Reactor, magnetic core, converter, and power conversion device

Abstract

To provide a reactor the heat dissipation capability of which can be easily increased, and with which, while increasing the number of turns, it is easy to suppress an increase in size and a reduction in magnetic path area.SOLUTION: Provided is a reactor comprising a magnetic core having a core part that is constructed to a prismatic shape, and a coil having a first wound part that is disposed on the outer circumference of the core part and a second wound part that is disposed on the outer circumference of the first wound part. The first wound part is composed of a first winding that is wound in spiral form so as to follow the outer circumferential surface of the core part, and the second wound part is composed of a second winding that is wound so as to follow the outer circumferential surface of the first wound part. The first and second windings consist of a string of windings. The number of turns of the first wound part is fewer than the number of turns of the second wound part. The outer circumferential surface of the core part includes a first plane having a plurality of grooves that are aligned in the axial direction of the core part, with some of the first windings in each turn of the first wound part being arranged in each of the plurality of grooves.

Description

[Technical Field]

[0001] The present disclosure relates to a reactor, a magnetic core, a converter, and a power conversion device. [Background technology]

[0002] The reactor of Patent Document 1 includes a coil and a magnetic core. The coil has a pair of winding portions formed by spirally winding a wire. Each winding portion has a rectangular cylindrical shape. The magnetic core has a pair of inner core portions and a pair of outer core portions. Each inner core portion is disposed inside each winding portion. Each inner core portion has a rectangular columnar shape. Each outer core portion is disposed outside both winding portions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-219318 Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable to easily improve heat dissipation, and to increase the number of turns while suppressing an increase in reactor size and a reduction in magnetic path area.

[0005] The reactor of Patent Document 1 is manufactured as follows: A pair of winding portions is prepared. Each inner core portion is inserted into each winding portion. Both inner core portions and both outer core portions are fixed together. In order to insert each inner core portion into each winding portion, a gap is provided between the inner peripheral surface of each winding portion and the outer peripheral surface of each inner core portion. The provision of the gap makes it difficult to improve the heat dissipation performance of the inner core portion.

[0006] To increase the number of turns, it is possible to make each winding section a two-layer structure with an inner and outer layer rather than a single-layer structure. When the cross-sectional area of ​​the inner core section is constant, a reactor with a winding section with a two-layer structure will be larger than a reactor with a winding section with a single-layer structure. The cross-sectional area of ​​the inner core section is the area of ​​a cross section perpendicular to the axial direction of the inner core section. When the outer diameter of the winding section is constant, a reactor with a winding section with a two-layer structure will have a smaller cross-sectional area of ​​the inner core section than a reactor with a winding section with a single-layer structure, resulting in a reduced magnetic path area.

[0007] An object of the present disclosure is to provide a reactor that can easily improve heat dissipation and can easily increase the number of turns while suppressing an increase in size and a reduction in magnetic path area.An object of the present disclosure is to provide a magnetic core that can be used to construct a reactor that can easily improve heat dissipation and can easily increase the number of turns while suppressing an increase in size and a reduction in magnetic path area.An object of the present disclosure is to provide a converter including the reactor and a power conversion device including the converter. [Means for solving the problem]

[0008] The reactor of the present disclosure includes: a magnetic core having a core portion formed in a prismatic shape; a coil having a first winding portion disposed on an outer periphery of the core portion and a second winding portion disposed on an outer periphery of the first winding portion, The first winding portion is wound along the outer peripheral surface of the core portion. spirally It consists of a wound primary winding, the second winding portion is configured by a second winding wound along an outer peripheral surface of the first winding portion, the first winding and the second winding are a series of windings, the number of turns of the first winding portion is less than the number of turns of the second winding portion, an outer peripheral surface of the core portion includes a first plane having a plurality of grooves aligned in the axial direction of the core portion; A portion of the first winding in each turn of the first winding portion is disposed in each of the plurality of grooves.

[0009] The magnetic core of the present disclosure is It has a prismatic core, The outer peripheral surface of the core portion includes a first plane having a plurality of grooves aligned in the axial direction of the core portion.

[0010] The converter of the present disclosure includes the reactor of the present disclosure.

[0011] The power conversion device of the present disclosure includes the converter of the present disclosure. [Effects of the Invention]

[0012] The reactor of the present disclosure is easy to improve heat dissipation and to increase the number of turns while suppressing an increase in size and a reduction in magnetic path area. The magnetic core of the present disclosure is easy to build a reactor that is easy to improve heat dissipation and to increase the number of turns while suppressing an increase in size and a reduction in magnetic path area. The converter and power conversion device of the present disclosure have excellent heat dissipation properties without increasing in size. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic perspective view showing a reactor of the first embodiment. [Figure 2] FIG. 2 is a schematic exploded perspective view showing the reactor of the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is an enlarged view of area A in FIG. [Figure 5] FIG. 5 is an enlarged view showing another example of the groove and the first winding in the reactor of the first embodiment. [Figure 6] FIG. 6 is an enlarged view showing another example of the groove and the first winding in the reactor of the first embodiment. [Figure 7] FIG. 7 is an enlarged view showing a groove and a first winding in the reactor of the second embodiment. [Figure 8] FIG. 8 is an enlarged view showing a groove and a first winding in the reactor of the third embodiment. [Figure 9] FIG. 9 is an enlarged view showing a groove and a first winding in the reactor of the fourth embodiment. [Figure 10] FIG. 10 is an enlarged view showing a groove and a first winding in the reactor of the fifth embodiment. [Figure 11] FIG. 11 is an enlarged view showing another example of the groove and the first winding in the reactor of the fifth embodiment. [Figure 12] FIG. 12 is a schematic diagram showing the power supply system of a hybrid vehicle. [Figure 13] FIG. 13 is a circuit diagram showing an example of a power conversion device including a converter. DETAILED DESCRIPTION OF THE INVENTION

[0014] <<Description of Embodiments of the Present Disclosure>> First, embodiments of the present disclosure will be listed and described.

[0015] (1) A reactor according to one embodiment of the present disclosure includes: a magnetic core having a core portion formed in a prismatic shape; a coil having a first winding portion disposed on an outer periphery of the core portion and a second winding portion disposed on an outer periphery of the first winding portion, the first winding portion is configured by a first winding that is wound in a spiral shape along an outer peripheral surface of the core portion, the second winding portion is configured by a second winding wound along an outer peripheral surface of the first winding portion, the first winding and the second winding are a series of windings, the number of turns of the first winding portion is less than the number of turns of the second winding portion, an outer peripheral surface of the core portion includes a first plane having a plurality of grooves aligned in the axial direction of the core portion; A portion of the first winding in each turn of the first winding portion is disposed in each of the plurality of grooves.

[0016] The above-mentioned configuration (1) is more likely to improve heat dissipation than a conventional reactor. In the above-mentioned configuration (1), the first winding portion is arranged along the outer peripheral surface of the core portion, and a portion of the first winding in each turn of the first winding portion is arranged in each of a plurality of grooves provided in the core portion. That is, the above-mentioned configuration (1) is more likely to increase the contact area between the first winding and the core portion. On the other hand, in a conventional reactor, a gap is provided between the inner peripheral surface of the winding portion and the outer peripheral surface of the core portion. That is, in a conventional reactor, the winding portion and the core portion do not contact each other. Therefore, the above-mentioned configuration (1) is more likely to transfer heat from the coil to the core portion than a conventional reactor.

[0017] In the configuration (1) above, the number of turns can be increased by the coil having the first winding portion, and therefore the configuration (1) above is excellent in inductance.

[0018] In the configuration (1) above, a portion of the first winding in each turn of the first winding is disposed in each of the multiple grooves provided in the core, so that the configuration is less likely to be large compared to a case where no grooves are provided. When the outer diameter of the second winding is constant, in the configuration (1) above, the reduction in the cross-sectional area of ​​the core is only an amount equivalent to the cross-sectional area of ​​the grooves, so that it is easy to suppress a reduction in the magnetic path area.

[0019] The above configuration (1) is easy to manufacture because the first winding portion can be made by winding the first winding along the outer circumferential surface of the core portion while aligning it with the groove. That is, when making the first winding portion, the groove can be used as a guide for the first winding.

[0020] (2) In the reactor described in (1) above, The outer peripheral surface of the core portion has a spiral groove provided coaxially with the core portion, Each of the plurality of groove portions constitutes a part of the spiral groove, All turns of the first winding portion may be disposed in the spiral groove.

[0021] The configuration (2) above makes it easy to increase the contact area between the first winding and the core, which makes it easy to transfer heat from the first winding to the core. Therefore, the configuration (2) above makes it easy to improve heat dissipation.

[0022] (3) In the reactor described in (1) or (2), The depth of each of the plurality of grooves may be the same as the length along the depth direction in a cross section of the first winding.

[0023] The configuration (3) above transfers heat from the first winding to the core portion more easily than the configuration (4) described below. This is because the contact area between the first winding and the core portion in the configuration (3) above is likely to be larger than the configuration (4) described below. Furthermore, the configuration (3) also transfers heat from the second winding to the core portion more easily than the configuration (4) described below. This is for the following reason: In the configuration (3) above, the first winding arranged in the groove portion does not protrude from the groove portion. On the other hand, in the configuration (4) described below, a portion of the first winding arranged in the groove portion protrudes from the groove portion. Therefore, the contact area between the second winding and the ridge portion of the core portion in the configuration (3) above is likely to be larger than the configuration (4) described below. The ridge portion is the portion of the outer peripheral surface of the core portion between adjacent groove portions in the axial direction. Therefore, the configuration (3) above transfers heat from the first winding and the second winding to the core portion more easily, resulting in excellent heat dissipation.

[0024] (4) In the reactor described in (1) or (2) above, The depth of each of the plurality of grooves may be smaller than the length of the first winding in the direction of the depth in a cross section thereof.

[0025] The configuration (4) above is easier to manufacture than the configuration (3) above, because in the configuration (4) above, the step between the portion of the first winding protruding from the groove and the ridge can be easily used as a guide when winding the second winding during the manufacturing process.

[0026] (5) In the reactor of (1) or (2), The depth of each of the plurality of grooves may be greater than the length of the first winding in the direction of the depth in a cross section thereof.

[0027] The configuration (5) above, like the configuration (3), is more likely to transfer heat from the first winding and the second winding to the core than the configuration (4), and therefore has excellent heat dissipation properties.

[0028] (6) In any of the reactors described in (1) to (5) above, the first winding and the second winding are rectangular wires, A cross-sectional shape of each of the plurality of grooves taken along the axial direction may be rectangular.

[0029] In the configuration (6), the first winding is easily placed in the groove, and the first winding is easily brought into contact with the groove, so the configuration (6) easily transfers heat from the first winding to the core.

[0030] (7) In the reactor of (6) above, The first winding portion and the second winding portion may be formed by winding the rectangular wire flatwise.

[0031] In the above configuration (7), the flat wire is easier to bend than in the configuration (8) described below, and therefore the first and second winding portions are easier to fabricate.

[0032] (8) In the reactor of (6) above, The first winding portion and the second winding portion may be formed by edgewise winding the rectangular wire.

[0033] When the axial length of the winding portion is constant, the configuration (8) makes it easier to increase the number of turns of the first winding portion and the second winding portion compared to the configuration (7). When the number of turns of the first winding portion and the second winding portion is constant, the configuration (8) makes it easier to shorten the axial length of the first winding portion and the second winding portion compared to the configuration (7). Therefore, the configuration (8) is easier to miniaturize compared to the configuration (7).

[0034] (9) In any of the reactors described in (1) to (8), The core portion has a quadrangular prism shape, The first winding portion and the second winding portion may have a rectangular cylindrical shape.

[0035] The configuration (9) above is easy to manufacture because it is easy to wind the first winding along the outer circumferential surface of the core portion during the manufacturing process. The configuration (9) above makes it easier to increase the contact area between the second winding portion and the installation target of the reactor compared to when the second winding portion is a circular cylinder with the same cross-sectional area. Therefore, the configuration (9) above makes it easier to transfer heat from the second winding portion to the installation target. Furthermore, the configuration (9) above makes it easier to stably install the second winding portion on the installation target.

[0036] (10) In any of the reactors (1) to (9), The core portion is a core body portion mainly made of a magnetic material; an insulating portion provided along an outer circumferential surface of the core body portion, The plurality of grooves may be provided in the insulating portion.

[0037] The above-mentioned configuration (10) is different from the case where the core part is composed of only the core body part without the insulating part, in that the insulating part Main body This makes it easier to improve the insulation between the wire and the coil.

[0038] (11) A magnetic core according to an embodiment of the present disclosure includes: It has a prismatic core, The core portion Outer surface of includes a first plane having a plurality of grooves aligned in the axial direction of the core portion.

[0039] For the reasons explained in the configuration (1) above, the configuration (11) makes it easy to improve heat dissipation and to construct a reactor that can easily increase the number of turns while suppressing an increase in size and a reduction in the magnetic path area.

[0040] (12) In the magnetic core of (11), The outer peripheral surface of the core portion has a spiral groove provided coaxially with the core portion, Each of the plurality of grooves may form a part of the spiral groove.

[0041] The configuration of (12) above makes it easy to construct a reactor with improved heat dissipation performance for the reasons explained in the configuration of (2) above.

[0042] (13) A converter according to an embodiment of the present disclosure includes: The reactor is provided as set forth in any one of (1) to (10) above.

[0043] The converter includes the reactor, and therefore has excellent heat dissipation properties without increasing in size.

[0044] (14) A power conversion device according to an embodiment of the present disclosure includes: The converter (13) is provided.

[0045] The power conversion device includes the converter, and therefore has excellent heat dissipation properties without being large in size.

[0046] Details of the embodiments of the present disclosure

[0023] The details of the embodiments of the present disclosure will be described below with reference to the drawings. The same reference numerals in the drawings indicate the same objects. The sizes of the components shown in the drawings are expressed for the purpose of clarifying the description and do not necessarily represent the actual dimensional relationships.

[0047] First Embodiment [Reactor] A reactor 1 of the first embodiment will be described with reference to FIGS. 1 to 6. The reactor 1 includes a coil 2 and a magnetic core 3. As shown in FIG. 2, the magnetic core 3 has a core portion 30. The core portion 30 is shaped like a rectangular pillar. The coil 2 has a first winding portion 2i and a second winding portion 2e. The first winding portion 2i is disposed on the outer periphery of the core portion 30. The second winding portion 2e is disposed on the outer periphery of the first winding portion 2i. One of the features of the reactor 1 of this embodiment is that it satisfies the following requirements (A) to (C). 2A, the outer peripheral surface of the core portion 30 includes a first plane 35. The first plane 35 has a plurality of grooves 36 aligned in the axial direction of the core portion 30. (B) The first winding portion 2i is made up of a first winding 21. The first winding 21 is wound spirally along the outer peripheral surface of the core portion 30. (C) As shown in FIGS. 3 and 4, a part of the first winding 21 in each turn of the first winding portion 2i is disposed in each of the plurality of grooves 36.

[0048] [Magnetic core] The magnetic core 3 of this embodiment shown in FIG. 2 includes a first middle core portion 31f, a second middle core portion 31s, a first end core portion 33f, and a second end core portion 33s. The core portion 30 of this embodiment constitutes each of the first middle core portion 31f and the second middle core portion 31s. Unlike the fifth embodiment, the core portion 30 of this embodiment, i.e., each of the first middle core portion 31f and the second middle core portion 31s, does not include an insulating portion 30b, which will be described later with reference to FIGS. 10 and 11, and is instead composed of a core body portion 30a mainly made of a magnetic material. The core body portion 30a is composed of a molded body or laminate, which will be described later. The first end core portion 33f and the second end core portion 33s are each composed of a molded body or laminate independent of the first middle core portion 31f and the second middle core portion 31s.

[0049] The first middle core portion 31f, the second middle core portion 31s, the first end core portion 33f, and the second end core portion 33s are combined in an annular shape. A first end face of the first middle core portion 31f and an inner end face of the first end core portion 33f face each other. A second end face of the first middle core portion 31f and an inner end face of the second end core portion 33s face each other. A first end face of the second middle core portion 31s and an inner end face of the first end core portion 33f face each other. two End core part 33 s The inner end faces of the first middle core portion 31f and the first end core portion 33f face each other. A gap material, which will be described later, may be disposed between the first middle core portion 31f and the first end core portion 33f, between the first middle core portion 31f and the second end core portion 33s, between the second middle core portion 31s and the first end core portion 33f, and between the second middle core portion 31s and the second end core portion 33s.

[0050] The first middle core portion 31f and the second middle core portion 31s have the same configuration. The first end core portion 33f and the second end core portion 33s have the same configuration. The following description will be given mainly of the first middle core portion 31f and the first end core portion 33f.

[0051] The first middle core portion 31f has a rectangular prism shape. In this embodiment, the first middle core portion 31f has a quadrangular prism shape. The four corners of the quadrangular prism are rounded. That is, the outer peripheral surface of the first middle core portion 31f, excluding the first end face and the second end face, is composed of four flat surfaces and four corners.

[0052] As shown in FIG. 2 , at least one of the four planes may be the first plane 35 described above. For example, one plane may be the first plane 35, and the remaining three planes may be second planes. Unlike the first plane 35, the second plane is a flat surface on which no groove 36 is provided. In this case, the plane facing the installation target of the reactor 1 may be the first plane 35. For example, two of the four planes may be the first planes 35, and the remaining two planes may be the second planes. In this case, the first planes 35 and the second planes may be arranged alternately in the circumferential direction of the first middle core portion 31f. That is, the first planes 35 may be located opposite each other. For example, all of the four planes may be the first planes 35. In this embodiment, all of the four planes are the first planes 35.

[0053] In this embodiment, the outer peripheral surface of the first middle core portion 31f has one spiral groove 37 arranged coaxially with the first middle core portion 31f. When the outer peripheral surface of the first middle core portion 31f has the spiral groove 37 as in this embodiment, each of the four corners also has multiple grooves 36 arranged in the axial direction. Each of the multiple grooves 36 provided on each first flat surface 35 and each of the multiple grooves 36 provided on each corner constitutes a part of the spiral groove 37. The grooves 36 on adjacent first flat surfaces 35 and corners are continuous. When focusing only on the first flat surfaces 35 or the corners, the grooves 36 are independent of each other, so there are multiple grooves 36. When focusing on the entire outer peripheral surface of the first middle core portion 31f, the spiral groove 37 is continuous, so there is only one spiral groove 37. In this embodiment, the spiral groove 37 is shifted by a quarter pitch every quarter of a turn.

[0054] The cross-sectional shape of each groove 36 cut along the axial direction can be selected appropriately according to the cross-sectional shape of the first winding 21. In this embodiment, the cross-sectional shape is rectangular.

[0055] As shown in FIGS. 3 and 4, the width of each groove 36 is substantially the same as the width of the first winding 21, which is a rectangular wire in this embodiment. The width of the groove 36 is a length along a direction perpendicular to both the extension direction of the groove 36 and the depth direction of the groove 36. Since the width of each groove 36 is substantially the same as the width of the first winding 21, the contact area between the first winding 21 arranged in each groove 36 and the first middle core portion 31f tends to be large. This makes it easier for heat from the first winding 21 to be transferred to the first middle core portion 31f. This results in excellent heat dissipation properties for the reactor 1.

[0056] As shown in Fig. 4, the depth of each groove 36 may be the same as the length along the depth direction in a cross section of the first winding 21 taken along the axial direction, i.e., the thickness of the first winding 21, which is a coated rectangular wire in this embodiment. As shown in Fig. 5, the depth of each groove 36 may be smaller than the thickness of the first winding 21. As shown in Fig. 6, the depth of each groove 36 may be larger than the thickness of the first winding 21.

[0057] The contact area between the first winding 21 and the first middle core portion 31f in the examples shown in FIGS. 4 and 6 is likely to be larger than that in the example shown in FIG. 5. Therefore, the heat of the first winding 21 is more easily transferred to the first middle core portion 31f in the examples shown in FIGS. 4 and 6 than in the example shown in FIG. 5. In the examples shown in FIGS. 4 and 6, the first winding 21 arranged in the groove portion 36 does not protrude from the groove portion 36. On the other hand, in the example shown in FIG. 5, a portion of the first winding 21 arranged in the groove portion 36 protrudes from the groove portion 36. Therefore, the contact area between the second winding 22 and the ridge portion 38 of the first middle core portion 31f in the examples shown in FIGS. 4 and 6 is likely to be larger than that in the example shown in FIG. 5. The ridge portion 38 is a portion of the outer peripheral surface of the first middle core portion 31f between the groove portions 36 of turns of the spiral groove 37 adjacent to each other in the axial direction. Therefore, in the example shown in FIGS. 4 and 6, heat from the second winding 22 is more easily transferred to the first middle core portion 31f than in the example shown in FIG. 5. Furthermore, in the example shown in FIGS. 4 and 6, the outer peripheral surface of the second winding portion 2e is more easily made flush than in the example shown in FIG. 5. Therefore, in the example shown in FIGS. 4 and 6, the outer peripheral surface of the second winding portion 2e is more easily brought into surface contact with the installation object than in the example shown in FIG. 5. An example of an installation object is a cooling base or the inner surface of a case. Therefore, in the example shown in FIGS. 4 and 6, heat from the second winding 22 is more easily transferred to the installation object than in the example shown in FIG. 5. In the example shown in FIG. 5, the step between the portion of the first winding 21 protruding from the groove 36 and the ridge 38 is more easily used as a guide when winding the second winding 22 during the manufacturing process than in the example shown in FIGS. 4 and 6. Therefore, the example shown in FIG. 5 is easier to manufacture than the examples shown in FIGS. 4 and 6.

[0058] The spacing between the groove portions 36 of adjacent turns in the axial direction in the spiral groove 37 can be selected as appropriate. The spacing between the groove portions 36 is the shortest distance between the openings of the groove portions 36. The spacing between the groove portions 36 may be the same as the length of the groove portions 36 along the axial direction, or may be smaller or larger than the length of the groove portions 36 along the axial direction. The smaller the spacing between the groove portions 36, the greater the number of turns in the first winding portion 2i. The larger the spacing between the groove portions 36, the fewer the number of turns in the first winding portion 2i. This makes it easier to ensure a sufficient magnetic path area. Furthermore, the number of turns in the second winding portion 2e that contacts the ridge portions 38 of the first middle core portion 31f tends to be larger. This makes it easier for heat from the second winding 22 to be transferred to the first middle core portion 31f.

[0059] The first end core portion 33f has a columnar shape The first end core portion 33f of this embodiment has a columnar shape with substantially dome-shaped upper and lower surfaces.

[0060] The first middle core portion 31f and the first end core portion 33f are made of a molded body, a powder compact, or a laminate of a composite material.

[0061] A composite material compact is a compact in which soft magnetic powder is dispersed in resin. A composite material compact is obtained by filling a mold with a fluid material in which soft magnetic powder is dispersed in unsolidified resin and then solidifying the resin. A composite material compact with multiple grooves 36 or spiral grooves 37 formed therein can be produced by mold transfer. The content of soft magnetic powder in the resin of a composite material compact can be easily adjusted. Therefore, the magnetic properties of a composite material compact can be easily adjusted. Furthermore, compared to pressed powder compacts, composite material compacts can be easily formed into complex shapes. An example of the content of soft magnetic powder in a composite material compact is 20% by volume or more and 80% by volume or less. An example of the content of resin in a composite material compact is 20% by volume or more and 80% by volume or less. These contents are values ​​when the composite material compact is 100% by volume.

[0062] A powder compact is a compact formed by compressing soft magnetic powder. A powder compact is obtained by filling a cavity with soft magnetic powder and pressing the soft magnetic powder in the cavity with a punch. A powder compact provided with a plurality of grooves 36 can be produced by transfer using at least one of a cavity and a punch. Compared to a composite material compact, a powder compact has a core portion 30 The proportion of soft magnetic powder in the powder compact can be increased. As a result, the magnetic properties of the powder compact can be easily improved. Examples of magnetic properties include relative permeability and saturation magnetic flux density. Furthermore, the powder compact has a higher amount of soft magnetic powder than a composite material compact, and therefore has excellent heat dissipation properties. An example of the content of magnetic powder in the powder compact is 85% by volume or more and 99% by volume or less. This content is the value when the powder compact is 100% by volume.

[0063] The particles constituting the soft magnetic powder are soft magnetic metal particles, coated particles, soft magnetic nonmetal particles, etc. The coated particles may comprise soft magnetic metal particles and an insulating coating provided on the outer periphery of the soft magnetic metal particles. The soft magnetic metal is pure iron or an iron-based alloy, etc. An example of an iron-based alloy is an Fe-Si alloy or an Fe-Ni alloy. An example of an insulating coating is a phosphate. An example of a soft magnetic nonmetal is ferrite.

[0064] Examples of resins used in composite moldings include thermosetting resins and thermoplastic resins. Examples of thermosetting resins include epoxy resins, phenolic resins, silicone resins, and urethane resins. Examples of thermoplastic resins include polyphenylene sulfide resins, polyamide resins, liquid crystal polymers, polyimide resins, and fluororesins. Examples of polyamide resins include nylon 6, nylon 66, and nylon 9T.

[0065] The composite material compact may contain a filler, such as alumina or silica, which contributes to improving heat dissipation and electrical insulation.

[0066] The content of soft magnetic powder in the composite material compact and the content of soft magnetic powder in the powder compact are considered to be equivalent to the area ratio of the soft magnetic powder in the cross section of the compact. The content of soft magnetic powder in the compact is determined as follows: The cross section of the compact is observed with a SEM (scanning electron microscope) to obtain an observation image. The cross section of the compact can be any cross section. The magnification of the SEM is 200x or more and 500x or less. At least 10 observation images are obtained. The total area of ​​all the observation images must be 0.1 cm. 2 That's all. One observation image may be acquired per cross section, or multiple observation images may be acquired per cross section. Each acquired observation image is subjected to image processing to extract the particle contours. Image processing may be, for example, binarization processing. The area proportion of soft magnetic particles in each observation image is calculated, and the average value of these area proportions is determined. This average value is considered to be the content of soft magnetic powder.

[0067] The laminate is formed by stacking multiple magnetic thin plates. The magnetic thin plates have an insulating coating. The magnetic thin plates are, for example, electromagnetic steel plates. A laminate having multiple grooves 36 or spiral grooves 37 can be produced by stacking multiple magnetic thin plates of different areas in the thickness direction of the magnetic thin plates.

[0068] In this embodiment, the first middle core portion 31f, the second middle core portion 31s, the first end core portion 33f, and the second end core portion 33s are formed of a molded body made of a composite material.

[0069] (Gap material) The gap material is made of a material having a lower relative magnetic permeability than the first middle core portion 31f, the second middle core portion 31s, the first end core portion 33f, and the second end core portion 33s. Examples of materials for the gap material include the above-mentioned ceramics and resin.

[0070] [coil] The coil 2 of this embodiment shown in FIG. 2 includes a first coil 2f and a second coil 2s. The first coil 2f and the second coil 2s may or may not be connected to each other. The first coil 2f and the second coil 2s each include a first winding portion 2i and a second winding portion 2e. The first winding portion 2i of the first coil 2f is disposed on the outer periphery of the first middle core portion 31f. The second winding portion 2e of the first coil 2f is disposed on the outer periphery of the first winding portion 2i of the first coil 2f. For convenience of explanation, FIG. 2 shows the second winding portion 2e of the first coil 2f with a two-dot chain line. The first winding portion 2i of the second coil 2s is disposed on the outer periphery of the second middle core portion 31s. The second winding portion 2e of the second coil 2s is disposed on the outer periphery of the first winding portion 2i of the second coil 2s. The first winding portion 2i of the first coil 2f and the second coil 2s increases the number of turns. Therefore, the reactor 1 has excellent inductance. The first winding portion 2i and the second winding portion 2e of the first coil 2f have the same configuration as the first winding portion 2i and the second winding portion 2e of the second coil 2s. The following description will be given representatively of the first winding portion 2i and the second winding portion 2e of the first coil 2f.

[0071] The first winding portion 2i has a rectangular cylindrical shape. The corners of the first winding portion 2i are rounded. The first winding portion 2i is composed of a first winding 21. The first winding 21 is spirally wound along the outer peripheral surface of the first middle core portion 31f. The rectangular cylindrical first winding portion 2i is easy to manufacture because it is easy to wind the first winding 21 along the outer peripheral surface of the first middle core portion 31f during the manufacturing process. The trajectory of each turn of the first winding 21 follows each groove portion 36. The first winding 21 is arranged in the spiral groove 37. This facilitates the transfer of heat from the first winding 21 to the first middle core portion 31f. This results in excellent heat dissipation performance for the reactor 1. The number of turns in the first winding portion 2i is the same as the number of turns in the spiral groove 37. The number of turns in the first winding portion 2i is less than the number of turns in the second winding portion 2e. The number of turns in the first winding portion 2i is small, and therefore the number of turns in the spiral groove 37 is small. This makes it possible to suppress a reduction in the magnetic path area. The pitch of the first winding portion 2i can be selected as appropriate. The pitch is the distance between turns along the width direction of the first winding 21. The pitch is firstIt may be the same as the width of the winding 21, first It may be smaller or larger than the width of the winding 21.

[0072] The second winding portion 2e has a rectangular cylindrical shape. The corners of the second winding portion 2e are rounded. The rectangular cylindrical shape of the second winding portion 2e makes it easier to increase the contact area between the second winding portion 2e and the installation object compared to when the second winding portion 2e is a circular cylindrical shape with the same cross-sectional area. This makes it easier for heat from the second winding portion 2e to be transferred to the installation object. Furthermore, it makes it easier to stably install the second winding portion 2e on the installation object. The second winding portion 2e is composed of a second winding 22. The second winding 22 is wound along the outer peripheral surfaces of the first winding portion 2i and the first middle core portion 31f. The second winding 22 is a continuous winding with the first winding 21. In other words, the second winding 22 is a single winding with no joints with the first winding 21. There are substantially no gaps between the turns of the second winding portion 2e. Adjacent turns of the second winding portion 2e are in contact with each other. Because the number of turns of the second winding portion 2e is greater than the number of turns of the first winding portion 2i, a portion of the second winding portion 2e is brought into contact with the ridge portion 38 of the first middle core portion 31f. Therefore, heat from the second winding portion 2e is also easily transferred to the first middle core portion 31f.

[0073] Known windings can be used for the first winding 21 and the second winding 22. In this embodiment, the first winding 21 and the second winding 22 are coated rectangular wires. Since coated rectangular wires are easily placed in the grooves 36, the first winding 21 and the grooves 3 6 easily come into contact with the first winding 21. Therefore, heat from the first winding 21 is easily transferred to the first middle core portion 31f. The conductor wire of the coated rectangular wire is made of copper rectangular wire. The insulating coating of the coated rectangular wire is made of enamel. The first winding portion 2i and the second winding portion 2e are formed by flatwise winding the coated rectangular wire. The flatwise wound first winding portion 2i and the second winding portion 2e are easier to manufacture than the edgewise wound first winding portion 2i and the second winding portion 2e because the coated rectangular wire is easier to bend.

[0074] The first winding portion 2i is produced by winding the first winding wire 21 along the spiral groove 37 of the first middle core portion 31f. The second winding portion 2e is produced by winding the second winding wire 22 along the outer peripheral surfaces of the first middle core portion 31f and the first winding portion 2i. The first winding wire 21 is wound from a first end to a second end of the first middle core portion 31f. The second winding wire 22 is wound from the second end to the first end. The first winding wire 21 and the second winding wire 22 are connected at the second end.

[0075] Other Embodiments Reactors according to embodiments 2 to 6 that are different from embodiment 1 will be described. The description of embodiments 2 to 6 will focus on the differences from embodiment 1. The description of the same configuration as embodiment 1 may be omitted.

[0076] Second Embodiment As shown in FIG. 7, the reactor of the second embodiment L Alternatively, the first winding portion 2i and the second winding portion 2e may be formed by edgewise winding a coated rectangular wire. When the axial lengths of the first winding portion 2i and the second winding portion 2e are constant, the edgewise wound first winding portion 2i and the second winding portion 2e are more likely to have a larger number of turns than the flatwise wound first winding portion 2i and the second winding portion 2e. When the number of turns of the first winding portion 2i and the second winding portion 2e is constant, the edgewise wound first winding portion 2i and the second winding portion 2e are more likely to have a shorter axial length than the flatwise wound first winding portion 2i and the second winding portion 2e. Therefore, the edgewise wound first winding portion 2i and the second winding portion 2e are more likely to be miniaturized than the flatwise wound first winding portion 2i and the second winding portion 2e. In this embodiment, the width of each groove 36 is the same as the thickness of the first winding wire 21. The depth of each groove 36 is the same as the width of the first winding 21. Note that the depth of each groove 36 may be smaller or larger than the width of the first winding 21.

[0077] Third Embodiment 8, in the reactor of the third embodiment, the contour shape of each groove 36 is U-shaped, and the first winding 21 and the second winding 22 may be round wires. The width and depth of each groove 36 are the same as the diameter of the first winding 21.

[0078] Fourth Embodiment 9, in the reactor of the fourth embodiment, the contour shape of each groove 36 is V-shaped, and the first winding 21 and the second winding 22 may be round wires. The opening width of each groove 36 is larger than the diameter of the first winding 21, and the depth of each groove 36 is larger than the diameter of the first winding 21.

[0079] Fifth Embodiment As shown in FIGS. 10 and 11 , in the reactor of the fifth embodiment, the core portion 30 may include a core body portion 30a and an insulating portion 30b provided along the outer peripheral surface of the core body portion 30a. The insulating portion 30b tends to improve the insulation between the core body portion 30a and the coil 2. The core body portion 30a is made of the above-described molded body or laminate. The insulating portion 30b is made of, for example, the same resin as the resin in the above-described composite material molded body. In this embodiment, the core body portion 30a and the insulating portion 30b are integrated. Unlike this embodiment, the core body portion 30a and the insulating portion 30b may be independent of each other.

[0080] The core body 30a of this embodiment has a quadrangular prism shape, and the outer circumferential surface of the core body 30a is made up of four flat surfaces and four corners.

[0081] As shown in Fig. 10, at least one of the four flat surfaces of the core body 30a may have a plurality of grooves 318 aligned along the axial direction of the core body 30a. Although not shown, the flat surface facing the flat surface on which the plurality of grooves 318 are formed may also have a plurality of grooves 318. Furthermore, the remaining two flat surfaces of the core body 30a may also have a plurality of grooves 318. Furthermore, the four corners of the core body 30a may also have a plurality of grooves 318. The outer peripheral surface of the core body 30a may have one spiral groove 319 arranged coaxially with the core body 30a.

[0082] As shown in FIG. 10 , the insulating portion 30b has a first plane 35 on which the plurality of grooves 36 described above are provided. The first plane 35 of the insulating portion 30b is provided so as to cover one of the four planes of the core body portion 30a on which the plurality of grooves 318 are provided. Each groove 36 is aligned with each groove 318. Although not shown, the insulating portion 30b may be provided so as to cover the four corners of the core body portion 30a. If the corners of the core body portion 30a also have multiple grooves 318, the insulating portion 30b covering the corners of the core body portion 30a also has multiple grooves 36. Each groove 36 at the corners of the insulating portion 30b is aligned with each groove 318 at the corners of the core body portion 30a. The insulating portion 30b may be provided so as to cover the entire outer periphery of the core body portion 30a. The outer periphery of the insulating portion 30b may have one spiral groove 37 described above. The spiral groove 37 is provided coaxially with the insulating portion 30b. The spiral groove 37 of the insulating portion 30b is aligned with the spiral groove 319 of the core body portion 30a.

[0083] Unlike the example shown in Fig. 10, as shown in Fig. 11, none of the four flat surfaces and four corners of the core body 30a need to have multiple grooves 318. That is, the core body 30a need not have a spiral groove 319. The first flat surface 35 of the insulating portion 30b, on which the multiple grooves 36 are provided, is arranged to cover the flat surface of the core body 30a. The outer peripheral surface of the insulating portion 30b may have one spiral groove 37.

[0084] Sixth Embodiment Although not shown in the drawings, in the reactor of the sixth embodiment, the magnetic core may have a middle core portion, a first side core portion, a second side core portion, a first end core portion, and a second end core portion. The middle core portion, the first side core portion, and the second side core portion are arranged side by side so that their axial directions are parallel to each other. The middle core portion is arranged between the first side core portion and the second side core portion. End The core portion is disposed so as to face the first end face of the middle core portion, the first end face of the first side core portion, and the first end face of the second side core portion. End The core portions are arranged to face the second end face of the middle core portion, the second end face of the first side core portion, and the second end face of the second side core portion.

[0085] The magnetic core can be formed, for example, by a combination of E-shaped first core pieces and I-shaped second core pieces, or a combination of U-shaped first core pieces and T-shaped second core pieces. The E-shaped first core pieces are a molded body or laminated body in which a middle core portion, a first side core portion, a second side core portion, and a first end core portion are integrated. The I-shaped second core pieces are formed by a second end core portion. The U-shaped first core pieces are a molded body or laminated body in which a first side core portion, a second side core portion, and a first end core portion are integrated. The T-shaped second core pieces are a molded body or laminated body in which a middle core portion and a second end core portion are integrated.

[0086] In this embodiment, the core part described in the first embodiment 30 The first side core portion and the second side core portion may each be formed by the first coil. 2f is disposed on the outer periphery of the first side core portion, and the second coil 2s The first coil may be disposed on the outer periphery of the second side core portion. 2f and the second coil 2s may be independent of each other.

[0087] Seventh Embodiment [Converter / Power Conversion Device] The reactor 1 according to any one of the first to sixth embodiments can be used in applications that satisfy the following energization conditions. The energization conditions include, for example, a maximum DC current of approximately 100 A to 1000 A, an average voltage of approximately 100 V to 1000 V, and an operating frequency of approximately 5 kHz to 100 kHz. The reactor 1 according to any one of the first to sixth embodiments can be used as a component of a converter mounted on a vehicle 1200, such as an electric vehicle, a hybrid vehicle, or a fuel cell vehicle, or as a component of a power conversion device including this converter.

[0088] As shown in Fig. 12, the vehicle 1200 includes a main battery 1210, a power conversion device 1100 connected to the main battery 1210, and a motor 1220 that is driven by power supplied from the main battery 1210 and used for traveling. The motor 1220 is typically a three-phase AC motor that drives wheels 1250 when traveling and functions as a generator during regeneration. In the case of a hybrid vehicle, the vehicle 1200 includes an engine 1300 in addition to the motor 1220. Although Fig. 12 shows an inlet as a charging point for the vehicle 1200, a plug may also be provided.

[0089] The power conversion device 1100 includes a converter 1110 connected to a main battery 1210, and an inverter 1120 connected to the converter 1110 and performing mutual conversion between direct current and alternating current. The converter 1110 shown in this example boosts the input voltage of the main battery 1210, which is approximately 200 V or more and 300 V or less, to approximately 400 V or more and 700 V or less, when the vehicle 1200 is running, and supplies the voltage to the inverter 1120. During regeneration, the converter 1110 reduces the input voltage output from the motor 1220 via the inverter 1120 to a direct current voltage suitable for the main battery 1210, and charges the main battery 1210. The input voltage is a direct current voltage. When the vehicle 1200 is running, the inverter 1120 converts the DC boosted by the converter 1110 into a predetermined AC and supplies it to the motor 1220, and when regenerating, it converts the AC output from the motor 1220 into DC and outputs it to the converter 1110.

[0090] As shown in FIG. 13 , the converter 1110 includes a plurality of switching elements 1111, a drive circuit 1112 that controls the operation of the switching elements 1111, and a reactor 1115, and converts the input voltage by repeatedly switching the switching elements 1111 on and off. The conversion of the input voltage here refers to boosting and bucking the voltage. The switching elements 1111 are power devices such as field-effect transistors and insulated gate bipolar transistors. The reactor 1115 utilizes the properties of a coil that hinders changes in current flowing through a circuit, and has the function of smoothing changes in current that increase or decrease due to switching operations. The reactor 1115 includes the reactor 1 according to any one of the first to sixth embodiments. The power conversion device 1100 and the converter 1110 that include the reactor 1 are expected to achieve improved heat dissipation without increasing in size.

[0091] In addition to converter 1110, vehicle 1200 includes a power supply converter 1150 connected to main battery 1210, and an auxiliary power supply converter 1160 connected to main battery 1210 and sub-battery 1230, which serves as a power source for auxiliary equipment 1240, and converts the high voltage of main battery 1210 to low voltage. Converter 1110 typically performs DC-DC conversion, while power supply converter 1150 and auxiliary power supply converter 1160 perform AC-DC conversion. Some power supply converters 1150 perform DC-DC conversion. A reactor having a configuration similar to reactor 1 of embodiment 1 or the like, but with a modified size, shape, or the like, can be used as the reactor for power supply converter 1150 and auxiliary power supply converter 1160. Furthermore, reactor 1 of any of embodiments 1 to 6 can be used as a converter that converts input power, and that only boosts or only bucks the voltage.

[0092] The present invention is not limited to these examples, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. [Explanation of symbols]

[0093] 1 reactor 2 coils, 2f first coil, 2s second coil 2i First winding part, 2e Second winding part 21 first winding, 22 second winding 3 magnetic cores, 30 core parts 30a Core Main body , 30b Insulation part 31f First middle core part, 31s Second middle core part 318 groove, 319 spiral groove 33f First end core part, 33s Second end core part 35 first plane, 36 groove, 37 spiral groove, 38 ridge 1100 Power Converter, 1110 Converter 1111 switching element, 1112 drive circuit, 1115 reactor 1120 Inverter 1150 Power supply converter, 1160 Auxiliary power supply converter 1200 vehicles 1210 Main battery, 1220 Motor, 1230 Sub battery 1240 Auxiliary equipment, 1250 Wheels 1300 Engine

Claims

1. a magnetic core having a core portion formed in a prismatic shape; a coil having a first winding portion disposed on an outer periphery of the core portion and a second winding portion disposed on an outer periphery of the first winding portion, the first winding portion is configured by a first winding that is wound in a spiral shape along an outer peripheral surface of the core portion, the second winding portion is configured by a second winding wound along an outer peripheral surface of the first winding portion, the first winding and the second winding are a series of windings, the number of turns of the first winding portion is less than the number of turns of the second winding portion, an outer peripheral surface of the core portion includes a first plane having a plurality of grooves aligned in the axial direction of the core portion; a portion of the first winding in each turn of the first winding portion is disposed in each of the plurality of grooves; Reactor.

2. The outer peripheral surface of the core portion has a spiral groove provided coaxially with the core portion, Each of the plurality of groove portions constitutes a part of the spiral groove, The reactor according to claim 1 , wherein all turns of the first winding in the first winding portion are arranged in the spiral groove.

3. 3. The reactor according to claim 1, wherein a depth of each of the plurality of grooves is the same as a length along the depth direction in a cross section of the first winding.

4. 3. The reactor according to claim 1, wherein a depth of each of the plurality of grooves is smaller than a length of the first winding in a cross section along the depth direction.

5. 3. The reactor according to claim 1, wherein a depth of each of the plurality of grooves is greater than a length of the first winding in a cross section along the depth direction.

6. the first winding and the second winding are rectangular wires, 3. The reactor according to claim 1, wherein each of the plurality of grooves has a rectangular cross-sectional shape taken along the axial direction.

7. The reactor according to claim 6 , wherein the first winding portion and the second winding portion are formed by winding the rectangular wire flatwise.

8. The reactor according to claim 6, wherein the first winding portion and the second winding portion are formed by edgewise winding the rectangular wire.

9. The core portion has a quadrangular prism shape, The reactor according to claim 1 or 2, wherein the first winding portion and the second winding portion are rectangular tubular.

10. The core portion is a core body portion mainly made of a magnetic material; an insulating portion provided along an outer circumferential surface of the core body portion, The reactor according to claim 1 or 2, wherein the plurality of grooves are provided in the insulating portion.

11. A reactor according to claim 1 or 2 is provided. converter.

12. A converter according to claim 11, Power conversion device.

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