JP2012018157A - Position sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position sensor that can enhance the linearity of impedance variations of a detection coil with respect to displacement of an object.SOLUTION: A position sensor comprises: detection coils Co arranged opposite to detection bodies 30a and 30b which move, interlocked with displacement of the object, on a circular track and formed on the surfaces of respective dielectric substrates 1 and 2 by printing; and a detecting section that detects any displacement of the object on the basis of inductance (impedance) of the detection coils Co varying in response to the displacement of the detection bodies 30a and 30b. The respective detection coils of the respective dielectric substrates 1 and 2 are configured of a plurality of first turns a0 and b0 so wound as to surround gaps g of a prescribed length in the displacement direction of the detection bodies 30a and 30b and two pairs of second turns a1 and a2, and b1 and b2 so wound folded back as to cross the gaps g.

Description

  The present invention relates to a position sensor that detects displacement of an object.

Conventionally, various position sensors for detecting displacement of an object (for example, a rotation amount or a rotation angle or a rotation position of a rotating object) have been provided. For example, those disclosed in Patent Document 1 are available. is there. The displacement sensor (position sensor) described in Patent Document 1 includes a detection coil wound around a cylindrical core made of a non-magnetic material, and an inner side or an outer side of the detection coil, and is arranged in the axial direction of the detection coil. A displaceable cylindrical conductor. Then, an oscillation signal having a frequency corresponding to the inductance of the detection coil that changes in accordance with the distance between the detection coil and the conductor is output from the oscillation circuit, and the displacement of the conductor is detected based on the oscillation signal. Thus, the displacement of the object can be detected by detecting the displacement of the conductor linked to the object as the inductance change of the detection coil.

  However, in the position sensor described in Patent Document 1, since the core has to be inserted into the conductor, the thickness dimension of the case for storing the conductor and the core is increased, and it is difficult to reduce the thickness. was there. Therefore, in recent years, position sensors that can solve the above problems have been considered. Hereinafter, this position sensor will be described with reference to the drawings. In the following description, the vertical direction in FIG. 5 is defined as the vertical direction.

  As shown in FIG. 5, this position sensor has a first insulating substrate 100 printed with a pair of detection coils 100a on the upper surface and a pair of detection coils (not shown) printed on the lower surface. A second insulating substrate 101. Moreover, the rotor block 104 which has a pair of detection body 102a formed in the sector shape from the nonmagnetic material and the holding body 103 holding each detection body 102a is provided. The first and second insulating substrates 100 and 101 and the rotor block 104 are accommodated in a case 105 formed by closing an opening surface of a box body 105a having one surface opened by a cover 105b. Strictly speaking, the shape of the detection body 102a is not a fan shape, but is a shape equal to the remaining figure obtained by cutting out a similar fan shape that is slightly smaller than the fan shape. Therefore, in the following description, all the “sectors” refer to “remaining graphics obtained by cutting out a similar sector shape slightly smaller than the sector shape”.

  Hereinafter, the operation of the position sensor will be briefly described. When the holding body 103 of the rotor block 104 interlocked with the object rotates in accordance with the displacement of the object (not shown), the detection bodies 102a are displaced from each other by 180 degrees in conjunction with the holding body 103, and the circumferential trajectory. Displace the top. Similarly to the conventional example described in Patent Document 1, an oscillation signal having a frequency corresponding to the inductance of each detection coil that changes in accordance with the relative position between each detection body 102a and the two detection coils is set as an oscillation circuit. Output from. By detecting the displacement of each detection body 102a based on this oscillation signal, it is possible to detect the relative position information between each detection body 102a and the detection coil, that is, the amount of rotation of the object interlocked with the rotor block 104. . Since a specific detection method is conventionally known as disclosed in Patent Document 1, detailed description thereof is omitted here.

JP 2008-292376 A

  By the way, in the position sensor as described above, the change rate of the inductance (impedance) of the detection coil with respect to the displacement of the object is constant, that is, the impedance of the detection coil may change linearly with respect to the displacement of the object. preferable. However, in the latter conventional example, the path of the eddy current flowing through each detection body 102a changes with the displacement of each detection body 102a, and the current density varies depending on the location. It changes nonlinearly with respect to the displacement of 102a. For this reason, since the impedance of the detection coil changes nonlinearly even with respect to the displacement of the object, there is a problem that sufficient linearity cannot be obtained.

  The present invention has been made in view of the above points, and an object thereof is to provide a position sensor that can improve the linearity of a change in impedance of a detection coil with respect to the displacement of an object.

  The position sensor of the present invention is disposed opposite to a detection body that is displaced on a predetermined trajectory in conjunction with the displacement of an object, and a detection coil formed on the surface of a substrate made of a dielectric, and the detection A detection unit that detects the displacement of the object based on the impedance of the detection coil that changes according to the displacement of the body, and the detection coil has a predetermined length dimension along the displacement direction of the detection body. It is characterized by comprising a plurality of first turns wound around the gap and at least one or more second turns wound back around the gap.

  In this position sensor, the substrate is formed of a multilayer substrate, and the detection coils are formed in the respective layers, and the second turn of each of the detection coils of at least two layers among the layers is respectively in the thickness direction of the substrate. It is preferable that they are arranged so as not to overlap each other.

  The position sensor preferably includes the detection body.

  According to the present invention, the change in the impedance of the detection coil with respect to the displacement of the detection body can be approximated linearly by changing the magnetic flux density in a step shape at the turn-back portion of the second turn of the detection coil. Therefore, it is possible to improve the linearity of the change in the impedance of the detection coil with respect to the displacement of the object interlocked with the displacement of the detection body.

2A and 2B are views showing an embodiment of a position sensor according to the present invention, wherein FIG. 1A is an exploded perspective view, and FIG. 2B is a top view of a first dielectric substrate. It is a correlation diagram which shows the characteristic of the change of the inductance with respect to the rotation angle of a target object same as the above. It is a figure which shows another structure same as the above, (a) is a top view of a 1st dielectric substrate, (b) is a correlation diagram which shows the characteristic of the change of the inductance with respect to the rotation angle of a target object. It is a figure which shows the structure of a linear motion type position sensor same as the above, (a) is a schematic diagram, (b) is a top view of the detection coil which consists only of a 1st turn, (c) is a 1st turn and It is a top view of the detection coil which consists of a 2nd turn. It is a disassembled perspective view which shows the conventional position sensor.

  Embodiments of a position sensor according to the present invention will be described below with reference to the drawings. In the following description, the vertical and horizontal directions and the front and rear directions are defined in FIG. Further, in the following description, when referred to as “detection coil Co”, all of the detection coils 10a and 10b of the first dielectric substrate 1 and the detection coils of the second dielectric substrate 2 described later are all referred to. Shall point to. In the present embodiment, as shown in FIG. 1A, a first dielectric substrate 1 having a pair of detection coils 10a and 10b printed on the upper surface and a pair of detection coils (not shown) on the lower surface. ) Is printed and formed on the second dielectric substrate 2. The rotor block 3 includes a pair of detection bodies 30a and 30b formed in a sector shape from a nonmagnetic material (for example, an aluminum plate) and a holding body 31 that holds the detection bodies 30a and 30b. The first and second dielectric substrates 1 and 2 and the rotor block 3 are accommodated in a case 6 formed by closing an opening surface of a box body 4 whose upper surface is opened by a cover 5.

  The first dielectric substrate 1 is formed in a disk shape, and a circular through hole 11 is provided in the center of the first dielectric substrate 1 so as to penetrate in the thickness direction. The pair of detection coils 10a and 10b are printed on the upper surface of the first dielectric substrate 1 at positions facing each other with the through hole 11 therebetween. The pair of detection coils 10a and 10b are patterned so that the outer shape thereof is a fan shape. Further, on the outer peripheral edge of the first dielectric substrate 1, a plurality of (not shown in the figure) notches 12 having a relatively narrow width and a plurality of notches (not shown in the figure) having a relatively large width (three in the figure) are provided. 13 are provided at equal intervals and alternately. Furthermore, four through holes 14 are arranged in parallel along the circumferential direction at the rear end of the first dielectric substrate 1. Lands (not shown) that are electrically connected to the coil terminals of the detection coils 10 a and 10 b are printed on the open ends of the through holes 14 on the lower surface of the first dielectric substrate 1.

  The second dielectric substrate 2 has a main piece 20 formed in a disc shape and provided with a circular through hole 21 penetrating in the thickness direction in the center portion, and a rectangular protruding from the outer peripheral edge on the rear side of the main piece 21. The terminal piece 22 having a shape is integrally formed. A pair of detection coils are printed on the lower surface of the second dielectric substrate 2 at positions facing each other with the through hole 21 therebetween. Although not shown, the pair of detection coils are formed in the same shape and the same dimensions as the detection coils 10 a and 10 b of the first dielectric substrate 1. Further, a plurality of narrow (not shown in the figure) notches 23 are provided at equal intervals on the outer peripheral edge of the second dielectric substrate 2. Further, four through holes 24 are arranged in parallel along the circumferential direction at the rear end portion (connecting portion with the terminal piece 22) of the main piece 20, and the four through holes 25 are also provided in the terminal piece 22 in the left-right direction. Along the line. On the upper surface of the second dielectric substrate 2, lands (not shown) electrically connected to the coil terminals of the respective detection coils on the lower surface are printed at the opening ends of the respective through holes 24. Then, four lands (not shown) that are electrically connected to the four lands by a conductive pattern (not shown) are printed at the open ends of the through holes 25 of the terminal pieces 22.

  Here, one detection coil 10a formed on the first dielectric substrate 1 and one detection coil (one facing the detection coil 10a in the vertical direction) formed on the second dielectric substrate 2; Are electrically connected via a terminal block 7. Similarly, the other detection coil 10b formed on the first dielectric substrate 1 and the other detection coil (the one facing the detection coil 10b in the vertical direction) formed on the second dielectric substrate 2; Are electrically connected via a terminal block 7. The terminal block 7 includes four terminal pins 70 and an insulator 71 that holds each terminal pin 70 at a central portion. The lower end portions of the terminal pins 70 are inserted into the four through holes 14 of the first dielectric substrate 1 and soldered to the lands on the lower surface of the first dielectric substrate 1. Further, the upper end portions of the terminal pins 70 are respectively inserted into the four through holes 24 of the second dielectric substrate 2 and soldered to lands on the upper surface of the second dielectric substrate 2. That is, the coil terminals of the detection coils 10a and 10b on the first dielectric substrate 1 side and the coil terminals of the detection coil on the second dielectric substrate 2 side are electrically connected via the four terminal pins 70. Has been.

  The second dielectric substrate 2 includes a detection unit that detects the displacement of an object (not shown) based on the inductance (impedance) of the detection coil Co that changes according to the displacement of each of the detection bodies 30a and 30b. Each circuit which comprises (not shown) is provided. The detection unit includes an oscillation circuit that outputs an oscillation signal having a frequency corresponding to the inductance of the detection coil Co, and an oscillation period measurement circuit that outputs a signal corresponding to the period of the oscillation signal output from the oscillation circuit. The detection unit includes a square circuit that calculates and outputs the square value of the signal output from the oscillation period measurement circuit, a temperature compensation circuit that compensates for temperature fluctuations of the square value calculated by the square circuit, and a temperature compensation circuit. A signal processing circuit for detecting the displacement of each of the detection bodies 30a and 30b based on the output signal. Since these circuits are conventionally known as disclosed in Patent Document 1, detailed description thereof is omitted here.

  Here, the impedance of the detection coil Co actually includes a capacitance component and a resistance component due to winding resistance in addition to the inductance, but the inductance is dominant. Therefore, in the present embodiment, the displacement of the object can be detected substantially based on the impedance of the detection coil Co by detecting the displacement of the object based on the inductance of the detection coil Co as described above. .

  The holding body 31 of the rotor block 3 is formed in a bottomed cylindrical shape whose upper surface is opened by a synthetic resin material, and holds a pair of detection bodies 30a and 30b so as to protrude from the circumferential surface in the left-right direction by simultaneous molding. is doing. An intermediate body 32 that is formed in a cylindrical shape from a metal material and rotates integrally with the holding body 31 is fixed inside the holding portion 31 by an appropriate method such as press-fitting or simultaneous molding. The intermediate body 32 is fixed to a shaft body (not shown) interlocked with the object, and a fixing D-cut process is applied to the outer peripheral surface thereof. Here, a mark 32 a is engraved on the upper end surface of the intermediate body 32 along the radial direction. The positions of the detection bodies 30a and 30b on the circumferential track can be visually recognized from the outside of the cover 5 by the marks 32a and marks 50a formed on the upper surface of the main portion 50 to be described later.

  The body 4 is made of a synthetic resin molded product, and has a storage portion 40 formed in a flat bottomed cylindrical shape having an open top surface, and a rectangular cylindrical shape protruding rearward from the rear end side of the circumferential surface of the storage portion 40. And a connector housing portion 41. Further, a triangular flange portion 42 protruding forward is provided on the front end side of the circumferential surface of the storage portion 40. In addition, a magnetic shield body 43 formed into a flat bottomed cylindrical shape from a nonmagnetic material such as an aluminum plate is simultaneously formed in the storage section 40, and the magnetic shield body 43 is exposed inside the storage section 40. Yes.

  Two types of ribs 40a and 40b having different heights from the inner bottom surface project from the inner peripheral surface of the storage unit 40, and the ribs 40a and 40b are respectively provided on the upper surfaces of the two types of ribs 40a and 40b. Ribs 40c and 40d that are smaller than 40b project upward. The rib 40 c protruding from the upper surface of the rib 40 a having a low height is fitted into the narrow notch 12 of the first dielectric substrate 1. On the other hand, the rib 40 b having a high height is fitted into the wide notch 13 of the first dielectric substrate 1. Also, the rib 40 d protruding from the upper surface of the rib 40 b having a high height is fitted into the narrow notch 23 of the second dielectric substrate 2. Thus, the first dielectric substrate 1 is fixed to the upper surface of the rib 40a having a low height, and the second dielectric substrate 2 is fixed to the upper surface of the rib 40b having a high height.

  The connector housing part 41 is formed in a bottomed rectangular tube shape, and four contacts 46 are simultaneously formed on the inner bottom part thereof so as to be arranged at equal intervals along the left-right direction. Further, the front end portion (connecting portion with the storage portion 40) of the connector housing portion 41 has an open top surface, and the terminal piece 22 of the second dielectric substrate 2 is stored in the front end portion. Each contact 46 is formed by bending a rod-shaped metal material into a bowl shape, and an upper end portion thereof is inserted into each through hole 25 provided in the terminal piece 22 of the second dielectric substrate 2. Soldered to a land printed on the open end.

  The cover 5 is formed by integrally forming a disk-shaped main portion 50 and a rectangular plate-like terminal cover portion 51 protruding rearward from the rear end edge of the main portion 50 as a synthetic resin molded product. The cover 5 is attached to the upper surface of the body 4 so that the upper surface of the housing portion 40 of the body 4 is closed by the main portion 50 and the upper surface of the front end portion of the connector housing 41 is closed by the terminal cover portion 51. A magnetic shield body (not shown) formed in a ring shape from a nonmagnetic material such as an aluminum plate is simultaneously formed on the main portion 50, and the magnetic shield body is exposed on the lower surface side of the main portion 50. ing.

  The body 4 and the cover 5 are provided with thrust bearing portions 44 and 52 for receiving the thrust load of the rotor block 3 and radial bearing portions 45 and 53 for receiving the radial load of the rotor block 3, respectively.

  The thrust bearing portion 44 on the body 1 side is formed in a cylindrical shape that protrudes upward from the center of the bottom surface of the storage portion 40, and receives a thrust load by supporting the lower surface of the holding portion 31 of the rotor block 3 at its upper end surface. . Further, the radial bearing portion 45 on the body 1 side is composed of a peripheral portion of a circular through hole that opens in the center of the lower surface of the body 1, and supports the outer peripheral surface of the lower end portion of the intermediate body 32 inserted inside the thrust bearing portion 44. To receive a radial load.

  The thrust bearing portion 52 on the cover 5 side is formed in a cylindrical shape that protrudes downward from the center of the lower surface of the cover 5, and receives a thrust load by supporting the upper surface of the holding body 31 of the rotor block 3 at its lower end surface. Further, it is composed of a peripheral portion of a circular through hole that opens at the center of the upper surface of the cover 5, and receives a radial load by supporting the outer peripheral surface of the upper end portion of the intermediate body 32 that is inserted inside the thrust bearing portion 52.

  Thus, if the shaft body interlocking with the object is inserted into the intermediate body 32 and both are fixed, the intermediate body 32, that is, the rotor block 3 rotates integrally with the shaft body. 30b rotates on the circumference track.

  Hereinafter, the operation of the present embodiment will be briefly described. When the intermediate body 32 of the rotor block 3 interlocked with the object rotates in accordance with the displacement of the object, the detection bodies 30a and 30b are displaced from each other by 180 degrees in conjunction with the intermediate body 32 and displaced on the circumferential track. To do. As in the conventional example described in Patent Document 1, an oscillation signal having a frequency corresponding to the inductance of the detection coil Co that changes in accordance with the relative positions of the detection bodies 30a and 30b and the two sets of detection coils. Output from the oscillation circuit. By detecting the displacement of each detection body 30a, 30b based on this oscillation signal, the relative position information between each detection body 30a, 30b and the detection coil Co, that is, the amount of rotation of the object interlocked with the intermediate body 32 ( Rotation angle) can be detected. Since a specific detection method is conventionally known as disclosed in Patent Document 1, detailed description thereof is omitted here.

  Here, as shown in FIG. 1 (b), each detection coil of each dielectric substrate 1, 2 has a gap of a predetermined length along the displacement direction (circular orbit) of each detection body 30a, 30b. It consists of a plurality of first turns a0, b0 wound around g. Each detection coil of each dielectric substrate 1 and 2 further includes two second turns a1, a2, b1, and b2 that are folded back and wound so as to cross the gap g (in FIG. Only the dielectric substrate 1 is shown).

  If each detection coil of each of the dielectric substrates 1 and 2 is composed of only the first turns a0 and b0, the change in inductance of the detection coil Co with respect to the rotation angle of the object changes as shown by the broken line in FIG. Non-linear. In the figure, the inductance of the detection coil Co in a state where the rotation angle of the object is 0 ° (the detection bodies 30a and 30b and the detection coil Co do not overlap in the vertical direction) is 100%. On the other hand, when each detection coil of each of the dielectric substrates 1 and 2 has the second turns a1, a2, b1, and b2 as in the present embodiment, the folded portion of the second turns a1, a2, b1, and b2 As a result, the magnetic flux density of the detection coil Co changes. By utilizing the change in the magnetic flux density of the detection coil Co, the change in the inductance of the detection coil Co with respect to the rotation angle of the object can be made closer to a linearity compared to the broken line shown in FIG. 2 (solid line in FIG. 2). B).

  As described above, the detection coils of the dielectric substrates 1 and 2 of the present embodiment are folded back so as to cross the plurality of first turns a0 and b0 wound around the gap g and the gap g. And consists of second turns a1, a2, b1 and b2. For this reason, the inductance of the detection coil Co with respect to the displacement of the detection bodies 30a and 30b is changed by changing the magnetic flux density of the detection coil Co at the turn-back portion of the second turns a1, a2, b1, and b2 of the detection coils. Changes can be approximated linearly. Therefore, it is possible to improve the linearity of the change in inductance (impedance) of the detection coil Co even with respect to the displacement of the object interlocked with the displacement of each of the detection bodies 30a and 30b.

  In the present embodiment, the detection coils of the dielectric substrates 1 and 2 have a constant width dimension in the radial direction, and the radial direction when the second turns a1, a2, b1, and b2 are provided. There is no need to change the width dimension. For this reason, the inductance of the detection coil Co is not significantly reduced by increasing the radial width of each detection coil. Further, since it is not necessary to increase the width dimension in the radial direction of each detection coil, it is possible to avoid an increase in the size of the dielectric substrates 1 and 2.

  In the present embodiment, each of the detection bodies 30a and 30b is made of a nonmagnetic material, but may be made of a magnetic material having a high magnetic permeability. In this case, the change characteristic of the inductance with respect to the rotation angle of the target object is the reverse characteristic when each of the detection bodies 30a and 30b is formed of a nonmagnetic material. That is, the inductance of the detection coil Co increases as the rotation angle of the object increases. Even in this case, the linearity of the change characteristic of the inductance (impedance) with respect to the rotation angle of the object can be improved as described above.

  By the way, in this embodiment, although each dielectric substrate 1 and 2 is comprised by the 1 layer board | substrate, all may be comprised by a multilayer substrate (for example, 4 layer board | substrate). In this case, a pair of detection coils can be printed on each layer of each of the dielectric substrates 1 and 2. Here, a second turn is provided for each of the detection coils of each layer, and as shown in FIG. 3A, the second turns a1 to a7 and b1 to b7 of the detection coils of each layer are respectively connected to the dielectric substrates 1, respectively. It is preferable to dispose the two in the thickness direction so as not to overlap each other. By comprising in this way, the magnetic flux density of the detection coil Co can be changed in the folding | turning site | part of 2nd turn a1-a7, b1-b7. Thus, as shown in FIG. 3 (b), each detection is compared with the case where two second turns a1, a1, b1, b2 are provided in each detection coil of each dielectric substrate 1, 2. The change in the inductance (impedance) of the detection coil Co with respect to the displacement of the bodies 30a and 30b can be made closer to linear. In addition, it is not necessary to arrange the second turns of the detection coils so as not to overlap each other in the thickness direction in all the layers of the dielectric substrates 1 and 2, and the first of the detection coils of at least two layers. It's fine if the two turns do not overlap. For example, when each of the dielectric substrates 1 and 2 is formed of a four-layer substrate, the detection coils of the first to fourth layers of the first dielectric substrate 1 and the first to third layers of the second dielectric substrate 2 are used. Are assumed to overlap each other in the thickness direction. In this case, the above condition is satisfied unless only the second turn of each detection coil of the four layers of the second dielectric substrate 2 overlaps with the other second turn.

  By the way, in this embodiment, although the rotation-type position sensor which each detection body 30a, 30b displaces on a circumference track | orbit is demonstrated, it is a linear motion type position sensor which a detection body displaces on a linear track. There may be. Hereinafter, embodiments of the direct acting position sensor will be described with reference to the drawings. In this embodiment, as shown in FIG. 4A, a rectangular plate-shaped dielectric substrate A having a rectangular detection coil B printed on the upper surface and a non-magnetic material (for example, an aluminum plate) in a rectangular shape. And a formed detection body C. The detection body C is provided on a movable body D that holds the detection body C so as to be displaceable along the longitudinal direction of the dielectric substrate A. The movable body D is provided on the object so as to be displaced in conjunction with the object. Although not shown, the dielectric substrate A is provided with each circuit that constitutes a detection unit that detects the displacement of the object based on the inductance (impedance) of the detection coil B that changes according to the displacement of the detection body C. ing.

  The operation of this embodiment will be briefly described below. When the movable body D interlocked with the object is displaced along with the displacement of the object, the detection body C is displaced along the linear track in conjunction with the movable body D. Then, as in the embodiment of the rotational position sensor, an oscillation signal having a frequency corresponding to the inductance of the detection coil B that changes according to the relative position between the detection body C and the detection coil B is output from the oscillation circuit. By detecting the displacement of the detection body C based on this oscillation signal, it is possible to detect the relative position information between the detection body C and the detection coil B, that is, the amount of displacement of the object interlocked with the movable body D.

  Here, as shown in FIG. 4C, the detection coil B includes a plurality of first turns B0 wound around a gap g having a predetermined length along the longitudinal direction, and a gap It consists of second turns B1 to B8 which are folded back and wound across g. Thus, the change in inductance of the detection coil B with respect to the displacement of the detection body C can be made closer to linear compared to the case where the detection coil B consisting only of the first turn B0 shown in FIG. . Therefore, the linearity of the change in the inductance (impedance) of the detection coil B can be improved with respect to the displacement of the object interlocked with the displacement of the detection body C.

  In the above description, the dielectric substrate A is composed of a single-layer substrate, but the dielectric substrate A may be composed of a multilayer substrate, and the detection coil B may be provided in each layer. Further, a second turn may be provided for each layer of the detection coil B, and the second turns B1 to B8 of the detection coil of each layer may be arranged so as not to overlap each other in the thickness direction of the dielectric substrate A. . In this case, the same effect as described above can be obtained. Of course, it is not necessary to arrange the second turns of the detection coils so as not to overlap each other in the thickness direction in all the layers of the dielectric substrate A, and the second turns of the detection coils of at least two layers. It ’s good if they do n’t overlap. For example, when the dielectric substrate A is composed of a four-layer substrate, the second turns of the detection coils of the first to third layers of the dielectric substrate A are assumed to overlap each other in the thickness direction. In this case, the above condition is satisfied unless only the second turn of each detection coil of the four layers of the dielectric substrate A overlaps with the other second turn.

  By the way, in this embodiment, the displacement of the object is detected based on a change in the inductance of the detection coil. However, the displacement of the object is detected based on a change in another impedance parameter of the detection coil such as conductance. May be.

  In this embodiment, the position sensor includes a detection body. However, the detection body is provided separately from the position sensor when the detection body is the object itself or a part of the object. It may be done. Even in this case, the displacement of the object can be detected based on a change in inductance (impedance) of the detection coil.

  In this embodiment, the detection coil is formed by printing on a dielectric substrate. However, the detection coil may be formed by using other means such as etching, plating, or patterning using a laser. .

1 First dielectric substrate (substrate)
10a, 10b Detection coil 2 Second dielectric substrate (substrate)
30a, 30b Detector a0, b0 First turn a1, a2, b1, b2 Second turn g Gap

Claims (3)

  A detector coil that is disposed on the surface of a substrate made of a dielectric, and that changes in accordance with the displacement of the detector body, is disposed opposite to a detector body that displaces on a predetermined trajectory in conjunction with the displacement of the object. A detection unit that detects the displacement of the object based on the impedance of the detection coil, and the detection coil is wound so as to surround a gap having a predetermined length along the displacement direction of the detection body. A position sensor comprising a plurality of first turns and at least one second turn that is folded back and wound across the gap.   The substrate is formed of a multilayer substrate, and the detection coils are formed on the respective layers, and the second turns of the detection coils of at least two of the layers do not overlap each other in the thickness direction of the substrate. The position sensor according to claim 1, wherein the position sensor is disposed in a position. The position sensor according to claim 1, further comprising the detection body.

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