JP2017135292A - Reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor capable of reducing copper loss due to leakage flux. A reactor 1 includes a core 2, a covering member 4, and a conducting wire 5. The core 2 is made of a magnetic material and has a plurality of blocks 20 arranged through a magnetic gap 3. The covering member 4 is made of a non-magnetic material having electrical insulation and covers the magnetic gap 3. The conducting wire 5 is coiled around at least one block 20 out of the plurality of blocks 20 and the covering member 4. [Selection diagram] Fig. 1

Description

  The present invention relates to a reactor.

  Conventionally, there is a reactor that uses an iron core having an air gap (magnetic gap) in a magnetic path as a magnetic core (see, for example, Patent Document 1).

JP 2015-46587 A

  Copper loss occurs due to magnetic flux leaking from the magnetic gap (leakage magnetic flux) interlinking the conductive wires. In this field, reduction of copper loss is desired.

  This invention is made | formed in view of the said reason, The objective is to provide the reactor which can reduce the copper loss by a leakage magnetic flux.

  The reactor of the present invention is composed of a magnetic material, a core having a plurality of blocks arranged via a magnetic gap, a covering member that is composed of a nonmagnetic material having electrical insulation and covers the magnetic gap, It is characterized by comprising at least one block among a plurality of blocks and a conducting wire wound around the covering member in a coil shape.

  The reactor of the present invention has an effect that copper loss due to leakage magnetic flux can be reduced.

FIG. 1A is a perspective view of a state where a conducting wire is removed from a reactor according to an embodiment of the present invention. FIG. 1B is a perspective view of the reactor. 2 is a cross-sectional view taken along line AA in FIG. 1B. FIG. 3 is an analysis model of electromagnetic field simulation in the reactor described above. FIG. 4 is an analysis result of the electromagnetic field simulation in the reactor described above. FIG. 5 is an analysis model of electromagnetic field simulation in the reactor of the comparative example. FIG. 6 is an analysis result of the electromagnetic field simulation in the reactor of the comparative example. FIG. 7 is a cross-sectional view of a reactor according to a first modification of one embodiment of the present invention. FIG. 8 is a cross-sectional view of a reactor according to a second modification of the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments generally relate to a reactor, and more particularly to a reactor having a core around which a conductor is wound. In addition, each figure demonstrated in the following embodiment is a typical figure, and the dimension ratio of each component does not necessarily reflect an actual dimension ratio.

(Embodiment)
FIG. 1A is a perspective view of the reactor 1 of the present embodiment with the conductive wire 5 removed, and FIG. 1B is a perspective view of the core 2 wound with the conductive wire 5, and FIG. 2 is a cross-sectional view of FIG. . The reactor 1 of this embodiment is a magnetic core coil, and is used, for example, as a circuit element of a power conversion device that converts DC power into AC power. In addition, the usage application of the reactor 1 is not limited to the power conversion device, and may be used for circuit elements of other devices.

  The reactor 1 of the present embodiment includes a core 2, a covering member 4, and a conductive wire 5.

  The core 2 is made of a magnetic material (for example, ferrite or the like), and a plurality of blocks 20 form a magnetic circuit. The plurality of blocks 20 includes four columnar blocks 21a, 21b, 21c, and 21d formed in a columnar shape, and two rectangular blocks 22a and 22b formed in a rectangular shape. In addition, when the four cylindrical blocks 21a, 21b, 21c, and 21d are not distinguished, they are called cylindrical blocks 21. When the two rectangular blocks 22a and 22b are not distinguished, they are called rectangular blocks 22. When the cylindrical block 21 and the rectangular block 22 are not distinguished, they are referred to as a block 20.

  The columnar block 21a and the columnar block 21b are arranged side by side in the first direction D1 so that their end faces face each other. The cylindrical block 21a and the cylindrical block 21b are bonded to each other with an adhesive 30 (for example, an epoxy-based adhesive), and constitute a cylindrical body 210a around which the conductive wire 5 is wound in a coil shape. Yes. In addition, the columnar block 21c and the columnar block 21d are arranged side by side in the first direction D1 so that their end faces face each other. The columnar block 21c and the columnar block 21d are bonded to each other with an adhesive 30 to form a columnar body 210b around which the conductive wire 5 is wound in a coil shape. The body part 210a and the body part 210b are arranged side by side in a second direction D2 orthogonal to the first direction D1. When the body portions 210a and 210b are not distinguished, they are referred to as the body portion 210.

  The rectangular body block 22a is disposed on one side in the first direction D1 with respect to each of the body portions 210a and 210b. The rectangular block 22a has an adhesive 30 (an end surface of the cylindrical block 21c) and an end surface of the trunk portion 210a (an end surface of the cylindrical block 21a) and an end surface of the trunk portion 210b (an end surface of the cylindrical block 21c) on one surface intersecting the first direction D1. 2). Moreover, the rectangular body block 22b is arrange | positioned with respect to each of trunk | drum 210a, 210b at the other side of the 1st direction D1. The rectangular body block 22b has an adhesive 30 (an end surface of the cylindrical block 21d) and an end surface of the trunk portion 210a (an end surface of the cylindrical block 21b) and an end surface of the trunk portion 210b (an end surface of the cylindrical block 21d) on one surface intersecting the first direction D1. 2).

  The core 2 forms a magnetic circuit by bonding each block 20 to the block 20 adjacent in the first direction D1 with an adhesive 30. Accordingly, each block 20 is arranged apart from the adjacent block 20 by the thickness of the adhesive 30 (for example, about 30 μm to 40 μm). That is, the adhesive 30 is included in the magnetic circuit formed by the core 2 as a magnetic path. Since the adhesive 30 has a lower magnetic permeability than the core 2 (each block 20), the adhesive 30 becomes the magnetic gap 3. The “magnetic gap” in the present embodiment indicates a magnetic path having a magnetic permeability lower than that of the core 2 (each block 20), in other words, having a larger magnetic resistance than that of the core 2 (each block 20).

  The covering member 4 is made of a nonmagnetic material (eg, phenol resin) having electrical insulation. The covering member 4 is formed in a circular frame shape, in other words, in a ring shape, and the inner diameter is substantially the same as the diameter of the cylindrical block 21. Moreover, the covering member 4 has a rectangular cross section 41 (see FIG. 2) that intersects the circumferential direction. The covering member 4 is fitted to the cylindrical block 21 so as to cover the magnetic gap 3 (adhesive 30) over the entire circumference. The reactor 1 of the present embodiment is formed with six magnetic gaps 3 and includes six covering members 4 so as to individually cover each magnetic gap 3. If necessary, the magnetic gap 3 between the two cylindrical blocks 21 is referred to as a magnetic gap 3a, and the covering member 4 that covers the magnetic gap 3a is referred to as a covering member 4a. The magnetic gap 3 between the cylindrical block 21 and the rectangular block 22 is called a magnetic gap 3b, and the covering member 4 that covers the magnetic gap 3b is called a covering member 4b.

  The covering member 4a covers the magnetic gap 3a by being disposed across the two cylindrical blocks 21 arranged in the first direction D1. The covering member 4a is preferably arranged so that the central portion in the first direction D1 faces the magnetic gap 3a.

  The covering member 4b covers the magnetic gap 3b by being arranged so that a part thereof protrudes from the end face of the cylindrical block 21 to the rectangular body block 22 side.

  The conducting wire 5 is made of, for example, copper or the like, and is wound around each trunk portion 210 with the covering member 4 attached thereto in a coil shape. In other words, the conducting wire 5 is wound around each columnar block 21 and each covering member 4 in a coil shape.

  As shown in FIG. 2, since the covering member 4 is disposed so as to cover the magnetic gap 3, the conducting wire 5 is disposed outside the covering member 4. Therefore, the conducting wire 5 is arranged away from the magnetic gap 3 according to the dimension of the cross section 41 of the covering member 4.

  Next, the copper loss in the reactor 1 of this embodiment is demonstrated using FIGS. When a current flows through the conducting wire 5, a magnetic flux is generated in the magnetic circuit including each block 20 and each magnetic gap 3. Further, a copper loss occurs when the magnetic flux leaking from the magnetic gap 3 (leakage magnetic flux) links the conductive wire 5. As the frequency of the current flowing through the conducting wire 5 increases, the leakage magnetic flux increases and copper loss is likely to occur. The distribution of copper loss in the conducting wire 5 can be analyzed, for example, by electromagnetic field simulation.

  FIG. 3 is an analysis model of electromagnetic field simulation in the reactor 1 of the present embodiment. FIG. 4 is an analysis result of the electromagnetic field simulation in the reactor 1 of the present embodiment. FIG. 5 is an analysis model of electromagnetic field simulation in the reactor 100 of the comparative example. The reactor 100 of the comparative example is different from the reactor 1 of the present embodiment in that the covering member 4 is not provided. FIG. 6 is an analysis result of an electromagnetic field simulation in the reactor 1A of the comparative example.

  In the analysis models shown in FIGS. 3 and 5, an area obtained by dividing reactor 1, 100 into ¼ due to the symmetry of reactor 1, 100 is an analysis area. Specifically, the analysis model is such that the reactor 1, 100 is 1/2 in the second direction D2, and 1/3 in the third direction D3 (see FIGS. 1A and 1B) orthogonal to the first direction D1 and the second direction D2. An area divided into two is used as an analysis area. In the analysis model, it is assumed that the conducting wire 5 has a diameter of 2.4 mm, the number of turns around the body portion 210 is 38 turns, and an alternating current of 20 kHz flows. The analysis results shown in FIGS. 4 and 6 show the distribution of copper loss in the conductive wire 5 in shades, where the dark region is a region with a large copper loss and the light region is a region with a small copper loss.

  Since the leakage magnetic flux leaks from the magnetic gap 3, the closer to the magnetic gap 3, the larger the copper loss occurs. Since the reactor 100 of the comparative example does not include the covering member 4, the conducting wire 5 is also located in the vicinity of the magnetic gap 3. Therefore, as shown in FIG. 6, in the reactor 100 of the comparative example, a large copper loss occurs at a site in the vicinity of the magnetic gap 3 in the conducting wire 5.

  On the other hand, in the reactor 1 of the present embodiment, the conducting wire 5 is not positioned in the vicinity of the magnetic gap 3 by the covering member 4 covering the magnetic gap 3, in other words, the conducting wire 5 is arranged away from the magnetic gap 3. That is, the covering member 4 restricts the position of the conducting wire 5 so that the conducting wire 5 is not disposed in a space where the leakage magnetic flux is large. Thereby, since the leakage magnetic flux which links the conducting wire 5 is suppressed, as shown in FIG. 4, FIG. 6, the reactor 1 of this embodiment has reduced copper loss compared with the reactor 100 of the comparative example. .

  Next, the effect of the reactor 1 of this embodiment is demonstrated.

  The reactor 1 of this embodiment includes a core 2, a covering member 4, and a conductive wire 5. The core 2 is made of a magnetic material and has a plurality of blocks 20 arranged with the magnetic gap 3 interposed therebetween. The covering member 4 is made of a nonmagnetic material having electrical insulation and covers the magnetic gap 3. The conducting wire 5 is wound around at least one block 20 of the plurality of blocks 20 and the covering member 4 in a coil shape.

  With the above configuration, in the reactor 1 of the present embodiment, since the conducting wire 5 is arranged away from the magnetic gap 3 by the covering member 4 that covers the magnetic gap 3, it is possible to reduce the copper loss due to the leakage magnetic flux from the magnetic gap 3. It becomes.

  Moreover, in the reactor 1 of this embodiment, the coating | coated member 4 is formed in frame shape, and the cross section 41 which cross | intersects the circumferential direction is a rectangular shape. With the above configuration, the outer peripheral surface of the block 20 (cylindrical block 21) around which the conductive wire 5 is wound and the outer peripheral surface of the covering member 4 can be made parallel, and winding deviation of the conductive wire 5 can be suppressed. .

  In addition, the copper loss can be adjusted by appropriately setting the size of the covering member 4, specifically, the dimension of the cross section 41 of the covering member 4 according to the amount of current flowing through the conductor 5, the frequency of the current, and the like. It becomes possible.

  In addition, in the reactor 1 of this embodiment, the trunk | drum 210 around which the conducting wire 5 is wound is comprised by the two blocks 20 (cylindrical block 21), However, it is comprised by the three or more blocks 20 (cylindrical block 21). It may be. Or the trunk | drum 210 may be comprised by the one block 20 (cylindrical block 21).

  Moreover, although the coating | coated member 4 in the reactor 1 of this embodiment is comprised by the frame-shaped member fitted by the block 20 (columnar block 21) so that the magnetic gap 3 may be covered, it is not restricted to this structure. For example, the covering member 4 may be composed of a belt-like member (tape) that is wound around the block 20 (cylindrical block 21) so as to cover the magnetic gap 3.

  Next, a modified example of the reactor 1 will be described.

(First modification)
In the reactor 1A of the first modification shown in FIG. 7, the shape of the covering member 4A is different from the shape of the covering member 4 in the reactor 1 of the above embodiment. As shown in FIG. 7, the covering member 4A in the reactor 1A of the present modification is formed in a frame shape, and the outer side 42A in the cross section 41A intersecting with the circumferential direction has an arc shape.

  Specifically, the covering member 4A (4aA) that covers the magnetic gap 3a between the two cylindrical blocks 21 has a cross section 41A (41aA) that intersects the circumferential direction in a semicircular shape. The covering member 4A (4bA) that covers the magnetic gap 3b between the cylindrical block 21 and the rectangular block 22 has a cross section 41A (41bA) that intersects the circumferential direction formed in a quarter circle (1/4 of a circle). Has been.

  The leakage magnetic flux leaks radially from the magnetic gap 3. Since the outer side 42A in the cross section 41A is formed in an arc shape in the covering member 4A in the reactor 1A of this modification, the covering member 4A is prevented from excessively restricting the position of the conductor 5. Thereby, it becomes possible to suppress the winding of the conducting wire 5 and to reduce the size of the reactor 1A.

(Second modification)
In the reactor 1B of the second modification shown in FIG. 8, the shape of the covering member 4A is different from the shape of the covering member 4 in the reactor 1 of the above embodiment and the covering member 4A of the reactor 1A in the first modification. As shown in FIG. 8, the covering member 4B in the reactor 1B of the present modification includes a spacer 44B that is interposed between the two blocks 20 and defines the magnetic gap length L1.

  Specifically, the covering member 4B includes a frame portion 43B that covers the magnetic gap 3, and a spacer 44B that is formed inside the frame portion 43B and interposed between the two blocks 20. The spacer 44B includes a plate portion 441B facing the end surfaces of the two blocks 20, and a plurality of protrusions 442B protruding from one surface and the other surface of the plate portion 441B. Each of the plurality of protrusions 442B is formed in a hemispherical shape. Each of the plurality of protrusions 442B contacts the block 20 adjacent in the first direction D1. The adhesive 30 is provided between the plate portion 441 and the block 20 so as to avoid the plurality of protrusions 442B, and bonds the plate portion 441 and the block 20 together. In the reactor 1 </ b> B of this modification, the adhesive 30 and the spacer 44 </ b> B having a lower magnetic permeability than the core 2 (each block 20) serve as the magnetic gap 3.

  With the above configuration, the dimension between the two blocks 20, in other words, the magnetic gap length L1 of the magnetic gap 3 is set to the dimension of the spacer 44B in the first direction D1 (the thickness of the plate portion 441 and the radius of the protrusion 442B × 2). Total). Thereby, since the dispersion | variation in the magnetic gap length L1 is suppressed, it becomes possible to suppress the dispersion | variation in the inductance of the reactor 1B.

  The above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment and each modification, and other embodiments than this embodiment and each modification are within the scope not departing from the technical idea of the present invention. Of course, various changes can be made according to the design and the like.

1, 1A, 1B Reactor 2 Core 20 Block 3 (3a, 3b) Magnetic gap 4 (4a, 4b), 4A (4aA, 4bA), 4B Cover member 41, 41A (41aA, 41bA) Cross section 42A Side 44B Spacer 5 Conductor L1 Magnetic gap length

Claims (4)

A core composed of a magnetic material and having a plurality of blocks arranged via a magnetic gap;
A covering member that is made of a nonmagnetic material having electrical insulation and covers the magnetic gap;
A reactor comprising: at least one block among the plurality of blocks; and a conductive wire wound around the covering member in a coil shape. The reactor according to claim 1, wherein the covering member is formed in a frame shape and has a rectangular cross section that intersects the circumferential direction. The reactor according to claim 1, wherein the covering member is formed in a frame shape, and an outer side in a cross section intersecting the circumferential direction has an arc shape. The reactor according to any one of claims 1 to 3, wherein the covering member includes a spacer that is interposed between two of the plurality of blocks and defines a magnetic gap length.