JP3543309B2 - Current detector - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrical change detecting device using a Hall element, a magnetoresistive element, or the like, and particularly to a current detecting device that performs current detection.
[0002]
[Prior art]
As shown in FIG. 5, a conventional current detecting device includes a silicon steel body 1 having a substantially U-shape, a coil 2 wound around the silicon steel body 1, and a magnet provided in a gap 4 of the silicon steel body 1. And a Hall IC 3 containing a Hall element as a conversion element. The coil 2 is connected to, for example, a motor, a lamp, a battery, and the like used for a power steering, a power window, and the like, which are automotive electrical components. When a current flows through the coil 2, a magnetic flux is generated in the silicon steel body 1 according to the magnitude of the current, and the Hall IC 3 that detects a magnetic flux also generated in the gap 4 generates an output according to the magnetic flux. . Since the magnetic flux is proportional to the current, the magnitude of the current can be detected.
[0003]
[Problems to be solved by the invention]
By the way, in the conventional current detecting device shown in FIG. 5, the coil 2 and the silicon steel body 1 are used, and since the coil 2 is wound around the silicon steel body 1, there is a disadvantage that the current detecting device itself becomes large. is there. In addition, in order to correct the current detection sensitivity in which variations occur for each detection device, the current detection sensitivity is adjusted by changing the number of turns of the coil, the size of the gap 4, the position of the Hall IC 3, and the like. Was difficult and sufficient accuracy could not be obtained.
[0004]
Therefore, an object of the present invention is to provide a current detection device that is compact and can easily adjust the current detection sensitivity.
[0005]
[Means for Solving the Problems]
The current detecting device according to the present invention for achieving the above object has a U-shape formed by a connecting portion (5c) surrounding the opening (7) and a pair of lead-out portions (5d) connected to the connecting portion (5c). The conductive plate (5) formed on the conductive plate (5) is disposed so as to cover at least a part of the opening (7) and face one main surface (5a) and the other main surface (5b) of the conductive plate (5). And a pair of magnetic plates (6) through which a magnetic flux generated when a current flows through the conductive plate (5) and the magnetic plate (6) in the opening (7) of the conductive plate (5) are disposed. A magneto-electric conversion element (3). The lead-out portion (5d) of the conductive plate (5) is led out of the magnetic plate (6) to form the electrical connection terminals (A, B). Since the conductive plate (5) and the magnetic plate (6) are both formed in a plate shape to form a laminated structure, the current detection device becomes compact. Also, a trimming portion (8) is formed on the magnetic plate (6) in the opening (7) so as to face the magnetoelectric conversion element (3), and the amount of magnetic flux linked to the magnetoelectric conversion element (3) is changed. Thus, the current detection sensitivity can be adjusted accurately and easily. The magnetic plate (6) may be a silicon steel plate. Further, as described in claim 3, the magnetoelectric conversion element can be a Hall IC.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a current detection device according to the present invention will be described with reference to FIGS. However, in FIG. 1, substantially the same parts as those shown in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIGS. 1 and 2, the current detection device according to the present embodiment includes a connecting portion 5 c surrounding the opening 7 formed inside and a pair of lead-out portions 5 d connected to the connecting portion 5 c. A copper plate 5 serving as a conductive plate formed in a shape, and at least a part of the opening 7 is arranged so as to be opposed to one main surface 5a and the other main surface 5b of the copper plate 5, and a current flows through the copper plate 5. A silicon steel plate 6 as a pair of magnetic plates through which a magnetic flux generated sometimes passes, and a Hall IC 3 as a magnetoelectric conversion element arranged between the silicon steel plates 6 in the opening 7 of the copper plate 5 are provided. The lead-out portion 5d of the conductive plate 5 is drawn out of the magnetic plate 6 and forms the electrical connection terminals A and B. The pair of silicon steel plates 6 is bonded to one main surface 5a and the other main surface 5b of the copper plate 5 with an epoxy adhesive so as to cover a part of the opening 7. The Hall IC 3 is inserted into a gap 9 formed between the pair of silicon steel plates 6 in the opening 7 and bonded with a silicon-based adhesive to prevent thermal distortion. The external electrical connection terminals A and B are connected to a motor, a lamp, a battery, and the like used in an automobile.
[0007]
Next, the operation of the current detection device will be described. When a current flows between A and B of the copper plate 5, a magnetic flux is generated in the two silicon steel plates 6, and a magnetic flux is also generated between the silicon steel plates in the opening 7. In the opening 7, this magnetic flux flows from one main surface 5a of the copper plate 5 to the other main surface 5b or the other main surface 5b to the one main surface 5a, that is, from the front surface of the paper surface to the back surface or the back surface. A magnetic flux directed toward the surface is generated. This magnetic flux is detected by a Hall element incorporated in the Hall IC 3, and after signal processing, a detection signal is output from the output terminal b of the Hall IC 3. The terminals a and c of the Hall IC 3 are power terminals. The adjustment of the current detection sensitivity is performed by trimming the silicon steel plate 6, and 8 is a trimming portion removed by trimming.
[0008]
In the present embodiment, the current detection device can be made compact because a conductive plate (copper plate) 5 and a magnetic plate (silicon steel plate) 6 which are both formed in a plate shape are used without using a coil. Further, by forming a trimming portion 8 on the magnetic plate 6 in the opening 7 so as to face the magneto-electric conversion element 3, the amount of magnetic flux linked to the magneto-electric conversion element is changed, and current detection can be performed with high accuracy and easily. Sensitivity can be adjusted.
[0009]
Embodiments of the present invention are not limited to the above embodiments, and various modifications are possible. For example, the shape of the opening 7 of the copper plate 5 as a conductive plate may be convex as shown in FIG. If it is convex, accurate positioning is possible. The shape of the copper plate 5 and the opening 7 can take various shapes. The magnetic plate 6 is not limited to a silicon steel plate, but may be made of permalloy or another magnetic material. Further, as shown in FIG. 4, the magnetic plate 6 may have a structure in which two magnetic plates are integrated by a connecting portion 6a. Further, the magnetoelectric conversion element is not limited to a Hall element or an element using a Hall element, but may be a magnetoresistance element or an element using a magnetoresistance element. Further, the trimming portion 8 may be formed only on one side of the magnetic plate. Note that laser trimming, blast trimming, or the like can be used as a trimming method.
[0010]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, a conductor and a magnetic body can be made into plate shape, and a current detection apparatus can be comprised very small as a laminated structure. Further, by trimming the magnetic plate, the amount of magnetic flux linked to the magnetoelectric conversion element can be changed, and the sensitivity of the magnetoelectric conversion element can be easily and accurately adjusted.
[Brief description of the drawings]
FIG. 1 is a front view and a side view of a current detecting device according to an embodiment of the present invention. FIG. 2 (a) is a front view of a conductive plate, and FIG. 2 (b) is a front view of a magnetic plate. FIG. 4 is a front view showing a modified embodiment of a magnetic plate. FIG. 5 is a front view showing a modified embodiment of a magnetic plate. FIG. 5 is a perspective view showing a conventional current detecting device.
3 ・ ・ Magneto-electric conversion element, 5 ・ ・ Conduction plate, 6 ・ ・ Magnetic plate,

Claims (3)

A U-shaped conductive plate formed by a connecting part surrounding the opening and a pair of lead-out parts connected to the connecting part; and one main surface of the conductive plate covering at least a part of the opening A pair of magnetic plates disposed opposite to the other main surface and through which a magnetic flux generated when a current flows through the conductive plate passes, and a magnetoelectric device disposed between the magnetic plates in the opening of the conductive plate. With a conversion element,
The lead portion of the conductive plate is led out of the magnetic plate to form an electrical connection terminal,
A current detecting device, wherein a trimming portion is formed on the magnetic plate in the opening so as to face the magnetoelectric conversion element, and the amount of magnetic flux linked to the magnetoelectric conversion element is changed. The current detection device according to claim 1, wherein the magnetic plate is a silicon steel plate. 3. The current detection device according to claim 1, wherein the magnetoelectric conversion element is a Hall IC.

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