JP2022102391A

JP2022102391A - Inductor

Info

Publication number: JP2022102391A
Application number: JP2020217089A
Authority: JP
Inventors: 武士小林; Takeshi Kobayashi
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 2020-12-25
Filing date: 2020-12-25
Publication date: 2022-07-07

Abstract

To provide an inductor which allows enhancement in insulation resistance between external electrodes and portions, in a winding part of a coil, having a potential significantly different from that of lead-out parts, thereby improving voltage withstanding capability between the winding part of the coil and the external electrodes.SOLUTION: An inductor 1 comprises: an element body 2 which has a magnetic part 6 containing magnetic powder and a coil 8 at least partially embedded in the magnetic part 6, and which has two principal surfaces 2a, 2b and lateral surfaces adjacent to the two principal surfaces 2a, 2b; and a pair of external electrodes 4A, 4B which is formed at least on one of the principal surfaces 2a, 2b of the element body, and which is connected to the coil 8. The coil 8 has: a winding part 10 which is formed by winding, on upper and lower two stages, a conductor wire having an insulation coating in such a manner that its both ends are located on the outermost circumference; and a pair of lead-out parts 16A, 16B which is led out from the outermost circumference of the upper stage 12 and the lower stage 14 so as to be connected to the external electrodes 4A, 4B. When viewed through from the principal surfaces 2a, 2b side of the element body, there are formed insulator parts 20 on the insulation coating on surfaces, of the winding part 10, which face the external electrodes 4A, 4B.SELECTED DRAWING: Figure 3

Description

本発明は、磁性部にコイル埋設されたインダクタに関する。 The present invention relates to an inductor in which a coil is embedded in a magnetic portion.

磁性粉と樹脂とを含む磁性部に、導線が巻回されたコイルが埋設されたインダクタが知られている。そのようなインダクタの中には、断面が矩形状の導線を上段及び下段の２段に巻回されたコイルであって、２つの段が最内周に位置する導線で繋がっており、かつそれぞれの段が最外周に導線の端部を有する、所謂、α巻きのコイルを用い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 in which a conducting wire is wound is embedded in a magnetic portion containing magnetic powder and a resin is known. In such an inductor, a conductor having a rectangular cross section is wound in two stages, an upper stage and a lower stage, and the two stages are connected by a conductor wire located at the innermost circumference, and each of them is connected. There has been proposed an inductor using a so-called α-wound coil in which the stage has an end of a conducting wire on the outermost periphery (see, for example, Patent Document 1).

特開２０１６－１７１３４９号JP-A-2016-171349

所謂α巻きコイルでは、巻回部において、引き出し部との間に電位差が大きい部分が存在する。インダクタの小型化の要請に伴い、コイルの巻回部における引き出し部との間の電位差が大きい部分と、外部電極とが近接し易くなっている。この様な状況で、導線の被膜に絶縁抵抗が低い材料を使用した場合、コイルの巻回部と、外部電極との間において絶縁抵抗が低くなる虞がある。よって、コイルの巻回部と外部電極との間の耐圧が低いという問題が生じる。 In the so-called α-wound coil, there is a portion in the winding portion where the potential difference is large between the winding portion and the drawing portion. With the demand for miniaturization of the inductor, the portion where the potential difference between the winding portion of the coil and the drawing portion is large and the external electrode are easily brought close to each other. In such a situation, when a material having a low insulating resistance is used for the coating of the conducting wire, the insulating resistance may be low between the winding portion of the coil and the external electrode. Therefore, there arises a problem that the withstand voltage between the coil winding portion and the external electrode is low.

本発明の１つの態様は、コイルの巻回部と、外部電極との間において、絶縁抵抗を高くすることができ、コイルの巻回部及び外部電極間の耐圧を向上させることができるインダクタを提供することを目的とする。 One aspect of the present invention is an inductor capable of increasing the insulation resistance between the coil winding portion and the external electrode and improving the withstand voltage between the coil winding portion and the external electrode. The purpose is to provide.

本発明の１つの態様は、
磁性粉を含有する磁性部と、少なくとも一部が磁性部内に埋設されたコイルとを有し、２つの主面及び２つの主面に隣接する側面を有する素体と、
素体の少なくとも１つの主面に形成された一対の外部電極と、
を備え、
コイルは、
絶縁被膜を有する導線をその両端が最外周に位置する様に、上下２段に巻回して形成される巻回部と、
上段及び下段の最外周から引き出され、外部電極に接続される一対の引き出し部と、
を有し、
素体の主面から透視したとき、巻回部の外部電極と対向する面の絶縁被膜上に絶縁体部が形成されているインダクタである。 One aspect of the invention is
A prime field having a magnetic portion containing magnetic powder and a coil having at least a part embedded in the magnetic portion, and having two main surfaces and side surfaces adjacent to the two main surfaces.
A pair of external electrodes formed on at least one main surface of the prime field,
Equipped with
The coil is
A winding portion formed by winding a conducting wire having an insulating coating in two upper and lower stages so that both ends are located on the outermost circumference.
A pair of drawers drawn from the outermost circumferences of the upper and lower tiers and connected to external electrodes,
Have,
An inductor in which an insulator portion is formed on an insulating coating on a surface facing the external electrode of the winding portion when viewed from the main surface of the prime field.

上記態様によれば、素体の主面から透視したときに、コイルの巻回部の外部電極と対向する面の絶縁被膜上に形成された絶縁体部により、コイルの巻回部と外部電極との間の絶縁抵抗を高くすることができる。 According to the above aspect, when viewed from the main surface of the prime field, the coil winding portion and the external electrode are formed by the insulator portion formed on the insulating coating on the surface facing the external electrode of the coil winding portion. Insulation resistance between and can be increased.

従って、本発明のインダクタは、コイルの巻回部と、外部電極との間において絶縁抵抗を高くすることができ、コイルの巻回部及び外部電極間の耐圧を向上させることができる。 Therefore, the inductor of the present invention can increase the insulation resistance between the coil winding portion and the external electrode, and can improve the withstand voltage between the coil winding portion and the external electrode.

本発明の第１の実施形態に係るインダクタを示す斜視図である。It is a perspective view which shows the inductor which concerns on 1st Embodiment of this invention. 図１に示すインダクタを素体の主面から透視して示した平面図である。FIG. 3 is a plan view showing the inductor shown in FIG. 1 as seen through from the main surface of the prime field. 図２の断面Ａ－Ａを模式的に示す断面図である。It is sectional drawing which shows typically the sectional AA of FIG. 本発明の第２の実施形態に係るインダクタを素体の主面から透視して示した平面図である。FIG. 3 is a plan view showing the inductor according to the second embodiment of the present invention as seen through from the main surface of the prime field. 図４の断面Ｂ－Ｂを模式的に示す断面図である。It is sectional drawing which shows typically the cross-section BB of FIG. 本発明の第３の実施形態に係るインダクタを模式的に示す側面断面図である。It is a side sectional view schematically showing the inductor which concerns on 3rd Embodiment of this invention.

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。要点の説明又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又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から図３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の概要を示す斜視図である。図２は、図１に示すインダクタを素体の主面から透視して示した平面図である。透視した部材を点線で示している。図３は、図２の断面Ａ－Ａを模式的に示す断面図である。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。後述する各図も同様である。
図１に示すように、本実施形態に係るインダクタ１は、素体２と、素体２の上に配置された一対の外部電極４Ａ、４Ｂとを備える。素体２は、コイル８と、コイル８を埋設する磁性部６とを備える。 (Inductor according to the first embodiment)
First, the inductor according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view showing an outline of an inductor according to a first embodiment of the present invention. FIG. 2 is a plan view showing the inductor shown in FIG. 1 as seen through from the main surface of the prime field. The see-through member is shown by a dotted line. FIG. 3 is a cross-sectional view schematically showing the cross sections AA of FIG. In FIG. 1, three directions orthogonal to each other are shown on the x-axis, y-axis, and z-axis. The same applies to each figure described later.
As shown in FIG. 1, the inductor 1 according to the present embodiment includes a prime field 2 and a pair of external electrodes 4A and 4B arranged on the prime field 2. The prime field 2 includes a coil 8 and a magnetic portion 6 in which the coil 8 is embedded.

（コイル）
コイル８は、銅線と、銅線を被覆する絶縁被膜を有する断面が矩形状の導線（所謂、平角線）をその両端が最外周に位置する様に、巻軸Ｊの周りに上下２段に巻回して形成される巻回部１０と、巻回部１０の上段及び下段の最外周からそれぞれ引き出されて外部電極４Ａ、４Ｂに接続される一対の引き出し部１６Ａ、１６Ｂとを備えている。所謂、α巻のコイルである。 (coil)
The coil 8 has a copper wire and a conductor wire having a rectangular cross section (so-called flat wire) having an insulating coating covering the copper wire, and has two upper and lower stages around the winding shaft J so that both ends thereof are located on the outermost periphery. It is provided with a winding portion 10 formed by winding the winding portion 10 and a pair of drawing portions 16A and 16B drawn from the outermost outer periphery of the upper and lower stages of the winding portion 10 and connected to the external electrodes 4A and 4B, respectively. .. It is a so-called α-winding coil.

コイルを形成する導線は、断面の長辺が、例えば、０．１～０．２２ｍｍであり、断面の短辺が０．０３～０．１２ｍｍである。絶縁被膜がポリイミド樹脂で形成される。巻回部１０の大きさは、外径が１．３～１．７ｍｍ、内径が０．５～０．８ｍｍ、高さが０．２～０．５ｍｍに形成される。 The conductor forming the coil has, for example, a long side of a cross section of 0.1 to 0.22 mm and a short side of a cross section of 0.03 to 0.12 mm. The insulating film is formed of a polyimide resin. The size of the winding portion 10 is formed so that the outer diameter is 1.3 to 1.7 mm, the inner diameter is 0.5 to 0.8 mm, and the height is 0.2 to 0.5 mm.

巻回部１０は、下段１４から一方の引き出し部１６Ａが引き出されており、上段１２からは他方の引き出し部１６Ｂが引き出されている。引き出し部１６Ａ、１６Ｂの先端１６Ａａ、１６Ｂａは、後述する磁性部６から露出している。 In the winding portion 10, one drawer portion 16A is pulled out from the lower stage 14, and the other drawer portion 16B is pulled out from the upper stage 12. The tips 16Aa and 16Ba of the drawer portions 16A and 16B are exposed from the magnetic portion 6 described later.

（磁性部）
磁性部６は、磁性粉と樹脂を含有し、２つの主面２ａ、２ｂ及び２つの主面２ａ、２ｂに隣接する４つの側面２ｃ～２ｆを有する。特に、実装面側の主面を底面２ｂと称し、底面２ｂに対向する主面を上面２ａと称する。主面２ａ、２ｂにほぼ直交して対向する４つの側面２ｃ～２ｆのうち、引き出し部１６Ａ、１６Ｂの先端１６Ａａ、１６Ｂａが露出している２つの側面を特に端面２ｃ、２ｅと称する。
この磁性部６は、コイル８の巻軸Jが実装面２ｂとほぼ直交し、引き出し部１６Ａ、１６Ｂの先端１６Ａａ、Ｂａが端面２ｃ、２ｅに露出する様に、コイル８が埋設されて素体２が形成される。素体２の大きさは、例えば、縦が２ｍｍ、横が１．２ｍｍ、高さが０．６～１ｍｍに形成される。 (Magnetic part)
The magnetic portion 6 contains magnetic powder and resin, and has two main surfaces 2a and 2b and four side surfaces 2c to 2f adjacent to the two main surfaces 2a and 2b. In particular, the main surface on the mounting surface side is referred to as a bottom surface 2b, and the main surface facing the bottom surface 2b is referred to as an upper surface 2a. Of the four side surfaces 2c to 2f facing the main surfaces 2a and 2b substantially orthogonally to each other, the two side surfaces on which the tips 16Aa and 16Ba of the drawer portions 16A and 16B are exposed are particularly referred to as end surfaces 2c and 2e.
In this magnetic portion 6, the coil 8 is embedded so that the winding shaft J of the coil 8 is substantially orthogonal to the mounting surface 2b and the tips 16Aa and Ba of the drawing portions 16A and 16B are exposed on the end surfaces 2c and 2e. 2 is formed. The size of the prime field 2 is formed, for example, to be 2 mm in length, 1.2 mm in width, and 0.6 to 1 mm in height.

磁性部６は、磁性粉と樹脂の混合物を加圧成形して形成される。混合物における磁性粉の充填率は、例えば、６０重量％以上であり、好ましくは８０重量％以上である。磁性粉としては、Ｆｅ、Ｆｅ－Ｓｉ、Ｆｅ－Ｓｉ－Ｃｒ、Ｆｅ－Ｓｉ－Ａｌ、Ｆｅ－Ｎｉ、Ｆｅ－Ｎｉ－Ａｌ、Ｆｅ－Ｎｉ－Ｍｏ、Ｆｅ－Ｃｒ－Ａｌ等の鉄系の金属磁性粉、他の組成系の金属磁性粉、アモルファス等の金属磁性粉、表面がガラス等の絶縁体で被覆された金属磁性粉、表面を改質した金属磁性粉、ナノレベルの微小な金属磁性粉末が用いられる。樹脂としては、エポキシ樹脂、ポリイミド樹脂、フェノール樹脂等の熱硬化性樹脂又は、ポリエチレン樹脂、ポリアミド樹脂等の熱可塑性樹脂が用いられる。 The magnetic portion 6 is formed by pressure molding a mixture of magnetic powder and resin. The filling rate of the magnetic powder in the mixture is, for example, 60% by weight or more, preferably 80% by weight or more. The magnetic powder includes iron-based metals such as Fe, Fe-Si, Fe-Si-Cr, Fe-Si-Al, Fe-Ni, Fe-Ni-Al, Fe-Ni-Mo, and Fe-Cr-Al. Magnetic powder, metal magnetic powder of other composition system, metal magnetic powder such as amorphous, metal magnetic powder whose surface is coated with an insulator such as glass, metal magnetic powder with modified surface, nano-level minute metal magnetism Powder is used. As the resin, a thermosetting resin such as an epoxy resin, a polyimide resin or a phenol resin, or a thermoplastic resin such as a polyethylene resin or a polyamide resin is used.

（外部電極）
本実施形態では、素体２の端面２ｃ、２ｅと端面に隣接する４つの面２ａ、２ｄ、２ｂ、２ｆに跨って外部電極４Ａ、４Ｂが形成される。一方の外部電極４Ａは、素体２の端面２ｃとそれに隣接する４つの面である上面２ａ、底面２ｂ、側面２ｄ、２ｆの一部を覆っている。このとき、外部電極４Ａの上面２ａ、底面２ｂに延在している部分は、素体２内に巻軸Jが底面２ｂとほぼ直交するコイルの巻回部１０の上下面との間に対向する面を有する様に形成される。この外部電極４Ａは、素体２の端面２ｃにおいて磁性部６から露出した一方の引き出し部１６Ａの先端１６Ａａと電気的に接続している。また、他方の外部電極４Ｂは、素体２の端面２ｅとそれに隣接する４つの面である上面２ａ、底面２ｂ、側面２ｄ、２ｆの一部を覆っている。このとき、外部電極４Ｂの上面２ａ、底面２ｂに延在している部分は、素体２内に巻軸Jが底面２ｂとほぼ直交するコイルの巻回部１０の上下面との間に対向する面を有する様に形成される。この外部電極４Ｂは、素体の端面２ｅにおいて磁性部６から露出した他方の引き出し部１６Ｂの先端１６Ｂａと電気的に接続している。 (External electrode)
In the present embodiment, the external electrodes 4A and 4B are formed straddling the end faces 2c and 2e of the prime field 2 and the four faces 2a, 2d, 2b and 2f adjacent to the end faces. One of the external electrodes 4A covers a part of the end surface 2c of the prime field 2 and four surfaces adjacent to the end surface 2a, the bottom surface 2b, the side surfaces 2d, and 2f. At this time, the portion extending to the upper surface 2a and the bottom surface 2b of the external electrode 4A faces the upper and lower surfaces of the winding portion 10 of the coil whose winding axis J is substantially orthogonal to the bottom surface 2b in the prime field 2. It is formed so as to have a surface to be formed. The external electrode 4A is electrically connected to the tip 16Aa of one of the drawers 16A exposed from the magnetic portion 6 on the end surface 2c of the prime field 2. Further, the other external electrode 4B covers a part of the end surface 2e of the prime field 2 and the four surfaces adjacent to the end surface 2e, the upper surface 2a, the lower surface 2b, and the side surfaces 2d and 2f. At this time, the portions extending to the upper surface 2a and the bottom surface 2b of the external electrode 4B face each other between the upper and lower surfaces of the winding portion 10 of the coil whose winding axis J is substantially orthogonal to the bottom surface 2b in the prime field 2. It is formed so as to have a surface to be formed. The external electrode 4B is electrically connected to the tip 16Ba of the other extraction portion 16B exposed from the magnetic portion 6 on the end surface 2e of the prime field.

外部電極４Ａ、４Ｂは、例えば、金属粒子と樹脂を含有する導電性樹脂により形成される。金属粒子は銀が用いられる。樹脂はエポキシ樹脂が用いられる。また、外部電極４Ａ、４Ｂは、導電性樹脂上に、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。 The external electrodes 4A and 4B are formed of, for example, a conductive resin containing metal particles and a resin. Silver is used as the metal particles. Epoxy resin is used as the resin. Further, in the external electrodes 4A and 4B, a plating layer having a first layer formed of nickel and a second layer formed on the first layer and formed of tin is formed on the conductive resin. May be good.

（絶縁体部）
次に、図２及び図３を参照しながら本実施形態に係るインダクタ１に備えられた絶縁体部の説明を行う。本実施形態では、導線を２段にα巻きしているため、コイル８の巻回部１０において、引き出し部１６Ａ、１６Ｂとの間に電位差が大きい部分が存在する。例えば、図３において、巻回部１０の上段１２の外周側の電位Ａと、巻回部１０の下段１４から引き出された一方の引き出し部１６Ａの電位Ｂとの間には大きな電位差を有する。また、一方の引き出し部１６Ａと接続された外部電極４Ａの電位Ｂ’は、一方の引き出し部１６Ａの電位Ｂに近似した値となる。よって、電位Ａである巻回部１０の上段１２の外周側と、電位Ｂ’である外部電極４Ａの間の領域Ｓ１は、両側に大きな電位差を有する。 (Insulator part)
Next, the insulator portion provided in the inductor 1 according to the present embodiment will be described with reference to FIGS. 2 and 3. In the present embodiment, since the conducting wire is α-wound in two stages, there is a portion of the winding portion 10 of the coil 8 where the potential difference is large between the drawing portions 16A and 16B. For example, in FIG. 3, there is a large potential difference between the potential A on the outer peripheral side of the upper 12 of the winding portion 10 and the potential B of one of the drawing portions 16A drawn from the lower 14 of the winding portion 10. Further, the potential B'of the external electrode 4A connected to one of the drawers 16A has a value close to the potential B of one of the drawers 16A. Therefore, the region S1 between the outer peripheral side of the upper stage 12 of the winding portion 10 having the potential A and the external electrode 4A having the potential B'has a large potential difference on both sides.

インダクタ１の小型化の要請に伴い領域Ｓ１がより小さくなると、上段１２の外周側と外部電極４Ａとの間の絶縁抵抗が低下する可能性がある。そこで、本実施形態では、巻回部１０の上段１２の外部電極４Ａと対向する面に絶縁体部２０が形成されている。絶縁体部２０は、図２に示すように、素体２の主面２ａ側から透視したとき（つまり、素体２の主面の平面視において）、巻回部１０の外周から長さＬまでの範囲において、巻回部１０の外部電極４Ａの内面と対向する面に形成されている。また、絶縁体部２０は厚みＴを有する。巻回部１０の上段１２の外周側が、最も外部電極４Ａとの電位差が大きくなり、内周側にいくにつれて電位差は小さくなっていく。 If the region S1 becomes smaller due to the request for miniaturization of the inductor 1, the insulation resistance between the outer peripheral side of the upper stage 12 and the external electrode 4A may decrease. Therefore, in the present embodiment, the insulator portion 20 is formed on the surface of the winding portion 10 on the upper stage 12 facing the external electrode 4A. As shown in FIG. 2, the insulator portion 20 has a length L from the outer circumference of the winding portion 10 when viewed from the main surface 2a side of the prime field 2 (that is, in a plan view of the main surface of the prime field 2). In the range up to, it is formed on the surface of the winding portion 10 facing the inner surface of the external electrode 4A. Further, the insulator portion 20 has a thickness T. The outer peripheral side of the upper 12 of the winding portion 10 has the largest potential difference with the external electrode 4A, and the potential difference becomes smaller toward the inner peripheral side.

同様に、図３において、巻回部１０の下段１４の外周側の電位Ｃと、巻回部１０の上段１２から引き出された他方の引き出し部１６Ｂの電位Ｄとの間には大きな電位差を有する。また、他方の引き出し部１６Ｂと接続された外部電極４Ｂの電位Ｄ’は、他方の引き出し部１６Ｂの電位Ｄに近似した値となる。よって、電位Ｃである巻回部１０の下段１４の外周側と、電位Ｄ’である外部電極４Ｂとの間の領域Ｓ２は、両側に大きな電位差を有する。
このため、巻回部１０の下段１４の外部電極４Ｂと対向する面に絶縁体部２０が形成されている。絶縁体部２０は、上記と同様に、素体２の主面２ｂ側から透視したとき、巻回部１０の外周から長さＬまでの範囲において形成され、厚みＴを有する。 Similarly, in FIG. 3, there is a large potential difference between the potential C on the outer peripheral side of the lower 14 of the winding portion 10 and the potential D of the other drawing portion 16B drawn from the upper 12 of the winding portion 10. .. Further, the potential D'of the external electrode 4B connected to the other drawing portion 16B has a value close to the potential D of the other drawing portion 16B. Therefore, the region S2 between the outer peripheral side of the lower 14 of the winding portion 10 having the potential C and the external electrode 4B having the potential D'has a large potential difference on both sides.
Therefore, the insulator portion 20 is formed on the surface of the lower stage 14 of the winding portion 10 facing the external electrode 4B. Similar to the above, the insulator portion 20 is formed in a range from the outer periphery of the winding portion 10 to the length L when viewed from the main surface 2b side of the prime field 2, and has a thickness T.

長さＬは、外部電極４Ａと対向する面の最大領域である図２の太字点線で囲まれた部分Ｐの全域まで伸ばすことができる。絶縁体部２０は、ポリウレタン樹脂で形成される。例えば、製造したコイル８の巻回部１０の外面の所定の部分に上記の絶縁材料を塗布することにより、絶縁体部２０を形成することができる。また、絶縁体部２０は、ポリウレタン樹脂の他にも、ポリエステル樹脂、ポリイミド樹脂、エポキシ樹脂の中から選択して用いることができる。さらに、絶縁体部２０は、ポリウレタン樹脂、ポリエステル樹脂、ポリイミド樹脂、エポキシ樹脂の中から複数組み合わせて用いることもできる。また、絶縁体部２０は、導線の絶縁被膜と異なる材質で形成されるが、導線の絶縁被膜と同じ材質で形成しても良い。さらに、絶縁体部２０は、磁性部を構成する樹脂と異なる材質で形成される。 The length L can be extended to the entire area of the portion P surrounded by the bold dotted line in FIG. 2, which is the maximum region of the surface facing the external electrode 4A. The insulator portion 20 is made of polyurethane resin. For example, the insulator portion 20 can be formed by applying the above-mentioned insulating material to a predetermined portion of the outer surface of the wound portion 10 of the manufactured coil 8. Further, the insulator portion 20 can be used by selecting from polyester resin, polyimide resin, and epoxy resin in addition to polyurethane resin. Further, the insulator portion 20 can be used in combination of a plurality of polyurethane resin, polyester resin, polyimide resin, and epoxy resin. Further, although the insulator portion 20 is formed of a material different from the insulating coating of the conducting wire, it may be formed of the same material as the insulating coating of the conducting wire. Further, the insulator portion 20 is formed of a material different from the resin constituting the magnetic portion.

以上のように、本実施形態では、図３に示すように、素体２の主面２ａ、２ｂ側から透視したとき、巻回部１０の外部電極４Ａ、４Ｂと対向する面（太字点線で囲まれた部分）Ｐの少なくとも一部に絶縁体部２０が形成されている。絶縁体部２０により、コイル８の巻回部１０における引き出し部１６Ａ、１６Ｂとの間の電位差が大きい部分と、外部電極４との間において絶縁抵抗を高くすることができ、コイル８の巻回部１０と外部電極４との間の耐圧を向上させることができる。
塗布により、巻回部１０の外面に絶縁体部２０を形成する場合、素体２の主面２ａ、２ｂ側から透視した場合、コイル８の巻回部１０の外部電極４と対向する面において、巻回部１０の少なくとも外周が厚く形成されていると言うことができる。 As described above, in the present embodiment, as shown in FIG. 3, the surfaces (in bold dotted lines) facing the external electrodes 4A and 4B of the winding portion 10 when viewed from the main surfaces 2a and 2b of the prime field 2. An insulator portion 20 is formed in at least a part of the enclosed portion) P. The insulator portion 20 can increase the insulation resistance between the portion of the winding portion 10 of the coil 8 where the potential difference between the drawing portions 16A and 16B is large and the external electrode 4, and the winding of the coil 8 can be increased. The withstand voltage between the portion 10 and the external electrode 4 can be improved.
When the insulator portion 20 is formed on the outer surface of the winding portion 10 by coating, when viewed from the main surfaces 2a and 2b of the prime field 2, on the surface of the coil 8 facing the external electrode 4 of the winding portion 10. It can be said that at least the outer periphery of the winding portion 10 is thickly formed.

特に、図３に示すように、巻回部１０の引き出し部が引き出された段１４（１２）と反対側の段１２（１４）の外部電極４Ａ、４Ｂと対向する面に絶縁体部２０が形成することにより、効果的に巻回部１０と外部電極４との間の耐圧を向上させることができる。 In particular, as shown in FIG. 3, the insulator portion 20 is provided on the surface of the step 12 (14) opposite to the step 14 (12) from which the drawing portion of the winding portion 10 is pulled out and facing the external electrodes 4A and 4B. By forming it, the withstand voltage between the winding portion 10 and the external electrode 4 can be effectively improved.

巻回部１０の引き出し部が引き出された段と反対側の段において、巻回部１０の外周側が最も外部電極４Ａ、４Ｂとの電位差が大きくなり、内周側にいくにつれて電位差は小さくなっていくので、巻回部１０の外周側の外部電極４Ａ、４Ｂと対向する面に絶縁体部２０を形成することが有効である。よって、素体２の主面２ａ、２ｂ側から透視したとき、巻回部１０の外周から所定の長さＬの範囲まで、巻回部１０の外部電極４Ａ、４Ｂと対向する面に絶縁体部２０を形成することにより、効果的に巻回部１０と外部電極４との間の耐圧を向上させることができる。 In the stage opposite to the stage where the drawer portion of the winding portion 10 is pulled out, the potential difference between the outer peripheral side of the winding portion 10 and the external electrodes 4A and 4B is the largest, and the potential difference becomes smaller toward the inner peripheral side. Therefore, it is effective to form the insulator portion 20 on the surface of the winding portion 10 facing the external electrodes 4A and 4B on the outer peripheral side. Therefore, when viewed from the main surfaces 2a and 2b of the prime field 2, an insulator is provided on the surface of the winding portion 10 facing the external electrodes 4A and 4B from the outer periphery of the winding portion 10 to a predetermined length L. By forming the portion 20, the withstand voltage between the winding portion 10 and the external electrode 4 can be effectively improved.

（実施例）
次に、上記の長さＬ及び厚みＴを様々に異ならせたインダクタ１を試作し、耐圧試験を行った実施例の説明を行う。
下記の表１は、図１～図３に示すインダクタにおいて、素体の高さを１ｍｍ、コイルの巻回部の高さを０．２ｍｍとした場合において、絶縁体部２０の厚みＴを変化させたインダクタ１を試作して、耐圧試験を行った結果を示す。絶縁体部の厚みと耐電圧は１０個のインダクタについて測定し、その平均を求めた。 (Example)
Next, an example in which an inductor 1 having variously different lengths L and thicknesses T is prototyped and a withstand voltage test is performed will be described.
Table 1 below shows that in the inductors shown in FIGS. 1 to 3, the thickness T of the insulator portion 20 changes when the height of the prime field is 1 mm and the height of the coil winding portion is 0.2 mm. The result of the withstand voltage test by making a trial production of the made inductor 1 is shown. The thickness and withstand voltage of the insulator portion were measured for 10 inductors, and the average was calculated.

（表１）

(Table 1)

下記の表２は、図１～図３に示すインダクタにおいて、絶縁体部２０の厚みＴ＝６μｍとした場合に、巻回部１０の外周からの長さＬを変化させたインダクタを試作して、耐圧試験を行った結果を示す。絶縁体部の長さ、絶縁体部の比、耐電圧は１０個のインダクタについて測定し、その平均を求めた。
なお、素体の主面２ａ、２ｂから透視したとき、巻回部１０の外部電極４Ａ、４Ｂと対向する面（太字点線で囲まれた部分）全域における長さＬは２７６μｍである。下表に示す”絶縁体部の比”は、巻回部１０の外部電極４Ａ、４Ｂと対向する面の面積（太字点線で囲まれた部分）に対する各々の長さＬにおける絶縁体部２０の面積の比を示す。 In Table 2 below, in the inductors shown in FIGS. 1 to 3, when the thickness T of the insulator portion 20 is T = 6 μm, an inductor in which the length L from the outer circumference of the winding portion 10 is changed is prototyped. , The result of the withstand voltage test is shown. The length of the insulator part, the ratio of the insulator part, and the withstand voltage were measured for 10 inductors, and the average was calculated.
When viewed through from the main surfaces 2a and 2b of the prime field, the length L in the entire surface (the portion surrounded by the bold dotted line) facing the external electrodes 4A and 4B of the winding portion 10 is 276 μm. The "ratio of the insulator portion" shown in the table below is the "ratio of the insulator portion" of the insulator portion 20 at each length L with respect to the area of the surface of the winding portion 10 facing the external electrodes 4A and 4B (the portion surrounded by the bold dotted line). Shows the area ratio.

（表２）

(Table 2)

表１に示すように、絶縁体部２０の厚みＴが１．９μｍ以上ある場合には、４８Ｖ以上の耐電圧が得られ、厚みＴが４．２μｍ以上ある場合には、１０３Ｖ以上の耐電圧が得られることが明らかになった。また、表２に示すように、巻回部１０の外部電極４との対向面積との比において、２８％以上の領域に絶縁体部２０が形成されていれば、十分な耐電圧が得られることが判明した。 As shown in Table 1, when the thickness T of the insulator portion 20 is 1.9 μm or more, a withstand voltage of 48 V or more can be obtained, and when the thickness T is 4.2 μm or more, a withstand voltage of 103 V or more can be obtained. It became clear that Further, as shown in Table 2, if the insulator portion 20 is formed in a region of 28% or more in the ratio of the winding portion 10 to the facing area with the external electrode 4, a sufficient withstand voltage can be obtained. It has been found.

以上より、絶縁体部２０の厚みＴが２μｍ以上あるのが好ましく、４μｍ以上あるのがより好ましいと言える。絶縁体部２０の巻回部１０の外周からの長さＬは、巻回部１０の外部電極４との対向面積との比が２８％以上となるのが好ましく、５７％以上となるのがより好ましいと言える。 From the above, it can be said that the thickness T of the insulator portion 20 is preferably 2 μm or more, and more preferably 4 μm or more. The length L of the insulator portion 20 from the outer circumference of the winding portion 10 preferably has a ratio of 28% or more, preferably 57% or more, to the area facing the external electrode 4 of the winding portion 10. It can be said that it is more preferable.

（第２の実施形態に係るインダクタ）
次に、図４及び図５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４は、本発明の第２の実施形態に係るインダクタを素体の主面から透視して示した平面図である。図５は、図４の断面Ｂ－Ｂを模式的に示す断面図である。
本実施形態に係る素体２及び外部電極４Ａ、４Ｂは、上記の第１の実施形態とほぼ同様の形状を有する。 (Inductor according to the second embodiment)
Next, the inductor according to the second embodiment of the present invention will be described with reference to FIGS. 4 and 5. FIG. 4 is a plan view showing the inductor according to the second embodiment of the present invention as seen through from the main surface of the prime field. FIG. 5 is a cross-sectional view schematically showing a cross section BB of FIG.
The prime field 2 and the external electrodes 4A and 4B according to the present embodiment have substantially the same shape as that of the first embodiment described above.

上記の第１の実施形態では、巻回部１０の引き出し部１６Ａ、１６Ｂが引き出された段と反対側の段の外部電極４Ａ、４Ｂと対向する面にのみ絶縁体部２０が形成されているが、本実施形態では、巻回部１０の引き出し部１６Ａ、１６Ｂが引き出された段と同じ段の外部電極４Ａ、４Ｂと対向する面にも絶縁体部２０が形成されている点で、第１の実施形態と異なる。つまり、本実施形態では、主面２ａ、２ｂから透視したとき、巻回部１０の外部電極４Ａ、４Ｂと対向する４つの面全てに絶縁体部２０が形成されている。 In the first embodiment described above, the insulator portion 20 is formed only on the surface of the winding portion 10 facing the external electrodes 4A and 4B of the stage opposite to the stage from which the drawer portions 16A and 16B are drawn out. However, in the present embodiment, the insulator portion 20 is formed on the surface of the winding portion 10 facing the external electrodes 4A and 4B of the same stage as the drawer portions 16A and 16B from which the winding portions 10 are drawn. It is different from the embodiment of 1. That is, in the present embodiment, the insulator portion 20 is formed on all four surfaces of the winding portion 10 facing the external electrodes 4A and 4B when viewed through from the main surfaces 2a and 2b.

引き出し部１６Ａ、１６Ｂが引き出された段と同じ巻回部１０の段における外部電極４Ａ、４Ｂとの電位差は、反対の段における外部電極４Ａ、４Ｂとの電位差より小さいが、外部電極４Ａ、４Ｂと対向する全ての箇所に絶縁体部２０を形成することにより、より確実に巻回部１０と外部電極４との間の耐圧を向上させることができる。 The potential difference between the external electrodes 4A and 4B in the same winding unit 10 stage as the stage in which the drawing portions 16A and 16B are drawn out is smaller than the potential difference with the external electrodes 4A and 4B in the opposite stage, but the external electrodes 4A and 4B. By forming the insulator portion 20 at all the locations facing the winding portion 10, the withstand voltage between the winding portion 10 and the external electrode 4 can be improved more reliably.

（第３の実施形態に係るインダクタ）
次に、図６を参照しながら、本発明の第３の実施形態に係るインダクタの説明を行う。図６は、本発明の第３の実施形態に係るインダクタを模式的に示す側面断面図である。図６は、上記の図３、図５と同様な断面を示している。
本実施形態に係る素体２は、上記の第１、第２の実施形態とほぼ同様の形状を有する。しかし、外部電極４Ａ、４Ｂは、実装面となる一方の主面２ｂにのみ形成された、Ｌ字形の断面形状を有する点で上記の第１、第２の実施形態と異なる。 (Inductor according to the third embodiment)
Next, the inductor according to the third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a side sectional view schematically showing an inductor according to a third embodiment of the present invention. FIG. 6 shows a cross section similar to that of FIGS. 3 and 5 described above.
The prime field 2 according to the present embodiment has substantially the same shape as the first and second embodiments described above. However, the external electrodes 4A and 4B differ from the first and second embodiments described above in that they have an L-shaped cross-sectional shape formed only on one main surface 2b which is a mounting surface.

このため、主面２ｂから透視したとき、巻回部１０の外部電極４Ａ、４Ｂと対向する２つの面に絶縁体部２０が形成されている。これにより、外部電極４Ａ、４Ｂの形状に合わせて、合理的に絶縁体部２０を配置して、巻回部１０と外部電極４との間の耐圧を向上させることができる。 Therefore, when viewed through from the main surface 2b, the insulator portion 20 is formed on the two surfaces of the winding portion 10 facing the external electrodes 4A and 4B. Thereby, the insulator portion 20 can be rationally arranged according to the shapes of the external electrodes 4A and 4B, and the withstand voltage between the winding portion 10 and the external electrode 4 can be improved.

（製造方法）
（インダクタの製造方法）
上記のインダクタ１の製造方法を、以下に簡略に説明する。以下では、図１に示すインダクタ１を製造する場合を例にとって説明する。
例示するインダクタ１の製造方法は、
（１）コイル８を形成するコイル形成工程と、
（２）コイル８に絶縁体部２０をする絶縁体部形成工程と、
（３）絶縁体部２０を有するコイル８が磁性部内に埋設された素体２を形成する素体形成工程と、
（４）外部電極４Ａ、４Ｂを形成する外部電極形成工程と、
を含む。 (Production method)
(Inductor manufacturing method)
The manufacturing method of the above-mentioned inductor 1 will be briefly described below. Hereinafter, a case where the inductor 1 shown in FIG. 1 is manufactured will be described as an example.
The method of manufacturing the inductor 1 illustrated is
(1) A coil forming step for forming the coil 8 and
(2) Insulator portion forming step of forming the insulator portion 20 on the coil 8 and
(3) A prime field forming step in which the coil 8 having the insulator portion 20 forms the prime field 2 embedded in the magnetic portion.
(4) External electrode forming steps for forming the external electrodes 4A and 4B, and
including.

（１）コイル形成工程
まず、絶縁被膜を有する導線の断面の長辺を巻線機の巻芯に接触させた状態で、巻芯に沿って上下２段に巻回して、所謂α巻きの巻回部１０を形成し、巻回部１０のそれぞれの段の外周から引き出し部１６Ａ、１６Ｂを引き出し、巻線機の巻芯から巻回部１０を取り外してコイル８を形成する。
（２）絶縁体部形成工程
次に、形成されたコイル８の巻回部１０の所定の箇所の絶縁被膜上に、絶縁材料を所定の厚みＴとなるように塗布をして、巻回部１０の絶縁被膜上に絶縁体部２０を形成する。ただし、絶縁体部２０を形成する方法は、塗布に限られず、既知の任意の方法を採用することができる。また、絶縁体部は、コイル８が巻線機の巻芯に取り付けられた状態で形成することもできる。 (1) Coil forming process First, with the long side of the cross section of the conducting wire having an insulating coating in contact with the winding core of the winding machine, the coil is wound in two upper and lower stages along the winding core, so-called α-winding winding. The winding portion 10 is formed, the drawing portions 16A and 16B are pulled out from the outer periphery of each stage of the winding portion 10, and the winding portion 10 is removed from the winding core of the winding machine to form the coil 8.
(2) Insulator portion forming step Next, an insulating material is applied on the insulating coating at a predetermined portion of the wound portion 10 of the formed coil 8 so as to have a predetermined thickness T, and the wound portion is formed. The insulator portion 20 is formed on the insulating coating of 10. However, the method for forming the insulator portion 20 is not limited to coating, and any known method can be adopted. Further, the insulator portion can also be formed in a state where the coil 8 is attached to the winding core of the winding machine.

（３）素体形成工程
次に、絶縁体部２０を有するコイル８を金型のキャビティに収容し、キャビティ内に、磁性粉と樹脂の混合物を充填する。このとき、引き出し部１６Ａ、１６Ｂの先端１６Ａａ、１６Ｂａを素体２の側面２ｃ、２ｅに露出させる場合は、引き出し部１６Ａ、１６Ｂの先端１６Ａａ、１６Ｂａの表面をキャビティの側面に接触させる。この状態で、金型内で磁性粉と樹脂の混合物を樹脂の軟化温度以上の温度(例えば、６０℃以上１５０℃以下)に加温した状態で、１００ｋｇ／ｃｍ^２以上５００ｋｇ／ｃｍ^２以下程度で加圧し、樹脂の硬化温度以上の温度(例えば、１００℃以上２２０℃以下)に加温して成形・硬化する。これにより、磁性部６とコイル８とが一体化されて、側面２ｃ、２ｅに引き出し部１６Ａ、１６Ｂの先端１６Ａａ、１６Ｂａの少なくとも一部が露出した素体２が形成される。なお、硬化は、成形後に行っても良い。 (3) Element Forming Step Next, the coil 8 having the insulator portion 20 is housed in the cavity of the mold, and the cavity is filled with a mixture of magnetic powder and resin. At this time, when the tips 16Aa and 16Ba of the drawers 16A and 16B are exposed to the side surfaces 2c and 2e of the prime field 2, the surfaces of the tips 16Aa and 16Ba of the drawers 16A and 16B are brought into contact with the side surfaces of the cavity. In this state, the mixture of magnetic powder and resin is heated to a temperature equal to or higher than the softening temperature of the resin (for example, 60 ° C or higher and 150 ° C or lower) in the mold, and is about 100 kg / cm ² or higher and 500 kg / cm ² or lower. Pressurize with and heat to a temperature equal to or higher than the curing temperature of the resin (for example, 100 ° C. or higher and 220 ° C. or lower) to form and cure the resin. As a result, the magnetic portion 6 and the coil 8 are integrated, and a prime field 2 in which at least a part of the tips 16Aa and 16Ba of the drawer portions 16A and 16B is exposed is formed on the side surfaces 2c and 2e. The curing may be performed after molding.

（４）外部電極形成工程
次に、引き出し部１６Ａ、１６Ｂの先端１６Ａａ、１６Ｂａが露出する素体２の側面２ｃ、２ｅと、それらの側面２ｃ、２ｅに隣接する４つの面２ａ、２ｂ、２ｄ、２ｆの一部に跨って、互いに離隔した一対の外部電極４Ａ、４Ｂを形成する。一対の外部電極４Ａ、４Ｂは、素体２の所望の位置に導電性ペーストのような流動性を有する導電性樹脂をディップにより塗布することにより形成することができる。また、一対の外部電極４Ａ、４Ｂは、塗布された導電性樹脂上にめっきを施して形成してもよい。めっきは、導電性樹脂上に形成されるニッケル層とニッケル層上に形成されるスズ層により構成される。
以上により、上記の実施形態に係るインダクタ１を製造することができる。 (4) External electrode forming step Next, the side surfaces 2c and 2e of the prime field 2 to which the tips 16Aa and 16Ba of the drawer portions 16A and 16B are exposed, and the four surfaces 2a, 2b and 2d adjacent to the side surfaces 2c and 2e thereof. A pair of external electrodes 4A and 4B separated from each other are formed so as to straddle a part of 2f. The pair of external electrodes 4A and 4B can be formed by applying a conductive resin having fluidity such as a conductive paste to a desired position of the prime field 2 by dipping. Further, the pair of external electrodes 4A and 4B may be formed by plating the coated conductive resin. Plating is composed of a nickel layer formed on a conductive resin and a tin layer formed on the nickel layer.
As described above, the inductor 1 according to the above embodiment can be manufactured.

上記では、本発明の実施形態を説明したが、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、外部電極は、素体の外部電極が形成される面に露出した磁性粉上にメッキを施し、磁性粉に接触する銅層と、銅層上に形成されたニッケル層とニッケル層上に形成されるスズ層により構成されても良い。
また、絶縁体部は、素体の主面側から透視したとき、巻回部の外部電極と対向する面内のみにおいて、巻回部の外周に沿って所定の幅を有する領域に形成されていてもよい。
さらに、絶縁体部は、素体の主面側から透視したとき、巻回部の外部電極と対向する面内のみにおいて、その全面に形成されても良い。
またさらに、絶縁体部は、巻回部の側面に跨って形成されても良い。
また、絶縁体部は、図３、図４、図６において、一方の引き出し端側の巻回部の外部電極と対向する面内にのみ形成されていても良い。 Although the embodiments 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 deviate from the requested scope and ideas of the present invention. It can be realized without any problems. For example, the external electrode is formed on a copper layer that comes into contact with the magnetic powder by plating the exposed magnetic powder on the surface on which the external electrode of the element body is formed, and on the nickel layer and the nickel layer formed on the copper layer. It may be composed of a tin layer formed.
Further, the insulator portion is formed in a region having a predetermined width along the outer periphery of the winding portion only in the plane facing the external electrode of the winding portion when viewed from the main surface side of the prime field. You may.
Further, the insulator portion may be formed on the entire surface only in the plane facing the external electrode of the winding portion when viewed from the main surface side of the prime field.
Furthermore, the insulator portion may be formed so as to straddle the side surface of the winding portion.
Further, in FIG. 3, FIG. 4, and FIG. 6, the insulator portion may be formed only in the plane facing the external electrode of the winding portion on one of the drawer end sides.

１インダクタ
２素体
２ａ、２ｂ、２ｃ、２ｄ、２ｅ、２ｆ面
４Ａ、４Ｂ外部電極
６磁性部
８コイル
１０巻回部
１２上段
１４下段
１６Ａ、１６Ｂ引き出し部
１６Ａａ、１６Ｂａ先端
２０絶縁体部 1 Inductor 2 Prime field 2a, 2b, 2c, 2d, 2e, 2f Surface 4A, 4B External electrode 6 Magnetic part 8 Coil 10 Winding part 12 Upper part 14 Lower part 16A, 16B Drawer part 16Aa, 16Ba Tip 20 Insulator part

Claims

A prime field having a magnetic portion containing magnetic powder and a coil having at least a part embedded in the magnetic portion, and having two main surfaces and side surfaces adjacent to the two main surfaces.
A pair of external electrodes formed on at least one of the main surfaces of the prime field,
Equipped with
The coil is
A winding portion formed by winding a conducting wire having an insulating coating in two upper and lower stages so that both ends are located on the outermost circumference.
A pair of drawers drawn from the outermost circumferences of the upper and lower stages and connected to the external electrodes.
Have,
An inductor characterized in that an insulator portion is formed on an insulating coating on a surface of the winding portion facing the external electrode when viewed from the main surface of the prime field.

It is determined that the insulator portion is formed on the insulating coating of the winding portion only in the surface of the winding portion facing the external electrode on the stage opposite to the stage where the drawing portion is pulled out. The inductor according to claim 1.