JP2004117101A

JP2004117101A - Magnetic encoder device

Info

Publication number: JP2004117101A
Application number: JP2002278903A
Authority: JP
Inventors: Toshiyuki Harada; 原田　敏行
Original assignee: Yaskawa Electric Corp
Current assignee: Yaskawa Electric Corp
Priority date: 2002-09-25
Filing date: 2002-09-25
Publication date: 2004-04-15

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic encoder device which can suppress leaking magnetic field due to a bias magnet toward the outside of a motor, by making the magnetic flux emitted from the bias magnet of a magnetic sensor close in a small area. <P>SOLUTION: In the magnetic encoder device 1 having a rotating disk 2 for detecting the position where a magnetic path part 11 and a magnetic shield part 12 are formed alternately by a slit track 4, that is made by radially forming the slits at a prescribed pitch over the total circumference of an annular soft-magnetic body, a magnetic sensor 3 which is disposed opposite the rotating disk 2, at a prescribed position via a spacing, and which is composed of the bias magnet 6 and a magnetic detector element 7, and a signal processing circuit 15 for processing the signal from the magnetic sensor 3, n pieces of auxiliary magnets 8 are arranged around the magnetic sensor 3. The auxiliary magnet 8 has 1/n magnetomotive force, and has a magnetization vector having a direction which is opposite to that of the bias magnet. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、磁気式エンコーダ装置に関するものである。
【０００２】
【従来の技術】
従来、磁気式エンコーダ装置は図６のようになっている。図６は第１従来技術を示す磁気式エンコーダ装置の斜視図である。
図６において、１は磁気式エンコーダ装置、２は回転ディスク、３は磁気センサ、４はスリットトラック、６はバイアス磁石、７は磁気検知素子、９はモータ、１０はシャフト、１１は磁気通路部、１２は磁気遮蔽部、１５は信号処理回路、矢印は磁石の磁化ベクトルの向きを示している。
図６に示す磁気式エンコーダ装置１は、回転ディスク２と磁気センサ３によって構成されている。回転ディスク２はモータ９のシャフト１０に取り付けられており、シャフト１０の回転と共にその軸心を中心に回転するようになっている。また、回転ディスク２上には環状の軟磁性体板が設けられており、軟磁性体板の全周にわたって放射状にスリットを所定ピッチで形成したスリットトラック４によって磁気抵抗が小なる磁気通路部１１と磁気抵抗が大なる磁気遮蔽部１２とを回転ディスク２の回転方向に沿うように交互に形成している。磁気センサ３は、スリットトラック４と空隙を介して所定の位置に対向配置されており、スリットトラック４と対向するように配置されたバイアス磁石６と、スリットトラック４とバイアス磁石６の間に配置されると共にバイアス磁石６の磁束の変化を検出する磁気検知素子７とによって構成されている。
以下にこの磁気式エンコーダ装置の動作について説明する。
回転ディスク２が回転して磁気通路部１１が磁気センサ３に近づくと磁気抵抗が小さくなるので、バイアス磁石６からの磁束が増え磁気センサ３に加わる磁束が増加する。更に回転ディスク２が回転して磁気遮蔽部１２が磁気センサ３に近づくと、磁気抵抗が大きくなりバイアス磁石６からの磁束が減るので磁気センサ３に加わる磁束が減少する。このように、回転ディスク２が回転すると磁気センサ３に作用する磁束が周期的に変化することになり、この磁束の変化を磁気検知素子７で検出し、信号処理回路１５を介して回転ディスク２に施されたスリットトラック４のピッチに応じた検出信号が出力されるようになっている。
【０００３】
また、第２従来技術として、回転ディスク上に第１従来技術のようなスリットトラックを径方向に複数段設け、夫々のスリットトラックのスリットピッチを所定の異なるピッチとすると共に夫々のスリットトラックに対して磁気センサを対向配置することにより、複数の信号が検出できるようにしたものもある（例えば、特許文献１参照）。
【０００４】
【特許文献１】
特開平１０‐２９３０４２号公報（第３頁、第４頁、第１図、第４図）
【０００５】
更に、第３従来技術として図７のようなものがある。図７は第３従来例を示す磁気式エンコーダ装置の斜視図である。
図７において、１は磁気式エンコーダ装置、２は回転ディスク、３は磁気センサ、５は歯車、６はバイアス磁石、７は磁気検知素子、９はモータ、１０はシャフト、１３は歯車の歯部、１４は歯車の溝部、１５は信号処理回路、矢印は磁石の磁化ベクトルの向きを示している。
図７に示す磁気式エンコーダ装置は、第１従来技術においてスリットトラックによって形成されていた磁気通路部１１と磁気遮蔽部１２を、歯車５によって形成したものである。歯車５は軟磁性体よりなると共に回転ディスク２の外周に全周にわたり所定ピッチで形成されたものであり、磁気センサ３が歯車５と空隙を介して所定の位置に対向配置されている。磁気センサ３は、歯車５と対向するように配置されたバイアス磁石６と、歯車５とバイアス磁石６の間に配置されると共にバイアス磁石６の磁束の変化を検出する磁気検知素子７とによって構成されている。
この磁気式エンコーダ装置の動作は、第１従来技術と同様に、回転ディスク２が回転することにより磁気通路部に相当する歯車５の歯部１３と磁気遮蔽部に相当する歯車５の溝部１４とが交互に磁気センサ３に近づくことで、磁気センサ３に作用するバイアス磁石６からの磁束が周期的に変化するので、この磁束の変化を磁気検知素子７で検出し、信号処理回路１５を介して歯車５のピッチに応じた検出信号が出力されるようになっている。
【０００６】
【発明が解決しようとする課題】
ところが、図６に示す第１従来技術、図７に示す第３従来技術のような磁気式エンコーダ装置では、磁気センサを単独で用いる場合、バイアス磁石も１個となるためバイアス磁石より発せられる磁束が狭い範囲で閉じにくくなり、その結果、モータ外部への漏洩磁場が大きくなり、周囲の機器に影響を及ぼすという問題があった。
また、第２従来技術のようなスリットトラックを回転ディスクの径方向に複数段設け、夫々のスリットトラックに対して磁気センサを用いる場合でも、隣り合う磁気センサのバイアス磁石同士の磁化ベクトルがすべて同じであるため、磁束が狭い範囲で閉じにくくなり、第１および第３従来技術と同様の問題を生じていた。
【０００７】
本発明は、上記課題を解決するためになされたものであり、磁気センサのバイアス磁石から発せられる磁束が狭い範囲で閉じるようにし、バイアス磁石によるモータ外部への漏洩磁場を抑えることができる磁気式エンコーダ装置を提供することを目的とする。
【０００８】
【課題を解決するための手段】
上記問題を解決するため、請求項１の本発明は、環状の軟磁性体の全周にわたって放射状にスリットを所定ピッチで形成してなるスリットトラックによって磁気抵抗が小なる磁気通路部と磁気抵抗が大なる磁気遮蔽部を交互に形成した位置の検出を行う回転ディスクと、前記回転ディスクと空隙を介して所定の位置に対向配置される磁気センサと、前記磁気センサからの信号を処理する信号処理回路を備え、前記磁気センサは、前記磁気通路部及び前記磁気遮蔽部と対向するように配置されたバイアス磁石と、前記回転ディスクと前記バイアス磁石の間に配置された磁気検知素子によって構成される磁気式エンコーダ装置において、前記磁気センサの近傍にｎ個（ｎは１以上の整数）の補助磁石を配置すると共に、前記補助磁石は、前記バイアス磁石の１／ｎの起磁力を有し、且つ、前記バイアス磁石の磁化ベクトルと逆向きになるような磁化ベクトルを有したものである。
【０００９】
請求項２の本発明は、環状の軟磁性体の全周にわたって放射状にスリットを所定ピッチで形成してなるスリットトラックによって磁気抵抗が小なる磁気通路部と磁気抵抗が大なる磁気遮蔽部を交互に形成した位置の検出を行う回転ディスクと、前記回転ディスクと空隙を介して所定の位置に対向配置される磁気センサと、前記磁気センサからの信号を処理する信号処理回路を備え、前記磁気センサは、前記磁気通路部及び前記磁気遮蔽部と対向するように配置されたバイアス磁石と、前記回転ディスクと前記バイアス磁石の間に配置された磁気検知素子によって構成される磁気式エンコーダ装置において、前記回転ディスクは前記位置検出用のスリットを有する位置検出用のスリットトラックと、モータ磁極検出用のスリットを有するモータ磁極検出用のスリットトラックと、原点位置検出用のスリットを有する原点位置検出用のスリットトラックとより構成されると共に、前記夫々のスリットトラックは径方向に沿って設けられ、前記夫々のスリットトラックの位置に前記磁気センサを対向して設けると共に、前記磁極検出用のスリットトラックの位置に設けた磁気センサは互いに近接して複数設けられ、かつ、隣り合う磁気センサのバイアス磁石同士の磁化ベクトルが互いに逆向きになるように配置してあり、前記位置検出用のスリットトラックと前記原点位置検出用のスリットトラックの夫々の位置に設けた磁気センサは互いに近接して設けられ、該磁気センサのバイアス磁石の磁化ベクトルを互いに逆向きとしたものである。
【００１０】
請求項３の本発明は、環状の軟磁性体の外周にわたって放射状に歯部と溝部を所定ピッチで形成してなる歯車によって磁気抵抗が小なる磁気通路部と磁気抵抗が大なる磁気遮蔽部を交互に形成した位置の検出を行う回転ディスクと、前記回転ディスクと空隙を介して所定の位置に対向配置される磁気センサと、前記磁気センサからの信号を処理する信号処理回路を備え、前記磁気センサは、前記磁気通路部及び前記磁気遮蔽部と対向するように配置されたバイアス磁石と、前記回転ディスクと前記バイアス磁石の間に配置された磁気検知素子によって構成される磁気式エンコーダ装置において、前記磁気センサの近傍にｎ個（ｎは１以上の整数）の補助磁石を配置すると共に、前記補助磁石は、前記バイアス磁石の１／ｎの起磁力を有し、且つ、前記バイアス磁石の磁化ベクトルと逆向きになるような磁化ベクトルを有したものである。
【００１１】
請求項４の本発明は、環状の軟磁性体の外周にわたって放射状に歯部と溝部を所定ピッチで形成してなる歯車によって磁気抵抗が小なる磁気通路部と磁気抵抗が大なる磁気遮蔽部を交互に形成した位置の検出を行う回転ディスクと、前記回転ディスクと空隙を介して所定の位置に対向配置される磁気センサと、前記磁気センサからの信号を処理する信号処理回路を備え、前記磁気センサは前記磁気通路部及び前記磁気遮蔽部と対向するように配置されたバイアス磁石と、前記回転ディスクと前記バイアス磁石の間に配置された磁気検知素子とによって構成される磁気式エンコーダ装置において、前記回転ディスクは位置検出用の歯部と溝部を有する位置検出用の歯車と、モータ磁極検出用の歯部と溝部を有するモータ磁極検出用の歯車と、原点位置検出用の歯部と溝部を有する原点位置検出用の歯車とより構成されると共に、前記夫々の歯車は軸方向に沿って設けられ、前記夫々の歯車の位置に前記磁気センサを設けると共に、前記磁極検出用の歯車の位置に設けた磁気センサは互いに近接して複数設けられ、かつ、隣り合う磁気センサのバイアス磁石同士の磁化ベクトルが互いに逆向きになるように配置してあり、前記位置検出用の歯車と前記原点位置検出用の歯車の夫々の位置に設けた磁気センサは互いに近接して設けられ、該磁気センサのバイアス磁石の磁化ベクトルを互いに逆向きとしたものである。
【００１２】
【発明の実施の形態】
以下、本発明の実施例を図に基づいて説明する。
［第１実施例］
図１は本発明の第１実施例を示す磁気式エンコーダ装置の斜視図である。なお、本発明の構成要素が従来技術と同じものについては同一符号を付してその説明を省略し、異なる点のみ説明する。
図１において、８は補助磁石を示している。
第１実施例が第１従来技術と異なる点は以下のとおりである、
すなわち、磁気センサ３の周囲にｎ個（ｎは１以上の整数）の補助磁石を配置すると共に、補助磁石８は、バイアス磁石６の１／ｎの起磁力を有し、且つ、バイアス磁石の磁化ベクトルと逆向きになるような磁化ベクトルを有した点である。
【００１３】
本発明の第１実施例は、環状の軟磁性体の全周にわたって放射状にスリットを所定ピッチで形成してなるスリットトラック４によって磁気抵抗が小なる磁気通路部１１と磁気抵抗が大なる磁気遮蔽部１２を交互に形成した位置の検出を行う回転ディスク２と、回転ディスク２と空隙を介して所定の位置に対向配置される磁気センサ３と、磁気センサ３からの信号を処理する信号処理回路１５を備え、磁気センサ３は、磁気通路部１１及び磁気遮蔽部１２と対向するように配置されたバイアス磁石６と、回転ディスク２とバイアス磁石６の間に配置された磁気検知素子７によって構成される磁気式エンコーダ装置１において、磁気センサ３の周囲にｎ個の補助磁石８を配置し、バイアス磁石の１／ｎの起磁力を有し且つバイアス磁石の磁化ベクトルと逆向きになるような磁化ベクトルを有する補助磁石８としたので、バイアス用磁石より発せられる磁束が狭い範囲で閉じるようになり、磁気センサのバイアス磁石によるモータ外部への漏洩磁場を抑えることが可能な磁気式エンコーダ装置を提供することができる。その結果、周囲機器に及ぶ磁場の影響が小さくなるため、周囲機器への漏洩磁場対策が不要となり、システムの小形・軽量化および低コスト化を図ることができる。
【００１４】
［第２実施例］
図２は本発明の第２実施例を示す磁気式エンコーダ装置の斜視図である。
図２において、３ａ〜３ｈは磁気センサ、４ａ〜４ｃはスリットトラック、６ａ〜６ｈはバイアス磁石、７ａ〜７ｈは磁気検知素子、１１ａ〜１１ｃは磁気通路部、１２ａ〜１２ｃは磁気遮蔽部を示している。なお、信号処理回路の図示は省略している。
第２実施例が第１実施例と異なる点は以下のとおりである、
すなわち、回転ディスク２に設けられた環状の軟磁性体板上には、最外周に６０°毎に磁気通路部１１ａと磁気遮蔽部１２ａが交互に形成されたモータ磁極検出用のスリットを有する磁極検出用のスリットトラック４ａと、スリットトラック４ａの内周側に所定のピッチで磁気通路部１１ｂと磁気遮蔽部１２ｂが交互に形成された位置検出用のスリットを有する位置検出用のスリットトラック４ｂと、更にスリットトラック４ｂの内周側に１箇所だけ磁気遮蔽部１２ｃとなるスリットを形成して残りの部分を磁気通路１１ｃとした源点位置検出用のスリットを有する原点位置検出用のスリットトラック４ｃとより構成されると共に、夫々のスリットトラックは径方向に沿って設けられている。
また、夫々のスリットトラックの位置に磁気センサを設けると共に、磁極検出用のスリットトラック４ａの位置に設けた磁気センサは、磁気検知素子近傍の磁束線が他方の磁気センサのバイアス磁石の影響で変位することによって回転ディスクの磁気通路部と磁気遮蔽部の判断に支障が生じることがない程度に互いに近接して複数個（３ａ〜３ｆ）設けられ、隣り合う磁気センサのバイアス磁石同士の磁化ベクトルが互いに逆向きになるように配置している。具体的には、磁気センサ３ａ、３ｂ、３ｃ内のバイアス磁石６ａ、６ｂ、６ｃの磁化ベクトルと磁気センサ３ｄ、３ｅ、３ｆ内のバイアス磁石６ｄ、６ｅ、６ｆの磁化ベクトルとが互いに逆向きとなっている。それから、当該磁気センサ３ａ〜３ｆのは位置については、磁極検出用のスリットトラック４ａと空隙を介して、夫々Ｕ相、Ｖ相、Ｗ相、−Ｕ相、−Ｖ相、−Ｗ相に対応した６つの磁極検出用の磁気センサ３ａ〜３ｆがＵ相、Ｖ相、Ｗ相信号間の位相差が電気的に夫々１２０°異なる信号となるように配置されている。該磁気センサ３ａ〜３ｆは、Ｕ相磁気センサ３ａを基準として、Ｖ相磁気センサ３ｂは＋４０°の位置に、Ｗ相磁気センサ３ｃは−４０°の位置に、−Ｕ相磁気センサ３ｄは−６０°の位置に、−Ｖ相磁気センサ３ｅは−２０°の位置に、−Ｗ相磁気センサ３ｆは＋２０°の位置に対向配置されている。
また、位置検出用のスリットトラック４ｂ及び原点位置検出用のスリットトラック４ｃは空隙を介して、夫々位置検出用の磁気センサ３ｇ、原点位置検出用の磁気センサ３ｈが所定の位置に対向配置されている。このとき、位置検出用の磁気センサ３ｇと原点位置検出用の磁気センサ３ｈは、互いの精度に影響を及ぼさない程度に近接して設けられ、磁気センサ３ｇ、３ｈ内のバイアス磁石６ｇ、６ｈの磁化ベクトルは互いに逆向きとする。
【００１５】
本発明の第２実施例は、環状の軟磁性体の全周にわたって放射状にスリットを所定ピッチで形成してなるスリットトラック４によって磁気抵抗が小なる磁気通路部１１と磁気抵抗が大なる磁気遮蔽部１２を交互に形成した位置の検出を行う回転ディスク２と、回転ディスク２と空隙を介して所定の位置に対向配置される磁気センサと、磁気センサからの信号を処理する信号処理回路１５を備え、磁気センサは、磁気通路部１１ａ、１１ｂ、１１ｃ及び磁気遮蔽部１２ａ、１２ｂ、１２ｃと対向するように配置されたバイアス磁石６ａと、回転ディスク２とバイアス磁石の間に配置された磁気検知素子によって構成される磁気式エンコーダ装置において、回転ディスク２上にスリットトラック４ａ〜４ｃを径方向に複数段設け、夫々のスリットトラック４ａ〜４ｃのスリットピッチを所定の異なるピッチとすると共に夫々のスリットトラック４ａ〜４ｃに対して磁気センサ３ａ〜３ｈを対向配置し、磁極検出用のスリットトラック４ａの位置に設けた磁気センサは互いに近接して複数個（３ａ〜３ｆ）設けられ、かつ、隣り合う磁気センサのバイアス磁石６ａ〜６ｆ同士の磁化ベクトルを互いに逆向きになるように配置し、位置検出用のスリットトラック４ｂと原点位置検出用のスリットトラック４ｃの夫々の位置に設けた磁気センサ３ｇ、３ｈを互いに近接して設け、該磁気センサ３ｇ、３ｈのバイアス磁石６ｇ、６ｈの磁化ベクトルを互いに逆向きとしたので、バイアス磁石より発せられる磁束が狭い範囲で閉じるようになり、バイアス磁石によるモータ外部への漏洩磁場が抑えることが可能な磁気式エンコーダ装置を提供することができる。その結果、周囲機器に及ぶ磁場の影響が小さくなるため、周囲機器への漏洩磁場対策が不要となり、システムの小形・軽量化および低コスト化を図ることができる。
【００１６】
［第３実施例］
図３は本発明の第３実施例を示す磁気式エンコーダ装置の斜視図である。
図３において、８は補助磁石を示している。
第３実施例が第２従来技術と異なる点は以下のとおりである。
すなわち、磁気センサの近傍にｎ個（ｎは１以上の整数）の補助磁石を配置すると共に、補助磁石８は、バイアス磁石の１／ｎの起磁力を有し、且つ、バイアス磁石の磁化ベクトルと逆向きになるような磁化ベクトルを有したものである。
【００１７】
本発明の第３実施例は、環状の軟磁性体の外周にわたって放射状に歯部１３と溝部１４を所定ピッチで形成してなる歯車５によって磁気抵抗が小なる磁気通路部と磁気抵抗が大なる磁気遮蔽部を交互に形成した位置の検出を行う回転ディスク２と、回転ディスク２と空隙を介して所定の位置に対向配置される磁気センサ３と、磁気センサ３からの信号を処理する信号処理回路１５を備え、磁気センサ３は、磁気通路部及び磁気遮蔽部と対向するように配置されたバイアス磁石６と、回転ディスク２とバイアス磁石６の間に配置された磁気検知素子７によって構成される磁気式エンコーダ装置において、磁気センサ３の周囲にｎ個の補助磁石８を配置し、バイアス磁石６の１／ｎの起磁力を有し且つバイアス磁石６の磁化ベクトルと逆向きになるような磁化ベクトルを有する補助磁石８としたので、バイアス用磁石６より発せられる磁束が狭い範囲で閉じるようになり、磁気センサ３のバイアス磁石６によるモータ外部への漏洩磁場を抑えることが可能な磁気式エンコーダ装置を提供することができる。その結果、周囲機器に及ぶ磁場の影響が小さくなるため、周囲機器への漏洩磁場対策が不要となり、システムの小形・軽量化および低コスト化を図ることができる。
【００１８】
図４は本発明の第４実施例を示す磁気式エンコーダ装置の斜視図である。
図４において、５は位置検出用の歯車で、１３、１４は夫々歯車５の歯部、溝部を示している。また、１８はモータ磁極検出用の歯車で、１６、１７は夫々歯車１８の歯部と溝部を示すと共に、２１は原点位置検出用の歯車で、１９、２０は夫々歯車２１の歯部と溝部を示し、２２ａ〜２２ｆは磁気センサを示している。なお、信号処理回路の図示は省略している。
第４実施例が第３実施例と異なる点は以下のとおりである。
すなわち、回転ディスク２に位置検出用の歯部１３と溝部１４を有する位置検出用の歯車５と、モータ磁極検出用の歯部１６と溝部１７を有するモータ磁極検出用の歯車１８と、原点位置検出用の歯部１９と溝部２０を有する原点位置検出用の歯車２１とより構成されると共に、該夫々の歯車は軸方向に沿って設けられ、夫々の歯車の位置に磁気センサ２２ａ〜２２ｈを設けると共に、磁極検出用の歯車１８の位置に設けた磁気センサ２２ａ〜２２ｆは、磁気検知素子近傍の磁束線が他方の磁気センサのバイアス磁石の影響で変位することによって回転ディスクの磁気通路部と磁気遮蔽部の判断に支障が生じることがない程度に近接して設けられ、かつ、隣り合う磁気センサ２２ａ〜２２ｆのバイアス磁石同士の磁化ベクトルが互いに逆向きになるように配置した点である。
また、夫々の歯車の位置に磁気センサを設けると共に、磁極検出用の歯車１８の位置に設けた磁気センサは近接して複数個（２２ａ〜２２ｆ）設けられ、隣り合う磁気センサ２２ａ〜２２ｆのバイアス磁石同士の磁化ベクトルが互いに逆向きになるように配置してあり、位置検出用の歯車５と原点位置検出用の歯車２１の夫々の位置に設けた磁気センサ２２ｇ、２２ｈは近接して設けられ、該磁気センサのバイアス磁石の磁化ベクトルを互いに逆向きとした点である。
【００１９】
本発明の第４実施例は、環状の軟磁性体の外周にわたって放射状に歯部と溝部を所定ピッチで形成してなる歯車によって磁気抵抗が小なる磁気通路部と磁気抵抗が大なる磁気遮蔽部を交互に形成した位置の検出を行う回転ディスク２と、回転ディスク２と空隙を介して所定の位置に対向配置される磁気センサと、磁気センサからの信号を処理する信号処理回路１５を備え、磁気センサは、磁気通路部及び磁気遮蔽部と対向するように配置されたバイアス磁石と、回転ディスクとバイアス磁石の間に配置された磁気検知素子によって構成される磁気式エンコーダ装置において、回転ディスク２に位置検出用の歯部１３と溝部１４を有する位置検出用の歯車５と、モータ磁極検出用の歯部１６と溝部１７を有するモータ磁極検出用の歯車１８と、原点位置検出用の歯部１９と溝部２０を有する原点位置検出用の歯車２１とより構成されると共に、該夫々の歯車は軸方向に沿って設けられ、夫々の歯車の位置に磁気センサ２２ａ〜２２ｈを設けると共に、磁極検出用の歯車の位置に設けた磁気センサは近接して複数個（２２ａ〜２２ｆ）設けられ、かつ、隣り合う磁気センサ２２ａ〜２２ｆのバイアス磁石同士の磁化ベクトルが互いに逆向きになるように配置してあり、位置検出用の歯車５と原点位置検出用の歯車２１の夫々の位置に設けた磁気センサ２２ｇ、２２ｈは近接して設けられ、該磁気センサ２２ｇ、２２ｈのバイアス磁石の磁化ベクトルを互いに逆向きとしたので、バイアス用磁石より発せられる磁束が狭い範囲で閉じるようになり、磁気センサのバイアス磁石によるモータ外部への漏洩磁場を抑えることが可能な磁気式エンコーダ装置を提供することができる。その結果、周囲機器に及ぶ磁場の影響が小さくなるため、周囲機器への漏洩磁場対策が不要となり、システムの小形・軽量化および低コスト化を図ることができる。
【００２０】
図５は本発明の磁気式エンコーダ装置における漏洩磁場低減の効果を示すグラフである。
図５は代表例として、第１実施例の磁気式エンコーダ装置における漏洩磁場低減の効果の確認を実施したものである。縦軸は漏洩磁場の比率を示したもので、磁石が磁気センサのバイアス磁石と補助磁石の２個ある場合（Ａ）、補助磁石の磁化ベクトルを磁気センサ内のバイアス磁石の磁化ベクトルとを互いに逆向きとすることでバイアス磁石の磁化ベクトルが共に同じ向きのとき（Ｂ）に対して約６０％漏洩磁束が減少する。また、補助磁石がない場合（Ｃ）に対しても約３０％漏洩磁束が減少する。
【００２１】
なお、本実施例では回転形のモータに適用されるロータリ形の磁気式エンコーダ装置について述べたが、リニアモータに適用されるリニア磁気式エンコーダ装置にも適用できることは明らかである。
【００２２】
【発明の効果】
以上に述べたように、本発明によれば以下の効果がある。
本発明の第１実施例は、環状の軟磁性体の全周にわたって放射状にスリットを所定ピッチで形成してなるスリットトラックによって磁気抵抗が小なる磁気通路部と磁気抵抗が大なる磁気遮蔽部を交互に形成した位置の検出を行う回転ディスクと、回転ディスクと空隙を介して所定の位置に対向配置される磁気センサと、磁気センサからの信号を処理する信号処理回路を備え、磁気センサは、磁気通路部及び磁気遮蔽部と対向するように配置されたバイアス磁石と、回転ディスクとバイアス磁石の間に配置された磁気検知素子によって構成される磁気式エンコーダ装置において、磁気センサの周囲にｎ個の補助磁石８を配置し、バイアス磁石の１／ｎの起磁力を有し且つバイアス磁石の磁化ベクトルと逆向きになるような磁化ベクトルを有する補助磁石８としたため、バイアス用磁石より発せられる磁束が狭い範囲で閉じるようになり、磁気センサのバイアス磁石によるモータ外部への漏洩磁場を抑えることが可能な磁気式エンコーダ装置を提供することができる。その結果、周囲機器に及ぶ磁場の影響が小さくなるため、周囲機器への漏洩磁場対策が不要となり、システムの小形・軽量化および低コスト化を図ることができる。
【００２３】
本発明の第２実施例は、環状の軟磁性体の全周にわたって放射状にスリットを所定ピッチで形成してなるスリットトラックによって磁気抵抗が小なる磁気通路部と磁気抵抗が大なる磁気遮蔽部を交互に形成した位置の検出を行う回転ディスクと、回転ディスクと空隙を介して所定の位置に対向配置される磁気センサと、磁気センサからの信号を処理する信号処理回路を備え、磁気センサは、磁気通路部及び磁気遮蔽部と対向するように配置されたバイアス磁石と、回転ディスクとバイアス磁石の間に配置された磁気検知素子によって構成される磁気式エンコーダ装置において、回転ディスクは位置検出用のスリットを有する位置検出用のスリットトラックと、モータ磁極検出用のスリットを有するモータ磁極検出用のスリットトラックと、原点位置検出用のスリットを有する原点位置検出用のスリットトラックとより構成されると共に、前記夫々のスリットトラックは径方向に沿って設けられ、前記夫々のスリットトラックの位置に前記磁気センサを対向して設けると共に、前記磁極検出用のスリットトラックの位置に設けた磁気センサは近接して複数設けられ、かつ、隣り合う磁気センサのバイアス磁石同士の磁化ベクトルが互いに逆向きになるように配置してあり、位置検出用のスリットトラックと原点位置検出用のスリットトラックの夫々の位置に設けた磁気センサは近接して設けられ、該磁気センサのバイアス磁石の磁化ベクトルを互いに逆向きとしたため、バイアス磁石より発せられる磁束が狭い範囲で閉じるようになり、バイアス磁石によるモータ外部への漏洩磁場が抑えることが可能な磁気式エンコーダ装置を提供することができる。その結果、周囲機器に及ぶ磁場の影響が小さくなるため、周囲機器への漏洩磁場対策が不要となり、システムの小形・軽量化および低コスト化を図ることができる。
【００２４】
本発明の第３実施例は、環状の軟磁性体の外周にわたって放射状に歯部と溝部を所定ピッチで形成してなる歯車によって磁気抵抗が小なる磁気通路部と磁気抵抗が大なる磁気遮蔽部を交互に形成した位置の検出を行う回転ディスクと、回転ディスクと空隙を介して所定の位置に対向配置される磁気センサと、磁気センサからの信号を処理する信号処理回路を備え、磁気センサは、磁気通路部及び磁気遮蔽部と対向するように配置されたバイアス磁石と、回転ディスクとバイアス磁石の間に配置された磁気検知素子によって構成される磁気式エンコーダ装置において、磁気センサの周囲にｎ個の補助磁石８を配置し、バイアス磁石の１／ｎの起磁力を有し且つバイアス磁石の磁化ベクトルと逆向きになるような磁化ベクトルを有する補助磁石８としたため、バイアス用磁石より発せられる磁束が狭い範囲で閉じるようになり、磁気センサのバイアス磁石によるモータ外部への漏洩磁場を抑えることが可能な磁気式エンコーダ装置を提供することができる。その結果、周囲機器に及ぶ磁場の影響が小さくなるため、周囲機器への漏洩磁場対策が不要となり、システムの小形・軽量化および低コスト化を図ることができる。
【００２５】
本発明の第４実施例は、環状の軟磁性体の外周にわたって放射状に歯部と溝部を所定ピッチで形成してなる歯車によって磁気抵抗が小なる磁気通路部と磁気抵抗が大なる磁気遮蔽部を交互に形成した位置の検出を行う回転ディスクと、回転ディスクと空隙を介して所定の位置に対向配置される磁気センサと、磁気センサからの信号を処理する信号処理回路を備え、磁気センサは、磁気通路部及び磁気遮蔽部と対向するように配置されたバイアス磁石と、回転ディスクとバイアス磁石の間に配置された磁気検知素子によって構成される磁気式エンコーダ装置において、回転ディスクに位置検出用の歯部と溝部を有する位置検出用の歯車と、モータ磁極検出用の歯部と溝部を有するモータ磁極検出用の歯車と、原点位置検出用の歯部と溝部を有する原点位置検出用の歯車とより構成されると共に、該夫々の歯車は軸方向に沿って設けられ、夫々の歯車の位置に磁気センサを設けると共に、磁極検出用の歯車の位置に設けた磁気センサは近接して複数設けられ、かつ、隣り合う磁気センサのバイアス磁石同士の磁化ベクトルが互いに逆向きになるように配置してあり、位置検出用の歯車と原点位置検出用の歯車の夫々の位置に設けた磁気センサは互いに近接して設けられ、該磁気センサのバイアス磁石の磁化ベクトルを互いに逆向きとしたため、第３実施例と同様にバイアス用磁石より発せられる磁束が狭い範囲で閉じるようになり、磁気センサのバイアス磁石によるモータ外部への漏洩磁場を抑えることが可能な磁気式エンコーダ装置を提供することができる。その結果、周囲機器に及ぶ磁場の影響が小さくなるため、周囲機器への漏洩磁場対策が不要となり、システムの小形・軽量化および低コスト化を図ることができる。
【図面の簡単な説明】
【図１】本発明の第１実施例を示す磁気式エンコーダ装置の斜視図である。
【図２】本発明の第２実施例を示す磁気式エンコーダ装置の斜視図である。
【図３】本発明の第３実施例を示す磁気式エンコーダ装置の斜視図である。
【図４】本発明の第４実施例を示す磁気式エンコーダ装置の斜視図である。
【図５】本発明の磁気式エンコーダ装置における漏洩磁場低減の効果を示すグラフである。
【図６】第１従来技術を示す磁気式エンコーダ装置の斜視図である。
【図７】第３従来技術を示す磁気式エンコーダ装置の斜視図である。
【符号の説明】
１：磁気式エンコーダ装置
２：回転ディスク
３、３ａ、３ｂ、３ｃ、３ｄ、３ｅ、３ｆ、３ｇ、３ｈ：磁気センサ
４、４ａ、４ｂ、４ｃ：スリットトラック
５：歯車（位置検出用）
６、６ａ、６ｂ、６ｃ、６ｄ、６ｅ、６ｆ、６ｇ、６ｈ：バイアス磁石
７、７ａ、７ｂ、７ｃ、７ｄ、７ｅ、７ｆ、７ｇ、７ｈ：磁気検知素子
８、８ａ、８ｂ：補助磁石
９　：モータ
１０：シャフト
１１、１１ａ、１１ｂ、１１ｃ：磁気通路部
１２ａ、１２ｂ、１２ｃ：磁気遮蔽部
１３：歯部
１４：溝部
１５：信号処理回路
１６：歯部
１７：溝部
１８：歯車（モータ磁極検出用）
１９：歯部
２０：溝部
２１：歯車（原点位置検出用）
２２ａ、２２ｂ、２２ｃ、２２ｄ、２２ｅ、２２ｆ、２２ｇ、２２ｈ：磁気センサ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetic encoder device.
[0002]
[Prior art]
Conventionally, a magnetic encoder device is as shown in FIG. FIG. 6 is a perspective view of a magnetic encoder device showing the first related art.
In FIG. 6, 1 is a magnetic encoder device, 2 is a rotary disk, 3 is a magnetic sensor, 4 is a slit track, 6 is a bias magnet, 7 is a magnetic sensing element, 9 is a motor, 10 is a shaft, and 11 is a magnetic path. , 12 are magnetic shielding parts, 15 is a signal processing circuit, and arrows indicate directions of magnetization vectors of magnets.
The magnetic encoder device 1 shown in FIG. 6 includes a rotating disk 2 and a magnetic sensor 3. The rotating disk 2 is attached to a shaft 10 of a motor 9, and rotates around its axis with the rotation of the shaft 10. An annular soft magnetic plate is provided on the rotating disk 2, and a magnetic track portion 11 having a small magnetic resistance is formed by slit tracks 4 in which slits are radially formed at a predetermined pitch all around the soft magnetic plate. And the magnetic shielding portion 12 having a large magnetic resistance are alternately formed along the rotation direction of the rotating disk 2. The magnetic sensor 3 is arranged opposite to the slit track 4 at a predetermined position via a gap, and is arranged between the slit track 4 and the bias magnet 6, and a bias magnet 6 arranged to face the slit track 4. And a magnetic sensing element 7 for detecting a change in the magnetic flux of the bias magnet 6.
The operation of the magnetic encoder device will be described below.
When the rotating disk 2 rotates and the magnetic path portion 11 approaches the magnetic sensor 3, the magnetic resistance decreases, so that the magnetic flux from the bias magnet 6 increases and the magnetic flux applied to the magnetic sensor 3 increases. Further, when the rotating disk 2 rotates and the magnetic shield 12 approaches the magnetic sensor 3, the magnetic resistance increases and the magnetic flux from the bias magnet 6 decreases, so that the magnetic flux applied to the magnetic sensor 3 decreases. As described above, when the rotating disk 2 rotates, the magnetic flux acting on the magnetic sensor 3 changes periodically. The change in the magnetic flux is detected by the magnetic sensing element 7, and the rotation of the rotating disk 2 is detected via the signal processing circuit 15. , A detection signal corresponding to the pitch of the slit track 4 applied is output.
[0003]
Further, as a second conventional technique, a plurality of slit tracks as in the first conventional technique are provided in a radial direction on a rotating disk, and the slit pitch of each slit track is set to a predetermined different pitch, and each slit track is provided with a different pitch. In some cases, a plurality of signals can be detected by arranging the magnetic sensors to face each other (for example, see Patent Document 1).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open Publication No. Hei 10-29342 (pages 3, 4, 4, 5)
[0005]
FIG. 7 shows a third conventional technique. FIG. 7 is a perspective view of a magnetic encoder device showing a third conventional example.
In FIG. 7, 1 is a magnetic encoder device, 2 is a rotating disk, 3 is a magnetic sensor, 5 is a gear, 6 is a bias magnet, 7 is a magnetic sensing element, 9 is a motor, 10 is a shaft, and 13 is a gear tooth. , 14 are gear grooves, 15 is a signal processing circuit, and arrows indicate the direction of the magnetization vector of the magnet.
In the magnetic encoder device shown in FIG. 7, the magnetic path portion 11 and the magnetic shielding portion 12 formed by the slit track in the first related art are formed by the gear 5. The gear 5 is made of a soft magnetic material and formed at a predetermined pitch all around the outer periphery of the rotary disk 2. The magnetic sensor 3 is arranged opposite to the gear 5 at a predetermined position via a gap. The magnetic sensor 3 includes a bias magnet 6 arranged to face the gear 5, and a magnetic sensing element 7 arranged between the gear 5 and the bias magnet 6 and detecting a change in magnetic flux of the bias magnet 6. Have been.
The operation of this magnetic encoder device is similar to that of the first prior art in that the rotation of the rotary disk 2 causes the teeth 13 of the gear 5 corresponding to the magnetic path and the grooves 14 of the gear 5 corresponding to the magnetic shield to rotate. Alternately approach the magnetic sensor 3, the magnetic flux from the bias magnet 6 acting on the magnetic sensor 3 changes periodically. This magnetic flux change is detected by the magnetic sensing element 7, Thus, a detection signal corresponding to the pitch of the gear 5 is output.
[0006]
[Problems to be solved by the invention]
However, in a magnetic encoder device such as the first prior art shown in FIG. 6 and the third prior art shown in FIG. 7, when the magnetic sensor is used alone, the number of bias magnets is one, so the magnetic flux generated from the bias magnets Is difficult to close in a narrow range, and as a result, there is a problem that a leakage magnetic field to the outside of the motor increases, which affects peripheral devices.
Further, even when a plurality of slit tracks are provided in the radial direction of the rotating disk as in the second related art, and the magnetic sensors are used for each slit track, the magnetization vectors of the bias magnets of the adjacent magnetic sensors are all the same. Therefore, the magnetic flux is difficult to close in a narrow range, and the same problem as in the first and third prior arts occurs.
[0007]
The present invention has been made in order to solve the above-described problems, and has a magnetic type in which a magnetic flux emitted from a bias magnet of a magnetic sensor is closed in a narrow range, and a leakage magnetic field to the outside of the motor due to the bias magnet is suppressed. It is an object to provide an encoder device.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention of claim 1 provides a magnetic track portion and a magnetic resistance having a low magnetic resistance by a slit track in which slits are radially formed at a predetermined pitch over the entire circumference of an annular soft magnetic material. A rotating disk for detecting a position where a large magnetic shielding portion is alternately formed, a magnetic sensor arranged to face a predetermined position via a gap with the rotating disk, and a signal processing for processing a signal from the magnetic sensor A circuit, wherein the magnetic sensor is configured by a bias magnet arranged to face the magnetic path portion and the magnetic shielding portion, and a magnetic sensing element arranged between the rotating disk and the bias magnet. In the magnetic encoder device, n (n is an integer of 1 or more) auxiliary magnets are arranged near the magnetic sensor, and the auxiliary magnet is Has a magnetomotive force of 1 / n of the scan magnet, and is one having a magnetization vector such that the magnetization vector in the opposite direction from the biasing magnet.
[0009]
According to a second aspect of the present invention, a magnetic track portion having a small magnetic resistance and a magnetic shielding portion having a large magnetic resistance are alternately formed by a slit track in which slits are radially formed at a predetermined pitch over the entire circumference of an annular soft magnetic material. A rotating disk for detecting a position formed on the rotating disk, a magnetic sensor disposed opposite to the rotating disk at a predetermined position via a gap, and a signal processing circuit for processing a signal from the magnetic sensor; In a magnetic encoder device configured by a bias magnet disposed so as to face the magnetic path portion and the magnetic shielding portion, and a magnetic sensing element disposed between the rotating disk and the bias magnet, The rotating disk has a slit track for position detection having the slit for position detection, and a motor having a slit for detecting a motor magnetic pole. A slit track for pole detection and a slit track for origin position detection having a slit for origin position detection, and each of the slit tracks is provided along the radial direction, and the slit track of each of the slit tracks is provided. A plurality of magnetic sensors provided at the position of the slit track for detecting the magnetic poles are provided in close proximity to each other, and the magnetization vectors of the bias magnets of the adjacent magnetic sensors are mutually set. The magnetic sensors provided at respective positions of the slit track for detecting the position and the slit track for detecting the origin position are provided so as to be opposite to each other, and a bias magnet of the magnetic sensor is provided. Are made to have opposite magnetization vectors.
[0010]
According to a third aspect of the present invention, there is provided a magnetic path portion having a low magnetic resistance and a magnetic shielding portion having a high magnetic resistance formed by a gear having teeth and grooves radially formed at a predetermined pitch over the outer periphery of an annular soft magnetic material. A rotating disk for detecting alternately formed positions, a magnetic sensor disposed opposite to the rotating disk at a predetermined position via a gap, and a signal processing circuit for processing a signal from the magnetic sensor; In the magnetic encoder device configured by a sensor, a bias magnet disposed so as to face the magnetic passage portion and the magnetic shield portion, and a magnetic sensing element disposed between the rotating disk and the bias magnet, N (n is an integer of 1 or more) auxiliary magnets are arranged in the vicinity of the magnetic sensor, the auxiliary magnet has a magnetomotive force of 1 / n of the bias magnet, and Are those having a magnetization vector such that the magnetization vector in the opposite direction from the biasing magnet.
[0011]
According to a fourth aspect of the present invention, there is provided a magnetic path portion having a low magnetic resistance and a magnetic shielding portion having a high magnetic resistance formed by a gear having teeth and grooves radially formed at a predetermined pitch over the outer periphery of an annular soft magnetic material. A rotating disk for detecting alternately formed positions, a magnetic sensor disposed opposite to the rotating disk at a predetermined position via a gap, and a signal processing circuit for processing a signal from the magnetic sensor; In a magnetic encoder device configured by a sensor, a bias magnet disposed so as to face the magnetic path portion and the magnetic shield portion, and a magnetic sensing element disposed between the rotating disk and the bias magnet, The rotating disk includes a gear for position detection having teeth and grooves for position detection, a gear for motor pole detection having teeth and grooves for motor pole detection, and an original gear. A gear for origin position detection having a tooth portion for position detection and a groove portion, and each gear is provided along an axial direction, and the magnetic sensor is provided at a position of each gear, A plurality of magnetic sensors provided at the position of the gear for magnetic pole detection are provided in close proximity to each other, and are arranged such that magnetization vectors of bias magnets of adjacent magnetic sensors are opposite to each other. The magnetic sensors provided at the respective positions of the detection gear and the origin position detection gear are provided close to each other, and the magnetization vectors of the bias magnets of the magnetic sensors are set to be opposite to each other.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First embodiment]
FIG. 1 is a perspective view of a magnetic encoder device showing a first embodiment of the present invention. The components of the present invention that are the same as those of the prior art are denoted by the same reference numerals, description thereof will be omitted, and only different points will be described.
In FIG. 1, reference numeral 8 denotes an auxiliary magnet.
The first embodiment differs from the first prior art in the following points.
That is, while n (n is an integer of 1 or more) auxiliary magnets are arranged around the magnetic sensor 3, the auxiliary magnet 8 has a magnetomotive force of 1 / n of the bias magnet 6, and This is a point having a magnetization vector that is opposite to the magnetization vector.
[0013]
In the first embodiment of the present invention, a magnetic track portion 11 having a low magnetic resistance and a magnetic shield having a high magnetic resistance are provided by a slit track 4 in which slits are radially formed at a predetermined pitch over the entire circumference of an annular soft magnetic material. A rotating disk 2 for detecting a position where the portions 12 are alternately formed, a magnetic sensor 3 disposed opposite to the rotating disk 2 at a predetermined position via a gap, and a signal processing circuit for processing a signal from the magnetic sensor 3 The magnetic sensor 3 includes a bias magnet 6 arranged to face the magnetic passage 11 and the magnetic shield 12, and a magnetic sensing element 7 arranged between the rotating disk 2 and the bias magnet 6. In the magnetic encoder device 1, n auxiliary magnets 8 are arranged around the magnetic sensor 3 to have a magnetomotive force of 1 / n of the bias magnet and a magnetization vector of the bias magnet. Since the auxiliary magnet 8 has a magnetization vector that is opposite to the direction of the magnetic field, the magnetic flux emitted from the bias magnet is closed in a narrow range, and the leakage magnetic field to the outside of the motor due to the bias magnet of the magnetic sensor is suppressed. It is possible to provide a magnetic encoder device capable of performing the following. As a result, the influence of the magnetic field on the peripheral devices is reduced, so that it is not necessary to take measures against the leakage magnetic field to the peripheral devices, and it is possible to reduce the size, weight, and cost of the system.
[0014]
[Second embodiment]
FIG. 2 is a perspective view of a magnetic encoder device according to a second embodiment of the present invention.
In FIG. 2, 3a to 3h indicate magnetic sensors, 4a to 4c indicate slit tracks, 6a to 6h indicate bias magnets, 7a to 7h indicate magnetic sensing elements, 11a to 11c indicate magnetic passages, and 12a to 12c indicate magnetic shields. ing. The illustration of the signal processing circuit is omitted.
The differences between the second embodiment and the first embodiment are as follows.
That is, a magnetic pole having a motor magnetic pole detecting slit in which magnetic passage portions 11a and magnetic shield portions 12a are alternately formed at the outermost periphery at intervals of 60 ° on an annular soft magnetic plate provided on the rotating disk 2. A slit track 4a for detection, and a slit track 4b for position detection having slits for position detection in which magnetic passage portions 11b and magnetic shielding portions 12b are alternately formed at a predetermined pitch on the inner peripheral side of the slit track 4a. Further, a slit serving as a magnetic shielding portion 12c is formed only at one position on the inner peripheral side of the slit track 4b, and the remaining portion has a slit for detecting a source point position having a magnetic path 11c. And each slit track is provided along the radial direction.
A magnetic sensor is provided at the position of each slit track, and the magnetic sensor provided at the position of the slit track 4a for detecting the magnetic pole is such that the magnetic flux lines near the magnetic sensing element are displaced by the influence of the bias magnet of the other magnetic sensor. By doing so, a plurality (3a to 3f) are provided close to each other so as not to hinder the determination of the magnetic path portion and the magnetic shielding portion of the rotating disk, and the magnetization vectors of the bias magnets of adjacent magnetic sensors are They are arranged to be opposite to each other. Specifically, the magnetization vectors of the bias magnets 6a, 6b, 6c in the magnetic sensors 3a, 3b, 3c and the magnetization vectors of the bias magnets 6d, 6e, 6f in the magnetic sensors 3d, 3e, 3f are opposite to each other. Has become. Then, the positions of the magnetic sensors 3a to 3f correspond to the U-phase, V-phase, W-phase, -U-phase, -V-phase, and -W-phase through the slit track 4a for magnetic pole detection and the gap, respectively. The six magnetic pole detection magnetic sensors 3a to 3f are arranged such that the phase differences between the U-phase, V-phase, and W-phase signals are electrically different from each other by 120 °. The magnetic sensors 3a to 3f are based on the U-phase magnetic sensor 3a, the V-phase magnetic sensor 3b is at a position of + 40 °, the W-phase magnetic sensor 3c is at a position of −40 °, and the −U-phase magnetic sensor 3d is − At the position of 60 °, the −V-phase magnetic sensor 3e is disposed at the position of −20 °, and the −W-phase magnetic sensor 3f is disposed at the position of + 20 °.
Further, the slit track 4b for detecting the position and the slit track 4c for detecting the origin position are each provided with a magnetic sensor 3g for detecting the position and a magnetic sensor 3h for detecting the origin position opposed to predetermined positions via a gap. I have. At this time, the position detecting magnetic sensor 3g and the origin position detecting magnetic sensor 3h are provided so close to each other that they do not affect each other's accuracy, and the bias magnets 6g, 6h in the magnetic sensors 3g, 3h are provided. The magnetization vectors are opposite to each other.
[0015]
In the second embodiment of the present invention, a magnetic track portion 11 having a low magnetic resistance and a magnetic shield having a high magnetic resistance are provided by a slit track 4 in which slits are radially formed at a predetermined pitch over the entire circumference of an annular soft magnetic material. The rotating disk 2 for detecting the position where the portions 12 are alternately formed, the magnetic sensor disposed opposite to the rotating disk 2 at a predetermined position via a gap, and a signal processing circuit 15 for processing a signal from the magnetic sensor The magnetic sensor includes a bias magnet 6a disposed so as to face the magnetic passages 11a, 11b, 11c and the magnetic shields 12a, 12b, 12c, and a magnetic sensor disposed between the rotating disk 2 and the bias magnet. In a magnetic encoder device composed of elements, a plurality of slit tracks 4a to 4c are provided on the rotary disk 2 in the radial direction, The magnetic sensors provided with the slit pitches of the racks 4a to 4c at predetermined different pitches, the magnetic sensors 3a to 3h arranged opposite to the respective slit tracks 4a to 4c, and provided at the positions of the slit tracks 4a for detecting the magnetic poles. A plurality (3a to 3f) are provided close to each other, and the magnetization vectors of the bias magnets 6a to 6f of the adjacent magnetic sensors are arranged so as to be opposite to each other. Since the magnetic sensors 3g and 3h provided at the respective positions of the slit track 4c for position detection are provided close to each other, and the magnetization vectors of the bias magnets 6g and 6h of the magnetic sensors 3g and 3h are set to be opposite to each other, the bias The magnetic flux emitted from the magnet is closed in a narrow range, and the leakage magnetic field to the outside of the motor due to the bias magnet is suppressed. It is possible to provide a magnetic encoder apparatus capable. As a result, the influence of the magnetic field on the peripheral devices is reduced, so that it is not necessary to take measures against the leakage magnetic field to the peripheral devices, and it is possible to reduce the size, weight, and cost of the system.
[0016]
[Third embodiment]
FIG. 3 is a perspective view of a magnetic encoder device according to a third embodiment of the present invention.
In FIG. 3, reference numeral 8 denotes an auxiliary magnet.
The differences between the third embodiment and the second prior art are as follows.
That is, while n (n is an integer of 1 or more) auxiliary magnets are arranged near the magnetic sensor, the auxiliary magnet 8 has a magnetomotive force of 1 / n of the bias magnet and a magnetization vector of the bias magnet. The magnetization vector has a direction that is opposite to the above.
[0017]
In the third embodiment of the present invention, the gear 5 having the teeth 13 and the grooves 14 formed at a predetermined pitch radially around the outer periphery of the annular soft magnetic body has a magnetic path portion having a small magnetic resistance and a large magnetic resistance. A rotating disk 2 for detecting a position where magnetic shielding portions are alternately formed, a magnetic sensor 3 disposed opposite to the rotating disk 2 at a predetermined position via a gap, and a signal processing for processing a signal from the magnetic sensor 3 The magnetic sensor 3 includes a circuit 15, and the magnetic sensor 3 includes a bias magnet 6 arranged to face the magnetic path and the magnetic shield, and a magnetic sensing element 7 arranged between the rotating disk 2 and the bias magnet 6. In the magnetic encoder device, n auxiliary magnets 8 are arranged around the magnetic sensor 3 so that the auxiliary magnets 8 have a magnetomotive force of 1 / n of the bias magnet 6 and are opposite to the magnetization vector of the bias magnet 6. Since the auxiliary magnet 8 having such a magnetization vector is used, the magnetic flux emitted from the bias magnet 6 is closed in a narrow range, and the leakage magnetic field to the outside of the motor due to the bias magnet 6 of the magnetic sensor 3 can be suppressed. A magnetic encoder device can be provided. As a result, the influence of the magnetic field on the peripheral devices is reduced, so that it is not necessary to take measures against the leakage magnetic field to the peripheral devices, and it is possible to reduce the size, weight, and cost of the system.
[0018]
FIG. 4 is a perspective view of a magnetic encoder device according to a fourth embodiment of the present invention.
In FIG. 4, reference numeral 5 denotes a gear for position detection, and reference numerals 13 and 14 denote teeth and grooves of the gear 5, respectively. Reference numeral 18 denotes a gear for detecting the magnetic pole of the motor, 16 and 17 denote teeth and grooves of the gear 18, respectively, 21 denotes a gear for detecting the origin position, and 19 and 20 denote teeth and grooves of the gear 21. And 22a to 22f indicate magnetic sensors. The illustration of the signal processing circuit is omitted.
The differences between the fourth embodiment and the third embodiment are as follows.
That is, the position detecting gear 5 having the position detecting teeth 13 and the groove 14 on the rotating disk 2, the motor magnetic pole detecting gear 18 having the motor magnetic pole detecting teeth 16 and the groove 17, and the origin position It is composed of a tooth 21 for detection and a gear 21 for detecting an origin position having a groove 20. The respective gears are provided along the axial direction, and magnetic sensors 22a to 22h are provided at the positions of the respective gears. The magnetic sensors 22a to 22f provided at the positions of the magnetic pole detecting gears 18 are provided with magnetic flux lines near the magnetic sensing element displaced by the influence of the bias magnet of the other magnetic sensor, thereby providing Magnetization vectors of the bias magnets of the magnetic sensors 22a to 22f adjacent to each other are provided so as not to interfere with the determination of the magnetic shielding unit and are opposite to each other. In that it arranged so.
A magnetic sensor is provided at the position of each gear, and a plurality of magnetic sensors (22a to 22f) provided at the position of the magnetic pole detecting gear 18 are provided close to each other, and the bias of the magnetic sensors 22a to 22f adjacent to each other is provided. Magnetization vectors of the magnets are arranged to be opposite to each other, and the magnetic sensors 22g and 22h provided at the respective positions of the position detecting gear 5 and the origin position detecting gear 21 are provided close to each other. And that the magnetization vectors of the bias magnets of the magnetic sensor are made opposite to each other.
[0019]
The fourth embodiment of the present invention relates to a magnetic path portion having a low magnetic resistance and a magnetic shielding portion having a high magnetic resistance formed by gears having teeth and grooves radially formed at a predetermined pitch over the outer periphery of an annular soft magnetic material. A rotating disk 2 for detecting a position where the rotating disk 2 is alternately formed, a magnetic sensor disposed opposite to the rotating disk 2 at a predetermined position via a gap, and a signal processing circuit 15 for processing a signal from the magnetic sensor. The magnetic sensor is a magnetic encoder device including a bias magnet disposed so as to face the magnetic path portion and the magnetic shield portion, and a magnetic sensing element disposed between the rotary disk and the bias magnet. A position detecting gear 5 having a position detecting tooth 13 and a groove 14, a motor magnetic pole detecting gear 18 having a motor magnetic pole detecting tooth 16 and a groove 17, It is composed of a tooth portion 19 for detecting a point position and a gear 21 for detecting an origin position having a groove portion 20. The respective gears are provided along the axial direction, and the magnetic sensors 22a to 22c are provided at the positions of the respective gears. 22h, a plurality of magnetic sensors (22a to 22f) are provided in proximity to the gears for detecting magnetic poles, and the magnetization vectors of the bias magnets of the adjacent magnetic sensors 22a to 22f are opposite to each other. The magnetic sensors 22g and 22h provided at the respective positions of the position detection gear 5 and the origin position detection gear 21 are provided in close proximity to each other. Since the magnetization vectors of the bias magnets are opposite to each other, the magnetic flux emitted from the bias magnets is closed in a narrow range, and the motor using the bias magnets of the magnetic sensor It is possible to provide a magnetic encoder device capable of suppressing the leakage magnetic field to the part. As a result, the influence of the magnetic field on the peripheral devices is reduced, so that it is not necessary to take measures against the leakage magnetic field to the peripheral devices, and it is possible to reduce the size, weight, and cost of the system.
[0020]
FIG. 5 is a graph showing the effect of reducing the leakage magnetic field in the magnetic encoder device of the present invention.
FIG. 5 shows, as a representative example, confirmation of the effect of reducing the leakage magnetic field in the magnetic encoder device of the first embodiment. The vertical axis shows the ratio of the leakage magnetic field. When there are two magnets, the bias magnet and the auxiliary magnet of the magnetic sensor (A), the magnetization vector of the auxiliary magnet is compared with the magnetization vector of the bias magnet in the magnetic sensor. By making the direction opposite, the leakage magnetic flux is reduced by about 60% compared to (B) when the magnetization vectors of the bias magnets are both in the same direction. In addition, the leakage magnetic flux is reduced by about 30% in the case where there is no auxiliary magnet (C).
[0021]
In this embodiment, the rotary magnetic encoder applied to the rotary motor has been described. However, it is obvious that the present invention can be applied to a linear magnetic encoder applied to a linear motor.
[0022]
【The invention's effect】
As described above, the present invention has the following effects.
In the first embodiment of the present invention, a magnetic track portion having a small magnetic resistance and a magnetic shielding portion having a large magnetic resistance are formed by a slit track formed by radially forming slits at a predetermined pitch over the entire circumference of an annular soft magnetic material. A rotating disk that performs detection of alternately formed positions, a magnetic sensor disposed to face a predetermined position via a rotating disk and a gap, and a signal processing circuit that processes a signal from the magnetic sensor. In a magnetic encoder device including a bias magnet disposed so as to face a magnetic path portion and a magnetic shield portion and a magnetic sensing element disposed between a rotating disk and a bias magnet, n magnetic sensors are provided around a magnetic sensor. Are arranged, and have a magnetomotive force of 1 / n of that of the bias magnet and a magnetization vector that is opposite to the magnetization vector of the bias magnet. Since the auxiliary magnet 8 is used, the magnetic flux generated from the bias magnet is closed in a narrow range, and a magnetic encoder device capable of suppressing the leakage magnetic field to the outside of the motor due to the bias magnet of the magnetic sensor can be provided. . As a result, the influence of the magnetic field on the peripheral devices is reduced, so that it is not necessary to take measures against the leakage magnetic field to the peripheral devices, and it is possible to reduce the size, weight, and cost of the system.
[0023]
In the second embodiment of the present invention, a magnetic track portion having a small magnetic resistance and a magnetic shielding portion having a large magnetic resistance are formed by a slit track formed by radially forming slits at a predetermined pitch over the entire circumference of an annular soft magnetic material. A rotating disk that performs detection of alternately formed positions, a magnetic sensor disposed to face a predetermined position via a rotating disk and a gap, and a signal processing circuit that processes a signal from the magnetic sensor. In a magnetic encoder device including a bias magnet disposed so as to face the magnetic path and the magnetic shield and a magnetic sensing element disposed between the rotary disk and the bias magnet, the rotary disk is used for position detection. A slit track for detecting the position of the motor having a slit, a slit track for detecting the magnetic pole of the motor having a slit for detecting the magnetic pole of the motor, And a slit track for detecting an origin position having a slit for position detection, and each of the slit tracks is provided along a radial direction, and the magnetic sensor faces the position of each of the slit tracks. A plurality of magnetic sensors provided at the position of the slit track for detecting the magnetic pole are provided in close proximity to each other, and are arranged such that the magnetization vectors of the bias magnets of adjacent magnetic sensors are opposite to each other. The magnetic sensors provided at the respective positions of the slit track for detecting the position and the slit track for detecting the origin position are provided close to each other, and the magnetization vectors of the bias magnets of the magnetic sensors are opposite to each other. The generated magnetic flux closes in a narrow range, and the leakage magnetic field to the outside of the motor due to the bias magnet is reduced. It is possible to provide a magnetic encoder apparatus which can obtain. As a result, the influence of the magnetic field on the peripheral devices is reduced, so that it is not necessary to take measures against the leakage magnetic field to the peripheral devices, and it is possible to reduce the size, weight, and cost of the system.
[0024]
A third embodiment of the present invention is directed to a magnetic path portion having a low magnetic resistance and a magnetic shielding portion having a high magnetic resistance formed by a gear having teeth and grooves radially formed at a predetermined pitch over the outer circumference of an annular soft magnetic material. A rotating disk for detecting a position where the rotating disk is formed alternately, a magnetic sensor arranged to face a predetermined position via the rotating disk and a gap, and a signal processing circuit for processing a signal from the magnetic sensor. , A magnetic encoder device including a bias magnet arranged to face the magnetic passage portion and the magnetic shield portion, and a magnetic sensing element arranged between the rotating disk and the bias magnet, wherein n is provided around the magnetic sensor. And the auxiliary magnets 8 having a magnetomotive force of 1 / n of the bias magnet and having a magnetization vector in a direction opposite to the magnetization vector of the bias magnet. Since the magnetic flux emanating from the biasing magnet is to close in a narrow range, it is possible to provide a magnetic encoder device capable of suppressing the leakage magnetic field to the outside of the motor due to the bias magnet of the magnetic sensor. As a result, the influence of the magnetic field on the peripheral devices is reduced, so that it is not necessary to take measures against the leakage magnetic field to the peripheral devices, and it is possible to reduce the size, weight, and cost of the system.
[0025]
The fourth embodiment of the present invention relates to a magnetic path portion having a low magnetic resistance and a magnetic shielding portion having a high magnetic resistance formed by gears having teeth and grooves radially formed at a predetermined pitch over the outer periphery of an annular soft magnetic material. A rotating disk for detecting a position where the rotating disk is formed alternately, a magnetic sensor arranged to face a predetermined position via the rotating disk and a gap, and a signal processing circuit for processing a signal from the magnetic sensor. In a magnetic encoder device including a bias magnet arranged to face a magnetic path portion and a magnetic shield portion and a magnetic sensing element arranged between the rotating disk and the bias magnet, a position detection is performed on the rotating disk. A gear for detecting a position having teeth and grooves, a gear for detecting a motor magnetic pole having teeth and grooves for detecting a motor magnetic pole, and a tooth and a groove for detecting an origin position. And a magnetic sensor provided at the position of each gear, and a magnetic sensor provided at a position of the magnetic pole detection gear. Are provided in proximity to each other, and are arranged such that the magnetization vectors of the bias magnets of the adjacent magnetic sensors are opposite to each other, and the respective positions of the position detection gear and the origin position detection gear are Are provided close to each other, and the magnetization vectors of the bias magnets of the magnetic sensors are set to be opposite to each other, so that the magnetic flux emitted from the bias magnet is closed in a narrow range as in the third embodiment. Thus, it is possible to provide a magnetic encoder device capable of suppressing the leakage magnetic field to the outside of the motor due to the bias magnet of the magnetic sensor. As a result, the influence of the magnetic field on the peripheral devices is reduced, so that it is not necessary to take measures against the leakage magnetic field to the peripheral devices, and it is possible to reduce the size, weight, and cost of the system.
[Brief description of the drawings]
FIG. 1 is a perspective view of a magnetic encoder device according to a first embodiment of the present invention.
FIG. 2 is a perspective view of a magnetic encoder device according to a second embodiment of the present invention.
FIG. 3 is a perspective view of a magnetic encoder device according to a third embodiment of the present invention.
FIG. 4 is a perspective view of a magnetic encoder device according to a fourth embodiment of the present invention.
FIG. 5 is a graph showing an effect of reducing a leakage magnetic field in the magnetic encoder device of the present invention.
FIG. 6 is a perspective view of a magnetic encoder device showing a first related art.
FIG. 7 is a perspective view of a magnetic encoder device showing a third related art.
[Explanation of symbols]
1: Magnetic encoder device
2: Rotating disk
3, 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h: Magnetic sensor
4, 4a, 4b, 4c: slit track
5: Gear (for position detection)
6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h: bias magnet
7, 7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h: magnetic sensing element
8, 8a, 8b: auxiliary magnet
9: Motor
10: Shaft
11, 11a, 11b, 11c: magnetic path portion
12a, 12b, 12c: magnetic shield
13: Tooth
14: groove
15: Signal processing circuit
16: Tooth
17: Groove
18: Gear (for detecting magnetic pole of motor)
19: Tooth
20: groove
21: Gear (for detecting the origin position)
22a, 22b, 22c, 22d, 22e, 22f, 22g, 22h: magnetic sensor

Claims

A slit track in which slits are radially formed at a predetermined pitch over the entire circumference of an annular soft magnetic body is used to detect a position where a magnetic passage portion having a small magnetic resistance and a magnetic shielding portion having a large magnetic resistance are alternately formed. A rotating disk, a magnetic sensor disposed opposite to the rotating disk at a predetermined position via a gap, and a signal processing circuit for processing a signal from the magnetic sensor,
The magnetic encoder device includes a bias magnet disposed to face the magnetic path and the magnetic shield, and a magnetic sensing element disposed between the rotating disk and the bias magnet. At
N (n is an integer of 1 or more) auxiliary magnets are arranged near the magnetic sensor, and the auxiliary magnet has a magnetomotive force of 1 / n of the bias magnet, and magnetizes the bias magnet. A magnetic encoder device having a magnetization vector that is opposite to the vector.

A slit track in which slits are radially formed at a predetermined pitch over the entire circumference of an annular soft magnetic body is used to detect a position where a magnetic passage portion having a small magnetic resistance and a magnetic shielding portion having a large magnetic resistance are alternately formed. A rotating disk, a magnetic sensor disposed opposite to the rotating disk at a predetermined position via a gap, and a signal processing circuit for processing a signal from the magnetic sensor,
The magnetic encoder device includes a bias magnet disposed to face the magnetic path and the magnetic shield, and a magnetic sensing element disposed between the rotating disk and the bias magnet. At
The rotating disk has a slit track for position detection having a slit for position detection, a slit track for motor magnetic pole detection having a slit for motor pole detection, and an origin position detection slit having a slit for origin position detection. And each slit track is provided along the radial direction,
The magnetic sensors are provided at the positions of the respective slit tracks so as to face each other, and a plurality of magnetic sensors provided at the positions of the slit tracks for detecting the magnetic poles are provided in close proximity to each other, and the bias magnets of the adjacent magnetic sensors are provided. Are arranged such that their magnetization vectors are opposite to each other,
The magnetic sensors provided at the respective positions of the slit track for detecting the position and the slit track for detecting the origin position are provided close to each other, and the magnetization vectors of the bias magnets of the magnetic sensors are opposite to each other. Characteristic magnetic encoder device.

A gear formed by radially forming teeth and grooves at a predetermined pitch around the outer periphery of an annular soft magnetic body detects a magnetic passage portion having a small magnetic resistance and a magnetic shielding portion having a large magnetic resistance alternately. A rotating disk to be performed, a magnetic sensor disposed opposite to a predetermined position via the rotating disk and a gap, and a signal processing circuit for processing a signal from the magnetic sensor,
The magnetic encoder device includes a bias magnet disposed to face the magnetic path and the magnetic shield, and a magnetic sensing element disposed between the rotating disk and the bias magnet. At
N (n is an integer of 1 or more) auxiliary magnets are arranged near the magnetic sensor, and the auxiliary magnet has a magnetomotive force of 1 / n of the bias magnet, and magnetizes the bias magnet. A magnetic encoder device having a magnetization vector that is opposite to the vector.

A gear formed by radially forming teeth and grooves at a predetermined pitch around the outer periphery of an annular soft magnetic body detects a magnetic passage portion having a small magnetic resistance and a magnetic shielding portion having a large magnetic resistance alternately. A rotating disk to be performed, a magnetic sensor disposed opposite to a predetermined position via the rotating disk and a gap, and a signal processing circuit for processing a signal from the magnetic sensor,
A magnetic encoder device comprising: a bias magnet disposed so as to face the magnetic path portion and the magnetic shielding portion; and a magnetic sensing element disposed between the rotating disk and the bias magnet. At
The rotating disk has a gear for position detection having teeth and grooves for position detection, a gear for motor pole detection having teeth and grooves for motor magnetic pole detection, and a tooth and groove for origin position detection. And each of the gears is provided along the axial direction,
The magnetic sensors are provided at the positions of the respective gears, and a plurality of magnetic sensors provided at the positions of the magnetic pole detection gears are provided in close proximity to each other, and the magnetization vectors of the bias magnets of the adjacent magnetic sensors are reduced. They are arranged to be opposite to each other,
Magnetic sensors provided at respective positions of the position detection gear and the origin position detection gear are provided close to each other, and magnetization vectors of bias magnets of the magnetic sensor are opposite to each other. Magnetic encoder device.