Reactor, converter, and power conversion device

Abstract

A reactor includes a coil having a first winding portion and a magnetic core having an intermediate core, a first end core, a second end core, a first side core, and a second side core. The first end core includes a first outer surface located at a position apart from the first end surface in an X direction, and a first recess provided to the first outer surface. The first recess is provided to a middle portion in a Y direction in the first end core when the magnetic core is viewed from a Z direction. The X direction is a direction along an axial direction of the intermediate core. The Y direction is a direction in which the intermediate core, the first side core, and the second side core are arranged in parallel. The Z direction is a direction orthogonal to the X direction and the Y direction.

Description

TECHNICAL FIELD

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

[0002] This application claims priority based on Japanese Patent Application No. 2020-059195 filed on March 27, 2020, and incorporates by reference the entire disclosure of the Japanese Patent Application. BACKGROUND

[0003] A reactor is a component of a converter provided in a hybrid vehicle or the like. The reactor includes a coil having a winding portion in which a wire is wound in a spiral shape, and a magnetic core assembled to the coil. For example, Patent Literature 1 discloses a reactor in which the number of winding portions is one. The magnetic core of the reactor has an intermediate core disposed inside the winding portion, a side core disposed outside a peripheral surface of the winding portion, and an end core disposed at an end surface of the winding portion. Figures 5 to 8

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2016-201509 SUMMARY

[0007] The reactor of the present disclosure includes a coil and a magnetic core,

[0008] The coil has a first winding portion,

[0009] The magnetic core includes:

[0010] an intermediate core disposed inside the first winding portion;

[0011] a first end core facing a first end surface of the first winding portion;

[0012] a second end core facing a second end surface of the first winding portion;

[0013] a first side core disposed outside a first side surface of the first winding portion, connecting the first end core and the second end core; and

[0014] a second side core disposed outside a second side surface of the first winding portion, connecting the first end core and the second end core,

[0015] The first end core includes:

[0016] a first outer surface located at a position apart from the first end surface in an X direction; and

[0017] a first recess portion provided to the first outer surface, ​

[0018] The first recess is provided at a middle portion in the Y direction in the first end core when the magnetic core is viewed from the Z direction,

[0019] The X direction is a direction along an axial direction of the middle core,

[0020] The Y direction is a direction in which the middle core, the first side core, and the second side core are arranged side by side,

[0021] The Z direction is a direction orthogonal to the X direction and the Y direction.

[0022] The converter of the present disclosure,

[0023] The reactor of the present disclosure.

[0024] The power conversion device of the present disclosure,

[0025] The converter of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic perspective view of the reactor of Embodiment 1.

[0027] Figure 2 is a plan view of the reactor of Figure 1 .

[0028] Figure 3 is a plan view of the reactor shown in Embodiment 2.

[0029] Figure 4 is a plan view of the reactor shown in Embodiment 3.

[0030] Figure 5 is a plan view of the reactor shown in Embodiment 4.

[0031] Figure 6 is a configuration view schematically showing a power supply system of a hybrid vehicle.

[0032] Figure 7 is a circuit diagram showing an outline of an example of a power conversion device provided with a converter.

[0033] Figure 8 is a graph showing a relationship between a width of the first recess and a deterioration rate of the inductance in Test Example 1.

[0034] Figure 9 is a graph showing a relationship between a width of the first recess and a deterioration rate of the total loss in Test Example 1.

[0035] Figure 10 is a graph showing a relationship between a depth of the first recess and a deterioration rate of the inductance in Test Example 2.

[0036] Figure 11 FIG. 8 is a graph showing the relationship between the depth of the first recess and the deterioration rate of the total loss in Test Example 2. DETAILED DESCRIPTION

[0037] [Problems to be Solved by the Present Disclosure]

[0038] With the development of hybrid cars and the like, there is a demand for a lighter reactor. However, when the magnetic core is downsized in order to achieve a lighter reactor, the magnetic characteristics of the reactor deteriorate.

[0039] Therefore, it is an object of the present disclosure to provide a reactor that is light and has excellent magnetic characteristics. In addition, it is an object of the present disclosure to provide a converter and a power conversion device that have a reactor that is light and has excellent magnetic characteristics.

[0040] [Effects of the Present Disclosure]

[0041] The reactor of the present disclosure is light and has excellent magnetic characteristics. In addition, the converter and the power conversion device of the present disclosure are light and have excellent conversion efficiency.

[0042] [Explanation of Embodiments of the Present Disclosure]

[0043] First, an embodiment of the present disclosure will be explained.

[0044] <1> Reactor of the Embodiment,

[0045] having a coil and a magnetic core,

[0046] the coil having a first winding portion,

[0047] the magnetic core having:

[0048] an intermediate core disposed inside the first winding portion;

[0049] a first end core facing a first end surface of the first winding portion;

[0050] a second end core facing a second end surface of the first winding portion;

[0051] a first side core disposed outside a first side surface of the first winding portion, connecting the first end core and the second end core; and

[0052] a second side core disposed outside a second side surface of the first winding portion, connecting the first end core and the second end core,

[0053] the first end core having:

[0054] a first outer surface located at a position apart from the first end surface in the X direction; and

[0055] a first recess is provided in the first outer surface,

[0056] The first recess is provided in a Y-direction intermediate portion in the first end core when the magnetic core is viewed from a Z-direction,

[0057] The X-direction is a direction along an axial direction of the intermediate core,

[0058] The Y-direction is a direction in which the intermediate core, the first side core, and the second side core are arranged side by side,

[0059] The Z-direction is a direction orthogonal to the X-direction and the Y-direction.

[0060] By providing the first recess in the first end core, the solid portion of the first end core is reduced, so the weight of the reactor is reduced compared to a case where the first recess is not provided.

[0061] The Y-direction intermediate portion in the first outer surface of the first end core is a portion through which magnetic flux is difficult to pass. Therefore, by providing the first recess in the Y-direction intermediate portion in the first outer surface of the first end core, it is possible to suppress a decrease in the magnetic characteristics of the reactor due to the provision of the first recess in the magnetic core. Here, the intermediate portion refers to a region in the Y-direction of the first end core that does not overlap with the side cores.

[0062] <2> As one mode of the reactor according to the embodiment, there can be mentioned a mode in which

[0063] The first recess is housed within the range of the Y-direction length in the intermediate core when the magnetic core is viewed from the Z-direction.

[0064] By housing the width of the first recess within the range of the width of the intermediate core, it is easy to suppress a decrease in the magnetic characteristics of the reactor due to the provision of the first recess in the magnetic core.

[0065] <3> As one mode of the reactor according to the embodiment, there can be mentioned a mode in which

[0066] The first recess is a groove shape extending in the Z-direction.

[0067] When the first recess is a groove shape extending in the Z-direction, by lengthening the Z-direction length of the first recess, it is easy to suppress a decrease in the magnetic characteristics of the reactor even if the amount of reduction of the first end core based on the first recess is large. This is because: even if the Z-direction length of the first recess is lengthened, the first recess is housed in a portion through which magnetic flux is difficult to pass in the first end core. When the first recess is a groove shape extending in the Y-direction, it is possible that the first recess reduces a portion through which magnetic flux passes more when the Y-direction length of the first recess is lengthened.

[0068] <4> As one mode of the reactor of the embodiment, there can be mentioned a mode in which

[0069] The cross-sectional shape of the first recess portion in the Z direction is rectangular

[0070] The first recess portion having a rectangular or trapezoidal cross-sectional shape is easy to form. In addition, in the case where the first end core is produced by being compressed in the X direction, an effect of easily pulling out the first end core from a mold can be obtained.

[0071] <5> As one mode of the reactor of the embodiment, there can be mentioned a mode in which

[0072] The magnetic core includes a plurality of core pieces,

[0073] One of the plurality of core pieces is a first core piece including at least the first end core,

[0074] The first core piece is a press powder molded body including a raw material powder of a soft magnetic powder.

[0075] The magnetic core is composed of a plurality of core pieces, so that the magnetic core can be assembled after the coil having the winding portion. In addition, when the first core piece including the first recess portion is a press powder molded body, as compared with the case where the first core piece is a molded body of a composite material, it is easy to suppress a decrease in magnetic characteristics of the magnetic core.

[0076] <6> As one mode of the reactor of the embodiment, there can be mentioned a mode in which

[0077] When the magnetic core is viewed from the Z direction,

[0078] The width of the first recess portion in the Y direction is 5% or more and 50% or less of the length of the first end core in the Y direction.

[0079] When the width of the first recess portion in the Y direction is 5% or more and 50% or less of the length of the first end core in the Y direction, the portion where the magnetic flux passes through in the first end core and the first recess portion do not easily overlap. Therefore, it is easy to suppress a decrease in magnetic characteristics of the reactor.

[0080] <7> As one mode of the reactor of the embodiment, there can be mentioned a mode in which

[0081] When the magnetic core is viewed from the Z direction,

[0082] The width of the first recess portion in the Y direction is 10% or more and 150% or less of the length of the intermediate core in the Y direction.

[0083] When the width in the Y direction in the first recess portion is 10% or more and 150% or less of the length in the Y direction in the intermediate core, the first recess portion and the portion in the first end core through which the magnetic flux passes more easily do not easily overlap. Thus, it is easy to suppress a decrease in the magnetic characteristic of the reactor.

[0084] <8> As one mode of the reactor of the embodiment, there can be cited a reactor in which

[0085] When the magnetic core is viewed from the Z direction,

[0086] The depth in the X direction of the first recess portion is 10% or more and 125% or less of the length in the X direction of the first end core.

[0087] When the depth in the X direction in the first recess portion is 10% or more and 125% or less of the length in the X direction in the first end core, the first recess portion and the portion in the first end core through which the magnetic flux passes more easily do not easily overlap. Thus, it is easy to suppress a decrease in the magnetic characteristic of the reactor. Here, in the case where the depth of the first recess portion is 100% or more of the length in the X direction of the first end core, the first recess portion reaches the intermediate core. In this case, the width of the first recess portion needs to be smaller than the length in the Y direction of the intermediate core.

[0088] <9> As one mode of the reactor of the embodiment, there can be cited a reactor in which

[0089] The second end core includes:

[0090] a second outer surface located at a position apart from the second end surface in the X direction; and

[0091] a second recess portion provided to the second outer surface,

[0092] When the magnetic core is viewed from the Z direction, the second recess portion is provided to an intermediate portion in the Y direction in the second end core

[0093] In addition to the first recess portion provided to the first end core, a second recess portion is provided to the second end core, whereby the reactor is further lightened.

[0094] Here, the preferred structure of the second recess portion is the same as the preferred structure of the first recess portion. That is, the preferred structure of the second recess portion is a structure in which "the first recess portion" in the reactors described in <2> to <8> above is read as "the second recess portion".

[0095] <10> As one mode of the reactor of the embodiment, there can be cited a reactor in which

[0096] The coil further includes a second winding portion and a third winding portion,

[0097] The first side core is disposed inside the second winding portion,

[0098] The second side core is arranged inside the third winding portion.

[0099] A reactor having three winding portions for a specific purpose tends to be heavy. In such a reactor, the weight of the reactor is reduced by providing the first recessed portion in the first end core.

[0100] <11> Embodiments of the converter,

[0101] Possess the above <1> to <10> Any of the reactors.

[0102] The converter includes the reactor of the embodiment that is lightweight and has excellent magnetic characteristics. Therefore, the converter is lightweight and has excellent conversion efficiency.

[0103] <12> The power conversion device of the embodiment,

[0104] Possess the above <11> converter.

[0105] The power conversion device includes a converter that is lightweight and has excellent conversion efficiency.

[0106] [Details of the embodiments of the present disclosure]

[0107] The following describes an embodiment of the reactor disclosed herein based on the accompanying drawings. Identical reference numerals in the drawings represent identical items. The present invention is not limited to the configurations shown in the embodiments, but is intended to encompass all modifications within the meaning and scope of the claims, which are equivalent to the claims.

[0108] <Implementation Method 1>

[0109] In embodiment 1, based on Figure 1 、 2 The structure of the reactor 1 will be described. Figure 1 The reactor 1 shown is constructed by combining a coil 2 and a magnetic core 3. One of the characteristics of the reactor 1 is that a first recess 4 is provided in a portion of the magnetic core 3. Hereinafter, each structure of the reactor 1 will be described in detail.

[0110] Coil

[0111] The coil 2 has a first winding portion 21 ( Figure 1 、 2The first winding portion 21 is formed by spirally winding a single winding wire without a joint. A known winding wire can be used. This method uses a coated flat wire. The conductor of the coated flat wire is a copper flat wire. The insulating coating of the coated flat wire is made of enamel. The first winding portion 21 is formed by an edgewise coil formed by edgewise winding the coated flat wire.

[0112] The first winding portion 21 is in the shape of a rectangular tube. Rectangle includes a square. That is, the end face of the first winding portion 21 is formed into a rectangular frame shape. Since the first winding portion 21 is in the shape of a rectangular tube, it is easy to increase the contact area between the first winding portion 21 and the object to be installed, compared with the case where the winding portion is cylindrical with the same cross-sectional area. Therefore, the reactor 1 can easily dissipate heat to the object to be installed via the first winding portion 21. On this basis, it is easy to stably install the first winding portion 21 on the object to be installed. The corners of the winding portion 21 are rounded.

[0113] The end portion 2a and the end portion 2b of the first winding portion 21 extend toward the outer peripheral side of the first winding portion 21 at one end side and the other end side in the axial direction of the first winding portion 21, respectively. At the end portion 2a and the end portion 2b of the first winding portion 21, the insulating coating is stripped to expose the conductor wire. The exposed conductor wire is connected to a terminal member not shown in the figure. The coil 2 is connected to an external device through the terminal member. Illustration of the external device is omitted. The external device may include a power supply for supplying power to the coil 2, etc.

[0114] Magnetic Core

[0115] like Figure 2 As shown, the magnetic core 3 includes a middle core 30, a first end core 31, a second end core 32, a first side core 33, and a second side core 34. Figure 2 , the boundaries of each core 30, 31, 32, 33, and 34 are shown by double-dotted lines. The middle core 30 is a portion of the magnetic core 3 that has a portion arranged inside the first winding portion 21. The first end core 31 is a portion of the magnetic core 3 that faces the first end surface 211 of the first winding portion 21. The second end core 32 is a portion of the magnetic core 3 that faces the second end surface 212 of the first winding portion 21. The first side core 33 is a portion of the magnetic core 3 that is arranged outside the first side surface 213 of the first winding portion 21. The second side core 34 is a portion of the magnetic core 3 that is arranged outside the second side surface 214 of the first winding portion 21.

[0116] In the magnetic core 3, a closed magnetic circuit in an annular shape, indicated by a thick dashed line, is formed between the middle core 30, the first end core 31, the first side core 33, and the second end core 32. Furthermore, a closed magnetic circuit in an annular shape, indicated by a thick dashed line, is formed between the middle core 30, the first end core 31, the second side core 34, and the second end core 32.

[0117] Here, a direction in the reactor 1 is defined with the magnetic core 3 as a reference. First, a direction along the axial direction of the middle core 30 is the X direction. A direction orthogonal to the X direction and in which the middle core 30, the first side core 33, and the second side core 34 are arranged side by side is the Y direction. Also, a direction intersecting both the X direction and the Y direction is the Z direction. Figure 1

[0118] [Middle Core]

[0119] The middle core 30 is a portion of the magnetic core 3 that is disposed inside the first winding portion 21 of the coil 2. Therefore, the middle core 30 extends along the axial direction of the first winding portion 21. In the present example, both end portions of the portion of the magnetic core 3 along the axial direction of the first winding portion 21 protrude from the end faces 211, 212 of the first winding portion 21. This protruding portion is also a portion of the middle core 30.

[0120] The shape of the middle core 30 is not particularly limited as long as it is a shape along the inner shape of the first winding portion 21. The middle core 30 of the present example is substantially cuboid.

[0121] [First End Core, Second End Core]

[0122] The first end core 31 and the second end core 32 are larger than the width of the first winding portion 21 in the Y direction. That is, the first end core 31 extends to the outside in the Y direction from the first end face 211 of the first winding portion 21, and the second end core 32 extends to the outside in the Y direction from the second end face 212 of the first winding portion 21.

[0123] The shape of the first end core 31 and the second end core 32 is not particularly limited as long as it is a shape that forms a sufficient magnetic path inside each end core 31, 32. The first end core 31 and the second end core 32 of the present example are substantially cuboid. Of the four corners of the first end core 31 and the second end core 32 viewed in the Z direction, two corners located far from the side cores 33, 34 can also have rounded corners. When the above two corners have rounded corners, the weight of the end cores 31, 32 is reduced. The above two corners are portions through which magnetic flux is difficult to pass. Therefore, even if the above two corners are rounded, the magnetic characteristics of the reactor 1 are not easily reduced.

[0124] The first end core 31 of the present example is provided with a first recess 4 disposed on a first outer surface 310 thereof. The first outer surface 310 is a face of the first end core 31 that is located far from the middle core 30 among two faces orthogonal to the X direction. Due to the first recess 4, the weight of the first end core 31 is reduced. Details of this first recess 4 will be described later.

[0125] [First Side Core, Second Side Core]

[0126] ​The first side core 33 connects the first end core 31 and the second end core 32 outside the first side surface 213 of the first winding portion 21. The axial direction of the first side core 33 is parallel to the axial direction of the middle core 30. The first side surface 213 is a surface of the first winding portion 21 facing the Y direction.

[0127] The second side core 34 connects the first end core 31 and the second end core 32 outside the second side surface 214 of the first winding portion 21. The second side surface 214 is a surface of the first winding portion 21 facing the Y direction and a surface facing the opposite direction of the first side surface 213. The axial direction of the second side core 34 is parallel to the axial direction of the middle core 30. In this example, the axis of the middle core 30, the axis of the first side core 33, and the axis of the second side core 34 are arranged on the XY plane.

[0128] [Division method]

[0129] The magnetic core 3 is composed of a plurality of pieces in a manner that can be fitted to the coil 2. The magnetic core 3 of this example is composed by combining two pieces, a first piece 3A and a second piece 3B. The first piece 3A is composed of the first end core 31 and a portion of the middle core 30. The shape of the first piece 3A viewed from the Z direction is substantially T-shaped. On the other hand, the second piece 3B is composed of the second end core 32, the first side core 33, the second side core 34, and a portion of the middle core 30. The shape of the second piece 3B viewed from the Z direction is substantially E-shaped. Here, the number of divisions of the magnetic core 3 can be three or more as shown in, for example, Embodiment 2.

[0130] The sum of the length in the X direction of the portion of the first piece 3A that is the middle core 30 and the length in the X direction of the portion of the second piece 3B that is the middle core 30 is shorter than the length in the X direction of the first side core 33 or the length in the X direction of the second side core 34. Therefore, a gap portion 3g is formed inside the first winding portion 21 between the first piece 3A and the second piece 3B. The gap portion 3g of this example is an air gap. A gap plate not shown can be sandwiched in the gap portion 3g. Unlike this example, the end surface of the first piece 3A and the end surface of the second piece 3B can also abut inside the first winding portion 21. In that case, a gap portion can also be provided at least one of between the first end core 31 and the first side core 33 and between the first end core 31 and the second side core 34.

[0131] [Magnetic properties, material, etc.]

[0132] Each core 30, 31, 32, 33, 34 of the magnetic core 3 is preferably a powder compact formed by press-molding a raw material powder containing a soft magnetic powder, or a compact of a composite material of a soft magnetic powder and a resin. All of the cores 30, 31, 32, 33, 34 can be powder compacts, or all of the cores 30, 31, 32, 33, 34 can be compacts of a composite material. Alternatively, some of the cores 30, 31, 32, 33, 34 can be powder compacts, and the remaining cores can be compacts of a composite material. The magnetic core 3 in which some of the cores 30, 31, 32, 33, 34 are powder compacts and the remaining cores are compacts of a composite material is less likely to be magnetically saturated.

[0133] The soft magnetic powder of the powder compact is a collection of soft magnetic particles composed of an iron group metal such as iron, or an iron alloy such as a Fe (iron)-Si (silicon) alloy, a Fe-Ni (nickel) alloy, or the like. An insulating coating portion composed of a phosphate or the like can be formed on the surface of the soft magnetic particles. The raw material powder can contain a lubricating material or the like.

[0134] The compact of a composite material can be manufactured by filling a mixture of a soft magnetic powder and an uncured resin into a mold and curing the resin. The soft magnetic powder of the composite material can use the same substance as that used in the powder compact. On the other hand, as the resin included in the composite material, a thermosetting resin, a thermoplastic resin, a room-temperature-curable resin, a low-temperature-curable resin, or the like can be listed. The thermosetting resin can include, for example, an unsaturated polyester resin, an epoxy resin, a urethane resin, a silicone resin, or the like. The thermoplastic resin can include, for example, a polyphenylene sulfide (PPS) resin, a polytetrafluoroethylene (PTFE) resin, a liquid crystal polymer (LCP), a polyamide (PA) resin such as nylon 6 or nylon 66, a polybutylene terephthalate (PBT) resin, an acrylonitrile-butadiene-styrene (ABS) resin, or the like. In addition to these, a BMC (Bulk molding compound) in which calcium carbonate or glass fibers are mixed with an unsaturated polyester, a kneading-type silicone rubber, a kneading-type polyurethane rubber, or the like can be used.

[0135] The composite material described above can further improve heat dissipation when a filler of a non-magnetic and non-metallic powder such as alumina or silica is contained in addition to the soft magnetic powder and the resin. The content of the non-magnetic and non-metallic powder can be 0.2% by mass or more and 20% by mass or less, further 0.3% by mass or more and 15% by mass or less, 0.5% by mass or more and 10% by mass or less.

[0136] The content of the soft magnetic powder in the composite material can be, for example, 30 vol% or more and 80 vol% or less. From the viewpoint of increasing the saturation magnetic flux density and heat dissipation, the content of the soft magnetic powder can be further set to 50 vol% or more, 60 vol% or more, or 70 vol% or more. From the viewpoint of improving flowability during manufacturing, the content of the soft magnetic powder is preferably set to 75 vol% or less. In the shaped body of the composite material, when the filling rate of the soft magnetic powder is adjusted to be low, the relative permeability thereof can be easily reduced. The relative permeability of the shaped body of the composite material is, for example, 5 or more and 50 or less. The relative permeability of the shaped body of the composite material can be further 10 or more and 45 or less, 15 or more and 40 or less, or 20 or more and 35 or less. In this example, the second chip 3B is entirely composed of the shaped body of the composite material.

[0137] The content of the soft magnetic powder in the compression-molded body can be easily increased compared to the shaped body of the composite material. For example, the content of the soft magnetic powder in the compression-molded body is more than 80 vol%, and further 85 vol% or more. The chip composed of the compression-molded body can easily be a chip having a high saturation magnetic flux density and a high relative permeability. The relative permeability of the compression-molded body is, for example, 50 or more and 500 or less. The relative permeability of the compression-molded body can also be 80 or more, 100 or more, 150 or more, or 180 or more. In this example, the first chip 3A including the first recess 4 is entirely composed of the compression-molded body.

[0138] [Dimensions]

[0139] In the case where the reactor 1 of this example is for vehicle use, the length L of the magnetic core 3 in the X direction is, for example, 30 mm or more and 150 mm or less, the width W of the magnetic core 3 in the Y direction is, for example, 30 mm or more and 150 mm or less, and the height H of the magnetic core 3 in the Z direction is, for example, 15 mm or more and 75 mm or less.

[0140] The length TO of the intermediate core 30 in the Y direction is, for example, 10 mm or more and 50 mm or less. The length T1 of the first end core 31 in the X direction and the length T2 of the second end core 32 in the X direction are, for example, 5 mm or more and 40 mm or less. In addition, the length T3 of the first side core 33 in the Y direction and the length T4 of the second side core 34 in the Y direction are, for example, 5 mm or more and 40 mm or less. These lengths are related to the size of the cross-sectional area of the magnetic path of the magnetic core 3.

[0141] [First recess]

[0142] The first end core 31 has the first recess 4 in the first outer surface 310 thereof. The first recess 4 is provided in the middle portion in the Y direction in the first end core 31 when the magnetic core 3 is viewed from the Z direction. The middle portion is a region in the Y direction of the first end core 31 which does not overlap with the both side cores 33, 34. The first recess 4 is preferably symmetrical across the center in the Y direction of the first end core 31. The two closed magnetic paths formed in the magnetic core 3 of the present example are directed toward the direction away from the middle portion in the Y direction. Therefore, the magnetic flux is difficult to pass through in the middle portion in the first outer surface 310. Therefore, even if the first recess 4 is provided at the position of the middle portion in the first outer surface 310, the cross-sectional area of the magnetic path of the first end core 31 is not easily reduced, and the magnetic characteristics of the reactor 1 are not easily lowered.

[0143] The first recess 4 of the present example is a groove shape extending in the Z direction. The first recess 4 of the present example has a length from the upper surface to the lower surface of the first end core 31 in the Z direction. The first recess 4 of such a length has a high effect of reducing the weight of the first end core 31. Unlike the present example, the first recess 4 can also be a length which does not reach the upper surface or the lower surface of the first end core 31.

[0144] The cross-sectional shape of the first recess 4 orthogonal to the extending direction is not particularly limited. In the present example, the cross-sectional shape of the first recess 4 orthogonal to the extending direction is rectangular. The cross-sectional shape refers to the shape surrounded by the bottom surface 40, the two inner wall surfaces 41, 42 opposite in the Y direction, and the opening portion on the outer side in the X direction of the first recess 4. The corners of the rectangle can also have rounded corners. When the cross-sectional shape of the first recess 4 is rectangular, the cross-sectional shape can greatly reduce the volume of the first end core 31 compared to the first recesses of semicircular, triangular, and the like. The first core piece 3A provided with the first recess 4 is a compression-molded body compressed from the X direction. When the cross-sectional shape of the first recess 4 is rectangular, the first core piece 3A is easily demolded from the mold. In addition, a portion of the middle core 30 is provided on the side opposite the first recess 4 in the first core piece 3A, and thus the compressed length of the first core piece 3A in the X direction is not easily different. Therefore, it is easy to produce a dense first core piece 3A. Unlike the present example, the cross-sectional shape of the first recess 4 can also be trapezoidal in which the opening portion is widened. That is, the first recess 4 of which the cross-sectional shape is trapezoidal is a first recess 4 in which the distance between the inner wall surface 41 and the inner wall surface 42 becomes longer as it goes from the bottom surface 40 toward the opening portion. The corners of the trapezoid can also have rounded corners.

[0145] The first recess 4 is preferably within the range of the length TO in the Y direction of the middle core 30 when the magnetic core 3 is viewed from the Z direction. Such a first recess 4 does not easily overlap with the portion in the first end core 31 through which the magnetic flux passes more. Therefore, the cross-sectional area of the magnetic path of the first end core 31 is not easily reduced, and the magnetic characteristics of the reactor 1 are not easily lowered.

[0146] The width Wl of the first recess 4 in the Y direction is preferably 5% or more and 50% or less of the length of the first end core 31 in the Y direction, that is, the width W of the magnetic core 3. More preferably, the width Wl is 10% or more and 35% or less of the width W. In this case, the first recess 4 also does not overlap with the portion in the first end core 31 through which the magnetic flux passes more. Therefore, the cross-sectional area of the magnetic path of the first end core 31 is less likely to decrease, and the magnetic characteristics of the reactor 1 are less likely to decrease. Here, the width Wl of the first recess 4 refers to the width of the opening of the first recess 4.

[0147] The width Wl of the first recess 4 in the Y direction can also be 10% or more and 150% or less of the length T0 of the intermediate core 30 in the Y direction. More preferably, the width Wl is 25% or more and 125% or less of the length T0. In this case, the first recess 4 also does not easily overlap with the portion in the first end core 31 through which the magnetic flux passes more. Therefore, the cross-sectional area of the magnetic path of the first end core 31 is less likely to decrease, and the magnetic characteristics of the reactor 1 are less likely to decrease.

[0148] On the other hand, the depth Dl of the first recess 4 in the X direction is preferably 10% or more and 125% or less of the length Tl of the first end core 31 in the X direction. More preferably, the depth Dl is 20% or more and 100% or less of the length Tl. In this case, the first recess 4 also does not easily overlap with the portion in the first end core 31 through which the magnetic flux passes more. Therefore, the cross-sectional area of the magnetic path of the first end core 31 is less likely to decrease, and the magnetic characteristics of the reactor 1 are less likely to decrease. Here, the depth Dl of the first recess 4 refers to the length from the opening of the first recess 4 to the deepest portion.

[0149]

[0150] Here, the second end core 32 can also have the second recess 5 shown by the two-dot chain line. The second recess 5 has the same structure as the first recess 4. The description of the second recess 5 is obtained by changing "the first recess 4" to "the second recess 5", "the first outer surface 310" to "the second outer surface 320", and "the length Tl" to "the length T2" in the description of the first recess 4.

[0151]

[0152] ​​The reactor 1 can further include at least one of a housing, an adhesive layer, a retaining member, and a molded resin portion. The housing is a member that houses the combination of the coil 2 and the magnetic core 3 inside. The combination housed in the housing can be embedded by a sealing resin portion. The adhesive layer is a layer that fixes the combination to a placement surface, or fixes the combination to an inner bottom surface of the housing, or fixes the housing to the placement surface. The retaining member is a member that is interposed between the coil 2 and the magnetic core 3, and ensures insulation between the coil 2 and the magnetic core 3. The molded resin portion is a structure that covers the outer periphery of the combination, and is interposed between the coil 2 and the magnetic core 3, and integrates the coil 2 and the magnetic core 3.

[0153] <Effects>

[0154] The reactor 1 of the present example having the first recess 4 is lightweight compared to a conventional reactor that does not have the first recess 4.

[0155] In the reactor 1 of the present example, by providing the first recess 4 in the first end core 31, the substantial portion of the first end core 31 is reduced. Therefore, the reactor 1 is lightweight. In addition, because the substantial portion of the first end core 31 is reduced, the productivity of the magnetic core 3, including the cost, that is, the productivity of the reactor 1 is improved. Further, when the second recess 5 is provided in the second end core 32, the weight of the reactor 1 is further reduced.

[0156] The reactor 1 of the present example has magnetic characteristics equivalent to those of a reactor that does not have the first recess 4.

[0157] In the reactor 1 of the present example, the first recess 4 is provided in the Y-direction intermediate portion of the first outer surface 310 of the first end core 31. This intermediate portion is a portion through which magnetic flux is difficult to pass. Therefore, a decrease in the magnetic characteristics of the reactor 1 due to the provision of the first recess 4 in the magnetic core 3 can be suppressed.

[0158] <Embodiment 2>

[0159] Based on Figure 3 The reactor 1 of Embodiment 2 is described. The reactor 1 of Embodiment 2 and the magnetic core 3 of the reactor 1 of Embodiment 1 differ in the division state. The structure of the reactor 1 of the present example, except for the division state of the magnetic core 3, is the same as that of the reactor 1 of Embodiment 1.

[0160] The magnetic core 3 of the reactor 1 of the present example is configured by combining a first chip 3A, a second chip 3B, a third chip 3C, and a fourth chip 3D. The first chip 3A of the present example is configured by a first end core 31 and a portion of the intermediate core 30. The first recess 4 is provided in the first end core 31. The second chip 3B of the present example is configured by a second end core 32 and a portion of the intermediate core 30. The second recess 5 is provided in the second end core 32. The first chip 3A and the second chip 3B are substantially T-shaped when viewed from the Z direction. The first chip 3A and the second chip 3B of the present example are identical in shape and are produced by one mold.

[0161] On the other hand, the third chip 3C of the present example is configured by a first side core 33, and the fourth chip 3D of the present example is configured by a second side core 34. The third chip 3C and the fourth chip 3D are substantially I-shaped when viewed from the Z direction. The third chip 3C and the fourth chip 3D of the present example are identical in shape and are produced by one mold.

[0162] Each of the chips 3A, 3B, 3C, and 3D is a powder-pressed compact or a compact of a composite material. For example, a configuration in which the chips 3A and 3B are powder-pressed compacts and the chips 3C and 3D are compacts of a composite material can be exemplified.

[0163] The reactor 1 of the present example also achieves the same effects as the reactor 1 of Embodiment 1. That is, the reactor 1 of the present example is lightweight and has excellent magnetic characteristics.

[0164] <Embodiment 3>

[0165] Based on Figure 4 The reactor 1 of Embodiment 3 is described. The reactor 1 of Embodiment 3 differs from the reactors 1 of Embodiments 1 and 2 in the division state of the magnetic core 3. The configuration of the reactor 1 of the present example, except for the division state of the magnetic core 3, is the same as that of the reactors 1 of Embodiments 1 and 2.

[0166] The magnetic core 3 of the reactor 1 of the present example is configured by combining a first chip 3A and a second chip 3B. The first chip 3A of the present example is configured by a first end core 31, a second end core 32, a first side core 33, and a second side core 34. The first recess 4 is provided in the first end core 31. The second recess 5 is provided in the second end core 32. The first chip 3A is substantially O-shaped when viewed from the Z direction. On the other hand, the second chip 3B of the present example is configured by the intermediate core 30. The second chip 3B is substantially I-shaped when viewed from the Z direction.

[0167] Each of the chips 3A and 3B is a powder-pressed compact or a compact of a composite material. For example, a configuration in which the first chip 3A is a powder-pressed compact and the second chip 3B is a compact of a composite material can be exemplified.

[0168] The reactor 1 of this example can also achieve the same effects as those of the reactor 1 of Embodiment 1. That is, the reactor 1 of this example is lightweight and has excellent magnetic properties.

[0169] <Implementation Method 4>

[0170] In the fourth embodiment, based on Figure 5 The reactor 1 including the three winding portions 21 , 22 , and 23 will be described.

[0171] The coil 2 of this embodiment includes a first winding portion 21, a second winding portion 22, and a third winding portion 23. The three winding portions 21, 22, and 23 can be configured as follows. Figure 2 The closed magnetic circuit shown can be either a series or independent. An intermediate core 30 is located within the first winding section 21, a first side core 33 is located within the second winding section 22, and a second side core 34 is located within the third winding section 23. The three winding sections 21, 22, and 22 are arranged side by side in the Y direction, with their axes lying on the XY plane.

[0172] The magnetic core 3 of this example is formed by combining a first chip 3A and a second chip 3B. The first chip 3A of this example is composed of a first end core 31, a portion of the middle core 30, a portion of the first side core 33, and a portion of the second side core 34. On the other hand, the second chip 3B of this example is composed of a second end core 32, a portion of the middle core 30, a portion of the first side core 33, and a portion of the second side core 34. The first chip 3A and the second chip 3B viewed from the Z direction are roughly E-shaped. The first chip 3A and the second chip 3B of this example are the same shape and are made using a single mold.

[0173] Each core piece 3A, 3B is a compact of powder or a compact of a composite material. For example, the first core piece 3A is a compact of powder and the second core piece 3B is a compact of a composite material.

[0174] The reactor 1 of this example can also achieve the same effects as those of the reactor 1 of Embodiment 1. That is, the reactor 1 of this example is lightweight and has excellent magnetic properties.

[0175] <Implementation Method 5>

[0176] Converter and Power Conversion Device

[0177] The reactors 1 of Embodiments 1 to 4 are usable for applications satisfying the following energization conditions. As the energization conditions, for example, a maximum direct current of 100 A or more and 1000 A or less, an average voltage of 100 V or more and 1000 V or less, and a use frequency of 5 kHz or more and 100 kHz or less can be listed. The reactors 1 of Embodiments 1 to 4 are representatively usable for a constituent member of a converter placed in a vehicle such as an electric vehicle, a hybrid vehicle, and the like, and a constituent member of a power conversion device provided with the converter.

[0178] A vehicle 1200 such as a hybrid vehicle, an electric vehicle, and the like is provided with a main battery 1210, a power conversion device 1100 connected to the main battery 1210, and a motor 1220 driven by supplied power from the main battery 1210 and used for running. The motor 1220 is representatively a three-phase alternating-current motor, and drives a wheel 1250 at the time of running and functions as a generator at the time of regeneration. In the case of a hybrid vehicle, the vehicle 1200 is provided with an engine 1300 in addition to the motor 1220. The engine 1300 is driven by supplied power from the main battery 1210 or the like. Figure 6 Figure 6 In the example, a socket is shown as a charging site of the vehicle 1200, but a mode provided with a plug can be provided.

[0179] The power conversion device 1100 has a converter 1110 connected to the 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 of the example boosts an input voltage of the main battery 1210 of 200 V or more and 300 V or less to 400 V or more and 700 V or less to supply power to the inverter 1120 at the time of running of the vehicle 1200. The converter 1110 steps down an input voltage output from the motor 1220 via the inverter 1120 at the time of regeneration 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. The inverter 1120 converts the direct current boosted by the converter 1110 to a predetermined alternating current to supply power to the motor 1220 at the time of running of the vehicle 1200, and converts an alternating current output from the motor 1220 to a direct current to output to the converter 1110 at the time of regeneration.

[0180] The converter 1110 is provided with a reactor 1 of Embodiments 1 to 4. Figure 7 ​The device shown includes a plurality of switching elements 1111, a drive circuit 1112 for controlling the operation of the switching elements 1111, and a reactor 1115, which converts the input voltage by repeatedly switching on and off. The so-called input voltage conversion here refers to stepping up and down the voltage. The switching elements 1111 utilize power devices such as field effect transistors and insulated gate bipolar transistors. The reactor 1115 has the following function: utilizing the coil property of hindering the change of the current to flow through the circuit, the change is smoothed when the current is increased or decreased by the switching action. As the reactor 1115, the reactor 1 of any one of the first to fourth embodiments is provided. By providing the reactor 1 that is lightweight and has excellent magnetic properties, the power conversion device 1100 and the converter 1110 are lightweight and have excellent conversion efficiency.

[0181] In addition to converter 1110, vehicle 1200 also includes a power supply device converter 1150 connected to main battery 1210, and an auxiliary power supply converter 1160 connected to auxiliary battery 1230, which serves as a power source for auxiliary devices 1240, and main battery 1210, converting the high voltage of main battery 1210 to a low voltage. Converter 1110 typically performs DC-DC conversion, but power supply device converter 1150 and auxiliary power supply converter 1160 also perform AC-DC conversion. Power supply device converter 1150 may also perform DC-DC conversion. The reactors in power supply device converter 1150 and auxiliary power supply converter 1160 have the same structure as reactor 1 and the like in any of Embodiments 1 to 4, but reactors with appropriately modified sizes, shapes, and the like can be used. Furthermore, converters that convert input power and only perform step-up or step-down can also utilize reactor 1 and the like in any of Embodiments 1 to 4.

[0182] <Experiment>

[0183] Test Example 1

[0184] In Test Example 1, the Figure 2 The effect of the width W1 of the first recess 4 shown here on the inductance and total loss of the reactor 1 was analyzed. Specifically, the reactor 1 of sample number 1, which did not have the first recess 4, and the reactors 1 of samples numbers 2 to 6, which had the first recess 4, were analyzed. The only difference between the reactor 1 of sample number 1 and the reactors 1 of samples numbers 2 to 6 was the presence or absence of the first recess 4. Furthermore, the only difference between the reactors of samples numbers 2 to 6 was the width W1 of the first recess 4. The dimensions of the main parts of the magnetic core 3 of each sample are as follows.

[0185] [Sample No. 1]

[0186] ·The first recessed portion 4...none.

[0187] • Length L of magnetic core 3... 70 mm

[0188] • Width W of magnetic core 3 = width W of first end core 31 and second end core 32... 75 mm

[0189] • Height H of magnetic core 3... 30 mm

[0190] • Length TO in Y direction of intermediate core 30... 30 mm

[0191] • Lengths T1, T2 in X direction of first end core 31 and second end core 32... 12 mm

[0192] • Lengths T3, T4 in Y direction of first side core 33 and second side core 34... 11 mm

[0193] [Sample No. 2]

[0194] • Width W1 of first recess 4... 6 mm

[0195] The width W1 of the first recess 4 is 8% of the width W of the magnetic core 3, and is 20% of the length TO in the Y direction of the intermediate core 30.

[0196] • Depth D1 of first recess 4... 4 mm

[0197] • Length in Z direction of first recess 4... 30 mm

[0198] [Sample No. 3]

[0199] • Width W1 of first recess 4... 12 mm

[0200] The width W1 of the first recess 4 is 16% of the width W of the magnetic core 3, and is 40% of the length TO in the Y direction of the intermediate core 30.

[0201] [Sample No. 4]

[0202] • Width W1 of first recess 4... 18 mm

[0203] The width W1 of the first recess 4 is 24% of the width W of the magnetic core 3, and is 60% of the length TO in the Y direction of the intermediate core 30.

[0204] [Sample No. 5]

[0205] • Width W1 of first recess 4... 24 mm

[0206] The width W1 of the first recess 4 is 32% of the width W of the magnetic core 3, and is 80% of the length TO in the Y direction of the intermediate core 30.

[0207] [Sample No. 6]

[0208] • The width W1 of the first recess 4 is 30 mm

[0209] The width W1 of the first recess 4 is 40% of the width W of the magnetic core 3 and is 100% of the length TO in the Y direction of the middle core 30.

[0210] The simulation experiment of the inductance and the total loss of each sample used JMAG-Designer 18.1 (manufactured by JSOL Corporation) as a commercially available software. In the analysis of the inductance, the inductance (πH) when a current flows through the coil 2 was calculated. The current was changed in the range of 0 A to 300 A. The inductance at the time when the current value was 0 A, 100 A, 200 A, and 300 A is shown in Table 1. The inductance is expressed as a percentage in which the inductance of the sample No. 1 at 0 A is set to 100%.

[0211] In addition, in the analysis of the total loss, the total loss (W) was calculated based on the magnetic flux density distribution and the current density distribution when driven at a direct current of 0 A, an input voltage of 200 V, an output voltage of 400 V, and a frequency of 20 kHz. The total loss of this example includes the iron loss of the magnetic core 3 and the coil loss, and the like. The result is shown in Table 1. The total loss is expressed as a percentage in which the total loss of the sample No. 1 is set to 100%.

[0212] Table 1 shows the volume reduction amount (mm 3 ) of the magnetic core 3 caused by the first recess 4 together.

[0213] [Table 1]

[0214]

[0215] As shown in Table 1, compared with the reactor of the sample No. 1 which is the base model, there is a tendency that the larger the width W1 of the first recess 4, the larger the volume reduction amount of the magnetic core 3, the lower the inductance of the reactor 1, and the higher the total loss. That is, the lightweight of the reactor 1 and the magnetic characteristics of the reactor 1 are in a trade-off relationship. However, by the first recess 4 being located in the middle portion of the first outer surface 310 of the first end core 31, the decrease in the inductance and the increase in the total loss are insignificant. Here, from the viewpoint of maintaining the magnetic characteristics of the reactor 1, the decrease rate of the inductance and the increase rate of the total loss caused by the first recess 4 are preferably 1% or less. From this viewpoint, when it is the sample No. 3 and the sample No. 4, it can be said that the balance between the volume reduction amount and the degree of reduction in the magnetic characteristics is good. That is, the width W1 of the first recess 4 is preferably 12 mm or more and 18 mm or less.

[0216] Further, in order to investigate the relationship between the width W1 of the first recess 4 and the degree of change in the magnetic characteristics of the reactor 1, the deterioration rates of the inductance performance and the deterioration rates of the total loss shown below were investigated. These deterioration rates are unique indices of the present specification.

[0217] [Deterioration rate of inductance performance]

[0218] • (Deterioration rate of inductance performance) = (Decrease amount of inductance) / (Volume reduction amount of magnetic core)

[0219] Here, the decrease amount of inductance in the above formula is the sum of the difference from the inductance of the base model when the current value is 0 A, the difference from the inductance of the base model when the current value is 100 A, the difference from the inductance of the base model when the current value is 200 A, and the difference from the inductance of the base model when the current value is 300 A. For example, the decrease amount of inductance of the sample No. 2 based on the results of Table 1 becomes |100 - 99.97| + |79.43 - 79.40| + |55.71 - 55.67| + |33.42 - 33.40| = 0.12.

[0220] The deterioration rates of inductance of the samples No. 2 to No. 6 are shown in the graph of FIG. 6. The horizontal axis of the graph is the width W1 (mm) of the first recess 4, and the vertical axis is the deterioration rate of inductance performance. In the graph of FIG. 6, the plotted lines of the respective samples are connected with a line. When the slope of the line between the plotted lines shown in FIG. 6 is small, it can be said that the deterioration of inductance performance is small with respect to the increase in the width W1. Figure 8 Figure 8 The deterioration rates of inductance of the samples No. 2 to No. 6 are shown in the graph of FIG. 6. The horizontal axis of the graph is the width W1 (mm) of the first recess 4, and the vertical axis is the deterioration rate of inductance performance. In the graph of FIG. 6, the plotted lines of the respective samples are connected with a line. When the slope of the line between the plotted lines shown in FIG. 6 is small, it can be said that the deterioration of inductance performance is small with respect to the increase in the width W1. Figure 8

[0221] [Deterioration rate of total loss]

[0222] • (Deterioration rate of total loss) = (Increase amount of total loss) / (Volume reduction amount of magnetic core)

[0223] Here, the increase amount of total loss in the above formula is the difference from the total loss of the base model. For example, the increase amount of total loss of the sample No. 2 based on the results of Table 1 is 100.15 - 100.00 = 0.15.

[0224] The deterioration rates of total loss of the samples No. 2 to No. 6 are shown in the graph of FIG. 8. The horizontal axis of the graph is the width W1 (mm) of the first recess 4, and the vertical axis is the deterioration rate of total loss. In the graph of FIG. 8, the plotted lines of the respective samples are connected with a line. When the slope of the line between the plotted lines shown in FIG. 8 is small, it can be said that the deterioration of total loss is small with respect to the increase in the width W1. Figure 9 Figure 9 The deterioration rates of total loss of the samples No. 2 to No. 6 are shown in the graph of FIG. 8. The horizontal axis of the graph is the width W1 (mm) of the first recess 4, and the vertical axis is the deterioration rate of inductance performance. In the graph of FIG. 8, the plotted lines of the respective samples are connected with a line. When the slope of the line between the plotted lines shown in FIG. 8 is small, it can be said that the deterioration of inductance performance is small with respect to the increase in the width W1. Figure 9 As described above, the width W1 of the first recess 4 is preferably 0.5 mm or more and 2.0 mm or less.

[0225] Figure 8 , 9 ​​​​The slope of the line connecting the sample No. 4 having the width W1 of 18 mm and the sample No. 5 having the width W1 of 24 mm is smaller than the slopes of the other lines. Therefore, it can be said that the degree of decrease in the magnetic characteristics of the reactor 1 becomes slightly gentle in the range of the width W1 of 18 mm to 24 mm. Therefore, from the viewpoint of reducing the weight of the magnetic core 3, the width W1 of the first recessed portion 4 can be 18 mm or more and 24 mm or less.

[0226] Test Example 2

[0227] In Test Example 2, the effects of the depth D1 of the first recessed portion 4 on the inductance and the total loss of the reactor 1 were investigated. Figure 2 The depth D1 of the first recessed portion 4 shown in the drawing has an effect on the inductance and the total loss of the reactor 1. Specifically, analysis was performed on the reactor of the sample No. 1 not having the first recessed portion 4 and the reactors 1 of the sample Nos. 7 to 11 having the first recessed portion 4. The reactor of the sample No. 1 is the same as the reactor of the sample No. 1 of Test Example 1. The only difference between the reactors 1 of the sample Nos. 7 to 11 is the depth D1 of the first recessed portion 4. The dimensions of the main part of the magnetic core 3 of each sample are as follows.

[0228] [Sample No. 7]

[0229] • Depth D1 of first recessed portion 4... 2 mm

[0230] The depth D1 of the first recessed portion 4 is 16% of the length T1 in the X direction of the first end core 31.

[0231] • Width W1 of first recessed portion 4... 12 mm

[0232] • Length in Z direction of first recessed portion 4... 30 mm

[0233] [Sample No. 8]

[0234] • Depth D1 of first recessed portion 4... 4 mm

[0235] The depth D1 of the first recessed portion 4 is 33% of the length T1 in the X direction of the first end core 31.

[0236] [Sample No. 9]

[0237] • Depth D1 of first recessed portion 4... 6 mm

[0238] The depth D1 of the first recessed portion 4 is 50% of the length T1 in the X direction of the first end core 31.

[0239] [Sample No. 10]

[0240] • Depth D1 of first recessed portion 4... 8 mm

[0241] The depth D1 of the first recess 4 is 66% of the length T1 of the first end core 31 in the X direction.

[0242] [Sample No. 11]

[0243] Depth D1 of the first recess 4: 10 mm

[0244] The depth D1 of the first recess 4 is 83% of the length T1 of the first end core 31 in the X direction.

[0245] The inductance and total loss of each sample were determined by the same method as in Test Example 1. The results are shown in Table 2.

[0246] [Table 2]

[0247]

[0248] As shown in Table 2, compared to the reactor of Sample No. 1, the base model, the greater the depth D1 of the first recess 4, that is, the greater the volume reduction of the magnetic core 3, the lower the inductance of the reactor 1 and the higher the total loss. However, since the first recess 4 is located in the center of the first outer surface 310 of the first end core 31, the reduction in inductance and the increase in total loss are negligible. However, from the perspective of maintaining the magnetic properties of the reactor 1, the reduction in inductance and the increase in total loss due to the provision of the first recess 4 are preferably kept below 1%. From this perspective, Samples No. 8 and No. 9 can be said to have a good balance between volume reduction and improvement in magnetic properties. In other words, the depth D1 of the first recess 4 is preferably between 4 mm and 6 mm.

[0249] Furthermore, in order to investigate the relationship between the depth D1 of the first recess 4 and the degree of change in the magnetic characteristics of the reactor 1, the degradation rate of the inductance and the degradation rate of the total loss of each sample were investigated. The definitions of the two degradation rates are the same as those of the two degradation rates in Test Example 1. The results are presented in Figure 10 、 11 Shown in.

[0250] Figure 10 This is a graph showing the degradation rates of the inductance of Samples No. 7 to No. 11. Figure 10 The horizontal axis of the graph represents the depth D1 (mm) of the first recess 4 , and the vertical axis represents the inductance degradation rate. Figure 11 Graph showing the degradation rate of the total loss of samples No. 7 to No. 11. The horizontal axis of the graph is the depth D1 (mm) of the first recess 4, and the vertical axis is the degradation rate of the total loss. Figure 10 、 11 In the graph, the plots of the individual samples are connected by lines.

[0251] when Figure 10 、11 The slope of the line connecting the plots shown is small, and it can be said that the degree of degradation of the inductance and the total loss is small with respect to the increase in the depth D1. As shown in Figure 10 Figure 10 、 11 The slope of the line connecting the plots shown is small, and it can be said that the degree of degradation of the inductance and the total loss is small with respect to the increase in the depth D1. As shown in

[0252] Test Example 3

[0253] In Test Example 3, whether the rate of decrease in the magnetic characteristics caused by the provision of the first recess 4 differs depending on whether the magnetic core 3 is a powder compact or a composite material was investigated. The information on each test sample is as follows. The dimensions L, W, H, T0, T1, T2, T3, T4 of the magnetic core 3 of each test sample were the same as those of Test Example 1, Test Sample No. 1.

[0254] [Test Sample No. 20]

[0255] • The entire magnetic core 3 was a powder compact.

[0256] • It did not have the first recess 4.

[0257] [Test Sample No. 21]

[0258] • The entire magnetic core 3 was a powder compact.

[0259] • It had the first recess 4.

[0260] • The width W1 of the first recess 4 was... 12 mm

[0261] • The depth D1 of the first recess 4 was... 4 mm

[0262] [Test Sample No. 22]

[0263] • The entire magnetic core 3 was a composite material.

[0264] • It did not have the first recess 4.

[0265] [Test Sample No. 23]

[0266] • The entire magnetic core 3 was a composite material.

[0267] • It had the first recess 4.

[0268] • The width W1 of the first recess 4 was... 12 mm

[0269] • The depth D1 of the first recess 4 was... 4 mm

[0270] The inductance and total loss of sample No. 20 to sample No. 23 were measured. The measurement method was the same as that of Test Example 1. The measurement results are shown in Table 3. The inductance of Table 3 is expressed in percentage with the inductance of sample No. 20 at 0 A being set to 100%. In addition, the total loss of Table 3 is expressed in percentage with the total loss of sample No. 20 being set to 100%. In the parentheses shown in each column of sample No. 21 and sample No. 23 in Table 3, the deterioration rate with respect to sample No. 20 and sample No. 22 is expressed in percentage. When the deterioration rate of inductance is negative, it can be considered that the magnetic characteristics of the reactor 1 are reduced. In addition, when the change rate of total loss is positive, it can be considered that the magnetic characteristics of the reactor 1 are reduced.

[0271] [Table 3]

[0272]

[0273] As shown in Table 3, the deterioration rate of sample No. 21 in which the magnetic core 3 is composed of a press powder molded body is smaller than the deterioration rate of sample No. 23 in which the magnetic core 3 is composed of a composite material. Therefore, in the case where the first recess 4 is provided to the first end core 31, it is preferable that the first end core 31 is a press powder molded body.

[0274] BRIEF DESCRIPTION OF DRAWINGS

[0275] 1 REACTOR

[0276] 2 COIL

[0277] 21 first winding portion, 22 second winding portion, 23 third winding portion, 2A,

[0278] 2B end portion

[0279] 211 first end surface, 212 second end surface

[0280] 213 first side surface, 214 second side surface

[0281] 3 MAGNETIC CORE

[0282] 3g gap portion

[0283] 3A first chip, 3B second chip, 3C third chip, 3D fourth chip

[0284] 30 intermediate core, 31 first end core, 32 second end core

[0285] 33 first side core, 34 second side core

[0286] 310 first outer surface, 320 second outer surface

[0287] 4 FIRST RECESS

[0288] 40 bottom surface, 41, 42 inner wall surface

[0289] 5 second recess

[0290] 1100 power conversion device

[0291] 1110 converter, 1111 switching element, 1112 drive circuit

[0292] 1115 reactor, 1120 inverter

[0293] 1150 converter for power supply device, 1160 converter for auxiliary machine power supply

[0294] 1200 vehicle

[0295] 1210 main battery, 1220 motor, 1230 auxiliary battery

[0296] 1240 auxiliary machine, 1250 wheel

[0297] 1300 engine

[0298] D1 depth

[0299] H height

[0300] L, T0, T1, T2, T3, T4 length

[0301] W, W1 width

Claims

1. A reactor comprising a coil and a magnetic core, The coil has a first winding portion, The magnetic core has: an intermediate core disposed inside the first winding portion; a first end core facing a first end surface of the first winding portion; a second end core facing a second end surface of the first winding portion; a first side core, disposed outside the first side surface of the first winding portion, connecting the first end core and the second end core; and The second side core is arranged outside the second side surface of the first winding portion and connects the first end core and the second end core. The first end core comprises: a first outer surface located away from the first end surface in the X direction; and a first recessed portion, provided on the first outer surface; The cross-sectional shape of the first recessed portion perpendicular to the Z direction is a rectangle. When the magnetic core is viewed from the Z direction, the first recess is provided at a middle portion of the first end core in the Y direction. When the magnetic core is viewed from the Z direction, the width of the first recess in the Y direction is greater than or equal to 40% and less than or equal to 80% of the length of the intermediate core in the Y direction, and the depth of the first recess in the X direction is greater than or equal to 50% and less than or equal to 66% of the length of the first end core in the X direction. The X direction is a direction along the axis direction of the intermediate core, The Y direction is the direction in which the middle core, the first side core, and the second side core are arranged in parallel. The Z direction is a direction perpendicular to the X direction and the Y direction.

2. The reactor according to claim 1, wherein: When the magnetic core is viewed in plan from the Z direction, the first recessed portion is located within a range of a length of the intermediate core in the Y direction.

3. The reactor according to claim 1 or claim 2, wherein: The first recess is in a groove shape extending along the Z direction.

4. The reactor according to claim 1 or claim 2, wherein: The magnetic core has a plurality of chips. One of the plurality of chips is a first chip including at least the first end core, The first core sheet is a compact of raw material powder containing soft magnetic powder.

5. The reactor according to claim 1 or claim 2, wherein: When looking down at the magnetic core from the Z direction, The width of the first recess in the Y direction is not less than 5% and not more than 50% of the length of the first end core in the Y direction.

6. The reactor according to claim 1 or claim 2, wherein: The second end core comprises: a second outer surface located away from the second end surface in the X direction; and A second recess is provided on the second outer surface. When the magnetic core is viewed from the Z direction, the second recessed portion is provided at a middle portion of the second end core in the Y direction.

7. The reactor according to claim 1 or claim 2, wherein: The coil further includes a second winding portion and a third winding portion, The first side core is arranged inside the second winding portion, The second side core is arranged inside the third winding portion. 8 . A converter comprising the reactor according to claim 1 . 9 . A power conversion device comprising the converter according to claim 8 .

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