WO2015079869A1

WO2015079869A1 - Gapless magnetic core, coil device using same, and coil device manufacturing method

Info

Publication number: WO2015079869A1
Application number: PCT/JP2014/079209
Authority: WO
Inventors: 今西　恒次; 康臣 ▲高▼橋; 吉森　平
Original assignee: 株式会社エス・エッチ・ティ
Priority date: 2013-11-26
Filing date: 2014-11-04
Publication date: 2015-06-04
Also published as: JP6039538B2; TW201535438A; JP2015103702A

Abstract

The present invention provides the following: a gapless magnetic core the quality of which excels with respect to magnetic characteristics and the like, with which fluctuations in such characteristics are small, and which excels in manufacturing efficiency; a coil device using the same; and a coil device manufacturing method. This gapless magnetic core (10) is formed as follows: an annular member (20) that includes an annular magnetic body (21) made of a magnetic material is cut by a first cutting part (27) and a second cutting part (28) that cross an outer circumferential surface and an inner circumferential surface and approach each other going towards the inner circumference of the annular member; a main body (30) is obtained that comprises a first end surface (32) that is cut by the first cutting part (27) and a second end surface (33) that is cut by the second cutting part; a segment (40) is obtained that comprises a first end surface (43) cut by the first cutting part and a second end surface (44) that is cut by the second cutting part; and the segment is pressed into a notch section (31) formed between the first end surface and the second end surface of the main body so that the first end surfaces (32, 42) abut each other and the second end surfaces (33, 43) abut each other.

Description

Gapless magnetic core, coil device using the same, and method of manufacturing the coil device

The present invention relates to a magnetic core used in a coil device installed in a rectifier circuit, a noise prevention circuit, a resonance circuit, etc. in an AC device such as a power supply circuit and an inverter, a coil device using the same, and a method of manufacturing the coil device. is there.

Coil devices mounted on circuits of various AC devices are configured by winding a coil around an annular magnetic core.
In order to perform winding easily, a magnetic core having a gap formed in part is formed, an air core coil wound in advance is inserted from this gap, and then the gap is filled with a magnetic or non-magnetic filler. (For example, refer to FIG. 10 of Patent Document 1).

JP 2011-135091 A

¡In order to backfill the gap, it is necessary to prepare a separate filler. However, for example, when a block such as a magnetic core or a laminated magnetic core formed in advance is inserted as a filler, the filler must be formed to be thinner than the gap interval in order to fit into the gap.

As a result, a gap is formed between one end face of the magnetic core forming the air gap and the filler, and between the filler and the other end face of the magnetic core. And since it is difficult to position and fix a filler accurately in a space | gap, the space | interval of the gaps formed on both sides of a filler is not constant. For this reason, in a coil device using such a magnetic core, variations in quality such as magnetic characteristics occur, such as a decrease in inductance characteristics. In addition, since the filler and the magnetic core have different magnetic characteristics and the like, the magnetic characteristics and the like are deteriorated.

Therefore, the applicant does not prepare the filler separately, but cuts the annularly formed magnetic core in two places perpendicular to the width direction and parallel to each other to cut out a rectangular parallelepiped segment and leave it there. It has been devised to fit a segment into a notch (gap) formed in a C-shaped body. Thereby, a main body and a segment can be made into the same magnetic characteristic, and efficiency improvement of a raw material can be achieved.

However, when cutting the magnetic core with the cutting blade, a cutting allowance corresponding to the blade thickness of the cutting blade is required. Therefore, the segment is thinner than the cutout portion of the main body, and the gap between the segment and the end face of the cutout portion There remains a problem that caused a gap.

An object of the present invention is to provide a gapless magnetic core that is excellent in quality such as magnetic characteristics, has small variations in these characteristics, and has excellent manufacturing efficiency, a coil device using the same, and a manufacturing method of the coil device. is there.

The gapless magnetic core according to the present invention is
An annular member including an annular magnetic body made of a magnetic material is cut at a first cutting portion and a second cutting portion that cross the outer peripheral surface and the inner peripheral surface and approach each other toward the inner peripheral direction of the annular member;
A main body having a main body side first end surface cut by the first cutting portion and a main body side second end surface cut by the second cutting portion;
Obtaining a segment having a segment-side first end face cut by the first cutting part and a segment-side second end face cut by the second cutting part;
In the notch formed between the main body side first end surface and the main body side second end surface, the main body side first end surface and the segment side first end surface, the main body side second end surface and the segment side first It is formed by pushing the segment so that the two end faces abut.

The inner peripheral end surface of the segment protrudes inward from the inner peripheral surface of the main body.

The annular member connects one end of the linear first straight part and the second straight part at a substantially right angle with a curved part having a small radius of curvature, and the other end of the first straight part and the second linear part is curved. It has a teardrop shape connected by a circular arc part with a large radius,
It is desirable that at least one of the first cutting portion or the second cutting portion is cut at the first straight portion or the second straight portion.

It is desirable that the other cutting of the first cutting portion or the second cutting portion is performed between the curved portion and the end of the first straight portion or the second straight portion.

In addition, an angle formed by the first cutting portion and the second cutting portion is preferably 90 ° or less, and is preferably 75 ° or less.

It is preferable that an angle formed by the first cutting portion and the second cutting portion is 20 ° or more.

The main body side first end face and the segment side first end face, and the main body side second end face and the segment side second end face can be fixed by bonding or clamping.

The annular member may include an annular magnetic body and an insulating resin coating that covers the magnetic body.

The magnetic body is preferably a compacted body of magnetic material, and the resin coating is preferably formed by an insert molding method or a resin powder coating method.

The coil device of the present invention comprises:
The gapless magnetic core body described above is configured by inserting an air core coil pre-wound from the notch portion and then pushing the segment into the notch portion.

The manufacturing method of the coil device of the present invention includes:
An annular member including an annular magnetic body made of a magnetic material is cut at a first cutting portion and a second cutting portion that cross the outer peripheral surface and the inner peripheral surface and approach each other toward the inner peripheral direction of the annular member;
A main body having a main body side first end surface cut by the first cutting portion and a main body side second end surface cut by the second cutting portion;
Obtaining a segment having a segment-side first end face cut by the first cutting part and a segment-side second end face cut by the second cutting part;
An air core coil wound in advance is inserted into a notch formed between the main body side first end surface and the main body side second end surface, and the main body side first end surface and the segment side first end surface, The segment is pushed in so that the main body side second end surface and the segment side second end surface are in contact with each other, thereby forming a coil device.

According to the present invention, the main body and the segment are in close contact with each other without having a gap just by pushing the segment into the notch of the main body, so that there is no leakage of magnetic flux due to the gap, and there is no magnetism due to the size of the gap. Since there is no variation in characteristics and the like, it is possible to provide an excellent gapless magnetic core with stable magnetic characteristics and a coil device using the same.

In addition, since the gapless magnetic core of the present invention is made of the same annular member and the main body and the segment, these magnetic characteristics and the like are the same, and the manufactured gapless magnetic core and the coil device using the same are: Stable magnetic properties can be exhibited.

Also, it is not necessary to prepare the main body and the segment separately, and since the cut segment can be used as it is, there is almost no loss of raw materials, and the production efficiency can be increased as much as possible.

FIG. 1 is a plan view (angle α is 60 °) showing an embodiment of a gapless magnetic core of the present invention. FIG. 2 is an enlarged cross-sectional view of a gapless magnetic core obtained by cutting the circled portion of FIG. 1 in the height direction. FIG. 3 is a plan view of the annular member according to the embodiment of the present invention before cutting. FIG. 4 is a cross-sectional view taken along line AA in FIG. FIG. 5 is a plan view of a main body and a segment obtained by cutting the annular member of FIG. FIG. 6 is a plan view showing a state in which a segment is taken out from the main body of FIG. FIG. 7 is a perspective view showing a process of inserting the air-core coil into the main body of FIG. FIG. 8 is a perspective view showing a process of inserting the air-core coil into the main body, following FIG. FIG. 9 is a perspective view showing a process of attaching the segment to the main body in which the air-core coil is inserted. FIG. 10 is a plan view of FIG. FIG. 11 is a perspective view of a coil device obtained by attaching segments. FIG. 12 is a plan view of the coil device of FIG. FIG. 13 is a plan view of a gapless magnetic core having an angle α of 75 °. FIG. 14 is a plan view of a gapless magnetic core having an angle α of 45 °. FIG. 15 is a plan view of a gapless magnetic core having an angle α of 30 °. FIG. 16 is a plan view of a gapless magnetic core having an angle α of 20 °. FIG. 17 is a plan view of a gapless magnetic core having an angle α of 60 ° and shows an embodiment in which the retaining shape of the resin coating layer is changed. FIG. 18 is a plan view of a gapless magnetic core having an angle α of 80 °, and shows an embodiment in which the retaining shape of the resin coating layer is changed. FIG. 19 is a graph showing the DC superposition characteristics of the first embodiment. FIG. 20 is a graph showing a comparison result between the angle α and the initial inductance value in the second embodiment. FIG. 21 is a graph showing a comparison result between the opposing area P of the main body and the segment of the third embodiment and the initial inductance value. FIG. 22 is an explanatory diagram (a) and (b) for comparing the opening widths of teardrop-shaped and annular annular members, and a table (c) for comparing the characteristics.

Hereinafter, first, the gapless magnetic core 10 according to the present invention will be described with reference to the drawings, and then an embodiment of the coil device 50 using the gapless magnetic core 10 will be described.

FIG. 1 is a plan view of a gapless magnetic core 10 according to an embodiment of the present invention. The gapless magnetic core 10 includes a main body 30 with a notch 31 formed in part and a segment 40 that fits into the notch 31 of the main body 30.

As shown in FIGS. 1 and 2, the segment 40 and the cutout portion 31 of the main body 30 from which the segment 40 is cut out have shapes in which the contact surfaces approach the inner peripheral surface of the main body 30, that is, approximately The inner peripheral surface of the segment 40 has a fan shape, and the magnetic body 21 protrudes inward (protrusion amount S) from the inner peripheral surface of the main body 30.

The gapless magnetic core 10 having the above-described configuration can be manufactured in the following manner.

First, as shown in FIG. 3, the annular member 20 including the magnetic body 21 is produced.
As shown in the sectional view of FIG. 4, the illustrated annular member 20 is obtained by covering the outer periphery of a magnetic body 21 made of a magnetic material with an insulating resin coating portion 22. In addition, the resin coating | coated part 22 should just be provided as needed, and can also form the annular member 20 only with the magnetic body 21. FIG.

4 has a substantially rectangular cross section of the magnetic body 21, the cross section of the magnetic body 21 may be circular, elliptical, or the like.

The shape of the annular member 20 may be a teardrop shape, an annular shape, an elliptical shape, an oval shape, a rectangular shape, or the like. FIG. 3 shows a teardrop-shaped annular member 20, and the annular member 20 connects one end of the linear first straight portion 23 and the second straight portion 24 at a substantially right angle with a curved portion 25 having a small curvature radius, These other ends are connected by an arc portion 26 having a large curvature radius.

Examples of magnetic materials used for the magnetic body 21 include iron-based, iron-silicon-based, iron-aluminum-silicon-based, iron-nickel-based materials, iron-based and Co-based amorphous materials, and the like. The magnetic body 21 is formed by pressing or compacting a powder made of a magnetic material, a ferrite core formed by sintering a powder made of a magnetic material, and a thin plate made of a magnetic material. The laminated magnetic core can be made.

Among the above-mentioned various magnetic materials, it is preferable to adopt a green compact as the magnetic body 21. This is because the green compact has high dimensional accuracy and high design freedom.

On the other hand, when the magnetic body 21 made of a compacted body is cut using a cutting blade (grinding stone), the peripheral surface may collapse when the cutting blade is applied. Accordingly, it is preferable to obtain the annular member 20 by insert-molding the magnetic body 21 made of a compacted body with an insulating resin and forming the resin coating 22 on the outer periphery of the magnetic body 21. Thereby, it can prevent that the magnetic body 21 collapse | crumbles in the case of a cutting | disconnection. The annular member 20 can also be produced by a resin powder coating method.

As shown in FIGS. 3 and 5, the produced annular member 20 crosses the inner circumferential surface and the outer circumferential surface and approaches the inner circumferential direction of the annular member 20 and the second cutting portion 27 and the second cutting portion 27. Cutting is performed by the cutting unit 28. The 1st cutting part 27 and the 2nd cutting part 28 implement a cutting | disconnection so that it may approach toward the inner peripheral direction of the annular member 20, as shown in FIG. That is, if the angle formed by the first cutting part 27 and the second cutting part 28 is α, 0 ° <α ≦ 90 °. The reason for this will be described later.

The cutting of the annular member 20 can be performed with a rotating cutting blade or the like. As the cutting blade, a metal-bonded diamond grindstone can be exemplified. The annular member 20 is preferably cut by the

straight portions

23 and 24 in order to prevent the cutting blade from escaping.

When cutting the annular member 20, it is not possible to perform cutting with the cutting allowance 29 as zero, and as shown in FIG. 5, a cutting allowance 29 corresponding to the thickness of the cutting blade is required. That is, the segment 40 becomes smaller by the cutting

allowances

29 and 29 than the cutout portion 31 of the main body 30 where the annular member 20 is cut and the segment 40 is cut. In order to reduce the cutting allowance 29, it is desirable to reduce the thickness of the cutting blade. For example, it is preferable to use a cutting blade having a blade thickness of 0.5 mm to 1.2 mm or a blade thickness thinner than 0.7 mm.

When the annular member 20 has a teardrop shape as shown in FIG. 3 described above, the first straight portion 23 or the second straight portion 24 is cut at least one of the first cut portion 27 or the second cut portion 28. The other cutting of the first cutting portion 27 or the second cutting portion 28 is preferably performed between the bent portion 25 and the end of the first straight portion 23 or the second straight portion 24.

As a result, as shown in FIG. 6, a wide opening width 36 for inserting the air-core coil 51 (FIG. 7, etc., which will be described later) can be secured in the cutout portion 31 of the main body 30 from which the segment 40 is cut out. it can. The opening width 36 will be described in detail in the fourth embodiment.

As shown in FIG. 6, the main body 30 cut out of the segment 40 includes a main body side first end surface 32 cut by the first cutting portion 27 and a main body side second end surface 33 cut by the second cutting portion 28. The cut-out segment 40 is formed between the first end surface 32 on the main body side and the second end surface 33 on the main body side. It is a letter-shaped member. The notch 31 has the main body side first end surface 32 and the main body side second end surface 33 approaching in the inner circumferential direction, and the angle formed by the main body side first end surface 32 and the main body side second end surface 33 is The angle α is the same as the angle formed by the first cutting portion 27 and the second cutting portion 28 toward the inner peripheral side of the annular member 20.

When the air-core coil 51 is inserted into the main body 30 as will be described later, in order to facilitate the insertion of the air-core coil 51, an end face (for example, a first end face on the main body side) on the insertion side of the air-core coil 51 of the main body 30 is used. 32), it is desirable to cut so that the front-end | tip of the main body 30 continuous with an end surface may become flat. In addition, the end surface opposite to the end surface (for example, the main body-side second end surface 33) has the notch 31 in FIG. It is desirable to form it in parallel to (indicated by an arrow in FIG. 7).

Similarly, as shown in FIG. 6, the segment 40 also has a segment-side first end face 42 cut by the first cutting portion 27 and a segment-side second end face 43 cut by the second cutting portion 28. The segment-side first end face 42 and the segment-side second end face 43 are substantially fan-shaped members that approach toward the inner circumferential direction. The angle formed by the segment side first end surface 42 and the segment side second end surface 43 of the segment 40 is the same as the angle formed by the first cutting portion 27 and the second cutting portion 28 toward the inner peripheral side of the annular member 20. It is.

The obtained segment 40 is pushed into the notch 31 of the main body 30 from the outer peripheral side and fixed, so that the notch 31 is backfilled and the gapless magnetic core 10 can be obtained.

The segment 40 is fixed to the main body 30 by bonding the main body side first end face 32 and the segment side first end face 42, the main body side second end face 33 and the segment side second end face 43, or the main body 30. And the segment 40 can be easily clamped.

When the segment 40 is cut out from the annular member 20 with the cutting blade, the cutting allowance 29 is required. Therefore, the segment 40 is pushed into the cutout portion 31 of the main body 30, and the main body side first end face 32 and the segment side first end face 42 are When the main body side second end surface 33 and the segment side second end surface 43 are brought into close contact with each other, the segment 40 is cut out by the thickness of the cutting

allowances

29 and 29 as shown in FIG. 1 and the enlarged sectional view 2. It enters the inside of the portion 31 and protrudes by an amount of protrusion S toward the inner peripheral side of the main body 30.

However, the segment 40 is pushed in until the main body side first end face 32 and the segment side first end face 42 and the main body side second end face 33 and the segment side second end face 43 are in close contact with each other in the pushing direction which is the width direction of the main body 30. Therefore, fine adjustment of the pushing amount of the segment 40 with respect to the notch 31 is unnecessary. That is, since it is only necessary to adjust the position of the segment 40 only in the height direction with respect to the notch 31, the gapless magnetic core 10 can be manufactured very easily.

In the manufactured gapless magnetic core 10, the magnetic flux passing through the magnetic body 21 takes a magnetic path on the inner peripheral side of the magnetic body 21 having the shortest magnetic path length, and the magnetic flux density is highest. In the present invention, as shown in FIG. 2, the magnetic path M on the inner peripheral side of the notch 31 of the main body 30 is secured to the segment 40 side without a gap. It can be seen that even if the cross-sectional area is lost, the substantial reduction of the cross-sectional area is small, stable inductance characteristics can be exhibited, and magnetic characteristics and the like are hardly deteriorated.

In addition, since the segment 40 is cut out from the main body 30, the main body 30 and the segment 40 have the same magnetic characteristics and the like. Therefore, extremely stable magnetic characteristics and the like can be exhibited as compared with the case where the segment is formed from another member.

Further, since the segment 40 cut out from the annular member 20 is returned to the cutout portion 31 of the main body 30, the step of forming the segment from another member can be eliminated, and in addition, the loss of raw materials is almost all. Therefore, the production efficiency can be increased as much as possible.

A method for manufacturing the coil device 50 using the gapless magnetic core 10 will be described.
First, after cutting out the segment 40 from the annular member 20 (FIG. 6), as shown in FIGS. 7 to 10, an air-core coil 51 in which a conducting wire is wound in advance from the notch 31 is inserted into the main body 30. The air-core coil 51 is manufactured by winding in accordance with the outer peripheral shape of the main body 30. And after inserting the air-core coil 51 in the main body 30, as shown in FIG.11 and FIG.12, the segment 40 is pushed and fixed to the notch part 31 of the main body 30 in the same way as the above, and a coil apparatus is carried out. 50 is produced.

Like the gapless magnetic core 10 of the present invention, the manufactured coil device 50 has no gap, and since the inner circumferential side magnetic path M passing through the magnetic body 21 and a substantial cross-sectional area are secured, the coil device 50 is stable. Magnetic properties and the like. Moreover, it has the various effects mentioned above.

By the way, in the gapless magnetic core 10 and the coil device 50, it is preferable that the angle α formed by the first cutting part 27 and the second cutting part 28 is 0 ° <α ≦ 90 °. In the embodiment of FIG. 1, the angle α is 60 °. 13 shows an embodiment in which the angle α is 75 °, FIG. 14 shows an angle α of 45 °, FIG. 15 shows an angle α of 30 °, and FIG. 16 shows an angle α of 20 °.

As described above, the lower limit of the angle α formed by the first cutting part 27 and the second cutting part 28 is set to be greater than 0 °, that is, the first cutting part 27 and the second cutting part 28 are not parallel to each other. However, referring to FIG. 1 and FIGS. 13 to 16 described above, it can be seen that as the angle α decreases, the protruding amount S of the segment 40 toward the inner peripheral side increases. As a result, when the protruding amount S increases, the facing area P between the magnetic body 21 of the main body 30 and the magnetic body 21 of the segment 40 decreases, the cross-sectional area is narrowed, and the magnetic characteristics and the like may be degraded.

When the angle α reaches 0 °, a gap corresponding to the cutting allowance generated by the first cutting blade and the second cutting blade is formed between the main body 30 and the segment 40, and the notch 31 has a segment. Even if 40 is inserted, both the first end faces 32 and 42 and the second end faces 33 and 43 cannot be brought into contact with each other at the same time.

For this reason, the angle α formed by the first cutting portion 27 and the second cutting portion 28 is preferably 20 ° or more, and more preferably 30 ° or more. The reason will be described in the examples.

The upper limit of the angle α formed by the first cutting part 27 and the second cutting part 28 is desirably 90 °. Although it is possible to form the segment 40 having an angle α exceeding 90 °, the segment 40 itself increases as the angle α increases, and the stroke of the air-core coil 51 that can be inserted becomes shorter, resulting in magnetic characteristics. This is because there is a concern that the above may decrease.
Desirably, the upper limit of the angle α formed by the first cutting part 27 and the second cutting part 28 is 75 °.

As described above, it is desirable to use a thin cutting blade for cutting the annular member 20 so that the cutting allowance 29 is thin. The thicker the cutting allowance 29, the larger the protruding amount S of the segment 40 toward the inner peripheral side, the smaller the facing area P between the magnetic body 21 of the main body 30 and the magnetic body 21 of the segment 40, and the narrower the magnetic path. This is because the magnetic characteristics and the like are deteriorated.

In order to secure the magnetic path M, it is desirable that the facing area P between the magnetic bodies 21 of the main body 30 and the segment 40 be 50% or more of the cross-sectional area C of the magnetic body 21 (see FIG. 2). More desirably, the facing area P is 80% or more of the cross-sectional area C.

In the embodiment shown in FIGS. 7 to 12, the resin coating portion 22 is formed with one end face 28 of the main body 30 and

protrusions

34 and 44 that are to be prevented from being removed from the segment 40, respectively. When the air-core coil 51 is inserted from the one end surface 27 of the main body 30, the air-core coil 51 hits the retaining member 34, so that it can be prevented from falling off. Further, after the coil device 50 is manufactured, the retaining

cores

34 and 44 can prevent the air-core coil 51 from moving on the gapless magnetic core 10, and the lead terminal of the air-core coil 51 is positioned. be able to.

Further, by forming the retaining

members

34 and 44, it can be used as a mark for inserting a cutting blade when the annular member 20 shown in FIG. 5 is cut.

17 and 18 show different embodiments of the retaining member 34, and the retaining member 34 of the main body 30 is provided so as to project both on the inner peripheral side and the outer peripheral side. 17 and 18, the protruding amount S of the segment 40 is the same. This is because the cutting allowance 29 in FIG. 17 is 0.5 mm and the cutting allowance 29 in FIG. This is because the thickness is 7 mm. 17 and 18 that the protrusion amount S increases as the cutting allowance 29 increases.

A plurality of green compacts were produced from Sendust powder (composition: Fe—Si—Al alloy) as the magnetic body 21, and an annular member 20 in which the resin coating portion 22 was formed by insert molding was obtained. The magnetic body 21 has a teardrop shape having a cross section with a width of 9.8 mm and a height of 25 mm, an inner peripheral length of 84 mm, and an average magnetic path length of 114 mm. Moreover, the thickness of the resin coating part 22 is 0.6 mm.

<First embodiment: Comparison of DC superposition characteristics>
From this annular member 20, the angle α formed by the first cutting portion 27 and the second cutting portion 28 is 0 ° (comparative example: the first cutting portion and the second cutting portion are parallel), 20 ° (invention example 11), The segment 40 was cut out to be 30 ° (Invention Example 12), 45 ° (Invention Example 13), and 75 ° (Invention Example 14). A rotary blade having a blade thickness of 0.7 mm was used as the cutting blade. The cutting allowance 29 is larger than the blade thickness of the cutting blade, and is 0.75 mm respectively.

The air core coil 51 was inserted into the main body 30 cut out of the segment 40, the segment 40 was backfilled and fixed, and the coil device 50 was produced. For the comparative example, the segment 40 was adjusted so that the two gaps had the same width.

For each of the obtained coil devices 50, a DC bias current of 0 to 24A was passed and the DC superposition characteristics were examined. The results are shown in FIG. Referring to the figure, it can be seen that the invention example has a higher inductance value than the comparative example. In particular, when the DC bias current is in the range of 0 A to 12 A, all exhibit higher inductance values than the comparative example.

This is because the main body side first end face 32 and the segment side first end face 42 and the main body side second end face 33 and the segment side second end face 43 are pushed by pushing the segment 40 into the notch 31 without forming a gap. This is because the contact is made without a gap. On the other hand, it can be seen that in the comparative example, the gap due to the cutting allowance was formed between the main body and the segment, so that the magnetic flux leaked and a high inductance value could not be secured.

When comparing the inventive examples, the inventive example 4 in which the angle α is 75 ° exhibits the highest inductance value, and the inductance value decreases as the angle α decreases. This is because the larger the angle α is, the smaller the protrusion amount S of the segment 40 toward the inner peripheral side is, the opposing area between the main body side first end surface 32 and the segment side first end surface 42, the main body side second end surface 33 and the segment side first. This is because the opposing area of the two end faces 43 can be increased and the magnetic path M can be secured.

<Second embodiment: Comparison of initial inductance values>
Further, the angle α formed by the first cutting portion 27 and the second cutting portion 28 from the annular member 20 is 0 ° (comparative example: the first cutting portion and the second cutting portion are parallel), 10 ° (Invention Example 21). ), 20 ° (Invention Example 22), 30 ° (Invention Example 23), 45 ° (Invention Example 24), and 75 ° (Invention Example 25). These initial inductance values were measured. The results are shown in FIG.

As shown in FIG. 20, when the invention example and the comparative example are compared, the invention example 22 in which the angle α is 20 ° has an initial inductance value improved by about 14% compared to the comparative example, and the angle α is 75. Inventive Example 25, which is °, was able to improve the initial inductance value by about 29% compared to the comparative example.

On the other hand, from FIG. 20, Invention Example 21 in which the angle α is 10 ° has an initial inductance value substantially equal to that of the comparative example. This is because a sufficient magnetic path could not be secured as a result of an increase in the projecting amount S of the segment 40 toward the inner periphery. However, in the present invention, a magnetic path M without a gap can be ensured simply by pushing the segment 40 into the notch 31, so that even when the angle α is 10 °, when the plurality of coil devices 50 are manufactured, There is an advantage that a certain inductance value can be secured. On the other hand, since it is difficult to adjust the width of the two gaps in the comparative example, it is difficult to obtain a constant inductance value when a plurality of coil devices are manufactured, and the invention example is superior.

Further, comparing the inventive examples, it can be seen from FIG. 20 that the initial inductance value is linearly decreased in the range where the angle α is 75 ° to 30 °. However, when the angle α is changed from 30 ° to 20 °, the decrease amount of the initial inductance value is increased, and when the angle α is changed from 20 ° to 10 °, the initial inductance value is greatly reduced.

This is because as the angle α decreases, the protrusion amount S to the inner peripheral side of the segment 40 increases, and as a result, the magnetic path M on the inner peripheral side of the gapless magnetic core 10 is ensured. This is because the opposing area of the segment 40 to the magnetic body 21 is reduced, and a sufficient magnetic path cannot be secured as a whole.

From the above examples, it can be seen that the lower limit of the angle α formed by the first cutting portion 27 and the second cutting portion 28 is preferably 20 ° or more, and more preferably 30 ° or more.

It can also be seen that the upper limit of the angle α is preferably 90 ° or less. On the other hand, when the angle α is increased, the segment 40 is increased and the stroke of the air-core coil 51 that can be inserted into the main body 30 is shortened. Therefore, the upper limit of the angle α is more preferably 75 ° or less. .

<Third embodiment: Comparison of opposing area P of main body and segment and initial inductance value>
In order to examine the change of the initial inductance value due to the opposing area P with respect to the cross-sectional area C of the main body 30 and the segment 40, the angle α formed by the first cutting portion 27 and the second cutting portion 28 from the annular member 20 is 20 ° (invention). Example 31), segment 40 was cut out to be 30 ° (Invention Example 32), 45 ° (Invention Example 33), 60 ° (Invention Example 34), and 75 ° (Invention Example 25). They were prepared and their initial inductance values were measured. The results are shown in FIG.

Referring to FIG. 21, it can be seen that the initial inductance value increases as the ratio of the opposed area P to the cross-sectional area C increases.

<Fourth embodiment: Comparison of opening widths for inserting air-core coils>
As shown in FIGS. 22A and 22B, the size of the segment 40 necessary for forming the notch 31 having the same opening width 36 in which the annular member 20 has a teardrop shape and an annular shape (toroidal core). Compared. The teardrop-shaped annular member 20 (FIG. 22A) was cut so that the first cutting portion 27 was positioned at the curved portion 25 and the second cutting portion 28 was positioned at the second straight portion 24.

Referring to the drawing, in the teardrop-shaped annular member 20, the size of the segment 40 to be cut out is smaller than that of the annular annular member 20. This is because the notch 31 is formed so as to include the curved portion 25 having a small radius of curvature.

FIG. 22 (c) shows a table comparing characteristics of the teardrop-shaped and annular annular member 20. Referring to the table, the teardrop-shaped annular member 20 can reduce the stroke of the air-core coil that can be inserted into the main body 30 because the segment 40 can be made smaller than the annular annular member 20. Can be long.

Further, regarding the cutting operation at the first cutting portion 27 and the second cutting portion 28, the teardrop-shaped annular member 20 needs to chuck the annular member 20 with a jig or the like at the time of cutting. Since a large area can be stably chucked with reference to 23 or 24 and cutting can be performed, positioning is easy. In addition, since the cutting portion 28 is positioned on the straight portion 24, the cutting blade can be orthogonally cut with respect to the straight portion 28, so that the cutting blade can be cut off easily and the cutting operation can be easily performed. .

Therefore, when the teardrop-shaped annular member 20 and the annular annular member 20 are compared, it can be seen that the present invention is particularly suitable for application to the teardrop-shaped annular member 20.

Furthermore, regarding the workability when returning the segment 40 to the main body 30, in the case of the teardrop-shaped annular member 20, it is only necessary to adjust the height and then push the segment 40 into the notch 31. In the case of the annular member 20, in addition to the adjustment in the height direction, the adjustment in the two directions is performed so that the first end surfaces 32 and 42 and the second end surfaces 33 and 43 are in contact with each other. Is required. For this reason, the teardrop-shaped annular member 20 is superior in positioning accuracy and workability.

The above description is for explaining the present invention, and should not be construed as limiting the invention described in the claims or limiting the scope thereof. Further, the configuration of each part of the present invention is not limited to the above-described embodiment, and various modifications can be made within the technical scope described in the claims.

For example, when a plurality of annular members 20 having the same shape are produced, the segment 40 can be returned to another main body 30 without returning to the main body 30 from which the segment 40 is cut out. The segment 40 can also be arranged such that the segment-side first end face 42 abuts on the main body-side second end face 33 and the segment-side second end face 43 abuts on the main body-side first end face 32.

DESCRIPTION OF SYMBOLS 10 Gapless magnetic core 20 Annular member 27 1st cutting part 28 2nd cutting part 30 Main body 31 Notch part 32 Main body side 1st end surface 33 Main body side 2nd end surface 40 Segment 42 Segment side 1st end surface 43 Segment side 2nd end surface 50 Coil device 51 Air-core coil α Angle formed by the first cutting portion and the second cutting portion S Projecting amount on the inner peripheral side of the segment

Claims

An annular member including an annular magnetic body made of a magnetic material is cut at a first cutting portion and a second cutting portion that cross the outer peripheral surface and the inner peripheral surface and approach each other toward the inner peripheral direction of the annular member;
A main body having a main body side first end surface cut by the first cutting portion and a main body side second end surface cut by the second cutting portion;
Obtaining a segment having a segment-side first end face cut by the first cutting part and a segment-side second end face cut by the second cutting part;
In the notch formed between the main body side first end surface and the main body side second end surface, the main body side first end surface and the segment side first end surface, the main body side second end surface and the segment side first Formed by pushing the segment so that the two end faces abut,
Gapless magnetic core.
The segment has an inner peripheral end surface protruding inward from the inner peripheral surface of the main body.
The gapless magnetic core according to claim 1.
The annular member connects one end of the linear first straight part and the second straight part at a substantially right angle with a curved part having a small radius of curvature, and the other end of the first straight part and the second linear part is curved. It has a teardrop shape connected by a circular arc part with a large radius,
Cutting at least one of the first cutting portion or the second cutting portion is performed on the first straight portion or the second straight portion,
The gapless magnetic core according to claim 1 or 2.
The other cutting of the first cutting part or the second cutting part is performed between the bent part and the end of the first cutting part or the second straight part.
The gapless magnetic core according to claim 3.
The angle formed by the first cut portion and the second cut portion is 90 ° or less.
The gapless magnetic core according to claim 1.
The angle formed by the first cut portion and the second cut portion is 75 ° or less.
The gapless magnetic core according to claim 1.
The angle formed by the first cutting part and the second cutting part is 20 ° or more.
The gapless magnetic core according to any one of claims 1 to 6.
The main body side first end surface and the segment side first end surface, the main body side second end surface and the segment side second end surface are fixed by an adhesive,
The gapless magnetic core according to any one of claims 1 to 7.
The annular member includes an annular magnetic body and an insulating resin coating that covers the magnetic body.
The gapless magnetic core according to any one of claims 1 to 8.
The magnetic body is a compacted body of magnetic material, and the resin coating is formed by an insert molding method or a resin powder coating method.
The gapless magnetic core according to claim 9.
The gapless magnetic core according to any one of claims 1 to 10, wherein an air core coil wound in advance from the notch is inserted into the gapless magnetic core, and then the segment is pushed into the notch. Coil device.
An annular member including an annular magnetic body made of a magnetic material is cut at a first cutting portion and a second cutting portion that cross the outer peripheral surface and the inner peripheral surface and approach each other toward the inner peripheral direction of the annular member;
A main body having a main body side first end surface cut by the first cutting portion and a main body side second end surface cut by the second cutting portion;
Obtaining a segment having a segment-side first end face cut by the first cutting part and a segment-side second end face cut by the second cutting part;
An air core coil wound in advance is inserted into a notch formed between the main body side first end surface and the main body side second end surface, and the main body side first end surface and the segment side first end surface, Formed by pushing the segment so that the main body side second end surface and the segment side second end surface abut,
The manufacturing method of the coil apparatus characterized by the above-mentioned.