JP2000284000A - Electric current detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric current detector of thin type easy in assembling, as to the current detector for detecting contactlessly an electric current flowing in a conductor by measuring the intensity of a magnetic field generated by the current. SOLUTION: The first magnetic substance plate 5 formed into a U-shaped plane, of which a connecting part 9 is bent in an arrow mark-Z direction so that a coupling part 7 and a gap part 8 in parallel to each other have a step difference in the Z-direction, and the second magnetic substance plate 6 having a plane shape of U-shape similar to the first plate 5, of which a connecting part 12 is bent in the arrow mark-Z direction so that a coupling part 10 and a gap part 11 in parallel to each other have a step difference in the Z-direction are welded mutually at the coupling part 7 and the coupling part 10, and the gap part 8 is overlapped with the gap part 11 so as to form a gap G.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current detecting device, and more particularly to a current detecting device for detecting a current flowing through a conductor in a non-contact manner by measuring a magnitude of a magnetic field generated by the current.

[0002]

2. Description of the Related Art When a current flows through one conductor, a magnetic field is generated in a circumferential direction around the conductor. FIG. 6 shows a perspective view of an example of the related art. The conventional current detection device 200 includes a magnetic path forming unit 201, a magnetic sensor 202, and a circuit board 203. The magnetic path forming portion 201 has an annular shape having a gap G. The magnetic path forming unit 201 is formed by laminating magnetic plates or sintering a magnetic material such as ferrite.

A gap G is formed by abutting the end faces of the magnetic path forming portion 201. Magnetic sensor 2
Numeral 02 detects a magnetic flux inserted in the gap G and penetrating the gap G. The cross section of the magnetic path forming portion 201 is formed so as to have substantially the area of the detection portion of the magnetic sensor 202 so that magnetic flux is supplied to the magnetic sensor 202 efficiently.

[0004] The magnetic sensor 202 is mounted on a circuit board 203. At this time, to reduce the size, the circuit board 203 is used.
Are arranged parallel to the magnetic path forming surface of the magnetic path forming section 201.
For this reason, the magnetic sensor 202 uses an axial type package and is vertically mounted on the circuit board 203. The cable 204 through which the non-measurement current I flows passes through the center hole 205 of the magnetic path forming unit 201. Cable 204
, A magnetic field is generated around the cable 204.

FIG. 7 is a diagram for explaining the operation of a conventional example. As shown in FIG. 7, when a current I flows through the cable 204, a magnetic flux H is generated according to the right-hand screw rule of ampere. At this time, the magnitude of the generated magnetic flux H is a magnitude corresponding to the current I flowing through the cable 204. 7 to cable 204
When the magnetic flux H is generated as shown in FIG. 6, the magnetic flux flows through the magnetic path forming section 201 in the order of a → b → c → d in FIG. The magnetic flux penetrates from end 206 to end 207 at gap G.

FIG. 8 is a diagram showing a state where a magnetic flux passes through a gap. As shown in FIG. 8, the magnetic flux H emitted from the end 206 of the magnetic path forming unit 201 is diffused by the gap G,
It converges again and is supplied to the end 207. Magnetic path forming unit 20
1 is supplied to the magnetic sensor 202 disposed in the gap G. The magnetic sensor 202 outputs a detection signal according to the magnitude of the magnetic flux.

The detection signal detected by the magnetic sensor 202 is supplied to a circuit board 203. An amplification circuit is mounted on the circuit board 203, and a detection signal detected by the magnetic sensor 202 is amplified and output.

[0008]

However, in the conventional current detecting device 200, the magnetic path forming portion 201 is required for miniaturization.
Of the magnetic sensor 2
Since it is necessary to make the area of the detecting unit 02 as large as possible, it is necessary to accurately position the magnetic path forming unit 201 and the magnetic sensor 202, and thus there is a problem that it takes time to assemble.

The magnetic path forming unit 201 and the magnetic sensor 20
2 must be accurately positioned, the magnetic sensor 202 must be mounted on the circuit board 203 after the magnetic path forming unit 201 and the magnetic sensor 202 have been positioned, and the magnetic path forming unit 201 is integrated. Magnetic sensor 202
Is mounted on the circuit board 203, so that soldering or the like cannot be easily performed, and therefore, there is a problem that it takes a long time to assemble.

Further, an axial type magnetic sensor 202 is used, and the magnetic sensor 202 is mounted on a circuit board 203.
, The thickness, that is, the size in the direction of the arrow Z becomes large, and there is a problem that miniaturization is difficult. In addition, since the cross-sectional area of the magnetic path forming unit 201 is made equal to the surface area of the magnetic sensor 202 for miniaturization, it is necessary to position the magnetic path forming unit 201 and the magnetic sensor 202 with high accuracy.

The present invention has been made in view of the above points, and has as its object to provide a thin and easy-to-assemble current detecting device.

[0012]

According to the present invention, there is provided a current detecting device for detecting a current by detecting a magnetic field generated around the current by the current, wherein the current detecting device is arranged around the current.
A magnetic path of magnetic flux generated according to the current, a magnetic path forming means in which a gap is formed so that the magnetic flux penetrates in a direction substantially perpendicular to the direction of the magnetic flux, and a magnetic path forming means disposed in the gap and the magnetic flux flowing in the gap. And a magnetic detecting means for detecting.

According to the present invention, since the gap is formed so that the magnetic flux penetrates in a direction substantially perpendicular to the direction of the magnetic flux generated according to the current to be detected, the magnetic flux is detected substantially in parallel with the direction in which the magnetic flux flows. Since the means can be arranged, the thickness can be reduced. Further, since the magnetic flux flowing through the gap is set in a direction substantially orthogonal to the magnetic flux generated according to the current, the area of the gap can be increased by increasing the overlapping area at both ends of the magnetic path forming means, The positioning accuracy between the magnetic detection means and the magnetic path forming means can be reduced without increasing the thickness.

Further, according to the present invention, the magnetic path forming means is provided with an extending portion extending in a direction of a magnetic flux penetrating through the gap in a portion other than the gap of the portion forming the magnetic path. According to the present invention, the cross-sectional area can be increased with the same projection area by the extending portion, so that the magnetic detection can be efficiently performed without increasing the outer shape. Further, the strength of the magnetic path forming means can be improved. Further, the extending portion is provided in a portion other than the gap portion, and can attract external magnetic flux generated in the same direction as the detected magnetic flux around the gap.
External magnetic flux hardly penetrates into the gap,
Current detection can be performed without the influence of external magnetic flux.

[0015]

FIG. 1 is a perspective view of an embodiment of the present invention. FIG. 2 is a plan view of one embodiment of the present invention, and FIG. 3 is a side view of one embodiment of the present invention. The current detection device 1 according to the present embodiment includes a magnetic path forming unit 2, a magnetic sensor 3, and a circuit board 4.

The magnetic path forming part 2 is composed of the first magnetic plate 5 and the second magnetic plate 5.
And the magnetic plate 6 is integrated by welding or the like. The first and second magnetic plates 5 and 6 are each formed by pressing a plate made of a magnetic material.
The connecting portion 9 is bent in the direction of the arrow Z so that the connecting portion 7 and the gap 8 parallel to each other are stepped in the direction of the arrow Z in the first magnetic plate 5. ing. The second magnetic plate 6 is connected in such a manner that the planar shape is U-shaped in the same manner as the first magnetic plate 5, and the connecting portion 10 and the gap portion 11 that are parallel to each other are stepped in the arrow Z direction. The part 12 is bent in the arrow Z direction.

The first magnetic plate 5 and the second magnetic plate 6 are joined by a joint 7 and a joint 10. The first magnetic plate 5 and the second magnetic plate 6 are connected to each other with the connecting portion 9 and the connecting portion 10 connected to each other while the connecting portion 9 is moved from the connecting portion 7 by an arrow Z.
The connecting portion 12 is bent in one direction, and
It is bent in two directions. For this reason, the gap portion 8 of the first magnetic plate 5 and the gap portion 11 of the second magnetic plate 6 overlap at the gap interval d to form the gap G.

The magnetic sensor 3 is disposed in the gap G. The magnetic sensor 3 is composed of a surface-mounted Hall element, and is surface-mounted on the circuit board 4. On the circuit board 4,
An amplification circuit for amplifying a detection signal detected by the magnetic sensor 3 is mounted. The magnetic sensor 3 is inserted into the gap G while being surface-mounted on the circuit board 4. That is, the magnetic sensor 3 and the circuit board 4 are inserted into the gap G such that the directions of the arrows X and Y are plane directions.

At this time, a portion where the gap portion 8 of the first magnetic plate 5 and the gap portion 11 of the second magnetic plate 6 overlap, that is, the area S1 of the gap G is larger than the area S2 of the magnetic sensor 3. Set to the area. Next, the operation of the current detection device 1 will be described. A cable 13 through which a current to be measured flows is provided through an opening 14 formed by the first and second magnetic plates 5 and 6. Cable 1
When a current I flows through 3, a magnetic field is generated in the direction of arrow A on the circumference centered on the cable 13 according to the right-hand screw rule of ampere. At this time, the magnitude of the magnetic field is proportional to the magnitude of the current I.

The magnetic field generated by passing the current I through the cable 13 causes a magnetic flux to flow in the magnetic path forming portion 2 as indicated by C, D, E, and F. At this time, the magnetic flux penetrates the magnetic sensor 2 through the gap G of the magnetic path forming portion 2. The magnetic sensor 2 outputs a detection signal according to the magnetic flux flowing through the gap G. The detection signal output from the magnetic sensor 2 is amplified by an amplifier circuit formed on the circuit board 4. At this time, the detection signal has a level corresponding to the current I flowing through the cable 13. Thus, the current detection device 1 can detect the current I flowing through the cable 13 in a non-contact manner.

As described above, according to the present embodiment, the magnetic path forming section 2, the magnetic sensor 3, and the circuit board 4 are arranged in parallel to the planes in the directions of the arrows X and Y, so that the thickness can be reduced. Also,
The portion where the gap 8 of the first magnetic plate 5 and the gap 11 of the second magnetic plate 6 overlap, that is, the area S1 of the actual gap is larger than the area S2 of the magnetic sensor 3. Even if there is an error in the positional relationship between the magnetic sensor 3 and the circuit board 4 and the positional relationship between the circuit board 4 and the magnetic path forming unit 2, the magnetic sensor 3 can be reliably connected to the actual gap. Since the magnetic sensor 3 can be arranged within the area S1 of the portion, the positioning of the magnetic sensor 3 can be easily performed.

In order to allow the magnetic flux to efficiently flow through the magnetic path forming section 2, the sectional area of the magnetic path forming section 2 may be increased. The periphery of the second magnetic plate may be bent.
FIG. 4 shows a perspective view of another embodiment of the present invention. In the figure, the same components as those of FIG.

The current detecting device 100 of this embodiment is different from FIG. 1 in the shapes of the first and second magnetic plates 102 and 103 constituting the magnetic path forming portion 101. In the first magnetic plate 102 of the present embodiment, a bent portion 104 is formed on the outer peripheral edge of the first magnetic plate 102 by bending in the direction of arrow Z1 by pressing or the like. Further, the second magnetic plate 103 has a bent portion 105 which is bent integrally by pressing or the like in the direction of arrow Z2 on the outer peripheral edge thereof.

The bent portions 104 and 105 are notched in the gap G, and have a shape in which the magnetic flux concentrates in the gap G. According to this embodiment, the first magnetic plate 102
By forming the bent portions 104 and 105 on the second magnetic plate 103, the cross-sectional area of the magnetic path forming portion 101 increases, so that the magnetic flux flowing through the magnetic path forming portion 101 can be increased.
In the gap G, the bent portions 104 and 105 are notched, and the magnetic flux is concentrated.
The magnetic flux can be efficiently supplied to the gap G according to the current I flowing through the cable 13 and can be detected by the magnetic sensor 3.

Further, according to the present embodiment, the bent portion 104 is formed in the direction of arrow Z as shown in FIG. The direction of the arrow Z is the direction of the magnetic flux of the detection magnetic field flowing through the gap G. Therefore, when there is a magnetic flux due to an external magnetic field due to terrestrial magnetism or a motor in the direction of arrow Z, the external magnetic flux is attracted to the bent portion 104 which is a magnetic material. FIG. 5 is an operation explanatory view of another embodiment of the present invention.

Since the bent portions 104 and 105 are notched in the gap G as shown in FIG. 5, the magnetic flux flowing in the arrow Z direction around the gap G as shown in FIG. It will be drawn to the bending parts 104 and 105. Therefore, the magnetic path forming portion 10 is provided in the gap G.
Since the magnetic flux component flowing in accordance with the current I is concentrated on the current sensor 1, the current can be detected without being affected by an external magnetic field.

In this embodiment, the bent portions 104, 10
Although 5 is provided on the outer circumference side, it may be provided on the inner circumference side, or may be provided on both the inner and outer circumference sides. Further, in the present embodiment, the magnetic path forming portion 101 is formed of a magnetic plate, but it is needless to say that the magnetic path forming portion 101 may be formed of a bar or the like.

[0028]

As described above, according to the present invention, the gap is formed in parallel with the arrangement surface of the magnetic path forming means.
Since the magnetism detecting means can be arranged in parallel with the arrangement surface of the magnetic path forming means, it is possible to reduce the thickness, and by extending the surface in a direction parallel to the arrangement surface direction of the magnetic path forming means,
Since the area of the gap can be increased, the positioning accuracy between the magnetic detecting means and the magnetic path forming means can be loosened without increasing the thickness, so that the assembling can be easily performed.

Further, according to the present invention, the magnetic path forming means is made of a plate material, and thus has the advantage that the thickness can be reduced. Further, according to the present invention, by the extension portion,
Since the cross-sectional area can be increased with the same projection area, it is possible to efficiently perform magnetic detection without increasing the outer shape, and the strength of the magnetic path forming means can be improved. The external magnetic flux generated in the same direction as the detected magnetic flux around the gap can be attracted, so that the external magnetic flux does not easily enter the gap, so that the current can be detected without the influence of the external magnetic flux Features such as

[Brief description of the drawings]

FIG. 1 is a perspective view of one embodiment of the present invention.

FIG. 2 is a plan view of one embodiment of the present invention.

FIG. 3 is a side view of one embodiment of the present invention.

FIG. 4 is a perspective view of another embodiment of the present invention.

FIG. 5 is an operation explanatory view of another embodiment of the present invention.

FIG. 6 is a perspective view of a conventional example.

FIG. 7 is a diagram illustrating an operation of an example of the related art.

FIG. 8 is a diagram showing a state where a magnetic flux passes through a gap.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1,100 Current detection device 2,101 Magnetic path formation part 3 Magnetic detection part 4 Circuit board 5,102 First magnetic body plate 6,103 Second magnetic body plate 7,10 Coupling part 8,11 Gap part 9, 12 connecting part 13 cable 14 opening 104, 105 bending part G gap

Claims (3)

[Claims] 1. A current detection device for detecting a current by detecting a magnetic field generated around the current by the current, wherein the current detection device is arranged around the current and serves as a magnetic path of a magnetic flux generated according to the current. Magnetic path forming means having a gap formed so that the magnetic flux penetrates in a direction substantially perpendicular to the direction of the magnetic flux; and magnetic detecting means disposed in the gap and detecting a magnetic flux flowing in the gap. Current detector. 2. The current detecting device according to claim 1, wherein said magnetic path forming means overlaps both ends of the magnetic material so that a gap is formed in the overlapping portion. 3. The magnetic path forming means has an extending portion extending in a direction of a magnetic flux penetrating through the gap in a portion of the portion forming the magnetic path except for the gap. The current detection device according to claim 1.