JP2010223929A - Magnetic core and current sensor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: a magnetic core for a current sensor which is easily processed and assembled, which can be miniaturized, which can be reduced in cost because it can be made of a rectangular magnetic material of the same dimensions without waste loss, and which can adjust a range of currents to be measured; and a current sensor using the same. <P>SOLUTION: The magnetic core is structured such that a magnetic circuit is formed by at least one plate-like magnetic material and a gap part formed by a void provided between ends of the magnetic material by bending the magnetic material substantially circularly. The ends of the magnetic material form the gap part by facing each other at a predetermined distance from each other with predetermined areas, and at least one of the ends faces a convexly-processed surface. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a magnetic core that forms part of a magnetic circuit used to measure a current to be measured flowing through a conductor, and a current sensor that includes the magnetic core.

  The magnetic core used for measuring the current to be measured is installed so as to surround the conductor through which the current to be measured flows, and forms a magnetic circuit together with the gap portion provided in the magnetic core. The current sensor using the magnetic core measures the magnitude of the current to be measured in a non-contact manner by measuring the magnitude of the magnetic flux generated in the magnetic circuit by the current to be measured through the magnetoelectric transducer installed in the gap portion. .

  As an example of a magnetic core constituting a conventional current sensor, there is a magnetic core in which one or a plurality of plate-like magnetic materials are subjected to some processing such as bending, and a magnetic circuit is formed with a gap portion. (For example, see Patent Documents 1, 2, or 3)

JP 2000-284000 JP2006-17457 JP2008-233303

  The magnetic core of the current detection device disclosed in Patent Document 1 is formed by connecting two U-shaped magnetic materials produced by bending a plate material, and a magnetic material such as ferrite is used. There is an advantage that it is thinner than a magnetic core formed by sintering. In another embodiment, there is shown a magnetic core constructed by connecting two other U-shaped magnetic materials whose peripheral portions are bent, which has the advantage of improving the magnetic flux collection effect. However, since the magnetic core structure is difficult to process from one plate material, and it is necessary to connect at least two magnetic materials, there is a problem that the assembly process increases. In addition, since a U-shaped magnetic material is required, there is a problem that an unnecessary plate material part is always generated when considering material removal from the base material, which is not suitable for cost reduction. . Furthermore, in order to improve the magnetic flux collection effect, it is necessary to prepare another U-shaped magnetic material with an enlarged peripheral edge, so multiple types are required to satisfy multiple specifications such as current sensor ratings. It is essential to have a plate-like magnetic material, and there is a problem that it is not suitable for cost reduction such as an increase in storage space.

  The magnetic core of the current sensor unit disclosed in Patent Document 2 is formed by bending a single rectangular plate-shaped magnetic material, and is formed by sintering a magnetic material such as ferrite. Compared with this, there is an advantage that the processing is easy and the size is reduced. In another embodiment, there is shown a magnetic core formed by adjusting the gap interval and overlapping area, dividing the magnetic core, or adding a magnetic material, and adjusting the magnitude of the magnetic flux in the gap, that is, There is an effect that the current range to be measured can be adjusted. However, it is difficult to realize various magnetic cores shown in Patent Document 2 from a single plate-shaped magnetic material having the same dimensions, in order to satisfy a plurality of specifications such as current sensor ratings. However, it is necessary to have multiple types of plate-like magnetic materials, and there is a problem that it is not suitable for cost reduction such as an increase in storage space.

  The magnetic core for a current sensor disclosed in Patent Document 3 is formed by bending a single plate-like magnetic material, and compared with a magnetic core formed by sintering a magnetic material such as ferrite. There is an advantage that processing becomes easy. In addition, since the magnetic core is formed by processing the magnetic material so that the width of the magnetic material is inclined toward the end of the magnetic material forming the gap portion of the magnetic core, the adjustment of the magnitude of the magnetic flux in the gap portion, that is, Has the effect of adjusting the measured current range. However, since a magnetic material with an inclined width is required, there is a problem that an unnecessary plate material part is generated and it is not suitable for cost reduction in consideration of material removal from the base material. there were. Also, in order to satisfy multiple specifications such as current sensor ratings, it is essential to have multiple types of plate-like magnetic materials with variable width and inclination of the magnetic material, which reduces the cost of storage, etc. There was a problem that it was not suitable. Furthermore, since the magnetic core having an inclined structure is not suitable for thinning, there is a problem that the volume is increased in configuring the current sensor.

  The present invention has been made in order to solve the above-mentioned problems, and is easy to process and assemble, can be downsized, and can use a rectangular plate-like magnetic material having the same dimensions without waste loss. It is an object of the present invention to provide a magnetic core for a current sensor and a current sensor using the same.

  A magnetic core according to the present invention includes a magnetic circuit including at least one plate-like magnetic material and a gap portion formed by bending the magnetic material into a substantially annular shape and a gap provided between end portions of the magnetic material. The both ends of the magnetic material are opposed to each other with a predetermined distance and a predetermined area to form a gap portion, and at least one of the opposing surfaces of the end portion is processed into a convex shape. ing.

  In the magnetic core according to the present invention, both end portions of the magnetic material are opposed to each other with a predetermined distance and a predetermined area to form a gap portion, and at least one flat surface of at least one end portion is flat. It may be processed into a convex shape having a portion.

  In the magnetic core according to the present invention, both end portions of the magnetic material are opposed to each other with a predetermined distance and a predetermined area to form a gap portion, and at least one end surface of the magnetic material is processed into a concave shape. It may be.

  In the magnetic core according to the present invention, both end portions of the magnetic material are opposed to each other with a predetermined distance and a predetermined area to form a gap portion, and at least one flat surface of at least one end portion is flat. You may be processed into the concave shape which has a part.

  The current sensor according to the present invention includes any one of the magnetic cores, at least one magnetoelectric conversion element installed in the gap portion, and a sensor circuit unit connected to the magnetoelectric conversion element. A sensor substrate on which the element is held at a predetermined position of the gap portion and the sensor circuit portion is installed is fixed to the magnetic core.

According to the magnetic core of the present invention, the magnetic core is formed by bending a plate material, which is a single magnetic material, into a substantially annular shape, and forming a gap portion between the end portions of the magnetic material. There is also an effect of miniaturization.
In addition, according to the magnetic core of the present invention, the shape of the end of at least one magnetic material is convex, concave, or at least one flat portion without changing the original dimensions of the plate material that is one magnetic material. Can be easily adjusted to the current range to be measured, the original magnetic material can be shared for multiple specifications, and multiple dimensions of magnetism can be achieved. Since there is no need to possess materials, there is also an effect of cost reduction.
In addition, according to the magnetic core of the present invention, since the original shape of the plate material, which is a single magnetic material, is a rectangle, there is no unnecessary part in removing material from the base material plate, reducing waste loss. As a result, the cost can be reduced.

  Also, according to the current sensor of the present invention, a small current sensor can be provided because of the structure in which the sensor substrate provided with the magnetoelectric conversion element and the sensor circuit is fixed to the magnetic core.

It is a perspective view of the magnetic core by Embodiment 1 of this invention. It is a top view of the magnetic core by Embodiment 1 of this invention. It is sectional drawing of a part of magnetic core by Embodiment 1 of this invention. It is a structure schematic diagram of a general current sensor. It is a sectional view of a part of a conventional magnetic core. It is sectional drawing of a part of another magnetic core by Embodiment 1 of this invention. It is a relationship figure of to-be-measured current value-Hall voltage in the some magnetic core by Embodiment 1 of this invention. It is another sectional drawing of a part of magnetic core by Embodiment 1 of this invention. It is a relationship figure of measured current value-Hall voltage in a plurality of Hall elements by Embodiment 1 of this invention. It is a relationship figure of to-be-measured current value after correction | amendment-Hall voltage in the some Hall element by Embodiment 1 of this invention. It is a perspective view of the current sensor by Embodiment 2 of this invention.

Embodiment 1 FIG.
FIG. 1 is a perspective view of a magnetic core according to Embodiment 1 of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a cross section showing an AA ′ section (YZ plane) in FIGS. It is a figure (a sectional view of a part of magnetic core 1). In the figure, a magnetic core 1 is formed by bending a substantially rectangular plate-shaped magnetic material 2 into a substantially annular shape to form a gap 3 between an inner end 4 and an outer end 5 of the magnetic material 2. The magnetic core 1 is configured to have a hollow portion 6 inside. In the magnetic core 1, a magnetic circuit is constituted by the magnetic material 2 and the gap portion 3. Here, in particular, the inner end portion 4 is processed into a convex shape having a flat portion 7 toward the outer end portion 5.
In order to configure as a current sensor, a conductor through which the current to be measured flows at least in the hollow portion 6 of the magnetic core 1 and a magnetoelectric conversion element are installed at a predetermined position in the gap portion 3. Details of the configuration as a current sensor Will be described in Embodiment 2.

First, a method for manufacturing the magnetic core 1 will be described.
The magnetic material 2 constituting the main configuration of the magnetic core 1 uses a soft magnetic material having a high magnetic permeability, and for example, silicon steel or permalloy is used. The magnetic material 2 is prepared as a rectangular plate before being processed into the magnetic core 1, and is produced by cutting out from a plate as a base material such as silicon steel. Since the magnetic material 2 is cut into a rectangular strip from the base material, basically no waste material is generated and the design is environmentally friendly.
The magnetic material 2 which is a rectangular plate material is first processed at the end. In the present embodiment, only the inner end 4 that will be positioned on the hollow portion 6 side of the magnetic core 1 is processed, but the present invention is not limited to the inner end. The inner end portion 4 is formed in a convex shape by pressing or the like so as to protrude downward toward the outer end portion 5, that is, in the YZ section of FIG. Although the convex shape having the flat portion 7 is used here, the shape of the convex portion, such as the presence / absence, size, etc. of the flat portion 7, is used for constructing a current sensor having a target rating and a target current range to be measured. Thus, it is adjusted according to the magnitude of the magnetic flux to be applied to the magnetoelectric conversion element installed in the gap portion 3. In addition, in the longitudinal direction of the magnetic material 2, the range in which the convex shape is formed is up to the refracting portion 8 of the magnetic material 2 closest to the inner end portion 4, and the convex shape portion and the refracting portion 8 are crossed, etc. A machining shape having an extreme edge is desirably avoided because it affects the magnetic circuit.
Next, the magnetic material 2 is bent into a substantially annular shape to form the magnetic core 1. At that time, the distance between the inner end 4 and the outer end 5 forming the gap 3 is a distance at which a magnetic flux to be applied to the magnetoelectric conversion element installed in the gap 3 is obtained, and at least later, the magnetoelectric conversion element is stable. Set to a distance that can be installed in. However, when the target rating and the current range to be measured are different, the required magnetic field is adjusted first by the convex shape of the inner end 4, and then if necessary, the inner end 4 and the outer It shall be performed with the space | interval of the edge part 5. FIG. By such adjustment, the rectangular magnetic material 2 having a certain length can be adapted to a plurality of specifications such as a plurality of ratings or a current range to be measured without greatly changing the external dimensions of the magnetic core 1. In addition, since the external dimension of the magnetic core 1 does not change greatly, the overlapping area of the inner end portion 4 and the outer end portion 5 is substantially constant when viewed from the Y direction. As can be seen from FIG. 1 or FIG. 2, in the present embodiment, the four refracting portions 8 formed when bending in a substantially annular shape are substantially perpendicular, but this is not restrictive. It does not matter in the form. The shape of the hollow portion 6 is preferably determined depending on the shape and dimensions of the conductor installed in the hollow portion 6.

The function of the magnetic core 1 in the first embodiment will be described.
FIG. 4 is a schematic configuration diagram of a current sensor having a general magnetic core. In the figure, the magnetic core 1 forms a magnetic circuit 9 together with the gap portion 3, and a magnetoelectric conversion element 11 is installed in the gap portion 3. When a conductor 10 is provided through the hollow portion 6 of the magnetic core 1 and a current to be measured flows through the conductor 10, a magnetic flux is generated according to the right-handed screw law. The magnitude of the magnetic flux generated at this time is a magnitude corresponding to the current to be measured. If a current to be measured flows in the + Z direction in FIG. 4, a magnetic flux 12 is generated in the magnetic circuit 9 in the direction of the arrow in FIG. 4. Since the gap portion 3 is an air layer, the magnetic permeability is lower than that of the magnetic material constituting the magnetic core 1 and a leakage magnetic flux is generated. However, since the magnetic flux passes through the installed magnetoelectric conversion element 11, the magnetoelectric conversion element 11 is Some detection signal that varies according to the magnitude of the magnetic flux is output. For example, when a Hall element is used as the magnetoelectric conversion element 11, a Hall voltage is output by the Hall effect according to the magnitude of the magnetic flux, that is, the magnitude of the current to be measured is measured.
FIG. 5 is a cross-sectional view of a gap portion, which is a part of a conventional magnetic core, disclosed in Patent Document 1 or 2. In the figure, the inner end portion 4a and the outer end portion 5a are constituted only by a flat portion, and both are arranged substantially in parallel via the gap portion 3a. When a current to be measured flows through the conductor and a magnetic flux flows through the magnetic core, a magnetic flux is generated in the gap portion 3a so as to connect the inner end portion 4a and the outer end portion 5a. In FIG. 5, the distribution outline of the magnetic flux lines 13a is represented by arrows. In both side portions of the inner end portion 4a and the outer end portion 5a, the magnetic flux lines are bent by the leakage magnetic flux, but in the gap portion 3a, the substantially parallel magnetic flux lines 13a are shown.
FIG. 3 is a cross-sectional view of the gap portion 3 according to the first embodiment. Unlike FIG. 5 showing the conventional example, the inner end portion 4 is processed into a convex shape having a flat portion 7 toward the outer end portion 5. The outer end 5 is composed only of a flat portion. When a conductor is installed in the hollow portion 6 and a current to be measured flows through the conductor and a magnetic flux flows through the magnetic core, the inner end portion 4 and the outer end portion 5 are connected to the gap portion 3 as in FIG. Magnetic flux is generated. However, since the shape of the inner end 4 is different, the distribution outline of the magnetic flux lines 13 is different from that shown in FIG. 5, and the magnetic flux concentrates on the convex tip portion, that is, the central portion of the gap portion 3. Is larger than the substantially parallel arrangement as shown in FIG.
As can be seen from the comparison between FIG. 3 and FIG. 5, even if the shape of the magnetic material excluding the end portion is the same and the magnitude of the magnetic flux generated in the magnetic material is the same except for the end portion, at least one magnetic material By changing the end shape, it is possible to vary the magnitude of the magnetic flux generated in the gap portion.

FIG. 6 shows a modification of a partial cross-sectional view in the first embodiment shown in FIG. 3, and the inner end 4b is processed into a concave shape having a flat portion 7b toward the outer end 5b. The outer end 5b is composed only of a flat portion. When a conductor is installed in the hollow portion 6 and a current to be measured flows through the conductor and a magnetic flux flows through the magnetic core, the inner end 4b and the outer end 5b are connected to the gap 3b as in FIG. Magnetic flux is generated. However, since the shape of the inner end portion 4b is different, the distribution outline of the magnetic flux lines 13b is different from that in FIG. 5, and the magnetic flux concentrates on the concave tip portion, that is, both side portions of the gap portion 3, and the magnitude of the magnetic flux in this portion. Is larger than the substantially parallel arrangement as shown in FIG.
As can be seen from the comparison between FIG. 5 and FIG. 6, even if the shape of the magnetic material excluding the end portion is the same and the magnitude of the magnetic flux generated in the magnetic material is the same except for the end portion, at least one magnetic material By changing the end shape, it is possible to vary the magnitude of the magnetic flux generated in the gap portion.

The adjustment of the measured current range by changing the shape of the end of at least one magnetic material will be described in an example in which one Hall element 14 is installed near the center of the gap as a magnetoelectric conversion element.
FIG. 7 is a schematic graph showing the Hall voltage that is the output of the Hall element 14 with respect to the measured current value. The three plots correspond to the end shapes of the magnetic materials shown in FIGS. 3, 5, and 6, respectively. As can be seen from FIG. 7, even if the shape of the magnetic core excluding the end of the magnetic material is the same and the magnitude of the magnetic flux generated in the magnetic material is the same except for the end, the end of at least one magnetic material By changing the shape, the magnitude of the magnetic flux generated in the gap can be varied. For example, when the current to be measured of A1 (A) flows in FIG. 7, the generated Hall voltage is different from X, Y, and Z corresponding to the end shape of the magnetic material even though the generated magnetic flux is the same. That is, the required Hall voltage and current range to be measured can be freely selected according to the end shape of the magnetic material. Although FIG. 7 shows that the Hall voltage changes linearly without limitation in accordance with the measured current value, the Hall voltage is actually limited by the voltage or current supplied to the Hall element. Since the Hall voltage is also limited by the saturation phenomenon of the magnetic properties of the selected magnetic material, the magnetic material is selected according to the required Hall voltage and the current range to be measured, and the dimensions such as the width and thickness of the magnetic material are determined. There is a need to.

Up to this point, an example in which one Hall element is installed as the magnetoelectric conversion element in the vicinity of the center of the gap portion has been described, but an example in which two Hall elements are further installed will be described.
8 is a cross-sectional view (a partial cross-sectional view of the magnetic core 1) showing a BB ′ cross-section (YZ plane) in FIG. Similar to the AA ′ cross section shown in FIG. 3, the inner end 4c is processed into a convex shape having a flat portion 7c toward the outer end 5c, and the outer end 5c is constituted only by a flat portion. Since the height of the convex shape is different, the interval 15 between the inner end 4c and the outer end 5c in the gap 3c is different from the AA ′ cross section. Similar to the partial cross section of the magnetic core shown so far, a magnetic flux is generated in the gap portion 3c so as to connect the inner end portion 4c and the outer end portion 5c. Similar to FIG. 3, although the magnetic flux concentrates on the convex portion of the convex shape, the flat portion 7c is enlarged, so the magnitude of the magnetic flux in this central portion is larger than that in FIG. Becomes smaller. FIG. 9 is a schematic graph showing the Hall voltage output with respect to the measured current value when the Hall element 14 is installed in each of the gap portions shown in FIGS. 3 and 8. These correspond to the end shapes of the magnetic materials shown in FIGS. 3 and 8, respectively. That is, at the position of the Hall element 14c, even if the current to be measured is relatively large, the magnitude of the magnetic flux applied to the Hall element 14c is small and suppressed, without worrying about the output limitation and the like. Measurement of a large current to be measured can be easily performed without increasing the outer dimension of the magnetic core. On the other hand, at the position of the Hall element 14, even when the current to be measured is slightly reduced, the degree of suppression of the magnetic flux applied to the Hall element 14 is small, and without worrying about the deterioration of S / N due to a decrease in output, etc. It is easy to measure a small current to be measured. Therefore, if the Hall element 14 is used when measuring a measured current with a small capacity, and the Hall element 14c is used when measuring a relatively large measured current, a Hall element having the same output characteristics can be used. By slightly adjusting the amplification factor and the like in the circuit portion of each Hall element, it becomes possible to construct a highly accurate current sensor with an expanded current range to be measured as shown in FIG.

In the first embodiment, an example in which the shape of only the inner end portion is varied has been described. However, the present invention is not limited to this, and the shape of only the outer end portion may be varied, or a desired magnetic flux size may be changed. Accordingly, the shapes of both the inner end portion and the outer end portion may be varied.
Further, in the first embodiment, at the end of the magnetic body 2, a convex portion or a concave portion is formed at right angles to the longitudinal x direction, but this is not restrictive, and the convex portion is perpendicular to the z direction. Alternatively, a recess may be formed.

  As described above, according to the first embodiment, the magnetic core is configured such that one magnetic material plate is bent into a substantially annular shape and a gap is formed between the ends of the magnetic material. Processing is easy and there is an effect of miniaturization.

  In addition, according to the magnetic core of the present invention, the shape of the end of at least one magnetic material is convex, concave, or at least one flat portion without changing the original dimensions of the plate material that is one magnetic material. By processing into a convex shape having or a concave shape having at least one flat portion, the magnitude of the magnetic flux in the gap portion where the magnetoelectric conversion element is installed can be easily varied, that is, the current range to be measured can be adjusted. The original magnetic material can be used in common for a plurality of specifications, and it is not necessary to have a magnetic material having a plurality of dimensions, which has the effect of reducing costs.

  In addition, according to the magnetic core of the present invention, since the original shape of the plate material, which is a single magnetic material, is a rectangle, there is no unnecessary part in removing material from the base material plate, reducing waste loss. As a result, the design is environmentally friendly and has the effect of reducing costs.

  Furthermore, because there is a structure where there are different magnetic flux sizes in the gap, the installation of multiple magnetoelectric transducers in the gap of the magnetic core makes it possible to reduce the size and increase the measurement range with high accuracy. There is.

Embodiment 2. FIG.
FIG. 11 is a perspective view of a current sensor according to Embodiment 2 of the present invention. In the figure, the current sensor 16 includes a magnetic core 1, a Hall element 14, a sensor circuit unit 17, a sensor substrate 19 having an external terminal 18, and a conductor 10.
The second embodiment has a configuration in which a sensor substrate 19 having a hall element 14, a sensor circuit unit 17, and an external terminal 18 and a conductor 10 are newly added to the magnetic core 1 shown in the first embodiment. The magnitude of the current to be measured flowing through is output as an electrical signal corresponding to the magnitude of the current to be measured. In addition, since the description about the magnetic core 1 overlaps, it abbreviate | omits.

The overall configuration of the current sensor 16 in the second embodiment will be described.
In the second embodiment, the magnetic core 1 has a structure in which the inner end 4 has a convex shape toward the outer end 5 as shown in FIG. 1 of the first embodiment, and has the outer end 5. On one surface of the magnetic core 1 on the gap portion 3 side, a sensor substrate 19 having a shape substantially coincident with the magnetic material width is installed. Although the method of installing the sensor substrate 19 is not particularly illustrated, it is assumed that the sensor substrate 19 is formed by an adhesive, resin molding, screwing to the magnetic core 1, or the like, and here, an example in which the sensor substrate 19 is attached via the adhesive is shown.
On the sensor substrate 19, one Hall element 14 as a magnetoelectric conversion element and the sensor circuit portion 17 are arranged, and the magnitude of the current to be measured flowing through the conductor 10 installed through the hollow portion 6 is set to a predetermined electrical level. A signal is output via the external terminal 18. The Hall element 14 is not only mechanically installed on the sensor substrate 19 but also electrically connected so as to be electrically connected to the sensor circuit unit 17. The installation position of the Hall element 14 on the sensor substrate 19 is a position facing the convex shape of the inner end portion 4 in the Z direction, and the magnitude of the magnetic flux to be applied to the Hall element 14 in the X direction and the Y direction. That is, it is determined according to the magnitude of the current to be measured. Particularly in the Y direction, the installation position is adjusted by changing the thickness of the sensor substrate 19 according to the determined position. Here, an example in which one Hall element 14 is installed is shown, but as described in the modification of the first embodiment, two or more Hall elements may be installed. A Hall IC in which a Hall element is incorporated and a processing circuit or the like is integrated may be used.
The sensor circuit unit 17 supplies a constant voltage or a constant current to the Hall element 14, and performs a process such as appropriate amplification on the Hall voltage generated according to the magnitude of the applied magnetic flux and outputs the Hall voltage. In order to electrically connect the current sensor 16 and an external input / output terminal, an external terminal 18 is used.
The conductor 10 through which the current to be measured flows is installed through the hollow portion 6. Here, an example in which the number of conductors 10 passing through the hollow portion 6 is one is shown. However, in order to increase the magnetic flux applied to the magnetic core 1, the conductor 10 is wound around the magnetic material constituting the magnetic core 1 a plurality of times. It is good also as the structure which carried out.

Next, the operation of the current sensor 16 will be described.
When a current to be measured flows through the conductor 10, a magnetic flux is generated according to the right-handed screw law, and the magnitude of the magnetic flux generated at this time is a magnitude corresponding to the current to be measured. The magnetic flux stably flows in the magnetic material having a high magnetic permeability constituting the magnetic core 1 and passes through the Hall element 14 installed in the gap portion 3. The Hall element 14 generates a Hall voltage due to the Hall effect in accordance with the magnitude of the magnetic flux, and the magnitude of the generated magnetic flux through the external terminal 18 via the connected sensor circuit unit 17, that is, the current to be measured. An electrical signal corresponding to the size is output to the outside. In this way, the current to be measured flowing through the conductor 10 is measured.
In the present embodiment, the magnetic core 1 is configured to output an electric signal corresponding to the magnitude of the generated magnetic flux, that is, the magnitude of the current to be measured, to the outside. A magnetic balance type configuration may be employed in which a conductive wire is wound and current is supplied to the compensation conductive wire based on the Hall voltage generated by the Hall element 14 so as to cancel the magnetic flux flowing in the magnetic material.

  As described above, according to the second embodiment, since the sensor substrate having the Hall element, the sensor circuit unit, and the external terminal is arranged on the magnetic core including the gap portion 3, the magnetic field described in the first embodiment is used. The current sensor 1 can be constructed without enlarging the outer dimension of the core, and there is an effect of downsizing.

DESCRIPTION OF SYMBOLS 1 Magnetic core, 2 Magnetic material, 3 Gap part, 4 Inner edge part, 5 Outer edge part, 6 Hollow part, 7 Flat part, 8 Refraction part, 9 Magnetic circuit, 10 Conductor, 11 Magnetoelectric conversion element, 12 Flow of magnetic flux , 13 Magnetic flux lines, 14 Hall elements, 15 Space between each end, 16 Current sensor, 17 Sensor circuit part, 18 External terminal, 19 Sensor substrate

Claims (5)

  In a magnetic core in which a magnetic circuit is formed by at least one plate-like magnetic material and a gap portion formed by a gap formed between the end portions of the magnetic material by bending the magnetic material in a substantially annular shape. The magnetic core is characterized in that both end portions of the magnetic material face each other with a predetermined distance and a predetermined area to form a gap portion, and the opposing surface of at least one end portion is processed into a convex shape.   In the magnetic core, both end portions of the magnetic material are opposed to each other with a predetermined distance and a predetermined area to form a gap portion, and at least one opposite end surface is formed with a convex portion having at least one flat portion. Magnetic core characterized by being processed into a shape.   In the magnetic core, both end portions of the magnetic material are opposed to each other with a predetermined distance and a predetermined area to form a gap portion, and a facing surface of at least one end portion is processed into a concave shape. Magnetic core.   In the magnetic core, both end portions of the magnetic material are opposed to each other with a predetermined distance and a predetermined area to form a gap portion, and at least one end portion facing surface is a concave shape having at least one flat portion. Magnetic core characterized by being processed into   A magnetic core according to any one of claims 1 to 4, at least one magnetoelectric conversion element installed in the gap portion, and a sensor circuit unit connected to the magnetoelectric conversion element, the magnetoelectric conversion element Is held at a predetermined position of the gap portion, and a sensor substrate on which the sensor circuit portion is installed is fixed to the magnetic core.

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