JP6692611B2 - Detector and measuring device - Google Patents

Description

  The present invention relates to a detection device that detects a physical quantity generated when a current flows through a conductor inserted through an insertion hole of a detection unit, and a measurement device including the detection device.

  As a detection device of this type, a device including a current detection unit and an attachment mechanism disclosed by the applicant in Patent Document 1 below is known. In this case, the current detection unit includes an annular magnetic core and a coil formed by winding a conductive wire around the magnetic core, and is configured in an annular shape having an insertion hole in the center. Further, the attachment mechanism includes a pair of cases, a conductor, and the like. Each case is configured to be fittable with each other, and accommodates the current detector in the fitted state. Further, in the central portion of each case, there is formed a cylindrical portion that is connected to each other in the fitted state of each case and that is inserted into the insertion hole of the current detection unit housed in each case. The conductor has a columnar shape and is inserted into a tubular portion of each case accommodating the current detecting portion to conduct the current to be measured.

  On the other hand, in this type of detection device, a shield is generally provided in order to suppress the influence of disturbance. In this case, for example, as a method of arranging the shield for suppressing the influence of the voltage of the same phase applied to the conductor on the current detection value, a method of winding an insulating sheet around the current detecting portion and winding a metal sheet as a shield on it is possible. Are known.

JP-A-2015-8194 (pages 5-6, FIG. 2)

  However, the conventional detection device having the shield arranged by the above method has the following problems to be improved. That is, in the current detection device provided with the shield by the method described above, since the distance between the current detection unit and the shield is short, a relatively large capacitance occurs between the two, when detecting a high frequency current, Due to this capacitance, it may be difficult to detect the current accurately, and improvement of this point is desired.

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide a detection device and a measurement device that can improve detection accuracy.

In order to achieve the above object, the detection device according to claim 1 has a detection part having an insertion hole in a central part, a conductor inserted in the insertion hole of the detection part, and the detection part and the conductor supported. A detection device for detecting a physical quantity generated when a current flows through the conductor, comprising a support part for shielding the detection part and a shield part for shielding the detection part, wherein the support part is formed of an insulator. A cylindrical first support body supporting the conductor inserted inside, a second support body formed of an insulator and arranged outside the first support body, and formed of an insulator. And a third support body that is disposed outside the second support body and supports the detection unit that is disposed outside the second support body in a state where the first support body is inserted into the insertion hole. The shield part is arranged around the support part. An outer peripheral shield that shields the detection unit, and a tubular shape that is disposed between the first support and the second support and that is supported by the second support to shield the conductor. An inner peripheral shield is provided, and the detection unit is supported by the third support in a state in which a gap is formed between the inner peripheral shield and the inner peripheral surface, and the inner peripheral shield and the detection unit. The space between the inner peripheral surface and the inner peripheral surface is maintained as a space .

The detecting device according to a second aspect is the detecting device according to the first aspect, wherein the inner peripheral surface of the detecting portion is separated from the outer peripheral surface of the second support.
Further, a detection device according to claim 3 is the detection device according to claim 1 or 2, wherein the first support, the second support, and the third support are integrally formed.
Further, the detection device according to claim 4 is the detection device according to any one of claims 1 to 3, wherein the third support is a bottom plate and is erected on the bottom plate and from the tip end side to the base end. An outer peripheral wall formed in a shape in which the thickness becomes thicker toward the portion side, and the outer peripheral portion of the detection unit disposed outside the second support is at an intermediate portion in the vertical direction of the outer peripheral wall. The detector is supported so as to contact the inner peripheral surface of the outer peripheral wall and restrict the movement of the detector with respect to the support.

Further, the detection device according to claim 5 is the detection device according to any one of claims 1 to 4 , wherein the second support is formed in a tubular shape separated from the first support, and the inner periphery is formed. The shield is supported by the second support body with a gap formed between the shield and the first support body.

According to a sixth aspect of the present invention, there is provided the detection device according to the fifth aspect , wherein the gap between the first support and the inner peripheral shield is maintained in a space state.

A measuring device according to a seventh aspect includes the detecting device according to any one of the first to sixth aspects, and a measuring unit that measures the current based on the physical quantity detected by the detecting device. .

According to the detection device according to claim 1 and the measurement device according to claim 7 , the detection device is arranged outside the second support in the support with the first support of the support inserted through the insertion hole. Since the detection unit is configured to be supported by the third support in a state where a gap is formed between the inner shield and the inner peripheral surface of the detection unit, the inner shield and the detection unit are sufficiently separated from each other. be able to. Therefore, according to the detection device and the measurement device, as compared with the conventional configuration in which the shield and the detection unit are close to each other, the capacitance between the inner peripheral shield and the inner peripheral surface of the detection unit is sufficiently large. Since it can be made small, the influence of the electrostatic capacitance at the time of detecting the high frequency current can be reduced, and the current detection accuracy can be sufficiently improved.

Further, according to the detection equipment Contact good beauty measurement apparatus, by the gap between the inner peripheral surface of the detecting portion and the inner peripheral shield is kept in the space, a gap of an insulating material such as resin filling The permittivity between the inner peripheral shield and the inner peripheral surface of the detection section can be reduced as compared with the configuration described above. Therefore, according to the detection device and the measurement device, it is possible to further reduce the capacitance between the inner peripheral shield and the inner peripheral surface of the detection unit, and as a result, the detection accuracy when detecting a high-frequency current is further improved. Can be improved.

Further, according to the detecting device of the fifth aspect and the measuring device of the seventh aspect , the inner peripheral shield disposed between the first support body and the second support body in the support portion is used as the first support body. By being configured to be supported by the second support in a state where a gap is formed between the conductor and the body, the conductor supported by the first support and the inner shield can be sufficiently separated from each other. Therefore, according to the detection device and the measurement device, it is possible to sufficiently reduce the electrostatic capacitance between the conductor and the inner circumference shield as compared with the conventional configuration in which the conductor and the shield are close to each other. Therefore, it is possible to reduce the influence of the electrostatic capacitance when detecting the high-frequency current and sufficiently improve the current detection accuracy.

Further, according to the detection device of the sixth aspect and the measurement device of the seventh aspect , since the gap between the first support and the inner peripheral shield is maintained in a space state, an insulator such as resin is formed. It is possible to reduce the dielectric constant between the conductor and the inner circumference shield as compared with the configuration in which the gap is filled with. Therefore, according to the detection device and the measurement device, it is possible to further reduce the electrostatic capacitance between the conductor and the inner peripheral shield, and as a result, it is possible to further improve the detection accuracy when detecting a high-frequency current. it can.

It is a perspective view showing a configuration of a current measuring device 100. 3 is a perspective view of the current measuring device 100 viewed from the bottom plate 11a side of the shield part 1. FIG. FIG. 3 is a perspective view of the current measuring device 100 with a part of the shield part 1 removed. 3 is an exploded perspective view of the current measuring device 100. FIG. FIG. 2 is a cross-sectional view of the X plane in FIG. It is a 1st explanatory view explaining the assembling method of the electric current measuring apparatus 100. It is a 2nd explanatory view explaining the assembling method of the current measuring device 100. It is a 3rd explanatory view explaining the assembling method of the current measuring device 100. It is a 4th explanatory view explaining the assembling method of current measuring device 100. It is a 5th explanatory view explaining the assembling method of current measuring device 100.

  Embodiments of a detection device and a measurement device will be described below with reference to the accompanying drawings.

  First, the configuration of the current measuring device 100 shown in FIGS. 1 and 2 as an example of the measuring device will be described. As shown in both figures and FIG. 3, the current measuring device 100 includes a shield part 1, a detecting part 2, a conductor 3, a supporting part 4 and a substrate 5, and is configured to be able to measure a current flowing through the conductor 3. There is. In this case, the detection device is configured by each component except the substrate 5. In FIG. 3, the second shield 12, which is a part of the shield part 1, is removed.

  As shown in FIG. 4, the shield part 1 is configured to include a first shield 11, a second shield 12, and a third shield 13.

  The first shield 11, for example, as shown in FIG. 4, is configured to include a rectangular bottom plate 11a and a rectangular side plate 11b provided upright on the bottom plate 11a. Further, the first shield 11 is, for example, manufactured by bending a conductive plate material (for example, a metal plate), and the bottom plate 11a and the side plate 11b are integrally formed.

  As shown in FIG. 4, for example, the second shield 12 is configured to include a rectangular top plate 12a and three rectangular side plates 12b to 12d that are vertically provided at the edges of the top plate 12a. The second shield 12 is, for example, manufactured by bending a conductive plate material (for example, a metal plate), and the top plate 12a and the side plates 12b to 12d are integrally formed.

  In this case, the first shield 11 and the second shield 12 correspond to the outer shield, and as shown in FIGS. 1 and 5, in the state where they are connected to each other, the detection unit 2, the conductor 3 (a part except a part), It is possible to cover the support part 4 (a part except a part) and the substrate 5. That is, the first shield 11 and the second shield 12 are arranged around the support part 4 supporting the detection part 2 in a state of being separated from the detection part 2.

  The third shield 13 corresponds to the inner circumference shield, and is formed in a cylindrical shape by a material having conductivity (for example, metal), as shown in FIG. In addition, as shown in FIG. 5, the third shield 13 is inserted into the insertion hole 21 a of the detection unit 2 in a state of surrounding the conductor 3 so that the third shield 13 and the first support 41, which will be described later, in the support unit 4. It is arranged between the second support 42. In this case, as shown in the figure, the third shield 13 is supported by arranging the outer peripheral surface 13a so as to contact the inner peripheral surface 42b of the second support body 42 (the outer peripheral wall 62 described later). Movement of the portion 4 in a direction along a plane orthogonal to the lengthwise direction of the first support 41 (hereinafter, movement in this direction is also referred to as “movement with respect to the support portion 4”) is restricted. Further, the third shield 13 is configured to be arranged in a state where a gap 51 is formed between the third shield 13 and the first support body 41. Specifically, the outer diameter of the third shield 13 is slightly smaller than the inner diameter of the second support 42, and the inner diameter is sufficiently larger than the outer diameter of the first support 41 (for example, the third support 13). It is formed to a diameter such that a gap 51 having the same width as the thickness of the shield 13 is formed.

  Further, the third shield 13 is fixed to the top plate 12a of the second shield 12 by fixing fittings 14 as shown in FIGS. In this case, the fixing metal fitting 14 is made of a conductive material. Therefore, the third shield 13 is electrically connected to the second shield 12 via the fixing fitting 14. Further, in the current measuring device 100, as shown in FIG. 5, the non-conductive support portion 4 is interposed between the first shield 11 and the third shield 13. Therefore, the current measuring device 100 has a structure in which a closed loop of current is not formed by the shield part 1 (the first shield 11, the second shield 12, and the third shield 13).

  The detection unit 2 is, for example, a through-type current transformer (CT) and includes an annular magnetic core and a coil (not shown) formed by winding a conductive wire around the magnetic core. 3 and 4, as shown in FIGS. 3 and 4, it has an annular shape (doughnut shape) in plan view having an insertion hole 21a in the center. Further, as shown in FIGS. 3 and 6, the detection unit 2 is arranged outside the second support body 42 of the support unit 4 with the first support body 41 of the support unit 4 inserted in the insertion hole 21a. And is supported by the third support 43 of the support portion 4.

  In this case, as shown in FIG. 5, in the detection unit 2, the outer peripheral portion 21c is in contact with the inner peripheral surface 43b of the third support body 43 (the outer peripheral wall 72 described later), and the inner peripheral surface 21b is the second support body. 42 (outer peripheral wall 62 described later) is disposed outside the second support body 42 so as to be sufficiently separated from the outer peripheral surface 42a, and is controlled by the third support body 43 in a state in which movement with respect to the support portion 4 is restricted. It is supported. That is, in the current measuring device 100, the outer diameter of the detection unit 2 is slightly smaller than the inner diameter of the third support body 43, and the inner diameter of the detection unit 2 is the outer diameter of the third shield 13 and the second support body 42. The support portion 4 is configured to have a diameter sufficiently larger than the outer diameter (for example, about twice the outer diameter of the third shield 13). The detection unit 2 also detects a magnetic field (physical quantity) generated when a current (AC current) flows through the conductor 3 inserted through the insertion hole 21a and outputs a detection signal (secondary current).

  The conductor 3 is made of a material having conductivity (for example, brass) and has a cylindrical shape as shown in FIG. Further, as shown in FIG. 5, screw holes 31a and 31b into which the screws 33a and 33b are screwed are formed in the base end portion 3a and the tip end portion 3b of the conductor 3. The conductor 3 is arranged inside the first support 41 in the support portion 4 and is supported by the first support 41.

  In this case, as shown in FIG. 5, the conductor 3 is arranged inside the first support body 41 so that the outer peripheral surface 3c abuts the inner peripheral surface 41b of the first support body 41. The movement with respect to the support portion 4 is restricted. Further, the conductor 3 is measured by a cable (or a bus bar) (not shown) that is connected to connecting fittings 32a, 32b that are connected to the base end portion 3a and the tip end portion 3b by screws 33a, 33b, respectively. Connected to the target power supply. With this configuration, the current output from the power supply to be measured (current to be detected) flows through the conductor 3.

  As shown in FIGS. 4 and 5, the support portion 4 is configured to include a first support body 41, a second support body 42, and a third support body 43. The support 4 is, for example, manufactured by injection molding using a resin (insulator) having an insulation property (non-conductivity), and the first support member 41, the second support member 42, and the third support member are manufactured. 43 is integrally formed.

  As shown in FIGS. 4 and 5, the first support 41 is formed in a cylindrical shape and supports the conductor 3 inserted (stored) inside. Further, as shown in FIG. 5, the first support body 41 is formed so that the outer peripheral surface 3 c of the conductor 3 abuts the inner peripheral surface 41 b when the conductor 3 is accommodated, so that the first support body 41 does not move with respect to the support portion 4. The conductor 3 can be supported in a regulated state. Specifically, the first support body 41 is formed so that the inner diameter thereof is slightly larger than the outer diameter of the conductor 3.

  As shown in FIG. 5, the second support body 42 is formed in a bottomed cylindrical shape having a bottom plate 61 and an outer peripheral wall 62 (see also FIG. 4), and the outer peripheral wall 62 is separated from the first support body 41. And is arranged outside the first support body 41. Further, as shown in FIG. 5, the base plate 41 (base end part 42 c) of the second support body 42 is connected (connected) to the base end part 41 c of the first support body 41. As shown in FIG. 5, when the third shield 13 is arranged between the second support 42 and the first support 41, the outer peripheral surface 13a of the third shield 13 becomes the inner peripheral surface 42b. The conductor 3 is supported, and the conductor 3 is supported in a state where the movement of the support 3 is restricted.

  As shown in FIG. 5, the third support body 43 is erected on the bottom plate 71 connected (connected) to the outer peripheral wall 62 of the second support body 42, and is erected on the bottom plate 71 and separated from the second support body 42. It is formed in a bottomed cylindrical shape (see also FIG. 4) having an outer peripheral wall 72 arranged outside the second support body 42. In this case, the outer peripheral wall 72 is formed in a tapered shape whose thickness increases from the tip end side toward the base end side (bottom plate 71 side). As shown in FIG. 5, in the third support 43, when the detection unit 2 is arranged outside the second support 42, the outer peripheral portion 21 c of the detection unit 2 extends in the vertical direction of the outer peripheral wall 72. The detection unit 2 is configured to be supported in a state where the detection unit 2 is in contact with the inner peripheral surface 43b of the outer peripheral wall 72 at the intermediate portion and thereby restricts movement with respect to the support unit 4. Specifically, the third support body 43 is formed such that the inner diameter of the outer peripheral wall 72 is slightly larger than the outer diameter of the detection unit 2. Further, the outer peripheral surface 43a of the outer peripheral wall 72 is provided with a plurality (three in this example) of fixing pedestals 43c for fixing the support portion 4 to the shield portion 1.

  The substrate 5 is attached to the bottom plate 11a of the first shield 11 as shown in FIG. The board 5 is configured by mounting electronic parts such as a CPU, and measures the current value of the current flowing through the conductor 3 based on the physical quantity (magnetic field) detected by the detection unit 2 (detection device). Function as a department.

  Next, an example of an assembling method of the current measuring device 100 will be described with reference to the drawings.

  First, as shown in FIG. 6, the detection unit 2 is arranged outside the second support body 42 in the support unit 4 (an annular region between the second support body 42 and the third support body 43). At this time, as shown in FIG. 5, the outer peripheral portion 21c of the detection unit 2 abuts on the inner peripheral surface 43b of the outer peripheral wall 72 of the third support body 43, so that the movement relative to the support unit 4 is restricted. The detection unit 2 is supported by the third support body 43. Further, in this state, as shown in the figure, a gap 52 is formed between the third shield 13 and the inner peripheral surface 21b of the detection unit 2. In this case, in the current measuring device 100, the gap 52 is maintained in a space state (a non-filling state in which the gap 52 is not filled with an insulator such as resin).

  Next, as shown in FIG. 7, the third shield 13 of the shield part 1 is arranged in the annular region of the support part 4 between the first support body 41 and the second support body 42. At this time, as shown in FIG. 5, the outer peripheral surface 13a of the third shield 13 abuts on the inner peripheral surface 42b of the second support body 42, whereby the third shield 13 causes the insertion hole 21a of the detection unit 2 to pass through. And is supported by the second support body 42 in a state in which the movement with respect to the support portion 4 is restricted. Further, in this state, as shown in the figure, a gap 51 is formed between the inner peripheral surface 13b of the third shield 13 and the outer peripheral surface 41a of the first support body 41. In this case, in the current measuring device 100, the gap 51 is maintained in a space state (a non-filled state in which the gap 51 is not filled with an insulator such as resin).

  Subsequently, as shown in FIG. 8, the conductor 3 is housed (inserted) inside the first support body 41 of the support portion 4. At this time, as shown in FIG. 5, the outer peripheral surface 3c of the conductor 3 abuts on the inner peripheral surface 41b of the first support body 41, whereby the conductor 3 is inserted into the insertion hole 21a of the detection unit 2. Thus, the first support body 41 supports the support portion 4 with its movement restricted.

  Next, as shown in FIG. 9, the substrate 5 is placed on the bottom plate 11a of the first shield 11, and the substrate 5 is fixed to the bottom plate 11a with the screws 15. Subsequently, as shown in the figure, the support portion 4 in a state of supporting the detection portion 2, the conductor 3, and the third shield 13 of the shield portion 1 is arranged on the substrate 5. At this time, the first support in the supporting portion 4 is inserted into the insertion hole 5a (see FIG. 4) formed in the substrate 5 and the insertion hole 11c (see FIG. 4) formed in the bottom plate 11a of the first shield 11. The base end portion 41c of the body 41 and the base end portion 42c of the second support body 42 are inserted and projected from the bottom plate 11a (see FIG. 2).

  Next, as shown in FIG. 9, the fixing pedestal 43c provided on the outer peripheral surface 43a of the fixing pedestal 43c of the third support body 43 is fixed to the substrate 5 and the bottom plate 11a using the screws 15. Subsequently, as shown in FIG. 5, the coupling fitting 32a is fixed to the base end portion 3a of the conductor 3 using the screw 33a.

  Next, as shown in FIG. 10, the second shield 12 is arranged on the first shield 11 so as to cover the support portion 4 (the detection portion 2 supported by the support portion 4) and the substrate 5. At this time, the tip end portion 41d of the first support body 41 and the tip end portion 13c of the third shield 13 in the support portion 4 are inserted into the insertion holes 12e formed in the top plate 12a of the second shield 12 so as to pass through the ceiling. It is projected from the plate 12a. Then, the first shield 11 and the second shield 12 are connected using the screw 15.

  Next, as shown in FIGS. 1 and 5, the fixing member 14 is fixed to the tip portion 13c of the third shield 13 with the screw 15. Subsequently, as shown in FIG. 1, the fixing member 14 is fixed to the top plate 12a of the second shield 12 with the screw 15. As a result, the second shield 12 and the third shield 13 are electrically connected via the fixing metal fitting 14.

  Next, as shown in FIG. 5, the connecting fitting 32b is fixed to the tip portion 3b of the conductor 3 by using the screw 33b. As described above, the assembly of the current measuring device 100 is completed.

  Next, a method of measuring the current value of the current to be measured using the current measuring device 100 will be described with reference to the drawings.

  When the current value of the current to be measured is measured using this current measuring device 100, first, the electric conductor 3 is connected to the connecting fittings 32a and 32b respectively connected to the base end portion 3a and the tip end portion 3b. Connect the cable (not shown) to the power supply to be measured (not shown). At this time, the current output from the power supply to be measured flows through the conductor 3. Further, the detection unit 2 detects a magnetic field (physical quantity) generated by a current flowing through the conductor 3 and outputs a detection signal (secondary current).

  In this case, in the current measuring device 100, since the detecting unit 2 is shielded by the shield unit 1, the influence of disturbance is sufficiently reduced, and as a result, the magnetic field corresponding to the current is accurately detected by the detecting unit 2. It is possible.

  Further, in the current measuring device 100, as shown in FIG. 5, the detection unit 2 is provided with a gap 52 formed between the third shield 13 forming the shield unit 1 and the inner peripheral surface 21b of the detection unit 2. Are arranged. That is, the third shield 13 and the inner peripheral surface 21b of the detection unit 2 are sufficiently separated from each other. Further, in the current measuring device 100, the gap 52 between the third shield 13 and the inner peripheral surface 21b of the detection unit 2 is maintained in a non-filled state (space state) in which an insulator such as resin is not filled. ing.

Here, assume a structure in which two conductors are arranged to face each other with an insulator interposed therebetween. In this case, assuming that the dielectric constant of the insulator is “ε”, the area of the conductor is “S”, and the distance between the conductors is “d”, the electrostatic capacitance C between the conductors is given by the following equation (1) ).
C = εS / d Equation (1)
From the above formula (1), it is understood that the capacitance C decreases as the distance d between the conductors increases, that is, the distance between the conductors increases. Further, from the equation (1), it is understood that the smaller the dielectric constant ε, the smaller the capacitance C.

  When the structure described above is applied to the current measuring device 100, the third shield 13 and the detecting unit 2 in the current measuring device 100 correspond to the conductors. Therefore, in the current measuring device 100 in which the third shield 13 and the inner peripheral surface 21b of the detection unit 2 are sufficiently separated from each other, the conventional metal sheet as a shield is wound on the insulating sheet wound around the detection unit. It is clear that the capacitance C between the third shield 13 and the detection unit 2 can be made sufficiently small as compared with the configuration, that is, the configuration in which the shield and the detection unit are close to each other. Further, in the current measuring device 100, as described above, the gap 52 between the third shield 13 and the inner peripheral surface 21b of the detection unit 2 is maintained in a space state. In this case, the dielectric constant ε of air is smaller than the dielectric constant ε of an insulator such as resin. Therefore, in the current measuring device 100, the permittivity ε between the third shield 13 and the detection unit 2 can be reduced as compared with the configuration in which the gap 52 is filled with an insulator such as resin. As a result, the capacitance C can be further reduced.

Further, when the inductance of the detection unit 2 is "L", the resonance frequency f _r of the capacitance C and the formed LC circuit between the inductance L, and a third shield 13 and the detector 2, the following It is represented by the equation (2).
_fr = 1 / √ (LC) ... Equation (2)
From the above equation (2), as the electrostatic capacitance C is small, the resonance frequency f _r increases, it is understood that high-frequency response is possible. Therefore, in the current measuring device 100 in which the electrostatic capacitance C between the third shield 13 and the detection unit 2 is sufficiently small, it is possible to sufficiently improve the detection accuracy when detecting a high frequency current. There is.

  In addition, in the current measuring device 100, as shown in FIG. 5, in the state where the gap 51 is formed between the third shield 13 forming the shield part 1 and the first support body 41 supporting the conductor 3. It is arranged. That is, the conductor 3 and the third shield 13 are sufficiently separated from each other. Further, in the current measuring device 100, the gap 51 between the third shield 13 and the first support body 41 is maintained in a non-filled state (space state) in which an insulator such as resin is not filled.

Here, it is assumed that a cylindrical second conductor is coaxially arranged with a cylindrical insulator sandwiched around the cylindrical first conductor (hereinafter, also referred to as “coaxial structure”). In this case, the dielectric constant of the insulator is “ε”, the inner diameter of the insulator (outer diameter of the first conductor) is “a”, and the outer diameter of the insulator (inner diameter of the second conductor) is “b”. And the length of the coaxial structure (the first conductor and the second conductor) is “l”, the electrostatic capacitance C between the first conductor and the second conductor is given by the following equation ( It is represented by 3).
C = 2πεl / ln (b / a) ... Equation (3)
From the above equation (3), the larger the ratio (difference between b and a) of the inner diameter b of the second conductor to the outer periphery a of the first conductor, that is, the first conductor and the second conductor are It is understood that the capacitance C decreases as the distance increases. Further, from the equation (3), it is understood that the smaller the dielectric constant ε, the smaller the capacitance C.

  When the above-mentioned coaxial structure is applied to the current measuring device 100, the conductor 3 in the current measuring device 100 corresponds to the first conductor, and the third shield 13 corresponds to the second conductor. Therefore, in the current measuring device 100 in which the conductor 3 and the third shield 13 are sufficiently separated from each other, for example, a configuration in which a metal sheet as a shield is wound around an insulating sheet wound around the outer peripheral surface of the conductor, That is, it is clear that the electrostatic capacitance C between the conductor 3 and the third shield 13 can be made sufficiently small as compared with the configuration in which the conductor and the shield are close to each other. Further, in the current measuring device 100, as described above, the gap 51 between the third shield 13 and the first support body 41 is maintained in a space state. In this case, the dielectric constant ε of air is smaller than the dielectric constant ε of an insulator such as resin. Therefore, in the current measuring device 100, the permittivity ε between the conductor 3 and the third shield 13 can be reduced as compared with the configuration in which the gap 51 is filled with an insulator such as resin. As a result, the capacitance C can be further reduced.

  In this case, the greater the capacitance C between the conductor 3 and the third shield 13, the lower the detection accuracy when detecting a high-frequency current, and the smaller the capacitance C, the higher the detection accuracy. Therefore, in the current measuring device 100 in which the electrostatic capacitance C between the conductor 3 and the third shield 13 is sufficiently small, the influence of the electrostatic capacitance C when detecting a high-frequency current is reduced, and the current It is possible to further improve the detection accuracy.

  On the other hand, the substrate 5 measures the value of the current to be measured based on the detection signal output from the detection unit 2 and outputs an electric signal indicating the measured value. Next, the electric signal output from the substrate 5 is sent to a display device (not shown), and the measured value of the current is displayed by the display device. The electric signal output from the substrate 5 is sent to a storage device (not shown), and the measured value of the current indicated by the electric signal is stored in the storage device.

  As described above, according to the detection device and the current measurement device 100, the detection device and the current measurement device 100 are arranged outside the second support body 42 in the support portion 4 with the first support body 41 of the support portion 4 inserted in the insertion hole 21a. Since the detection unit 2 is configured to be supported by the third support body 43 in the state where the gap 52 is formed between the third shield 13 and the inner peripheral surface 21b, the third shield 13 and the detection unit 2 are Can be sufficiently separated. Therefore, according to the detection device and the current measurement device 100, as compared with the conventional configuration in which the shield and the detection unit are close to each other, the static electricity between the third shield 13 and the inner peripheral surface 21b of the detection unit 2 is reduced. Since the capacitance C can be made sufficiently small, the influence of the capacitance C at the time of detecting the high frequency current can be reduced, and the current detection accuracy can be sufficiently improved.

  Further, according to the detection device and the current measurement device 100, since the gap 52 between the third shield 13 and the inner peripheral surface 21b of the detection unit 2 is maintained in a space state, the gap is made of an insulator such as resin. Compared with the configuration in which 52 is filled, the dielectric constant ε between the third shield 13 and the inner peripheral surface 21b of the detection unit 2 can be reduced. Therefore, according to the detection device and the current measurement device 100, the capacitance C between the third shield 13 and the inner peripheral surface 21b of the detection unit 2 can be further reduced, and as a result, the high frequency current is detected. In this case, it is possible to further improve the detection accuracy.

  Further, according to the detection device and the current measurement device 100, the third shield 13 disposed between the first support body 41 and the second support body 42 in the support portion 4 is connected to the first support body 41. Since the second support member 42 is configured to support the gap 51 between them, the conductor 3 and the third shield 13 supported by the first support member 41 can be sufficiently separated from each other. it can. Therefore, according to the detection device and the current measurement device 100, the electrostatic capacitance C between the conductor 3 and the third shield 13 is sufficient as compared with the conventional configuration in which the conductor and the shield are close to each other. Since it can be made extremely small, the influence of the electrostatic capacitance C at the time of detecting a high frequency current can be reduced, and the current detection accuracy can be further improved.

  Further, according to the detection device and the current measurement device 100, by maintaining the gap 51 between the first support body 41 and the third shield 13 in a space state, the gap 51 is filled with an insulator such as resin. The permittivity ε between the conductor 3 and the third shield 13 can be reduced as compared with the configuration described above. Therefore, according to the detection device and the current measurement device 100, the capacitance C between the conductor 3 and the third shield 13 can be further reduced, and as a result, the detection accuracy when detecting a high frequency current can be improved. It can be further improved.

  The configurations of the detection device and the measurement device are not limited to the above configurations. For example, the configuration example in which the gap 52 between the third shield 13 and the inner peripheral surface 21b of the detection unit 2 is maintained in a space has been described above, but a configuration in which the gap 52 is filled with an insulator such as resin is adopted. You can also

  Further, the configuration example in which the gap 51 between the first support body 41 and the third shield 13 is maintained in a space state has been described above, but a configuration in which the gap 51 is filled with an insulator such as resin may be adopted. .. Further, it is also possible to adopt a configuration in which the third shield 13 is supported in a state in which the gap 51 is not formed between the first support body 41 and the third shield 13. Specifically, the third shield 13 is configured such that the inner diameter of the third shield 13 is slightly larger than the outer diameter of the first support body 41, and the third shield 13 is provided on the outer circumference of the first support body 41. It is possible to adopt a configuration in which the third shield 13 is supported by the first support body 41 by fitting the. Further, when the third shield 13 is configured as described above, it is not necessary to support the third shield 13 by the outer peripheral wall 62 of the second support body 42, and therefore, the outer peripheral wall 62 having the bottom plate 61 that supports the third shield 13 is provided. It is also possible to employ the second support body 42 that does not have the wall 62.

  Moreover, although the support part 4 in which the first support body 41, the second support body 42, and the third support body 43 are integrally formed has been described as an example, the first support body 41 and the second support body separately formed. A supporting portion configured by connecting the body 42 and the third supporting body 43 can be adopted.

  Further, the outer peripheral portion 21c of the detecting portion 2 abuts on the inner peripheral surface 43b of the third supporting body 43 of the supporting portion 4, and the inner peripheral surface 21b of the detecting portion 2 contacts the outer peripheral surface 42a of the second supporting body 42 of the supporting portion 4. The example in which the detection unit 2 is disposed outside the second support body 42 so as to be spaced apart from the second support body 42 to support the detection unit 2 has been described above, but the outer peripheral portion 21c of the detection unit 2 is the inner periphery of the third support body 43. The detection unit 2 is arranged outside the second support body 42 so that the detection unit 2 is separated from the surface 43b and the inner peripheral surface 21b of the detection unit 2 is separated from the outer peripheral surface 42a of the second support body 42. You can also

  In this case, at least one between the outer peripheral portion 21c of the detection unit 2 and the inner peripheral surface 43b of the third support body 43 and between the inner peripheral surface 21b of the detection unit 2 and the outer peripheral surface 42a of the second support body 42. The detector 2 can be supported by filling the above with a filler (preferably a filler having a small dielectric constant). A configuration in which a filling material is filled between the inner peripheral surface 21b of the detection unit 2 and the outer peripheral surface 42a of the second support 42 to support the detection unit 2 (that is, to support the detection unit 2 In the configuration in which the outer peripheral wall 72 is not used), it is possible to employ the third support body 43 that has the bottom plate 71 that supports the detection unit 2 and does not have the outer peripheral wall 72.

  Further, a shield part having a different structure from the shield part 1 described above can be adopted. As an example, instead of the first shield 11, a configuration using a conductive pattern formed on the back surface of the substrate 5 can be adopted. Further, according to the specifications of the current measuring device 100, it is also possible to employ a shield portion that does not have one of the first shield 11 and the second shield 12.

  Further, the example applied to the current measurement device 100 that measures the current based on the physical quantity (magnetic field) detected by the detection device has been described above, but other than the current such as electric power and resistance based on the physical quantity detected by the detection device. It can be applied to various measuring devices for measuring the quantity to be measured.

DESCRIPTION OF SYMBOLS 1 shield part 2 detection part 3 conductor 4 support part 5 board | substrate 11 1st shield 12 2nd shield 13 3rd shield 21a insertion hole 21b inner peripheral surface 41 1st support body 42 2nd support body 43 3rd support body 51, 52 Gap 61,71 Bottom plate 62,72 Outer peripheral wall 100 Current measurement device

Claims (7)

A detection unit having an insertion hole in the central portion, a conductor inserted in the insertion hole of the detection unit, a support unit that supports the detection unit and the conductor, and a shield unit that shields the detection unit. A detection device for detecting a physical quantity produced when a current flows through the conductor,
The support part is formed of an insulator and has a cylindrical first support body that supports the conductor inserted therein. The support part is formed of an insulator and is disposed outside the first support body. A second support and an insulator, which is arranged outside the second support and is arranged outside the second support in a state where the first support is inserted into the insertion hole. And a third support that supports the detection unit,
The shield part is arranged between the first support body and the second support body, and the second support body is arranged around the support part and shields the detection part. And a cylindrical inner peripheral shield that shields the conductor by being supported by
The detection unit is supported by the third support in a state where a gap is formed between the inner peripheral shield and the inner peripheral surface ,
A detection device in which the gap between the inner shield and the inner surface of the detection unit is maintained in a space state . The detection device according to claim 1, wherein the inner peripheral surface of the detection unit is configured to be separated from the outer peripheral surface of the second support body. The detection device according to claim 1, wherein the first support, the second support, and the third support are integrally formed. The third support includes a bottom plate and an outer peripheral wall that is provided upright on the bottom plate and has a thickness that increases from the tip end side toward the base end side. The detection is performed in a state in which the outer peripheral portion of the detection portion disposed on the outside abuts the inner peripheral surface of the outer peripheral wall at an intermediate portion in the vertical direction of the outer peripheral wall to restrict movement of the detection portion with respect to the support portion. The detection device according to any one of claims 1 to 3, which is configured to be able to support the portion. The second support is formed in a tubular shape separated from the first support,
The detection device according to claim 1, wherein the inner peripheral shield is supported by the second support in a state where a gap is formed between the inner shield and the first support. The detection device according to claim 5 , wherein the gap between the first support and the inner shield is maintained in a space state. A detection device according to any one of claims 1 to 6, in which the measurement apparatus and a measurement unit for the current measured on the basis of the physical amount detected by the detection device.

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