Air core coil

【0001】

[Technical field to which the invention belongs]

The present invention relates to an air-core coil used in a current sensor that measures, for example, an impulse large current flowing through a conductor to be measured.

【0002】

[Conventional technology]

The air-core coil is a coil that does not have a ferromagnet such as an iron core in the winding core, and has a property of not becoming magnetically saturated. Therefore, when the air-core coil is used as a current sensor for measuring the current flowing through the conductor to be measured, it is possible to measure a wide current range. Further, a Rogoski coil is used for the air core coil of the current sensor in order to suppress a measurement error due to an external electromagnetic field. The Rogowski coil is a coil in which a conducting wire is wound in a solenoid shape and then returned from the end of winding to the beginning of winding.

【0003】

A conventional Rogowski coil is constructed by depositing gold on a flat printed circuit board. Since this Rogowski coil is constructed on a flat printed circuit board, it can be manufactured almost completely symmetrically in the axial direction (see, for example, Patent Document 1).

【0004】

[Patent Document 1]

Japanese Unexamined Patent Publication No. 6-176947 [0005]

[Problems to be Solved by the Invention]

When manufacturing a conventional air-core coil in this way, it is necessary to arrange a pattern of gold deposits on a flat printed circuit board, which is troublesome. Further, when a conventional air-core coil is used for a current sensor, the area surrounded by the winding coil and the area surrounded by the rewinding coil of the Rogowski coil are different when viewed along the axis of the conductor to be measured. Therefore, there is a difference in the magnitude of the induced electromotive force generated in each, and the measurement error becomes large.

【0006】

Therefore, an object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to obtain an air-core coil having a small measurement error and easy to manufacture.

【0007】

[Means for solving problems]

The air-core coil according to the present invention is an insulating substrate having a front surface, a back surface, a substrate opening penetrating the front surface and the back surface, and a substrate opening through which a conductor to be measured is passed, and around the substrate opening on the front surface and the back surface. It has a plurality of conductor portions provided substantially radially and a plurality of connecting conductor portions connected to each end portion of each conductor portion on the front surface and each conductor portion on the back surface, and each conductor portion and each connecting conductor portion. A coil body is provided in a coil shape, and a plurality of grooves and a plurality of partitions extending substantially radially around the substrate opening are alternately arranged on at least one of the front surface and the back surface, and each conductor portion is provided. Each of the grooves is provided, and the width of the tip of the partition is smaller than the width of the base of the partition.

【0008】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Embodiment 1. FIG. 1 is a front view showing an air-core coil according to a first embodiment of the present invention, and FIG. 2 is a partially enlarged view showing a coil body 3 near a connection point 7 in FIG. In the figure, the air-core coil 1 includes an insulating substrate 2 made of a non-magnetic material such as resin, and a coil body 3 provided on the insulating substrate 2. The insulating substrate 2 is a disk having a circular substrate opening 4 in the center through which the conductor to be measured is passed. The coil main body 3 has a rewinding coil portion 5 and a rewinding coil portion 6 formed so that a lead wire is wound along the outer circumference of the substrate opening 4.

【0009】

The rewinding coil portion 5 and the rewinding coil portion 6 are electrically connected in series at the connection point 7. An induced electromotive force corresponding to the current flowing through the conductor to be measured is generated in each of the conducting wires of the winding coil portion 5 and the rewinding coil portion 6. The winding forward coil portion 5 and the rewinding coil portion 6 are wound so that the induced electromotive forces are electrically oriented in the same direction. Further, the conducting wire constituting the rewinding coil portion 5 and the rewinding coil portion 6 is a copper conductive film adhered to the insulating substrate 2 in a coil shape. That is, the air-core coil 1 is a rewinding coil in which the conductor is wound forward and the lead wire is connected to the end portion of the winding lead coil portion 5 and is rewound along the winding coil portion 5. It is a logoski coil composed of part 6.

【0010】

A signal processing circuit 32 electrically connected to the extraction portions 30 and 31 of the coil main body 3 is attached to the insulating substrate 2. The signal processing circuit 32 is a circuit that integrates the induced current generated in the coil body 3. The induced current is generated in the coil body 3 as a differential value of the current waveform flowing through the conductor to be measured, and the current waveform of the conductor to be measured is restored by the integration process of the signal processing circuit 32.

【0011】

A plurality of first front surface conductor portions 10 (conductor portions) which are conductive films and a plurality of first back surface conductor portions 11 (conductor portions) which are conductive films are attached to the front surface 8 and the back surface 9 of the insulating substrate 2, respectively. ing. Further, the insulating substrate 2 is provided with a plurality of connecting conductor portions 12 penetrating the insulating substrate 2. The winding lead coil portion 5 is formed in a coil shape by connecting a plurality of first surface conductor portions 10 and a plurality of first back surface conductor portions 11 in series electrically via each connecting conductor portion 12. ..

【0012】

A plurality of second front surface conductor portions 15 (conductor portions) which are conductive films and a plurality of second back surface conductor portions 16 (conductor portions) which are conductive films are also attached to the front surface 8 and the back surface 9 of the insulating substrate 2, respectively. Has been done. Each second surface conductor portion 15 is arranged between each first surface conductor portion 10, and each second back surface conductor portion 16 is arranged between each first back surface conductor portion 11. Further, the insulating substrate 2 is provided with a plurality of connecting conductor portions 17 penetrating the insulating substrate 2. The rewind coil portion 6 is formed in a coil shape in which a plurality of second front surface conductor portions 15 and a plurality of second back surface conductor portions 16 are electrically connected in series via each connecting conductor portion 17. .. In addition, in FIG. 1 and FIG. 2, the conductive film formed on the back surface 9 is shown by a broken line.

【0013】

Each first surface conductor portion 10 is arranged around the substrate opening 4 so that the inner end portion 10a is arranged on the side closer to the substrate opening 4 and the outer end portion 10b is arranged on the side farther from the substrate opening 4. They are arranged substantially radially at a constant pitch.

【0014】

Each first back surface conductor portion 11 is bent on a side away from the substrate opening 4 for connection to the connecting conductor portion 12. Further, in each first back surface conductor portion 11, the substrate opening 4 is arranged so that the inner end portion 11a is arranged on the side closer to the substrate opening 4 and the outer end portion 11b is arranged on the side farther from the substrate opening 4. They are arranged at a constant pitch in a substantially radial pattern around the.

【0015】

The second surface conductor portions 15 are arranged at a constant pitch on the surface 8 so as to alternate with the first surface conductor portions 10 substantially radially around the substrate opening 4. Further, each second surface conductor portion 15 is arranged so that each inner end portion 15a and each outer end portion 15b are closer to the substrate opening 4 than each inner end portion 10a and each outer end portion 10b, respectively. ing.

【0016】

Each second back surface conductor portion 16 is bent on the side close to the substrate opening 4 for connection to the connecting conductor portion 17. Further, each of the second back surface conductor portions 16 is arranged at a constant pitch on the back surface 9 so as to alternate with the first back surface conductor portion 11 substantially radially around the substrate opening 4. Further, each second back surface conductor portion 16 is arranged so that each inner end portion 16a and each outer end portion 16b are closer to the substrate opening 4 than each inner end portion 11a and each outer end portion 11b, respectively. ing.

【0017】

As shown in FIG. 1, the substantially radial portions of the first front surface conductor portion 10 and the first back surface conductor portion 11 are arranged so as to face each other, and the substantially radial portions of the second front surface conductor portion 15 and the second back surface conductor portion 16 are arranged. The portions are arranged so as to face each other. When viewed along the thickness direction of the insulating substrate 2, each of the first front surface conductor portions 10 and each first back surface conductor portion 11 overlaps each inner end portion 10a and each inner end portion 11a, and each outer end portion 11a overlaps with each other. The portions 10b and the outer ends 11b are arranged so as to overlap each other. Further, in each of the second front surface conductor portion 15 and each second back surface conductor portion 16, when viewed along the thickness direction of the insulating substrate 2, each inner end portion 15a and each inner end portion 16a overlap each other. The outer end 15b and each outer end 16b are arranged so as to overlap each other. In FIG. 1, for the sake of clarity, substantially radial portions facing each other are shown side by side.

【0018】

The connecting conductor portion 12 electrically connects a plurality of first inner connecting conductor portions 13 that electrically connect the inner end portions 10a and 11a that overlap each other in FIG. 1, and the outer end portions 10b and 11b that overlap each other in FIG. It is composed of a plurality of first outer connecting conductor portions 14 connected to.

【0019】

The connecting conductor portion 17 electrically connects a plurality of second inner connecting conductor portions 18 that electrically connect each inner end portion 15a and each inner end portion 16a, and each outer end portion 15b and each outer end portion 16b. It is composed of a plurality of second outer connecting conductor portions 19.

【0020】

FIG. 3 shows the insulating substrate 2, the rewinding coil portion 5 and the rewinding coil portion 6 when viewed along the outer circumference of the substrate opening 4 of FIG. 1 (along the direction of arrow 27 in FIG. 1). It is a layout drawing. In the figure, a plurality of groove portions 20 are formed on the front surface 8 and the back surface 9 of the insulating substrate 2, respectively. Each groove 20 extends substantially radially around the substrate opening 4 and is arranged along the circumferential direction of the substrate opening 4. The first front surface conductor portion 10, the first back surface conductor portion 11, the second front surface conductor portion 15, and the second back surface conductor portion 16 are attached to the inner surface of each groove portion 20. Further, the connecting conductor portion 12 and the connecting conductor portion 17 are copper conductive films formed on the inner surface of the through holes penetrating the insulating substrate 2 along the thickness direction of the insulating substrate 2, that is, metal through holes. ..

【0021】

Further, the second inner connecting conductor portion 18 is arranged closer to the substrate opening 4 than the first inner connecting conductor portion 13, and the second outer connecting conductor portion 19 is closer to the substrate than the first outer connecting conductor portion 14. It is arranged on the side closer to the opening 4 and on the side farther from the substrate opening 4 than the first inner connecting conductor portion 13.

【0022】

That is, the rewinding coil portion 5 and the rewinding coil portion 6 are formed in a region surrounded by the conducting wire of the rewinding coil portion 5, that is, the first surface conductor portion 10, the first surface conductor portion 10, when viewed along the outer periphery of the substrate opening 4. 1 The area surrounded by the back surface conductor portion 11, the first inner connecting conductor portion 13 and the first outer connecting conductor portion 14 (hereinafter referred to as the cross-sectional area of the rewinding coil portion 5) and the lead wire of the rewinding coil portion 6 are surrounded. The region, that is, the region surrounded by the second front surface conductor portion 15, the second back surface conductor portion 16, the second inner connecting conductor portion 18, and the second outer connecting conductor portion 19 (hereinafter referred to as the cross-sectional region of the rewind coil portion 6). However, most of them are arranged so as to overlap each other. Further, the area of the cross-sectional area of the rewinding coil portion 5 and the area of the cross-sectional area of the rewinding coil portion 6 are substantially the same.

【0023】

FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. In the figure, a partition portion 21 is formed between the groove portions 20 adjacent to each other. The partition portion 21 is formed by forming each groove portion 20 so that a part of the insulating substrate 2 is left. A flat surface 23 perpendicular to the thickness direction of the insulating substrate 2 is formed on the tip portion 22 of each partition portion 21. The width W1 of the plane 23 is smaller than the width W2 of the base 24 of the partition 21. That is, the width W1 along the arrangement direction of the groove portions 20 of the plane 23 is smaller than the width W2 along the arrangement direction of the groove portions 20 of the base portion 24. Here, the open side of each groove portion 20 is widened to form a tapered surface 25 at the tip portion 22 of the partition portion 21, so that a flat surface having a width W1 smaller than the width W2 of the base portion 24 adjacent to the bottom portion of each groove portion 20. 23 is formed. No conductive film is attached to the flat surface 23. Therefore, the conductive films attached to the groove portions 20 adjacent to each other, that is, the first surface conductor portion 10 and the second surface conductor portion 15, and the first back surface conductor portion 11 and the second back surface conductor portion 16 are insulated from each other. ..

【0024】

Next, the operation will be described. When a current is passed through the conductor to be measured, magnetic flux is passed through the cross-sectional region of the rewinding coil portion 5 and the cross-sectional region of the rewinding coil portion 6, and an induced current is generated in the coil body 3. Since this induced current flows in the direction of the arrow shown in FIG. 2, the induced currents generated at each location do not electrically cancel each other out. The induced current flowing through the conducting wire of the coil body 3 is integrated in the signal processing circuit 32 to calculate the current waveform flowing through the conductor to be measured.

【0025】

Next, the manufacturing method will be described. FIG. 5 is a vertical cross-sectional view (cross-sectional view along the circumferential direction of the substrate opening 4) showing the shape of the insulating substrate 2 of FIG. 4 in the process of being manufactured. First, an engineering plastic having a small thermal expansion is molded into a plate having a cross-sectional shape as shown in FIG. 5 by a molding method such as a compression molding method or a casting method. That is, a plurality of partition portions 21 having a top portion 33 having a width smaller than the width W1 of the flat surface 23 and a plurality of groove portions 20 are alternately formed on the front surface and the back surface of the engineering plastic plate.

【0026】

Then, after forming a plurality of through holes penetrating the engineering plastic plate between the ends of the groove portions 20 on the front surface and the back surface, the conductive film is adhered to the entire surface of the plate and the inner surface of the through holes by dry plating or wet plating. As a result, the conductive film can be adhered to the entire surface of the plate and the inner surface of the through hole with a uniform thickness. Then, the front surface, the back surface, the outer surface, and the inner surface of the substrate opening 4 of the engineering plastic plate are polished to remove the conductive film excluding the inner surface of the groove 20 and the inner surface of the through hole. At this time, on the front surface and the back surface of the engineering plastic plate, the top 33 of the partition portion 21 is removed together with the conductive film up to the polishing position 40. As a result, the conductive film is separated into each of the groove portions 20 to become each conductor portion. The coil body 3 is composed of a conductive film left on the inner surface of the groove 20 and the inner surface of the through hole, and the air core coil 1 is completed.

【0027】

Since the width of the top 33 is smaller than the width W1 of the flat surface 23 in this way, the conductive film can be easily removed by polishing. Further, since the width W1 of the plane 23 formed in the partition portion 21 is smaller than the width W2 of the base 24, the amount of the conductive film to be removed can be reduced, and the conductive film can be removed in a short time. .. Therefore, the air-core coil 1 can be manufactured in large quantities and at low cost.

【0028】

Further, the second inner connecting conductor portion 18 is arranged closer to the substrate opening 4 than the first inner connecting conductor portion 13, and the second outer connecting conductor portion 19 is closer to the substrate than the first outer connecting conductor portion 14. Since it is arranged on the side closer to the opening 4 and on the side farther from the substrate opening 4 than the first inner connecting conductor portion 13, when viewed along the circumferential direction of the substrate opening 4, the coil body 3 In a state where most of the cross-sectional regions of the rewinding coil portion 5 and the rewinding coil portion 6 of the above overlap each other, the areas of the respective cross-sectional regions can be made substantially the same. From this, it is possible to further standardize the magnetic flux that generates the induced electromotive force in the rewinding coil portion 5 and the rewinding coil portion 6, and it is possible to make the magnitudes of the induced electromotive force generated in each coil substantially equal. it can. Therefore, when the air-core coil 1 is used for the current sensor, the measurement sensitivity can be improved and the measurement error can be reduced.

【0029】

Further, since the lead wire of the coil body 3 can be formed almost completely symmetrically and uniformly with respect to the axis of the substrate opening 4, the measurement sensitivity can be further improved and the measurement error can be reduced. ..

【0030】

Further, since the insulating substrate 2 is molded by the molding method, there are no restrictions on the size and shape of the insulating substrate 2, and the shape of the coil body 3 can be easily made into a desired shape.

【0031】

Embodiment 2. FIG. 6 is a front view showing a configuration of an air-core coil according to a second embodiment of the present invention. Further, FIG. 7 is a partially enlarged view showing the coil main body 3 near the connection point 7 in FIG. In the figure, the members or parts corresponding to the air core coil 1 in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted here.

【0032】

The coil body 3 of the air-core coil 1 according to the second embodiment has a rewinding coil portion 5 and a rewinding coil portion 6 provided on the insulating substrate 2 and connected in series with each other.

【0033】

As shown in FIG. 6, when viewed along the thickness direction of the insulating substrate 2, a serrated pattern is formed by each of the first front surface conductor portions 10 and each first back surface conductor portion 11 of the winding lead coil portion 5. Has been done. Further, each second front surface conductor portion 15 and each second back surface conductor portion 16 of the rewind coil portion 6 also form a sawtooth pattern, and the sawtooth pattern of the rewind coil portion 6 is the rewind coil portion 5. It is placed inside the serrated pattern of. The serrated regions surrounded by the lead wires of the rewinding coil portion 5 and the rewinding coil portion 6 are the front region of the rewinding coil portion 5 and the front region of the rewinding coil portion 6, respectively.

【0034】

That is, when viewed along the thickness direction of the insulating substrate 2, each inner end portion 15a of the second front surface conductor portion 15 and the second back surface conductor portion 16 connected to each other via the second outer connecting conductor portion 19 , 16a are arranged so as to be separated from each other along the arrangement direction of each of the second front surface conductor portions 15 and each of the second back surface conductor portions 16. Further, the outer end portions 15b and 16b of the second front surface conductor portion 15 and the second back surface conductor portion 16 connected to each other via the second inner connecting conductor portion 18 are also the second surface conductor portions 15 and the second surfaces. The back surface conductor portions 16 are arranged so as to be separated from each other along the arrangement direction.

【0035】

Further, when viewed along the thickness direction of the insulating substrate 2, each inner end portion 10a of the first front surface conductor portion 10 and the first back surface conductor portion 11 connected to each other via the first outer connecting conductor portion 14 , 11a are arranged so as to be separated from each other along the arrangement direction of each of the first front surface conductor portions 10 and each of the first back surface conductor portions 11. Further, the outer end portions 10b and 11b of the first surface conductor portion 10 and the first back surface conductor portion 11 connected to each other via the first inner connecting conductor portion 13 are also the first surface conductor portions 10 and the first ones, respectively. The back surface conductor portions 11 are arranged so as to be separated from each other along the arrangement direction.

【0036】

Further, the inner end portions 15a and 16a of the second front surface conductor portion 15 and the second back surface conductor portion 16 are more than the inner end portions 10a and 11a of the first surface conductor portion 10 and the first back surface conductor portion 11. It is arranged on the side close to the substrate opening 4. Further, the outer end portions 15b and 16b of each of the second front surface conductor portion 15 and each second back surface conductor portion 16 are larger than the outer end portions 10b and 11b of each first surface conductor portion 10 and each first back surface conductor portion 11. It is arranged on the side closer to the substrate opening 4, and is arranged on the side farther from the substrate opening 4 than the inner ends 10a and 11a of each of the first front surface conductors 10 and each of the first back surface conductors 11.

【0037】

Considering that the first front surface conductor portion 10 and the first back surface conductor portion 11 are vectors starting from the outer end portion 10b and the outer end portion 11b that overlap each other, the substrate opening 4 is formed in the direction of synthesis of the vectors. Each first front surface conductor portion 10 and each first back surface conductor portion 11 are provided so that the center point exists. Similarly, considering that the second front surface conductor portion 15 and the second back surface conductor portion 16 are vectors starting from the outer end portion 15b and the outer end portion 16b that overlap each other, the substrate opening is formed in the direction of synthesis of the vectors. Each second front surface conductor portion 15 and each second back surface conductor portion 16 are provided so that the center point of 4 exists. Other configurations, manufacturing methods, and operations are the same as those in the first embodiment.

【0038】

Here, the induced currents in the rewinding coil section 5 and the rewinding coil section 6 are not only the magnetic field from the conductor to be measured, but also the external electromagnetic fields that pass through the front regions of the rewinding coil section 5 and the rewinding coil section 6. It also occurs depending on the world. The induced current due to the external electromagnetic field causes a measurement error of the current sensor. Therefore, in order to cancel the induced currents due to the external electromagnetic fields, the areas of the front regions of the rewinding coil portion 5 and the rewinding coil portion 6 should be close to the same.

【0039】

Therefore, according to the air-core coil 1 according to the second embodiment, the same effect as that of the first embodiment is obtained, and the area of the front region of the rewinding coil portion 5 and the area of the front region of the rewinding coil portion 31 are the same. The area difference can be further reduced, and the measurement error due to the external electromagnetic field can be further reduced.

【0040】

In the above-described first and second embodiments, the conductive film is removed by polishing. For example, a resist agent is applied to a portion where the conductive film is to be removed, and the conductive film is adhered to the entire surface of the insulating substrate 2. After this, the conductive film may be removed together with the resist agent, or the conductive film to be removed may be cut by a laser or the like.

【0041】

Further, in the above-described first and second embodiments, the insulating substrate 2 is not limited to molding by the molding method, and may be molded by, for example, cutting.

【0042】

Further, in the above-described first and second embodiments, a plurality of air core coils 1 may be connected and used in order to further improve the measurement sensitivity of the current sensor. In this case, one signal processing circuit 32 is provided for each of the plurality of air core coils 1. The air core coils 1 are arranged so that the substrate openings 4 are aligned, and in order to connect the coil main bodies 3 to each other, connection terminals from the drawer portion 30 are provided on one of the front surface 8 and the back surface 9, and the other is a drawer. A connection terminal from unit 31 is provided. Further, in order to facilitate the connection between the connection terminals, concave portions and convex portions are formed in the connection terminals, and the concave and convex portions are fitted to each other so that the connection terminals are connected to each other.

【0043】

Further, in the first and second embodiments, the second inner connecting conductor portion 18 and the first outer connecting conductor portion 14 are conductive films adhered to the inner surface of the through hole, but the modification of the first embodiment. As shown in FIG. 8 showing an example, even if the conductive film is adhered to the inner surfaces of a plurality of inner groove portions 34 and outer groove portions 35 formed on the inner surface of the substrate opening 4 and the outer surface of the insulating substrate 2, respectively. Good. As a result, the number of through holes formed in the insulating substrate 2 can be reduced, and the second inner connecting conductor portion 18 and the first outer connecting conductor portion 14 can be more easily configured. In this case, a tapered surface 37 is formed between the inner groove portions 34 and the tip portion of the partition portion 36 between the outer groove portions 35 (on the open side of the groove portions 34 and 35). Further, the through hole, the inner groove portion 34, and the outer groove portion 35 may be mixed to form each second inner connecting conductor portion 18 and each first outer connecting conductor portion 14.

【0044】

Embodiment 3. FIG. 9 is a partial perspective view showing a configuration of an air-core coil according to a third embodiment of the present invention. In the figure, a conductive shield 41, which is a conductive film, is attached to the outer surface of the insulating substrate 2 and the inner surface of the substrate opening 4 according to the first or second embodiment. The conductive shield 41 is one in which a conductive metal such as copper is electrically grounded.

【0045】

The conductive shield 41 is used on the outer surface of the insulating substrate 2 and the substrate during polishing after the conductive film is adhered to the entire surface of the insulating substrate 2 during the production of the air core coil 1 in the first embodiment. It is formed by leaving a conductive film without polishing the inner surface of the opening 4.

【0046】

Here, the connecting conductor portions 12 and 17 (see FIG. 2) of the coil body 3 (see FIG. 1) provided on the insulating substrate 2 are conductive films adhered to the inner surface of the through hole, and are conductive shields 41. It is designed not to short-circuit. Other configurations are the same as those in the first embodiment.

【0047】

Since the conductive shield 41 is attached to the outer surface of the insulating substrate 2 and the inner surface of the substrate opening 4 in this way, the generation of induced electromotive force by the external electromagnetic field in the coil body 3 (see FIG. 1) is generated. It can be suppressed by the conductive shield 41. Here, since the conductive shield 41 is grounded, it is not charged by the induced electromotive force generated by the external electromagnetic field.

【0048】

Embodiment 4. FIG. 10 is a partial perspective view showing a configuration of an air-core coil according to a third embodiment of the present invention. In the figure, an insulating layer 42 made of an insulating material is provided on the front surface, the back surface, the outer surface, and the inner surface surface of the substrate opening 4 of the insulating substrate 2 according to the first or second embodiment. A conductive shield 43, which is a conductive film, is attached to the outer peripheral surface of the insulating layer 42. That is, the coil body 3 (see FIG. 1) and the insulating substrate 2 are covered (that is, surrounded) by the conductive shield 43 via the insulating layer 42. The conductive shield 43 is one in which a conductive metal such as copper is electrically grounded. Other configurations are the same as those in the first embodiment.

【0049】

Since the coil body 3 (see FIG. 1) is surrounded by the conductive shield 43 in this way, the generation of induced electromotive force due to the external electromagnetic field in the coil body 3 (see FIG. 1) is further suppressed by the conductive shield 41. can do.

【0050】

The insulating layer 42 does not need to completely surround the insulating substrate 2, and if the conductive shield 43 is kept in a state where it does not come into contact with the internal coil body 3 (see FIG. 1), for example, in a grid pattern or It may be a plurality of support protrusions.

【0051】

Further, in the third and fourth embodiments, the conductive shields 41 and 43 are conductive films, but may be, for example, a metal plate. Further, if the air core coil according to the second embodiment is used instead of the air core coil according to the first embodiment, the measurement error due to the external electromagnetic field of the current sensor can be further reduced.

【0052】

[Effect of the invention]

As is clear from the above description, in the air-core coil according to the present invention, a plurality of grooves and a plurality of partitions extending substantially radially around the substrate opening are alternately arranged on at least one of the front surface and the back surface. The conductor portion is provided in each groove portion, and the width of the tip portion of the partition portion is smaller than the width of the base portion of the partition portion. By leaving the conductive film as the conductor portion, the amount of the conductive film to be removed can be reduced, and the conductor portion can be formed in a short time.

[Simple explanation of drawings]

FIG. 1 is a front view showing an air core coil according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged view showing a coil body near the connection point of FIG.

3 is a layout diagram showing an insulating substrate, a rewinding coil portion, and a rewinding coil portion when viewed along the outer circumference of the substrate opening of FIG. 1. FIG.

FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG.

5 is a cross-sectional view taken along the circumferential direction of the substrate opening showing the shape of the insulating substrate of FIG. 4 in the process of being manufactured.

FIG. 6 is a front view showing a configuration of an air core coil according to a second embodiment of the present invention.

7 is a partially enlarged view showing a coil body near the connection point of FIG. 6. FIG.

FIG. 8 is a partial perspective view showing an air core coil according to a modified example of the first embodiment of the present invention.

FIG. 9 is a partial perspective view showing a configuration of an air core coil according to a third embodiment of the present invention.

FIG. 10 is a partial perspective view showing a configuration of an air core coil according to a fourth embodiment of the present invention.

[Explanation of symbols]

1 Air-core coil, 2 Insulating substrate, 3 Coil body, 4 Substrate opening, 5 Rewinding coil, 6 Rewinding coil, 8 Front, 9 Back, 10 1st surface conductor (front conductor), 11th 1 Back surface conductor (back surface conductor), 12, 17 Connection conductor, 13 1st inner connection conductor (inner connection conductor), 14 1st outer connection conductor (outer connection conductor), 15 2nd surface conductor Part (front conductor part), 16 2nd back surface conductor part (back surface conductor part), 18 2nd inner connection conductor part (inner connection conductor part), 19 2nd outer connection conductor part (outer connection conductor part), 20 groove part, 21,36 Partition, 22 Tip, 24 Base, 33 Top, 34 Inner Groove, 35 Outer Groove.