JP2015152390A - current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current sensor capable of accurately measuring a wide range current on a small scale and at a low cost.SOLUTION: In the inside of a magnet field control part 5, the width in the X direction of the region on a central magnetic field control part 21 side surrounded by a second inner face region 23a and a second inner face region 25a is shorter in comparison with that in the X-direction of the region on the opening 27 side surrounded by a first inner face region 23a and a first inner face region 25a. In the region surrounded by the inner face region 23a and the first inner face region 25a, a substrate 17 is located to which the magnetic field control part 5 is fixed. The magnetic field control part 5 detects a magnetic field generated by a current flowing through a bus bar 6.

Description

  The present invention relates to a current sensor that detects a current flowing through a current path (bus bar).

There is a current sensor that detects a magnetic flux density of a magnetic field generated when a current flows through a bus bar by a magnetic detection unit (for example, GMR: Giant Magneto Resistive effect) and converts it into an electric signal.
Such current sensors include, for example, one that prioritizes the stability of the current magnetic field and arranges the sensor at a point where the current magnetic field strength in the shield structure is minimized.
However, in such a current sensor, there is a problem that when a minute current is detected, the corresponding magnetic field becomes too small and it is difficult to ensure measurement accuracy.

JP 2013-62457 A

Incidentally, in order to measure a small amount of current more accurately, it is necessary to increase the magnetic flux density. For this purpose, it is necessary to narrow the gap (width) of the magnetic field control plate surrounding the bus bar.
However, since the magnetic detection unit using the magnetoresistive effect element detects a magnetic field by sensitivity in the plane direction, it needs a certain size or more in the plane direction, and it is difficult to shorten the gap. That is, if the entire gap is shortened, there is a problem in that a space for arranging the magnetic detection unit together with the substrate cannot be secured in the magnetic field control plate.
Further, if the entire gap is shortened, the magnetic field control plate is magnetically saturated, and the linearity with respect to the magnitude of the bus bar current cannot be maintained, and there is a problem that the current range that can be measured is small.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a current sensor that can accurately measure a wide range of currents on a small scale and at low cost.

  The current sensor according to the present invention includes a current path having a shape in which a cross section perpendicular to the current direction is line symmetric with respect to a virtual symmetry axis, and a substrate having a facing surface perpendicular to the symmetry axis and facing the current path. And a magnetic sensor that is disposed on the facing surface and detects a magnetic field generated by a current flowing in the current path, and a continuous inner surface that surrounds the substrate and the current path, and in a cross section orthogonal to the current direction. A magnetic field control means made of a magnetic material having a contour line corresponding to the inner surface and a shape symmetrical with respect to the symmetry axis, and the inner surface of the magnetic field control means has the symmetry axis at the position of the opposing surface. A pair of first inner surface regions opposed to each other and a pair of second inner surface regions located across the current path at the position of the current path facing the facing surface, the pair of second inner regions The inner surface area of the pair of first Compared with the inner surface area, the distance in the axis of symmetry perpendicular direction it is narrower.

In the current sensor of the present invention, when a current flows through the current path, a magnetic field is generated around the current path, and a magnetic flux density corresponding to the strength of the magnetic field is generated.
At this time, a magnetic flux density corresponding to the shape of the magnetic field control means is generated in the magnetic field control means, and this is detected by the magnetic sensor.

Inside the magnetic field control means of the current sensor of the present invention, the width in the direction orthogonal to the symmetry axis of the region surrounded by the pair of second inner surface regions is the width of the region surrounded by the pair of first inner surface regions. Shorter than
Therefore, the magnetic flux density inside the magnetic field control means is increased by shortening the distance between the second inner surface region and the current path while providing a sufficient width for arranging the substrate between the pair of first inner surface regions. Can do.
In addition, the current sensor of the present invention can prevent the magnetic field control means from being magnetically saturated and unable to maintain linearity with respect to the current magnitude of the bus bar, compared with the case where the entire gap is shortened. Can be detected.

Preferably, the first inner surface region and the second inner surface region of the magnetic field control means of the current sensor of the present invention are substantially parallel to the symmetry axis.
Thereby, the magnetic flux density in the said magnetic field control means can be raised.

Preferably, the magnetic field control means of the current sensor of the present invention includes a third inner surface region that is substantially orthogonal to the axis of symmetry between the first inner surface region and the second inner surface region. .
According to this configuration, since the third inner surface region is orthogonal to the symmetry axis, the length of the first inner surface region and the second inner surface region in the direction of the symmetry axis can be increased. Thereby, the magnetic field control characteristic by a magnetic control means can be improved.
Preferably, in the current sensor according to the present invention, the magnetic sensor is positioned adjacent to the third inner surface region in a direction in which the axis of symmetry extends.
According to this configuration, the magnetic sensor is disposed in a region having a high magnetic flux density close to the third inner surface region in the direction in which the symmetry axis extends.

Preferably, the magnetic field control means of the current sensor according to the present invention sets a distance from the symmetry axis between the first inner surface region and the second inner surface region as it approaches the first inner surface region. A third inner surface area which is a curved surface to be increased is provided.
According to this configuration, since the third inner surface region is a curved surface that increases the distance from the symmetry axis as it approaches the first inner surface region, the substrate is placed in or near the third inner surface region. A region having a sufficient width and a region having a high magnetic flux density shorter than the region can be formed, and a magnetic sensor can be disposed in the region having the high magnetic flux density.
Thereby, the magnetic field control characteristic by a magnetic control means can be improved.
Preferably, in the current sensor of the present invention, the magnetic sensor is located at the same position as the third inner surface region in the direction in which the axis of symmetry extends.
According to this configuration, the magnetic sensor is arranged in a region having a high magnetic flux density near the third inner surface region in the direction in which the symmetry axis extends.

  According to the present invention, it is possible to provide a current sensor that can accurately measure a wide range of currents on a small scale and at low cost.

FIG. 1 is a perspective view of a current sensor according to a first embodiment of the present invention. 2 is an external view of the current sensor shown in FIG. 1 viewed from the Y direction. FIG. 3 is a diagram illustrating a result of a magnetic field simulation performed when a current is passed through the bus bar in the current sensor illustrated in FIGS. 1 and 2. FIG. 4 is a perspective view of a current sensor of a comparative example. FIG. 5 is a diagram showing a result of a magnetic field simulation performed when a current is passed through the bus bar in the current sensor shown in FIG. FIG. 6 shows a case where the magnetic flux density at the position of the magnetic sensor module in the current sensor of the embodiment of the present invention and the comparative example is shown. FIG. 7 is a perspective view of the current sensor 1 according to the second embodiment of the present invention. FIG. 8 is an external view of the current sensor 1 shown in FIG. 7 as viewed from the Y direction. FIG. 9 is a diagram illustrating a result of performing a magnetic field simulation when a current is passed through the bus bar in the current sensor illustrated in FIGS. 7 and 8.

Hereinafter, a current sensor according to an embodiment of the present invention will be described.
<First Embodiment>
FIG. 1 is a perspective view of a current sensor 1 according to the first embodiment of the present invention.
FIG. 2 is an external view of the current sensor 1 shown in FIG. 1 viewed from the Y direction.
The current sensor 1 adjusts the magnetic field strength in the magnetic field control unit without changing the product outer shape by devising the shape of the magnetic field control unit made of a magnetic material.
1 and 2, the bus bar 6 is an example of the current path of the present invention, the substrate 17 is an example of the substrate of the present invention, the magnetic sensor module 3 is an example of the magnetic sensor of the present invention, and the first The inner surface regions 23a and 25a are an example of the first inner surface region of the present invention, the second inner surface region 23e and 25e are an example of the second inner surface region of the present invention, and the third inner surface regions 23c and 25c are It is an example of the 3rd inner surface field of the present invention.

As shown in FIGS. 1 and 2, the current sensor 1 detects a magnetic field generated from the current flowing through the bus bar 6.
The current sensor 1 includes a magnetic sensor module 3 and a magnetic field control unit (yoke) 5.
The Y-direction path 6a of the bus bar 6 has a shape (for example, a rectangle) in which the cross section perpendicular to the current direction (Y direction) is line-symmetric with respect to the virtual symmetry axis 11. The symmetry axis 11 is orthogonal to the current direction (Y direction) of the bus bar 6.

[Magnetic sensor module 3]
The magnetic sensor module 3 is located inside the magnetic field controller 5. The magnetic field control unit 5 is a magnetoresistive effect element such as GMR, for example, and detects a magnetic field based on the sensitivity in the plane direction (X, Y plane).

  The magnetic sensor module 3 is fixed to the facing surface 17a of the substrate 17 facing the surface 6a1 of the Y-direction path 6a of the curved portion of the bus bar 6 orthogonal to the symmetry axis 11.

[Magnetic field controller 5]
As shown in FIG. 2, the magnetic field control unit 5 has a shape in which a cross section perpendicular to the current direction (Y direction) of the bus bar 6 is line symmetric with respect to the symmetry axis 11.
The magnetic field control unit 5 is a magnetic material.
In the magnetic field control unit 5, a central magnetic field control unit 21 and Z-direction magnetic field control units 23 and 25 are integrally formed. By integrally molding in this way, it can be easily manufactured from one magnetic plate, and the cost can be reduced.
The magnetic field control unit 5 has a continuous inner surface that surrounds the substrate 17, the magnetic sensor module 3, and the bus bar 6, and the contour line corresponding to the inner surface is symmetrical with respect to the symmetry axis 11 in the cross section.
An opening 27 is formed between the Z direction magnetic field control unit 23 and the Z direction magnetic field control unit 25.

The central magnetic field controller 21 has a flat surface 21a orthogonal to the inner surfaces 23a, 25a of the Z direction magnetic field controllers 23, 25.
The flat surface 21a of the central magnetic field control unit 21 is positioned to face the flat surface 6a2 of the Y-direction path 6a of the curved portion of the bus bar 6 with a predetermined distance therebetween.
The bus bar 6 has a curved portion with a U-shaped cross section, and is positioned so as to cover the central magnetic field control unit 21 of the magnetic field control unit 5. The central magnetic field control unit 21 is located inside the recessed portion of the curved portion of the bus bar 6.

As shown in FIG. 2, the Z-direction magnetic field control unit 23 sequentially has a first inner surface region 23 a, an inner surface region 23 b, a third inner surface region 23 c, and an inner surface region 23 d from the opening 27 toward the central magnetic field control unit 21. And a second inner surface region 23e, which are integrally formed.
The first inner surface area 23a is parallel to the Y and Z planes, the inner surface area 23b is a curved surface having a ¼ arc, the third inner surface area 23c is parallel to the X and Y planes, and the inner surface area 23d is 1 / 4 arc surface, and the second inner surface region 23e is parallel to the Y and Z planes.
The second inner surface region 23e is located on the symmetry axis 11 side with respect to the first inner surface region 23a.

The Z-direction magnetic field control unit 25 is line-symmetric with the Z-direction magnetic field control unit 23 with respect to the symmetry axis 11 in a cross section orthogonal to the Y direction.
As shown in FIG. 2, the Z-direction magnetic field control unit 25 is arranged in order from the opening 27 toward the central magnetic field control unit 21 in the first inner surface region 25a, the inner surface region 25b, the third inner surface region 25c, and the inner surface region 25d. And a second inner surface region 25e, which are integrally formed.
The first inner surface region 25a is parallel to the Y and Z planes, the inner surface region 25b is a curved surface having a ¼ arc, the third inner surface region 25c is parallel to the X and Y planes, and the inner surface region 25d is 1 The curved surface is a / 4 arc, and the second inner surface region 25e is parallel to the Y and Z planes.
The second inner surface region 25e is located on the symmetry axis 11 side with respect to the first inner surface region 25a.

As shown in FIG. 2, inside the magnetic field controller 5, the width in the X direction of the region surrounded by the second inner surface region 23 e and the second inner surface region 25 e is the same as that of the first inner surface region 23 a and the first inner region 23 e. This is shorter than the width in the X direction of the region surrounded by the inner surface region 25a.
As shown in FIG. 2, the substrate 17 is located in a region surrounded by the first inner surface region 23a and the first inner surface region 25a. Therefore, a sufficient space for the substrate 17 can be secured. The distance in the X direction between the first inner surface region 23a and the first inner surface region 25a is determined according to the length of the substrate 17 in the X direction.

The magnetic sensor module 3 is fixed to the facing surface 17a of the substrate 17 and is substantially in the vicinity of the positions of the third inner surface regions 23c and 25c in the Z direction. The position is a region where the magnetic flux density is relatively high, and the sensitivity characteristic of current measurement of the magnetic sensor module 3 can be enhanced.
Further, the Y-direction path 6a of the bus bar 6 is located in a region surrounded by the second inner surface region 23e and the second inner surface region 25e. Therefore, the distance between the second inner surface regions 23d and 25d and the bus bar 6 can be shortened, and the magnetic flux density inside the magnetic field controller 5 can be increased. The distance in the X direction between the second inner surface region 23e and the second inner surface region 25e is determined according to the width in the X direction of the Y path portion 6a of the bus bar 6.

  In the magnetic sensor module 3, since the third inner surface regions 23c and 25c are parallel to the X and Y planes, the first inner surface region 23a and the first inner surface region 25a parallel to the Y and Z directions, and the second The length in the Z direction of the inner surface area 23e and the second inner surface area 25e can be increased. Thereby, the magnetic field control characteristic by the magnetic control part 5 can be improved.

[Bus bar 6]
The bus bar 6 has a curved portion having a U-shaped cross section.
In a region surrounded by the second inner surface region 23e and the second inner surface region 25e of the magnetic field control unit 5, the bus bar 6 has a flat surface 6a2 (a flat surface 6a of the Y path portion 6a) of the depressed portion of the curved portion. It arrange | positions with the attitude | position which faces the inner surface 21a of the central magnetic field control part 21 of the magnetic field control part 5. FIG.
That is, the bus bar 6 is positioned so as to cover the central magnetic field control unit 21 of the magnetic field control unit 5. The central magnetic field control unit 21 is located inside the recessed portion of the curved portion of the bus bar 6.
Thereby, it is not necessary to change the position of the bus bar connected to both ends of the bus bar 6 shown in FIG. 1, and the current sensor 1 can be easily surface-mounted on the substrate of the final product.

Hereinafter, the operation of the current sensor 1 will be described.
When a current flows through the bus bar 6, a magnetic field is generated around the bus bar 6, and a magnetic flux density corresponding to the strength of the magnetic field is generated.
At this time, a magnetic flux density shown in FIG. 3 corresponding to the shape of the magnetic field control unit 5 is generated around the magnetic field control unit 5.
And the detection signal according to the magnetic flux detected with the magnetic sensor module 3 is output to a control part.
In the control unit, the detection signal is amplified by the amplifier circuit, and a voltage value having a value proportional to the detected magnetic field strength is output.
Thus, based on the output from the magnetic sensor module 3, the value of the current flowing through the bus bar 6 is detected.

FIG. 3 is a diagram illustrating a result of a magnetic field simulation performed when a current is passed through the bus bar 6 in the current sensor 1 illustrated in FIGS. 1 and 2.
As shown in FIG. 3, it can be seen that the magnetic flux density in the areas 31, 33, and 35 inside and around the magnetic field control unit 5 is higher than in other areas.
In the current sensor 1, as shown in FIG. 2, the magnetic field controller 5 is arranged in a region 35 having a high magnetic flux density shown in FIG. 3.

FIG. 4 is a perspective view of the current sensor 101 of the comparative example.
The magnetic field controller 105 of the current sensor 101 shown in FIG. 4 has a U-shaped cross section.
FIG. 5 is a diagram showing a result of performing a magnetic field simulation by passing a current through the bus bar 6 in the current sensor 101 shown in FIG.
According to the current sensor 101, as shown in FIG. 5, the magnetic flux density in the regions 131, 133, and 135 inside and around the magnetic field control unit 105 is higher than in other regions.
In the current sensor 101, as shown in FIG. 4, the magnetic field controller 5 is arranged in a region 135 having a high magnetic flux density shown in FIG.
As shown in FIG. 6, the region 35 where the magnetic field control unit 5 of the current sensor 1 is disposed has a higher magnetic flux density than the region 135 where the magnetic field control unit 105 of the current sensor 101 is disposed, and the magnetic field control unit 5 can increase the internal magnetic flux density as compared with the magnetic field controller 105.

As described above, according to the current sensor 1, the width in the X direction of the region surrounded by the second inner surface region 23e and the second inner surface region 25e is equal to the first inner side of the magnetic field control unit 5. The width is shorter than the width in the X direction of the region surrounded by the inner surface region 23a and the first inner surface region 25a.
Therefore, the distance between the second inner surface regions 23e and 25e and the bus bar 6 is shortened while providing a sufficient width for disposing the substrate 17 between the first inner surface region 23a and the first inner surface region 25a. The magnetic flux density inside the magnetic field controller 5 can be increased.
Further, by arranging the magnetic sensor module 3 in the region 35 having a high magnetic flux density in the magnetic field control unit 5, the sensitivity of current detection is increased, and a small current can be achieved with high accuracy.

  In addition, the current sensor 1 can prevent the magnetic field control unit 5 from being magnetically saturated and unable to maintain linearity with respect to the magnitude of the current of the bus bar as compared with the case where the entire gap is shortened. It can be detected.

In the current sensor 1, the magnetic field control unit 5 can be formed by relatively simple processing, and can be manufactured at a low price.
That is, the current sensor 1 can measure a wide range of currents with high accuracy at a small scale and at low cost.

Second Embodiment
FIG. 7 is a perspective view of a current sensor 201 according to the second embodiment of the present invention.
FIG. 8 is an external view of the current sensor 201 shown in FIG. 7 viewed from the Y direction.

As shown in FIGS. 7 and 8, the current sensor 201 detects a magnetic field generated from the current flowing through the bus bar 6.
The current sensor 201 includes a magnetic sensor module 3 and a magnetic field control unit 205.
7 and 8, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG.
That is, in the current sensor 201, the magnetic field control unit 205 is different from the magnetic field control unit 5 of the first embodiment.

Hereinafter, the magnetic field control unit 205 will be mainly described.
As shown in FIGS. 7 and 8, the magnetic field control unit 205 is a magnetic body and has a shape in which a cross section perpendicular to the current direction (Y direction) of the bus bar 6 is line symmetric with respect to the symmetry axis 211. doing.
In the magnetic field control unit 205, a central magnetic field control unit 221 and Z-direction magnetic field controls 223 and 225 are integrally formed.

The central magnetic field control unit 221 has a flat surface 221a orthogonal to the inner surfaces 223a and 225a of the Z-direction magnetic field control units 223 and 225.
The plane 221a of the central magnetic field controller 221 is positioned to face the plane 6a2 of the Y-direction path 6a of the curved portion of the bus bar 6 with a predetermined distance therebetween.

As shown in FIG. 8, the Z-direction magnetic field control unit 223 includes a first inner surface region 223 a, a third inner surface region 223 b, and a second inner surface region in order from the opening 227 toward the central magnetic field control unit 221. 223c is integrally formed.
The first inner surface region 223a is parallel to the Y and Z planes, and the third inner surface region 223b is a curved surface that increases the distance from the symmetry axis 211 as it approaches the first inner surface region 223a. 223c is parallel to the Y and Z planes.
The second inner surface region 223c is located on the symmetry axis 211 side with respect to the first inner surface region 223a.

The Z-direction magnetic field control 225 is line-symmetric with the Z-direction magnetic field control 223 with respect to the symmetry axis 211 in a cross section orthogonal to the Y direction.
As shown in FIG. 8, the Z-direction magnetic field control unit 225 has a first inner surface region 225 a, a third inner surface region 225 b, and a second inner surface region 225 c in order from the opening 227 toward the central magnetic field control unit 221. And are integrally molded.
The first inner surface region 225a is parallel to the Y and Z planes, and the third inner surface region 225b is a curved surface that increases the distance from the symmetry axis 211 as it approaches the first inner surface region 225a. 225c is parallel to the Y and Z planes.
The second inner surface region 225c is located on the symmetry axis 211 side with respect to the first inner surface region 225a.

As shown in FIG. 8, inside the magnetic field control unit 205, the width in the X direction of the region surrounded by the second inner surface region 223c and the second inner surface region 225c is the same as that of the first inner surface region 223a and the first inner region 223a. This is shorter than the width in the X direction of the region surrounded by the inner surface region 225a.
As shown in FIG. 7, the substrate 17 is located in a region surrounded by the first inner surface region 223a and the first inner surface region 225a. Therefore, a sufficient space for the substrate 17 can be secured.

The magnetic sensor module 3 is fixed to the facing surface 17a of the substrate 17 and is in a position surrounded by substantially third inner surface regions 223b and 225b in the Z direction. The position is a region where the magnetic flux density is relatively high, and the sensitivity characteristic of current measurement of the magnetic sensor module 3 can be enhanced.
Further, the Y-direction path 6a of the bus bar 6 is located in a region surrounded by the second inner surface region 223c and the second inner surface region 225c. Therefore, the distance between the second inner surface regions 223c and 225c and the bus bar 6 can be shortened, and the magnetic flux density inside the magnetic field controller 5 can be increased.

FIG. 9 is a diagram illustrating a result of a magnetic field simulation performed when a current is passed through the bus bar 6 in the current sensor 201 illustrated in FIGS. 7 and 8.
According to the current sensor 201, as shown in FIG. 9, it can be seen that the magnetic flux density in the areas 231, 233 and 235 inside and around the magnetic field control unit 205 is higher than in other areas. In the current sensor 201, as shown in FIG. 8, the magnetic field controller 5 is arranged in a region 235 having a high magnetic flux density shown in FIG.
As shown in FIG. 6, the region 235 in which the magnetic field control unit 205 of the current sensor 201 is disposed has a higher magnetic flux density than the region 135 in which the magnetic field control unit 5 of the current sensor 101 is disposed, and the magnetic field control unit It can be seen that 205 can increase the internal magnetic flux density as compared with the magnetic field control unit 105.

As described above, the current sensor 201 can provide the same effect as the current sensor 1 of the first embodiment.
According to the current sensor 201, the third inner surface region 223b, 225b of the magnetic control unit 205 is a curved surface that increases the distance from the symmetry axis 211 as it approaches the first inner surface region 223a, 225a. A region having a sufficient width for installing the substrate 17 and a region having a high magnetic flux density shorter than the region can be formed in or near the regions 223b and 225b, and the magnetic sensor 3 is disposed in the region having the high magnetic flux density. can do.

The present invention is not limited to the embodiment described above.
That is, those skilled in the art may make various modifications, combinations, subcombinations, and alternatives regarding the components of the above-described embodiments within the technical scope of the present invention or an equivalent scope thereof.

  Moreover, the shape of the magnetic field control units 5 and 205 shown in the present embodiment is an example, and can be modified within the scope of the claims.

  The present invention is applicable to, for example, a current sensor that detects current using a magnetoresistive effect element.

DESCRIPTION OF SYMBOLS 1,201 ... Current sensor, 3 ... Magnetic sensor module, 5 ... Magnetic field control part, 6 ... Busbar, 17 ... Board | substrate, 21,221 ... Central magnetic field control part, 23, 25, 223, 225 ... Z direction magnetic field control part, 23a, 25a, 223a, 225a ... first inner surface region, 23c, 25c, 223c, 225c ... third inner surface region, 23e, 25e, 223c, 225c ... second inner surface region

Claims (7)

A current path in which a cross section perpendicular to the current direction has a line-symmetric shape with respect to a virtual symmetry axis;
A substrate orthogonal to the axis of symmetry and having a facing surface facing the current path;
A magnetic sensor that is disposed on the facing surface and detects a magnetic field generated by a current flowing in the current path;
Magnetic field control comprising a continuous inner surface surrounding the substrate and the current path, and a magnetic material made of a magnetic material in which a contour line corresponding to the inner surface is symmetrical with respect to the symmetry axis in a cross section orthogonal to the current direction Means and
The inner surface of the magnetic field control means is
A pair of first inner surface regions facing each other across the axis of symmetry at the position of the facing surface;
A pair of second inner surface regions located across the current path at the position of the current path facing the facing surface,
The pair of second inner surface regions have a smaller separation distance in a direction perpendicular to the symmetry axis than the pair of first inner surface regions. The current sensor according to claim 1, wherein the first inner surface region and the second inner surface region are substantially parallel to the symmetry axis.   The magnetic field control means includes a third inner surface region that is substantially orthogonal to the symmetry axis between the first inner surface region and the second inner surface region. The current sensor according to claim 3, wherein the magnetic sensor is positioned adjacent to the third inner surface region in a direction in which the axis of symmetry extends. The magnetic field control means is a third inner surface region that is a curved surface that increases the distance from the symmetry axis as approaching the first inner surface region between the first inner surface region and the second inner surface region. The current sensor according to claim 2. The current sensor according to claim 5, wherein the magnetic sensor is located at the same position as the third inner surface region in a direction in which the axis of symmetry extends. The current path has a curved portion with a U-shaped cross section,
The central magnetic field control unit that constitutes a part of the magnetic field control means, the second inner surface region is positioned on both sides, and intersects with the symmetry axis is positioned inside the recessed portion of the curved portion of the current path. The current sensor according to any one of claims 1 to 6.