WO2014156275A1 - Système capteur de proximité - Google Patents

Système capteur de proximité Download PDF

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Publication number
WO2014156275A1
WO2014156275A1 PCT/JP2014/051853 JP2014051853W WO2014156275A1 WO 2014156275 A1 WO2014156275 A1 WO 2014156275A1 JP 2014051853 W JP2014051853 W JP 2014051853W WO 2014156275 A1 WO2014156275 A1 WO 2014156275A1
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WIPO (PCT)
Prior art keywords
resonance
frequency
unit
circuit unit
oscillation
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PCT/JP2014/051853
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English (en)
Japanese (ja)
Inventor
鈴木　慎一郎
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アズビル株式会社
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Publication of WO2014156275A1 publication Critical patent/WO2014156275A1/fr

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/945—Proximity switches
    • H03K17/95—Proximity switches using a magnetic detector
    • H03K17/952—Proximity switches using a magnetic detector using inductive coils
    • H03K17/953—Proximity switches using a magnetic detector using inductive coils forming part of an oscillator
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness
    • G01B7/023—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness for measuring distance between sensor and object

Definitions

  • Some embodiments according to the present invention relate to, for example, a high-frequency oscillation type proximity sensor system.
  • a proximity sensor of this type in a proximity switch including a detection signal processing printed circuit board housed along the longitudinal direction of the case, a display element for displaying the operation state of the switch is provided on one side of the printed circuit board. What was provided is known (for example, refer patent document 1). According to this proximity switch, the display element is not mounted in the substantially central portion in the width direction of the printed circuit board, but is mounted on one side in the width direction of the circuit board, so that the discrete LED is not mounted on the printed circuit board. The lighting of the display element can be easily confirmed from the outside of the switch.
  • the detection distance capable of detecting the proximity (presence / absence) of the detection target is proportional to the length of the diameter of the detection surface that generates magnetic flux and forms a magnetic field. Therefore, when increasing the detection distance, it is necessary to increase the diameter of the detection surface, and as a result, the size (size or dimension) of the proximity sensor is increased.
  • Some aspects of the present invention have been made in view of the above-described problems, and an object thereof is to provide a proximity sensor system that can increase the detection distance without changing the size.
  • a proximity sensor system is a proximity sensor system that detects the proximity of an object to be detected, the sensor unit including an oscillation circuit unit that forms a magnetic field at a predetermined oscillation frequency, and the object to be detected. And a detected unit including a resonance circuit unit having a resonance frequency based on the predetermined oscillation frequency.
  • the sensor unit 10 including an oscillation circuit unit that forms a magnetic field at a predetermined oscillation frequency and the detected unit including a resonance circuit unit having a resonance frequency based on the predetermined oscillation frequency of the sensor unit are provided.
  • the oscillation circuit unit forms a magnetic field at a predetermined oscillation frequency and the resonance circuit unit has a resonance frequency based on the predetermined oscillation frequency
  • the resonance circuit unit resonates.
  • the resonant circuit portion that resonates even when the change in the magnetic field (or magnetic flux of the magnetic field) is slight, a large voltage is generated compared to the case where the resonance circuit unit does not resonate (non-resonant).
  • the electric power (energy) consumed by the resonance circuit unit gives energy loss to the oscillation circuit unit.
  • the resonance circuit section of the detected unit provided in the detected body gives energy loss to the oscillation circuit section, and a predetermined value of the oscillation circuit section, for example, Q value, oscillation frequency, oscillation amplitude, internal resistance of the detection coil Since values such as inductance, impedance, and the like change, it is possible to detect the proximity of the detection target.
  • the resonance circuit section of the detected unit provided in the detected object gives energy loss to the oscillation circuit section of the sensor unit, and the proximity of the detected object is detected using the energy loss. Therefore, even if the object to be detected is a nonmagnetic material, energy loss can be given to the oscillation circuit unit, and the object to be detected that is a nonmagnetic material can be detected.
  • the resonance distance of the detected unit provided on the detected object not the detected object itself, causes energy loss due to the change of the magnetic field (magnetic flux of the magnetic field), so that the detection distance depends on the type of detected object. It does not depend on (the detection distance does not change depending on the type of the object to be detected).
  • the resonance circuit unit includes a resistor, a coil, and a capacitor.
  • the resonance circuit unit includes a resistor, a coil, and a capacitor.
  • the resonance frequency of the resonance circuit unit can be calculated using the inductance of the coil and the capacitance of the capacitor. Therefore, by setting the inductance of the coil and the capacitance of the capacitor based on the predetermined oscillation frequency of the oscillation circuit unit, a resonance circuit unit having a resonance frequency based on the predetermined oscillation frequency can be easily configured (realized). Can do.
  • the frequency characteristic of the Q value of the resonance circuit section can be changed by changing the resistance of the resistor. Therefore, by setting the resistance of the resistor according to the usage mode (purpose of use), the frequency characteristic of the Q value of the resonance circuit unit can be set to a desired characteristic without changing the resonance frequency.
  • the aforementioned resistor is a variable resistor.
  • the resonant circuit unit includes the variable resistor.
  • the Q value of the resonance circuit section is widened with a large Q value in a wide frequency band by changing the resistance of the variable resistor to a relatively large value. Therefore, the resonance circuit unit can absorb an error of a predetermined oscillation frequency. Therefore, even when the error of the predetermined oscillation frequency is large, the Q value of the resonance circuit portion of the detected unit can be increased, and the proximity of the detected object can be detected.
  • the Q value of the resonant circuit section is narrowed to a large Q value in a narrow frequency band. Frequency characteristics and a large maximum value in the vicinity of the resonance frequency. Therefore, even when the change of the magnetic field (or magnetic flux of the magnetic field) is slight (small), the Q value of the resonance circuit section of the detected unit can be increased, and the Q value of the oscillation circuit section changes (decreases) greatly. The detection distance can be further increased.
  • the aforementioned capacitor is a variable capacitor.
  • the resonant circuit unit includes the variable capacitor.
  • the capacitance of the variable capacitor changes the resonance frequency, changing the capacitance of the variable capacitor shifts the resonance frequency that is the center line (center axis) in the frequency characteristic of the Q value of the resonance circuit ( Move). Therefore, when the error of the predetermined oscillation frequency is positive, the frequency characteristic of the Q value of the resonance circuit unit can be shifted in the positive direction by changing the capacitance of the variable capacitor to a small value.
  • the frequency characteristic of the Q value of the resonance circuit unit can be shifted in the negative direction by changing the capacitance of the variable capacitor to a small value. Therefore, when the error of the predetermined oscillation frequency or the actual predetermined oscillation frequency itself is known, the resonance circuit of the detected unit can be resonated, and the proximity of the detected object can be detected while maintaining the detection distance. can do.
  • the detected unit includes a non-magnetic housing that houses the resonance circuit unit.
  • the detected unit includes a non-magnetic housing that houses the resonance circuit unit.
  • the magnetic flux generated by the oscillation circuit unit can be applied to the resonance circuit unit, and the resonance circuit unit can be protected from the external environment. Therefore, the detected unit can improve the environmental resistance performance such as water resistance, oil resistance, dirt resistance, vibration resistance, shock resistance, heat resistance, cold resistance, etc., and the proximity sensor system is required to be environmental resistance. It can be suitably applied to the use.
  • the oscillation circuit unit includes a coil and a capacitor.
  • the oscillation circuit unit includes the coil and the capacitor.
  • the coil when a current flows through the coil at a predetermined oscillation frequency, the coil generates a magnetic flux, and forms a magnetic field (magnetic field) between the sensor unit and the detection target.
  • a magnetic field magnetic field
  • an oscillation circuit unit that forms a magnetic field at a predetermined oscillation frequency can be easily configured (realized).
  • the resonance frequency of a resonance circuit composed of a coil and a capacitor can be calculated using the inductance of the coil and the capacitance of the capacitor. Therefore, by setting the predetermined oscillation frequency of the oscillation circuit unit to be the same as the calculated resonance frequency, the impedance of the resonance circuit can be maximized and the power consumption of the oscillation circuit unit can be reduced.
  • the detection distance can be doubled or more compared with a conventional proximity sensor having the same detection surface diameter, and the detection distance can be changed without changing the size of the sensor unit. Can be lengthened.
  • the proximity sensor system can reduce the diameter of the detection surface and reduce the size of the sensor unit as compared with a conventional proximity sensor having the same detection distance.
  • FIG. 6 is a circuit diagram for explaining still another example of the detected unit shown in FIG. 1.
  • FIG. 6 is a circuit diagram for explaining still another example of the detected unit shown in FIG. 1.
  • FIG. 1 is a configuration diagram illustrating a schematic configuration of the proximity sensor system 100.
  • the proximity sensor system 100 is for detecting the proximity or presence of the detection target A without contacting the detection target A that is a detection target.
  • the proximity sensor system 100 includes a sensor unit 10 and a detected unit 50.
  • Sensor unit 10 is a non-contact type detection means.
  • the sensor unit 10 has a detection surface (left end surface in FIG. 1) having a diameter M (hereinafter simply referred to as a diameter) M.
  • the detected unit 50 is formed in a plate shape (plate shape), for example, and is provided on the surface of the detected object A (the right end surface in FIG. 1).
  • the proximity sensor system 100 determines the proximity (presence / absence) of the detection target A when the distance between the detection surface of the sensor unit 10 and the surface of the detection unit provided on the detection target A is equal to or less than the detection distance D. It becomes possible to detect.
  • the sensor unit 10 includes a case 11, a cover 12, a detection coil 21, a printed circuit board 13, and a cable 14.
  • the case 11 is, for example, a metal cylindrical or substantially cylindrical cylinder. Inside the case 11, the detection coil 21, the printed circuit board 13, and one end of the cable 14 (left end in FIG. 1) are accommodated.
  • a cover 12 is attached to the opening end of the case 11 (left end in FIG. 1).
  • the cover 12 is a nonconductive member made of resin, for example, and covers the open end side (left side in FIG. 1) of the detection coil 12.
  • the detection coil 21 is, for example, a core coil type inductor, and includes a core 21a made of a magnetic material and an electromagnetic coil 21b wound around the core 21a.
  • the printed circuit board 13 includes, for example, an oscillation circuit 25 and a detection circuit unit 30.
  • the oscillation circuit 25 is electrically connected to the detection coil 21 and electrically connected to the detection circuit unit 30.
  • the detection coil 21 and the oscillation circuit 25 constitute an oscillation circuit unit 20 described later.
  • the detection circuit unit 30 is for determining the proximity (presence / absence) of the detection target A based on a signal (output signal) output from the oscillation circuit unit 20. For example, the detection circuit unit 30 determines the proximity of the detection target A based on the Q value of the oscillation circuit unit 20.
  • the printed circuit board 13 may further include a display circuit, an output circuit, a signal amplifier circuit, and the like.
  • the present invention is not limited to this.
  • the sensor unit 10 may have a so-called unshielded structure in which the detection coil 21 is exposed by protruding from the case 11 to the detected object A side (left side in FIG. 1).
  • FIG. 2 is a circuit diagram illustrating an example of an equivalent circuit of the oscillation circuit unit 20.
  • the oscillation circuit unit 20 includes a detection coil 21 and an oscillation circuit 25.
  • Oscillator circuit 25 is used for oscillating driving the detection coil 21 at a predetermined oscillation frequency f 0.
  • the oscillation circuit 25 includes, for example, an oscillation capacitor (capacitor) 26, a bias circuit 27, a current mirror circuit 28, and a voltage-current conversion circuit 29.
  • the oscillation circuit 25 includes an output terminal 25a and an output terminal 25b connected to the detection circuit unit 30 shown in FIG.
  • the detection coil 21 and the oscillation capacitor 26 of the oscillation circuit 25 constitute an LC oscillation circuit 20A, and the detection coil 21 and the oscillation capacitor 26 are connected in parallel.
  • the bias circuit 27 is configured to include a current source 27a, and a transistor Tr 1.
  • the LC oscillation circuit 20A When a predetermined bias current Ib is supplied from the bias circuit 27, the LC oscillation circuit 20A generates a voltage V T indicated by a double arrow in FIG. Voltage V T generated in the LC oscillator circuit 20A is applied to the base of the transistor Tr 2 of the voltage-current converting circuit 29 through the transistor Tr 1 in the bias circuit 27.
  • Resistor 29a has its emitter of the transistor Tr 2, a line of a reference potential of the oscillation circuit 25 (ground), i.e., between the lines to be connected to the output terminal 25b in FIG. 2, are connected in series.
  • the resistor 29a functions as a resistor that sets a feedback current described later (plays a role of a feedback current setting resistor).
  • the collector current of the transistor Tr 2 of the voltage-current conversion circuit 29 flows to the transistor Tr 3 of the current mirror circuit 28.
  • the transistor Tr 3 and the transistor Tr 4 constitute a current mirror circuit 28.
  • Collector current I fb of the transistor Tr 4 is fed back (Ford back) to the LC oscillator circuit 20A as a feedback current mentioned above.
  • the output terminal 25a and the output terminal 25b are connected to both ends of the resistor 29a of the voltage-current conversion circuit 29, respectively.
  • the voltage V Re applied to the resistor 29 a indicated by the double arrow in FIG. 2 is output to the detection circuit unit 30 as a signal (output signal) of the oscillation circuit unit 20.
  • LC oscillation circuit 20A oscillates at a predetermined oscillation frequency f 0.
  • the detection coil 21 when a current flows through the detection coil 21 at a predetermined oscillation frequency f 0 , the detection coil 21 generates a magnetic flux and forms a magnetic field (magnetic field) between the sensor unit 10 and the detection target A.
  • the oscillation circuit 20 of the sensor unit 10 the magnetic field at a predetermined oscillation frequency f 0 is formed.
  • Detection coil 21 is the internal resistance R1 and inductance L1
  • the oscillation capacitor 26 is the capacitance (electrostatic capacitance) C1
  • the resonant frequency f 1 of the LC oscillator circuit 20A is expressed by the following equation (1) it can.
  • the unit of the resonance frequency f 1 is [Hz].
  • the oscillation circuit unit 20 the detection coil 21, by including the oscillation capacitor 26, the resonant frequency f 1 of the LC oscillator circuit 20A composed of a detection coil 21 and oscillator capacitor 26, Using the inductance L 1 of the detection coil 21 and the capacitance C 1 of the oscillation capacitor 26, it can be calculated by the equation (1).
  • the predetermined oscillation frequency f 0 of the oscillation circuit unit 20 is set to the same value as the resonance frequency f 1 calculated by Expression (1).
  • the predetermined oscillation frequency f 0 of the oscillation circuit unit 20 may be a predetermined frequency and is not limited to the same value as the resonance frequency f 1 .
  • the oscillation circuit unit 20 may form a magnetic field at a predetermined oscillation frequency f 0.
  • a known Colpitts oscillation circuit or the like may be used as the oscillation circuit unit 20.
  • the oscillation circuit unit 20 is not limited to a self-excited oscillation circuit, and may be a separately-excited oscillation circuit.
  • FIG. 3 is a circuit diagram for explaining an example of the detected unit 50 shown in FIG. As shown in FIG. 3, the detected unit 50 includes a housing 51 and a resonance circuit unit 60 accommodated in the housing 51.
  • the resonance circuit unit 60 includes a resonance resistor 61, a resonance coil (inductor) 62, and a resonance capacitor (capacitor) 63.
  • the resonance resistor 61, the resonance coil 62, and the resonance capacitor 63 are connected to each other in series.
  • the resonance circuit unit 60 has a resonance frequency f 2 based on the predetermined oscillation frequency f 0 of the oscillation circuit unit 20. That is, the resonant circuit 60, based on a predetermined oscillation frequency f 0 of the oscillator circuit unit 20, the resonance frequency f 2 is set. Specifically, the resonance frequency f 2 of the resonant circuit 60 is set to the same or substantially the same as the predetermined oscillation frequency f 0.
  • the resonance circuit unit 60 since the oscillation circuit unit 20 forms a magnetic field at the predetermined oscillation frequency f 0 and the resonance circuit unit 60 has the resonance frequency f 2 based on the predetermined oscillation frequency f 0 , the resonance circuit unit 60 resonates.
  • the resonant circuit unit 60 that resonates, even when the change of the magnetic field (or magnetic flux of the magnetic field) is slight, a large voltage is generated as compared with the case where it does not resonate (non-resonant).
  • the power (energy) consumed by the resonance circuit unit 60 gives energy loss to the oscillation circuit unit 20. Therefore, when the sensor unit 10 and the detected object A are close to each other, when the change of the magnetic field (or the magnetic flux of the magnetic field) is slight (small), that is, the detection distance D between the sensor unit 10 and the detected object A is conventional.
  • the resonance circuit unit 60 of the detected unit 50 provided in the detected object A gives energy loss to the oscillation circuit unit 20 even when the distance is longer than the predetermined value, for example, the Q value, the oscillation frequency of the oscillation circuit unit 20 Since the values such as the oscillation amplitude, the internal resistance R 1 , the inductance L 1 , and the impedance of the detection coil 21 change, the proximity of the detection target A can be detected.
  • the predetermined value for example, the Q value, the oscillation frequency of the oscillation circuit unit 20 Since the values such as the oscillation amplitude, the internal resistance R 1 , the inductance L 1 , and the impedance of the detection coil 21 change, the proximity of the detection target A can be detected.
  • the conventional proximity sensor of the high frequency oscillation type has, for example, a detection surface having a diameter m, and detects the proximity (presence / absence) of a detection object separated by a detection distance d.
  • the detection coil forms a magnetic field by the oscillation circuit unit.
  • the conventional proximity sensor detects the proximity (presence / absence) of the detection target by detecting a change in the Q value.
  • the eddy current does not flow or hardly flows even when subjected to the action of the magnetic flux, so that the object to be detected is limited to the magnetic material.
  • the detection distance d differs depending on the type of the detected object. For example, when the diameter m of the detection surface is 18 [mm], and iron is detected as the detection target, eddy current loss is likely to occur in iron, and the change in Q value is large, so the detection distance d is 7 to 8 It is possible to detect when [mm]. On the other hand, when the diameter m of the detection surface is 18 [mm] and aluminum is detected as the detection target, eddy current loss hardly occurs and the change in the Q value is small. It is possible to detect when the distance is 4 mm.
  • the flowing eddy current varies depending on the size (size or dimension) of the detection object, the shape of the detection surface, and the like, and as a result, the detection distance d also changes.
  • the resonance circuit unit 60 of the detected unit 50 provided in the detected object A gives energy loss to the oscillation circuit unit 20 of the sensor unit 10, and the energy loss ,
  • the proximity of the detected object A is detected, so that even if the detected object A is a non-magnetic material, energy loss can be given to the oscillation circuit unit 20, and the detected object is a non-magnetic material. A can be detected.
  • due to a change in the magnetic field (magnetic flux of the magnetic field) not the detected object A itself but the resonance circuit unit 60 of the detected unit 50 provided in the detected object A gives energy loss, so that the detection distance D is detected.
  • the detection distance D does not change depending on the type of the detected body A. Further, by using the resonance circuit unit 60 of the detected unit 50 provided on the detected object A, compared with the case of using the electromagnetic induction action or the eddy current loss due to the electromagnetic induction action as in the conventional proximity sensor. Further, it is possible to obtain an advantage (merit) that the detection target A is not easily affected by the size of the detection target A and the shape of the detection surface.
  • FIG. 4 is a graph showing the relationship between the frequency and the Q value for each detection distance D in the proximity sensor system 100 shown in FIG.
  • the horizontal axis represents the frequency f [Hz] of the oscillation circuit unit 20
  • the vertical axis represents the Q value of the oscillation circuit unit 20.
  • the graph G 40 does not include the detection target A, that is, the detection distance D is infinite
  • the graph G 41 has the detection distance D of 47 [mm]
  • the graph G 42 has the detection distance D of 35. If a [mm], a graph G 43 shows a case where the detection distance D is 27 [mm].
  • the value of the Q value of the oscillation circuit as a reference for detection shows a graphically H 4.
  • the graph G 40 the Q value of the oscillation circuit 20 is substantially constant at a relatively high value. That is, it means that the oscillation (vibration) of the oscillation circuit unit 20 is stable.
  • the resonance circuit unit 60 gives energy loss to the oscillation circuit unit 20 in the vicinity (near the vicinity) of the predetermined oscillation frequency f 0 , and the Q value of the oscillation circuit unit 20 decreases. Yes. All of the graphs G 41 to G 43 are below the threshold value indicated by the graph H 4 in the vicinity (near the oscillation frequency f 0 ).
  • FIG. 5 is a graph showing the relationship between the detection distance D and the Q value in the proximity sensor system 100 shown in FIG.
  • the horizontal axis represents the detection distance D
  • the vertical axis represents the Q value of the oscillation circuit unit 20.
  • a graph G 5 shows a case where the frequency of the oscillation circuit 20 is zero predetermined oscillation frequency f.
  • iron is used as the object to be detected.
  • a case where detection is performed and the frequency of the oscillation circuit is also the predetermined oscillation frequency f 0 0 is shown by a graph H 5 . As shown in FIG.
  • a conventional proximity sensor shown in the graph H 5 the value of Q value when the detection distance D is 20 [mm] is the threshold Q 0 or less, detects the proximity of the object to be detected It becomes possible to do.
  • the proximity sensor system 100 shown in the graph G 5 are detection distance D is 20 [mm], 35 [mm ], and 47 in all of the [mm], the threshold Q Q value of the oscillation circuit 20 is 0 Below. As a result, the proximity sensor system 100 can detect the proximity of the detection target A even when the detection distance d of the conventional proximity sensor is 20 [mm], which is more than twice [47] mm. It becomes possible.
  • the housing 51 shown in FIG. 3 is preferably a nonmagnetic housing made of a nonmagnetic material.
  • the material having nonmagnetic properties include aluminum (AL), stainless steel such as SUS304, copper (Cu), and the like. Accordingly, the magnetic flux generated by the oscillation circuit unit 20 can be applied to the resonance circuit unit 60, and the resonance circuit unit 60 can be protected from the external environment.
  • the resonance frequency f 2 in the resonance circuit unit 60 shown in FIG. 3 is that the resonance resistor 61 is the resistor R 2 , the resonance coil 62 is the inductance L 2 , and the resonance capacitor 63 is the capacitance (capacitance) C 2 . In some cases, it can be expressed by the following formula (2).
  • the unit of the resonance frequency f 2 is [Hz].
  • the resonance frequency f 2 of the resonance circuit unit 60 can be calculated by the equation (2) using the inductance L 2 of the resonance coil 62 and the capacitance C 2 of the resonance capacitor 63.
  • FIG. 6 is a graph showing the relationship between the frequency and the Q value in the resonance circuit unit 60 shown in FIG.
  • the horizontal axis represents the frequency f [Hz] of the resonant circuit unit 60
  • the vertical axis represents the Q value of the resonant circuit unit 60.
  • a graph G 61 shows a case when the resistance R 2 of the resonant resistor 61 is relatively large, the graph G 62 is the resonance resistance R 2 of the resistor 61 is relatively small.
  • the graph G 61 has a maximum Q value Q 61 and the graph G 62 has a maximum Q value Q 62 . .
  • the graph G 61 and the graph G 62 are symmetric or substantially symmetric curves with the resonance frequency f 2 as the center line (center axis).
  • the graph G 61 has a maximum value Q 61 smaller than the maximum value Q 62 of the graph G 62 , while the Q value is larger than that of the graph G 62 in the frequency band excluding the vicinity (near the resonance frequency f 2 ).
  • a graph G 61, the frequency band Delta] f 61 having a larger Q value than the predetermined value Q 60 is wider than the frequency band Delta] f 62 of the graph G 62.
  • the graph G 61 is a broadened curve that reduces the maximum Q value Q 61 while increasing the Q value in a wide frequency band.
  • the graph G 62 has a smaller Q value than the graph G 61 in the frequency band excluding the vicinity (near) the resonance frequency f 2, and a maximum value Q 62 larger than the maximum value Q 61 of the graph G 61.
  • the frequency band ⁇ f 62 having a Q value larger than the predetermined value Q 60 is narrower than the frequency band ⁇ f 61 of the graph G 61 . That is, the graph G 62 is a narrow band curve in which the maximum Q value Q 62 is increased while the Q value is large in a narrow frequency band.
  • the resistance R 2 of the resonance resistor 61 does not affect the resonance frequency f 2 as shown in the above-described equation (2), while the resonance resistor 61 has a resistance R 2 as shown in FIG.
  • the resistance R 2 By changing the resistance R 2 , it is possible to change the frequency characteristic of the Q value of the resonance circuit unit 60.
  • the example of the resonance circuit unit 60 including the resonance resistor 61, the resonance coil 62, and the resonance capacitor 63 is shown in FIG. 3, but the present invention is not limited to this.
  • a resonance circuit unit different from the resonator circuit unit 60 will be described.
  • FIG. 7 is a circuit diagram for explaining another example of the detected unit 50 shown in FIG. As shown in FIG. 7, the detected unit 50 includes a housing 51 and a resonance circuit unit 60 ⁇ / b> A housed inside the housing 51.
  • the resonance circuit unit 60 ⁇ / b> A includes a resonance resistor 61, a resonance coil 62, and a resonance capacitor 63.
  • the resistor 61, the resonance coil 62, and the resonance capacitor 63 are connected in parallel to each other. That is, the resonance circuit unit 60A shown in FIG. 7 is not a series resonance circuit like the resonance circuit unit 60 shown in FIG. 3, but a parallel resonance circuit.
  • the resonant coil 62 is an inductance L 2
  • the resonant capacitor 63 is the capacitance (electrostatic capacitance) C 2
  • the resonance frequency f of the resonance circuit section 60A shown in FIG. 7 2 can be expressed by the above-described equation (2), similarly to the resonance circuit unit 60 shown in FIG.
  • FIG. 8 is a circuit diagram for explaining still another example of the detected unit 50 shown in FIG. As shown in FIG. 7, the detected unit 50 includes a housing 51 and a resonance circuit unit 60 ⁇ / b> B housed in the housing 51.
  • the resonance circuit unit 60B includes a variable resistor 61B, a resonance coil 62, and a resonance capacitor 63.
  • the variable resistor 61B, the resonance coil 62, and the resonance capacitor 63 are connected to each other in series. That is, the resonance circuit unit 60B shown in FIG. 8 includes a variable resistor 61B instead of the resonance resistor 61 of the resonance circuit unit 60 shown in FIG.
  • the detection coil 21 and the oscillation capacitor 26 are caused by variations in the product of the element itself, variation due to mounting (assembly) of the sensor unit 10 in the case 11, and the like. , At least one of the inductance L1 and the capacitance C1 may change.
  • an error occurs in the resonance frequency of the LC oscillator circuit 20A, if the predetermined oscillation frequency f 0 of the oscillator circuit unit 20, is set to be equal to the resonance frequency of the inclusive LC oscillator resonant circuit 20A such errors, a given An error ⁇ ⁇ f 0 can occur in the oscillation frequency f 0 .
  • the resonance circuit 60 tries to set the resonance frequency f 2 based on the predetermined oscillation frequency f 0 and sets the resonance frequency f 2 to be the same as the resonance frequency f 1 calculated by the equation (1), Since there is an error ⁇ ⁇ f 0 at a predetermined oscillation frequency f 0 of the actual oscillation circuit unit 20, if the error ⁇ ⁇ f 0 is large, the Q value of the resonance circuit unit 60 is not sufficiently increased at the resonance frequency f 2 . There is a possibility that the proximity of the detection target A cannot be detected.
  • the resonance circuit section 60B shown in FIG. 8 includes a variable resistor 61B, when the error ⁇ Delta] f 0 of a predetermined oscillation frequency f 0 is large, a relatively large resistance R 2 of the variable resistor 61B by changing the value, as in the graph G 61 shown in FIG. 6, the Q value of the resonance circuit section 60B can be greater broadband frequency characteristics of the Q value in a wide frequency band, the resonant circuit The unit 60B can absorb the error ⁇ ⁇ f 0 of the predetermined oscillation frequency f 0 .
  • Q value of the resonance circuit portion 60B may be a large narrow banded frequency characteristics of Q values in a narrow frequency band, it is possible to have a large maximum value Q 62 in the vicinity of the resonance frequency f 2.
  • FIG. 9 is a circuit diagram for explaining still another example of the detected unit 50 shown in FIG. As shown in FIG. 7, the detected unit 50 includes a housing 51 and a resonance circuit unit 60 ⁇ / b> C housed in the housing 51.
  • the resonance circuit unit 60C includes a resonance resistor 61, a resonance coil 62, and a variable capacitor 63C.
  • the resonance resistor 61, the resonance coil 62, and the variable capacitor 63C are connected to each other in series. That is, the resonance circuit unit 60C shown in FIG. 9 includes a variable capacitor 63C instead of the resonance capacitor 63 of the resonance circuit unit 60 shown in FIG.
  • the resonance frequency f 2 that is the center line (center axis) can be shifted (moved). Therefore, when the error of the predetermined oscillation frequency f 0 is positive, the capacitance C 2 of the variable capacitor 63C is changed to a small value, thereby causing the graph G 61 and the graph G 62 to be positive (to the right in FIG. 6). If the error of the predetermined oscillation frequency f 0 is negative, the capacitance C 2 of the variable capacitor 63C is changed to a small value, so that the graph G 61 and the graph G 62 are in the negative direction (in FIG. 6). Shift to the left).
  • the detection circuit unit 30 determines the proximity of the detection target A based on the Q value of the oscillation circuit unit 20
  • the present invention is not limited thereto.
  • the sensor unit 10 comprises an oscillating circuit 20 for forming a magnetic field at a predetermined oscillation frequency f 0, based on a predetermined oscillation frequency f 0 of the sensor unit 10 comprising resonance circuit 60,60A having the resonance frequency f 2, 60B, and the detection unit 50 comprising the 60C, the.
  • the oscillation circuit unit 20 forms a magnetic field at the predetermined oscillation frequency f 0 and the resonance circuit units 60, 60A, 60B, and 60C have the resonance frequency f 2 based on the predetermined oscillation frequency f 0
  • the resonance circuit The parts 60, 60A, 60B, 60C resonate.
  • the resonant circuit units 60, 60A, 60B, and 60C that resonate, even when the change of the magnetic field (or magnetic flux of the magnetic field) is slight, a large voltage is generated as compared with the case where it does not resonate (non-resonant).
  • the power (energy) consumed by the resonance circuit units 60, 60 ⁇ / b> A, 60 ⁇ / b> B, and 60 ⁇ / b> C causes energy loss to the oscillation circuit unit 20. Therefore, when the sensor unit 10 and the detected object A are close to each other, when the change of the magnetic field (or the magnetic flux of the magnetic field) is slight (small), that is, the detection distance D between the sensor unit 10 and the detected object A is conventional.
  • the resonance circuit unit 60, 60A, 60B, 60C of the detected unit 50 provided in the detected object A gives energy loss to the oscillation circuit unit 20, and a predetermined value of the oscillation circuit unit 20, for example, Since the values of Q value, oscillation frequency, oscillation amplitude, internal resistance R 1 , inductance L 1 , impedance, etc. of the detection coil 21 change, the proximity of the detection target A can be detected.
  • the resonance circuit units 60, 60A, 60B, and 60C of the detected unit 50 provided in the detected object A give energy loss to the oscillation circuit unit 20 of the sensor unit 10, and the energy loss ,
  • the proximity of the detected object A is detected, so that even if the detected object A is a non-magnetic material, energy loss can be given to the oscillation circuit unit 20, and the detected object is a non-magnetic material. A can be detected. Further, due to the change of the magnetic field (magnetic flux of the magnetic field), not the detected object A itself, but the resonant circuit portions 60, 60A, 60B, 60C of the detected unit 50 provided in the detected object A give energy loss.
  • the detection distance D does not depend on the type of the detection target A (the detection distance D does not change depending on the type of the detection target A). Further, by using the resonance circuit portions 60, 60A, 60B, and 60C of the detected unit 50 provided on the detected object A, the electromagnetic induction action or the eddy current loss due to the electromagnetic induction action as in the conventional proximity sensor is used. Compared with the case where it does, the advantage (merit) that it is hard to receive to the influence of the magnitude
  • the detection distance can be increased without changing the size (size or dimension) of the sensor unit 10.
  • the resonance circuit units 60, 60A, 60B, and 60C include the resonance resistor 61 or the variable resistor 61B, the resonance coil 62, the resonance capacitor 63, or the variable. And a capacitor 63C.
  • the resonance circuit section 60, 60A, 60B, the resonance frequency f 2 of the 60C has the formula using the inductance L 2 of the resonant coil 62, and a capacitance C 2 of the resonance capacitor 63 or the variable capacitor 63C (2) It becomes possible to calculate by.
  • the resistance R 2 of the resonance resistor 61 or the variable resistor 61B does not affect the resonance frequency f 2 as shown in the equation (2), while the resonance resistor 61 or by varying the resistance R 2 of the variable resistor 61B, the resonance circuit section 60, 60A, 60B, it is possible to change the frequency characteristic of the Q value of 60C. Accordingly, embodiments using a resonant resistor 61 or resistor R 2 of the variable resistor 61B by setting (usage) together, without changing the resonance frequency f 2, the resonance circuit section 60, 60A, 60B, 60C The frequency characteristic of the Q value can be made a desired characteristic.
  • the resonance circuit unit 60B includes the variable resistor 61B.
  • the resistance R 2 of the variable resistor 61B is changed to a relatively large value, as shown in a graph G 61 shown in FIG.
  • the Q value of the resonance circuit unit 60B can have a wide frequency characteristic with a large Q value in a wide frequency band, and the resonance circuit unit 60B absorbs an error ⁇ ⁇ f 0 of a predetermined oscillation frequency f 0. Is possible.
  • the Q value of the resonance circuit unit 60B of the detected unit 50 can be increased, and the proximity of the detected object A can be detected.
  • the resistance R 2 of the variable resistor 61B is changed to a relatively small value, thereby resonating as shown in the graph G 62 shown in FIG.
  • Q value of the circuit section 60B may be a narrow-band of frequency characteristic Q value is large in a narrow frequency band, it is possible to have a large maximum value Q 62 in the vicinity of the resonance frequency f 2.
  • the Q value of the resonance circuit unit 60B of the detected unit 50 can be increased, and the Q value of the oscillation circuit unit 20 changes (decreases) greatly. ), The detection distance D can be further increased.
  • the resonance circuit unit 60C includes the variable capacitor 61C.
  • the capacitance C 2 of the variable capacitor 63C as shown in equation (2), so to change the resonance frequency f 2, by changing the capacitance C 2 of the variable capacitor 63C, the graph G 61 shown in FIG. 6 and in the graph G 62, thereby the resonance frequency f 2 is the central line (central axis) is shifted (moved). Therefore, when the error of the predetermined oscillation frequency f 0 is positive, the capacitance C 2 of the variable capacitor 63C is changed to a small value, thereby causing the graph G 61 and the graph G 62 to be positive (to the right in FIG. 6).
  • the capacitance C 2 of the variable capacitor 63C is changed to a small value, so that the graph G 61 and the graph G 62 are in the negative direction (in FIG. 6). Shift to the left). Therefore, when the error ⁇ Delta] f 0 and the actual predetermined oscillation frequency f 0 itself predetermined oscillation frequency f 0 is known, it can be to resonate the resonance circuit 60C, while maintaining the detection distance D, the detection object The proximity of A can be detected.
  • the detected unit 50 includes the nonmagnetic casing 51 that houses the resonance circuit units 60, 60A, 60B, and 60C. Accordingly, the magnetic flux generated by the oscillation circuit unit 20 can be applied to the resonance circuit units 60, 60A, 60B, and 60C, and the resonance circuit units 60, 60A, 60B, and 60C can be protected from the external environment. it can. Therefore, the detected unit 50 can improve environmental resistance performance such as water resistance, oil resistance, dirt resistance, vibration resistance, shock resistance, heat resistance, cold resistance, and the like, and the proximity sensor system 100 has environmental resistance. It can be suitably applied to the required use.
  • the oscillation circuit unit 20 includes the detection coil 21 and the oscillation capacitor 26.
  • the detection coil 21 when a current flows through the detection coil 21 at a predetermined oscillation frequency f 0 , the detection coil 21 generates a magnetic flux and forms a magnetic field (magnetic field) between the sensor unit 10 and the detection target A. .
  • the oscillation circuit unit 20 that forms a magnetic field at the predetermined oscillation frequency f 0 can be easily configured (realized).
  • the resonance frequency f 1 of the LC oscillation circuit 20A composed of the detection coil 21 and the oscillation capacitor 26 is expressed by the equation (1) using the inductance L 1 of the detection coil 21 and the capacitance C 1 of the oscillation capacitor 26. ). Accordingly, a predetermined oscillation frequency f 0 of the oscillator circuit unit 20 by setting the same as the resonance frequency f 1 which is calculated by the equation (1), it is possible to maximize the impedance of the LC oscillator circuit 20A, an oscillation circuit The power consumption of the unit 20 can be reduced.
  • the present invention can be applied to a technique for detecting the proximity (presence / absence) of an object to be detected.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Electronic Switches (AREA)
  • Switches That Are Operated By Magnetic Or Electric Fields (AREA)

Abstract

Le problème selon l'invention est de produire un système capteur de proximité ayant une distance de détection accrue sans en changer la taille. La solution de l'invention est un système capteur de proximité (100) qui détecte la proximité d'un objet à détecter (A) qui comporte : une unité de capteur (10) qui comporte une section de circuit d'oscillation qui forme un champ magnétique à une fréquence d'oscillation préétablie ; et une unité à détecter (50), laquelle est disposée dans l'objet à détecter (A) et comporte une section de circuit résonnant ayant une fréquence de résonance sur la base de la fréquence d'oscillation préétablie. La section de circuit d'oscillation est conçue en incluant une bobine de détection (21) et un circuit d'oscillation (25).
PCT/JP2014/051853 2013-03-25 2014-01-28 Système capteur de proximité WO2014156275A1 (fr)

Applications Claiming Priority (2)

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JP2013062346A JP2014187627A (ja) 2013-03-25 2013-03-25 近接センサシステム
JP2013-062346 2013-03-25

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WO2014156275A1 true WO2014156275A1 (fr) 2014-10-02

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111707868A (zh) * 2020-05-18 2020-09-25 华为技术有限公司 振荡电路的检测方法及装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6039727A (ja) * 1983-08-12 1985-03-01 沖電気工業株式会社 非接触接点信号伝達装置
JPH05315929A (ja) * 1992-05-12 1993-11-26 Seiko Instr Inc 物体近接検出装置
JP2011216256A (ja) * 2010-03-31 2011-10-27 Yamatake Corp 近接スイッチ

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6039727A (ja) * 1983-08-12 1985-03-01 沖電気工業株式会社 非接触接点信号伝達装置
JPH05315929A (ja) * 1992-05-12 1993-11-26 Seiko Instr Inc 物体近接検出装置
JP2011216256A (ja) * 2010-03-31 2011-10-27 Yamatake Corp 近接スイッチ

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111707868A (zh) * 2020-05-18 2020-09-25 华为技术有限公司 振荡电路的检测方法及装置

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