JP2017062220A - Fixing tool and fixing method of measurement target current line, and current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current sensor capable of reducing an effect on a magnetoelectric transducer by a noise of electrostatic coupling generated with an abrupt change of a potential of a measurement target current line, and also reducing an effect on the magnetoelectric transducer through a core from the measurement target current line by the noise with the electrostatic coupling, thus enabling measurement with excellent accuracy.SOLUTION: A fixing tool 5 includes a combination of: a measurement target current line 1; a shield plate 2 having a cylindrical part 13 arranged so as to cover the measurement target current line; a terminal 3 capable of connecting the shield plate 2 so as to have the same potential as a ground pad on a circuit board; and a support medium 4 composed of an insulator and arranged between the measurement target current line 1 and the shield plate 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fixture for fixing a current wire to be measured, a method for fixing the current wire to be measured, and a current sensor including a current wire to be measured fixed to the fixture.

  Conventionally, a magneto-electric conversion element is covered with a leaf spring-like member connected to a ground pad on a circuit board constituting a current sensor to serve as a shield means. Moreover, this is installed in the gap portion of the core, and the plate spring-like member presses the core so that the potential of the core can be dropped to the ground. (For example, refer to Patent Document 1).

  Further, the shield plate is configured to cover the magnetoelectric conversion element with a shield plate connected to a ground pad on a circuit board constituting the current sensor, and further cover other electronic components on the board. (For example, refer to Patent Document 2).

  Further, the circuit board constituting the current sensor is arranged in parallel with the current through path, and a shield plate such as a copper material is arranged between the circuit board and the core, and the ground pad, the shield board and the core on the circuit board are arranged. It is configured to be electrically connected. (For example, refer to Patent Document 3).

  Furthermore, a shield plate made of a metal plate is installed between the circuit board and the core, the shield board and the core are brought into contact, and the shield board is connected to a ground pad on the circuit board. (For example, refer to Patent Document 4).

JP 2009-300123 A JP 2005-24519 A JP 2009-121864 A JP-A-8-194015

However, the current sensor disclosed in Patent Document 1 covers the magnetoelectric conversion element with a leaf spring-like member connected to a ground pad on a circuit board, and presses the gap of the core with the aforementioned leaf spring-like member. In order to drop the potential of the core to the ground, it is necessary to make the core gap wider than the one in which only the magnetoelectric conversion element is installed in the core gap, thereby the magnetoelectric conversion element installed in the core gap. There is a risk of lack of sensitivity.
Further, since the core gap is widened, the magnetoelectric conversion element installed in the gap may be easily affected by an external magnetic field.
Furthermore, since the shield plate and the magnetoelectric conversion element are installed in the gap of the core, the distance between the shield plate and the lead terminal of the magnetoelectric conversion element becomes narrow, and there is a risk of electrical failure due to contact.

In addition, the current sensor disclosed in Patent Document 2 has a shield plate configuration that covers a magnetoelectric conversion element with a shield plate connected to a ground pad on a circuit board and further covers other electronic components on the board. It has become. If the magnetoelectric conversion element covered with this shield plate is installed in the core gap to form a current sensor, it is necessary to make the core gap wider than that in which only the magnetoelectric conversion element is installed in the core gap. For this reason, there is a possibility that the sensitivity of the magnetoelectric conversion element installed in the gap of the core is insufficient. Further, since the core gap is widened, the magnetoelectric conversion element installed in the gap may be easily affected by an external magnetic field.
Furthermore, since the shield plate and the magnetoelectric conversion element are installed in the gap of the core, the distance between the shield plate and the lead terminal of the magnetoelectric conversion element becomes narrow, and there is a risk of electrical failure due to contact.

  Furthermore, in the current sensor disclosed in Patent Document 3, a shield plate made of copper or the like is disposed between the circuit board and the core. However, since the magnetoelectric conversion element is disposed outside the shield, the shielding effect is achieved. There is a possibility that the measurement accuracy of the current is deteriorated due to the shortage of.

In addition, the current sensor disclosed in Patent Document 4 installs electrostatic coupling noise generated when the electric potential of the coil wire, which is the current wire to be measured, changes abruptly, between the coil wire and the circuit board. However, there is a possibility that the shielding effect is insufficient for the noise that affects the coil wire through the core.
Moreover, since the magnetoelectric conversion element of the current sensor disclosed in Patent Document 4 is not shielded, the noise reduction effect may be insufficient.

  The present invention has been made in view of such circumstances, and reduces noise caused by electrostatic coupling caused by a sudden change in the potential of the current line to be measured. Provided is a current sensor that has a fixture for a current wire to be measured that can reduce noise, can install a magnetoelectric conversion element without widening the gap of the core, and can measure with excellent accuracy For the purpose.

  In order to achieve this object, the present invention has a shield plate mainly composed of copper or a copper alloy installed so as to cover the current line to be measured, and the shield plate is the same as the ground pad on the circuit board. The present invention also provides a fixing device for a current wire to be measured, which has a terminal that can be connected to have a potential, and further includes a support member made of an insulator between the current wire to be measured and a shield plate.

  The fixture having this configuration has an insulating support formed of resin, and since the measured current line is provided inside the support, the measured current line is in electrical contact with other components. Can be prevented. Further, the support can be formed as a separate part from the current wire to be measured, but the assembly process can be simplified because the support and the current wire to be measured can be integrally formed.

  In addition, the fixture has a shield plate on the outside of the support with the current wire to be measured so as to cover the support, but it does not cover all of the support but covers a part to simplify the assembly process. It can also be converted.

  Furthermore, the shield plate has a terminal that can be connected to the same potential as the ground pad on the circuit board. By fixing the potential of the shield plate to the ground, the potential of the measured current changes rapidly. It is possible to reduce the influence of the generated electrostatic coupling noise on other electronic components.

  Moreover, the present invention also provides a current sensor provided with the fixture according to the present invention described above. The current sensor having this configuration reduces the influence of the electrostatic coupling noise caused by the sudden change in the potential of the current line to be measured on the magnetoelectric transducer, and the aforementioned electrostatic coupling noise. Can also affect the magnetoelectric conversion element from the measured current line through the core. Further, since it is not necessary to cover the magnetoelectric conversion element with a shield, it is possible to provide a current sensor that can be installed in the core gap without widening the core gap and can be measured with excellent accuracy.

  According to the present invention, the shield plate mainly composed of copper or copper alloy is provided so as to cover the current wire to be measured, and the shield plate described above has the same potential as the ground pad on the circuit board. It has a terminal that can be connected to the device, and also has a fixture for the current wire to be measured that has a support made of an insulator between the current wire to be measured and the shield plate, and can be measured with excellent accuracy. Current sensor can be provided.

It is a perspective view which shows the fixing tool concerning Embodiment 1 of this invention. It is a disassembled perspective view which shows the fixing tool shown in FIG. It is sectional drawing along the VI-VI line of the fixing tool shown in FIG. It is a disassembled perspective view of a current sensor provided with the fixture shown in FIG. It is a perspective view which shows the fixing tool concerning Embodiment 2 of this invention. FIG. 6 is a cross-sectional view taken along line VI-VI of the fixture shown in FIG. 5. It is a perspective view which shows the fixing tool concerning Embodiment 3 of this invention.

  Next, a fixture according to an embodiment of the present invention and a current sensor including the fixture will be described with reference to the drawings. In addition, embodiment described below is the illustration for demonstrating this invention, and this invention is not limited only to these embodiment. Therefore, the present invention can be implemented in various forms without departing from the gist thereof.

(Embodiment 1)
1 is a perspective view showing a fixture according to Embodiment 1 of the present invention, FIG. 2 is an exploded perspective view showing the fixture shown in FIG. 1, and FIG. 3 is a VI-VI line of the fixture shown in FIG. FIG. 4 is a perspective view showing a current sensor including the fixture shown in FIG. 1.
In the drawings, for easy understanding, the thickness, size, enlargement / reduction ratio, etc. of each member are not matched with the actual ones.

  As shown in FIGS. 1, 2, and 3, the fixture 5 according to the first embodiment includes a shield plate 2 having a measured current line 1 and a cylindrical portion 13 that is installed so as to cover the measured current line. A terminal 3 that can connect the shield plate 2 to the same potential as the ground pad on the circuit board, and a support that is installed between the current wire 1 to be measured and the shield plate 2 and is made of an insulator. The body 4 is combined.

  The current wire 1 to be measured is obtained by bending a pattern obtained by punching a plate mainly composed of copper or a copper alloy, and is connected to a through hole of a substrate of an external circuit by soldering. A plurality of terminals 3 are provided at both ends of the measurement current line 1.

  The shield plate 2 is obtained by bending one pattern obtained by punching a plate material mainly composed of copper or a copper alloy, and the shield plate 2 can be connected to have the same potential as the ground pad on the circuit board. The terminal 3 is composed of one or more terminals. In addition, as shown in FIG. 2, the shield plate 2 has a tubular portion 13 bent into a tubular shape so as to cover the current line 1 to be measured by bending one pattern, When the wire 1 is inserted into the shield plate 2 and installed, only the one end portion of the current wire 1 to be measured is bent in advance, and the current wire 1 to the tube portion 13 of the shield plate 2 remains straight. Can be inserted, and then the one end portion of the linear current wire 1 to be measured can be bent to form the fixture 5.

  The support 4 is made of an insulator formed of resin, and electrically insulates the current wire 1 to be measured and the shield plate 2 from each other. The support 4 can be molded and combined with the current wire 1 to be measured as a separate part, but the assembly process can be simplified because the support 4 and the current wire 1 to be measured can be integrally formed. It can also be converted.

  As shown in FIG. 4, the current sensor 14 according to the first embodiment includes the fixture 5 shown in FIG. 1, and a core 6 that collects a magnetic field generated by a current flowing through the current wire 1 to be measured. And a magnetoelectric conversion element 7 for converting the collected magnetic field into an electric signal. In addition, the case of the current sensor 14 that fixes the fixture 5, the core 6, and the magnetoelectric conversion element 7 is omitted.

  The core 6 can be made of a material having high magnetic permeability, such as ferrite, silicon steel plate, permalloy, supermalloy, amorphous, and nanocrystalline alloy. Further, the core 6 can be fixed in contact with the shield plate 2 of the fixture 5. Further, the core 6 and the measured current line 1 can be sufficiently insulated by the support 4 of the fixture 5.

  For example, the magnetoelectric conversion element 7 may include a magnetic sensor such as a Hall element, MR, GMR, or TMR, and a semiconductor circuit that drives the magnetic sensor described above and adjusts an electric signal obtained from the magnetic sensor. it can.

(Embodiment 2)
Next, Embodiment 2 according to the present invention will be described with reference to the drawings. 5 is a perspective view showing a fixture according to Embodiment 2 of the present invention, and FIG. 6 is a cross-sectional view (YZ plane) taken along line VI-VI of the fixture shown in FIG.
In the second embodiment, detailed description of the same configuration and the same process as in the first embodiment is omitted.

  The main difference between the fixture 8 according to the second embodiment and the fixture 5 according to the first embodiment is the shapes of the shield plate 9 and the shield plate 2 constituting the fixture.

  Since the shield plate 9 has a substantially U-shaped cross section, the current line 1 to be measured and the support 4 can be installed from the open side of the substantially U-shape of the shield plate 9 so that the assembly process can be simplified. .

(Embodiment 3)
Next, Embodiment 3 according to the present invention will be described with reference to the drawings. FIG. 7 is a perspective view showing a fixture according to Embodiment 3 of the present invention.
In the third embodiment, the detailed description of the same configuration and the same process as in the first embodiment is also omitted.

  The main difference between the fixture 10 according to the third embodiment and the fixture 5 according to the first embodiment is the shapes of the measured current line 11 and the measured current line 1 constituting the fixture.

  The current line 11 to be measured is obtained by bending one or more conductors obtained by cutting a bar whose main component is copper or a copper alloy. For example, as shown in FIG. It is also possible to flow current through the line 11 at once, and it is also possible to adjust the current to be measured by flowing current by changing the connection pattern of the three current lines 11 to be measured. Moreover, the support body 12 can also be provided so that the mutual to-be-measured current line 11 may not contact. Further, the support 12 is made of an insulator molded from resin.

  DESCRIPTION OF SYMBOLS 1,11 ... Current line to be measured, 2, 9 ... Shield plate, 3 ... Terminal, 4, 12 ... Support, 5, 8, 10 ... Fixing tool, 6 ... Core, 7 ... Magnetoelectric conversion element, 13 ... Cylindrical shape 14, current sensor

Claims (6)

It is obtained by bending a single pattern obtained by punching a plate mainly composed of copper or a copper alloy, and is formed by combining a current wire to be measured having a plurality of terminals at both ends, a shield plate, and a support. ,
A fixture having a part of a current line to be measured in a cylindrical part of a shield plate that has been bent.   The fixture according to claim 1, further comprising one or more terminals that can be connected so that the bent cylindrical shield plate has the same potential as a ground pad on the circuit board.   A current line to be measured having a plurality of terminals at both ends, obtained by bending one pattern obtained by punching a cylindrical part of the bent shield plate and a plate material mainly composed of copper or a copper alloy. The fixture according to any one of claims 1 to 2, further comprising a support body therebetween.   The cylindrical part of the shield plate bent according to any one of claims 1 to 3 is substantially U-shaped, and the shield plate is provided with one or more terminals. Ingredients.   A fixture comprising a plurality of current lines to be measured that constitute the fixture according to any one of claims 1 to 3 and claim 4.   A current sensor comprising the fixture according to any one of claims 1 to 3 and claim 4.

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