JP3846371B2 - Rotation detector - Google Patents

Description

【００２８】
はＥＯＲ回路４３の入力端子４３ＡとＥＮＯＲ回路４１の入力端子４１Ａに接続されている。第２のフリップフロップ４５のデータ入力端子Ｄ２はＥＯＲ回路４２の出力端子に接続され、第２のフリップフロップ４５のクロック入力端子ＣＬ２はインバータ回路２５の出力端子に接続され、第２のフリップフロップ４５の
【００２９】
【外２】

【００３０】
はＥＯＲ回路４３の入力端子４３ＢとＥＯＲ回路４２の入力端子４２Ａに接続されている。
【００３１】
ＥＮＯＲ回路４１およびＥＯＲ回路４２の入力端子４１Ｂ、４２Ｂは、比較器３１の出力端子に接続されている。ＥＯＲ回路４３の出力端子からは方向判別信号Ｓｄｅとして出力端子４Ｓ２より出力される。
【００３２】
次に本実施の形態の動作について図４のタイムチャートを用いて説明する。
【００３３】
図４はギア１が正回転をしている状態から逆回転に転じ、更に正回転に転じた時の各部信号の波形を示すものである。ギア１の回転により磁気センサ部３は図４（ａ）に示すような素子出力が得られる。この素子出力が第１、第２、第３の信号発生回路１０，２０，３０に入力され、それぞれの閾値電位（ＶＴＨ１、ＶＴＨ２、ＶＴＨ３、ＶＴＨ４）にて比較判定され、各信号が出力される（同図（ｂ），（ｃ），（ｄ）参照）。第３の信号発生回路３０の出力信号Ｓｏはそのままセンサ信号として出力される。ＥＮＯＲ回路４１は、第３の信号発生回路３０の出力信号Ｓｏと第１のフリップフロップ４４のＱバー出力の入力信号を演算して、出力信号が第１のフリップフロップ４４のデータ入力端子Ｄ１に入力される。第１のフリップフロップ４４のクロック入力端子ＣＬ１には第２の信号発生回路２０の出力信号Ｓｄが入力されるので、出力信号Ｓｄの立ち上がりタイミングでハイレベルの信号を判定信号Ｓｆ１として出力するようになる。また、ＥＯＲ回路４２では、第３の信号発生回路３０の出力信号Ｓｏと第２のフリップフロップ４５のＱバー出力を演算して、出力信号が第２のフリップフロップ４５のデータ入力端子Ｄ２に入力される。第２のフリップフロップ４５のクロック入力端子ＣＬ２には第１の信号発生回路１０の出力信号Ｓｕがインバータ回路２５を介して入力されるので、出力信号Ｓｕの立ち下がりタイミングでロウレベルの信号を判定信号Ｓｆ２として出力するようになる。そして、これら判定信号Ｓｆ１とＳｆ２がＥＯＲ回路４３に入力され、演算処理によってＥＯＲ回路４３の出力端子より方向判別信号Ｓｄｅとして出力されることにより、ギア１の回転方向を検出することができる。
【００３４】
本実施の形態においては、第１の信号発生手段１０の出力信号と第２の信号発生手段２０の出力信号と第３の信号発生手段３０の出力信号と回転方向判別回路４０を用いた所について説明してきたが、必ずしもこれに特定されるものではない。すなわち、本発明の技術思想の中核は第３の信号発生回路３０の出力信号を基準として、第１の信号発生回路１０の出力信号または、第２の信号発生回路２０の出力信号の立ち上がりまたは立ち下がりを用いて、回転体の回転方向を可能にするところにある。
【００３５】
（実施の形態２）
本発明の第２の実施の形態について、図５，６を用いて説明する。
【００３６】
図５は本発明の第２の実施の形態を示すもので、以下、第１の実施の形態と異なる部分について説明する。この実施の形態における回転検出装置においては、ギア１の回転方向が反転したときに、センサの出力によって回転方向を判別する場合に対応してなされたもので、回転方向によってセンサの出力レベルを切換えるための出力レベル切換え回路５０を設けた構成としている。
【００３７】
出力レベル切換え回路５０は、出力端子４Ｓ１とＧＮＤ端子間に抵抗５２とトランジスタ５５が接続され、これと並列に抵抗５３が接続されている。抵抗５２の両端には、回転方向判別回路４０からの方向判別信号Ｓｄｅに応じて出力信号レベルを切換えるために導通又は遮断されるデジタルスイッチ５６が接続され、抵抗５３の両端には、直列接続されたデジタルスイッチ５７と抵抗５４が接続されている。ＥＯＲ回路４３の出力端子はインバータ回路５８を介してデジタルスイッチ５６に接続されると共に、デジタルスイッチ５７に対して直接接続されている。第３の信号発生回路３０の出力信号Ｓｏは抵抗５１を介してトランジスタ５５のベース端子に接続される。
【００３８】
次に本実施の形態の動作について図６のタイムチャートを用いて、第１の実施の形態と異なる部分について説明する。図６中、（ａ）は磁気センサ部３の素子出力であり、（ｂ），（ｃ），（ｄ）は第１，２，３の信号発生回路１０，２０，３０の出力信号であり、（ｅ）は判定信号Ｓｆ１であり、（ｆ）は判定信号Ｓｆ２であり、（ｇ）は回転方向判別の出力信号の波形である。
【００３９】
抵抗５１を介してトランジスタ５５のベース端子に入力された第３の信号発生回路３０の出力信号Ｓｏはトランジスタ５５のコレクタ端子より出力され、回転方向判別回路４０の出力信号Ｓｄｅとそれがインバータ回路５８により反転された出力信号Ｓｔｃ（同図（ｈ）参照）によりデジタルスイッチ５６，５７のいずれかがＯＮすることにより、出力信号Ｓｏのハイレベル、ロウレベル電位が抵抗５２，５３，５４の設定値による電位レベルに切り換わった信号Ｓｏｄを得る事ができ、出力端子４Ｓ１より、センサ信号として出力される（同図（ｉ）参照）。
【００４０】
上記構成により、ギア１の回転方向に応じて出力信号レベルが異なるようになるので、確実に回転方向を検出することが出来ると共に、抵抗とスイッチという簡単な回路で構成できる為、抵抗値を変えることで様々な出力レベルが選択可能となる。
【００４１】
なお、本実施の形態はデジタルスイッチを用いて説明したが、アナログスイッチにおいても同様の動作を得ることができる。
【００４２】
【発明の効果】
以上のように本発明によれば、回転体に対向配置されその回転に伴って変化する信号を出力する磁気センサと、前記磁電変換素子の出力信号が入力され、この出力信号に対して第１のしきい値を持つ第１の信号発生手段と、前記出力信号が入力され、前記第１の信号発生手段の第１のしきい値よりも小さい第２のしきい値を持つ第２の信号発生手段と、前記出力信号が入力され前記第１のしきい値よりも大きい第３のしきい値と前記第２のしきい値よりも小さい第４のしきい値を持った第３の信号発生手段と、前記第３の信号発生手段の出力信号を基準として前記第１の信号発生手段の出力信号または前記第２の信号発生手段の出力信号の立ち上がりまたは立ち下がりを用いて前記回転体の回転方向に対応する判定信号を出力するものであり、１組のブリッジ構成された磁気センサを用い被検出対象としての歯の形状に制約を受けずに回転方向を検出することができる回転検出装置を実現できる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態を示す回転検出装置のブロック図
【図２】同装置の具体回路ブロック図
【図３】同装置の素子出力と各閾値電位と信号を説明する為の波形図
【図４】同装置の各部の信号出力の波形図
【図５】本発明の第２の実施の形態を示す回転検出装置の具体回路ブロック図
【図６】同装置の各部の信号出力の波形図
【符号の説明】
１ ギア（回転体）
２ 回転検出装置
３ 磁気センサ部
３ａ バイアス磁石
４ 処理回路部
１０ 第１の信号発生回路
１１，２１，３１ 比較器
１２〜１８ 抵抗
２０ 第２の信号発生回路
２２ 突部
２５ インバータ回路
３０ 第３の信号発生回路
３２，３３ 磁気センサ素子
４１ ＥＮＯＲ回路
４２，４３ ＥＯＲ回路
４４，４５ フリップフロップ
５０ 出力レベル切換え回路
５１〜５４ 抵抗
５５ トランジスタ
５６，５７ デジタルスイッチ
５８ インバータ回路[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotation detection device that detects the rotation speed and rotation direction of a rotating gear made of a magnetic material in a non-contact manner using a set of magnetic sensors, and detects the rotation speed and rotation direction of an automobile wheel or an engine. It is suitable for use in sensors.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a rotation detection device for detecting a rotating detection target is known as disclosed in JP-A-11-83890. In this rotation detection device, the tooth provided on the detection target has two sides parallel to the rotation axis of the detection target, and the side closer to the rotation axis is the far side of the two sides In the two hypotenuses different from the two parallel sides of the four sides forming the trapezoidal shape, the slope of one side of the hypotenuse is made to be the slope of the other side. The direction of rotation is detected by a set of magnetoresistive element bridges by making them steeper than the gradient.
[0003]
[Problems to be solved by the invention]
However, the conventional apparatus has a problem that the shape of the tooth is not an isosceles trapezoid as a detection target, and one side must be different from the other side. There is no freedom.
[0004]
Therefore, the present invention has been made in view of the above problems, and detects a rotation direction without being restricted by the shape of a tooth as a detection target using a pair of bridge-structured magnetic sensors. An object of the present invention is to provide a rotation detection device that can perform the above-described operation.
[0005]
[Means for Solving the Problems]
In order to achieve such an object, the present invention has the following configuration.
[0006]
The invention according to claim 1 of the present invention is arranged to be opposed to the rotating body, to output a signal that periodically changes as the rotating body rotates, and to output an output signal of the magnetic sensor, A first signal generating means having a first threshold for the output signal, and a second signal smaller than the first threshold of the first signal generating means when the output signal is input. A second signal generating means having a threshold value; a third threshold value greater than the first threshold value; and a fourth threshold value less than the second threshold value when the output signal is input. A third signal generating means having a threshold value, a rise of the output signal of the first signal generating means or the output signal of the second signal generating means with reference to the output signal of the third signal generating means; A judgment signal corresponding to the direction of rotation of the rotating body using a falling edge. The a rotation detecting apparatus and a rotation direction determination means to output, it is possible to detect the rotation direction and the rotation speed of the rotating body without being constrained to the shape of the teeth of the rotating body as an object to be detected.
[0007]
According to a second aspect of the present invention, in the first aspect of the invention, there is provided output level switching means for switching the output level depending on the rotational direction based on the signal of the rotational direction discriminating means. Since the output level becomes different, the rotation direction can be reliably detected.
[0008]
The invention according to claim 3 is characterized in that, in the invention according to claim 2, the output level switching means switches the pull-up resistor connected to the output section by means of a switch. It can be configured by a circuit, and has an advantage that various output levels can be selected by changing the value of the pull-up resistor.
[0009]
The invention according to claim 4 uses a semiconductor magnetoresistive element as the magnetic sensor in the invention according to claim 1, and this results in a four-terminal structure when a Hall element is used. The structure is a two-terminal structure, and the structure is simple. In addition, various arrangements with high magnetic sensitivity suitable for the pitch of the concave and convex portions of the gears are possible, and a rotation detection device that detects various gears can be provided.
[0010]
According to a fifth aspect of the present invention, in the second aspect of the present invention, a transistor is provided between the output of the rotation direction discriminating means and the output level switching means. This has the advantage of not affecting the rotation direction discriminating means.
[0011]
According to a sixth aspect of the present invention, in the first aspect of the present invention, the rotation direction discriminating means includes a D-type first and second flip-flops and a circuit that negates an exclusive OR of two inputs (hereinafter referred to as ENOR). A first two-input exclusive OR circuit (hereinafter referred to as an EOR circuit) and an inverter circuit. The first flip-flop has its data input terminal connected to the output terminal of the ENOR circuit. The clock input terminal is connected to the input terminal of the rotation direction discriminating means, the Q bar output terminal is connected to the input terminal of the second EOR circuit and the input terminal of the ENOR circuit, and the second flip-flop Has its data input terminal connected to the output terminal of the first EOR circuit, its clock input terminal connected to the input terminal of the rotation direction discriminating means via the inverter circuit, and its Q buffer. The output terminal is connected to the input terminal of the second EOR circuit and the input terminal of the first EOR circuit, and the direction determination signal is output from the output terminal of the second EOR circuit. Therefore, there is an advantage that the rotation direction discriminating means can be realized with a relatively simple circuit configuration.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
[0013]
FIG. 1 is a block diagram for explaining a first embodiment of the rotation detecting apparatus of the present invention.
[0014]
FIG. 2 is a block diagram of a specific circuit of the rotation detection device.
[0015]
As shown in FIGS. 1 and 2, the rotation detection device 2 includes, for example, a gear 1 as a rotating body that is a target for detecting the rotation speed, rotation position, and rotation direction of an automobile wheel or an engine, and rotation of the gear 1. And a signal processing circuit 4 that performs waveform processing on the output waveform of the magnetic sensor unit 3.
[0016]
The magnetic sensor unit 3 includes a pair of magnetic sensor elements 32 and 33 configured as a bridge, and a bias magnet 3 a that generates a predetermined magnetic field with respect to the magnetic sensor elements 32 and 33. The gear 1 to be detected is arranged with a predetermined gap. The bias magnet 3a is made of a permanent magnet, and one surface side is magnetized to the N pole and the other surface side is magnetized to the S pole, and generates a bias magnetic field in a direction substantially perpendicular to the magnetized surface. The magnetic sensor elements 32 and 33 are arranged so as to face the outer peripheral portion of the gear 1, and output signals that periodically change with the rotation of the gear 1. As the magnetic sensor elements 32 and 33, for example, semiconductor magnetoresistive elements are used. In addition, since the constant voltage Vcc is applied to both ends of the magnetic sensor elements 32 and 33, the midpoint potential of the magnetic sensor elements 32 and 33 changes to a sine wave shape as shown in FIG. It is taken out as output S1 (hereinafter, this voltage is referred to as element output).
[0017]
The magnetic sensor elements 32 and 33 may be MR elements (magnetoresistive elements), GMR elements (giant magnetoresistive elements), MI elements as long as they can output a periodic signal due to a change in magnetic flux accompanying the rotation of the gear 1. Other detection means such as (magnetic impedance element) may be used.
[0018]
On the other hand, the gears 1 to be detected are provided with protrusions 22 intermittently and continuously as shown in FIG. And as shown by the arrow of FIG. 1, the gear 1 is performing forward / reverse rotation. The protrusions 22 are for changing the outputs of the magnetic sensor elements 32 and 33 with rotation. As shown in FIG. 1, the protrusions 22 are provided at a predetermined pitch on the outer periphery of the gear 1, and the gear 1 rotates. It is configured to move on the same track. The gear 1 may be entirely composed of a magnetic body including the protrusions 22, but only the protrusions 22 may be formed of a magnetic body. Further, even if the width dimension of the protrusion 22 and the gap dimension between the protrusions 22 and 22 have a one-to-one relationship, the rotation direction of the gear 1 can be detected.
[0019]
Note that the gear 1 is not limited to the one having the protruding protrusions 22 as shown in FIG. 1, and signals that periodically change from the magnetic sensor elements 32 and 33 as the gear 1 rotates. Any other structure or shape may be used as long as it is output.
[0020]
The signal processing circuit 4 binarizes the element output to convert it into a pulse signal and generates a direction determination signal. The signal processing circuit 4 is a part for generating a direction determination signal, and is connected to a power supply terminal 4a for applying a Vcc voltage, a GND terminal 4b, and an element output. The terminal 4n, the sensor output terminal 4S1, the direction determination signal output terminal 4S2, the first signal generation circuit 10, the second signal generation circuit 20, the third signal generation circuit 30, and the rotation direction determination circuit 40 are configured. .
[0021]
As shown in FIG. 2, the first signal generation circuit 10 has an element output S1 that has passed through the input terminal 4n of the signal processing circuit 4 connected to the inverting input terminal of the comparator 11 and connected to the non-inverting input terminal. The signal is binarized with a threshold value VTH1 of 1, and a first signal Su as shown in FIG. 3 is output.
[0022]
As shown in FIG. 2, in the second signal generation circuit 20, the element output S1 that has passed through the input terminal 4n of the signal processing circuit 4 is connected to the inverting input terminal of the comparator 21 and connected to the non-inverting input terminal. The signal is binarized with a threshold value VTH2 of 2, and a second signal Sd as shown in FIG. 3 is output.
[0023]
The threshold values of the first and second signal generation circuits 10 and 20 are set by resistors 12 to 15 connected in series between the power supply voltage Vcc terminal and the GND terminal. The resistors 12 and 15 and the resistors 13 and 14 have the same resistance value. The midpoint between the resistors 12 and 13 is connected to the non-inverting input terminal of the comparator 11, and the midpoint between the resistors 14 and 15 is connected to the non-inverting input terminal of the comparator 21. According to this threshold value setting, a first threshold value VTH1 higher than the Vcc / 2 potential and a second threshold value VTH2 lower than the Vcc / 2 potential are obtained.
[0024]
As shown in FIG. 2, the third signal generation circuit 30 has an element output S1 that has passed through the input terminal 4n of the signal processing circuit 4 connected to the inverting input terminal of the comparator 31 and connected to the non-inverting input terminal. 2 and binarized by the third threshold values VTH3 and VTH4, and the third signal So is output. The third signal So is output from the output terminal 4S1 of the signal processing circuit 4 as a sensor signal.
[0025]
The threshold value of the third signal generating circuit 30 is that the resistors 16 and 17 connected in series between the power supply voltage Vcc terminal and the GND terminal, and the resistor 18 connected between the output terminal and the non-inverting input terminal of the comparator 31. Set by The midpoint of the resistors 16 and 17 is connected to the non-inverting input terminal of the comparator 31 and is connected to the output terminal of the comparator 31 via the resistor 18. According to this threshold value setting, the third threshold value VTH3 is larger than the first threshold value VTH1, and the fourth threshold value VTH4 is smaller than the second threshold value VTH2, so that the resistors 16, 17, and 18 Set the value. The fourth threshold value VTH4 is set to be lower by Vh than the third threshold voltage VTH3 when a low level signal is output from the output of the comparator 31.
[0026]
The rotation direction discriminating circuit 40 includes D-type first and second flip-flops 44 and 45, a circuit (hereinafter referred to as ENOR) 41 that negates exclusive OR, and an exclusive OR circuit (hereinafter referred to as EOR) 42. , 43. The data input terminal D1 of the first flip-flop 44 is connected to the output terminal of the ENOR circuit 41, the clock input terminal CL1 of the first flip-flop 44 is connected to the output terminal of the comparator 21, and the first flip-flop 44 is connected. [0027]
[Outside 1]

[0028]
Are connected to the input terminal 43A of the EOR circuit 43 and the input terminal 41A of the ENOR circuit 41. The data input terminal D2 of the second flip-flop 45 is connected to the output terminal of the EOR circuit 42, the clock input terminal CL2 of the second flip-flop 45 is connected to the output terminal of the inverter circuit 25, and the second flip-flop 45 is connected. [0029]
[Outside 2]

[0030]
Are connected to the input terminal 43B of the EOR circuit 43 and the input terminal 42A of the EOR circuit 42.
[0031]
The input terminals 41B and 42B of the ENOR circuit 41 and the EOR circuit 42 are connected to the output terminal of the comparator 31. The direction determination signal Sde is output from the output terminal 4S2 from the output terminal of the EOR circuit 43.
[0032]
Next, the operation of the present embodiment will be described with reference to the time chart of FIG.
[0033]
FIG. 4 shows the waveform of each signal when the gear 1 turns from the forward rotation to the reverse rotation and further to the forward rotation. With the rotation of the gear 1, the magnetic sensor unit 3 can obtain an element output as shown in FIG. This element output is input to the first, second, and third signal generation circuits 10, 20, and 30, and is compared and determined at each threshold potential (VTH1, VTH2, VTH3, VTH4), and each signal is output. (See (b), (c), (d) in the figure). The output signal So of the third signal generation circuit 30 is output as a sensor signal as it is. The ENOR circuit 41 calculates the output signal So of the third signal generation circuit 30 and the input signal of the Q-bar output of the first flip-flop 44, and the output signal is input to the data input terminal D1 of the first flip-flop 44. Entered. Since the output signal Sd of the second signal generation circuit 20 is input to the clock input terminal CL1 of the first flip-flop 44, a high level signal is output as the determination signal Sf1 at the rising timing of the output signal Sd. Become. The EOR circuit 42 calculates the output signal So of the third signal generation circuit 30 and the Q-bar output of the second flip-flop 45 and inputs the output signal to the data input terminal D2 of the second flip-flop 45. Is done. Since the output signal Su of the first signal generation circuit 10 is input to the clock input terminal CL2 of the second flip-flop 45 via the inverter circuit 25, a low-level signal is determined at the falling timing of the output signal Su. It outputs as Sf2. Then, these determination signals Sf1 and Sf2 are input to the EOR circuit 43, and output as a direction determination signal Sde from the output terminal of the EOR circuit 43 by arithmetic processing, whereby the rotation direction of the gear 1 can be detected.
[0034]
In the present embodiment, the output signal of the first signal generation means 10, the output signal of the second signal generation means 20, the output signal of the third signal generation means 30, and the rotation direction discrimination circuit 40 are used. Although described, this is not necessarily specific. That is, the core of the technical idea of the present invention is the rise or rise of the output signal of the first signal generation circuit 10 or the output signal of the second signal generation circuit 20 on the basis of the output signal of the third signal generation circuit 30. By using the lowering, the rotation direction of the rotating body is made possible.
[0035]
(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIGS.
[0036]
FIG. 5 shows a second embodiment of the present invention, and the following description will be focused on differences from the first embodiment. In the rotation detection device in this embodiment, when the rotation direction of the gear 1 is reversed, the rotation direction is determined based on the output of the sensor, and the output level of the sensor is switched depending on the rotation direction. The output level switching circuit 50 is provided.
[0037]
In the output level switching circuit 50, a resistor 52 and a transistor 55 are connected between the output terminal 4S1 and the GND terminal, and a resistor 53 is connected in parallel therewith. Connected to both ends of the resistor 52 is a digital switch 56 that is turned on or off in order to switch the output signal level in accordance with the direction determination signal Sde from the rotation direction determination circuit 40, and is connected in series to both ends of the resistor 53. The digital switch 57 and the resistor 54 are connected. The output terminal of the EOR circuit 43 is connected to the digital switch 56 via the inverter circuit 58 and also directly connected to the digital switch 57. The output signal So of the third signal generation circuit 30 is connected to the base terminal of the transistor 55 via the resistor 51.
[0038]
Next, the operation of this embodiment will be described with reference to the time chart of FIG. In FIG. 6, (a) is an element output of the magnetic sensor unit 3, and (b), (c), and (d) are output signals of the first, second, and third signal generation circuits 10, 20, and 30. , (E) is the determination signal Sf1, (f) is the determination signal Sf2, and (g) is the waveform of the output signal for determining the rotation direction.
[0039]
The output signal So of the third signal generation circuit 30 input to the base terminal of the transistor 55 through the resistor 51 is output from the collector terminal of the transistor 55, and the output signal Sde of the rotation direction determination circuit 40 and the inverter circuit 58 When either one of the digital switches 56 and 57 is turned ON by the output signal Stc inverted by (see (h) in the same figure), the high level and low level potentials of the output signal So depend on the set values of the resistors 52, 53 and 54. The signal Sod switched to the potential level can be obtained, and is output as a sensor signal from the output terminal 4S1 (see (i) in the figure).
[0040]
With the above configuration, the output signal level varies depending on the rotation direction of the gear 1, so that the rotation direction can be detected reliably, and a simple circuit such as a resistor and a switch can be used to change the resistance value. Thus, various output levels can be selected.
[0041]
Although the present embodiment has been described using a digital switch, a similar operation can also be obtained with an analog switch.
[0042]
【The invention's effect】
As described above, according to the present invention, the magnetic sensor that is disposed to face the rotating body and outputs a signal that changes in accordance with the rotation, and the output signal of the magnetoelectric conversion element are input, and the first output is output to the output signal. First signal generating means having a threshold value of 2 and a second signal having a second threshold value smaller than the first threshold value of the first signal generating means, to which the output signal is input And a third signal having a third threshold value greater than the first threshold value and a fourth threshold value smaller than the second threshold value to which the output signal is input. Generating means and an output signal of the first signal generating means or a rising or falling edge of the output signal of the second signal generating means with reference to the output signal of the third signal generating means. A judgment signal corresponding to the direction of rotation is output. The rotation detecting device capable of detecting the direction of rotation without being restricted to the shape of the teeth of the object to be detected using a set of bridge configured magnetic sensor was realized.
[Brief description of the drawings]
FIG. 1 is a block diagram of a rotation detection device showing a first embodiment of the present invention. FIG. 2 is a specific circuit block diagram of the device. FIG. 3 is a diagram illustrating element outputs, threshold potentials, and signals of the device. FIG. 4 is a waveform diagram of the signal output of each part of the apparatus. FIG. 5 is a specific circuit block diagram of the rotation detecting apparatus showing the second embodiment of the invention. Waveform diagram of signal output [Explanation of symbols]
1 Gear (Rotating body)
2 rotation detection device 3 magnetic sensor unit 3a bias magnet 4 processing circuit unit 10 first signal generation circuit 11, 21, 31 comparators 12 to 18 resistor 20 second signal generation circuit 22 protrusion 25 inverter circuit 30 third Signal generation circuit 32, 33 Magnetic sensor element 41 ENOR circuit 42, 43 EOR circuit 44, 45 Flip-flop 50 Output level switching circuit 51-54 Resistance 55 Transistor 56, 57 Digital switch 58 Inverter circuit

Claims (6)

A magnetic sensor that is disposed opposite to the rotating body and outputs a signal that changes as the rotating body rotates, and an output signal of the magnetic sensor is input. 1 signal generating means, the second signal generating means to which the output signal is input and having a second threshold value smaller than the first threshold value of the first signal generating means, and the output signal , And a third signal generating means having a third threshold value greater than the first threshold value and a fourth threshold value smaller than the second threshold value, 3. A determination corresponding to the rotation direction of the rotating body using the output signal of the first signal generation means or the rise and fall of the output signal of the second signal generation means with reference to the output signal of the signal generation means 3 Rotation direction discriminating means for outputting a signal Detection device. 2. The rotation detection device according to claim 1, further comprising output level switching means for switching an output level controlled by an output signal of the rotation direction discriminating means depending on the rotation direction. 3. The rotation detecting device according to claim 2, wherein the output level switching means switches the output level by switching a pull-up resistor connected to the output unit with a switch. The rotation detection device according to claim 1, wherein the magnetic sensor is a semiconductor magnetoresistive element. 3. A rotation detection apparatus according to claim 2, wherein a transistor is provided between an output of the rotation direction determination means and the output level switching means. The rotation direction discriminating means includes a D type first and second flip-flop, a circuit that negates an exclusive OR of two inputs (hereinafter referred to as an ENOR circuit), and an exclusive first and second two inputs. It consists of an OR circuit (hereinafter referred to as EOR circuit) and an inverter circuit. The first flip-flop has its data input terminal connected to the output terminal of the ENOR circuit and its clock input terminal connected to the input terminal of the rotation direction discriminating means. The Q-bar output terminal is connected to the input terminal of the second EOR circuit and the input terminal of the ENOR circuit, and the data input terminal of the second flip-flop is connected to the output terminal of the first EOR circuit. The clock input terminal is connected to the input terminal of the rotation direction discriminating means through the inverter circuit, and the Q bar output terminal is connected to the input terminal of the second EOR circuit and the first EOR. Is connected to the input terminal of the road, the rotation detecting device according to claim 1, wherein the direction discrimination signal from the output terminal of the second EOR circuit is configured to output.

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