Core components, reactors, converters, and power conversion devices

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 Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

[0005] One of the purposes of this disclosure is to provide a core piece that enables the manufacture of a reactor having high inductance and low loss even under high-current operating conditions, by having a first part and a second part made of different materials that are well joined together. Another purpose of this disclosure is to provide a reactor equipped with the above core piece. Another purpose of this disclosure is to provide a converter equipped with the above reactor. Another purpose of this disclosure is to provide a power conversion device equipped with the above converter. [Means for solving the problem]

[0006] The core piece of the present disclosure is a core piece for constituting a magnetic core disposed inside or outside a coil, and comprises a first block portion disposed so as to face the end face of the coil, and a plurality of second block portions having sides facing either the inner or outer surface of the coil, and the sides facing each other. The first block portion comprises a first part made of a compacted molded body of soft magnetic powder, and a second part made 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 overlap in a direction along the height of the first block portion. The ratio of the height of the first part 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 part are lengths along directions perpendicular to both the direction along the axis of the coil and the direction in which the plurality of second block portions are aligned. [Effects of the Invention]

[0007] The core piece of this disclosure consists of a first portion and a second portion made of different materials that are well joined together, enabling the manufacture of a reactor that maintains high inductance and low loss even under high-current operating conditions. [Brief explanation of the drawing]

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

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

[0010] (1) A core piece according to the embodiment of the present disclosure is a core piece for constituting a magnetic core disposed inside or outside a coil, comprising: a first block portion disposed so as to face the end face of the coil; and a plurality of second block portions having sides facing either the inner or outer surface of the coil, and arranged such that the sides face each other. The first block portion comprises a first part made of a compacted molded body of soft magnetic powder and a second part made 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 overlap in a direction along the height of the first block portion. The ratio of the height of the first part 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 part are lengths along directions perpendicular to both the direction along the axis of the coil and the direction in which the plurality of second block portions are aligned.

[0011] The above core piece makes it possible to manufacture reactors that maintain high inductance and low loss even under high-current operating environments. The compacted material has higher magnetic permeability compared to the composite material molded material. When the first part, composed of the compacted material, is positioned within a predetermined height range of the first block, leakage flux from the first block can be suppressed, thereby preventing deterioration of losses. On the other hand, compacted material is prone to magnetic saturation. Since the first block is positioned facing the end face of the coil, in other words, the first block is positioned outside the coil, the influence of the compacted material positioned in the first block on magnetic saturation is relatively small, and high inductance can be maintained. The first part and the second part overlap in the direction along the height of the first block, so they are joined well over a relatively large surface area.

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

[0013] If the second block portion is composed of a molded body of a composite material, the gap provided in the middle of the second block portion may be small. For example, if the gap of the second block portion disposed in the coil is small, the leakage magnetic flux from the gap is small, and the deterioration of the loss can be suppressed. Since the molded body of the composite material is configured such 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 joined to each other. When the first block portion and the second block portion are firmly joined to each other, it is easy to handle the first block portion and the second block portion as an integral body.

[0014] (3) In the core piece according to the above (1) or (2), the first block portion may include 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 include the first surface, and the second portion may include the second surface.

[0015] The core piece of the above (3) is easy to arrange the first portion and the second portion in the height direction of the first block portion.

[0016] (4) In the core piece according to any one of the above (1) to (3), the first portion and the second portion overlap in a direction along the thickness of the first block portion, and the ratio of the thickness of the first portion to the 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 the length along the axis of the coil.

[0017] If the first portion and the second portion overlap not only in the direction along the height of the first block portion but also in the direction along the thickness of the first block portion, they are well joined on a relatively large surface. If the ratio of the thickness is 0.6 or more, the leakage magnetic flux from the first block portion can be further suppressed, and the deterioration of the loss can be further suppressed.

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

[0019] The core piece described in (5) above is easy to arrange in the thickness direction of the first block, with the first and second parts positioned accordingly.

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

[0021] A reactor equipped with a magnetic core containing the above-mentioned core piece maintains high inductance and low loss even under high-current operating conditions.

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

[0023] Converters equipped with the above-mentioned reactor maintain high inductance and low losses even under high-current operating conditions.

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

[0025] The power conversion device equipped with the above converter maintains high inductance and low loss even in high-current operating environments.

[0026] [Details of the embodiments of this disclosure] Specific examples of embodiments of the present disclosure will be described below with reference to the drawings. Identical reference numerals in the drawings indicate identical parts. In each drawing, some parts of the configuration may be exaggerated or simplified for ease of explanation. The dimensional ratios of parts in the drawings may also differ from those of the actual parts. The present invention is not limited to these examples, but is shown in the claims, and all modifications within the meaning and scope equivalent to the claims are intended.

[0027] <Embodiment 1> ≪Core Piece≫ The core piece 1α of Embodiment 1 will be described with reference to Figures 1 and 2. The core piece 1α is a component of the reactor 7 (Figure 6), which will be described later. The core piece 1α constitutes a magnetic core 8 that is arranged inside and outside the coil 9 (Figures 6 and 7) of the reactor 7. The core piece 1α comprises 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 (Figures 6 and 7) of the coil 9. One of the features of the core piece 1α of Embodiment 1 is that the first block portion 110 comprises a first part 11 and a second part 12, and the first part 11 is arranged within a predetermined height range of the first block portion 110. The first part 11 is a part made by compaction. The second part 12 is a part made by a molded composite material. In the core piece 1α of Embodiment 1, the plurality of second block portions 120 also comprise a second part 12. The core piece 1α of Embodiment 1 is a single piece formed by integrally molding a first block portion 110 and a plurality of second block portions 120. Below, the materials of the first portion 11 and the second portion 12 will be described first, and then the configuration of the first block portion 110 and the second block portions 120 will be described in order. In each figure, cross-hatching is applied to the first portion 11 for clarity.

[0028] In the following explanation, we may use the terms first direction D1, second direction D2, and third direction D3. The first direction D1 is the direction along the axis of the winding portion 90 of the coil 9 (Figures 6 and 7). The direction along the axis of the winding portion 90 is also the direction along the axis of the second block portion 120. The second direction D2 is the direction in which the multiple second block portions 120 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 the following explanation, 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 section 11 is a region composed of a compacted body of soft magnetic powder. The compacted body is formed by pressure molding raw material powder containing soft magnetic powder. Compared to the composite material molded body described later, the compacted body can have a higher content of soft magnetic powder. A compacted body with a high content of soft magnetic powder has high magnetic permeability. The content of soft magnetic powder in the compacted body is, for example, more than 80% by volume, 85% or more by volume, 90% or more by volume, or 95% or more by volume, when the compacted body is considered as 100% by volume. The raw material powder may also contain a lubricant.

[0030] Soft magnetic powder is composed of, for example, particles of soft magnetic metal, coated particles, or particles of soft magnetic nonmetal. Coated particles consist of soft magnetic metal particles and an insulating coating provided on the outer circumference of the soft magnetic metal particles. Soft magnetic metals are, for example, pure iron or iron-based alloys. Iron-based alloys are, for example, Fe-Si alloys or Fe-Ni alloys. The insulating coating is, for example, a phosphate. Soft magnetic nonmetals are, for example, ferrite.

[0031] [Second part] The second region 12 is a region composed of a molded body of a composite material in which soft magnetic powder is dispersed in resin. The molded body of the 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 of soft magnetic powder in the resin. In particular, the composite material is easy to adjust to have a low content of soft magnetic powder, making it easy to lower the permeability. Although the molded body of the composite material has lower permeability compared to the compacted molded body, it is less prone to magnetic saturation under high-current operating environments and has low iron loss. The molded body of the composite material is easier to mold into complex shapes compared to the compacted molded body.

[0032] The soft magnetic powder constituting the molded composite material is the same as the soft magnetic powder constituting the compacted powder molded body described above. The content of soft magnetic powder in the molded composite material is, for example, 20% to 80% by volume, when the composite material is considered to be 100% by volume.

[0033] The resin constituting the molded composite material is, for example, a thermosetting resin or a thermoplastic resin. Thermosetting resins include, for example, epoxy resins, phenolic resins, silicone resins, or urethane resins. Thermoplastic resins include, for example, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT), polyamide (PA) resin, liquid crystal polymer (LCP), polyimide (PI) resin, or fluororesin. Polyamide resins include, for example, nylon 6, nylon 66, or nylon 9T. The resin content in the molded composite material is, for example, 20% to 80% by volume, when the composite material is considered to be 100% by volume.

[0034] The composite material may contain fillers in addition to the resin. The fillers contribute to improved heat dissipation. The fillers can be powders made of non-magnetic materials such as ceramics or carbon nanotubes. Ceramics are, for example, metallic or nonmetallic oxides, nitrides, or carbides. Examples of oxides are alumina, silica, or magnesium oxide. Examples of nitrides are silicon nitride, aluminum nitride, or boron nitride. An example of a carbide is silicon carbide.

[0035] [First Block Section] The first block section 110 is an area positioned to face the end face 91 (Figures 6 and 7) of the winding section 90 of the coil 9, which will be described later. The first block section 110 is sometimes referred to as the end core section 5.

[0036] The first block section 110 is positioned outside the winding section 90 to connect multiple second block sections 120. The shape of the first block section 110 can be any shape that connects multiple second block sections 120. In this example, the first block section 110 is a rectangular block.

[0037] The first block section 110 comprises a first part 11 and a second part 12. The first part 11 and the second part 12 are configured to overlap in a direction along the height of the first block section 110. The direction along the height of the first block section 110 is the third direction D3. The first block section 110 comprises a first surface 111 and a second surface 112 facing each other in the third direction D3. In this example, the first part 11 comprises the first surface 111, and the second part 12 comprises the second surface 112. In this example, the first part 11 is composed of a single block body comprising the first surface 111. In this example, the second part 12 is configured to cover the surface of the first part 11 opposite to the first surface 111. The second part 12 comprises the second surface 112 by covering the first part 11.

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

[0039] The ratio H1 / H0 of the height of the first part 11 to the height H0 of the first block part 110 is greater than 0.5 and less than 1. The height of the first block part 110 and the height of the first part 11 are both lengths along the third direction D3. As described above, powder compacted bodies have higher magnetic permeability compared to molded bodies made of composite materials. If the above ratio H1 / H0 is greater than 0.5, the first part 11, which is made of powder compacted body material, will be distributed over a relatively wide area of ​​the first block part 110. When the first part 11 is distributed over a relatively wide area, leakage flux from the first block part 110 can be suppressed, and the deterioration of losses can be suppressed.

[0040] As mentioned above, compacted molded bodies are prone to magnetic saturation. The first block portion 110 is positioned so as to face the end face 91 of the winding portion 90 (Figures 6 and 7), in other words, the first block portion 110 is positioned outside the winding portion 90. Therefore, the influence of the compacted molded body positioned in the first block portion 110 on magnetic saturation is relatively small. As a result, the first block portion 110 can maintain high inductance.

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

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

[0043] The second portion 12 of the first block portion 110 is connected to the 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 that protrudes from each second block portion 120. The multiple second block portions 120, which will be described later, are integrated by this second portion 12 of the first block portion 110. The height of the second portion 12 of the first block portion 110 changes according to the above 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 the 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. In this example, the first portion 11 is arranged 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 explained in Embodiment 3 with reference to Figure 4.

[0045] The first part 11 and the second part 12 of the first block section 110 may overlap in the direction along the width of the first block section 110. The direction along the width of the first block section 110 is the second direction D2. In this example, the first part 11 and the second part 12 of the first block section 110 do not overlap in the direction along the width of the first block section 110. In this example, the first part 11 is arranged across the entire width of the first block section 110. The ratio W1 / W0 of the width W1 of the first part 11 to the width W0 of the first block section 110 will be explained in Embodiment 4 with reference to Figure 5.

[0046] [Second Block Section] Each second block section 120 is a region having a side surface 125 that faces either the inner surface 92 or the outer surface 93 (Figure 7) of the winding section 90. Multiple second block sections 120 are arranged so that their side surfaces 125 face each other. Each second block section 120 has multiple side surfaces 125. In each second block section 120, it is sufficient that one of the multiple side surfaces 125 faces the side surface 125 of an adjacent second block section 120. A second block section 120 located inside the winding section 90 has a side surface 125 that faces the inner surface 92 of the winding section 90. A second block section 120 located inside the winding section 90 is sometimes called a middle core section 21. A second block section 120 located outside the winding section 90 has a side surface 125 that faces the outer surface 93 of the winding section 90. A second block section 120 located outside the winding section 90 is sometimes called a side core section 31, 41.

[0047] The three second block sections 120 are connected to the same plane of a single first block section 110 and extend in the same direction. In each figure, a dashed line is drawn at the boundary between the first block section 110 and each second block section 120.

[0048] Of the multiple second block sections 120, the middle core section 21 has a portion that is located inside the winding section 90 (Figures 6 and 7). The middle core section 21 is a portion that extends in a direction intersecting the first block section 110 and may have a portion that is located outside the winding section 90. In other words, the middle core section 21 may have a portion located inside the winding section 90 and a portion located outside the winding section 90. The shape of the middle core section 21 is roughly corresponding to the inner circumference shape of the winding section 90. In this example, the middle core section 21 is a rectangular block. The corners of the middle core section 21 are rounded to conform to the corners of the winding section 90.

[0049] Of the multiple second block sections 120, the two side core sections 31 and 41 are arranged outside the winding section 90 (Figures 6 and 7) alongside the middle core section 21. The two side core sections 31 and 41 are arranged so as to sandwich the middle core section 21 while maintaining a gap between them. The shape of each side core section 31 and 41 is not limited to the shape of the middle core section 21. In this example, each side core section 31 and 41 is a rectangular block. In this example, the shape and dimensions of the two side core sections 31 and 41 are identical. In this example, the length of each side core section 31 and 41 along the first direction D1 is longer than the length of the middle core section 21 along the first direction D1. The length of each side core section 31 and 41 along the first direction D1 may be the same as or shorter than the length of the middle core section 21 along the first direction D1. In this example, the length of each side core section 31, 41 along the second direction D2 is shorter than the length of the middle core section 21 along the second direction D2. The sum of the lengths of each side core section 31, 41 along the second direction D2 in this example is shorter than the length of the middle core section 21 along the second direction D2. The sum of the lengths of each side core section 31, 41 along the second direction D2 may be equal to or greater than the length of the middle core section 21 along the second direction D2. In this example, the length of each side core section 31, 41 along the third direction D3 is the same as the length of the middle core section 21 along the third direction D3. The length of each side core section 31, 41 along the third direction D3 may be shorter or longer than the length of the middle core section 21 along the third direction D3. The shapes and dimensions of the two side core sections 31, 41 may be different.

[0050] Each second block section 120 includes at least a second part 12. Each second block section 120 may include only the second part 12. At least one of the multiple second block sections 120 may include both a first part 11 and a second part 12.

[0051] The second portion 12 of each second block section 120 is provided to be continuous with, for example, the second portion 12 of the first block section 110. The second portion 12 of each second block section 120 is a molded product that has no joint with, for example, the second portion 12 of the first block section 110. In this example, each second block section 120 consists only of 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 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 molded bodies of different composite materials. 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 different composite materials. Among the multiple second block portions 120, the second portion 12 of the middle core portion 21 located inside the winding portion 90 and the second portion 12 of the side core portions 31, 41 located outside the winding portion 90 may be made of different composite materials. 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 the same composite material. For example, the portion located inside the winding portion 90 (Figures 6 and 7) and the portion located outside the winding portion 90 may be made of molded composite materials of different materials.

[0053] Different composite materials are those in which at least some of the constituent materials differ. Different constituent materials include different types of soft magnetic powder and different types of resin. Different types of soft magnetic powder means, for example, that the composition of the soft magnetic powder differs. Different constituent material content means that the content of soft magnetic powder in the resin differs.

[0054] If the second block portion 120 includes the first portion 11, this 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 Figure 9.

[0055] The core piece 1α in this example comprises one first block portion 110 and three second block portions 120. The core piece 1α in this example has an E-shape composed of one first block portion 110 and three second block portions 120.

[0056] ≪Method for manufacturing core pieces≫ The core piece 1α described above is manufactured, for example, by performing the following first, second, and third steps. The first, second, and third steps are performed in order.

[0057] [First step] In the first step, a mold and a partial core piece are prepared. The mold comprises 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 the first space and is arranged side by side with each other. The partial core piece is a compacted molded body 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, a partial core piece is placed in a portion of the first space. The remainder of the first space is empty except for the space in which the partial core piece is placed.

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

[0060] <Embodiment 2> Referring to Figure 3, the core piece 1β of Embodiment 2 will be described. The core piece 1β of Embodiment 2 differs from the core piece 1α of Embodiment 1 in that the overlapping portion between the first portion 11 and the second portion 12 in the first block portion 110 is different. Except for the overlapping portion, the core piece 1β of Embodiment 2 has the same configuration as the core piece 1α of Embodiment 1.

[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 in this example does not have a first surface 111 and a second surface 112 of the first block portion 110. The first portion 11 of the first block portion 110 in this example is composed of a single block body that includes 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 this example, the ratio H1 / H0 of the height of the first part 11 to the height H0 of the first block part 110 is greater than 0.5 and less than 1. If the above ratio H1 / H0 is greater than 0.5, regardless of where the first part 11 is located in the direction along the height of the first block part 110, leakage flux from the first block part 110 can be suppressed, and deterioration of losses can be suppressed.

[0063] When the first part 11 is positioned between the second part 12, the first part 11 and the second part 12 are joined to each other more effectively. In this example, the entire surfaces of the two faces of the first part 11 facing the third direction D3 are joined to the second part 12.

[0064] <Embodiment 3> Referring to Figure 4, the core piece 1γ of Embodiment 3 will be described. The core piece 1γ of Embodiment 3 differs from the core piece 1α of Embodiment 1 in that the thickness T1 of the first portion 11 of the first block portion 110 is different. 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.

[0066] The second portion 12 of the first block portion 110 in this example comprises a connecting portion 12A and a flange portion 12B. The connecting portion 12A is a plate-shaped member provided to connect a plurality of second block portions 120. Each second block portion 120 is connected to the same plane of the connecting portion 12A. A part of the connecting portion 12A overlaps the first portion 11 in a direction along the thickness of the first block portion 110. The flange portion 12B is a plate-shaped member provided to protrude from the connecting portion 12A along the first direction D1. The flange portion 12B overlaps 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 part 11 to the thickness T0 of the first block part 110 is, for example, 0.6 or more. The thickness T0 of the first block part 110 includes the thickness of the connecting part 12A and the protruding length of the flange part 12B. The thickness of the connecting part 12A is the length obtained by subtracting the thickness T1 from the thickness T0 shown in Figure 4. The thickness of the connecting part 12A may be thin, like a thin film. The dashed line shown in Figure 4 indicates the boundary between the connecting part 12A and the flange part 12B. The thickness of the connecting part 12A is the length between the dashed line and the dashed line shown in Figure 4. If the above ratio T1 / T0 is 0.6 or more, the first part 11, which is made of compacted powder, will be arranged over a relatively wide area of ​​the first block part 110. When the first part 11 is arranged over a relatively wide area, leakage magnetic flux from the first block part 110 can be suppressed, and the deterioration of losses can be suppressed.

[0068] The above 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 above ratio T1 / T0 is 1, as shown in Figure 1, the first portion 11 is arranged over the entire thickness of the first block portion 110.

[0069] The above ratio T1 / T0 may be less than 1. If the above ratio T1 / T0 is less than 1, the first part 11 and the second part 12 will be joined over a relatively large surface area. If the above ratio T1 / T0 is less than 1, the first part 11 and the second part 12 will be joined to each other well.

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

[0071] <Embodiment 4> Referring to Figure 5, the core piece 1δ of Embodiment 4 will be described. The core piece 1δ of Embodiment 4 differs from the core piece 1α of Embodiment 1 in that the width W1 of the first portion 11 of the first block portion 110 is different. 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. In Figure 5, for the sake of explanation, the core piece 1δ is shown from a different direction than in Figure 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 have a side surface 115. The second portion 12 covers the side surface of the first portion 11 and thus comprises 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 part 11 to the width W0 of the first block part 110 is, for example, 0.3 or more. In this example, the corners of the first part 11 are rounded. In this case, the width W1 of the first part 11 is the widest width. If the above ratio W1 / W0 is 0.3 or more, the first part 11, which is made of compacted powder, will be arranged over a relatively wide area of ​​the first block part 110. When the first part 11 is arranged over a relatively wide area, leakage magnetic flux from the first block part 110 can be suppressed, and the deterioration of losses can be suppressed.

[0074] The above 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 above ratio W1 / W0 is 1, as shown in Figure 1, the first part 11 is arranged over the entire width of the first block part 110.

[0075] The above ratio W1 / W0 may be less than 1. If the above ratio W1 / W0 is less than 1, the first part 11 and the second part 12 will be joined over a relatively large surface area. If the above ratio W1 / W0 is less than 1, the first part 11 and the second part 12 will be joined to each other well.

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

[0077] <Embodiment 5> Reactor The reactor 7 of Embodiment 5 will be described with reference to Figures 6 and 7. The reactor 7 comprises a magnetic core 8 and a coil 9. The magnetic core 8 is composed of a set of a first core piece 81 and a second core piece 82. The first core piece 81 and the second core piece 82 are divided pieces that separate the magnetic core 8 in a first direction D1. The coil 9 is located in a part of the magnetic core 8. One of the features of the reactor 7 of Embodiment 5 is that at least one of the first core piece 81 and the second core piece 82 is the core piece 1α of Embodiment 1. At least one of the first core piece 81 and the second core piece 82 may be the core piece 1β of Embodiment 2, the core piece 1γ of Embodiment 3, or the core piece 1δ of Embodiment 4. In this example, both the first core piece 81 and the second core piece 82 are the core piece 1α of Embodiment 1. The first core piece 81 and the second core piece 82 are symmetrical with respect to an intermediate position in the magnetic core 8 in the first direction D1.

[0078] [Magnetic core] The magnetic core 8 is a magnetic element that forms an annular magnetic path by exciting the coil 9. In this example, the magnetic core 8 is configured in a θ shape as a whole by combining a first core piece 81 and a second core piece 82.

[0079] The magnetic core 8 comprises a middle core portion 2, two side core portions 3 and 4, and two end core portions 5 and 6. In Figures 6 and 7, dashed lines are shown at the boundary between the middle core portion 21 and the end core portion 5, and at the boundary between the side core portions 3 and 4 and the end core portion 5.

[0080] The middle core portion 2 has a portion that is located inside the winding portion 90 of the coil 9, which will be described later. In this example, the middle core portion 2 consists of the middle core portion 21 of the first core piece 81, the middle core portion 22 of the second core piece 82, and a gap 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 lengths of the middle core portions 21 and 22 along the second direction D2 are the same. The lengths of the middle core portions 21 and 22 along the third direction D3 are the same. 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. Providing a gap 2g makes it easier to adjust the inductance of the reactor 7. For example, a gap material (not shown) is placed in the gap 2g. Known materials can be used as the gap material. The constituent material of the gap material is, for example, non-magnetic ceramics or resin. The gap 2g may also be an air gap in which no gap material is placed. If the reactor 7 includes a molded resin part as described later, the gap 2g may be filled with the resin that constitutes the molded resin part. In this case, the resin that constitutes the molded resin part becomes the gap material.

[0081] The length of the middle core portion 2 along the first direction D1 is equal to or greater than the length of the winding portion 90 along the first direction D1. In this example, the length of the middle core portion 2 along the first direction D1 is slightly longer than the length of the winding portion 90 along the first direction D1. In other words, the middle core portion 2 comprises a portion located inside the winding portion 90 and a portion located outside the winding portion 90. Both ends of the middle core portion 2 are located outside the winding portion 90.

[0082] The side core portion 3 is composed of the side core portion 31 of the first core piece 81 and the 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, there is no gap 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 the side core portion 41 of the first core piece 81 and the 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, there is no gap 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] The magnetic core 8 is formed by the connection of one middle core section 2, two side core sections 3 and 4, and two end core sections 5 and 6. When the coil 9, described later, is energized, magnetic flux flows, forming a closed magnetic path. As shown by the dashed arrows in Figure 7, the magnetic flux flows from the middle core section 2 to the end core section 5, from the end core section 5 to each of the two side core sections 3 and 4, from each side core section 3 and 4 to the end core section 6, and from the end core section 6 to the middle core section 2.

[0085] In this example, since both the first core piece 81 and the second core piece 82 are core pieces 1α of Embodiment 1, leakage flux from each end core portion 5, 6 can be suppressed, and the deterioration of losses can be suppressed.

[0086] 〔coil〕 The coil 9 comprises at least one winding section 90. The coil 9 in this example comprises one winding section 90. The winding section 90 is constructed by winding a single wire spirally. Both ends of the wire are drawn out from each end of the winding section 90. Terminal fittings (not shown) are attached to both ends of the wire drawn out from the winding section 90. External devices (not shown) are connected to the terminal fittings. In Figures 5 and 6, only the winding section 90 is shown, and the ends of the wire are omitted.

[0087] A known winding can be used for the winding. The winding in this example is a coated flat wire consisting of a conductor wire with an insulating coating. The conductor wire is made of, for example, a copper flat wire. The insulating coating is made of, for example, enamel. The winding section 90 in this example is an edgewise coil formed by winding the coated flat wire edgewise.

[0088] The winding portion 90 has a rectangular tubular shape. That is, the end face 91 of the winding portion 90 in this example has a rectangular frame shape. The winding portion 90 has an inner surface 92 and an outer surface 93. The inner surface 92 faces the middle core portion 2. There is a gap between the inner surface 92 and the outer surface of the middle core portion 2. If the reactor 7 has a molded resin portion (not shown), this gap is filled with the resin that constitutes the molded resin portion. The outer surface 93 faces the side core portions 3 and 4. The end face 91 faces the end core portions 5 and 6. The corners of the winding portion 90 in this example are rounded. When the winding portion 90 has a rectangular tubular shape, the contact area between the winding portion 90 and the object to be installed tends to be larger compared to when the winding portion is cylindrical with the same cross-sectional area. A larger contact area between the winding portion 90 and the object to be installed improves the heat dissipation of the reactor 7. A larger contact area between the winding section 90 and the object to be installed makes it easier to stabilize the installation of the winding section 90 on the object.

[0089] 〔others〕 The reactor 7 may include a molded resin portion, although not shown in the figures. The molded resin portion covers at least a part of the magnetic core 8. The molded resin portion has the function of protecting the magnetic core 8 from the external environment. The molded resin portion may further cover the coil 9. In other words, the molded resin portion is provided so as to cover at least a part of the assembly of the magnetic core 8 and the coil 9. The molded resin portion integrates the magnetic core 8 and the coil 9 into a single unit. A part of the outer circumferential surface of the magnetic core 8, or at least a part of the outer circumferential surface of the coil 9, may be exposed from the molded resin portion. If the molded resin portion is provided between the magnetic core 8 and the coil 9, insulation between the magnetic core 8 and the coil 9 is easily ensured. If the molded resin portion is provided between the middle core portion 21 of the first core piece 81 and the middle core portion 22 of the second core piece 82, the molded resin portion provided between them functions as a gap material for the magnetic core 8. The resin constituting the molded resin portion is, for example, a resin similar to the resin of the composite material described above. The constituent materials of the molded resin portion may contain the fillers described above, similar to the composite materials.

[0090] The reactor 7 may include a retaining member, although it is not shown in the diagram. The retaining member is positioned between the magnetic core 8 and the coil 9 and has the function of ensuring electrical insulation between the magnetic core 8 and the coil 9. The retaining member defines the relative positions of the magnetic core 8 and the coil 9 and has the function of maintaining the positioning state. The retaining member is positioned, for example, between the end face 91 of the winding portion 90 and the end core portions 5 and 6. The retaining member positioned between the end face 91 of the winding portion 90 and the end core portions 5 and 6 is, for example, a frame-shaped member. The retaining member is positioned, for example, between the inner circumferential surface of the winding portion 90 and the outer circumferential surface of the middle core portion 2. The retaining member positioned between the inner circumferential surface of the winding portion 90 and the outer circumferential surface of the middle core portion 2 is, for example, a cylindrical member. The retaining member positioned between the inner circumferential surface of the winding portion 90 and the outer circumferential surface of the middle core portion 2 has a structure that allows the unsolidified constituent resin of the molded resin portion to flow between the winding portion 90 and the middle core portion 2.

[0091] <Embodiment 6> The reactor of Embodiment 6 will be described with reference to Figure 8. The reactor of Embodiment 6 differs from the reactor 7 of Embodiment 5 in the combination of the first core piece 81 and the second core piece 82. The reactor of Embodiment 6 has the same configuration as the reactor 7 of Embodiment 5, except for the combination of the first core piece 81 and the second core piece 82. In Figure 8, for the sake of explanation, the reactor is shown from a direction in which the first surface 111 shown in Figure 1 is visible. In Figure 8, for the sake of explanation, the winding portion 90 of the coil 9 is shown in cross-section.

[0092] The first core piece 81 in this example comprises one first block portion 110 and three second block portions 120. The one first block portion 110 is the same as the first block portion 110 of the core piece 1α in Embodiment 1. In Figure 8, for the sake of explanation, the reactor is shown from the direction in which the first surface 111 shown in Figure 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, which is located inside the winding portion 90, has a shorter length along the first direction D1 than the side core portions 3 and 4, which are located outside the winding portion 90. The first core piece 81 in this example has an E-shaped form due to the shorter length of the middle core portion 21. Each second block portion 120 is composed of a second portion 12.

[0093] The second core piece 82 in this example comprises an end core portion 6 and a middle core portion 22. The second core piece 82 in 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 in this example is composed only of the first portion 11 and does not have a second portion 12. The second core piece 82 in this example is a single 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-shaped form when the E-shaped first core piece 81 and the T-shaped second core piece 82 are combined.

[0095] In this example, since the first core piece 81 is comprised of 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, leakage flux from each end core portion 5, 6 can be suppressed, and deterioration of losses can be suppressed.

[0096] <Embodiment 7> The reactor of Embodiment 7 will be described with reference to Figure 9. The reactor of Embodiment 7 differs from the reactor 7 of Embodiment 5 and the reactor of Embodiment 6 in the combination of the first core piece 81 and the second core piece 82. The reactor of Embodiment 7 has the same configuration as the reactor 7 of Embodiment 5, except for the combination of the first core piece 81 and the second core piece 82. In Figure 9, for the sake of explanation, the reactor is shown from a direction where the first surface 111 shown in Figure 1 is visible. In Figure 9, for the sake of explanation, the winding portion 90 of the coil 9 is shown in cross-section.

[0097] The first core piece 81 in this example comprises one first block portion 110 and three second block portions 120. The one first block portion 110 is the same as the first block portion 110 of the core piece 1α in Embodiment 1. In Figure 9, for the sake of explanation, the reactor is shown from the direction in which the first surface 111 shown in Figure 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, which is located inside the winding portion 90, has a shorter length along the first direction D1 than the side core portions 3 and 4, which are located outside the winding portion 90. The first core piece 81 in this example has an E-shaped form in which the middle core portion 21 has the aforementioned shorter length.

[0098] The middle core section 21 is composed of a first section 11 and a second section 12. The first section 11 of the middle core section 21 is a single, seamless block body with no joints between it and the first section 11 of the first block section 110. The block body composed of the first section 11 of the middle core section 21 and the first section 11 of the first block section 110 has a T-shape. The second section 12 of the middle core section 21 covers the end face and first face of the first section 11 of the middle core section 21 and is configured to be continuous with the second section 12 of the first block section 110. The side core sections 3 and 4 are composed of the second section 12.

[0099] The second core piece 82 in this example is the same as the second core piece 82 in Embodiment 6.

[0100] In this example, the magnetic core 8 has a θ-shaped form when the E-shaped first core piece 81 and the T-shaped second core piece 82 are combined.

[0101] In this example, the first block portion 110 of the first core piece 81 that constitutes the end core portion 5 is equipped with the first portion 11, and the second core piece 82 is composed of the first portion 11. Therefore, leakage flux from each end core portion 5, 6 can be suppressed, and the deterioration of losses can be suppressed.

[0102] <Variation> Although not shown, the coil may have two winding sections. In this case, the magnetic core comprises two inner core sections and two outer core sections. The two inner core sections are provided so as to face the inner surfaces of the winding sections. The two outer core sections are provided so as to connect the end faces of the two inner core sections. The two outer core sections have portions provided so as to face the end faces of each winding section. The core pieces constituting the magnetic core are, for example, made up of U-shaped blocks. The U-shaped core piece is made up of a first block section and a second block section joined together. The first block section is the outer core section, and the second block section is the inner core section. The first block section comprises a first portion and a second portion, with the first portion positioned within a predetermined height range of the first block section.

[0103] <Embodiment 8> <<Converters / Power Conversion Devices>> The reactor 7 described above can be used for applications that meet the following energizing conditions. These conditions include, for example, a maximum DC current of approximately 100A to 1000A, an average voltage of approximately 100V to 1000V, and an operating frequency of approximately 5kHz to 100kHz. The reactor 7 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 such a converter.

[0104] A vehicle 1200, such as a hybrid or electric vehicle, includes a main battery 1210, a power converter 1100 connected to the main battery 1210, and a motor 1220 that is driven by power supplied from the main battery 1210 and used for propulsion, as shown in Figure 10. The motor 1220 is typically a three-phase AC motor, which drives the wheels 1250 during driving and functions as a generator during regenerative braking. In the case of a hybrid vehicle, the vehicle 1200 is equipped with an engine 1300 in addition to the motor 1220. In Figure 10, the charging point of the vehicle 1200 is an inlet, but it may also be equipped with a plug.

[0105] The power converter 1100 includes a converter 1110 connected to the main battery 1210 and an inverter 1120 connected to the converter 1110 that performs mutual conversion between DC and AC. In this example, the converter 1110 boosts the input voltage of the main battery 1210, which is approximately 200V to 300V, to approximately 400V to 700V when the vehicle 1200 is running, and supplies power to the inverter 1120. During regeneration, the converter 1110 steps down the input voltage output from the motor 1220 via the inverter 1120 to a DC voltage suitable for the main battery 1210, thereby charging the main battery 1210. The input voltage is a DC voltage. When the vehicle 1200 is running, the inverter 1120 converts the DC voltage boosted by the converter 1110 into a predetermined AC voltage and supplies power to the motor 1220. During regeneration, it converts the AC output from the motor 1220 into DC voltage and outputs it to the converter 1110.

[0106] As shown in Figure 11, the converter 1110 comprises a plurality of switching elements 1111, a drive circuit 1112 that controls the operation of the switching elements 1111, and a reactor 1115, and converts the input voltage by repeatedly switching ON / OFF. In this case, the input voltage conversion is step-up or step-down. Power devices such as field-effect transistors and insulated-gate bipolar transistors are used as switching elements 1111. The reactor 1115 utilizes the property of a coil that tries to oppose changes in the current that is about to flow through the circuit, and has the function of smoothing the change when the current tries to increase or decrease due to the switching operation. The reactor 1115 is the reactor 7 described above.

[0107] 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 the power source for the auxiliary equipment 1240, and which converts the high voltage of the main battery 1210 to low voltage. Converter 1110 typically performs DC-DC conversion, while 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 configuration as the reactor 7 described above, and reactors with appropriately changed size and shape can be used. Furthermore, the reactor 7 described above can also be used in converters that convert input power, such as converters that only perform boosting or converters that only perform step-down.

[0108] [Example Test] Reactors were fabricated using various core pieces, each consisting of a first part made of compacted powder and a second part made of a composite material, and the inductance and losses of these reactors were investigated.

[0109] Each sample in the test examples used a magnetic core made by combining two core pieces of the same shape and size. The shape of the magnetic core is the same as the magnetic core 8 shown in Figure 6. Each core piece comprises one first block portion and three second block portions. The first block portion is positioned to face the end face of the winding portion of the coil. The three second block portions have sides that face either the inner or outer surface of the winding portion, and are positioned so that their sides face each other. Of the three second block portions, the middle core portion has a part that is positioned inside the winding portion. Of the three second block portions, the two side core portions are positioned outside the winding portion, sandwiching the middle core portion.

[0110] In each core piece, the first block is composed of a first part and a second part. In each core piece, the second block is composed of only the second part. In each sample, the material of the compacted molded body constituting the first part is the same. In each sample, the material of the composite molded body constituting the second part is the same.

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

[0112] <Test Example 1> In Test Example 1, the first and second parts constituting the first block were stacked in a direction aligned with the height of the first block to create samples with different heights of the first part, and the effect of the height of the first part of the first block was investigated.

[0113] ≪Sample≫ Samples No. 1-1 to 1-6 were prepared, each having a first block section with a different height for the first section. Samples No. 1-1 to 1-6 have different ratios of the height of the first section H1 to the height of the first block section H0 (H1 / H0). The ratio H1 / H0 for sample No. 1-1 is 0.17. The ratio H1 / H0 for sample No. 1-2 is 0.33. The ratio H1 / H0 for sample No. 1-3 is 0.50. The ratio H1 / H0 for sample No. 1-4 is 0.67. The ratio H1 / H0 for sample No. 1-5 is 0.83. The ratio H1 / H0 for sample No. 1-6 is 1.00.

[0114] For all samples No. 1-1 to No. 1-6, the ratio of the thickness T1 of the first part to the thickness T0 of the first block, T1 / T0, is 1.00. For all samples No. 1-1 to No. 1-6, the ratio W1 / W0 of the width W1 of the first part to the width W0 of the first block, W0, is 1.00.

[0115] Samples No. 1-10 have a first block section that consists only of the second part and lacks the first part.

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

[0117] ≪Loss≫ For each sample reactor, the losses when the reactor was driven were determined. For loss analysis, commercially available electromagnetic field analysis software, JMAG-Designer 22.0 from JSOL Corporation, was used. The reactor driving conditions were: DC current 0A, input voltage 300V, output voltage 600V, and frequency 20kHz. Under these conditions, the coil loss and total loss were determined. The total loss includes the coil loss, the magnetic core loss, and the case loss when the reactor is placed in the case. The results are shown in Table 1. In Table 1, the results for samples No. 1-10 are shown as relative values ​​with the results set to 100 percent.

[0118] [Table 1]

[0119] As shown in Table 1, when the ratio H1 / H0 is greater than 0.50, the total loss is smaller compared to samples No. 1-10. When the ratio H1 / H0 is greater than 0.50, the first part, which is made of compacted powder, is distributed over a relatively wide area of ​​the first block. It is thought that the leakage flux from the first block is suppressed because the first part, which is made of compacted powder with high magnetic permeability, is distributed over a relatively wide area, thereby suppressing the deterioration of losses.

[0120] As shown in Table 1, the rate of decrease in inductance is small even when the ratio H1 / H0 increases. Although the compacted material is prone to magnetic saturation, the influence of the compacted material placed in the first block on magnetic saturation is considered to be relatively small because the first block is positioned to face the end face of the winding section. In other words, it is considered that the first block can maintain high inductance even when the ratio H1 / H0 increases.

[0121] In the first block section, it is required that the first and second sections be joined together well. If the ratio H1 / H0 is less than 1.00, the first and second sections will overlap in a direction along the height of the first block section, and the first and second sections will be joined over a relatively large surface area. Therefore, if the ratio H1 / H0 is less than 1.00, it is considered that the first and second sections can be joined together well.

[0122] [Test Example 2] In Test Example 2, the first and second parts constituting the first block were stacked in a direction aligned with the thickness of the first block to create samples with different thicknesses of the first part, and the effect of the thickness of the first part of the first block was investigated.

[0123] ≪Sample≫ Samples No. 2-1 and No. 2-5 were prepared from Sample No. 2-1, which each had a first block section with a different first section thickness. Samples No. 2-1 to No. 2-5 have different ratios T1 / T0 of the thickness of the first section T1 to the thickness of the first block section T0. The ratio T1 / T0 for Sample No. 2-1 is 0.29. The ratio T1 / T0 for Sample No. 2-2 is 0.47. The ratio T1 / T0 for Sample No. 2-3 is 0.65. The ratio T1 / T0 for Sample No. 2-4 is 0.82. The ratio T1 / T0 for Sample No. 2-5 is 1.00.

[0124] In all samples No. 2-1 to No. 2-5, the ratio of the height H1 of the first part to the height H0 of the first block (H1 / H0) is 1.00. In all samples No. 2-1 to No. 2-5, the ratio of the width W1 of the first part to the width W0 of the first block (W1 / W0) is 1.00.

[0125] Sample No. 2-10 has a first block section composed only of the second part and lacks the first part. Sample No. 2-10 is the same as Sample No. 1-10.

[0126] Inductance For each sample reactor, the inductance was determined when a DC current of 250A was passed through the coil, similar to the procedure in Test Example 1. The results are shown in Table 2. In Table 2, the results for samples No. 2-10 are shown as relative values, with the results set to 100 percent.

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

[0128] [Table 2]

[0129] As shown in Table 2, when the ratio T1 / T0 is greater than 0.47, the total loss is smaller compared to sample No. 2-10. When the ratio T1 / T0 is greater than 0.47, the first part, which is made of compacted powder, is distributed over a relatively wide area of ​​the first block. It is thought that the leakage flux from the first block is suppressed because the first part, which is made of compacted powder with high magnetic permeability, is distributed over a relatively wide area, thereby suppressing the deterioration of losses.

[0130] As shown in Table 2, the rate of decrease in inductance is small even when the ratio T1 / T0 increases. Although the compacted material is prone to magnetic saturation, the influence of the compacted material placed in the first block on magnetic saturation is considered to be relatively small because the first block is positioned to face the end face of the winding section. In other words, it is considered that the first block can maintain high inductance even when the ratio T1 / T0 increases.

[0131] Considering both Test Example 1 and Test Example 2 together, 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, losses can be reduced, and the first and second parts can be joined to each other well.

[0132] [Test Example 3] In Test Example 3, the first and second parts constituting the first block were overlapped in a direction aligned with the width of the first block to create samples with different widths of the first part, and the effect of the width of the first part of the first block was investigated.

[0133] ≪Sample≫ Samples No. 3-1 and No. 3-6 were prepared from Sample No. 3-1, which each has a first block section with a different width for the first section. Samples No. 3-1 to No. 3-6 have different ratios W1 / W0 of the width of the first section to the width W0 of the first block section. The ratio W1 / W0 for Sample No. 3-1 is 0.33. The ratio W1 / W0 for Sample No. 3-2 is 0.47. The ratio W1 / W0 for Sample No. 3-3 is 0.60. The ratio W1 / W0 for Sample No. 3-4 is 0.73. The ratio W1 / W0 for Sample No. 3-5 is 0.87. The ratio W1 / W0 for Sample No. 3-6 is 1.00.

[0134] In all samples No. 3-1 to No. 3-6, the ratio of the height H1 of the first part to the height H0 of the first block (H1 / H0) is 1.00. In all samples No. 3-1 to No. 3-6, the ratio of the thickness T1 of the first part to the thickness T0 of the first block (T1 / T0) is 1.00.

[0135] Sample No. 3-10 has a first block section composed only of the second part and lacks the first part. Sample No. 3-10 is the same as Sample No. 1-10.

[0136] Inductance For each sample reactor, the inductance was determined when a DC current of 250A was passed through the coil, similar to the procedure in Test Example 1. The results are shown in Table 3. In Table 3, the results for samples No. 3-10 are shown as relative values, with the results set to 100 percent.

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

[0138] [Table 3]

[0139] As shown in Table 3, all of samples No. 3-1 through No. 3-6 exhibit smaller total losses compared to sample No. 3-10. Comparing each of samples No. 3-1 through No. 3-6, a larger ratio W1 / W0 results in smaller losses in the coil and smaller total losses. A larger ratio W1 / W0 means that the first portion, composed of compacted powder, is distributed over a relatively wide area of ​​the first block. It is thought that the distribution of the first portion, composed of highly permeable compacted powder, over a relatively wide area suppresses leakage flux from the first block, thereby preventing the deterioration of losses.

[0140] As shown in Table 3, the rate of decrease in inductance is small even when the ratio W1 / W0 increases. Although the compacted material is prone to magnetic saturation, the influence of the compacted material placed in the first block on magnetic saturation is considered to be relatively small because the first block is positioned to face the end face of the winding section. In other words, it is considered that the first block can maintain high inductance even when the ratio W1 / W0 increases.

[0141] Considering both Test Example 1 and Test Example 3 together, 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 greater, losses can be minimized, and the first and second parts can be joined to each other well. [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 view 120 Second Block Section 125 Side view 2,21,22 Middle Core Section 3,31,32 Side core section 4,41,42 Side core section 5 End core section 6. End core section 2g gap 7 Reactor 8 magnetic cores 81 First core piece 82 Second core piece 9 coils 90-volume section 91 End face 92 Inner surface 93 External surface D1 first direction, D2 second direction, D3 third direction H0, H1 Height T0, T1 thickness W0,W1 width 1100 Power converter, 1110 Converter, 1111 Switching element 1112 Drive circuit, 1115 Reactor, 1120 Inverter 1150 Converter for power supply equipment, 1160 Converter for auxiliary power supply equipment 1200 vehicles, 1210 main batteries, 1220 motors 1230 Sub-battery, 1240 Auxiliary equipment, 1250 Wheels, 1300 Engine

Claims

1. A core piece for forming a magnetic core that is placed inside and outside a coil, A first block portion is arranged so as to face the end face of the coil, The coil comprises a plurality of second block sections, each having a side surface facing either the inner or outer surface of the coil, and the sides of which are arranged to face each other. The aforementioned first block section is, The first part is composed of a compacted molded body of soft magnetic powder, A second part comprising a molded body of a composite material in which soft magnetic powder is dispersed in a resin, The first part and the second part overlap in a direction along the height of the first block. The ratio of the height of the first part to the height of the first block is greater than 0.5 and less than 1. The height of the first block portion and the height of the first part are lengths along directions perpendicular to both the direction along the axis of the coil and the direction in which the plurality of second block portions are aligned. Core piece.

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

3. The first block portion comprises a first surface and a second surface facing each other in a direction along the height of the first block portion, The first part 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 the thickness of the first block portion. The ratio of the thickness of the first part to the thickness of the first block is 0.6 or more. The core piece according to claim 1 or claim 2, wherein the thickness of the first block portion and the thickness of the first portion are each the length along the axis of the coil.

5. The first block portion is provided with an outer end surface facing outward in the 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 is composed of a set of a first core piece and a second core piece, The magnetic core comprises a coil disposed in part of the magnetic core, At least one of the first core piece and the second core piece is the core piece described in claim 1 or claim 2. Reactor.

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

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

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