Core piece, reactor, converter, and power conversion device

Abstract

To provide a core piece which is formed by satisfactorily bonding a first part and a second part having different materials, keeps high inductance even under large-current use environment, and enables manufacture of a reactor with low loss.SOLUTION: A core piece for constituting a magnetic core arranged inside and outside a coil includes a first block part which is arranged so as to face the end face of the coil, and a plurality of second block parts which have side faces facing any one surface of an inside surface and an outside surface of the coil, and are arranged so that the side faces face each other, wherein the first block part includes a first part composed of a compressed molded body of soft magnetic powder, and a second part composed of a molded body of a composite material in which soft magnetic powder is dispersed in a resin, the first part and the second part are overlapped with each other in a direction along the height of the first block part, and a ratio of the height of the first part to the height of the first block is more than 0.5 and less than 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

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

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

[0004] It is required to manufacture a reactor that maintains high inductance and has low loss even in a large current operating environment by using a core piece that combines a first portion and a second portion. In a core piece that combines a first portion and a second portion made of different materials, it is required that the first portion and the second portion are well joined.

[0005] One object of the present disclosure is to provide a core piece that can be used to manufacture a reactor in which a first portion and a second portion made of different materials are well joined and that maintains high inductance and low loss even in a high current usage environment. Another object of the present disclosure is to provide a reactor that includes the core piece. Another object of the present disclosure is to provide a converter that includes the reactor. Another object of the present disclosure is to provide a power conversion device that includes the converter. [Means for solving the problem]

[0006] The core piece of the present disclosure is a core piece for forming a magnetic core arranged inside and outside a coil, and includes a first block portion arranged to face an end face of the coil, and a plurality of second block portions having side faces facing either the inner surface or the outer surface of the coil and arranged so that the side faces face each other. The first block portion includes a first portion constituted by a compressed powder compact of soft magnetic powder, and a second portion constituted by a compact of a composite material in which soft magnetic powder is dispersed in a resin. The first portion and the second portion overlap in a direction along the height of the first block portion. The ratio of the height of the first portion to the height of the first block portion is greater than 0.5 and less than 1. The height of the first block portion and the height of the first portion are each a length along a direction perpendicular to both the direction along the axis of the coil and the direction in which the plurality of second block portions are arranged. Effect of the Invention

[0007] The core piece of the present disclosure is formed by satisfactorily joining a first portion and a second portion made of different materials, and can be used to manufacture a reactor that maintains high inductance and low loss even in an operating environment involving large currents. [Brief description of the drawings]

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

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

[0010] (1) A core piece according to an embodiment of the present disclosure is a core piece for forming a magnetic core arranged inside and outside a coil, and includes a first block portion arranged to face an end face of the coil, and a plurality of second block portions having side faces facing either the inner or outer surface of the coil and arranged so that the side faces face each other. The first block portion includes a first portion constituted by a compressed powder compact of soft magnetic powder, and a second portion constituted by a compact of a composite material in which soft magnetic powder is dispersed in a resin. The first portion and the second portion overlap in a direction along the height of the first block portion. The ratio of the height of the first portion to the height of the first block portion is greater than 0.5 and less than 1. The height of the first block portion and the height of the first portion are each a length along a direction perpendicular to both the direction along the axis of the coil and the direction in which the plurality of second block portions are arranged.

[0011] The core pieces allow the manufacture of a reactor that maintains high inductance and has low loss even in a high current operating environment. The powder compact has a higher magnetic permeability than a composite material compact. When the first portion made of the powder compact is arranged within a predetermined height range of the first block portion, leakage magnetic flux from the first block portion can be suppressed, and loss deterioration can be suppressed. On the other hand, the powder compact is prone to magnetic saturation. Since the first block portion is arranged to face the end face of the coil, in other words, the first block portion is arranged outside the coil, the effect of the powder compact arranged on the first block portion on magnetic saturation is relatively small, and high inductance can be maintained. Since the first portion and the second portion overlap in a direction along the height of the first block portion, they are well joined over a relatively large surface area.

[0012] (2) In the core piece described in (1) above, the second block portions may be formed of a molded body of the composite material so as to be continuous with the second region.

[0013] When the second block portion is made of a composite material molded body, the gap provided in the middle of the second block portion may be small. For example, when the gap of the second block portion arranged in the coil is small, the leakage flux from the gap is small, and the deterioration of loss can be suppressed. Since the composite material molded body is configured so that the second portion of the first block portion and the second block portion are continuous, the first block portion and the second block portion are firmly bonded to each other. When the first block portion and the second block portion are firmly bonded to each other, the first block portion and the second block portion can be easily handled as a single unit.

[0014] (3) In the core piece described in (1) or (2) above, the first block portion may have a first surface and a second surface facing each other in a direction along the height of the first block portion, the first portion may have the first surface, and the second portion may have the second surface.

[0015] In the core piece of (3) above, the first portion and the second portion are easily disposed in the height direction of the first block portion.

[0016] (4) In the core piece according to any one of (1) to (3), the first portion and the second portion may overlap in a direction along a thickness of the first block portion, and a ratio of a thickness of the first portion to a thickness of the first block portion may be 0.6 or more. Each of the thickness of the first block portion and the thickness of the first portion is a length along an axis of the coil.

[0017] When the first and second portions overlap in the direction along the thickness of the first block portion in addition to the direction along the height of the first block portion, they are joined well over a relatively large surface. If the thickness ratio is 0.6 or more, leakage flux from the first block portion can be further suppressed, and deterioration of loss can be further suppressed.

[0018] (5) In the core piece described in any one of (1) to (4) above, the first block portion may have an outer end surface facing outward in a direction along the axis of the coil, and the first portion may have the outer end surface.

[0019] In the core piece (5) above, the first portion and the second portion can be easily disposed in the thickness direction of the first block portion.

[0020] (6) A reactor according to an embodiment of the present disclosure comprises a magnetic core formed by combining first core pieces and second core pieces, and a coil arranged in a part of the magnetic core, wherein at least one of the first core pieces and the second core pieces is a core piece described in any one of (1) to (5) above.

[0021] A reactor equipped with a magnetic core including the above-mentioned core pieces maintains high inductance and low loss even in an operating environment of large currents.

[0022] (7) A converter according to an embodiment of the present disclosure includes the reactor described in (6) above.

[0023] A converter equipped with the above reactor maintains high inductance and low loss even in a high current operating environment.

[0024] (8) A power conversion device according to an embodiment of the present disclosure includes the converter described in (7) above.

[0025] A power conversion device including the above converter maintains high inductance and low loss even in a high current operating environment.

[0026] [Details of the embodiment of the present disclosure] Specific examples of the embodiments of the present disclosure will be described below with reference to the drawings. The same reference numerals in the drawings indicate the same objects. In each drawing, for convenience of explanation, some of the configurations may be exaggerated or simplified. The dimensional ratios of each part in the drawings may also differ from the actual ratios. Note that the present invention is not limited to these examples, but is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0027] <Embodiment 1> <Core Piece> The core piece 1α of the first embodiment will be described with reference to FIG. 1 and FIG. 2. The core piece 1α is a component of the reactor 7 (FIG. 6) described later. The core piece 1α constitutes a magnetic core 8 arranged inside and outside the coil 9 (FIG. 6, FIG. 7) of the reactor 7. The core piece 1α includes a first block portion 110 and a plurality of second block portions 120. The first block portion 110 is arranged outside the winding portion 90 (FIG. 6, FIG. 7) of the coil 9. One of the features of the core piece 1α of the first embodiment is that the first block portion 110 includes a first portion 11 and a second portion 12, and the first portion 11 is arranged within a predetermined height range of the first block portion 110. The first portion 11 is a portion formed by powder compaction. The second portion 12 is a portion formed by a molded body of a composite material. In the core piece 1α of the first embodiment, the plurality of second block portions 120 also include the second portion 12. The core piece 1α of the first embodiment is an integral body formed by integrally molding a first block portion 110 and a plurality of second block portions 120. In the following, the materials of the first portion 11 and the second portion 12 will be described first, and then the configurations of the first block portion 110 and the second block portion 120 will be described in order. In each drawing, the first portion 11 is cross-hatched for easy understanding.

[0028] In the following, the first direction D1, the second direction D2, and the third direction D3 may be used for explanation. The first direction D1 is a direction along the axis of the winding portion 90 (FIGS. 6 and 7) of the coil 9. The direction along the axis of the winding portion 90 is also a direction along the axis of the second block portion 120. The second direction D2 is a direction in which the multiple second block portions 120 are arranged. The third direction D3 is a 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, each of the first direction D1, the second direction D2, and the third direction D3 is indicated by a single arrow. In the following, 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.

[0029] [First part] The first portion 11 is a region formed of a powder compact of soft magnetic powder. The powder compact is obtained by pressing raw powder containing soft magnetic powder. The powder compact can have a higher content of soft magnetic powder in the compact than a composite material compact described later. A powder compact with a high content of soft magnetic powder has high magnetic permeability. The content of soft magnetic powder in the powder compact is, for example, more than 80 volume %, 85 volume % or more, 90 volume % or more, or 95 volume % or more when the powder compact is taken as 100 volume %. The raw powder may contain a lubricant.

[0030] The soft magnetic powder is, for example, composed of soft magnetic metal particles, coated particles, or soft magnetic nonmetal particles. The coated particles include soft magnetic metal particles and an insulating coating provided on the outer periphery of the soft magnetic metal particles. The soft magnetic metal is, for example, pure iron or an iron-based alloy. The iron-based alloy is, for example, an Fe-Si alloy or an Fe-Ni alloy. The insulating coating is, for example, a phosphate. The soft magnetic nonmetal is, for example, a ferrite.

[0031] [Second part] The second portion 12 is an area constituted by a composite material compact in which soft magnetic powder is dispersed in resin. The composite material compact is manufactured by filling a raw material in which soft magnetic powder is mixed and dispersed in unsolidified resin into a mold, and solidifying the resin. The magnetic properties of the composite material, such as the magnetic permeability or saturation magnetic flux density, can be easily controlled by adjusting the content of the soft magnetic powder in the resin. In particular, the content of the soft magnetic powder in the composite material can be easily adjusted to be low, and the magnetic permeability can be easily reduced. Although the composite material compact has a lower magnetic permeability than the powder compact, it is difficult to magnetically saturate under a large current operating environment and has low iron loss. The composite material compact can be easily molded into a complex shape compared to the powder compact.

[0032] The soft magnetic powder constituting the composite material compact is the same as the soft magnetic powder constituting the above-mentioned powder compact. The content of the soft magnetic powder in the composite material compact is, for example, 20% by volume or more and 80% by volume or less, assuming the composite material to be 100% by volume.

[0033] The resin constituting the composite material molded body is, for example, a thermosetting resin or a thermoplastic resin. The thermosetting resin is, for example, an epoxy resin, a phenol resin, a silicone resin, or a urethane resin. The thermoplastic resin is, for example, a polyphenylene sulfide (PPS) resin, a polybutylene terephthalate (PBT), a polyamide (PA) resin, a liquid crystal polymer (LCP), a polyimide (PI) resin, or a fluororesin. The polyamide resin is, for example, nylon 6, nylon 66, or nylon 9T. The content of the resin in the composite material molded body is, for example, 20% by volume or more and 80% by volume or less, assuming that the composite material is 100% by volume.

[0034] The composite material may contain a filler in addition to the resin. The filler contributes to improving heat dissipation. For example, a powder made of a non-magnetic material such as ceramics or carbon nanotubes can be used as the filler. For example, the ceramics is an oxide, nitride, or carbide of a metal or non-metal. An example of an oxide is alumina, silica, or magnesium oxide. An example of a nitride is silicon nitride, aluminum nitride, or boron nitride. An example of a carbide is silicon carbide.

[0035] [First block part] The first block portion 110 is a region disposed so as to face an end surface 91 (FIGS. 6 and 7) of a wound portion 90 of the coil 9, which will be described later. The first block portion 110 may be referred to as an end core portion 5.

[0036] The first block portion 110 is disposed so as to connect the multiple second block portions 120 outside the winding portion 90. The shape of the first block portion 110 may be any shape that connects the multiple second block portions 120. The first block portion 110 in this example is a rectangular block body.

[0037] The first block portion 110 includes a first portion 11 and a second portion 12. The first portion 11 and the second portion 12 are configured to overlap in a direction along the height of the first block portion 110. The direction along the height of the first block portion 110 is a third direction D3. The first block portion 110 includes a first surface 111 and a second surface 112 that face each other in the third direction D3. In this example, the first portion 11 includes the first surface 111, and the second portion 12 includes the second surface 112. The first portion 11 of this example is configured as one block body including the first surface 111. The second portion 12 of this example is configured to cover the surface of the first portion 11 opposite to the first surface 111. The second portion 12 includes the second surface 112 by covering the first portion 11.

[0038] The first block portion 110 has an outer end surface 113 facing outward in the first direction D1. The outer end surface 113 of the present example is composed of a first portion 11 and a second portion 12. In other words, each of the first portion 11 and the second portion 12 of the present example is arranged to have an outer end surface 113. The first block portion 110 has two side surfaces 115 facing each other in the second direction D2. Each side surface 115 of the present example is composed of a first portion 11 and a second portion 12. In other words, each of the first portion 11 and the second portion 12 of the present example is arranged to have two side surfaces 115. The first portion 11 of the present example is composed of one block body including the first surface 111, a part of the outer end surface 113, and a part of each of the two side surfaces 115.

[0039] The ratio H1 / H0 of the height H1 of the first portion 11 to the height H0 of the first block portion 110 is greater than 0.5 and less than 1. The height of the first block portion 110 and the height of the first portion 11 are each a length along the third direction D3. As described above, a powder compact has a higher magnetic permeability than a compact made of a composite material. If the ratio H1 / H0 is greater than 0.5, the first portion 11 made of the powder compact is disposed over a relatively wide range of the first block portion 110. If the first portion 11 is disposed over a relatively wide range, leakage flux from the first block portion 110 can be suppressed, and deterioration of loss can be suppressed.

[0040] As described above, the powder compact is easily magnetically saturated. Since the first block portion 110 is disposed so as to face the end face 91 (FIGS. 6 and 7) of the winding portion 90, in other words, the first block portion 110 is disposed outside the winding portion 90, the influence of the powder compact disposed on the first block portion 110 on the magnetic saturation is relatively small. Therefore, the first block portion 110 can maintain a high inductance.

[0041] If the ratio H1 / H0 is less than 1, the first portion 11 and the second portion 12 are joined over a relatively large surface area. In this example, the second portion 12 is joined over the entire surface of the first portion 11 opposite the first surface 111. If the ratio H1 / H0 is less than 1, the first portion 11 and the second portion 12 are joined to each other satisfactorily.

[0042] The ratio H1 / H0 may be 0.6 or more and less than 1, 0.7 or more and less than 1, 0.8 or more and less than 1, or 0.8 or more and less than 0.9.

[0043] The second portion 12 of the first block portion 110 is connected to a second portion 12 of the second block portion 120, which will be described later. The second portion 12 of the first block portion 110 is a thin plate-like portion protruding from each second block portion 120. The second portion 12 of the first block portion 110 integrates the multiple second block portions 120, which will be described later. The height of the second portion 12 of the first block portion 110 changes depending on the ratio H1 / H0.

[0044] The first portion 11 and the second portion 12 of the first block portion 110 may overlap in a direction along the thickness of the first block portion 110. The direction along the thickness of the first block portion 110 is a first direction D1. In this example, the first portion 11 and the second portion 12 of the first block portion 110 do not overlap in a direction along the thickness of the first block portion 110. The first portion 11 of this example is disposed over the entire thickness of the first block portion 110. The ratio T1 / T0 of the thickness T1 of the first portion 11 to the thickness T0 of the first block portion 110 will be described in embodiment 3 with reference to FIG. 4.

[0045] The first portion 11 and the second portion 12 of the first block portion 110 may overlap in a direction along the width of the first block portion 110. The direction along the width of the first block portion 110 is a second direction D2. In this example, the first portion 11 and the second portion 12 of the first block portion 110 do not overlap in a direction along the width of the first block portion 110. The first portion 11 in this example is disposed across the entire width of the first block portion 110. The ratio W1 / W0 of the width W1 of the first portion 11 to the width W0 of the first block portion 110 will be described in embodiment 4 with reference to FIG. 5.

[0046] [Second block part] Each second block portion 120 is an area having a side surface 125 facing either the inner surface 92 or the outer surface 93 (FIG. 7) of the winding portion 90. The multiple second block portions 120 are arranged so that the side surfaces 125 face each other. Each second block portion 120 has multiple side surfaces 125. In each second block portion 120, any one of the multiple side surfaces 125 may face the side surface 125 of the adjacent second block portion 120. The second block portion 120 arranged inside the winding portion 90 has a side surface 125 facing the inner surface 92 of the winding portion 90. The second block portion 120 arranged inside the winding portion 90 may be called a middle core portion 21. The second block portion 120 arranged outside the winding portion 90 has a side surface 125 facing the outer surface 93 of the winding portion 90. The second block portion 120 arranged outside the winding portion 90 may be called a side core portion 31, 41.

[0047] The three second block portions 120 are connected to the same surface of one first block portion 110 and extend in the same direction. In each drawing, the boundaries between the first block portion 110 and each second block portion 120 are indicated by two-dot chain lines.

[0048] Of the multiple second block portions 120, the middle core portion 21 has a portion that is disposed inside the winding portion 90 (FIGS. 6 and 7). The middle core portion 21 is a portion that extends in a direction intersecting with the first block portion 110, and may have a portion that is disposed outside the winding portion 90. In other words, the middle core portion 21 may have a portion that is disposed inside the winding portion 90 and a portion that is disposed outside the winding portion 90. The shape of the middle core portion 21 roughly corresponds to the inner peripheral shape of the winding portion 90. The middle core portion 21 in this example is a rectangular block body. The corners of the middle core portion 21 are rounded to fit the corners of the winding portion 90.

[0049] Of the multiple second block portions 120, two side core portions 31, 41 are arranged side by side with the middle core portion 21 outside the winding portion 90 (FIGS. 6 and 7). The two side core portions 31, 41 are arranged to sandwich the middle core portion 21 with a gap between them. The shape of each side core portion 31, 41 may be a shape that allows the side core portion 31, 41 to be arranged side by side with the middle core portion 21. Each side core portion 31, 41 in this example is a rectangular block body. In this example, the two side core portions 31, 41 have the same shape and dimensions. The length of each side core portion 31, 41 in this example along the first direction D1 is longer than the length of the middle core portion 21 along the first direction D1. The length of each side core portion 31, 41 along the first direction D1 may be the same as or shorter than the length of the middle core portion 21 along the first direction D1. The length of each side core portion 31, 41 in the second direction D2 of the present example is shorter than the length of the middle core portion 21 in the second direction D2. The sum of the lengths of each side core portion 31, 41 in the second direction D2 of the present example is shorter than the length of the middle core portion 21 in the second direction D2. The sum of the lengths of each side core portion 31, 41 in the second direction D2 may be equal to or greater than the length of the middle core portion 21 in the second direction D2. The length of each side core portion 31, 41 in the third direction D3 of the present example is the same as the length of the middle core portion 21 in the third direction D3. The length of each side core portion 31, 41 in the third direction D3 may be shorter or longer than the length of the middle core portion 21 in the third direction D3. The shapes and dimensions of the two side core portions 31, 41 may be different.

[0050] Each second block portion 120 has at least the second portion 12. Each second block portion 120 may have only the second portion 12. At least one of the multiple second block portions 120 may have the first portion 11 and the second portion 12.

[0051] The second portion 12 of each second block portion 120 is provided, for example, so as to be continuous with the second portion 12 of the first block portion 110. The second portion 12 of each second block portion 120 is, for example, a molded product having no seam between it and the second portion 12 of the first block portion 110. Each second block portion 120 in this example is composed of only the second portion 12.

[0052] The second portion 12 of the first block portion 110 and the second portion 12 of each second block portion 120 may be made of a molded body of the same composite material. The second portion 12 of the first block portion 110 and the second portion 12 of each second block portion 120 may include a molded body of a different composite material. For example, the second portion 12 of the first block portion 110 and the second portion 12 of each second block portion 120 may be made of a molded body of a different composite material. Among the multiple second block portions 120, the second portion 12 of the middle core portion 21 arranged inside the winding portion 90 and the second portion 12 of the side core portions 31, 41 arranged outside the winding portion 90 may be made of a molded body of a different composite material. In this case, the second portion 12 of the first block portion 110 and the second portion 12 of the side core portions 31, 41 may be made of a molded body of the same composite material. For example, a portion disposed inside the winding portion 90 (FIGS. 6 and 7) and a portion disposed outside the winding portion 90 may be formed of molded bodies made of different composite materials.

[0053] The different composite materials refer to composite materials that are at least partially different in type and content. The different types of composite materials include different types of soft magnetic powder and different types of resin. The different types of soft magnetic powder refer to, for example, different compositions of soft magnetic powder. The different content of the composite materials refers to different content of soft magnetic powder in resin.

[0054] When the second block portion 120 includes the first portion 11, the first portion 11 is provided, for example, so as to be continuous with the first portion 11 of the first block portion 110. The first portion 11 of the first block portion 110 and the first portion 11 of the second block portion 120 may be provided discontinuously. An embodiment in which the second block portion 120 includes the first portion 11 and the second portion 12 will be described in embodiment 7 with reference to FIG. 9.

[0055] The core piece 1α of this example includes one first block portion 110 and three second block portions 120. The core piece 1α of this example has an E-shape constituted by the one first block portion 110 and the three second block portions 120.

[0056] <Core piece manufacturing method> The above-mentioned core piece 1α is manufactured, for example, by carrying out the following first, second, and third steps. The first, second, and third steps are carried out in this order.

[0057] [First step] In the first step, a mold and a partial core piece are prepared. The mold has a first space and a plurality of second spaces that communicate with each other. The first space is a space for molding the first block portion 110 described above. Each second space is a space for molding the second block portion 120 described above. Each second space extends in a direction intersecting with the first space and is arranged side by side with each other. The partial core piece is a powder compact of soft magnetic powder. The partial core piece is the first portion 11 of the first block portion 110 described above.

[0058] [Second process] In the second step, the partial core piece is disposed in a part of the first space, with the remainder of the first space being a space in which nothing is disposed with the partial core piece disposed therein.

[0059] [Third step] In the third step, a composite material having soft magnetic powder dispersed in resin is filled into the remainder of the first space and each of the second spaces so as to cover a portion of the partial core piece. When the composite material solidifies, it becomes the above-mentioned second portion 12. When the composite material filled into the remainder of the first space so as to cover a portion of the partial core piece solidifies, it becomes the above-mentioned second portion 12 of the first block portion 110. When the composite material filled into each of the second spaces solidifies, it becomes the above-mentioned second portion 12 of the second block portion 120.

[0060] <Embodiment 2> A core piece 1β of embodiment 2 will be described with reference to Fig. 3. The core piece 1β of embodiment 2 is different from the core piece 1α of embodiment 1 in the overlapping portion between the first portion 11 and the second portion 12 in the first block portion 110. The core piece 1β of embodiment 2 has the same configuration as the core piece 1α of embodiment 1 except for the overlapping portion.

[0061] In the core piece 1β of this example, the second portion 12 of the first block portion 110 is configured to sandwich the first portion 11 in the third direction D3. The first portion 11 of the first block portion 110 of this example does not include the first surface 111 and the second surface 112 of the first block portion 110. The first portion 11 of the first block portion 110 of this example is configured as one block body including a part of the outer end surface 113 of the first block portion 110 and a part of each of the two side surfaces 115. In this example, the second portion 12 of the first block portion 110 includes the first surface 111, the second surface 112, the remainder of the outer end surface 113, and the remainder of each of the two side surfaces 115.

[0062] In the core piece 1β of the present example, the ratio H1 / H0 of the height H1 of the first portion 11 to the height H0 of the first block portion 110 is also greater than 0.5 and less than 1. When the ratio H1 / H0 is greater than 0.5, leakage magnetic flux from the first block portion 110 can be suppressed regardless of where the first portion 11 is located in the direction along the height of the first block portion 110, and an increase in loss can be suppressed.

[0063] When the first portion 11 is disposed between the second portion 12, the first portion 11 and the second portion 12 are more effectively bonded to each other. In this example, the entire surfaces of two surfaces of the first portion 11 facing each other in the third direction D3 are bonded to the second portion 12.

[0064] <Embodiment 3> A core piece 1γ of embodiment 3 will be described with reference to Fig. 4. The core piece 1γ of embodiment 3 is different from the core piece 1α of embodiment 1 in the thickness T1 of the first portion 11 of the first block portion 110. The core piece 1γ of embodiment 3 has the same configuration as the core piece 1α of embodiment 1, except for the thickness T1 of the first portion 11.

[0065] In the core piece 1γ of this example, the first portion 11 and the second portion 12 of the first block portion 110 overlap not only in the direction along the height of the first block portion 110 but also in the direction along the thickness of the first block portion 110.

[0066] The second portion 12 of the first block portion 110 in this example includes a connecting portion 12A and a flange portion 12B. The connecting portion 12A is a plate-like member provided to connect a plurality of second block portions 120. Each of the second block portions 120 is connected to the same surface of the connecting portion 12A. A portion of the connecting portion 12A overlaps with the first portion 11 in a direction along the thickness of the first block portion 110. The flange portion 12B is a plate-like member provided to protrude from the connecting portion 12A in the first direction D1. The flange portion 12B overlaps with the first portion 11 in a direction along the height of the first block portion 110.

[0067] The ratio T1 / T0 of the thickness T1 of the first portion 11 to the thickness T0 of the first block portion 110 is, for example, 0.6 or more. The thickness T0 of the first block portion 110 includes the thickness of the connecting portion 12A and the protruding length of the flange portion 12B. The thickness of the connecting portion 12A is the length obtained by subtracting the thickness T1 from the thickness T0 shown in FIG. 4. The thickness of the connecting portion 12A may be as thin as a thin film. The dashed line shown in FIG. 4 indicates the boundary between the connecting portion 12A and the flange portion 12B. The thickness of the connecting portion 12A is the length between the dashed line and the two-dot chain line shown in FIG. 4. If the ratio T1 / T0 is 0.6 or more, the first portion 11 made of the powder compact is arranged over a relatively wide range of the first block portion 110. If the first portion 11 is arranged over a relatively wide range, leakage magnetic flux from the first block portion 110 can be suppressed, and deterioration of loss can be suppressed.

[0068] The ratio T1 / T0 may be 0.6 or more and 1 or less, 0.65 or more and 1 or less, 0.7 or more and 1 or less, 0.8 or more and 1 or less, 0.9 or more and 1 or less, or 1. When the ratio T1 / T0 is 1, the first portion 11 is disposed over the entire thickness of the first block portion 110, as shown in FIG.

[0069] The ratio T1 / T0 may be less than 1. When the ratio T1 / T0 is less than 1, the first portion 11 and the second portion 12 are joined to each other over a relatively large surface area. When the ratio T1 / T0 is less than 1, the first portion 11 and the second portion 12 are joined to each other satisfactorily.

[0070] The ratio T1 / T0 may be 0.6 or more and less than 1, 0.65 or more and less than 1, 0.7 or more and less than 1, or 0.8 or more and less than 0.9.

[0071] <Embodiment 4> A core piece 1δ of embodiment 4 will be described with reference to Fig. 5. The core piece 1δ of embodiment 4 is different from the core piece 1α of embodiment 1 in the width W1 of the first portion 11 of the first block portion 110. The core piece 1δ of embodiment 4 has the same configuration as the core piece 1α of embodiment 1, except for the width W1 of the first portion 11. For ease of explanation, Fig. 5 shows the core piece 1δ from a different direction than Fig. 1.

[0072] In the core piece 1δ of this example, the first portion 11 and the second portion 12 of the first block portion 110 also overlap in the direction along the width of the first block portion 110. The first portion 11 comprises a part of the first surface 111 and a part of the outer end surface 113 of the first block portion 110. The first portion 11 does not comprise a side surface 115. The second portion 12 covers the side surfaces of the first portion 11, thereby comprising the two side surfaces 115 of the first block portion 110. The second portion 12 also comprises the second surface 112 of the first block portion 110, the remainder of the first surface 111, and the remainder of the outer end surface 113.

[0073] The ratio W1 / W0 of the width W1 of the first portion 11 to the width W0 of the first block portion 110 is, for example, 0.3 or more. In this example, the corners of the first portion 11 are rounded. In this case, the width W1 of the first portion 11 is the widest width. If the ratio W1 / W0 is 0.3 or more, the first portion 11 made of a powder compact is arranged over a relatively wide range of the first block portion 110. If the first portion 11 is arranged over a relatively wide range, leakage magnetic flux from the first block portion 110 can be suppressed, and an increase in loss can be suppressed.

[0074] The ratio W1 / W0 may be 0.3 or more and 1 or less, 0.4 or more and 1 or less, 0.5 or more and 1 or less, 0.6 or more and 1 or less, 0.7 or more and 1 or less, 0.8 or more and 1 or less, 0.9 or more and 1 or less, or 1. When the ratio W1 / W0 is 1, the first portion 11 is disposed over the entire width of the first block portion 110, as shown in FIG.

[0075] The ratio W1 / W0 may be less than 1. When the ratio W1 / W0 is less than 1, the first portion 11 and the second portion 12 are joined to each other over a relatively large surface area. When the ratio W1 / W0 is less than 1, the first portion 11 and the second portion 12 are joined to each other satisfactorily.

[0076] The ratio W1 / W0 may be 0.3 or more and less than 1, 0.4 or more and less than 1, 0.5 or more and less than 1, 0.6 or more and less than 1, 0.7 or more and less than 1, 0.8 or more and less than 1, or 0.8 or more and less than 0.9.

[0077] <Embodiment 5> <Reactor> A reactor 7 of the fifth embodiment will be described with reference to FIG. 6 and FIG. 7. The reactor 7 includes a magnetic core 8 and a coil 9. The magnetic core 8 is configured by combining a first core piece 81 and a second core piece 82. The first core piece 81 and the second core piece 82 are split pieces that are split so that the magnetic core 8 is separated in the first direction D1. The coil 9 is disposed in a part of the magnetic core 8. One of the features of the reactor 7 of the fifth embodiment is that at least one of the first core piece 81 and the second core piece 82 is the core piece 1α of the first embodiment. At least one of the first core piece 81 and the second core piece 82 may be the core piece 1β of the second embodiment, the core piece 1γ of the third embodiment, or the core piece 1δ of the fourth embodiment. In this example, both the first core piece 81 and the second core piece 82 are the core piece 1α of the first embodiment. The first core piece 81 and the second core piece 82 are symmetrical with respect to a middle position in the first direction D1 of the magnetic core 8.

[0078] [Magnetic core] The magnetic core 8 is a magnetic member for forming a circular magnetic path by excitation of the coil 9. The magnetic core 8 in this example is configured in a θ shape as a whole by combining first core pieces 81 and second core pieces 82.

[0079] The magnetic core 8 includes a middle core portion 2, two side core portions 3 and 4, and two end core portions 5 and 6. In Figures 6 and 7, the boundaries between the middle core portion 21 and the end core portion 5, and the boundaries between the side core portions 3 and 4 and the end core portion 5 are indicated by dashed two-dot lines.

[0080] The middle core portion 2 has a portion disposed inside the winding portion 90 of the coil 9 described later. The middle core portion 2 of this example is constituted by the middle core portion 21 of the first core piece 81, the middle core portion 22 of the second core piece 82, and a gap 2g. The middle core portions 21 and 22 are one of the multiple second block portions 120 of the core piece 1α described above. The middle core portion 21 and the middle core portion 22 have the same length along the second direction D2. The middle core portion 21 and the middle core portion 22 have the same length along the third direction D3. The gap 2g 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. When the gap 2g is provided, the inductance of the reactor 7 can be easily adjusted. For example, a gap material (not shown) is disposed in the gap 2g. A known material can be used as the gap material. The material constituting the gap material is, for example, non-magnetic ceramics or resin. The gap 2g may be an air gap in which no gap material is disposed. In the case where the reactor 7 includes a molded resin portion described later, the gap 2g may be filled with a resin that constitutes the molded resin portion. In this case, the resin that constitutes the molded resin portion serves as a gap material.

[0081] The length of the middle core portion 2 in the first direction D1 is equal to or greater than the length of the wound portion 90 in the first direction D1. In this example, the length of the middle core portion 2 in the first direction D1 is slightly longer than the length of the wound portion 90 in the first direction D1. In other words, the middle core portion 2 has a portion that is disposed inside the wound portion 90 and a portion that is disposed outside the wound portion 90. Both end portions of the middle core portion 2 are located outside the wound portion 90.

[0082] The side core portion 3 is composed of a side core portion 31 of the first core piece 81 and a side core portion 32 of the second core piece 82. The side core portions 31 and 32 are one of the multiple second block portions 120 of the core piece 1α described above. In this example, no gap is provided between the side core portions 31 and 32. In other words, the end faces of the side core portions 31 and 32 are in contact with each other. The side core portion 4 is composed of a side core portion 41 of the first core piece 81 and a side core portion 42 of the second core piece 82. The side core portions 41 and 42 are one of the multiple second block portions 120 of the core piece 1α described above. In this example, no gap is provided between the side core portions 41 and 42. In other words, the end faces of the side core portions 41 and 42 are in contact with each other.

[0083] The end core portions 5 and 6 are the first block portion 110 of the core piece 1α described above.

[0084] In the magnetic core 8, one middle core portion 2, two side core portions 3, 4, and two end core portions 5, 6 are connected, so that when a coil 9, which will be described later, is excited, magnetic flux flows and a closed magnetic circuit is formed. As shown by the dashed arrows in Fig. 7, the magnetic flux flows from the middle core portion 2 to the end core portion 5, from the end core portion 5 to each of the two side core portions 3, 4, from each of the side core portions 3, 4 to the end core portion 6, and from the end core portion 6 to the middle core portion 2.

[0085] In this example, since both the first core laminations 81 and the second core laminations 82 are the core laminations 1α of embodiment 1, leakage magnetic flux from the end core portions 5, 6 can be suppressed, and an increase in loss can be suppressed.

[0086] 〔coil〕 The coil 9 includes at least one winding portion 90. The coil 9 in this example includes one winding portion 90. The winding portion 90 is formed by winding one wire in a spiral shape. Both ends of the wire are pulled out from each end of the winding portion 90. Terminal fittings (not shown) are attached to both ends of the wire pulled out from the winding portion 90. An external device (not shown) is connected to the terminal fittings. In Figs. 5 and 6, only the winding portion 90 is shown, and the ends of the wire are omitted.

[0087] The winding may be a known winding. The winding in this example is a coated rectangular wire made of a conductor wire having an insulating coating. The conductor wire is made of, for example, a rectangular copper wire. The insulating coating is made of, for example, enamel. The winding portion 90 in this example is an edgewise coil made by edgewise winding the coated rectangular wire.

[0088] The shape of the winding portion 90 is a square tube shape. That is, the shape of the end face 91 of the winding portion 90 in this example is a rectangular frame shape. The winding portion 90 has an inner side surface 92 and an outer side surface 93. The inner side surface 92 faces the middle core portion 2. There is a gap between the inner side surface 92 and the outer peripheral surface of the middle core portion 2. When the reactor 7 has a molded resin portion (not shown), this gap is filled with resin constituting the molded resin portion. The outer side surface 93 faces the side core portions 3 and 4. The end face 91 faces the end core portions 5 and 6. The corners of the winding portion 90 in this example are rounded. When the winding portion 90 has a square tube shape, the contact area between the winding portion 90 and the installation object is likely to be large compared to when the winding portion is a cylinder with the same cross-sectional area. When the contact area between the winding portion 90 and the installation object is large, the heat dissipation performance of the reactor 7 is improved. When the contact area between the winding portion 90 and the installation target is large, the installation state of the winding portion 90 relative to the installation target is likely to be stable.

[0089] 〔others〕 Although not shown, the reactor 7 may include a molded resin part. The molded resin part covers at least a part of the magnetic core 8. The molded resin part has a function of protecting the magnetic core 8 from the external environment. The molded resin part may further cover the coil 9. That is, the molded resin part is provided so as to cover at least a part of the assembly of the magnetic core 8 and the coil 9. The molded resin part integrates the magnetic core 8 and the coil 9. A part of the outer circumferential surface of the magnetic core 8 or at least a part of the outer circumferential surface of the coil 9 may be exposed from the molded resin part. If the molded resin part 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 part is provided between the middle core part 21 of the first core piece 81 and the middle core part 22 of the second core piece 82, the molded resin part provided therebetween functions as a gap material for the magnetic core 8. The resin constituting the molded resin part is, for example, the same resin as the resin of the composite material described above. The constituent material of the molded resin portion may contain the above-mentioned filler, similar to the composite material.

[0090] Although not shown, the reactor 7 may include a holding member. The holding member is disposed between the magnetic core 8 and the coil 9, and has a function of ensuring electrical insulation between the magnetic core 8 and the coil 9. The holding member has a function of defining the relative positions of the magnetic core 8 and the coil 9 and maintaining the positioning state. The holding member is disposed, for example, between the end face 91 of the winding portion 90 and the end core portions 5 and 6. The holding member disposed between the end face 91 of the winding portion 90 and the end core portions 5 and 6 is, for example, a frame-shaped member. The holding member is disposed, for example, between the inner peripheral surface of the winding portion 90 and the outer peripheral surface of the middle core portion 2. The holding member disposed between the inner peripheral surface of the winding portion 90 and the outer peripheral surface of the middle core portion 2 is, for example, a cylindrical member. The holding member disposed between the inner peripheral surface of the winding portion 90 and the outer peripheral surface of the middle core portion 2 is, for example, structured so that the unsolidified constituent resin of the molded resin portion can flow between the winding portion 90 and the middle core portion 2.

[0091] <Embodiment 6> A reactor of the sixth embodiment will be described with reference to Fig. 8. The reactor of the sixth embodiment is different from the reactor 7 of the fifth embodiment in the combination of the first core laminations 81 and the second core laminations 82. The reactor of the sixth embodiment has the same configuration as the reactor 7 of the fifth embodiment, except for the combination of the first core laminations 81 and the second core laminations 82. For convenience of explanation, Fig. 8 shows the reactor from a direction in which the first surface 111 shown in Fig. 1 can be seen. For convenience of explanation, Fig. 8 shows the winding portion 90 of the coil 9 in cross section.

[0092] The first core piece 81 of this example includes one first block portion 110 and three second block portions 120. One first block portion 110 is the same as the first block portion 110 of the core piece 1α of the first embodiment. In FIG. 8, for convenience of explanation, the reactor is shown from the direction in which the first surface 111 shown in FIG. 1 is visible, but in the first block portion 110, the first portion 11 and the second portion 12 overlap in the direction along the height of the first block portion 110. The first block portion 110 is the end core portion 5. Of the three second block portions 120, the middle core portion 21 arranged inside the winding portion 90 has a shorter length along the first direction D1 than the side core portions 3 and 4 arranged outside the winding portion 90. The first core piece 81 of this example has an E-shaped shape in which the above-mentioned length of the middle core portion 21 is short. Each second block portion 120 is composed of the second portion 12.

[0093] The second core piece 82 of this example has an end core portion 6 and a middle core portion 22. The second core piece 82 of this example has a T-shape composed of the end core portion 6 and the middle core portion 22. Both the end core portion 6 and the middle core portion 22 are composed of the first portion 11. The second core piece 82 of this example is composed only of the first portion 11 and does not have a second portion 12. The second core piece 82 of this example is an integral piece in which the end core portion 6 and the middle core portion 22 are integrally molded.

[0094] In this example, the magnetic core 8 has a θ-shape by combining the E-shaped first core piece 81 and the T-shaped second core piece 82.

[0095] In this example, the first core piece 81 has the first block portion 110 of the core piece 1α of embodiment 1, and the second core piece 82 is composed of the first portion 11, so that leakage magnetic flux from each end core portion 5, 6 can be suppressed, and deterioration of loss can be suppressed.

[0096] <Embodiment 7> A reactor of the seventh embodiment will be described with reference to Fig. 9. The reactor of the seventh embodiment is different from the reactor 7 of the fifth embodiment and the reactor of the sixth embodiment in the combination of the first core laminations 81 and the second core laminations 82. The reactor of the seventh embodiment has the same configuration as the reactor 7 of the fifth embodiment except for the combination of the first core laminations 81 and the second core laminations 82. For convenience of explanation, Fig. 9 shows the reactor from a direction in which the first surface 111 shown in Fig. 1 can be seen. For convenience of explanation, Fig. 9 shows a winding portion 90 of the coil 9 in cross section.

[0097] The first core piece 81 of this example includes one first block portion 110 and three second block portions 120. One first block portion 110 is the same as the first block portion 110 of the core piece 1α of the first embodiment. In FIG. 9, for convenience of explanation, the reactor is shown from the direction in which the first surface 111 shown in FIG. 1 is visible, but in the first block portion 110, the first portion 11 and the second portion 12 overlap in the direction along the height of the first block portion 110. The first block portion 110 is the end core portion 5. Of the three second block portions 120, the middle core portion 21 arranged inside the winding portion 90 has a shorter length along the first direction D1 than the side core portions 3 and 4 arranged outside the winding portion 90. The first core piece 81 of this example has an E-shaped shape in which the middle core portion 21 has a shorter length.

[0098] The middle core portion 21 is composed of a first portion 11 and a second portion 12. The first portion 11 of the middle core portion 21 is an integral block body with no joint between it and the first portion 11 of the first block portion 110. The block body composed of the first portion 11 of the middle core portion 21 and the first portion 11 of the first block portion 110 has a T-shape. The second portion 12 of the middle core portion 21 is configured to cover the end face and the first surface of the first portion 11 of the middle core portion 21 and to be continuous with the second portion 12 of the first block portion 110. The side core portions 3 and 4 are composed of the second portion 12.

[0099] The second core laminations 82 of this example are the same as the second core laminations 82 of the sixth embodiment.

[0100] In this example, the magnetic core 8 has a θ-shape by combining the E-shaped first core piece 81 and the T-shaped second core piece 82.

[0101] In this example, the first block portion 110 constituting the end core portion 5 of the first core lamination 81 has the first portion 11, and the second core lamination 82 is also composed of the first portion 11, so that leakage magnetic flux from each end core portion 5, 6 can be suppressed, and deterioration of loss can be suppressed.

[0102] <Modification> Although not shown, the coil may have two winding parts. In this case, the magnetic core has two inner core parts and two outer core parts. The two inner core parts are provided so as to face the inner side of the winding part. The two outer core parts are provided so as to connect the end faces of the two inner core parts. The two outer core parts have a portion provided so as to face the end face of each winding part. The core piece constituting the magnetic core is, for example, a U-shaped block body. The U-shaped core piece is formed by joining a first block part and a second block part. The first block part is the outer core part, and the second block part is the inner core part. The first block part has a first part and a second part, and the first part is arranged within a predetermined height range of the first block part.

[0103] <Embodiment 8> <Converter / power conversion device> The above-mentioned reactor 7 can be used for applications that satisfy the following energization conditions. The energization conditions are, for example, a maximum DC current of about 100 A to 1000 A, an average voltage of about 100 V to 1000 V, and an operating frequency of about 5 kHz to 100 kHz. The above-mentioned reactor 7 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 this converter.

[0104] 10, a vehicle 1200 such as a hybrid vehicle or an electric vehicle includes a main battery 1210, a power conversion device 1100 connected to the main battery 1210, and a motor 1220 that is driven by power supplied from the main battery 1210 and used for traveling. The motor 1220 is typically a three-phase AC motor, which drives wheels 1250 during traveling and functions as a generator during regeneration. In the case of a hybrid vehicle, the vehicle 1200 includes an engine 1300 in addition to the motor 1220. In FIG. 10, the charging point of the vehicle 1200 is an inlet, but a form including a plug may also be used.

[0105] The power conversion device 1100 includes a converter 1110 connected to a main battery 1210, and an inverter 1120 connected to the converter 1110 and performing mutual conversion between direct current and alternating current. The converter 1110 shown in this example boosts the input voltage of the main battery 1210, which is about 200V to 300V, to about 400V to 700V when the vehicle 1200 is running, and supplies power to the inverter 1120. During regeneration, the converter 1110 lowers the input voltage output from the motor 1220 via the inverter 1120 to a direct current voltage suitable for the main battery 1210, and charges the main battery 1210. The input voltage is a direct current voltage. When the vehicle 1200 is running, the inverter 1120 converts the DC boosted by the converter 1110 into a predetermined AC and supplies it to the motor 1220. During regeneration, the inverter 1120 converts the AC output from the motor 1220 into DC and outputs it to the converter 1110.

[0106] As shown in FIG. 11, the converter 1110 includes a plurality of switching elements 1111, a drive circuit 1112 that controls the operation of the switching elements 1111, and a reactor 1115, and converts the input voltage by repeatedly switching the switching elements 1111 on and off. The conversion of the input voltage means stepping up and down the voltage here. The switching elements 1111 are power devices such as field effect transistors and insulated gate bipolar transistors. The reactor 1115 utilizes the properties of a coil that prevents changes in the current flowing through the circuit, and has the function of smoothing out changes when the current increases or decreases due to switching operations. The reactor 7 described above is included as the reactor 1115.

[0107] In addition to the converter 1110, the vehicle 1200 includes a power supply converter 1150 connected to the main battery 1210, and an auxiliary power converter 1160 connected to the sub-battery 1230 serving as a power source for the auxiliary devices 1240 and the main battery 1210 to convert the high voltage of the main battery 1210 to a low voltage. The converter 1110 typically performs DC-DC conversion, while the power supply converter 1150 and the auxiliary power converter 1160 perform AC-DC conversion. Some of the power supply converters 1150 perform DC-DC conversion. The reactors of the power supply converter 1150 and the auxiliary power converter 1160 may have the same configuration as the reactor 7 described above, and may be of a different size, shape, or the like, as appropriate. The reactor 7 described above may also be used as a converter that converts input power and that only boosts the voltage or only lowers the voltage.

[0108] [Test example] Reactors were fabricated using various core pieces each having a first portion made of a powder compact and a second portion made of a composite material compact, and the inductance and loss of the reactor were investigated.

[0109] In each sample in the test example, a magnetic core was used in which two core pieces of the same shape and size were combined. The shape of the magnetic core was the same as that of the magnetic core 8 shown in FIG. 6. Each core piece had one first block portion and three second block portions. The first block portion was arranged so as to face the end face of the winding portion of the coil. The three second block portions have side faces facing either the inner or outer surface of the winding portion, and are arranged so that the side faces face each other. Of the three second block portions, the middle core portion has a portion that is arranged inside the winding portion. Of the three second block portions, two side core portions are arranged so as to sandwich the middle core portion outside the winding portion.

[0110] In each core piece, the first block portion is formed by combining the first portion and the second portion. In each core piece, the second block portion is formed only of the second portion. In each sample, the powder compact forming the first portion is made of the same material. In each sample, the composite material compact forming the second portion is made of the same material.

[0111] In each test sample, coils of the same shape and size were used.

[0112] <Test Example 1> In test example 1, the first and second parts constituting the first block portion were stacked in a direction along the height of the first block portion, samples having different heights of the first part were prepared, and the effect of the height of the first part of the first block portion was investigated.

[0113] <Sample> Samples No. 1-1 to No. 1-6 were produced, each having a first block portion with a different height of the first portion. Samples No. 1-1 to No. 1-6 differ in the ratio H1 / H0 of the height H1 of the first portion to the height H0 of the first block portion. The ratio H1 / H0 of Sample No. 1-1 is 0.17. The ratio H1 / H0 of Sample No. 1-2 is 0.33. The ratio H1 / H0 of Sample No. 1-3 is 0.50. The ratio H1 / H0 of Sample No. 1-4 is 0.67. The ratio H1 / H0 of Sample No. 1-5 is 0.83. The ratio H1 / H0 of Sample No. 1-6 is 1.00.

[0114] In each of Sample No. 1-1 to Sample No. 1-6, the ratio T1 / T0 of the thickness T1 of the first portion to the thickness T0 of the first block portion is 1.00. In each of Sample No. 1-1 to Sample No. 1-6, the ratio W1 / W0 of the width W1 of the first portion to the width W0 of the first block portion is 1.00.

[0115] In sample No. 1-10, the first block portion is composed of only the second portion and does not include the first portion.

[0116] <Inductance> For each sample reactor, the inductance was determined when a direct current of 250 A was passed through the coil. For the inductance analysis, JMAG-Designer 22.0, a commercially available electromagnetic field analysis software made by JSOL Corporation, was used. The results are shown in Table 1. In Table 1, the results are shown as relative values, with the results for sample No. 1-10 taken as 100 percent.

[0117] ≪Loss≫ The loss when the reactor was driven was determined for each sample reactor. To analyze the loss, JMAG-Designer22.0, a commercially available electromagnetic field analysis software made by JSOL Corporation, was used. The reactor drive conditions were DC current 0A, input voltage 300V, output voltage 600V, and frequency 20kHz. Under these conditions, the loss in the coil and the total loss were determined. The total loss includes the loss in the coil, the loss in the magnetic core, and the loss in the case when the reactor is placed in the case. The results are shown in Table 1. In Table 1, the results for sample No. 1-10 are shown as relative values, with the results taken as 100 percent.

[0118] [Table 1]

[0119] As shown in Table 1, when the ratio H1 / H0 exceeds 0.50, the total loss is smaller than that of sample No. 1-10. When the ratio H1 / H0 exceeds 0.50, the first portion made of the powder compact is disposed over a relatively wide area of ​​the first block portion. It is believed that the relatively wide area of ​​the first portion made of the powder compact with high magnetic permeability suppresses leakage flux from the first block portion, thereby suppressing deterioration of loss.

[0120] As shown in Table 1, even if the ratio H1 / H0 increases, the rate of decrease in inductance is small. Although the powder compact is prone to magnetic saturation, since the first block portion is arranged to face the end face of the winding portion, it is considered that the effect of the powder compact arranged in this first block portion on magnetic saturation is relatively small. In other words, it is considered that the first block portion can maintain a high inductance even if the ratio H1 / H0 increases.

[0121] In the first block portion, it is required that the first portion and the second portion are well bonded to each other. If the ratio H1 / H0 is less than 1.00, the first portion and the second portion overlap in the direction along the height of the first block portion, and the first portion and the second portion are bonded to each other over a relatively large surface area. Therefore, if the ratio H1 / H0 is less than 1.00, it is considered that the first portion and the second portion can be well bonded to each other.

[0122] [Test Example 2] In test example 2, the first and second parts constituting the first block portion were stacked in a direction along the thickness of the first block portion to prepare samples having different thicknesses of the first part, and the effect of the thickness of the first part of the first block portion was investigated.

[0123] <Sample> Samples No. 2-1 to No. 2-5 were produced, each having a first block portion with a different thickness of the first portion. Samples No. 2-1 to No. 2-5 differ in the ratio T1 / T0 of the thickness T1 of the first portion to the thickness T0 of the first block portion. The ratio T1 / T0 of Sample No. 2-1 is 0.29. The ratio T1 / T0 of Sample No. 2-2 is 0.47. The ratio T1 / T0 of Sample No. 2-3 is 0.65. The ratio T1 / T0 of Sample No. 2-4 is 0.82. The ratio T1 / T0 of Sample No. 2-5 is 1.00.

[0124] In each of Samples No. 2-1 to No. 2-5, the ratio H1 / H0 of the height H1 of the first portion to the height H0 of the first block portion is 1.00. In each of Samples No. 2-1 to No. 2-5, the ratio W1 / W0 of the width W1 of the first portion to the width W0 of the first block portion is 1.00.

[0125] In sample No. 2-10, the first block portion is composed of only the second portion and does not include the first portion. Sample No. 2-10 is the same as sample No. 1-10.

[0126] <Inductance> For each sample reactor, the inductance was determined when a direct current of 250 A was applied to the coil in the same manner as in Test Example 1. The results are shown in Table 2. In Table 2, the results are shown as relative values, with the result of sample No. 2-10 being set at 100 percent.

[0127] ≪Loss≫ For each sample reactor, the loss when the reactor was driven was determined in the same manner as in Test Example 1. The results are shown in Table 2. In Table 2, the results are shown as relative values ​​with the result of sample No. 2-10 set to 100 percent.

[0128] [Table 2]

[0129] As shown in Table 2, when the ratio T1 / T0 exceeds 0.47, the total loss is smaller than that of sample No. 2-10. When the ratio T1 / T0 exceeds 0.47, the first portion made of the powder compact is disposed over a relatively wide area of ​​the first block portion. It is considered that the leakage magnetic flux from the first block portion can be suppressed by disposing the first portion made of the powder compact having high magnetic permeability over a relatively wide area, thereby suppressing the deterioration of loss.

[0130] As shown in Table 2, even if the ratio T1 / T0 increases, the rate of decrease in inductance is small. Although the powder compact is prone to magnetic saturation, since the first block portion is arranged to face the end face of the winding portion, it is considered that the effect of the powder compact arranged in this first block portion on magnetic saturation is relatively small. In other words, it is considered that the first block portion can maintain a high inductance even if the ratio T1 / T0 increases.

[0131] Looking at Test Example 1 and Test Example 2 as a whole, it is considered that when the ratio H1 / H0 is greater than 0.50 and less than 1.00, and the ratio T1 / T0 is greater than 0.47, the loss can be reduced and the first portion and the second portion can be joined to each other satisfactorily.

[0132] [Test Example 3] In test example 3, the first and second portions constituting the first block portion were overlapped in a direction along the width of the first block portion to prepare samples having different widths of the first portion, and the effect of the width of the first portion of the first block portion was investigated.

[0133] <Sample> Samples No. 3-1 to No. 3-6 were produced, each having a first block portion with a different width of the first portion. Samples No. 3-1 to No. 3-6 differ in the ratio W1 / W0 of the width W1 of the first portion to the width W0 of the first block portion. The ratio W1 / W0 of Sample No. 3-1 is 0.33. The ratio W1 / W0 of Sample No. 3-2 is 0.47. The ratio W1 / W0 of Sample No. 3-3 is 0.60. The ratio W1 / W0 of Sample No. 3-4 is 0.73. The ratio W1 / W0 of Sample No. 3-5 is 0.87. The ratio W1 / W0 of Sample No. 3-6 is 1.00.

[0134] In each of Samples No. 3-1 to No. 3-6, the ratio H1 / H0 of the height H1 of the first portion to the height H0 of the first block portion is 1.00.In each of Samples No. 3-1 to No. 3-6, the ratio T1 / T0 of the thickness T1 of the first portion to the thickness T0 of the first block portion is 1.00.

[0135] In sample No. 3-10, the first block portion is composed of only the second portion and does not include the first portion. Sample No. 3-10 is the same as sample No. 1-10.

[0136] <Inductance> For each sample reactor, the inductance was determined when a direct current of 250 A was applied to the coil in the same manner as in Test Example 1. The results are shown in Table 3. In Table 3, the results are shown as relative values, with the result of sample No. 3-10 being set at 100 percent.

[0137] ≪Loss≫ For each sample reactor, the loss when the reactor was driven was determined in the same manner as in Test Example 1. The results are shown in Table 3. In Table 3, the results are shown as relative values ​​with the result of sample No. 3-10 set to 100 percent.

[0138] [Table 3]

[0139] As shown in Table 3, all of Sample No. 3-1 to Sample No. 3-6 have smaller total losses than Sample No. 3-10. Comparing Sample No. 3-1 to Sample No. 3-6, the larger the ratio W1 / W0, the smaller the coil loss and total loss. The larger the ratio W1 / W0, the more the first portion made of the powder compact is disposed over a relatively wide area of ​​the first block portion. It is believed that by disposing the first portion made of the powder compact with high magnetic permeability over a relatively wide area, leakage magnetic flux from the first block portion can be suppressed, thereby suppressing the deterioration of loss.

[0140] As shown in Table 3, even if the ratio W1 / W0 increases, the rate of decrease in inductance is small. Although the powder compact is prone to magnetic saturation, since the first block portion is arranged to face the end face of the winding portion, it is considered that the effect of the powder compact arranged in this first block portion on magnetic saturation is relatively small. In other words, it is considered that the first block portion can maintain a high inductance even if the ratio W1 / W0 increases.

[0141] Looking at Test Examples 1 and 3 as a whole, it is considered that when the ratio H1 / H0 is greater than 0.50 and less than 1.00, and the ratio W1 / W0 is 0.30 or more, the loss can be reduced and the first portion and the second portion can be joined to each other satisfactorily. [Explanation of symbols]

[0142] 1α, 1β, 1γ, 1δ core pieces 11 First part 12 Second part, 12A connection part, 12B collar part 110 First Block Section 111 Front page 112 Second side 113 Outer end face 115 Side 120 Second Block Section 125 Side 2,21,22 Middle Core Section 3,31,32 Side core part 4,41,42 Side core part 5 End core section 6 End core section 2g Gap 7 Reactor 8 Magnetic Core 81 First core piece 82 Second core piece 9 Coil 90 Winding section 91 End face 92 Inner surface 93 External surface D1 first direction, D2 second direction, D3 third direction H0,H1 height T0,T1 thickness W0,W1 width 1100 Power conversion device, 1110 Converter, 1111 Switching element 1112 Drive circuit, 1115 Reactor, 1120 Inverter 1150 Converter for power supply device, 1160 Converter for auxiliary power supply 1200 vehicle, 1210 main battery, 1220 motor 1230 Sub-battery, 1240 Auxiliary equipment, 1250 Wheels, 1300 Engine

Claims

1. A core piece for constituting a magnetic core arranged inside and outside a coil, A first block portion arranged to face an end surface of the coil; a plurality of second block portions each having a side surface facing either an inner surface or an outer surface of the coil, the side surfaces being arranged to face each other; The first block portion is A first portion constituted by a powder compact of soft magnetic powder; A 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 and the second portion overlap in a direction along a height of the first block portion, A ratio of a height of the first portion to a height of the first block portion is greater than 0.5 and less than 1; Each of the height of the first block portion and the height of the first portion is a length along a direction perpendicular to both a direction along the axis of the coil and a direction in which the plurality of second block portions are arranged. Core piece.

2. The core piece according to claim 1 , wherein the plurality of second block portions are formed of the molded body of the composite material so as to be continuous with the second portion.

3. the first block portion has a first surface and a second surface facing each other in a direction along the height of the first block portion, the first portion comprises the first surface; The core piece according to claim 1 or claim 2, wherein the second portion comprises the second surface.

4. the first portion and the second portion overlap in a direction along a thickness of the first block portion, a ratio of a thickness of the first portion to a thickness of the first block portion is 0.6 or more; The core piece according to claim 1 or 2, wherein each of the thickness of the first block portion and the thickness of the first portion is a length along the axis of the coil.

5. The first block portion has an outer end surface facing outward in a direction along the axis of the coil, The core piece according to claim 1 or claim 2, wherein the first portion comprises the outer end surface.

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

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

8. A converter comprising: Power conversion equipment.

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