JP2000284031A - Magnetic circuit for current-to-magnetic flux conversion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily perform the winding operation of a current wire to a magnetic circuit for current-to-magnetic flux conversion and to reduce the number of kinds of components. SOLUTION: This magnetic circuit for current-to-magnetic flux conversion is formed of a three-legged yoke constituted by bending a magnetic plate material, and the magnetic circuit is provided with a gap in which a magnetic sensor is inserted into its central leg part. The tripod yoke 1 is formed in such a way that a pair of divided yokes 2, 2' in the same shape are assembled alternately. Every divided yoke has a shape in which window parts 5, 5' are opened in a state that a current wire can be inserted. In a state that the pair of divided yokes are assembled, central leg parts 7, 8 in the pair of divided yokes are situated so as to make a space, and the gap 9 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Hall element used for measuring current, voltage, electric power (quantity), and the like.
The present invention relates to an improvement of a magnetic circuit for current-flux conversion for applying a magnetic flux to a magnetic sensor such as an MR element and a thin film flux gate.

[0002]

2. Description of the Related Art A magnetic circuit (iron core) called a yoke is required to generate a magnetic flux proportional to a current to be applied to a magnetic sensor. Conventionally, as a magnetic circuit, there are a cut-core type shown in FIG. 5A and a tripod type shown in FIG. 5B. For the cut core type, the yoke 2
A current wire 22 is wound around 1 (iron core), and a magnetic flux is generated in the yoke 21 by a current flowing through the current wire 22. Yoke 21
Is provided with a gap 23, and a magnetic sensor 24 is inserted into the gap 23. A magnetic field proportional to the current of the current line 22 is generated in the gap 23, and the magnetic field causes the magnetic sensor 24 to output an electric signal proportional to the magnitude of the magnetic field.
Similarly, in the case of the tripod type, the current wire 26 is connected to the yoke 25 (iron core).
Is wound, and the yoke 25
Generates magnetic flux. A gap 27 is provided in the yoke 25, and a magnetic sensor 28 is inserted into the gap 27.

[0003]

In a tripod type magnetic circuit, it is assumed that the circuit is made of a magnetic plate as shown in FIG. In this case, it is necessary to generate a magnetic flux in the yoke 25 by winding the current wire 26 somewhere on the yoke 25, for example, around the center leg. Considering this, if the yoke is formed integrally without being divided, the current line 26
Winding work is difficult.

A case is considered in which a magnetic sensor is inserted into a gap 27 formed in the central leg of the yoke 25. If the magnetic flux density distribution in the gap 27 is not uniform,
The amount of magnetic flux applied to the magnetic sensor differs depending on the position of the inserted magnetic sensor, and the output of the magnetic sensor is not constant. Considering this, if the magnetic flux density distribution in the gap 27 is uniform, the output from the magnetic sensor will not depend on the insertion position accuracy of the magnetic sensor.
It is very advantageous in manufacturing. However, FIG.
In the case of a magnetic circuit composed of a magnetic plate as shown in FIG. 7B, the uniform magnetic flux density distribution in the gap 27 is shown in FIG. 7C by the thickness d of the magnetic plate constituting the yoke 25. Therefore, the width cannot be set regardless of the thickness of the magnetic plate material. (Object of the Invention) A first object of the present invention is to provide a magnetic circuit for current-flux conversion which facilitates winding work of a current line and can reduce the number of types of parts.

A second object of the present invention is to facilitate the operation of winding the current wire and reduce the number of types of parts, and at the same time, to make the range of uniformity of the magnetic flux density distribution of the gap irrespective of the thickness of the magnetic plate material. It is to provide a magnetic circuit for current-flux conversion that can be set.

[0006]

In order to achieve the first object, the present invention according to the first aspect comprises a tripod-type yoke formed by bending a magnetic plate material, and a magnetic sensor is provided at a central leg. In the magnetic circuit for current-flux conversion provided with a gap for inserting the same, the tripod-type yoke is formed by alternately assembling a pair of split yokes of the same shape, and each split yoke is formed in a window portion. Are open to allow insertion of current lines, and in the assembled state of the pair of split yokes, the center legs of the pair of split yokes are spaced apart to form a gap. It is characterized by the following.

In order to achieve the second object,
According to a second aspect of the present invention, in the magnetic circuit for current-flux conversion according to the first aspect, each of the divided yokes has a shape in which the central leg is displaced from the center in the left-right direction. In the assembled state of the divided yokes, a gap is formed by locating the side surfaces of the central legs of the pair of divided yokes so as to overlap each other with a space therebetween.

[0008]

FIG. 1 is a perspective view showing a magnetic circuit for current-flux conversion according to an embodiment of the present invention.
(A) shows only one of the divided yokes, (b) shows a state immediately before the completion of assembly, and (c) shows a state of completion of assembly.

The tripod-type yoke 1 is formed by assembling a pair of split yokes 2 and 2 'of the same shape alternately from the left and right. The split yoke 2 (2') is formed by bending a magnetic plate material by a press or the like. It is processed and formed into a shape as shown in FIG. This shape is such that the center leg components 3 (3 ′) and 4 (4 ′) constituting the center leg are shifted from the center of the tripod yoke 1 in the left-right direction, respectively.
Further, the window portion 5 is open to the outside through the space 6 between the central leg components 3 and 4.

When assembling the split yokes 2 and 2 ', the split yoke 2' is turned upside down so that the central leg components 3 and 4 'and the central leg components 4 and 3' are joined. Assemble staggered left and right. Thereby, as shown in FIG. 1 (c), the upper central leg 7 is formed by the central leg components 3 and 4 ', and the lower central leg 8 is formed by the central leg components 4 and 3'. Is done. The window portion into which the current wire coil is inserted is formed at positions 5 and 5 '. The central legs 7, 8 are positioned such that their side surfaces overlap with a gap therebetween, the gap forming a gap 9. This gap 9 is a space into which the magnetic sensor is inserted.

In the case of winding a current wire, as shown in FIG. 2, before assembling the divided yokes 2 and 2 ', the current line coil 10 formed separately in advance is divided into the divided yokes 2 and 2'.
Through the space 6 of (2 '), it is housed in the window portion 5 (5'), that is, around the center legs 7, 8, and then the divided yokes 2, 2 'are assembled. Thereby, the current wire coil 1
The operation of winding the zero-type tripod yoke 1 is greatly simplified. FIG. 2 shows the current wire coil 10 having one turn, but the same applies to a current wire coil having a plurality of turns. Since the divided yokes 2 and 2 'have the same shape, the types of components can be reduced.

The range in which the magnetic flux density distribution of the gap 9 is uniform is set by adjusting the overlapping range of the central leg portions 7 and 8. Has nothing to do. Therefore, by adjusting the length of the center leg constituent parts 3 (3 ′) and 4 (4 ′) according to the area of the magnetically sensitive part of the magnetic sensor inserted into the gap 9, the magnetic flux density distribution of the gap 9 is adjusted. A range with uniformity can be set irrespective of the thickness of the magnetic plate material, and the degree of freedom in design can be increased.

FIG. 3 is a perspective view showing a magnetic circuit for current-flux conversion according to another embodiment of the present invention. FIG. 3A shows only one of the divided yokes, and FIG. (C) shows the assembly completed state.

The tripod-type yoke 11 is formed by assembling a pair of split yokes 12, 12 'of the same shape alternately from above and below.
2 ') is formed by bending a magnetic plate material using a press machine or the like to form a shape as shown in FIG. In this shape, the center leg 15 (15 ') is folded to have a thickness twice that of the side legs 13 (13') and 14 (14 '), and the center leg 15 (15') is formed. ) Is located at a position shifted from the center of the tripod-type yoke 11 in the left-right direction.
Reference numeral 17 denotes a shape that is open in the vertical direction.

When assembling the split yokes 12, 12 ', the split yokes 12' are turned upside down and the side legs 13 and 1 'are assembled.
4 'and side legs 14 and 13' are staggered in the vertical direction so as to be joined. Thus, as shown in FIG. 3 (c), the upper central leg is formed by the central leg 15 and the lower central leg is formed by the central leg 15 '. The window portion into which the current wire coil is inserted is the window portion 1 of the split yokes 12, 12 '.
6, 17 are formed together. Central leg 15,1
5 ′ are positioned such that their sides overlap one another with a gap therebetween, the gap forming a gap 18. This gap 18 is a space into which the magnetic sensor is inserted.

When the current wire is wound, as shown in FIG. 4, before assembling the divided yokes 12, 12 ',
The current yoke coil 10 formed separately in advance is divided into divided yoke 1
2 (12 ') to the window portions 16, 17;
5,15 ', then split yokes 12,1'
Assemble 2 '. Thereby, the work of winding the current wire coil 10 around the tripod yoke 11 is greatly simplified.
Since the divided yokes 12, 12 'have the same shape, the types of parts can be reduced.

Further, by adjusting the length of the central leg portions 15 and 15 'in accordance with the area of the magnetically sensitive portion of the magnetic sensor inserted into the gap 18, a range in which the magnetic flux density distribution of the gap 18 is uniform can be obtained. Can be set irrespective of the thickness of the magnetic plate material, and the degree of freedom in design can be increased as in the embodiment shown in FIG.

In the case where the range where the magnetic flux density distribution of the gap is uniform may be small, that is, the center legs 7 and 8 may be used.
Alternatively, when the center legs 7 and 8 or 15 and 15 'are not shifted from the center in the left-right direction, the center legs 7 and 8 or the center legs 7 and 8 may be positioned at the center. Good.

[0019]

As described above, according to the first aspect of the present invention, a tripod-type yoke is formed by alternately assembling a pair of split yokes having the same shape, and each split yoke is formed in a window portion. Since the shape is open to the state in which the current line can be inserted, and in the assembled state of the pair of split yokes, the central legs of the pair of split yokes are spaced from each other to form a gap, The current wire winding operation is facilitated, and the types of components can be reduced.

According to the second aspect of the present invention, each of the divided yokes has a shape in which the center leg is shifted from the center in the left-right direction. Since the gap is formed by locating the sides of the center leg of the yoke so as to overlap with each other, the winding operation of the current wire is facilitated,
The number of types of parts can be reduced, and at the same time, a range in which the magnetic flux density distribution of the gap is uniform can be set regardless of the thickness of the magnetic plate material.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a magnetic circuit for current-flux conversion according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which a current wire coil is wound around the current-magnetic flux conversion magnetic circuit of FIG. 1;

FIG. 3 is a perspective view showing a magnetic circuit for current-flux conversion according to another embodiment of the present invention.

FIG. 4 is a perspective view showing a state in which a current wire coil is wound around the current-magnetic flux conversion magnetic circuit of FIG. 3;

FIG. 5 is a diagram showing a current converter using a conventional magnetic circuit.

FIG. 6 is a diagram showing a relationship between a conventional magnetic circuit and a current line.

FIG. 7 is a diagram showing a magnetic flux density distribution in a gap of a conventional tripod yoke.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tripod type yoke 2, 2 'Split yoke 3, 3', 4, 4 'Central leg constituent part 5 Window part 6 Space 7, 8 Central leg 9 Gap 10 Current wire coil 11 Tripod type yoke 12, 12' Split yoke 13, 13 ', 14, 14' side leg 15, 15 'central leg 16, 17 window portion 18 gap

Claims (2)

[Claims] 1. A magnetic circuit for current-flux conversion, comprising a tripod-type yoke formed by bending a magnetic plate material and having a gap for inserting a magnetic sensor into a central leg, wherein the tripod-type yoke is provided. Are formed by alternately assembling a pair of split yokes of the same shape, and each of the split yokes has a shape in which a window portion is open to a state where a current line can be inserted, and in an assembled state of the pair of split yokes, A magnetic circuit for current-flux conversion, wherein a gap is formed by the central legs of the pair of split yokes being spaced from each other. 2. The split yoke has a shape in which the central leg is displaced from the center in the left-right direction, and in a state where the pair of split yokes are assembled, a side surface of the central leg of the pair of split yokes. 2. The magnetic circuit for current-to-flux conversion according to claim 1, wherein a gap is formed by being positioned so as to overlap each other with a space therebetween.