JP3682052B2

JP3682052B2 - Magnetic detector

Info

Publication number: JP3682052B2
Application number: JP2003140209A
Authority: JP
Inventors: 昌広横谷; 出新條; 直洋三代; 直樹平岡
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2002-07-23
Filing date: 2003-05-19
Publication date: 2005-08-10
Anticipated expiration: 2023-05-19
Also published as: DE10333249B4; KR20040010258A; DE10333249A1; KR100636300B1; JP2004109113A

Description

【０００１】
【発明の属する技術分野】
この発明は、例えば周縁部に歯部が形成され周方向に回転する磁性移動体の回転位置を検出する磁気検出装置に関するものである。
【０００２】
【従来の技術】
図１３（ａ）は従来の磁気検出装置の斜視図、図１３（ｂ）は図１３（ａ）の磁気検出装置の部分平面図、図１４は従来の磁気検出装置の電気回路図、図１５はこの磁気検出装置の動作波形図である。
この磁気検出装置は、周縁部に歯部１ａが形成され周方向に回転軸４を中心に回転する磁性移動体１の平面上に磁性移動体１から離れて配設されているとともに、磁電変換素子である磁気抵抗セグメント２ａおよび固定抵抗１２ｂによるブリッジ回路、並びに固定抵抗１２ｃおよび固定抵抗１２ｄによるブリッジ回路を有する処理回路部２０と、磁気抵抗セグメント２ａに磁界を印加させるとともに磁性移動体１に対して磁性移動体１の回転軸線方向に磁界を印加させる磁石３とを備えている。また、処理回路部２０は、磁気抵抗セグメント２ａの抵抗値変化により電圧変化された信号を増幅する差動増幅回路１３、比較回路１４及び出力回路１５を内蔵している。
【０００３】
上記構成の磁気検出装置では、回転軸４が回転することで磁性移動体１も同期して回転し、磁気抵抗セグメント２ａに印加される磁石３からの磁界が変化する。その結果、図１５に示すように、磁性移動体１の歯部１ａが磁気抵抗セグメント２ａに対向したときと、溝部１ｂに対向したときとでは、磁気抵抗セグメント２ａの抵抗値が変化し、また差動増幅回路１３からの出力も変化する。そして、最終的には処理回路部２０の出力端子１６からは、差動増幅回路出力が波形整形され、磁性移動体１の歯部１ａ及び溝部１ｂに対応して"１"または"０"の最終出力信号が得られる。
【０００４】
【発明が解決しようとする課題】
ところで、図１６（ａ）、（ｂ）に示すように、隣接した歯部１ａ間の間隔、および歯部１ａ自体の周方向の幅が小さく、また磁性移動体１の周面と磁気抵抗セグメント２ａとの対向方向の間隔（以下、ＧＡＰと呼ぶ。）が大きいときには、図１７に示すように処理回路部２０の出力端子１６からは、"１"または"０"の最終出力信号が得られない場合が生じるという問題点があった。
【０００５】
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あって、隣接した歯部間の間隔、および歯部自体の周方向の幅が小さく、またＧＡＰが大きいときでも磁性移動体の回転位置を検出できる磁気検出装置を得ることを目的とする。
【０００６】
【課題を解決するための手段】
この発明に係る磁気検出装置は、縁部に凸部が形成されているとともに移動する磁性移動体の平面上に磁性移動体から離れて配設されており、第１の磁電変換素子および第２の磁電変換素子によるブリッジ回路を有する処理回路部と、前記第１の磁電変換素子および前記第２の磁電変換素子に磁界を印加させるとともに前記磁性移動体の移動方向の面に対して垂直方向に磁界を印加させる磁石とを備え、前記第２の磁電変換素子は、前記垂直方向に沿って視たときに前記磁性移動体と対向する線上における前記磁石のほぼ中心線上に配置され、前記第１の磁電変換素子は、前記第２の磁電変換素子と前記磁性移動体の変位側でもって対向して配置され、前記第１の磁電変換素子および前記第２の磁電変換素子の出力から差動出力を得るようになっている。
【０００７】
【発明の実施の形態】
以下、この発明の各実施の形態について説明するが、従来のものと同一、または相当部材、部位については同一符号を付して説明する。
実施の形態１．
図１（ａ）はこの発明の実施の形態１の磁気検出装置の斜視図、図１（ｂ）は図１（ａ）の磁気検出装置の部分平面図、図１（ｃ）は図１（ａ）の磁気抵抗セグメントのパターン図である。
この磁気検出装置は、周縁部に凸部である歯部１ａが形成され周方向に回転軸４を中心に回転する磁性移動体１の平面上に磁性移動体１から離れて配設されているとともに、磁電変換素子である第１の磁気抵抗セグメント２ａおよび第２の磁気抵抗セグメント２ｂからなるブリッジ回路を有する処理回路部２と、磁気抵抗セグメント２ａ、２ｂに磁界を印加させるとともに磁性移動体１に対して磁性移動体１の回転軸線方向に磁界を印加させる磁石３と、処理回路部２と磁石３との間に設けられ磁石３からの磁束が分散するのを防止する磁性体ガイド５とを備えている。この磁性体ガイド５は周方向に間隔おいて対向した一対の突極部５ａ、５ｂを有している。また、処理回路部２は、磁気抵抗セグメント２ａ、２ｂの抵抗値変化が電圧に変化された信号を増幅する差動増幅回路１３、比較回路１４及び出力回路１５を内蔵している。
このブリッジ回路では、図１４に示した従来のものと比較して固定抵抗１２ｂの代わりに第２の磁気抵抗セグメント２ｂが組み入れられている点が異なる。
第１の磁気抵抗セグメント２ａは、第２の突極部５ｂ側に配置されている。第２の磁気抵抗セグメント２ｂは、回転軸線方向に沿って視たときに磁石３の前記周方向の幅寸法のほぼ中心線上で、かつ一対の突極部５ａ、５ｂ間のほぼ中心線上に配置されている。
【０００８】
上記構成の磁気検出装置では、回転軸４が回転することで磁性移動体１も同期して回転し、磁気抵抗セグメント２ａ、２ｂに印加される磁石３からの磁界が変化する。その結果、図２に示すように、磁性移動体１の歯部１ａが磁気抵抗セグメント２ａに対向したときと、溝部１ｂに対向したときとでは、磁気抵抗セグメント２ａの抵抗値が変化し、差動増幅回路１３からの出力も変化する。そして、最終的には処理回路部２の出力端子１６からは、差動増幅回路出力が波形整形され、磁性移動体１の歯部１ａ及び溝部１ｂに対応して"１"または"０"の最終出力信号が得られる。
この実施の形態では、図２から分かるように、隣接した歯部１ａ間の間隔、および歯部１ａ自体の周方向の幅が小さく、またＧＡＰが大きいときでも、処理回路部２の出力端子１６からは、"１"または"０"の最終出力信号が得られ、磁気検出装置は、磁性移動体１に対する位置検出精度が向上する。
【０００９】
実施の形態２．
図３（ａ）はこの発明の実施の形態２の磁気検出装置の斜視図、図３（ｂ）は図３（ａ）の磁気検出装置の部分平面図、図３（ｃ）は図３（ａ）の磁気抵抗セグメントのパターン図である。
この実施の形態では、実施の形態１のものと比較して、処理回路部２は、さらに第３の磁電変換素子２ｃおよび第４の磁電変換素子２ｄによるブリッジ回路を有している。
第２の磁気抵抗セグメント２ｂおよび第３の磁気抵抗セグメント２ｃは、回転軸線方向に沿って視たときに磁石３の前記周方向の幅寸法のほぼ中心線上で、かつ一対の突極部５ａ、５ｂ間のほぼ中心線上に配置されている。第１の磁気抵抗セグメント２ａは、第２の突極部５ｂ側に配置され、第４の磁気抵抗セグメント２ｄは、第１の突極部５ａ側に配置されている。
また、第１の磁気抵抗セグメント２ａおよび第２の磁気抵抗セグメント２ｂの中点出力と、第３の磁気抵抗セグメント２ｃおよび第４の磁気抵抗セグメント２ｄの中点出力とから差動出力を得るようになっている。
【００１０】
図４はこの実施の形態の磁気検出装置の動作波形図であり、磁性移動体１の形状に対応して磁気抵抗セグメント２ａ、２ｂ、２ｃ、２ｄの抵抗値が変化し、第１の磁気抵抗セグメント２ａおよび第２の磁気抵抗セグメント２ｂの中点出力と、第３の磁気抵抗セグメント２ｃおよび第４の磁気抵抗セグメント２ｄの中点出力との差動増幅出力が得られ、この差動増幅出力が波形整形され、磁性移動体１の形状に対応した最終出力信号"１"ｏｒ"０"を得ることができる。
【００１１】
図５は実施の形態１および実施の形態２の磁気検出装置のそれぞれの動作波形を比較した図である。この図から、それぞれの検出位置ズレの最大箇所同士を比較したときに、その検出位置ズレの大きさは、実施の形態１よりも実施の形態２の方が小さいことが分かる。
【００１２】
実施の形態３．
図６（ａ）はこの発明の実施の形態３の磁気検出装置の斜視図、図６（ｂ）は図６（ａ）の磁気検出装置の部分平面図、図６（ｃ）は図６（ａ）の磁気抵抗セグメントのパターン図である。
この実施の形態では、第２の磁気抵抗セグメント２ｂおよび第３の磁気抵抗セグメント２ｃに対する歯部１ａの先端面との対向距離と、第１の磁気抵抗セグメント２ａおよび第４の磁気抵抗セグメント２ｄに対する歯部１ａの先端面との対向距離がそれぞれ異なる。
他の構成は、実施の形態２と同様である。
【００１３】
図７は、それぞれの対向距離の差をＭとし、Ｍの値が−０．１ｍｍ、０ｍｍ、＋０．１ｍｍそれぞれのときに、ＧＡＰの大きいときと小さいときとに場合分けした動作波形図である。
この図から、Ｍ＝−０．１ｍｍの場合が０ｍｍ、＋０．１ｍｍの場合と比較してＧＡＰの大小における検出ズレが小さいことが分かる。
このように、上記Ｍの値を調整することで、ＧＡＰを大きくすることで生じる検出性能の低下を抑制することができる。
【００１４】
実施の形態４．
この実施の形態では、一対の突極部５ａ、５ｂ間の中心線上にある、第２の磁気抵抗セグメント２ｂおよび第３の磁気抵抗セグメント２ｃと、突極部５ａ、５ｂの近傍にある第１の磁気抵抗セグメント２ａおよび第４の磁気抵抗セグメント２ｄとの間の距離Ｎ（図６（ｃ）参照）を調整することで、磁性移動体１の回転位置の検出精度を高める例である。
図８は、このセグメントピッチＮと、差動増幅出力ＭＩＮ振幅との関係を示す。ここで、差動増幅出力ＭＩＮ振幅とは、差動増幅出力電圧と比較電圧との差が最小であるときの幅をいう。このＭＩＮ振幅の値が小さければそれだけ位置検出精度が悪くなり、図８の例では、セグメントピッチＮが１．５ｍｍ〜３ｍｍの範囲のときには、磁性移動体１の回転位置を検出することができる差動増幅出力を得ることができ、高い検出性能が確保される。
【００１５】
実施の形態５．
この実施の形態では、対向した突極部５ａ、５ｂ間の対向距離を、セグメントピッチＮとの関係で調整することで、磁性移動体１の回転位置の検出精度を高める例である。
図９は、一例として、セグメントピッチＮが２．５ｍｍの場合における、突極部５ａと突極部５ｂとの間の距離、即ち突極部ピッチと、差動増幅出力ＭＩＮ振幅との関係を示す。図９の例では、突極部ピッチが５ｍｍ以上（磁気抵抗セグメントピッチＮの２倍以上）のときに、磁性移動体１の回転位置を検出することができる差動増幅出力を得ることができる。
【００１６】
実施の形態６．
この実施の形態は、磁電変換素子として巨大磁気抵抗素子（以下ＧＭＲとする）を用いた例である。
ＧＭＲ素子は、数オングストロームから数十オングストロームの厚さの磁性層と非磁性層とを交互に積層させた積層体、いわゆる人工格子膜であり、（Ｆｅ／Ｃｒ）ｎ、（パーマロイ／Ｃｕ／Ｃｏ／Ｃｕ）ｎ、（Ｃｏ／Ｃｕ）ｎが知られており、これは磁気抵抗セグメント（以下、ＭＲ素子と呼ぶ。）と比較して格段に大きなＭＲ効果（ＭＲ変化率）を有するとともに、隣り合った磁性層の磁化の向きの相対角度にのみ依存するので、外部磁界の向きが電流に対してどのような角度差をもっていても同じ抵抗値変化が得られる面内感磁の素子である（ｎは積層数）。但し、磁気抵抗パターンの幅を狭くすることで異方性をつけることができる素子でもある。
また、印加磁界の変化による抵抗値変化にヒステリシスが存在するとともに、温度特性、特に温度係数が大きいという特徴を備えた素子である（図１０にＧＭＲ素子のＭＲループ特性を示す）。
このように、磁電変換素子にＧＭＲ素子を用いることにより、ＳＮ比が向上し、ノイズ耐量を上昇させることができる。
【００１７】
実施の形態７．
図１１はこの実施の形態の磁気検出装置の電気回路図、図１２はその磁気検出装置の動作波形図である。
この実施の形態では、処理回路部２は、実施の形態２のものと比較して、さらに第１の磁気抵抗セグメント２ａおよび第２の磁気抵抗セグメント２ｂの中点出力と、第３の磁気抵抗セグメント２ｃおよび第４の磁気抵抗セグメント２ｄの中点出力とから得たそれぞれの出力から磁性移動体１の回転方向を検知する差動フリップフロップ回路２０を有している。
また、処理回路部２は、第１および第２の磁気抵抗セグメント２ａ、２ｂの中性点での抵抗値変化が電圧変化に変化された信号を増幅する第１の差動増幅回路１３Ａ、第１の比較回路１４Ａおよび出力回路１５を内蔵している。また、処理回路部２は、第３および第４の磁気抵抗セグメント２ｃ、２ｄの中性点での抵抗値変化が電圧変化に変化された信号を増幅する第２の差動増幅回路１３Ｂ、第２の比較回路１４Ｂおよび差動フリップフロップ回路（Ｄ−ＦＦ回路）２０を内蔵している。
【００１８】
この実施の形態では、磁性移動体１の形状に対応して第１の磁気抵抗セグメント２ａおよび第２の磁気抵抗セグメント２ｂの抵抗値が変化し、第１の差動増幅回路１３Ａからの出力も変化する。そして、その増幅回路出力が波形整形され、磁性移動体１の歯部１ａおよび溝部１ｂに対応して"１"ｏｒ"０"の最終出力信号が得られる。
また、同様に、磁性移動体１の形状に対応して第３の磁気抵抗セグメント２ｃおよび第４の磁気抵抗セグメント２ｄの抵抗値が変化し、第２の増幅回路１３Ｂからの出力も変化する。そして、その増幅回路出力が波形整形され、磁性移動体１の歯部１ａおよび溝部１ｂに対応して"１"ｏｒ"０"の最終出力信号が得られる。これらの両出力信号は、Ｄ−ＦＦ回路２０に入力され、磁性移動体１が正転時にはＤ−ＦＦ回路２０出力がＬｏｗ、逆転時にはＤ−ＦＦ回路２０出力がＨｉｇｈとなり、磁性移動体１の逆転を検知することができる。
【００１９】
なお、上記実施の形態では、磁性移動体１は、周縁部に凸部である歯部１ａが形成された円板形状であって、周方向に回転するようになっているが、勿論このものに限定されるものではなく、例えば縁部に凸部を有する往復直線運動可能な磁性移動体であってもよい。
この場合には、磁石からの磁界を磁性移動体の直線方向の移動により形成される面に対して垂直方向に磁界を印加されており、第１の磁電変換素子は前記垂直方向に沿って視たときに磁性移動体と対向する線上で磁石のほぼ中心線上に配置されている。
【００２０】
【発明の効果】
以上説明したように、この発明に係る磁気検出装置によれば、縁部に凸部が形成されているとともに移動する磁性移動体の平面上に磁性移動体から離れて配設されており、第１の磁電変換素子および第２の磁電変換素子によるブリッジ回路を有する処理回路部と、前記第１の磁電変換素子および前記第２の磁電変換素子に磁界を印加させるとともに前記磁性移動体の移動方向の面に対して垂直方向に磁界を印加させる磁石とを備え、前記第２の磁電変換素子は、前記垂直方向に沿って視たときに前記磁性移動体と対向する線上における前記磁石のほぼ中心線上に配置され、前記第１の磁電変換素子は、前記第２の磁電変換素子と前記磁性移動体の変位側でもって対向して配置され、前記第１の磁電変換素子および前記第２の磁電変換素子の出力から差動出力を得るようになっているので、隣接した凸部間の間隔、および凸部自体の移動方向の幅が小さく、また磁性移動体との間のＧＡＰが大きいときでも、良好な検出性能を得ることができる。
【図面の簡単な説明】
【図１】図１（ａ）はこの発明の実施の形態１の磁気検出装置の斜視図、図１（ｂ）は図１（ａ）の磁気検出装置の部分平面図、図１（ｃ）は図１（ａ）の磁気抵抗セグメントのパターン図である。
【図２】図１の磁気検出装置の動作波形図である。
【図３】図３（ａ）はこの発明の実施の形態２の磁気検出装置の斜視図、図３（ｂ）は図３（ａ）の磁気検出装置の部分平面図、図３（ｃ）は図３（ａ）の磁気抵抗セグメントのパターン図である。
【図４】図３の磁気検出装置の動作波形図である。
【図５】実施の形態１の磁気検出装置の動作波形と実施の形態２の磁気検出装置の動作波形とを重ね合わせた図である。
【図６】図６（ａ）はこの発明の実施の形態３の磁気検出装置の斜視図、図６（ｂ）は図６（ａ）の磁気検出装置の部分平面図、図６（ｃ）は図６（ａ）の磁気抵抗セグメントのパターン図である。
【図７】実施の形態３の磁気検出装置の動作波形図である。
【図８】この発明の実施の形態４の磁気検出装置におけるセグメントピッチＮと差動増幅出力ＭＩＮ振幅との関係を示す図である。
【図９】この発明の実施の形態５の磁気検出装置における突極部ピッチと差動増幅出力ＭＩＮ振幅との関係を示す図である。
【図１０】この発明の実施の形態６の磁気検出装置におけるＧＭＲ素子のＭＲループ特性図である。
【図１１】実施の形態７の磁気検出装置の電気回路図である。
【図１２】実施の形態７の磁気検出装置の動作波形図である。
【図１３】図１３（ａ）は従来の磁気検出装置の斜視図、図１３（ｂ）は図１３（ａ）の磁気検出装置の部分平面図である。
【図１４】図１３の磁気検出装置の電気回路図である。
【図１５】図１３の磁気検出装置の動作波形図である。
【図１６】図１６（ａ）は従来の他の例の磁気検出装置の斜視図、図１６（ｂ）は図１６（ａ）の磁気検出装置の部分平面図である。
【図１７】図１６の磁気検出装置の動作波形図である。
【符号の説明】
１磁性移動体、１ａ歯部（凸部）、２処理回路部、２ａ第１の磁気抵抗セグメント、２ｂ第２の磁気抵抗セグメント、２ｃ第３の磁気抵抗セグメント、２ｄ第４の磁気抵抗セグメント、３磁石、４回転軸、５磁性体ガイド、５ａ第１の突極部、５ｂ第２の突極部、２０差動フリップフロップ回路。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic detection device that detects a rotational position of a magnetic moving body that rotates, for example, in a circumferential direction with teeth formed on a peripheral edge.
[0002]
[Prior art]
13A is a perspective view of a conventional magnetic detection device, FIG. 13B is a partial plan view of the magnetic detection device of FIG. 13A, FIG. 14 is an electric circuit diagram of the conventional magnetic detection device, and FIG. These are operation | movement waveform diagrams of this magnetic detection apparatus.
This magnetic detection device is disposed away from the magnetic moving body 1 on the plane of the magnetic moving body 1 that is formed with a tooth portion 1a at the peripheral portion and rotates around the rotation shaft 4 in the circumferential direction, and is also magnetoelectrically converted. A magnetic circuit is applied to the magnetoresistive segment 2a and a magnetic circuit 1 is applied to the processing circuit unit 20 having a bridge circuit including the magnetoresistive segment 2a and the fixed resistor 12b, and a bridge circuit including the fixed resistor 12c and the fixed resistor 12d. And a magnet 3 for applying a magnetic field in the direction of the rotation axis of the magnetic moving body 1. In addition, the processing circuit unit 20 includes a differential amplifier circuit 13, a comparison circuit 14, and an output circuit 15 that amplify a signal whose voltage has been changed by a change in the resistance value of the magnetoresistive segment 2a.
[0003]
In the magnetic detection device having the above-described configuration, when the rotating shaft 4 rotates, the magnetic moving body 1 also rotates in synchronization with each other, and the magnetic field from the magnet 3 applied to the magnetoresistive segment 2a changes. As a result, as shown in FIG. 15, the resistance value of the magnetoresistive segment 2a changes between when the tooth portion 1a of the magnetic moving body 1 faces the magnetoresistive segment 2a and when it faces the groove portion 1b. The output from the differential amplifier circuit 13 also changes. Finally, the output of the differential amplifier circuit is waveform-shaped from the output terminal 16 of the processing circuit unit 20, and is “1” or “0” corresponding to the tooth portion 1 a and the groove portion 1 b of the magnetic moving body 1. A final output signal is obtained.
[0004]
[Problems to be solved by the invention]
By the way, as shown in FIGS. 16 (a) and 16 (b), the interval between adjacent teeth 1a and the width in the circumferential direction of the teeth 1a itself are small, and the peripheral surface of the magnetic mobile body 1 and the magnetoresistive segment When the distance in the opposite direction to 2a (hereinafter referred to as GAP) is large, a final output signal of “1” or “0” is obtained from the output terminal 16 of the processing circuit unit 20 as shown in FIG. There was a problem that there was no case.
[0005]
An object of the present invention is to solve the above-described problems. The gap between adjacent teeth and the circumferential width of the teeth themselves are small, and even when GAP is large, the magnetic An object of the present invention is to obtain a magnetic detection device capable of detecting the rotational position of a moving body.
[0006]
[Means for Solving the Problems]
The magnetic detection device according to the present invention has a convex portion formed at the edge portion and is disposed on the plane of the moving magnetic moving body away from the magnetic moving body, and includes the first magnetoelectric conversion element and the second magnetoelectric conversion element. A processing circuit unit having a bridge circuit by the magnetoelectric conversion element, a magnetic field applied to the first magnetoelectric conversion element and the second magnetoelectric conversion element, and a direction perpendicular to the plane of movement of the magnetic moving body A magnet for applying a magnetic field, and the second magnetoelectric transducer is disposed substantially on the center line of the magnet on a line facing the magnetic moving body when viewed along the vertical direction . The first magnetoelectric conversion element is disposed opposite to the second magnetoelectric conversion element on the displacement side of the magnetic moving body, and differentially outputs from the outputs of the first magnetoelectric conversion element and the second magnetoelectric conversion element. To get the output You have me.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Each embodiment of the present invention will be described below, but the same reference numerals are used to describe the same or corresponding members and parts as those in the prior art.
Embodiment 1 FIG.
1A is a perspective view of a magnetic detection device according to Embodiment 1 of the present invention, FIG. 1B is a partial plan view of the magnetic detection device of FIG. 1A, and FIG. It is a pattern figure of the magnetoresistive segment of a).
This magnetic detection device is disposed away from the magnetic moving body 1 on the plane of the magnetic moving body 1 that is formed around the rotating shaft 4 in the circumferential direction with the tooth portion 1a that is a convex portion formed at the peripheral edge. In addition, a magnetic field is applied to the processing circuit unit 2 having a bridge circuit composed of the first magnetoresistive segment 2a and the second magnetoresistive segment 2b, which are magnetoelectric transducers, and the magnetic moving body 1 is applied to the magnetoresistive segments 2a and 2b. A magnet 3 for applying a magnetic field in the direction of the rotation axis of the magnetic moving body 1, and a magnetic guide 5 provided between the processing circuit unit 2 and the magnet 3 to prevent the magnetic flux from the magnet 3 from dispersing. It has. The magnetic body guide 5 has a pair of salient pole portions 5a and 5b opposed to each other in the circumferential direction. Further, the processing circuit unit 2 includes a differential amplifier circuit 13, a comparison circuit 14, and an output circuit 15 that amplify a signal in which the resistance value change of the magnetoresistive segments 2a and 2b is changed to a voltage.
This bridge circuit is different from the conventional circuit shown in FIG. 14 in that a second magnetoresistive segment 2b is incorporated instead of the fixed resistor 12b.
The first magnetoresistive segment 2a is disposed on the second salient pole portion 5b side. The second magnetoresistive segment 2b is disposed substantially on the center line of the circumferential width dimension of the magnet 3 and substantially on the center line between the pair of salient pole portions 5a and 5b when viewed along the rotational axis direction. Has been.
[0008]
In the magnetic detection device having the above-described configuration, when the rotating shaft 4 rotates, the magnetic moving body 1 also rotates synchronously, and the magnetic field from the magnet 3 applied to the magnetoresistive segments 2a and 2b changes. As a result, as shown in FIG. 2, the resistance value of the magnetoresistive segment 2a changes between when the tooth portion 1a of the magnetic moving body 1 faces the magnetoresistive segment 2a and when the tooth portion 1a opposes the groove 1b. The output from the dynamic amplification circuit 13 also changes. Finally, the output of the differential amplifier circuit is waveform-shaped from the output terminal 16 of the processing circuit unit 2, and is “1” or “0” corresponding to the tooth portion 1 a and the groove portion 1 b of the magnetic moving body 1. A final output signal is obtained.
In this embodiment, as can be seen from FIG. 2, the output terminal 16 of the processing circuit unit 2 is provided even when the interval between adjacent teeth 1a and the circumferential width of the teeth 1a itself are small and GAP is large. , A final output signal of “1” or “0” is obtained, and the magnetic detection device improves the position detection accuracy with respect to the magnetic moving body 1.
[0009]
Embodiment 2. FIG.
3A is a perspective view of the magnetic detection device according to Embodiment 2 of the present invention, FIG. 3B is a partial plan view of the magnetic detection device of FIG. 3A, and FIG. 3C is FIG. It is a pattern figure of the magnetoresistive segment of a).
In this embodiment, as compared with the first embodiment, the processing circuit unit 2 further includes a bridge circuit including a third magnetoelectric conversion element 2c and a fourth magnetoelectric conversion element 2d.
The second magnetoresistive segment 2b and the third magnetoresistive segment 2c are substantially on the center line of the circumferential width dimension of the magnet 3 when viewed along the rotational axis direction, and a pair of salient pole portions 5a, It is arrange | positioned on the approximate centerline between 5b. The 1st magnetoresistive segment 2a is arrange | positioned at the 2nd salient pole part 5b side, and the 4th magnetoresistive segment 2d is arrange | positioned at the 1st salient pole part 5a side.
Further, a differential output is obtained from the midpoint output of the first magnetoresistive segment 2a and the second magnetoresistive segment 2b and the midpoint output of the third magnetoresistive segment 2c and the fourth magnetoresistive segment 2d. It has become.
[0010]
FIG. 4 is an operation waveform diagram of the magnetic detection device of this embodiment. The resistance values of the magnetoresistive segments 2a, 2b, 2c, and 2d change corresponding to the shape of the magnetic moving body 1, and the first magnetoresistance A differential amplification output between the midpoint output of the segment 2a and the second magnetoresistance segment 2b and the midpoint output of the third magnetoresistance segment 2c and the fourth magnetoresistance segment 2d is obtained, and this differential amplification output The waveform is shaped, and the final output signal “1” or “0” corresponding to the shape of the magnetic moving body 1 can be obtained.
[0011]
FIG. 5 is a diagram comparing operation waveforms of the magnetic detection devices of the first embodiment and the second embodiment. From this figure, it can be seen that when the maximum positions of the respective detection position deviations are compared, the magnitude of the detection position deviation is smaller in the second embodiment than in the first embodiment.
[0012]
Embodiment 3 FIG.
6A is a perspective view of the magnetic detection device according to Embodiment 3 of the present invention, FIG. 6B is a partial plan view of the magnetic detection device of FIG. 6A, and FIG. 6C is FIG. It is a pattern figure of the magnetoresistive segment of a).
In this embodiment, the distance between the second magnetoresistive segment 2b and the third magnetoresistive segment 2c and the tip surface of the tooth portion 1a, and the first magnetoresistive segment 2a and the fourth magnetoresistive segment 2d. The facing distance from the tip surface of the tooth portion 1a is different.
Other configurations are the same as those in the second embodiment.
[0013]
FIG. 7 is an operation waveform diagram in which the difference between the facing distances is M, and when the value of M is −0.1 mm, 0 mm, and +0.1 mm, the GAP is large and small. .
From this figure, it can be seen that the detection deviation in the magnitude of the GAP is smaller in the case of M = −0.1 mm than in the case of 0 mm and +0.1 mm.
Thus, by adjusting the value of M, it is possible to suppress a decrease in detection performance caused by increasing GAP.
[0014]
Embodiment 4 FIG.
In this embodiment, the second magnetoresistive segment 2b and the third magnetoresistive segment 2c, which are on the center line between the pair of salient pole portions 5a and 5b, and the first magnet in the vicinity of the salient pole portions 5a and 5b. This is an example in which the detection accuracy of the rotational position of the magnetic movable body 1 is increased by adjusting the distance N (see FIG. 6C) between the magnetoresistive segment 2a and the fourth magnetoresistive segment 2d.
FIG. 8 shows the relationship between the segment pitch N and the differential amplification output MIN amplitude. Here, the differential amplification output MIN amplitude refers to the width when the difference between the differential amplification output voltage and the comparison voltage is minimum. If the value of the MIN amplitude is small, the position detection accuracy is deteriorated accordingly. In the example of FIG. 8, when the segment pitch N is in the range of 1.5 mm to 3 mm, the rotational position of the magnetic moving body 1 can be detected. Dynamic amplification output can be obtained, and high detection performance is ensured.
[0015]
Embodiment 5 FIG.
In this embodiment, by adjusting the facing distance between the salient pole portions 5a and 5b facing each other in relation to the segment pitch N, the detection accuracy of the rotational position of the magnetic mobile body 1 is increased.
FIG. 9 shows an example of the relationship between the salient pole part 5a and the salient pole part 5b, that is, the salient pole part pitch and the differential amplification output MIN amplitude when the segment pitch N is 2.5 mm. Show. In the example of FIG. 9, when the salient pole portion pitch is 5 mm or more (more than twice the magnetoresistive segment pitch N), a differential amplification output capable of detecting the rotational position of the magnetic moving body 1 can be obtained. .
[0016]
Embodiment 6 FIG.
This embodiment is an example in which a giant magnetoresistive element (hereinafter referred to as GMR) is used as a magnetoelectric conversion element.
The GMR element is a so-called artificial lattice film in which a magnetic layer and a nonmagnetic layer having a thickness of several angstroms to several tens of angstroms are alternately laminated, and is (Fe / Cr) n, (Permalloy / Cu / Co). / Cu) n and (Co / Cu) n are known, which have a much larger MR effect (MR change rate) than a magnetoresistive segment (hereinafter referred to as an MR element) and are adjacent to each other. Since it depends only on the relative angle of the magnetization direction of the combined magnetic layer, it is an in-plane magnetosensitive element that can obtain the same change in resistance regardless of the angle of the external magnetic field with respect to the current ( n is the number of layers). However, it is also an element that can have anisotropy by narrowing the width of the magnetoresistive pattern.
Further, the element has a characteristic that a resistance value change due to a change of an applied magnetic field has hysteresis and a temperature characteristic, particularly a temperature coefficient is large (FIG. 10 shows an MR loop characteristic of a GMR element).
Thus, by using a GMR element for the magnetoelectric conversion element, the SN ratio can be improved and the noise tolerance can be increased.
[0017]
Embodiment 7 FIG.
FIG. 11 is an electric circuit diagram of the magnetic detection device of this embodiment, and FIG. 12 is an operation waveform diagram of the magnetic detection device.
In this embodiment, the processing circuit unit 2 further includes a midpoint output of the first magnetoresistive segment 2a and the second magnetoresistive segment 2b and a third magnetoresistive as compared with the second embodiment. A differential flip-flop circuit 20 is provided for detecting the rotational direction of the magnetic mobile body 1 from the respective outputs obtained from the midpoint output of the segment 2c and the fourth magnetoresistive segment 2d.
In addition, the processing circuit unit 2 includes a first differential amplifier circuit 13A that amplifies a signal in which the resistance change at the neutral point of the first and second magnetoresistive segments 2a and 2b is changed to a voltage change. 1 comparator circuit 14A and output circuit 15 are incorporated. In addition, the processing circuit unit 2 includes a second differential amplifier circuit 13B that amplifies a signal whose resistance value change at the neutral point of the third and fourth magnetoresistive segments 2c and 2d is changed to a voltage change. 2 comparator circuit 14B and differential flip-flop circuit (D-FF circuit) 20 are incorporated.
[0018]
In this embodiment, the resistance values of the first magnetoresistive segment 2a and the second magnetoresistive segment 2b change corresponding to the shape of the magnetic moving body 1, and the output from the first differential amplifier circuit 13A is also changed. Change. Then, the output of the amplifier circuit is waveform-shaped, and a final output signal of “1” or “0” corresponding to the tooth portion 1a and groove portion 1b of the magnetic moving body 1 is obtained.
Similarly, the resistance values of the third magnetoresistive segment 2c and the fourth magnetoresistive segment 2d change corresponding to the shape of the magnetic moving body 1, and the output from the second amplifier circuit 13B also changes. Then, the output of the amplifier circuit is waveform-shaped, and a final output signal of “1” or “0” corresponding to the tooth portion 1a and groove portion 1b of the magnetic moving body 1 is obtained. Both of these output signals are input to the D-FF circuit 20, and when the magnetic moving body 1 is rotating forward, the output of the D-FF circuit 20 is Low, and when the magnetic moving body 1 is rotating backward, the output of the D-FF circuit 20 is High. Reversal can be detected.
[0019]
In the above embodiment, the magnetic moving body 1 has a disk shape in which the teeth 1a which are convex portions are formed on the peripheral edge, and is rotated in the circumferential direction. It is not limited to this, For example, the magnetic moving body which can carry out the reciprocating linear motion which has a convex part in an edge part may be sufficient.
In this case, the magnetic field from the magnet is applied in a direction perpendicular to the surface formed by the linear movement of the magnetic moving body, and the first magnetoelectric transducer is viewed along the vertical direction. Is disposed on the center line of the magnet on the line facing the magnetic moving body.
[0020]
【The invention's effect】
As described above, according to the magnetic detection device of the present invention, the convex portion is formed at the edge portion, and the magnetic detection device is disposed on the plane of the moving magnetic moving body away from the magnetic moving body. A processing circuit unit having a bridge circuit including one magnetoelectric conversion element and a second magnetoelectric conversion element; and applying a magnetic field to the first magnetoelectric conversion element and the second magnetoelectric conversion element and moving the magnetic moving body And a magnet for applying a magnetic field in a direction perpendicular to the surface of the magnet, wherein the second magnetoelectric transducer is substantially at the center of the magnet on a line facing the magnetic moving body when viewed along the vertical direction. Arranged on a line, and the first magnetoelectric conversion element is arranged opposite to the second magnetoelectric conversion element on the displacement side of the magnetic moving body, and the first magnetoelectric conversion element and the second magnetoelectric conversion element Magnetoelectric transducer Since the differential output is obtained from, the distance between adjacent convex parts, the width of the convex part itself in the moving direction is small, and even when the GAP between the magnetic movable body is large, good detection is possible. Performance can be obtained.
[Brief description of the drawings]
FIG. 1 (a) is a perspective view of a magnetic detection device according to Embodiment 1 of the present invention, FIG. 1 (b) is a partial plan view of the magnetic detection device of FIG. 1 (a), and FIG. FIG. 2 is a pattern diagram of the magnetoresistive segment of FIG.
2 is an operation waveform diagram of the magnetic detection device of FIG. 1. FIG.
3 (a) is a perspective view of the magnetic detection device according to Embodiment 2 of the present invention, FIG. 3 (b) is a partial plan view of the magnetic detection device of FIG. 3 (a), and FIG. 3 (c). FIG. 4 is a pattern diagram of the magnetoresistive segment of FIG.
4 is an operation waveform diagram of the magnetic detection device of FIG. 3;
FIG. 5 is a diagram in which the operation waveform of the magnetic detection device of the first embodiment and the operation waveform of the magnetic detection device of the second embodiment are superimposed.
6 (a) is a perspective view of a magnetic detection device according to Embodiment 3 of the present invention, FIG. 6 (b) is a partial plan view of the magnetic detection device of FIG. 6 (a), and FIG. 6 (c). FIG. 7 is a pattern diagram of the magnetoresistive segment of FIG.
FIG. 7 is an operation waveform diagram of the magnetic detection apparatus according to the third embodiment.
FIG. 8 is a diagram showing a relationship between a segment pitch N and a differential amplification output MIN amplitude in the magnetic detection device according to the fourth embodiment of the present invention.
FIG. 9 is a diagram showing a relationship between salient pole pitches and differential amplification output MIN amplitudes in the magnetic detection device according to the fifth embodiment of the present invention.
FIG. 10 is an MR loop characteristic diagram of the GMR element in the magnetic detection apparatus according to the sixth embodiment of the present invention.
FIG. 11 is an electric circuit diagram of the magnetic detection device according to the seventh embodiment.
FIG. 12 is an operation waveform diagram of the magnetic detection apparatus according to the seventh embodiment.
13 (a) is a perspective view of a conventional magnetic detection device, and FIG. 13 (b) is a partial plan view of the magnetic detection device of FIG. 13 (a).
14 is an electric circuit diagram of the magnetic detection device of FIG. 13;
FIG. 15 is an operation waveform diagram of the magnetic detection device of FIG. 13;
16 (a) is a perspective view of another conventional magnetic detection device, and FIG. 16 (b) is a partial plan view of the magnetic detection device of FIG. 16 (a).
17 is an operation waveform diagram of the magnetic detection device of FIG. 16;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Magnetic moving body, 1a Tooth part (convex part), 2 Processing circuit part, 2a 1st magnetoresistive segment, 2b 2nd magnetoresistive segment, 2c 3rd magnetoresistive segment, 2d 4th magnetoresistive segment, 3 Magnet, 4 Rotating shaft, 5 Magnetic guide, 5a First salient pole part, 5b Second salient pole part, 20 Differential flip-flop circuit.

Claims

A convex portion is formed at the edge and the magnetic moving body is disposed on the plane of the moving magnetic moving body and is separated from the magnetic moving body, and has a bridge circuit including the first magnetoelectric conversion element and the second magnetoelectric conversion element. A processing circuit section;
A magnet for applying a magnetic field to the first magnetoelectric conversion element and the second magnetoelectric conversion element and applying a magnetic field in a direction perpendicular to the plane of movement of the magnetic moving body,
The second magnetoelectric conversion element is disposed on a substantially center line of the magnet on a line facing the magnetic moving body when viewed along the vertical direction ,
The first magnetoelectric conversion element is disposed opposite to the second magnetoelectric conversion element on the displacement side of the magnetic moving body,
A magnetic detection device configured to obtain a differential output from outputs of the first magnetoelectric conversion element and the second magnetoelectric conversion element.

The magnetic detection device according to claim 1, wherein the magnetic moving body has a disc shape in which a tooth portion is formed at a peripheral portion, and rotates in a circumferential direction.

A magnetic material guide having a pair of salient poles facing each other in the circumferential direction is provided between the processing circuit unit and the magnet, and the second magnetoelectric conversion element is a pair of the salient pole parts 3. The magnetic detection device according to claim 2, wherein the first magnetoelectric transducer is disposed on one of the salient pole portions side while being disposed substantially on a center line therebetween.

The processing circuit unit further includes a bridge circuit including a third magnetoelectric conversion element and a fourth magnetoelectric conversion element, and the third magnetoelectric conversion element is disposed on a substantially center line between the pair of salient pole parts. The fourth magnetoelectric conversion element is disposed on the other salient pole part side, the midpoint output of the first magnetoelectric conversion element and the second magnetoelectric conversion element, the third magnetoelectric conversion element, and the The magnetic detection device according to claim 3, wherein a differential output is obtained from a midpoint output of the fourth magnetoelectric transducer.

The facing distance between the second magnetoelectric conversion element and the third magnetoelectric conversion element with respect to the tip surface of the tooth portion is the tip surface of the tooth portion with respect to the first magnetoelectric conversion element and the fourth magnetoelectric conversion element. The magnetic detection device according to claim 4, wherein the magnetic detection device is adjusted according to a relationship with a facing distance.

The distance in the circumferential direction of each of the first magnetoelectric conversion element and the fourth magnetoelectric conversion element is adjusted in relation to a distance from the second magnetoelectric conversion element and the third magnetoelectric conversion element. Item 6. The magnetic detection device according to item 4 or 5.

The facing distance between the salient pole portions facing each other is the distance in the circumferential direction between the first magnetoelectric conversion element and the second magnetoelectric conversion element, and the third magnetoelectric conversion element and the fourth magnetoelectric conversion. The magnetic detection device according to claim 4, wherein the magnetic detection device is adjusted based on a relationship with a distance in a circumferential direction from an element.

The processing circuit unit is obtained from the midpoint output of the first magnetoelectric conversion element and the second magnetoelectric conversion element and the midpoint output of the third magnetoelectric conversion element and the fourth magnetoelectric conversion element. The magnetic detection device according to claim 4, further comprising a differential flip-flop circuit that detects a rotation direction of the magnetic moving body from each output.

The magnetic detection device according to claim 1, wherein the magnetoelectric conversion element is a giant magnetoresistive element (GMR element).