JP2015227826A - Position detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position detecting device capable of detecting biaxial movement (rotating movement and stroke movement) of a movable object with a simple structure.SOLUTION: A position detecting device 2 comprises a metal part 7 reciprocating in association with stroke movement of a movable object 1 (metallic rotor 5). A rotating position of the movable object 1 is determined by using outputs of a first specific range detection coil 4a to a third specific range detection coil 4c that vary in accordance with a rotating position of a metallic rotor 5 and based on the combination of the outputs. A stroke position of the movable object 1 is determined by the detection of an inductance change in accordance with a distance between an exciting coil 3 and the metal part 7.

Description

  The present invention relates to a position detection device that detects the position of a movable object.

  Conventionally, a position detection device (eddy current sensor) that calculates the position of a movable object by applying a magnetic field to a plurality of detection coils from an excitation coil and detecting a change in the magnetic field applied to the detection coil according to the rotation of the metal rotor. ) Is well known (see Patent Document 1). In this type of position detection device, the excitation coil and the detection coil are electromagnetically coupled, and the induced electromotive force appearing in the detection coil changes according to the rotation position of the metal rotor, so that the movement of the movable object is detected from the change in the induced electromotive force. A moving position is detected.

JP 2002-365006 A

  By the way, some movable objects take, for example, two-axis operations of rotation and stroke movement, and there is a need to detect these movements. In response to this need, it has been desired to develop a technique capable of detecting the biaxial motion of a movable object with a simple configuration.

  An object of the present invention is to provide a position detection device capable of detecting a biaxial operation (rotation and stroke movement) of a movable object with a simple configuration.

  A position detection device that solves the above-described problem includes an excitation coil that generates a magnetic field, one or more specific range detection coils that can detect a magnetic field generated from the excitation coil, and a synchronous rotation with a movable object. In a configuration including a metal rotor that changes the magnetic field applied to the specific range detection coil according to the rotational position of the movable object, the magnetic coil approaches and moves away from the excitation coil according to the stroke movement of the movable object. And the excitation position of the exciting coil that changes in accordance with the distance from the metal part while calculating the rotational position of the movable object based on the specific range signal output from the specific range detection coil A position calculation unit that calculates a stroke position of the movable object by detecting a change directly or indirectly.

  According to this configuration, when the movable object rotates, a magnetic field corresponding to the shape of the facing metal rotor is generated in the specific range detection coil, so the rotation position of the movable object is based on the output of the specific range detection coil. Can be detected. Further, when the movable object moves in a stroke, the inductance of the exciting coil changes as the metal part approaches or moves away from the exciting coil according to the operation, so the stroke position of the movable object is detected based on this inductance change. It becomes possible. In this way, when detecting the biaxial movement of the movable object such as the rotation and the stroke movement, no additional component is required on the substrate of the position detection device. Therefore, it is possible to detect the biaxial movement of the movable object with a simple configuration.

  In the position detection device, it is preferable that the metal portion is disposed on the same axis as the metal rotor, and is configured to rotate about the same axis as the movable object that rotates. According to this configuration, it is possible to make the metal part a simple one that moves in the same manner as the movable object, which is further advantageous in simplifying the device configuration.

  The position detection device preferably includes a detection circuit that directly detects an inductance of the exciting coil, and the position calculation unit calculates a stroke position of the movable object based on an output of the detection circuit. According to this configuration, since the inductance change of the exciting coil is directly detected, it is advantageous for more accurately determining the stroke movement of the movable object.

  In the position detection device, the position calculation unit detects a change in mutual inductance between the excitation coil and the specific range detection coil based on the specific range signal from the specific range detection coil, and based on the change. It is preferable to calculate the stroke position of the movable object. According to this configuration, since the inductance change of the exciting coil is indirectly detected, a dedicated detection circuit for detecting the inductance change becomes unnecessary. Therefore, it becomes further advantageous for simplification of the apparatus.

  In the position detection device, the position calculation unit calculates the rotation position using an output of a linear area in the plurality of specific range signals, and the position calculation unit detects the rotation position. It is preferable to calculate the stroke position of the movable object using the outputs of the plurality of specific range detection coils to be used. According to this configuration, it is possible to detect both rotation and stroke movement of the movable object using a common specific range signal.

  In the position detection device, the position calculation unit calculates the rotation position using an output of a linear area in the plurality of specific range signals, and the position calculation unit detects the rotation position. It is preferable to calculate the stroke position of the movable object based on the output of the specific range detection coil that is not used. According to this configuration, it is possible to detect the stroke movement of the movable object by effectively using the specific range signal that is not used for the rotation detection.

  According to the present invention, it is possible to detect a biaxial operation (rotation and stroke movement) of a movable object with a simple configuration.

The block diagram of the position detection apparatus of 1st Embodiment. The perspective view of the position detection apparatus with which the metal part was pushed in back in the stroke direction. The perspective view of the position detection apparatus from which the metal part was pulled out in the stroke direction. (A), (b) is a conceptual diagram which shows the structural example of the stroke movement of a metal part. The electrical block diagram of a position detection apparatus. The wave form diagram of the specific range signal in 0 ° ≦ 0 <72 °. (A) is a conceptual diagram which shows the metal part before stroke operation, (b) is a conceptual diagram which shows the metal part by which stroke operation was carried out. The graph which shows the relationship between a rotor rotation angle and mutual inductance in 2nd Embodiment. The change figure of the specific range signal with respect to stroke movement. The change figure of the specific range signal with respect to stroke movement.

(First embodiment)
Hereinafter, a first embodiment of a position detection device will be described with reference to FIGS.
As shown in FIGS. 1 to 3, for example, a vehicle-mounted device such as a switch device includes a position detection device 2 that can detect the position of a movable object 1 that is provided to move in the vehicle-mounted device. The position detection device 2 can detect the rotation position and the stroke position of the movable object 1 capable of both rotation and stroke movement, for example. The movable object 1 is, for example, a switch or a lever.

  The position detecting device 2 includes an exciting coil 3 that generates a magnetic field (magnetic flux) through current, one or more specific range detecting coils 4 that can detect a magnetic field generated from the exciting coil 3, and a metal that rotates in synchronization with the movable object 1. And a rotor 5. The excitation coil 3 and the specific range detection coil 4 are provided on the side that supports the movable object 1. When a current flows through the excitation coil 3, an induced electromotive force is generated in the specific range detection coil 4 by electromagnetic induction. The metal rotor 5 is provided so as to rotate together with the movable object 1. The metal rotor 5 changes the magnetic field applied to the specific range detection coil 4 according to the position of the movable object 1.

  The metal rotor 5 rotates around the rotation center P in conjunction with the movable object 1. The metal rotor 5 includes a plurality of rotor pieces 5a extending in the rotor radial direction, an inner peripheral connecting portion 5b that connects the rotor pieces 5a on the inner side in the rotor radial direction, and an outer peripheral connection that connects the rotor pieces 5a on the outer side in the rotor radial direction. It is formed in the shape provided with the part 5c. The plurality of rotor pieces 5a are arranged at equal intervals in the rotor rotation direction (the direction of arrow A in FIG. 1). The metal rotor 5 rotates on the same axis as the movable object 1.

  The metal rotor 5 includes one rotor piece 5a, an inner peripheral connection portion 5b and an outer peripheral connection portion 5c connected to the rotor piece 5a, and one rotor piece 5a located next to a component group of these 5a to 5c. And a plurality of sets. When the plane in the rotation direction of the metal rotor 5 is the rotor rotation direction plane (XY axis plane in FIG. 1), one set of set angles R1 in the metal rotor 5 is set to “72 °”, for example. Yes.

  Three specific range detection coils 4 are provided, 4a to 4c. These first specific range detection coil 4a to third specific range detection coil 4c are arranged side by side around the rotation center P of the movable object 1, that is, along the rotor rotation direction (the direction of arrow A in FIG. 1). The first specific range detection coil 4a to the third specific range detection coil 4c are formed around the entire circumference around the rotation center P. When the metal rotor 5 rotates, the shape of the metal rotor 5 to be covered changes, and the detection voltage of the first specific range detection coil 4a to the third specific range detection coil 4c changes in an alternating wave shape (sine wave shape or triangular wave shape). .

  The excitation coil 3 and the first specific range detection coil 4a to the third specific range detection coil 4c are arranged so as to overlap each other by a predetermined amount in the axial direction of the metal rotor 5 (the depth direction in FIG. 1). In this case, if the exciting coil 3 and the first specific range detection coil 4a to the third specific range detection coil 4c are formed on the substrate 6 of the position detection device 2 (see FIGS. 2 and 3), They are arranged in an overlapping manner by an arrangement pattern in which electrical insulation is secured through through holes (not shown). The phase shift between the first specific range detection coil 4a and the second specific range detection coil 4b is, for example, “24 °”. The phase shift between the first specific range detection coil 4a and the third specific range detection coil 4c is, for example, “24 °”.

  The set angle of each of the first specific range detection coil 4 a to the third specific range detection coil 4 c (hereinafter referred to as loop angle R <b> 2) is “72 °” in accordance with one unit of the set of metal rotors 5. Thereby, in the specific range detection coil 4 per one, it is possible to detect the angle of 0 degree-72 degrees.

  The exciting coil 3 is formed in a shape that can cover the entire area of the specific range detecting coil 4. In the case of this example, the exciting coil 3 connects the outer peripheral winding portion 3a wound around the outer side in the rotor radial direction and the inner peripheral winding portion 3b wound around the inner side in the rotor radial direction. And a connecting portion 3c. The excitation coil 3 is provided on the same substrate as the specific range detection coil 4.

  The position detection device 2 includes a metal portion 7 that can approach and separate from the excitation coil 3 according to the stroke movement of the movable object 1. The metal part 7 is formed in a disk shape. The metal part 7 is rotated and stroked in synchronization with the movable object 1 by being attached to the movable object 1, for example. The metal part 7 is arranged on a concentric axis with respect to the metal rotor 5. When the movable object 1 moves in a stroke, the distance W in the stroke direction (the direction of arrow B in FIGS. 2 and 3) between the exciting coil 3 (substrate 6) and the metal part 7 changes.

  FIGS. 4A and 4B illustrate a method for arranging the metal portion 7. The metal part 7 is good also as a shape pivotally supported by the outer periphery of the rotating shaft 8 connected and fixed to the movable body 1 as shown to Fig.4 (a). Moreover, the metal part 7 is good also as a shape accommodated in the inside of the cylindrical rotating shaft 9 so that linear reciprocation is possible as shown in FIG.4 (b).

  As shown in FIG. 5, the position detection device 2 includes a position calculation unit 10 that calculates the rotation position and stroke position of the movable object 1. An excitation coil 3 is connected to the position calculation unit 10 via an excitation circuit 11. A resistor 12 for detecting a current flowing in the circuit is connected to the high potential side of the exciting coil 3. The resistor 12 may be either the internal resistance or the external resistance of the exciting coil 3. The first specific range detection coil 4a to the third specific range detection coil 4c that are electromagnetically coupled to the excitation coil 3 are connected to the position calculation unit 10 via detection circuits 13a, 13b, and 13c, respectively. The detection circuits 13a to 13c are circuits that perform, for example, signal amplification and modulation.

  The position calculating unit 10 generates a magnetic field (magnetic flux) from the exciting coil 3 by applying an AC voltage to the exciting coil 3, and the first specific range detecting coil 4a to the third specific range detecting coil 4c by mutual induction action. To generate an induced electromotive force. At this time, the position calculation unit 10 receives the first specific range signal S1-a from the first specific range detection coil 4a through the detection circuit 13a, and the second specific range signal from the second specific range detection coil 4b through the detection circuit 13b. S1-b is input, and the third specific range signal S1-c is input from the third specific range detection coil 4c through the detection circuit 13c.

  A detection circuit 14 that directly detects the inductance of the exciting coil 3 is connected to the resistor 12. The detection circuit 14 outputs an excitation coil detection signal S2 to the position calculation unit 10 as a signal corresponding to the detected inductance of the excitation coil 3.

  The position calculation unit 10 determines the rotation position of the movable object 1, that is, the rotation of the metal rotor 5, based on the combination of the first specific range signal S1-a, the second specific range signal S1-b, and the third specific range signal S1-c. The angle (rotor angle θ) is calculated. In addition, the position calculation unit 10 calculates the stroke position of the movable object 1 based on the excitation coil detection signal S2.

Next, the operation of the position detection device 2 will be described with reference to FIGS. 6 and 7.
As shown in FIG. 6, the position of the position detection device 2 at the left end in FIG. 6 is set to a reference “0 °”, and the metal rotor 5 is rotated from this reference position in the direction of arrow A1 in the figure. . When an alternating voltage is applied to the exciting coil 3, an induced electromotive force is generated in the first specific range detection coil 4a to the third specific range detection coil 4c by a mutual induction action. In this state, when the metal rotor 5 starts to rotate around the rotation center P, the detection voltages of the first specific range detection coil 4a to the third specific range detection coil 4c according to the shape of the metal rotor 5 facing each other. (Amplitude) changes in an alternating wave shape (an example is a sine wave shape or a triangular wave shape). That is, when the first specific range signal S1-a is used as a reference, the second specific range signal S1-b whose phase is “24 °” late is output, and the third specific range signal S1-c whose phase is “24 °” early is output. Is output.

  The position calculation unit 10 has a signal waveform in a linear region among the first specific range signal S1-a, the second specific range signal S1-b, and the third specific range signal S1-c (exists in the region U). The detection angle θk that can be calculated from the output of the specific range detection coil 4, that is, the rotor angle θ in the range of 0 ° to 72 ° is calculated. For example, when the rotor angle θ is in the range of about 12 ° to 24 °, S1-b and S1-c are used, and when the rotor angle θ is about 24 ° to 36 °, S1-a and S1-c are used. When the rotor angle θ is about 36 ° to 48 °, S1-a and S1-b are used. In this way, the position calculation unit 10 calculates the rotor angle θ within a range of 72 ° per cycle.

  As shown in FIG. 7A, when the movable object 1 is located at the initial position before the stroke operation, the metal part 7 is located at a far place away from the exciting coil 3 by the distance “Wa”. Thereby, an inductance La corresponding to the distance Wa is generated in the exciting coil 3, and a voltage corresponding to the inductance La is generated in the resistor 12 (current flows). Therefore, the excitation circuit detection signal S2-a corresponding to the inductance La is output from the detection circuit 14 to the position calculation unit 10. The position calculator 10 determines that the movable object 1 (metal part 7) is located at the initial position by receiving the excitation coil detection signal S2-a from the detection circuit 14.

  As shown in FIG. 7B, when the movable object 1 is stroked from the initial position to the back (push operation), the excitation coil 3 has a stroke amount of the metal part 7, that is, the excitation coil 3 and the metal part 7. An inductance Lb (<La) corresponding to the distance Wb is generated, and a voltage corresponding to the inductance Lb is generated in the resistor 12 (current flows). Therefore, the excitation circuit detection signal S2-b corresponding to the inductance Lb is output from the detection circuit 14 to the position calculation unit 10. The position calculation unit 10 calculates the stroke amount of the movable object 1 (metal part 7) based on the excitation coil detection signal S2-b input from the detection circuit 14.

  When the movable object 1 is operated to the maximum stroke position, an inductance Lmax corresponding to the maximum stroke amount is generated in the exciting coil 3. Therefore, the position calculator 10 determines that the movable object 1 is located at the maximum stroke position by inputting the excitation coil detection signal S2-c according to the inductance Lmax from the detection circuit 14. In this way, the position calculation unit 10 detects the stroke position of the movable object 1 (metal part 7) between the initial position and the maximum stroke position.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) The position detection device 2 includes a metal portion 7 that reciprocates in conjunction with the movable object 1 (metal rotor 5) moving in a stroke. When the movable object 1 rotates, the first specific range detection coil 4a to the third specific range detection coil 4c generate a magnetic field according to the shape of the metal rotor 5 facing the first specific range detection coil 4a. It is possible to detect the rotational position of the movable object 1 based on the combination of the outputs of the third specific range detection coil 4c. Further, when the movable object 1 is moved in a stroke, the inductance L of the exciting coil 3 changes as the metal part 7 approaches or separates from the exciting coil 3 according to the operation thereof. 1 stroke position can be detected. As described above, when detecting the biaxial movement of the movable object 1 such as the rotation and the stroke movement, it is not necessary to add components to the 6 tatami mat of the position detection device 2. Therefore, the biaxial movement of the movable object 1 can be detected with a simple configuration.

  (2) The metal portion 7 is arranged on the same axis as the metal rotor 5 and is formed to rotate about the same axis as the rotating movable object 1 (around the rotation center P). Therefore, it is possible to make the metal part 7 simple that takes the same movement as the movable object 1, which is more advantageous for simplification of the apparatus.

  (3) A detection circuit 14 for detecting a voltage change (current change) of the excitation coil 3 is provided, and based on the output of the detection circuit 14, an inductance change of the excitation coil 3 is directly detected to determine the stroke position of the movable object 1. judge. Therefore, since the value of the inductance change of the exciting coil 3 is directly monitored, it is advantageous for more correctly determining the stroke movement of the movable object 1.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. In addition, 2nd Embodiment is an Example which changed the detection method of the stroke position as described in 1st Embodiment. Therefore, the same part as 1st Embodiment attaches | subjects the same code | symbol, description is abbreviate | omitted, and only a different part is demonstrated.

  As shown in FIG. 8, when the inductance L of the excitation coil 3 changes due to the switching of the distance W between the excitation coil 3 and the metal part 7, the mutual inductance M between the excitation coil 3 and the specific range detection coil 4 also changes. . As a result, the induced electromotive force of the specific range detection coil 4 changes. If this change is detected, the inductance change of the excitation coil 3 should be detected indirectly. In this example, the stroke amount of the movable object 1 is detected using this principle.

[Detection method 1]
FIG. 9 illustrates a detection example using the outputs of the two specific range detection coils 4 used for detecting the rotation of the movable object 1. Here, an example in which the outputs of the two specific range detection coils 4 are summed and an example in which the sum is divided by the difference are given. As can be seen from the figure, when the distance W between the excitation coil 3 and the metal part 7 changes, the sum or difference / sum of the detection voltages of the two specific range detection coils 4 changes (smaller when the distance W is shorter, Therefore, the stroke position of the metal portion 7 can be detected by detecting this change.

  Specifically, since the rotation position of the movable object 1 is calculated from the difference between the two specific range detection coils 4, the value of the sum or the difference / sum is determined based on the rotation position specified by the calculation. The stroke position is detected by confirming whether or not to take. For example, when the rotor angle θ is determined to be “about 6 °”, if the sum is “V1”, it is determined that the metal portion 7 is at a far position in the stroke direction, and the sum is “V2”. If it has taken, it will determine with the metal part 7 being in the position close | similar in a stroke direction. In the case of this example, the metal portion 7 is supposed to move by stroke, but as can be seen from the figure, there is no change in the sum or difference / sum, so that the rotation detection is not affected.

[Detection method 2]
FIG. 10 illustrates a detection example using the output of one specific range detection coil 4 that is not used for detecting the rotation of the movable object 1. In the case of this example, the stroke amount of the metal part 7 is detected using the output of the region U ′ shown in FIG. As can be seen from the figure, the output of the specific range detection coil 4 not used for detecting the rotation of the movable object 1 (area U ′ in the figure) depends on the distance W between the excitation coil 3 and the metal part 7. Since it changes, the stroke position of the metal part 7 can be detected by detecting this change.

  Specifically, since the rotation position is specified by calculation from the outputs of the two specific range detection coils 4 used for rotation detection, one specific range detection not used for rotation detection is based on the rotation position. The stroke position is detected by checking which value the output of the coil 4 takes. For example, when the rotor angle θ is determined to be “about 18 °”, if the output of one specific range detection coil 4 not used for rotation detection is “Va”, the metal portion 7 is in the stroke direction. If it determines with it being in a far position and the output has taken "Vb", it will determine with the metal part 7 being in the near position in a stroke direction.

According to the configuration of the present embodiment, the following effects can be obtained.
(4) When the metal part 7 approaches or separates, the inductance of the excitation coil 3 changes, and the mutual inductance of the excitation coil 3 and the specific range detection coil 4 changes. This change in mutual inductance is detected, and the stroke position of the movable object 1 is determined based on this change. Thus, in this example, since the inductance change of the exciting coil 3 is indirectly detected, a dedicated circuit (the detection circuit 14 of the first embodiment) for detecting this is not necessary. Therefore, it becomes further advantageous for simplification of the apparatus.

(5) If the detection method 1 is adopted, both the rotation and the stroke movement of the movable object 1 can be detected using the specific range signal S1 used for the rotation detection of the movable object 1.
(6) If the detection method 2 is employed, the stroke movement of the movable object 1 can be detected by effectively using the specific range signal S1 that is not used for rotation detection.

Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.
The metal part 7 is not limited to the disk shape, and can be changed to other shapes such as a rectangular parallelepiped shape.

-The metal part 7 does not need to be arrange | positioned so that a metal rotor 5 and an axis | shaft may correspond.
The first specific range detection coil 4 a to the third specific range detection coil 4 c are not limited to being formed over the entire circumference of the substrate 6, but may be formed only partially.

The excitation coil 3 and the specific range detection coil 4 may have a shape in which the coil patterns do not overlap at all in the thickness direction of the substrate.
The phase shift amount of the first specific range detection coil 4a to the third specific range detection coil 4c is not limited to “24 °”, and may be changed to another value.

The number of the specific range detection coils 4 is not limited to three and may be changed to other numbers.
The excitation coil 3 may take a shape pattern that covers only a part of the specific range detection coil 4. Moreover, the shape pattern which is not covered at all may be sufficient.

The excitation coil 3 can be changed to various shapes as long as a desired output can be obtained from the specific range detection coil 4.
The shape of the metal rotor 5 can be changed to various shapes as long as a desired output can be obtained from the specific range detection coil 4.

The determination of the stroke position may be, for example, a determination of two positions whether or not the push is pushed.
The position detection device 2 may detect the movable object 1 that moves linearly.

  The position detection device 2 can be applied to various devices and apparatuses.

  DESCRIPTION OF SYMBOLS 1 ... Movable object, 2 ... Position detection apparatus, 3 ... Excitation coil, 4 (4a-4c) ... Specific range detection coil, 5 ... Metal rotor, 7 ... Metal part, 10 ... Position calculating part, 14 ... Detection circuit, S1 ... specific range signal, S1-a ... first specific range signal, S1-b ... second specific range signal, S1-c ... third specific range signal, W (Wa, Wb) ... distance, L (La, Lb, Lmax) ... inductance, M ... mutual inductance, P ... center of rotation, U ... region where the output is linear.

Claims (6)

An excitation coil that generates a magnetic field, one or more specific range detection coils that can detect the magnetic field generated from the excitation coil, and a magnetic field applied to the specific range detection coil by rotating in synchronization with a movable object In the position detection device provided with a metal rotor that changes according to the rotational position of the movable object,
A metal part capable of approaching and separating from the exciting coil in accordance with a stroke movement of the movable object;
Based on the specific range signal output from the specific range detection coil, the rotational position of the movable object is calculated, and the inductance change of the exciting coil that changes according to the distance from the metal part is detected directly or indirectly. And a position calculating unit that calculates a stroke position of the movable object. 2. The position detection according to claim 1, wherein the metal portion is disposed on the same axis as the metal rotor, and is configured to rotate about the same axis as the movable object that rotates. apparatus. A detection circuit for directly detecting the inductance of the exciting coil;
The position detection device according to claim 1, wherein the position calculation unit calculates a stroke position of the movable object based on an output of the detection circuit. The position calculation unit detects a change in mutual inductance between the excitation coil and the specific range detection coil based on the specific range signal from the specific range detection coil, and based on this change, the stroke position of the movable object The position detection device according to claim 1, wherein The position calculation unit calculates the rotation position using an output of a linear area in the plurality of specific range signals,
5. The position detection device according to claim 4, wherein the position calculation unit calculates a stroke position of the movable object using outputs of the plurality of specific range detection coils used for detection of a rotation position. . The position calculation unit calculates the rotation position using an output of a linear area in the plurality of specific range signals,
The position detection device according to claim 4, wherein the position calculation unit calculates a stroke position of the movable object based on an output of a specific range detection coil that is not used for detecting a rotation position.