Core piece, reactor, converter, power conversion device, and method for manufacturing core piece

Abstract

To provide a core piece which is formed by satisfactorily bonding a first part and a second part having different materials.SOLUTION: A core piece for constituting a magnetic core arranged inside and outside a coil includes a first part composed of a compressed molded body of soft magnetic powder, and a plurality of second parts composed of a molded body of a composite material in which soft magnetic powder is dispersed in a resin, wherein the first part includes a first block part having a part provided so as to face the end face of the coil, and a low step part where each edge portion of two surfaces facing each other out of a plurality of surfaces constituting the first block part is locally lowered, and each of the plurality of second parts has a second block part which has a side face facing any one surface of an inside surface and an outside surface of the coil, and is arranged so as to face the side face of the adjacent second part, and a projection part which is provided on an edge of the end face constituting the second block part so as to be overlapped with the low step part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a core piece, a reactor, a converter, a power conversion device, and a method for manufacturing the core piece. [Background technology]

[0002] Patent Document 1 discloses a core piece formed by combining a first core piece and a second core piece. The first core piece is formed of a composite material molded body in which soft magnetic powder is dispersed in resin. The second core piece is formed of a powder compact of soft magnetic powder. The core piece is manufactured by placing the second core piece in a mold and molding the first core piece around the second core piece. Hereinafter, the part of the core piece formed of the powder compact is called the first part, and the part of the core piece formed of the composite material molded body is called the second part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-45166 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a core piece formed by combining a first portion and a second portion made of different materials, it is desirable that the first portion and the second portion are well bonded to each other. For example, even when a plurality of second portions formed independently of each other are bonded to the first portion, it is desirable that the first portion and each second portion are well bonded to each other.

[0005] An object of the present disclosure is to provide a core piece in which a first portion and a second portion made of different materials are well joined. Another object of the present disclosure is to provide a reactor including the core piece. 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. Another object of the present disclosure is to provide a method for manufacturing a core piece in which a first portion and a second portion made of different materials are well joined. [Means for solving the problem]

[0006] The core pieces of the present disclosure are core pieces for forming a magnetic core to be arranged inside and outside a coil, and include a first portion formed of a compact of a soft magnetic powder and a plurality of second portions formed of a compact of a composite material in which soft magnetic powder is dispersed in a resin. The first portion includes a first block portion having a portion provided to face an end face of the coil, and a low step portion in which the edges of two of the plurality of faces that face each other are locally lowered. Each of the plurality of second portions includes a second block portion having a side surface that faces either the inner surface or the outer surface of the coil and arranged to face the side surface of the adjacent second portion, and a protrusion provided on the edge of the end face that constitutes the second block portion so as to overlap the low step portion. Effect of the Invention

[0007] The core piece of the present disclosure is formed by satisfactorily joining a first section and a second section made of different materials. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view showing a core piece according to a first embodiment. [Diagram 2] FIG. 2 is a schematic exploded perspective view of the core piece of the first embodiment. [Diagram 3] FIG. 3 is a schematic perspective view showing a first portion of the core piece of the first embodiment. [Figure 4] FIG. 4 is a schematic diagram illustrating a method for producing the core piece according to the first embodiment. [Diagram 5] FIG. 5 is a schematic perspective view showing the reactor of the first embodiment. [Figure 6] FIG. 6 is a schematic diagram showing a flow of magnetic flux in a magnetic core of the reactor of the first embodiment. [Figure 7] FIG. 7 is a schematic perspective view showing a core piece according to the second embodiment. [Figure 8] FIG. 8 is a schematic exploded perspective view of a core piece according to the second embodiment. [Figure 9] FIG. 9 is a schematic perspective view showing the reactor of the second embodiment. [Figure 10] FIG. 10 is a schematic diagram showing a power supply system of a hybrid vehicle. [Figure 11] FIG. 11 is a circuit diagram showing an example of a power conversion device including a converter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be listed and described.

[0010] (1) A core piece according to an embodiment of the present disclosure is a core piece for forming a magnetic core arranged inside and outside a coil, and includes a first portion formed of a compact of a soft magnetic powder and a plurality of second portions formed of a compact of a composite material in which soft magnetic powder is dispersed in a resin. The first portion includes a first block portion having a portion provided so as to face an end face of the coil, and a low step portion in which edges of two of the plurality of faces constituting the first block portion that face each other are locally lowered. Each of the plurality of second portions includes a second block portion having a side surface facing either the inner surface or the outer surface of the coil and arranged so as to face the side surface of the adjacent second portion, and a protrusion provided on an edge of the end face constituting the second block portion so as to overlap the low step portion.

[0011] The powder compact can have a higher content of soft magnetic powder in the compact than the composite material compact. The powder compact with a high content of soft magnetic powder has high magnetic permeability, but is prone to magnetic saturation. In particular, in a high current operating environment, the powder compact is prone to magnetic saturation and increased iron loss. The composite material compact has a lower magnetic permeability than the powder compact, but is less prone to magnetic saturation in a high current operating environment and has low iron loss. Therefore, a core piece in which a first portion made of the powder compact and a second portion made of the composite material compact are combined has excellent magnetic properties even in a high current.

[0012] The first portion made of a powder compact and the second portion made of a composite material compact are mainly joined at their opposing end faces. The first portion and the second portion are also joined at the lower step provided in the first portion and the protrusion provided in the second portion, in addition to the joint between the end faces described above. The lower step is provided on two surfaces of the first block portion of the first portion, and the protrusion is provided so as to overlap each of the lower step. In this configuration, the protrusion sandwiches the first portion at the lower step. The core piece is manufactured by filling a composite material into a mold in which a partial core piece is arranged, as described below. The partial core piece becomes the first portion. The composite material filled in the mold solidifies while shrinking. The composite material solidified so as to overlap the lower step of the first portion becomes the protrusion. By providing the protrusion so as to overlap the lower step, the first portion and the second portion of the core piece are well joined even if they are made of different materials.

[0013] (2) In the core piece described in (1) above, the multiple second portions may be configured independently of each other, and the first portion may have the low step portion corresponding to the protrusions of each of the multiple second portions.

[0014] Even if the multiple second parts are constructed independently of one another, the first part has a low step portion corresponding to the protrusion of each second part, so that the first part and the second part are joined well.

[0015] (3) In the core piece described in (1) or (2) above, an outer surface of the first portion at the joint between the low step portion and the protrusion may be flush with an outer surface of each of the plurality of second portions.

[0016] If the outer surface of the first portion at the joint is flush with the outer surfaces of the second portions, the joint is less likely to interfere with a member facing the core piece, such as a coil.

[0017] (4) In the core piece according to any one of (1) to (3) above, the second regions may include molded bodies made of composite materials different from one another.

[0018] The multiple second portions include, for example, a portion arranged to face the inner surface of the coil and a portion arranged to face the outer surface of the coil. The portion arranged to face the inner surface of the coil is a portion arranged inside the coil. The portion arranged to face the outer surface of the coil is a portion arranged outside the coil. If the portion arranged inside the coil and the portion arranged outside the coil are made of moldings of different composite materials, it is easy to adjust the magnetic properties of the entire core piece.

[0019] (5) In the core piece described in (1) above, the protrusion may include a connecting protrusion connected to all of the plurality of second portions, and the connecting protrusion may be arranged on one of two mutually facing faces among the plurality of faces constituting the first block portion so as to continuously overlap both the low step portion and a portion other than the low step portion.

[0020] When the connecting protrusion is provided on one of the two surfaces so as to overlap not only the low step portion but also a portion other than the low step portion, a large contact area between the first portion and the second portion can be ensured, and the first portion and the second portion can be more easily joined. When the connecting protrusion is provided so as to overlap a portion other than the low step portion, a portion of the second portion is arranged to face the end face of the coil. By arranging a portion of the second portion to face the end face of the coil, the magnetic properties are superior even with a large current.

[0021] (6) A reactor according to an embodiment of the present disclosure comprises a magnetic core formed by combining first core pieces and second core pieces, and a coil arranged in a part of the magnetic core, wherein at least one of the first core pieces and the second core pieces is a core piece described in any one of (1) to (5) above.

[0022] A reactor equipped with a magnetic core including the above-mentioned core pieces has excellent magnetic characteristics.

[0023] (7) A converter according to an embodiment of the present disclosure includes the reactor described in (6) above.

[0024] A converter including the above reactor has excellent magnetic characteristics.

[0025] (8) A power conversion device according to an embodiment of the present disclosure includes the converter described in (7) above.

[0026] A power conversion device including the above converter has excellent magnetic characteristics.

[0027] (9) A method for manufacturing a core piece according to an embodiment of the present disclosure includes the steps of preparing a die having a first space and a plurality of second spaces that communicate with each other, arranging a partial core piece made of a compressed compact of soft magnetic powder in a space including the first space, and filling each of the plurality of second spaces with a composite material in which soft magnetic powder is dispersed in a resin. Each of the plurality of second spaces extends in a direction intersecting with the first space and is arranged side by side with each other. The partial core piece includes a first block portion and a lower step portion in which the edges of two mutually facing surfaces among the plurality of surfaces that constitute the first block portion are locally lowered. In the filling step, the composite material is filled into each of the plurality of second spaces so as to overlap the lower step portion.

[0028] In the above-mentioned core piece manufacturing method, the partial core pieces are placed in a space including the first space of the mold, and the composite material is filled in the second space, so that the composite material covers the end faces of the partial core pieces and covers the low step portions. The composite material filled in the mold solidifies while shrinking. The partial core pieces become the first portion, and the composite material filled in the second space solidifies to become the second portion. The solidified composite material overlapping the low step portions becomes protrusions. The low step portions are provided on two surfaces of the first block portion of the partial core pieces, and the protrusions are formed to overlap each low step portion. In this configuration, the protrusions sandwich the partial core pieces at the low step portions. In the above-mentioned core piece manufacturing method, the composite material solidifies so as to sandwich the two surfaces of the partial core pieces in addition to the end faces, so that a core piece in which two portions of different materials are well joined to each other can be manufactured.

[0029] (10) In the method for manufacturing a core piece described in (9) above, in the filling step, at least two of the second spaces may be filled with the composite materials different from each other.

[0030] The composite material filled in each of the multiple second spaces, for example, constitutes a portion arranged to face the inner surface of the coil and a portion arranged to face the outer surface of the coil. The portion arranged to face the inner surface of the coil is a portion arranged inside the coil. The portion arranged to face the outer surface of the coil is a portion arranged outside the coil. If the portion arranged inside the coil and the portion arranged outside the coil are made of moldings of different composite materials, it is easy to adjust the magnetic properties of the entire core piece.

[0031] [Details of the embodiment of the present disclosure] Specific examples 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. In each drawing, for convenience of explanation, some of the configurations may be exaggerated or simplified. The dimensional ratios of each part in the drawings may also differ from the actual ratios. Note that the present invention is not limited to these examples, but is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0032] <Embodiment 1> <Core Piece> A core piece 1 of the first embodiment will be described with reference to Figs. 1 to 3. The core piece 1 is a component of a reactor 7 described later. As shown in Fig. 1, the core piece 1 is an integral body in which a first portion 11 and a plurality of second portions 12 are integrally molded. One of the features of the core piece 1 of the first embodiment is that the first portion 11 and the plurality of second portions 12 made of different materials are well joined. In the core piece 1 of the first embodiment, the plurality of second portions 12 are formed independently of each other, and each second portion 12 is joined to the first portion 11. In the following, the overall shape of the core piece 1 will be described first, and then the configurations of the first portion 11 and each second portion 12 will be described.

[0033] [Overall shape of core piece] The core piece 1 includes one middle core portion 21, two side core portions 3 and 4, and one end core portion 5. The core piece 1 has an E-shape configured with the middle core portion 21, the two side core portions 3 and 4, and the end core portion 5. In Fig. 1, the boundary between the middle core portion 21 and the end core portion 5 is indicated by a two-dot chain line.

[0034] In the following, the first direction D1, the second direction D2, and the third direction D3 may be used for explanation. The first direction D1 is a direction in the middle core portion 21 that is along the axis of the middle core portion 21 and moves away from the joint surface with the end core portion 5. The second direction D2 is a direction from the side core portion 3 toward the side core portion 4 along the arrangement of the middle core portion 2 and the two side core portions 3 and 4. The third direction D3 is a direction from the lower surface toward the upper surface of the core piece 1. The lower surface of the core piece 1 includes a second surface 112 of a first block portion 110 that constitutes a first portion 11 described later with reference to FIG. 2 and FIG. 3. The upper surface of the core piece 1 includes a first surface 111 of the first block portion 110. The first direction D1, the second direction D2, and the third direction D3 are perpendicular to each other. In each figure, the first direction D1, the second direction D2, and the third direction D3 are each indicated by a single arrow. Hereinafter, the opposite directions of the first direction D1, the second direction D2, and the third direction D3 may also be referred to as the first direction D1, the second direction D2, and the third direction D3, respectively.

[0035] The middle core portion 21 has a portion that is disposed inside the winding portion 90 (FIGS. 5 and 6) of the coil 9 described later. The middle core portion 21 is a portion that extends in a direction intersecting with the end core portions 5, and may have a portion that is disposed outside the winding portion 90. In other words, the middle core portion 21 may have a portion that is disposed inside the winding portion 90 and a portion that is disposed outside the winding portion 90. The shape of the middle core portion 21 roughly corresponds to the inner peripheral shape of the winding portion 90. The middle core portion 21 in this example is a rectangular block body. The corners of the middle core portion 21 are rounded to fit the corners of the winding portion 90.

[0036] The two side core parts 3, 4 are arranged side by side with the middle core part 21 outside the winding part 90 (FIGS. 5 and 6) of the coil 9 described later. The two side core parts 3, 4 are arranged to sandwich the middle core part 21 with a gap between them. The shape of each side core part 3, 4 may be a shape that allows the side core part 3, 4 to be arranged side by side with the middle core part 21. Each side core part 3, 4 in this example is a rectangular block body. In this example, the two side core parts 3, 4 have the same shape and dimensions. The length of each side core part 3, 4 in this example along the first direction D1 is longer than the length of the middle core part 21 in the first direction D1. The length of each side core part 3, 4 in the first direction D1 may be equal to or shorter than the length of the middle core part 21 in the first direction D1. The length of each side core part 3, 4 in this example along the second direction D2 is shorter than the length of the middle core part 21 in the second direction D2. The total length of each of the side core portions 3, 4 in the second direction D2 in this example is shorter than the length of the middle core portion 21 in the second direction D2. The total length of each of the side core portions 3, 4 in the second direction D2 may be equal to or greater than the length of the middle core portion 21 in the second direction D2. The length of each of the side core portions 3, 4 in this example in the third direction D3 is the same as the length of the middle core portion 21 in the third direction D3. The length of each of the side core portions 3, 4 in the third direction D3 may be shorter or longer than the length of the middle core portion 21 in the third direction D3. The shapes and dimensions of the two side core portions 3, 4 may be different.

[0037] The end core portion 5 is disposed so as to connect the middle core portion 21 and the two side core portions 3, 4 outside the winding portion 90 (FIGS. 5 and 6) of the coil 9 described later. The shape of the end core portion 5 may be any shape that connects the middle core portion 21 and the two side core portions 3, 4. The end core portion 5 in this example is a rectangular block body. The length of the end core portion 5 along the third direction D3 is the same as the length of the middle core portion 21 along the third direction D3. The length of the end core portion 5 along the third direction D3 may be shorter or longer than the length of the middle core portion 21 along the third direction D3.

[0038] [First part] The first portion 11 is made of a compact made of soft magnetic powder. The first portion 11 includes a first block portion 110 and lower step portions 115 and 116, as shown in FIGS.

[0039] <Material> The powder compact constituting the first portion 11 is obtained by pressing raw material powder containing soft magnetic powder. The powder compact can have a higher content of soft magnetic powder in the compact than a compact of a composite material described later. A powder compact with a high content of soft magnetic powder has high magnetic permeability. The content of soft magnetic powder in the powder compact is, for example, more than 80 volume %, or even 85 volume % or more, when the powder compact is taken as 100 volume %. The raw material powder may contain a lubricant.

[0040] The soft magnetic powder is, for example, composed of soft magnetic metal particles, coated particles, or soft magnetic nonmetal particles. The coated particles include soft magnetic metal particles and an insulating coating provided on the outer periphery of the soft magnetic metal particles. The soft magnetic metal is, for example, pure iron or an iron-based alloy. The iron-based alloy is, for example, an Fe-Si alloy or an Fe-Ni alloy. The insulating coating is, for example, a phosphate. The soft magnetic nonmetal is, for example, a ferrite.

[0041] <First Block> The first block portion 110 is a block body having a portion provided so as to face an end surface 91 (FIG. 6) of a wound portion 90 of the coil 9 described below. The first block portion 110 of this example includes a portion of the middle core portion 21 and the end core portion 5. The first block portion 110 of this example has a T-shape constituted by the portion of the middle core portion 21 and the end core portion 5.

[0042] 2 and 3, the multiple surfaces constituting the first block portion 110 include a first surface 111, a second surface 112, and an end surface 113. The first surface 111 and the second surface 112 are surfaces facing each other in the third direction D3. The end surface 113 faces the end surfaces 123A, 123B, and 123C of each second portion 12 shown in FIG. 2. The end surface 113 is a surface joined to the end surfaces 123A, 123B, and 123C.

[0043] <Low section> The first surface 111 has a low step 115. The low step 115 is provided on the edge of the first surface 111. The low step 115 is a portion where the edge of the first surface 111 is locally lowered. In other words, the low step 115 is a portion that is lower than the rest of the first surface 111. The first portion 11 having the low step 115 has a density near the edge of the first surface 111 that is equivalent to the density of other portions. The first portion 11 having the low step 115 has fewer cracks on the edge of the first surface 111.

[0044] The low step 115 may be provided continuously around the entire circumference of the first surface 111. The low step 115 in this example is provided on the edge of the first surface 111 from the end core portion 5 to the middle core portion 21. When the low step 115 is provided continuously around the entire circumference of the first surface 111, the joining between the low step 115 and the protrusion 125 is ensured well regardless of the number of the second portions 12, that is, the number of the protrusions 125. When the low step 115 is provided continuously around the entire circumference of the first surface 111, a part of the low step 115 is covered by the protrusion 125. When the low step 115 is provided continuously around the entire circumference of the first surface 111 and the reactor 7 described later includes a molded resin portion 10, at least a part of the remaining part of the low step 115 may be covered by the molded resin portion 10.

[0045] The first surface 111 is flat except for its edges. The surface extending from this flat surface to the lower step 115 is an inclined surface. The bottom surface of the lower step 115 is flat. In this example, the lower step 115 has a frame-shaped flat surface that surrounds the outside of the inclined surface. The width of the flat surface that constitutes the bottom surface of the lower step 115 is very narrow. In the first surface 111 of this example, the end core portion 5 and the middle core portion 21 are flush with each other.

[0046] The step in low step 115 relative to a portion other than the edge of first surface 111 is, for example, 1 mm or more and 10 mm or less. The step is the depth of low step 115. If the step in low step 115 is 1 mm or more, a good bond with protrusion 125 of second portion 12, which will be described later, is likely to be ensured. If the step in low step 115 is 10 mm or less, end surface 113 is likely to be relatively well ensured. The step in low step 115 may be 1 mm or more and 7 mm or less, 1 mm or more and 4 mm or less, or 1 mm or more and 3 mm or less.

[0047] As shown in FIG. 3, the second surface 112 has a low step 116. The low step 116 is provided on the edge of the second surface 112. The low step 116 is a portion where the edge of the second surface 112 is locally lowered. In other words, the low step 116 is a portion that is lower than the other portions of the second surface 112 and forms a step. In the first portion 11 having the low step 116, the density near the edge of the second surface 112 is equivalent to the density of other portions. In the first portion 11 having the low step 116, there are fewer cracks on the edge of the second surface 112.

[0048] The low step 116 may be provided continuously around the entire circumference of the second surface 112. The low step 116 in this example is provided on the edge of the second surface 112 from the end core portion 5 to the middle core portion 21 shown in FIG. 1. When the low step 116 is provided continuously around the entire circumference of the second surface 112, the low step 116 and the protrusion 126 are well bonded to each other regardless of the number of second portions 12 shown in FIG. 2, that is, the number of protrusions 126. When the low step 116 is provided continuously around the entire circumference of the second surface 112, a part of the low step 116 is covered by the protrusion 126. When the low step 116 is provided continuously around the entire circumference of the second surface 112 and the reactor 7 described later includes a molded resin portion 10, at least a part of the remaining part of the low step 116 may be covered by the molded resin portion 10 shown in FIG. 5.

[0049] The second surface 112 is flat except for its edge. The surface extending from this flat surface to the lower step 116 is an inclined surface. The bottom surface of the lower step 116 is flat. In this example, the lower step 116 has a frame-shaped flat surface that surrounds the outside of the inclined surface. The width of the flat surface that constitutes the bottom surface of the lower step 116 is very narrow. In the second surface 112 in this example, the end core portion 5 and the middle core portion 21 are flush with each other.

[0050] The step in low step 116 relative to a portion other than the edge of second surface 112 is, for example, 1 mm or more and 10 mm or less. The step is the depth of low step 116. If the step in low step 116 is 1 mm or more, a good bond with protrusion 126 of second portion 12, which will be described later, is likely to be ensured. If the step in low step 116 is 10 mm or less, end surface 113 is likely to be relatively well ensured. The step in low step 116 may be 1 mm or more and 7 mm or less, 1 mm or more and 4 mm or less, or 1 mm or more and 3 mm or less.

[0051] [Second part] Each of the second parts 12 is made of a molded body of a composite material in which soft magnetic powder is dispersed in resin. As shown in FIG. 2, the core piece 1 of this example has three second parts 12A, 12B, and 12C. The second part 12A has a second block part 120A and protrusions 125 and 126. The second part 12B has a second block part 120B and protrusions 125 and 126. The second part 12C has a second block part 120C and protrusions 125 and 126. The second parts 12A, 12B, and 12C are made of the same material. In the following, the second parts 12A, 12B, and 12C having the same configuration will be referred to as the second parts 12 without distinction.

[0052] <Material> The composite material compact constituting the second portion 12 is manufactured by filling a mold with raw material in which soft magnetic powder is mixed and dispersed in unsolidified resin, and solidifying the resin. The magnetic properties of the composite material, such as magnetic permeability or saturation magnetic flux density, can be easily controlled by adjusting the content of soft magnetic powder in the resin. In particular, the content of soft magnetic powder can be easily adjusted to be low, and the magnetic permeability can be easily reduced. Although the composite material compact has a lower magnetic permeability than the pressed powder compact, it is difficult to become magnetically saturated under a large current operating environment and has low iron loss. The composite material compact can be easily molded into a complex shape compared to the pressed powder compact.

[0053] The soft magnetic powder constituting the composite material compact is the same as the soft magnetic powder constituting the above-mentioned powder compact. The content of the soft magnetic powder in the composite material compact is, for example, 20% by volume or more and 80% by volume or less, assuming the composite material to be 100% by volume.

[0054] The resin constituting the composite material molded body is, for example, a thermosetting resin or a thermoplastic resin. The thermosetting resin is, for example, an epoxy resin, a phenol resin, a silicone resin, or a urethane resin. The thermoplastic resin is, for example, a polyphenylene sulfide (PPS) resin, a polybutylene terephthalate (PBT), a polyamide (PA) resin, a liquid crystal polymer (LCP), a polyimide (PI) resin, or a fluororesin. The polyamide resin is, for example, nylon 6, nylon 66, or nylon 9T. The content of the resin in the composite material molded body is, for example, 20% by volume or more and 80% by volume or less, assuming that the composite material is 100% by volume.

[0055] The composite material may contain a filler in addition to the resin. The filler contributes to improving heat dissipation. For example, a powder made of a non-magnetic material such as ceramics or carbon nanotubes can be used as the filler. For example, the ceramics is an oxide, nitride, or carbide of a metal or non-metal. An example of an oxide is alumina, silica, or magnesium oxide. An example of a nitride is silicon nitride, aluminum nitride, or boron nitride. An example of a carbide is silicon carbide.

[0056] <Second Block> Each of the second block parts 120A, 120B, 120C has a side surface facing either the inner surface 92 or the outer surface 93 (FIG. 6) of the winding part 90. As shown in FIG. 2, each of the second block parts 120A, 120B, 120C is arranged so as to face the side surface of the adjacent second block part 120A, 120B, 120C. Each of the second block parts 120A, 120B, 120C has a plurality of side surfaces. In each of the second block parts 120A, 120B, 120C, it is sufficient that any one of the plurality of side surfaces faces the side surface of the adjacent second block part 120A, 120B, 120C. The second block part 120A arranged inside the winding part 90 has a side surface facing the inner surface 92 of the winding part 90. The second block portions 120B and 120C disposed outside the winding portion 90 have side surfaces facing the outer surface 93 of the winding portion 90.

[0057] Each of the second block portions 120A, 120B, and 120C extends in a direction intersecting the end core portion 5 (FIG. 1) of the first block portion 110. Each of the second block portions 120A, 120B, and 120C in this example extends in a first direction D1.

[0058] The second block portion 120A is a block body arranged to face an inner surface 92 (FIG. 6) of a winding portion 90 of the coil 9 described below. The second block portion 120A of this example includes a part of the middle core portion 21. The second block portion 120A of this example has an I-shape constituted by a part of the middle core portion 21. The middle core portion 21 is constituted by a part of the first block portion 110 and the entire second block portion 120A described above.

[0059] 2, the multiple surfaces constituting the second block portion 120A have an end surface 123A facing the first block portion 110. The end surface 123A is a surface joined to the end surface 113 of the first block portion 110.

[0060] The second block portion 120B is a block body arranged to face the outer surface 93 (FIG. 6) of the wound portion 90. The second block portion 120B includes a side core portion 3. The second block portion 120B has an I-shape formed by the side core portions 3. The multiple surfaces constituting the second block portion 120B also have an end surface 123B facing the first block portion 110, similar to the second block portion 120A.

[0061] The second block portion 120C is a block body arranged to face the outer surface 93 (FIG. 6) of the wound portion 90. The second block portion 120C includes a side core portion 4. The second block portion 120C has an I-shape formed by the side core portions 4. The multiple surfaces constituting the second block portion 120C also have an end surface 123C facing the first block portion 110, similar to the second block portion 120A.

[0062] <Protrusion> The end faces 123A, 123B, and 123C include protrusions 125 and 126. The protrusions 125 and 126 are provided on the edges of the end faces 123A, 123B, and 123C. The protrusions 125 and 126 are provided at positions facing each other in the third direction D3 on the edges. The protrusions 125 and 126 protrude from the end faces 123A, 123B, and 123C toward the end face 113 of the first portion 11. The protrusions 125 and 126 protrude in the first direction D1.

[0063] The protrusion 125 is provided so as to overlap the low step 115 provided in the first portion 11. The protrusion 125 is provided corresponding to the low step 115. The protrusion 125 of this example is provided continuously along the entire length of one side constituting the end faces 123A, 123B, 123C. The protrusion 125 of this example is a strip-shaped piece extending along the one side. The protrusion 125 of this example is a strip-shaped piece extending along the second direction D2. The protrusion length of the protrusion 125 corresponds to the width of the low step 115. The width of the low step 115 is the length of the low step 115 along the first direction D1. The protrusion 125 of this example is provided so as to fill the low step 115. When the protrusion 125 is provided so as to fill the lower step 115, the outer surface of the first section 11 and the outer surface of the second section 12 at the joint between the lower step 115 and the protrusion 125 are flush with each other.

[0064] The protrusion 125 provided on the end face 123A further includes extensions 127 that partially protrude from both ends of the protrusion 125 toward the end face 113 of the first section 11. The extensions 127 are protruding pieces extending along the first direction D1. The extensions 127 are also provided so as to fill the lower step 115.

[0065] The protrusion 125 provided on the end surface 123B further includes extensions 127 partially protruding in different directions from each end of the protrusion 125. The extensions 127 provided on the first end of the protrusion 125 protrude toward the end surface 113 of the first section 11. The extensions 127 provided on the first end of the protrusion 125 are protruding pieces extending along the first direction D1. The extensions 127 provided on the second end of the protrusion 125 further protrude along the length of the protrusion 125. The extensions 127 provided on the second end of the protrusion 125 are protruding pieces extending along the second direction D2. The first end of the protrusion 125 is located distal to the middle core portion 21 than the second end. The second end of the protrusion 125 is located proximal to the middle core portion 21 than the first end. All of the extensions 127 are provided to fill the low step portion 115.

[0066] Like the protrusion 125 provided on the end face 123B, the protrusion 125 provided on the end face 123C also further includes extension parts 127 partially protruding in different directions from each end of the protrusion 125. The protrusion 125 provided on the end face 123C is provided symmetrically in the second direction D2 with the protrusion 125 provided on the end face 123B.

[0067] The protrusion 126 is provided so as to overlap the low step 116 provided in the first portion 11. The protrusion 126 is provided corresponding to the low step 116. The protrusion 126 of this example is provided continuously over the entire length of one side constituting the end faces 123A, 123B, 123C. The protrusion 126 of this example is a strip-shaped piece extending along the one side. The protrusion 126 of this example is a strip-shaped piece extending along the second direction D2. The protrusion length of the protrusion 126 corresponds to the width of the low step 116. The width of the low step 116 is the length of the low step 116 along the first direction D1. The protrusion 126 of this example is provided so as to fill the low step 116. When the protrusion 126 is provided so as to fill the lower step 116, the outer surface of the first portion 11 and the outer surface of the second portion 12 are flush with each other at the joint between the lower step 116 and the protrusion 126. Like the protrusion 125, the protrusion 126 also includes an extension portion 127 formed of a protruding piece extending along the first direction D1 or the second direction D2.

[0068] The first portion 11 and the second portion 12A are joined by the mutually facing end faces 113, 123A, and by the low step portions 115, 116 and the protrusions 125, 126. The first portion 11 and the second portion 12B are joined by the mutually facing end faces 113, 123B, and by the low step portions 115, 116 and the protrusions 125, 126. The first portion 11 and the second portion 12C are joined by the mutually facing end faces 113, 123C, and by the low step portions 115, 116 and the protrusions 125, 126. The low step portion 115 is provided on the first surface 111, the low step portion 116 is provided on the second surface 112, and the protrusions 125, 126 are provided so as to overlap the low step portions 115, 116. Therefore, the protrusions 125, 126 sandwich the first portion 11 at the lower step portions 115, 116.

[0069] The second regions 12 may include molded bodies made of different composite materials. For example, the second region 12A and the second region 12B may be made of molded bodies made of different composite materials. In this case, the second region 12B and the second region 12C may be made of molded bodies made of the same composite material. If the second region 12B and the second region 12C are made of molded bodies made of the same composite material, the region disposed inside the winding portion 90 (FIG. 5) of the coil 9 described later and the region disposed outside the winding portion 90 are made of molded bodies made of different composite materials. The second region 12A, the second region 12B, and the second region 12C may be made of molded bodies made of different composite materials. The different composite materials are at least partly different in type and content of the constituent materials of the composite material. The different types of constituent materials of the composite material include different types of soft magnetic powder and different types of resin. The different types of soft magnetic powder are, for example, different compositions of the soft magnetic powder. The different contents of the constituent materials of the composite material are different in content of the soft magnetic powder in the resin.

[0070] <Core piece manufacturing method> A method for producing the core piece 1 of the first embodiment will be described with reference to Fig. 4. The method for producing the core piece 1 includes a first step of preparing a mold, a second step of arranging a partial core piece in the mold, and a third step of filling the mold with a composite material. The first step, the second step, and the third step are performed in order.

[0071] [First step] In the first step, a mold 300 is prepared having a first space 310 and a plurality of second spaces 321, 322, 323 that communicate with each other. The first space 310 is a space in which a partial core piece 370, which will be described later, is disposed. In FIG. 4, the partial core piece 370 is disposed in the first space 310. The first space 310 is a space disposed along the second direction D2. In the first space 310 of this example, a portion of the partial core piece 370 corresponding to the end core portion 5 (FIG. 1) is disposed. The first space 310 has a size that allows the end core portion 5 of the partial core piece 370 to fit snugly.

[0072] The second spaces 321, 322, 323 extend in a direction intersecting the first space 310 and are arranged side by side. The second spaces 321, 322, 323 are arranged along the first direction D1. In this example, the length of the second space 321 located in the middle of the three second spaces 321, 322, 323 along the first direction D1 is shorter than the second spaces 322, 323 on both sides. In this example, the lengths of the second spaces 322, 323 on both sides along the first direction D1 are the same. In this example, a part of the second space 321 corresponds to the middle core portion 21 (FIG. 1) of the partial core piece 370. The remaining part of the second space 321 has a size corresponding to the second block portion 120A described above. The second block portion 120A corresponds to the middle core portion 21 described above. The second space 322 has a size corresponding to the second block portion 120B described above. The second block portion 120B corresponds to the above-mentioned side core portion 3. The second space 323 has a size corresponding to the above-mentioned second block portion 120C. The second block portion 120C corresponds to the above-mentioned side core portion 4.

[0073] [Second process] In a second step, the partial core piece 370 is placed in the first space 310. The partial core piece 370 is the above-mentioned first portion 11, and is constituted by a powder compact of soft magnetic powder.

[0074] The partial core piece 370 includes a first block portion and a low step portion 375. The first block portion is the first block portion 110 of the first portion 11 described above, and corresponds to a part of the middle core portion 2 and the end core portion 5. The low step portion 375 is provided on each edge portion of two mutually facing surfaces among the multiple surfaces constituting the first block portion. The low step portion 375 is a portion in which the edge portion of each of the two surfaces is locally lowered. The partial core piece 370 is manufactured by pressure molding a raw material powder containing a soft magnetic powder. The raw material powder is pressed in the direction in which the two surfaces of the resulting partial core piece 370 face each other. During this pressure molding, the low step portion 375 is formed on the edge portion of each of the two surfaces. The two surfaces correspond to the first surface 111 and the second surface 112 of the first portion 11 described above.

[0075] [Third step] In a third step, a composite material in which soft magnetic powder is dispersed in resin is filled into each of the second spaces 321, 322, 323. The composite material is filled into each of the second spaces 321, 322, 323 through a sprue 330, a runner 340, and a gate 350. In this example, three runners 340 and gates 350 are provided corresponding to the three second spaces 321, 322, 323.

[0076] In the third step, the composite material is filled into each of the second spaces 321, 322, 323 so as to overlap the low stage portion 375 of the partial core piece 370. The composite material filled into each of the second spaces 321, 322, 323 covers the end face of the partial core piece 370 and covers the low stage portion 375. The composite material filled into each of the second spaces 321, 322, 323 solidifies while shrinking. The partial core piece 370 becomes the first portion 11, and the composite material filled into each of the second spaces 321, 322, 323 solidifies to become the second portion 12. The composite material solidified so as to overlap the low stage portion 375 becomes the protrusions 125, 126 (FIG. 2). In this example, the extension portion 127 (FIG. 2) is also formed of the composite material solidified so as to overlap the low stage portion 375. Since the low step portion 375 is provided on two surfaces of the first block portion of the partial core piece 370, the protrusions 125, 126 formed by solidification so as to overlap the low step portion 375 sandwich the partial core piece 370 at the low step portion 375.

[0077] In the third step, at least two of the second spaces 321, 322, and 323 can be filled with composite materials different from each other. For example, the second spaces 322 and 323 may be filled with the same composite material, and the second space 321 may be filled with a composite material different from that of the second spaces 322 and 323. The second spaces 321, 322, and 323 may be filled with composite materials different from each other. In this example, since the gates 350 are provided for each of the second spaces 321, 322, and 323, the second spaces 321, 322, and 323 can be filled with composite materials different from each other.

[0078] In the core piece 1 obtained by the above-mentioned core piece manufacturing method, gate marks are formed in each of the second portions 12A, 12B, and 12C. That is, the core piece 1 has three gate marks.

[0079] <Reactor> The reactor 7 of the first embodiment will be described with reference to Figs. 5 and 6. The reactor 7 includes a magnetic core 8 and a coil 9. The magnetic core 8 is configured by combining first core pieces 81 and second core pieces 82. The coil 9 is disposed in a part of the magnetic core 8. One of the features of the reactor 7 of the first embodiment is that at least one of the first core pieces 81 and the second core pieces 82 is the above-mentioned core piece 1. In this example, the first core piece 81 is the above-mentioned core piece 1.

[0080] [Magnetic core] The magnetic core 8 is a magnetic member for forming a ring-shaped magnetic path by excitation of the coil 9. The magnetic core 8 of this example is configured in an overall θ shape by combining first core pieces 81 and second core pieces 82. Below, first the overall shape of the magnetic core 8 will be described, and then the combination of the first core pieces 81 and the second core pieces 82 will be described.

[0081] <Overall shape of magnetic core> The magnetic core 8 includes a middle core portion 2, two side core portions 3 and 4, and two end core portions 5 and 6. In Fig. 6, dashed two-dot lines are drawn at the boundaries between the middle core portion 2 and each of the end core portions 5 and 6. In Fig. 6, the portions of the magnetic core 8 that are made of a compressed powder compact of soft magnetic powder are cross-hatched.

[0082] The middle core portion 2 has a portion disposed inside a winding portion 90 (FIGS. 5 and 6) of the coil 9 described later. The middle core portion 2 in this example is constituted by the middle core portion 21 of the first core piece 81, the middle core portion 22 of the second core piece 82, and a gap. The middle core portion 22 of the second core piece 82 has a cross-sectional area similar to that of the middle core portion 21 of the first core piece 81. The middle core portion 21 and the middle core portion 22 have the same length along the second direction D2. The middle core portion 21 and the middle core portion 22 have the same length along the third direction D3. A gap is provided between the middle core portion 21 of the first core piece 81 and the middle core portion 22 of the second core piece 82. Providing a gap makes it easy to adjust the inductance of the reactor 7. For example, a gap material (not shown) is disposed in the gap. A known material can be used as the gap material. The material constituting the gap material is, for example, non-magnetic ceramics or resin. The gap may be an air gap in which no gap material is disposed. When reactor 7 includes molded resin portion 10 described below, the gap may be filled with resin constituting molded resin portion 10. In this case, the resin constituting molded resin portion 10 serves as a gap material.

[0083] The length of the middle core portion 2 in the first direction D1 is equal to or greater than the length of a winding portion 90 (FIGS. 5 and 6) of the coil 9 described below in the first direction D1. In this example, the length of the middle core portion 2 in the first direction D1 is slightly longer than the length of the winding portion 90 in the first direction D1. In other words, the middle core portion 2 has a portion that is disposed inside the winding portion 90 and a portion that is disposed outside the winding portion 90. Both ends of the middle core portion 2 are located outside the winding portion 90.

[0084] The two side core portions 3, 4 are the first core piece 81, that is, the side core portions 3, 4 of the core piece 1 described above.

[0085] Of the two end core portions 5, 6, one end core portion 5 is the first core piece 81, i.e., the end core portion 5 of the core piece 1 described above. Of the two end core portions 5, 6, one end core portion 6 is the end core portion 6 of the second core piece 82. The end core portion 6 of the second core piece 82 has the same shape and size as the end core portion 5 of the core piece 1.

[0086] In the magnetic core 8, the middle core portion 2, the two side core portions 3 and 4, and the two end core portions 5 and 6 are connected, so that when a coil 9, which will be described later, is excited, magnetic flux flows and a closed magnetic circuit is formed. As shown by the dashed arrows in Fig. 7, the magnetic flux flows from the middle core portion 2 to the end core portion 5, from the end core portion 5 to each of the two side core portions 3 and 4, from each of the side core portions 3 and 4 to the end core portion 6, and from the end core portion 6 to the middle core portion 2.

[0087] <combination> The first core piece 81 and the second core piece 82 are split pieces obtained by splitting the magnetic core 8 so that the magnetic core 8 is separated in the first direction D1. In this example, the first core piece 81 has an E-shape, and the second core piece 82 has a T-shape. By combining the E-shaped first core piece 81 and the T-shaped second core piece 82, the magnetic core 8 has a θ-shape.

[0088] The first core lamination 81 of this example is the above-mentioned core lamination 1 and includes a first portion 11 and a second portion 12 .

[0089] The second core piece 82 of this example is composed of a powder compact. That is, the second core piece 82 of this example has only the first portion 11. The second core piece 82 may be composed of the first portion 11, or may be composed of a composite of the first portion 11 and the second portion 12. When the second core piece 82 is composed of a composite of the first portion 11 and the second portion 12, the first portion 11 has the end core portion 5, and the second portion 12 has the middle core portion 22. The first portion 11 and the second portion 12 may be joined at the end faces 113, 123A, 123B, and 123C, as in the above-mentioned core piece 1, and may be joined at the low step portions 115, 116 and the protrusions 125, 126.

[0090] The shape of the second core pieces 82 is not particularly limited. The shape of the second core pieces 82 may be, for example, E-shaped. The E-shaped second core pieces 82 include a middle core portion, two side core portions, and an end core portion. In this case, the lengths of the middle core portion and the two side core portions of the first core piece 81 along the first direction D1, and the lengths of the middle core portion and the two side core portions of the second core piece 82 along the first direction D1 may be appropriately adjusted.

[0091] 〔coil〕 The coil 9 includes at least one winding portion 90. The coil 9 in this example includes one winding portion 90. The winding portion 90 is formed by winding one wire in a spiral shape. Both ends of the wire are pulled out from each end of the winding portion 90. Terminal fittings (not shown) are attached to both ends of the wire pulled out from the winding portion 90. An external device (not shown) is connected to the terminal fittings. In Figs. 5 and 6, only the winding portion 90 is shown, and the ends of the wire are omitted.

[0092] The winding may be a known winding. The winding in this example is a coated rectangular wire made of a conductor wire having an insulating coating. The conductor wire is made of, for example, a rectangular copper wire. The insulating coating is made of, for example, enamel. The winding portion 90 in this example is an edgewise coil made by edgewise winding the coated rectangular wire.

[0093] The shape of the winding portion 90 is a square tube shape. That is, the shape of the end face 91 of the winding portion 90 in this example is a rectangular frame shape. The winding portion 90 has an inner side surface 92 and an outer side surface 93. The inner side surface 92 faces the middle core portion 2. A gap exists between the inner side surface 92 and the outer peripheral surface of the middle core portion 2. When the reactor 7 has a molded resin portion 10 described later, this gap is filled with resin constituting the molded resin portion 10. The outer side surface 93 faces the side core portions 3 and 4. The end face 91 faces the end core portions 5 and 6. The corners of the winding portion 90 in this example are rounded. When the winding portion 90 has a square tube shape, the contact area between the winding portion 90 and the installation object is likely to be large compared to when the winding portion is a cylinder with the same cross-sectional area. When the contact area between the winding portion 90 and the installation object is large, the heat dissipation performance of the reactor 7 is improved. When the contact area between the winding portion 90 and the installation target is large, the installation state of the winding portion 90 relative to the installation target is likely to be stable.

[0094] [Molded resin part] The reactor 7 may include a molded resin part 10 as shown in FIG. 5. In FIG. 5, the appearance of the molded resin part 10 is shown by a two-dot chain line for easy understanding. The molded resin part 10 covers at least a part of the magnetic core 8. The molded resin part 10 has a function of protecting the magnetic core 8 from the external environment. The molded resin part 10 may further cover the coil 9. That is, the molded resin part 10 is provided so as to cover at least a part of the assembly of the magnetic core 8 and the coil 9. The molded resin part 10 integrates the magnetic core 8 and the coil 9. A part of the outer circumferential surface of the magnetic core 8 or at least a part of the outer circumferential surface of the coil 9 may be exposed from the molded resin part 10.

[0095] If the molded resin part 10 is provided between the magnetic core 8 and the coil 9, it is easy to ensure insulation between the magnetic core 8 and the coil 9. If the molded resin part 10 is provided between the middle core part 21 of the first core piece 81 and the middle core part 22 of the second core piece 82, the molded resin part 10 provided therebetween functions as a gap material for the magnetic core 8.

[0096] The resin constituting the molded resin portion 10 is, for example, the same resin as the resin of the composite material described above. The constituent material of the molded resin portion 10 may contain the above-mentioned filler, like the composite material.

[0097] 〔others〕 Although not shown, the reactor 7 may include a holding member. The holding member is disposed between the magnetic core 8 and the coil 9, and has a function of ensuring electrical insulation between the magnetic core 8 and the coil 9. The holding member has a function of defining the relative positions of the magnetic core 8 and the coil 9 and maintaining the positioning state. The holding member is disposed, for example, between the end face 91 of the winding portion 90 and the end core portions 5 and 6. The holding member disposed between the end face 91 of the winding portion 90 and the end core portions 5 and 6 is, for example, a frame-shaped member. The holding member is disposed, for example, between the inner peripheral surface of the winding portion 90 and the outer peripheral surface of the middle core portion 2. The holding member disposed between the inner peripheral surface of the winding portion 90 and the outer peripheral surface of the middle core portion 2 is, for example, a cylindrical member. The holding member disposed between the inner peripheral surface of the winding portion 90 and the outer peripheral surface of the middle core portion 2 is, for example, structured so that the unsolidified constituent resin of the molded resin portion 10 can flow between the winding portion 90 and the middle core portion 2.

[0098] <Embodiment 2> <Core Piece> The core piece 1 of the second embodiment will be described with reference to Figs. 7 and 8. Like the core piece 1 of the first embodiment, the core piece 1 of the second embodiment is also an integral body in which the first portion 11 and the multiple second portions 12 are integrally molded, and the first portion 11 and the multiple second portions 12 made of different materials are well joined. One of the features of the core piece 1 of the second embodiment is that the protrusions 125 provided on each second portion 12 are composed of connecting protrusions 128. The overall shape of the core piece 1 of the second embodiment is similar to that of the core piece 1 of the first embodiment. The following description will focus on the differences from the core piece 1 of the first embodiment.

[0099] [First part] The first block portion 110 of the first section 11 is a block body having a portion arranged to face an end surface 91 (FIG. 6) of the wound portion 90 of the coil 9. The first block portion 110 of this example includes a part of the end core portion 5. The first block portion 110 has an I-shape constituted by a part of the end core portion 5. The length of the first block portion 110 of this example along the third direction D3 is shorter than the length of the end core portion 5 along the third direction D3. In other words, the first section 11 of this example is arranged biased toward the third direction D3 of the end core portion 5.

[0100] The first surface 111 of the first block portion 110 has a low step portion 115. The low step portion 115 is provided on the edge portion of the first surface 111. The low step portion 115 is a portion where the edge portion of the first surface 111 is locally lowered. In this example, the low step portion 115 is provided continuously around the entire circumference of the first surface 111.

[0101] Although not shown, the second surface of the first block portion 110 has a low step portion. The second surface of the first block portion 110 is the surface facing the first surface 111 shown in FIG. 8. The low step portion is provided on the edge portion of the second surface. The low step portion is a portion where the edge portion of the second surface is locally lowered. The low step portion in this example is provided continuously around the entire circumference of the second surface, similar to the low step portion 115 shown in FIG. 8.

[0102] [Second part] The core piece 1 of the second embodiment has three second portions 12A, 12B, and 12C, similarly to the core piece 1 of the first embodiment.

[0103] The second block portion 120A of the second portion 12A includes a middle core portion 21. The second block portion 120A has an I-shape formed by the middle core portion 21. The second block portion 120A has a plurality of faces including an end face 123A facing the first portion 11.

[0104] The second block portion 120B of the second portion 12B includes a side core portion 3. The second block portion 120B has an I-shape formed by the side core portions 3. The multiple surfaces forming the second block portion 120B also have end faces 123B facing the first portion 11, similar to the second block portion 120A.

[0105] The second block portion 120C of the second portion 12C includes a side core portion 4. The second block portion 120C has an I-shape formed by the side core portion 4. The multiple surfaces forming the second block portion 120C also have end faces 123C facing the first portion 11, similar to the second block portion 120A.

[0106] The second block portions 120A, 120B, 120C are block bodies arranged to face an inner surface 92 (FIG. 6) of a winding portion 90 of the coil 9, which will be described later.

[0107] The end faces 123A, 123B, and 123C include protrusions 125 and 126. The protrusions 125 and 126 are provided on the edges of the end faces 123A, 123B, and 123C. The protrusions 125 and 126 are provided at positions facing each other in the third direction D3 on the edges. The protrusions 125 and 126 protrude from the end faces 123A, 123B, and 123C toward the end face 113 of the first portion 11. The protrusions 125 and 126 protrude in the first direction D1.

[0108] The protrusion 125 in this example is a connecting protrusion 128 connected to all of the second parts 12A, 12B, and 12C. The connecting protrusion 128 is provided on the first surface 111 of the first block part 110 so as to overlap continuously with both the low step part 115 and a part other than the low step part 115. The connecting protrusion 128 constitutes a part of the end core part 5. The end core part 5 is constituted by a part of the first block part 110 and the connecting protrusion 128. In other words, the end core part 5 is constituted by a part of the first part 11 and a part of the second part 12. In FIG. 7, the boundary between the middle core part 21 and the end core part 5 and the boundary between the side core parts 3, 4 and the end core part 5 are indicated by two-dot chain lines. At both ends of the connecting protrusion 128 in the second direction D2, an extension part 127 constituted by a protrusion extending along the first direction D1 is provided.

[0109] The protrusions 126 are provided on each of the second portions 12A, 12B, and 12C. The protrusions 126 are provided so as to fill the lower step portions 116. The protrusions 126 have the same configuration as the protrusions 126 described in the first embodiment.

[0110] As shown in Fig. 9, the reactor 7 of the second embodiment includes first core laminations 81 constituted by the core laminations 1 of the second embodiment described above. The configurations of the second core laminations 82 and the coil 9 are similar to those of the first embodiment. In this example, a part of the second portion 12 is disposed so as to face an end face 91 of the coil 9. By disposing a part of the second portion 12 so as to face the end face 91 of the coil 9, the magnetic properties are more excellent even with a large current.

[0111] <Modification> Although not shown, the coil may have two winding parts. In this case, the magnetic core has two inner core parts and two outer core parts. The two inner core parts are provided so as to face the inner surface of the winding part. The two outer core parts are provided so as to connect the end faces of the two inner core parts. The two outer core parts have a portion provided so as to face the end face of each winding part. The core piece constituting the magnetic core is, for example, constituted by a U-shaped block body. The U-shaped core piece is constituted by joining a first part and a second part. For example, the first part is constituted by one outer core part and a part of each of the two inner core parts. The second part is constituted by the remaining parts of the two inner core parts. The first part has a lower step portion, and the second part has a protrusion portion.

[0112] <Embodiment 3> <Converter / power conversion device> The reactor 7 of the above-mentioned embodiment 1 or embodiment 2 can be used for applications that satisfy the following energization conditions. The energization conditions are, for example, a maximum DC current of about 100 A to 1000 A, an average voltage of about 100 V to 1000 V, and an operating frequency of about 5 kHz to 100 kHz. The reactor 7 of embodiment 1 or embodiment 2 is typically 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 including this converter.

[0113] 10, 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, which drives wheels 1250 during 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. In FIG. 10, the charging point of the vehicle 1200 is an inlet, but a form including a plug may also be used.

[0114] 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 about 200V to 300V, to about 400V to 700V when the vehicle 1200 is running, and supplies power to the inverter 1120. During regeneration, the converter 1110 lowers 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. During regeneration, the inverter 1120 converts the AC output from the motor 1220 into DC and outputs it to the converter 1110.

[0115] As shown in FIG. 11, 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 turning the switching elements 1111 on and off. The conversion of the input voltage means stepping up and down the voltage here. 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 prevents changes in the current flowing through the circuit, and has a function of smoothing out changes when the current increases or decreases due to switching operations. The reactor 7 of the first or second embodiment is included as the reactor 1115.

[0116] In addition to the converter 1110, the vehicle 1200 includes a converter 1150 for a power supply device connected to the main battery 1210, and a converter 1160 for an auxiliary power supply connected to the sub-battery 1230 serving as a power source for the auxiliary devices 1240 and the main battery 1210 to convert the high voltage of the main battery 1210 to a low voltage. The converter 1110 typically performs DC-DC conversion, while the converter 1150 for a power supply device and the converter 1160 for an auxiliary power supply perform AC-DC conversion. Some of the converters 1150 for a power supply device perform DC-DC conversion. The reactors of the converter 1150 for a power supply device and the converter 1160 for an auxiliary power supply may have the same configuration as the reactor 7 of the first or second embodiment, and may be appropriately changed in size, shape, or the like. The reactor 7 of the first or second embodiment may also be used as a converter that converts input power and that performs only step-up or step-down. [Explanation of symbols]

[0117] 1 core piece 11 First part 110 First Block Section 111 Front page 112 Second side 113 End face 115,116 Lower part 12,12A,12B,12C Second part 120A, 120B, 120C Second block part 123A,123B,123C end face 125,126 protrusion 127 Extension section 128 Connecting protrusion 2,21,22 Middle Core Section 3,4 Side core part 5,6 End core section 7 Reactor 8 Magnetic Core 81 First core piece 82 Second core piece 9 Coil 90 Winding section 91 End face 92 Inner surface 93 External surface 10 Molded resin part 300 Molds 310 First Space 321,322,323 Second Space 330 sprue 340 Runner 350 Gates 370 Partial core piece 375 Lower section D1 first direction, D2 second direction, D3 third direction 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 power supply 1200 vehicle, 1210 main battery, 1220 motor 1230 Sub-battery, 1240 Auxiliary equipment, 1250 Wheels, 1300 Engine

Claims

1. A core piece for constituting a magnetic core arranged inside and outside a coil, A first portion constituted by a powder compact of soft magnetic powder; a plurality of second portions constituted by a molded body of a composite material in which soft magnetic powder is dispersed in a resin; The first portion is a first block portion having a portion facing an end surface of the coil; a lower step portion formed by locally lowering each edge portion of two opposing faces among the plurality of faces constituting the first block portion, Each of the plurality of second regions is a second block portion having a side surface facing either the inner surface or the outer surface of the coil and arranged to face the side surface of the adjacent second portion; A protrusion is provided on an edge of an end surface constituting the second block portion so as to overlap the lower step portion. Core piece.

2. The plurality of second regions are configured independently of one another; The core piece according to claim 1 , wherein the first portion includes the lower step portion corresponding to the protrusion of each of the second portions.

3. The core piece according to claim 1 or 2, wherein an outer surface of the first portion at a joint between the lower step and the protrusion is flush with an outer surface of each of the second portions.

4. The core piece according to claim 1 or 2, wherein the second portions include molded bodies made of composite materials different from each other.

5. The protrusion includes a connecting protrusion connected to all of the second portions, The core piece according to claim 1, wherein the connecting protrusion is arranged on one of two mutually facing faces among the multiple faces constituting the first block portion so as to overlap continuously with both the low step portion and a portion other than the low step portion.

6. a magnetic core formed by combining first core pieces and second core pieces; a coil disposed in a portion of the magnetic core; At least one of the first core piece and the second core piece is the core piece according to claim 1 or 2. Reactor.

7. A reactor comprising the reactor according to claim 6. converter.

8. A converter comprising: Power conversion equipment.

9. Providing a mold having a first space and a plurality of second spaces that are in communication with each other; A step of disposing a partial core piece constituted by a powder compact of soft magnetic powder in a space including the first space; and filling each of the plurality of second spaces with a composite material in which soft magnetic powder is dispersed in a resin, Each of the second spaces extends in a direction intersecting with the first space and is arranged next to one another, The partial core piece is A first block portion; a lower step portion in which each edge portion of two mutually facing surfaces among the plurality of surfaces constituting the first block portion is locally lowered, In the filling step, the composite material is filled into each of the second spaces so as to overlap the lower step portion. Manufacturing method of the core piece.

10. The method for manufacturing a core piece according to claim 9 , wherein in the filling step, at least two of the second spaces are filled with the composite materials different from each other.

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