Reactor, converter, and power conversion device

Abstract

To provide a reactor capable of preventing a short circuit from occurring between turns of a coil even in the case where a foreign material is present between the turns.SOLUTION: A reactor comprises: an edgewise coil formed of a flat rectangular wire; a magnetic core; and a molded resin part that covers at least a part of the magnetic core. The edgewise coil comprises a plurality of turns configured to form a rectangular shape. Each of the plurality of turns comprises: four linear parts; and four curved corner parts connecting the adjacent linear parts to each other. Each of the four corner parts comprises an outer region in which a gap is provided between the adjacent turns. The mold resin part is present in at least two of the gaps that are diagonally opposite to each other.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a reactor including a coil, a magnetic core, and a resin molded portion. The magnetic core includes an inner core portion and an outer core portion. The resin molded portion covers at least a portion of the surface of the magnetic core and holds the inner core portion and the outer core portion together. The resin molded portion is formed by molding the outer periphery of the assembly of the coil and magnetic core with unhardened resin. Hereinafter, the resin molded portion will be referred to as the molded resin portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-27835 Summary of the Invention [Problem to be solved by the invention]

[0004] When forming the molded resin portion, foreign matter may enter the gaps between the coil turns. For example, when the molded resin portion is formed by injection molding, the foreign matter may be a fragment of the magnetic core that breaks off due to the pressure during injection molding. If foreign matter exists between the coil turns, it may slide between the turns during use of the reactor due to external forces or vibrations caused by coil excitation. If this sliding damages the insulating coating of the coil, it may cause a short circuit between the turns.

[0005] An object of the present disclosure is to provide a reactor that can prevent short circuits between turns of a coil even when a foreign object is present between the turns. Another object of the present disclosure is to provide a converter including the reactor. Another object of the present disclosure is to provide a power conversion device including the converter. [Means for solving the problem]

[0006] The reactor of the present disclosure includes: An edgewise coil made of rectangular wire; A magnetic core; a molded resin portion that covers at least a portion of the magnetic core, the edgewise coil comprises a plurality of turns arranged in a rectangular shape; Each of the plurality of turns includes four straight line portions and four curved corner portions connecting adjacent straight line portions, each of the four corners has an outer region with gaps between adjacent turns; The mold resin portion fills at least two of the gaps located diagonally opposite each other.

[0007] The converter of the present disclosure includes the reactor of the present disclosure.

[0008] The power conversion device of the present disclosure includes the converter of the present disclosure. [Effects of the Invention]

[0009] The reactor of the present disclosure can prevent short circuits between turns of the coil even when a foreign object is present between the turns. The converter and power conversion device of the present disclosure can prevent short circuits between turns of the coil even when a foreign object is present between the turns. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing an outline of a reactor according to an embodiment. [Figure 2]FIG. 2 is a diagram illustrating the relationship between the coil and the molded resin portion in the reactor of FIG. [Figure 3] FIG. 3 is a schematic end view showing one of the plurality of turns that constitute the coil in the reactor of FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view showing a rectangular wire that constitutes a coil in the reactor of FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along line VV of FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a schematic diagram showing the power supply system of a hybrid vehicle. [Figure 8] FIG. 8 is a circuit diagram showing an outline of an example of a power conversion device including a converter. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0012] (1) A reactor according to an embodiment of the present disclosure includes: An edgewise coil made of rectangular wire; A magnetic core; a molded resin portion that covers at least a portion of the magnetic core, the edgewise coil comprises a plurality of turns arranged in a rectangular shape; Each of the plurality of turns includes four straight line portions and four curved corner portions connecting adjacent straight line portions, each of the four corners has an outer region with gaps between adjacent turns; The mold resin portion fills at least two of the gaps located diagonally opposite each other.

[0013] In the reactor of the present disclosure, the molded resin portion fills the gaps in the outer regions of at least the diagonally opposite corners of the turns, thereby suppressing displacement between the coil turns. By suppressing displacement between the coil turns, it is possible to prevent short circuits between the turns, even if a foreign object is present between the coil turns.

[0014] (2) As one form of the above reactor, Each of the four corners has an inner region in which the distance between adjacent turns is narrower than the distance between the gaps.

[0015] In other words, in the above embodiment, the outer regions of the four corners have wider gaps than the inner regions, so the molded resin portion is likely to get into the gaps in the outer regions.

[0016] (3) As one form of the above reactor, The aspect ratio a / b, which is the ratio of the length a of the long side to the length b of the short side in the cross section of the rectangular wire, is 2 or more.

[0017] In the above embodiment, gaps are likely to be formed in the outer regions of the four corners.

[0018] (4) As one form of the above reactor, The bending radius of each of the four corners is 10 mm or less.

[0019] In the above embodiment, gaps are likely to be formed in the outer regions of the four corners.

[0020] (5) As one form of the above reactor, The maximum length between adjacent outer regions is 10 μm or more and 1000 μm or less.

[0021] In the above embodiment, the molded resin portion is likely to get into the gaps between the four outer regions.

[0022] (6) As one form of the reactor, The length of the portion of the molded resin portion that fits into the gap is 25% or more of the length of the long side of the cross section of the rectangular wire.

[0023] In the above embodiment, displacement between the turns of the coil is more easily suppressed.

[0024] (7) A converter according to an embodiment of the present disclosure includes the reactor according to any one of (1) to (6) above.

[0025] The converter of the present disclosure includes the reactor of the present disclosure, and therefore can prevent short circuits between turns of the coil even if a foreign object is present between the turns.

[0026] (8) A power conversion device according to an embodiment of the present disclosure includes the converter described in (7) above.

[0027] The power conversion device of the present disclosure includes the converter of the present disclosure, and therefore can prevent short circuits between turns even if a foreign object is present between turns of the coil.

[0028] [Details of the embodiments of the present disclosure] Specific examples of reactors according to embodiments of the present disclosure will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0029] <Summary> As shown in Fig. 1, the reactor 1 of the embodiment includes a coil 2, a magnetic core 4, and a molded resin portion 5. As shown in Fig. 2, the coil 2 includes a plurality of turns 20. One of the features of the reactor 1 of the embodiment is that, as shown in Fig. 5, gaps 23 are provided at specific locations between adjacent turns 20, and the molded resin portion 5 fits into these gaps 23. Each component will be described in detail below.

[0030] FIG. 1 shows an example of a reactor 1. In FIG. 1, the molded resin part 5 is shown in a simplified rectangular shape. In this reactor 1, a portion of the coil 2 is exposed from the molded resin part 5, and the remainder of the coil 2 and the magnetic core 4 are disposed inside the molded resin part 5. In FIG. 1, the portion disposed inside the molded resin part 5 is indicated by a dashed line. In FIG. 2, the magnetic core 4 of the reactor 1 in FIG. 1 is omitted. In each drawing, for the sake of convenience of explanation, some of the configuration may be shown exaggerated or simplified. The dimensional ratios of each part in the drawings may also differ from the actual ones. The same symbols in the drawings indicate the same objects.

[0031] <Coil> As shown in FIG. 2, the coil 2 is an edgewise coil made of a rectangular wire 3. The coil 2 includes a plurality of turns 20 formed in a rectangular shape. The coil 2 of this example is wound edgewise so that adjacent turns 20 come into contact with each other when the coil 2 is manufactured. The coil 2 wound edgewise so that adjacent turns 20 come into contact with each other is configured so that adjacent turns 20 are close to or in contact with each other on the inside of the coil 2. The coil 2 wound edgewise so that adjacent turns 20 come into contact with each other has a short axial length of the coil 2 made of a plurality of turns 20, making it compact.

[0032] [Rectangular wire] The flat wire 3 is a winding wire having a rectangular cross section. The cross section of the flat wire 3 is a cross section obtained by cutting the flat wire 3 along a plane perpendicular to the longitudinal direction of the flat wire 3. As shown in Fig. 4, the flat wire 3 has a pair of long sides 31 and a pair of short sides 32 in the cross section of the flat wire 3.

[0033] The aspect ratio of the cross section of the rectangular wire 3 is 2 or more. The aspect ratio is the ratio a / b of the length a of the long side 31 to the length b of the short side 32. The aspect ratio is the aspect ratio of the rectangular wire 3 before edgewise winding. The length a of the long side 31 of the rectangular wire 3 before edgewise winding is approximately equal to the length a of the long side 31 of the rectangular wire 3 after edgewise winding. The length b of the short side 32 of the rectangular wire 3 before edgewise winding is approximately equal to the length b of the short side 32 on the inside or outside of the straight portion 21 (FIG. 3) that constitutes the turn 20 of the rectangular wire 3 after edgewise winding. The length of the short side 32 of the corner portion 22 (FIG. 3) that constitutes the turn 20 of the rectangular wire 3 after edgewise winding is larger on the inside and smaller on the outside compared to the length b of the short side 32 of the rectangular wire 3 before edgewise winding. The length of the short side 32 of the corner 22 changes after edgewise winding because, when the rectangular wire 3 is edgewise wound, a compressive force acts on the inside of the bend and a tensile force acts on the outside of the bend at the corner 22. At the corner 22, the compressive force acting on the inside of the bend causes the rectangular wire 3 to expand in the direction of the short side 32, and the tensile force acting on the outside of the bend causes the rectangular wire 3 to become thinner in the direction of the short side 32.

[0034] When the aspect ratio is 2 or more, the edgewise wound flat wire 3 tends to have a smaller length b of the outer short side 32 at the corners 22, as described above. Therefore, gaps 23 (FIG. 5) are likely to be formed in the outer regions 221 of the corners 22, as described below. The aspect ratio should preferably be 4 or more, 5 or more, and particularly 7 or more. In consideration of the edgewise winding of the flat wire 3, the aspect ratio should preferably be 20 or less, and more preferably 15 or less. The aspect ratio should preferably be 2 or more and 20 or less, more preferably 4 or more and 15 or less, 5 or more and 12 or less, and particularly preferably 7 or more and 10 or less.

[0035] The length a of the long side 31 and the length b of the short side 32 can be appropriately selected so as to satisfy the above aspect ratio. The length a of the long side 31 can be, for example, 3 mm to 20 mm, more preferably 5 mm to 15 mm, and particularly preferably 7 mm to 12 mm. The length b of the short side 32 can be, for example, 0.5 mm to 3 mm, more preferably 0.7 mm to 2 mm, and particularly preferably 0.8 mm to 1.5 mm.

[0036] As shown in Fig. 2, the rectangular wire 3 is a coated wire having a conductor wire 38 and an insulating coating 39. The conductor wire 38 may be made of copper or the like. The insulating coating 39 may be made of a resin such as polyamideimide. At both ends of the coil 2, the insulating coating 39 is peeled off to expose the conductor wire 38. Terminals (not shown) are connected to the exposed conductor wire 38.

[0037] 〔turn〕 As shown in FIG. 3, each of the multiple turns 20 has four straight portions 21 and four corners 22. Each turn 20 is rectangular. Each turn 20 is formed by spirally winding the rectangular wire 3 edgewise. Therefore, in FIG. 3, a cutting line is shown at the transition point between adjacent turns 20, dividing the circumferential direction of the turn 20. Each turn 20 is rectangular, with the bend radius R of each corner 22 being 10 mm or less. A bend radius R of 10 mm or less at each corner 22 facilitates the formation of gaps 23 in the outer regions 221 of the corners 22, as described below. The bend radius R of each corner 22 is preferably 8 mm or less, 7 mm or less, 6 mm or less, and particularly preferably 5 mm or less. The bend radius R of the corner 22 is preferably 1 mm or more, and more preferably 2 mm or more, due to the edgewise winding of the rectangular wire 3. The bending radius R of the corner 22 is preferably 1 mm or more and 10 mm or less, more preferably 2 mm or more and 8 mm or less, even more preferably 3 mm or more and 7 mm or less, and particularly preferably 5 mm or more and 6 mm or less.

[0038] [Corner of the turn] The corners 22 of each turn 20 are configured in a curved shape connecting adjacent straight portions 21. As shown in FIG. 5, each corner 22 has an outer region 221, an inner region 222, and a central region 223 in a longitudinal section including the corners 22 of the multiple turns 20. The longitudinal section of the multiple turns 20 is a cross section obtained by cutting the multiple turns 20 with a plane parallel to the axial direction of the turns 20. The outer region 221 is located on the outer side of the turn 20. The inner region 222 is located on the inner side of the turn 20. The central region 223 is located between the outer region 221 and the inner region 222. The outer region 221, the inner region 222, and the central region 223 are regions obtained by dividing the length a of the long side 31 of the rectangular wire 3 shown in FIG. 4 into three equal parts.

[0039] The outer region 221 is configured to taper from the inside to the outside of the turn 20. In other words, the outer region 221 has a thickness that gradually decreases from the inside to the outside of the turn 20. The thickness is the length along the short side 32 (FIG. 4) of the rectangular wire 3. The tip of the outer region 221 is configured to be curved.

[0040] In the outer region 221, a gap 23 is provided between adjacent turns 20. The gap 23 is configured to narrow, for example, from the outside to the inside of the turn 20. In this example, the gap 23 is provided not only in the outer region 221 but also between the central regions 223. A molded resin portion 5, which will be described later, fills the gap 23.

[0041] The maximum length L1 of adjacent outer regions 221 may be 10 μm or more and 1000 μm or less. The maximum length L1 is the length between the inflection points P between the curved tips and the linear side surfaces of adjacent outer regions 221. The maximum length L1 is also the length of the gap 23 along the axial direction of the turns 20. When the maximum length L1 is 10 μm or more, the gap 23 is easily secured, and the molded resin portion 5 (described later) easily enters the gap 23. When the length of the gap 23 is large, the thickness of the outer region 221 becomes relatively small. When the maximum length L1 is 1000 μm or less, the thickness of the outer region 221 is relatively secured. The maximum length L1 may further be 20 μm or more and 900 μm or less, particularly 30 μm or more and 800 μm or less. The maximum length L1 may be 10 μm or more and less than the length b (FIG. 4) of the short side 32 of the rectangular wire 3. The length b of the short side 32 here is the average value of all the turns 20 in the length b of the short side 32 on the inside or outside of the straight portion 21 (FIG. 3).

[0042] The inner region 222 has a thickness equivalent to the length b (FIG. 4) of the short side 32 of the rectangular wire 3 before edgewise winding. The inner region 222 has a thickness greater than that of the outer region 221. The thickness of the inner region 222 is, for example, 1.05 times or more, preferably 1.1 times or more, and particularly 1.2 times or more that of the outer region 221.

[0043] In the inner region 222, the distance between adjacent turns 20 is narrower than the gap 23. In the inner region 222, the distance between adjacent turns 20 may be zero. That is, in the inner region 222, adjacent turns 20 may be in contact with each other. In the inner region 222 of this example, adjacent turns 20 are in contact with each other. When a gap is formed in the inner region 222, the molded resin portion 5 described below may or may not enter the gap. For example, even if a gap is formed in the inner region 222, depending on the viscosity of the resin constituting the molded resin portion 5, the molded resin portion 5 may not be able to enter the gap.

[0044] [Straight section of turn] 6, in the longitudinal cross section including the straight portions 21 of the multiple turns 20, the straight portion 21 of each turn 20 comprises an outer region 211, an inner region 212, and a central region 213. The outer region 211 is located on the outer side of the turn 20. The inner region 212 is located on the inner side of the turn 20. The central region 213 is located between the outer region 221 and the inner region 222. The outer region 211, the inner region 212, and the central region 213 are regions obtained by dividing the length a of the long side 31 of the rectangular wire 3 shown in FIG. 4 into three equal parts.

[0045] In the straight portion 21, the thickness of the outer region 211 is approximately equal to the thickness of the inner region 212. The thickness of the central region 213 is equal to or less than the thickness of the outer region 211 and the thickness of the inner region 212. In this example, the thickness of the central region 213 is equal to the thickness of the outer region 211 and the thickness of the inner region 212.

[0046] In the outer region 211 and the inner region 212, the distance between adjacent turns 20 is narrower than in the outer region 221 at the corners 22. In the outer region 211 and the inner region 212, the distance between adjacent turns 20 may be zero. That is, in the outer region 211 and the inner region 212, adjacent turns 20 may be in contact with each other. In this example, adjacent turns 20 are in contact with each other in the outer region 211 and the inner region 212. When a gap is formed in the outer region 211 and the inner region 212, the molded resin portion 5 described below may or may not enter the gap. For example, even if a gap is formed in the outer region 211 and the inner region 212, the molded resin portion 5 may not enter the gap depending on the viscosity of the resin constituting the molded resin portion 5, etc.

[0047] <Magnetic core> The magnetic core 4 has a portion disposed inside the plurality of turns 20 of the coil 2 and a portion disposed outside the plurality of turns 20. The magnetic core 4 forms a closed magnetic path through which the magnetic flux generated by the coil 2 passes.

[0048] The magnetic core 4 of this example is configured in a θ-shape as a whole. As shown in FIG. 1 , the θ-shaped magnetic core 4 includes one middle core portion 41, two side core portions 42, 43, and two end core portions 44, 45. The middle core portion 41 has a portion disposed inside the plurality of turns 20. Each of the two side core portions 42, 43 is disposed alongside the middle core portion 41 outside the plurality of turns 20. Each of the two end core portions 44, 45 is disposed outside the plurality of turns 20 so as to connect the middle core portion 41 and the two side core portions 42, 43. By connecting the middle core portion 41, the two side core portions 42, 43, and the two end core portions 44, 45, magnetic flux flows in the magnetic core 4 when the coil 2 is excited, forming a closed magnetic circuit. The magnetic flux flows from the middle core portion 41 to the end core portion 44, from the end core portion 44 to each of the two side core portions 42 and 43, from each of the side core portions 42 and 43 to the end core portion 45, and from the end core portion 45 to the middle core portion 41.

[0049] The shape of the middle core portion 41 roughly corresponds to the inner circumferential shape of the plurality of turns 20. A gap exists between the inner circumferential surfaces of the plurality of turns 20 and the outer circumferential surface of the middle core portion 41. For example, a molded resin portion 5 (described later) fills this gap. In this example, the shape of the middle core portion 41 is a rectangular column, and the end face shape of the middle core portion 41 when viewed from the axial direction is rectangular. The corners of the middle core portion 41 are rounded to fit the corners 22 of the plurality of turns 20.

[0050] The shape of the side core portions 42, 43 is not particularly limited as long as it is a shape that extends outside the plurality of turns 20 in the axial direction of the plurality of turns 20. In this example, the side core portions 42, 43 are rectangular parallelepipeds extending in the axial direction of the plurality of turns 20. The side core portions 42, 43 are arranged to face two of the four faces that make up the outer circumferential surface of the plurality of turns 20, which are positioned opposite each other across the axes of the plurality of turns 20. In other words, the side core portions 42, 43 are arranged to sandwich from the outside two of the four faces that make up the outer circumferential surface of the plurality of turns 20, which are positioned opposite each other across the axes of the plurality of turns 20. The faces of the plurality of turns 20 that do not face the side core portions 42, 43 are exposed from the magnetic core 4.

[0051] The shape of the end core portions 44, 45 is not particularly limited as long as it connects the ends of the one middle core portion 41 and the two side core portions 42, 43. In this example, the end core portions 44, 45 are rectangular parallelepipeds that are long in the arrangement direction of the one middle core portion 41 and the two side core portions 42, 43.

[0052] The magnetic core 4 may be formed by combining first core pieces and second core pieces. The shapes of the first core pieces and second core pieces can be selected from various combinations. The magnetic core 4 shown in FIG. 1 is an ET type that combines E-shaped first core pieces with T-shaped second core pieces. The E-shaped first core pieces include a portion of a middle core piece 41, two side core pieces 42 and 43, and an end core piece 44. The T-shaped second core pieces include the remaining portion of the middle core piece 41 and an end core piece 45. Other combinations include, for example, an EU type, an EI type, and a TU type.

[0053] The magnetic core 4 is made of a compact containing a soft magnetic material. Examples of soft magnetic materials include metals such as iron and iron alloys, and non-metals such as ferrite. Examples of iron alloys include Fe-Si alloys and Fe-Ni alloys. Examples of compacts containing soft magnetic materials include powder compacts and compacts of composite materials.

[0054] A powder compact is obtained by compressing and molding a powder made of a soft magnetic material, i.e., soft magnetic powder. Compared to a composite material, a powder compact has a higher ratio of soft magnetic powder in the core pieces. The content of the soft magnetic powder in the powder compact is, for example, more than 80% by volume, or even 85% by volume or more, assuming the powder compact to be 100% by volume.

[0055] In a composite material compact, soft magnetic powder is dispersed in resin. A composite material compact is obtained by filling a raw material in which soft magnetic powder is mixed and dispersed in unsolidified resin into a mold and solidifying the resin. The magnetic properties of the composite material, such as the relative permeability and saturation magnetic flux density, can be easily controlled by adjusting the content of soft magnetic powder in the resin. The content of soft magnetic powder in a composite material compact can be, for example, 30% by volume or more and 80% by volume or less, assuming the composite material to be 100% by volume.

[0056] The soft magnetic powder is an aggregate of soft magnetic particles. The soft magnetic particles may be coated particles having an insulating coating on their surfaces. Examples of the insulating coating include phosphates. Examples of the resin used in the composite material 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 (PPS) resins, polyamide (PA) resins (e.g., nylon 6, nylon 66, nylon 9T, etc.), liquid crystal polymers (LCP), polyimide (PI) resins, and fluororesins. The composite material may contain a filler in addition to the resin. The inclusion of a filler can improve the heat dissipation properties of the composite material. Examples of the filler include powders made of non-magnetic materials such as ceramics and carbon nanotubes. Examples of ceramics include metal or non-metal oxides, nitrides, and carbides. Examples of oxides include alumina, silica, and magnesium oxide. Examples of nitrides include silicon nitride, aluminum nitride, boron nitride, etc. Examples of carbides include silicon carbide, etc.

[0057] At least a portion of the magnetic core 4 is made of a powder compact. When the molded resin portion 5 (described later) is formed by injection molding during the manufacturing process of the reactor 1, the magnetic core 4 made of the powder compact may be partially chipped due to the pressure during injection molding. Therefore, the reactor 1 in which at least a portion of the magnetic core 4 is made of the powder compact is more likely to exhibit the effects of the embodiments (described later).

[0058] <Molded resin part> As shown in FIG. 1 , the molded resin portion 5 covers at least a portion of the magnetic core 4. The molded resin portion 5 has the function of protecting the magnetic core 4 from the external environment. The molded resin portion 5 may also cover the coil 2. If the molded resin portion 5 is interposed between the coil 2 and the magnetic core 4, it is easy to ensure insulation between the coil 2 and the magnetic core 4. If the molded resin portion 5 exists across the coil 2 and the magnetic core 4, it is easy to position the coil 2 and the magnetic core 4 relative to each other. Furthermore, if the molded resin portion 5 exists across the first core piece and the second core piece, it is possible to fix the first core piece and the second core piece to each other.

[0059] In this example, the molded resin part 5 covers the outer periphery of the assembly including the coil 2 and the magnetic core 4. The assembly in this example is protected from the external environment by the molded resin part 5. Furthermore, the assembly in this example is configured such that the coil 2 and the magnetic core 4 are integrated by the molded resin part 5. At least a portion of the outer periphery of the magnetic core 4 or at least a portion of the outer periphery of the coil 2 may be exposed from the molded resin part 5. In this example, a portion of the surface of the multiple turns 20 of the coil 2 that does not face the side core parts 42, 43 is exposed from the molded resin part 5.

[0060] As shown in Figure 5, the molded resin portion 5 fills gaps 23 provided in outer regions 221 of the corners 22 of the multiple turns 20. The molded resin portion 5 that fills gaps 23 contacts the long sides 31 (Figure 4) of each rectangular wire 3. The molded resin portion 5 that fills gaps 23 has the function of suppressing displacement between adjacent turns 20. Displacement between turns 20 refers to displacement between the turns 20 in the axial direction of the multiple turns 20.

[0061] The molded resin portion 5 fills at least two gaps 23 provided in the corners 22 located diagonally of the four corners 22. In other words, the molded resin portion 5 is provided in at least two gaps 23 located diagonally of the four gaps 23. At least two gaps 23 located diagonally of the four gaps 23 are gaps corresponding to the four corners 22 constituting adjacent turns 20. In addition to the two gaps 23 located diagonally, the molded resin portion 5 may also fill at least one of the remaining two gaps 23. The molded resin portion 5 may also fill all four gaps 23.

[0062] The length L2 of the portion of the molded resin portion 5 that penetrates into the gap 23 is 25% or more of the length a (see also FIG. 4) of the long side 31 in the cross section of the rectangular wire 3. The length L2 is the maximum length along the width direction of the rectangular wire 3 that penetrates into the gap 23 of the molded resin portion 5, from the line connecting the tips of the outer regions 221 of adjacent turns 20. The width of the rectangular wire 3 is the length of the rectangular wire 3 in the direction of the long side 31. When the length L2 is 25% or more of the length a, displacement between the turns 20 is more easily suppressed. The longer the length L2, the more easily displacement between the turns 20 is suppressed. The length L2 is preferably 30% or more, 40% or more, and particularly 50% or more of the length a. Because the rectangular wire 3 is wound edgewise, the length L2 is preferably 75% or less, more preferably 70% or less, and particularly preferably 65% ​​or less. The length L2 is 25% to 75% of the length a, more preferably 30% to 75%, even more preferably 40% to 70%, and even more preferably 50% to 65%.

[0063] Examples of the resin constituting the molded resin portion 5 include the same resin as the resin of the composite material described above. The constituent material of the molded resin portion 5 may contain the above-mentioned filler, just like the composite material.

[0064] <Converter / power conversion device> The reactor 1 of the above-described embodiment can be used in applications that satisfy the following energization conditions. Examples of the energization conditions include 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 of the embodiment can be used as a component of a converter mounted on a vehicle such as an electric vehicle or a hybrid vehicle, or as a component of a power conversion device equipped with this converter.

[0065] As shown in Fig. 7, a vehicle 1200 such as a hybrid vehicle or an electric vehicle 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. 7 shows an inlet as a charging point for the vehicle 1200, a plug may also be provided.

[0066] 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 to 300 V, to approximately 400 V to 700 V when the vehicle 1200 is running, and supplies the voltage to the inverter 1120. When regenerating, 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 direct current boosted by the converter 1110 into a predetermined alternating current and supplies the alternating current to the motor 1220, and when regenerating, converts the alternating current output from the motor 1220 into a direct current and outputs the direct current to the converter 1110.

[0067] As shown in FIG. 8, 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. In this case, the conversion of the input voltage means stepping up or down 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 when the current attempts to increase or decrease due to switching operations. The reactor 1115 includes the reactor 1 of the embodiment described above.

[0068] In addition to the converter 1110, the vehicle 1200 also includes a power supply converter 1150 connected to the main battery 1210, and an auxiliary power supply converter 1160 connected to the main battery 1210 and a sub-battery 1230 that serves as a power source for the auxiliary equipment 1240, and converting the high voltage of the main battery 1210 to a low voltage. The converter 1110 typically performs DC-DC conversion, while the power supply converter 1150 and the auxiliary power supply converter 1160 perform AC-DC conversion. Some power supply converters 1150 also perform DC-DC conversion. The reactors of the power supply converter 1150 and the auxiliary power supply converter 1160 may have the same configuration as the reactor 1 of the above-described embodiment, but may be modified in size, shape, and the like as appropriate. The reactor 1 of the above-described embodiment may also be used for a converter that converts input power, such as a converter that only boosts voltage or a converter that only bucks voltage.

[0069] <Effects of the embodiment> In the reactor 1 of the embodiment, the molded resin portion 5 fills the gaps 23 between at least diagonally opposite corners 22 of the four corners 22 that make up the turns 20, thereby suppressing displacement between the turns 20. For example, the reactor 1 of the embodiment can suppress displacement between the turns 20 even when an external force is applied during use of the reactor 1 or when vibrations accompany excitation of the coil 2. By suppressing displacement between the turns 20, even if a foreign object is present between the turns 20, the foreign object does not slide between the turns 20, thereby suppressing damage to the insulating coating 39 of the rectangular wire 3. Therefore, the reactor 1 of the embodiment can prevent a short circuit between the turns 20 even if a foreign object is present between the turns 20.

[0070] The reactor 1 of the embodiment is small because adjacent turns 20 are in contact with each other on the inside and outside of the straight portions 21 of the turns 20 and on the inside of the corners 22. The reactor 1 is small because adjacent turns 20 are in contact with each other, and therefore the axial length of the coil 2 made up of multiple turns 20 is short. Adjacent turns 20 are in contact with each other because, when the coil 2 is manufactured, the turns 20 are wound edgewise so that adjacent turns 20 are in contact with each other.

[0071] In the reactor 1 of the embodiment, the axial length of the coil 2 is short and gaps 23 are easily formed outside the corners 22 of the turns 20 by satisfying the following conditions: The first condition is that the aspect ratio of the cross section of the rectangular wire 3 is 2 or more. The second condition is that the bending radius R of each corner 22 is 10 mm or less. By satisfying these conditions, for example, the maximum length L1 of adjacent outer regions 221 is easily 10 μm or more and 1000 μm or less, and the molded resin portion 5 is easily inserted into the gaps 23. The length L2 of the portion of the molded resin portion 5 that penetrates into the gaps 23 is easily 25% or more of the length a of the long side 31 in the cross section of the rectangular wire 3. The molded resin portion 5 effectively penetrates into the gaps 23, thereby effectively suppressing displacement between the turns 20.

[0072] The power conversion device 1100 of the embodiment and the converter 1110 of the embodiment are equipped with the reactor 1 of the embodiment, and therefore can prevent short circuits between the turns 20 even if a foreign object is present between the turns 20 of the coil 2, making them highly reliable. [Explanation of symbols]

[0073] 1 reactor 2 coil, 20 turn, 21 straight section, 22 corner section 211,221 outer region, 212,222 inner region, 213,223 central region 23 Gap 3 Flat wire, 31 Long side, 32 Short side, 38 Conductor wire, 39 Insulation coating 4 magnetic core 41 Middle core portion, 42, 43 Side core portions, 44, 45 End core portions 5 Molded resin part a, b, L1, L2 length, R bending radius, P inflection point 1100 power conversion device, 1110 converter, 1111 switching element 1112 drive circuit, 1115 reactor, 1120 inverter 1150 Power supply converter, 1160 Auxiliary power supply converter 1200 vehicle, 1210 main battery, 1220 motor 1230 Sub-battery, 1240 Auxiliary equipment, 1250 Wheels, 1300 Engine

Claims

1. An edgewise coil made of rectangular wire; A magnetic core; a molded resin portion that covers at least a portion of the magnetic core, the edgewise coil comprises a plurality of turns arranged in a rectangular shape; Each of the plurality of turns includes four straight line portions and four curved corner portions connecting adjacent straight line portions, each of the four corners has an outer region with gaps between adjacent turns; The maximum length between adjacent outer regions is 10 μm or more and 1000 μm or less, the mold resin portion is inserted into at least two of the gaps located diagonally opposite each other, The length of the portion of the molded resin part that penetrates into the gap is 30% or more and 75% or less of the length of the long side of the cross section of the rectangular wire. Reactor.

2. The reactor according to claim 1 , wherein each of the four corners includes an inner region in which the distance between adjacent turns is narrower than the distance between the gaps.

3. 3. The reactor according to claim 1, wherein an aspect ratio a / b, which is a ratio of a length a of a long side to a length b of a short side in a cross section of the rectangular wire, is 2 or more.

4. The reactor according to claim 1 , wherein each of the four corners has a bending radius of 10 mm or less.

5. A reactor described in any one of claims 1 to 4, wherein at least a portion of the magnetic core is composed of a pressed powder compact.

6. A reactor described in any one of claims 1 to 4, wherein the magnetic core is composed of a molded body of a composite material.

7. A reactor described in any one of claims 1 to 6, wherein the length of the long side is 3 mm or more and 20 mm or less.

8. A reactor described in any one of claims 1 to 7, wherein the length of the short side of the cross section of the flat rectangular wire is 0.5 mm or more and 3 mm or less.

9. A reactor according to any one of claims 1 to 8, converter.

10. A converter according to claim 9, Power conversion device.

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