課題を解決するための手段】
本発明によれば、複数の軟磁性体コアを、閉磁路を構成するように当接した接合部を有する閉磁路磁心と、該磁心に装着されたコイルボビンと、該コイルボビンに巻回されたコイルとを有する電磁誘導素子を製造する方法において、複数の前記軟磁性体コアの当接面の中央部に凹部を形成する工程と、前記凹部の周囲を平滑平面とする工程と、前記凹部に、充填材として比透磁率が１より大きな軟磁性金属材料を含む材料をメッキ法によって施すことにより前記凹部をメッキ層で充満する工程と、前記メッキ層の表面を研磨する工程と、前記コイルを巻回したコイルボビンを前記軟磁性体コアに組み合わせ、前記当接面を接合する工程と、を有することを特徴とする電磁誘導素子の製造方法が得られる。
【００１０】
また、本発明によれば、複数の軟磁性体コアを、閉磁路を構成するように当接した接合部を有する閉磁路磁心と、該磁心に装着されたコイルボビンと、該コイルボビンに巻回されたコイルとを有する電磁誘導素子を製造する方法において、複数の前記軟磁性体コアの当接面の中央部に凹部を形成する工程と、前記凹部の周囲を平滑平面とする工程と、前記凹部に、前記充填材として比透磁率が１より大きなセラミック材料および軟磁性金属材料の一方を含む材料をスパッタリング法によって施すことにより前記凹部をスパッタリング層で充満する工程と、前記スパッタリング層の表面を研磨する工程と、前記コイルを巻回したコイルボビンを前記軟磁性体コアに組み合わせ、前記当接面を接合する工程と、を有することを特徴とする電磁誘導素子の製造方法が得られる。
【００１１】
【作用】
比透磁率が１より大きな軟磁性材料を主体とする充填材は、軟磁性体コアの当接面の凹部に充満される。充填材は当接面の空気と置換され軟磁性体コア同士が接合される。この結果、エアギャップのない完全な閉磁路磁心が形成される。
【００１２】
【実施例】
本発明の一実施例による電磁誘導素子を図面を用いて説明する。
【００１３】
図１及び図２に示すように、本発明の一実施例による電磁誘導素子は、１対の軟磁性Ｕ形コア１１，１２と、両端に鍔を持ち中空の筒状のボビン１３と、ボビン１３に巻回されるコイル１４と、比透磁率μ_siの充填材２５とを備えている。この電磁誘導素子は、当接面が互いに接合されるコア接合部を有する閉磁路磁心を備えている。
【００１４】
図３（ａ）、（ｂ）、（ｃ）に示すように、１対の軟磁性Ｕ形コア１１，１２の当接面の中央部１１−１，１２−１には、充填材２５が充満される凹部１１ａ，１２ａが形成されている。ボビン１３の中空の穴の中央には、閉磁路磁心の接合部が配される。コア接合部には、凹部１１ａ，１２ａによって一定体積の空気を保持する間隙、即ち、エアギャップが形成されるが、この間隙中の空気は前述の充填材２５で置換されている。
【００１５】
本実施例の電磁誘導素子を製造するには、まず、閉磁路磁心を構成する複数の軟磁性Ｕ形コア１１，１２を用意する。軟磁性Ｕ形コア１１，１２の当接面の中央部１１−１，１２−１に凹部１１ａ，１２ａを形成する。
【００１６】
一方、別に、コイル１４を巻回したコイルボビン１３を用意する。
【００１７】
また、当接面周囲の外周部１１−２，１２−１には、当接面の相互接触が十分行われるようにコア材と同じものをすり合わせ処理を施して平滑平面にする。
【００１８】
軟磁性Ｕ形コア１１，１２の当接面の凹部１１ａ，１２ａに比透磁率が１より大きな軟磁性材料を主体とする充填材２５を充満する。
【００１９】
その後、コイル１４を巻回したコイルボビン１３がコア接合部で取り囲むように、コイルボビン１３の穴の中央で当接面を接合してコア接合部を形成する。この結果、閉磁路磁心が形成され、電磁誘導素子を得ることがきる。
【００２０】
次に、図４（ａ）、（ｂ）を参照して、エアギャップの空気と置換させるための充填材２５について述べる。
【００２１】
充填材２５は、空気の置換材料として、比透磁率が１より大で、かつ周波数特性の良好な、（Ｉ）金属又は合金材料、（II）セラミックス材料、(III) （Ｉ）の金属又は合金材料、（II）のセラミックス材料の一方に接着効果の有る材料を混合させたもののいずれかを用いる。
【００２２】
これらの材料の形状、状態は、以下のように列挙される。
【００２３】
材料（Ｉ）：（１）微細粉末状、（２）メッキ状、（３）スパッタリング法による薄膜状
材料（II）：（４）微細粉末状、（５）スパッタリング法による薄膜状
材料（III)：（６）微細粉末、有機バインダー及び溶剤が混合されたペースト状
以上、（１）〜（６）のいずれかの材料を充填材２５として用いる。
【００２４】
これら、（Ｉ）〜（III)材料における（１）〜（６）の状態の比透磁率は、各々のバルク状態に比べ小さいが、図５に示すように、充填材２５の比透磁率μ_siの値が、閉磁路磁心の比透磁率を大きく左右するからである。
【００２５】
さらに、いずれの挿入材料も空気と置換する前後でエアギャップの体積を増加させないことが必要である。何故なら、エアギャップの体積の増加は、図７に示すように閉磁路磁心の比透磁率μ_scが著しい低下をもたらすからである。
【００２６】
その上、充填材は、比透磁率が１より大きな軟磁性材料と接着効果を示す接着性材料との混合物であっても良い。
【００２７】
接着力を得るために接着性材料を使用しないで、図６のコアホルダ１５をバネ材部品として使用することによりコア同士を挾持し機械的に接合したり、テープ材でコア同士を巻回して接合したり、弾性を有する開閉式の樹脂ケースを開けてその内にコア同士を入れてから閉じてコア同士を接合しても良い。
【００２８】
尚、当接面を接合して閉磁路磁心を形成する際に、当接面に直交する方向に磁場を印加して当接面における充填材中の軟磁性材を配向させながら硬化させる方法を用いても良い。
【００２９】
以上説明したように、エアギャップの空気を比透磁率が１より大きい材料に置換させる操作により、本発明による実施例の電磁誘導素子は比透磁率μ_scが一定量上昇する。仮に、接合部に凹部１１ａ，１２ａを有しない、単純な平面状であれば、充填材２５の挿入量は一定をなさず、不純物の混入は、接合面間の距離を増大させ、閉磁路磁心の比透磁率μ_scのばらつきは大きくなってしまう。
【００３０】
図５を参照して、充填材２５の比透磁率μ_siと閉磁路磁心のコア比透磁率μ_scの回復率との関係が示されている。
【００３１】
このように、本発明は、閉磁路磁心における一定量の比透磁率を増加させ、かつ、そのばらつきを抑えるという製造上重要な２つの特徴を有する。
【００３２】
これにより、従来例とインダクタンスの値が同じ電磁誘導素子では、図１のコイル１４の巻数を相対的に少なくすることができる。巻数が少なくなれば、コイル１４に生じる分布容量や電気抵抗を少なくでき、優れたインダクタンス特性の電磁誘導素子が得られるという効果がある。
【００３３】
また、材料（III)を用いれば、挿入材料自体の接着力で、複数個のコア同士を密着固定することができる。これによって、従来必須であったコアホルダ１５を省略することができ、コスト低減が図れる。
【００３４】
次に、本発明の実施例による電磁誘導素子の充填材置換方法を具体例で説明するが、以下のものに限定されないことはいうまでもない。
【００３５】
（具体例１）
充填材２５としてフェライト粉末に接着効果を示す材料を混合させたものを用いた場合を説明する。
【００３６】
予めボビン１３にコイル１４を機械巻したものを準備する。一方、ボビン１３の穴に嵌挿するための１対の軟磁性Ｕ形コア１１，１２を加工する。即ち、これら軟磁性Ｕ形コア１１，１２の当接面に凹部１１ａ，１２ａを形成してから、外周部１１−２，１２−２をコア材と同じものですり合わせて平滑平面にする。
【００３７】
その後、定量吐出器を用いて、比透磁率が１より大きな材料を主体とする充填材２５を粘性度を適切に定めて滴下させる。その後、これら軟磁性Ｕ形コア１１，１２の当接面同士を接合し一定量の押圧を加え、連結する。
【００３８】
この電磁誘導素子に適切な交流又は直流電流を流すことにより、コイル１４の周りに磁束が発生し閉磁路磁心の中央を通過する。この結果、充填材２５中の軟磁性体粉末材料が閉磁路磁心の中央の閉磁路に沿って配向され硬化し、電磁誘導素子を得ることができる。軟磁性体粉末材料を配向・硬化することにより、乱雑で非接触な配列を透磁率が極めて高い直列接触配列とすることができる。
【００３９】
また、０．１〜４０μｍの粒度分布を持たせれば、粒径大の隙間に粒径小のものを充填し、高い充填密度を得ることができる結果、高い比透磁率μ_scを保つことができる。
【００４０】
（具体例２）
図４（ａ）に示すように、軟磁性Ｕ形コア１１，１２がフェライト製であって一方の軟磁性Ｕ形コア１２の当接面の凹部１２ａの空気をメッキ層で置換するメッキ法を使用する場合を説明する。一方の軟磁性Ｕ形コア１２の当接面に凹部１２ａを形成した後、外周部１２−２をコア材と同じものですり合わせて平滑平面にする。
【００４１】
次に、比透磁率が１より大きな軟磁性金属材料を用いて厚みが５０μｍのメッキ層２５を凹部１２ａに充満させる。その後、図４（ｂ）に示すように、メッキ層２５を研磨して研磨面２５ｂを形成してから、この研磨面２５ｂに他方の軟磁性Ｕ形コア１１の接合面を接合する。
【００４２】
研磨面２５ｂとなる金属は、コア材のフェライトに比べ硬度が低く一般に加工性が良いものを用い、メッキ層２５のみを研磨するので、コア当接面の凹凸や割れの空気を充填材で充分置換できる。
【００４３】
ところで、軟磁性Ｕ形コア１１，１２の両方をメッキ処理を施す場合には、エアギャップ中の空気の占める体積を大幅に少なくすることができる。この結果、閉磁路磁心の比透磁率μ_scの回復率を高めることができる。
【００４４】
（具体例３）
コア当接面の凹部の空気を充填材で置換する方法として具体例２のメッキ法の代わりにスパッタリング法を用いる場合、緻密なスパッタリング薄膜を形成でき、スパッタリング薄膜を研磨して研磨面を形成できる。
【００４５】
この結果、コア当接面の凹部の空気を充填材で完全に置換され、図５で示すように、具体例２の場合に比べて閉磁路磁心の比透磁率μ_scの回復率をより高めることができる。
【００４６】
【発明の効果】
以上示したように本発明によれば、比透磁率が１より高い充填材を接合部の凹部に充満させたので、従来例より、閉磁路磁心の比透磁率は増加し、インダクタンスを増加できる。しかも、インダクタンスの値が従来例と同じものを得る場合には、コイルの巻数を減少できるという効果を奏する。
【図面の簡単な説明】
【図１】本発明の一実施例による電磁誘導素子の製造方法を説明するための分解図である。
【図２】図１の本発明の一実施例による電磁誘導素子を組み立てた図である。
【図３】図２の電磁誘導素子の接合部を説明するための図である。
【図４】メッキ法やスパッタリング法による軟磁性Ｕ形コアの当接面処理を説明するための図である。
【図５】本発明の一実施例による電磁誘導素子に関し、重点剤２５の比透磁率μ_ｓｉを変えたときの、比透磁率μ_ｓｉとコア比透磁率μ_ｓｃの回復率との関係が示されている。この実施例による電磁誘導素子は、磁路長Ｌ：５０ｍｍ、コア比透磁率μ_ｓｃ：４００、コアギャップ距離Ｘ：１５μｍであり、回復率１００％は、コアギャップなしに対応する。
【図６】電磁誘導素子の従来例を示す図である。
【図７】磁路長Ｌ：５０ｍｍ、コア比透磁率μ_sc：４０００、空気の比透磁率μ_sa：１の電磁誘導素子の従来例に関し、ギャップ距離Ｘと比透磁率μ_s の相対変化率との関係が示されている。ここで、相対変化率１００％は、コアギャップなしに対応する。
【符号の説明】
１１、１２ 軟磁性Ｕ形コア
１１ａ、１２ａ 凹部
１１−１、１２−１ 中央部
１１−２、１２−２ 外周部
１３ ボビン
１４ コイル
１５ コアホルダ
２５ 充填材[0001]
[Industrial application fields]
The present invention relates to manufacturing of electromagnetic induction elements such as choke coils and transformers and a manufacturing method thereof, and more particularly to an electromagnetic induction element having a closed magnetic path magnetic core having a joint portion in contact with a plurality of cores.
[0002]
[Prior art]
Conventionally, this type of electromagnetic induction element includes a closed magnetic circuit core type having a joint portion in which a plurality of soft magnetic cores are in contact with each other so as to form a closed magnetic circuit. As shown in FIG. A pair of soft magnetic U-shaped cores 11 and 12 and a cylindrical coil bobbin 13 which is mounted so as to surround a joint portion of a closed magnetic path magnetic core, and a coil wound around the coil bobbin 13 ( (Guide wire) 14 and a core holder 15 for holding an assembly of these components, and is applied to, for example, a high-frequency choke coil.
[0003]
[Problems to be solved by the invention]
However, the contact surfaces of the soft magnetic cores 11 and 12 are likely to have microscopic irregularities and cracks generated in the process, and the air layer, that is, the air gap is formed in the closed magnetic circuit based on these irregularities and cracks. Will exist. This air gap has an air relative permeability of almost 1, and is relatively small compared to the relative permeability of the soft magnetic core.
[0004]
Therefore, even if the gap distance is small, the magnetic resistance of the air gap is not negligible compared to the soft magnetic core. As a result, the closed core magnetic core of the entire core constituting the closed magnetic path has a magnetic permeability. Decrease significantly.
[0005]
For example, if air with a gap distance of X (μm) enters a magnetic path length of the entire closed magnetic path core having no air gap of 50 (mm) and a relative permeability of 4000, the overall relative permeability of The rate of change Y (%) can be obtained from the following equation (1).
[0006]
[Expression 1]

[0007]
Referring to FIG. 6, due to the relationship between the gap distance X and the change rate Y of the relative permeability μ _s according to Equation 1, when the gap distance X is 15 μm, the relative permeability μ _s decreases to about 50%. . The relative permeability μ _s is a factor directly related to the inductance value, and the decrease in the relative permeability μ _s results in a decrease in the inductance characteristics of the electromagnetic induction element.
[0008]
Therefore, a technical problem of the present invention is to obtain an electromagnetic induction element that can prevent a decrease in magnetic permeability and has excellent inductance characteristics.
[0009]
[Means for Solving the Problems]
According to the present invention, a closed magnetic path magnetic core having a joining portion in which a plurality of soft magnetic cores are in contact so as to form a closed magnetic path, a coil bobbin attached to the magnetic core, and a coil wound around the coil bobbin A step of forming a recess at the center of the contact surfaces of the plurality of soft magnetic cores, a step of making the periphery of the recess a smooth flat surface, and Filling the concave portion with a plating layer by applying a material containing a soft magnetic metal material having a relative permeability greater than 1 as a filler by plating, polishing the surface of the plating layer, winding the coil And a step of combining the rotated coil bobbin with the soft magnetic core and joining the contact surfaces.
[0010]
Further, according to the present invention, a plurality of soft magnetic cores are wound around the coil bobbin, a closed magnetic circuit core having a joint that abuts to form a closed magnetic circuit, a coil bobbin attached to the magnetic core, and the coil bobbin. In the method of manufacturing an electromagnetic induction element having a coil, a step of forming a recess at the center of the contact surface of the plurality of soft magnetic cores, a step of making the periphery of the recess a smooth flat surface, and the recess And applying a material containing one of a ceramic material having a relative permeability greater than 1 and a soft magnetic metal material as the filler by a sputtering method, and polishing the surface of the sputtering layer. And combining the coil bobbin around which the coil is wound with the soft magnetic core and joining the contact surface. Method of manufacturing a child can be obtained.
[0011]
[Action]
A filler mainly composed of a soft magnetic material having a relative permeability greater than 1 is filled in the concave portion of the contact surface of the soft magnetic core. The filler is replaced with air on the contact surface, and the soft magnetic cores are joined together. As a result, a complete closed magnetic circuit core without an air gap is formed.
[0012]
【Example】
An electromagnetic induction device according to an embodiment of the present invention will be described with reference to the drawings.
[0013]
As shown in FIGS. 1 and 2, an electromagnetic induction device according to an embodiment of the present invention includes a pair of soft magnetic U-shaped cores 11 and 12, a hollow cylindrical bobbin 13 having ridges at both ends, and a bobbin. 13 is provided with a coil 14 wound around 13 and a filler 25 having a relative magnetic permeability μ _si . This electromagnetic induction element includes a closed magnetic path magnetic core having a core joint portion whose contact surfaces are joined to each other.
[0014]
As shown in FIGS. 3A, 3 </ b> B, and 3 </ b> C, the filler 25 is provided in the center portions 11-1 and 12-1 of the contact surfaces of the pair of soft magnetic U-shaped cores 11 and 12. The filled recesses 11a and 12a are formed. In the center of the hollow hole of the bobbin 13, a joint portion of the closed magnetic path magnetic core is disposed. A gap for holding a constant volume of air, that is, an air gap, is formed in the core joint by the recesses 11a and 12a. The air in the gap is replaced with the filler 25 described above.
[0015]
In order to manufacture the electromagnetic induction element of this embodiment, first, a plurality of soft magnetic U-shaped cores 11 and 12 constituting a closed magnetic path magnetic core are prepared. Concave portions 11a and 12a are formed in the central portions 11-1 and 12-1 of the contact surfaces of the soft magnetic U-shaped cores 11 and 12, respectively.
[0016]
On the other hand, a coil bobbin 13 around which the coil 14 is wound is prepared.
[0017]
In addition, the outer peripheral portions 11-2 and 12-1 around the contact surface are subjected to a rubbing process so as to make a smooth flat surface so that the contact surfaces are sufficiently brought into mutual contact.
[0018]
The recesses 11 a and 12 a on the contact surfaces of the soft magnetic U-shaped cores 11 and 12 are filled with a filler 25 mainly composed of a soft magnetic material having a relative permeability larger than 1.
[0019]
Thereafter, the contact surface is joined at the center of the hole of the coil bobbin 13 so that the coil bobbin 13 around which the coil 14 is wound is surrounded by the core joint, thereby forming the core joint. As a result, a closed magnetic path magnetic core is formed, and an electromagnetic induction element can be obtained.
[0020]
Next, with reference to FIGS. 4A and 4B, the filler 25 for replacing air in the air gap will be described.
[0021]
The filler 25 is, as a replacement material for air, (I) a metal or alloy material, (II) a ceramic material, (III) a metal of (I), which has a relative permeability greater than 1 and good frequency characteristics. Either alloy material or (II) ceramic material mixed with a material having an adhesive effect is used.
[0022]
The shape and state of these materials are listed as follows.
[0023]
Material (I): (1) Fine powder, (2) Plating, (3) Thin film material by sputtering (II): (4) Fine powder, (5) Thin film material by sputtering (III) : (6) Paste or higher in which fine powder, organic binder and solvent are mixed. Any material of (1) to (6) is used as filler 25.
[0024]
Although the relative magnetic permeability in the states (1) to (6) in these materials (I) to (III) is smaller than the respective bulk states, the relative magnetic permeability μ of the filler 25 as shown in FIG. _{This is because} the value of _si greatly affects the relative permeability of the closed magnetic circuit core.
[0025]
Furthermore, it is necessary that any insert material does not increase the volume of the air gap before and after replacing it with air. This is because an increase in the volume of the air gap causes a significant decrease in the relative permeability μ _sc of the closed magnetic circuit core as shown in FIG.
[0026]
In addition, the filler may be a mixture of a soft magnetic material having a relative permeability greater than 1 and an adhesive material exhibiting an adhesive effect.
[0027]
By using the core holder 15 of FIG. 6 as a spring material part without using an adhesive material to obtain an adhesive force, the cores are held and mechanically joined, or the cores are wound with a tape material and joined together. Alternatively, the openable resin case having elasticity may be opened, the cores may be put in the resin case, and the cores may be closed to be joined.
[0028]
When joining the contact surfaces to form a closed magnetic path core, a method of applying a magnetic field in a direction perpendicular to the contact surfaces and curing the soft magnetic material in the filler on the contact surfaces is cured. It may be used.
[0029]
As described above, the operation of replacing the air gap air with a material having a relative permeability greater than 1 increases the relative permeability μ _sc of the electromagnetic induction element according to the embodiment of the present invention by a certain amount. If it is a simple planar shape that does not have the recesses 11a and 12a at the joint, the amount of filler 25 inserted will not be constant, and the incorporation of impurities will increase the distance between the joint surfaces and cause a closed magnetic circuit core. The variation of the relative permeability μ _sc becomes large.
[0030]
Referring to FIG. 5, the relationship between the relative permeability μ _si of the filler 25 and the recovery rate of the core relative permeability μ _sc of the closed magnetic path core is shown.
[0031]
As described above, the present invention has two important features in manufacturing that increase a specific amount of relative permeability in a closed magnetic path magnetic core and suppress variation thereof.
[0032]
Thereby, in the electromagnetic induction element having the same inductance value as that of the conventional example, the number of turns of the coil 14 in FIG. 1 can be relatively reduced. If the number of turns is reduced, the distributed capacity and electrical resistance generated in the coil 14 can be reduced, and an electromagnetic induction element having excellent inductance characteristics can be obtained.
[0033]
In addition, when the material (III) is used, the plurality of cores can be firmly fixed to each other by the adhesive force of the insertion material itself. As a result, the core holder 15 which has been essential in the past can be omitted, and the cost can be reduced.
[0034]
Next, a method for replacing the filler of the electromagnetic induction element according to the embodiment of the present invention will be described with a specific example, but it is needless to say that the method is not limited to the following.
[0035]
(Specific example 1)
A case where a material obtained by mixing a ferrite powder with a material exhibiting an adhesive effect is used as the filler 25 will be described.
[0036]
A bobbin 13 having a coil 14 wound mechanically in advance is prepared. On the other hand, a pair of soft magnetic U-shaped cores 11 and 12 for fitting into the holes of the bobbin 13 are processed. That is, after the concave portions 11a and 12a are formed on the contact surfaces of the soft magnetic U-shaped cores 11 and 12 , the outer peripheral portions 11-2 and 12-2 are rubbed together with the same core material to form a smooth plane.
[0037]
Thereafter, the filler 25 mainly composed of a material having a relative permeability greater than 1 is dripped with a viscosity determined appropriately using a fixed amount dispenser. Thereafter, the contact surfaces of the soft magnetic U-shaped cores 11 and 12 are joined to each other, and a certain amount of pressure is applied to connect them.
[0038]
By supplying an appropriate alternating current or direct current to the electromagnetic induction element, a magnetic flux is generated around the coil 14 and passes through the center of the closed magnetic circuit core. As a result, the soft magnetic powder material in the filler 25 is oriented and cured along the closed magnetic path at the center of the closed magnetic path core, and an electromagnetic induction element can be obtained. By aligning and curing the soft magnetic powder material, a random and non-contact arrangement can be made into a series contact arrangement with extremely high magnetic permeability.
[0039]
Further, if a particle size distribution of 0.1 to 40 μm is provided, a gap having a large particle size can be filled with a small particle size, and a high packing density can be obtained. As a result, a high relative permeability μ _sc can be maintained. it can.
[0040]
(Specific example 2)
As shown in FIG. 4A, a plating method is used in which the soft magnetic U-shaped cores 11 and 12 are made of ferrite, and the air in the recess 12a on the contact surface of one soft magnetic U-shaped core 12 is replaced with a plating layer. The case of using will be described. After the concave portion 12a is formed on the contact surface of one soft magnetic U-shaped core 12, the outer peripheral portion 12-2 is rubbed with the same material as the core material to form a smooth plane.
[0041]
Next, the plating layer 25 having a thickness of 50 μm is filled in the concave portion 12 a using a soft magnetic metal material having a relative permeability larger than 1. Thereafter, as shown in FIG. 4B, after the plated layer 25 is polished to form the polished surface 25b, the bonded surface of the other soft magnetic U-shaped core 11 is bonded to the polished surface 25b.
[0042]
The metal used as the polishing surface 25b is a metal having a hardness lower than that of the ferrite of the core material and generally good workability, and only the plated layer 25 is polished. Can be replaced.
[0043]
By the way, when both the soft magnetic U-shaped cores 11 and 12 are plated, the volume of air in the air gap can be greatly reduced. As a result, the recovery rate of the relative permeability μ _sc of the closed magnetic path core can be increased.
[0044]
(Specific example 3)
When the sputtering method is used instead of the plating method of Example 2 as a method of replacing the air in the concave portion of the core contact surface with the filler, a dense sputtering thin film can be formed, and the sputtering thin film can be polished to form a polished surface. .
[0045]
As a result, the air in the concave portion of the core contact surface is completely replaced with the filler, and as shown in FIG. 5, the recovery rate of the relative permeability μ _sc of the closed magnetic path magnetic core is further increased as compared with the case of the specific example 2. be able to.
[0046]
【The invention's effect】
As described above, according to the present invention, since the filler having a relative permeability higher than 1 is filled in the concave portion of the joint, the relative permeability of the closed magnetic path core can be increased and the inductance can be increased as compared with the conventional example. . Moreover, when the inductance value is the same as that of the conventional example, the number of turns of the coil can be reduced.
[Brief description of the drawings]
FIG. 1 is an exploded view for explaining a method of manufacturing an electromagnetic induction device according to an embodiment of the present invention.
2 is an assembled view of an electromagnetic induction device according to an embodiment of the present invention of FIG. 1;
FIG. 3 is a view for explaining a joint portion of the electromagnetic induction element of FIG. 2;
FIG. 4 is a view for explaining a contact surface treatment of a soft magnetic U-shaped core by a plating method or a sputtering method.
It relates electromagnetic induction device according to an embodiment of the present invention; FIG, when changing the relative permeability mu _si priority agent 25, the relationship between the relative magnetic permeability mu _si and the core relative permeability mu _sc recovery rate It is shown. The electromagnetic induction element according to this example has a magnetic path length L: 50 mm, a core relative permeability μ _sc : 400, a core gap distance X: 15 μm, and a recovery rate of 100% corresponds to no core gap.
FIG. 6 is a diagram showing a conventional example of an electromagnetic induction element.
FIG. 7 shows a relative change in the gap distance X and the relative permeability μ _s for a conventional example of an electromagnetic induction element having a magnetic path length L: 50 mm, a core relative permeability μ _sc : 4000, and an air relative permeability μ _sa : 1. The relationship with rate is shown. Here, a relative change rate of 100% corresponds to no core gap.
[Explanation of symbols]
11, 12 Soft magnetic U-shaped cores 11a, 12a Recesses 11-1, 12-1 Central portion 11-2, 12-2 Outer peripheral portion 13 Bobbin 14 Coil 15 Core holder 25 Filler

Claims (2)

An electromagnetic induction element having a closed magnetic path magnetic core having a joint portion in which a plurality of soft magnetic cores are contacted so as to form a closed magnetic path, a coil bobbin mounted on the magnetic core, and a coil wound around the coil bobbin In the method of manufacturing
Forming a recess in the center of the contact surface of the plurality of soft magnetic cores;
A step of making the periphery of the recess a smooth plane;
Filling the concave portion with a plating layer by applying a material containing a soft magnetic metal material having a relative permeability larger than 1 as a filler to the concave portion by a plating method;
Polishing the surface of the plating layer;
Combining the coil bobbin around which the coil is wound with the soft magnetic core, and joining the contact surface;
The manufacturing method of the electromagnetic induction element characterized by having. An electromagnetic induction element having a closed magnetic path magnetic core having a joint portion in which a plurality of soft magnetic cores are contacted so as to form a closed magnetic path, a coil bobbin mounted on the magnetic core, and a coil wound around the coil bobbin In the method of manufacturing
Forming a recess in the center of the contact surface of the plurality of soft magnetic cores;
A step of making the periphery of the recess a smooth plane;
Filling the recess with a sputtering layer by applying a material containing one of a ceramic material having a relative permeability greater than 1 and a soft magnetic metal material as the filler to the recess by a sputtering method;
Polishing the surface of the sputtering layer;
Combining the coil bobbin around which the coil is wound with the soft magnetic core, and joining the contact surface;
The manufacturing method of the electromagnetic induction element characterized by having.

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