JPH0690045B2 - Index signal sensor - Google Patents
Index signal sensorInfo
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- JPH0690045B2 JPH0690045B2 JP61247622A JP24762286A JPH0690045B2 JP H0690045 B2 JPH0690045 B2 JP H0690045B2 JP 61247622 A JP61247622 A JP 61247622A JP 24762286 A JP24762286 A JP 24762286A JP H0690045 B2 JPH0690045 B2 JP H0690045B2
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- Prior art keywords
- elements
- index signal
- magnetoresistive effect
- magnetized
- detection
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- Measuring Magnetic Variables (AREA)
- Hall/Mr Elements (AREA)
- Control Of Velocity Or Acceleration (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、磁気式の位置検出器、特に、強磁性磁気抵抗
効果素子（以下、MR素子という）を用いたインデツクス
信号センサに関する。The present invention relates to a magnetic position detector, and more particularly to an index signal sensor using a ferromagnetic magnetoresistive effect element (hereinafter referred to as MR element).
従来、モータの速度制御，位相制御を行うために、モー
タの回転軸に周波数発生器（FG）が設けられ、モータの
回転速度に比例した周波数のFG信号と、モータの回転位
相を表すインデツクス信号とが得られるようにしてい
る。周波数発生器には光学式と磁気式とがあるが、寸法
精度や構造の点から専ら磁気式のものが使用され、しか
も、MP素子を用いることにより、光学式と同程度の性能
が得られる。Conventionally, a frequency generator (FG) is provided on the rotating shaft of the motor to control the speed and phase of the motor, and an FG signal of a frequency proportional to the rotating speed of the motor and an index signal indicating the rotating phase of the motor are provided. I am trying to obtain There are optical type and magnetic type in the frequency generator, but the magnetic type is used exclusively from the point of view of dimensional accuracy and structure. Moreover, by using the MP element, the same performance as the optical type can be obtained. .
かかる磁気式の周波数発生器の一例が、たとえば、“Na
tional Technical Report"1984年12月、pp.33-34に開示
されている。これによると、モータの回転軸に取りつけ
られた磁気ドラムの外周に一周にわたつてフエライト粉
末などが充填されてなる帯状のプラスチツク磁石が２本
平行に設けられ、その一方は等長に分割されて着磁領域
とし、これら着磁領域は順次１つ毎に磁化方向が異なる
ように着磁され、このプラスチツク磁石をMR素子で走査
することにより、FG信号が検出される。また、他方のプ
ラスチツク磁石において、その一部に所定の長さの着磁
領域が設けられ、これを別のMR素子で走査することによ
り、この着磁領域を検出してモータの１回転毎に１回イ
ンデツクス信号が得られる。An example of such a magnetic frequency generator is, for example, "Na
tional Technical Report "December 1984, pp.33-34. According to this, a belt-shaped strip formed by filling the outer circumference of a magnetic drum attached to the rotating shaft of a motor with ferrite powder, etc. Two plastic magnets are provided in parallel, one of which is divided into equal lengths to form a magnetized region, and these magnetized regions are sequentially magnetized so that the magnetization directions are different from each other. The FG signal is detected by scanning with the element, and the other plastic magnet is provided with a magnetized region of a predetermined length in a part thereof, and by scanning this with another MR element, By detecting this magnetized region, an index signal is obtained once for each rotation of the motor.
上記のような従来技術において、インデツクス信号を用
いてモータの位相制御を行う場合、この位相制御の基準
タイミングはインデツクス信号の立上りエツジから検出
される。In the conventional technique as described above, when the phase control of the motor is performed using the index signal, the reference timing of this phase control is detected from the rising edge of the index signal.
ところで、上記のプラスチツク磁石からその一部に設け
られた着磁領域を検出してインデツクス信号を再生する
場合、MR素子は有限の幅を有しているために、得られる
インデツクス信号の立上りエツジは傾斜したものとな
る。これを改善するために、MR素子を薄膜状としてその
幅を極めて狭くすることが考えられるが、これでもやは
りその幅は有限であるし、しかも、幅が狭くなつたこと
によつてMR素子の検出出力が低下してS/Nが劣化すると
いう問題が生ずる。By the way, when the index signal is reproduced by detecting a magnetized area provided in a part of the plastic magnet, the MR element has a finite width, and thus the rising edge of the obtained index signal is It will be inclined. In order to improve this, it is conceivable to make the MR element into a thin film and make its width extremely narrow, but even this still has a finite width, and the fact that the width has become narrow There is a problem that the detection output decreases and the S / N deteriorates.
さらに、上記のように一部だけに着磁領域が設けられた
プラスチツク磁石の場合には、この着磁領域からの磁界
はプラスチツク磁石の長手方向着磁領域外にも広がつた
ものとなり（すなわち、もれ磁界が生じ）、このため
に、MR素子は着磁領域に対向する以前からこの着磁領域
からの磁界を検出することになり、この結果、得られる
インデツクス信号は、第６図に示すように、非常に裾広
がりの立上り傾斜が緩やかな波形となる。したがつて、
このような波形のインデツクス信号からMR素子が着磁領
域の境界を通過した時点を検出することは難しく、特
に、MR素子の検出出力が低いときには、境界通過時点の
検出のための調整に非常に手間がかかることになる。Further, in the case of a plastic magnet having a magnetized region provided only in a part as described above, the magnetic field from this magnetized region is also spread outside the longitudinal magnetized region of the plastic magnet (that is, , A leakage magnetic field is generated). Therefore, the MR element detects the magnetic field from the magnetized area before it faces the magnetized area. As a result, the obtained index signal is shown in FIG. As shown in the figure, the waveform has a very gradual swelling rising slope. Therefore,
It is difficult to detect the time when the MR element passes the boundary of the magnetized area from the index signal of such a waveform, and especially when the detection output of the MR element is low, it is very necessary to make adjustments for detecting the time when the boundary is passed. It will be troublesome.
本発明の目的は、かかる問題点を解消し、高いS/Nで立
上りが急峻となり、着磁領域の境界を正確に検出できる
インデツクス信号を得ることができるようにしたインデ
ツクス信号センサを提供するにある。An object of the present invention is to solve the above problems, to provide an index signal sensor capable of obtaining an index signal capable of accurately detecting the boundary of the magnetized region with a sharp rise at a high S / N. is there.
上記目的を達成するために、本発明は、プラスチツク磁
石の長手方向に互いに平行に配置した４個のMR素子でも
つて検出部とし、第1,第２のMR素子は互いに近接し、第
３のMR素子は第１のMR素子から、また、第４のMR素子は
第２のMR素子から夫々プラスチツク磁石の着磁領域の長
さ分だけ隔たつているようにする。In order to achieve the above-mentioned object, the present invention provides a detection unit with four MR elements arranged in parallel with each other in the longitudinal direction of the plastic magnet, and the first and second MR elements are close to each other and the third MR element is provided. The MR element is separated from the first MR element, and the fourth MR element is separated from the second MR element by the length of the magnetized region of the plastic magnet.
第1,第２のMR素子の検出出力はほとんど同相であり、第
3,第４のMR素子の検出出力は互いに着磁領域の長さの２
倍に相当する位相だけずれるとともに、第1,第２のMR素
子の検出出力よりも着磁領域の長さに相当する位相だけ
ずれている。The detection outputs of the first and second MR elements are almost in phase,
3, the detection output of the 4th MR element is 2 of the length of the magnetized area.
Not only is the phase shifted by a factor of two, but it is also shifted by a phase corresponding to the length of the magnetized region from the detection outputs of the first and second MR elements.
インデツクス信号は、これら第１〜第４のMR素子の検出
出力を合成処理することにより、すなわち、第1,第２の
MR素子の検出出力を加算し、さらに、これに第3,第４の
MR素子の検出出力を減算することにより、得ることがで
きるが、各MR素子が上記のように配置されていることか
ら、このインデツクス信号は、１個のMR素子を用いたと
きに得られるインデツクス信号のほぼ２倍の振幅となつ
てS/Nが高くなり、また、第3,第４のMR素子の検出出力
による減算によつて波形の裾部が抑圧されて急峻なエツ
ジの信号となる。The index signal is obtained by combining the detection outputs of these first to fourth MR elements, that is, the first and second MR elements.
Add the detection output of the MR element, and then add the 3rd and 4th
This can be obtained by subtracting the detection output of the MR element, but since each MR element is arranged as described above, this index signal is the index signal obtained when one MR element is used. The S / N becomes higher because the amplitude is almost twice that of the signal, and the skirt of the waveform is suppressed by subtraction by the detection output of the third and fourth MR elements, resulting in a sharp edge signal. .
以下、本発明の実施例を図面によつて説明する。 Embodiments of the present invention will be described below with reference to the drawings.
第１図は本発明によるインデツクス信号センサの一実施
例を示す要部構成図であつて、１〜４はMR素子、５はプ
ラスチツク磁石、６は無着磁領域、７は着磁領域、7A,7
Bは境界である。FIG. 1 is a main part configuration diagram showing an embodiment of an index signal sensor according to the present invention, in which 1 to 4 are MR elements, 5 is a plastic magnet, 6 is a non-magnetized region, 7 is a magnetized region, and 7A. , 7
B is the boundary.
同図において、たとえば回転体の周面一周にわたつて設
けられた帯状のプラスチツク磁石５の一部に所定の長さ
Ｐの着磁領域７が設けられており、かかるプラスチツク
磁石５に対向してこの実施例の検出部を構成するMP素子
１〜４が配置される。これらMR素子１〜４はプラスチツ
ク磁石５に沿つて互いに平行に配置されており、回転体
が回転してプラスチツク磁石５を走査するとき、着磁領
域７による磁界（具体的にはその水平成分）を同程度に
検出するようにしている。In the figure, for example, a magnetized region 7 having a predetermined length P is provided in a part of a belt-like plastic magnet 5 provided over the entire circumference of the rotating body, and is opposed to the plastic magnet 5. MP elements 1 to 4 constituting the detection unit of this embodiment are arranged. These MR elements 1 to 4 are arranged parallel to each other along the plastic magnet 5, and when the rotating body rotates and scans the plastic magnet 5, the magnetic field (specifically, the horizontal component) by the magnetized area 7 is generated. Are detected to the same degree.
ここで、MR素子1,2は互いに近接して配置されており、M
R素子３はMR素子２からMR素子１とは反対側に着磁領域
７の長さＰだけ隔てて配置され、MR素子４はMR素子１か
らMR素子２とは反対側に同じ長さＰだけ隔てて配置され
ている。Here, MR elements 1 and 2 are arranged close to each other, and M
The R element 3 is arranged on the opposite side from the MR element 2 by the length P of the magnetized region 7, and the MR element 4 is the same length P on the opposite side from the MR element 1 to the MR element 2. It is only separated.
以上のように配置されたMR素子１〜４に対してプラスチ
ツク磁石５が矢印方向に移動しているものとすると、MR
素子4,1,2,3の順で着磁領域７からの磁界を抵抗値の変
化として検出するが、MR素子1,2は互いに近接している
から、これらの検出出力はほとんど同相である。これに
対して、MR素子1,2の検出出力の位相を基準とすると、M
R素子３の検出出力は着磁領域７の長さＰを通過するに
要する時間tpだけ遅れ、MR素子４の検出出力は逆に時間
tpだけ進むことになる。If the plastic magnet 5 is moving in the direction of the arrow with respect to the MR elements 1 to 4 arranged as described above, the MR
The magnetic field from the magnetized region 7 is detected as a change in resistance value in the order of the elements 4, 1, 2 and 3, but since the MR elements 1 and 2 are close to each other, their detection outputs are almost in phase. . On the other hand, if the phase of the detection output of MR elements 1 and 2 is used as the reference, M
The detection output of the R element 3 is delayed by the time tp required to pass the length P of the magnetized region 7, and the detection output of the MR element 4 is conversely timed.
Only tp will be advanced.
また、先にも説明したように、着磁領域７による磁界は
無着磁領域６にも裾状に広がつており、MR素子１〜４は
着磁領域７の境界7Aの直前の無着磁領域６を走査してい
るときから磁界を検出し始め、また、着磁領域７の境界
7Bの直後の無着磁領域６を走査し始めても磁界を検出し
ている。しかし、これらMR素子１〜４は着磁領域の中央
部に対向しているときに最大の検出結果を出力する。し
たがつて、MR素子1,2の検出出力は、第１図に示すよう
に、着磁領域７の中央部に対向しているときに最大とな
り、MR素子4,3の検出出力も、夫々第２図，第３図に示
すように、着磁領域７の中央部に対向しているときに最
大となる。Further, as described above, the magnetic field generated by the magnetized region 7 also spreads like a skirt in the non-magnetized region 6, and the MR elements 1 to 4 are not magnetized immediately before the boundary 7A of the magnetized region 7. The magnetic field begins to be detected while scanning the magnetic region 6, and the boundary of the magnetized region 7
The magnetic field is detected even when the non-magnetized region 6 immediately after 7B is started to be scanned. However, these MR elements 1 to 4 output the maximum detection result when facing the central portion of the magnetized region. Therefore, as shown in FIG. 1, the detection outputs of the MR elements 1 and 2 become maximum when facing the central portion of the magnetized region 7, and the detection outputs of the MR elements 4 and 3 are also respectively. As shown in FIGS. 2 and 3, the maximum value is obtained when facing the central portion of the magnetized region 7.
それら、これらMR素子の検出出力は、第４図（ａ）〜
（ｄ）に示すように、裾が広がつて立上り、立下りエツ
ジが非常に緩やかな波形となる。なお、第４図（ａ）は
MR素子４の，同図（ｂ）はMR素子１の，同図（ｃ）はMR
素子２の，同図（ｄ）はMR素子３の夫々検出出力波形を
示しており、tpは、上記のように、MR素子１〜４が着磁
領域７の長さｐだけ通過するに要する時間を表す。The detection outputs of these MR elements are shown in FIG.
As shown in (d), the hem is wide and rises, and the falling edge has a very gentle waveform. In addition, FIG. 4 (a) is
The MR element 4 is the MR element 1, the figure (b) is the MR element 1, and the figure (c) is the MR.
The same figure (d) of the element 2 shows the detection output waveforms of the MR element 3, respectively, and tp is required for the MR elements 1 to 4 to pass by the length p of the magnetized region 7, as described above. Represents time.
インデツクス信号はこれらMR素子１〜４の検出出力を次
のように合成することによつて得られる。すなわち、MR
素子1,2の検出出力（第４図（ｂ），（ｃ））は互いに
加算され、これにMR素子3,4の検出出力（第４図
（ｄ），（ａ））が加算される。この結果、得られるイ
ンデツクス信号の波形は、第４図（ｅ）に示すように、
振幅がMR素子１〜４各々から得られる検出出力のほぼ２
倍となり、裾部分が逆極性となつて立上り、立下りエツ
ジが急峻になる。The index signal is obtained by synthesizing the detection outputs of these MR elements 1 to 4 as follows. Ie MR
The detection outputs of the elements 1 and 2 (FIGS. 4 (b) and (c)) are added to each other, and the detection outputs of the MR elements 3 and 4 (FIGs. 4 (d) and (a)) are added to this. . As a result, the waveform of the obtained index signal is, as shown in FIG.
The amplitude is almost 2 of the detection output obtained from each of MR elements 1 to 4.
It doubles, and the hem part has a reverse polarity and rises, and the falling edge becomes steep.
第５図は合成回路の一具体例を示す回路図であつて、8,
9は出力端子であり、第１図に対応する部分には同一符
号をつけている。FIG. 5 is a circuit diagram showing a concrete example of the synthesizing circuit.
Reference numeral 9 is an output terminal, and the parts corresponding to those in FIG.
この具体例は、MR素子１〜４の結線方法を特定すること
により、これらの検出出力を上記のように合成するもの
である。In this specific example, by specifying the connection method of the MR elements 1 to 4, these detection outputs are combined as described above.
第５図において、電源電圧Vccが印加される電源端子と
接地端子との間に、MR素子2,4が直列に接続され、同様
にして、MR素子3,1も直列に接続されている。そして、M
R素子2,4の接続点に出力端子８を設け、また、MR素子3,
1の接続点に出力端子９を設け、これら出力端子8,9間の
電圧をインデツクス信号として取り出す。In FIG. 5, the MR elements 2 and 4 are connected in series between the power supply terminal to which the power supply voltage Vcc is applied and the ground terminal, and similarly, the MR elements 3 and 1 are also connected in series. And M
The output terminal 8 is provided at the connection point of the R elements 2 and 4, and the MR element 3 and
An output terminal 9 is provided at the connection point of 1, and the voltage between these output terminals 8 and 9 is taken out as an index signal.
ここで、MR素子１〜４は磁界に応じて抵抗値が小さくな
る。Here, the resistance values of the MR elements 1 to 4 decrease according to the magnetic field.
そこで、いま、各MR素子１〜４が着磁領域７に対して第
１図に示す位置にあるとすると、MR素子2,1の抵抗値は
最小となり、出力端子８の電位がMR素子２が磁界中にな
いときの抵抗値における電位よりもδだけ上昇したとす
ると、出力端子９の電位は同じくδだけ下降する。した
がつて、出力端子8,9間の電圧は（＋δ）−（−δ）＝
２δだけMR素子1,2が磁界中にないときよりも上昇す
る。したがつて、MR素子1,2に得られる電圧変化分δの
２倍の電圧変化が得られることになる。なお、このと
き、MR素子3,4も着磁領域のもれ磁界を検出しているた
めに、それらの抵抗値も若干小さくなつているために、
出力端子８の電位はMR素子４の抵抗値変化分低くなり、
出力端子９の電位はMR素子３の抵抗値変化分高くなるか
ら、出力端子8,9間の電圧変化分は２δよりも若干小さ
くなるが、これでも、２δにほぼ等しくてMR素子2,1に
おける電圧降下の変化分δよりも充分大きい。Therefore, assuming that each of the MR elements 1 to 4 is at the position shown in FIG. 1 with respect to the magnetized region 7, the resistance value of the MR elements 2 and 1 becomes the minimum, and the potential of the output terminal 8 becomes equal to that of the MR element 2. If δ rises by δ from the potential at the resistance value when not in the magnetic field, the potential of the output terminal 9 also drops by δ. Therefore, the voltage between the output terminals 8 and 9 is (+ δ)-(-δ) =
It rises by 2δ compared to when the MR elements 1 and 2 are not in the magnetic field. Therefore, a voltage change twice as much as the voltage change δ obtained in the MR elements 1 and 2 can be obtained. At this time, since the MR elements 3 and 4 also detect the leakage magnetic field in the magnetized region, their resistance values are slightly smaller,
The potential of the output terminal 8 becomes lower by the change in the resistance value of the MR element 4,
Since the potential of the output terminal 9 is increased by the change in the resistance value of the MR element 3, the change in the voltage between the output terminals 8 and 9 is slightly smaller than 2δ, but even this is almost equal to 2δ and the MR element 2 and 1 Is sufficiently larger than the change δ of the voltage drop at.
また、MR素子１〜４は着磁領域７に対して第２図に示す
位置にあるとすると、MR素子1,2が着磁領域７からのも
れ磁界を検出することにより、これらの抵抗値は減少
し、これによるMR素子1,2での電圧降下の変化量をδ′
（但し、δ′≪δ）とすると、出力端子8,9間の電圧は
磁界がないときよりも２δ′だけ上昇する。しかし、こ
のとき、MR素子４の抵抗値が最小となるために、出力端
子８の電位はこのMR素子４の抵抗値変化によつて磁界が
ないときよりもδだけ下降されることになり、結局、出
力端子8,9間の電圧は磁界がないときよりも（δ−２
δ′）だけ下降したことになる。Further, assuming that the MR elements 1 to 4 are located at the position shown in FIG. 2 with respect to the magnetized area 7, the MR elements 1 and 2 detect the leakage magnetic field from the magnetized area 7 to detect these resistances. The value decreases, and the change in voltage drop in MR elements 1 and 2 due to this is
(However, if δ '<< δ), the voltage between the output terminals 8 and 9 rises by 2δ' as compared with the case where there is no magnetic field. However, at this time, since the resistance value of the MR element 4 becomes the minimum, the potential of the output terminal 8 is lowered by δ due to the change in the resistance value of the MR element 4 as compared with when there is no magnetic field. After all, the voltage between the output terminals 8 and 9 is (δ-2
This means that it has descended by δ ′).
MR素子１〜４が第３図に示す位置にあるときも、同様に
して、出力端子8,9間の電圧は磁界がないときよりも
（δ−２δ′）だけ下降したことになる。Even when the MR elements 1 to 4 are at the positions shown in FIG. 3, similarly, the voltage between the output terminals 8 and 9 is lowered by (δ-2δ ′) as compared with the case where there is no magnetic field.
ここで、電圧の変化量２δ′は着磁領域７からのもれ磁
界によるものであり、これがMR素子3,4の磁界検出によ
つて除かれるのである。Here, the voltage change amount 2δ ′ is due to the leakage magnetic field from the magnetized region 7, and this is removed by the magnetic field detection of the MR elements 3 and 4.
プラスチツク磁石５が連続的に移動することによつて出
力端子8,9間に得られる電圧は、第４図（ｄ）に示した
ように、MR素子４が着磁領域７に近づくにつれて下降し
始め、第２図に示した状態になつたとき最小となる。し
かる後、この電圧は急激に立上り、第１図に示した状態
になつたとき、MR素子1,2の電圧降下の最大変化量δの
ほぼ２倍となり、その後は急激に立下がる。そして、第
３図の状態になつたときに、出力端子8,9間の電圧は最
小値となり、その後は上昇して磁界がないときの値とな
る。The voltage obtained between the output terminals 8 and 9 due to the continuous movement of the plastic magnet 5 decreases as the MR element 4 approaches the magnetized region 7, as shown in FIG. 4 (d). At the beginning, it becomes the minimum when the state shown in FIG. 2 is reached. Thereafter, this voltage rises rapidly, and when the state shown in FIG. 1 is reached, it is almost twice the maximum change amount δ of the voltage drop of the MR elements 1 and 2, and then falls sharply. When the state shown in FIG. 3 is reached, the voltage between the output terminals 8 and 9 becomes the minimum value, and thereafter rises to the value when there is no magnetic field.
なお、MR素子１〜４の磁気抵抗効果特性が等しいときに
は、これらが磁界中にないときの出力端子8,9間の電圧
は0Vであることはいうまでもない。Needless to say, when the MR elements 1 to 4 have the same magnetoresistive effect characteristics, the voltage between the output terminals 8 and 9 is 0 V when they are not in the magnetic field.
なお、MR素子１〜４の検出出力の合成手段としては、第
５図に示した具体例のみに限るものではない。また、イ
ンデツクス信号の記録媒体としても、プラスチツク磁石
のみに限るものではない。The combination of the detection outputs of the MR elements 1 to 4 is not limited to the specific example shown in FIG. Further, the recording medium for the index signal is not limited to the plastic magnet.
さらに、本発明はモータ制御のためのインデツクス信号
検出のみに限らず、インデツクス信号検出を必要とする
任意の装置に適用することができることはいうまでもな
い。Further, it goes without saying that the present invention can be applied not only to index signal detection for motor control, but also to any device that needs index signal detection.
以上説明したように、本発明によれば、着磁領域７から
もれ磁界が生じても、立上り，立下りが急峻でかつMR素
子の抵抗値変化が２倍となつたのに相当する大振幅で高
いS/Nのインデツクス信号が得られることになり、該着
磁領域の境界を正確かつ簡単に検出することができるよ
うになるという優れた効果が得られる。As described above, according to the present invention, even if a leakage magnetic field is generated from the magnetized region 7, the rising and falling are steep and the change in the resistance value of the MR element is doubled. An S / N index signal having a high amplitude can be obtained, and the excellent effect that the boundary of the magnetized region can be accurately and easily detected can be obtained.
第１図は本発明によるインデツクス信号センサの一実施
例を示す要部構成図、第２図および第３図は夫々プラス
チツク磁石上の着磁領域に対する各磁気抵抗効果素子の
第１図と異なる位置関係を示す図、第４図は第１図にお
ける磁気抵抗効果素子の検出出力とこれらの合成出力で
あるインデツクス信号とを示す波形図、第５図は第１図
における磁気抵抗効果素子の検出出力の合成方法の一具
体例を示す回路図、第６図は従来技術によつて得られる
インデツクス信号を示す波形図である。 １〜４……磁気抵抗効果素子、５……プラスチツク磁
石、６……無着磁領域、７……着磁領域。FIG. 1 is a block diagram of the essential parts showing an embodiment of an index signal sensor according to the present invention, and FIGS. 2 and 3 are the positions of the magnetoresistive effect elements on the magnetized area on the plastic magnet, which are different from those shown in FIG. 4 is a waveform diagram showing the detection output of the magnetoresistive effect element in FIG. 1 and an index signal which is a composite output of these, and FIG. 5 is a detection output of the magnetoresistive effect element in FIG. FIG. 6 is a circuit diagram showing a specific example of the synthesizing method in FIG. 6, and FIG. 6 is a waveform diagram showing an index signal obtained by the conventional technique. 1 to 4 ... Magnetoresistive effect element, 5 ... Plastic magnet, 6 ... Non-magnetized region, 7 ... Magnetized region.
Claims (1)
査し、該着磁領域を検出してインデックス信号を発生す
るインデックス信号センサにおいて、 該走行路に沿って互いに近接しかつ平行に配置された第
1,第２の磁気抵抗効果素子と、 該第１の磁気抵抗効果素子から該走査路に沿って第１の
方向に該着磁領域の長さ分だけ隔てて該第1,第２の磁気
抵抗効果素子と平行に配置された第３の磁気抵抗効果素
子と、 該第２の磁気抵抗効果素子から該走査路に沿って第１の
方向とは反対の第２の方向に該着磁領域の長さ分だけ隔
てて該第1,第２の磁気抵抗効果素子と平行に配置された
第４の磁気抵抗効果素子と を有し、該第１〜第４の磁気抵抗効果素子が該着磁領域
の検出部をなし、該第1,第２の磁気抵抗効果素子の検出
出力の和から該第3,第４の磁気抵抗効果素子の検出出力
を差し引くことにより、該第１〜第４の磁気抵抗効果素
子の検出出力のほぼ２倍でかつ急峻な波形の検出出力を
得ることを特徴とするインデツクス信号センサ。1. An index signal sensor for scanning a scanning path having a magnetized area of a predetermined length and detecting the magnetized area to generate an index signal, wherein the index signal sensors are close to and parallel to each other along the running path. Placed in
First and second magnetoresistive effect elements, and the first and second magnetoresistive elements separated from the first magnetoresistive effect element by the length of the magnetized region in the first direction along the scanning path. A third magnetoresistive effect element arranged in parallel with the resistance effect element, and the magnetized region from the second magnetoresistive effect element along the scanning path in a second direction opposite to the first direction. A fourth magnetoresistive effect element which is arranged in parallel with the first and second magnetoresistive effect elements at a distance of, and the first to fourth magnetoresistive effect elements are A detection unit for the magnetic region is formed, and by subtracting the detection outputs of the third and fourth magnetoresistive effect elements from the sum of the detection outputs of the first and second magnetoresistive effect elements, the first to fourth An index signal sensor which is capable of obtaining a detection output having a steep waveform that is almost twice the detection output of the magnetoresistive effect element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61247622A JPH0690045B2 (en) | 1986-10-20 | 1986-10-20 | Index signal sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61247622A JPH0690045B2 (en) | 1986-10-20 | 1986-10-20 | Index signal sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63101786A JPS63101786A (en) | 1988-05-06 |
| JPH0690045B2 true JPH0690045B2 (en) | 1994-11-14 |
Family
ID=17166245
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61247622A Expired - Lifetime JPH0690045B2 (en) | 1986-10-20 | 1986-10-20 | Index signal sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0690045B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3259316B2 (en) * | 1992-02-07 | 2002-02-25 | ソニー株式会社 | Position detection device, lens device, video camera |
| US5861747A (en) * | 1997-05-27 | 1999-01-19 | Ford Global Technologies, Inc. | Magnetoresistive rotary position sensor providing a linear output independent of modest fluctuations |
| SE529125C2 (en) * | 2005-03-02 | 2007-05-08 | Tetra Laval Holdings & Finance | Method and apparatus for determining the position of a packaging material with magnetic markings |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59166812A (en) * | 1983-03-14 | 1984-09-20 | Fanuc Ltd | One rotation detecting system of motor |
-
1986
- 1986-10-20 JP JP61247622A patent/JPH0690045B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63101786A (en) | 1988-05-06 |
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