JP2021152514A - Fluxgate current sensor with saturable core fixture - Google Patents

Abstract

To provide a fixture of a saturable core which is easy to assemble and low in cost, and a fluxgate current sensor including the saturable core fixed to the fixture.SOLUTION: A first support 2 made of a flexible insulating tube and a second support 3 for accommodating and connecting the first support 2 are provided in which the inside of the first support 2 has a hollow portion 6 that accommodates and supports a strip-shaped saturable core 1, the hollow portion 6 forms the first support 2 in a substantially C shape and allows each end of the saturable core 1 accommodated in the first support 2 to extend from each end surface of the first support 2, and a third support 5 is provided with an exciting coil 4 on its outer peripheral surface, and accommodates and supports the first support 2 through which the saturable core is inserted to be accommodated.SELECTED DRAWING: Figure 2

Description

The present invention relates to a fixture for fixing a strip-shaped saturable core using a high magnetic permeability magnetic material, and a fluxgate current sensor provided with the saturable core fixed to the fixture.

Conventionally, as a current detection unit of a fluxgate current sensor, a substantially C-shaped first support made of a resin material, a band-shaped saturable core inserted and housed inside the support, and a saturable core are used. Those provided with an exciting coil for exciting the saturable core and an annular second support made of a resin material for accommodating and holding them, which are arranged on the outer peripheral surface of the inserted first support. be. Since the saturable core is formed in an annular shape along the substantially C-shape after being inserted and accommodated in the substantially C-shaped first support, the saturable core is formed on the substantially C-shaped first support. It has an insertion groove formed along a substantially C-shaped contour, and the insertion groove is formed as a single molded part by alternately forming openings on the upper surface of the cylinder and the lower surface of the cylinder on the opposite side. It has a structure that prevents the saturable core from falling off. (See, for example, Patent Document 1)

Japanese Patent Application Laid-Open No. 2016-125839

As described above, the saturable core is inserted into the insertion groove of the substantially C-shaped first support provided in the fluxgate current sensor disclosed in Patent Document 1, and the saturable core is omitted. The insertion groove for supporting the ring-shaped posture along the C-shape and maintaining the ring-shaped posture has a structure in which the upper surface of the cylinder and the lower surface of the opposite side cylinder facing the cylinder are alternately opened. There is.

Therefore, when the saturable core is inserted into the first support, the tip of the saturable core is likely to be caught in the opening of the insertion groove, which deteriorates the insertion workability and increases the manufacturing cost.

Further, since the first support has a substantially C-shaped shape, it is difficult to directly wind the first support as an exciting coil, and the first support is spirally wound around a linear cylindrical shaft in advance (winding). ), The exciting coil needs to be fed and arranged from one end of the first support having a substantially C shape.

Furthermore, the size of the through hole provided in the center of the case of the current sensor for inserting this conductor corresponds to the change in the cross-sectional area (thickness) of the primary conductor depending on the magnitude of the primary current measured by the current sensor. When manufacturing flux gate current sensors having different sizes, the annular second support that accommodates and holds the substantially C-shaped first support and the substantially C-shaped first support around which an exciting coil is wound. It is necessary to prepare an injection molding mold for each of the supports by matching the annular diameter to the size of the through hole in the center of the case.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a fluxgate current sensor that can be easily assembled and manufactured at low cost.

The fixture for fixing the strip-shaped saturable core of the present invention includes a first support made of a flexible insulating tube, a second support connected to both ends of the first support, and a first support. It comprises a third support for accommodating the body, the first support having a hollow portion for accommodating and supporting a saturable core, the hollow portion penetrating both end faces of the first support. Each end of the housed saturable core extends from each end face of the first support, and the third support houses the first support with an exciting coil disposed on the outer peripheral surface. To do.

According to the present invention, since the first support is a flexible insulating tube, the inner wall surface of the hollow portion is smooth and has few irregularities, and when the saturable core is inserted into the hollow portion, it is prevented from being caught by the inner wall. Prevention Assembling becomes easier and working time can be shortened.

Further, since the first support through which the saturable core is inserted is connected in an annular shape by the second support, the length of the flexible insulating tube serving as the first support and the length of the saturable core By changing the size, it is possible to easily manufacture a current sensor unit with an annular diameter, which can be used to change the diameter of the primary conductor through hole of the current sensor housing, which is obtained from the change in the cross-sectional area of the primary conducting conductor. Can be flexibly handled. Further, it is not necessary to manufacture a molding die and an injection molded part, and the manufacturing cost can be suppressed.

It is an exploded perspective view which shows all the components of the fluxgate current sensor in Embodiment 1 of this invention. It is an exploded perspective view which shows the component of the current detection unit of the fluxgate current sensor in Embodiment 1 of this invention. FIG. 5 is a perspective view showing a saturable core, a first support, and an exciting coil, which are components of the current detection unit according to the first embodiment of the present invention. It is a perspective view of the current detection unit in Embodiment 1 of this invention. FIG. 5 is a perspective view in which a saturable core, a first support, and an exciting coil, which are components of the current detection unit according to the first embodiment of the present invention, are annular. It is explanatory drawing of the detailed shape of the 2nd support which is a component element of the current detection unit in Embodiment 1 of this invention. It is a perspective view which shows the 3rd support which is a component of the current detection unit in Embodiment 1 of this invention.

Embodiment 1.
FIG. 1 is an exploded perspective view showing all the components of the fluxgate current sensor 100 according to the first embodiment of the present invention, and FIG. 2 is an exploded view showing the current detection unit 50 of the fluxgate current sensor 100 according to the first embodiment of the present invention. The perspective view and FIG. 3 are perspective views (excluding the third support 5) showing the saturable core 1, the first support 2, and the excitation coil 4, which are the components of the current detection unit 50. FIG. 4 is a perspective view of the current detection unit 50, and FIG. 5 is a perspective view of the saturable core 1, the first support 2, and the exciting coil 4, which are components of the current detection unit 50, in an annular shape (third support). 5), FIG. 6 is an explanatory view of the detailed shape of the second support 3 which is a component of the current detection unit 50, and FIG. 7 shows a third support 5 which is a component of the current detection unit 50. It is a perspective view.

As shown in FIG. 1, the flux gate current sensor 100 according to the first embodiment is connected to an annular current detection unit 50 and terminals of the current detection unit 50 to input a measurement electronic circuit unit (not shown) and an electric signal. The circuit board portion 20 on which the output connector 22 is mounted, the cylindrical outer magnetic shield 30 arranged outside the current detection unit 50 and surrounding the current detection unit 50 from the outer surface and the bottom surface, and the inside of the current detection unit 50. It is composed of a cylindrical inner magnetic shield 40 arranged in, a case 60 and a cover 70 for accommodating these parts, and a screw 21 for fixing the circuit board portion 20 to the case 60.

As shown in FIG. 2, the current detection unit 50 of the flux gate current sensor 100 is composed of, for example, a strip-shaped saturable core 1 made of a highly magnetically permeable magnetic material and, for example, a flexible insulating tube supporting the saturable core 1. The support 1 of 1, the second support 3 made of, for example, a resin material connected to the first support 2 to form an annular shape, and the urethane, for example, arranged on the outer peripheral surface of the first support 2. An exciting coil 4 made of a copper wire and a third support 5 made of a flexible insulating tube having the same quality and a different diameter as the first support 2 arranged so as to cover the outer shell of the exciting coil 4. , A pair of magnetic cores 11a and 11b made of, for example, permalloy, which are arranged on the outer shell of the third support 5 so as to cover the outer shell, and a core case 12a, which is made of, for example, a resin material that surrounds these members in a pair. 12b and the like.

As shown in FIG. 3, the first support 2 is a linear flexible insulating tube having free ends at both ends, and has a hollow portion 6 inside. The hollow portion 6 has a size capable of inserting the saturable core 1, and penetrates both end faces (end faces of free ends) of the first support 2, and one of the penetrating ends is the saturable core 1. It is an insertion port 6a for inserting.

As shown in FIG. 6, the second support 3 has substantially V-shaped groove portions 3a and 3b which are arcuate and have substantially V-shaped cross sections 15 at both ends, and an insertion groove portion which superimposes and holds the saturable core 1 in the center. It has 3c.
The V-shaped walls of the substantially V-shaped groove portions 3a and 3b have a spring property that can change the position with a force that can be pressed by a finger.
Further, the second support 3 is formed with connection terminals 13a to 13d (for example, made of brass) and support columns 3d to 3g for supporting the connection terminals 13a to 13d (for example, made of brass).
The strut portions 3d to 3g are sequentially arranged at intervals along the arc shape of the second support 3, and the strut portions 3d and 3g are slightly inside the strut portions 3e and 3f (axial center). It is arranged on the side).

As shown in FIG. 7, the third support 5 is inserted so as to cover the outer peripheral surface of the exciting coil 4, and has a hollow inner diameter larger than the winding diameter of the exciting coil 4.

Here, the procedure for assembling the current detection unit 50 of the fluxgate current sensor 100 will be described.
First, as shown in FIG. 3, in a state where the first support 2 which is a flexible insulating tube is linear, a linear cylindrical shaft jig for winding is inserted into the hollow portion 6, and the exciting coil 4 is inserted. Is solenoid-wound.

Next, for example, five third supports 5 are inserted so as to cover the outer peripheral surface of the exciting coil 4. (Fig. 7 shows the state after insertion)
Next, the winding cylindrical shaft jig is removed, and the saturable core 1 is inserted through the insertion port 6a until it penetrates the first support 2.

Next, as shown in FIGS. 5 and 6, the saturable core 1 extending from both end faces of the first support 2 is inserted so as to be sandwiched between substantially V-shaped groove portions 3a and 3b of the second support 3. , It is annularly accommodated so as to overlap with each other at the insertion groove portion 3c.
Next, the V-shaped wall of the substantially V-shaped groove portion 3a is pressed with a finger into the hollow portion 6 of the first support 2 and inserted at a narrow angle. By separating the walls of the above, the V-shaped scissors angle is widened, and the first support 2 and the substantially V-shaped groove 3a of the second support 3 are fixed. The 3b side is also fixed to the first support 2 in the same manner as the 3a side.

Next, as shown in FIG. 2, the magnetic cores 11a and 11b are sandwiched and accommodated, and the core cases 12a and 12b are further sandwiched and fitted and fixed.
This completes the assembly of the current detection unit 50.

The exciting coil 4 (shown in FIG. 2) and the lead wire of the secondary coil (not shown) wound around the outer peripheral surface of the current detection unit 50 are connected to the connection terminals 13a to 13d (shown in FIG. 6) of the current detection unit 50, respectively. It is wound and soldered, and is also soldered and connected to the circuit board unit 20 to which the measurement electronic circuit unit and the connector 22 are soldered and mounted in advance.
As shown in FIG. 1, the flux gate current sensor 100 accommodates the outer magnetic shield 30 and the inner magnetic shield 40 in the case 60, and the circuit board portion 20 to which the current detection unit 50 is soldered and connected is screwed to the case 60 with screws 21. It is fastened and fixed, and the cover 70 is fixed to the case 60 with a snap-fit structure utilizing the elastic force of the resin.

In the current detection unit 50 of the fluxgate current sensor 100 configured in this way, the exciting coil 4 is wound and arranged around the substantially cylindrical outer peripheral surface of the first support 2, but the first support By inserting a linear winding cylindrical shaft jig into the hollow portion 6 of 2, the exciting coil 4 can be directly wound. That is, since the solenoid-wound exciting coil 4 is directly wound around the first support 2, the solenoid-wound exciting coil 4 is previously solenoid-wound on the first support 2 in a substantially C-shaped outer peripheral surface. It is not necessary to insert and dispose of the coil, which simplifies the assembly process and reduces the manufacturing cost.

Further, the first support 2 is made of a flexible insulating tube or the like, the inner wall surface of the hollow portion is smooth and has no unevenness, and the first support 2 is linear and the saturable core 1 is inserted through the wall surface. It is possible to reduce the risk of stressing the saturable core 1 without interfering with and getting caught, and it is easy to assemble and the working time can be shortened.

Furthermore, the length of the flexible insulating tube of the first support 2 and the length of the saturable core 1 and the length or number of the third support 5 can be easily changed to easily perform an annular primary. Conductor through holes can be made. That is, it is not necessary to prepare different molding dies each time the primary conductor through hole is changed like a substantially C-shaped support or an annular support formed of a resin molded product, and the manufacturing cost is suppressed. be able to.

1 ... Saturable core 2 ... First support 3 ... Second support 3a, 3b ... Approximately V-shaped groove 3c ... Insertion groove 3d to 3g ... Strut part 4 ... Exciting coil 5 ... Third support 6 ... Hollow portions 11a, 11b ... Magnetic cores 12a, 12b ... Core cases 13a to 13d ... Connection terminals 15 ... Approximately V-shaped cross section 20 ... Circuit board portion 21 ... Screws 22 ... Connector 30 ... Outer magnetic shield 40 ... Inner magnetic shield 50 ... Current detection unit 100 ... Fluxgate current sensor

Claims (6)

A fixture for fixing a strip-shaped saturable core, the first support made of a flexible insulating tube, the second support connected to both ends of the first support, and the first support. A third support for accommodating the support is provided, and the first support has a hollow portion for accommodating and supporting the saturable core, and the hollow portion is of the first support. Each end of the saturated core that penetrates both end faces and is accommodated is extended from each end face of the first support, and the third support is provided with an exciting coil on the outer peripheral surface. A fixture characterized by accommodating the first support. The fixture according to claim 1, wherein the exciting coil is wound around an outer peripheral surface of the first support in a linearly extended state. The second support has insertion portions to be inserted and fixed in the hollow portion at both ends thereof, and both ends of the saturable core extending from the end faces of the first supports are sandwiched in a state of being overlapped with each other. The fixture according to claim 1 or 2, further comprising an insertion groove that is movable in the circumferential direction with respect to each other. The fixture according to any one of claims 1 to 3, wherein the third support comprises a flexible insulating tube divided into a plurality of parts. The fixture according to any one of claims 1 to 4, wherein the insertion portion of the second support has a substantially V-shaped cross section having a spring property. A fluxgate current sensor comprising a saturable core supported by the fixture according to any one of claims 1 to 5.

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