JP2012251843A - Magnet and magnetic detection device using the magnet - Google Patents

Magnet and magnetic detection device using the magnet Download PDF

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JP2012251843A
JP2012251843A JP2011123986A JP2011123986A JP2012251843A JP 2012251843 A JP2012251843 A JP 2012251843A JP 2011123986 A JP2011123986 A JP 2011123986A JP 2011123986 A JP2011123986 A JP 2011123986A JP 2012251843 A JP2012251843 A JP 2012251843A
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magnet
magnetic
magnetic sensor
pole
detection device
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Hiromi Sato
弘実 佐藤
Tokuo Nakamura
徳男 中村
Hirobumi Okumura
博文 奥村
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Alps Alpine Co Ltd
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Alps Electric Co Ltd
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Priority to KR1020120043828A priority patent/KR101376243B1/en
Priority to CN2012101322319A priority patent/CN102810380A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/02—Permanent magnets [PM]
    • H01F7/0273—Magnetic circuits with PM for magnetic field generation
    • H01F7/0294—Detection, inspection, magnetic treatment
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
    • G01D5/245—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains using a variable number of pulses in a train
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F13/00—Apparatus or processes for magnetising or demagnetising
    • H01F13/003—Methods and devices for magnetising permanent magnets

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  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)
  • Measuring Magnetic Variables (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide a magnet for magnetic detection device that can improve, especially, detection sensitivity and make small an output error in variance of a gap between a magnetic sensor and the magnet, and a magnetic detection device which uses the magnet.SOLUTION: A magnet 13 for magnetic detection device which is arranged so as to have a gap in a height direction with a magnetic sensor is characterized in that a plurality of projections 17 are formed on an opposite surface (first surface 13a), which faces a magnetic detection element 16 constituting the magnetic sensor, at intervals in a direction of relative movement with the magnetic sensor, and the respective projections 17 are divided on the opposite surface each by two into an N pole and an S pole which are alternately magnetized in the direction of relative movement.

Description

本発明は、磁気センサと非接触にて配置され、磁気センサとの対向面に、Ｎ極とＳ極とが前記磁気センサの相対移動方向に交互に着磁されてなる磁石の形状に関する。   The present invention relates to a shape of a magnet which is arranged in a non-contact manner with a magnetic sensor and in which N poles and S poles are alternately magnetized in the relative movement direction of the magnetic sensor on a surface facing the magnetic sensor.

図６（ａ）は、従来における磁気検出装置用の磁石の分解斜視図、図６（ｂ）は、図６（ａ）の磁石Ａ及び磁石Ｂを組み合わせた磁石の斜視図（（ａ）よりもやや大きく図示した）、図６（ｃ）は、図６（ｂ）に示す着磁面を円周方向に沿って切断した磁石と磁気センサとを備える磁気検出装置の部分拡大縦断面図である。   6A is an exploded perspective view of a conventional magnet for a magnetic detection device, and FIG. 6B is a perspective view of a magnet in which the magnet A and the magnet B in FIG. 6A are combined (from FIG. 6A). 6 (c) is a partially enlarged longitudinal sectional view of a magnetic detection device including a magnet and a magnetic sensor obtained by cutting the magnetized surface shown in FIG. 6 (b) along the circumferential direction. is there.

図６（ａ）に示すように例えば、磁石Ａの表面はＮ極に着磁され、磁石Ｂの表面はＳ極に着磁されている。したがって図６（ｂ）に示すように磁石Ａと磁石Ｂとを組み立てた磁石１の表面（磁気センサ２との対向面；着磁面）１ａは、円周方向に沿ってＮ極とＳ極とが交互に並んでいる。   As shown in FIG. 6A, for example, the surface of the magnet A is magnetized to the N pole, and the surface of the magnet B is magnetized to the S pole. Therefore, as shown in FIG. 6B, the surface (opposite surface to the magnetic sensor 2; magnetized surface) 1a of the magnet 1 in which the magnet A and the magnet B are assembled has an N pole and an S pole along the circumferential direction. And are lined up alternately.

図６（ｃ）に示すように、磁気センサ２は、磁石１の表面１ａに対して高さ方向（Ｚ）にギャップＧ0を空けて支持されている。例えば磁石１が回転して、磁気センサ２が磁石１の表面１ａと非接触にて相対移動する。磁気センサ２は、磁石１の表面１ａから生じた磁場Ｍ0を検知し、磁気検出装置では、センサ出力に基づいて回転情報を知ることができる。 As shown in FIG. 6C, the magnetic sensor 2 is supported with a gap G 0 in the height direction (Z) with respect to the surface 1 a of the magnet 1. For example, the magnet 1 rotates and the magnetic sensor 2 moves relative to the surface 1a of the magnet 1 in a non-contact manner. The magnetic sensor 2 detects the magnetic field M 0 generated from the surface 1a of the magnet 1, and the magnetic detection device can know the rotation information based on the sensor output.

図７は、図６に示す磁石の回転角度と磁気センサ２に作用する磁場（磁束密度）との関係を示すシミュレーション結果である。なお横軸の単位はｍｍである。   FIG. 7 is a simulation result showing the relationship between the rotation angle of the magnet shown in FIG. 6 and the magnetic field (magnetic flux density) acting on the magnetic sensor 2. The unit of the horizontal axis is mm.

図７に示すように磁場は、回転角度に対して略ＳＩＮ波を描く。図６（ｃ）のように磁石Ａ，Ｂを二枚重ねると、磁気センサに作用する磁場Ｍ0を、磁石が一枚の構成に比べて大きくできる。また磁場の大きさは、磁石１と磁気センサ２との間のギャップＧ0によって変化する。図７では、図６（ｃ）に示した磁石１と磁気センサ２との間のギャップＧ0を０．５ｍｍ、０．８ｍｍ、１．０ｍｍと変化させて実験を行っている。図７に示すようにギャップＧ0が小さくなれば、磁気センサ２に作用する磁場を大きくできることがわかる。 As shown in FIG. 7, the magnetic field draws a substantially SIN wave with respect to the rotation angle. When two magnets A and B are stacked as shown in FIG. 6C, the magnetic field M 0 acting on the magnetic sensor can be increased as compared with the configuration with one magnet. The magnitude of the magnetic field changes depending on the gap G 0 between the magnet 1 and the magnetic sensor 2. In FIG. 7, the experiment is performed by changing the gap G 0 between the magnet 1 and the magnetic sensor 2 shown in FIG. 6C to 0.5 mm, 0.8 mm, and 1.0 mm. As shown in FIG. 7, it can be seen that if the gap G 0 is reduced, the magnetic field acting on the magnetic sensor 2 can be increased.

図８は、回転角度に対する磁場の波形とＯＮ／ＯＦＦ閾値を示すイメージ図である。ＯＮ／ＯＦＦ閾値は、磁場曲線における最大磁場と最小磁場の間に設定される。図８に示すように、磁気センサ２に作用する磁場は回転角度に対して略ＳＩＮ波となるため、ＯＮ／ＯＦＦ閾値（図示しないが、スレッショルドレベルは高い値（ＯＮ）と低い値（ＯＦＦ）とに設定されている）は、磁場曲線の傾斜領域に設定され、ＯＮ／ＯＦＦの切換が安定しない。例えば磁石を時計方向に回転させたときと反時計方向に回転させたときとで、ＯＮ／ＯＦＦの切換がばらつき、検出感度が低下する問題があった。   FIG. 8 is an image diagram showing a magnetic field waveform and an ON / OFF threshold with respect to the rotation angle. The ON / OFF threshold is set between the maximum magnetic field and the minimum magnetic field in the magnetic field curve. As shown in FIG. 8, since the magnetic field acting on the magnetic sensor 2 becomes a substantially SIN wave with respect to the rotation angle, the ON / OFF threshold (not shown, the threshold level is a high value (ON) and a low value (OFF). Is set in the slope region of the magnetic field curve, and ON / OFF switching is not stable. For example, there is a problem that the ON / OFF switching varies between when the magnet is rotated clockwise and when it is rotated counterclockwise, and detection sensitivity is lowered.

図７，図８に示すように、ギャップＧ0を小さくすれば、磁場曲線の傾斜角度を大きく（急勾配に）できるが、磁場が略ＳＩＮ波の波形ではそれにも限界があった。加えて磁気センサ２と磁石１間のギャップＧ0がばらつくと、ＯＮ／ＯＦＦ閾値での磁場の傾きが変化することに起因して、図８に示すように、ＯＮ／ＯＦＦ点ａ，ｂが変化し、ギャップＧ0のばらつきにより出力誤差が生じる問題があった。 As shown in FIGS. 7 and 8, if the gap G 0 is reduced, the inclination angle of the magnetic field curve can be increased (steeply), but there is a limit to this in the case of a substantially SIN wave waveform. In addition, when the gap G 0 between the magnetic sensor 2 and the magnet 1 varies, the ON / OFF points a and b are changed as shown in FIG. 8 due to the change in the magnetic field gradient at the ON / OFF threshold. There is a problem that an output error occurs due to variation in the gap G 0 .

特許文献１に開示された磁石は、図６に示す磁石１と同様に複数の磁石を組み合わせた構成で、側面がＮ極とＳ極とに交互に着磁されている。特許文献１の構成では上記した従来課題を解決できない。   The magnet disclosed in Patent Document 1 has a configuration in which a plurality of magnets are combined in the same manner as the magnet 1 shown in FIG. 6, and the side surfaces are alternately magnetized into N and S poles. The configuration of Patent Document 1 cannot solve the above-described conventional problem.

また、特許文献２及び特許文献３では、表面に複数の凹凸部が形成された磁石が開示されている。特許文献２に記載された磁石は各凸部がＮ極とＳ極に交互に着磁されている。特許文献２は着磁精度の向上を図る発明であり、上記した従来課題を解決するためのものではない。   Moreover, in patent document 2 and patent document 3, the magnet by which the several uneven | corrugated | grooved part was formed in the surface is disclosed. In the magnet described in Patent Document 2, each convex portion is magnetized alternately in N and S poles. Patent Document 2 is an invention for improving the magnetization accuracy and is not intended to solve the above-described conventional problems.

また特許文献３に記載された磁石は、各凸部がＮ極に、凸部間の各凹部がＳ極に夫々、着磁されている。特許文献３には、Ｎ極とＳ極との間で段差を有するため急峻な磁界が得られるとの記載がある（特許文献３の［００２７］欄参照）。   In the magnet described in Patent Document 3, each convex portion is magnetized to the N pole, and each concave portion between the convex portions is magnetized to the S pole. Patent Document 3 describes that a steep magnetic field can be obtained because there is a step between N and S poles (see [0027] column of Patent Document 3).

しかしながら特許文献３に記載された発明では、磁気センサと磁石間のギャップ変化に対するＯＮ／ＯＦＦ点のばらつきを抑制するための磁石構造に関しては提示されていない。   However, the invention described in Patent Document 3 does not provide a magnet structure for suppressing variations in ON / OFF points with respect to a gap change between the magnetic sensor and the magnet.

特開平８−２３３５０７号公報JP-A-8-233507 特開２０１０−４０９１４号公報JP 2010-40914 A 特開２００４−３１７４５３号公報JP 2004-317453 A

そこで本発明は上記従来の課題を解決するためのものであり、特に、検出感度を向上させることができるとともに、磁気センサと磁石間のギャップのばらつきに対して出力誤差を小さくできる磁気検出装置用の磁石、及び前記磁石を用いた磁気検出装置を提供することを目的とする。   Therefore, the present invention is for solving the above-described conventional problems, and in particular for a magnetic detection device that can improve detection sensitivity and reduce output error with respect to variation in gap between the magnetic sensor and the magnet. An object of the present invention is to provide a magnet and a magnetic detection device using the magnet.

本発明は、磁気センサと高さ方向にギャップを介して配置される磁気検出装置用の磁石において、
前記磁気センサとの対向面に複数の凸部が、前記磁気センサとの相対移動方向に間隔を空けて形成されており、
各凸部が夫々、前記対向面にて前記相対移動方向に交互に着磁されたＮ極とＳ極とにニ分割されていることを特徴とするものである。 The present invention relates to a magnet for a magnetic detection device arranged with a gap in the height direction with a magnetic sensor,
A plurality of convex portions are formed on the surface facing the magnetic sensor at intervals in the direction of relative movement with the magnetic sensor,
Each of the convex portions is divided into two N poles and S poles alternately magnetized in the relative movement direction on the facing surface.

また、本発明における磁気検出装置は、上記の磁石と、前記磁石の前記対向面に高さ方向にギャップを介して配置された磁気センサとを有し、前記磁気センサは前記磁石に対して、前記磁石の各凸部を二分割し交互に着磁された前記Ｎ極と前記Ｓ極との並び方向に相対移動可能に支持されていることを特徴とするものである。   In addition, a magnetic detection device according to the present invention includes the above-described magnet and a magnetic sensor disposed on the facing surface of the magnet via a gap in a height direction, and the magnetic sensor is Each of the convex portions of the magnet is divided into two and is supported so as to be relatively movable in the direction in which the N pole and the S pole are alternately magnetized.

本発明では、各凸部を前記相対移動方向に交互に着磁されるＮ極とＳ極とに二分割した。これにより磁石の形状効果で磁気センサに作用する磁場変化を急峻にでき、検出感度を向上させることができるとともに、磁石と磁気センサ間のギャップ変化に対する出力誤差を小さくできる。   In the present invention, each convex portion is divided into two, an N pole and an S pole, which are alternately magnetized in the relative movement direction. As a result, the magnetic field change acting on the magnetic sensor can be sharpened by the shape effect of the magnet, the detection sensitivity can be improved, and the output error with respect to the gap change between the magnet and the magnetic sensor can be reduced.

本発明によれば、磁気センサに作用する磁場変化を急峻にでき、検出感度を向上させることができるとともに、磁石と磁気センサ間のギャップ変化に対する出力誤差を小さくできる。   According to the present invention, a change in magnetic field acting on the magnetic sensor can be sharpened, the detection sensitivity can be improved, and an output error with respect to a gap change between the magnet and the magnetic sensor can be reduced.

本実施形態の磁気検出装置の斜視図、The perspective view of the magnetic detection apparatus of this embodiment, 図１に示す磁気検出装置の分解斜視図、1 is an exploded perspective view of the magnetic detection device shown in FIG. 本実施形態における磁石の斜視図、The perspective view of the magnet in this embodiment, 図３に示す磁石と磁気センサを構成する磁気検出素子とを示す側面図、The side view which shows the magnet shown in FIG. 3, and the magnetic detection element which comprises a magnetic sensor, （ａ）は、本実施例における磁気検出装置を構成する磁石の回転角度と磁気検出素子に作用する磁場（磁束密度）との関係を示すグラフであり、（ｂ）は、磁石の回転角度とセンサ出力との関係を示すグラフ、(A) is a graph which shows the relationship between the rotation angle of the magnet which comprises the magnetic detection apparatus in a present Example, and the magnetic field (magnetic flux density) which acts on a magnetic detection element, (b) is the rotation angle of a magnet, Graph showing the relationship with sensor output, （ａ）は、従来における磁気検出装置用の磁石の分解斜視図、（ｂ）は、（ａ）の磁石Ａ及び磁石Ｂを組み合わせた磁石の斜視図（（ａ）よりもやや大きく図示した）、（ｃ）は、（ｂ）に示す着磁面を円周方向に沿って切断した磁石と磁気センサとを備える磁気検出装置の部分拡大縦断面図、(A) is an exploded perspective view of a conventional magnet for a magnetic detection device, (b) is a perspective view of a magnet combining the magnet A and the magnet B of (a) (shown slightly larger than (a)) (C) is a partially enlarged longitudinal sectional view of a magnetic detection device including a magnet and a magnetic sensor obtained by cutting the magnetized surface shown in (b) along the circumferential direction; 磁石の回転角度と磁気センサに作用する磁場（磁束密度）との関係を示すグラフ、A graph showing the relationship between the rotation angle of the magnet and the magnetic field (magnetic flux density) acting on the magnetic sensor, 磁石の回転角度と磁気センサに作用する磁場及びＯＮ／ＯＦＦ閾値との関係を示すイメージ図。The image figure which shows the relationship between the rotation angle of a magnet, the magnetic field which acts on a magnetic sensor, and an ON / OFF threshold value.

図１は、本実施形態の磁気検出装置の斜視図であり、図２は、図１に示す磁気検出装置の分解斜視図であり、図３は、本実施形態における磁石の斜視図であり、図４は、図３に示す磁石と磁気センサを構成する磁気検出素子とを示す側面図である。   FIG. 1 is a perspective view of the magnetic detection device of the present embodiment, FIG. 2 is an exploded perspective view of the magnetic detection device shown in FIG. 1, and FIG. 3 is a perspective view of a magnet in the present embodiment. FIG. 4 is a side view showing the magnet shown in FIG. 3 and a magnetic detection element constituting the magnetic sensor.

図１，図２に示す磁気検出装置１０は、カバー１１、シャフト１２、磁石１３、磁気センサ１４及びケース１５等を有して構成される。このうち、磁石１３と磁気センサ１４は磁気検出装置１０として必須部品であるが、それ以外の構成については特に限定しない。すなわち本実施形態の磁気検出装置１０は、車載用、電子機器用等、使用用途を限定するものでなく、各使用用途に合わせて構成部品が決められる。   1 and 2 includes a cover 11, a shaft 12, a magnet 13, a magnetic sensor 14, a case 15, and the like. Among these, the magnet 13 and the magnetic sensor 14 are indispensable parts as the magnetic detection device 10, but other configurations are not particularly limited. That is, the magnetic detection device 10 according to the present embodiment is not limited to usage applications such as in-vehicle use and electronic equipment, and components are determined according to each use application.

図３に示すように磁石１３は、リング状に形成され、高さ方向にて対向する第１面１３ａと、第２面１３ｂ、及び第１面１３ａと第２面１３ｂ間を繋ぐ外側面１３ｃ及び内側面１３ｄと、を備える。図４に示すように、磁気センサ１４を構成する磁気検出素子１６は磁石１３と高さ方向（Ｚ）にてギャップＧ1を有して対向する。ここでいうギャップＧ１とは、図４に示すように磁気検出素子１６と磁石１３を構成する凸部１７の頂面１７ａとの間の間隔を指す。 As shown in FIG. 3, the magnet 13 is formed in a ring shape and is opposed to the first surface 13a, the second surface 13b, and the outer surface 13c connecting the first surface 13a and the second surface 13b. And an inner side surface 13d. As shown in FIG. 4, the magnetic detection element 16 constituting the magnetic sensor 14 faces the magnet 13 with a gap G 1 in the height direction (Z). The gap G <b> 1 here refers to a distance between the magnetic detection element 16 and the top surface 17 a of the convex portion 17 constituting the magnet 13 as shown in FIG. 4.

図３、図４に示すように第１面１３ａには円周方向に沿って複数の凸部１７が間隔を空けて形成されている。各凸部１７は、図３に示すように、磁石１３の外側面１３ｃから内側面１３ｄにまで至って形成される。図１に示す実施形態では、凸部１７は、磁石１３の全周でなく一部にのみ形成されているが、使用用途によって凸部１７を磁石１３のどの領域まで形成するか決めることが出来る。   As shown in FIGS. 3 and 4, a plurality of convex portions 17 are formed on the first surface 13 a at intervals along the circumferential direction. As shown in FIG. 3, each convex portion 17 is formed from the outer side surface 13 c to the inner side surface 13 d of the magnet 13. In the embodiment shown in FIG. 1, the convex portion 17 is formed only on a part rather than the entire circumference of the magnet 13, but it is possible to determine to which region of the magnet 13 the convex portion 17 is formed depending on the use application. .

図４に示すように、凸部１７は高さ寸法Ｈ１を備える。高さ寸法Ｈ１は、１．０〜１．５ｍｍ程度である。図４に示すように凸部１７の円周方向にて対向する壁面１７ｂ，１７ｃは高さ方向（Ｚ）に平行な垂直面で形成されているが多少、傾きがあってもよい。ただし垂直面としたほうが好ましい。   As shown in FIG. 4, the convex part 17 is provided with the height dimension H1. The height dimension H1 is about 1.0 to 1.5 mm. As shown in FIG. 4, the wall surfaces 17 b and 17 c opposed to each other in the circumferential direction of the convex portion 17 are formed as vertical surfaces parallel to the height direction (Z), but may be slightly inclined. However, the vertical plane is preferred.

図３，図４に示すように、各凸部１７，１７の間は、前記凸部１７よりも薄い薄肉部１８を構成している。すなわち円周方向に沿って凸部１７と薄肉部１８とが交互に形成されている。図４に示すように、凸部１７の円周方向への幅寸法Ｔ１は、各凸部１７において略一定である。幅寸法Ｔ1は、１．５ｍｍ程度である。また、薄肉部１８の円周方向への幅寸法Ｔ２は、各薄肉部１８において略一定である。幅寸法Ｔ２は、３〜４ｍｍ程度である。また、薄肉部１８の厚さ寸法Ｈ２は、１．０〜１．５ｍｍ程度である。また磁石１３の内径は、１５ｍｍ程度、磁石１３の外径は３０ｍｍ程度に設定することができる。   As shown in FIGS. 3 and 4, a thin portion 18 that is thinner than the convex portion 17 is formed between the convex portions 17 and 17. That is, the convex portions 17 and the thin portions 18 are alternately formed along the circumferential direction. As shown in FIG. 4, the width dimension T <b> 1 of the convex portion 17 in the circumferential direction is substantially constant in each convex portion 17. The width dimension T1 is about 1.5 mm. Further, the width dimension T <b> 2 in the circumferential direction of the thin portion 18 is substantially constant in each thin portion 18. The width dimension T2 is about 3 to 4 mm. Moreover, the thickness dimension H2 of the thin part 18 is about 1.0-1.5 mm. The inner diameter of the magnet 13 can be set to about 15 mm, and the outer diameter of the magnet 13 can be set to about 30 mm.

図３，図４に示す凸部１７と薄肉部１８とが交互に形成された円周領域の第１面１３ａが、磁気検出素子１６と対向する対向面である。磁石１３あるいは磁気センサ１４の少なくとも一方が回転可能に支持されている。図１，図２に示す実施形態では、磁石１３が回転可能に支持されており、磁気センサ１４が固定されている。磁石１３が回転すると磁気センサ１４は、磁石１３と非接触状態を保ちながら磁石１３の円周方向に沿って相対移動する。   The first surface 13a of the circumferential region in which the convex portions 17 and the thin portions 18 shown in FIGS. 3 and 4 are alternately formed is a facing surface that faces the magnetic detection element 16. At least one of the magnet 13 or the magnetic sensor 14 is rotatably supported. In the embodiment shown in FIGS. 1 and 2, the magnet 13 is rotatably supported, and the magnetic sensor 14 is fixed. When the magnet 13 rotates, the magnetic sensor 14 relatively moves along the circumferential direction of the magnet 13 while maintaining a non-contact state with the magnet 13.

図３，図４に示す磁石１３は、凸部１７と薄肉部１８とが交互に形成された円周領域が、Ｎ極とＳ極とに磁気センサ１４の相対移動方向に沿って交互に着磁されたアキシャル着磁磁石である。各磁極幅Ｔ３は略一定である。   The magnet 13 shown in FIGS. 3 and 4 has circumferential regions in which convex portions 17 and thin portions 18 are alternately formed, which are alternately attached to the north and south poles along the relative movement direction of the magnetic sensor 14. It is a magnetized axially magnetized magnet. Each magnetic pole width T3 is substantially constant.

磁気センサ１４を構成する磁気検出素子１６は、相対移動により、磁石１３のＮ極からＳ極にかけて生じる磁場を受けて電気特性が変化する。前記磁気検出素子１６の電気特性変化に基づいて回転状態（回転角度や回転方向）を知ることができる。図２に示すように磁気センサ１４には複数の磁気検出素子１６が設けられている。このうちの一つの磁気検出素子１６が、図３，図４に示す磁石１３の凸部１７と薄肉部１８との円周領域と非接触で対向している。残りの磁気検出素子１６は、凸部１７と薄肉部１８との円周領域以外の着磁領域（図示しない）にて非接触で対向している。そして各磁気検出素子１６の検出信号（ＯＮ／ＯＦＦ信号）に基づいて、回転状態を検知することが出来る。   The magnetic detection element 16 constituting the magnetic sensor 14 receives a magnetic field generated from the N pole to the S pole of the magnet 13 due to relative movement and changes its electrical characteristics. Based on the change in electrical characteristics of the magnetic detection element 16, the rotation state (rotation angle and direction) can be known. As shown in FIG. 2, the magnetic sensor 14 is provided with a plurality of magnetic detection elements 16. One of the magnetic detection elements 16 is opposed to the circumferential region of the convex portion 17 and the thin portion 18 of the magnet 13 shown in FIGS. 3 and 4 in a non-contact manner. The remaining magnetic detection elements 16 are opposed to each other in a non-contact manner in a magnetized region (not shown) other than the circumferential region between the convex portion 17 and the thin portion 18. Based on the detection signal (ON / OFF signal) of each magnetic detection element 16, the rotation state can be detected.

なお磁気検出素子１６はホール素子、磁気抵抗効果素子（ＧＭＲ素子）等、特に限定するものでない。   The magnetic detection element 16 is not particularly limited, such as a Hall element or a magnetoresistive effect element (GMR element).

図３，図４に示すように本実施形態では、各凸部１７が夫々、相対移動方向（円周方向）に交互に着磁されたＮ極とＳ極とに二分割されている。また図３，図４に示すように各薄肉部１８が夫々、一方の凸部１７のＮ極から連続するＮ極と、他方の凸部１７のＳ極から連続するＳ極とに二分割されている。各凸部１７及び薄肉部１８は、夫々、円周方向のほぼ中央にてＮ極とＳ極とに二分されている。   As shown in FIGS. 3 and 4, in the present embodiment, each convex portion 17 is divided into two, an N pole and an S pole, which are alternately magnetized in the relative movement direction (circumferential direction). Further, as shown in FIGS. 3 and 4, each thin portion 18 is divided into an N pole continuous from the N pole of one convex portion 17 and an S pole continuous from the S pole of the other convex portion 17. ing. Each convex part 17 and the thin part 18 are each divided into an N pole and an S pole at substantially the center in the circumferential direction.

図５（ａ）は、磁石１３の回転角度と磁気検出素子１６に作用する磁場（磁束密度）との関係を示すシミュレーション結果である。実験は、磁気検出素子１６と磁石１３間のギャップＧ1を０．８ｍｍ、１．０ｍｍ、１．２ｍｍに変化させて行った。なお、磁石１３の内径を、１２．５ｍｍ、外径を３０ｍｍ、凸部１７の高さ寸法Ｈ１を１．５ｍｍ、凸部１７の幅寸法Ｔ1を、１．５ｍｍ、薄肉部１８の幅寸法Ｔ２を３．５ｍｍとした。図５（ａ）に示すＯＮ／ＯＦＦ閾値（スレッショルドレベル）は、磁気センサ１４にて設定される。スレッショルドレベルは高い値（ＯＮ）と低い値（ＯＦＦ）を備える。図５（ｂ）は、磁石１３の回転角度とセンサ出力との関係を示している。磁場を受けて磁気検出素子１６のセンサ出力は図５（ｂ）のような矩形波となり、高いスレッショルドレベルを超える磁場を受けるとＯＮ信号を出力し、低いスレッショルドレベルを下回る磁場を受けるとＯＦＦ信号を出力する。 FIG. 5A is a simulation result showing the relationship between the rotation angle of the magnet 13 and the magnetic field (magnetic flux density) acting on the magnetic detection element 16. The experiment was performed by changing the gap G 1 between the magnetic detection element 16 and the magnet 13 to 0.8 mm, 1.0 mm, and 1.2 mm. The inner diameter of the magnet 13 is 12.5 mm, the outer diameter is 30 mm, the height dimension H1 of the convex part 17 is 1.5 mm, the width dimension T1 of the convex part 17 is 1.5 mm, and the width dimension T2 of the thin part 18. Was 3.5 mm. The ON / OFF threshold (threshold level) shown in FIG. 5A is set by the magnetic sensor 14. The threshold level has a high value (ON) and a low value (OFF). FIG. 5B shows the relationship between the rotation angle of the magnet 13 and the sensor output. Upon receiving a magnetic field, the sensor output of the magnetic detection element 16 becomes a rectangular wave as shown in FIG. 5B. When a magnetic field exceeding a high threshold level is received, an ON signal is output, and when receiving a magnetic field below a low threshold level, an OFF signal is output. Is output.

図５（ａ）に示すように、本実施形態では図７の従来例に比べて磁場が急峻に変化しており、従来のＳＩＮ波とは異なる波形となることがわかった。またギャップＧ1が変わると、磁場の大きさは変化するものの、最小磁場（最大磁場）から最大磁場（最小磁場）へ至るまでの磁場曲線の傾きはギャップＧ1に係らずほぼ同じとなることがわかった。図５（ａ）に示す磁場の波形は、磁石１３の形状効果に起因する。すなわち、Ｎ極とＳ極間に形成される磁場は、高さ方向（Ｚ）に長く形成された凸部１７をＮ極とＳ極とに二分したことにより高さ方向（Ｚ）に略平行に生じやすくなっている。また凸部１７と同様に薄肉部１８もＮ極とＳ極とに二分して着磁することで、図５（ａ）に示すように磁場が落ち込む底部を略平坦にでき、図５（ａ）に示す波形を得ることが可能となっている。 As shown in FIG. 5A, it has been found that in this embodiment, the magnetic field changes sharply as compared with the conventional example of FIG. 7, resulting in a waveform different from the conventional SIN wave. When the gap G 1 changes, the magnitude of the magnetic field changes, but the gradient of the magnetic field curve from the minimum magnetic field (maximum magnetic field) to the maximum magnetic field (minimum magnetic field) is almost the same regardless of the gap G 1. I understood. The magnetic field waveform shown in FIG. 5A is due to the shape effect of the magnet 13. That is, the magnetic field formed between the N pole and the S pole is substantially parallel to the height direction (Z) by dividing the convex portion 17 formed long in the height direction (Z) into the N pole and the S pole. It is easy to occur. Similarly to the convex part 17, the thin part 18 is also divided into the N pole and the S pole and magnetized, whereby the bottom where the magnetic field falls can be made substantially flat as shown in FIG. ) Can be obtained.

図５（ａ）に示すようにギャップＧ1が１．２ｍｍ程度まで大きくなり磁場の大きさが小さくなっても、磁場曲線内に適切にＯＮ／ＯＦＦ閾値の設定が可能な程度の磁場を確保でき、図６の従来のように複数枚の磁石を組み合わせて磁場を大きくしなくても検出不能になることはない。実験ではギャップＧ1を０．８ｍｍ〜１．２ｍｍに設定したが、もう少しギャップＧ1が大きくなっても磁気検出は可能である。また磁場曲線の傾きはギャップＧ1が変わってもほぼ同じであるため、図５（ｂ）のように、センサ出力は各ギャップＧ1に対してほぼ同じとなる。図５（ｂ）に示す幅Ｔ４がギャップＧ1の相違に基づくオン／オフ点のばらつきになるが、この幅Ｔ４を本実施形態では従来に比べて十分に小さくすることが可能である。 Figure 5 also gap G 1 as shown in (a) becomes smaller the size of the larger becomes the magnetic field to about 1.2 mm, ensuring a field of degree properly settable in ON / OFF threshold in a magnetic field curve As in the conventional case of FIG. 6, detection does not become impossible even if a plurality of magnets are combined to increase the magnetic field. In the experiment, the gap G 1 was set to 0.8 mm to 1.2 mm, but magnetic detection is possible even if the gap G 1 becomes a little larger. Since the gradient of the magnetic field curve is substantially the same even when the gap G 1 changes, the sensor output is substantially the same for each gap G 1 as shown in FIG. 5B. Width T4 shown in FIG. 5 (b) but is the variation of the on / off point based on the difference in the gap G 1, in this embodiment the width T4 can be sufficiently small as compared with the prior art.

以上のように本実施形態では磁石１３の形状効果で磁場変化を急峻にでき、検出感度を向上させることができるとともに、ギャップＧ1変化に対する出力誤差を小さくすることが可能である。よって本実施形態では、磁石１３と磁気センサ１４との取り付け誤差が比較的大きくなっても、出力誤差を小さくすることが可能である。 In the present embodiment as described above can be steep magnetic field changes in the shape effect of the magnet 13, it is possible to improve the detection sensitivity, it is possible to reduce the output error with respect to the gap G 1 changes. Therefore, in this embodiment, even if the attachment error between the magnet 13 and the magnetic sensor 14 becomes relatively large, the output error can be reduced.

また磁気センサが磁石に対して相対直線移動する形態にも本実施形態を適用可能である。   The present embodiment can also be applied to a form in which the magnetic sensor moves relatively linearly with respect to the magnet.

１０ 磁気検出装置
１３ 磁石
１４ 磁気センサ
１６ 磁気検出素子
１７ 凸部
１８ 薄肉部 DESCRIPTION OF SYMBOLS 10 Magnetic detection apparatus 13 Magnet 14 Magnetic sensor 16 Magnetic detection element 17 Convex part 18 Thin part

Claims (2)

磁気センサと高さ方向にギャップを介して配置される磁気検出装置用の磁石において、
前記磁気センサとの対向面に複数の凸部が、前記磁気センサとの相対移動方向に間隔を空けて形成されており、
各凸部が夫々、前記対向面にて前記相対移動方向に交互に着磁されたＮ極とＳ極とにニ分割されていることを特徴とする磁気検出装置用の磁石。 In a magnet for a magnetic sensor arranged with a gap in the height direction with a magnetic sensor,
A plurality of convex portions are formed on the surface facing the magnetic sensor at intervals in the direction of relative movement with the magnetic sensor,
A magnet for a magnetic detection device, wherein each convex portion is divided into two, an N pole and an S pole, which are alternately magnetized in the relative movement direction on the facing surface. 請求項１に記載された磁石と、前記磁石の前記対向面に高さ方向にギャップを介して配置された磁気センサとを有し、前記磁気センサは前記磁石に対して、前記磁石の各凸部を二分割し交互に着磁された前記Ｎ極と前記Ｓ極との並び方向に相対移動可能に支持されていることを特徴とする磁気検出装置。   A magnet according to claim 1, and a magnetic sensor disposed on the facing surface of the magnet via a gap in a height direction, wherein the magnetic sensor protrudes from the magnet with respect to each protrusion of the magnet. A magnetic detection device, wherein the magnetic detection device is supported so as to be relatively movable in the arrangement direction of the N pole and the S pole, which are divided into two parts and alternately magnetized.
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JP2017227567A (en) * 2016-06-23 2017-12-28 ミネベアミツミ株式会社 Rotation device

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