JP2015094720A - Position sensing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position sensing device capable of detecting a position of a mobile object over a wide detection range.SOLUTION: A position sensing device 2 includes an excitation coil 3 and specific range angle sensing coils 4a-4c capable of sensing an angle of a metallic rotor 5 in every 72° cycle. The position sensing device 2 also includes a first absolute angle sensing coil 11 comprising one or more sets of a plurality of windings 12 arranged in a rotational direction of the metallic rotor 5, and a second absolute angle sensing coil 13 which outputs a detection signal out of phase with output of the first absolute angle detection coil 11. Different combinations of outputs from the two absolute angle sensing coils 11, 13 are used for every 72°, or an angle detection cycle of the specific range angle sensing coils 4. The position sensing device 2 computes the angle of the metallic rotor 5 on the basis of output from the specific range angle sensing coils 4 and output from the absolute angle sensing coils 11, 13.

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

  However, the position detection device of Patent Document 1 has a problem that only a certain range of angles can be determined when detecting the rotation angle of the movable object. Therefore, there has been a need for technology development that can detect the rotational position of the movable object over a wide range. Note that the position to be detected is not limited to the rotation position described above, and includes various positions such as a position in a linear direction.

  An object of the present invention is to provide a position detection device capable of widening a detection range when detecting the position of a movable object.

  A position detection device that solves the above problems includes an exciting coil through which an electric current flows, one or more specific range angle detecting coils that can detect a magnetic field generated from the exciting coil, and the position of a movable object that is a position detection target. And a metal body that changes a magnetic field applied to the specific range angle detection coil in accordance with the first range, and includes a plurality of winding portions arranged in the moving direction of the movable object. A first absolute angle detection coil; a second absolute angle detection coil that outputs a detection signal having a phase different from that of the first absolute angle detection coil; a first absolute angle signal output from the first absolute angle detection coil; The combinations constructed from the second absolute angle signals output from the two absolute angle detection coils are different for each position detection cycle based on the specific range angle signals of the AC waves output from the specific range angle detection coils. The magnetic field change applying unit formed on the metal body to change the magnetic field applied to the first absolute angle detecting coil and the second absolute angle detecting coil, the specific range angle signal, And a position calculator that calculates the position of the movable object by a combination of an absolute angle signal and a second absolute angle signal.

  According to this configuration, the position of the movable object is determined by the combination of the output of the specific range angle detection coil, the output of the first absolute angle detection coil, and the output of the second absolute detection coil. Compared with the case where the position is detected only by the output of the coil, the position of the movable object can be detected in a wider range. Therefore, it is possible to widen the detection range when detecting the position of the movable object.

  In the position detection device, the metal body is a metal rotor that is interlocked with the rotating movable object, and the plurality of winding portions in the same set are arranged side by side in the rotation direction of the metal rotor, and the position It is preferable that the calculation unit calculates the rotational position of the movable object. According to this configuration, the rotational position of the metal rotor can be detected in a wide range.

  In the position detection device, it is preferable that a plurality of sets of the winding portions are arranged in the radial direction of the metal rotor. According to this configuration, an optimum signal corresponding to the position of the movable object can be easily output from the first absolute angle detection coil, which is advantageous for ensuring the accuracy of position detection.

  In the position detection device, the magnetic field change applying unit changes a magnetic field applied to the first absolute angle detecting coil and a first magnetic field change applying unit that changes the magnetic field applied to the first absolute angle detecting coil. It is preferable to provide the 2nd magnetic field change provision part to be made. According to this configuration, since the magnetic field change imparting unit is provided in each of the first absolute angle detection coil and the second absolute angle detection coil, a change suitable for each of the first absolute angle detection coil and the second absolute angle detection coil. It becomes easy to apply a magnetic field.

  In the position detection device, the first magnetic field change applying unit includes a metal part of a metal rotor and a plurality of recesses arranged in a rotation direction of the metal rotor, and the plurality of recesses are the metal rotor. It is preferable that the concavity is recessed so that the size sequentially changes in the rotation direction. According to this configuration, when the first magnetic field change applying unit is provided, it can be realized with a simple structure in which the metal part is provided with the metal part and the concave part.

  In the position detection device, a pair of the winding portions are provided in the same set, and a plurality of sets are provided so that the sets are arranged in the radial direction of the metal rotor, and the winding is formed by arranging a plurality of pairs. The portions are arranged so that the protrusions formed on the metal rotor are arranged on one side along one side wall of the protrusion, and the ones arranged on the other side are arranged on the other side wall of the protrusion. It is preferable to arrange | position so that it may follow. According to this configuration, which winding is covered with the metal portion and which winding is covered with the concave portion is advantageous for accurately switching.

  In the position detection device, it is preferable that the winding portion is formed so that a coil diameter sequentially increases toward a radially outer side of the metal rotor. According to this configuration, it is more advantageous to switch accurately which winding is covered with the metal part and which winding is covered with the recess.

  In the position detection device, it is preferable that the first absolute angle detection coil and the second absolute angle detection coil are disposed inside the excitation coil and the specific range angle detection coil in a radial direction of the metal rotor. According to this configuration, the absolute angle detection coil can be made with a small diameter.

  In the position detection device, it is preferable that the position calculation unit selects two signals having a linear signal waveform from among the plurality of specific range angle signals, and calculates the position of the movable object from these signals. According to this configuration, it is possible to detect the position with a component that linearly changes in the specific range angle signal, which is advantageous for accurately determining the position of the movable object.

  According to the present invention, it is possible to widen the detection range when detecting the position of the movable object.

The schematic block diagram of the position detection apparatus of one Embodiment. The top view which shows the shape of a metal rotor. Explanatory drawing which shows the shape pattern of an absolute angle detection coil. The electrical block diagram of a position detection apparatus. The wave form diagram which shows the relationship between a rotor angle and the output voltage of a specific range angle detection coil. The waveform change figure of each coil output and detection angle at the time of 0 degrees <= theta <72 degrees. The waveform change figure of each coil output and detection angle when 72 ° ≦ θ ≦ 144 °. The waveform change figure of each coil output and detection angle at the time of 288 degrees <= theta <= 360 degrees. The output change figure of each absolute angle detection coil between 0 degrees <= theta <360 degrees.

Hereinafter, an embodiment of the position detection device will be described with reference to FIGS.
As shown in FIG. 1, 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 moves in the vehicle-mounted device. The position detection device 2 is preferably a device that detects the rotation position of the movable object 1 that rotates, for example. The movable object 1 is preferably a switch or a lever, for example.

  The position detection device 2 includes an excitation coil 3 to which a current is applied, one or more specific range angle detection coils 4 that can detect a magnetic field generated from the excitation coil 3, and the position of the movable object 1 that is a position detection target. And a metal body (hereinafter referred to as a metal rotor 5) that changes the magnetic field applied to the specific range angle detection coil 4. The excitation coil 3 and the specific range angle detection coil 4 are preferably provided on the side on which the movable object 1 is fixed. The metal rotor 5 is preferably provided on the movable object 1.

  The metal rotor 5 is preferably rotated around the rotation center P in conjunction with the movable object 1. It is preferable that a plurality of projecting pieces 7 projecting from the rotor body 6 to the radially outer side of the metal rotor 5 are formed on the outer periphery of the metal rotor 5. The plurality of projecting pieces 7 are preferably arranged at equal intervals in the rotation direction of the metal rotor 5 (the direction of arrow A in FIG. 1). On the outer periphery of the metal rotor 5, a recess 8 is formed between the adjacent projecting pieces 7. Therefore, on the outer periphery of the metal rotor 5, the projecting pieces 7 and the recesses 8 are alternately arranged at equal intervals along the rotation direction of the metal rotor 5. The projecting piece 7 is preferably formed in a substantially fan shape, for example. The metal rotor 5 is preferably rotated on the same axis as the movable object 1.

  When the plane in the rotation direction of the metal rotor 5 is the rotor rotation direction plane (XY plane in FIG. 1), the set angle R1 in the rotor rotation direction plane of the projecting piece 7 and the rotor rotation of the recess 8 The set angle R2 in the direction plane is preferably the same angle. The set angles R1 and R2 are a line La extending from the rotation center P of the metal rotor 5 to one side wall 9 of the projecting piece 7, and the other side wall 10 of the projecting piece 7 from the rotation center P of the metal rotor 5. This corresponds to the angle formed by the line Lb extending to. The setting angles R1 and R2 are preferably “36 °”, for example.

  It is preferable that three specific range angle detection coils 4 are provided, for example, 4a to 4c. In the case of this example, it is assumed that the second specific range angle detection coil 4b and the third specific range angle detection coil 4c are arranged on both sides of the first specific range angle detection coil 4a. The set angle of the specific range angle detection coil 4 (hereinafter referred to as the loop angle Rk) is preferably “72 °” in accordance with the angular range of the pair of protrusions 7 and recesses 8, for example. In other words, the specific range angle detection coil 4 per one can detect an angle of 0 ° to 72 °.

  The specific range angle detection coils 4a to 4c are preferably arranged side by side in the rotational direction of the metal rotor 5 and are arranged by a predetermined amount in the axial direction of the metal rotor 5 (Z-axis direction in FIG. 1). . The specific range angle detection coils 4a to 4c are preferably formed on, for example, a substrate (not shown) of the in-vehicle device (position detection device 2). (Not shown) may be used to ensure mutual electrical insulation. The phase shift between the first specific range angle detection coil 4a and the second specific range angle detection coil 4b is preferably, for example, “24 °”. The phase shift between the first specific range angle detection coil 4a and the third specific range angle detection coil 4c is preferably, for example, “24 °”.

  The excitation coil 3 is preferably formed so as to cover all of the plurality of specific range angle detection coils 4a to 4c, for example. The exciting coil 3 is preferably bent in an arc shape in accordance with the arrangement pattern of the specific range angle detection coils 4 a to 4 c arranged in an arc shape along the rotation direction of the metal rotor 5. The excitation coil 3 may be formed on the same substrate as the specific range angle detection coils 4a to 4c.

  The position detection device 2 includes a first absolute angle detection coil 11 including one or more sets of a plurality of winding portions 12 arranged in the moving direction of the movable object 1 and a phase different from that of the first absolute angle detection coil 11. And a second absolute angle detection coil 13 for outputting a detection signal. The position detection device 2 has a combination constructed from the first absolute angle signal Sa output from the first absolute angle detection coil 11 and the second absolute angle signal Sb output from the second absolute angle detection coil 13. The first absolute angle detection coil 11 and the second absolute angle detection coil 13 have different combinations for each position detection cycle based on the specific range angle signal S1 of the AC wave output from the specific range angle detection coil 4. A magnetic field change applying unit 14 formed on a metal body (metal rotor 5) is provided to change the applied magnetic field.

  The plurality of winding portions 12 in the same set are preferably arranged side by side in the rotation direction of the metal rotor 5 (the direction of arrow A in FIG. 1), for example. It is preferable that a plurality of sets of winding portions 12 are arranged side by side in the radial direction of the metal rotor 5. In the case of this example, for example, a pair of winding portions 12 are provided in the same set, and four sets are provided. That is, four sets each including two winding portions 12 are provided, and a total of eight winding portions 12 are provided. In this example, the group farthest from the rotation center P is 12a, 12b, the next farthest group is 12c, 12d, the next farthest group is 12e, 12f, and the group closest to the rotation center P is 12g. , 12h.

  The winding portions 12 a, 12 c, 12 e, and 12 g arranged on one side (the left side in the drawing) of the plurality of winding portions 12 are preferably arranged side by side along the radial direction of the metal rotor 5. In addition, the winding portions 12 b, 12 d, 12 f and 12 h arranged on the other side (the right side in the drawing) of the plurality of winding portions 12 are also preferably arranged side by side along the radial direction of the metal rotor 5.

  The magnetic field change applying unit 14 includes a first magnetic field change applying unit 14a that changes the magnetic field applied to the first absolute angle detection coil 11, and a second magnetic field change that changes the magnetic field applied to the second absolute angle detection coil 13. It is preferable to provide the provision part 14b. The second absolute angle detection coil 13 and the second magnetic field change applying unit 14b are required to have an angle in a range that cannot be detected by the first absolute angle detection coil 11 and the first magnetic field change applying unit 14a. This is because the angle in this range is determined by the second absolute angle detection coil 13 and the second magnetic field change applying unit 14b.

  The first magnetic field change applying unit 14 a preferably includes the metal part 15 of the metal rotor 5 and the above-described plurality of recesses 8 arranged in the rotation direction of the metal rotor 5. The metal portion 15 corresponds to a metal portion of the rotor body 6 that can face the first absolute angle detection coil 11 when the metal rotor 5 is rotated, for example. The metal part 15 (metal rotor 5) is preferably formed of a magnetic material, for example.

  The recesses 8 forming the first magnetic field change imparting portion 14a are preferably formed by changing the depths of the remaining four locations of the five recesses 8 except for one location. That is, it is preferable that the recessed part 8 which makes the 1st magnetic field change provision part 14a is a notch formed by, for example, removing the bottom of the recessed part 8. The plurality of recesses 8 are preferably provided so as to change in size step by step in the rotation direction of the metal rotor 5. The size of the recess 8 corresponds to the depth of the notch if the recess 8 is a notch. In the case of this example, the first concave portion 8a, the second concave portion 8b, the third concave portion 8c, and the fourth concave portion 8d are formed in order of increasing depth. Incidentally, the recess 8 is not limited to the notch, and may be changed to a hole or a hole, for example.

  The second absolute angle detection coil 13 is preferably formed from, for example, one winding part (coil winding). The second absolute angle detection coil 13 is preferably arranged at a position closer to the inner side than the first absolute angle detection coil 11 in the radial direction of the metal rotor 5, that is, a position closer to the rotation center P. The first absolute angle detection coil 11 and the second absolute angle detection coil 13 are preferably disposed inside the excitation coil 3 and the specific range angle detection coil 4 in the radial direction of the metal rotor 5.

  The second magnetic field change imparting portion 14 b preferably includes the metal portion 16 of the metal rotor 5 and one concave portion 17 formed in the metal rotor 5. The metal portion 16 corresponds to a metal portion of the rotor body 6 that can face the second absolute angle detection coil 13 when the metal rotor 5 rotates. The metal part 16 (metal rotor 5) is preferably formed of a magnetic material, for example. The concave portion 17 of the second magnetic field change imparting portion 14b is preferably a hole or a hole, for example. For example, the recess 17 is preferably arranged at a position closer to the inner side than the first absolute angle detection coil 11 in the radial direction of the metal rotor 5, that is, a position closer to the rotation center P.

  As shown in FIG. 2, the winding portion 12 formed by arranging a plurality of pairs is arranged so that the one arranged on one side (the left side of the paper) is along one side wall 10 of the projecting piece 7, and the other side It is preferable that the ones arranged on the side (the right side of the drawing) are arranged along the other side wall 9 of the projecting piece 7. Specifically, the winding portions 12 a, 12 c, 12 e, and 12 g are arranged along the side wall 10, and the winding portions 12 b, 12 d, 12 f, and 12 h are arranged along the side wall 9. The setting angle Ra formed by the winding portions 12a, 12c, 12e, and 12g and the winding portions 12b, 12d, 12f, and 12h is preferably, for example, “36 °” in accordance with the setting angle R1 of the protruding piece 7.

  As shown in FIG. 3, the setting angle Rb in the rotor rotation plane of the winding portions 12a, 12c, 12e, and 12g is, for example, 1/3 of the setting angle R1 (R2) of the projecting piece 7 (concave portion 8). preferable. That is, the set angle Rb is preferably about “12 °”, for example. The set angle Rc in the rotor rotation plane of the winding portions 12b, 12d, 12f, and 12h is, for example, 1/3 of the set angle R1 (R2) of the projecting piece 7 (recessed portion 8) (about “12 °”). preferable.

  The winding portions 12 a, 12 c, 12 e, and 12 g are preferably formed such that the coil diameter increases in order toward the radially outer side of the metal rotor 5. Similarly, the winding portions 12 b, 12 d, 12 f, and 12 h are preferably formed so that the coil diameter sequentially increases toward the radially outer side of the metal rotor 5. In the winding portions 12a to 12h, the winding is preferably formed in a substantially square shape, for example. In the case of this shape, when L1 and L2 are a pair of straight lines that form an acute angle extending from the rotation center P of the metal rotor 5, one side 20 of the winding portions 12a, 12c, 12e, and 12g is on the line L1. It is preferable that the other side 21 opposite to this rides on the line L2. When another pair of straight lines having an acute angle extending from the rotation center P of the metal rotor 5 is L3 and L4, one side 22 of the winding portions 12b, 12d, 12f, and 12h is placed on the line L3. It is preferable that the other side 23 facing this is on the line L4.

  The second absolute angle detection coil 13 is preferably arranged with a predetermined amount of deviation from the first absolute angle detection coil 11 in the rotation direction of the metal rotor 5. The set angle Rd formed by the first absolute angle detection coil 11 and the second absolute angle detection coil 13 is preferably about “36 °”, for example. The set angle Re in the rotor rotation plane of the absolute angle detection coil 13 is preferably ½ of the set angle R1 (R2) of the projecting piece 7 (recess 8), for example. That is, the set angle Re is preferably about “18 °”, for example. The setting angle Rf of the concave portion 17 in the rotor rotation direction is preferably about “30 °”, for example.

  As illustrated in FIG. 4, the position detection device 2 includes a position calculation unit 24 that calculates the position of the movable object 1 based on a combination of detection signals input from the specific range angle detection coils 4 a to 4 c and the absolute angle detection coils 11 and 13. Is provided. The position calculation unit 24 is preferably connected to the excitation coil 3 via the excitation circuit 25. A voltage adjusting resistor 26 is preferably connected to the high potential side of the exciting coil 3. The specific range angle detection coils 4a to 4c are preferably connected to the position calculation unit 24 via detection circuits 27 to 29, respectively. The detection circuits 27 to 29 are preferably circuits that perform amplification or modulation, for example.

  The position calculation unit 24 generates a magnetic field (magnetic flux) from the excitation coil 3 by applying an AC voltage to the excitation coil 3, and generates an induced electromotive force in the specific range angle detection coils 4a to 4c by mutual induction. . At this time, the position calculation unit 24 inputs the first specific range angle signal S1-a from the first specific range angle detection coil 4a through the detection circuit 27, and the second specific range angle detection coil 4b from the second specific range angle detection coil 4b through the detection circuit 28. The specific range angle signal S1-b is input, and the third specific range angle signal S1-c is input from the third specific range angle detection coil 4c through the detection circuit 29.

  The first absolute angle detection coil 11 and the second absolute angle detection coil 13 are preferably self-excited, for example. In this case, the position calculation unit 24 is connected to a series circuit composed of the voltage adjustment resistor 31 and the winding portions 12a to 12h through the excitation circuit 30, and the voltage adjustment resistor through the excitation circuit 32. It is preferably connected to a series circuit composed of 33 and the second absolute angle detection coil 13. The absolute angle detection coils 11 and 13 preferably output detection signals to the position calculation unit 24 via detection circuits 34 and 35, respectively. The detection circuits 34 and 35 are preferably circuits that perform amplification and modulation, for example.

  The position calculation unit 24 applies an AC voltage to the excitation coil 3 and causes the absolute angle detection coils 11 and 13 to change the inductance according to the rotational position of the metal rotor 5. The position calculation unit 24 inputs the first absolute angle signal Sa from the first absolute angle detection coil 11 through the detection circuit 34 and inputs the second absolute angle signal Sb from the second absolute angle detection coil 13 through the detection circuit 35.

  The position calculation unit 24 determines the rotation position of the movable object 1, that is, the rotation angle of the metal rotor 5 (rotor angle) by combining the specific range angle signals S1-a, S1-b, S1-c and the absolute angle signals Sa, Sb. θ) is calculated. That is, the position calculation unit 24 combines the position detection result based on the outputs of the specific range angle detection coils 4 a to 4 c and the position detection result based on the outputs of the absolute angle detection coils 11 and 13, thereby moving the movable object 1. Is calculated.

Next, operation | movement of the position detection apparatus 2 is demonstrated using FIGS.
[Angle detection operation by specific range angle detection coil]
As shown in FIG. 5, when an AC voltage is applied to the excitation coil 3, induced electromotive forces are generated in the three specific range angle detection coils 4a to 4c by mutual induction. In this state, when the metal rotor 5 rotates around the rotation center P, the detection voltage (amplitude) of each of the specific range angle detection coils 4a to 4c varies depending on the position of the projecting piece 7 of the metal rotor 5 (for example, an AC waveform) It changes to a sine wave or triangular wave. That is, when the first specific range angle signal S1-a output from the first specific range angle detection coil 4a is used as a reference, the second specific range whose phase is delayed by “24 °” from the second specific range angle detection coil 4b. The angle signal S1-b is output, and the third specific range angle signal S1-c whose phase is “24 °” earlier is output from the third specific range angle detection coil 4c.

  The position calculation unit 24 uses two (three in this example) specific range angle signals S1-a, S1-b, S1-c whose signal waveform is linear (exists in the region U). The detected angle θr corresponding to the rotational position of the movable object 1 is calculated by taking, for example, the difference or sum of these signals. For example, when the rotor angle θ is 6 ° to 18 °, S1-a and S1-b are used, and when the rotor angle θ is 18 ° to 30 °, S1-a and S1-c are used. In this way, the position calculation unit 24 can calculate the detection angle θr in which one cycle is 72 °.

[Angle detection operation of 0 ° ≦ θ <72 °]
As shown in FIG. 6, it is assumed that the position detection device 2 at the left end in FIG. 6 is set to “0 °” as a reference, and the metal rotor 5 is rotated from this reference position. When 0 ° ≦ θ <72 °, the detection voltages (specific range angle signals S1-a to S1-c) output from the specific range angle detection coils 4a to 4c are the same rule as in the example illustrated in FIG. Take the voltage change of sex. That is, the specific range angle signals S1-a to S1-c have a phase shift of 24 ° between S1-a and S1-b and a phase of 24 ° between S1-a and S1-c, with 72 ° being one cycle. Output as a shifted signal.

  In the range of 0 ° ≦ θ <72 °, the second absolute angle detection coil 13 moves away from the concave portion 17 in the range of 0 ° to 18 °, and is gradually covered by the metal rotor 5 (metal portion 16). become. For this reason, the second absolute angle detection coil 13 outputs a detection voltage (second absolute angle signal Sb) that gradually decreases from 0 ° to 18 ° and thereafter becomes constant. In the same range, in the first absolute angle detection coil 11, the first recess 8a is located at a position facing the winding portion 12a in the range of 62 ° to 72 °, and the winding portion 12a is the metal rotor 5 (metal portion 15). ) Will not be covered. For this reason, the first absolute angle detection coil 11 gradually increases from 62 ° to 72 °, which is initially constant, and a detection voltage (first absolute angle signal Sa) that finally becomes V1. Is output.

  The position calculation unit 24 calculates the rotor angle θ in the range of 0 ° ≦ θ <72 ° by a combination of the specific range angle signals S1-a to S1-c and the absolute angle signals Sa and Sb. That is, the position calculation unit 24 uses 0 ° ≦ θ <72 ° by the specific range angle signals S1-a to S1-c and the absolute angle signals Sa and Sb that take a combination of unique values for each period of 72 °. The rotor angle θ in the range is calculated.

[Angle detection operation of 72 ° ≦ θ <144 °]
As shown in FIG. 7, it is assumed that the metal rotor 5 is rotated in a range of 72 ° ≦ θ <144 °. In the same range, the detection voltages (specific range angle signals S1-a to S1-c) output from the specific range angle detection coils 4a to 4c have the same voltage change as in FIG.

  In the range of 72 ° ≦ θ <144 °, for example, when θ exceeds 98 °, a part of the winding portion 12a begins to be covered by the metal rotor 5, but conversely, the winding portion 12b is now covered by the metal rotor 5. Since it is no longer covered, the state in which one winding is not covered with the metal rotor 5 is maintained as a whole. In the first absolute angle detection coil 11, in addition to the winding portion 12 a, another winding portion 12 c is not covered with the metal rotor 5 (metal portion 15) in the range of 134 ° to 144 °. For this reason, the first absolute angle detection coil 11 initially takes a constant V1, but gradually increases from 134 ° to 144 °, and finally becomes a detection voltage (first absolute angle signal Sa) that becomes V2. ) Is output. In the same range, the second absolute angle detection coil 13 is kept covered with the metal rotor 5 (metal part 16). Therefore, even in the same range, the second absolute angle detection coil 13 continues to output a detection voltage (second absolute angle signal Sb) having the same value as when 0 ° ≦ θ <72 °.

  The position calculation unit 24 calculates the rotor angle θ in the range of 72 ° ≦ θ <144 ° by a combination of the specific range angle signals S1-a to S1-c and the absolute angle signals Sa, Sb. That is, the position calculation unit 24 uses the specific range angle signals S1-a to S1-c and the absolute angle signals Sa and Sb that take a combination of unique values for each 72 ° period, so that 72 ° ≦ θ <144 °. The rotor angle θ in the range is calculated.

[Angle detection operation of 144 ° ≦ θ <288 °]
The angle detection operation of 144 ° ≦ θ <288 ° is basically the same as the angle detection operation of 0 ° ≦ θ <72 ° and the angle detection operation of 72 ° ≦ θ <144 ° described above. The description is omitted.

[Angle detection operation at 288 ° ≦ θ <360 °]
As shown in FIG. 8, it is assumed that the metal rotor 5 is rotated in a range of 288 ° ≦ θ <360 °. Even in the same range, the detection voltages (specific range angle signals S1-a to S1-c) output from the specific range angle detection coils 4a to 4c have the same voltage change as in FIG.

  In the range of 288 ° ≦ θ <360 °, the second absolute angle detection coil 13 has the concave portion 17 opposed to the range of 330 ° to 348 ° and is not covered with the metal rotor 5 (metal portion 16). For this reason, the second absolute angle detection coil 13 outputs a detection voltage (second absolute angle signal Sb) that is initially constant but gradually increases from 330 ° to 348 °. When θ exceeds 348 °, the second absolute angle signal Sb takes a constant value. In the same range, all the winding portions 12a to 12h of the first absolute angle detection coil 11 are covered with the metal rotor 5 (metal portion 15) in the range of 350 ° to 360 °. For this reason, the first absolute angle detection coil 11 outputs a detection voltage (first absolute angle signal Sa) that gradually decreases from 350 ° to 360 °, although it initially takes a constant value.

  The position calculation unit 24 calculates the rotor angle θ in the range of 288 ° ≦ θ <360 ° by a combination of the specific range angle signals S1-a to S1-c and the absolute angle signals Sa, Sb. In other words, the position calculation unit 24 uses the specific range angle signals S1-a to S1-c and the absolute angle signals Sa and Sb that take a combination of unique values for each period of 72 °, so that 288 ° ≦ θ <360 °. The rotor angle θ in the range is calculated.

[Summary of angle detection operation from 0 ° to 360 °]
FIG. 9 illustrates a summary of angle detection from 0 ° to 360 °. The output combinations of the two absolute angle detection coils 11 and 13 are “0 ° to 72 °”, “72 ° to 144 °”, “144 ° to 216 °”, “216 ° to 288 °”, “288 ° to” It can be seen that every 360 ° takes a different pattern. For this reason, even if the output combination of the three specific range angle detection coils 4a to 4c is repeated every 72 °, the combination of the two absolute angle detection coils 11 and 13 is identified to identify them. It is possible. Therefore, as in this example, if the angle is detected using the three specific range angle detection coils 4a to 4c and the two absolute angle detection coils 11 and 13, one rotation of 0 to 360 ° can be detected. Is possible.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) For example, consider a method in which the first absolute angle detection coil 11 and the second absolute angle detection coil 13 are omitted, and the rotational position of the movable object 1 is detected only by the specific range angle detection coil 4. In this case, the angle of the movable object 1 can be detected only in the range of 0 ° to 72 ° which is the detection range (loop angle Rk) of the specific range angle detection coil 4. On the other hand, in the case of this example, the first absolute angle detection coil 11 and the second absolute angle detection coil 13 are provided in the position detection device 2, and the output of the specific range angle detection coil 4 and the output of the absolute angle detection coils 11 and 12 Thus, the rotational position of the movable object 1 is determined, so that the angle of the movable object 1 can be detected in a wider range than when only the specific range angle detection coil 4 is used. Therefore, when detecting the position of the movable object 1, the detection range can be widened.

  (2) Each specific range angle detection coil 4 is a coil having a narrow angle with a loop angle Rk of 72 °. In the case of this example, even when such a narrow-angle coil is used, the position of the movable object 1 can be detected at 360 °.

(3) Since the metal body which is the object of position detection is the metal rotor 5, the rotation position of the metal rotor 5 can be detected in a wide range (0 ° to 360 °).
(4) A plurality of sets of winding portions 12 are arranged in the radial direction of the metal rotor 5. Therefore, since it becomes easy to output the optimal signal according to the rotation position of the movable object 1 from the first absolute angle detection coil 11, it is advantageous for ensuring the accuracy of position detection.

  (5) The magnetic field change application unit 14 includes a first magnetic field change application unit 14a for the first absolute angle detection coil 11 and a second magnetic field change application unit 14b for the second absolute angle detection coil 13. As described above, since the magnetic field change applying unit 14 is provided in each of the first absolute angle detection coil 11 and the second absolute angle detection coil 13, it is suitable for the first absolute angle detection coil 11 and the second absolute angle detection coil 13, respectively. It becomes easy to apply a magnetic field of change.

  (6) The magnetic field change imparting portion 14 includes metal portions 15 and 16 provided on the metal rotor 5 and concave portions 8 and 17. Therefore, when the magnetic field change imparting portion 14 is provided in the metal rotor 5, it can be realized with a simple structure in which the metal portions 15 and 16 and the concave portions 8 and 17 are provided in the metal rotor 5.

  (7) The winding portions 12 formed by arranging a plurality of pairs are arranged so that the ones (12a, 12c, 12e, 12g) arranged on one side are along one side wall 10 of the projecting piece 7, and the other (12b, 12d, 12f, 12h) that are arranged on the side of the projection 7 are arranged along the other side wall 9 of the projecting piece 7. Therefore, it is advantageous for switching which winding portions 12a to 12h are covered with the metal portions 15 and 16 and which winding portions 12a to 12h are covered with the concave portions 8 and 17 with high accuracy.

  (8) The plurality of winding portions 12 are formed such that the coil diameter sequentially increases toward the radially outer side of the metal rotor 5. Therefore, it is more advantageous to switch which winding portions 12a to 12h are covered with the metal portions 15 and 16 and which winding portions 12a to 12h are covered with the recesses 8 and 17 with high accuracy.

  (9) The first absolute angle detection coil 11 and the second absolute angle detection coil 13 are disposed inside the excitation coil 3 and the specific range angle detection coil 4 in the radial direction of the metal rotor 5. Therefore, the absolute angle detection coils 11 and 13 can be small in size.

  (10) The position calculation unit 24 selects two of the plurality of specific range angle signals S1-a to S1-c that have a linear signal waveform, and calculates the position of the movable object 1 from these signals. . Therefore, it is possible to detect the position with the component that linearly changes in the specific range angle signals S1-a to S1-c, which is advantageous for accurately determining the position of the movable object 1.

Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.
The excitation coil 3 may take a shape pattern that covers only a part of the specific range angle detection coil 4. Moreover, the shape pattern which is not covered at all may be sufficient.

The excitation coil 3 may take a shape pattern that covers the absolute angle detection coil 11.
A plurality of gaps are formed in the outer periphery of the metal rotor 5, and a desired signal is output from the specific range angle detection coil 4 depending on the presence or absence of the projecting pieces 7 and the gaps arranged at equal intervals in the rotation direction of the metal rotor 5. May be output.

-The recessed parts 8 and 17 are not limited to the shape formed by notching the outer periphery of the metal rotor 5. FIG. For example, the recesses 8 a to 8 d may be holes penetrating in the axial direction of the metal rotor 5.
The specific range angle detection coils 4a to 4c may have a shape in which the coil pattern is not overlapped in the thickness direction of the substrate.

The absolute angle detection coil 11 may be arranged outside the excitation coil 3 and the specific range angle detection coil 4 in the radial direction of the metal rotor 5.
The number of the specific range angle detection coil 4 and the absolute angle detection coil 11 can be appropriately changed to various numbers.

The number of sets of the winding portions 12 of the first absolute angle detection coil 11 is not limited to four sets, and other number of sets may be adopted.
The shape and size of the specific range angle detection coil 4 and the absolute angle detection coil 11 can be appropriately changed to values other than those described in the embodiment.

The period of the specific range angle signal S1 and the absolute angle signals Sa and Sb can be appropriately changed to values other than those described in the embodiment.
The magnetic field change applying unit 14 may have a structure (shape) in which the first magnetic field change applying unit 14a and the second magnetic field change applying unit 14b are integrated.

The absolute angle detection coil 11 is not limited to the self-excited type but may be a separately excited type.
The magnetic field change applying unit 14 can adopt various structures and shapes as long as the magnetic field applied to the absolute angle detection coils 11 and 13 can be changed.

  In the first absolute angle detection coil 11, for example, the winding portions 12a, 12c, 12e, and 12g are formed from one winding portion, and the winding portions 12b, 12d, 12f, and 12h are formed from one winding portion. May be.

The position detection device 2 may detect the position of 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 angle detection coil, 5 ... Metal rotor which is an example of a metal body, 7 ... Projection piece, 8, 17 ... Recessed part , 9, 10 ... side wall of the projecting piece, 11 ... first absolute angle detection coil, 12 (12a to 12h) ... winding part, 13 ... second absolute angle detection coil, 14 ... magnetic field change imparting part, 14a ... first Magnetic field change imparting section, 14b ... second magnetic field change imparting section, 15, 16 ... metal part, 24 ... position calculating section, S1 ... specific range angle signal, Sa ... first absolute angle signal, Sb ... second absolute angle signal, A: Turning direction of the metal rotor, which is an example of the moving direction of the movable object.

Claims (9)

An excitation coil through which a current flows, one or more specific range angle detection coils capable of detecting a magnetic field generated from the excitation coil, and the specific range angle detection coil according to the position of a movable object that is a position detection target In a position detection device comprising a metal body that changes a magnetic field to be
A first absolute angle detection coil comprising at least one set of a plurality of winding portions arranged in the moving direction of the movable object;
A second absolute angle detection coil that outputs a detection signal having a phase different from that of the first absolute angle detection coil;
A combination constructed from the first absolute angle signal output from the first absolute angle detection coil and the second absolute angle signal output from the second absolute angle detection coil is output from the specific range angle detection coil. In order to change the magnetic field applied to the first absolute angle detection coil and the second absolute angle detection coil so as to take different combinations for each period of position detection based on the specific range angle signal of the AC wave Formed magnetic field change imparting portion;
A position detection apparatus comprising: a position calculation unit that calculates a position of the movable object by a combination of the specific range angle signal, the first absolute angle signal, and the second absolute angle signal. The metal body is a metal rotor that interlocks with the rotating movable object, and the plurality of winding portions in the same set are arranged side by side in the rotation direction of the metal rotor, and the position calculation unit is the movable The position detection apparatus according to claim 1, wherein the rotation position of the animal is calculated. The position detecting device according to claim 2, wherein a plurality of sets of the winding portions are arranged side by side in the radial direction of the metal rotor. The magnetic field change applying unit includes a first magnetic field change applying unit that changes a magnetic field applied to the first absolute angle detection coil, and a second magnetic field change application that changes a magnetic field applied to the second absolute angle detection coil. The position detecting device according to any one of claims 1 to 3, further comprising a unit. The first magnetic field change imparting unit includes a metal part of a metal rotor and a plurality of recesses arranged in a rotation direction of the metal rotor,
The position detecting device according to claim 4, wherein the plurality of concave portions are provided so as to sequentially change in size in the rotation direction of the metal rotor. A pair of the winding portions are provided in the same set, and a plurality of sets are provided so that this set is aligned in the radial direction of the metal rotor,
The winding portions formed by arranging a plurality of pairs are arranged so that the protrusions formed on the metal rotor are arranged on one side along one side wall of the protrusion, and the other side. The position detecting device according to claim 5, wherein those arranged in a line are arranged along the other side wall of the protruding piece. The position detecting device according to any one of claims 3 to 6, wherein the winding portion is formed so that a coil diameter sequentially increases toward a radially outer side of the metal rotor. . The first absolute angle detection coil and the second absolute angle detection coil are arranged inside the excitation coil and the specific range angle detection coil in a radial direction of the metal rotor. The position detection apparatus as described in any one of them. The position calculating unit selects two signals having a linear signal waveform from among a plurality of specific range angle signals, and calculates the position of the movable object from these signals. The position detection apparatus as described in any one of them.