JP2012185077A - Magnetic sensor adjustment method and magnetic sensor adjustment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic sensor adjustment method and a magnetic sensor adjustment device reducing complicated magnetic sensor adjustment processes.SOLUTION: The magnetic sensor adjustment method is for adjusting output characteristics of a magnetic sensor (10) comprising a magnetoelectric transducer (20), a magnet (30), and a signal processing unit (43) that binarizes an output signal of the magnetoelectric transducer (20) based on a threshold voltage. There are measured a voltage value Va of a first output signal of the magnetoelectric transducer (20) when a distance between a magnetic material (70) and the magnetic sensor (10) is at a first distance, and a voltage value Vb of a second output signal of the magnetoelectric transducer (20) when the distance between the magnetic material (70) and the magnetic sensor (10) is at a second distance. A voltage level of the output signal of the magnetoelectric transducer (20) is adjusted such that, when factors related to the output characteristics of the magnetoelectric transducer (20) are represented as a and b, and the threshold voltage as Vth, Vth=a×ln(Vb-Va)+b+Va is satisfied.

Description

  The present invention includes a magnetoelectric conversion element, a magnet that forms a magnetic field around the magnetoelectric conversion element, and a signal processing unit that binarizes an output signal of the magnetoelectric conversion element based on a threshold voltage, and rotates the rotating body. The present invention relates to a magnetic sensor adjustment method for adjusting output characteristics of a magnetic sensor for detecting a state, and a magnetic sensor adjustment device.

  Conventionally, as shown, for example, in Patent Document 1, a magnetic field detection unit disposed between a magnet and a detection target unit, and waveform processing for binarizing a detection waveform output from the magnetic field detection unit based on a threshold value There has been proposed a method for adjusting a magnetic sensor, which includes a control unit and a threshold value adjustment / setting unit that adjusts and sets a threshold value. In the detected body unit, magnetically non-equivalent first detected parts and second detected parts are alternately arranged along the movement path (rotation direction). The two detection parts) and the magnetic field detection part are separated by a detection gap length. In this magnetic sensor adjustment method, the detection gap length is changed between a plurality of set values, and the detection waveform of the magnetic field detection unit is acquired for each set value of the detection gap lengths. Then, the intersection level value indicated by the intersection between the waveforms when the plurality of acquired detection waveforms are superimposed in the same phase is calculated, and the threshold value is adjusted so as to coincide with the calculated intersection level value.

  When the detection gap length deviates from the initial set value, the amplitude of the obtained detection waveform changes and binarization changes. However, according to the inventor of Patent Document 1, it has been found that if the waveforms changed by the influence of the detection gap length are overlapped in phase, the detection waveforms intersect at one point regardless of the detection gap length. The voltage level at this intersection is a value that does not depend on the detection gap length. Therefore, as described above, binarization can be performed regardless of the detection gap length by adjusting the threshold value so as to coincide with the intersection level value.

JP 2004-301645 A

  By the way, in the magnetic sensor adjustment method disclosed in Patent Document 1, in order to change the detection gap length between a plurality of set values, instead of the detection target unit for detection in which the detection gap length is uniform, A variable gap detected body unit for adjustment in which sections having different detection gap lengths are mixed is assembled to a magnetic sensor. Since the variable gap detected body unit is a rotating body, in order to make the variable gap detected body unit and the magnetic sensor to be adjusted face each other, the magnetic sensor must be arranged in the circumferential direction of the variable gap detected body unit. . When one magnetic sensor is an adjustment target, there is little possibility that the adjustment of the magnetic sensor is complicated even with the above method. However, for example, when 1,000 magnetic sensors are to be adjusted, the magnetic sensors must be sequentially arranged in the circumferential direction, and adjustment may be complicated.

  In view of the above problems, an object of the present invention is to provide a magnetic sensor adjustment method and a magnetic sensor adjustment device in which adjustment of the magnetic sensor is suppressed from being complicated.

が成立するように、磁電変換素子（２０）の出力信号の電圧レベルを調整する調整工程と、を有することを特徴とする。 In order to achieve the above object, the invention described in claim 1 includes a magnetoelectric conversion element (20), a magnet (30) that forms a magnetic field around the magnetoelectric conversion element (20), and a magnetoelectric conversion element ( The magnetic sensor adjustment method includes a signal processing unit (43) that binarizes the output signal of 20) based on a threshold voltage, and adjusts the output characteristics of the magnetic sensor (10) that detects the rotation state of the rotating body. The magnetic body (70) for changing the magnetic field formed by the magnet (30) and the magnetic sensor (10) are output by the first of the magnetoelectric transducer (20) output when the magnetic sensor (10) is separated by the first distance. The voltage value Va of the output signal and the second output of the magnetoelectric transducer (20) output when the magnetic body (70) and the magnetic sensor (10) are separated by a second distance different from the first distance. A measurement process for measuring the voltage value Vb of the signal, and after the measurement process The coefficients relating to the output characteristics of the magnetoelectric converting element (20) a, b, when the threshold voltage is Vth, the following formula

And an adjustment step of adjusting the voltage level of the output signal of the magnetoelectric transducer (20) so as to hold.

  As a result of investigation by the present inventor, the following points were found. The distance (detection gap length) between the rotating body and the magnetoelectric conversion element (20) is changed between a plurality of set values, and the output signal (waveform signal) of the magnetoelectric conversion element (20) is changed for each set value of the detection gap length. get. Then, a voltage value V0 (voltage value independent of the detection gap length) of the intersection point between the signals when the plurality of acquired waveform signals are superimposed in the same phase is calculated. This was calculated by a plurality of magnetic sensors (10), and data points indicating the correlation with the output sensitivity (Vb−Va) of each magnetic sensor (10) were created. Then, when an approximate expression connecting the data points was created, it was found that V0 = α × ln (Vb−Va) + β (α and β are real numbers). According to this, as described in claim 1, after measuring the voltage values Va and Vb instead of the waveform signal of the magnetoelectric conversion element (20), the magnetoelectric conversion element (20) By adjusting the voltage level of the output signal, the voltage level of the threshold voltage Vth can be set to a voltage value that does not depend on the detection gap length.

  In order to obtain the voltage values Va and Vb, as described in claim 1, it is only necessary to change the relative distance between the magnetic sensor (10) and the magnetic body (70) twice. According to this, as the shape of the magnetic body (70), it is possible to select a shape that is easy to be opposed to the plurality of magnetic sensors (10) to be adjusted, instead of being circular. As a result, the adjustment of the magnetic sensor (10) is suppressed from becoming complicated.

  According to a second aspect of the present invention, the plurality of magnetic sensors (10) are opposed to the main surface of the magnetic body (70) in a direction perpendicular to the facing direction of the magnetic sensor (10) and the magnetic body (70). In addition, before performing the measurement process, any one of the plurality of magnetic sensors (10) is adjusted to adjust the voltage level of the output signal of the magnetoelectric transducer (20). It is preferable to have a connection step of electrically connecting the part (80) and performing the connection step to the adjustment step by all the magnetic sensors (10).

  As described above, since the plurality of magnetic sensors (10) to be adjusted are linearly arranged, the adjustment of the magnetic sensor (10) is complicated compared to the configuration in which the magnetic sensors (10) are arranged in an arc. Is suppressed. In addition, since the electrical connection between the magnetic sensor (10) and the adjustment unit (80) is controlled, an apparatus for adjusting the magnetic sensor (10) as compared with a configuration in which one adjustment unit is provided for each magnetic sensor. An increase in the size of the (magnetic sensor adjustment device) is suppressed.

で近似することで、係数ａ，ｂを算出する第２算出工程と、を有し、第２算出工程後、計測工程及び調整工程を、調整対象となる全ての磁気センサ（１０）で行うのが良い。 A selection step of arbitrarily selecting one magnetic sensor (10) from among a plurality of magnetic sensors (10) to be adjusted before performing the measurement step, and the selection step Then, the selected magnetic sensor (10) and the rotating body in a rotating state are opposed to each other, and the relative distance between the selected magnetic sensor (10) and the rotating body is changed at least twice, so that the relative distance between the relative distances The first acquisition step of acquiring the output signal of the magnetoelectric conversion element (20) and the phase of the output signal of the magnetoelectric conversion element (20) between the relative distances after the first acquisition step are overlapped. Thus, the first calculation step for calculating the voltage value V0 at the intersection point where the output signals cross each other, and after the first calculation step, the selected magnetic sensor (10) and the magnetic body (70) are opposed to each other, so that the magnetic body (70) and magnetic sensor (10) are the third distance The voltage value Vc of the third output signal of the magnetoelectric conversion element (20) output when separated, and the magnetic body (70) and the magnetic sensor (10) are separated by a fourth distance different from the third distance. The second calculation step of acquiring the voltage value Vd of the fourth output signal of the magnetoelectric conversion element (20) that is output at the time and the selection step to the second acquisition step are performed a plurality of times, so that the first calculation step A data acquisition step of acquiring a data point between the voltage value V0 of the plurality of intersections calculated in the above and the difference Vd−Vc of the plurality of voltage values acquired in the second acquisition step corresponding to the voltage value V0 of the intersection; After the data acquisition process, the relationship between the data points is

The second calculation step for calculating the coefficients a and b is performed by approximation, and after the second calculation step, the measurement step and the adjustment step are performed by all the magnetic sensors (10) to be adjusted. Is good.

  According to this, the coefficients a and b are calculated before the adjustment (measurement step and adjustment step) of the plurality of magnetic sensors (10) to be adjusted.

  Although details will be described in the embodiment, in order to correct the temperature characteristic, the coefficient at the first temperature is performed by performing the selection step to the second calculation step at the first temperature as described in claim 4. a and b are calculated, and the coefficients a and b at the second temperature are calculated by performing the selection step to the second calculation step at a second temperature different from the first temperature. And as described in Claim 5, after performing a measurement process and an adjustment process at 1st temperature, a measurement process and an adjustment process are performed at 2nd temperature. According to this, in the measurement process and the adjustment process at the first temperature, offset correction (adjustment of the voltage level of the output signal of the magnetoelectric transducer (20)) is performed, and the measurement process and the adjustment at the second temperature. In the process, the temperature characteristic is corrected.

  Since the operational effects of the inventions according to claims 6 and 7 are the same as the operational effects of the inventions according to claims 1 and 2, the description thereof is omitted.

  In addition, as a control part (90) of Claim 7, as described in Claim 8, the control part (90) was arrange | positioned between the magnetic sensor (10) and the adjustment part (80). A configuration having a selection switch (91) and an opening / closing control unit (92) for controlling opening / closing of the selection switch (91) may be employed.

It is a top view which shows schematic structure of the magnetic sensor adjustment apparatus which concerns on 1st Embodiment. It is sectional drawing which shows schematic structure of a magnetic sensor. It is a block diagram which shows schematic structure of the magnetic sensor adjustment apparatus shown in FIG. It is a graph which shows the waveform signal of a magnetoelectric conversion element, (a) has shown room temperature, (b) has shown high temperature. It is a graph which shows the relationship between the voltage value V0 of an intersection, and the difference Vd-Vc of a voltage value, (a) has shown room temperature, (b) has shown high temperature. It is a block diagram which shows the modification of a magnetic sensor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a top view illustrating a schematic configuration of the magnetic sensor adjustment device according to the first embodiment. FIG. 2 is a cross-sectional view showing a schematic configuration of the magnetic sensor. FIG. 3 is a block diagram showing a schematic configuration of the magnetic sensor adjustment device shown in FIG. FIG. 4 is a graph showing the waveform signal of the magnetoelectric transducer, where (a) shows room temperature and (b) shows high temperature. FIG. 5 is a graph showing the relationship between the voltage value V0 at the intersection and the voltage value difference Vd−Vc, where (a) shows room temperature and (b) shows high temperature. The unit of the vertical axis and the horizontal axis in FIGS. 4 and 5 is an arbitrary unit.

  As shown in FIG. 1, the magnetic sensor adjustment device 100 moves, as a main part, a magnetic body 70 for changing the magnetic field formed by the magnet 30 of the magnetic sensor 10, and at least one of the magnetic sensor 10 and the magnetic body 70. A moving unit (not shown) for adjusting, and an adjusting unit 80 for adjusting the output characteristics of the magnetic sensor 10. The magnetic sensor adjustment device 100 according to the present embodiment includes a control unit 90 that controls electrical connection between the magnetic sensor 10 and the adjustment unit 80 in addition to the above components.

  Hereinafter, before describing the magnetic sensor adjusting device 100, the magnetic sensor 10 to be adjusted will be described with reference to FIGS. The magnetic sensor 10 detects a rotation state of a rotating body (not shown) having a plurality of teeth arranged on the surface. The magnetic sensor 10 includes a magnetoelectric conversion element 20 that converts a magnetic change into an electric signal, a magnet 30 that forms a magnetic field around the magnetoelectric conversion element 20, and a processing unit 40 that processes an output signal of the magnetoelectric conversion element 20. The terminal 50 for transmitting and receiving electrical signals between the processing unit 40 and the outside, and the pedestal 60 on which the terminal 50 is insert-molded and the magnetoelectric transducer 20 and the processing unit 40 are mounted. In the present embodiment, the magnetoelectric conversion element 20 and the processing unit 40 are mounted on one chip 11, and the chip 11 is mounted on the pedestal 60.

  The magnetoelectric conversion element 20 has a plurality of magnetoresistive effect elements 21 whose resistance changes according to the direction of application of magnetism. As shown in FIG. 2, two magnetoresistive elements 21 are arranged in a letter C, and as shown in FIG. 3, the two magnetoresistive elements 21 constitute a half bridge circuit. In the present embodiment, two half-bridge circuits described above are configured, and a full-bridge circuit is configured by these two half-bridge circuits. The midpoint of each of these two half bridge circuits is connected to the amplifier 41 of the processing unit 40.

  The magnet 30 is a cylindrical magnet, and the end on the magnetic body 70 side is magnetized to the N pole, and the opposite side is magnetized to the S pole. As shown in FIG. 2, the magnetoelectric conversion element 20 and the processing unit 40 are disposed in the hollow of the magnet 30, and the magnetoelectric conversion element 20 is surrounded by the N pole of the magnet 30. In general, the hollow magnet has a higher magnetic field stability than the hollow one. Therefore, in the case of the said structure, it is suppressed that the magnetic flux applied to the magnetoelectric conversion element 20 fluctuates rapidly.

  As illustrated in FIG. 3, the processing unit 40 includes an amplifier 41, a correction unit 42, a comparator 43, and an output buffer 44. The midpoints of the two half bridge circuits are connected to the input terminal of the amplifier 41, and the output terminal of the amplifier 41 is connected to the input terminal of the comparator 43. The input terminal of the correction unit 42 is connected to the wiring connecting the amplifier 41 and the comparator 43, and the output terminal of the comparator 43 is connected to the input terminal of the output buffer 44. Finally, the output terminal of the output buffer 44 is connected to the terminal of the chip 11 and is output to the outside (terminal 50).

  With the above connection configuration, the amplifier 41 differentially amplifies the output signal of the magnetoelectric conversion element 20, and the correction unit 42 corrects the offset and temperature characteristics of the differentially amplified output signal. The corrected output signal is binarized by the comparator 43 based on the threshold voltage Vth, and the binarized output signal is output to the terminal 50 via the output buffer 44. The comparator 43 corresponds to the signal processing unit described in the claims.

  The binarization processing is to divide a signal into two voltage levels (Lo level and Hi level) depending on whether the voltage value is larger or smaller than the threshold voltage Vth. Therefore, the output characteristics of the magnetic sensor 10 indicate not the voltage level but the timing at which the two voltage levels are switched. That is, the rising edge of the signal from the Lo level to the Hi level and the falling edge of the signal from the Hi level to the Lo level are shown.

  As shown in FIG. 3, the correction unit 42 includes an offset correction circuit 42a and a temperature correction circuit 42b. The offset correction circuit 42 a convolves the offset voltage Voff with the output signal of the amplifier 41, and the temperature correction circuit 42 b convolves the temperature special voltage Vt with the output signal of the amplifier 41. By doing so, offset and temperature characteristics are corrected. In addition, since the detailed structure of the components 41-44 of the process part 40 is known as shown, for example in Unexamined-Japanese-Patent No. 2004-301645, the description is omitted in this embodiment.

  The terminal 50 includes a ground terminal 51 that is electrically connected to the ground, an output terminal 52 that outputs the output signal of the magnetoelectric transducer 20 via the processing unit 40 to the outside, and a power terminal that is electrically connected to the power source. 53.

  The pedestal 60 has a rectangular shape, the chip 11 (the magnetoelectric conversion element 20 and the processing unit 40) is mounted on the end of the magnet 30 on the N pole side, and the terminal 50 is insert-molded on the end of the S pole side. Yes. Although not shown, a wiring pattern is formed on the mounting surface of the chip 11, and the chip 11 and the wiring pattern, and the wiring pattern and the terminal 50 are electrically connected via a connecting member (not shown). . After the chip 11 is mounted on the pedestal 60 and the electrical connection between the chip 11 and the terminal 50 is completed, the pedestal 60 is inserted into the hollow of the magnet 30, and the pedestal 60 (magnetoelectric conversion element 20) and the magnet 30 are connected. The position is determined.

  Next, the magnetic sensor adjustment device 100 will be described. As described above, the magnetic sensor adjustment device 100 includes the magnetic body 70, the moving unit (not shown), the adjustment unit 80, and the control unit 90. As shown in FIG. 1, the magnetic body 70 has a rectangular shape and is perpendicular to the facing direction of the magnetic sensor 10 and the magnetic body 70 so that the plurality of magnetic sensors 10 face the main surface of the magnetic body 70. They are lined up in a direction. In the present embodiment, the magnetic body 70 is movable in the facing direction by the moving unit.

  The adjustment unit 80 includes a measurement unit (not shown) that measures the output signal of the magnetoelectric conversion element 20, a storage unit (not shown) that stores coefficients a and b, which will be described later, and a threshold voltage Vth, and the storage unit. The coefficients a and b are read out, the following equation 4 is calculated, a calculation unit (not shown) for calculating the difference between the calculation result and the threshold voltage Vth, and based on the calculation result of the calculation unit, the magnetic sensor 10 A rewriting unit (not shown) for rewriting the offset voltage Voff and the temperature special voltage Vt.

  The control unit 90 includes a selection switch 91 disposed between the magnetic sensor 10 and the adjustment unit 80, and an opening / closing control unit 92 that controls opening / closing of the selection switch 91. The opening / closing control unit 92 sequentially electrically connects one magnetic sensor 10 and the adjustment unit 80 by sequentially closing one selection switch 91 among the plurality of selection switches 91.

  Next, a magnetic sensor adjustment method according to this embodiment will be described. First, as shown in FIG. 1, the plurality of magnetic sensors 10 to be adjusted are electrically connected to the adjustment unit 80 via the selection switch 91 and are opposed to the magnetic body 70. Then, any one of the plurality of magnetic sensors 10 is electrically connected to the adjustment unit 80 by the opening / closing control unit 92. The above is the connection process.

  After the connection process, the relative distance between the magnetic sensor 10 and the magnetic body 70 is set to a distance (first distance) to which the magnetic field applied to the magnetoelectric conversion element 20 varies depending on the magnetic body 70. The voltage value Va of the output signal (first output signal) of the magnetoelectric conversion element 20 at the first distance is measured by the measuring unit of the adjusting unit 80. Next, by moving the magnetic body 70 closer to the magnetic sensor 10 by the moving unit, the relative distance between the magnetic sensor 10 and the magnetic body 70 is a second distance shorter than the first distance (the magnetic body 70 is indicated by a broken line in FIG. 1). Position). The voltage value Vb of the output signal (second output signal) of the magnetoelectric transducer 20 at the second distance is measured by the measuring unit. The above is the measurement process.

After the measurement process, the calculation unit of the adjustment unit 80 reads the coefficients a and b from the storage unit and calculates the following formula.

が成立するように磁電変換素子２０（アンプ４１）の出力信号の電圧レベルを調整する。以上が、調整工程である。上記した接続工程〜調整工程を、全ての磁気センサ１０にて行うことで、全ての磁気センサ１０の調整が終了となる。 Next, the calculation unit calculates the difference between the calculation result and the threshold voltage Vth. Based on the difference, the rewrite unit of the adjustment unit 80 rewrites the offset voltage Voff and the temperature special voltage Vt to obtain the following formula:

The voltage level of the output signal of the magnetoelectric conversion element 20 (amplifier 41) is adjusted so that is established. The above is the adjustment process. By performing the connection process to the adjustment process described above for all the magnetic sensors 10, the adjustment of all the magnetic sensors 10 is completed.

  In the present embodiment, the connection process to the adjustment process described above are performed in atmospheres having different temperatures, that is, room temperature and a temperature higher than room temperature. In this way, not only offset correction but also temperature characteristic correction is performed, which will be described later. Incidentally, the room temperature corresponds to the first temperature described in the claims, and the high temperature corresponds to the second temperature described in the claims.

  The above-described coefficients a and b are calculated through the following steps. Before performing the measurement process, one arbitrary magnetic sensor 10 is selected from among the plurality of magnetic sensors 10 to be adjusted. The above is the selection process.

  After the selection step, the selected magnetic sensor 10 and the rotating rotator are opposed to each other, and the relative distance between the selected magnetic sensor 10 and the rotator is changed at least twice by the moving unit. By doing so, the output signal (output waveform) of the magnetoelectric conversion element 20 between each relative distance is acquired. The above is the first acquisition step.

  After the first acquisition step, as shown in FIG. 4, the output waveforms of the magnetoelectric transducer 20 are matched to each other between the relative distances, and the output waveforms are overlapped. By doing so, the voltage value V0 of the intersection where each output waveform crosses is calculated. The above is the first calculation step. Note that the calculation of the voltage value V0 in the first calculation step is performed by the calculation unit. The vertical axis of FIG. 4 indicates the voltage of the output waveform of the magnetoelectric conversion element 20, and the horizontal axis indicates the phase of the output waveform (rotation angle of the rotating body).

  After the first calculation step, the selected magnetic sensor 10 and the magnetic body 70 are opposed to each other, and the relative distance between the magnetic sensor 10 and the magnetic body 70 is set as the third distance. The voltage value Vc of the output signal (third output signal) of the magnetoelectric transducer 20 at the third distance is acquired by the measuring unit of the adjusting unit 80. Next, the relative distance between the magnetic sensor 10 and the magnetic body 70 is set to a fourth distance shorter than the third distance by bringing the magnetic body 70 closer to the magnetic sensor 10 by the moving unit. The voltage value Vd of the output signal (fourth output signal) of the magnetoelectric transducer 20 at the fourth distance is acquired by the measurement unit. The above is the second acquisition step.

  In the present embodiment, the third distance is equal to the first distance, and the fourth distance is equal to the second distance. The difference between the first distance and the second distance is equal to the tooth length of the rotating body.

  By performing the selection step to the second acquisition step a plurality of times (for example, 8 times), the voltage values V0 of the plurality of intersections calculated in the first calculation step and the voltage values V0 of the intersections corresponding to the second A data point with a difference Vd−Vc between a plurality of voltage values acquired in the acquisition step is acquired. The above is the data acquisition process.

で近似することで、係数ａ，ｂを算出する。以上が、第２算出工程である。なお、データ取得工程でのデータ点の取得及び係数ａ，ｂの算出は、演算部にて行われ、算出された係数ａ，ｂは、記憶部に記憶される。図５の縦軸は交点の電圧値Ｖ０、横軸は電圧値の差分Ｖｄ−Ｖｃを示している。 After the data acquisition process, as shown in FIG.

To calculate the coefficients a and b. The above is the second calculation step. The acquisition of data points and the calculation of the coefficients a and b in the data acquisition process are performed by the calculation unit, and the calculated coefficients a and b are stored in the storage unit. In FIG. 5, the vertical axis represents the voltage value V0 at the intersection, and the horizontal axis represents the voltage value difference Vd−Vc.

  Through the above steps, the coefficients a and b are calculated before the adjustment (connection process to adjustment process) of the plurality of magnetic sensors 10 to be adjusted.

  In the present embodiment, in order to correct the temperature characteristics, the first acquisition process to the second calculation process are performed at room temperature and at a high temperature higher than room temperature. By doing so, not only the coefficients a1 and b1 at room temperature but also the coefficients a2 and b2 at high temperature are calculated.

  Next, adjustment of the voltage level of the output signal of the magnetoelectric conversion element 20 (amplifier 41) will be described in detail. In the adjustment step described above, the voltage level of the output signal of the magnetoelectric conversion element 20 (amplifier 41) so that Formula 5 is satisfied (so that the threshold voltage Vth and the voltage level of the voltage value represented by Formula 4 match). Was adjusted. In order to realize this, the offset voltage Voff is adjusted. Further, in order to adjust the temperature characteristic, the temperature special voltage Vt is adjusted.

  Hereinafter, offset correction and temperature characteristic correction will be described. First, the offset voltage Voff, temperature characteristic voltage Vt, and threshold voltage Vth of the magnetic sensor 10 to be adjusted are set to appropriate values. And voltage value Va1, Vb1 is measured at room temperature, and Numerical formula 4 is calculated based on coefficient a1, b1. Here, the difference between the appropriately adjusted threshold voltage Vth and the room temperature voltage value calculated by Equation 4 is taken. Based on this difference, the offset voltage Voff is determined, and the offset voltage Voff is rewritten (adjusted) by the rewriting unit of the adjusting unit 80. As a result, Formula 5 is established at room temperature.

  After adjusting the offset voltage Voff, the voltage values Va2 and Vb2 are measured at a high temperature, and Equation 4 is calculated based on the coefficients a2 and b2. Here, the difference between the offset-corrected threshold voltage Vth and the high-temperature voltage value calculated by Equation 4 is taken. Based on this difference, the temperature special voltage Vt is determined, and the temperature special voltage Vt is rewritten (adjusted) by the rewriting unit of the adjustment unit 80. As a result, Formula 5 holds even when the temperature changes.

  Next, the effect of the magnetic sensor adjustment method and the magnetic sensor adjustment device 100 according to the present embodiment will be described. As a result of investigation by the present inventor, the following points were found. The distance (detection gap length) between the rotating body and the magnetoelectric conversion element 20 is changed between a plurality of set values, and an output signal (waveform signal) of the magnetoelectric conversion element 20 is acquired for each set value of the detection gap length. Then, a voltage value V0 (voltage value independent of the detection gap length) of the intersection point between the signals when the plurality of acquired waveform signals are superimposed in the same phase is calculated. This was calculated by a plurality of magnetic sensors 10, and data points indicating the correlation with the output sensitivity (Vb-Va) of each magnetic sensor 10 were created. Then, when an approximate expression connecting the data points was created, it was found that V0 = α × ln (Vb−Va) + β (α and β are real numbers). According to this, after measuring the voltage values Va and Vb instead of the waveform signal of the magnetoelectric conversion element 20, the threshold voltage Vth is adjusted by adjusting the voltage level of the output signal of the magnetoelectric conversion element so that Formula 5 is satisfied. Can be set to a voltage value that does not depend on the detection gap length.

  In order to obtain the voltage values Va and Vb, it is only necessary to change the relative distance between the magnetic sensor 10 and the magnetic body 70 twice as described above. According to this, as the shape of the magnetic body 70, not a circle but a shape that facilitates the opposing arrangement with the plurality of magnetic sensors 10 to be adjusted can be selected. As a result, complicated adjustment of the magnetic sensor 10 is suppressed.

  In the present embodiment, the magnetic body 70 has a rectangular shape, and the plurality of magnetic sensors 10 face the main surface of the magnetic body 70 in a direction perpendicular to the facing direction of the magnetic sensor 10 and the magnetic body 70. They are lined up in a row. As described above, since the plurality of magnetic sensors 10 to be adjusted are arranged in a straight line, the adjustment of the magnetic sensor 10 may be complicated compared to a configuration in which the plurality of magnetic sensors 10 are arranged in an arc. It is suppressed.

  In the present embodiment, in the connection process, after any one of the plurality of magnetic sensors 10 is electrically connected to the adjustment unit 80, the measurement process and the adjustment process are performed. As described above, since the electrical connection between the magnetic sensor 10 and the adjusting unit 80 is controlled, the physique of the magnetic sensor adjusting device 100 is increased as compared with the configuration in which one adjusting unit 80 is provided in each magnetic sensor 10. Is suppressed.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In the present embodiment, an example in which the magnetoelectric conversion element 20 and the processing unit 40 are mounted on one chip 11 is shown. However, as shown in FIG. 6, a configuration in which the magnetoelectric conversion element 20 and the processing unit 40 are mounted on different chips 12 and 13 may be employed. FIG. 6 is a block diagram showing a modification of the magnetic sensor.

  In this embodiment, the example which performs each process at room temperature and high temperature was shown. Of course, the temperature at which each step is performed is not limited to the above example, and for example, it may be performed at room temperature or at a temperature lower than room temperature.

  In this embodiment, the example which the magnetic body 70 moves by a moving part was shown. However, in order to change the relative distance between the magnetic sensor 10 and the magnetic body 70, the present invention is not limited to the above example. For example, the magnetic sensor 10 may be moved by the moving unit, or both the magnetic body 70 and the magnetic sensor 10 may be moved.

DESCRIPTION OF SYMBOLS 10 ... Magnetic sensor 20 ... Magnetoelectric conversion element 21 ... Magnetoresistive effect element 30 ... Magnet 40 ... Adjustment part 42 ... Correction | amendment part 43 ... Comparator 70 ... Magnetic body 80 ... Adjustment unit 90 ... Control unit 100 ... Magnetic sensor adjustment device

Claims (8)

Signal processing for binarizing the output signal of the magnetoelectric conversion element (20), the magnet (30) that forms a magnetic field around the magnetoelectric conversion element (20), and the magnetoelectric conversion element (20) based on a threshold voltage A magnetic sensor adjustment method for adjusting an output characteristic of a magnetic sensor (10) having a section (43) and detecting a rotation state of a rotating body,
The magnetoelectric conversion element (20) output when the magnetic body (70) for changing the magnetic field formed by the magnet (30) and the magnetic sensor (10) are separated by a first distance. The voltage value Va of one output signal and the magnetoelectric conversion element (20) output when the magnetic body (70) and the magnetic sensor (10) are separated by a second distance different from the first distance. ) Measuring the voltage value Vb of the second output signal of
After the measurement step, if the coefficients relating to the output characteristics of the magnetoelectric conversion element (20) are a and b and the threshold voltage is Vth,

And adjusting the voltage level of the output signal of the magnetoelectric conversion element (20) so that the above is established. The magnetic sensor (10) and the magnetic body (70) are arranged in a row so that the plurality of magnetic sensors (10) face the main surface of the magnetic body (70) in a direction perpendicular to the facing direction of the magnetic body (70). Lined up,
Before performing the measurement step, an arbitrary one of the plurality of magnetic sensors (10) is electrically connected to an adjustment unit (80) that adjusts the voltage level of the output signal of the magnetoelectric transducer (20). Having a connection step to connect,
The magnetic sensor adjustment method according to claim 1, wherein the connection step to the adjustment step are performed by all the magnetic sensors. Before performing the measurement step, a selection step of arbitrarily selecting one magnetic sensor (10) from among the plurality of magnetic sensors (10) to be adjusted;
After the selection step, the selected magnetic sensor (10) and the rotating body in a rotating state are opposed to each other, and the relative distance between the selected magnetic sensor (10) and the rotating body is changed at least twice, A first acquisition step of acquiring an output signal of the magnetoelectric transducer (20) between relative distances;
After the first acquisition step, the phase of the output signal of the magnetoelectric transducer (20) between the relative distances is matched and the output signals are overlapped to calculate the voltage value V0 at the intersection where the output signals intersect. 1 calculation step;
After the first calculation step, when the selected magnetic sensor (10) and the magnetic body (70) are opposed to each other, and the magnetic body (70) and the magnetic sensor (10) are separated by a third distance. The voltage value Vc of the third output signal of the magnetoelectric conversion element (20) outputted to the magnetic field and the magnetic body (70) and the magnetic sensor (10) are separated by a fourth distance different from the third distance. A second acquisition step of acquiring a voltage value Vd of the fourth output signal of the magnetoelectric transducer (20) output when
By performing the selection step to the second acquisition step a plurality of times, the voltage value V0 of the plurality of intersections calculated in the first calculation step and the second acquisition step corresponding to the voltage value V0 of the intersections A data acquisition step of acquiring a data point with the difference Vd−Vc of the plurality of voltage values acquired in
After the data acquisition step, the relationship between the data points is

A second calculating step of calculating the coefficients a and b by approximating with
The magnetic sensor adjustment method according to claim 1 or 2, wherein after the second calculation step, the measurement step and the adjustment step are performed by all the magnetic sensors (10) to be adjusted.   The coefficients a and b at the first temperature are calculated by performing the selection step to the second calculation step at a first temperature, and the selection step to the second calculation at a second temperature different from the first temperature. The magnetic sensor adjustment method according to claim 3, wherein coefficients a and b at the second temperature are calculated by performing a step.   The magnetic sensor adjustment method according to claim 4, wherein after the measurement step and the adjustment step are performed at the first temperature, the measurement step and the adjustment step are performed at the second temperature. Signal processing for binarizing the output signal of the magnetoelectric conversion element (20), the magnet (30) that forms a magnetic field around the magnetoelectric conversion element (20), and the magnetoelectric conversion element (20) based on a threshold voltage A magnetic sensor adjusting device for adjusting an output characteristic of a magnetic sensor (10) having a portion (43) and detecting a rotation state of a rotating body,
A magnetic body (70) for varying the magnetic field formed by the magnet (30);
A moving unit that varies a relative distance between the magnetic body (70) and the magnetic sensor (10) by moving at least one of the magnetic body (70) and the magnetic sensor (10);
The voltage value Va of the first output signal of the magnetoelectric transducer (20) output when the magnetic body (70) and the magnetic sensor (10) are separated by a first distance, and the magnetic body (70) and the magnetic sensor (10) based on the voltage value Vb of the second output signal of the magnetoelectric transducer (20) output when the magnetic sensor (10) is separated by a second distance different from the first distance. And an adjustment unit (80) for adjusting the voltage level of the output signal of the magnetoelectric conversion element (20),
The adjustment unit (80) is represented by the following equation, where a and b are coefficients related to output characteristics of the magnetoelectric conversion element (20) and the threshold voltage is Vth.

The magnetic sensor adjustment device is characterized in that the voltage level of the output signal of the magnetoelectric transducer (20) is adjusted so that The magnetic sensor (10) and the magnetic body (70) are arranged in a row so that the plurality of magnetic sensors (10) face the main surface of the magnetic body (70) in a direction perpendicular to the facing direction of the magnetic body (70). Lined up,
A control unit (90) for controlling electrical connection between the magnetic sensor (10) and the adjustment unit (80);
The control unit (90) electrically connects any one of the plurality of magnetic sensors (10) to the adjustment unit (80), and the magnetic sensor selected by the adjustment unit (80). The adjustment of the voltage level of the output signal of the magnetoelectric conversion element (20) based on Va, Vb of (10) and the mathematical expression 3 is performed by all the magnetic sensors (10). 6. The magnetic sensor adjustment device according to 6.   The control unit (90) includes a selection switch (91) disposed between the magnetic sensor (10) and the adjustment unit (80), and an opening / closing control unit for controlling opening / closing of the selection switch (91). 92). The magnetic sensor adjustment device according to claim 7, further comprising:

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