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

Abstract

To provide a reactor with less cracks in a magnetic core.SOLUTION: In a reactor, a coil includes one winding portion, the magnetic core includes a first core piece and a second core piece that are combined with each other, and at least one of the first core piece and the second core piece is constituted by a molded composite material in which soft magnetic powder is dispersed in a resin, the magnetic core in a state in which the first core piece and the second core piece are combined includes a middle core portion, two side core portions, and two end core portions, the middle core portion includes a portion located inside the winding portion, each of the two side core portions is arranged side by side with the middle core portion outside the winding portion, each of the two end core portions is arranged to connect the middle core portion and the two side core portions outside the ends of the winding portion, a mold resin portion covers at least a part of the magnetic core, and an elastic body is provided so as to divide at least one of the middle of the middle core portion and the boundary between the middle core portion and the end core portion.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 discloses a reactor including a coil, a magnetic core, and a resin molded part. The magnetic core is formed by combining a plurality of core pieces and a gap material. The resin molded part integrates the coil and the magnetic core. The resin molded part is formed by injection molding. Specifically, the resin molded part is formed by placing an assembly of the coil and the magnetic core in a mold, filling the mold with unsolidified constituent resin of the resin molded part, and solidifying the unsolidified constituent resin. In the mold, a gap corresponding to the thickness of the gap material is formed between each core piece of the magnetic core. The gap material is formed by the unsolidified constituent resin flowing into the gap formed between the plurality of core pieces and solidifying. Hereinafter, the resin molded part is referred to as a molded resin part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-171136 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the molded resin portion is formed by injection molding, the magnetic core may crack due to the pressure applied during injection molding depending on the shape of the magnetic core. Therefore, for example, depending on the shape of the magnetic core, there is a restriction on the pressure applied during injection molding.

[0005] An object of the present disclosure is to provide a reactor with less cracks in the magnetic core.Another object of the present disclosure is to provide a converter including the reactor.Another object of the present disclosure is to provide a power conversion device including the converter.Another object of the present disclosure is to provide a manufacturing method for a reactor in which cracks are less likely to occur in the magnetic core even when high pressure is applied during the manufacturing process. [Means for solving the problem]

[0006] The reactor of the present disclosure comprises a coil, a magnetic core, a molded resin portion, and an elastic body, the coil comprising one winding portion, the magnetic core comprising first core pieces and second core pieces combined with each other, at least one of the first core pieces and the second core pieces being composed of a molded body of a composite material in which soft magnetic powder is dispersed in resin, the magnetic core in a state in which the first core pieces and the second core pieces are combined comprises a middle core portion, two side core portions, and two end core portions, the middle core portion has a portion that is arranged inside the winding portion, each of the two side core portions is arranged side by side with the middle core portion outside the winding portion, each of the two end core portions is arranged outside an end of the winding portion so as to connect the middle core portion and the two side core portions, the molded resin portion covers at least a portion of the magnetic core, and the elastic body is provided so as to divide at least one of the middle core portions or the boundaries between the middle core portion and the end core portions.

[0007] The converter of the present disclosure includes the reactor of the present disclosure.

[0008] The power conversion device of the present disclosure includes the converter of the present disclosure.

[0009] A method for manufacturing a reactor according to the present disclosure includes a step of preparing an assembly including a coil, a magnetic core, and an elastic body, and a step of placing the assembly in a mold and injecting resin into the mold to form a molded resin portion so as to cover at least a portion of the magnetic core, wherein the coil includes one winding portion, the magnetic core includes first core pieces and second core pieces that are combined with each other, and at least one of the first core pieces and the second core pieces is formed of a molded body of a composite material in which soft magnetic powder is dispersed in resin, and the magnetic core in a state in which the first core pieces and the second core pieces are combined includes a middle core portion, two side core portions, and two end core portions. and a core portion, the middle core portion having a portion that is arranged inside the winding portion, each of the two side core portions being arranged side by side with the middle core portion outside the winding portion, and each of the two end core portions being arranged outside the ends of the winding portion so as to connect the middle core portion and the two side core portions, the preparing step being such that the elastic body is arranged so as to divide at least one of the middle core portion or the boundary between the middle core portion and the end core portion, and the forming step being such that a pressure of 15 MPa or more is applied in a direction in which the two end core portions approach each other. Effect of the Invention

[0010] In the reactor of the present disclosure, the magnetic core is less likely to crack. In the converter and the power conversion device of the present disclosure, the magnetic core is less likely to crack. In the manufacturing method of the reactor of the present disclosure, the magnetic core is less likely to crack even when high pressure is applied during the manufacturing process. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing an outline of a reactor according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a flow of magnetic flux in a magnetic core of the reactor of FIG. [Diagram 3] FIG. 3 is an explanatory diagram illustrating the first area ratio of the elastic body after compression. [Figure 4]FIG. 4 is an explanatory diagram illustrating the second area ratio of the elastic body after compression. [Diagram 5] FIG. 5 is an explanatory diagram illustrating a molding step in the method for producing the reactor of the first embodiment. [Figure 6] FIG. 6 is an explanatory diagram illustrating a first area ratio of the elastic body before compression. [Figure 7] FIG. 7 is an explanatory diagram illustrating the second area ratio of the elastic body before compression. [Figure 8] FIG. 8 is a cross-sectional view illustrating an outline of a reactor according to the second embodiment. [Figure 9] FIG. 9 is a cross-sectional view illustrating an outline of a reactor according to the third embodiment. [Figure 10] FIG. 10 is a cross-sectional view illustrating an outline of a reactor according to the fourth embodiment. [Figure 11] FIG. 11 is a cross-sectional view illustrating an outline of a reactor according to the fifth embodiment. [Figure 12] FIG. 12 is a schematic diagram showing a power supply system of a hybrid vehicle. [Figure 13] FIG. 13 is a circuit diagram showing an outline of an example of a power conversion device including a converter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be listed and described.

[0013] (1) A reactor according to an embodiment of the present disclosure comprises a coil, a magnetic core, a molded resin portion, and an elastic body, the coil comprising one winding portion, the magnetic core comprising first core pieces and second core pieces combined with each other, at least one of the first core pieces and the second core pieces being composed of a molded body of a composite material in which soft magnetic powder is dispersed in resin, the magnetic core in a state in which the first core pieces and the second core pieces are combined comprises a middle core portion, two side core portions, and two end core portions, the middle core portion has a portion that is arranged inside the winding portion, each of the two side core portions is arranged side by side with the middle core portion outside the winding portion, each of the two end core portions is arranged outside an end of the winding portion to connect the middle core portion and the two side core portions, the molded resin portion covers at least a portion of the magnetic core, and the elastic body is provided so as to divide at least one of the middle core portions or the boundaries between the middle core portion and the end core portions.

[0014] In the reactor of the present disclosure, an elastic body is provided in the middle or at the end of the middle core portion, so that the magnetic core is less likely to crack. The reactor of the present disclosure is obtained by a manufacturing method described below. Specifically, the reactor of the present disclosure is obtained by arranging an assembly including a coil, a magnetic core, and an elastic body in a mold, and injecting resin into the mold to form a molded resin portion. When forming the molded resin portion, pressure is applied in a direction in which the two end core portions approach each other. In the reactor of the present disclosure, an elastic body is provided in the middle or at the end of the middle core portion, which is easily affected by the pressure, so that the load due to the pressure can be absorbed by the elastic body during the manufacturing process, and the magnetic core is less likely to crack. Since the magnetic core is less likely to crack during the manufacturing process, the obtained reactor of the present disclosure has less cracks in the magnetic core.

[0015] In general, in order to maintain a predetermined inductance, a gap material is provided in a core part having a part arranged inside the winding part of the magnetic core. In a magnetic core having a middle core part, two side core parts, and two end core parts, such as the reactor of the present disclosure, a gap material is provided in the middle core part. When the gap material is molded with the constituent resin of the molded resin part, as in the technology described in Patent Document 1, a gap is provided in the middle core part in the manufacturing process of the reactor, into which the unsolidified constituent resin of the molded resin part is filled. When a gap is provided in the middle core part, both ends of the end core part are supported by the side core part, while the center part of the end core part is not supported by the gap and is in a floating state. When the unsolidified constituent resin is injection molded in this state, a load is likely to be applied to the center part of the end core part with both ends of the end core part as fulcrums.

[0016] In the reactor of the present disclosure, by using an elastic body as the gap material, a predetermined inductance can be maintained, the load can be absorbed by the elastic body, and the magnetic core is less likely to crack. By using an elastic body as the gap material, it is also possible to expect the effect of making it easier to adjust the gap length. The gap in which the elastic body is disposed is formed between the first core piece and the second core piece when the first core piece and the second core piece are combined. The gap length is the length of the gap along the axial direction of the middle core part. The gap length is equal to the thickness of the elastic body in a compressed state.

[0017] (2) As one embodiment of the reactor, the two side core portions and The two end cores and is configured in a series.

[0018] In the above embodiment, no elastic body is required for each of the two side core parts and the two end core parts, the number of parts is small, and the reactor is excellent in assembly. "Constructed in a continuous manner" includes the following two embodiments. The first embodiment is a form in which all core parts are constructed of an integral molded body as at least a part of a single core piece of the first core piece or the second core piece. For example, when one side core part is viewed, the side core part is constructed as a part of the first core piece or the second core piece. The second embodiment is a form in which one core part is constructed of two molded bodies divided as parts of the first core piece and the second core piece, respectively, but the divided core parts are configured to directly contact each other without any other member. For example, when one side core part is viewed, a form in which a part of the side core part is constructed by the first core piece and the remaining part of the side core part is constructed by the second core piece. In this embodiment, when the first core piece and the second core piece are combined, a part of the side core part in the first core piece and the remaining part of the side core part in the second core piece are directly contacted without any other member, and are configured continuously. (3) As one embodiment of the reactor, the ratio of the area of ​​the elastic body to a specific area is 70% or more, the specific area is calculated by length A x length B, the length A is the length of the middle core part along a direction perpendicular to both the longitudinal direction of the middle core part and the parallel direction of the middle core part and the two side core parts, the length B is the length between the inner surfaces of the two side core parts, and the area of ​​the elastic body is the area of ​​the surface of the elastic body in a compressed state facing the middle core part.

[0019] Length B corresponds to the distance between the fulcrums that connect the fulcrums supported by the side core portions at both ends of the end core portion. The specific area is an area that is easily affected by the pressure applied when forming the molded resin portion during the reactor manufacturing process. In this area, the fulcrums are easily bent. By providing an elastic body within a certain range of the specific area, the elastic body can easily absorb the load applied to the middle core portion, making it more difficult for cracks to occur in the magnetic core. Since cracks are less likely to occur in the magnetic core during the manufacturing process, the reactor of the present disclosure obtained has fewer cracks in the magnetic core.

[0020] (4) In one embodiment of the reactor, a ratio of an area of ​​the elastic body to a cross-sectional area of ​​the middle core portion is 70% or more, and the cross-sectional area of ​​the middle core portion is The middle core portion The area is the area of ​​a cross section cut in a direction perpendicular to the longitudinal direction of the middle core portion, and the area of ​​the elastic body is the area of ​​a surface of the elastic body in a compressed state that faces the middle core portion.

[0021] By providing the elastic body over a certain range of the cross-sectional area of ​​the middle core portion, the load applied to the middle core portion can be easily absorbed by the elastic body, and cracks are less likely to occur in the magnetic core. Because cracks are less likely to occur in the magnetic core during the manufacturing process, the reactor of the present disclosure has fewer cracks in the magnetic core.

[0022] (5) In one embodiment of the reactor, the elastic body is made of silicone rubber or butyl rubber.

[0023] In the above embodiment, the load applied to the middle core portion is easily absorbed by the elastic body, and cracks are less likely to occur in the magnetic core. Since cracks are less likely to occur in the magnetic core during the manufacturing process, the reactor of the present disclosure has fewer cracks in the magnetic core.

[0024] (6) As one embodiment of the reactor, each of the first core lamination and the second core lamination is an E-shaped member including one of the two end core portions, a portion of the middle core portion, and a portion of each of the two side core portions.

[0025] In the above embodiment, since the middle core portion is divided into the first core piece and the second core piece, the elastic body can be easily provided in the middle of the middle core portion. In the above embodiment, the two core pieces can be produced using a mold of the same shape, thereby improving the productivity of the reactor.

[0026] (7) As one embodiment of the above reactor, the first core piece is an E-shaped member including one of the two end core pieces, a part of the middle core piece, and each of the two side core pieces, and the second core piece is a T-shaped member including the other of the two end core pieces and the remaining part of the middle core piece.

[0027] In the above embodiment, since the middle core portion is divided into the first core piece and the second core piece, the elastic body can be easily provided midway through the middle core portion.

[0028] (8) One embodiment of the above reactor is such that the first core lamination is an E-shaped member including one of the two end core portions, the middle core portion, and each of the two side core portions, and the second core lamination is an I-shaped member including the other of the two end core portions.

[0029] In the above embodiment, the elastic body can be easily provided between one end of the middle core portion of the first core piece and the second core piece, i.e., the end core portion.

[0030] (9) As one embodiment of the above reactor, the first core piece is an E-shaped member including one of the two end core pieces, the middle core piece, and a portion of each of the two side core pieces, and the second core piece is a U-shaped member including the other of the two end core pieces and a remaining portion of each of the two side core pieces.

[0031] In the above embodiment, the elastic body can be easily provided between one end of the middle core portion of the first core piece and the end core portion of the second core piece.

[0032] (10) As one embodiment of the above reactor, the first core lamination is an O-shaped member including each of the two end core portions and each of the two side core portions, and the second core lamination is an I-shaped member including the middle core portion.

[0033] In the above embodiment, the elastic body can be easily provided between at least one end of the second core piece, i.e., the middle core portion, and the end core portion of the first core piece.

[0034] (11) A converter according to an embodiment of the present disclosure includes the reactor according to any one of (1) to (10) above.

[0035] The converter of the present disclosure includes the reactor of the present disclosure, and therefore has fewer cracks in the magnetic core.

[0036] (12) A power conversion device according to an embodiment of the present disclosure includes the converter described above in (11).

[0037] Since the power conversion device of the present disclosure includes the converter of the present disclosure, the magnetic core is less susceptible to cracks.

[0038] (13) A method of manufacturing a reactor according to an embodiment of the present disclosure includes the steps of preparing an assembly including a coil, a magnetic core, and an elastic body, and placing the assembly in a mold and injecting resin into the mold to form a molded resin portion so as to cover at least a portion of the magnetic core, wherein the coil includes one winding portion, the magnetic core includes first core pieces and second core pieces combined with each other, at least one of the first core pieces and the second core pieces is configured as a molded body of a composite material in which soft magnetic powder is dispersed in resin, and the magnetic core in a state in which the first core pieces and the second core pieces are combined includes a middle core portion, two side core portions, and two the middle core portion has a portion that is arranged inside the winding portion, each of the two side core portions is arranged side by side with the middle core portion outside the winding portion, and each of the two end core portions is arranged outside the ends of the winding portion so as to connect the middle core portion and the two side core portions, the preparing step arranges the elastic body so as to divide at least one of the middle core portion or the boundary between the middle core portion and the end core portion, and the molding resin portion forming step applies a pressure of 15 MPa or more in a direction in which the two end core portions approach each other.

[0039] In the method for manufacturing a reactor according to the present disclosure, the magnetic core is less likely to crack even when a high pressure of 15 MPa or more is applied when forming the molded resin part. This is because, in the method for manufacturing a reactor according to the present disclosure, an elastic body is provided in the middle or end of the middle core part, which is easily affected by the pressure, and the load caused by the pressure can be absorbed by the elastic body.

[0040] As described above, in general, in order to maintain a predetermined inductance, a gap material is provided in a core part having a portion of the magnetic core that is disposed inside the winding part. When the gap material is molded with the constituent resin of the molded resin part as in the technology described in Patent Document 1, a gap is provided in the middle core part in which the unsolidified constituent resin of the molded resin part is filled in the manufacturing process of the reactor. When a gap is provided in the middle core part, both ends of the end core part are supported by the side core part, whereas the center part of the end core part is not supported by the gap and is in a floating state. When the unsolidified constituent resin is injection molded in this state, a load is likely to be applied to the center part of the end core part with both ends of the end core part as fulcrums.

[0041] In the reactor manufacturing method of the present disclosure, by using an elastic body as the gap material, a predetermined inductance can be maintained, the load can be absorbed by the elastic body, and the magnetic core is less likely to crack. By using an elastic body as the gap material, it is also expected that the gap length can be easily adjusted.

[0042] (14) As one embodiment of a method for manufacturing the above-mentioned reactor, in the preparing step, a non-compressed elastic body having an area of ​​45% or more of a specific area is arranged, and the specific area is calculated by length A x length B, where length A is the length of the middle core portion along a direction perpendicular to both the longitudinal direction of the middle core portion and the parallel direction of the middle core portion and the two side core portions, and length B is the length between the inner surfaces of the two side core portions.

[0043] The length B corresponds to the distance between the fulcrums that connect the fulcrums supported by the side core portions at both ends of the end core portion. The specific area is an area that is easily affected by the pressure applied when forming the molded resin portion. In this area, the fulcrums are easily bent. By providing an elastic body within a certain range of the specific area, the elastic body can easily absorb the load applied to the middle core portion, making it more difficult for cracks to occur in the magnetic core.

[0044] (15) As one aspect of the method for manufacturing the reactor, in the preparing step, a non-compressed elastic body having an area of ​​75% or more and 95% or less of a cross-sectional area of ​​the middle core portion is disposed, and the cross-sectional area of ​​the middle core portion is The middle core portion The area is a cross-sectional area taken along a direction perpendicular to the longitudinal direction of the middle core portion.

[0045] By providing the elastic body over a certain range of the cross-sectional area of ​​the middle core portion, the load applied to the middle core portion can be easily absorbed by the elastic body, making it less likely that cracks will occur in the magnetic core. When a load is applied to the middle core portion, the elastic body is compressed. The compressed elastic body protrudes from the outer peripheral portion of the middle core portion. By arranging an elastic body having an area of ​​95% or less of the cross-sectional area of ​​the middle core portion, it is possible to prevent the compressed elastic body from protruding too much from the outer peripheral portion of the middle core portion.

[0046] [Details of the embodiment of the present disclosure] Specific examples of reactors according to 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.

[0047] <Embodiment 1> A reactor 1 according to a first embodiment will be described with reference to Fig. 1 to Fig. 7. The reactor 1 includes a coil 2, a magnetic core 3, and a molded resin part 9. One of the features of the reactor 1 according to the first embodiment is that an elastic body 10 is provided so as to divide a middle core part 4 constituting the magnetic core 3. Each component will be described in detail below.

[0048] FIG. 1 shows an outline of the reactor 1. In FIG. 1, only the contour of the molded resin portion 9 provided on the outer periphery of the magnetic core 3 is shown by a two-dot chain line. In FIG. 2, the flow of magnetic flux in the magnetic core 3 of the reactor 1 in FIG. 1 is shown by a two-dot chain arrow. FIG. 3 and FIG. 4 show only the second core piece 32 and the elastic body 10 of the reactor 1 in FIG. 1. The upper diagrams of FIG. 3 and FIG. 4 are views of the second core piece 32 and the elastic body 10 from the third direction D3. The lower diagrams of FIG. 3 and FIG. 4 are views of the second core piece 32 from the outside in the first direction D1. The third direction D3 and the first direction D1 will be described later. The elastic body 10 shown in FIG. 1 to FIG. 4 is in a compressed state. FIG. 5 shows a state in which an assembly including the coil 2, the magnetic core, and the elastic body 10α is placed in a mold 100 in the process of manufacturing the reactor 1. 6 and 7 show only the second core pieces 32 and the elastic body 10α that constitute the magnetic core 3 out of the above-mentioned assembly. The elastic body 10α shown in Figs. 5 to 7 is in an uncompressed state prior to compression in the manufacturing process.

[0049] <Coil> As shown in Fig. 1, the coil 2 has one winding section 20. The winding section 20 is formed by winding one wire in a spiral shape. Both ends of the wire are pulled out from each axial end of the winding section 20. Terminal fittings (not shown) are attached to both ends of the wire pulled out from the winding section 20. An external device such as a power source (not shown) is connected to the terminal fittings. Note that Fig. 1 etc. only shows the winding section 20, and the ends of the wire etc. are omitted.

[0050] The winding wire may be a covered wire having a conductor wire and an insulating coating. The conductor wire may be made of copper or the like. The insulating coating may be made of a resin such as polyamideimide. The covered wire may be a covered rectangular wire having a rectangular cross section or a covered round wire having a circular cross section.

[0051] The coil 2 in this example is a rectangular cylindrical edgewise coil in which a coated rectangular wire is wound edgewise. Therefore, the end face shape of the winding part 20 when viewed from the axial direction is rectangular. The rectangle includes a square as well as a rectangle. The winding part 20 has four flat surfaces and four corners. Each corner is rounded. The surfaces of the winding part 20 other than the corners are substantially composed of flat surfaces. Therefore, it is easy to ensure a large contact area between the winding part 20 and the installation object. Because the contact area is large, the winding part 20 is easily held stably on the installation object. In addition, because the contact area is large, the reactor 1 is easy to dissipate heat to the installation object through the winding part 20. The winding part 20 may be a cylindrical coil.

[0052] <Magnetic core> 1, the magnetic core 3 includes first core pieces 31 and second core pieces 32 that are combined with each other. The magnetic core 3 is configured in a θ shape as a whole by combining the first core pieces 31 and the second core pieces 32. The magnetic core 3 in a state in which the first core pieces 31 and the second core pieces 32 are combined includes a middle core portion 4, two side core pieces 5, 6, and two end core pieces 7, 8. In this example, the first core pieces 31 and the second core pieces 32 are each an E-shaped member.

[0053] In the following, the overall shape of the magnetic core 3 will be described first, and then the shapes of the first core piece 31 and the second core piece 32 constituting the magnetic core 3 will be described. In the following description, the direction along the axial direction of the winding portion 20 is referred to as a first direction D1, the parallel direction of one middle core piece 4 and two side core pieces 5, 6 is referred to as a second direction D2, and the direction perpendicular to both the first direction D1 and the second direction D2 is referred to as a third direction D3. In the following description, the side of each side core piece 5, 6 farther from the winding portion 20 is referred to as the outer side, and the side of each side core piece 5, 6 closer to the winding portion 20 is referred to as the inner side. Similarly, the side of each end core piece 7, 8 farther from the winding portion 20 is referred to as the outer side, and the side of each end core piece 7, 8 closer to the winding portion 20 is referred to as the inner side.

[0054] [Overall shape of magnetic core] The middle core portion 4 has a portion disposed inside the winding portion 20. Each of the two side core portions 5, 6 is disposed side by side with the middle core portion 4 outside the winding portion 20. Each of the two end core portions 7, 8 is disposed so as to connect the middle core portion 4 and the two side core portions 5, 6 outside the end portion of the winding portion 20. In the magnetic core 3, the middle core portion 4, the two side core portions 5, 6, and the two end core portions 7, 8 are connected to each other, so that magnetic flux flows when the coil 2 is excited, forming a closed magnetic circuit. As shown by the two-dot chain line arrows in FIG. 2, the magnetic flux flows from the middle core portion 4 to the end core portion 7, flows from the end core portion 7 to each of the two side core portions 5, 6, flows from each side core portion 5, 6 to the end core portion 8, and flows from the end core portion 8 to the middle core portion 4.

[0055] (Middle core section) The shape of the middle core part 4 roughly corresponds to the inner peripheral shape of the winding part 20. In this example, the shape of the middle core part 4 is a quadrangular prism, more specifically, a rectangular prism, and the end face shape of the middle core part 4 viewed from the axial direction is rectangular. The corners of the middle core part 4 are rounded to fit the corners of the winding part 20. A gap exists between the outer peripheral surface of the middle core part 4 and the inner peripheral surface of the winding part 20. A molded resin part 9, which will be described later, is configured in at least a part of this gap.

[0056] 1, the middle core portion 4 of this example is composed of a first middle core portion 41 and a second middle core portion 42. An elastic body 10, which will be described later, is provided between the first middle core portion 41 and the second middle core portion 42. In other words, the middle core portion 4 of this example is divided midway by the elastic body 10.

[0057] The length of the middle core portion 4 in the first direction D1 is equal to or greater than the length of the winding portion 20 in the first direction D1. In this example, the length of the middle core portion 4 in the first direction D1 is slightly longer than the length of the winding portion 20 in the first direction D1, as shown in FIG. 1 . The middle core portion 4 in this example has a portion that is disposed inside the winding portion 20 and a portion that is disposed outside the winding portion 20. Both end portions of the middle core portion 4 are located outside the winding portion 20.

[0058] (Side core part) The shape of each side core portion 5, 6 is not particularly limited as long as it extends along the first direction D1 outside the winding portion 20. In this example, each side core portion 5, 6 is a rectangular parallelepiped extending along the first direction D1. Each side core portion 5, 6 is arranged so as to sandwich the winding portion 20 from the outside. When the winding portion 20 is a rectangular cylindrical edgewise coil, each side core portion 5, 6 is arranged so as to face two faces that face each other among the four faces that constitute the outer circumferential surface of the winding portion 20. The faces of the winding portion 20 that do not face the two side core portions 5, 6 are exposed from the magnetic core 3.

[0059] 1, the side core portion 5 of this example is composed of a first side core portion 51 and a second side core portion 52. The first side core portion 51 and the second side core portion 52 are in direct contact with each other and are thus continuously formed without being separated. In other words, there is no gap or gap material between the first side core portion 51 and the second side core portion 52.

[0060] Like the side core portion 5, the side core portion 6 of this example is composed of a first side core portion 61 and a second side core portion 62. The first side core portion 61 and the second side core portion 62 are in direct contact with each other and are thus formed as a continuous piece without being separated. In other words, no gap or gap material is provided between the first side core portion 51 and the second side core portion 52.

[0061] In this example, the two side core portions 5, 6 have the same shape and size. The length of each side core portion 5, 6 along the first direction D1 is longer than the length of the middle core portion 4 along the first direction D1. In this example, the length of each side core portion 5, 6 along the second direction D2 is shorter than the length of the middle core portion 4 along the second direction D2. In this example, the sum of the length of the side core portion 5 along the second direction D2 and the length of the side core portion 6 along the second direction D2 is shorter than the length of the middle core portion 4 along the second direction D2. In this example, the length of each side core portion 5, 6 along the third direction D3 is the same as the length of the middle core portion 4 along the third direction D3. The sum of the lengths of each side core portion 5, 6 along the second direction D2 may be the same as or longer than the length of the middle core portion 4 along the second direction D2. The length of each side core portion 5, 6 along the third direction D3 may be shorter or longer than the length of the middle core portion 4 along the third direction D3. The length of each side core portion 5, 6 along the third direction D3 is shorter than the length of the wound portion 20 along the third direction D3. The length of each side core portion 5, 6 along the third direction D3 may be equal to or greater than the length of the wound portion 20 along the third direction D3. The two side core portions 5, 6 may have different shapes and dimensions.

[0062] (End core part) The shape of each of the end core portions 7, 8 is not particularly limited as long as it connects the respective ends of one middle core portion 4 and the two side core portions 5, 6. In this example, each of the end core portions 7, 8 has a rectangular parallelepiped shape that is elongated in the second direction D2.

[0063] In this example, the two end core portions 7, 8 have the same shape and dimensions. The length of each end core portion 7, 8 along the first direction D1 is approximately the same as the length of each side core portion 5, 6 along the second direction D2. The length of each end core portion 7, 8 along the third direction D3 is the same as the length of the middle core portion 4 and each side core portion 5, 6 along the third direction D3. The shapes and dimensions of the two end core portions 7, 8 may be different.

[0064] [Shapes of the first core piece and the second core piece] The first core pieces 31 and the second core pieces 32 are split pieces obtained by splitting the magnetic core 3 apart in the first direction D1, as shown in FIG. 1. The first core pieces 31 and the second core pieces 32 in this example are E-shaped members of the same shape. The first core pieces 31 and the second core pieces 32 in this example also have the same dimensions. The position at which the first core pieces 31 and the second core pieces 32 are split is the center of the magnetic core 3 in the first direction D1. Since the first core pieces 31 and the second core pieces 32 have the same shape, they can be manufactured using a mold of the same shape. The shapes and dimensions of the first core pieces 31 and the second core pieces 32 may be different.

[0065] The first core piece 31 includes an end core piece 7, a first middle core piece 41, and two first side core pieces 51, 61. The second core piece 32 includes an end core piece 8, a second middle core piece 42, and two second side core pieces 52, 62.

[0066] Each of the first middle core portion 41 and the second middle core portion 42 is a part of the middle core portion 4. The first middle core portion 41 and the second middle core portion 42 have the same length along the first direction D1. A gap is provided between the first middle core portion 41 and the second middle core portion 42. An elastic body 10, which will be described later, is provided in this gap.

[0067] Each of the first side core portion 51 and the second side core portion 52 is a part of the side core portion 5. The first side core portion 51 and the second side core portion 52 have the same length along the first direction D1. There is no gap between the first side core portion 51 and the second side core portion 52. The first side core portion 51 and the second side core portion 52 are in direct contact with each other and thus constitute a continuous portion. The side core portion 5 is constituted as a continuous portion without being divided by the first side core portion 51 and the second side core portion 52 which are in direct contact with each other.

[0068] Each of the first side core portion 61 and the second side core portion 62 is a part of the side core portion 6. The first side core portion 61 and the second side core portion 62 have the same length along the first direction D1. There is no gap between the first side core portion 61 and the second side core portion 62. The first side core portion 61 and the second side core portion 62 are configured to be continuous by being in direct contact with each other. The side core portion 6 is configured as a continuous piece without being divided by the first side core portion 61 and the second side core portion 62 which are in direct contact with each other.

[0069] [Constituent materials] At least one of the first core piece 31 and the second core piece 32 is composed of a composite material molded body. The composite material molded body is formed by dispersing soft magnetic powder in resin. The composite material molded body is obtained 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 relative permeability and 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 relative permeability can be easily reduced. Furthermore, the composite material can be easily formed into a complex shape compared to a powder compact described later. The content of the soft magnetic powder in the composite material molded body can be, for example, 20% by volume or more and 80% by volume or less, assuming that the composite material is 100% by volume. The content of the resin in the composite material molded body can be, for example, 20% by volume or more and 80% by volume or less, assuming that the composite material is 100% by volume.

[0070] The powder compact is obtained by compressing and molding a powder made of a soft magnetic material, i.e., soft magnetic powder. Compared to a composite material compact, the powder compact can have a higher ratio of soft magnetic powder in the core pieces. Therefore, the powder compact can easily have high magnetic properties, such as the relative permeability and saturation magnetic flux density. The content of the soft magnetic powder in the powder compact can be, for example, more than 80% by volume, or even 85% by volume or more, assuming that the powder compact is 100% by volume.

[0071] The soft magnetic powder is an aggregate of soft magnetic particles. The soft magnetic particles are composed of a soft magnetic material. Examples of the soft magnetic material include metals such as iron and iron alloys, and nonmetals such as ferrite. Examples of the iron alloy include Fe-Si alloys and Fe-Ni alloys. The soft magnetic particles may be coated particles having an insulating coating on the surface of the soft magnetic particles. Examples of the constituent material of the insulating coating include phosphates. Examples of the resin of the composite material include thermosetting resins and thermoplastic resins. Examples of the thermosetting resin include epoxy resins, phenolic resins, silicone resins, and urethane resins. Examples of the thermoplastic resin include polyphenylene sulfide (PPS) resins, polyamide (PA) resins (e.g., nylon 6, nylon 66, nylon 9T, etc.), liquid crystal polymers (LCP), polyimide (PI) resins, and fluororesins. The composite material may contain a filler in addition to the resin. By containing a filler, the heat dissipation property of the composite material can be improved. For the filler, for example, a powder made of a nonmagnetic material such as ceramics or carbon nanotubes can be used. Examples of ceramics include oxides, nitrides, and carbides of metals or nonmetals. Examples of oxides include alumina, silica, and magnesium oxide. Examples of nitrides include silicon nitride, aluminum nitride, and boron nitride. Examples of carbides include silicon carbide.

[0072] One example is where both the first core pieces 31 and the second core pieces 32 are made of a composite material compact. In this case, the first core pieces 31 and the second core pieces 32 may be made of the same composite material compact, or may be made of a composite material compact with a different content of soft magnetic powder. Alternatively, one of the first core pieces 31 and the second core pieces 32 may be made of a composite material compact, and the other of the first core pieces 31 and the second core pieces 32 may be made of a powder compact.

[0073] <Molded resin part> As shown in FIG. 1, the molded resin part 9 covers at least a part of the magnetic core 3. The molded resin part 9 has a function of protecting the magnetic core 3 from the external environment. The molded resin part 9 may further cover the coil 2. If the molded resin part 9 is interposed between the coil 2 and the magnetic core 3, it is easy to ensure insulation between the coil 2 and the magnetic core 3. If the molded resin part 9 exists between the coil 2 and the magnetic core 3, it is easy to position the coil 2 and the magnetic core 3 relative to each other. Furthermore, if the molded resin part 9 exists between the first core piece 31 and the second core piece 32, it is possible to fix the first core piece 31 and the second core piece 32 to each other.

[0074] The molded resin part 9 in this example covers the outer periphery of the assembly including the coil 2, the magnetic core 3, and the elastic body 10 described later. The assembly in this example is protected from the external environment by the molded resin part 9. The assembly in this example is configured by integrating the coil 2, the magnetic core 3, and the elastic body 10 by the molded resin part 9. At least a part of the outer periphery of the magnetic core 3 or at least a part of the outer periphery of the coil 2 may be exposed from the molded resin part 9. The molded resin part 9 in this example is interposed between the inner surface of the winding part 20 and the middle core part 4.

[0075] Examples of the resin constituting the molded resin portion 9 include the same resin as the resin of the composite material described above. The constituent material of the molded resin portion 9 may contain the above-mentioned filler, like the composite material.

[0076] <Elastic body> As shown in FIG. 1, the elastic body 10 is provided so as to divide the middle core portion 4. The elastic body 10 has a function of maintaining a predetermined inductance. The elastic body 10 also has a function of absorbing a load applied to the middle core portion 4 during the manufacturing process of the reactor 1. Although details will be described later, during the manufacturing process of the reactor 1, when the molded resin portion 9 is formed, pressure is applied in a direction in which the two end core portions 7 and 8 approach each other. The pressure easily applies a load to the middle core portion 4. The elastic body 10 absorbs this load, thereby suppressing the occurrence of cracks in the magnetic core 3. The elastic body 10 is disposed opposite to each other in a region including the center of the end face of the middle core portion 4.

[0077] The first area ratio in the elastic body 10 in the compressed state is 70% or more. The first area ratio is the ratio of the area of ​​the elastic body 10 to the specific area. The specific area is calculated by multiplying the length A and the length B shown in FIG. 3, that is, length A × length B. The length A is the length along the third direction D3 in the middle core portion 4. In this example, the length along the third direction D3 in the middle core portion 4 is the same as the length along the third direction D3 in each of the end core portions 7, 8. The length B is the length between the inner surfaces of the two side core portions 5, 6. The interval between the inner surfaces of the two side core portions 5, 6 refers to the interval between the surfaces of the two side core portions 5, 6 facing each other. The specific area is a region that is easily affected by the pressure applied when forming the molded resin portion 9 in the manufacturing process of the reactor 1. The area of ​​the elastic body 10 is the area of ​​the surface of the elastic body 10 in the compressed state facing the middle core portion 4. The specific area is the portion indicated by diagonal hatching downward to the left in the lower diagram of FIG. 3. The area of ​​the elastic body 10 is the part indicated by diagonal hatching slanting downward to the right in the lower diagram of FIG.

[0078] The first area ratio in the compressed state being 70% or more means that the elastic body 10 is provided in a certain range of the specific area. By providing the elastic body 10 in a certain range to which the above pressure is applied, the load applied to the middle core portion 4 is easily absorbed by the elastic body 10 during the manufacturing process of the reactor 1, and cracks are less likely to occur in the magnetic core 3. Since cracks are less likely to occur in the magnetic core 3 during the manufacturing process of the reactor 1, a reactor 1 with fewer cracks in the magnetic core 3 can be obtained. The larger the first area ratio, the easier it is for the elastic body 10 to absorb the above load. However, if the first area ratio is too large, the elastic body 10 reaches the inner circumferential surface of the winding portion 20. When the elastic body 10 reaches the inner circumferential surface of the winding portion 20, the gap between the middle core portion 4 and the winding portion 20 is divided in the axial direction of the winding portion 20, sandwiching the elastic body 10. As a result, there is a risk that the elastic body 10 will hinder the flow of the unsolidified constituent resin of the molded resin portion 9. In addition, when the elastic body 10 reaches the inner peripheral surface of the winding portion 20, the elastic body 10 may spread outside the middle core portion 4 in the axial direction of the middle core portion 4, and the elastic body 10 may be damaged at the corners of the middle core portion 4. In addition, when the elastic body 10 reaches the inner peripheral surface of the winding portion 20, when the unsolidified constituent resin of the molded resin portion 9 flows between the winding portion 20 and the middle core portion 4, the elastic body 10 may be pulled by the flow of the constituent resin and may be broken. Therefore, the first area ratio may be 95% or less. The first area ratio may be 70% or more and 95% or less, further 75% or more and 90% or less, and particularly 80% or more and 85% or less.

[0079] The second area ratio of the elastic body 10 in the compressed state is 70% or more. The second area ratio is the ratio of the area of ​​the elastic body 10 to the cross-sectional area of ​​the middle core portion 4. The cross-sectional area of ​​the middle core portion 4 is Middle core part 4 It is the area of ​​a cross section cut in a direction perpendicular to the longitudinal direction of the middle core portion 4. The area of ​​the elastic body 10 is the area of ​​the surface of the elastic body 10 in a compressed state that faces the middle core portion 4. The cross-sectional area of ​​the middle core portion 4 is the part shown by the diagonal hatching slanting downward to the left in the lower diagram of Fig. 4. The area of ​​the elastic body 10 is the part shown by the diagonal hatching slanting downward to the right in the lower diagram of Fig. 4.

[0080] The second area ratio in the compressed state being 70% or more means that the elastic body 10 is provided in a certain range of the cross-sectional area of ​​the middle core portion 4. By providing the elastic body 10 in a certain range of the cross-sectional area of ​​the middle core portion 4, the load applied to the middle core portion 4 is easily absorbed by the elastic body 10 during the manufacturing process of the reactor 1, and cracks are less likely to occur in the magnetic core 3. Since cracks are less likely to occur in the magnetic core 3 during the manufacturing process of the reactor 1, a reactor 1 with fewer cracks in the magnetic core 3 can be obtained. The larger the second area ratio, the easier it is for the elastic body 10 to absorb the load. For example, the elastic body 10 in the compressed state may slightly protrude from the middle core portion 4. In this case, the second area ratio is more than 100%. By having the second area ratio more than 100%, the compressed elastic body 10 is disposed over the entire cross-section of the middle core portion 4 during the manufacturing process of the reactor 1, and the load is easily absorbed by the elastic body 10. If the second area ratio is too large, the constituent resin of the molded resin portion 9 becomes difficult to flow during the manufacturing process of the reactor 1. Therefore, the second area ratio is preferably 110% or less. The second area ratio is preferably 70% or more and 110% or less, more preferably 80% or more and 110% or less, and particularly preferably 80% or more and 100% or less. If the second area ratio is less than 100%, the constituent resin of the molded resin portion 9 is configured around the elastic body 10. In this case, the elastic body 10 and the constituent resin of the molded resin portion 9 configure the gap material.

[0081] The thickness of the elastic body 10 in the compressed state can be appropriately selected so as to maintain a desired inductance. The thickness of the elastic body 10 is, for example, 0.2 mm or more and 2.0 mm or less, further 0.3 mm or more and 2.0 mm or less, and particularly 0.3 mm or more and 1.5 mm or less.

[0082] The elastic body 10 has heat resistance to such an extent that it is not dissolved or deformed by the unsolidified constituent resin of the molded resin portion 9 when the molded resin portion 9 is formed. For example, the elastic body 10 has a heat resistance temperature of 150° C. or higher. The elastic body 10 has elasticity to such an extent that it is compressed by the pressure when the molded resin portion 9 is formed. The elastic body 10 has a Young's modulus of 1 MPa or more and 100 MPa or less. The elastic body 10 has excellent thermal conductivity. For example, the elastic body 10 has a thermal conductivity of 0.8 W / m·K or more. The elastic body 10 is non-magnetic. 。 The elastic body 10 has insulating properties. Examples of the material constituting the elastic body 10 include silicone rubber, butyl rubber, etc. Alternatively, the elastic body 10 may be a sheet made of polytetrafluoroethylene (PTFE) resin.

[0083] <Other> Although not shown, the reactor 1 may include a holding member and an adhesive layer. The holding member is interposed between the coil 2 and the magnetic core 3, and has a function of ensuring electrical insulation between the coil 2 and the magnetic core 3. The holding member also has a function of defining the relative positions of the coil 2 and the magnetic core 3 and maintaining the positioning state. The holding member is disposed, for example, between the end face of the winding portion 20 and the end core portions 7 and 8. The holding member is disposed, for example, between the inner peripheral surface of the winding portion 20 and the outer peripheral surface of the middle core portion 4. The holding member disposed between the inner peripheral surface of the winding portion 20 and the outer peripheral surface of the middle core portion 4 is structured so that the unsolidified constituent resin of the molded resin portion 9 can flow between the winding portion 20 and the middle core portion 4. The adhesive layer fixes the assembly including the coil 2, the magnetic core 3, and the elastic body 10 to the installation surface.

[0084] <Reactor manufacturing method> A method for manufacturing a reactor will be described with reference to Figures 5 to 7. The method for manufacturing a reactor includes a preparation step and a molding step.

[0085] [Preparation process] In the preparation step, as shown in FIG. 5, an assembly including the coil 2, the magnetic core 3, and the elastic body 10α is prepared.

[0086] The coil 2 has one winding portion 20. The coil 2 is similar to the coil 2 in the obtained reactor 1. The coil 2 shown in FIG. 5 is the same as the coil 2 shown in FIG.

[0087] The magnetic core 3 includes a first core piece 31 and a second core piece 32 that are combined with each other. The magnetic core 3 is configured to have a shape of approximately θ as a whole by combining the first core piece 31 and the second core piece 32. The first core piece 31 and the second core piece 32 are the same as the first core piece 31 and the second core piece 32 in the reactor 1 obtained. The shapes of the first core piece 31 and the second core piece 32 shown in FIG. 5 are the same as the first core piece 31 and the second core piece 32 shown in FIG. 1. The magnetic core 3 in the state in which the first core piece 31 and the second core piece 32 are combined includes a middle core portion 4, two side core portions 5, 6, and two end core portions 7, 8. The middle core portion 4 has a portion that is arranged inside the winding portion 20. Each of the two side core portions 5, 6 is arranged side by side with the middle core portion 4 outside the winding portion 20. Each of the two end core portions 7, 8 is disposed so as to connect the middle core portion 4 and the two side core portions 5, 6 on the outside of the end portion of the winding portion 20. At least one of the first core piece 31 and the second core piece 32 is formed of a molded body of a composite material.

[0088] In the magnetic core 3 during the manufacturing process, an elastic body 10α, which will be described later, is provided between the first middle core portion 41 and the second middle core portion 42. In other words, the middle core portion 4 during the manufacturing process is divided midway by the elastic body 10α. The thickness W2 (FIG. 6) of the elastic body 10α is thicker than the thickness W1 (FIG. 3) of the elastic body 10 of the reactor 1 shown in FIG. 1. Therefore, the distance between the first middle core portion 41 and the second middle core portion 42 during the manufacturing process is larger than the distance between the first middle core portion 41 and the second middle core portion 42 in the reactor 1 to be obtained. In the magnetic core 3 during the manufacturing process, a gap 15 is formed between the first side core portion 51 and the second side core portion 52. Similarly, in the magnetic core 3 during the manufacturing process, a gap 15 is formed between the first side core portion 61 and the second side core portion 62.

[0089] The first area ratio in the elastic body 10α in the uncompressed state is 45% or more. The first area ratio is the ratio of the area of ​​the elastic body 10α to the specific area. The specific area is calculated by multiplying the length A and the length B shown in FIG. 6, that is, length A x length B. The specific area shown in FIG. 6 is the same as the specific area shown in FIG. 4. The area of ​​the elastic body 10α is the area of ​​the surface facing the middle core portion 4 in the elastic body 10α in the uncompressed state, that is, before compression. The specific area is the portion shown by the diagonal hatching slanting down to the left in the lower diagram of FIG. 6. The area of ​​the elastic body 10α is the portion shown by the diagonal hatching slanting down to the right in the lower diagram of FIG. 6.

[0090] The specific area is an area that is easily affected by the pressure applied when forming the molded resin portion 9 in the manufacturing process of the reactor 1. The fact that the first area ratio before compression is 45% or more means that the elastic body 10α before compression is provided in a certain range of the specific area. By providing the elastic body 10α before compression in a certain range where the above pressure is applied, the load applied to the middle core portion 4 in the manufacturing process of the reactor 1 is easily absorbed by the elastic body 10α, and cracks are less likely to occur in the magnetic core 3. The larger the first area ratio, the easier it is for the elastic body 10α to absorb the above load. The elastic body 10α compresses under the above load and spreads radially from the center side of the middle core portion 4 outward. If the first area ratio is too large, the elastic body 10α spreads until it reaches the inner circumferential surface of the winding portion 20. When the elastic body 10α reaches the inner circumferential surface of the winding portion 20, the gap between the middle core portion 4 and the winding portion 20 is divided in the axial direction of the winding portion 20 by sandwiching the elastic body 10α. As a result, there is a risk that elastic body 10α may hinder the flow of unsolidified constituent resin of molded resin portion 9. The first area ratio may be 80% or less. The first area ratio may be 45% or more and 80% or less, further 60% or more and 80% or less, particularly 70% or more and 80% or less.

[0091] The second area ratio in the elastic body 10α in the uncompressed state is 75% or more. The second area ratio is the ratio of the area of ​​the elastic body 10α to the cross-sectional area of ​​the middle core portion 4. The fact that the second area ratio before compression is 75% or more means that the elastic body 10α is provided in a certain range of the cross-sectional area of ​​the middle core portion 4. By providing the elastic body 10α in a certain range of the cross-sectional area of ​​the middle core portion 4, the load applied to the middle core portion 4 during the manufacturing process of the reactor 1 can be easily absorbed by the elastic body 10α, and cracks are less likely to occur in the magnetic core 3. The larger the second area ratio, the easier it is for the elastic body 10α to absorb the load. The elastic body 10α compresses under the load and spreads radially from the center side of the middle core portion 4 outward. If the second area ratio is too large, the elastic body 10α spreads until it reaches the inner circumferential surface of the winding portion 20. When the elastic body 10α reaches the inner peripheral surface of the winding portion 20, the gap between the middle core portion 4 and the winding portion 20 is divided in the axial direction of the winding portion 20, sandwiching the elastic body 10α. As a result, there is a risk that the elastic body 10α will hinder the flow of the unsolidified constituent resin of the molded resin portion 9. Therefore, as shown in Fig. 7, the second area ratio is preferably 95% or less. The second area ratio is preferably 75% or more and 95% or less, further preferably 80% or more and 95% or less, and particularly preferably 85% or more and 95% or less.

[0092] The thickness of the elastic body 10α in an uncompressed state can be appropriately selected so that the load can be absorbed when the elastic body 10α is compressed in a molding process described later, and the desired inductance can be maintained by the compressed elastic body 10α. The thickness of the elastic body 10α is, for example, 0.2 mm to 2.0 mm, further 0.3 mm to 1.9 mm, and particularly 0.3 mm to 1.4 mm.

[0093] [Molding process] In the molding process, as shown in Fig. 5, the assembly is placed in a mold 100, and resin is injected into the mold 100 to form a molded resin portion 9 (Fig. 1) so as to cover at least a portion of the magnetic core 3. The resin is injected with a pressure of 15 MPa or more in the direction in which the two end core portions 7, 8 approach each other, that is, in the direction of the outlined arrows shown in Fig. 5. The pressure is the injection pressure when injecting the resin. After the resin is filled into the mold, the assembly may be held by applying a certain pressure to prevent the resin from flowing back from the gate. The holding pressure at this time may also be 15 MPa or more.

[0094] The pressure causes the first core laminations 31 and the second core laminations 32 to approach each other, and the elastic bodies 10α are compressed. The pressure also causes the first core laminations 31 and the second core laminations 32 to approach each other, the first side core portions 51 and the second side core portions 52 to come into direct contact with each other, and the first side core portions 61 and the second side core portions 62 to come into direct contact with each other. In other words, the gap 15 shown in Fig. 5 disappears. In this state, the resin is solidified to obtain the reactor 1 shown in Fig. 1.

[0095] Effect In the manufacturing method of the reactor of the first embodiment, even if a high pressure of 15 MPa or more is applied when forming the molded resin portion 9, the magnetic core 3 is unlikely to crack. When an assembly including the coil 2, the magnetic core 3, and the elastic body 10α is placed in the mold 100 and resin is injected into the mold 100 to form the molded resin portion 9, pressure is applied in a direction in which the two end core portions 7 and 8 approach each other. In the manufacturing method of the reactor of the first embodiment, the elastic body 10α is provided in the middle of the middle core portion 4, which is easily affected by the pressure, so that the load due to the pressure can be absorbed by the elastic body 10α, and the magnetic core 3 is unlikely to crack. Since the magnetic core 3 is unlikely to crack during the manufacturing process, the obtained reactor 1 of the first embodiment has few cracks in the magnetic core 3.

[0096] <Embodiment 2> The reactor 1 of the second embodiment will be described with reference to Fig. 8. The reactor 1 of the second embodiment differs from the reactor 1 of the first embodiment in the shapes of the first core laminations 31 and the second core laminations 32 that constitute the magnetic core 3. In the following description, the differences from the above-mentioned first embodiment will be mainly described, and the description of the similar points will be omitted.

[0097] The first core piece 31 of this example includes an end core piece 7, a first middle core piece 41, and two side core pieces 5 and 6. The first middle core piece 41 is a part of the middle core piece 4. The length of the first middle core piece 41 along the first direction D1 is shorter than the length of the two side core pieces 5 and 6 along the first direction D1. Therefore, the first core piece 31 of this example is an E-shaped member in which the length of the first middle core piece 41 is shorter than the length of the two side core pieces 5 and 6. The second core piece 32 of this example includes an end core piece 8 and a second middle core piece 42. The second middle core piece 42 is the remaining part of the middle core piece 4. The second core piece 32 of this example is a T-shaped member. The magnetic core 3 is configured to be θ-shaped as a whole by combining the E-shaped first core piece 31 and the T-shaped second core piece 32. An elastic body 10 is provided between the first middle core piece 41 and the second middle core piece 42. In other words, the middle core portion 4 of this example is divided midway by the elastic body 10. The two side core portions 5, 6 and the end core portion 8 are in direct contact with each other and are thus configured as a continuous piece without being divided.

[0098] As in the first embodiment, the reactor 1 of the second embodiment also has an elastic body 10 provided in the middle of the middle core portion 4, so that the pressure applied during the manufacturing process of the reactor 1 can be absorbed by the elastic body 10, and the magnetic core 3 is less likely to crack.

[0099] <Embodiment 3> A reactor 1 of embodiment 3 will be described with reference to Fig. 9. The reactor 1 of embodiment 3 differs from the reactor 1 of embodiment 1 in the shapes of the first core laminations 31 and the second core laminations 32 that configure the magnetic core 3. In the following description, the differences from embodiment 1 described above will be mainly described, and descriptions of similar points will be omitted.

[0100] The first core piece 31 of this example includes an end core piece 7, a middle core piece 4, and two side core pieces 5 and 6. The first core piece 31 of this example is an E-shaped member. The second core piece 32 of this example includes an end core piece 8. The second core piece 32 of this example is an I-shaped member. The magnetic core 3 is configured to have a θ shape as a whole by combining the E-shaped first core piece 31 and the I-shaped second core piece 32. An elastic body 10 is provided between the middle core piece 4 and the end core piece 8. In other words, in this example, the boundary between the middle core piece 4 and the end core piece 8 is divided by the elastic body 10. The two side core pieces 5 and 6 and the end core piece 8 are directly in contact with each other, and are configured as a continuous piece without being divided.

[0101] As in embodiment 1, the reactor 1 of embodiment 3 also has an elastic body 10 provided at the end of the middle core portion 4, which allows the elastic body 10 to absorb the pressure applied during the manufacturing process of the reactor 1, making it less likely that the magnetic core 3 will crack.

[0102] <Embodiment 4> A reactor 1 of the fourth embodiment will be described with reference to Fig. 10. The reactor 1 of the fourth embodiment differs from the reactor 1 of the first embodiment in the shapes of the first core laminations 31 and the second core laminations 32 that constitute the magnetic core 3. In the following description, the differences from the first embodiment described above will be mainly described, and descriptions of similar points will be omitted.

[0103] The first core piece 31 of this example includes an end core piece 7, a middle core piece 4, and two first side core pieces 51, 61. The first side core piece 51 is a part of the side core piece 5. The first side core piece 61 is a part of the side core piece 6. The length of the middle core piece 4 along the first direction D1 is longer than the length of the two first side core pieces 51, 61 along the first direction D1. Therefore, the first core piece 31 of this example is an E-shaped member in which the length of the middle core piece 4 is longer than the length of the two first side core pieces 51, 61. The second core piece 32 of this example includes an end core piece 8 and two second side core pieces 52, 62. The second side core piece 52 is the remaining part of the side core piece 5. The second side core piece 62 is the remaining part of the side core piece 6. The second core piece 32 of this example is a U-shaped member. The magnetic core 3 is configured to be θ-shaped as a whole by combining an E-shaped first core piece 31 and a U-shaped second core piece 32. An elastic body 10 is provided between the middle core portion 4 and the end core portion 8. In other words, in this example, the boundary between the middle core portion 4 and the end core portion 8 is divided by the elastic body 10. The first side core portion 51 and the second side core portion 52 are configured to be continuous without being divided by being in direct contact with each other. In addition, the first side core portion 61 and the second side core portion 62 are configured to be continuous without being divided by being in direct contact with each other. The end core portion 7 and the middle core portion 4 are an integrally molded body.

[0104] As in embodiment 1, the reactor 1 of embodiment 4 also has an elastic body 10 provided at the end of the middle core portion 4, which allows the elastic body 10 to absorb the pressure applied during the manufacturing process of the reactor 1, making it less likely that the magnetic core 3 will crack.

[0105] <Embodiment 5> A reactor 1 of embodiment 5 will be described with reference to Fig. 11. The reactor 1 of embodiment 5 differs from the reactor 1 of embodiment 1 in the shapes of the first core laminations 31 and the second core laminations 32 that configure the magnetic core 3. In the following description, the differences from embodiment 1 described above will be mainly described, and descriptions of similar points will be omitted.

[0106] The first core piece 31 of this example includes two end core pieces 7, 8 and two side core pieces 5, 6. The two end core pieces 7, 8 and the two side core pieces 5, 6 are integrally molded into one piece. The first core piece 31 of this example is an O-shaped member. The second core piece 32 of this example includes a middle core piece 4. The second core piece 32 of this example is an I-shaped member. The magnetic core 3 is configured to have a θ shape as a whole by combining the O-shaped first core piece 31 and the I-shaped second core piece 32. An elastic body 10 is provided between the middle core piece 4 and the end core piece 7. In other words, in this example, the boundary between the middle core piece 4 and the end core piece 7 is divided by the elastic body 10. Similarly, an elastic body 10 is provided between the middle core piece 4 and the end core piece 8. In other words, in this example, the boundary between the middle core piece 4 and the end core piece 8 is divided by the elastic body 10. In this example, the elastic body 10 is provided so as to divide both the boundaries between the middle core portion 4 and the end core portions 7, 8. Alternatively, the elastic body 10 may be provided so as to divide only the boundary between the middle core portion 4 and the end core portion 7. In this case, at the boundaries between the middle core portion 4 and the end core portion 8 where the elastic body 10 is not provided, the middle core portion 4 and the end core portion 8 are in direct contact with each other, and are thus formed as a continuous portion without being divided.

[0107] As in embodiment 1, the reactor 1 of embodiment 5 also has an elastic body 10 provided at the end of the middle core portion 4, so that the pressure applied during the manufacturing process of the reactor 1 can be absorbed by the elastic body 10, making it less likely that the magnetic core 3 will crack.

[0108] <Embodiment 6> The reactors according to the first to fifth embodiments can be used for applications that satisfy the following energization conditions. For example, the energization conditions include a maximum DC current of about 100 A to 1000 A, an average voltage of about 100 V to 1000 V, and a usage frequency of about 5 kHz to 100 kHz. The reactors according to the first to fifth embodiments can be used as components of converters mounted on vehicles such as electric vehicles and hybrid vehicles, and as components of power conversion devices equipped with these converters.

[0109] 12, 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 that 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. Although FIG. 12 shows an inlet as a charging point for the vehicle 1200, a form including a plug may also be used.

[0110] 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 the voltage to the inverter 1120. When regenerating, the converter 1110 reduces 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 direct current boosted by the converter 1110 to a predetermined alternating current and supplies the motor 1220 with power, and when regenerating, converts the alternating current output from the motor 1220 to a direct current and outputs the direct current to the converter 1110.

[0111] As shown in FIG. 13, the converter 1110 includes a plurality of switching elements 1111, a drive circuit 1112 that controls the operation of the switching elements 1111, and a reactor 1115, and converts the input voltage by repeatedly turning the switching elements 1111 on and off. The conversion of the input voltage means stepping up and down the voltage here. The switching elements 1111 include power devices such as field effect transistors and insulated gate bipolar transistors. The reactor 1115 has a function of smoothing the change when the current increases or decreases due to the switching operation by utilizing the property of a coil that prevents the change in the current flowing through the circuit. The reactor 1115 includes any one of the reactors 1 according to the first to fifth embodiments. By including a reactor with fewer cracks in the magnetic core, the power conversion device 1100 and the converter 1110 can be expected to have low loss.

[0112] In addition to the converter 1110, the vehicle 1200 includes a converter 1150 for a power supply device connected to the main battery 1210, and a converter 1160 for an auxiliary power supply connected to a sub-battery 1230 serving as a power source for the auxiliary devices 1240 and the main battery 1210 to convert the high voltage of the main battery 1210 to a low voltage. The converter 1110 typically performs DC-DC conversion, while the converter 1150 for a power supply device and the converter 1160 for an auxiliary power supply perform AC-DC conversion. Some of the converters 1150 for a power supply device perform DC-DC conversion. The reactors of the converter 1150 for a power supply device and the converter 1160 for an auxiliary power supply may have the same configuration as the reactor 1 of any one of the first to fifth embodiments, and may be appropriately changed in size, shape, and the like. The reactor 1 of any one of the first to fifth embodiments may also be used as a converter that converts input power and that performs only step-up or step-down. [Explanation of symbols]

[0113] 1 Reactor 2 coils, 20 turns 3 magnetic core, 31 first core piece, 32 second core piece 4. Middle Core Section 41 First Middle Core Section, 42 Second Middle Core Section 5,6 Side core part 51, 61: first side core portion; 52, 62: second side core portion 7,8 End core section 9 Molded resin part 10,10α Elastic body, 15 Gap 100 Molds A,B length, W1,W2 thickness D1 first direction, D2 second direction, D3 third direction 1100 Power conversion device, 1110 Converter, 1111 Switching element 1112 Drive circuit, 1115 Reactor, 1120 Inverter 1150 Converter for power supply device, 1160 Converter for auxiliary power supply 1200 vehicle, 1210 main battery, 1220 motor 1230 Sub-battery, 1240 Auxiliary equipment, 1250 Wheels, 1300 Engine

Claims

1. The coil includes a magnetic core, a molded resin portion, and an elastic body. the coil comprises one turn; The magnetic core includes first core pieces and second core pieces that are combined with each other, At least one of the first core pieces and the second core pieces is formed of a composite material molded body in which soft magnetic powder is dispersed in a resin, The magnetic core in a state in which the first core piece and the second core piece are combined includes a middle core piece, two side core pieces, and two end core pieces, the middle core portion has a portion disposed inside the winding portion, Each of the two side core portions is disposed next to the middle core portion on the outer side of the winding portion, each of the two end core portions is disposed so as to connect the middle core portion and the two side core portions to the outside of an end portion of the winding portion; the molded resin portion covers at least a portion of the magnetic core so as to be disposed between an inner circumferential surface of the winding portion and an outer circumferential surface of the middle core portion, the elastic body is provided so as to divide at least one of a middle portion of the middle core portion and a boundary between the middle core portion and the end core portion, a ratio of an area of ​​the elastic body to a cross-sectional area of ​​the middle core portion is more than 100% and not more than 110%; the cross-sectional area of ​​the middle core portion is an area of ​​a cross section obtained by cutting the middle core portion in a direction perpendicular to the longitudinal direction of the middle core portion, The area of ​​the elastic body is the area of ​​a surface of the elastic body in a compressed state that faces the middle core portion. Reactor.

2. The reactor according to claim 1 , wherein the two side core portions and the two end core portions are configured as a single unit.

3. The ratio of the area of ​​the elastic body to the specific area is 70% or more, The specific area is calculated by length A x length B, the length A is a length of the middle core portion along a direction perpendicular to both a longitudinal direction of the middle core portion and a direction in which the middle core portion and the two side core portions are arranged side by side, The length B is the length between the inner surfaces of the two side core portions, 3. The reactor according to claim 1, wherein the area of ​​the elastic body is an area of ​​a surface of the elastic body in a compressed state that faces the middle core portion.

4. The reactor according to claim 1 , wherein the elastic body is made of silicone rubber or butyl rubber.

5. 5. The reactor according to claim 1, wherein each of the first core lamination and the second core lamination is an E-shaped member including one of the two end core portions, a portion of the middle core portion, and a portion of each of the two side core portions.

6. the first core piece is an E-shaped member including one of the two end core pieces, a part of the middle core piece, and each of the two side core pieces, The reactor according to claim 1 , wherein the second core lamination is a T-shaped member including the other of the two end core portions and a remaining portion of the middle core portion.

7. the first core piece is an E-shaped member including one of the two end core portions, the middle core portion, and each of the two side core portions, The reactor according to claim 1 , wherein the second core lamination is an I-shaped member including the other of the two end core portions.

8. the first core piece is an E-shaped member including one of the two end core pieces, the middle core piece, and a portion of each of the two side core pieces, The reactor according to claim 1 , wherein the second core lamination is a U-shaped member including the other of the two end core portions and each of the remaining portions of the two side core portions.

9. the first core piece is an O-shaped member including each of the two end core portions and each of the two side core portions, The reactor according to claim 1 , wherein the second core lamination is an I-shaped member including the middle core portion.

10. A reactor comprising the reactor according to any one of claims 1 to 9. converter.

11. A converter comprising: Power conversion equipment.

12. preparing an assembly including a coil, a magnetic core, and an elastic body; and placing the assembly in a mold and injecting a resin into the mold to form a molded resin portion so as to cover at least a portion of the magnetic core. the coil comprises one turn; The magnetic core includes first core pieces and second core pieces that are combined with each other, At least one of the first core pieces and the second core pieces is formed of a composite material molded body in which soft magnetic powder is dispersed in a resin, The magnetic core in a state in which the first core piece and the second core piece are combined includes a middle core piece, two side core pieces, and two end core pieces, the middle core portion has a portion disposed inside the winding portion, Each of the two side core portions is disposed next to the middle core portion on the outer side of the winding portion, each of the two end core portions is disposed so as to connect the middle core portion and the two side core portions to the outside of an end portion of the winding portion; In the preparing step, the elastic body is disposed so as to divide at least one of the middle core portion and the boundary between the middle core portion and the end core portion, In the step of forming the molded resin portion, a pressure of 15 MPa or more is applied in a direction in which the two end core portions approach each other. A method for manufacturing a reactor.

13. In the preparing step, a non-compressed elastic body having an area of ​​45% or more of a specific area is arranged, The specific area is calculated by length A x length B, the length A is a length of the middle core portion along a direction perpendicular to both a longitudinal direction of the middle core portion and a direction in which the middle core portion and the two side core portions are arranged side by side, The method for manufacturing a reactor according to claim 12 , wherein the length B is a length between inner surfaces of the two side core portions.

14. In the preparing step, a non-compressed elastic body having an area of ​​75% to 95% of a cross-sectional area of ​​the middle core portion is disposed, The method for manufacturing a reactor according to claim 12 or 13, wherein the cross-sectional area of ​​the middle core portion is an area of ​​a cross section of the middle core portion cut in a direction perpendicular to a longitudinal direction of the middle core portion.

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