JP4230249B2 - Throttle opening detector - Google Patents

Description

【数３】

【００２６】
上記Ｈｘ，Ｈｙは、いずれも回転角θの関数でありいずれも角度情報を持つので、ＨｘあるいはＨｙのいずれかの信号を検出して角度信号とすることは可能であり、従来の装置においてもこの原理を利用したものが多い。
しかしながら数２および数３の両式とも磁場の強さＢが係数として存在しているためこのＢの値が変化するとＨｘ，Ｈｙが変化して誤差を生じる。
【００２７】
たとえば磁石１を取り付けている回転軸１０にガタが生じて磁電変換素子との相対距離が変化したり、不安定になると距離の逆数に比例して磁場強さが変化するので出力が変動し誤差の原因となる。また一般的に磁石の磁場強さには温度係数があるため温度変化によっても磁場の強さＢが変化し誤差を生じる。
【００２８】
そこで本第１実施形態における角度算出装置３は、２つのマグネト・インピーダンス素子２１、２２の出力の比を演算し、それにもとづいて角度を求める。すなわち２つのマグネト・インピーダンス素子２１、２２の出力の比Ｈｙ/ Ｈｘは数４のごとくになり、Ｈｙ/ Ｈｘの分子および分母の前記磁場強さＢの項が消去されるので前述の距離変化あるいは温度変化などによる磁場強さの変動の影響をなくすことができる。さらに前記Ｈｙ／Ｈｘはマグネト・インピーダンス素子２１、２２の出力であるから、たとえば温度変化によって２つのマグネト・インピーダンス素子２１、２２に感度変化があっても互いの温度係数が同じであればこれも消去されるので高精度な計測が可能である。
【数４】

なお上記数４に見られるように角度θとＨｙ／Ｈｘとの関係は一般的に非線形である。
【００２９】
つぎにαを９０度に設定すると、上記数４は cos（９０−θ）／ cosθ＝tan θであるから、前記数１のごとくarctan（Ｈｙ／Ｈｘ）の演算をすることによりＨｙ／Ｈｘにもとづいてθを直線的に求めることができる。
【００３０】
したがって２つのマグネト・インピーダンス素子２１、２２で検出したｘ、ｙ各軸方向の磁気信号から演算によって直線関係がよくさらに安定で高精度な角度計測を可能にすることができる。
【００３１】
次に前記磁電変換素子としてのマグネト・インピーダンス磁気検出器２０は、アモルファスワイヤからなるため１２０℃の高温動作が可能であり、また２つのマグネト- インピーダンス素子の信号を交互に切換えて時系列で信号処理をするため、電子回路を１つ用意すればよく、さらなる低コスト化の効果を奏する。
【００３２】
また前記角度算出装置３は、前記信号処理回路２３の出力信号Ｈｙ、Ｈｘからarctan（Ｈｙ／Ｈｘ）の演算を行い角度信号を出力する。
【００３３】
さらに以上述べたごとく本第１実施形態におけるスロットル開度検知装置は、従来のように磁電変換素子に印加する磁場が変化しないように磁気センサと磁石との距離の安定化を図る機構部品を設けたり、磁場強さあるいはセンサ感度の安定化をはかるための電磁的な補償などの対策を施す必要がなくなるので、小型で安価な角度センサを実現できるものである。
【００３４】
（第２実施形態）
本第２実施形態のスロットル開度検知装置は、前記図１の構成に対応しており、詳細は図３に示される。回転軸１０に取り付けられた磁石１は、前記図１と同じであるため図示を省略する。
【００３５】
マグネト・インピーダンス磁気検出器２０は、２つのマグネト・インピーダンス素子と１つの共通の信号処理回路からなる。ｘ軸およびｙ軸の２つのマグネト・インピーダンス素子２１，２２は、互いに角度αが９０度で各軸方向成分の信号を検出するべく前記回転磁場内に配設されている。
【００３６】
マグネト・インピーダンス素子２１，２２は、アモルファスワイヤに検出コイルが巻回されてなるものでこのアモルファスワイヤにパルス電流を通電すると周囲の磁場の軸方向成分に対応する電圧が検出コイルに瞬間的に誘起される。この検出コイルに誘起された電圧を信号処理することで磁場信号を得ることができる。
【００３７】
信号処理回路２３は、前記２つのマグネト・インピーダンス素子２１、２２の信号を処理するためのもので、パルスジェネレータ２３１とサンプルホールド回路２３２からなる。
【００３８】
パルスジェネレータ２３１は、繰返し周波数が２ＭＨｚでパルス幅が数十ｎｓ（ナノ秒）でかつ所定の位相差で同期する２つのパルス列を発生し、端子Ｐ１、Ｐ２の組とＰ３、Ｐ４の組からそれぞれ５μｓ（マイクロ秒）の周期で切換えて交互に出力する。また、出力端子Ｐ５は、このパルス列を５μｓごとに交互に切換えるときの同期信号が出力されるが、これは後段の角度算出装置３に出力される。
【００３９】
前記パルスジェネレータ２３１の出力端子Ｐ1 およびＰ３は、ｘ軸、ｙ軸２つのマグネト・インピーダンス素子２１，２２のアモルファスワイヤに接続されているので、５μｓごとに交互に２ＭＨｚのパルス列の電流が印加される。パルスが印加されるとマグネト・インピーダンス素子２１および２２の各検出コイルには周囲の磁場に対応する電圧が瞬間的に誘起される。
【００４０】
アナログスイッチＳ１、Ｓ２の制御端子に前記パルスジェネレータ２３１の出力端子Ｐ２、Ｐ４のパルスが印加されるが、前記のごとく端子Ｐ１とＰ２のパルスおよびＰ３とＰ４のパルスはそれぞれ同期しているので、パルスが印加されるとごく短期間スイッチが" 閉" になり前記マグネト・インピーダンス素子２１，２２の検出コイルに瞬間的に誘起した磁場に対応する電圧がコンデンサＣにホールドされる。
【００４１】
前述のごとくマグネト・インピーダンス素子２１、２２に印加されるパルス列は、２ＭＨｚであるので、磁場の計測は２ＭＨｚの繰り返し頻度で間欠的に実行されるが、アナログスイッチＳ1 、Ｓ２とコンデンサＣおよび増幅器Ａがサンプルホールド回路２３２を形成しているので、この出力端子Ｐ６の信号はほぼ連続的な波形である。
【００４２】
しかしながら前述のようにパルスジェネレータ２３１は、５μｓの周期でパルス列をＰ１，Ｐ２の組とＰ３，Ｐ４の組と交互に出力するので、このマグネト・インピーダンス磁気検出器２の出力端子Ｐ６の信号は前記マグネト・インピーダンス素子２１および２２が検出した磁気信号すなわち前記ｘおよびｙ方向成分の磁場信号を時系列的に交互に出力する。
【００４３】
図４におけるａは前記図１における磁石１が一定の回転角速度で回転するときのｘ、ｙ各軸のマグネト・インピーダンス素子に印加される磁場を表す。したがって横軸は時間でありかつ角度である。ｂはこのときのマグネト・インピーダンス磁気検出器２の出力端子Ｐ６の信号波形を表す。同図ｂにおいて、Ｘ、Ｙの記号は前記のごとくｘ、ｙ各軸に対応するマグネト・インピーダンス素子２１および２２の出力が５μs の周期で交互に切換えられているところを表している。このｂは理解の便のためにｘ, ｙの切換えの時間幅を角度変化する早さに対して誇張して広く描いているが、実際には機械的な角度変化に対して十分短かな時間であるため実用上角度情報が途切れるようなことにはならない。
【００４４】
前記角度演算装置３は、主としてＡ／Ｄコンバータ３１とマイクロコンピュータ３２からなり前記回転磁場のｘ方向とｙ方向成分の比にもとづいてソフトウエアにより回転角度を演算し、出力端子Ｐ７から出力する。
【００４５】
前記Ｐ６の磁場信号は、Ａ／Ｄコンバータ３１に接続されており、時系列的に交互に切換えられたｘおよびｙ方向成分の磁場信号は順次デジタル変換される。このときＡ／Ｄ変換された信号をｘ軸のデータとｙ軸のデータとに弁別するため同期信号として前記パルスジェネレータ２３１の端子Ｐ５の切換え信号をマイクロコンピュータ３２に入力している。
【００４６】
すなわちパルスジェネレータ２３１の端子Ｐ５から出力される前記５μｓの切換え信号がロジックレベルの" １" のときはｘ方向の磁場信号、そして" ０" のときはy 方向の磁場信号としてコンピュータ３２はｘ、ｙ軸のデータを整列する。
【００４７】
角度算出演算は、前記Ａ／Ｄ変換されたデータをもとにソフトウエアで行うがここでは前記数１に基づくθ＝arctan（Ｈｙ／Ｈｘ）の演算により、角度と出力信号との関係を直線化する。
【００４８】
図５は、角度θと演算された結果の例であり、角度変化に対して出力が線形であることを表している。なお本第２実施形態においては、角度変化が−９０度から＋９０度の１８０度の領域に対して負から正へ信号が直線的に変化し、それ以上の角度変化については出力はその繰り返しとなる。
【００４９】
以上本第２実施形態により磁石１の回転による回転磁場を２つのマグネト・インピーダンス素子２１、２２によって検出し、その信号の比から角度演算することにより、磁場変動、磁電変換素子の感度変化の影響を受けない安定で高精度の角度検出を可能にするとともに、かかる角度センサを実現するものである。
【００５０】
また本第２実施形態においては、一方のマグネト・インピーダンス素子がパルス通電され動作している時には他方のマグネト・インピーダンス素子はパルス通電されていないため動作していないことから、互いに他方のマグネト・インピーダンス素子のパルス通電に伴う動作による電磁的影響を受けることはないため、高精度の回転数検知を可能にするとともに、信号処理回路における同時信号処理をすることはないため、信号処理における干渉も無く、消費電力の低減を可能にするものである。
【００５１】
（第３実施形態）
第３実施形態のスロットル開度検知装置は、前記マグネト・インピーダンス磁気検出器２として２つのマグネト・インピーダンス素子２１、２２と時系列で切換えて信号処理する１つの信号処理回路２３をＩＣ化して超小型素子として構成し、回転磁場内に容易に配設できるようにしたものである。
【００５２】
すなわち図６に示されるようにマグネト・インピーダンス磁気検出器２００は、周囲に検出コイルを２０２，２０４を巻回した長さ２ｍｍ、直径３０μｍのアモルファスワイヤ２０１，２０３をマグネト・インピーダンス素子とし、それらを互いに直交的に配置しかつその近傍にＩＣ化した信号処理回路２０５を同一基板に配設したものである。またこの信号処理回路２０５は、上述の実施形態と同じく切換えで２つのマグネト・インピーダンス素子２１、２２の信号を処理するものである。
【００５３】
また本第３実施形態のスロットル開度検知装置は、２つのマグネト・インピーダンス素子２１、２２と１つの信号処理回路２３とを基板上に一体に形成され、ＩＣ化したものであるので、２つのセンサの特性を揃えることが出来るため、精度の高い測定を可能にするとともに、センサを小さくし、高感度化を可能にし、処理回路もシンプルにし、全体として小型化して、重量および消費電力を低減するという効果を奏する。
【００５４】
さらに配線用の電極２０６を備えた２ｍｍ×３ｍｍのＩＣパッケージ２０７に収納することで装置全体を小型化するとともに前記回転磁場内に容易に取り付けることができるようにしたものである。
【００５５】
さらに前記マグネト・インピーダンス素子の材料としてアモルファスワイヤを用いることで通常の磁電変換素子では厳しい１２０℃以上の温度領域においても計測可能にし、温度環境の厳しいエンジンのスロットルポジションセンサとして安定かつ高精度の測定を可能にし、小型化さらに低価格化を実現するものである。
【００５６】
【実施例】
以下上述の実施形態のスロットル開度検知装置において、用いることが出来る磁気検出器の実施例につき、図面を用いて説明する。
【００５７】
（実施例）
本実施例の磁気検出器は、図７に示されるように自動車分野における適用を考慮して、小型化するとともに高感度化したもので、以下図７ないし図９を用いて説明する。
【００５８】
前記磁気検出器２を構成する２つのマグネト・インピーダンス素子２１、２２の基板１００の大きさは、幅０．５ｍｍ、高さ０．５ｍｍとし、長手方向の長さを３ｍｍとし、感磁体２１０、２２０は、ＣｏＦｅＳｉＢ系合金を使った直径３０μｍのアモルファスワイヤである。 電磁コイル２１１、２２１は、 前記基板１００の長手方向に形成した溝１００Ｇの溝面１００Ｓに形成されたコイルの片側２１１Ａ、２２１Ａと、溝１００Ｇの溝上面１１２に形成された残り片側のコイル２１１Ｂ、２２１Ｂの２層構造により形成したものである。
【００５９】
前記溝面１１１および溝上面１１２に形成されるコイルの片側２１１Ａ、２２１Ａおよび残り片側のコイル２１１Ｂ、２２１Ｂは、図７および図８に示されるように電極配線基板１００の長手方向に形成された溝１００Ｇの溝上面１１２よりある程度広い範囲にコイルを構成する導電性の磁性金属薄膜を蒸着により形成し、形成された金属薄膜が螺旋状に残るように間隙部を構成する導電性金属薄膜部を選択エッチング手法により除去することにより、コイルの全体の長手方向の長さを１．５ｍｍまたは２ｍｍの長さに亘り形成される。なお図８において、図７のＡ−Ａ′断面にかかわらず、理解の便のために溝１００Ｇの全面の４面にロの字状にコイルが形成されている状態を示した。
【００６０】
電磁コイル２１１、２２１の円相当内径（高さと幅で形成される溝断面積と同一面積となる円の直径）は、２００μｍまたは１００μｍ以下であるのが望ましいので、６６μｍに一例として設定した。 電磁コイル２１１、２２１の１ターン当たりの（単位長さ当たり）の捲線間隔は１００μｍ／巻以下であるのが望ましいので、一例として５０μｍ／巻に設定されている。
【００６１】
素子基板の長さとして３ｍｍを採用して前記２つのマグネト・インピーダンス素子２１、２２のアモルファスワイヤ２１０、２２０および電磁コイル２１１、２２１が、図８に示されるように一つの素子基板としての電極配線基板１００上にそれぞれ一体に形成され、前記磁気検出器２１、２２の両端に配設した電極を介して接続された前記電子回路２３（図示せず）も一つの電極配線基板１００上に形成され、かかる電子回路２３からのセンサ出力を横軸が外部磁場と縦軸が出力電圧を示す図９に示す。
【００６２】
本実施例の磁気検出器は、自動車分野における適用を考慮して、小型化、薄型化、小容積化（幅０．５ｍｍ、高さ０．５ｍｍとし、長手方向の長さを３ｍｍ）を実現しながら、図９から明らかなように４０ガウス（Ｇ）で０．２Ｖのフルスケールまでリニアなが出力が得られ、リニアな測定および高感度な測定を実現するものである。
【００６３】
また本実施例の磁気検出器は、前記２つのマグネト・インピーダンス素子２１、２２のアモルファスワイヤ２１０、２２０および検知コイルとしての電磁コイル２１１、２２１が、全体基板上に一体に形成され、前記磁気検出器２１、２２の両端に配設した電極を介して接続された前記信号処理回路としての電子回路２３も同一全体基板上に形成され、同一のパッケージ内に配設され、前記２つの検知コイルとしての電磁コイルと電子回路とが、同一の基板上にマウントされているので、２つのセンサの特性を揃えることが出来るため、精度の高い測定を可能にするとともに、センサを小さくし、高感度化を可能にし、処理回路もシンプルにし、全体として小型化して、重量および消費電力を低減するという効果を奏する。
【００６４】
また本実施例の磁気検出器は、マグネト・インピーダンス素子としてアモルファスワイヤを採用したので、アモルファスワイヤの本来の性質上、１２０℃の温度環境でも安定な動作が可能なため、自動車における１２０℃の温度環境でも安定な動作が可能であり、スロットル開度の検出に適するという効果を奏するものである。
【００６５】
さらに本実施例の磁気検出器は、マグネト・インピーダンス素子をより高感度な磁気センサとするために、検出コイルとしての電磁コイル２１１、２２１の円相当内径の半径を２００μｍまたは１００μｍ以下にするのが望ましい、本実施例においては一例として６６μｍに設定し、極めて小さくしてアモルファスワイヤと検出コイルとの電磁結合を大きくすることに対して有効であるとともに、センサの薄型化および小容量化にとっても有効である。
【００６６】
また本実施例の磁気検出器は、前記２つのマグネト・インピーダンス素子および信号処理回路を１つの基板にマウント（装荷）することにより、小型かつ取り扱いを容易にすることができ、さらにマグネト・インピーダンス素子が高感度のため回転体とのギャップを１ｍｍ以上に大きくしても安定な磁気計測ができるので自動車に取り付ける際に精密な組付け作業を必要としないので生産コストを抑制するという非常に大きな効果を奏する。
【００６７】
さらに本実施例においては、2 つのマグネト・インピーダンス素子を所定の精度で管理された自動機で製作するとともに、２つのマグネト・インピーダンス素子をそれぞれ駆動するＩＣ回路からなるパルスジェネレータの２つのドライバー回路の駆動特性およびそれぞれに対応するサンプルホールド回路の２つのアナログスイッチのスイッチ特性を同一とするため、それぞれ近接した場所に回路を形成するようにマスク設計を行い、２つのマグネト・インピーダンス素子の特性を互いに等しくなるようにしたので、2 つのマグネト・インピーダンス素子の特性を互いに等しくすることが出来るものである。
【００６８】
本実施例においては、基板１００の大きさは、幅０．５ｍｍ、高さ０．５ｍｍとし、長手方向の長さを３ｍｍとし、アモルファスワイヤの長さは３ｍｍ以下であることから、上述した図９から明らかなように４０ガウスで０．２Ｖのフルスケールまでリニヤーな出力が得られるため、従来ヒステリシス特性や非直線特性を無くすためにアモルファスワイヤにもう一つのコイルを設けてこれにフィードバック電流を流したり、バイアス電流を流したりするフィードバック技術の必要性を解消するものである。これにより常時直流電流を流すことが不要となり低消費電力化が可能となった。またバイアスコイルを省略できマグネト・インピーダンス素子をシンプル化するものである。
【００６９】
上述の実施形態は、説明のために例示したもので、本発明としてはそれらに限定されるものでは無く、特許請求の範囲、発明の詳細な説明および図面の記載から当業者が認識することができる本発明の技術的思想に反しない限り、変更および付加が可能である。
【００７０】
上述の実施形態において説明したように、本発明は、回転軸１０に取り付けられたスロットル開度検出用磁石１の回転に伴う２つの磁場信号の比に基づいて角度計測を行うことで磁場強さの変化、磁電変換素子の感度変化に対して安定かつ高温度領域でも計測でき、また小型，安価なスロットル開度センサを実現するものであって、スロットル開度検出用磁石以外の用途の磁石の回転角を前記マグネト・インピーダンス素子によって検出すれば、スロットル開度以外の回転要素の回転角を検出する用途への適用が可能である。
【図面の簡単な説明】
【図１】本発明の第１実施形態のスロットル開度検知装置を示すブロック図である。
【図２】本第１実施形態のスロットル開度検知装置における計測原理を説明するための説明図である。
【図３】本発明の第２実施形態のスロットル開度検知装置を示す詳細ブロック図である。
【図４】本第２実施形態のスロットル開度検知装置における出力波形を示す線図である。
【図５】本第２実施形態の操舵角検知装置における角度変化に対する出力の変化の関係を示す線図である。
【図６】本発明の第３実施形態におけるマグネト・インピーダンス磁気検出器のパッケージを示す平面図である。
【図７】本発明の実施例における磁気検出器を示す平面図である。
【図８】本実施例における磁気検出器を示す図７中Ａ−Ａ′線に沿う横断面図である。
【図９】本実施例における磁気検出器の外部磁場と出力電圧の関係を示す線図である。図である。
【符号の説明】
１ スロットル開度検出用磁石
２ 磁気センサ
２０ マグネト・インピーダンス磁気検出器
２１、２２ マグネト・インピーダンス素子
２３ 信号処理回路
３ 演算回路[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic sensor for detecting a magnetic field by a rotating throttle opening detection magnet, a signal processing circuit for signal processing of a change in the detected magnetic field, and a throttle opening based on an output signal output from the signal processing circuit. The present invention relates to a throttle opening degree detection device provided with an arithmetic circuit for calculating.
[0002]
[Prior art]
In a conventional magnetic type throttle angle sensor, a magnet and a magnetoelectric conversion element are arranged so as to be relatively rotatable, and a vector component of this rotating magnetic field is generated by a Hall element or a magnetoresistive element that is the magnetoelectric conversion element existing in the magnetic field. It was something to detect.
[0003]
The conventional throttle angle sensor outputs a rotation angle by obtaining the magnitude of the signal of the sensitivity axial direction component by a magnetoelectric conversion element such as a Hall element arranged in a magnetic field by a magnet. When the play is mechanically caused by a change in clearance such as the distance between the magnet and the magnetoelectric transducer changes, the strength of the magnetic field applied to the magnetoelectric transducer changes, which causes an error in the detected angle output signal. was there.
[0004]
Therefore, the conventional first throttle angle sensor has a magnet so that the strength of the magnetic field received by the magnetoelectric transducer does not change even if the distance between the Hall element that generates a detection signal and the magnet changes according to the direction of the magnetic field. In addition, the mechanism part for holding the magnet is devised, and the contrivance on the magnetic circuit and the mechanism is added (see, for example, Patent Document 1).
[0005]
In addition, the conventional second throttle angle sensor makes the magnetic flux uniform and reduces errors even if the relative position of the Hall element as a magnetoelectric conversion element that outputs an electric signal corresponding to the direction of the magnetic field and the magnet changes. As described above, a concave groove is provided in the magnet to add a device on the magnetic circuit (see, for example, Patent Document 2).
[0006]
Further, the conventional third throttle angle sensor has a hole-type sensor that prevents the gap between the magnet and the Hall element from changing even when a force is applied to the Hall element as a magnetoelectric conversion element that generates a detection signal according to the direction of the magnetic field. A fixing member, which is a complicated mechanism component having an element positioning portion, is prepared, and a mechanism is added (for example, see Patent Document 3).
[0007]
[Patent Document 1]
JP-A-6-42907 (page 3-4, FIGS. 1 to 3)
Japanese Patent Laid-Open No. 10-132506 (page 3-4, FIG. 1)
Japanese Patent Laid-Open No. 10-62113 (page 2-5, FIGS. 1 and 2)
[0008]
[Problems to be solved by the invention]
All of the above conventional throttle angle sensors detect the tilt angle between the magnetic field and the element from the magnetic force detected by the Hall element, but in order to stabilize this measurement, a device on the magnetic circuit or mechanism is added. Therefore, since the structure is delicate and complicated, there is a problem that the assembly becomes large in size and requires high-cost and high-precision assembly work.
[0009]
Further, the conventional throttle angle sensor has a problem that an error is mixed due to a change in strength of a magnetic field generated by a magnet due to a temperature change or a change in sensitivity of a magnetoelectric conversion element.
[0010]
In recent years, there has been a strong demand for higher accuracy in devices and equipment, particularly in the automobile field, and there is a growing need for higher accuracy, smaller size, lighter weight, and energy saving for the throttle angle sensor.
[0011]
Therefore, the present inventor has developed a magnetic sensor that detects a magnetic field by a rotating throttle opening detection magnet, a signal processing circuit that performs signal processing on the detected change in the magnetic field, and a throttle based on an output signal that is output from the signal processing circuit. In a throttle opening detection device having an arithmetic circuit for calculating an opening, outputs from two magneto-impedance elements constituting the magnetic sensor arranged in different directions constitute the signal processing circuit 1 In each of the signal processing circuits, the signal obtained by alternately switching by the switching means is processed, and in the arithmetic circuit, the two magneto-impedance elements are detected and alternately output from the signal processing circuit. A book that detects the throttle opening based on the output ratio of two magneto-impedance elements As a result of further research and development, focusing on the technical idea of Ming, no magnetic circuit and mechanism ingenuity to prevent the occurrence of errors due to the change in the distance between the magnet and the magnetoelectric transducer is required. The present invention has achieved the object of proposing an angle sensor that has high stability and is small in size, low power consumption, and high temperature resistance without being affected by changes in strength and sensitivity changes of the magnetoelectric transducer.
[0012]
[Means for Solving the Problems]
The throttle opening detection device of the present invention (the first invention according to claim 1),
A magnetic sensor that detects a magnetic field by a rotating throttle opening detection magnet, a signal processing circuit that performs signal processing on the detected change in the magnetic field, and an operation that calculates the throttle opening based on an output signal output from the signal processing circuit In the throttle opening detection device equipped with a circuit,
The magnetic sensor is composed of two magneto-impedance elements arranged in different directions,
The two magneto-impedance elements are configured to receive a pulse current of two pulse trains that have a repetition frequency and a pulse width and are synchronized with a predetermined phase difference. Addition Two amorphous wires that are wound around the two amorphous wires Addition Consisting of two detection coils that detect and output the voltage induced when
The signal processing circuit comprises a single signal processing circuit for alternately switching the signals from the two magneto-impedance elements according to two pulse trains synchronized with the predetermined phase difference by switching means.
With magneto-impedance magnetic detector,
A ratio of outputs of the two magneto-impedance elements detected by the two magneto-impedance elements and alternately output from the signal processing circuit in accordance with the two pulse trains synchronized with the predetermined phase difference. Detects throttle opening based on
Is.
[0013]
The throttle opening detection device of the present invention (the second invention according to claim 2)
In the first invention,
The two magneto-impedance elements are arranged in an orthogonal relationship;
The arithmetic circuit calculates the rotation angle θ of the throttle opening detection magnet from the output Hx of one magneto-impedance element and the output Hy of the other magneto-impedance sensor element according to the relationship of Equation (1). is there.
[0014]
The throttle opening detection device of the present invention (the third invention according to claim 3),
In the second invention,
The two magneto-impedance elements comprise an amorphous wire and a sensing coil wound around the amorphous wire;
When the one signal processing circuit alternately holds the two magneto-impedance elements by alternately switching the pulse generator for energizing the pulse and holding two magnetic signals obtained in synchronization with the pulse generator for a predetermined time. It is a set of electronic circuits consisting of sample and hold circuits that output in series
Is.
[0015]
The throttle opening degree detection device of the present invention (the fourth invention according to claim 4),
In the third invention,
The detection coil and the set of electronic circuits are formed on the same substrate.
Is.
[0016]
Operation and effect of the invention
The throttle opening detection device of the first invention having the above-described configuration includes a magnetic sensor for detecting a magnetic field by a rotating throttle opening detection magnet, a signal processing circuit for signal processing of a change in the detected magnetic field, and the signal processing circuit In the throttle opening degree detecting device provided with an arithmetic circuit for calculating the throttle opening degree based on the output signal output from the above, the two magneto-impedance elements constituting the magnetic sensor arranged in different directions are configured. The pulse currents of two pulse trains that are set with repetition frequency and pulse width and synchronized with a predetermined phase difference are marked on the two amorphous wires. Addition The output detected by the two detection coils wound around the two amorphous wires with the voltage induced when the signal is generated is transferred to the predetermined signal by a switching means in one signal processing circuit constituting the signal processing circuit. The signal obtained by alternately switching in accordance with two pulse trains synchronized with each other in phase difference is processed and detected by the two magneto-impedance elements in the arithmetic circuit according to the two pulse trains synchronized in the predetermined phase difference. Since the throttle opening is detected based on the ratio of the outputs of the two magneto-impedance elements alternately output from the signal processing circuit, when one of the magneto-impedance elements is operating, the other magneto-impedance is detected. Because the element is not operating, the other magneto-impedance On the magnetic circuit and mechanism for preventing the occurrence of errors due to the change in the distance between the magnet and the magnetoelectric transducer, while enabling highly accurate detection of the throttle opening, since it is not affected by electromagnetic effects due to the operation of the element. The above device is not required, and there is an effect that the stability is high and the size is reduced without being affected by a change in magnetic field strength or a change in sensitivity of the magnetoelectric transducer.
[0017]
The throttle opening degree detecting device of the second invention having the above-described configuration is the first invention, wherein the signal processing circuit has an output Hx of one magneto-impedance element and the other magneto-impedance sensor element in which the signal processing circuits are arranged in an orthogonal relationship. Since the rotation angle θ of the throttle opening detection magnet is calculated from the output Hy of the above-mentioned equation according to the relationship of Equation 1, in order to prevent the occurrence of errors due to the change in the distance between the magnet and the magnetoelectric transducer. This eliminates the need for a device on the magnetic circuit and mechanism, and has the effect of being highly stable and miniaturized without being affected by changes in magnetic field strength or sensitivity changes of the magnetoelectric transducer.
[0018]
In the throttle opening degree detecting device of the third invention having the above-described configuration, in the second invention, the two magneto-impedance elements cause an ambient magnetic field when a pulse current is applied to the amorphous wire around the amorphous wire. A voltage is induced by the wound detection coil, and the electronic circuit as the one signal processing circuit is synchronized with the pulse energization of a pulse generator that alternately energizes the two magneto-impedance elements to perform the pulse energization. Since the two magnetic signals obtained by the sample-and-hold circuit are alternately held for a predetermined time and output in time series, when one magneto-impedance element is operating with pulse energization, the other magneto-impedance element is pulsed Because they are not energized and not operating, Because it is not affected by the electromagnetic effects caused by the pulse current of the magneto-impedance element, it can detect the throttle opening with high accuracy and does not perform simultaneous signal processing in the electronic circuit, thus reducing power consumption. This makes it possible to achieve the effect of simplifying the processing circuit.
[0019]
In the throttle opening degree detecting device of the fourth invention having the above-mentioned configuration, in the third invention, the two magneto-impedance elements and the one set of electronic circuits are formed on the same substrate. Since the characteristics of two sensors can be aligned, high-accuracy measurement is possible, the sensor can be made smaller, higher sensitivity can be achieved, the processing circuit can be simplified, and the overall size can be reduced to reduce weight and power consumption. There is an effect of reducing.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0021]
(First embodiment)
The throttle opening detection device of the first embodiment includes a magnetic sensor 2 for detecting a magnetic field by a rotating throttle opening detection magnet 1 as shown in FIGS. 1 and 2, and a signal indicating a change in the detected magnetic field. In the throttle opening detecting device including the signal processing circuit 23 to be processed and the arithmetic circuit 3 for calculating the throttle opening based on the output signal output from the signal processing circuit, the magnetic sensor 2 is arranged in different directions. The two magneto-impedance elements 21 and 22 are used, and the signal processing circuit 23 performs signal processing by alternately switching the outputs from the two magneto-impedance elements 21 and 22 by switching means. A magneto-impedance magnetic detector 20 composed of the signal processing circuit of FIG. A throttle opening is detected based on a ratio of outputs of the two magneto-impedance elements 21 and 22 detected by the impedance elements 21 and 22 and alternately output from the signal processing circuit 23. From the output Hx of the impedance element 21 and the output Hy of the other magneto-impedance sensor element 22, the rotation angle θ of the throttle opening detection magnet 1 is calculated according to the relationship of the equation (1).
[0022]
As shown in FIG. 1, the basic configuration of the throttle opening detection device of the first embodiment is that the angle between the magnet 1 attached to the rotary shaft 10 and the magnetoelectric conversion element for detecting the magnetic field of this magnet is predetermined. A magneto-impedance magnetic detector 2 composed of two magneto-impedance elements 21 and 22 set at an angle, and one signal processing circuit 23 for alternately switching and outputting the two magnetic signals, and the two magnets The angle calculation device 3 is an arithmetic circuit that calculates a rotation angle based on a signal ratio.
[0023]
The magnetic sensor according to the first embodiment includes two magneto-impedance elements 21 and 22 whose axes are set to have a predetermined angle, and detect each axial component of the magnetic field of the rotating magnet 1. The ratio of the two magnetic signals is calculated by the angle calculation device 3 and the rotation angle is output.
[0024]
FIG. 2 is a plan view showing that two magneto-impedance elements 21 and 22 are arranged in a magnetic field of strength B by the magnet 1 and the sensitivity axes x and y are set at a predetermined angle α. It is.
[0025]
Here, an angle θ formed with the magnetic field with reference to the x-axis of one of the magneto-impedance elements 21 is defined as a rotation angle. FIG. 2 shows a state where the rotation angle of the magnetic field B is θ. At this time, the angle between the y-axis of the other magneto-impedance element 22 and the magnetic field is α−θ. Therefore, the magnetic field strengths Hx and Hy detected by the two magnetoelectric conversion elements 21 and 22 are expressed by Equations 2 and 3.
[Expression 2]

[Equation 3]

[0026]
Since both Hx and Hy are functions of the rotation angle θ and both have angle information, it is possible to detect either Hx or Hy as an angle signal. Many use this principle.
However, since both the formulas 2 and 3 have the magnetic field strength B as a coefficient, if the value of B changes, Hx and Hy change and an error occurs.
[0027]
For example, if the rotary shaft 10 to which the magnet 1 is attached has a backlash and the relative distance from the magnetoelectric transducer changes or becomes unstable, the magnetic field strength changes in proportion to the reciprocal of the distance, so the output fluctuates and an error occurs. Cause. In general, since the magnetic field strength of a magnet has a temperature coefficient, the magnetic field strength B also changes due to a temperature change, resulting in an error.
[0028]
Therefore, the angle calculation device 3 in the first embodiment calculates the ratio of the outputs of the two magneto-impedance elements 21 and 22, and obtains the angle based on the ratio. That is, the ratio Hy / Hx of the outputs of the two magneto-impedance elements 21 and 22 is as shown in Equation 4, and the term of the magnetic field strength B of the numerator and denominator of Hy / Hx is eliminated, so The influence of fluctuations in magnetic field strength due to temperature changes can be eliminated. Further, since Hy / Hx is the output of the magneto-impedance elements 21 and 22, for example, even if there is a sensitivity change in the two magneto-impedance elements 21 and 22 due to a temperature change, this is also the same. Since it is erased, highly accurate measurement is possible.
[Expression 4]

As can be seen from Equation 4, the relationship between the angle θ and Hy / Hx is generally non-linear.
[0029]
Next, when α is set to 90 degrees, the above equation 4 is cos (90−θ) / cos θ = tan θ. Therefore, by calculating arctan (Hy / Hx) as in the above equation 1, Hy / Hx is obtained. Based on this, θ can be obtained linearly.
[0030]
Accordingly, it is possible to perform angle measurement with good linear relation and more stable and high accuracy by calculation from the magnetic signals in the x and y axis directions detected by the two magneto-impedance elements 21 and 22.
[0031]
Next, the magneto-impedance magnetic detector 20 as the magnetoelectric transducer is made of an amorphous wire and can be operated at a high temperature of 120 ° C. The signals of the two magneto-impedance elements are alternately switched in time series. In order to carry out the processing, it is sufficient to prepare one electronic circuit, and the cost can be further reduced.
[0032]
The angle calculation device 3 calculates arctan (Hy / Hx) from the output signals Hy and Hx of the signal processing circuit 23 and outputs an angle signal.
[0033]
Further, as described above, the throttle opening detection device according to the first embodiment is provided with a mechanism component that stabilizes the distance between the magnetic sensor and the magnet so that the magnetic field applied to the magnetoelectric transducer does not change as in the prior art. In addition, there is no need to take countermeasures such as electromagnetic compensation for stabilizing the magnetic field strength or the sensor sensitivity, so that a small and inexpensive angle sensor can be realized.
[0034]
(Second Embodiment)
The throttle opening degree detection device of the second embodiment corresponds to the configuration of FIG. 1, and details are shown in FIG. The magnet 1 attached to the rotating shaft 10 is the same as that shown in FIG.
[0035]
The magneto-impedance magnetic detector 20 includes two magneto-impedance elements and one common signal processing circuit. The two magneto-impedance elements 21 and 22 of the x-axis and the y-axis are disposed in the rotating magnetic field in order to detect signals of respective axial components at an angle α of 90 degrees.
[0036]
The magneto-impedance elements 21 and 22 are formed by winding a detection coil around an amorphous wire. When a pulse current is passed through the amorphous wire, a voltage corresponding to the axial component of the surrounding magnetic field is instantaneously induced in the detection coil. Is done. A magnetic field signal can be obtained by signal processing the voltage induced in the detection coil.
[0037]
The signal processing circuit 23 is for processing signals from the two magneto-impedance elements 21 and 22, and includes a pulse generator 231 and a sample hold circuit 232.
[0038]
The pulse generator 231 generates two pulse trains having a repetition frequency of 2 MHz, a pulse width of several tens of ns (nanoseconds), and synchronized with a predetermined phase difference, and from each of the terminals P1 and P2 and P3 and P4, respectively. The output is switched alternately with a period of 5 μs (microseconds). Further, the output terminal P5 outputs a synchronization signal when the pulse train is alternately switched every 5 μs, and this is output to the subsequent angle calculation device 3.
[0039]
Since the output terminals P1 and P3 of the pulse generator 231 are connected to the amorphous wires of the two magneto-impedance elements 21 and 22 of the x-axis and y-axis, a current of a pulse train of 2 MHz is alternately applied every 5 μs. . When a pulse is applied, a voltage corresponding to the surrounding magnetic field is instantaneously induced in each detection coil of the magneto-impedance elements 21 and 22.
[0040]
The pulses of the output terminals P2 and P4 of the pulse generator 231 are applied to the control terminals of the analog switches S1 and S2, but the pulses of the terminals P1 and P2 and the pulses of P3 and P4 are synchronized as described above. When a pulse is applied, the switch is “closed” for a very short period of time, and a voltage corresponding to the magnetic field instantaneously induced in the detection coils of the magneto-impedance elements 21 and 22 is held in the capacitor C.
[0041]
As described above, since the pulse train applied to the magneto-impedance elements 21 and 22 is 2 MHz, the measurement of the magnetic field is intermittently executed at a repetition frequency of 2 MHz. However, the analog switches S1 and S2, the capacitor C, and the amplifier A are used. Form a sample and hold circuit 232, the signal at the output terminal P6 has a substantially continuous waveform.
[0042]
However, as described above, since the pulse generator 231 alternately outputs a pulse train with a set of P1 and P2 and a set of P3 and P4 with a period of 5 μs, the signal at the output terminal P6 of the magneto-impedance magnetic detector 2 is Magnetic signals detected by the magneto-impedance elements 21 and 22, that is, magnetic field signals of the x and y direction components are alternately output in time series.
[0043]
4 represents the magnetic field applied to the magneto-impedance elements on the x and y axes when the magnet 1 in FIG. 1 rotates at a constant rotational angular velocity. Thus, the horizontal axis is time and angle. b represents the signal waveform of the output terminal P6 of the magneto-impedance magnetic detector 2 at this time. In FIG. 5B, the symbols X and Y indicate that the outputs of the magneto-impedance elements 21 and 22 corresponding to the x and y axes are alternately switched with a period of 5 μs as described above. This b is exaggerated and broadly drawn with respect to the speed of changing the angle for the time width of switching between x and y for convenience of understanding. Therefore, the angle information is not interrupted practically.
[0044]
The angle calculation device 3 mainly comprises an A / D converter 31 and a microcomputer 32, calculates the rotation angle by software based on the ratio of the x direction component and the y direction component of the rotating magnetic field, and outputs it from the output terminal P7.
[0045]
The magnetic field signal of P6 is connected to the A / D converter 31, and the magnetic field signals of the x and y direction components that are alternately switched in time series are sequentially digitally converted. At this time, a switching signal at the terminal P5 of the pulse generator 231 is inputted to the microcomputer 32 as a synchronizing signal in order to discriminate the A / D converted signal into x-axis data and y-axis data.
[0046]
That is, when the switching signal of 5 μs output from the terminal P5 of the pulse generator 231 is a logic level “1”, the computer 32 sets the x-direction magnetic field signal as x and the y-direction magnetic field signal as “0”. Align y-axis data.
[0047]
The angle calculation calculation is performed by software based on the A / D converted data. Here, the relationship between the angle and the output signal is linearly calculated by calculating θ = arctan (Hy / Hx) based on the equation (1). Turn into.
[0048]
FIG. 5 is an example of the calculation result of the angle θ, and shows that the output is linear with respect to the angle change. In the second embodiment, the signal changes linearly from negative to positive with respect to the 180 ° region where the angular change is from −90 ° to + 90 °, and the output is repeated for further angular changes. Become.
[0049]
As described above, according to the second embodiment, the rotating magnetic field due to the rotation of the magnet 1 is detected by the two magneto-impedance elements 21 and 22, and the angle is calculated from the ratio of the signals, thereby affecting the influence of the magnetic field fluctuation and the sensitivity change of the magnetoelectric transducer. In addition to enabling stable and highly accurate angle detection without being subjected to the above, it is possible to realize such an angle sensor.
[0050]
Further, in the second embodiment, when one magneto-impedance element is operated with pulse energization, the other magneto-impedance element is not operated because it is not energized with pulse. Because it is not affected by the electromagnetic operation caused by the operation of the pulse of the element, it can detect the rotational speed with high accuracy and does not perform simultaneous signal processing in the signal processing circuit, so there is no interference in signal processing. The power consumption can be reduced.
[0051]
(Third embodiment)
The throttle opening detection device according to the third embodiment is an integrated circuit in which a single signal processing circuit 23 that performs signal processing by switching in time series with two magneto-impedance elements 21 and 22 as the magneto-impedance magnetism detector 2 It is configured as a small element and can be easily arranged in a rotating magnetic field.
[0052]
That is, as shown in FIG. 6, the magneto-impedance magnetic detector 200 uses amorphous wires 201 and 203 having a length of 2 mm and a diameter of 30 μm around which detection coils 202 and 204 are wound as magneto-impedance elements. The signal processing circuits 205 which are arranged orthogonally to each other and formed in the vicinity thereof are arranged on the same substrate. The signal processing circuit 205 processes the signals of the two magneto-impedance elements 21 and 22 by switching as in the above-described embodiment.
[0053]
In addition, the throttle opening detection device of the third embodiment is formed by integrally forming two magneto-impedance elements 21 and 22 and one signal processing circuit 23 on a substrate, so that two Sensor characteristics can be matched, enabling high-accuracy measurement, making the sensor smaller, enabling higher sensitivity, simplifying the processing circuit, reducing the overall size, and reducing weight and power consumption. The effect of doing.
[0054]
Furthermore, the entire device is reduced in size by being housed in a 2 mm × 3 mm IC package 207 provided with wiring electrodes 206 and can be easily mounted in the rotating magnetic field.
[0055]
In addition, by using amorphous wire as the material of the magneto-impedance element, it is possible to measure even in the temperature range of 120 ° C or more, which is normal for magnetoelectric transducers, and as a throttle position sensor for engines with severe temperature environment, stable and highly accurate measurement This makes it possible to reduce the size and price.
[0056]
【Example】
Hereinafter, examples of magnetic detectors that can be used in the throttle opening detection device of the above-described embodiment will be described with reference to the drawings.
[0057]
(Example)
The magnetic detector of the present embodiment is reduced in size and increased in sensitivity in consideration of application in the automobile field as shown in FIG. 7, and will be described below with reference to FIGS.
[0058]
The substrate 100 of the two magneto-impedance elements 21 and 22 constituting the magnetic detector 2 has a width of 0.5 mm, a height of 0.5 mm, a length in the longitudinal direction of 3 mm, Reference numeral 220 denotes an amorphous wire having a diameter of 30 μm using a CoFeSiB alloy. The electromagnetic coils 211 and 221 include one side 211A and 221A of the coil formed on the groove surface 100S of the groove 100G formed in the longitudinal direction of the substrate 100, and the remaining one side coil 211B formed on the groove upper surface 112 of the groove 100G. It is formed by a two-layer structure of 221B.
[0059]
The one side 211A, 221A of the coil formed on the groove surface 111 and the groove upper surface 112, and the other side coil 211B, 221B are grooves formed in the longitudinal direction of the electrode wiring board 100 as shown in FIGS. A conductive magnetic metal thin film that forms a coil is formed by vapor deposition in a range that is somewhat wider than the groove upper surface 112 of 100G, and a conductive metal thin film portion that forms a gap is selected so that the formed metal thin film remains spirally. By removing by an etching method, the entire length of the coil in the longitudinal direction is formed to be 1.5 mm or 2 mm. Note that FIG. 8 shows a state in which coils are formed in a square shape on the four surfaces of the entire surface of the groove 100G for convenience of understanding regardless of the AA ′ cross section of FIG.
[0060]
The inner diameter equivalent to the circle (the diameter of the circle having the same area as the groove cross-sectional area formed by the height and width) of the electromagnetic coils 211 and 221 is desirably 200 μm or 100 μm or less, and thus set to 66 μm as an example. Since the winding interval per turn (per unit length) of the electromagnetic coils 211 and 221 is preferably 100 μm / turn or less, it is set to 50 μm / turn as an example.
[0061]
The length of the element substrate is 3 mm, and the amorphous wires 210 and 220 and the electromagnetic coils 211 and 221 of the two magneto-impedance elements 21 and 22 are electrode wiring as one element substrate as shown in FIG. The electronic circuit 23 (not shown) formed integrally on the substrate 100 and connected via electrodes disposed at both ends of the magnetic detectors 21 and 22 is also formed on one electrode wiring substrate 100. The sensor output from the electronic circuit 23 is shown in FIG. 9 where the horizontal axis represents the external magnetic field and the vertical axis represents the output voltage.
[0062]
The magnetic detector of the present embodiment realizes miniaturization, thinning, and small volume (width 0.5 mm, height 0.5 mm, length in the longitudinal direction 3 mm) in consideration of application in the automotive field. However, as is apparent from FIG. 9, linear output up to a full scale of 0.2 V at 40 gauss (G) is obtained, and linear measurement and highly sensitive measurement are realized.
[0063]
Further, in the magnetic detector of this embodiment, the amorphous wires 210 and 220 of the two magneto-impedance elements 21 and 22 and the electromagnetic coils 211 and 221 as detection coils are integrally formed on the entire substrate, and the magnetic detection The electronic circuit 23 as the signal processing circuit connected through the electrodes disposed at both ends of the containers 21 and 22 is also formed on the same whole substrate, disposed in the same package, and used as the two detection coils. Since the electromagnetic coil and the electronic circuit are mounted on the same substrate, the characteristics of the two sensors can be matched, enabling high-precision measurement and making the sensor small and highly sensitive. The processing circuit can be simplified, the overall size can be reduced, and the weight and power consumption can be reduced.
[0064]
In addition, since the magnetic detector of the present embodiment employs an amorphous wire as a magneto-impedance element, it can operate stably even in a temperature environment of 120 ° C. due to the original nature of the amorphous wire. Stable operation is possible even in the environment, and there is an effect that it is suitable for detecting the throttle opening.
[0065]
Furthermore, in the magnetic detector of this embodiment, in order to make the magneto-impedance element a more sensitive magnetic sensor, the radius of the equivalent circular inner diameter of the electromagnetic coils 211 and 221 as the detection coils should be 200 μm or 100 μm or less. Desirably, in this embodiment, it is set to 66 μm as an example, and is effective for increasing the electromagnetic coupling between the amorphous wire and the detection coil by making it extremely small, and also effective for thinning the sensor and reducing the capacity. It is.
[0066]
In addition, the magnetic detector of this embodiment can be made small and easy to handle by mounting (loading) the two magneto-impedance elements and the signal processing circuit on a single substrate. Further, the magneto-impedance element Because of its high sensitivity, stable magnetic measurement can be performed even if the gap with the rotating body is increased to 1 mm or more, so there is no need for precise assembly work when mounting on a car, so the production cost is greatly reduced. Play.
[0067]
Further, in this embodiment, two magneto-impedance elements are manufactured by an automatic machine controlled with a predetermined accuracy, and two driver circuits of a pulse generator composed of IC circuits for driving the two magneto-impedance elements, respectively. In order to make the drive characteristics and the switch characteristics of the two analog switches of the sample and hold circuits corresponding to each other the same, the mask design is performed so that the circuits are formed in close proximity to each other, and the characteristics of the two magneto-impedance elements are mutually connected. Since they are made equal, the characteristics of the two magneto-impedance elements can be made equal to each other.
[0068]
In this embodiment, the substrate 100 has a width of 0.5 mm, a height of 0.5 mm, a length in the longitudinal direction of 3 mm, and the length of the amorphous wire is 3 mm or less. As can be seen from Fig. 9, a linear output is obtained up to 0.2V full scale at 40 gauss, so in order to eliminate the conventional hysteresis and non-linear characteristics, another coil is provided in the amorphous wire and the feedback current is supplied to this. This eliminates the need for a feedback technique to flow or bias current. As a result, it is not necessary to always flow a direct current, and power consumption can be reduced. Also, the bias coil can be omitted and the magneto-impedance element is simplified.
[0069]
The above-described embodiments have been illustrated for the purpose of explanation, and the present invention is not limited thereto. Those skilled in the art will recognize from the claims, the detailed description of the invention, and the description of the drawings. Modifications and additions can be made without departing from the technical idea of the present invention.
[0070]
As described in the above embodiment, the present invention performs magnetic field strength by measuring an angle based on a ratio of two magnetic field signals accompanying rotation of the throttle opening detection magnet 1 attached to the rotating shaft 10. It is stable against changes in the sensitivity of the magnetoelectric transducer and in the high temperature range, and also realizes a small and inexpensive throttle opening sensor that can be used for magnets other than the throttle opening detection magnet. If the rotation angle is detected by the magneto-impedance element, it can be applied to a purpose of detecting the rotation angle of a rotation element other than the throttle opening.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a throttle opening degree detection device according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram for explaining a measurement principle in the throttle opening detection device of the first embodiment.
FIG. 3 is a detailed block diagram showing a throttle opening degree detection device according to a second embodiment of the present invention.
FIG. 4 is a diagram showing an output waveform in the throttle opening detection device of the second embodiment.
FIG. 5 is a diagram showing a relationship of an output change with respect to an angle change in the steering angle detection device of the second embodiment.
FIG. 6 is a plan view showing a package of a magneto-impedance magnetic detector according to a third embodiment of the present invention.
FIG. 7 is a plan view showing a magnetic detector in an embodiment of the present invention.
FIG. 8 is a cross-sectional view taken along line AA ′ in FIG. 7 showing the magnetic detector in the present embodiment.
FIG. 9 is a diagram showing the relationship between the external magnetic field and output voltage of the magnetic detector in the present example. FIG.
[Explanation of symbols]
1 Throttle opening detection magnet
2 Magnetic sensor
20 Magneto-impedance magnetic detector
21, 22 Magneto impedance element
23 Signal processing circuit
3 Arithmetic circuit

Claims (4)

A magnetic sensor that detects a magnetic field by a rotating throttle opening detection magnet, a signal processing circuit that performs signal processing on the detected change in the magnetic field, and an operation that calculates the throttle opening based on an output signal output from the signal processing circuit In the throttle opening detection device equipped with a circuit,
The magnetic sensor is composed of two magneto-impedance elements arranged in different directions,
Said two magneto-impedance element is wound and two amorphous wire pulse current of two pulse train synchronized with a predetermined phase difference repetition frequency and pulse width are set are marked pressure, to the two amorphous wire pulse current consists of a two detection coils for detecting and outputting a voltage induced when it is marked pressurized,
A magneto-impedance comprising a single signal processing circuit, wherein the signal processing circuit performs signal processing by alternately switching the outputs from the two magneto-impedance elements according to two pulse trains synchronized with the predetermined phase difference by switching means. With a magnetic detector,
A ratio of outputs of the two magneto-impedance elements detected by the two magneto-impedance elements and alternately output from the signal processing circuit in accordance with the two pulse trains synchronized with the predetermined phase difference. Detecting the throttle opening based on the throttle opening detection device. In claim 1,
The two magneto-impedance elements are arranged in an orthogonal relationship;
The arithmetic circuit calculates the rotation angle θ of the throttle opening detection magnet from the output Hx of one magneto-impedance element and the output Hy of the other magneto-impedance sensor element by the relationship of Equation 1.

A throttle opening detector. In claim 2,
The two magneto-impedance elements comprise an amorphous wire and a sensing coil wound around the amorphous wire;
When the one signal processing circuit alternately holds the two magneto-impedance elements by alternately switching a pulse generator for energizing a pulse and two magnetic signals obtained in synchronization with the pulse generator for a predetermined time. A throttle opening detecting device, characterized in that it is a set of electronic circuits comprising a sample-and-hold circuit for outputting in series. In claim 3,
The throttle opening detecting device, wherein the detection coil and the set of electronic circuits are formed on the same substrate.

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