JP2021190472A - Inductor and magnetic core for inductor - Google Patents

Abstract

To provide an inductor and a magnetic core for inductor, having an excellent characteristic in both of an inductance value and an insulation quality.SOLUTION: An inductor comprises: a magnetic powder containing a metal magnetic powder of a crystalline substance; a magnetic part having a resin; an element having a coil embedded into the magnetic part; and an external electrode arranged in the element. In a cross section of the element, when the magnetic powder contains a small particle of which radius of Haywood is 1 μm or smaller, a total area of the small particle is As, a total area of the magnetic powder is At, a small particle ratio As/At has a relation of 0.002≤As/At≤0.04. When the number of particles in which a circular degree coefficient of the magnetic powder exceeds 0.9 is Nr, and the total number of the magnetic powder is Nt, a sphere particle ratio Nr/Nt has a relation of 0.1≤Nr/Nt≤0.3. A sphere small particle ratio Rs defined by the following formula of the small particle ratio As/At ×the sphere particle ratio Nr/Nt ×10000 includes the relation of 3≤Rs≤33.SELECTED DRAWING: Figure 1

Description

本発明は、インダクタ及びインダクタ用磁芯に関する。 The present invention relates to an inductor and a magnetic core for an inductor.

磁性粉と樹脂を含有する素体内にコイルを埋設したインダクタが知られている。その中には、８Ｗｔ％以上１８ｗｔ％以下のＣｒを含有する金属磁性粉を用いて素体が形成されたインダクタが提案されている（例えば、特許文献１参照）。 An inductor in which a coil is embedded in an element body containing magnetic powder and resin is known. Among them, an inductor in which an element body is formed by using a metallic magnetic powder containing Cr of 8 Wt% or more and 18 wt% or less has been proposed (see, for example, Patent Document 1).

特開２００７−３５８２６号公報Japanese Unexamined Patent Publication No. 2007-35826

特許文献１に記載の従来のインダクタでは、金属磁性粉中のＣｒの量が増加するにつれて、絶縁性は向上するが、インダクタンス値が低下する傾向があった。 In the conventional inductor described in Patent Document 1, as the amount of Cr in the metallic magnetic powder increases, the insulating property tends to improve, but the inductance value tends to decrease.

本発明は、インダクタンス値及び絶縁性ともに優れた特性を有するインダクタ及びインダクタ用磁芯を提供することを目的とする。 An object of the present invention is to provide an inductor and a magnetic core for an inductor having excellent characteristics in terms of both inductance value and insulation.

本発明の１つの態様は、
結晶質の金属磁性粉を含有する磁性粉と、樹脂とを有する磁性部と、磁性部内に埋設されたコイルを有する素体と、素体に配置された外部電極を備えるインダクタであって、
素体の断面において、
磁性粉はヘイウッド径が１μｍ以下の小粒子を含み、
小粒子の合計面積をＡｓとし、磁性粉の総面積をＡｔとすると、
小粒子比率Ａｓ／Ａｔは、
０．００２ ≦ Ａｓ／Ａｔ ≦ ０．０４
の関係を有し、
磁性粉のうち円形度係数が０．９を超える粒子の個数をＮｒとし、磁性粉の総個数をＮｔとすると、
球形粒子比率Ｎｒ／Ｎｔは、
０．１ ≦ Ｎｒ／Ｎｔ ≦ ０．３
の関係を有し、
小粒子比率Ａｓ／Ａｔ×球形粒子比率Ｎｒ／Ｎｔ×１００００で定義される球形小粒子比率Ｒｓは、
３ ≦ Ｒｓ ≦ ３３
の関係を有する。 One aspect of the invention is
An inductor having a magnetic portion containing a magnetic powder containing crystalline metallic magnetic powder, a magnetic portion having a resin, an element body having a coil embedded in the magnetic part, and an external electrode arranged in the element body.
In the cross section of the element body
The magnetic powder contains small particles with a Haywood diameter of 1 μm or less.
Assuming that the total area of small particles is As and the total area of magnetic powder is At,
The small particle ratio As / At is
0.002 ≤ As / At ≤ 0.04
Have a relationship with
Assuming that the number of particles having a circularity coefficient exceeding 0.9 among the magnetic powders is Nr and the total number of magnetic powders is Nt, it is assumed.
The spherical particle ratio Nr / Nt is
0.1 ≤ Nr / Nt ≤ 0.3
Have a relationship with
The spherical small particle ratio Rs defined by the small particle ratio As / At × spherical particle ratio Nr / Nt × 10000 is
3 ≤ Rs ≤ 33
Have a relationship of.

本発明の別の１つの態様は、
結晶質の金属磁性粉を含有する磁性粉と、樹脂とを有するインダクタ用磁芯であって、
磁芯の断面において、
磁性粉はヘイウッド径が１μｍ以下の小粒子を含み、
小粒子の合計面積をＡｓとし、磁性粉の総面積をＡｔとすると、
小粒子比率Ａｓ／Ａｔは、
０．００２ ≦ Ａｓ／Ａｔ ≦ ０．０４
の関係を有し、
磁性粉のうち円形度係数が０．９を超える粒子の個数をＮｒとし、磁性粉の総個数をＮｔとすると、
球形粒子比率Ｎｒ／Ｎｔは、
０．１ ≦ Ｎｒ／Ｎｔ ≦ ０．３
の関係を有し、
小粒子比率Ａｓ／Ａｔ×球形粒子比率Ｎｒ／Ｎｔ×１００００で定義される球形小粒子比率Ｒｓは、
３ ≦ Ｒｓ ≦ ３３
の関係を有する。 Another aspect of the invention is
A magnetic core for an inductor having a magnetic powder containing crystalline metallic magnetic powder and a resin.
In the cross section of the magnetic core
The magnetic powder contains small particles with a Haywood diameter of 1 μm or less.
Assuming that the total area of small particles is As and the total area of magnetic powder is At,
The small particle ratio As / At is
0.002 ≤ As / At ≤ 0.04
Have a relationship with
Assuming that the number of particles having a circularity coefficient exceeding 0.9 among the magnetic powders is Nr and the total number of magnetic powders is Nt, it is assumed.
The spherical particle ratio Nr / Nt is
0.1 ≤ Nr / Nt ≤ 0.3
Have a relationship with
The spherical small particle ratio Rs defined by the small particle ratio As / At × spherical particle ratio Nr / Nt × 10000 is
3 ≤ Rs ≤ 33
Have a relationship of.

本発明の態様では、インダクタンス値及び絶縁性ともに優れた特性を有するインダクタ及びインダクタ用磁芯を提供することができる。 In the aspect of the present invention, it is possible to provide an inductor and a magnetic core for an inductor having excellent characteristics in both inductance value and insulating property.

本発明の第１の実施形態に係るインダクタを模式的に示す斜視図及び断面図である。It is a perspective view and sectional drawing which shows schematically the inductor which concerns on 1st Embodiment of this invention. 本発明の第２の実施形態に係るインダクタを模式的に示す斜視図である。It is a perspective view which shows typically the inductor which concerns on the 2nd Embodiment of this invention. 従来例のインダクタの素体又は磁芯の断面における磁性粉の小粒子及び大粒子の分布状態を模式的に示す図である。It is a figure which shows typically the distribution state of the small particle and the large particle of the magnetic powder in the cross section of the element body or the magnetic core of the inductor of the conventional example. 本発明の実施形態に係るインダクタの素体又は磁芯の断面における磁性粉の小粒子及び大粒子の分布状態を模式的に示す図である。It is a figure which shows typically the distribution state of the small particle and the large particle of the magnetic powder in the cross section of the element body or the magnetic core of the inductor which concerns on embodiment of this invention. 実施例における磁性粉の粒度分布を示すグラフである。It is a graph which shows the particle size distribution of the magnetic powder in an Example. 小粒子比率と透磁率と絶縁抵抗の関係を示すグラフである。It is a graph which shows the relationship between the small particle ratio, magnetic permeability, and insulation resistance. 球形粒子比率と透磁率と絶縁抵抗の関係を示すグラフである。It is a graph which shows the relationship between the spherical particle ratio, magnetic permeability, and insulation resistance. 球形小粒子比率と透磁率と絶縁抵抗の関係を示すグラフである。It is a graph which shows the relationship between the spherical small particle ratio, magnetic permeability, and insulation resistance.

以下、図面を参照しながら、本発明を実施するための実施形態を説明する。以下に説明する実施形態は、本発明の技術思想を具体化するためのものであって、特定的な記載がない限り、本発明を以下のものに限定しない。
各図面中、同一の機能を有する部材には、同一符号を付している場合がある。要点の説明または理解の容易性を考慮して、便宜上実施形態を分けて示す場合があるが、異なる実施形態で示した構成の部分的な置換または組み合わせは可能である。後述の実施形態では前述の実施形態と共通の事柄についての記述を省略し、異なる点についてのみ説明する。特に、同様の構成による同様の作用効果については、実施形態ごとには逐次言及しないものとする。各図面が示す部材の大きさや位置関係等は、説明を明確にするため、誇張して示している場合もある。 Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The embodiments described below are for embodying the technical idea of the present invention, and the present invention is not limited to the following unless otherwise specified.
In each drawing, members having the same function may be designated by the same reference numeral. Although the embodiments may be shown separately for convenience in consideration of the explanation of the main points or the ease of understanding, partial replacement or combination of the configurations shown in the different embodiments is possible. In the embodiment described later, the description of the matters common to the above-described embodiment will be omitted, and only the differences will be described. In particular, similar actions and effects with the same configuration will not be mentioned sequentially for each embodiment. The size and positional relationship of the members shown in each drawing may be exaggerated for the sake of clarity.

（第１の実施形態に係るインダクタ）
はじめに、図１を参照しながら、本発明の第１の実施形態に係るインダクタの説明を行う。図１は、本発明の第１の実施形態に係るインダクタを模式的に示す斜視図及び断面図である。更に詳細に述べれば、図１の（ａ）はインダクタの外形を示す斜視図であり、（ｂ）は、（ａ）のＡ−Ａ断面を示す断面図である。図１では、互いに直交する３方向を、ｘ軸、ｙ軸及びｚ軸で示している。後述する図２も同様である。 (Inductor according to the first embodiment)
First, the inductor according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a perspective view and a cross-sectional view schematically showing an inductor according to the first embodiment of the present invention. More specifically, FIG. 1A is a perspective view showing an outer shape of the inductor, and FIG. 1B is a cross-sectional view showing a cross section taken along the line AA of FIG. 1A. In FIG. 1, three directions orthogonal to each other are shown on the x-axis, y-axis, and z-axis. The same applies to FIG. 2, which will be described later.

本実施形態に係るインダクタ１は、外観形状が略直方体形状の素体２、及び素体２に配置された一対の外部電極４を備える。素体２は、コイル８及びコイル８を埋設する磁性部６を備える。また、一対の外部電極４は、素体２の両側に離間して配置されている。 The inductor 1 according to the present embodiment includes an element body 2 having a substantially rectangular parallelepiped external shape, and a pair of external electrodes 4 arranged on the element body 2. The element body 2 includes a coil 8 and a magnetic portion 6 in which the coil 8 is embedded. Further, the pair of external electrodes 4 are arranged apart from each other on both sides of the element body 2.

＜素体＞
素体２は、コイル８及び磁性部６により構成される。素体２は、外観形状が略直方体であり、ｘ軸方向が長手方向であり、ｙ軸方向が短手方向である。素体２は、底面２ａと、底面２ａに対向する上面２ｂと、短手方向（ｙ軸方向）に延在する側面２ｃ、２ｅと、長手方向（ｘ軸方向）に延在する側面２ｄ、２ｆとを有する。素体２の寸法として、長手方向（ｘ軸方向）の長さが０．５ｍｍ以上３．４ｍｍ以下、好ましくは１ｍｍ以上３ｍｍ以下であり、短手方向（ｙ軸方向）の長さが０．５ｍｍ以上２．７ｍｍ以下、好ましくは０．５ｍｍ以上２．５ｍｍ以下であり、高さ方向（ｚ軸方向）の長さが０．５ｍｍ以上２．０ｍｍ以下、好ましくは０．５ｍｍ以上１．５ｍｍ以下を例示することができるが、これに限られるものではない。 <Elementary body>
The element body 2 is composed of a coil 8 and a magnetic portion 6. The element body 2 has a substantially rectangular parallelepiped appearance, the x-axis direction is the longitudinal direction, and the y-axis direction is the lateral direction. The element body 2 has a bottom surface 2a, a top surface 2b facing the bottom surface 2a, side surfaces 2c and 2e extending in the lateral direction (y-axis direction), and side surfaces 2d extending in the longitudinal direction (x-axis direction). It has 2f and. The dimensions of the element 2 are such that the length in the longitudinal direction (x-axis direction) is 0.5 mm or more and 3.4 mm or less, preferably 1 mm or more and 3 mm or less, and the length in the lateral direction (y-axis direction) is 0. 5 mm or more and 2.7 mm or less, preferably 0.5 mm or more and 2.5 mm or less, and the length in the height direction (z-axis direction) is 0.5 mm or more and 2.0 mm or less, preferably 0.5 mm or more and 1.5 mm or less. The following can be exemplified, but the present invention is not limited thereto.

＜コイル＞
コイル８は、素体２の上面から見て長手方向（ｘ軸方向）に貫通する金属板で形成されている。本実施形態では、コイルの導体が重なることがないので、浮遊容量を低減することできる。コイル８を構成する金属板は、例えば銅等の導電性金属材料で形成される。コイルを構成する金属板は、厚みが例えば０．０５ｍｍ以上０．２ｍｍ以下、好ましくは０．１ｍｍ以上０．１５ｍｍ以下であり、短手方向の長さが例えば０．３ｍｍ以上１．０ｍｍ以下、好ましくは０．４５ｍｍ以上０．７５ｍｍ以下を例示することができるが、これに限られるものではない。 <Coil>
The coil 8 is formed of a metal plate penetrating in the longitudinal direction (x-axis direction) when viewed from the upper surface of the element body 2. In this embodiment, since the conductors of the coils do not overlap, the stray capacitance can be reduced. The metal plate constituting the coil 8 is formed of a conductive metal material such as copper. The metal plate constituting the coil has a thickness of, for example, 0.05 mm or more and 0.2 mm or less, preferably 0.1 mm or more and 0.15 mm or less, and a length in the lateral direction of, for example, 0.3 mm or more and 1.0 mm or less. Preferably, 0.45 mm or more and 0.75 mm or less can be exemplified, but the present invention is not limited thereto.

＜磁性部＞
磁性部６は、磁性粉及び樹脂を含有する。磁性部６の磁性粉は、結晶性の金属磁性粉、特に、結晶質のＦｅ−Ｓｉ−Ｃｒ金属磁性粉を用いるのが好ましい。Ｆｅ−Ｓｉ−Ｃｒ金属磁性粉は、Ｓｉが１〜５ｗｔ％、好ましくは３〜４ｗｔ％、更に好ましくは３〜３．５ｗｔ％含有し、Ｃｒが１〜７ｗｔ％、好ましくは４〜５ｗｔ％、更に好ましくは４．５〜５ｗｔ％含有し、残部がＦｅ及び不可避不純物からなる。このような組成により、金属磁性粉の透磁率を高くすることができる。 <Magnetic part>
The magnetic portion 6 contains a magnetic powder and a resin. As the magnetic powder of the magnetic portion 6, it is preferable to use a crystalline metallic magnetic powder, particularly a crystalline Fe—Si—Cr metallic magnetic powder. The Fe-Si-Cr metallic magnetic powder contains 1 to 5 wt%, preferably 3 to 4 wt%, more preferably 3 to 3.5 wt% of Si, and 1 to 7 wt%, preferably 4 to 5 wt% of Cr. More preferably, it contains 4.5 to 5 wt%, and the balance is composed of Fe and unavoidable impurities. With such a composition, the magnetic permeability of the metallic magnetic powder can be increased.

また、この金属磁性粉は、粒径が１μｍ以下（主に粒径が０．５〜１μｍ）の小粒子と、粒径がそれより大きい大粒子より構成される。大粒子及び小粒子の混合粒子の粒度分布における体積基準による累積５０％値であるＤ５０が、１〜５μｍ、好ましくは２〜４μｍ、更に好ましくは３〜４μｍである。また、この大粒子及び小粒子の混合粒子の粒度分布において、小粒子を構成する粒径０．５〜１μｍの体積頻度は、０．００１〜０．０４であることが好ましい。 Further, this metallic magnetic powder is composed of small particles having a particle size of 1 μm or less (mainly a particle size of 0.5 to 1 μm) and large particles having a larger particle size. The cumulative 50% value of D50 in the particle size distribution of the mixed particles of large particles and small particles is 1 to 5 μm, preferably 2 to 4 μm, and more preferably 3 to 4 μm. Further, in the particle size distribution of the mixed particles of the large particles and the small particles, the volume frequency of the particle size of 0.5 to 1 μm constituting the small particles is preferably 0.001 to 0.04.

更に、この金属磁性粉の表面のＣｒ量が０．５〜２．０ａｔ％、好ましくは０．５〜１．５ａｔ％、更に好ましくは１．０〜１．５ａｔ％である。金属磁性粉の表面に上記のような量のＣｒ有することより、後述の金属磁性粉表面の酸化被膜のＦｅの酸化物の量とＣｒの酸化物の量のバランスを保つことができ、金属磁性粉の絶縁抵抗を高めることができる。 Further, the amount of Cr on the surface of this metallic magnetic powder is 0.5 to 2.0 at%, preferably 0.5 to 1.5 at%, and more preferably 1.0 to 1.5 at%. By having the above amount of Cr on the surface of the metal magnetic powder, it is possible to maintain a balance between the amount of Fe oxide and the amount of Cr oxide in the oxide film on the surface of the metal magnetic powder described later, and the metal magnetism can be maintained. The insulation resistance of the powder can be increased.

また、金属磁性粉表面の酸化被膜が１０〜５０ｎｍ、好ましくは１０〜２５ｎｍ、更に好ましくは１０〜１５ｎｍである。酸化膜が、金属磁性粉のＦｅに由来するＦｅの酸化膜であることが好ましい。特に、金属磁性粉の表面に、Ｆｅの酸化物及びＣｒの酸化物を含む酸化膜が形成されていることが更に好ましい。これにより、金属磁性粉の絶縁抵抗を高めることができる。 The oxide film on the surface of the metal magnetic powder is 10 to 50 nm, preferably 10 to 25 nm, and more preferably 10 to 15 nm. The oxide film is preferably an oxide film of Fe derived from Fe of the metal magnetic powder. In particular, it is more preferable that an oxide film containing an oxide of Fe and an oxide of Cr is formed on the surface of the metallic magnetic powder. This makes it possible to increase the insulation resistance of the metallic magnetic powder.

以上のように、金属磁性粉の平均粒子径（Ｄ５０）が１〜５μｍであり、金属磁性粉の断面の外周に１０〜５０ｎｍの酸化被膜を有することが好ましい。これにより、素体２の高周波領域の透磁率を高くできるので、インダクタ１の高周波領域のインダクタンス値を大きくできる。 As described above, it is preferable that the metal magnetic powder has an average particle diameter (D50) of 1 to 5 μm and has an oxide film of 10 to 50 nm on the outer periphery of the cross section of the metal magnetic powder. As a result, the magnetic permeability in the high frequency region of the element body 2 can be increased, so that the inductance value in the high frequency region of the inductor 1 can be increased.

磁性部６の樹脂として、熱硬化性樹脂を用いるのが好ましい。熱硬化性樹脂としては、エポキシ樹脂、フェノール樹脂、ポリイミド樹脂、ビスマレイミド樹脂、ユリア（尿素）樹脂、メラミン樹脂、ポリウレタン樹脂、シアネートエステル樹脂、シリコーン樹脂、オキセタン樹脂（オキセタン化合物）、（メタ）アクリレート樹脂、不飽和ポリエステル樹脂、ジアリルフタレート樹脂、ベンゾオキサジン樹脂を例示することができる。これらを、２種以上併用して用いることもできる。 It is preferable to use a thermosetting resin as the resin of the magnetic portion 6. Examples of the thermosetting resin include epoxy resin, phenol resin, polyimide resin, bismaleimide resin, urea (urea) resin, melamine resin, polyurethane resin, cyanate ester resin, silicone resin, oxetan resin (oxetan compound), and (meth) acrylate. Examples thereof include resins, unsaturated polyester resins, diallyl phthalate resins, and benzoxazine resins. These can be used in combination of two or more.

また、磁性部６の樹脂として、ポリエチレン樹脂、ポリアミド樹脂、液晶ポリマー等の熱可塑性樹脂を用いることもできる。磁性部６における樹脂の含有量は、０．５ｗｔ％〜５．０ｗｔ％が好ましい。 Further, as the resin of the magnetic portion 6, a thermoplastic resin such as a polyethylene resin, a polyamide resin, and a liquid crystal polymer can also be used. The content of the resin in the magnetic portion 6 is preferably 0.5 wt% to 5.0 wt%.

＜外部電極＞
コイル８を形成する金属板は、その長手方向の両側で素体２の外部にまで延びており、外部電極４を形成している。素体２の外に露出した外部電極は、素体２に沿って底面に延在するように形成されている。図１の（ｂ）に示すように、一方の外部電極４は、素体２の側面２ｃ及び底面２ａに沿って配置され、他方の外部電極４は、素体２の側面２ｅ及び底面２ａに沿って配置されている。素体２の底面２ａにおいて、２つの外部電極４の端部は、十分な距離を開けて配置されている。 <External electrode>
The metal plate forming the coil 8 extends to the outside of the element body 2 on both sides in the longitudinal direction thereof, and forms the external electrode 4. The external electrode exposed to the outside of the element body 2 is formed so as to extend to the bottom surface along the element body 2. As shown in FIG. 1B, one external electrode 4 is arranged along the side surface 2c and the bottom surface 2a of the element body 2, and the other external electrode 4 is arranged on the side surface 2e and the bottom surface 2a of the element body 2. It is arranged along. On the bottom surface 2a of the element body 2, the ends of the two external electrodes 4 are arranged with a sufficient distance.

（第２の実施形態に係るインダクタ）
次に、図２を参照しながら、本発明の第２の実施形態に係るインダクタの説明を行う。図２は、本発明の第２の実施形態に係るインダクタを模式的に示す斜視図である。
第２の実施形態も、外観形状が略直方体の素体２を有するが、コイル８及び外部電極４の構造が第１の実施形態と異なる。 (Inductor according to the second embodiment)
Next, the inductor according to the second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a perspective view schematically showing an inductor according to a second embodiment of the present invention.
The second embodiment also has the element body 2 having a substantially rectangular parallelepiped appearance, but the structures of the coil 8 and the external electrode 4 are different from those of the first embodiment.

本実施形態のコイル８を形成する導線は、導体の表面に絶縁性を有する被覆層と、被覆層の表面に融着層を有する導線であって、互いに対向する一対の幅広面を有し、断面が矩形形状の導線（いわゆる、平角線）である。コイル８は、１本の導線が最内周で繋がった上段１２及び下段１４に巻回された巻回部１０と、巻回部１０の最外周から引き出された一対の引き出し部１６とを含んでおり、いわゆるα巻きコイルである。一対の引き出し部１６は、先端１６ａの幅広面が磁性部６から露出しており、それぞれ外部電極４と電気的に接続している。 The conductor forming the coil 8 of the present embodiment is a conductor having an insulating coating layer on the surface of the conductor and a fusion layer on the surface of the coating layer, and has a pair of wide surfaces facing each other. A conductor with a rectangular cross section (so-called flat wire). The coil 8 includes a winding portion 10 wound around an upper stage 12 and a lower stage 14 in which one conducting wire is connected at the innermost circumference, and a pair of drawing portions 16 drawn out from the outermost periphery of the winding portion 10. It is a so-called α-wound coil. In the pair of drawers 16, the wide surface of the tip 16a is exposed from the magnetic portion 6, and each of the pair of drawers 16 is electrically connected to the external electrode 4.

導線を構成する導体は、例えば銅等で形成される。被覆層は、ポリアミドイミド等の絶縁性樹脂で形成される。融着層は、巻回部１０を構成する導線同士を固定できる様に、自己融着成分を含む熱可塑性樹脂または熱硬化性樹脂等で形成さる。
巻回部１０は、上記の導線をその幅広面が巻軸Ａ１と略平行になるように巻回して形成されている。巻回部１０は、巻軸Ａ１が素体２の底面２ａと略直交するように素体２内に配置されている。引き出し部１６の先端１６ａは、その一方の幅広面が素体２の短手方向の側面２ｃ、２ｅに露出するように曲げられている。 The conductor constituting the conducting wire is made of, for example, copper or the like. The coating layer is formed of an insulating resin such as polyamide-imide. The fused layer is formed of a thermoplastic resin containing a self-bonding component, a thermosetting resin, or the like so that the conducting wires constituting the winding portion 10 can be fixed to each other.
The winding portion 10 is formed by winding the above-mentioned conducting wire so that its wide surface is substantially parallel to the winding shaft A1. The winding portion 10 is arranged in the element body 2 so that the winding axis A1 is substantially orthogonal to the bottom surface 2a of the element body 2. The tip 16a of the drawer portion 16 is bent so that one of the wide surfaces thereof is exposed to the side surfaces 2c and 2e of the element body 2 in the lateral direction.

一対の外部電極４は、素体２の表面に形成され、互いに離隔して配置されている。本実施形態では、一方の外部電極４は、素体２の短手方向の側面２ｃとそれに隣接する４つの面２ａ、２ｂ、２ｄ、２ｆの一部とを覆っており、磁性部６から露出した引き出し部１６の先端１６ａの幅広面と電気的に接続されている。また、他方の外部電極４は、素体２の側面２ｅとそれに隣接する４つの面２ａ、２ｂ、２ｄ、２ｆの一部とを覆っており、磁性部６から露出した引き出し部１６の先端１６ａの幅広面と電気的に接続されている。外部電極４は、例えば、金属粒子及び樹脂を含有する導電性樹脂により形成される。金属粒子として、例えば銀が用いられる。樹脂として、例えばエポキシ樹脂が用いられる。また、外部電極４は、金属粒子及び樹脂を含有する導電性樹脂上には、ニッケルから形成される第１層と、第１層上に形成され、スズから形成される第２層とを備えるめっき層が形成されてもよい。素体２の寸法としては、長手方向（ｘ軸方向）の長さが１．０ｍｍ以上４．０ｍｍ以下であり、短手方向（ｙ軸方向）の長さが０．５ｍｍ以上４．０ｍｍ以下であり、高さ方向（ｚ軸方向）の長さが０．５ｍｍ以上２．０ｍｍ以下を例示することができるが、これに限られるものではない。 The pair of external electrodes 4 are formed on the surface of the element body 2 and are arranged apart from each other. In the present embodiment, one of the external electrodes 4 covers the side surface 2c of the element body 2 in the lateral direction and a part of the four surfaces 2a, 2b, 2d, and 2f adjacent thereto, and is exposed from the magnetic portion 6. It is electrically connected to the wide surface of the tip 16a of the drawer portion 16. Further, the other external electrode 4 covers the side surface 2e of the element body 2 and a part of the four surfaces 2a, 2b, 2d, and 2f adjacent to the side surface 2e, and the tip 16a of the drawer portion 16 exposed from the magnetic portion 6. It is electrically connected to the wide surface of the. The external electrode 4 is formed of, for example, a conductive resin containing metal particles and a resin. As the metal particles, for example, silver is used. As the resin, for example, an epoxy resin is used. Further, the external electrode 4 includes a first layer formed of nickel and a second layer formed on the first layer and formed of tin on the conductive resin containing metal particles and resin. A plating layer may be formed. As for the dimensions of the element body 2, the length in the longitudinal direction (x-axis direction) is 1.0 mm or more and 4.0 mm or less, and the length in the lateral direction (y-axis direction) is 0.5 mm or more and 4.0 mm or less. The length in the height direction (z-axis direction) may be 0.5 mm or more and 2.0 mm or less, but the present invention is not limited to this.

磁性部６を形成する金属磁性粉及び樹脂については、上記の第１の実施形態と同様であり、更なる説明は省略する。 The metal magnetic powder and the resin forming the magnetic portion 6 are the same as those in the first embodiment described above, and further description thereof will be omitted.

（磁性粉の分布状態の測定）
磁性部の磁性粉の分布状態を測定するため、上記の実施形態に係るインダクタ１の素体２を長手方向に切断して、その断面を研磨することにより平滑な断面を得た。そして、走査電子顕微鏡(ＳＥＭ)を用いて、所定の倍率（例えば、５０００倍）でその視野に磁性粉の断面が１００個以上入るように３か所撮影して、素体の断面の画像を取得した。具体的には、第１の実施形態に係るインダクタでは、図１に示す様に、素体２の上面から見て金属板が埋設されている位置と対応する位置において、金属板の延在方向に沿って、素体の長手方向に延在する平滑な断面を得、図１の（ｂ）に示す点線で囲まれた領域を撮影することにより素体の断面の画像を取得した。第２の実施形態に係るインダクタでは、図２に示す様に、素体２において、コイルの巻軸を含んで、素体の長手方向に延在する平滑な断面を得、素体の断面のコイルの巻軸領域を撮影することにより素体の断面の画像を取得した。 (Measurement of distribution of magnetic powder)
In order to measure the distribution state of the magnetic powder in the magnetic portion, the element body 2 of the inductor 1 according to the above embodiment was cut in the longitudinal direction and the cross section thereof was polished to obtain a smooth cross section. Then, using a scanning electron microscope (SEM), photographs are taken at three locations so that 100 or more cross sections of the magnetic powder are contained in the field of view at a predetermined magnification (for example, 5000 times), and an image of the cross section of the element body is taken. Obtained. Specifically, in the inductor according to the first embodiment, as shown in FIG. 1, the extending direction of the metal plate is at a position corresponding to the position where the metal plate is embedded when viewed from the upper surface of the element body 2. A smooth cross section extending in the longitudinal direction of the element body was obtained along the above, and an image of the cross section of the element body was obtained by photographing the area surrounded by the dotted line shown in FIG. 1 (b). In the inductor according to the second embodiment, as shown in FIG. 2, in the element body 2, a smooth cross section extending in the longitudinal direction of the element body including the winding shaft of the coil is obtained, and the cross section of the element body is obtained. An image of the cross section of the element body was acquired by photographing the winding axis region of the coil.

そして、既知の画像解析式粒度分布ソフトウエアを用いて、撮影視野内の磁性粉の全粒子のヘイウッド径を測定して、磁性粉の平均粒子径を求めた。次に、画像解析式粒度分布ソフトウエアを用いて、撮影視野内における磁性粉のヘイウッド径が１μｍ以下の粒子を小粒子とし、その他の粒子（基本的に粒径が１μｍより大きい粒子）を大粒子とした。そして、小粒子の合計面積Ａｓを算出し、撮影視野内の全磁性粉の合計面積Ａｔを算出し、撮影視野内の全磁性粉の合計面積に対する小粒子の合計面積の割合である小粒子比率Ａｓ／Ａｔを算出した。 Then, using a known image analysis type particle size distribution software, the Haywood diameter of all the particles of the magnetic powder in the photographing field was measured, and the average particle size of the magnetic powder was obtained. Next, using image analysis type particle size distribution software, particles with a Haywood diameter of 1 μm or less in the imaging field are made small particles, and other particles (basically particles with a particle size larger than 1 μm) are made large. It was made into particles. Then, the total area As of the small particles is calculated, the total area At of the total magnetic powder in the photographing field is calculated, and the small particle ratio which is the ratio of the total area of the small particles to the total area of the total magnetic powder in the photographing field. As / At was calculated.

また、画像解析式粒度分布ソフトウエアを用いて、撮影視野内における全磁性粉について円形度係数を算出し、円形度係数が０．９を超える粒子の個数Ｎｒを算出した。そして、磁性粉の総個数Ｎｔを算出して、撮影視野内の全磁性粉の個数に対する円形度係数が０．９を超える磁性粉の個数の割合である球形粒子比率Ｎｒ／Ｎｔを算出した。
なお、一般的に、溶融した金属に高圧のガスや水を吹き付けて凝固させるアトマイズ法で金属磁性粉を作成するが、温度条件、吹付量、吹付圧力等を調整することにより、形成される磁性粉の球形度を調整することができる。 Further, using the image analysis type particle size distribution software, the circularity coefficient was calculated for all the magnetic powders in the photographing field, and the number Nr of particles having the circularity coefficient exceeding 0.9 was calculated. Then, the total number of magnetic powders Nt was calculated, and the spherical particle ratio Nr / Nt, which is the ratio of the number of magnetic powders having a circularity coefficient of more than 0.9 to the total number of magnetic powders in the imaging field, was calculated.
Generally, metal magnetic powder is produced by an atomizing method in which high-pressure gas or water is sprayed onto a molten metal to solidify it, but the magnetism formed by adjusting the temperature conditions, spraying amount, spraying pressure, etc. The sphericality of the powder can be adjusted.

更に、小粒子比率Ａｓ／Ａｔ×球形粒子比率Ｎｒ／Ｎｔ×１００００で定義される球形小粒子比率Ｒｓを算出した。これらの値に基づく金属磁性粉の分布状態及びインダクタの特性について、以下に検討を行う。 Further, the spherical small particle ratio Rs defined by the small particle ratio As / At × spherical particle ratio Nr / Nt × 10000 was calculated. The distribution of metallic magnetic powder and the characteristics of the inductor based on these values will be examined below.

（磁性粉の分布状態に関する検討）
次に、図３及び図４を参照しながら、磁性粉の小粒子及び大粒子の分布状態とインダクタの特性との関係について検討を行う。図３は、従来例のインダクタの素体又は磁芯の断面における磁性粉の小粒子及び大粒子の分布状態を模式的に示す図である。図４は、本発明の実施形態に係るインダクタの素体又は磁芯の断面における磁性粉の小粒子及び大粒子の分布状態を模式的に示す図である。黒色の円または楕円が小粒子を示し、白色の円または楕円が大粒子を示す。 (Examination of distribution of magnetic powder)
Next, with reference to FIGS. 3 and 4, the relationship between the distribution state of the small particles and the large particles of the magnetic powder and the characteristics of the inductor will be examined. FIG. 3 is a diagram schematically showing the distribution state of small particles and large particles of magnetic powder in the cross section of the element body or the magnetic core of the conventional inductor. FIG. 4 is a diagram schematically showing the distribution state of small particles and large particles of magnetic powder in the cross section of the element body or magnetic core of the inductor according to the embodiment of the present invention. A black circle or ellipse indicates a small particle, and a white circle or ellipse indicates a large particle.

小粒子比率Ａｓ／Ａｔが小さい場合、つまり小粒子が少ない場合には、図３の（ａ）に示すように、素体又は磁芯内において、大粒子の間に存在する小粒子の量が少ないので、磁性粉の充填率が低くなる。よって、素体又は磁芯の透磁率も低下し、延いてはインダクタのインダクタンス値も低下する。一方、小粒子比率Ａｓ／Ａｔが大きすぎる場合には、図３の（ｃ）に示すように、素体又は磁芯内において、大粒子の間に存在する小粒子の量が過多となり、小粒子が凝集し、素体又は磁芯の絶縁性が低下する虞がある。 When the small particle ratio As / At is small, that is, when the number of small particles is small, as shown in FIG. 3 (a), the amount of small particles existing between the large particles in the element body or the magnetic core is Since the amount is small, the filling rate of the magnetic powder is low. Therefore, the magnetic permeability of the element body or the magnetic core also decreases, and the inductance value of the inductor also decreases. On the other hand, when the small particle ratio As / At is too large, as shown in FIG. 3 (c), the amount of small particles existing between the large particles in the element body or the magnetic core becomes excessive and small. Particles may aggregate and the insulating property of the element or magnetic core may decrease.

球形粒子比率Ｎｒ／Ｎｔが小さい場合、つまり、いびつな形状の磁性粉が多い場合には、図３の（ｂ）に示すように、素体又は磁芯内において、いびつな形状の磁性粉の突出部分と隣接する磁性粉間の間隔が狭くなる、磁性粉間の間隔の偏りの発生領域が大きくなり、球形粒子比率Ｎｒ／Ｎｔが大きすぎる場合には、素体又は磁芯内において、磁性粉間の間隔が大きくなり、インダクタンス値と絶縁性のバランスを取ることが困難となる。 When the spherical particle ratio Nr / Nt is small, that is, when there are many distorted magnetic powders, as shown in FIG. 3B, the distorted magnetic powders in the element or core. When the distance between the protruding portion and the adjacent magnetic powder becomes narrow, the region where the gap between the magnetic powders is unevenly generated becomes large, and the spherical particle ratio Nr / Nt is too large, the magnetism in the element body or the magnetic core The distance between the powders becomes large, and it becomes difficult to balance the inductance value and the insulating property.

球形小粒子比率Ｒｓが小さい場合も、球形小粒子比率Ｒｓが大きすぎる場合も、素体又は磁芯内において、大粒子と小粒子の配置に偏りが発生しやすくなり、インダクタンス値と絶縁性のバランスを取ることが困難となる。 When the spherical small particle ratio Rs is small or the spherical small particle ratio Rs is too large, the arrangement of large particles and small particles tends to be biased in the element body or the magnetic core, and the inductance value and the insulating property are increased. It becomes difficult to balance.

以上のように、十分な絶縁性を有するとともに、素体又は磁芯の透磁率を高め、延いてはインダクタのインダクタンス値を向上させるため、小粒子比率Ａｓ／Ａｔ、球形粒子比率Ｎｒ／Ｎｔ及び球形小粒子比率Ｒｓの全ての項目について、適切な範囲内に収めることが重要である。
小粒子比率Ａｓ／Ａｔ、球形粒子比率Ｎｒ／Ｎｔ及び球形小粒子比率Ｒｓを適切な範囲内に収めることにより、製造中の樹脂中において大粒子及び小粒子の状態に偏りをなくすことができ、図４に示すように、素体又は磁芯内において、大粒子と小粒子の配置に偏りがなくなり、磁性粉間の間隔の偏りもなくなる。また、素体の樹脂及び金属磁性粉の合計の重量に対する、金属磁性粉の重量を大きくできるので、素体又は磁芯の透磁率を向上させ、インダクタのインダクタンス値を向上させることができる。 As described above, in order to have sufficient insulating properties, increase the magnetic permeability of the element or magnetic core, and further improve the inductance value of the inductor, the small particle ratio As / At, the spherical particle ratio Nr / Nt and It is important to keep all items of the spherical small particle ratio Rs within an appropriate range.
By keeping the small particle ratio As / At, the spherical particle ratio Nr / Nt, and the spherical small particle ratio Rs within appropriate ranges, it is possible to eliminate the bias in the state of large particles and small particles in the resin being manufactured. As shown in FIG. 4, there is no bias in the arrangement of large particles and small particles in the element body or the magnetic core, and there is no bias in the spacing between the magnetic powders. Further, since the weight of the metal magnetic powder can be increased with respect to the total weight of the resin and the metal magnetic powder of the element body, the magnetic permeability of the element body or the magnetic core can be improved and the inductance value of the inductor can be improved.

（実施例）
小粒子比率Ａｓ／Ａｔ、球形粒子比率Ｎｒ／Ｎｔ及び球形小粒子比率Ｒｓの適切な範囲を見出すため、異なる組成の磁性体を試作して、透磁率及び絶縁性の測定を行った。詳細を下記に示す。 (Example)
In order to find an appropriate range of the small particle ratio As / At, the spherical particle ratio Nr / Nt and the spherical small particle ratio Rs, magnetic materials having different compositions were prototyped and the magnetic permeability and the insulating property were measured. Details are shown below.

金属磁性粉として、結晶質のＦｅ−Ｓｉ−Ｃｒ金属磁性粉である試料Ａ、Ｂ及びＣを準備した。試料Ａ、Ｂ及びＣの体積基準粒度分布を測定したところ、図５に示すような粒度分布が示された。図５は、実施例における金属磁性粉の粒度分布を示すグラフである。試料Ａ、Ｂ及びＣの何れも、粒径が３μｍ近傍をピークとする粒度分布を有する。試料Ａ、Ｂ及びＣの粒度分布における累積１０％値をＤ１０、累積５０％値をＤ５０、累積９０％値をＤ９０とすると、下記の表１に示すような値となった。また、粒径が１μｍ以下の小粒子の累積％も、表１に示すようになった。 As the metallic magnetic powder, samples A, B and C, which are crystalline Fe-Si-Cr metallic magnetic powder, were prepared. When the volume-based particle size distributions of Samples A, B and C were measured, the particle size distribution as shown in FIG. 5 was shown. FIG. 5 is a graph showing the particle size distribution of the metallic magnetic powder in the examples. All of the samples A, B and C have a particle size distribution having a particle size peaking in the vicinity of 3 μm. Assuming that the cumulative 10% value in the particle size distribution of the samples A, B, and C is D10, the cumulative 50% value is D50, and the cumulative 90% value is D90, the values are as shown in Table 1 below. In addition, the cumulative percentage of small particles having a particle size of 1 μm or less is also shown in Table 1.

［表１］

[Table 1]

材料Ａ、Ｂ及びＣの組成を、ＩＣＰ発光分光分析（ＩＣＰ−ＡＥＳ：ＩＣＰ−Ａｔｏｍｉｃ Ｅｍｉｓｓｉｏｎ Ｓｐｅｃｔｒｏｍｅｔｒｙ）やＸ線光電子分光（ＸＰＳ：Ｘ−ｒａｙ ｐｈｏｔｏｅｌｅｃｔｒｏｎ ｓｐｅｃｔｒｏｓｃｏｐｙ）を用いて解析したところ、下記の表２及び表３示す結果が得られた。 The compositions of materials A, B and C were analyzed using ICP-AES (ICP-Atomic Measurement Spectroscopy) and X-ray photoelectron spectroscopy (XPS: X-ray photoelectron spectroscopy), and the results are shown in Table 2 below. And the results shown in Table 3 were obtained.

［表２］ ［ａｔ％］

[Table 2] [at%]

［表３］ ［ａｔ％］

[Table 3] [at%]

また、この材料Ａ、Ｂ及びＣの金属磁性粉の表面のＣｒ量を測定したところ、それぞれ、１．２ａｔ％、０．５ａｔ％、１．７ａｔ％であった。さらに、この材料Ａ、Ｂ及びＣの酸化膜厚を測定したところ、材料Ａ、Ｂは１０〜１５ｎｍ、材料Ｃは５〜１０ｎｍであった。 以上のような金属磁性粉の材料Ａ、Ｂ及びＣに対して、それぞれ２．５ｗｔ％の樹脂を加え、金型を使用し、１０ｔで加圧、成型して、それぞれインダクタの素体又は磁芯を作成した。
そして、それぞれの素体又は磁芯の断面の磁性粉の分布状態を測定したところ表４に示す結果が得られた。 Further, when the amount of Cr on the surface of the metallic magnetic powders of the materials A, B and C was measured, they were 1.2 at%, 0.5 at% and 1.7 at%, respectively. Further, when the oxide film thicknesses of the materials A, B and C were measured, it was found that the materials A and B had a thickness of 10 to 15 nm and the material C had a thickness of 5 to 10 nm. 2.5 wt% of resin is added to each of the above metal magnetic powder materials A, B and C, and a mold is used to pressurize and mold at 10 tons to form an inductor core or magnetic core, respectively. I made a core.
Then, when the distribution state of the magnetic powder in the cross section of each element body or magnetic core was measured, the results shown in Table 4 were obtained.

材料Ｂを用いた試料１では、素体又は磁芯の断面の画像を取得し、既知の画像解析式粒度分布ソフトウエアを用いて、撮影視野内の磁性粉の全粒子のヘイウッド径を測定して、磁性粉の平均粒子径を求めたところ、磁性粉の平均粒子径は３．２μｍとなり、小粒子比率Ａｓ／Ａｔ、球形粒子比率Ｎｒ／Ｎｔ、球形小粒子比率Ｒｓを算出したところ、小粒子比率Ａｓ／Ａｔが０．００１、球形粒子比率Ｎｒ／Ｎｔが０．１８、球形小粒子比率Ｒｓが１．８となった。また、素体又は磁芯の断面に露出した金属磁性粉の断面の外周に、１０〜１５ｎｍの厚みの酸化膜が形成されていた。 In the sample 1 using the material B, an image of a cross section of the element body or the magnetic core is acquired, and the Haywood diameter of all the particles of the magnetic powder in the photographing field is measured by using a known image analysis type particle size distribution software. When the average particle size of the magnetic powder was obtained, the average particle size of the magnetic powder was 3.2 μm, and when the small particle ratio As / At, the spherical particle ratio Nr / Nt, and the spherical small particle ratio Rs were calculated, they were small. The particle ratio As / At was 0.001, the spherical particle ratio Nr / Nt was 0.18, and the spherical small particle ratio Rs was 1.8. Further, an oxide film having a thickness of 10 to 15 nm was formed on the outer periphery of the cross section of the metal magnetic powder exposed on the cross section of the element body or the magnetic core.

また、材料Ａを用いた試料２では、素体又は磁芯の断面の画像を取得し、既知の画像解析式粒度分布ソフトウエアを用いて、撮影視野内の磁性粉の全粒子のヘイウッド径を測定して、磁性粉の平均粒子径を求めたところ、磁性粉の平均粒子径は３．２μｍとなり、小粒子比率Ａｓ／Ａｔ、球形粒子比率Ｎｒ／Ｎｔ、球形小粒子比率Ｒｓを算出したところ、小粒子比率Ａｓ／Ａｔが０．００７、球形粒子比率Ｎｒ／Ｎｔが０．１８、球形小粒子比率Ｒｓが１２．６となった。また、素体又は磁芯の断面に露出した金属磁性粉の断面の外周に、１０〜１５ｎｍの厚みの酸化膜が形成されていた。 Further, in the sample 2 using the material A, an image of a cross section of the element body or the magnetic core is acquired, and a known image analysis type particle size distribution software is used to determine the Haywood diameter of all the particles of the magnetic powder in the photographing field. When the average particle size of the magnetic powder was obtained by measurement, the average particle size of the magnetic powder was 3.2 μm, and the small particle ratio As / At, the spherical particle ratio Nr / Nt, and the spherical small particle ratio Rs were calculated. The small particle ratio As / At was 0.007, the spherical particle ratio Nr / Nt was 0.18, and the spherical small particle ratio Rs was 12.6. Further, an oxide film having a thickness of 10 to 15 nm was formed on the outer periphery of the cross section of the metal magnetic powder exposed on the cross section of the element body or the magnetic core.

さらに、材料Ｃを用いた試料３では、素体又は磁芯の断面の画像を取得し、既知の画像解析式粒度分布ソフトウエアを用いて、撮影視野内の磁性粉の全粒子のヘイウッド径を測定して、磁性粉の平均粒子径を求めたところ、磁性粉の平均粒子径は３．２μｍとなり、小粒子比率Ａｓ／Ａｔ、球形粒子比率Ｎｒ／Ｎｔ、球形小粒子比率Ｒｓを算出したところ、小粒子比率Ａｓ／Ａｔが０．０４６、球形粒子比率Ｎｒ／Ｎｔが０．０８、球形小粒子比率Ｒｓが３６．８となった。また、素体又は磁芯の断面に露出した金属磁性粉の断面の外周に、５〜１０ｎｍの厚みの酸化膜が形成されていた。 Further, in the sample 3 using the material C, an image of a cross section of the element body or the magnetic core is acquired, and a known image analysis type particle size distribution software is used to determine the Haywood diameter of all the particles of the magnetic powder in the photographing field. When the average particle size of the magnetic powder was obtained by measurement, the average particle size of the magnetic powder was 3.2 μm, and the small particle ratio As / At, the spherical particle ratio Nr / Nt, and the spherical small particle ratio Rs were calculated. The small particle ratio As / At was 0.046, the spherical particle ratio Nr / Nt was 0.08, and the spherical small particle ratio Rs was 36.8. Further, an oxide film having a thickness of 5 to 10 nm was formed on the outer periphery of the cross section of the metal magnetic powder exposed on the cross section of the element body or the magnetic core.

［表４］

[Table 4]

この試料１、２、３で得られた測定結果に基づくと、小粒子比率Ａｓ／Ａｔ、球形粒子比率Ｎｒ／Ｎｔ及び球形小粒子比率Ｒｓと透磁率と絶縁抵抗の間で、図６から図８に示すような関係を有することが明らかになった。図６は、小粒子比率と透磁率と絶縁抵抗の関係を示すグラフであり、図７は、球形粒子比率と透磁率と絶縁抵抗の関係を示すグラフであり、図８は、球形小粒子比率と透磁率との関係を示すグラフである。なお、図６から図８において、実線は透磁率の特性、点線は絶縁抵抗の特性を示す。 Based on the measurement results obtained in Samples 1, 2 and 3, the small particle ratio As / At, the spherical particle ratio Nr / Nt, the spherical small particle ratio Rs, the magnetic permeability and the insulation resistance are shown in FIGS. 6 to 6. It was revealed that they have the relationship shown in 8. FIG. 6 is a graph showing the relationship between the small particle ratio, magnetic permeability and insulation resistance, FIG. 7 is a graph showing the relationship between spherical particle ratio, magnetic permeability and insulation resistance, and FIG. 8 is a spherical small particle ratio. It is a graph which shows the relationship between and magnetic permeability. In FIGS. 6 to 8, solid lines show the characteristics of magnetic permeability, and dotted lines show the characteristics of insulation resistance.

図６に示すように、透磁率は、小粒子比率Ａｓ／Ａｔの値が０．００１の時１９．５であったものが、小粒子比率Ａｓ／Ａｔの値が０．００２の時２０、小粒子比率Ａｓ／Ａｔの値が０．００７の時２２．４と増加し、小粒子比率Ａｓ／Ａｔの値が０．０４６の時２４まで増加した。絶縁抵抗は、小粒子比率Ａｓ／Ａｔの値が０．００１の時６．５ＭΩ／ｍｍあったものが、小粒子比率Ａｓ／Ａｔの値が０．００７の時２．３９ＭΩ／ｍｍと低下し、小粒子比率Ａｓ／Ａｔの値が０．０４の時０．４ＭΩ／ｍｍ、小粒子比率Ａｓ／Ａｔの値が０．０４６の時０．０４ＭΩ／ｍｍまで低下した。従って、小粒子比率Ａｓ／Ａｔの値が０．００２よりも小さくなると透磁率が２０未満となって、所定のインダクタンス値が得られなくなり、小粒子比率Ａｓ／Ａｔの値が０．０４よりも大きくなると絶縁抵抗が０．４ＭΩ／ｍｍ未満となって、端子間にショートが発生した。 As shown in FIG. 6, the magnetic permeability was 19.5 when the small particle ratio As / At value was 0.001, but 20 when the small particle ratio As / At value was 0.002. When the value of the small particle ratio As / At was 0.007, it increased to 22.4, and when the value of the small particle ratio As / At was 0.046, it increased to 24. The insulation resistance was 6.5 MΩ / mm when the small particle ratio As / At value was 0.001, but decreased to 2.39 MΩ / mm when the small particle ratio As / At value was 0.007. When the value of the small particle ratio As / At was 0.04, it decreased to 0.4 MΩ / mm, and when the value of the small particle ratio As / At was 0.046, it decreased to 0.04 MΩ / mm. Therefore, when the value of the small particle ratio As / At is smaller than 0.002, the magnetic permeability becomes less than 20, and a predetermined inductance value cannot be obtained, and the value of the small particle ratio As / At is larger than 0.04. When it became large, the insulation resistance became less than 0.4 MΩ / mm, and a short circuit occurred between the terminals.

また、図７に示すように、透磁率は、球形粒子比率Ｎｒ／Ｎｔの値が０．０８の時２４であったものが、球形粒子比率Ｎｒ／Ｎｔの値が０．１８の時２２．４、球形粒子比率Ｎｒ／Ｎｔの値が０．３の時２０と低下し、球形粒子比率Ｎｒ／Ｎｔの値が０．３よりも大きくなると２０未満になった。絶縁抵抗は、球形粒子比率Ｎｒ／Ｎｔの値が０．０８の時０．０４ＭΩ／ｍｍだったものが、球形粒子比率Ｎｒ／Ｎｔの値が０．１の時０．４ＭΩ／ｍｍ、球形粒子比率Ｎｒ／Ｎｔの値が０．１８の時２．３９ＭΩ／ｍｍ、球形粒子比率Ｎｒ／Ｎｔの値が５ＭΩ／ｍｍと大きくなった。従って、球形粒子比率Ｎｒ／Ｎｔの値が０．１よりも小さくなると絶縁抵抗が０．４ＭΩ／ｍｍ未満となって、端子間にショートが発生し、球形粒子比率Ｎｒ／Ｎｔの値が０．３よりも大きくなると透磁率が２０未満となって、所定のインダクタンス値が得られなくなった。 Further, as shown in FIG. 7, the magnetic permeability was 24 when the value of the spherical particle ratio Nr / Nt was 0.08, but 22. When the value of the spherical particle ratio Nr / Nt was 0.18. 4. When the value of the spherical particle ratio Nr / Nt was 0.3, it decreased to 20, and when the value of the spherical particle ratio Nr / Nt was larger than 0.3, it became less than 20. The insulation resistance was 0.04 MΩ / mm when the value of the spherical particle ratio Nr / Nt was 0.08, but 0.4 MΩ / mm when the value of the spherical particle ratio Nr / Nt was 0.1, spherical particles. When the value of the ratio Nr / Nt was 0.18, the value was 2.39 MΩ / mm, and the value of the spherical particle ratio Nr / Nt was as large as 5 MΩ / mm. Therefore, when the value of the spherical particle ratio Nr / Nt becomes smaller than 0.1, the insulation resistance becomes less than 0.4 MΩ / mm, a short circuit occurs between the terminals, and the value of the spherical particle ratio Nr / Nt becomes 0. When it becomes larger than 3, the magnetic permeability becomes less than 20, and a predetermined inductance value cannot be obtained.

さらに、図８に示すように、透磁率は、球形小粒子比率Ｒｓの値が１．８の時１９．５であったものが、球形小粒子比率Ｒｓの値が３の時２０、球形小粒子比率Ｒｓの値が１２．６の時２２．４と増加し、球形小粒子比率Ｒｓの値が３６の時２４まで増加した。絶縁抵抗は、球形小粒子比率Ｒｓの値が１．８の時６．５６ＭΩ／ｍｍだったものが、球形小粒子比率Ｒｓの値が１２．６の時２．３９ＭΩ／ｍｍ、球形小粒子比率Ｒｓの値が３３の時０．４ＭΩ／ｍｍ、球形小粒子比率Ｒｓの値が３６．８の時０．０４ＭΩ／ｍｍと低下した。従って、球形小粒子比率Ｒｓの値が３よりも小さくなると透磁率が２０未満となって、所定のインダクタンス値が得られなくなり、球形小粒子比率Ｒｓの値が３３よりも大きくなると絶縁抵抗が０．４ＭΩ／ｍｍ未満となって、端子間にショートが発生した。 Further, as shown in FIG. 8, the magnetic permeability was 19.5 when the value of the spherical small particle ratio Rs was 1.8, but was 20 when the value of the spherical small particle ratio Rs was 3, and the spherical small particle ratio was small. When the value of the particle ratio Rs was 12.6, it increased to 22.4, and when the value of the spherical small particle ratio Rs was 36, it increased to 24. The insulation resistance was 6.56 MΩ / mm when the value of the spherical small particle ratio Rs was 1.8, but 2.39 MΩ / mm when the value of the spherical small particle ratio Rs was 12.6, and the spherical small particle ratio. When the value of Rs was 33, it decreased to 0.4 MΩ / mm, and when the value of spherical small particle ratio Rs was 36.8, it decreased to 0.04 MΩ / mm. Therefore, when the value of the spherical small particle ratio Rs becomes smaller than 3, the magnetic permeability becomes less than 20, and a predetermined inductance value cannot be obtained. When the value of the spherical small particle ratio Rs becomes larger than 33, the insulation resistance becomes 0. It was less than .4 MΩ / mm, and a short circuit occurred between the terminals.

以上を考慮すると、小粒子比率Ａｓ／Ａｔの値が０．００２以上０．０４以下の範囲にあり、球形粒子比率Ｎｒ／Ｎｔの値が０．１以上０．３以下の範囲にあり、かつ球形小粒子比率Ｒｓが３以上３３以下の範囲にある場合には、十分な絶縁性を有するとともに、素体又は磁芯の透磁率が向上し、延いてはインダクタンス値が向上することが明らかになった。 Considering the above, the value of the small particle ratio As / At is in the range of 0.002 or more and 0.04 or less, the value of the spherical particle ratio Nr / Nt is in the range of 0.1 or more and 0.3 or less, and It is clear that when the spherical small particle ratio Rs is in the range of 3 or more and 33 or less, it has sufficient insulating properties, the magnetic permeability of the element or the magnetic core is improved, and the inductance value is improved. became.

従って、素体又は磁芯の断面において、磁性粉はヘイウッド径が１μｍ以下の小粒子を含み、小粒子の合計面積をＡｓとし、磁性粉の総面積をＡｔとすると、小粒子比率Ａｓ／Ａｔは、０．００２ ≦ Ａｓ／Ａｔ ≦ ０．０４の関係を有し、磁性粉のうち円形度係数が０．９を超える粒子の個数をＮｒとし、磁性粉の総個数をＮｔとすると、球形粒子比率Ｎｒ／Ｎｔは、０．１ ≦ Ｎｒ／Ｎｔ ≦ ０．３の関係を有し、小粒子比率Ａｓ／Ａｔ×球形粒子比率Ｎｒ／Ｎｔ×１００００で定義される球形小粒子比率Ｒｓは、３ ≦ Ｒｓ ≦ ３３の関係を有する場合には、インダクタンス値及び絶縁性ともに優れた特性を得ることができる。 Therefore, in the cross section of the element body or the magnetic core, if the magnetic powder contains small particles having a Haywood diameter of 1 μm or less, the total area of the small particles is As, and the total area of the magnetic powder is At, the small particle ratio As / At. Has a relationship of 0.002 ≤ As / At ≤ 0.04, and if the number of particles having a circularity coefficient exceeding 0.9 among the magnetic powders is Nr and the total number of magnetic powders is Nt, it is spherical. The particle ratio Nr / Nt has a relationship of 0.1 ≤ Nr / Nt ≤ 0.3, and the spherical small particle ratio Rs defined by the small particle ratio As / At × spherical particle ratio Nr / Nt × 10000 is When the relationship of 3 ≤ Rs ≤ 33 is obtained, excellent characteristics of both the inductance value and the insulating property can be obtained.

以上、本発明の実施形態及び実施例を説明したが、開示内容は構成の細部において変化してもよく、実施形態及び実施例における要素の組合せや順序の変化等は請求された本発明の範囲及び思想を逸脱することなく実現し得るものである。
例えば、インダクタは、結晶質の金属磁性粉を含有する磁性粉と、樹脂とでトロイダル形状、ドラム形状に形成された磁芯に導線を巻回して形成されてもよく、このインダクタ用磁芯は、磁芯の断面において、磁性粉はヘイウッド径が１μｍ以下の小粒子を含み、小粒子の合計面積をＡｓとし、磁性粉の総面積をＡｔとすると、小粒子比率Ａｓ／Ａｔは、
０．００２ ≦ Ａｓ／Ａｔ ≦ ０．０４の関係を有し、磁性粉のうち円形度係数が０．９を超える粒子の個数をＮｒとし、磁性粉の総個数をＮｔとすると、球形粒子比率Ｎｒ／Ｎｔは、０．１ ≦ Ｎｒ／Ｎｔ ≦ ０．３の関係を有し、小粒子比率Ａｓ／Ａｔ×球形粒子比率Ｎｒ／Ｎｔ×１００００で定義される球形小粒子比率Ｒｓは、３ ≦ Ｒｓ ≦ ３３の関係を有する。 Although the embodiments and examples of the present invention have been described above, the disclosed contents may be changed in the details of the configuration, and changes in the combination and order of the elements in the embodiments and the examples are the scope of the claimed invention. And it can be realized without deviating from the idea.
For example, the inductor may be formed by winding a lead wire around a magnetic core formed in a toroidal shape or a drum shape by a magnetic powder containing a crystalline metallic magnetic powder and a resin, and the magnetic core for the inductor may be formed. In the cross section of the magnetic core, if the magnetic powder contains small particles having a Haywood diameter of 1 μm or less, the total area of the small particles is As, and the total area of the magnetic powder is At, the small particle ratio As / At is.
Assuming that the number of particles having a relationship of 0.002 ≤ As / At ≤ 0.04 and the circularity coefficient exceeds 0.9 among the magnetic powders is Nr and the total number of magnetic powders is Nt, the spherical particle ratio. Nr / Nt has a relationship of 0.1 ≤ Nr / Nt ≤ 0.3, and the spherical small particle ratio Rs defined by the small particle ratio As / At × spherical particle ratio Nr / Nt × 10000 is 3 ≦. It has a relationship of Rs ≤ 33.

１ インダクタ
２ 素体
２ａ 底面
２ｂ 上面
２ｃ、２ｄ、２ｅ、２ｆ 側面
４ 外部電極
６ 磁性部
８ コイル
１０ 巻回部
１２ 上段
１４ 下段
１６ 引き出し部
１６ａ 先端 1 Inductor 2 Element 2a Bottom surface 2b Top surface 2c, 2d, 2e, 2f Side surface 4 External electrode 6 Magnetic part 8 Coil 10 Winding part 12 Upper stage 14 Lower stage 16 Drawer part 16a Tip

Claims (7)

結晶質の金属磁性粉を含有する磁性粉と、樹脂とを有する磁性部と、磁性部内に埋設されたコイルを有する素体と、前記素体に配置された外部電極を備えるインダクタであって、
前記素体の断面において、
前記磁性粉はヘイウッド径が１μｍ以下の小粒子を含み、
前記小粒子の合計面積をＡｓとし、前記磁性粉の総面積をＡｔとすると、
小粒子比率Ａｓ／Ａｔは、
０．００２ ≦ Ａｓ／Ａｔ ≦ ０．０４
の関係を有し、
前記磁性粉のうち円形度係数が０．９を超える粒子の個数をＮｒとし、前記磁性粉の総個数をＮｔとすると、
球形粒子比率Ｎｒ／Ｎｔは、
０．１ ≦ Ｎｒ／Ｎｔ ≦ ０．３
の関係を有し、
前記小粒子比率Ａｓ／Ａｔ×前記球形粒子比率Ｎｒ／Ｎｔ×１００００で定義される球形小粒子比率Ｒｓは、
３ ≦ Ｒｓ ≦ ３３
の関係を有することを特徴とするインダクタ。
An inductor having a magnetic powder containing a crystalline metallic magnetic powder, a magnetic portion having a resin, an element body having a coil embedded in the magnetic part, and an external electrode arranged in the element body.
In the cross section of the element body
The magnetic powder contains small particles having a Haywood diameter of 1 μm or less.
Assuming that the total area of the small particles is As and the total area of the magnetic powder is At.
The small particle ratio As / At is
0.002 ≤ As / At ≤ 0.04
Have a relationship with
Let Nr be the number of particles having a circularity coefficient of more than 0.9 among the magnetic powders, and let Nt be the total number of the magnetic powders.
The spherical particle ratio Nr / Nt is
0.1 ≤ Nr / Nt ≤ 0.3
Have a relationship with
The spherical small particle ratio Rs defined by the small particle ratio As / At × the spherical particle ratio Nr / Nt × 10000 is
3 ≤ Rs ≤ 33
An inductor characterized by having the relationship of.
前記金属磁性粉の表面に、Ｆｅの酸化物及びＣｒの酸化物を含む酸化膜が形成されている請求項１に記載のインダクタ。
The inductor according to claim 1, wherein an oxide film containing an oxide of Fe and an oxide of Cr is formed on the surface of the metallic magnetic powder.
前記金属磁性粉の平均粒子径が１〜５μｍであり、前記金属磁性粉の断面の外周に１０〜５０ｎｍの酸化被膜を有する請求項１又は請求項２に記載のインダクタ。
The inductor according to claim 1 or 2, wherein the metal magnetic powder has an average particle diameter of 1 to 5 μm and has an oxide film of 10 to 50 nm on the outer periphery of the cross section of the metal magnetic powder.
前記素体は、底面と、底面に対向する上面と、短手方向に延在する側面と、長手方向に延在する側面とを有し、
前記コイルは、前記素体の上面から見て長手方向に貫通する金属板で形成される請求項１に記載のインダクタ。
The element body has a bottom surface, an upper surface facing the bottom surface, a side surface extending in the lateral direction, and a side surface extending in the longitudinal direction.
The inductor according to claim 1, wherein the coil is formed of a metal plate penetrating in the longitudinal direction when viewed from the upper surface of the element body.
結晶質の金属磁性粉を含有する磁性粉と、樹脂とを有するインダクタ用磁芯であって、
前記磁芯の断面において、
前記磁性粉はヘイウッド径が１μｍ以下の小粒子を含み、
前記小粒子の合計面積をＡｓとし、前記磁性粉の総面積をＡｔとすると、
小粒子比率Ａｓ／Ａｔは、
０．００２ ≦ Ａｓ／Ａｔ ≦ ０．０４
の関係を有し、
前記磁性粉のうち円形度係数が０．９を超える粒子の個数をＮｒとし、前記磁性粉の総個数をＮｔとすると、
球形粒子比率Ｎｒ／Ｎｔは、
０．１ ≦ Ｎｒ／Ｎｔ ≦ ０．３
の関係を有し、
前記小粒子比率Ａｓ／Ａｔ×前記球形粒子比率Ｎｒ／Ｎｔ×１００００で定義される球形小粒子比率Ｒｓは、
３ ≦ Ｒｓ ≦ ３３
の関係を有することを特徴とするインダクタ用磁芯。
A magnetic core for an inductor having a magnetic powder containing crystalline metallic magnetic powder and a resin.
In the cross section of the magnetic core
The magnetic powder contains small particles having a Haywood diameter of 1 μm or less.
Assuming that the total area of the small particles is As and the total area of the magnetic powder is At.
The small particle ratio As / At is
0.002 ≤ As / At ≤ 0.04
Have a relationship with
Let Nr be the number of particles having a circularity coefficient of more than 0.9 among the magnetic powders, and let Nt be the total number of the magnetic powders.
The spherical particle ratio Nr / Nt is
0.1 ≤ Nr / Nt ≤ 0.3
Have a relationship with
The spherical small particle ratio Rs defined by the small particle ratio As / At × the spherical particle ratio Nr / Nt × 10000 is
3 ≤ Rs ≤ 33
A magnetic core for an inductor, which is characterized by having a relationship of.
前記金属磁性粉の表面に、Ｆｅの酸化物及びＣｒの酸化物を含む酸化膜が形成されている請求項５に記載のインダクタ用磁芯。
The magnetic core for an inductor according to claim 5, wherein an oxide film containing an oxide of Fe and an oxide of Cr is formed on the surface of the metal magnetic powder.
前記金属磁性粉の平均粒子径が１〜５μｍであり、前記金属磁性粉の断面の外周に１０〜５０ｎｍの酸化被膜を有する請求項５又は請求項６に記載のインダクタ用磁芯。 The magnetic core for an inductor according to claim 5 or 6, wherein the metal magnetic powder has an average particle diameter of 1 to 5 μm and has an oxide film of 10 to 50 nm on the outer periphery of the cross section of the metal magnetic powder.

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