Core piece, reactor, converter, power converter, 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 a core piece.

Background Art

[0002] Patent Document 1 discloses a core piece configured by combining a first core piece and a second core piece. The first core piece is composed of a molded body of a composite material in which soft magnetic powder is dispersed in resin. The second core piece is composed of a compacted molded body of soft magnetic powder. The core piece is manufactured by disposing the second core piece in a mold and molding the first core piece around the second core piece. Hereinafter, in the core piece, the portion composed of the compacted molded body is referred to as the first portion, and the portion composed of the molded body of the composite material is referred to as the second portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

[0005] One of the purposes of this disclosure is to provide a core piece in which a first part and a second part made of different materials are well joined together. Another purpose of this disclosure is to provide a reactor comprising the above core piece. Another purpose of this disclosure is to provide a converter comprising the above reactor. Another purpose of this disclosure is to provide a power conversion device comprising the above converter. Another purpose of this disclosure is to provide a method for manufacturing a core piece in which a first part and a second part made of different materials are well joined together. [Means for solving the problem]

[0006] The core piece of the present disclosure is a core piece for constituting a magnetic core disposed inside or outside a coil, and comprises a first portion made of a compacted molded body of soft magnetic powder and a plurality of second portions made of a molded body of a composite material in which soft magnetic powder is dispersed in a resin. The first portion comprises a first block portion having a portion provided to face the end face of the coil, and a lowered portion having locally lowered edges on two faces of the plurality of faces constituting the first block portion that face each other. Each of the plurality of second portions has a side facing either the inner or outer surface of the coil and comprises a second block portion arranged to face the side of an adjacent second portion, and a projection provided on the edge of the end face constituting the second block portion so as to overlap the lowered portion. [Effects of the Invention]

[0007] The core piece of this disclosure is formed by a good bond between a first part and a second part made of different materials. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic perspective view showing a core piece of Embodiment 1. [Figure 2] Figure 2 is a schematic perspective view of the core piece of Embodiment 1 in an exploded state. [Figure 3] Figure 3 is a schematic perspective view showing the first portion of the core piece of Embodiment 1. [Figure 4] Figure 4 is a schematic diagram illustrating the manufacturing method of the core piece according to Embodiment 1. [Figure 5] Figure 5 is a schematic perspective view showing the reactor of Embodiment 1. [Figure 6] Figure 6 is a schematic diagram showing the flow of magnetic flux in the magnetic core of the reactor of Embodiment 1. [Figure 7] Figure 7 is a schematic perspective view showing a core piece of Embodiment 2. [Figure 8] Figure 8 is a schematic perspective view of the core piece of Embodiment 2 in an exploded state. [Figure 9] Figure 9 is a schematic perspective view showing the reactor of Embodiment 2. [Figure 10] Figure 10 is a schematic diagram showing the power supply system of a hybrid vehicle. [Figure 11] Figure 11 is a circuit diagram showing an example of a power conversion device equipped with a converter. [Modes for carrying out the invention]

[0009] [Description of Embodiments in this Disclosure] First, the embodiments of this disclosure will be listed and described.

[0010] (1) A core piece according to the embodiment of the present disclosure is a core piece for constituting a magnetic core disposed inside or outside a coil, comprising: a first portion made of a compacted molded body of soft magnetic powder; and a plurality of second portions made of a molded body of a composite material in which soft magnetic powder is dispersed in a resin. The first portion comprises: a first block portion having a portion provided to face the end face of the coil; and a lowered portion having locally lowered edges on two faces of the plurality of faces constituting the first block portion that face each other. Each of the plurality of second portions has a side facing either the inner or outer surface of the coil, and comprises: a second block portion having a side facing the side of an adjacent second portion; and a projection provided on the edge of the end face constituting the second block portion so as to overlap the lowered portion.

[0011] Powder compacts allow for a higher content of soft magnetic powder compared to composite material compacts. Powder compacts with a high soft magnetic powder content have high permeability but are prone to magnetic saturation. In particular, under high-current operating conditions, powder compacts are prone to magnetic saturation and increased iron loss. Composite material compacts have lower permeability compared to powder compacts but are less prone to magnetic saturation under high-current operating conditions and exhibit low iron loss. Therefore, a core piece composed of a first part made of powder compact and a second part made of composite material exhibits excellent magnetic properties even under high currents.

[0012] The first part, composed of a compacted powder molded body, and the second part, composed of a composite material molded body, are joined primarily at their opposing end faces. In addition to the joints at the end faces described above, the first and second parts are also joined at the stepped portion provided in the first part and the protruding portion provided in the second part. The stepped portion is provided on two sides of the first block portion of the first part, and the protruding portion is provided so as to overlap each stepped portion. In this configuration, the protruding portion sandwiches the first part at the stepped portion. The core piece described above is manufactured by filling a mold containing a partial core piece with composite material, as will be described later. The partial core piece becomes the first part. The composite material filled in the mold solidifies while shrinking. The composite material that has solidified so as to overlap the stepped portion of the first part becomes the protruding portion. Because the protruding portion is provided so as to overlap the stepped portion, the first and second parts of the core piece are well joined together, even though they are made of different materials.

[0013] (2) In the core piece described in (1) above, the plurality of second parts are configured independently of each other, and the first part may be provided with the lower step portion corresponding to each of the protrusions of the plurality of second parts.

[0014] Even if multiple second parts are constructed independently of each other, the first part is provided with a lower step corresponding to the protrusion of each second part, thereby ensuring good jointing between the first and second parts.

[0015] (3) In the core piece according to the above (1) or (2), the outer surface of the first part and the outer surface of each of the plurality of second parts at the joint between the lower step part and the protrusion part may be flush.

[0016] If the outer surface of the first part and the outer surface of each second part at the joint are flush, it is difficult for the joint to interfere with a member facing the core piece, such as a coil.

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

[0018] The plurality of second parts include, for example, a part arranged to face the inner surface of the coil and a part arranged to face the outer surface of the coil. The part arranged to face the inner surface of the coil is a part arranged inside the coil. The part arranged to face the outer surface of the coil is a part arranged outside the coil. If the part arranged inside the coil and the part arranged outside the coil are made of molded bodies of different composite materials, it is easy to adjust the magnetic characteristics of the entire core piece.

[0019] (5) In the core piece according to the above (1), the protrusion part includes a connecting protrusion connected to all of the plurality of second parts, and the connecting protrusion may be provided so as to continuously overlap both the lower step part and a location other than the lower step part on one of two opposite surfaces among the plurality of surfaces constituting the first block part.

[0020] If the connecting protrusion is provided so as to overlap not only the lower step part but also a location other than the lower step part on one of the two surfaces, a large contact area between the first part and the second part can be ensured, and the first part and the second part are more likely to be joined well. If the connecting protrusion is provided so as to overlap a location other than the lower step part, a part of the second part is arranged to face the end face of the coil. By arranging a part of the second part to face the end face of the coil, even with a large current, the magnetic characteristics are more excellent.

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

[0022] A reactor comprising a magnetic core containing the above-mentioned core piece exhibits excellent magnetic properties.

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

[0024] Converters equipped with the above-mentioned reactor exhibit excellent magnetic properties.

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

[0026] A power conversion device equipped with the above converter exhibits excellent magnetic properties.

[0027] (9) A method for manufacturing a core piece according to an embodiment of the present disclosure comprises the steps of: preparing a mold having a first space and a plurality of second spaces communicating with each other; arranging a partial core piece made of a compacted molded body 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 the first space and is arranged side by side with each other. The partial core piece comprises a first block portion and a lowered portion in which the edges of two faces of a plurality of faces constituting 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 lowered portion.

[0028] In the above method for manufacturing a core piece, a partial core piece is placed in a space including the first space of the mold, and a composite material is filled into the second space. The composite material covers the end face of the partial core piece and also covers the lower step portion. The composite material filled into the mold solidifies while shrinking. The partial core piece becomes the first part, and the composite material filled into the second space solidifies to become the second part. The composite material that solidifies so as to overlap the lower step portion becomes a protrusion. The lower step portion is provided on two sides of the first block portion of the partial core piece, and the protrusion is formed so as to overlap each lower step portion. In this configuration, the protrusion sandwiches the partial core piece at the lower step portion. In the above method for manufacturing a core piece, by solidifying the composite material so as to sandwich two sides of the partial core piece in addition to the end face, it is possible to manufacture a core piece in which two parts of different materials are well joined together.

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

[0030] The composite material filling each of the multiple second spaces constitutes, for example, a portion facing the inner surface of the coil and a portion facing the outer surface of the coil. The portion facing the inner surface of the coil is the portion located inside the coil. The portion facing the outer surface of the coil is the portion located outside the coil. If the portions located inside and outside the coil are made of molded composite materials that are different from each other, it becomes easier to adjust the magnetic properties of the entire core piece.

[0031] [Details of the embodiments of this disclosure] Specific examples of embodiments of this disclosure will be described below with reference to the drawings. Identical reference numerals in the drawings indicate identical parts. In each drawing, some parts of the configuration may be exaggerated or simplified for ease of explanation. The dimensional ratios of parts in the drawings may also differ from those of the actual parts. The present invention is not limited to these examples, but is shown in the claims, and all modifications within the meaning and scope equivalent to the claims are intended.

[0032] <Embodiment 1> ≪Core Piece≫ The core piece 1 of Embodiment 1 will be described with reference to Figures 1 to 3. The core piece 1 is a component of the reactor 7, which will be described later. As shown in Figure 1, the core piece 1 is a single piece formed by integrally molding a first part 11 and a plurality of second parts 12. One of the features of the core piece 1 of Embodiment 1 is that it has a configuration in which the first part 11 and the plurality of second parts 12, which are made of different materials, are well joined together. In the core piece 1 of Embodiment 1, the plurality of second parts 12 are constructed independently of each other, and each second part 12 is joined to the first part 11. Below, the overall shape of the core piece 1 will be described first, and then the configuration of the first part 11 and each of the second parts 12 will be described.

[0033] [Overall shape of the core piece] The core piece 1 comprises 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 composed of the middle core portion 21, the two side core portions 3 and 4, and the end core portion 5. In Figure 1, a dashed line is drawn at the boundary between the middle core portion 21 and the end core portion 5.

[0034] In the following explanation, the first direction D1, the second direction D2, and the third direction D3 may be used. The first direction D1 is the direction away from the joint surface with the end core 5 along the axis of the middle core 21 in the middle core 21. The second direction D2 is the direction from side core 3 to side core 4 along the alignment of the middle core 2 and the two side core 3 and 4. The third direction D3 is the direction from the bottom surface to the top surface of core piece 1. The bottom surface of core piece 1 includes the second surface 112 of the first block 110, which constitutes the first part 11 described later with reference to Figures 2 and 3. The top surface of core piece 1 includes the first surface 111 of the first block 110. The first direction D1, the second direction D2, and the third direction D3 are orthogonal 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. In the following, the opposite directions of the first direction D1, second direction D2, and third direction D3 will also be referred to as the first direction D1, second direction D2, and third direction D3, respectively.

[0035] The middle core portion 21 has a portion that is located inside the winding portion 90 of the coil 9 (Figures 5 and 6), which will be described later. The middle core portion 21 is a portion that extends in a direction intersecting with the end core portion 5 and may have a portion that is located outside the winding portion 90. In other words, the middle core portion 21 may have a portion located inside the winding portion 90 and a portion located outside the winding portion 90. The shape of the middle core portion 21 is roughly corresponding to the inner circumference shape of the winding portion 90. In this example, the middle core portion 21 is a rectangular block. The corners of the middle core portion 21 are rounded to follow the corners of the winding portion 90.

[0036] The two side core sections 3 and 4 are arranged alongside the middle core section 21 outside the winding section 90 of the coil 9 (Figures 5 and 6), which will be described later. The two side core sections 3 and 4 are arranged so as to sandwich the middle core section 21 while maintaining a gap between them. The shape of each side core section 3 and 4 is not limited to the shape of the middle core section 21. In this example, each side core section 3 and 4 is a rectangular block. In this example, the shape and dimensions of the two side core sections 3 and 4 are identical. In this example, the length of each side core section 3 and 4 along the first direction D1 is longer than the length of the middle core section 21 along the first direction D1. The length of each side core section 3 and 4 along the first direction D1 may be equal to or less than the length of the middle core section 21 along the first direction D1. In this example, the length of each side core section 3 and 4 along the second direction D2 is shorter than the length of the middle core section 21 along the second direction D2. In this example, the sum of the lengths of each side core section 3 and 4 along the second direction D2 is shorter than the length of the middle core section 21 along the second direction D2. The sum of the lengths of each side core section 3 and 4 along the second direction D2 may be equal to or greater than the length of the middle core section 21 along the second direction D2. In this example, the length of each side core section 3 and 4 along the third direction D3 is the same as the length of the middle core section 21 along the third direction D3. The length of each side core section 3 and 4 along the third direction D3 may be shorter or longer than the length of the middle core section 21 along the third direction D3. The shapes and dimensions of the two side core sections 3 and 4 may be different.

[0037] The end core section 5 is positioned outside the winding section 90 of the coil 9 (Figures 5 and 6), which will be described later, to connect the middle core section 21 and the two side core sections 3 and 4. The shape of the end core section 5 does not need to be such that it connects the middle core section 21 and the two side core sections 3 and 4. In this example, the end core section 5 is a rectangular block. The length of the end core section 5 along the third direction D3 is the same as the length of the middle core section 21 along the third direction D3. The length of the end core section 5 along the third direction D3 may be shorter or longer than the length of the middle core section 21 along the third direction D3.

[0038] [First part] The first part 11 is made of a compacted molded body of soft magnetic powder. As shown in Figures 2 and 3, the first part 11 comprises a first block section 110 and lower stepped sections 115 and 116.

[0039] <Material> The compacted body constituting the first part 11 is formed by pressure molding a raw material powder containing soft magnetic powder. Compared to the composite material molded body described later, the compacted body can have a higher content of soft magnetic powder. A compacted body with a high content of soft magnetic powder has high magnetic permeability. The content of soft magnetic powder in the compacted body is, for example, more than 80% by volume, and more specifically, 85% or more by volume, when the compacted body is considered as 100% by volume. The raw material powder may also contain a lubricant.

[0040] Soft magnetic powder is composed of, for example, particles of soft magnetic metal, coated particles, or particles of soft magnetic nonmetal. Coated particles consist of soft magnetic metal particles and an insulating coating provided on the outer circumference of the soft magnetic metal particles. Soft magnetic metals are, for example, pure iron or iron-based alloys. Iron-based alloys are, for example, Fe-Si alloys or Fe-Ni alloys. The insulating coating is, for example, a phosphate. Soft magnetic nonmetals are, for example, ferrite.

[0041] <First Block Section> The first block portion 110 is a block body having a portion that faces the end face 91 (Figure 6) of the winding portion 90 of the coil 9, which will be described later. In this example, the first block portion 110 comprises a part of the middle core portion 21 and an end core portion 5. In this example, the first block portion 110 has a T-shape composed of a part of the middle core portion 21 and an end core portion 5.

[0042] The multiple surfaces constituting the first block portion 110 have a first surface 111, a second surface 112, and an end surface 113, as shown in Figures 2 and 3. The first surface 111 and the second surface 112 are surfaces that face 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 Figure 2. The end surface 113 is a surface joined to the end surfaces 123A, 123B, and 123C.

[0043] <Low section> The first surface 111 is provided with a lowered portion 115. The lowered portion 115 is located at the edge of the first surface 111. The lowered portion 115 is a locally lowered portion of the edge of the first surface 111. In other words, the lowered portion 115 is a portion that is lower than other parts of the first surface 111, creating a step. In the first part 11 having the lowered portion 115, the density near the edge of the first surface 111 is the same as the density in other parts. In the first part 11 having the lowered portion 115, there are fewer cracks at the edge of the first surface 111.

[0044] The lower step portion 115 may be provided continuously around the entire circumference of the first surface 111. In this example, the lower step portion 115 is provided on the edge of the first surface 111 extending from the end core portion 5 to the middle core portion 21. When the lower step portion 115 is provided continuously around the entire circumference of the first surface 111, good bonding between the lower step portion 115 and the protrusions 125 is ensured, regardless of the number of second portions 12, i.e., the number of protrusions 125. When the lower step portion 115 is provided continuously around the entire circumference of the first surface 111, a part of the lower step portion 115 is covered by the protrusions 125. When the lower step portion 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 portion of the lower step portion 115 may be covered by the molded resin portion 10.

[0045] The surface of the first surface 111 is flat except for the edges. The surface extending from this flat surface to the lower step 115 is inclined. The bottom surface of the lower step 115 is flat. In this example, a lower step 115 is provided that has a frame-shaped flat surface surrounding the outside of the inclined surface. The width of the flat surface that makes up 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.

[0046] The step difference in the lower step portion 115 relative to the edges of the first surface 111 is, for example, 1 mm to 10 mm. This step difference is the depth of the lower step portion 115. If the step difference in the lower step portion 115 is 1 mm or more, a good connection with the protrusion 125 of the second portion 12, which will be described later, is easily ensured. If the step difference in the lower step portion 115 is 10 mm or less, a good end face 113 is relatively easily ensured. The step difference in the lower step portion 115 may be 1 mm to 7 mm, 1 mm to 4 mm, or 1 mm to 3 mm.

[0047] As shown in Figure 3, the second surface 112 includes a stepped portion 116. The stepped portion 116 is provided on the edge of the second surface 112. The stepped portion 116 is a locally lowered portion of the edge of the second surface 112. In other words, the stepped portion 116 is a portion that is lower than other parts of the second surface 112, creating a step. In the first part 11 having the stepped portion 116, the density near the edge of the second surface 112 is the same as the density in other parts. In the first part 11 having the stepped portion 116, there are fewer cracks on the edge of the second surface 112.

[0048] The lower step portion 116 may be provided continuously around the entire circumference of the second surface 112. In this example, the lower step portion 116 is provided on the edge of the second surface 112 extending from the end core portion 5 to the middle core portion 21 shown in Figure 1. When the lower step portion 116 is provided continuously around the entire circumference of the second surface 112, good bonding between the lower step portion 116 and the protrusions 126 is ensured, regardless of the number of second portions 12 shown in Figure 2, i.e., the number of protrusions 126. When the lower step portion 116 is provided continuously around the entire circumference of the second surface 112, a part of the lower step portion 116 is covered by the protrusions 126. When the lower step portion 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 portion of the lower step portion 116 may be covered by the molded resin portion 10 shown in Figure 5.

[0049] The second surface 112 is flat except for its edges. The surface extending from this flat surface to the lower step 116 is inclined. The bottom surface of the lower step 116 is flat. In this example, a lower step 116 is provided that has a frame-shaped flat surface surrounding the outside of the inclined surface. The width of the flat surface that makes up the bottom surface of the lower step 116 is very narrow. In the second surface 112 of this example, the end core portion 5 and the middle core portion 21 are flush.

[0050] The step difference in the lower step portion 116 relative to the second surface 112, excluding the edge, is, for example, 1 mm to 10 mm. This step difference is the depth of the lower step portion 116. If the step difference in the lower step portion 116 is 1 mm or more, a good connection with the protrusion 126 of the second part 12, which will be described later, is easily ensured. If the step difference in the lower step portion 116 is 10 mm or less, a relatively good end face 113 is easily ensured. The step difference in the lower step portion 116 may be 1 mm to 7 mm, 1 mm to 4 mm, or 1 mm to 3 mm.

[0051] [Second part] Each of the multiple second parts 12 is composed of a molded composite material in which soft magnetic powder is dispersed in resin. The core piece 1 in this example comprises three second parts 12A, 12B, and 12C, as shown in Figure 2. Second part 12A comprises a second block part 120A and protrusions 125 and 126. Second part 12B comprises a second block part 120B and protrusions 125 and 126. Second part 12C comprises a second block part 120C and protrusions 125 and 126. The material of the second parts 12A, 12B, and 12C is the same. Hereinafter, second parts 12A, 12B, and 12C that have the same configuration will be referred to as second part 12 without distinction.

[0052] <Material> The molded composite material constituting the second part 12 is manufactured by filling a mold with a raw material in which soft magnetic powder is mixed and dispersed in an unsolidified resin, and then solidifying the resin. The composite material allows for easy control of its magnetic properties, such as permeability or saturation magnetic flux density, by adjusting the content of soft magnetic powder in the resin. 。 In particular, composite materials allow for easy adjustment of the soft magnetic powder content, making it easier to achieve low magnetic permeability. Although molded composite materials have lower magnetic permeability compared to compacted powder molded materials, they are less prone to magnetic saturation under high-current operating environments and exhibit low iron loss. Molded composite materials are also easier to mold into complex shapes compared to compacted powder molded materials.

[0053] The soft magnetic powder constituting the molded composite material is the same as the soft magnetic powder constituting the compacted powder molded body described above. The content of soft magnetic powder in the molded composite material is, for example, 20% to 80% by volume, when the composite material is considered to be 100% by volume.

[0054] The resin constituting the molded composite material is, for example, a thermosetting resin or a thermoplastic resin. Thermosetting resins include, for example, epoxy resins, phenolic resins, silicone resins, or urethane resins. Thermoplastic resins include, for example, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT), polyamide (PA) resin, liquid crystal polymer (LCP), polyimide (PI) resin, or fluororesin. Polyamide resins include, for example, nylon 6, nylon 66, or nylon 9T. The resin content in the molded composite material is, for example, 20% to 80% by volume, when the composite material is considered to be 100% by volume.

[0055] The composite material may contain fillers in addition to the resin. The fillers contribute to improved heat dissipation. The fillers can be powders made of non-magnetic materials such as ceramics or carbon nanotubes. Ceramics are, for example, metallic or nonmetallic oxides, nitrides, or carbides. Examples of oxides are alumina, silica, or magnesium oxide. Examples of nitrides are silicon nitride, aluminum nitride, or boron nitride. An example of a carbide is silicon carbide.

[0056] <Second Block Section> Each second block section 120A, 120B, and 120C has a side facing either the inner surface 92 or the outer surface 93 (Figure 6) of the winding section 90. Each second block section 120A, 120B, and 120C is arranged so as shown in Figure 2 that it faces the side of an adjacent second block section 120A, 120B, and 120C. Each second block section 120A, 120B, and 120C has multiple sides. In each second block section 120A, 120B, and 120C, it is sufficient that any of the multiple sides face the side of an adjacent second block section 120A, 120B, and 120C. The second block section 120A, which is located inside the winding section 90, has a side facing the inner surface 92 of the winding section 90. The second block sections 120B and 120C, which are located outside the winding section 90, have sides that face the outer surface 93 of the winding section 90.

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

[0058] The second block section 120A is a block body positioned to face the inner surface 92 (Figure 6) of the winding section 90 of the coil 9, which will be described later. In this example, the second block section 120A comprises a part of the middle core section 21. In this example, the second block section 120A has an I-shaped form composed of a part of the middle core section 21. The middle core section 21 is composed of a part of the first block section 110 and the entirety of the second block section 120A.

[0059] As shown in Figure 2, the multiple surfaces constituting the second block portion 120A have end faces 123A facing the first block portion 110. The end faces 123A are surfaces joined to the end faces 113 of the first block portion 110.

[0060] The second block section 120B is a block body positioned to face the outer surface 93 (Figure 6) of the winding section 90. The second block section 120B includes a side core section 3. The second block section 120B has an I-shaped form formed by the side core section 3. The multiple surfaces constituting the second block section 120B also have end faces 123B facing the first block section 110, similar to the second block section 120A.

[0061] The second block section 120C is a block body positioned to face the outer surface 93 (Figure 6) of the winding section 90. The second block section 120C includes a side core section 4. The second block section 120C has an I-shaped form composed of the side core section 4. of The multiple surfaces that make up the block also have end faces 123C that face the first block 110, similar to the second block 120A.

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

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

[0064] The projection 125 provided on the end face 123A further comprises extensions 127 that partially protrude toward the end face 113 of the first portion 11 from both ends of the projection 125. These extensions 127 are projections that extend along the first direction D1. These extensions 127 are also provided to fill the lower step portion 115.

[0065] The projection 125 provided on the end face 123B further comprises extensions 127 that project from each end of the projection 125 in partially different directions. The extension 127 provided at the first end of the projection 125 projects toward the end face 113 of the first section 11. The extension 127 provided at the first end of the projection 125 is a projection that extends along the first direction D1. The extension 127 provided at the second end of the projection 125 further projects along the length of the projection 125. The extension 127 provided at the second end of the projection 125 is a projection that extends along the second direction D2. The first end of the projection 125 is located distal to the middle core section 21 than the second end. The second end of the projection 125 is located proximal to the middle core section 21 than the first end. Both extensions 127 are provided to fill the lower section 115.

[0066] The projection 125 provided on the end face 123C, like the projection 125 provided on the end face 123B, further includes extensions 127 that project from each end of the projection 125 in partially different directions. The projection 125 provided on the end face 123C is provided symmetrically with respect to the projection 125 provided on the end face 123B in the second direction D2.

[0067] The projection 126 is provided so as to overlap the lower step portion 116 provided on the first portion 11. The projection 126 is provided in correspondence with the lower step portion 116. In this example, the projection 126 is provided continuously along the entire length of one side that constitutes the end faces 123A, 123B, and 123C. In this example, the projection 126 is a strip-shaped piece extending along the above-mentioned side. In this example, the projection 126 is a strip-shaped piece extending along the second direction D2. The projection length of the projection 126 corresponds to the width of the lower step portion 116. The width of the lower step portion 116 is the length along the first direction D1 in the lower step portion 116. In this example, the projection 126 is provided so as to fill the lower step portion 116. When the projection 126 is provided 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 at the joint between the lower step 116 and the projection 126. The projection 126, like the projection 125, also includes an extension portion 127 composed of a projection extending along the first direction D1 or the second direction D2.

[0068] The first part 11 and the second part 12A are joined by their opposing end faces 113, 123A, and by the stepped sections 115, 116 and the protrusions 125, 126. The first part 11 and the second part 12B are joined by their opposing end faces 113, 123B, and by the stepped sections 115, 116 and the protrusions 125, 126. The first part 11 and the second part 12C are joined by their opposing end faces 113, 123C, and by the stepped sections 115, 116 and the protrusions 125, 126. The stepped section 115 is provided on the first surface 111, the stepped section 116 is provided on the second surface 112, and the protrusions 125, 126 are provided so as to overlap the stepped sections 115, 116. Therefore, the protrusions 125 and 126 sandwich the first portion 11 at the lower steps 115 and 116.

[0069] Multiple second parts 12 may include molded bodies made of different composite materials. For example, second part 12A and second part 12B may be made of molded bodies of different composite materials. In this case, second part 12B and second part 12C may be made of molded bodies of the same composite material. If second part 12B and second part 12C are made of molded bodies of the same composite material, the part located inside the winding portion 90 (Figure 5) of the coil 9 (described later) and the part located outside the winding portion 90 will be made of molded bodies of different composite materials. Second part 12A, second part 12B, and second part 12C may be made of molded bodies of different composite materials. Different composite materials mean that at least some of the types and contents of the constituent materials of the composite materials are different. Different types of constituent materials of the composite materials include different types of soft magnetic powder and different types of resin. Different types of soft magnetic powder mean, for example, different compositions of soft magnetic powder. Different contents of constituent materials of the composite materials mean different contents of soft magnetic powder in the resin.

[0070] ≪Method for manufacturing core pieces≫ Referring to Figure 4, the manufacturing method of the core piece 1 of Embodiment 1 will be described. The manufacturing method of the core piece 1 comprises a first step of preparing a mold, a second step of placing a partial core piece in the mold, and a third step of filling the mold with composite material. The first, second, and third steps 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 the space in which the partial core piece 370, described later, is arranged. In Figure 4, the partial core piece 370 is arranged in the first space 310. The first space 310 is a space arranged along the second direction D2. In this example, the first space 310 is where the portion corresponding to the end core portion 5 (Figure 1) of the partial core piece 370 is arranged. The first space 310 is sized to fit the end core portion 5 of the partial core piece 370 perfectly.

[0072] Each of the second spaces 321, 322, and 323 extends in a direction intersecting the first space 310 and is arranged side by side with the others. Each of the second spaces 321, 322, and 323 is a space arranged along the first direction D1. In this example, the length of the second space 321, which is located in the middle of the three second spaces 321, 322, and 323, along the first direction D1 is shorter than that of the second spaces 322 and 323 on either side. In this example, the lengths of the second spaces 322 and 323 on either side along the first direction D1 are the same. In this example, a portion of the second space 321 is arranged in a part corresponding to the middle core portion 21 (Figure 1) of the partial core piece 370. The remainder 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 section 120B corresponds to the side core section 3 described above. The second space 323 has a size corresponding to the second block section 120C described above. The second block section 120C corresponds to the side core section 4 described above.

[0073] [Second process] In the second step, the partial core piece 370 is placed in the first space 310. The partial core piece 370 is the first part 11 described above and is made of a compacted molded body of soft magnetic powder.

[0074] The partial core piece 370 comprises a first block portion and a lowered portion 375. The first block portion is the first block portion 110 of the first part 11 described above, and corresponds to a part of the middle core portion 2 and the end core portion 5. The lowered portion 375 is provided on the edges of two faces that face each other among the multiple faces that constitute the first block portion. The lowered portion 375 is a portion in which the edges of each of the two faces are locally lowered. The partial core piece 370 is manufactured by pressure molding a raw material powder containing soft magnetic powder. The direction of pressure molding of the raw material powder is the direction in which the two faces of the resulting partial core piece 370 face each other. During this pressure molding, the lowered portion 375 is formed on the edges of each of the two faces. The two faces correspond to the first face 111 and the second face 112 of the first part 11 described above.

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

[0076] In the third step, composite material is filled into each of the second spaces 321, 322, and 323 so as to overlap the lower stepped portion 375 of the partial core piece 370. The composite material filled into each of the second spaces 321, 322, and 323 covers the end face of the partial core piece 370 and also covers the lower stepped portion 375. The composite material filled into each of the second spaces 321, 322, and 323 solidifies while shrinking. The partial core piece 370 becomes the first part 11, and the composite material filled into each of the second spaces 321, 322, and 323 solidifies to become the second part 12. The solidified composite material that overlaps the lower stepped portion 375 becomes the protrusions 125 and 126 (Figure 2). In this example, the extended portion 127 (Figure 2) is also formed from the composite material that solidifies to overlap the lower stepped portion 375. Since the lower section 375 is provided on two sides of the first block section of the partial core piece 370, the protrusions 125 and 126, which are formed by solidification overlapping the lower section 375, sandwich the partial core piece 370 at the lower section 375.

[0077] In the third step, at least two of the multiple second spaces 321, 322, and 323 can be filled with different composite materials. For example, the same composite material may be filled into the second space 322 and the second space 323, and a different composite material may be filled into the second space 321 than into the second spaces 322 and 323. Alternatively, different composite materials may be filled into the second spaces 321, 322, and 323. In this example, since a gate 350 is provided for each of the second spaces 321, 322, and 323, different composite materials can be filled into the second spaces 321, 322, and 323.

[0078] In the core piece 1 obtained by the core piece manufacturing method described above, gate marks are formed in each of the second parts 12A, 12B, and 12C. In other words, the core piece 1 has three gate marks.

[0079] Reactor The reactor 7 of Embodiment 1 will be described with reference to Figures 5 and 6. The reactor 7 comprises a magnetic core 8 and a coil 9. The magnetic core 8 is composed of a set of a first core piece 81 and a second core piece 82. The coil 9 is located in a part of the magnetic core 8. One of the features of the reactor 7 of Embodiment 1 is that at least one of the first core piece 81 and the second core piece 82 is the core piece 1 described above. In this example, the first core piece 81 is the core piece 1 described above.

[0080] [Magnetic core] The magnetic core 8 is a magnetic element that forms an annular magnetic path by exciting the coil 9. In this example, the magnetic core 8 is configured in a θ shape as a whole by combining a first core piece 81 and a second core piece 82. Below, the overall shape of the magnetic core 8 will be described first, followed by a description of the combination of the first core piece 81 and the second core piece 82.

[0081] <Overall shape of the magnetic core> The magnetic core 8 comprises a middle core portion 2, two side core portions 3 and 4, and two end core portions 5 and 6. In Figure 6, a dashed line is drawn at the boundary between the middle core portion 2 and each end core portion 5 and 6. In Figure 6, cross-hatching is applied to the portion of the magnetic core 8 that is made up of a compacted soft magnetic powder.

[0082] The middle core portion 2 has a portion that is located inside the winding portion 90 (Figures 5 and 6) of the coil 9, which will be described later. In this example, the middle core portion 2 is composed of 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 the same cross-sectional area as the middle core portion 21 of the first core piece 81. The lengths of the middle core portions 21 and 22 along the second direction D2 are the same. The lengths of the middle core portions 21 and 22 along the third direction D3 are the same. 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 easier to adjust the inductance of the reactor 7. For example, a gap material (not shown) is placed in the gap. Known materials can be used as the gap material. The constituent material of the gap material is, for example, non-magnetic ceramics or resin. The gap may be an air gap in which no gap material is placed. If the reactor 7 includes a molded resin portion 10, which will be described later, the gap may be filled with the resin that makes up the molded resin portion 10. In this case, the resin that makes up the molded resin portion 10 becomes the gap material.

[0083] The length of the middle core portion 2 along the first direction D1 is equal to or greater than the length of the winding portion 90 of the coil 9 (Figures 5 and 6), which will be described later, along the first direction D1. In this example, the length of the middle core portion 2 along the first direction D1 is slightly longer than the length of the winding portion 90 along the first direction D1. In other words, the middle core portion 2 comprises a portion located inside the winding portion 90 and a portion located 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 and 4 are the side core portions 3 and 4 of the first core piece 81, that is, the core piece 1 described above.

[0085] One of the two end core portions 5 and 6, end core portion 5, is the end core portion 5 of the first core piece 81, that is, the core piece 1 described above. One of the two end core portions 5 and 6, 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 core piece 1.

[0086] The magnetic core 8 is formed when the coil 9, described later, is energized by the connection of the middle core section 2, the two side core sections 3 and 4, and the two end core sections 5 and 6. This allows magnetic flux to flow and a closed magnetic path to be formed. As shown by the dashed arrows in Figure 7, the magnetic flux flows from the middle core section 2 to the end core section 5, from the end core section 5 to each of the two side core sections 3 and 4, from each side core section 3 and 4 to the end core section 6, and from the end core section 6 to the middle core section 2.

[0087] <combination> The first core piece 81 and the second core piece 82 are divided pieces that separate the magnetic core 8 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. When the E-shaped first core piece 81 and the T-shaped second core piece 82 are combined, the magnetic core 8 has a θ-shape.

[0088] The first core piece 81 in this example is the core piece 1 described above, and comprises a first portion 11 and a second portion 12.

[0089] The second core piece 82 in this example is made of a compacted powder molded body. In other words, the second core piece 82 in this example comprises only the first portion 11. The second core piece 82 may consist of the first portion 11, or it may consist of a composite of the first portion 11 and the second portion 12. When the second core piece 82 consists of a composite of the first portion 11 and the second portion 12, the first portion 11 comprises the end core portion 5, and the second portion 12 comprises the middle core portion 22. The first portion 11 and the second portion 12 are joined together at their end faces 113, 123A, 123B, and 123C, as well as at their lower stepped portions 115, 116 and protrusions 125, 126, similar to the core piece 1 described above.

[0090] The shape of the second core piece 82 is not particularly limited. The shape of the second core piece 82 may be, for example, E-shaped. An E-shaped second core piece 82 comprises 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 can be adjusted as appropriate.

[0091] 〔coil〕 The coil 9 comprises at least one winding section 90. The coil 9 in this example comprises one winding section 90. The winding section 90 is constructed by winding a single wire spirally. Both ends of the wire are drawn out from each end of the winding section 90. Terminal fittings (not shown) are attached to both ends of the wire drawn out from the winding section 90. External devices (not shown) are connected to the terminal fittings. In Figures 5 and 6, only the winding section 90 is shown, and the ends of the wire are omitted.

[0092] Known windings can be used for the winding. In this example, the winding is a coated flat wire consisting of a conductor wire with an insulating coating. The conductor wire is made of, for example, a copper flat wire. The insulating coating is made of, for example, enamel. The winding section 90 in this example is an edgewise coil formed by winding the coated flat wire edgewise.

[0093] The winding portion 90 has a rectangular tubular shape. That is, the end face 91 of the winding portion 90 in this example has a rectangular frame shape. The winding portion 90 has an inner surface 92 and an outer surface 93. The inner surface 92 faces the middle core portion 2. There is a gap between the inner surface 92 and the outer surface of the middle core portion 2. If the reactor 7 has a molded resin portion 10, which will be described later, this gap is filled with the resin that makes up the molded resin portion 10. The outer 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 rectangular tubular shape, the contact area between the winding portion 90 and the object to be installed tends to be larger compared to when the winding portion is cylindrical with the same cross-sectional area. A larger contact area between the winding portion 90 and the object to be installed improves the heat dissipation of the reactor 7. A larger contact area between the winding section 90 and the object to be installed makes it easier to stabilize the installation of the winding section 90 on the object.

[0094] [Molded resin part] The reactor 7 may include a molded resin portion 10, as shown in Figure 5. In Figure 5, the appearance of the molded resin portion 10 is shown by a dashed line for clarity. The molded resin portion 10 covers at least a part of the magnetic core 8. The molded resin portion 10 has the function of protecting the magnetic core 8 from the external environment. The molded resin portion 10 may further cover the coil 9. In other words, the molded resin portion 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 portion 10 integrates the magnetic core 8 and the coil 9 into a single unit. 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 portion 10.

[0095] If the molded resin portion 10 is provided between the magnetic core 8 and the coil 9, insulation between the magnetic core 8 and the coil 9 is easily ensured. If the molded resin portion 10 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, the molded resin portion 10 provided between them 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 composite material described above. The constituent material of the molded resin portion 10 may also contain the filler described above, similar to the composite material.

[0097] 〔others〕 The reactor 7 may include a retaining member, although not shown in the figures. The retaining member is positioned between the magnetic core 8 and the coil 9 and has the function of ensuring electrical insulation between the magnetic core 8 and the coil 9. The retaining member defines the relative positions of the magnetic core 8 and the coil 9 and has the function of maintaining the positioning state. The retaining member is positioned, for example, between the end face 91 of the winding portion 90 and the end core portions 5 and 6. The retaining member positioned 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 retaining member is positioned, for example, between the inner circumferential surface of the winding portion 90 and the outer circumferential surface of the middle core portion 2. The retaining member positioned between the inner circumferential surface of the winding portion 90 and the outer circumferential surface of the middle core portion 2 is, for example, a cylindrical member. The retaining member positioned between the inner circumferential surface of the winding portion 90 and the outer circumferential surface of the middle core portion 2 has a structure that allows the unsolidified constituent resin of the molded resin portion 10 to flow between the winding portion 90 and the middle core portion 2.

[0098] <Embodiment 2> ≪Core Piece≫ The core piece 1 of Embodiment 2 will be described with reference to Figures 7 and 8. Similar to the core piece 1 of Embodiment 1, the core piece 1 of Embodiment 2 is a single piece formed by integrally molding a first portion 11 and a plurality of second portions 12, with the first portion 11 and the plurality of second portions 12, which are made of different materials, being well joined together. One of the features of the core piece 1 of Embodiment 2 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 Embodiment 2 is the same as that of the core piece 1 of Embodiment 1. The differences from the core piece 1 of Embodiment 1 will be described below.

[0099] [First part] The first block portion 110 of the first part 11 is a block body having a portion that is positioned to face the end face 91 (Figure 6) of the winding portion 90 of the coil 9. The first block portion 110 in this example includes a part of the end core portion 5. The first block portion 110 has an I-shape formed from a part of the end core portion 5. The length of the first block portion 110 in 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 part 11 in this example is positioned biased toward the third direction D3 of the end core portion 5.

[0100] The first surface 111 of the first block section 110 is provided with a stepped section 115. The stepped section 115 is provided on the edge of the first surface 111. The stepped section 115 is a portion of the edge of the first surface 111 that is locally lowered. In this example, the stepped section 115 is provided continuously around the entire circumference of the first surface 111.

[0101] Although not shown in the figures, the second surface of the first block section 110 is provided with a stepped section. The second surface of the first block section 110 is the surface facing the first surface 111 shown in Figure 8. The stepped section is provided at the edge of the second surface. The stepped section is a portion where the edge of the second surface is locally lowered. In this example, the stepped section is provided continuously around the entire circumference of the second surface, similar to the stepped section 115 shown in Figure 8.

[0102] [Second part] The core piece 1 of Embodiment 2, like the core piece 1 of Embodiment 1, comprises three second parts 12A, 12B, and 12C.

[0103] The second block portion 120A of the second part 12A includes a middle core portion 21. The second block portion 120A has an I-shaped form composed of the middle core portion 21. Multiple surfaces constituting the second block portion 120A have end faces 123A facing the first part 11.

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

[0105] The second block portion 120C of the second part 12C includes a side core portion 4. The second block portion 120C has an I-shaped form composed of the side core portion 4. of The multiple surfaces that make up the block also have end faces 123C that face the first portion 11, similar to the second block portion 120A.

[0106] The second block sections 120A, 120B, and 120C are block bodies arranged to face the inner surface 92 (Figure 6) of the winding section 90 of the coil 9, which will be described later.

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

[0108] In this example, the projection 125 is a connecting projection 128 that is connected to all of the second sections 12A, 12B, and 12C. The connecting projection 128 is provided on the first surface 111 of the first block section 110 so as to continuously overlap both the lower step section 115 and the area other than the lower step section 115. The connecting projection 128 constitutes a part of the end core section 5. The end core section 5 is composed of the part of the first block section 110 described above and the connecting projection 128. In other words, the end core section 5 is composed of the first section 11 and a part of the second section 12. In Figure 7, dashed lines are drawn at the boundary between the middle core section 21 and the end core section 5, and at the boundary between the side core sections 3, 4 and the end core section 5. At both ends of the connecting projection 128 in the second direction D2, there are extensions 127 composed of projections that extend along the first direction D1.

[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 portion 116. The protrusions 126 have the same configuration as the protrusions 126 described in Embodiment 1.

[0110] As shown in Figure 9, the reactor 7 of Embodiment 2 includes a first core piece 81 composed of the core piece 1 of Embodiment 2 described above. The configuration of the second core piece 82 and the coil 9 are the same as in Embodiment 1. In this example, a portion of the second part 12 is positioned to face the end face 91 of the coil 9. By positioning a portion of the second part 12 to face the end face 91 of the coil 9, the magnetic properties are improved even at high currents.

[0111] <Variation> Although not shown, the coil may have two winding sections. In this case, the magnetic core comprises two inner core sections and two outer core sections. The two inner core sections are provided so as to face the inner surfaces of the winding sections. The two outer core sections are provided so as to connect the end faces of the two inner core sections. The two outer core sections have portions provided so as to face the end faces of each winding section. The core pieces constituting the magnetic core are, for example, made up of U-shaped blocks. The U-shaped core piece is made up of a first section and a second section joined together. For example, the first section is made up of one outer core section and a part of each of the two inner core sections. The second section is made up of the remainder of the two inner core sections. The first section has a lower section, and the second section has a protruding section.

[0112] <Embodiment 3> <<Converters / Power Conversion Devices>> The reactor 7 of Embodiment 1 or Embodiment 2 described above can be used for applications that satisfy the following energizing conditions. For example, the energizing conditions are that the maximum DC current is approximately 100A to 1000A, the average voltage is approximately 100V to 1000V, and the operating frequency is approximately 5kHz to 100kHz. 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 equipped with such a converter.

[0113] A vehicle 1200, such as a hybrid or electric vehicle, includes a main battery 1210, a power converter 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 propulsion, as shown in Figure 10. The motor 1220 is typically a three-phase AC motor, which drives the wheels 1250 during driving and functions as a generator during regenerative braking. In the case of a hybrid vehicle, the vehicle 1200 is equipped with an engine 1300 in addition to the motor 1220. In Figure 10, the charging point of the vehicle 1200 is an inlet, but it may also be equipped with a plug.

[0114] The power converter 1100 includes a converter 1110 connected to the main battery 1210 and an inverter 1120 connected to the converter 1110 that performs mutual conversion between DC and AC. In this example, the converter 1110 boosts the input voltage of the main battery 1210, which is approximately 200V to 300V, to approximately 400V to 700V when the vehicle 1200 is running, and supplies power to the inverter 1120. During regeneration, the converter 1110 steps down the input voltage output from the motor 1220 via the inverter 1120 to a DC voltage suitable for the main battery 1210, thereby charging the main battery 1210. The input voltage is a DC voltage. When the vehicle 1200 is running, the inverter 1120 converts the DC voltage boosted by the converter 1110 into a predetermined AC voltage and supplies power to the motor 1220. During regeneration, it converts the AC output from the motor 1220 into DC voltage and outputs it to the converter 1110.

[0115] As shown in Figure 11, the converter 1110 comprises a plurality of switching elements 1111, a drive circuit 1112 that controls the operation of the switching elements 1111, and a reactor 1115, and converts the input voltage by repeatedly switching ON / OFF. In this case, the input voltage conversion is step-up or step-down. Power devices such as field-effect transistors and insulated-gate bipolar transistors are used as switching elements 1111. The reactor 1115 utilizes the property of a coil that tries to oppose changes in the current that is about to flow through the circuit, and has the function of smoothing the change when the current tries to increase or decrease due to the switching operation. The reactor 1115 is provided as the reactor 7 of Embodiment 1 or Embodiment 2.

[0116] Vehicle 1200 includes, in addition to converter 1110, a power supply device converter 1150 connected to the main battery 1210, and an auxiliary power converter 1160 connected to the main battery 1210 and a sub-battery 1230 which serves as a power source for auxiliary equipment 1240, and which converts the high voltage of the main battery 1210 to low voltage. Converter 1110 typically performs DC-DC conversion, while power supply device converter 1150 and auxiliary power converter 1160 perform AC-DC conversion. Some power supply device converters 1150 also perform DC-DC conversion. The reactors of the power supply device converter 1150 and auxiliary power converter 1160 have the same configuration as the reactor 7 of Embodiment 1 or Embodiment 2, and reactors with appropriately changed size and shape can be used. Furthermore, the reactor 7 of Embodiment 1 or Embodiment 2 can also be used for converters that perform input power conversion, such as converters that only perform boosting or converters that only perform 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 section 12,12A,12B,12C Second part 120A, 120B, 120C Second Block Section 123A,123B,123C end face 125,126 Protrusions 127 Extension section 128 Connecting protrusion 2,21,22 Middle Core Section 3,4 Side core section 5,6 End core section 7 Reactor 8 magnetic cores 81 First core piece 82 Second core piece 9 coils 90-volume section 91 End face 92 Inner surface 93 External surface 10. Mold resin part 300 molds 310 The first space 321,322,323 Second Space 330 Sprue 340 runners 350 gates 370 partial core pieces 375 Lower section D1 first direction, D2 second direction, D3 third direction 1100 Power converter, 1110 Converter, 1111 Switching element 1112 Drive circuit, 1115 Reactor, 1120 Inverter 1150 Converter for power supply equipment, 1160 Converter for auxiliary power supply equipment 1200 vehicles, 1210 main batteries, 1220 motors 1230 Sub-battery, 1240 Auxiliary equipment, 1250 Wheels, 1300 Engine

Claims

1. A core piece for forming a magnetic core that is placed inside and outside a coil, The first part is composed of a compacted molded body of soft magnetic powder, It comprises a plurality of second parts, each composed of a molded body of a composite material in which soft magnetic powder is dispersed in a resin, The aforementioned first part is, A first block portion having a portion that faces the end face of the coil, The first block portion comprises a lowered section in which the edges of two faces facing each other among the multiple faces constituting the first block portion are locally lowered, Each of the aforementioned multiple second parts is A second block portion having a side surface facing either the inner or outer surface of the coil, and arranged to face the side surface of an adjacent second portion, The second block portion comprises a projection provided on the edge of the end face that constitutes the second block portion so as to overlap with the lower step portion. Core piece.

2. The aforementioned multiple second parts are configured independently of each other, The core piece according to claim 1, wherein the first portion comprises the lower step portion corresponding to each of the protrusions of the plurality of second portions.

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

4. The core piece according to claim 1 or claim 2, wherein the plurality of second parts include a molded body composed of different composite materials.

5. The projection includes connecting projections that are connected to all of the plurality of second parts. The core piece according to claim 1, wherein the connecting projection is provided on one of two faces of the plurality of faces constituting the first block portion, so as to continuously overlap both the lower step portion and the portion other than the lower step portion.

6. A magnetic core is composed of a set of a first core piece and a second core piece, The magnetic core comprises a coil disposed in part of the magnetic core, At least one of the first core piece and the second core piece is the core piece described in claim 1 or claim 2. Reactor.

7. The reactor comprises the reactor described in claim 6, converter.

8. A converter comprising the converter described in claim 7, Power converter.

9. A step of preparing a mold having a first space and a plurality of second spaces that communicate with each other, A step of placing a partial core piece, which is made of a compacted molded body of soft magnetic powder, into a space including the first space, The process includes a step of 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 aforementioned second spaces extends in a direction intersecting the first space and is arranged side by side with the others. The aforementioned partial core piece is The first block section, The first block portion comprises a lowered section in which the edges of two faces facing each other among the multiple faces constituting 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. A method for manufacturing core pieces.

10. The method for manufacturing a core piece according to claim 9, wherein the filling step involves filling at least two of the plurality of second spaces with different composite materials.

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