Reactor, converter, power conversion device, and method for manufacturing reactor

Abstract

This reactor comprises a coil and a magnetic core. The magnetic core comprises two end core portions and a middle core portion. Each of the two end core portions and the middle core portion comprises a first part and a second part. The first part is formed of a powder compact of soft magnetic powder. The second part is formed of a molded body of a composite material in which soft magnetic powder is dispersed in a resin. The first part of each of the two end core portions forms a part of an outer end surface of the end core portion and extends in a first direction along the axis of the coil. The first part of the middle core portion has a portion that is provided integrally with the first part of each of the two end core portions and is disposed inside the coil. The second part of each of the two end core portions is disposed so as to cover an entire peripheral surface of the first part excluding the outer end surface thereof.

Description

Reactor, Converter, Power Conversion Device, and Method for Manufacturing Reactor

[0001] The present disclosure relates to a reactor, a converter, a power conversion device, and a method for manufacturing a reactor. This application claims priority based on Japanese Patent Application No. 2025-018586 filed on February 6, 2025, and incorporates by reference all the descriptions described in the above Japanese application.

[0002] The magnetic core of the reactor of Patent Document 1 includes a core piece formed by combining a first core piece and a second core piece. The first core piece is formed of a molded body of a composite material in which soft magnetic powder is dispersed in resin. The second core piece is formed of a compacted molded body 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 portion formed of the above compacted molded body is referred to as the first portion, and the portion formed of the molded body of the above composite material is referred to as the second portion.

[0003] Japanese Unexamined Patent Application Publication No. 2022-45166

[0004] The reactor of this disclosure comprises a coil and a magnetic core. The magnetic core comprises two end core portions and a middle core portion. The two end core portions extend in a direction intersecting the axis of the coil so as to sandwich the coil. Each of the two end core portions comprises an inner end face and an outer end face. The inner end face faces the coil. The outer end face is the back surface of the inner end face. The middle core portion has a portion disposed inside the coil and extends in a first direction along the axis of the coil so as to connect to the inner end faces of the two end core portions. Each of the two end core portions and the middle core portion comprises a first portion and a second portion. The first portion is formed of a compacted molded body of soft magnetic powder. The second portion is formed of a molded body of a composite material in which soft magnetic powder is dispersed in a resin. The first portion of each of the two end core portions forms a part of the outer end face and extends in the first direction. The first portion of the middle core portion has a portion provided integrally with the first portion of each of the two end core portions and disposed inside the coil. The second portion of each of the two end core portions is arranged to cover the entire circumferential surface of the first portion, excluding the outer end surface.

[0005] Figure 1 is a schematic perspective view showing a reactor of an embodiment. Figure 2 is a schematic perspective view showing the reactor of Figure 1 with the magnetic core and separator combined. Figure 3 is a schematic perspective view showing the magnetic core of the reactor of Figure 1. Figure 4 is a schematic perspective view showing the reactor of Figure 1 with the first portion of the second end core and the first portion of the middle core assembled to the separator. Figure 5 is a schematic end view of the first end core portion of the reactor of Figure 1 as seen from a first direction. Figure 6 is a schematic cross-sectional view illustrating the manufacturing method of the reactor of the embodiment. Figure 7 is a schematic configuration diagram showing the power supply system of a hybrid vehicle. Figure 8 is a circuit diagram showing an example of a power conversion device equipped with a converter.

[0006] In a magnetic core comprising a first and second portion made of different materials, it is desirable that the first and second portions be well joined together. The first portion, formed from a compacted powder, has lower strength than the second portion, formed from a composite material. In a magnetic core, if the end core portion, which extends in a direction intersecting the coil axis so as to sandwich the coil, is formed from the first and second portions, it is desirable that the first and second portions be firmly joined to each other with a sufficient contact area.

[0007] In Patent Document 1, during the manufacturing process of the core piece, the powder compact formed as the first part is held within the mold so that it does not shift due to the flow of the composite material. The surface of the powder compact held within the mold is not covered with the composite material.

[0008] One of the purposes of this disclosure is to provide a reactor having a magnetic core in which a first portion and a second portion made of different materials are well joined together. Another purpose of this disclosure is to provide a converter having the reactor described above. Another purpose of this disclosure is to provide a power conversion device having the converter described above. Another purpose of this disclosure is to provide a method for manufacturing a reactor having a magnetic core in which a first portion and a second portion made of different materials are well joined together.

[0009] The magnetic core of the reactor of this disclosure has a first portion and a second portion made of different materials that are well joined together, and there is a high degree of freedom in selecting the relative positions of the first portion and the second portion.

[0010] First, the embodiments of this disclosure will be listed and described.

[0011] (1) A reactor according to the embodiment of the present disclosure comprises a coil and a magnetic core. The magnetic core comprises two end core portions and a middle core portion. The two end core portions extend in a direction intersecting the axis of the coil so as to sandwich the coil. Each of the two end core portions comprises an inner end face and an outer end face. The inner end face faces the coil. The outer end face is the back surface of the inner end face. The middle core portion has a portion located inside the coil and extends in a first direction along the axis of the coil so as to connect to the inner end faces of the two end core portions. Each of the two end core portions and the middle core portion comprises a first portion and a second portion. The first portion is formed of a compacted molded body of soft magnetic powder. The second portion is formed of a molded body of a composite material in which soft magnetic powder is dispersed in a resin. The first portion of each of the two end core portions forms a part of the outer end face and extends in the first direction. The first portion of the middle core has a portion that is provided integrally with the first portion of each of the two end cores and is positioned inside the coil. The second portion of each of the two end cores is positioned to cover the entire circumferential surface of the first portion, excluding the outer end surface.

[0012] Powder compacts allow for a higher proportion of soft magnetic powder in the molded body compared to molded bodies made of composite materials. Powder compacts with a high proportion of soft magnetic powder 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. Although molded bodies made of composite materials have lower permeability compared to powder compacts, they are less prone to magnetic saturation under high-current operating conditions and have low iron loss. Therefore, a magnetic core comprising a first part formed from a powder compact and a second part formed from a composite material exhibits excellent magnetic properties even under high currents.

[0013] In the end core section, the entire circumferential surface of the first section is covered by the second section, so the first and second sections are joined well to each other with a sufficient contact area. Although the first section, formed from a compacted powder molded body, has lower strength than the second section, formed from a composite material molded body, it is less prone to breakage because its entire circumferential surface, excluding the outer end face, is covered by the second section. If the entire circumferential surface of the first section, excluding the outer end face, can be covered by the second section in each end core section, the relative positions of the first and second sections can be selected more freely.

[0014] (2) In the reactor described in (1) above, the number of first parts of the middle core is two, and the second part of the middle core may be located between the two first parts of the middle core.

[0015] When there are two first parts in the middle core, the first parts of the middle core are located at the first and second ends of the middle core. When the second part is located in the central region between the first and second ends of the middle core, it is easier to lower the permeability of the magnetic core compared to when the first part is located throughout the entire middle core. Lower permeability of the magnetic core makes it easier to reduce the gap in the magnetic core. Reducing the gap makes it easier to reduce leakage flux from the gap.

[0016] (3) In the reactor described in (1) or (2) above, the second portion of each of the two end core portions forms a part of the outer end surface, and the outer end surface of the first portion and the outer end surface of the second portion may be flush.

[0017] In each end core section, if the outer end surface of the first section and the outer end surface of the second section are flush, magnetic flux flows easily from the first section to the second section or from the second section to the first section. In each end core section, if the outer end surface of the first section and the outer end surface of the second section are flush, it is easier to make the outer end surface of the end core section a smooth surface without irregularities.

[0018] (4) The reactor described in any of (1) to (3) above may further comprise a spacer. The spacer comprises a main body, a through hole, and a positioning portion. The main body is positioned between the end face of the coil and the end core portion. The through hole is provided in the main body so as to allow the first portion of the middle core portion to pass through. The positioning portion is provided on the inner circumferential surface of the through hole so as to position the first portion of the middle core portion relative to the main body by contacting a part of the first portion of the middle core portion.

[0019] The first portion of the end core and the first portion of the middle core are integrally molded. The first portion of the middle core is positioned by a spacer, which facilitates the relative positioning of the middle core and the end core. The spacer also facilitates the positioning of the coil and the magnetic core.

[0020] (5) In the reactor described in any of (1) to (4) above, the number of coils is one, and the magnetic core may include a side core portion. The side core portion extends in the first direction outside the coil so as to connect to the inner end faces of the two end core portions.

[0021] When there is only one coil, the magnetic core comprises two end core sections, one middle core section, and one or more side core sections, so that an annular magnetic path is formed in the magnetic core by the excitation of the coil.

[0022] (6) The reactor described in (5) above further comprises a spacer, the spacer may have a side portion disposed between the coil and the side core portion.

[0023] The spacer provides insulation between the coil and the side core.

[0024] (7) In the reactor described in any of (1) to (6) above, each of the two end core portions may have a rectangular envelope shape with a long side and a short side when viewed from the first direction.

[0025] The end core portion having the above-described envelope shape facilitates the construction of a flat, thin reactor.

[0026] (8) In the reactor described in any of (1) to (7) above, the second portion of each of the two end core portions and the middle core portion may be a single molded product.

[0027] If the second portion of each end core and the second portion of the middle core are integrally molded, the two end cores and the middle core can be joined together more easily.

[0028] (9) A converter according to an embodiment of the present disclosure comprises a reactor as described in any of (1) to (8) above.

[0029] Converters equipped with the above-mentioned reactor exhibit excellent magnetic properties.

[0030] (10) A power conversion device according to the embodiment of the present disclosure comprises the converter described in (9) above.

[0031] A power conversion device equipped with the above converter exhibits excellent magnetic properties.

[0032] (11) A method for manufacturing a reactor according to an embodiment of the present disclosure comprises a first step of arranging an assembly of a coil and a columnar core piece inside a mold, and a second step of filling the inside of the mold in which the assembly is arranged with a composite material. The core piece is formed of a compacted molded body of soft magnetic powder. The composite material has soft magnetic powder dispersed in a resin. The mold is provided with magnets at locations facing at least one of the end faces of both end faces of the core piece. In the first step, a part of the core piece is placed inside the coil. In the second step, with the end face of the core piece attracted to the magnet, the entire circumferential surface of the core piece that is located outside the coil is covered with the composite material.

[0033] In the above reactor manufacturing method, when a composite material is filled into a mold in which an assembly of a coil and a core piece is placed, the entire circumferential surface of the core piece, excluding the end face attracted to the magnet, is covered with the composite material. The composite material filled into the mold solidifies while shrinking. The core piece becomes the first part, and the composite material filled into the mold solidifies to become the second part. In the above reactor manufacturing method, since the end face of the core piece is attracted to the magnet, the core piece does not move even when subjected to the flow of the composite material. In the above reactor manufacturing method, as the composite material covering the entire circumferential surface of the core piece, excluding the end face attracted to the magnet, solidifies, a magnetic core can be manufactured in which the first part and the second part, made of different materials, are well joined to each other with a sufficient contact area.

[0034] 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 components. The present invention is not limited to these examples, but is indicated by the claims, and all modifications within the meaning and scope of the claims are intended to be included. It should be understood that at least one configuration or feature described in each embodiment and example can be combined with other embodiments and examples, or modified in various ways.

[0035] <Reactor> The reactor 1 of the embodiment will be described with reference to Figures 1 to 5.

[0036] ≪Overview≫ As shown in Figure 1, the reactor 1 comprises a coil 2 and a magnetic core 3. As shown in Figure 3, the magnetic core 3 comprises two end core portions, a first end core portion 4 and a second end core portion 5, and a middle core portion 6. In this example, the magnetic core 3 comprises one middle core portion 6 and one side core portion 7. The first end core portion 4 and the second end core portion 5 extend in a direction intersecting the axis of the coil 2 so as to sandwich the coil 2. The middle core portion 6 extends in a direction along the axis of the coil 2 so as to connect to the inner end face 4A of the first end core portion 4 and the inner end face 5A of the second end core portion 5. The middle core portion 6 has a portion located inside the coil 2. The side core portion 7 extends in a direction along the axis of the coil 2 so as to connect to the inner end face 4A of the first end core portion 4 and the inner end face 5A of the second end core portion 5 outside the coil 2. The middle core portion 6 and the side core portion 7 are arranged side by side in a direction intersecting the axis of the coil 2.

[0037] The first end core portion 4 comprises a first portion 41 and a second portion 42. The second end core portion 5 comprises a first portion 51 and a second portion 52. The middle core portion 6 comprises a first portion 61 and a second portion 62. The first portions 41, 51, and 61 are formed from compacted molded bodies of soft magnetic powder. The second portions 42, 52, and 62 are formed from molded bodies of composite material in which soft magnetic powder is dispersed in resin. One of the features of the reactor 1 of this embodiment is that in the first end core portion 4, the second portion 42 is arranged to cover the entire circumference of the circumferential surface 415 (Figure 5) of the first portion 41. Another feature of the reactor 1 of this embodiment is that in the second end core portion 5, the second portion 52 is arranged to cover the entire circumference of the circumferential surface 515 (Figure 4) of the first portion 51. Cross-hatching is applied to the first portions 41, 51, and 61 in each figure for clarity.

[0038] In this example, the reactor 1 includes a spacer 8. The spacer 8 is positioned to insulate the coil 2 from the magnetic core 3.

[0039] In this specification, the first direction D1, the second direction D2, and the third direction D3 may be used for explanation. The first direction D1 is the direction along the axis of the coil 2. The first direction D1 is also the direction in which the middle core portion 6 and the side core portion 7 extend. The second direction D2 is the direction in which the middle core portion 6 and the side core portion 7 are aligned. The third direction D3 is the direction perpendicular to both the first direction D1 and the second direction D2. 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. In this specification, 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.

[0040] <Coil> Coil 2 is formed by windings, as shown in Figure 1. Coil 2 comprises a winding section 20 and winding ends 21 and 22. In this example, there is one coil 2. In this example, there is also one winding section 20. The axis of coil 2 is the axis of the winding section 20.

[0041] The winding section 20 is formed by winding the wire in a helical shape. In this example, the winding section 20 is formed in a flat cylindrical shape. In this example, the winding section 20 has an envelope shape with a long side and a short side when viewed from the first direction D1. The envelope shape is the smallest rectangular shape that surrounds the winding section 20 when viewed from the first direction D1. The long side is the side of the envelope shape along the second direction D2, and the short side is the side of the envelope shape along the third direction D3. The surfaces of the winding section 20 that face each other in the third direction D3 have flat surfaces. If at least one of the surfaces of the winding section 20 that face each other in the third direction D3 is used as the mounting surface for the mounting object, the contact area between the coil 2 and the mounting object can be easily increased. The mounting object is, for example, a case in which a refrigerant is circulated. The larger the contact area between the coil 2 and the mounting object, the more efficiently the reactor 1 can dissipate heat.

[0042] The winding wire forming the winding part 20 can be a known winding wire. The winding wire in this example is a covered rectangular wire. The conductor wire of the covered rectangular wire is formed of, for example, a rectangular wire made of copper. The insulating coating of the covered rectangular wire is made of, for example, enamel. In this example, the winding part 20 is formed by edgewise winding of the covered rectangular wire. The winding part 20 may be formed by flatwise winding of the covered rectangular wire.

[0043] The winding wire end 21 is drawn out from the first end of the winding part 20. The winding wire end 22 is drawn out from the second end of the winding part 20. The winding wire ends 21 and 22 in this example are drawn out along the second direction D2. The insulating coatings of the winding wire ends 21 and 22 are peeled off to expose the conductor wires. Terminals (not shown) are connected to the exposed conductor wires of the winding wire ends 21 and 22. An external device (not shown) is connected to the terminals. The external device is, for example, a power source that supplies power to the coil 2.

[0044] The number of coils 2 may be plural. In this case, the number of winding parts 20 is plural. The plural winding parts 20 are arranged side by side so that their axes are parallel to each other. When the plural winding parts 20 are arranged side by side, the middle core parts 6 are respectively arranged inside each winding part 20. That is, when the plural winding parts 20 are arranged side by side, the magnetic core 3 includes the first end core part 4, the second end core part 5, and the plural middle core parts 6. The magnetic core 3 is annular. The winding wires forming each winding part 20 may be independent of each other or may be formed in series. When the winding wires forming each winding part 20 are independent of each other, the winding wires may be connected to each other by a member that electrically connects the winding wires.

[0045] ≪Magnetic Core≫ The magnetic core 3 is a magnetic member for forming an annular magnetic path by excitation of the coil 2. The magnetic core 3 in this example has an O-shaped configuration formed by the first end core part 4, the second end core part 5, the middle core part 6, and the side core part 7 as shown in FIG. 3. In FIGS. 2 and 3, for easy understanding, a two-dot chain line is attached to the boundary between the first end core part 4 and the side core part 7 and the boundary between the second end core part 5 and the side core part 7.

[0046] [First End Core Portion] As shown in FIG. 1, the first end core portion 4 is disposed to face the first end surface of the winding portion 20. The first end core portion 4 is a columnar body extending in the second direction D2. The first end core portion 4 has a shape connecting to the first end surfaces of the middle core portion 6 and the side core portion 7.

[0047] The first end core portion 4 in this example is a prismatic body that is longer in the second direction D2 than in the first direction D1 and the third direction D3. The prismatic body includes a prismatic body in which at least one of the corners forming the first end core portion 4 is rounded. As shown in FIG. 5, the first end core portion 4 in this example has a rectangular envelope shape 45 having a long side 45L and a short side 45S when viewed from the first direction D1. In FIG. 5, for clarity, the envelope shape 45 is indicated by a two-dot chain line slightly outside the outer shape of the first end core portion 4. The envelope shape 45 is the smallest rectangular shape surrounding the first end core portion 4 when the first end core portion 4 is viewed from the first direction D1. The side of the envelope shape 45 along the second direction D2 is the long side 45L, and the side of the envelope shape 45 along the third direction D3 is the short side 45S. The first end core portion 4 having the envelope shape 45 facilitates the construction of the flat and thin reactor 1.

[0048] The ratio of the long side 45L to the short side 45S in the envelope shape 45 is, for example, 2.5 or more. The above ratio is a ratio with the dimension of the short side 45S as the denominator and the dimension of the long side 45L as the numerator. The larger the value of the above ratio, the flatter and thinner the reactor 1 can be said. The above ratio may be 3.0 or more, or 4.0 or more. The upper limit of the above ratio may be appropriately set according to the required upper limit width of the reactor 1. The above ratio is, for example, 6.0 or less.

[0049] The first end core portion 4 includes an inner end surface 4A and an outer end surface 4B. The inner end surface 4A faces the first end surface of the coil 2. The first end surfaces of the middle core portion 6 and the side core portion 7 are connected to the inner end surface 4A. The outer end surface 4B is the back surface of the inner end surface 4A. The inner end surface 4A and the outer end surface 4B in this example are flat surfaces.

[0050] As shown in FIG. 3, the first end core portion 4 includes a first portion 41 and a second portion 42 made of different materials.

[0051] The first portion 41 is a columnar body extending in the first direction D1. The first portion 41 is integrally provided with the first portion 61 located at the first end 6A of the middle core portion 6, which will be described later. In other words, the first portion 41 of the first end core portion 4 and the first portion 61 located at the first end 6A are a single molded product. The first portion 41 of the first end core portion 4 and the first portion 61 located at the first end 6A are a single molded columnar powder compact. The single molded columnar powder compact is arranged across the first end core portion 4 and the middle core portion 6, with a part of the powder compact being the first portion 41 of the first end core portion 4 and the remainder being the first portion 61 of the middle core portion 6.

[0052] The first portion 41 is provided to form a part of the outer end surface 4B of the first end core portion 4. The first portion 41 includes an outer end surface 410 that forms a part of the outer end surface 4B of the first end core portion 4. In other words, the first portion 41 extends from the first portion 61 located at the first end 6A along the first direction D1 to the outer end surface 4B of the first end core portion 4. The first portion 41 is arranged along the entire length of the first end core portion 4 along the first direction D1.

[0053] The first portion 41 is located in a part of the intermediate region along the second direction D2 in the first end core portion 4. The first portion 41 is located in a part of the intermediate region along the third direction D3 in the first end core portion 4. The first portion 41 has an outer end surface 410 that forms a part of the outer end surface 4B of the first end core portion 4, but does not have a surface that forms any surface other than the outer end surface 4B of the first end core portion 4.

[0054] The second portion 42 is positioned to cover the entire circumference of the circumferential surface 415 (Figure 5) of the first portion 41, excluding the outer end surface 410. The entire circumference of the circumferential surface 415 of the first portion 41 is the joining surface with the second portion 42. Therefore, in the first end core portion 4, where the entire circumference of the circumferential surface 415 of the first portion 41 is covered by the second portion 42, the first portion 41 and the second portion 42 are well joined together. Although the first portion 41, formed from a compacted powder molded body, has lower strength than the second portion 42, which is formed from a composite material molded body, it is less prone to damage because the entire circumference of the circumferential surface 415, excluding the outer end surface 410, is covered by the second portion 42.

[0055] The second portion 42 forms the outer shape of the first end core portion 4. The second portion 42 comprises the inner end face 4A, the outer end face 4B, and most of the circumferential surface of the first end core portion 4. The second portion 42 includes an outer end face 420 that forms part of the outer end face 4B of the first end core portion 4. In this example, the outer end face 410 of the first portion 41 and the outer end face 420 of the second portion 42 are flush. When the outer end face 410 of the first portion 41 and the outer end face 420 of the second portion 42 are flush, magnetic flux flows easily from the first portion 41 to the second portion 42 or from the second portion 42 to the first portion 41. When the outer end face 410 of the first portion 41 and the outer end face 420 of the second portion 42 are flush, it is easier to make the outer end face 4B of the first end core portion 4 a smooth surface without irregularities.

[0056] In this example, the second portion 42 has a notch 4c on the side surface facing the second direction D2. The notch 4c opens to the inner end surface 4A, the outer end surface 4B, and the side surface. The second portion 42 in this example has a through hole 4h that penetrates the inner end surface 4A and the outer end surface 4B. The notch 4c and the through hole 4h are provided so as to sandwich the first portion 41 in the second direction D2. The notch 4c and the through hole 4h are traces left by pins (not shown) that fix the spacer 8, which will be described later, during the manufacturing process of the reactor 1.

[0057] In this example, the second part 42 is connected to the second part 62 of the middle core part 6, which will be described later. In other words, the second part 42 of the first end core part 4 and the second part 62 of the middle core part 6 are integrally molded. The second part 42 of the first end core part 4 and the second part 62 of the middle core part 6 are integrally molded composite material molded bodies. The integrally molded composite material molded body is arranged across the first end core part 4 and the middle core part 6, with a part of the composite material molded body being the second part 42 of the first end core part 4 and the remainder being the second part 62 of the middle core part 6. When the second part 42 of the first end core part 4 and the second part 62 of the middle core part 6 are integrally molded, the first end core part 4 and the middle core part 6 are easily joined together.

[0058] [Second End Core Section] As shown in Figure 1, the second end core section 5 is positioned facing the second end face of the winding section 20. The configuration of the second end core section 5 is the same as that of the first end core section 4. The description of the first end core section 4 can be explained by replacing the first end core section 4, inner end face 4A, outer end face 4B, first section 41, outer end face 410, circumferential surface 415, second section 42, outer end face 420, notch 4c, and through hole 4h with the second end core section 5, inner end face 5A, outer end face 5B, first section 51, outer end face 510, circumferential surface 515, second section 52, outer end face (not shown), notch 5c, and through hole 5h, respectively. However, the first section 51 is provided integrally with the first section 61 located at the second end 6B of the middle core section 6. In other words, the first portion 51 of the second end core portion 5 and the first portion 61 located at the second end 6B are integrally molded. The first portion 51 of the second end core portion 5 and the first portion 61 located at the second end 6B are integrally molded columnar compacted body. The integrally molded columnar compacted body is arranged across the second end core portion 5 and the middle core portion 6, with a part of the compacted body being the first portion 51 of the second end core portion 5 and the remainder being the first portion 61 of the middle core portion 6. In this example, the second end core portion 5 is symmetrical to the first end core portion 4. In this example, the axis of the first end core portion 4 and the axis of the second end core portion 5 are parallel.

[0059] [Middle Core Section] As shown in Figure 3, the middle core section 6 is arranged to connect to the inner end face 4A of the first end core section 4 and the inner end face 5A of the second end core section 5. The middle core section 6 is a columnar body extending in the first direction D1. In this example, the axis of the middle core section 6 is perpendicular to both the axis of the first end core section 4 and the axis of the second end core section 5. The middle core section 6 has a portion located inside the coil 2. The number of middle core sections 6 is the same as the number of winding sections 20. In this example, the number of middle core sections 6 is one, corresponding to the number of winding sections 20.

[0060] The shape of the middle core portion 6 can be appropriately selected from any shape. For example, the outer shape of the middle core portion 6 is similar to the inner circumferential contour shape of the winding portion 20.

[0061] The middle core portion 6 comprises a first end 6A and a second end 6B. The first end 6A connects to the inner end face 4A of the first end core portion 4. The second end 6B connects to the inner end face 5A of the second end core portion 5. At least a portion of the first end 6A and the second end 6B may protrude from the end of the winding portion 20. This protruding portion is also part of the middle core portion 6. In other words, the length of the middle core portion 6 along the first direction D1 may be longer than the length of the winding portion 20 along the first direction D1.

[0062] As shown in Figure 3, the middle core portion 6 comprises a first portion 61 and a second portion 62 made of different materials.

[0063] The first portion 61 is located at the first end 6A and the second end 6B. As described above, the first portion 41 of the first end core 4 and the first portion 61 of the first end 6A are integrally molded columnar powder compacts. A part of this powder compact is the first portion 61 of the first end 6A. Similarly, the first portion 51 of the second end core 5 and the first portion 61 of the second end 6B are integrally molded columnar powder compacts. A part of this powder compact is the first portion 61 of the second end 6B. In this example, the middle core 6 has two first portions 61.

[0064] The second portion 62 has a portion located in the central region between the first end 6A and the second end 6B. The central region is the region located inside the coil 2 in the middle core portion 6. When the second portion 62 is located in the central region, it is easier to lower the permeability of the magnetic core 3 compared to when the first portion 61 is located throughout the entire middle core portion 6. Lower permeability of the magnetic core 3 makes it easier to reduce the gap provided in the magnetic core 3. Reducing the gap makes it easier to reduce leakage flux from the gap. The magnetic core 3 in this example consists entirely of a compacted powder molded body and a molded body of a composite material, and does not have a gap made of a non-magnetic material.

[0065] In this example, the second portion 62 is also located on a part of the first end 6A and a part of the second end 6B. The second portion 62 of the first end 6A covers a part of the circumferential surface of the first portion 61. A notch 65 is provided in the second portion 62 of the first end 6A. Due to this notch 65, the first portion 61 of the first end 6A has a portion that is not covered by the second portion 62. A positioning portion 85 for the spacer 8, which will be described later with reference to Figure 4, is located in the notch 65. The positioning portion 85 located in the notch 65 is in contact with the first portion 61 of the first end 6A. The positioning portion 85 is in contact with a part of the first portion 61 of the first end 6A, thereby positioning the first portion 61 of the first end 6A relative to the spacer 8. The second portion 62 of the first end 6A is provided integrally with both the second portion 62 of the central region and the second portion 42 of the first end core portion 4. The second portion 62 of the second end 6B also covers a part of the circumferential surface of the first portion 61. A notch 65 is also provided in the second portion 62 of the second end portion 6B. A positioning portion 85 positioned in this notch 65 contacts a part of the first portion 61 of the second end portion 6B, thereby positioning the first portion 61 of the second end portion 6B relative to the spacer 8. The second portion 62 of the second end portion 6B is integrally provided with both the second portion 62 of the central region and the second portion 52 of the second end core portion 5.

[0066] In this example, the second portion 42 of the first end core portion 4, the second portion 52 of the second end core portion 5, and the second portion 62 of the middle core portion 6 are integrally molded. An integrally molded product made of composite material is arranged across the first end core portion 4, the second end core portion 5, and the middle core portion 6. When the second portion 42 of the first end core portion 4, the second portion 52 of the second end core portion 5, and the second portion 62 of the middle core portion 6 are integrally molded, the first end core portion 4 and the middle core portion 6, and the second end core portion 5 and the middle core portion 6, are easily joined together.

[0067] [Side Core Section] As shown in Figure 3, the side core section 7 is arranged to connect to the inner end surface 4A of the first end core section 4 and the inner end surface 5A of the second end core section 5. The side core section 7 is a columnar body extending in the first direction D1. In this example, there is one side core section 7. There may also be two side core sections 7. The two side core sections 7 are arranged to sandwich the winding section 20.

[0068] As shown in Figure 3, the side core portion 7 of this example is formed entirely by a second portion 72. The side core portion 7 of this example does not have a first portion. The second portion 72 of the side core portion 7 is integrally provided with the second portion 42 of the first end core portion 4 and the second portion 52 of the second end core portion 5. The second portion 42 of the first end core portion 4, the second portion 52 of the second end core portion 5, and the second portion 72 of the side core portion 7 are integrally molded. An integrally molded product made of composite material is arranged across the first end core portion 4, the second end core portion 5, and the side core portion 7. When the second portion 42 of the first end core portion 4, the second portion 52 of the second end core portion 5, and the second portion 72 of the side core portion 7 are integrally molded, the first end core portion 4 and the side core portion 7, and the second end core portion 5 and the side core portion 7 are easily joined together.

[0069] The side core portion 7 is provided with through holes 7h that penetrate in the second direction D2. In this example, two through holes 7h are provided at intervals from each other. The through holes 7h are traces left by pins (not shown) that fix the spacers 8, which will be described later, during the manufacturing process of the reactor 1.

[0070] [Material of the first part] The first parts 41, 51, and 61 are formed from compacted soft magnetic powder. The compacted powder is formed by pressure molding raw material powder containing soft magnetic powder. The compacted powder can have a higher proportion of soft magnetic powder compared to a molded body made of composite material. A compacted powder with a high proportion of soft magnetic powder has high magnetic permeability. The proportion of soft magnetic powder in the compacted powder is, for example, more than 80% by volume, and more specifically, 85% or more by volume, when the compacted powder is considered as 100% by volume. The raw material powder may also contain a lubricant.

[0071] Soft magnetic powder is formed, for example, from 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.

[0072] [Material of the second part] The second parts 42, 52, and 62 are formed from a molded composite material in which soft magnetic powder is dispersed in resin. The molded composite material is manufactured by filling a mold with a raw material in which soft magnetic powder is mixed and dispersed in unsolidified resin, and then solidifying the resin. The magnetic properties of the composite material, such as permeability or saturation magnetic flux density, can be easily controlled by adjusting the content ratio of soft magnetic powder in the resin. In particular, the composite material is easy to adjust to reduce the content ratio of soft magnetic powder, making it easy to lower the permeability. Although the molded composite material has lower permeability than the compacted powder molded material, it is less prone to magnetic saturation in high-current environments and has low iron loss. The molded composite material is easier to mold into complex shapes compared to the compacted powder molded material.

[0073] The soft magnetic powder used to form the molded composite body is the same as the soft magnetic powder used to form the compacted powder body described above. The soft magnetic powder content in the molded composite body is, for example, 20% to 80% by volume, assuming the composite material is 100% by volume.

[0074] The resin used to form the molded composite 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 is, for example, 20% to 80% by volume, assuming the composite material is 100% by volume.

[0075] The composite material may contain fillers in addition to the resin. Fillers contribute to improved heat dissipation. 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.

[0076] The content ratio of soft magnetic powder in a compacted molded body and the content ratio of soft magnetic powder in a composite molded body are considered equivalent to the area ratio of soft magnetic powder in the cross-section of the molded body. The content ratio of soft magnetic powder in the molded body is determined as follows: Observe the cross-section of the molded body with an SEM (scanning electron microscope) and acquire an observation image. The cross-section of the molded body can be any cross-section. The magnification of the SEM should be between 200x and 500x. Acquire at least 10 observation images. The total cross-sectional area should be 0.1 cm². ２ The above procedure is followed. One observation image may be obtained for each cross-section, or multiple observation images may be obtained for each cross-section. Each obtained observation image is processed to extract the contours of the particles. The image processing may be, for example, binarization. The area ratio of soft magnetic particles is calculated for each observation image, and the average value of these area ratios is determined. This average value is considered to be the content ratio of soft magnetic powder.

[0077] ≪Spacer≫ The spacer 8 is made of an insulating material. The spacer 8 is a component for insulating the space between the coil 2 and the magnetic core 3. The spacer 8 is also a component for positioning the first end core portion 4, the second end core portion 5, and the middle core portion 6 relative to each other, as well as for positioning the coil 2 and the magnetic core 3 relative to each other.

[0078] As shown in Figures 1 and 4, the spacer 8 in this example comprises a first spacer 81 and a second spacer 82. In Figure 4, for the sake of explanation, the state in which the first portion 51 of the second end core portion 5 and the first portion 61 of the middle core portion 6 are assembled as an integral molded product to the second spacer 82 is shown.

[0079] The first spacer 81 comprises a main body portion 83, a through hole 84, a positioning portion 85, and a side portion 89. The second spacer 82 comprises a main body portion 83, a through hole 84, and a positioning portion 85, but does not have a side portion 89. The second spacer 82 has the same configuration as the first spacer 81, except that it does not have a side portion 89. In the following description of the spacer 8, the first spacer 81 and the second spacer 82 will not be distinguished and will simply be referred to as spacer 8. Also, the first end core portion 4 and the second end core portion 5 will not be distinguished and will be referred to as end core portions 4 and 5.

[0080] As shown in Figure 1, the main body portion 83 is a plate-shaped member positioned between the end face of the coil 2 and the end core portions 4 and 5. The surface of the main body portion 83 facing the end face of the coil 2 has a helical circumferential surface of one turn, corresponding to the shape of the end face of the coil 2. The surface of the main body portion 83 facing the end core portions 4 and 5 is flat.

[0081] As shown in Figure 4, the through-hole 84 penetrates both the front and back surfaces of the main body portion 83. The through-hole 84 is provided so that the first portion 61 of the middle core portion 6 is inserted through it. Specifically, it is provided so that the integrally molded product of the first portions 41 and 51 of the end core portions 4 and 5 and the first portion 61 of the middle core portion 6 is inserted through it. When viewed along the axis of the through-hole 84, the through-hole 84 has a cross-shaped inner circumferential contour.

[0082] The positioning portion 85 is provided on the inner circumferential surface of the through hole 84 at a location facing the second direction D2. The two positioning portions 85 protrude inward into the through hole 84 compared to the location on the inner circumferential surface of the through hole 84 facing the third direction D3. The positioning portion 85 protrudes inward into the through hole 84 and also protrudes inward into the coil 2 along the first direction D1. The positioning portion 85 is in contact with the integrally molded product. In particular, the portion of the positioning portion 85 that protrudes inward into the coil 2 is in contact with the first portion 61 of the middle core portion 6. In this example, the positioning portion 85 is provided to support the entire length of the short side and both ends of the long side of the first portion 61. In this example, the positioning portion 85 is a C-shaped portion provided on the inner circumferential surface of the through hole 84 at a location facing the second direction D2. The integrally molded product is positioned relative to the main body portion 83 by the first portion 61 being in contact with the positioning portion 85.

[0083] When the integrally molded product is inserted through the through hole 84, the surface of the integrally molded product facing the second direction D2 is in contact with the positioning portion 85 and positioned, and a gap 88 is formed between the surface of the integrally molded product facing the third direction D3 and the inner circumferential surface of the through hole 84. The second portion 62 of the middle core portion 6 is inserted through this gap 88. Through this gap 88, the second portions 42 and 52 of the end core portions 4 and 5 and the second portion 62 of the middle core portion 6 are integrally provided.

[0084] The side portion 89 of the first spacer 81 is positioned between the coil 2 and the side core portion 7. The surface of the side portion 89 facing the coil 2 is formed in an arc shape corresponding to the outer shape of the coil 2. The first spacer 81 is formed in an L shape with the main body portion 83 and the side portion 89. The tip of the side portion 89 engages with the main body portion 83 of the second spacer 82.

[0085] The insulating material forming the spacer 8 is, for example, PPS resin, LCP, PA resin, PBT resin, acrylonitrile butadiene styrene (ABS) resin, or polytetrafluoroethylene (PTFE) resin. Alternatively, the material for the spacer 8 may be a thermosetting resin such as an unsaturated polyester resin, epoxy resin, urethane resin, or silicone resin. These resins may contain ceramic fillers. The ceramic fillers are, for example, non-magnetic powders such as alumina or silica.

[0086] If there are multiple winding sections 20, the through holes 84 in the spacer 8 are provided in proportion to the number of winding sections 20. The positioning section 85 is provided for each of the multiple through holes 84 at a location on the inner circumferential surface of the through hole 84 that faces the second direction D2. If there are multiple winding sections 20, the side core section 7 is not provided, so the side section 89 is not essential.

[0087] <Method for Manufacturing a Reactor> The method for manufacturing a reactor according to the embodiment will be described with reference to Figure 6 and, as appropriate, Figures 1 to 5. The method for manufacturing a reactor comprises a first step of arranging a coil 2 and a columnar core piece, in this example a set of a first core 91 and a second core 92, inside a mold 9, and a second step of filling the inside of the mold 9 in which the set of pieces is arranged with a composite material 93.

[0088] The first core 91 and the second core 92 are formed from compacted soft magnetic powder. The composite material 93 is formed by dispersing soft magnetic powder in a resin.

[0089] <First Step> In the first step, a set of components in which a part of the first core 91 is placed inside the first end of the coil 2 and a part of the second core 92 is placed inside the second end of the coil 2 is placed inside the mold 9. In this example, the first spacer 81 is placed facing the first end of the coil 2, and the second spacer 82 is placed facing the second end of the coil 2.

[0090] A portion of the first core 91 is inserted through the through hole 84 (Figure 4) of the first spacer 81. The first core 91 is positioned relative to the main body 83 of the first spacer 81 by the positioning part 85 shown in Figure 4. A portion of the second core 92 is inserted through the through hole 84 of the second spacer 82. The second core 92 is positioned relative to the main body 83 of the second spacer 82 by the positioning part 85. The first spacer 81 and the second spacer 82 are fixed to the mold 9. Thus, the first core 91 and the second core 92 are positioned in two directions, the second direction D2 and the third direction D3, by the positioning part 85.

[0091] The mold 9 is equipped with magnets 95 and 96. Magnet 95 is positioned facing the end face of the first core 91. The end face of the first core 91 is attracted to magnet 95, thereby positioning the first core 91 with respect to the first direction D1. Magnet 96 is positioned facing the end face of the second core 92. The end face of the second core 92 is attracted to magnet 96, thereby positioning the second core 92 with respect to the first direction D1.

[0092] Magnets 95 and 96 should be appropriately selected to have an adsorption force and size that allows them to attract the first core 91 and the second core 92 to such an extent that the flow of the composite material 93 in the second step does not cause the first core 91 and the second core 92 to shift from their predetermined positions.

[0093] In this example, although not shown, the mold 9 is equipped with pins for fixing the first spacer 81 and the second spacer 82. The pins include a pin that presses against the main body portion 83 (Figure 4) of the first spacer 81, a pin that presses against the main body portion 83 of the second spacer 82, and a pin that presses against the side portion 89. The first spacer 81 and the second spacer 82 are fixed to the mold 9 by the pins. A space is provided between the side portion 89 and the inner surface of the mold 9.

[0094] ≪Second Step≫ In the second step, with the end face of the first core 91 attracted to the magnet 95 and the end face of the second core 92 attracted to the magnet 96, the composite material 93 is filled into the mold 9 in which the assembly is arranged. The composite material 93 filled into the mold 9 covers the entire circumferential surface of the coil 2 located outside the first core 91 and the second core 92. The end faces of the first core 91 and the second core 92 are attracted to the magnets 95 and 96 and are in contact with the inner surface of the mold 9, so they are not covered by the composite material 93. The composite material 93 is also filled into the inside of the coil 2 through the gap 88 (Figure 4) between the first spacer 81 and the first core 91, and the gap 88 between the second spacer 82 and the second core 92. The composite material 93 is also filled into the space between the side portion 89 and the mold 9. The composite material 93 filled into the mold 9 solidifies while shrinking.

[0095] Of the first core 91, a portion located inside the through-hole 84 of the coil 2 and the first spacer 81 becomes the first portion 61 of the first end 6A of the middle core 6, and a portion located outside the coil 2 becomes the first portion 41 of the first end core 4. Of the second core 92, a portion located inside the through-hole 84 of the coil 2 and the second spacer 82 becomes the first portion 61 of the second end 6B of the middle core 6, and a portion located outside the coil 2 becomes the first portion 51 of the second end core 5.

[0096] The composite material 93 that covers and solidifies the entire circumferential surface of the coil 2 located outside the first core 91 becomes the second portion 42 of the first end core portion 4. Since the end face of the first core 91 is attracted to the magnet 95 and in contact with the inner surface of the mold 9, the end face of the first portion 41 is not covered by the second portion 42. The composite material 93 that covers and solidifies the entire circumferential surface of the coil 2 located outside the second core 92 becomes the second portion 52 of the second end core portion 5. Since the end face of the second core 92 is attracted to the magnet 96 and in contact with the inner surface of the mold 9, the end face of the first portion 51 is not covered by the second portion 52. The composite material 93 that is filled and solidified inside the coil 2 becomes the second portion 62 of the middle core portion 6. The composite material 93 that is filled and solidified in the space between the side portion 89 and the mold 9 becomes the second portion 72 of the side core portion 7.

[0097] In the above reactor manufacturing method, since the end faces of the first core 91 and the second core 92 are attracted to the magnets 95 and 96, the first core 91 and the second core 92 do not move even when subjected to the flow of the composite material 93. In the above reactor manufacturing method, as the composite material 93 solidifies, a magnetic core 3 can be manufactured in which the first parts 41, 51, 61 and the second parts 42, 52, 62, 72, which are made of different materials, are well joined with a sufficient contact area.

[0098] <Converter / Power Conversion Device> The reactor 1 described above can be used for applications that meet 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 1 described above is typically used as a component of a converter installed in vehicles such as electric vehicles and hybrid vehicles, or as a component of a power conversion device equipped with this converter.

[0099] As shown in Figure 7, a vehicle 1200 such as a hybrid vehicle or an 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 driving. The motor 1220 is typically a three-phase AC motor, which drives the wheels 1250 during driving and functions as a generator during regeneration. In the case of a hybrid vehicle, the vehicle 1200 is equipped with an engine 1300 in addition to the motor 1220. In Figure 7, the charging point of the vehicle 1200 is an inlet, but it may also be equipped with a plug.

[0100] The power conversion device 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.

[0101] As shown in Figure 8, 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 coil property 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 the reactor 1 described above.

[0102] Vehicle 1200 is equipped with a 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 is a power source for auxiliary equipment 1240, and which converts the high voltage of the main battery 1210 to a low voltage. Converter 1110 typically performs DC-DC conversion, while the power supply device converter 1150 and the 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 the auxiliary power converter 1160 have the same or similar configuration as the reactor 1 described above, and reactors with appropriately changed size and shape can be used. Furthermore, the reactor 1 described above can also be used in converters that convert input power, such as converters that only boost voltage or converters that only step down voltage.

[0103] 1 Reactor 2 Coil 20 Winding section, 21, 22 Winding end 3 Magnetic core 4 First end core section 4A Inner end face, 4B Outer end face 41 First section, 410 Outer end face, 415 Circumferential surface 42 Second section, 420 Outer end face 4c Notch, 4h Through hole 45 Envelope shape, 45L Long side, 45S Short side 5 Second end core section 5A Inner end face, 5B Outer end face 51 First section, 510 Outer end face, 515 Circumferential surface 52 Second section 5c Notch, 5h Through hole 6 Middle core section 6A First end, 6B Second end 61 First section, 62 Second section 65 Notch 7 Side core section 72 Second section 7h Through hole 8 Spacer 81 82 First spacer, 83 Second spacer, 84 Main body, 85 Through hole, 88 Positioning part, 89 Gap, 9 Side part, 9 Mold, 91 First core, 92 Second core, 93 Composite material, 95, 96 Magnet, 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 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. The device comprises a coil and a magnetic core, the magnetic core comprising two end core portions and a middle core portion, the two end core portions extending in a direction intersecting the axis of the coil so as to sandwich the coil, each of the two end core portions comprising an inner end face and an outer end face, the inner end face facing the coil, the outer end face being the back surface of the inner end face, the middle core portion having a portion disposed inside the coil and extending in a first direction along the axis of the coil so as to connect to the inner end faces of the two end core portions, each of the two end core portions and the middle core portion comprising a first portion and a second portion, the first portion being formed from a compacted molded body of soft magnetic powder, the second portion being formed from a molded body of a composite material in which soft magnetic powder is dispersed in a resin, the first portion of each of the two end core portions forming a part of the outer end face and extending in the first direction, the first portion of the middle core portion having a portion provided integrally with the first portion of each of the two end core portions and disposed inside the coil. The second portion of each of the two end core portions is a reactor, which is arranged to cover the entire circumferential surface of the first portion, excluding the outer end face.

2. The reactor according to claim 1, wherein the number of first portions of the middle core portion is two, and the second portion of the middle core portion is located between the two first portions of the middle core portion.

3. The reactor according to claim 1 or claim 2, wherein the second portion of each of the two end core portions forms a part of the outer end surface, and the outer end surface of the first portion and the outer end surface of the second portion are flush.

4. The reactor according to any one of claims 1 to 3, further comprising a spacer, the spacer comprising a main body, a through hole, and a positioning portion, the main body being disposed between the end face of the coil and the end core portion, the through hole being provided in the main body so as to allow the first portion of the middle core portion to pass through, and the positioning portion being provided on the inner circumferential surface of the through hole so as to position the first portion of the middle core portion relative to the main body by contacting a part of the first portion of the middle core portion.

5. The reactor according to any one of claims 1 to 4, wherein the number of coils is one, the magnetic core comprises a side core portion, and the side core portion extends in the first direction outside the coil so as to connect to the inner end faces of the two end core portions.

6. The reactor according to claim 5, further comprising a spacer, the spacer having a side portion disposed between the coil and the side core portion.

7. The reactor according to any one of claims 1 to 6, wherein each of the two end core portions has a rectangular envelope shape with a long side and a short side when viewed from the first direction.

8. The reactor according to any one of claims 1 to 7, wherein the second portion of each of the two end core portions and the middle core portion is a single molded product.

9. A converter comprising the reactor described in any one of claims 1 to 8.

10. A power conversion device comprising the converter described in claim 9.

11. A method for manufacturing a reactor, comprising: a first step of arranging an assembly of a coil and a columnar core piece inside a mold; and a second step of filling the inside of the mold in which the assembly is arranged with a composite material, wherein the core piece is formed from a compacted molded body of soft magnetic powder, the composite material has soft magnetic powder dispersed in a resin, the mold is provided with magnets at locations facing at least one of the end faces of both end faces of the core piece, in the first step a portion of the core piece is placed inside the coil, and in the second step, with the end face of the core piece attracted to the magnet, the entire circumferential surface of the core piece that is located outside the coil is covered with the composite material.

Images