Reactor, converter, and power conversion device

Abstract

A reactor is provided with: a coil having a winding part; a magnetic core having an inner core portion disposed inside the winding portion; a first spacer disposed between the winding portion and the inner core portion; and a molded member integrating the coil and the magnetic core, the inner core portion having a quadrangular prism shape and comprising a first core portion having a first end surface and a second core portion having a second end surface disposed at a distance from the first end surface, the first spacer having a groove shape, and the second spacer having a groove shape. The groove shape has an inner peripheral surface facing the three outer peripheral surfaces of the inner core portion, and a portion of the molding member is disposed in a first gap between a portion of the inner core portion not facing the inner peripheral surface and the winding portion and a second gap between the first end surface and the second end surface.

Description

TECHNICAL FIELD

[0001] The present application relates to an electric reactor, a converter, and a power conversion device. This application claims priority based on Japanese application "Tokukai 2023-056424" filed on March 30, 2023, and incorporates by reference the entire disclosure of the Japanese application BACKGROUND

[0002] Patent Literature 1 discloses an electric reactor provided with a coil and a magnetic core. The coil has a winding portion. The magnetic core has an intermediate core portion disposed inside the winding portion. The intermediate core portion is composed of a first intermediate magnetic core piece and a second intermediate magnetic core piece. Inside the winding portion, an end surface of the first intermediate magnetic core piece and an end surface of the second intermediate magnetic core piece are disposed apart by a gap.

[0003] The above electric reactor is further provided with a molded resin portion covering at least a part of the magnetic core. The molded resin portion corresponds to the molded member in the present specification. When the molded resin portion is formed, the resin constituting the molded resin portion enters a gap (hereinafter referred to as gap A) between the winding portion and the inner core portion from the end surface position of the winding portion, and reaches a gap (hereinafter referred to as gap B) between the end surface of the first intermediate magnetic core piece and the end surface of the second intermediate magnetic core piece. The molded resin portion that enters the gap B functions as a resin gap portion that adjusts the magnetic properties of the magnetic core. The resin gap portion composed of a part of the molded resin portion can be considered as a part of the inner core portion. PRIOR ART DOCUMENTS PATENT LITERATURE

[0004] Patent Literature 1: Japanese Patent Application Publication No. 2021-141123 SUMMARY

[0005] The electric reactor of the present application is provided with a coil having a winding portion, a magnetic core having an inner core portion and an outer core portion, the inner core portion being disposed inside the winding portion, the outer core portion being disposed outside the winding portion, a first spacer being disposed between the winding portion and the inner core portion, and a molded member that integrates the coil and the magnetic core. The inner core portion has a quadrangular prism shape and is composed of a first core portion having a first end surface disposed inside the winding portion and a second core portion having a second end surface disposed apart from the first end surface by a gap. The first spacer has a groove shape having an inner peripheral surface facing the three outer peripheral surfaces of the inner core portion. A part of the molded member is disposed in a first gap between a part of the inner core portion not facing the inner peripheral surface and the winding portion, and a second gap between the first end surface and the second end surface. BRIEF DESCRIPTION OF DRAWINGS

[0006] Figure 1 is a schematic perspective view of the reactor described in Embodiment 1. Figure 2 is an exploded perspective view of the reactor from which the molding member is removed. Figure 3 is Figure 1 is a III-III sectional view of Figure 4 is a IV-IV sectional view of Figure 3 Figure 5 is a configuration view schematically showing a power supply system of a hybrid vehicle. Figure 6 is a circuit diagram showing an example of a power conversion device provided with a converter. DETAILED DESCRIPTION

[0007] [PROBLEMS TO BE SOLVED BY THE INVENTION] In order to downsize the reactor and improve the heat dissipation of the reactor, there is a demand to reduce the gap A between the winding portion and the intermediate magnetic core piece or to reduce the gap B between the end surface of the first intermediate magnetic core piece and the end surface of the second intermediate magnetic core piece inside the winding portion. In this case, the resin is difficult to fill into the gap A, and in addition, since the gap A and the gap B are orthogonal, the resin is difficult to fill into the gap B through the gap A. If the filling of the resin into the gap B is insufficient and a gap is formed in the gap B, it is possible that the heat dissipation of the reactor is reduced or the function of the resin gap portion is reduced. If, in order to sufficiently fill the resin into the gap B, the pressure of the resin when molding the coil and the magnetic core from the outside is excessively increased, it is possible that the magnetic core is broken by the pressure of the resin.

[0008] One of the objects of the present application is to provide a reactor in which a part of a molding member that integrates a coil and a magnetic core is easily filled into the inside of a winding portion.

[0009] [EFFECTS OF THE INVENTION] The reactor of the present application is a reactor in which a part of a molding member that integrates a coil and a magnetic core is sufficiently filled into the inside of a winding portion.

[0010] [EXPLANATION OF EMBODIMENTS OF THE INVENTION] First, an embodiment of the present application is explained.

[0011] ​The electric reactor according to the embodiment includes a coil having a winding portion, a magnetic core having an inner core portion and an outer core portion, the inner core portion being disposed inside the winding portion, the outer core portion being disposed outside the winding portion, a first spacer being disposed between the winding portion and the inner core portion, and a molding member integrating the coil and the magnetic core. The inner core portion has a quadrangular prism shape, and is composed of a first core portion having a first end surface disposed inside the winding portion and a second core portion having a second end surface disposed apart from the first end surface. The first spacer has a groove shape, and has an inner peripheral surface facing the three outer peripheral surfaces of the inner core portion. A portion of the molding member is disposed between a first gap between a portion of the inner core portion not facing the inner peripheral surface and the winding portion and a second gap between the first end surface and the second end surface.

[0012] In the electric reactor according to the embodiment, the first spacer having the groove shape is disposed in the gap between the inner core portion having the quadrangular prism shape and the winding portion, and the first spacer blocks a portion of the gap. The gap narrowed by the first spacer is the first gap through which the resin constituting the molding member passes when the molding member is formed. In the first gap constituted by the narrowed gap, the filling pressure of the resin is easily maintained high. Therefore, the resin is easily filled into the first gap even without increasing the pressure of the resin when the coil and the magnetic core are molded from the outside. In addition, the high-pressure resin passing through the first gap easily enters the second gap formed between the first end surface of the first core portion and the second end surface of the second core portion constituting the inner core portion. Since the pressure of the resin when the coil and the magnetic core are molded from the outside is not excessively high, the magnetic core is less likely to be damaged by the pressure of the resin. In addition, in the electric reactor according to the embodiment, the resin is sufficiently filled into the first gap and the second gap, and the molding member disposed in the second gap is less likely to have defects such as voids. A portion of the molding member disposed in the second gap having fewer defects functions as a resin gap portion to exhibit desired characteristics.

[0013] The molding member functions as a heat transfer path from the inside of the winding portion toward the outside. In the inside of the winding portion, if the molding member is less likely to have defects such as voids, the function of the molding member as the heat transfer path is less likely to be reduced due to the defects.

[0014] The distance between the winding portion and the inner core portion is reduced by securing the electrically insulating distance between the winding portion and the inner core portion using a portion of the molding member and the first spacer. As a result, the winding portion is downsized. Therefore, the electric reactor according to the embodiment is small-sized.

[0015] <2> In the electric reactor according to <1>, the first spacer can cover 45% or more of the circumference of the inner core portion.

[0016] The circumference of the inner core portion is the length of the outline when the inner core portion is cut in a cross section orthogonal to the axis of the inner core portion. If the first spacer covers 45% or more of the circumference of the inner core portion, the filling pressure of the resin in the first gap is maintained high, and the resin easily spreads sufficiently in the second gap.

[0017] <3> In the reactor according to any one of <1> to <2>, a second spacer can be provided between the end surface of the winding portion and the outer core portion, and the first spacer and the second spacer can be a single piece.

[0018] The second spacer can sufficiently ensure the electrically insulating distance between the end surface of the winding portion and the outer core portion. If the first spacer and the second spacer are a single piece, the position of the first spacer inside the winding portion is easily fixed when the reactor is manufactured. Therefore, the first spacer is less likely to move when the resin constituting the molded member is filled inside the winding portion.

[0019] <4> In the reactor according to any one of <1> to <3>, the thickness of the first spacer can be 0.5 mm or more and 2.0 mm or less.

[0020] If the thickness of the first spacer is 0.5 mm or more, the electrically insulating distance between the winding portion and the inner core portion can be sufficiently ensured. If the thickness of the first spacer is 2.0 mm or less, the heat of the inner core portion is easily released to the winding portion. Therefore, the heat dissipation of the reactor is improved. The thickness of the first spacer being 2.0 mm or less means that the winding portion is small. Therefore, the reactor in which the thickness of the first spacer is 2.0 mm or less is small-sized.

[0021] <5> In the reactor according to any one of <1> to <4>, the width of the first gap can be 0.5 mm or more and 4.0 mm or less.

[0022] The width of the first gap is the distance between the outer peripheral surface of the inner core portion and the inner peripheral surface of the winding portion. If the width of the first gap is 0.5 mm or more, the resin constituting the molded member is easily disposed in the first gap when the molded member is formed. If the width of the first gap is 4.0 mm or less, the heat of the inner core portion is easily released to the winding portion. Therefore, the heat dissipation of the reactor is improved. The width of the first gap being 4.0 mm or less means that the winding portion is small. Therefore, the reactor in which the width of the first gap is 4.0 mm or less is small-sized.

[0023] <6> In the reactor according to any one of <1> to <5>, the width of the second gap can be 0.8 mm or more and 4.0 mm or less.

[0024] If the width of the second gap is 0.8 mm or greater, the resin constituting the molded component is easily disposed in the second gap during molding. If the width of the second gap is 4.0 mm or less, magnetic flux leakage in the second gap is reduced. Consequently, losses caused by leakage magnetic flux can be reduced.

[0025] <7> In the above <1> to <6> In any one of the reactors described above, the magnetic core may be formed by combining a first magnetic core piece and a second magnetic core piece, wherein the first magnetic core piece includes a part of the outer core portion and the first core portion, and the second magnetic core piece includes a part of the outer core portion and the second core portion.

[0026] Since the magnetic core is composed of two core pieces, the work of assembling the magnetic core to the coil is facilitated when manufacturing the reactor, thereby improving the productivity of the reactor.

[0027] <8> The converter of the embodiment includes the above <1> to <7> Any one of the reactors described above.

[0028] The reactor of the embodiment is compact. Therefore, a converter including the reactor of the embodiment is also compact. The reactor of the embodiment has excellent heat dissipation properties. Therefore, a converter including the reactor of the embodiment operates stably.

[0029] <9> The power conversion device according to the embodiment includes the above <8> The converter.

[0030] A power conversion device including the converter according to the embodiment is compact and operates stably.

[0031] [Details of Embodiments of the Invention] Embodiments of the reactor, converter, and power conversion device of the present invention are described below with reference to the accompanying drawings. Like reference numerals in the drawings represent like names. The present invention is not limited to the configurations shown in the embodiments but is defined by the claims, which are intended to encompass all modifications within the meaning and scope of equivalents to the claims.

[0032] <Implementation Method 1> Figure 1 and Figure 2 The reactor 1 of this example shown includes a coil 2, a magnetic core 3, a first spacer 4, and a molded member 5. One of the characteristics of this example lies in the arrangement and shape of the first spacer 4 and the formation of the molded member 5. The reactor 1 of this example will be described in detail below.

[0033] Coil like Figure 2As shown, the coil 2 has at least one winding portion 21. The coil 2 of this example has one winding portion 21. The winding portion 21 is formed by winding the wire in a spiral shape. The wire can be a known wire. The wire of this example is a covered flat wire formed of a conductor wire having an insulating covering. The conductor wire is formed of, for example, a flat wire made of copper. The insulating covering is formed of, for example, enamel. The winding portion 21 of this example is a flat coil obtained by flatly winding the covered flat wire.

[0034] The winding portion 21 has a square tube shape. That is, the end surface of the winding portion 21 of this example has a rectangular frame shape. The corners of the winding portion 21 of this example are rounded. By the winding portion 21 having a square tube shape, the contact area of the winding portion 21 with the installation object is easily made larger than in the case where the winding portion has a circular tube shape of the same cross-sectional area. Therefore, the reactor 1 easily dissipates heat to the installation object via the winding portion 21. In addition, the installation state of the winding portion 21 with respect to the installation object is easily stabilized.

[0035] Here, directions in the reactor 1 are defined with the coil 2 as a reference. First, the direction along the axis of the winding portion 21 from the first end portion of the winding portion 21 toward the second end portion is the XI direction. The direction from the first side surface of the winding portion 21 toward the second side surface is the Yl direction. The direction from the bottom surface of the winding portion 21 toward the upper surface is the Zl direction. The XI direction, the Yl direction, and the Zl direction are orthogonal to each other. The X2 direction, the Y2 direction, and the Z2 direction are the opposite directions of the XI direction, the Yl direction, and the Zl direction, respectively.

[0036] In this example, the end portion 22 of the wire disposed in the XI direction of the winding portion 21 is drawn out from the winding portion 21 in the XI direction. In this example, the end portion 23 disposed in the X2 direction of the winding portion 21 is drawn out in the Y2 direction. In the end portions 22, 23, the insulating covering is peeled off to expose the conductor wire. A terminal member not shown is connected to the exposed conductor wire.

[0037] Unlike this example, in the case where, for example, there are two winding portions 21, the two winding portions 21 can be connected to independent power supplies or can be connected to one power supply.

[0038] Magnetic core The magnetic core 3 is a magnet in which a closed magnetic path is formed inside. The magnetic core 3 is a powder compact or a compact of a composite material. The magnetic core 3 can be formed by combining a magnetic core piece formed of a powder compact and a magnetic core piece formed of a compact of a composite material, or can be formed by covering the outer periphery of a magnetic core piece formed of a powder compact with a composite material.

[0039] The powder compact is obtained by press-molding a raw material powder containing a soft magnetic powder. The soft magnetic powder is, for example, pure iron or an iron alloy. The iron alloy is, for example, a Fe (iron)-Si (silicon) alloy or a Fe-Ni (nickel) alloy. The raw material powder can also contain a lubricant. The content of the soft magnetic powder in the powder compact is, for example, more than 80 vol%, further 85 vol% or more, when the entire powder compact is taken as 100 vol%.

[0040] The molded body of the composite material is obtained by filling a mixture of a soft magnetic powder and an uncured resin into a mold and curing the resin. In the molded body of the composite material, the soft magnetic powder is dispersed in the resin. The resin is, for example, a polyphenylene sulfide (PPS) resin, a polytetrafluoroethylene (PTFE) resin, a liquid crystal polymer (LCP), a polyamide (PA) resin such as nylon 6 or nylon 66, a polybutylene terephthalate (PBT) resin, an acrylonitrile-butadiene-styrene (ABS) resin. The resin can also be a BMC (Bulk molding compound) in which calcium carbonate or glass fibers are mixed in an unsaturated polyester, a kneading type silicone rubber, a kneading type polyurethane rubber. The content of the soft magnetic powder in the composite material is, for example, 30 vol% or more and 80 vol% or less, when the entire composite material is taken as 100 vol%. The content of the soft magnetic powder in the composite material can further be 50 vol% or more, 60 vol% or more, or 70 vol% or more.

[0041] The magnetic core 3 has an inner core portion 31 and an outer core portion 32. The inner core portion 31 is disposed inside the winding portion 21 of the coil 2 along the axis of the winding portion 21. The number of the inner core portion 31 is the same as the number of the winding portion 21. Since the number of the winding portion 21 of the present example is one, the number of the inner core portion 31 of the present example is also one. In the present example, both end portions of the portion of the magnetic core 3 along the axis of the winding portion 21 protrude from the end surface of the winding portion 21. The protruding portion is also a portion of the inner core portion 31.

[0042] The inner core portion 31 has a quadrangular prism shape. The winding portion 21 of the present example has a square tube shape, and thus the inner core portion 31 has a shape along the inner shape of the winding portion 21. The inner core portion 31 is composed of a first core portion 311 and a second core portion 312. As shown in FIG. 1, a gap 8 is formed between the inner core portion 31 and the winding portion 21. A portion of the gap 8 is plugged by the first spacer 4 described later. A first gap 81 of the gap 8 which is not plugged by the first spacer 4 is provided with a portion of the molding member 5 described later. Figure 4

[0043] ​The width W1 of the first gap 81 is, for example, not less than 0.5 mm and not more than 4.0 mm. If the width W1 is not less than 0.5 mm, the resin constituting the molded component 5 can be easily arranged in the first gap 81 when the molded component 5 is formed. If the width W1 is not more than 4.0 mm, the heat of the inner core 31 is easily released to the winding portion 21. Therefore, the heat dissipation of the reactor 1 is improved. If the width W1 is not more than 4.0 mm, the inner dimension of the winding portion 21 can be reduced, and the outer dimension of the winding portion 21 can be reduced accordingly. Therefore, the reactor 1 having a width W1 of not more than 4.0 mm is small. Furthermore, the width W1 can also be not less than 0.8 mm and not more than 3.0 mm.

[0044] like Figure 3 As shown, the first end face 311E of the first core portion 311 is arranged inside the winding portion 21. Similarly, the second end face 312E of the second core portion 312 is also arranged inside the winding portion 21. The first end face 311E and the second end face 312E are separated in a direction along the axis of the inner core portion 31. In other words, a second gap 82 is formed between the first end face 311E and the second end face 312E. A portion of the molded member 5, which will be described later, is arranged in the second gap 82. The molded member 5 arranged in the second gap 82 functions as a gap portion for adjusting the magnetic properties of the magnetic core 3.

[0045] The width W2 of the second gap 82 is, for example, not less than 0.8 mm and not more than 4.0 mm. If the width W2 is not less than 0.8 mm, the resin constituting the molded member 5 easily enters the second gap 82 during formation. If the width W2 is not more than 4.0 mm, magnetic flux leakage in the second gap 82 is reduced. Consequently, losses caused by leakage magnetic flux can be reduced. Furthermore, the width W2 may be not less than 1.0 mm and not more than 3.0 mm.

[0046] The outer core portion 32 is a portion of the magnetic core 3 that is disposed outside the winding portion 21. The shape of the outer core portion 32 is not particularly limited as long as it is a shape that connects the end of the inner core portion 31. Figure 2 As shown, the outer core portion 32 of this example is composed of an end core portion facing the end face of the winding portion 21 in the X1 direction, an end core portion facing the end face of the winding portion 21 in the X2 direction, a side core portion facing the side face of the winding portion 21 in the Y1 direction, and a side core portion facing the side face of the winding portion 21 in the Y2 direction. When viewed from the Z2 direction, the outer core portion 32 is a rectangular ring. Unlike this example, the number of side core portions may also be one. In addition, when the number of winding portions 21 and the number of inner core portions 31 are two, the outer core portion 32 is composed of, for example, an end core portion connecting the ends of the two inner core portions 31, 31 in the X1 direction and an end core portion connecting the ends of the two inner core portions 31, 31 in the X2 direction.

[0047] The magnetic core 3 of this example is composed of a first magnetic core piece 3A and a second magnetic core piece 3B. The first magnetic core piece 3A includes a first core portion 311 of the inner core portion 31 and a portion of the outer core portion 32. The first magnetic core piece 3A is substantially "T"-shaped as viewed from the Z2 direction. The second magnetic core piece 3B includes a second core portion 312 of the inner core portion 31 and a portion of the outer core portion 32. The second magnetic core piece 3B is substantially "E"-shaped as viewed from the Z2 direction. The shapes of the magnetic core pieces 3A, 3B are not particularly limited. For example, both the first magnetic core piece 3A and the second magnetic core piece 3B can be substantially "E"-shaped as viewed from the Z2 direction. In addition to this, the magnetic core 3 can be composed of three or more divided cores. In the case where the number of the winding portions 21 and the number of the inner core portions 31 are both two, the first magnetic core piece 3A and the second magnetic core piece 3B each are, for example, U-shaped.

[0048] The first magnetic core piece 3A of this example is composed of a press powder molded body. The second magnetic core piece 3B of this example is composed of a composite material.

[0049] First Spacers As shown in Figure 3 , the first spacers 4 are disposed between the winding portions 21 and the inner core portions 31. The first spacers 4 of this example have a length that is substantially the same as the entire length of the inner core portions 31 along the axis. Unlike this example, the length of the first spacers 4 of this example can also be shorter than the entire length of the inner core portions 31.

[0050] As shown in Figure 4 , the first spacers 4 have a groove shape that has inner peripheral surfaces 41 that face the three of the four outer peripheral surfaces 31a, 31b, 31c, 31d of the inner core portions 31. The outer peripheral surfaces 31a, 31b, 31c, 31d of the inner core portions 31 are surfaces that face the inner peripheral surfaces of the winding portions 21. The outer peripheral surface 31a is a surface that faces the Z2 direction. The outer peripheral surface 31b is a surface that faces the Y1 direction. The outer peripheral surface 31c is a surface that faces the Y2 direction. The outer peripheral surface 31d is a surface that faces the Z1 direction.

[0051] The inner peripheral surfaces 41 of the first spacers 4 cover the entire surface of the outer peripheral surface 31a, at least a portion of the outer peripheral surface 31b, and at least a portion of the outer peripheral surface 31c. That is, the first spacers 4 having a groove shape press the three outer peripheral surfaces 31a, 31b, 31c of the inner core portions 31 that have a quadrangular prism shape. Therefore, the inner core portions 31 inside the winding portions 21 are disposed at predetermined positions. Therefore, when the resin that constitutes the molded member 5 is filled into the first gaps 81, the positions of the inner core portions 31 are not easily moved.

[0052] As described above, the first spacer 4 has an inner peripheral surface 41 which faces the entire surface of the outer peripheral surface 31a and at least a part of the outer peripheral surfaces 31b, 31c of the inner core portion 31. That is, the first spacer 4 covers more than 25% of the circumference of the inner core portion 31. In other words, the length of the inner peripheral surface 41 of the first spacer 4 in a cross section orthogonal to the axis of the inner core portion 31 is more than 25% of the circumference of the inner core portion 31. On the other hand, the first spacer 4 does not cover the outer peripheral surface 31d of the inner core portion 31. Therefore, the length of the inner peripheral surface 41 of the first spacer 4 in the above cross section is 75% or less of the circumference of the inner core portion 31. The length of the inner peripheral surface 41 of the first spacer 4 in the above cross section may, for example, be 30% or more, 35% or more, 45% or more, or 65% or more of the circumference of the inner core portion 31. In particular, if the length of the inner peripheral surface 41 of the first spacer 4 in the above cross section is 45% or more of the circumference of the inner core portion 31, the molded member 5 easily enters the second gap 82 regardless of the size of the second gap 82.

[0053] In the present example, no gap is substantially formed between the first spacer 4 and the inner core portion 31 and between the first spacer 4 and the winding portion 21. In the present specification, "no gap is substantially formed between two members" means that the gap between the two members is 0.1 mm or less. Unlike the present example, a gap may be formed between the first spacer 4 and the inner core portion 31 and between the first spacer 4 and the winding portion 21. The gap in this case is, for example, 0.5 mm or less.

[0054] The thickness t of the first spacer 4 is, for example, 0.5 mm or more and 2.0 mm or less. If the thickness t is 0.5 mm or more, the electrically insulating distance of the winding portion 21 and the inner core portion 31 can be sufficiently ensured. If the thickness t is 2.0 mm or less, the heat of the inner core portion 31 is easily released to the winding portion 21. Therefore, the heat dissipation of the reactor 1 is improved. If the thickness t is 2.0 mm or less, the inner dimension of the winding portion 21 can be reduced, and the outer dimension of the winding portion 21 can be reduced accordingly. Therefore, the reactor 1 having the thickness t of 2.0 mm or less is compact. The thickness t may, further, be 0.8 mm or more and 2.0 mm or less.

[0055] The first spacer 4 is composed of an insulating material. The material is, for example, PPS resin, PTFE resin, LCP, PA resin, PBT resin, or ABS resin. In addition to these, the material of the first spacer 4 may, for example, be a thermosetting resin such as unsaturated polyester resin, epoxy resin, polyurethane resin, or silicone resin. These resins may contain a ceramic filler. The ceramic filler is, for example, a non-magnetic powder such as alumina or silica.

[0056] The first spacer 4 of this example is integrated with the second spacer 6 described later. In this case, the material of the second spacer 6 is the same as that of the first spacer 4. The structure of the second spacer 6 will be described later.

[0057] Molded member As shown in FIG. 1, the molded member 5 integrates the coil 2 and the magnetic core 3. Figure 1 Figure 2 The molded member 5 covers at least a portion of the outer peripheral surface of the coil 2 and at least a portion of the outer peripheral surface of the magnetic core 3. In this example, a portion of the winding portion 21 of the coil 2 is exposed from the molded member 5. The portion of the winding portion 21 exposed from the molded member 5 contributes to improvement of the heat dissipation of the reactor 1.

[0058] The molded member 5 is composed of, for example, a thermoplastic resin such as PPS resin, PTFE resin, LCP, PA resin, PBT resin, ABS resin, or the like. In addition to this, the molded member 5 can also be composed of a thermosetting resin such as unsaturated polyester resin, epoxy resin, polyurethane resin, silicone resin, or the like. By containing a ceramic filler in these resins, the heat dissipation of the molded member 5 is improved. The ceramic filler is, for example, a non-magnetic powder such as alumina or silica.

[0059] As shown in FIG. 2, a portion of the molded member 5 is disposed in the first gap 81 and the second gap 82. In the case of forming the molded member 5, the combination of the coil 2 and the magnetic core 3 is disposed in a mold, and a resin constituting the molded member 5 is filled into the mold. As shown by the dotted arrows in FIG. 2, the resin is filled from the first gap 81 at the end of the winding portion 21 to the inside of the winding portion 21. Further, as shown by the downward dotted arrows, the resin is filled from the first gap 81 to the second gap 82. Figure 3 Figure 3

[0060] Second spacer As shown in FIG. 3, the reactor 1 of this example further has two second spacers 6, 7. Figure 2 The second spacers 6, 7 are frame-shaped members having through-holes 60, 70. The second spacers 6, 7 are disposed between the end surface of the winding portion 21 and the end core portion of the outer core portion 32. By the second spacers 6, 7, electrical insulation between the winding portion 21 and the outer core portion 32 can be ensured. The second spacers 6, 7 are composed of a material that can be used for the first spacer 4. The through-holes 60, 70 are larger than the cross section of the inner core portion 31 and smaller than the inner periphery of the winding portion 21. The inner core portion 31 penetrates the through-holes 60, 70.

[0061]

[0062] ​​​​The second spacers 6, 7 have slots 61, 71 through which the end portions 22, 23 pass. The slot 61 has a hole extending in the Xl direction. The position of the second spacer 6 relative to the coil 2 is determined by passing the end portion 22 through the slot 61 of the second spacer 6. The slot 71 has a hole extending in the Y2 direction. The position of the second spacer 7 relative to the coil 2 is determined by passing the end portion 23 through the slot 71 of the second spacer 7.

[0063] A pressing portion 62, 72 is provided on the inner peripheral surface of the through hole 60, 70 of the second spacer 6, 7 so as to protrude toward the inside of the through hole 60, 70. As shown in FIG. 6, when the second spacer 6, 7 is disposed between the winding portion 21 and the outer core portion 32, the pressing portion 62, 72 presses the outer peripheral surface 3 Id of the inner core portion 31. That is, the inner core portion 31 is supported from four directions by the inner peripheral surface 41 of the first spacer 4 and the pressing portions 62, 72 of the second spacers 6, 7. Therefore, the position of the inner core portion 31 inside the winding portion 21 is determined. Figure 3

[0064] In this example, the second spacer 6 and the first spacer 4 are integrated. The end portion of the first spacer 4 is inserted into the through hole 70 of the second spacer 7. By this insertion, the first spacer 4, the second spacer 6, and the second spacer 7 are mechanically coupled to determine the positions of each other. In this case, the position of the first spacer 4 inside the winding portion 21 is easily fixed when the reactor 1 is manufactured. Therefore, the first spacer 4 is not easily moved when the resin constituting the molding member 5 is filled into the inside of the winding portion 21.

[0065] Unlike this example, the first spacer 4 can be integrated with the second spacer 6 and the second spacer 7, respectively. For example, a portion of the first spacer 4 of FIG. 5 can be integrated with the second spacer 6, and the remaining portion of the first spacer 4 can be integrated with the second spacer 7. In this case, the end surface of the first spacer 4 integrated with the second spacer 6 and the end surface of the first spacer 4 integrated with the second spacer 7 are butted against each other inside the winding portion 21. Figure 3

[0066] Method for manufacturing a reactor In manufacturing the above-described reactor 1, a combination of the coil 2, the magnetic core 3, the first spacer 4, and the second spacers 6, 7 is manufactured, and the combination is disposed in a mold. Then, a resin that is a material of the molding member 5 is filled into the mold. As shown in FIG. 6, the resin is filled into the inside of the winding portion 21, and the resin is cured. Thus, the reactor 1 is manufactured. Figure 3 ​​The resin enters the inside of the first gap 81 from the end of the winding portion 21 as indicated by the broken arrow. At this time, the pressure of the resin is maintained high in the first gap 81 formed by narrowing the gap 8 with the first spacer 4. Therefore, the resin easily fills into the first gap 81 even without increasing the pressure of the resin filled into the mold. The resin, which is maintained at a high pressure, violently enters the second gap 82 from the first gap 81. Therefore, the resin spreads throughout the second gap 82, and the molded member 5 formed in the second gap 82 by curing the resin is not likely to have defects such as voids. The molded member 5 is connected from the outside of the winding portion 21 to the second gap 82 through the first gap 81. Further, the molded member 5 disposed in the second gap 82 bonds the first core portion 311 and the second core portion 312. Therefore, the reactor 1 is produced so that the coil 2 and the magnetic core 3 are firmly integrated by the molded member 5.

[0067] The molded member 5 disposed in the second gap 82 functions as a heat transfer path to release the heat of the inner core portion 31 to the outside of the inner core portion 31. The molded member 5 disposed throughout the second gap 82 improves the heat dissipation of the reactor 1. In particular, in the reactor 1 of the present example, the molded member 5 disposed in the second gap 82 inside the winding portion 21 is not likely to have defects such as voids. Therefore, the reduction in the heat conductivity from the inside to the outside of the inner core portion 31 and the reduction in the function of the molded member 5 as a resin gap portion due to defects can be suppressed.

[0068] In the present example, the position of the inner core portion 31 inside the winding portion 21 is determined by the first spacer 4 when the molded member 5 is formed. Therefore, the distance between the inner core portion 31 and the winding portion 21, that is, the size of the winding portion 21 can be reduced. Therefore, the reactor 1 of the present example is small and light.

[0069] <Embodiment 2> <Converter · Power Conversion Device> The reactor 1 of the above-described embodiment can be used for applications that satisfy the following energization conditions. As the energization conditions, for example, the maximum direct current is 100 A or more and 1000 A or less, the average voltage is 100 V or more and 1000 V or less, and the use frequency is 5 kHz or more and 100 kHz or less. The reactor 1 of the embodiment can be used, for example, 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 provided with the converter.

[0070] As Figure 5As shown, a vehicle 1200 such as a hybrid vehicle or electric vehicle includes a main battery 1210, a power conversion device 1100 connected to the main battery 1210, and an electric motor 1220 driven by the power supplied from the main battery 1210 for driving. The electric motor 1220 is typically a three-phase AC motor that drives wheels 1250 during driving 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 electric motor 1220. Figure 5 In FIG, the charging portion of the vehicle 1200 is a socket, but a plug may also be provided.

[0071] Power conversion device 1100 includes a converter 1110 connected to a main battery 1210 and an inverter 1120 connected to converter 1110 for converting DC to AC and vice versa. Converter 1110, shown in this example, boosts the input voltage of main battery 1210, which is between 200V and 300V, to between 400V and 700V while vehicle 1200 is running, supplying power to inverter 1120. During regeneration, converter 1110 steps down the input voltage output from motor 1220 via inverter 1120 to a DC voltage suitable for main battery 1210, thereby charging main battery 1210. The input voltage is a DC voltage. Inverter 1120 converts the DC voltage boosted by converter 1110 into a predetermined AC voltage to supply power to motor 1220 while vehicle 1200 is running. During regeneration, inverter 1120 converts the AC output from motor 1220 into DC and outputs it to converter 1110.

[0072] like Figure 6 As shown, converter 1110 includes multiple switching elements 1111, a drive circuit 1112 that controls the operation of switching elements 1111, and a reactor 111. The converter converts the input voltage by repeatedly switching on and off. Input voltage conversion here refers to stepping up or down the voltage. Switching elements 1111 utilize power devices such as field-effect transistors and insulated-gate bipolar transistors. Reactor 1115 utilizes the coil's characteristic of suppressing changes in the current flowing through the circuit, smoothing the current fluctuations as the current increases or decreases due to switching. Reactor 1115 includes reactor 1 according to the embodiment.

[0073] The vehicle 1200 is provided with the converter 1110 in addition to the converter 1150 for the power supply device or the converter 1160 for the auxiliary machine power source, the converter 1150 for the power supply device is connected to the main battery 1210, the converter 1160 for the auxiliary machine power source is connected to the sub-battery 1230 that is a power source of the auxiliary machine group 1240 and the main battery 1210, and converts high voltage of the main battery 1210 into low voltage. The converter 1110 typically performs DC-DC conversion, but the converter 1150 for the power supply device or the converter 1160 for the auxiliary machine power source performs AC-DC conversion. In the converter 1150 for the power supply device, there is also a converter that performs DC-DC conversion. In the reactor of the converter 1150 for the power supply device or the converter 1160 for the auxiliary machine power source, a reactor having the same structure as the reactor 1 of the embodiment and having a size, shape, and the like changed as appropriate can be used. In addition, in the converter that performs conversion of input power and the converter that performs only step-up or the converter that performs only step-down, the reactor 1 of the embodiment or the like can be used.

[0074] <Experimental Example> In the experimental example, the influence of the first spacer 4 on the filling state of the resin into the second gap 82 was investigated by Moldex3D of JSOL Corporation. Moldex3D is a resin flow analysis software.

[0075] The dimensions of the main part of the sample investigated were as follows. The width W1 was the width of the first gap 81. The width W2 was the width of the second gap 82. The height ratio was the ratio at which the first spacer 4 covered the outer peripheral surfaces 31b, 31c of the inner core portion 31 when the length of the inner core portion 31 in the Z1 direction was taken to be 100%. The covering ratio was the ratio at which the first spacer 4 covered the inner core portion 31 when the circumference of the inner core portion 31 was taken to be 100% in a cross section orthogonal to the axis of the inner core portion 31. 2 Sample 1 … width W1 = 2.0 mm, width W2 = 2.0 mm, height ratio = 80%, covering ratio = 65% • Sample 2 … width W1 = 2.0 mm, width W2 = 2.0 mm, height ratio = 40%, covering ratio = 45% • Sample 3 … width W1 = 2.0 mm, width W2 = 2.0 mm, height ratio = 20%, covering ratio = 35% • Sample 4 … width W1 = 2.0 mm, width W2 = 1.5 mm, height ratio = 80%, covering ratio = 65% • Sample 5 … width W1 = 2.0 mm, width W2 = 1.5 mm, height ratio = 40%, covering ratio = 45% • Sample 6 … width W1 = 2.0 mm, width W2 = 1.5 mm, height ratio = 20%, covering ratio = 35%

[0076] In Test Samples 1 to 5, it is known that the resin sufficiently filled the entire second gap 82. On the other hand, in Test Sample 6, it is known that a portion without the resin is formed at the end portion in the Z2 direction of the second gap 82. As a result of investigating the internal-external pressure difference of Test Samples 1 to 5, the internal-external pressure difference in Test Samples 1 to 3 was 0.4 MPa or less, and the internal-external pressure difference in Test Samples 4 and 5 was 2.0 MPa or less. The "internal-external pressure difference" is the pressure difference between the pressure of the resin at the outer periphery of the outer core portion 32 and the pressure of the resin at the center in the Zl direction of the second gap 82. On the other hand, the internal-external pressure difference in Test Sample 6 exceeded 2.0 MPa. From this, it is known that the internal-external pressure difference of 2 MPa or less is an index that the resin is filled in the entire second gap 82.

[0077] From the test results, it is known that if the first spacer 4 has a size of 45% or more of the circumference of the inner core portion 31, the resin is sufficiently filled in the second gap 82 regardless of the thickness of the second gap 82. On the other hand, from the comparison of Test Sample 3 in which the width W2 of the second gap 82 is 2.0 mm and Test Sample 6 in which the width W2 of the second gap 82 is 1.5 mm, it is known that according to the width W2 of the second gap 82, even if the first spacer 4 has a size of 45% or less of the circumference of the inner core portion 31, it is possible that the resin is sufficiently filled in the second gap 82. Explanation of Reference Numerals

[0078] 1 Reactor 2 Coil 21 Winding portion 22, 23 End portion 3 Magnetic core 3A First magnetic core piece 3B Second magnetic core piece 31 Inner core portion 31a, 31b, 31c, 31d Outer peripheral surface 311 First core portion 311E First end surface 312 Second core portion 312E Second end surface 32 Outer core portion 4 First spacer 41 Inner peripheral surface 5 Mold member 6, 7 Second spacer 60, 70 Through hole 61, 71 Slot 62, 72 Pressing portion 8 Gap 81 First gap 82 second gap 1100 power conversion device 1110 converter 1111 switching element 1112 drive circuit 1115 reactor 1120 inverter 1150 converter for power supply device 1160 converter for auxiliary machine power supply 1200 vehicle 1210 main battery 1220 electric motor 1230 auxiliary battery 1240 auxiliary machine 1250 wheel 1300 engine t thickness W1, W2 width

Claims

1. A reactor comprising: a coil having a winding portion; a magnetic core having an inner core portion and an outer core portion, the inner core portion being disposed inside the winding portion, and the outer core portion being disposed outside the winding portion; a first spacer disposed between the winding portion and the inner core portion; and a molding member that integrates the coil and the magnetic core, wherein the inner core portion has a quadrangular prism shape and is composed of a first core portion having a first end surface disposed inside the winding portion and a second core portion having a second end surface disposed apart from the first end surface, the first spacer has a groove shape having an inner peripheral surface facing three outer peripheral surfaces of the inner core portion, and a portion of the molding member is disposed between a first gap between a portion of the inner core portion not facing the inner peripheral surface and the winding portion and a second gap between the first end surface and the second end surface.

2. The reactor according to claim 1, wherein the first spacer covers 45% or more of the circumference of the inner core portion.

3. The reactor according to claim 1 or claim 2, wherein the reactor comprises a second spacer disposed between an end surface of the winding portion and the outer core portion, and the first spacer and the second spacer are a single piece.

4. The reactor according to any one of claims 1 to 3, wherein the first spacer has a thickness of 0.5 mm or more and 2.0 mm or less.

5. The reactor according to any one of claims 1 to 4, wherein the first gap has a width of 0.5 mm or more and 4.0 mm or less.

6. The reactor according to any one of claims 1 to 5, wherein the second gap has a width of 0.8 mm or more and 4.0 mm or less.

7. The reactor according to any one of claims 1 to 6, wherein the magnetic core is composed of a first magnetic core piece and a second magnetic core piece, the first magnetic core piece includes a portion of the outer core portion and the first core portion, and the second magnetic core piece includes a portion of the outer core portion and the second core portion.

8. A converter comprising the reactor according to any one of claims 1 to 7.

9. A power conversion device comprising the converter according to claim 8. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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