JP5828221B2 - Manufacturing method of current sensor - Google Patents

Description

The present invention relates to a method for manufacturing a closed-loop current sensor having a secondary coil.

  As a conventional current sensor, a magneto-sensitive element is arranged in a gap provided in a part of an annular magnetic core around which a secondary coil is wound, and the gap is detected by a detected current flowing through a primary conductor passing through the annular magnetic core. The magnetic field generated in the sensor is detected by a magneto-sensitive element, and a compensation current is passed through the secondary coil so that the magnetic field in the gap is always zero. By measuring this compensation current, an output proportional to the detected current is obtained. There is a closed loop current sensor configured as described above. (For example, see Patent Document 1)

JP 2008-506944 A

In the current sensor disclosed in Patent Document 1, one side of each of two U-shaped plate-like magnetic cores manufactured by pressing is inserted from both sides of a central hole of a bobbin around which a secondary coil is wound. In addition to the overlapping, a gap portion having a wide interval is provided to dispose the magnetosensitive element in part. The other side of each of the two cores is arranged so as to overlap outside the bobbin, and a closed magnetic circuit is formed by combining the two cores.
The magnetosensitive element is mounted on the circuit board, and the magnetosensitive element is arranged in the core gap portion with the bobbin and the circuit board integrally fixed by soldering, and these are integrally formed with the primary conductor. The primary conductor is housed in the resin case so as to penetrate the core, and the position is fixed by the resin cover.

In the current sensor configured as described above, since the core is composed of only two pressed parts, it is less expensive than conventional wound cores and press-laminated cores, and the step of combining a secondary coil with the core However, there is an advantage that it is easy and easy to make because only two cores are inserted from both sides of the bobbin.
However, there are problems that two types of press dies are required because the shapes of the two cores are different, and that the number of bending portions of the core is large and the bending is deep, so that the press process is increased and the die costs and processing costs are increased.

  In addition, after inserting the core and bobbin into the case, another part such as a cover is required to fix the position of the core and the bobbin, and there is a problem that the number of parts increases and the cost increases.

  An object of the present invention is to provide a closed loop current sensor that is easy to assemble, has a small number of parts, and is low in cost.

A core provided with a gap in a part of a closed magnetic path, a magnetosensitive element arranged in the gap, a bobbin in which a secondary coil is wound and the core passes through the central hole, a magnetosensitive element, and a peripheral circuit are mounted. In a closed loop type current sensor comprising a circuit board and a primary conductor disposed so as to penetrate the core, the core is substantially U-shaped, and each of the two sides is offset in the plate thickness direction and has the same shape. After the bobbin is inserted into the case, the two substantially U-shaped cores are inserted from the core insertion holes provided on both sides of the case, respectively. Each side is passed through the central hole of the bobbin, and the short side is inserted into a core guide groove provided in the case to form a closed magnetic circuit in which the gap is formed, and at the same time, the bobbin and the case are fixed. .

According to the current sensor manufacturing method of the present invention, two substantially U-shaped cores having the same shape are respectively inserted from the core insertion holes provided on both side surfaces of the case, thereby forming a closed magnetic circuit in which the gap is formed. Because the bobbin and case are fixed, no fixing parts are required, and the two substantially U-shaped cores have the same shape, so only one press die is required, and the current sensor is inexpensive. Can be obtained.

It is a disassembled perspective view which shows the current sensor in embodiment of this invention. It is side surface sectional drawing of the current sensor in embodiment of this invention. It is front sectional drawing of the current sensor in embodiment of this invention. It is a core single item side view of the current sensor in an embodiment of the present invention. It is a perspective view which shows the core combination state of the current sensor in embodiment of this invention. It is a perspective view which shows the combination state of the core and bobbin of the current sensor in embodiment of this invention.

Hereinafter, an embodiment of a current sensor according to the manufacturing method of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the part which is the same in each figure, and the description is abbreviate | omitted.

1, 2 a, and 2 b, a secondary coil 2 is wound around the bobbin 1, and both ends of the secondary coil 2 are connected to pins 3 and 4 erected on the bobbin 1. A terminal pin 5 is fixed to the bobbin 1. The bobbin 1 is inserted from the lower part of the case 7 integrally formed with the U-shaped primary conductor 6 and is arranged below the primary conductor 6, and is inserted from the core insertion holes 8 provided on both side surfaces of the case 7. The long sides 11 and 12 of the substantially U-shaped cores 9 and 10 having the same shape are passed through the central hole 13 of the bobbin 1, and the short sides 14 and 15 are inserted into the core guide groove 16 provided on the upper portion of the primary conductor 6. Thus, the short sides 14 and 15 are arranged so as to be opposed to each other by forming a constant gap 17, whereby the primary conductor 6 forms a closed magnetic path penetrating the inside and the bobbin 1 is fixed to the case 7.

  The circuit board 19 on which the magnetosensitive element 18 is mounted is inserted from the upper opening of the case 7, and the magnetosensitive element 18 is disposed in the gap 17. After the circuit board 19 is inserted into the case 7, the pins 3 and 4 to which the secondary coil 2 is connected and the terminal pins 5 are soldered and connected to the circuit board 19.

The cover 20 that is hinged together with the case 7 is fixedly fitted into the upper portion of the case 7 after the electrical adjustment of the circuit board 19 is completed.

FIG. 3 a is a single side view of the core 9. Since the core 9 and the core 10 have the same shape, description will be made using the symbol of the core 9. The long side 11 and the short side 14 of the core 9 are arranged offset in the plate thickness direction by the bending portion 21.
FIG. 3b shows a structure when two cores are combined with the cores facing each other. When the long sides 11 and 12 are brought into close contact with each other, a gap 17 is formed at a portion where the short sides 14 and 15 overlap.
FIG. 3 c shows the structure when the cores 9 and 10 are inserted into the bobbin 1, and the cores 9 and 10 are prevented from being pulled out after insertion by the core retaining claws 22 provided on the bobbin 1.

According to the current sensor according to the manufacturing method of the present invention, since the two substantially U-shaped cores 9 and 10 have the same shape, only one press die is required, and the shape is simple because there is only one bending portion. Costs and component costs can be reduced.

    Further, since the substantially U-shaped cores 9 and 10 also have a function of fixing the bobbin 1 and the case 7, a separate part for fixing the bobbin becomes unnecessary, and a low-cost current sensor is realized with a small number of parts. be able to.

1 bobbin, 2 secondary coil, 3 and 4 pins, 5 terminal pins, 6 primary conductor, 7 case, 8 core insertion hole, 9 and 10 core, 11 and 12 long side, 13 central hole, 14 and 15 short side, 16 Core guide groove, 17 Gap, 18 Magnetosensitive element, 19 Circuit board, 20 Cover, 21 Bending part, 22 Core retaining claw

Claims (1)

A core provided with a gap in a part of a closed magnetic path; a magnetosensitive element disposed in the gap; a bobbin in which a secondary coil is wound and the core passes through a central hole; the magnetosensitive element and a peripheral circuit; In a manufacturing method of a closed loop type current sensor comprising a mounted circuit board, a primary conductor disposed so as to penetrate the core, and a resin case integrally formed with the primary conductor, the core is substantially And is formed of two plate-like cores (9) and (10) having the same shape and arranged with their two sides offset in the thickness direction, and the bobbin (1) is connected to the case. After the insertion into (7), the two cores (9), (10) are inserted in opposite directions from the core insertion holes (8) provided on both side surfaces of the case (7), respectively. Long sides (11) and (12) are bobbins ( ) Through the central hole (13), and the short sides (14) and (15) are inserted into the core guide groove (16) provided in the case (7) to form the closed magnetic field in which the gap (17) is formed. at the same time constitute the road, the bobbin (1) and case (7) is black over Zudorupu type current method for producing a sensor, characterized in that the arrangement is secured.

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