JP2004228296A

JP2004228296A - Air core coil

Info

Publication number: JP2004228296A
Application number: JP2003013517A
Authority: JP
Inventors: Akira Okada; 章岡田; Satoru Inoue; 井上　　悟
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2003-01-22
Filing date: 2003-01-22
Publication date: 2004-08-12

Abstract

【課題】測定誤差が小さく、また作製が容易な空芯コイルを得ることを目的とする。
【解決手段】空芯コイルは、絶縁性基板２と、この絶縁性基板２に設けられたコイル本体３とを備えている。絶縁性基板２は基板開口部４を有している。コイル本体３は、絶縁性基板２に付着された導電膜である。絶縁性基板２の表面８及び裏面９には、溝部２０が形成され、溝部２０の内面に導電膜が付着されている。コイル本体３は、絶縁性基板２の全面に付着された導電膜をポリッシングにより一部除去して各溝部２０内に残すことにより形成される。各溝部２０間の仕切部２１は、先端部２２に形成された平面２３の幅Ｗ１が基部２４の幅Ｗ２よりも小さくなっている。
【選択図】図４An object of the present invention is to obtain an air-core coil which has a small measurement error and is easy to manufacture.
An air-core coil includes an insulating substrate (2) and a coil body (3) provided on the insulating substrate (2). The insulating substrate 2 has a substrate opening 4. The coil main body 3 is a conductive film attached to the insulating substrate 2. A groove 20 is formed on the front surface 8 and the back surface 9 of the insulating substrate 2, and a conductive film is attached to the inner surface of the groove 20. The coil body 3 is formed by removing a part of the conductive film attached to the entire surface of the insulating substrate 2 by polishing and leaving the conductive film in each groove 20. In the partition 21 between the grooves 20, the width W1 of the plane 23 formed on the distal end 22 is smaller than the width W2 of the base 24.
[Selection diagram] Fig. 4

Description

【０００１】
【発明の属する技術分野】
この発明は、例えば被測定導体を流れるインパルス大電流等を測定する電流センサに用いられる空芯コイルに関するものである。
【０００２】
【従来の技術】
空芯コイルは、巻芯に鉄心等の強磁性体を有しないコイルであり、磁気飽和にならない性質がある。従って、空芯コイルを被測定導体に流れる電流測定のための電流センサに用いると、幅広い電流範囲の測定が可能となる。また、電流センサの空芯コイルには、外部電磁界による測定誤差を抑制するためにロゴスキーコイルが用いられる。ロゴスキーコイルは、導線がソレノイド状に巻き進められ、その巻き終わりから巻き始めまで戻されて構成されたコイルである。
【０００３】
従来のロゴスキーコイルは、平面プリント回路板に金を堆積させて構成されている。このロゴスキーコイルは、平面プリント回路板に構成されているので、ほとんど完全に軸方向に対称に作製できる（例えば、特許文献１参照）。
【０００４】
【特許文献１】
特開平６−１７６９４７号公報
【０００５】
【発明が解決しようとする課題】
このように従来の空芯コイルを作製する場合、平面プリント回路板に金堆積物をパターン配置する必要があるので手間がかかる。
また、従来の空芯コイルを電流センサに用いる場合、被測定導体の軸周りに沿って見たときに、ロゴスキーコイルの巻き進みコイルによって囲まれる面積と巻き戻しコイルによって囲まれる面積とが異なっているので、それぞれに発生する誘導起電力の大きさに差が生じ、測定誤差が大きくなる。
【０００６】
そこでこの発明は、上記のような問題点を解決することを課題とするもので、測定誤差が小さく、また作製が容易な空芯コイルを得ることを目的とする。
【０００７】
【課題を解決するための手段】
この発明に係る空芯コイルは、表面と、裏面と、表面及び裏面を貫通し、被測定導体が通される基板開口部とを有する絶縁性基板、表面及び裏面での基板開口部の周囲で略放射状に設けられた複数の導体部と、表面の各導体部及び裏面の各導体部のそれぞれの端部に接続された複数の接続導体部とを有し、各導体部及び各接続導体部によりコイル状に構成されたコイル本体を備え、表面及び裏面の少なくとも一方には、基板開口部の周囲で略放射状に延びる複数の溝部と複数の仕切部とが交互に配列され、導体部が各溝部にそれぞれ設けられており、仕切部の先端部の幅は、仕切部の基部の幅よりも小さくなっている。
【０００８】
【発明の実施の形態】
以下、この発明の実施の形態を図面を参照しながら説明する。
実施の形態１．
図１は、この発明の実施の形態１による空芯コイルを示す正面図であり、図２は、図１の接続点７付近のコイル本体３を示す部分拡大図である。図において、空芯コイル１は、樹脂等の非磁性体で作製された絶縁性基板２と、この絶縁性基板２に設けられたコイル本体３とを備えている。絶縁性基板２は、被測定導体が通される円形状の基板開口部４を中央に有した円板である。コイル本体３は、基板開口部４の外周に沿って導線が巻回されるように形成された巻き進みコイル部５及び巻き戻しコイル部６を有している。
【０００９】
巻き進みコイル部５と巻き戻しコイル部６とは接続点７で電気的に直列に接続されている。巻き進みコイル部５及び巻き戻しコイル部６のそれぞれの導線には、被測定導体に流れる電流に対応した誘導起電力が発生するようになっている。巻き進みコイル部５及び巻き戻しコイル部６は、この誘導起電力が電気的に同じ向きになるように巻回されている。また、巻き進みコイル部５及び巻き戻しコイル部６を構成する導線は、絶縁性基板２にコイル状に付着された銅の導電膜である。
即ち、空芯コイル１は、導体が巻き進められた巻き進みコイル部５と、巻き進みコイル部５の終端部に接続されて導線が巻き進みコイル部５に沿って巻き戻された巻き戻しコイル部６とから構成されるロゴスキーコイルである。
【００１０】
絶縁性基板２には、コイル本体３の引出部３０、３１に電気的に接続された信号処理回路３２が取り付けられている。信号処理回路３２は、コイル本体３に発生する誘導電流を積分処理する回路である。誘導電流は、被測定導体に流れる電流波形の微分値としてコイル本体３に発生し、信号処理回路３２の積分処理により被測定導体の電流波形が復元される。
【００１１】
絶縁性基板２の表面８及び裏面９には、導電膜である複数の第１表面導体部１０（導体部）及び導電膜である複数の第１裏面導体部１１（導体部）がそれぞれ付着されている。また、絶縁性基板２には、絶縁性基板２を貫通する複数の接続導体部１２が設けられている。巻き進みコイル部５は、複数の第１表面導体部１０及び複数の第１裏面導体部１１が各接続導体部１２を介して電気的に直列に接続されてコイル状に形成されたものである。
【００１２】
絶縁性基板２の表面８及び裏面９にはまた、導電膜である複数の第２表面導体部１５（導体部）及び導電膜である複数の第２裏面導体部１６（導体部）がそれぞれ付着されている。各第２表面導体部１５は、各第１表面導体部１０の間に配置され、各第２裏面導体部１６は、各第１裏面導体部１１の間に配置されている。また、絶縁性基板２には、絶縁性基板２を貫通する複数の接続導体部１７が設けられている。巻き戻しコイル部６は、複数の第２表面導体部１５及び複数の第２裏面導体部１６が各接続導体部１７を介して電気的に直列に接続されてコイル状に形成されたものである。なお、図１及び図２において、裏面９に形成された導電膜は、破線で示している。
【００１３】
各第１表面導体部１０は、内側端部１０ａが基板開口部４に近い側に配置され、外側端部１０ｂが基板開口部４から遠い側に配置されるように、基板開口部４の周囲で略放射状に一定ピッチでそれぞれ配列されている。
【００１４】
各第１裏面導体部１１は、接続導体部１２への接続のために基板開口部４から離れた側でそれぞれ屈曲されている。また、各第１裏面導体部１１は、内側端部１１ａが基板開口部４に近い側に配置され、外側端部１１ｂが基板開口部４から遠い側に配置されるように、基板開口部４の周囲で略放射状に一定ピッチで配列されている。
【００１５】
各第２表面導体部１５は、表面８で基板開口部４の周囲に略放射状に第１表面導体部１０と交互になるように一定ピッチで配列されている。また、各第２表面導体部１５は、各内側端部１５ａ及び各外側端部１５ｂがそれぞれ各内側端部１０ａ及び各外側端部１０ｂよりも基板開口部４に近い位置になるように配置されている。
【００１６】
各第２裏面導体部１６は、接続導体部１７への接続のために基板開口部４に近い側で屈曲されている。また、各第２裏面導体部１６は、裏面９で基板開口部４の周囲に略放射状に第１裏面導体部１１と交互になるように一定ピッチで配列されている。また、各第２裏面導体部１６は、各内側端部１６ａ及び各外側端部１６ｂがそれぞれ各内側端部１１ａ及び各外側端部１１ｂよりも基板開口部４に近い位置になるように配置されている。
【００１７】
図１に示すように、各第１表面導体部１０及び第１裏面導体部１１の略放射状部分は互いに対向されて配置され、各第２表面導体部１５及び第２裏面導体部１６の略放射状部分は互いに対向されて配置されている。
各第１表面導体部１０及び各第１裏面導体部１１は、絶縁性基板２の厚さ方向に沿って見たとき、各内側端部１０ａと各内側端部１１ａとが重なり、各外側端部１０ｂと各外側端部１１ｂとが重なるように配列されている。また、各第２表面導体部１５及び各第２裏面導体部１６は、絶縁性基板２の厚さ方向に沿って見たとき、各内側端部１５ａと各内側端部１６ａとが重なり、各外側端部１５ｂと各外側端部１６ｂとが重なるように配列されている。なお、図１においては、分かり易くするために、互いに対向する略放射状部分を並べて示している。
【００１８】
接続導体部１２は、図１において互いに重なる各内側端部１０ａ及び１１ａを電気的に接続する複数の第１内側接続導体部１３と、図１において互いに重なる各外側端部１０ｂ及び１１ｂを電気的に接続する複数の第１外側接続導体部１４とからなっている。
【００１９】
接続導体部１７は、各内側端部１５ａ及び各内側端部１６ａを電気的に接続する複数の第２内側接続導体部１８と、各外側端部１５ｂ及び各外側端部１６ｂを電気的に接続する複数の第２外側接続導体部１９とからなっている。
【００２０】
図３は、図１の基板開口部４の外周に沿って（図１の矢印２７の向きに沿って）見たときの絶縁性基板２、巻き進みコイル部５及び巻き戻しコイル部６を示す配置図である。図において、絶縁性基板２の表面８及び裏面９には、複数の溝部２０がそれぞれ形成されている。各溝部２０は、基板開口部４の周囲で略放射状に延びており、基板開口部４の周方向に沿って配列されている。第１表面導体部１０、第１裏面導体部１１、第２表面導体部１５及び第２裏面導体部１６は、各溝部２０の内面に付着されている。
また、接続導体部１２及び接続導体部１７は、絶縁性基板２の厚さ方向に沿って絶縁性基板２を貫通する貫通孔の内面に形成された銅の導電膜、即ち金属スルーホールである。
【００２１】
また、第２内側接続導体部１８は、第１内側接続導体部１３よりも基板開口部４に近い側に配置され、第２外側接続導体部１９は、第１外側接続導体部１４よりも基板開口部４に近い側、かつ第１内側接続導体部１３よりも基板開口部４から遠い側に配置されている。
【００２２】
即ち、巻き進みコイル部５及び巻き戻しコイル部６は、基板開口部４の外周に沿って見たときに、巻き進みコイル部５の導線によって囲まれる領域、即ち第１表面導体部１０、第１裏面導体部１１、第１内側接続導体部１３及び第１外側接続導体部１４によって囲まれる領域（以下、巻き進みコイル部５の断面領域という）と、巻き戻しコイル部６の導線によって囲まれる領域、即ち第２表面導体部１５、第２裏面導体部１６、第２内側接続導体部１８及び第２外側接続導体部１９によって囲まれる領域（以下、巻き戻しコイル部６の断面領域という）とが、大部分で互いに重なって配置されている。さらに、巻き進みコイル部５の断面領域の面積と巻き戻しコイル部６の断面領域の面積とがほぼ同一となっている。
【００２３】
図４は、図３のＩＶ−ＩＶ線に沿った断面図である。図において、互いに隣接する溝部２０の間には、仕切部２１が形成されている。仕切部２１は、各溝部２０の形成により絶縁性基板２の一部が残されて形成されたものである。各仕切部２１の先端部２２には、絶縁性基板２の厚さ方向に対して垂直な平面２３がそれぞれ形成されている。平面２３の幅Ｗ１は、その仕切部２１の基部２４の幅Ｗ２よりも小さくなっている。即ち、平面２３の溝部２０の配列方向に沿った幅Ｗ１は、基部２４の溝部２０の配列方向に沿った幅Ｗ２よりも小さくなっている。ここでは、各溝部２０の解放側が広げられて仕切部２１の先端部２２にテーパ面２５が形成されることにより、各溝部２０の底部に隣接した基部２４の幅Ｗ２よりも小さい幅Ｗ１の平面２３が形成されている。平面２３には、導電膜は付着されていない。従って、互いに隣り合う溝部２０に付着された導電膜、即ち第１表面導体部１０及び第２表面導体部１５、並びに第１裏面導体部１１及び第２裏面導体部１６は、互いに絶縁されている。
【００２４】
次に、動作について説明する。
被測定導体に電流が流されると、巻き進みコイル部５の断面領域及び巻き戻しコイル部６の断面領域を磁束が通され、コイル本体３に誘導電流が発生する。この誘導電流は、図２に示した矢印の向きに流れるので、各箇所で発生する誘導電流が電気的に互いに相殺されることはない。コイル本体３の導線を流れる誘導電流は、信号処理回路３２において積分処理されて、被測定導体を流れる電流波形が算出される。
【００２５】
次に、作製方法について説明する。
図５は、図４の絶縁性基板２の作製途中の形状を示す縦断面図（基板開口部４の周方向に沿った断面図）である。まず、熱膨張の小さいエンジニアリングプラスチックを、圧縮成形法あるいは注形法等のモールド法により図５に示すような断面形状の板に成形する。即ち、平面２３の幅Ｗ１よりもさらに小さな幅の頂部３３を有する複数の仕切部２１と複数の溝部２０とをエンジニアリングプラスチックの板の表面及び裏面に交互に形成する。
【００２６】
その後、表面及び裏面の溝部２０の端部間にエンジニアリングプラスチックの板を貫通する複数の貫通孔を形成した後、この板全面及び貫通孔の内面に乾式めっきあるいは湿式めっきによって導電膜を付着させる。これにより、均一な厚さで導電膜を板全面及び貫通孔の内面に付着させることができる。
それから、エンジニアリングプラスチックの板の表面、裏面、外側面及び基板開口部４の内側面にポリッシングを行い、溝部２０の内面及び貫通孔の内面を除く導電膜を除去する。このとき、エンジニアリングプラスチックの板の表面及び裏面では、仕切部２１の頂部３３が導電膜とともにポリッシング位置４０まで除去される。これにより、導電膜が溝部２０ごとに分離されて各導体部となる。コイル本体３は、溝部２０の内面及び貫通孔の内面に残された導電膜により構成され、空芯コイル１が完成する。
【００２７】
このように頂部３３の幅が平面２３の幅Ｗ１よりも小さくなっているので、導電膜をポリッシングにより容易に除去することができる。また、仕切部２１に形成された平面２３の幅Ｗ１が基部２４の幅Ｗ２よりも小さくなっているので、除去される導電膜の量を少なくでき、導電膜を短時間で除去することができる。従って、大量に、しかも安価に空芯コイル１を製造することができる。
【００２８】
また、第２内側接続導体部１８は、第１内側接続導体部１３よりも基板開口部４に近い側に配置され、第２外側接続導体部１９は、第１外側接続導体部１４よりも基板開口部４に近い側、かつ第１内側接続導体部１３よりも基板開口部４から遠い側に配置されているので、基板開口部４の周方向に沿って見たときに、コイル本体３での巻き進みコイル部５及び巻き戻しコイル部６のそれぞれの断面領域の大部分が互いに重なった状態で、各断面領域の面積をほぼ同一とすることができる。このことから、巻き進みコイル部５及び巻き戻しコイル部６に誘導起電力を発生させる磁束をさらに共通化することができ、また各コイルに発生する誘導起電力の大きさをほぼ等しくすることができる。従って、電流センサに空芯コイル１を用いると、測定感度を向上させることができ、また測定誤差も小さくすることができる。
【００２９】
また、コイル本体３の導線は、ほとんど完全に基板開口部４の軸線に関して対称に、かつ均一に形成されることが可能であるので、さらに測定感度を向上させ、測定誤差を小さくすることができる。
【００３０】
また、絶縁性基板２は、モールド法により成形されているので、絶縁性基板２の寸法及び形状に制限がなく、コイル本体３の形状も容易に所望の形状にすることができる。
【００３１】
実施の形態２．
図６は、この発明の実施の形態２による空芯コイルの構成を示す正面図である。また、図７は、図６の接続点７付近のコイル本体３を示す部分拡大図である。図において、図１の空芯コイル１に相当する部材あるいは部位については同一符号を付して示し、ここでは、その説明を省略する。
【００３２】
この実施の形態２による空芯コイル１のコイル本体３は、絶縁性基板２に設けられて互いに直列に接続された巻き進みコイル部５及び巻き戻しコイル部６を有している。
【００３３】
図６に示すように、絶縁性基板２の厚さ方向に沿って見たとき、巻き進みコイル部５の各第１表面導体部１０及び各第１裏面導体部１１により鋸歯状の模様が構成されている。また、巻き戻しコイル部６の各第２表面導体部１５及び各第２裏面導体部１６によっても鋸歯状の模様が構成され、巻き戻しコイル部６の鋸歯状の模様は、巻き進みコイル部５の鋸歯状の模様の内側に配置されている。巻き進みコイル部５及び巻き戻しコイル部６の導線によってそれぞれ囲まれる鋸歯状の領域は、巻き進みコイル部５の正面領域及び巻き戻しコイル部６の正面領域である。
【００３４】
即ち、絶縁性基板２の厚さ方向に沿って視たとき、第２外側接続導体部１９を介して互いに接続された第２表面導体部１５及び第２裏面導体部１６の各内側端部１５ａ、１６ａは、各第２表面導体部１５及び各第２裏面導体部１６の配列方向に沿って互いに離間されて配置されている。さらに、第２内側接続導体部１８を介して互いに接続された第２表面導体部１５及び第２裏面導体部１６の各外側端部１５ｂ、１６ｂも、各第２表面導体部１５及び各第２裏面導体部１６の配列方向に沿って互いに離間されて配置されている。
【００３５】
また、絶縁性基板２の厚さ方向に沿って視たとき、第１外側接続導体部１４を介して互いに接続された第１表面導体部１０及び第１裏面導体部１１の各内側端部１０ａ、１１ａは、各第１表面導体部１０及び各第１裏面導体部１１の配列方向に沿って互いに離間されて配置されている。さらに、第１内側接続導体部１３を介して互いに接続された第１表面導体部１０及び第１裏面導体部１１の各外側端部１０ｂ、１１ｂも、各第１表面導体部１０及び各第１裏面導体部１１の配列方向に沿って互いに離間されて配置されている。
【００３６】
さらに、各第２表面導体部１５及び各第２裏面導体部１６の内側端部１５ａ及び１６ａは、各第１表面導体部１０及び各第１裏面導体部１１の内側端部１０ａ及び１１ａよりも基板開口部４に近い側に配置されている。また、各第２表面導体部１５及び各第２裏面導体部１６の外側端部１５ｂ及び１６ｂは、各第１表面導体部１０及び各第１裏面導体部１１の外側端部１０ｂ及び１１ｂよりも基板開口部４に近い側に配置され、かつ各第１表面導体部１０及び各第１裏面導体部１１の内側端部１０ａ及び１１ａよりも基板開口部４から遠い側に配置されている。
【００３７】
第１表面導体部１０及び第１裏面導体部１１が、互いに重なっている外側端部１０ｂ及び外側端部１１ｂを始点としたベクトルであると考えると、そのベクトルの合成方向に基板開口部４の中心点が存在するように、各第１表面導体部１０及び各第１裏面導体部１１は設けられている。
第２表面導体部１５及び第２裏面導体部１６も同様に、互いに重なっている外側端部１５ｂ及び外側端部１６ｂを始点としたベクトルであると考えると、そのベクトルの合成方向に基板開口部４の中心点が存在するように、各第２表面導体部１５及び各第２裏面導体部１６は設けられている。
他の構成、作製方法及び動作は実施の形態１と同様である。
【００３８】
ここで、巻き進みコイル部５及び巻き戻しコイル部６での誘導電流は、被測定導体からの磁界だけでなく、巻き進みコイル部５及び巻き戻しコイル部６のそれぞれの正面領域を通る外部電磁界によっても発生する。外部電磁界による誘導電流は、電流センサの測定誤差の原因となる。従って、外部電磁界による誘導電流を互いに相殺させるために、巻き進みコイル部５及び巻き戻しコイル部６のそれぞれの正面領域の面積が同一に近いほうがよい。
【００３９】
従って、実施の形態２による空芯コイル１によれば、実施の形態１と同様の効果を奏するとともに、巻き進みコイル部５の正面領域の面積と巻き戻しコイル部３１の正面領域の面積との面積差をさらに小さくすることができ、外部電磁界による測定誤差をさらに小さくすることができる。
【００４０】
なお、上記実施の形態１及び２では、ポリッシングにより導電膜を除去しているが、例えば、導電膜を除去したい部分にレジスト剤を塗布しておき、絶縁性基板２の全面に導電膜を付着させた後にレジスト剤と共に導電膜を除去してもよいし、あるいはレーザー等により除去したい導電膜をカットしてもよい。
【００４１】
また、上記実施の形態１及び２では、絶縁性基板２は、モールド法による成形に限定されず、例えば切削により成形しても構わない。
【００４２】
また、上記実施の形態１及び２では、電流センサの測定感度をさらに向上させるために、複数枚の空芯コイル１を接続して用いてもよい。この場合、信号処理回路３２は、複数枚の空芯コイル１に対して１つ設けられる。各空芯コイル１は、基板開口部４を揃えて並べられ、各コイル本体３を互いに接続するために、表面８及び裏面９の一方に引出部３０からの接続端子が設けられ、他方に引出部３１からの接続端子が設けられる。また、各接続端子同士の接続を容易にするために、互いの接続端子に凹部及び凸部がそれぞれ形成され、この凹部及び凸部が嵌め合わされることにより各接続端子は互いに接続される。
【００４３】
また、上記実施の形態１及び２では、各第２内側接続導体部１８及び各第１外側接続導体部１４は、貫通孔の内面に付着された導電膜であるが、実施の形態１の変形例を示す図８のように、基板開口部４の内側面及び絶縁性基板２の外側面にそれぞれ形成された複数の内側溝部３４及び外側溝部３５の内面に付着された導電膜であってもよい。これにより、絶縁性基板２に形成される貫通孔の数を少なくすることができ、さらに容易に各第２内側接続導体部１８及び各第１外側接続導体部１４を構成することができる。この場合、各内側溝部３４間及び各外側溝部３５間の仕切部３６の先端部（各溝部３４及び３５の解放側）には、テーパ面３７が形成される。
また、貫通孔、内側溝部３４及び外側溝部３５を混在させて各第２内側接続導体部１８及び各第１外側接続導体部１４を構成しても構わない。
【００４４】
実施の形態３．
図９は、この発明の実施の形態３による空芯コイルの構成を示す部分斜視図である。図において、実施の形態１又は２での絶縁性基板２の外側面及び基板開口部４の内側面には、導電膜である導電性シールド４１が付着されている。導電性シールド４１は、例えば銅等の導電性金属が電気的に接地されたものである。
【００４５】
導電性シールド４１は、上記実施の形態１での空芯コイル１の作製途中において、絶縁性基板２の全面に導電膜を付着させた後のポリッシングの際、絶縁性基板２の外側面及び基板開口部４の内側面のポリッシングを行わずに導電膜を残すことにより形成される。
【００４６】
ここで、絶縁性基板２に設けられたコイル本体３（図１参照）の接続導体部１２及び１７（図２参照）は、貫通孔の内面に付着された導電膜であり、導電性シールド４１に対して短絡しないようになっている。他の構成は実施の形態１と同様である。
【００４７】
このように絶縁性基板２の外側面及び基板開口部４の内側面に導電性シールド４１が付着されているので、コイル本体３（図１参照）での外部電磁界による誘導起電力の発生を導電性シールド４１によって抑制することができる。ここで、導電性シールド４１は、接地されているので、外部電磁界により発生した誘導起電力によって帯電することはない。
【００４８】
実施の形態４．
図１０は、この発明の実施の形態３による空芯コイルの構成を示す部分斜視図である。図において、実施の形態１あるいは２での絶縁性基板２の表面、裏面、外側面及び基板開口部４の内側面には、絶縁性材料の絶縁層４２が設けられている。絶縁層４２の外周面には、導電膜である導電性シールド４３が付着されている。即ち、コイル本体３（図１参照）及び絶縁性基板２は、絶縁層４２を介して導電性シールド４３に覆われている（即ち、囲まれている）。導電性シールド４３は、例えば銅等の導電性金属が電気的に接地されたものである。他の構成は実施の形態１と同様である。
【００４９】
このようにコイル本体３（図１参照）が導電性シールド４３によって囲まれているので、コイル本体３（図１参照）での外部電磁界による誘導起電力の発生を導電性シールド４１によってさらに抑制することができる。
【００５０】
なお、絶縁層４２は、絶縁性基板２を完全に囲う必要はなく、導電性シールド４３が内部のコイル本体３（図１参照）に接触しない状態に保たれていれば、例えば格子状、あるいは複数の支持突起であってもよい。
【００５１】
また、実施の形態３及び４では、導電性シールド４１及び４３は導電膜であるが、例えば金属板であってもよい。
また、実施の形態１による空芯コイルに代えて、実施の形態２による空芯コイルを用いると、電流センサの外部電磁界による測定誤差をさらに小さくすることができる。
【００５２】
【発明の効果】
以上の説明から明らかなように、この発明に係る空芯コイルは、表面及び裏面の少なくとも一方には、基板開口部の周囲で略放射状に延びる複数の溝部と複数の仕切部とが交互に配列され、導体部が各溝部にそれぞれ設けられており、仕切部の先端部の幅は、仕切部の基部の幅よりも小さくなっているので、表面あるいは裏面に導電膜を付着させて溝部内に導電膜を導体部として残す方法で、除去される導電膜の量を少なくでき、導体部を短時間で形成することができる。
【図面の簡単な説明】
【図１】図１は、この発明の実施の形態１による空芯コイルを示す正面図である。
【図２】図１の接続点付近のコイル本体を示す部分拡大図である。
【図３】図１の基板開口部の外周に沿って見たときの絶縁性基板、巻き進みコイル部及び巻き戻しコイル部を示す配置図である。
【図４】図３のＩＶ−ＩＶ線に沿った断面図である。
【図５】図４の絶縁性基板の作製途中の形状を示す基板開口部の周方向に沿った断面図である。
【図６】この発明の実施の形態２による空芯コイルの構成を示す正面図である。
【図７】図６の接続点付近のコイル本体を示す部分拡大図である。
【図８】この発明の実施の形態１の変形例による空芯コイルを示す部分斜視図である。
【図９】この発明の実施の形態３による空芯コイルの構成を示す部分斜視図である。
【図１０】この発明の実施の形態４による空芯コイルの構成を示す部分斜視図である。
【符号の説明】
１空芯コイル、２絶縁性基板、３コイル本体、４基板開口部、５巻き進みコイル部、６巻き戻しコイル部、８表面、９裏面、１０第１表面導体部（表面導体部）、１１第１裏面導体部（裏面導体部）、１２，１７接続導体部、１３第１内側接続導体部（内側接続導体部）、１４第１外側接続導体部（外側接続導体部）、１５第２表面導体部（表面導体部）、１６第２裏面導体部（裏面導体部）、１８第２内側接続導体部（内側接続導体部）、１９第２外側接続導体部（外側接続導体部）、２０溝部、２１，３６仕切部、２２先端部、２４基部、３３頂部、３４内側溝部、３５外側溝部。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an air-core coil used for a current sensor for measuring, for example, a large impulse current flowing through a conductor to be measured.
[0002]
[Prior art]
An air-core coil is a coil that does not have a ferromagnetic material such as an iron core in a winding core, and has a property of not causing magnetic saturation. Therefore, when the air-core coil is used as a current sensor for measuring the current flowing through the conductor to be measured, a wide current range can be measured. A Rogowski coil is used for the air-core coil of the current sensor in order to suppress a measurement error due to an external electromagnetic field. The Rogowski coil is a coil in which a conductive wire is wound in a solenoid shape and returned from the end to the beginning of winding.
[0003]
Conventional Rogowski coils are constructed by depositing gold on a planar printed circuit board. Since this Rogowski coil is formed on a flat printed circuit board, it can be manufactured almost completely symmetrically in the axial direction (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-6-176947
[0005]
[Problems to be solved by the invention]
As described above, when manufacturing the conventional air-core coil, it is necessary to arrange the gold deposit on the planar printed circuit board in a pattern, which is troublesome.
In addition, when a conventional air-core coil is used for a current sensor, when viewed along the axis of the conductor to be measured, the area surrounded by the leading coil of the Rogowski coil differs from the area surrounded by the rewind coil. Therefore, a difference occurs in the magnitude of the induced electromotive force generated in each case, and the measurement error increases.
[0006]
Therefore, an object of the present invention is to solve the above-described problems, and an object of the present invention is to obtain an air-core coil that has a small measurement error and is easy to manufacture.
[0007]
[Means for Solving the Problems]
An air-core coil according to the present invention is an insulating substrate having a front surface, a back surface, and a substrate opening that penetrates the front and back surfaces and through which a conductor to be measured is passed, around the substrate opening on the front and back surfaces. A plurality of conductors provided in a substantially radial manner, and a plurality of connection conductors connected to respective ends of the conductors on the front surface and the conductors on the back surface; A plurality of grooves and a plurality of partitions extending substantially radially around the substrate opening are alternately arranged on at least one of the front surface and the back surface, and the conductor portion is provided on at least one of the front surface and the back surface. The width of the tip of the partition is smaller than the width of the base of the partition.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a front view showing an air-core coil according to Embodiment 1 of the present invention, and FIG. 2 is a partially enlarged view showing a coil main body 3 near a connection point 7 in FIG. In the figure, an air-core coil 1 includes an insulating substrate 2 made of a non-magnetic material such as a resin, and a coil body 3 provided on the insulating substrate 2. The insulating substrate 2 is a disk having a circular substrate opening 4 at the center through which the conductor to be measured is passed. The coil body 3 has a winding coil section 5 and a rewind coil section 6 formed so that a conductive wire is wound along the outer periphery of the substrate opening 4.
[0009]
The winding coil section 5 and the rewind coil section 6 are electrically connected in series at a connection point 7. An induced electromotive force corresponding to the current flowing through the conductor to be measured is generated in each of the lead wires of the winding coil section 5 and the rewind coil section 6. The winding coil section 5 and the rewind coil section 6 are wound such that the induced electromotive force is in the same electrical direction. In addition, the conductive wires forming the winding advance coil portion 5 and the rewinding coil portion 6 are copper conductive films adhered to the insulating substrate 2 in a coil shape.
That is, the air-core coil 1 includes a winding coil portion 5 in which a conductor is wound, and a rewind coil connected to an end portion of the winding coil portion 5 and in which a conductor is wound and wound along the coil portion 5. And a Rogowski coil composed of a part 6.
[0010]
A signal processing circuit 32 that is electrically connected to the lead portions 30 and 31 of the coil body 3 is attached to the insulating substrate 2. The signal processing circuit 32 is a circuit that integrates an induced current generated in the coil body 3. The induced current is generated in the coil body 3 as a differential value of the current waveform flowing through the conductor to be measured, and the current waveform of the conductor to be measured is restored by the integration processing of the signal processing circuit 32.
[0011]
A plurality of first surface conductors 10 (conductors), which are conductive films, and a plurality of first back surface conductors 11 (conductors), which are conductive films, are respectively attached to the front surface 8 and the back surface 9 of the insulating substrate 2. ing. Further, the insulating substrate 2 is provided with a plurality of connection conductors 12 penetrating the insulating substrate 2. The winding advance coil portion 5 is formed by a plurality of first surface conductor portions 10 and a plurality of first back surface conductor portions 11 being electrically connected in series via respective connection conductor portions 12 to form a coil. .
[0012]
On the front surface 8 and the back surface 9 of the insulating substrate 2, a plurality of second surface conductor portions 15 (conductor portions), which are conductive films, and a plurality of second back surface conductor portions 16 (conductor portions), which are conductive films, respectively adhere. Have been. Each second surface conductor 15 is arranged between the first surface conductors 10, and each second back conductor 16 is arranged between the first back conductors 11. The insulating substrate 2 is provided with a plurality of connection conductors 17 penetrating the insulating substrate 2. The rewinding coil portion 6 is formed by electrically connecting a plurality of second surface conductor portions 15 and a plurality of second back surface conductor portions 16 in series through respective connection conductor portions 17 to form a coil. . In FIGS. 1 and 2, the conductive film formed on the back surface 9 is indicated by a broken line.
[0013]
Each of the first surface conductors 10 is arranged around the substrate opening 4 such that the inner end 10 a is arranged on the side closer to the substrate opening 4 and the outer end 10 b is arranged on the side farther from the substrate opening 4. Are arranged at a constant pitch substantially radially.
[0014]
Each of the first back conductors 11 is bent on the side away from the substrate opening 4 for connection to the connection conductor 12. Further, each of the first back surface conductors 11 has a substrate opening 4 such that the inner end 11 a is arranged on the side closer to the substrate opening 4 and the outer end 11 b is arranged on the side farther from the substrate opening 4. Are arranged at a constant pitch substantially radially around the.
[0015]
The second surface conductors 15 are arranged at a constant pitch around the substrate opening 4 on the surface 8 so as to be substantially radially alternated with the first surface conductors 10. Further, each second surface conductor 15 is arranged such that each inner end 15a and each outer end 15b are closer to the substrate opening 4 than each inner end 10a and each outer end 10b. ing.
[0016]
Each second back surface conductor 16 is bent on the side near the substrate opening 4 for connection to the connection conductor 17. The second back surface conductors 16 are arranged at a constant pitch around the substrate opening 4 on the back surface 9 so as to be substantially radially alternated with the first back surface conductor portions 11. Further, each second back surface conductor portion 16 is disposed such that each inner end portion 16a and each outer end portion 16b are closer to the substrate opening 4 than each inner end portion 11a and each outer end portion 11b. ing.
[0017]
As shown in FIG. 1, the substantially radial portions of each of the first surface conductor portion 10 and the first back surface conductor portion 11 are arranged to face each other, and the substantially radial portions of each of the second surface conductor portion 15 and the second back surface conductor portion 16 are arranged. The parts are arranged facing each other.
When viewed along the thickness direction of the insulating substrate 2, each of the first front surface conductor portions 10 and each of the first rear surface conductor portions 11 have their respective inner ends 10 a and their respective inner ends 11 a overlapping, and their respective outer ends. The portion 10b and each outer end 11b are arranged so as to overlap. When viewed along the thickness direction of the insulating substrate 2, each of the second front surface conductors 15 and each of the second back surface conductors 16 have their respective inner ends 15 a and their respective inner ends 16 a overlapping, The outer end 15b and each outer end 16b are arranged so as to overlap. Note that, in FIG. 1, substantially radial portions facing each other are shown side by side for easy understanding.
[0018]
The connecting conductor 12 electrically connects the plurality of first inner connecting conductors 13 electrically connecting the inner ends 10a and 11a overlapping each other in FIG. 1, and electrically connects the outer ends 10b and 11b overlapping each other in FIG. And a plurality of first outer connection conductors 14 connected to the first connection conductor 14.
[0019]
The connecting conductor 17 electrically connects the plurality of second inner connecting conductors 18 electrically connecting the inner ends 15a and the inner ends 16a to the outer ends 15b and the outer ends 16b. And a plurality of second outer connection conductor portions 19.
[0020]
FIG. 3 shows the insulating substrate 2, the advance coil portion 5, and the rewind coil portion 6 when viewed along the outer periphery of the substrate opening 4 in FIG. 1 (along the direction of the arrow 27 in FIG. 1). FIG. In the figure, a plurality of grooves 20 are formed on the front surface 8 and the back surface 9 of the insulating substrate 2. Each groove 20 extends substantially radially around the substrate opening 4 and is arranged along the circumferential direction of the substrate opening 4. The first surface conductor 10, the first back surface conductor 11, the second surface conductor 15, and the second back surface conductor 16 are attached to the inner surface of each groove 20.
The connection conductor 12 and the connection conductor 17 are copper conductive films formed on the inner surface of a through hole penetrating the insulating substrate 2 along the thickness direction of the insulating substrate 2, that is, metal through holes. .
[0021]
Further, the second inner connection conductor 18 is disposed closer to the substrate opening 4 than the first inner connection conductor 13, and the second outer connection conductor 19 is disposed closer to the substrate than the first outer connection conductor 14. It is arranged on the side closer to the opening 4 and on the side farther from the substrate opening 4 than the first inner connection conductor 13.
[0022]
That is, the winding coil section 5 and the rewind coil section 6 are, when viewed along the outer periphery of the substrate opening 4, a region surrounded by the conductive wire of the winding coil section 5, that is, the first surface conductor section 10, A region surrounded by the first back surface conductor portion 11, the first inner connection conductor portion 13, and the first outer connection conductor portion (hereinafter, referred to as a cross-sectional region of the winding-up coil portion 5) and a conductor of the rewinding coil portion 6 are surrounded. A region, that is, a region surrounded by the second front conductor portion 15, the second back conductor portion 16, the second inner connection conductor portion 18, and the second outer connection conductor portion 19 (hereinafter, referred to as a cross-sectional region of the rewinding coil portion 6) Are, for the most part, superimposed on one another. Furthermore, the area of the cross-sectional area of the winding coil section 5 and the area of the cross-sectional area of the rewind coil section 6 are substantially the same.
[0023]
FIG. 4 is a sectional view taken along the line IV-IV in FIG. In the figure, a partition 21 is formed between adjacent grooves 20. The partition 21 is formed by forming each groove 20 so that a part of the insulating substrate 2 is left. A flat surface 23 that is perpendicular to the thickness direction of the insulating substrate 2 is formed at the tip 22 of each partition 21. The width W1 of the flat surface 23 is smaller than the width W2 of the base 24 of the partition 21. That is, the width W1 of the plane 23 along the direction in which the grooves 20 are arranged is smaller than the width W2 of the base 24 along the direction in which the grooves 20 are arranged. Here, the open side of each groove 20 is expanded to form a tapered surface 25 at the distal end 22 of the partition 21, so that a flat surface having a width W1 smaller than the width W2 of the base 24 adjacent to the bottom of each groove 20. 23 are formed. No conductive film is attached to the plane 23. Therefore, the conductive films attached to the adjacent groove portions 20, that is, the first surface conductor portion 10 and the second surface conductor portion 15, and the first back surface conductor portion 11 and the second back surface conductor portion 16 are insulated from each other. .
[0024]
Next, the operation will be described.
When a current flows through the conductor to be measured, a magnetic flux passes through a cross-sectional area of the winding coil section 5 and a cross-sectional area of the rewind coil section 6, and an induced current is generated in the coil body 3. Since this induced current flows in the direction of the arrow shown in FIG. 2, the induced current generated at each location does not cancel each other out electrically. The induced current flowing through the conductor of the coil body 3 is integrated in the signal processing circuit 32 to calculate the waveform of the current flowing through the conductor to be measured.
[0025]
Next, a manufacturing method will be described.
FIG. 5 is a vertical cross-sectional view (cross-sectional view along the circumferential direction of the substrate opening 4) showing the shape of the insulating substrate 2 in FIG. First, an engineering plastic having a small thermal expansion is molded into a plate having a sectional shape as shown in FIG. 5 by a molding method such as a compression molding method or a casting method. That is, the plurality of partition portions 21 and the plurality of groove portions 20 each having the top portion 33 having a width smaller than the width W1 of the plane surface 23 are alternately formed on the front surface and the back surface of the engineering plastic plate.
[0026]
Then, after forming a plurality of through holes penetrating the engineering plastic plate between the ends of the groove portions 20 on the front surface and the back surface, a conductive film is attached to the entire surface of the plate and the inner surface of the through hole by dry plating or wet plating. Thereby, the conductive film can be attached to the entire surface of the plate and the inner surface of the through hole with a uniform thickness.
Then, polishing is performed on the front surface, the back surface, the outer surface, and the inner surface of the substrate opening 4 of the engineering plastic plate to remove the conductive film excluding the inner surface of the groove 20 and the inner surface of the through hole. At this time, on the front and back surfaces of the engineering plastic plate, the top 33 of the partition 21 is removed together with the conductive film to the polishing position 40. As a result, the conductive film is separated for each groove 20 to form each conductor. The coil body 3 is formed of the conductive film left on the inner surface of the groove 20 and the inner surface of the through hole, and the air-core coil 1 is completed.
[0027]
Since the width of the top 33 is smaller than the width W1 of the plane 23, the conductive film can be easily removed by polishing. Further, since the width W1 of the plane 23 formed in the partition 21 is smaller than the width W2 of the base 24, the amount of the conductive film to be removed can be reduced, and the conductive film can be removed in a short time. . Therefore, the air-core coil 1 can be manufactured in large quantities and at low cost.
[0028]
Further, the second inner connection conductor 18 is disposed closer to the substrate opening 4 than the first inner connection conductor 13, and the second outer connection conductor 19 is disposed closer to the substrate than the first outer connection conductor 14. Since it is arranged on the side closer to the opening 4 and farther from the substrate opening 4 than the first inner connection conductor 13, when viewed along the circumferential direction of the substrate opening 4, In the state where most of the respective cross-sectional areas of the winding-up coil section 5 and the rewinding coil section 6 overlap each other, the area of each cross-sectional area can be made substantially the same. From this, it is possible to further share the magnetic flux for generating the induced electromotive force in the leading coil portion 5 and the rewinding coil portion 6, and to make the magnitude of the induced electromotive force generated in each coil substantially equal. it can. Therefore, when the air core coil 1 is used for the current sensor, the measurement sensitivity can be improved and the measurement error can be reduced.
[0029]
Further, since the conducting wire of the coil body 3 can be formed almost completely symmetrically and uniformly with respect to the axis of the substrate opening 4, the measuring sensitivity can be further improved and the measuring error can be reduced. .
[0030]
In addition, since the insulating substrate 2 is formed by a molding method, there is no limitation on the size and shape of the insulating substrate 2 and the shape of the coil body 3 can be easily made into a desired shape.
[0031]
Embodiment 2 FIG.
FIG. 6 is a front view showing the configuration of the air-core coil according to Embodiment 2 of the present invention. FIG. 7 is a partially enlarged view showing the coil body 3 near the connection point 7 in FIG. In the figure, members or parts corresponding to the air-core coil 1 in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted here.
[0032]
The coil body 3 of the air-core coil 1 according to the second embodiment has a winding coil section 5 and a rewind coil section 6 provided on the insulating substrate 2 and connected in series with each other.
[0033]
As shown in FIG. 6, when viewed along the thickness direction of the insulating substrate 2, each first surface conductor portion 10 and each first back surface conductor portion 11 of the winding coil portion 5 form a saw-tooth pattern. Have been. Each of the second surface conductors 15 and each of the second back surface conductors 16 of the rewind coil unit 6 also form a saw-tooth pattern, and the saw-tooth pattern of the rewind coil unit 6 is Are arranged inside the sawtooth pattern. The sawtooth-shaped regions respectively surrounded by the lead wires of the winding coil unit 5 and the rewind coil unit 6 are the front region of the winding coil unit 5 and the front region of the rewind coil unit 6.
[0034]
That is, when viewed along the thickness direction of the insulating substrate 2, each inner end 15 a of the second front surface conductor 15 and the second back surface conductor 16 connected to each other via the second outer connection conductor 19. , 16a are spaced apart from each other along the direction in which the second surface conductors 15 and the second back surface conductors 16 are arranged. Further, the outer end portions 15b and 16b of the second surface conductor portion 15 and the second back surface conductor portion 16 connected to each other via the second inner connection conductor portion 18 also include the second surface conductor portion 15 and the second The rear conductors 16 are arranged apart from each other along the arrangement direction.
[0035]
Further, when viewed along the thickness direction of the insulating substrate 2, each inner end 10 a of the first surface conductor 10 and the first back surface conductor 11 connected to each other via the first outer connection conductor 14. , 11a are spaced apart from each other along the direction in which the first surface conductors 10 and the first back surface conductors 11 are arranged. Furthermore, the outer ends 10b and 11b of the first front conductor 10 and the first back conductor 11 connected to each other via the first inner connection conductor 13 are also connected to the first front conductor 10 and the first front conductors 11b. The rear conductors 11 are arranged apart from each other along the direction of arrangement.
[0036]
Furthermore, the inner ends 15a and 16a of each of the second front conductors 15 and the second back conductors 16 are higher than the inner ends 10a and 11a of each of the first front conductors 10 and the first back conductor 11. It is arranged on the side close to the substrate opening 4. Further, the outer ends 15b and 16b of each of the second front conductors 15 and the second back conductors 16 are larger than the outer ends 10b and 11b of each of the first front conductors 10 and the first back conductor 11. It is arranged on the side closer to the substrate opening 4 and further on the side farther from the substrate opening 4 than the inner ends 10 a and 11 a of the first surface conductors 10 and the first back surface conductors 11.
[0037]
Assuming that the first front surface conductor portion 10 and the first rear surface conductor portion 11 are vectors starting from the outer end portion 10b and the outer end portion 11b overlapping each other, the substrate opening 4 in the direction in which the vectors are synthesized. Each first front surface conductor portion 10 and each first back surface conductor portion 11 are provided so that a center point exists.
Similarly, assuming that the second front surface conductor portion 15 and the second rear surface conductor portion 16 are vectors starting from the outer end portion 15b and the outer end portion 16b which are overlapped with each other, the opening of the substrate in the synthesis direction of the vectors is considered. Each second surface conductor 15 and each second back surface conductor 16 are provided such that four center points exist.
Other configurations, manufacturing methods, and operations are the same as those in the first embodiment.
[0038]
Here, the induced current in the winding coil section 5 and the rewind coil section 6 is not only a magnetic field from the conductor to be measured, but also an external electromagnetic field passing through the front area of each of the winding coil section 5 and the rewind coil section 6. It is also generated by the world. The induced current due to the external electromagnetic field causes a measurement error of the current sensor. Therefore, in order to cancel out the induced currents due to the external electromagnetic field, it is preferable that the areas of the front regions of the winding coil portion 5 and the rewinding coil portion 6 are almost the same.
[0039]
Therefore, according to the air-core coil 1 according to the second embodiment, the same effect as that of the first embodiment can be obtained, and the area of the front area of the winding coil section 5 and the area of the front area of the rewind coil section 31 can be reduced. The area difference can be further reduced, and the measurement error due to the external electromagnetic field can be further reduced.
[0040]
In the first and second embodiments, the conductive film is removed by polishing. For example, a resist agent is applied to a portion where the conductive film is to be removed, and the conductive film is adhered to the entire surface of the insulating substrate 2. After the formation, the conductive film may be removed together with the resist agent, or the conductive film to be removed may be cut by a laser or the like.
[0041]
In the first and second embodiments, the insulating substrate 2 is not limited to being formed by the molding method, but may be formed by, for example, cutting.
[0042]
In Embodiments 1 and 2, a plurality of air-core coils 1 may be connected and used to further improve the measurement sensitivity of the current sensor. In this case, one signal processing circuit 32 is provided for a plurality of air core coils 1. Each air-core coil 1 is arranged with the substrate openings 4 aligned. To connect the coil bodies 3 to each other, one of the front surface 8 and the rear surface 9 is provided with a connection terminal from a lead portion 30 and the other is connected to a lead terminal. A connection terminal from the unit 31 is provided. Further, in order to facilitate connection between the connection terminals, a concave portion and a convex portion are respectively formed in the respective connection terminals, and the connection terminals are connected to each other by fitting the concave portions and the convex portions.
[0043]
In the first and second embodiments, each of the second inner connection conductors 18 and each of the first outer connection conductors 14 are conductive films attached to the inner surfaces of the through holes. As shown in FIG. 8 showing an example, even if it is a conductive film attached to the inner surfaces of a plurality of inner grooves 34 and outer grooves 35 formed on the inner surface of the substrate opening 4 and the outer surface of the insulating substrate 2 respectively. Good. Accordingly, the number of through holes formed in the insulating substrate 2 can be reduced, and each of the second inner connection conductors 18 and each of the first outer connection conductors 14 can be configured more easily. In this case, a tapered surface 37 is formed at the tip of the partition 36 between the inner grooves 34 and between the outer grooves 35 (the open side of the grooves 34 and 35).
Further, the second inner connection conductors 18 and the first outer connection conductors 14 may be formed by mixing the through holes, the inner groove 34, and the outer groove 35.
[0044]
Embodiment 3 FIG.
FIG. 9 is a partial perspective view showing a configuration of an air-core coil according to Embodiment 3 of the present invention. In the figure, a conductive shield 41, which is a conductive film, is attached to the outer surface of the insulating substrate 2 and the inner surface of the substrate opening 4 in the first or second embodiment. The conductive shield 41 is, for example, a conductive metal such as copper that is electrically grounded.
[0045]
The conductive shield 41 is formed on the outer surface of the insulating substrate 2 and the substrate during polishing after the conductive film is deposited on the entire surface of the insulating substrate 2 during the production of the air-core coil 1 in the first embodiment. It is formed by leaving the conductive film without polishing the inner surface of the opening 4.
[0046]
Here, the connection conductors 12 and 17 (see FIG. 2) of the coil main body 3 (see FIG. 1) provided on the insulating substrate 2 are conductive films attached to the inner surfaces of the through holes, and the conductive shield 41 is provided. Against short circuit. Other configurations are the same as in the first embodiment.
[0047]
As described above, since the conductive shield 41 is attached to the outer surface of the insulating substrate 2 and the inner surface of the substrate opening 4, generation of induced electromotive force due to an external electromagnetic field in the coil body 3 (see FIG. 1) is prevented. It can be suppressed by the conductive shield 41. Here, since the conductive shield 41 is grounded, it is not charged by the induced electromotive force generated by the external electromagnetic field.
[0048]
Embodiment 4 FIG.
FIG. 10 is a partial perspective view showing a configuration of an air-core coil according to Embodiment 3 of the present invention. In the figure, an insulating layer 42 of an insulating material is provided on the front surface, the back surface, the outer surface, and the inner surface of the substrate opening 4 in the insulating substrate 2 in the first or second embodiment. A conductive shield 43, which is a conductive film, is attached to the outer peripheral surface of the insulating layer 42. That is, the coil body 3 (see FIG. 1) and the insulating substrate 2 are covered (that is, surrounded) by the conductive shield 43 via the insulating layer 42. The conductive shield 43 is formed by electrically grounding a conductive metal such as copper. Other configurations are the same as in the first embodiment.
[0049]
Since the coil main body 3 (see FIG. 1) is thus surrounded by the conductive shield 43, the generation of induced electromotive force due to an external electromagnetic field in the coil main body 3 (see FIG. 1) is further suppressed by the conductive shield 41. can do.
[0050]
Note that the insulating layer 42 does not need to completely surround the insulating substrate 2 and may be, for example, in a grid shape, or in a state where the conductive shield 43 is kept out of contact with the internal coil body 3 (see FIG. 1). There may be a plurality of support protrusions.
[0051]
In the third and fourth embodiments, the conductive shields 41 and 43 are conductive films, but may be metal plates, for example.
When the air-core coil according to the second embodiment is used instead of the air-core coil according to the first embodiment, the measurement error due to the external electromagnetic field of the current sensor can be further reduced.
[0052]
【The invention's effect】
As is apparent from the above description, in the air-core coil according to the present invention, on at least one of the front surface and the rear surface, a plurality of grooves and a plurality of partitions extending substantially radially around the substrate opening are alternately arranged. The conductor portion is provided in each groove portion, and the width of the tip portion of the partition portion is smaller than the width of the base portion of the partition portion. With the method in which the conductive film is left as a conductor, the amount of the removed conductive film can be reduced, and the conductor can be formed in a short time.
[Brief description of the drawings]
FIG. 1 is a front view showing an air-core coil according to Embodiment 1 of the present invention.
FIG. 2 is a partially enlarged view showing a coil main body near a connection point in FIG. 1;
FIG. 3 is a layout diagram showing an insulating substrate, a winding coil unit, and a rewind coil unit when viewed along the outer periphery of the substrate opening in FIG. 1;
FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3;
FIG. 5 is a cross-sectional view taken along a circumferential direction of a substrate opening showing a shape of the insulating substrate in FIG. 4 in the process of being manufactured.
FIG. 6 is a front view showing a configuration of an air-core coil according to Embodiment 2 of the present invention.
FIG. 7 is a partially enlarged view showing a coil main body near a connection point in FIG. 6;
FIG. 8 is a partial perspective view showing an air-core coil according to a modification of the first embodiment of the present invention.
FIG. 9 is a partial perspective view showing a configuration of an air-core coil according to Embodiment 3 of the present invention.
FIG. 10 is a partial perspective view showing a configuration of an air-core coil according to Embodiment 4 of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 air core coil, 2 insulating substrate, 3 coil body, 4 substrate opening, 5 winding advance coil, 6 rewind coil, 8 front, 9 back, 10 first surface conductor (surface conductor), 11 1st back side conductor (back side conductor), 12, 17 connection conductor, 13 1st inside connection conductor (inside connection conductor), 14 1st outside connection conductor (outside connection conductor), 15 2nd surface Conductor (front surface conductor), 16 second back surface conductor (back surface conductor), 18 second inner connection conductor (inner connection conductor), 19 second outer connection conductor (outer connection conductor), 20 groove , 21, 36 partition, 22 tip, 24 base, 33 top, 34 inner groove, 35 outer groove.

Claims

An insulating substrate having a front surface, a back surface, and a substrate opening penetrating the front surface and the back surface and through which a conductor to be measured is passed;
A plurality of conductor portions provided substantially radially around the substrate opening on the front surface and the back surface, and connected to respective ends of the conductor portions on the front surface and the conductor portions on the back surface. A plurality of connection conductors, comprising a coil body configured in a coil shape by each of the conductors and each of the connection conductors,
On at least one of the front surface and the back surface, a plurality of grooves and a plurality of partitions extending substantially radially around the substrate opening are alternately arranged, and the conductor is provided in each of the grooves. ,
An air-core coil, wherein the width of the leading end of the partition is smaller than the width of the base of the partition.

After the conductive film is attached to the groove and the partition, the conductive film attached to the top of the partition is removed together with the top, whereby the conductive film is separated for each groove and the conductor is separated. The air-core coil according to claim 1, wherein the coil is formed.

A front surface, a back surface, and an insulating substrate having a substrate opening that penetrates the front surface and the back surface and through which the conductor to be measured is passed;
A conductor is wound around the substrate opening, a winding coil provided on the insulating substrate so as to surround the substrate opening, and a conductor is wound around the substrate opening. A winding coil portion provided on the insulating substrate so as to surround the substrate opening together with the winding coil portion, wherein the winding coil portion and the winding coil are driven by a current flowing through the conductor to be measured. A coil main body formed by connecting the winding coil section and the rewind coil section in series so that the induced electromotive force generated in the return coil section is electrically in the same direction,
The insulating substrate has a plurality of grooves provided on the front surface and the rear surface, respectively, and formed substantially radially around the substrate opening,
A plurality of surface conductor portions, wherein the winding advance coil portion and the rewind coil portion are formed in the grooves on the surface and have an inner end closer to the substrate opening and an outer end farther from the substrate opening; A plurality of back surface conductors formed in each of the grooves on the back surface and having an inner end on the near side and an outer end on the far side of the substrate opening, and one of the back surface conductors adjacent to each other; A plurality of inner connection conductors for electrically connecting an inner end of the back conductor and an inner end of the front conductor, and an outer end of the other back conductor and an outer end of the front conductor; Each having a plurality of outer connection conductors electrically connecting the
When viewed along the thickness direction of the insulating substrate, one of the winding coil portion and the rewind coil portion is such that each of the inner connection conductors is greater than the other of the inner connection conductors. The outer connection conductors are arranged closer to the substrate opening, and the outer connection conductors are closer to the substrate opening than the other outer connection conductors, and the substrate opening is closer to the other inner connection conductor. An air-core coil, which is disposed on a side far from the air-core coil.

The insulating substrate has a plurality of inner grooves formed on the inner surface of the substrate opening and extending from the front surface to the rear surface,
The air-core coil according to claim 3, wherein at least one of the inner connection conductors on the side closer to the substrate opening is provided in the inner groove.

A plurality of outer grooves provided on the outer surface and extending from the front surface to the back surface are formed on the insulating substrate,
5. The air-core coil according to claim 3, wherein at least one of the outer connection conductors farther from the substrate opening is provided in the outer groove.

The conductive shield is provided on the inner surface of the substrate opening and the outer surface of the insulating substrate insulated from the coil body. 2. The air-core coil according to item 1.

On the front surface, the rear surface, the inner surface of the substrate opening, and the outer surface of the insulating substrate, a conductive shield is provided via an insulating layer, and the conductive shield covers the insulating substrate. The air-core coil according to any one of claims 1 to 5, wherein: