JP3654251B2

JP3654251B2 - Coil parts

Info

Publication number: JP3654251B2
Application number: JP2002012515A
Authority: JP
Inventors: 俊之中田; 洋行濱本; 恒次今西; 英敏樋渡; 智一北川
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2002-01-22
Filing date: 2002-01-22
Publication date: 2005-06-02
Anticipated expiration: 2022-01-22
Also published as: JP2003217936A

Description

【０００１】
【発明の属する技術分野】
本発明は、各種民生機器等に用いるコイル部品に関するものである。
【０００２】
【従来の技術】
以下、従来のコイル部品について図面を参照しながら説明する。
【０００３】
図９は従来のコイル部品の斜視図、図１０は同断面図、図１１は同製造工程の一部を示す断面図である。
【０００４】
図９〜図１１に示すように、従来のコイル部品は、貫通孔５１を有するコイル部５２と、このコイル部５２を内包した磁性体からなる外装部５３と、コイル部５２に接続するとともに、外装部５３から突出した端子５４とを備え、外装部５３は、コイル部５２を被覆するように磁性粉末５５を加圧成形して成形した構成である。
【０００５】
外装部５３には、全体に渡って一定の成形圧力が加わっており、外装部５３の密度も全体に渡って略等しいものであった。なお、５９は金型である。
【０００６】
【発明が解決しようとする課題】
上記従来の構成では、低背化を図ろうとすると、外装部５３に加圧する成形圧力を高め、外装部５３を全体に渡って凝縮させる必要がある。
【０００７】
しかし、外装部５３の凝縮に応じて低背化はされるものの、外装部５３の上面部や下面部が薄くなり、コイル部５２の貫通孔内を通過する磁束が外装部５３の上面部や下面部を通過する際、磁気飽和を生じ易くなって信頼性が劣化するという問題点を有していた。
【０００８】
本発明は上記問題点を解決するために、低背化を図るために上面部や下面部を薄くしても、磁気飽和が生じにくい、信頼性を向上したコイル部品を提供することを目的としている。
【０００９】
【課題を解決するための手段】
上記目的を達成するために本発明は、以下の構成を有する。
【００１０】
本発明の請求項１記載の発明は、特に、外装部は、熱硬化性樹脂を含有した結合剤と磁性粉末とが混合され加圧成形された圧粉磁芯であって、コイル部が内包される前記外装部の内包厚寸法が前記コイル部の貫通孔の直径よりも小さいとともに、前記外装部の上面部および下面部の密度が前記外装部の中間部の密度よりも大きい構成である。
【００１１】
上記構成により、コイル部を内包する内包厚寸法（コイル部と外装部の表面との距離）をコイル部の貫通孔の直径よりも小さくなるまで、コイル部の上方部分に対応する外装部の上面部とコイル部の下方部分に対応する外装部の下面部とを薄く形成して全体として低背化を図っても、上面部の密度および下面部の密度を中間部の密度よりも大きくしているので、上面部および下面部において磁気飽和の発生を抑制することができる。
【００１２】
すなわち、コイル部の貫通孔の内部は、外装部の中間部に相当するが、この中間部の密度よりも外装部の上面部および下面部の密度の方が大きいので、貫通孔の内部を通過する磁束が、貫通孔の直径よりも小さい上面部および下面部を通過しても、上面部および下面部では中間部よりも密度が大きい分だけ透磁率を大きくすることができ、上面部および下面部において磁気飽和を発生させずに、低背化を図ることができるものである。
【００１３】
本発明の請求項２記載の発明は、特に、外装部の中間部は、前記コイル部の外周面の外側部分に対応する外側中間部の密度が、前記コイル部の貫通孔内に対応する内側中間部の密度よりも大きい構成である。
【００１４】
上記構成により、外側中間部は内側中間部よりも密度が大きい分だけ透磁率を大きくすることができ、外側中間部において磁気飽和を発生させずに横方向の寸法を低減し、実装時における省スペース化を図ることができる。
【００１５】
本発明の請求項３記載の発明は、特に、外装部は、上面部および下面部の密度が５．０〜６．０ｇ／ｃｍ ³ であるとともに、中間部の密度が上面部および下面部の密度の８５％〜９８％である構成である。
【００１６】
上記構成により、コイル部への応力を必要以上に与えず、コイル部の破壊を抑制しつつ、内部応力等に起因した外装部自体の破壊を抑制できる。また、磁気飽和の発生も抑制し、小型化を図ることができる。
【００１７】
本発明の請求項４記載の発明は、特に、コイル部は、平角線を巻回したエッジワイズ巻線とし、隣接する前記平角線が密着した構成である。
【００１８】
上記構成により、コイル部は、エッジワイズ巻線としているので、占積率を向上するとともに、大電流に対応させることができる。特に、隣接する平角線が密着しているので、平角線間に外装部が形成されておらず、平角線を周回する磁束の発生を抑制して、損失を低減できる。
【００１９】
本発明の請求項５記載の発明は、特に、熱硬化性樹脂は、高硬度樹脂成分と弾性樹脂成分とを有するシリコン樹脂とした構成である。
【００２０】
熱硬化性樹脂として、高硬度樹脂成分と弾性樹脂成分とを有するシリコン樹脂を用いているので、硬度と脆さのバランスの取れた強度を有する外装部を形成でき、外装部の不良を減少させることができる。
【００２１】
【発明の実施の形態】
以下、本発明の一実施の形態におけるコイル部品について図面を参照しながら説明する。
【００２２】
図１は本発明の一実施の形態におけるコイル部品の断面図、図２は同斜視図、図３は同製造工程の一部を示す図、図４は同要部である圧粉体の斜視図、図５は同要部である端子を接続したコイル部の斜視図、図６は同要部である端子形成前の斜視図である。
【００２３】
図１〜図６に示すように、本発明の一実施の形態におけるコイル部品は、高さ２〜５ｍｍで１０ｍｍ角形状の大きさであって、貫通孔１を有したコイル部２と、このコイル部２を内包した外装部３と、コイル部２に接続するとともに、外装部３から突出した端子４とを備えている。
【００２４】
また、外装部３は、磁性粉末を含有した圧粉磁芯（ダストコア）であって、高硬度樹脂成分と弾性樹脂成分とを有するシリコン樹脂である熱硬化性樹脂を含有した結合剤と磁性粉末とを熱硬化性樹脂が完全硬化しない非加熱状態で混合するとともに０．５〜２．０ｔ／ｃｍ²で加圧成形した圧粉体５を、コイル部２を被覆するように３．０〜５．０ｔ／ｃｍ²で再加圧成形するとともに熱硬化性樹脂が完全硬化するように１００〜１８０℃で加熱して形成している。
【００２５】
この圧粉磁芯（ダストコア）は、磁性粉末として、熱処理を施した軟磁性合金粉末を用い、この平均粒径を１μｍ〜１００μｍとし、この組成を、１ｗｔ％≦成分Ａ≦７ｗｔ％（成分Ａは、シリコン（Ｓｉ）、アルミニウム（Ａｌ）、チタン（Ｔｉ）、マグネシウム（Ｍｇ）の内、少なくとも１つを含む）、２ｗｔ％≦クロム（Ｃｒ）≦８ｗｔ％、０．０５ｗｔ％≦酸素（Ｏ）≦０．６ｗｔ％、０．０１ｗｔ％≦マンガン（Ｍｎ）≦０．２ｗｔ％、０．００５ｗｔ％≦カーボン（Ｃ）≦０．２ｗｔ％、そして残部を鉄（Ｆｅ）としている（成分Ａの替わりに、２ｗｔ％≦ニッケル（Ｎｉ）≦１５ｗｔ％としてもよい）。
【００２６】
さらに、圧粉体５は２個用いており、この圧粉体５には再加圧成形する際に圧粉体５の形状がくずれない硬度の強硬度部と再加圧成形する際に圧粉体５の形状がくずれる硬度の弱硬度部とを設け、圧粉体５の形状を背面部６に中脚部７と外脚部８とを有した断面Ｅ字形状のポット型にし、背面部６を強硬度部にするとともに、中脚部７と外脚部８を弱硬度部にしている。この弱硬度部および強硬度部は、圧粉体の密度を小さくした部分（弱硬度部）と密度を大きくした部分（強硬度部）とにより形成している。弱硬度部は数ｋｇ／ｃｍ²の加圧により形状がくずれる硬度にしている。
【００２７】
ここで、圧粉体５の形状がくずれる硬度とは、磁性粉末の粒子サイズでくずれることであり、圧粉体５の形状がくずれない硬度の強硬度部において、ブロック的（団塊になって）にくずれた状態は、磁性粉末の粒子サイズでくずれてないので、くずれる硬度の範囲には含まないものとしている。
【００２８】
そして、外装部３は一方の圧粉体５および他方の圧粉体５の両方の圧粉体５の強硬度部がコイル部２の一面（上下面）を互いに支持するとともに、弱硬度部がコイル部２の他面（外周面および貫通孔１の内壁面）を被覆するように圧粉体を再加圧成形し、かつ熱硬化性樹脂が完全硬化するように加熱したものである。
【００２９】
このとき、外装部３は、コイル部２を内包する内包厚寸法（Ｗ）をコイル部２の貫通孔１の直径よりも小さくし、コイル部２の上方部分に対応する外装部３の上面部１１と、コイル部２の下方部分に対応する外装部３の下面部１２と、コイル部２の高さ部分に対応する外装部３の中間部１３とにおいて、上面部１１の密度および下面部１２の密度を中間部１３の密度よりも大きくしている。
【００３０】
特に、中間部１３は、コイル部２の貫通孔１内に対応する内側中間部１５と、コイル部２の外周面の外側部分に対応する外側中間部１４とにおいて、外側中間部１４の密度を内側中間部１５の密度よりも大きくしている。
【００３１】
これらの密度については、上面部１１の密度および下面部１２の密度を５．０〜６．０ｇ／ｃｍ³とし、中間部１３の密度をその８５％〜９８％の密度としている。
【００３２】
上記コイル部品の製造方法では、コイル部２を磁性体からなる外装部３で内包する外装部形成工程と、コイル部２に接続するとともに、外装部３から突出した端子４とを形成する端子形成工程とを設けている。
【００３３】
外装部形成工程では、まず、高硬度樹脂成分と弾性樹脂成分とを有するシリコン樹脂である熱硬化性樹脂を含有した結合剤と磁性粉末とを熱硬化性樹脂が完全硬化しないように非加熱状態で混合するとともに加圧成形して２個の圧粉体５を成形する工程を設けている。
【００３４】
このとき、圧粉体５は、その形状を背面部６に中脚部７と外脚部８とを有した断面Ｅ字形状のポット型にし、さらに、背面部６は再加圧成形する際に圧粉体５の形状がくずれない硬度の強硬度部にするとともに、中脚部および外脚部は再加圧成形する際に圧粉体の形状がくずれる硬度の弱硬度部にしている。
【００３５】
次に、２個の圧粉体５の強硬度部がコイル部２の一面（上下面）を互いに支持するとともに、弱硬度部がコイル部２の他面（外周面および貫通孔１の内壁面）を被覆するように圧粉体５を再加圧成形し、かつ熱硬化性樹脂が完全硬化するように加熱成形して外装部３を成形する工程を設けている。
【００３６】
このとき、２個の圧粉体５の背面部６がコイル部２を支持しつつ、２つの金型９が圧粉体５の弱硬度部の中間部７と外脚部８を押圧して、圧粉体５の弱硬度部をくずしつつコイル部２の他面（外周面および貫通孔１の内壁面）を被覆させて加圧している。
【００３７】
特に、この場合では、コイル部２の他面（貫通孔１の内壁面）に対向した圧粉体５の背面部６（強硬度部）が、コイル部２の貫通孔１の中にブロック的に埋没するとともに、端子４に対向した圧粉体５の背面部６（強硬度部）が、端子４に向かってブロック的に埋没しつつ、圧粉体５の中脚部７（弱硬度部）および外脚部８（弱硬度部）がくずれて、コイル部２の他面（外周面および貫通孔１の内壁面）を被覆している。
【００３８】
また、この外装部形成工程では、コイル部２を内包する内包厚寸法（Ｗ）をコイル部２の貫通孔１の直径よりも小さくするとともに、コイル部２の上方部分に対応する外装部３の上面部１１の密度およびコイル部２の下方部分に対応する外装部３の下面部１２の密度をコイル部２の高さ部分に対応する外装部の中間部１３の密度よりも大きくする工程を設けている。
【００３９】
さらに、中間部１３には、コイル部２の貫通孔１内に対応する内側中間部１５と、コイル部２の外周面の外側部分に対応する外側中間部１４とを設け、外側中間部１４の密度を内側中間部１５の密度よりも大きくする工程も設けている。
【００４０】
そして、外装部３は、上面部１１の密度および下面部１２の密度を５．０〜６．０ｇ／ｃｍ³とし、中間部１３の密度をその８５％〜９８％の密度となるようにしている。
【００４１】
上記構成および方法により、コイル部２を内包する内包厚寸法（Ｗ）（コイル部２と外装部３の表面との距離）をコイル部２の貫通孔１の直径よりも小さくなるまで、コイル部２の上方部分に対応する外装部３の上面部１１とコイル部２の下方部分に対応する外装部３の下面部１２とを薄く形成して全体として低背化を図っても、上面部１１の密度および下面部１２の密度を中間部１３の密度よりも大きくしているので、上面部１１および下面部１２において磁気飽和の発生を抑制することができる。
【００４２】
すなわち、コイル部２の貫通孔１の内部は、外装部３の中間部１３に相当するが、この中間部１３の密度よりも外装部３の上面部１１および下面部１２の密度の方が大きいので、貫通孔１の内部を通過する磁束が、貫通孔１の直径よりも小さい上面部１１および下面部１２を通過しても、上面部１１および下面部１２では中間部１３よりも密度が大きい分だけ透磁率を大きくすることができ、上面部１１および下面部１２において磁気飽和を発生させずに、低背化を図ることができるものである。
【００４３】
このとき、中間部１３は、コイル部２の貫通孔１に対応する内側中間部１５と、コイル部２の外周面の外側部分に対応する外側中間部１４とを有し、外側中間部１４の密度を内側中間部１５の密度よりも大きくしているので、外側中間部１４は内側中間部１５よりも密度が大きい分だけ透磁率を大きくすることができ、外側中間部１４において磁気飽和を発生させずに横方向の寸法を低減し、実装時における省スペース化を図ることができる。
【００４４】
特に、外装部３は、上面部１１の密度および下面部１２の密度を５．０〜６．０ｇ／ｃｍ³とし、中間部１３の密度をその密度の８５％〜９８％の密度としているので、コイル部２への応力を必要以上に与えず、コイル部２の破壊を抑制しつつ、内部応力等に起因した外装部３自体の破壊を抑制できる。また、磁気飽和の発生も抑制し、小型化を図ることができる。
【００４５】
この外装部３は、圧粉磁芯であって、その材質を特有の組成にしているので、直流重畳特性に有利であり（鉄（Ｆｅ）成分の割合が多いため）、しかも、鉄（Ｆｅ）成分の含有による錆びの発生を抑制し（クロム（Ｃｒ）成分の含有により）、１００ｋＨｚ以上の高周波領域での損失を抑制でき（クロム（ｃｒ）≦８ｗｔ％のため）、磁気特性を損ねることなく、かつ耐腐食性に優れた複合磁性材料を実現できる。
【００４６】
また、一般的に加圧成形には通常金型を用いて成形するが、圧粉体５が固形物となるので、金型９とコイル部２との間で圧粉体５の量が再加圧成形時に変動しにくく、外装部３の被覆厚さがコイル部２の周囲全体に渡って均一になりやすく、インダクタンス値およびインダクタンス値の直流重畳時の飽和特性および磁気損失等の特性バラツキを抑制できるとともに、圧粉体５自体によってコイル部２を支持できるのでコイル部２の位置決めが的確になり外装部３の不良成形を防止できる。このとき、圧粉体５には、磁性粉末と熱硬化性樹脂を含有した結合剤とを混合加圧するが、熱硬化性樹脂として、高硬度樹脂成分と弾性樹脂成分とを有するシリコン樹脂を用いているので、硬度と脆さのバランスの取れた強度を有する外装部を形成でき、外装部の不良を減少させることができる。
【００４７】
さらに、圧粉体５は再加圧成形してコイル部２を被覆するので、コイル部２を的確に被覆することができ、圧粉体５とコイル部２との間を隙間なく充填することもでき、磁気ギャップを減少させて磁気効率を向上することができる。
【００４８】
特に、圧粉体５の強硬度部はコイル部２の一面を強固に支持するので、再加圧成形時にコイル部２の位置ずれが生じにくく、圧粉体５の弱硬度部がその形をくずしながらコイル部２の他面を容易に被覆することができ、外装部３の被覆厚さをコイル部２の周囲全体に渡って均一にさせやすく、特性バラツキを抑制できる。
【００４９】
そして、圧粉体５の形状は背面部６に中脚部７と外脚部８とを有したＥ字形状にし、背面部６を強硬度部にするとともに、中脚部７および外脚部８を弱硬度部にしているので、より一層、圧粉体５の強硬度部に対して位置ずれが生じにくく、コイル部２の他面を容易に被覆することができ、特性バラツキを抑制できる。
【００５０】
このように本発明の実施の形態によれば、外装部３の被覆厚さがコイル部２の周囲全体に渡って均一になりやすく、特性バラツキを抑制できるだけでなく、外装部３の上面部１１および下面部１２では中間部１３よりも密度が大きい分だけ透磁率を大きくすることができ、上面部１１および下面部１２において磁気飽和を発生させずに、低背化を図ることができるものである。
【００５１】
なお、本発明の実施の形態では、圧粉体５の形状をＥ字形状にしたが、本発明の趣旨を逸脱しない範囲において、中脚部７の長さを外脚部８の長さよりも長くしたり、短くしたり、それ以外の形状でもよい。特に、背面部６に中脚部７のみを形成したＴ字形状や外脚部８のみを形成したコ字形状は略Ｅ字形状とみなしている。
【００５２】
また、コイル部２と圧粉体５との位置関係も、２個の圧粉体５の強硬度部がコイル部２の一面を支持しなくても、少なくとも一方の圧粉体５の強硬度部がコイル部２の一面を支持するようになっていればよい。このとき、Ｅ字形状の圧粉体５の強硬度部の密度を弱硬度部の密度よりも大きくしてもよい。
【００５３】
さらに、コイル部２は、丸線の他に、平角線を巻回したエッジワイズ巻線としてもよく、この場合、占積率を向上するとともに、大電流に対応させることができ、特に、隣接する平角線間に外装部３を非形成するように、隣接する平角線を密着すれば、平角線間に外装部３が形成されず、平角線を周回する磁束の発生を抑制して、損失を低減できる。
【００５４】
他の例としては、図７、図８に示すように、一方の圧粉体５は強硬度部の背面部６がコイル部２の一面を支持するようにし、他方の圧粉体５はコイル部２の貫通孔１に中脚部７を挿入するようにして、再加圧成形したり、２つの圧粉体５の中脚部７および外脚部８の先端に微小凹凸部１０を設けるとともに、２つの圧粉体５の中脚部７および外脚部８が互いに対向するようにして、再加圧成形したり、圧粉体５の背面部６に分割用の分割溝を設けて、再加圧成形したりしてもよく、ともに、より一層、コイル部２の他面を容易に被覆することができ、特性バラツキを抑制できる。
【００５５】
この際、本発明の実施の形態では、再加圧成形前、または再加圧成形中において、圧粉体５の強硬度部がコイル部２の一面を支持しているが、再加圧成形後においても、圧粉体の強硬度部がコイル部２の一面を支持するようにすることが望ましい。
【００５６】
【発明の効果】
以上のように本発明は、コイル部を内包する内包厚寸法（コイル部と外装部の表面との距離）をコイル部の貫通孔の直径よりも小さくなるまで、コイル部の上方部分に対応する外装部の上面部とコイル部の下方部分に対応する外装部の下面部とを薄く形成して全体として低背化を図っても、上面部の密度および下面部の密度を中間部の密度よりも大きくしているので、上面部および下面部において磁気飽和の発生を抑制することができる。
【００５７】
すなわち、コイル部の貫通孔の内部は、外装部の中間部に相当するが、この中間部の密度よりも外装部の上面部および下面部の密度の方が大きいので、貫通孔の内部を通過する磁束が、貫通孔の直径よりも小さい上面部および下面部を通過しても、上面部および下面部では中間部よりも密度が大きい分だけ透磁率を大きくすることができ、上面部および下面部において磁気飽和を発生させずに、低背化を図ったコイル部品を提供することができるものである。
【図面の簡単な説明】
【図１】本発明の一実施の形態におけるコイル部品の断面図
【図２】同斜視図
【図３】同製造工程の一部を示す図
【図４】同要部である圧粉体の斜視図
【図５】同要部である端子を接続したコイル部の斜視図
【図６】同要部である端子形成前の斜視図
【図７】本発明の一実施の形態における他の製造工程の一部を示す図
【図８】本発明の一実施の形態におけるさらに他のコイル部品の製造工程の一部を示す図
【図９】従来のコイル部品の斜視図
【図１０】同断面図
【図１１】同製造工程の一部を示す断面図
【符号の説明】
１貫通孔
２コイル部
３外装部
４端子
５圧粉体
６背面部
７中脚部
８外脚部
９金型
１０微小凹凸部
１１上面部
１２下面部
１３中間部
１４外側中間部
１５内側中間部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a coil component used for various consumer devices.
[0002]
[Prior art]
Hereinafter, conventional coil components will be described with reference to the drawings.
[0003]
9 is a perspective view of a conventional coil component, FIG. 10 is a sectional view thereof, and FIG. 11 is a sectional view showing a part of the manufacturing process.
[0004]
As shown in FIGS. 9 to 11, the conventional coil component is connected to the coil part 52 having the through hole 51, the exterior part 53 made of a magnetic material including the coil part 52, and the coil part 52. And a terminal 54 protruding from the exterior portion 53, and the exterior portion 53 is configured by press-molding the magnetic powder 55 so as to cover the coil portion 52.
[0005]
A constant molding pressure was applied to the entire exterior portion 53, and the density of the exterior portion 53 was substantially equal throughout. Reference numeral 59 denotes a mold.
[0006]
[Problems to be solved by the invention]
In the conventional configuration, in order to reduce the height, it is necessary to increase the molding pressure applied to the exterior portion 53 and condense the exterior portion 53 throughout.
[0007]
However, although the height is reduced according to the condensation of the exterior portion 53, the upper surface portion and the lower surface portion of the exterior portion 53 are thinned, and the magnetic flux passing through the through hole of the coil portion 52 is When passing through the lower surface, there is a problem that magnetic saturation is likely to occur and reliability is deteriorated.
[0008]
SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a coil component with improved reliability, which is less likely to cause magnetic saturation even if the upper surface portion and the lower surface portion are thinned to reduce the height. Yes.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration.
[0010]
In the invention of claim 1 of the present invention, in particular, the exterior part is a powder magnetic core formed by pressure-molding a binder containing a thermosetting resin and a magnetic powder, and the coil part is included. The inner thickness of the exterior part is smaller than the diameter of the through hole of the coil part, and the density of the upper surface part and the lower surface part of the exterior part is larger than the density of the intermediate part of the exterior part .
[0011]
With the above configuration, the upper surface of the exterior part corresponding to the upper part of the coil part until the inner thickness dimension (distance between the coil part and the surface of the exterior part) enclosing the coil part becomes smaller than the diameter of the through hole of the coil part. Even if the lower part of the exterior part corresponding to the lower part of the coil part and the coil part is formed thin and the overall height is reduced, the density of the upper part and the density of the lower part are made larger than the density of the intermediate part. Therefore, the occurrence of magnetic saturation can be suppressed at the upper surface portion and the lower surface portion.
[0012]
That is, the inside of the through-hole of the coil portion corresponds to the intermediate portion of the exterior portion, but the density of the upper surface portion and the lower surface portion of the exterior portion is larger than the density of this intermediate portion, so it passes through the inside of the through-hole. Even if the magnetic flux passing through the upper surface portion and the lower surface portion, which is smaller than the diameter of the through-hole, the magnetic permeability can be increased by the amount higher in density in the upper surface portion and the lower surface portion than in the intermediate portion. The height can be reduced without causing magnetic saturation in the portion.
[0013]
In the invention according to claim 2 of the present invention, in particular, in the intermediate portion of the exterior portion, the density of the outer intermediate portion corresponding to the outer portion of the outer peripheral surface of the coil portion corresponds to the inner portion corresponding to the inside of the through hole of the coil portion. The configuration is larger than the density of the intermediate portion .
[0014]
With the above configuration, the outer intermediate portion can be increased in magnetic permeability by a larger density than the inner intermediate portion, the lateral dimension can be reduced without causing magnetic saturation in the outer intermediate portion, and mounting can be saved. Space can be achieved.
[0015]
In the invention according to claim 3 of the present invention, in particular, in the exterior part, the density of the upper surface part and the lower surface part is 5.0 to 6.0 g / cm ³ , and the density of the intermediate part is that of the upper surface part and the lower surface part. The configuration is 85% to 98% of the density .
[0016]
With the above-described configuration, it is possible to suppress the destruction of the exterior part due to internal stress or the like while suppressing the destruction of the coil part without applying stress to the coil part more than necessary. Moreover, generation | occurrence | production of magnetic saturation can also be suppressed and size reduction can be achieved.
[0017]
In the invention according to claim 4 of the present invention, in particular, the coil portion has an edgewise winding around which a rectangular wire is wound, and the adjacent rectangular wires are in close contact with each other.
[0018]
With the above configuration, since the coil portion is an edgewise winding, the space factor can be improved and a large current can be handled. In particular, since adjacent rectangular wires are in close contact with each other, no exterior portion is formed between the rectangular wires, and the generation of magnetic flux that circulates around the rectangular wires can be suppressed to reduce loss.
[0019]
The invention according to claim 5 of the present invention is particularly configured such that the thermosetting resin is a silicon resin having a high-hardness resin component and an elastic resin component.
[0020]
Since a silicon resin having a high hardness resin component and an elastic resin component is used as the thermosetting resin, it is possible to form an exterior portion having a balance of hardness and brittleness, thereby reducing defects in the exterior portion. be able to.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a coil component according to an embodiment of the present invention will be described with reference to the drawings.
[0022]
1 is a cross-sectional view of a coil component according to an embodiment of the present invention, FIG. 2 is a perspective view thereof, FIG. 3 is a diagram showing a part of the manufacturing process, and FIG. 4 is a perspective view of a green compact as the main part. FIG. 5 and FIG. 5 are perspective views of a coil part to which a terminal which is the main part is connected, and FIG. 6 is a perspective view before the terminal which is the main part is formed.
[0023]
As shown in FIGS. 1 to 6, the coil component in one embodiment of the present invention has a height of 2 to 5 mm, a size of 10 mm square shape, a coil portion 2 having a through hole 1, and this An exterior part 3 including the coil part 2 and a terminal 4 which is connected to the coil part 2 and protrudes from the exterior part 3 are provided.
[0024]
The exterior portion 3 is a dust core containing magnetic powder, and a binder and magnetic powder containing a thermosetting resin which is a silicon resin having a high-hardness resin component and an elastic resin component. Are mixed in a non-heated state in which the thermosetting resin is not completely cured, and the green compact 5 formed by pressure molding at 0.5 to 2.0 t / cm ² is 3.0 to so as to cover the coil portion 2. It is formed by re-press molding at 5.0 t / cm ² and heating at 100 to 180 ° C. so that the thermosetting resin is completely cured.
[0025]
This powder magnetic core (dust core) uses a heat-treated soft magnetic alloy powder as the magnetic powder, the average particle diameter is 1 μm to 100 μm, and the composition is 1 wt% ≦ component A ≦ 7 wt% (component A) Includes at least one of silicon (Si), aluminum (Al), titanium (Ti), and magnesium (Mg)), 2 wt% ≦ chromium (Cr) ≦ 8 wt%, 0.05 wt% ≦ oxygen (O ) ≦ 0.6 wt%, 0.01 wt% ≦ manganese (Mn) ≦ 0.2 wt%, 0.005 wt% ≦ carbon (C) ≦ 0.2 wt%, and the balance is iron (Fe) (component A Instead, 2 wt% ≦ nickel (Ni) ≦ 15 wt%).
[0026]
In addition, two green compacts 5 are used. The green compact 5 has a hard portion having a hardness that does not break the shape of the green compact 5 during re-pressure molding and a green compact 5 during re-press molding. The powder 5 is provided with a weak hardness part that is deformed, and the green compact 5 is formed into a pot shape having an E-shaped cross section having a middle leg part 7 and an outer leg part 8 on the back part 6. While the part 6 is a strong hardness part, the middle leg part 7 and the outer leg part 8 are weak hardness parts. The weak hardness portion and the strong hardness portion are formed of a portion where the density of the green compact is reduced (weak hardness portion) and a portion where the density is increased (strong hardness portion). The weak hardness part is set to a hardness at which the shape is broken by pressurization of several kg / cm ² .
[0027]
Here, the hardness at which the shape of the green compact 5 breaks down means that it breaks down with the particle size of the magnetic powder. Since the broken state is not broken by the particle size of the magnetic powder, it is not included in the range of broken hardness.
[0028]
And the exterior part 3 supports the one surface (upper and lower surfaces) of the coil part 2 mutually while the strong hardness part of the green compact 5 of one green compact 5 and the other green compact 5 mutually has a weak hardness part. The green compact is re-press-molded so as to cover the other surface of the coil portion 2 (the outer peripheral surface and the inner wall surface of the through hole 1), and heated so that the thermosetting resin is completely cured.
[0029]
At this time, the exterior portion 3 has an inner thickness dimension (W) that encloses the coil portion 2 smaller than the diameter of the through hole 1 of the coil portion 2, and an upper surface portion of the exterior portion 3 that corresponds to the upper portion of the coil portion 2. 11, the density of the upper surface portion 11 and the lower surface portion 12 of the lower surface portion 12 of the exterior portion 3 corresponding to the lower portion of the coil portion 2 and the intermediate portion 13 of the exterior portion 3 corresponding to the height portion of the coil portion 2. Is made larger than the density of the intermediate portion 13.
[0030]
In particular, the intermediate portion 13 has the density of the outer intermediate portion 14 in the inner intermediate portion 15 corresponding to the inside of the through hole 1 of the coil portion 2 and the outer intermediate portion 14 corresponding to the outer portion of the outer peripheral surface of the coil portion 2. It is larger than the density of the inner intermediate portion 15.
[0031]
As for these densities, the density of the upper surface portion 11 and the density of the lower surface portion 12 are 5.0 to 6.0 g / cm ^3, and the density of the intermediate portion 13 is 85% to 98%.
[0032]
In the manufacturing method of the coil component, the exterior part forming step for enclosing the coil part 2 with the exterior part 3 made of a magnetic material, and the terminal formation for forming the terminal 4 protruding from the exterior part 3 while being connected to the coil part 2 Process.
[0033]
In the exterior part forming step, first, a binder containing a thermosetting resin, which is a silicon resin having a high hardness resin component and an elastic resin component, and a magnetic powder are not heated so that the thermosetting resin does not completely cure. And a step of forming two green compacts 5 by pressing and molding.
[0034]
At this time, the green compact 5 is formed into a pot shape having an E-shaped cross section having a middle leg portion 7 and an outer leg portion 8 on the back surface portion 6, and the back surface portion 6 is subjected to re-pressure molding. In addition, the green compact 5 is made to be a hard part having a hardness that does not break down, and the middle leg part and the outer leg part are made to be a hard part having a hardness to which the shape of the green compact is broken during re-press molding.
[0035]
Next, the strong hardness portions of the two green compacts 5 support one surface (upper and lower surfaces) of the coil portion 2 and the weak hardness portion is the other surface of the coil portion 2 (the outer peripheral surface and the inner wall surface of the through hole 1). ) Is formed by re-pressing the green compact 5 so that the thermosetting resin is completely cured, and molding the exterior portion 3.
[0036]
At this time, while the back portion 6 of the two green compacts 5 supports the coil portion 2, the two molds 9 press the intermediate portion 7 and the outer leg portion 8 of the weak hardness portion of the green compact 5. The other surface of the coil portion 2 (the outer peripheral surface and the inner wall surface of the through hole 1) is covered and pressed while the weak hardness portion of the green compact 5 is broken.
[0037]
In particular, in this case, the back surface portion 6 (strong hardness portion) of the green compact 5 facing the other surface of the coil portion 2 (inner wall surface of the through hole 1) is blocked in the through hole 1 of the coil portion 2. The back portion 6 (strong hardness portion) of the green compact 5 facing the terminal 4 is buried in a block toward the terminal 4, while the middle leg portion 7 (weak hardness portion) of the green compact 5 is buried. ) And the outer leg portion 8 (weak hardness portion) are broken, covering the other surface of the coil portion 2 (the outer peripheral surface and the inner wall surface of the through hole 1).
[0038]
Moreover, in this exterior part formation process, while making the internal thickness dimension (W) which encloses the coil part 2 smaller than the diameter of the through-hole 1 of the coil part 2, of the exterior part 3 corresponding to the upper part of the coil part 2 A step is provided in which the density of the upper surface portion 11 and the density of the lower surface portion 12 of the exterior portion 3 corresponding to the lower portion of the coil portion 2 are made larger than the density of the intermediate portion 13 of the exterior portion corresponding to the height portion of the coil portion 2. ing.
[0039]
Further, the intermediate portion 13 is provided with an inner intermediate portion 15 corresponding to the inside of the through hole 1 of the coil portion 2 and an outer intermediate portion 14 corresponding to the outer portion of the outer peripheral surface of the coil portion 2. There is also a step of making the density larger than the density of the inner intermediate portion 15.
[0040]
And the exterior part 3 is set so that the density of the upper surface part 11 and the density of the lower surface part 12 are 5.0 to 6.0 g / cm ^3, and the density of the intermediate part 13 is 85% to 98%. Yes.
[0041]
Until the inner thickness dimension (W) (the distance between the coil part 2 and the surface of the exterior part 3) containing the coil part 2 becomes smaller than the diameter of the through hole 1 of the coil part 2 by the above configuration and method, the coil part 2 even if the upper surface portion 11 of the exterior portion 3 corresponding to the upper portion of the outer surface 2 and the lower surface portion 12 of the exterior portion 3 corresponding to the lower portion of the coil portion 2 are formed thin to reduce the overall height. And the density of the lower surface portion 12 are made larger than the density of the intermediate portion 13, the occurrence of magnetic saturation can be suppressed in the upper surface portion 11 and the lower surface portion 12.
[0042]
That is, the inside of the through hole 1 of the coil portion 2 corresponds to the intermediate portion 13 of the exterior portion 3, but the density of the upper surface portion 11 and the lower surface portion 12 of the exterior portion 3 is larger than the density of the intermediate portion 13. Therefore, even if the magnetic flux passing through the inside of the through hole 1 passes through the upper surface portion 11 and the lower surface portion 12 which are smaller than the diameter of the through hole 1, the upper surface portion 11 and the lower surface portion 12 have a higher density than the intermediate portion 13. Thus, the magnetic permeability can be increased by the same amount, and the height can be reduced without causing magnetic saturation in the upper surface portion 11 and the lower surface portion 12.
[0043]
At this time, the intermediate portion 13 has an inner intermediate portion 15 corresponding to the through hole 1 of the coil portion 2 and an outer intermediate portion 14 corresponding to the outer portion of the outer peripheral surface of the coil portion 2. Since the density is larger than the density of the inner intermediate portion 15, the outer intermediate portion 14 can increase the magnetic permeability by the amount higher than the inner intermediate portion 15, and magnetic saturation occurs in the outer intermediate portion 14. Without reducing the size, the lateral dimension can be reduced, and space can be saved during mounting.
[0044]
In particular, the exterior portion 3 has a density of the upper surface portion 11 and a density of the lower surface portion 12 of 5.0 to 6.0 g / cm ³ and a density of the intermediate portion 13 of 85% to 98% of the density. Further, it is possible to suppress the destruction of the exterior part 3 itself due to the internal stress or the like while suppressing the destruction of the coil part 2 without applying the stress to the coil part 2 more than necessary. Moreover, generation | occurrence | production of magnetic saturation can also be suppressed and size reduction can be achieved.
[0045]
Since the exterior portion 3 is a dust core and has a specific composition of the material, it is advantageous in direct current superposition characteristics (because the ratio of iron (Fe) component is large), and iron (Fe ) Suppresses the occurrence of rust due to the inclusion of the component (due to the inclusion of the chromium (Cr) component), can suppress the loss in the high frequency region of 100 kHz or higher (because chromium (cr) ≤ 8 wt%), and damage the magnetic properties And a composite magnetic material with excellent corrosion resistance can be realized.
[0046]
In general, the pressure molding is usually performed by using a mold. However, since the green compact 5 becomes a solid material, the amount of the green compact 5 between the mold 9 and the coil portion 2 is regenerated. It is difficult to fluctuate during pressure molding, and the coating thickness of the exterior part 3 tends to be uniform over the entire periphery of the coil part 2, and the inductance value and the characteristic variation such as saturation characteristics and magnetic loss at the time of DC superimposition of the inductance value are reduced. While being able to suppress, since the coil part 2 can be supported by the green compact 5 itself, the positioning of the coil part 2 becomes accurate and the defective shaping | molding of the exterior part 3 can be prevented. At this time, as the green compact 5, a magnetic powder and a binder containing a thermosetting resin are mixed and pressurized, and a silicon resin having a high hardness resin component and an elastic resin component is used as the thermosetting resin. Therefore, the exterior part which has the intensity | strength with which hardness and the brittleness were balanced can be formed, and the defect of an exterior part can be reduced.
[0047]
Further, since the green compact 5 is re-press-molded to cover the coil portion 2, the coil portion 2 can be accurately covered, and the space between the green compact 5 and the coil portion 2 is filled without any gap. The magnetic efficiency can be improved by reducing the magnetic gap.
[0048]
In particular, since the strong hardness part of the green compact 5 firmly supports one surface of the coil part 2, the coil part 2 is hardly displaced during re-press molding, and the weak hardness part of the green compact 5 takes its shape. The other surface of the coil portion 2 can be easily covered while being crushed, and the coating thickness of the exterior portion 3 can be easily made uniform over the entire periphery of the coil portion 2, thereby suppressing variation in characteristics.
[0049]
The shape of the green compact 5 is an E-shape having a middle leg portion 7 and an outer leg portion 8 on the back surface portion 6, and the back surface portion 6 is a hardened portion, and the middle leg portion 7 and the outer leg portion are also formed. Since 8 is a weak hardness part, it is even more difficult for a position shift to occur with respect to the strong hardness part of the green compact 5, and the other surface of the coil part 2 can be covered easily, and variation in characteristics can be suppressed. .
[0050]
As described above, according to the embodiment of the present invention, the coating thickness of the exterior portion 3 is likely to be uniform over the entire periphery of the coil portion 2, and not only the characteristic variation can be suppressed, but also the upper surface portion 11 of the exterior portion 3. The lower surface portion 12 can increase the magnetic permeability by a larger density than the intermediate portion 13, and can reduce the height without causing magnetic saturation in the upper surface portion 11 and the lower surface portion 12. is there.
[0051]
In the embodiment of the present invention, the shape of the green compact 5 is an E shape. However, the length of the middle leg portion 7 is longer than the length of the outer leg portion 8 without departing from the spirit of the present invention. It may be longer, shorter, or other shapes. In particular, a T-shape in which only the middle leg portion 7 is formed on the back surface portion 6 and a U-shape in which only the outer leg portion 8 is formed are regarded as a substantially E shape.
[0052]
Further, the positional relationship between the coil part 2 and the green compact 5 is such that even if the strong hardness parts of the two green compacts 5 do not support one surface of the coil part 2, at least one of the green compacts 5 has a high hardness. The part should just support one surface of the coil part 2. FIG. At this time, the density of the strong hardness portion of the E-shaped green compact 5 may be larger than the density of the weak hardness portion.
[0053]
Furthermore, the coil part 2 may be an edgewise winding wound with a rectangular wire in addition to a round wire. In this case, the space factor can be improved and a large current can be handled. If the adjacent rectangular wires are brought into close contact with each other so that the exterior portion 3 is not formed between the rectangular wires, the exterior portion 3 is not formed between the rectangular wires, and the generation of magnetic flux around the rectangular wire is suppressed and the loss Can be reduced.
[0054]
As another example, as shown in FIGS. 7 and 8, one green compact 5 has a back surface portion 6 of a hardened portion supporting one surface of the coil portion 2, and the other green compact 5 is a coil. The intermediate leg portion 7 is inserted into the through hole 1 of the portion 2 so as to be re-pressurized, or the minute irregularities 10 are provided at the tips of the middle leg portion 7 and the outer leg portion 8 of the two green compacts 5. At the same time, re-pressure molding is performed such that the middle leg portion 7 and the outer leg portion 8 of the two green compacts 5 face each other, or a dividing groove for dividing is provided on the back surface portion 6 of the green compact 5. Further, re-pressure molding may be performed, and both of them can more easily cover the other surface of the coil portion 2 and suppress variation in characteristics.
[0055]
At this time, in the embodiment of the present invention, the strong hardness part of the green compact 5 supports one surface of the coil part 2 before or during the re-pressure molding. Even later, it is desirable that the strong hardness portion of the green compact supports one surface of the coil portion 2.
[0056]
【The invention's effect】
As described above, the present invention corresponds to the upper part of the coil part until the inner thickness dimension (distance between the coil part and the surface of the exterior part) enclosing the coil part becomes smaller than the diameter of the through hole of the coil part. Even if the upper surface portion of the exterior portion and the lower surface portion of the exterior portion corresponding to the lower portion of the coil portion are formed thin to reduce the overall height, the density of the upper surface portion and the density of the lower surface portion are more than the density of the intermediate portion. Therefore, it is possible to suppress the occurrence of magnetic saturation in the upper surface portion and the lower surface portion.
[0057]
That is, the inside of the through-hole of the coil portion corresponds to the intermediate portion of the exterior portion, but the density of the upper surface portion and the lower surface portion of the exterior portion is larger than the density of this intermediate portion, so it passes through the inside of the through-hole. Even if the magnetic flux passing through the upper surface portion and the lower surface portion, which is smaller than the diameter of the through-hole, the magnetic permeability can be increased by the amount higher in density in the upper surface portion and the lower surface portion than in the intermediate portion. Thus, it is possible to provide a coil component that is reduced in height without causing magnetic saturation in the portion.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a coil component according to an embodiment of the present invention. FIG. 2 is a perspective view. FIG. 3 is a diagram showing a part of the manufacturing process. FIG. 5 is a perspective view of a coil portion to which a terminal which is the main part is connected. FIG. 6 is a perspective view before forming the terminal which is the main part. FIG. 7 is another manufacture according to the embodiment of the invention. FIG. 8 is a diagram showing a part of the manufacturing process of still another coil component in the embodiment of the present invention. FIG. 9 is a perspective view of a conventional coil component. [Fig. 11] Cross-sectional view showing a part of the manufacturing process [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Through-hole 2 Coil part 3 Exterior part 4 Terminal 5 Green compact 6 Back part 7 Middle leg part 8 Outer leg part 9 Mold 10 Micro uneven part 11 Upper surface part 12 Lower surface part 13 Intermediate part 14 Outer intermediate part 15 Inner intermediate part

Claims

A dust magnet comprising a coil part having a through hole and an exterior part including the coil part, wherein the exterior part is formed by mixing a binder containing a thermosetting resin and magnetic powder and press-molding it. a core, with inclusion thickness dimension of the outer portion of the coil portion is contained is smaller than the diameter of the through hole of the coil unit, an intermediate density of the top portion and bottom portion of the outer portion of the outer portion Coil parts larger than the density of the part.

The density of the outer side intermediate part corresponding to the outer side part of the outer peripheral surface of the said coil part is larger than the density of the inner side intermediate part corresponding to the inside of the through-hole of the said coil part . Coil parts.

The outer part, together with the density of the top portion and bottom portion are 5.0~6.0g / cm ^3, claim 1 density of the intermediate portion is 85% to 98% of the density of the top portion and a bottom portion The coil component described.

The coil component according to claim 1, wherein the coil portion is an edgewise winding wound with a rectangular wire, and the adjacent rectangular wires are in close contact with each other.

The coil component according to claim 1, wherein the thermosetting resin is a silicon resin having a high-hardness resin component and an elastic resin component.