JP2013044705A - Current detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small current detection device which can be easily assembled with a small number of constituent components without using a magnetic core.SOLUTION: A measurement object current conductor 2 in which the measurement object current flows in its longitudinal direction has at least an almost strip shaped part having a prescribed thickness. A cut out 4 is formed to at least one of two long sides of the measurement object current conductor 2. A printed wiring board 1 on which a magnetic sensor 3 is mounted is fixed to the measurement object current conductor 2 so that the magnetic sensor 3 is arranged at the cut out 4.

Description

  The present invention relates to a current detection device. More particularly, the present invention relates to a current detection device that includes a current conductor to be measured and a magnetic sensor and does not use a magnetic core and is intended to detect a large current.

  As shown in Patent Document 1, a well-known current detection device has a magnetic core disposed around a current conductor to be measured and a magnetic sensor disposed in a gap provided in the magnetic core. A magnetic field generated from a measurement current is collected by a magnetic core and detected by a magnetic sensor. However, since such a conventional current detection device needs to prevent magnetic saturation of the magnetic core, the magnetic core must be enlarged as the amount of current to be measured increases. If the value is large, there is a problem that the current detection device also becomes large.

  In order to solve such a problem, a coreless current detection device (Patent Document 2) that does not use a magnetic core has been recently proposed.

JP 2002-243768 A JP 2002-243766 A

  However, if the magnetic core is not used, it is susceptible to disturbance magnetic field noise, so a magnetic sensor is mounted on a substrate that surrounds the current conductor to be measured, and the magnetic sensor is placed on both sides of the current conductor to be measured. There is a problem in that it is necessary to cancel the influence of disturbance magnetic field noise, resulting in a large current detection unit.

  Further, when the magnetic core is not used, the magnetic field detected by the magnetic sensor is inversely proportional to the distance from the current conductor to be measured, and therefore it is necessary to dispose the magnetic sensor with high accuracy with respect to the current conductor to be measured.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a very small current detection device in which a magnetic sensor can be arranged with high accuracy and can be easily assembled. is there.

  The present invention devised to solve the above problems is a conductor having at least a substantially strip-shaped portion having a predetermined thickness, and a current conductor to be measured through which a current to be measured flows, and A current detecting device including a magnetic sensor for detecting a magnetic field generated by the current to be measured, wherein the notch is disposed on at least one of the two long sides of the substantially strip shape, Provided is a current detection device including a notch in which the magnetic sensor is disposed. The current detection device preferably includes a through hole penetrating the predetermined thickness on both sides in the vicinity of the notch.

  Here, the notch portions may be arranged in at least a pair of positions symmetrical with respect to a center line of the substantially strip shape parallel to the longitudinal direction on both of the two long sides, or Further, both of the two long sides may be arranged at least at a pair of positions that are not symmetric with respect to the substantially strip-shaped center line parallel to the longitudinal direction as an axis of symmetry.

  Further, here, the notch portion has a rectangular shape that cuts the substantially strip shape, and the depths of the pair of notch portions disposed at the at least one pair of positions are equal, and The through hole can be positioned on the center line. Alternatively, the cutout portion has a rectangular shape that cuts the substantially strip shape, the depths of the cutout portions that are disposed at the at least one pair of positions are made different from each other, and the through holes are formed. In addition, it can be positioned on a line that passes through the center position of the pair of notches and is parallel to the longitudinal direction.

  Alternatively, the notch may be disposed on one of the two long sides.

  In addition, both the shape in which the cutout portion cuts out the substantially strip shape and the shape in which the through hole penetrates the substantially strip shape are rectangular, the depth of the cutout portion in the short direction and the depth of the cutout portion. The sum of the widths of the through holes in the short direction can be made larger than the width of the substantially strip-shaped portion.

  Furthermore, the printed circuit board can be further provided with a printed circuit board fixed to the conductor to be measured, on which the magnetic sensor disposed in the notch portion is mounted. It may be fixed to the conductor to be measured.

  As described above, according to the present invention, a conductor having at least a substantially strip-shaped portion having a predetermined thickness and having two long sides of a current conductor to be measured through which a current to be measured flows in the longitudinal direction thereof. At least one notch is provided, and the printed circuit board on which the magnetic sensor is mounted is fixed to the current conductor to be measured so that the magnetic sensor is located at the notch, thereby accurately arranging the magnetic sensor. An extremely small current detection device that can be easily assembled can be provided. Moreover, the magnetic field of a magnetic sensor part can be strengthened by providing a notch part and a through-hole in a to-be-measured current conductor, and the effect that current detection sensitivity can be improved is also acquired.

1 is a perspective view showing an embodiment of a current detection device according to the present invention. It is a figure explaining the electric current which flows through the to-be-measured current conductor in FIG. It is a perspective view which shows another embodiment of the electric current detection apparatus which concerns on this invention. It is a figure explaining the electric current which flows through the to-be-measured current conductor in FIG. It is a perspective view which shows the modification using the screw for fixation of the electric current detection apparatus which concerns on this invention. It is a perspective view which shows the modification using the insulator of the electric current detection apparatus which concerns on this invention. It is a figure explaining the relationship between a notch depth, a through-hole width | variety, and a conductor width in the electric current detection apparatus which concerns on this invention. It is a figure explaining the position of the width direction according to the notch depth in which a through-hole is located in a conductor in the electric current detection apparatus which concerns on this invention. It is a figure which shows the modification about the arrangement | positioning of a notch and a magnetic sensor of the electric current detection apparatus which concerns on this invention.

  Hereinafter, the current detection mechanism of the present invention will be described with reference to the drawings.

  FIG. 1 shows an embodiment of a current detection device according to the present invention. As shown in FIG. 3A, the current detection device includes a printed wiring board 1 on which two magnetic sensors 3 are mounted and a substantially strip-shaped current conductor 2 having a predetermined thickness. It is comprised by fixing using the adhesive agent so that the magnetic sensor 3 may be arrange | positioned at the two notch parts 4 provided in both. The adhesive must be insulative, and for example, an epoxy resin type is preferable. FIG. 2B shows the current detection device after assembly. The direction in which the current to be measured flows in FIG. 4B is the long side direction of the substantially strip shape, that is, the long side direction of the current conductor 2 to be measured, and is orthogonal to the long side direction and in the surface direction of the substantially strip shape. The parallel direction (thickness direction) is the short side direction.

  As shown in FIG. 1, since it can be configured only by combining the current conductor 2 to be measured provided with the notch 4 and the printed wiring board 1 on which the magnetic sensor 3 is mounted, a very small current detection device can be easily assembled. I understand.

  In order to improve the detection accuracy by arranging the magnetic sensor 3 with high accuracy, the size of the cutout portion 4 of the current conductor 2 to be measured is 0.5 mm to 2.0 mm larger than the package of the magnetic sensor 3 including the terminals. The width in the short side direction of the printed wiring board 1 and the width in the short side direction of the current conductor 2 to be measured are desirably substantially the same.

  FIG. 2 is a diagram for explaining the effect of the notch 4 acting on the current flowing through the current conductor 2 to be measured in the embodiment shown in FIG.

  Since the width of the current path is narrow at the portion where the notch portion 4 is provided, as shown by the current path to be measured 5, the portion to be covered passes through the vicinity of the edge of the notch portion 4 where the magnetic sensor 3 is disposed. Since the measurement current flows and the current density at the part is increased, the magnetic flux density at the position of the magnetic sensor 3 is increased, and thereby the detection sensitivity of the magnetic sensor 3 can be increased.

  The notch 4 may be provided only on one of the two long sides of the strip-shaped current conductor 2 (see FIG. 8A), but as in the embodiment shown in FIG. It is preferable that the two notches 4 are provided on both long sides of the current conductor 2 to be measured because the current flows more concentratedly. Further, two notches 4 are provided at symmetrical positions on both long sides of the current conductor 2 to be measured, and two magnetic sensors 3 are arranged in the notches 4 so that the outputs of the two magnetic sensors 3 can be obtained. It is preferable to obtain the effect of canceling the influence of the disturbance magnetic field by taking the signal difference.

  Further, in the present embodiment, the two notches 4 are arranged so that the notches 4 are located symmetrically on both sides of the short-side end of the current conductor 2 to be measured, and the notches 4 Although the depths of the notches 4 may be asymmetrical as shown in FIGS. 8B and 8C, which will be described later, FIG. 7B and FIG. The arrangement position of the notch 4 may be asymmetrical as shown in 7 (c). When the magnetic sensors 3 are arranged on the left and right long sides of the current conductor 2 to be measured, the two magnetic sensors 3 arranged in the notches 4 are made the same by making the notches 4 have the same depth. Are preferable because the current sensitivity becomes equal.

  FIG. 3 shows an embodiment of a current detection device in which a through-hole 6 is provided in the current conductor 2 to be measured. The direction in which the through hole 6 penetrates the current conductor 2 to be measured is the same direction as the thickness direction of the current conductor 2 to be measured, that is, the direction perpendicular to the strip surface direction of the strip.

  FIG. 4 shows the current flowing through the current conductor 2 to be measured in the embodiment shown in FIG. Since the through hole 6 is provided at the center in the short side direction with the notch 4 of the current conductor 2 to be measured interposed therebetween, the current to be measured is at the edge of the notch 4 as shown by the current path 5 to be measured. The effect of increasing the detection sensitivity of the magnetic sensor 3 can be obtained as compared with the case of the current conductor 2 to be measured without the through hole 6 (see FIG. 2).

  As shown in FIG. 3 and FIG. 4, it is preferable that there are two through holes 6 in the vicinity of the notch 4 so as to sandwich the region where the notch 4 is provided. Furthermore, it is more preferable that the through hole 6 is arranged at a symmetrical position with respect to the region where the notch 4 is provided.

  The arrangement of the through-hole 6 will be described in more detail. The through-hole 6 is like a hatched portion indicated by La, Lb, Lc1, and Lc2 in FIGS. In addition, it is preferable to provide a region other than the region where the conductor width is narrowed by the notch 4 and in the vicinity of the notch 4. This is because current can flow in the vicinity of the edge of the notch 4 where the magnetic sensor 3 is disposed, and the current sensitivity of the magnetic sensor 3 can be increased.

  As the shape of the notch 4 and the through-hole 6, for example, a substantially rectangular shape can be used. The width of the through hole 6 is the sum of the length of the notch 4 in the short side direction of the current conductor 2 to be measured and the length of the through hole 6 in the short side direction of the current conductor 2 to be measured. It is preferably larger than the length of the short side of 2. Specifically, for example, as shown in FIGS. 7A to 7C, the sum of the width d of the through hole 6 and the length 2A of two notches 4 is the current conductor 2 to be measured. Is preferably larger than the length D in the short side direction. Thereby, an electric current can be sent to the vicinity of the edge of the notch part 4 where the magnetic sensor 3 is arrange | positioned more efficiently.

  When the notch depth of the notch 4 is symmetrical, the through hole 6 is preferably provided at a position on the center line of the current conductor 2 to be measured parallel to the longitudinal direction of the current conductor 2 to be measured. This is because the current flowing through the measured current path can flow in the vicinity of the edge of the notch 4. (See FIG. 4).

  In addition, when the notch depth of the notch 4 is asymmetrical or when the notch 4 is one, the center of the current path to be measured may not coincide with the center of the current conductor 2 in the width direction. To do. Even in such a case, the through hole 6 is parallel to the longitudinal direction of the measured current conductor 2 and passes through the center in the width direction of the measured current conductor 2 in the region where the conductor width is narrowed by the notch 4. It is preferably provided at a position on the center line of the current conductor 2 to be measured. This is preferable because the current flowing through the measured current path can flow in the vicinity of the edge of the notch 4.

  FIG. 5 shows a modification of the embodiment shown in FIG. The modification is an example of a current detection device that fixes the current conductor 2 to be measured and the printed wiring board 1 with screws 7. The through hole 6 provided in the current conductor 2 to be measured is also used as a through hole for coupling the male screw 7a with the female screw 7b. In this case, a through hole (not shown) is opened at the same position in the printed wiring board 1 and the male screw 7a is inserted.

  FIG. 6 shows another modification of the embodiment shown in FIG. In this modification, the printed wiring board 1 and the measured current conductor 2 are fixed by sandwiching the sheet-like insulator 8 between the printed wiring board 1 and the measured current conductor 2. This is an example of a current detection device in which insulation of the current conductor 2 is ensured. As the insulator, various materials such as PBT, ABS, Duracon, polyester, PPO, polyamide, PPS, nylon 66 can be applied, but it is preferable to use a material having excellent flame resistance and tracking resistance. desirable.

  As a modification of the arrangement of the notch and the magnetic sensor, the magnetic sensor 3 can be provided with a plurality of pairs on the long side of the current conductor 2 to be measured. FIG. 9A shows a configuration in which two pairs of symmetrical notches are arranged, and the magnetic sensor 3 is arranged in each of the notches, and FIG. 9B shows two symmetrical pairs of notches. 1 shows a configuration in which two magnetic sensors 3 are arranged in each notch. Furthermore, another pair of magnetic sensors 3 may be arranged, or another pair of notches may be arranged.

DESCRIPTION OF SYMBOLS 1 Printed wiring board 2 Current conductor to be measured 3 Magnetic sensor 4 Notch part 5 Current path to be measured 6 Through hole 7a, 7b Fixing tool (screw)
8 Insulator

Claims (10)

A conductor having at least a substantially strip-shaped portion having a predetermined thickness, a measured current conductor through which a measured current flows in the longitudinal direction thereof, and a magnetic sensor for detecting a magnetic field generated by the measured current A current detection device comprising:
A current detection device comprising: a notch portion disposed on at least one of the two long sides of the substantially strip shape, wherein the notch portion is provided with the magnetic sensor.   The current detection device according to claim 1, wherein a through hole penetrating the predetermined thickness is provided on both sides in the vicinity of the notch.   3. The cutout portion is disposed at at least a pair of positions symmetrical about a center line of the substantially strip shape parallel to the longitudinal direction on both of the two long sides as a symmetry axis. The current detection device described in 1.   3. The cutout portion is disposed in at least a pair of positions that are not symmetrical with respect to a center line of the substantially strip shape parallel to the longitudinal direction on both of the two long sides as a symmetry axis. The current detection device described in 1. The shape in which the notch cuts out the substantially strip shape is a rectangle,
The at least one pair of positions, the notch portions forming a pair have the same depth, and
The current detection device according to claim 3, wherein the through hole is located on the center line. The shape in which the notch cuts out the substantially strip shape is a rectangle,
The depths of the notch portions forming a pair disposed at the at least one pair of positions are different, and
5. The current detection device according to claim 3, wherein the through hole is located on a line passing through a center position between the pair of cutout portions and parallel to the longitudinal direction.   The current detection device according to claim 2, wherein the notch is disposed on one of the two long sides. Both the shape in which the cutout portion cuts out the substantially strip shape and the shape in which the through hole penetrates the substantially strip shape are rectangular,
The sum of the depth in the lateral direction of the substantially rectangular shape of the notch and the width in the lateral direction of the through hole is larger than the width of the substantially rectangular portion. The current detection device described.   9. The printed circuit board fixed to the conductor to be measured, further comprising a printed circuit board on which the magnetic sensor disposed in the notch is mounted. The current detection device described.   The current detection device according to claim 9, wherein the printed circuit board is fixed to the conductor to be measured via an insulator.

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