JP2016045005A - Position detection sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position detection sensor capable of reducing decline of detection accuracy even if a fitting position has positional deviation.SOLUTION: A position detection sensor has a detector 3 for detecting a moving position of a moving body MB, and the detector 3 has a plurality of detection elements (13, 23). The plurality of detection elements (13, 23) are arranged in parallel in a direction along a moving direction (direction of movement MD) of the moving body MB. At least two of output signals from the plurality of detection elements (13, 23) are selected, and the position of the moving body MB is detected from the at least two output signals.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a position detection sensor for detecting a moving position of a moving body.

  In various devices equipped with a moving body such as an actuator, there is a demand in various scenes to detect the movement position of the moving body and know the movement in the various devices. For example, various position detection sensors are used to know the movement of a valve or piston of an internal combustion engine.

  As such a conventional example, Patent Document 1 (conventional example) proposes a detection apparatus 900 that detects the movement of a moving body that is a magnetic body. 10A and 10B are configuration diagrams for explaining a conventional detection device 900, in which FIG. 10A is a side view thereof and FIG. 10B is a perspective view thereof.

  A detection apparatus 900 shown in FIG. 10 is arranged with a rotating shaft 901, a magnetic rotating body (magnetic field change applying means) 902 that rotates in synchronization with the rotating shaft 901, and a predetermined gap from the magnetic rotating body 902. The giant magnetoresistive element 910 and a magnet (magnetic field generating means) 904 that applies a magnetic field to the giant magnetoresistive element 910 are configured. Further, as shown in FIG. 10B, the magnetic rotating body 902 has at least one unevenness, and the giant magnetoresistive element 910 has a magnetosensitive property as shown in FIG. 10B. A magnetoresistive pattern 910a and a magnetosensitive surface 910b are provided as patterns.

  When the magnetic rotator 902 rotates, the magnetic field with respect to the magnetosensitive surface 910b of the giant magnetoresistive element 910 changes, and the resistance value of the magnetoresistive pattern 910a changes. By detecting this change in resistance value, a predetermined position (angle) of the moving body that is the magnetic body rotating body 902 can be detected.

JP-A-9-311135

  However, when the giant magnetoresistive element 910 in the detection device 900 of the conventional example is arranged with a predetermined gap from the magnetic rotator 902, the position of the unevenness of the magnetic rotator 902 (see FIG. 10B). As a result, a relative displacement between the magnetosensitive surface 910b of the giant magnetoresistive element 910 is necessarily generated. In such a case, there is a problem that the output value at the initial position from the giant magnetoresistive element 910 may fluctuate with respect to a predetermined value due to positional deviation, and it is difficult to detect the position with high accuracy. .

  The present invention solves the above-described problems, and an object of the present invention is to provide a position detection sensor that can reduce a decrease in detection accuracy even if the mounting position is misaligned.

  In order to solve this problem, a position detection sensor of the present invention is a position detection sensor having a detection unit for detecting a position where a moving body has moved, wherein the detection unit includes a plurality of detection elements, Are arranged in parallel in a direction along which the moving body moves, and at least two output signals from the plurality of detection elements are selected, and the position of the moving body is determined from the at least two output signals. It is characterized by detecting.

  According to this, the position detection sensor of the present invention selects an output signal from an appropriate detection element corresponding to the position shift, even if the position detection sensor has a position shift with respect to the moving object. The position of the moving body can be detected from the output signal of the detection element. As a result, a decrease in detection accuracy can be reduced.

  In the position detection sensor of the present invention, the plurality of detection elements are a plurality of magnetoresistive effect elements that detect a change in a magnetic field accompanying the movement of the moving body, and the plurality of magnetoresistive effect elements move the moving body. A first magnetoresistive element whose sensitivity axis is in a first direction along the direction, and a second magnetoresistive element whose sensitivity axis is in a second direction opposite to the first direction. Forming a first detection element group in which a plurality of the first magnetoresistance effect elements are arranged side by side and a second detection element group in which a plurality of the second magnetoresistance effect elements are arranged side by side; The group and the second detection element group are arranged side by side in a direction along the moving direction of the moving body.

  According to this, the first magnetoresistive element whose sensitivity axis is oriented in the first direction along the moving direction of the moving body, and the second magnetoresistive whose sensitivity axis is oriented in the second direction opposite to the first direction. Therefore, the output signal from the first magnetoresistive effect element and the output signal from the second magnetoresistive effect element are output signals having behaviors opposite to the movement of the moving object. Therefore, the detection accuracy can be improved. Further, a first detection element group in which a plurality of first magnetoresistive elements are arranged in parallel and a second detection element group in which a plurality of second magnetoresistive elements are arranged in parallel are arranged in a direction along the moving direction of the moving body. Therefore, even if there is a slight misalignment in the mounting position of the position detection sensor, it is selected from the output signal from the first detection element group and the output signal from the second detection element group. By detecting the position, a decrease in detection accuracy can be further reduced.

  In addition, the position detection sensor of the present invention includes a bias magnet that applies a magnetic field in a direction orthogonal to the first direction and the second direction, and a magnetic boundary position of the magnetic field by the bias magnet is detected in the first detection. The bias magnet is arranged so as to coincide with a boundary position of a region where the element group and the second detection element group are respectively arranged.

  According to this, since the bias magnet for applying a bias magnetic field to the first magnetoresistive effect element and the second magnetoresistive effect element is provided, adverse effects on the first magnetoresistive effect element and the second magnetoresistive effect element due to the external magnetic field are provided. Can be reduced. Further, since the magnetic boundary position of the bias magnet coincides with the boundary position between the first detection element group and the second detection element group, it is equally divided with respect to the first detection element group and the second detection. A bias magnetic field can be applied. From these things, detection accuracy can be improved.

  In the position detection sensor of the present invention, one of the at least two selected output signals is the first magnetoresistive element, and the other is the second magnetoresistive element, A bridge circuit is formed by the first magnetoresistive effect element and the second magnetoresistive effect element corresponding to at least two selected output signals.

  According to this, since the bridge circuit is formed, an intermediate output signal can be used, and the first magnetoresistive effect element and the second magnetoresistive effect element having different sensitivity axes are used. , The output change becomes larger. As a result, the detection accuracy can be further improved.

  In the position detection sensor of the present invention, the detection unit includes a control unit to which the output signals of the plurality of detection elements are input, and the control unit outputs the output signals from the plurality of detection elements. The output values from the at least two detection elements are selected by comparing the respective output values.

  According to this, it is possible to select an optimal detection element corresponding to the situation where the moving body and the detection unit are located. Thereby, detection accuracy can be further improved.

  The position detection sensor of the present invention selects an output signal from an appropriate detection element corresponding to the position shift, and outputs the detection element even if there is a position shift in the mounting position of the position detection sensor with respect to the moving object. The position of the moving object can be detected by the signal. As a result, a decrease in detection accuracy can be reduced.

It is a figure explaining the position detection sensor of 1st Embodiment of this invention, Comprising: It is a perspective view which shows the state by which the position detection sensor was arrange | positioned corresponding to the moving body of a detection target. It is a perspective view explaining the position detection sensor of a 1st embodiment of the present invention. It is a disassembled perspective view explaining the position detection sensor of 1st Embodiment of this invention. It is a figure explaining the position detection sensor of 1st Embodiment of this invention, Comprising: It is a top view of a detection part. It is a figure explaining the position detection sensor of 1st Embodiment of this invention, Comprising: It is a top view of a detection element. It is a figure explaining the position detection sensor of 1st Embodiment of this invention, Comprising: It is the schematic diagram which showed the magnetic field of the bias magnet in the part of the detection element shown in FIG. It is a figure explaining a position detection sensor of a 1st embodiment of the present invention, and is a circuit diagram showing an example of a bridge circuit using a plurality of detection elements. It is a schematic diagram explaining the detection method of the position detection sensor concerning 1st Embodiment of this invention. It is the graph which showed the example of an output in the position detection sensor of 1st Embodiment of this invention. It is a block diagram explaining the detection apparatus of a prior art example, Comprising: Fig.10 (a) is the side view, FIG.10 (b) is the perspective view.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram for explaining a position detection sensor 101 according to the first embodiment of the present invention, and is a perspective view showing a state in which the position detection sensor 101 is arranged corresponding to a moving object MB to be detected.

  First, as shown in FIG. 1, the position detection sensor 101 according to the first embodiment of the present invention is disposed and used in the vicinity of the moving body MB. Although not shown, the position detection sensor 101 is arranged corresponding to the moving body MB by, for example, fixing an external device to which the position detection sensor 101 is fixed at an appropriate position with respect to the moving body MB. Can be achieved easily.

  The moving body MB using the position detection sensor 101 according to the first embodiment of the present invention is a rotating body having a disk shape, as shown in FIG. 1, which is made of a soft magnetic material such as iron. . Further, the outer periphery of the moving body MB has a comb-teeth shape in which irregularities are regularly provided. When the irregularities move (rotate), the magnetic field by the bias magnet 7 to be described later changes. . The position detection sensor 101 detects the change in the magnetic field, and the position for specifying how much the moving body MB has moved, that is, the rotation angle due to the rotation, and the like can be detected. In addition, as shown in FIG. 1, the direction (namely, rotation direction) which the moving body MB moves is demonstrated as clockwise. Hereinafter, the direction in which the moving body MB moves is described as the moving direction MD.

  Next, the position detection sensor 101 according to the first embodiment of the present invention will be described in detail. FIG. 2 is a perspective view illustrating the position detection sensor 101 according to the first embodiment of the present invention. FIG. 3 is an exploded perspective view illustrating the position detection sensor 101 according to the first embodiment of the present invention. FIG. 4 is a plan view showing the detection unit 3. FIG. 5 is a plan view showing a plurality of detection elements in the detection unit 3. FIG. 6 is a schematic diagram showing the magnetic field of the bias magnet 7 in the detection element portion shown in FIG. The thick two-dot chain line in FIG. 6 is a schematic representation of the magnetic field flow RM. FIG. 7 is a circuit diagram showing an example of the bridge circuit BC1 using a plurality of detection elements.

  The position detection sensor 101 according to the first embodiment of the present invention has an appearance as shown in FIG. 2, and as shown in FIG. 3, a detection unit 3 that detects the position where the moving body MB has moved, and a bias that applies a magnetic field. And a magnet 7. In addition, the position detection sensor 101 of the first embodiment includes a case member C1 material and a cover member C2 that house the detection unit 3 and the bias magnet 7, and a wiring member H8 for taking out a signal from the detection unit 3. I have.

  First, as shown in FIG. 4, the detection unit 3 of the position detection sensor 101 includes a detection unit K3 having a plurality of detection elements, and a control unit S3 to which output signals from the plurality of detection elements are input. Configured. In that case, the moving body MB and the detection unit K3 are arranged to face each other. In addition, the detection unit 3 includes a circuit board P3 on which the detection unit K3 and the control unit S3 are mounted, and a lead terminal R3 electrically connected to the control unit S3. And the detection part K3, control part S3, and the circuit board P3 are packaged with the synthetic resin.

  The detection unit K3 of the detection unit 3 uses, as the detection element, a magnetoresistive effect element that detects a change in the magnetic field accompanying the movement of the moving body MB. As shown in FIG. A plurality of first magnetoresistive elements 13 whose sensitivity axes are oriented in the direction DR1 and second magnetoresistive elements 23 whose sensitivity axes are oriented in the second direction DR2 opposite to the first direction DR1 ( In FIG. 5, each has eight). A first detection element group G13 in which eight rectangular-shaped first magnetoresistive elements 13 are arranged in parallel, and a second detection element group G23 in which eight rectangular-patterned second magnetoresistive elements 23 are arranged in parallel. And form. In addition, the number of the 1st magnetoresistive effect element 13 and the 2nd magnetoresistive effect element 23 is not restricted to eight, It selects suitably.

  In the first embodiment of the present invention, as shown in FIG. 5, the first direction DR1 which is the direction of the sensitivity axis of the first magnetoresistive effect element 13, the direction in which the moving body MB moves (moving direction MD), The first detection element group G13 and the second detection element group G23 are arranged side by side in the direction along the movement direction MD. The moving direction (moving direction MD) of the moving object MB moves in the clockwise direction. However, since the moving object MB is sufficiently larger than the detection unit K3, the moving direction MD and the first direction DR1 and It can be said that it is substantially parallel to the second direction DR2.

  Further, as shown in FIG. 5, the detection portion K3 includes a first terminal portion 13T and a second terminal portion 23T provided on both ends of the first magnetoresistance effect element 13 and the second magnetoresistance effect element 23. Although not shown, the first terminal portion 13T and the second terminal portion 23T are electrically connected to the control unit S3 by bonding wires and wiring of the circuit board P3.

  Further, the magnetoresistive effect element (detection element) of the detection unit K3 uses a giant magnetoresistive effect (GMR) element, and although not shown in detail, a Ni substrate 93 is formed on a silicon substrate 93. (Nickel) Fe (iron) Cr (chromium) alloy or pinned magnetic layer pinned in a certain direction through a seed layer made of Cr, non-magnetic material layer such as Cu (copper), A free magnetic layer whose magnetization direction rotates in the direction of the external magnetic field and a cover layer such as Ta (tantalum) are laminated in this order. Further, for example, a sputtering film forming method is used for forming each layer.

  The control unit S3 of the detection unit 3 is configured using an integrated circuit (IC), and a first magnetoresistive effect element which is a detection element via the first terminal unit 13T and the second terminal unit 23T. 13 and the output signal of the 2nd magnetoresistive effect element 23 are input. Then, the control unit S3 compares the output values of the output signals from the plurality of first magnetoresistive elements 13 and the second magnetoresistive elements 23, and compares the first magnetoresistive elements 13 and the second magnetoresistive elements. At least two output signals from the effect element 23 are selected one by one. Thereby, the optimal detection element (the 1st magnetoresistive effect element 13 and the 2nd magnetoresistive effect element 23) can be selected corresponding to the condition where the moving body MB and the detection part 3 are located.

  In the first embodiment of the present invention, for example, as shown in FIG. 7, four detection elements are selected to form a bridge circuit BC1, and the position of the moving object MB is detected from these output signals. ing. Specifically, as shown in FIG. 7, the bridge circuit BC1 includes a first magnetoresistance effect element 13b and a first magnetoresistance effect element 13c having a sensitivity axis in the first direction DR1, and a sensitivity axis in the second direction DR2. And the second magnetoresistive effect element 23b and the second magnetoresistive effect element 23c. The first magnetoresistive effect element 13b and the second magnetoresistive effect element 23b are connected by the first connection part CS1, and the first magnetoresistive effect element 13c and the second magnetoresistive effect element 23c are connected by the second connection part CS2. The second magnetoresistive effect element 23b and the first magnetoresistive effect element 13c side are connected to a drive (Vdd shown in the figure), and the first magnetoresistive effect element 13b and the second magnetoresistive effect element 23c side are grounded. Connected to (GND shown in the figure), the bridge circuit BC1 is completed. Thereby, the output signals (S1 and S2 shown in the drawing) from the first connection part CS1 and the second connection part CS2 can be used, and the first magnetoresistive effect elements (13b, 13c) and the second magnetoresistive effect element (23b, 23c) are used, the output change can be made larger.

  In addition, the control unit S3 compares the output values of the output signals from the plurality of first magnetoresistive effect elements 13 and the second magnetoresistive effect elements 23, and the first magnetoresistive effect element 13 and the first magnetoresistive effect element 13 Since the two magnetoresistive effect elements 23 are selected, for example, the obtained output value can be handled by offsetting, or the cycle of the output signal (for example, increasing the positive ratio) can be changed. Thereby, suitable detection according to a situation can be made.

  The circuit board P3 of the detection unit 3 uses a commonly used printed wiring board. Moreover, the lead terminal R3 of the detection unit 3 uses a metal thin plate cut and plated with nickel or the like.

  Next, as shown in FIG. 3, the bias magnet 7 of the position detection sensor 101 has a cylindrical shape. Although not shown, the detection unit 3 is inserted into the hole 7h shown in FIG. 3 is arranged so as to cover the periphery of 3. The bias magnet 7 applies a magnetic field in a direction orthogonal to the first direction DR1 of the first magnetoresistive element 13 and the second direction DR2 of the second magnetoresistive element 23, as shown in FIG. , Have been dressed. Thereby, a permanent magnet (for example, a permanent magnet is used for the moving body MB) is not provided on the moving body MB side, and a soft magnetic body such as iron that can be easily processed can be used. Furthermore, since the bias magnet 7 is disposed so as to cover the periphery of the detection unit 3, adverse effects on the first magnetoresistive effect element 13 and the second magnetoresistive effect element 23 due to the external magnetic field can be reduced.

  In addition, as shown in FIG. 6, the bias magnet 7 has a bias magnet whose boundary position AIB between the area AA where the first detection element group G13 is arranged and the area BB where the second detection element group G23 is arranged. 7 are arranged so as to coincide with the magnetic boundary position MIS of the magnetic field by 7. Thereby, a bias magnetic field can be equally applied to the first detection element group G13 and the second detection element group G23, and an accurate output can be obtained from the first magnetoresistance effect element 13 and the second magnetoresistance effect element 23. The difference between values can be obtained. The magnetic boundary position MIS here indicates the vicinity of the center position of the hole 7h of the bias magnet 7, and for example, a plane on which the first detection element group G13 and the second detection element group G23 exist is cut out. In this case, an intermediate position where the direction of the magnetic field is divided into left and right is set as a magnetic boundary position MIS. Although not shown in detail, by providing a holder on the wiring member H8 and fitting the holder into the hole 7h of the bias magnet 7, the detection unit 3 is arranged at the center of the hole 7h. I have to.

  Next, the case member C1 and the cover member C2 of the position detection sensor 101 are made by injection molding synthetic resin such as ABS resin (ABS, acrylonitrile butadiene styrene copolymer), as shown in FIGS. The detector 3 and the bias magnet 7 are housed in the housing C12s (see FIG. 3).

  Finally, the wiring member H8 of the position detection sensor 101 uses a wire covered with an insulating covering material, and one end side is connected to the lead terminal R3 of the detection unit 3 as shown in FIG. The other end of the wiring member H8 is connected to an external device that uses the position detection sensor 101, although not shown.

  Next, an example of the detection method and result of the position detection sensor 101 according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a schematic diagram for explaining a detection method of the position detection sensor 101 according to the first embodiment of the present invention. FIG. 8A shows a detection unit K3 of the detection unit 3 having a convex portion Mta of the moving body MB. 8 (b) shows a state (P2) in which the moving body MB has moved (rotated) slightly from the state of FIG. 8 (a), and FIG. 8 (c) Further, the moving body MB moves and the detection unit K3 faces the concave portion Mua of the moving body MB (P3), and FIG. 8D shows the moving body MB slightly moved (rotated) from the state of FIG. 8E shows a state (P5) in which the moving body MB further moves and the detection unit K3 faces the convex portion Mtb of the moving body MB. FIG. 9 is a graph showing an output example of the result in the position detection sensor 101 according to the first embodiment of the present invention. The vertical axis in FIG. 9 indicates output signals (voltages) from the first connection part CS1 and the second connection part CS2 shown in FIG. 7, and the horizontal axis indicates the distance that the moving object MB has moved. Further, the output value V1 and the output value V2 in FIG. 9 correspond to S1 and S2 shown in FIG. 7, and PD1 to PD5 in FIG. 9 correspond to the state changing from P1 to P5 shown in FIG. Yes.

  In the position detection sensor 101 according to the first embodiment of the present invention, first, in the state (P1) shown in FIG. 8A, the direction of the magnetic field by the bias magnet 7 and the first magnetoresistive effect element 13 ( 13b, 13c) and the second direction DR2 of the second magnetoresistance effect element 23 (23b, 23c) are orthogonal to each other (see FIG. 6), the first magnetoresistance effect element 13 and the second magnetoresistance effect element 13 There is no difference in the magnetic field received by the magnetoresistive element 23. As a result, as shown in FIG. 9, the output value at that time is the midpoint VM (the position of PD1 shown in FIG. 9) for both the output value V1 and the output value V2, and shows the same value. Conversely, in the first embodiment of the present invention, the first magnetoresistive effect element 13b and the first magnetoresistive effect element 13c are appropriately selected from the eight first magnetoresistive effect elements 13 so as to have the same value. The second magnetoresistive effect element 23b and the second magnetoresistive effect element 23c are appropriately selected from the eight second magnetoresistive effect elements 23. Thus, at least two (4 in the first embodiment) output signals of a plurality (16 in the first embodiment) of the detection elements (first magnetoresistive element 13 and second magnetoresistive element 23) are output. By selecting an appropriate number, it is possible to determine an output signal corresponding to the position shift and select an appropriate detection element even if there is a position shift at the mounting position of the position detection sensor 101. Needless to say, an appropriate detection element is selected each time depending on the mounting position of the position detection sensor 101.

  Next, when the convex portion Mta of the moving body MB moves from the state (P1) shown in FIG. 8A in the movement direction MD to the state (P2) shown in FIG. 8B, the direction of the magnetic field by the bias magnet 7 Will be biased toward the convex portion Mta moved in the movement direction MD. For this reason, the strength of the magnetic field in the first direction DR1 received by the first magnetoresistance effect element 13 (13b, 13c) is increased, and conversely, the second direction DR2 received by the second magnetoresistance effect element 23 (23b, 23c). The strength of the magnetic field is reduced. Then, the resistance value of the first magnetoresistance effect element 13 (13b, 13c) decreases, while the resistance value of the second magnetoresistance effect element 23 (23b, 23c) increases. As a result, as shown in FIG. 9, the output value V1 decreases from the midpoint VM and the output value V2 increases from the midpoint VM as shown in FIG. ), The output value V1 is minimized and the output value V2 is maximized.

  Further, when the convex portion Mta of the moving body MB moves in the movement direction MD, the strength of the magnetic field in the first direction DR1 received by the first magnetoresistive effect element 13 (13b, 13c) decreases conversely, while the second magnetoresistance The intensity of the magnetic field in the second direction DR2 received by the effect element 23 (23b, 23c) is increased. In the state (P3) shown in FIG. 8C, the detection unit K3 faces the concave portion Mua of the moving body MB, so that the influence of the magnetic field by the bias magnet 7 causes the first magnetoresistive element 13 and the second magnetic element The same applies to both the resistive effect elements 23. As a result, as shown in FIG. 9, the output value at that time is the middle point VM (position of PD3 shown in FIG. 9) for both the output value V1 and the output value V2, and shows the same value.

  Furthermore, when the convex portion Mta of the moving body MB moves from the state (P3) shown in FIG. 8C in the movement direction MD to the state (P4) shown in FIG. 8D, the direction of the magnetic field by the bias magnet 7 changes. It will be biased toward the convex portion Mtb that has moved. For this reason, the intensity of the magnetic field in the first direction DR1 received by the first magnetoresistive element 13 (13b, 13c) is further reduced, and conversely, the second direction received by the second magnetoresistive element 23 (23b, 23c). The strength of the DR2 magnetic field increases. Then, the resistance value of the first magnetoresistance effect element 13 (13b, 13c) increases, while the resistance value of the second magnetoresistance effect element 23 (23b, 23c) decreases. As a result, as shown in FIG. 9, the output value V1 increases from the midpoint VM and the output value V2 decreases from the midpoint VM as shown in FIG. ), The output value V1 is maximized and the output value V2 is minimized.

  Finally, when the convex portion Mta of the moving body MB moves in the movement direction MD, the strength of the magnetic field in the first direction DR1 received by the first magnetoresistance effect element 13 (13b, 13c) increases conversely, while the second magnetic field The strength of the magnetic field in the second direction DR2 received by the resistance effect element 23 (23b, 23c) decreases. In the state (P5) shown in FIG. 8 (e), the detection unit K3 faces the convex portion Mtb of the moving body MB, and the influence of the magnetic field by the bias magnet 7 causes the first magnetoresistive element 13 and the second magnetic element. The same applies to both the resistive effect elements 23. As a result, as shown in FIG. 9, the output value at that time is the middle point VM (position of PD5 shown in FIG. 9) for both the output value V1 and the output value V2, and shows the same value.

  In the position detection sensor 101 according to the first embodiment of the present invention, the output value V1 and the output value V2 obtained in this way are used as output values for detecting the position of the moving object MB. Thus, the first magnetoresistance effect element 13 whose sensitivity axis is oriented in the first direction DR1 along the moving direction (movement direction MD) of the moving body MB, and the sensitivity axis in the second direction DR2 opposite to the first direction DR1. Therefore, the output signal from the first magnetoresistive effect element 13 and the output signal having the opposite behavior from the second magnetoresistive effect element 23 are used. It will be. For this reason, the position of the moving object MB can be detected with a larger difference between output values, and the detection accuracy can be improved.

  Furthermore, in the position detection sensor 101 according to the first embodiment of the present invention, the first detection element group G13 includes a plurality of the first magnetoresistance effect elements 13 arranged side by side (the first magnetoresistance effect element 13b and the first magnetic resistance effect element 13). Two of the second detection element group G23 (second magnetoresistance effect element 23b and second magnetoresistance effect element 23c) are appropriately selected from the resistance effect element 13c) and the second magnetoresistance effect element 23 arranged in parallel. Thus, the position of the moving object MB is detected. For this reason, even if there is a slight positional deviation in the mounting position of the position detection sensor 101, the position of the moving body MB can be accurately detected.

  The effects of the position detection sensor 101 according to the first embodiment of the present invention configured as described above will be collectively described below.

  In the position detection sensor 101 according to the first embodiment of the present invention, the position displacement of the position detection sensor 101 with respect to the moving object MB is shifted by appropriately selecting at least two of the output signals of the plurality of detection elements. Even if there is, it is possible to select an output signal from an appropriate detection element corresponding to the positional deviation, and to detect the position of the moving body MB by using the output signal of the detection element. As a result, a decrease in detection accuracy can be reduced.

  The sensitivity axis is in the first magnetoresistance effect element 13 whose sensitivity axis is in the first direction DR1 along the moving direction (movement direction MD), and in the second direction DR2 opposite to the first direction DR1. The output signal from the first magnetoresistive effect element 13 and the output signal from the second magnetoresistive effect element 23 are caused by the movement of the moving body MB. On the other hand, the output signal has the opposite behavior. For this reason, it is possible to improve detection accuracy by judging from these output signals.

  Furthermore, the first detection element group G13 in which a plurality of first magnetoresistance effect elements 13 are arranged in parallel and the second detection element group G23 in which a plurality of second magnetoresistance effect elements 23 are arranged in parallel move in the direction in which the moving body MB moves ( Since the position detection sensor 101 is slightly attached to the mounting position of the position detection sensor 101, the output signal from the first detection element group G13 and the second detection are detected. The position of the moving object MB can be detected by selecting from the output signal from the element group G23. For this reason, the fall of detection accuracy can be reduced more.

  In addition, since the bias magnet 7 for applying a bias magnetic field to the first magnetoresistive effect element 13 and the second magnetoresistive effect element 23 is provided, the first magnetoresistive effect element 13 and the second magnetoresistive effect element 23 caused by an external magnetic field are provided. The adverse effect of can be reduced. Further, since the magnetic boundary position MIS of the bias magnet 7 coincides with the boundary position AIB between the first detection element group G13 and the second detection element group G23, the first detection element group G13 and the second detection element group are detected. A bias magnetic field can be equally applied to the element group G23. From these things, detection accuracy can be improved.

  Further, since the bridge circuit BC1 is formed, an intermediate output signal can be used, and the first magnetoresistive element 13 and the second magnetoresistive element 23 having different sensitivity axes are used. , The output change becomes larger. As a result, the detection accuracy can be further improved.

  Further, the control unit S3 compares the output values of the output signals from the plurality of detection elements and selects the output signals from at least two detection elements, so that the moving body MB and the detection unit 3 are located. Correspondingly, an optimal detection element can be selected. Thereby, detection accuracy can be further improved.

  In addition, this invention is not limited to the said embodiment, For example, it can deform | transform and implement as follows, These embodiments also belong to the technical scope of this invention.

<Modification 1>
In the first embodiment, the detection unit K3 and the control unit S3 are mounted on the circuit board P3 and packaged with a synthetic resin to form the detection unit 3. However, the present invention is not limited to this configuration. A configuration in which the part S3 is provided may be used.

<Modification 2>
In the first embodiment, the bias magnet 7 is preferably used. However, a configuration in which the bias magnet 7 is not used may be used. In that case, it is necessary to provide a permanent magnet or the like on the moving body MB side and to have a function of changing the magnetic field as the moving body MB moves.

<Modification 3>
In the first embodiment, the first magnetoresistive effect element 13b, the first magnetoresistive effect element 13c, the second magnetoresistive effect element 23b, and the second magnetoresistive effect element 23c constitute the bridge circuit BC1 (full bridge circuit). Although configured, the present invention is not limited to this. For example, the first magnetoresistive effect element 13 and the second magnetoresistive effect element 23 may be selected and a half bridge circuit may be used. Further, for example, four first magnetoresistive elements 13 and two second magnetoresistive elements 23 may be selected, and two full bridge circuits may be used. If two full bridge circuits are used, a more accurate position of the moving object MB can be detected.

<Modification 4>
In the first embodiment, a magnetoresistive effect element is suitably used as the detection element, but a Hall element or the like may be used instead. In addition, a giant magnetoresistive element (GMR element) is used as the magnetoresistive element, but an AMR (Anisotropic Magneto Resistive) element, a TMR (Tunnel Magneto Resistive) element, or the like may be used.

<Modification 5>
In the first embodiment, the rotating body is used as the moving body MB. However, the rotating body is not limited to this, and may be a moving body that moves linearly, for example.

  The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the scope of the object of the present invention.

3 detection unit 13, 13b, 13c first magnetoresistance effect element G13 first detection element group 23, 23b, 23c second magnetoresistance effect element G23 second detection element group S3 control unit 7 bias magnet MB moving body BC1 bridge circuit AA area (Area where the first detection element group is arranged)
BB region (region where the second detection element group is arranged)
AIB boundary position (area boundary position)
MIS boundary position (magnetic boundary position)
DR1 First direction DR2 Second direction MD Movement direction (direction in which the moving object moves)
101 Position detection sensor

Claims (5)

In the position detection sensor having a detection unit for detecting the position where the moving body has moved,
The detection unit has a plurality of detection elements,
The plurality of detection elements are arranged side by side in a direction along the moving direction of the moving body,
A position detection sensor, wherein at least two output signals from the plurality of detection elements are selected, and the position of the moving body is detected from the at least two output signals. The plurality of detection elements are a plurality of magnetoresistance effect elements that detect a change in a magnetic field accompanying the movement of the moving body,
The plurality of magnetoresistive elements have a first magnetoresistive element whose sensitivity axis is oriented in a first direction along the moving direction of the moving body, and a sensitivity axis is oriented in a second direction opposite to the first direction. A second magnetoresistive effect element,
Forming a first detection element group in which a plurality of the first magnetoresistance effect elements are arranged in parallel, and a second detection element group in which a plurality of the second magnetoresistance effect elements are arranged in parallel;
The position detection sensor according to claim 1, wherein the first detection element group and the second detection element group are arranged side by side in a direction along a moving direction of the moving body. A bias magnet that applies a magnetic field in a direction perpendicular to the first direction and the second direction;
The bias magnet is arranged so that the magnetic boundary position of the magnetic field by the bias magnet coincides with the boundary position of the region where the first detection element group and the second detection element group are respectively arranged. The position detection sensor according to claim 2. One of the at least two selected output signals is the first magnetoresistive element, and the other is the second magnetoresistive element,
4. The bridge circuit is formed by the first magnetoresistive element and the second magnetoresistive element corresponding to the at least two selected output signals. 5. Position detection sensor. The detection unit includes a control unit to which the output signals of the plurality of detection elements are input,
5. The control unit compares output values of the output signals from the plurality of detection elements, and selects output signals from the at least two detection elements. The position detection sensor according to any one of the above.