Reactor, converter, and power conversion device

Abstract

This reactor includes a coil and a magnetic core, wherein: the magnetic core includes a first core and a second core that are combined in an X direction to form a θ shape; the first core includes a first end core part, at least a portion of a middle core part, and at least a portion of both side core parts including a first side core part and a second side core part; the second core includes a second end core part, a remainder of the middle core part, and a remainder of each of the first side core part and the second side core part; each of the first side core part and the second side core part of the first core has a tip surface; the surface of the second core has a facing surface facing the tip surface; the tip surface has a first chamfered portion; the first chamfered portion includes at least a first outer chamfered portion among the first outer chamfered portion and a first inner chamfered portion; and the chamfer width of the first outer chamfered portion is greater than the chamfer width of the first inner chamfered portion.

Description

Technical Field

[0001] The present disclosure relates to a reactor, a converter, and a power conversion device. This application claims priority based on Japanese Patent Application No. 2020-141156 filed on August 24, 2020, and incorporates all the descriptions described in the Japanese application.

Background Art

[0002] A reactor is included in a component of a converter mounted on a vehicle such as a hybrid vehicle. The reactor includes a coil and a magnetic core. FIGS. 5 to 8 of Patent Document 1 describe a reactor including one coil and a magnetic core formed by combining two E-shaped core pieces. This magnetic core is a so-called E-E type core. This magnetic core is configured in a θ shape by combining the end faces of both core pieces to face each other. The magnetic core has an end core portion, a middle core portion, and a side core portion. The end core portion is disposed on the end face side of the coil so as to sandwich the coil in the axial direction. The middle core portion is disposed inside the coil. The side core portion is disposed outside the coil so as to sandwich the middle core portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The reactor of the present disclosure is a reactor including a coil and a magnetic core, wherein the magnetic core includes a first core and a second core configured in a θ shape by being combined in the X direction, the first core includes a first end core portion, at least a part of the middle core portion, and at least a part of both side core portions including a first side core portion and a second side core portion, The second core includes a second end core portion, the remaining portion of the middle core portion, and the remaining portions of each of the first side core portion and the second side core portion. The first end core portion faces the first end surface of the coil. The second end core portion faces the second end surface of the coil. The middle core portion is disposed inside the coil. The first side core portion and the second side core portion are disposed outside the coil so as to sandwich the middle core portion. Each of the first side core portion and the second side core portion of the first core has a tip surface facing the second core. The surface of the second core has an opposing surface facing the tip surface. When the magnetic core is viewed from the Z direction, the outer edge of the opposing surface is located inside in the Y direction from the outer edge of the tip surface, or is aligned with the outer edge of the tip surface in the Y direction, and the inner edge of the opposing surface and the inner edge of the tip surface are substantially aligned in the Y direction. The tip surface has a first chamfered portion along the Z direction. The first chamfered portion includes at least the first outer chamfered portion connected to the outer edge of the tip surface and the first inner chamfered portion connected to the inner edge of the tip surface. The chamfer width of the first outer chamfered portion is larger than the chamfer width of the first inner chamfered portion. The X direction is a direction along the axial direction of the middle core portion. The Y direction is a direction in which the middle core portion, the first side core portion, and the second side core portion are arranged in parallel. The Z direction is a direction perpendicular to both the X direction and the Y direction.

[0005] The converter of the present disclosure includes the reactor of the present disclosure.

[0006] The power conversion device of the present disclosure includes the converter of the present disclosure.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

[0008] [Problems to be Solved by the Present Disclosure] Reduction of losses in a reactor is required.

[0009] Therefore, one of the objects of the present disclosure is to provide a reactor capable of reducing losses. Another object of the present disclosure is to provide a converter including the above reactor. Still another object of the present disclosure is to provide a power conversion device including the above converter.

[0010] [Effects of the Present Disclosure] The reactor of the present disclosure can reduce losses. Further, the converter and the power conversion device of the present disclosure are excellent in efficiency.

[0011] [Description of Embodiments of the Present Disclosure] In a magnetic core having an E-shaped core piece, the E-shaped core piece includes at least a part of both side core portions. Each side core portion of the E-shaped core piece has a front end face facing the other core piece. The other core piece has a facing face facing the front end face. The front end face is in contact with a part of the facing face. Generally, a chamfered portion is provided on the front end face of each side core portion. The chamfered portion is formed on the front end face for reasons such as the molding of the core piece. Usually, the chamfered portion is symmetrically formed on both sides of the outer edge and the inner edge of the front end face. The outer edge of the front end face is the edge on the side far from the middle core portion among the edges constituting the front end face. The inner edge of the front end face is the edge on the side close to the middle core portion among the edges constituting the front end face.

[0012] If chamfered portions are symmetrically provided on both sides of the outer edge and the inner edge on the front end face of the side core portion, it may affect the flow of magnetic flux. In particular, if a large chamfered portion is formed on the inner edge of the front end face, the flow of magnetic flux is inhibited between the front end face and the facing face. Therefore, in a conventional reactor, since the flow of magnetic flux is inhibited in the magnetic core, losses are likely to occur.

[0013] The reactor of the present disclosure is made based on the above problems. First, embodiments of the present disclosure will be listed and described.

[0014] (1) The reactor according to an embodiment of the present disclosure is a reactor including a coil and a magnetic core, wherein the magnetic core includes a first core and a second core configured in a θ shape by being combined in the X direction, the first core includes a first end core portion, at least a part of a middle core portion, and at least a part of both side core portions including a first side core portion and a second side core portion, the second core includes a second end core portion, the remainder of the middle core portion, and the remainder of each of the first side core portion and the second side core portion, the first end core portion faces a first end face of the coil, The second end core portion faces the second end surface of the coil. The middle core portion is disposed inside the coil. The first side core portion and the second side core portion are disposed outside the coil so as to sandwich the middle core portion. Each of the first side core portion and the second side core portion of the first core has a tip surface facing the second core. The surface of the second core has an opposing surface facing the tip surface. When the magnetic core is viewed from the Z direction, The outer edge of the opposing surface is located inside in the Y direction from the outer edge of the tip surface, or is aligned with the outer edge of the tip surface in the Y direction, and The inner edge of the opposing surface and the inner edge of the tip surface are substantially aligned in the Y direction. The tip surface has a first chamfered portion along the Z direction. The first chamfered portion includes at least the first outer chamfered portion connected to the outer edge of the tip surface and the first inner chamfered portion connected to the inner edge of the tip surface. The chamfer width of the first outer chamfered portion is larger than the chamfer width of the first inner chamfered portion. The X direction is a direction along the axial direction of the middle core portion. The Y direction is a direction in which the middle core portion, the first side core portion, and the second side core portion are arranged in parallel. The Z direction is a direction orthogonal to both the X direction and the Y direction.

[0015] The above reactor can reduce losses. The reason is that the flow of magnetic flux is less likely to be inhibited compared to a comparison core. The comparison core refers to a core having the same specifications as the first core of the above reactor except that the tip surface has a first outer chamfered portion and a first inner chamfered portion, and the chamfer width of the first outer chamfered portion is the same as the chamfer width of the first inner chamfered portion. In the above reactor, "the outer edge of the opposing surface is located inside the outer edge of the front end surface in the Y direction" means that the outer edge of the opposing surface is displaced inward in the Y direction from the outer edge of the front end surface. Further, "the outer edge of the opposing surface is aligned with the outer edge of the front end surface in the Y direction" means that the outer edge of the opposing surface and the outer edge of the front end surface are not displaced in the Y direction.

[0016] The front end surface is the end surface in the X direction of the first side core portion and the second side core portion of the first core. The opposing surface is the surface of the second core that faces the front end surface of the first core. The front end surface of the first core is in contact with a part of the opposing surface of the second core. When magnetic flux flows through the magnetic core, in each side core portion, the magnetic flux becomes dense in the inner region in the Y direction and becomes sparser in the outer region in the Y direction. When magnetic flux passes between the front end surface of the first core and the opposing surface of the second core, if an outer chamfered portion is formed on the front end surface, the magnetic flux flowing outside the side core portion will detour around the outer chamfered portion. However, since the magnetic flux flowing outside is small in the first place, the magnetic flux itself that detours around the outer chamfered portion is small. Therefore, even if the chamfer width of the outer chamfered portion is large, there is almost no influence on the magnetic flux flowing through the first core and the second core. Also, if an inner chamfered portion is formed on the front end surface, the magnetic flux flowing inside the side core portion will detour around the inner chamfered portion. In the above reactor, the chamfer width of the first inner chamfered portion is smaller than the chamfer width of the first outer chamfered portion. Therefore, the magnetic flux that detours around the inner chamfered portion is small. Thus, the magnetic flux flowing inside flows relatively smoothly between the first core and the second core. Therefore, since the flow of magnetic flux between the first core and the second core is hardly inhibited, losses can be reduced.

[0017] On the other hand, in the above comparison core, the chamfer width of the first inner chamfered portion is the same as the chamfer width of the first outer chamfered portion, and the chamfer width of the first inner chamfered portion is relatively large. Therefore, the magnetic flux flowing inside the side core portion will detour around the inner chamfered portion significantly. Therefore, since the flow of magnetic flux between the first core and the second core is inhibited, losses occur.

[0018] In addition, the above reactor can be expected to reduce the weight of the magnetic core. This is because the larger the chamfer width of the first outer chamfered portion, the smaller the volume of the first core. Therefore, since the weight of the first core is reduced, the weight of the magnetic core can be reduced. Thus, the weight of the reactor can be reduced.

[0019] (2) As one form of the above reactor, The chamfer width of the first outer chamfered portion may be 10% or more and 45% or less of the width in the Y direction at the tip surface.

[0020] In the above form, since the chamfer width of the first outer chamfered portion is 10% or more of the width of the tip surface, it is easy to reduce the weight of the magnetic core. Also, in the above form, it is easy to reduce losses. This is because when the chamfer width of the first outer chamfered portion is 45% or less of the width of the tip surface, it is easy to secure the contact area between the tip surface and the opposing surface. By securing the contact area between the tip surface and the opposing surface, magnetic flux easily flows between the first core and the second core. Therefore, it is easy to reduce losses.

[0021] (3) As one form of the above reactor, The chamfer width of the first inner chamfered portion may be 12.5% or less of the width in the Y direction at the tip surface.

[0022] In the above form, it is easy to effectively reduce losses. When the chamfer width of the first inner chamfered portion is 12.5% or less of the width of the tip surface, it is easy to suppress the magnetic flux from taking a roundabout path due to the first inner chamfered portion. Therefore, it is easy to suppress the occurrence of losses caused by the flow of magnetic flux between the first core and the second core being inhibited. Furthermore, if the chamfer width of the first inner chamfered portion is 12.5% or less of the width of the tip surface, it is easy to secure the contact area between the tip surface and the opposing surface. By securing the contact area between the tip surface and the opposing surface, magnetic flux easily flows between the first core and the second core. Therefore, losses can be effectively reduced.

[0023] (4) As one form of the above reactor, The chamfer width of the first inner chamfered portion may be 2 mm or less.

[0024] The above-described embodiment is likely to effectively reduce losses. By setting the chamfer width of the first inner chamfer portion to 2 mm or less, it is easy to suppress the magnetic flux from taking a roundabout path due to the first inner chamfer portion. Therefore, it is easy to suppress the generation of losses caused by the flow of magnetic flux being inhibited between the first core and the second core.

[0025] (5) As one form of the above reactor, The first outer chamfer portion may be a round chamfer.

[0026] The above-described embodiment is likely to suppress the loss of the outer edge of the tip surface. If it is a round chamfer, there are no corners, so it is difficult to chip.

[0027] (6) As one form of the above reactor, The first core is a molded body of a composite material in which soft magnetic powder is dispersed in resin, The second core may be a compacted molded body of raw material powder containing soft magnetic powder.

[0028] The above-described embodiment is likely to obtain a predetermined inductance. This is because by providing a magnetic core with a molded body of a composite material having a lower relative permeability than the compacted molded body, the magnetic characteristics of the entire magnetic core can be adjusted. Furthermore, in the above-described embodiment, even if there is no gap portion in the magnetic core, the magnetic characteristics of the entire magnetic core can be adjusted. Since it is not necessary to provide a gap portion in the magnetic core, leakage magnetic flux from the gap portion can be suppressed. Therefore, losses caused by leakage magnetic flux can be reduced.

[0029] (7) As one form of the above reactor, The relative permeability of the first core may be 5 or more and 50 or less.

[0030] The above-described embodiment is likely to obtain a predetermined inductance.

[0031] (8) As one form of the above reactor, The relative permeability of the second core may be 50 or more and 500 or less.

[0032] The above-described form makes it easy to obtain a predetermined inductance.

[0033] (9) As one form of the above reactor, it can be mentioned that the relative permeability of the second core is higher than that of the first core.

[0034] The above-described form makes it easy to obtain a predetermined inductance. The magnetic characteristics of the first core and the second core are different. Specifically, since the relative permeability of the second core is higher than that of the first core, the magnetic characteristics of the entire magnetic core can be adjusted. Furthermore, in the above-described form, even if there is no gap portion in the magnetic core, the magnetic characteristics of the entire magnetic core can be adjusted. Since it is not necessary to provide a gap portion in the magnetic core, leakage magnetic flux from the gap portion can be suppressed. Therefore, losses caused by leakage magnetic flux can be reduced.

[0035] Furthermore, in the above-described embodiment, while maintaining the electromagnetic performance, it is possible to make the width of the opposing surface of the second core shorter than the width of the front end surface of the first core. By making the width of the opposing surface of the second core shorter than the width of the front end surface of the first core, weight reduction can be achieved as will be described later. The reason why the electromagnetic performance can be maintained even when the width of the opposing surface of the second core is shorter than the width of the front end surface of the first core is that the relative permeability of the second core is higher than the relative permeability of the first core. When the width of the opposing surface of the second core is shorter than the width of the front end surface of the first core, the magnetic path area of the magnetic core becomes locally smaller at the contact location between the front end surface and the opposing surface. By the relationship between the relative permeabilities of the second core and the first core satisfying the above relationship, it is easy to balance the magnetic flux that can pass between the front end surface and the opposing surface. In other words, the balance of the magnetic flux can be generally maintained between the first core and the second core. If the first core and the second core have the same relative permeability, but the area of the opposing surface is smaller than the front end surface, then in the vicinity of the contact location between the front end surface and the opposing surface, the magnetic flux flowing through the second core becomes smaller than the magnetic flux flowing through the first core. Although the area of the opposing surface is smaller than the front end surface, if the relative permeabilities of the first core and the second core are different, and within the range where the above magnetic fluxes are generally balanced, the influence on the magnetic fluxes flowing through the first core and the second core becomes negligible. Therefore, due to the high relative permeability of the second core, it is possible to maintain electromagnetic performance such as inductance even when the width of the opposing surface of the second core is short. The width of the front end surface or the opposing surface is the length along the respective Y direction, and is equal to the distance in the Y direction between the outer edge and the inner edge on the front end surface or the opposing surface.

[0036] (10) As one form of the above reactor, The outer edge of the opposing surface is located inward in the Y direction from the outer edge of the front end surface, It can be mentioned that the width in the Y direction of the opposing surface is shorter than the width in the Y direction of the front end surface.

[0037] The above-described form can achieve weight reduction. The reason is that the volume of the second core can be reduced. In the above-described form, the outer edge of the opposing surface of the second core is located inside in the Y direction from the outer edge of the front end surface of the first core, and the width of the opposing surface is shorter than the width of the front end surface. If the front end surface and the opposing surface satisfy such a positional relationship, the outer width of the second core becomes narrower than the outer width of the first core, so that the volume of the second core can be reduced. Therefore, since the weight of the second core is reduced, the weight of the magnetic core can be reduced. The outer width of the first core or the outer width of the second core is respectively the maximum length along the Y direction of the first core or the second core. The outer width of the first core or the outer width of the second core typically corresponds to the width of each of the first end core portion or the second end core portion, that is, the length along the Y direction.

[0038] (11) As one form of the reactor described in the above (10), The width in the Y direction on the opposing surface may be 60% or more and 92% or less of the width in the Y direction on the front end surface.

[0039] The above-described form can easily achieve weight reduction while maintaining electromagnetic performance. The reason for maintaining electromagnetic performance is that since the width of the opposing surface is 60% or more of the width of the front end surface, it is easy to ensure the contact area between the front end surface and the opposing surface. By ensuring the contact area between the front end surface and the opposing surface, it is easy to balance the magnetic flux between the front end surface and the opposing surface. That is, since the balance of the magnetic flux can be generally maintained between the first core and the second core, it is easy to maintain electromagnetic performance such as inductance. The reason for weight reduction is that since the width of the opposing surface is 92% or less of the width of the front end surface, the width of the opposing surface becomes sufficiently short. Since the width of the opposing surface is sufficiently short, the weight of the second core can be effectively reduced.

[0040] (12) As one form of the reactor, The opposing surface has a second chamfered portion along the Z direction, The second chamfered portion includes at least the second outer chamfered portion connected to the outer edge of the opposing surface and the second inner chamfered portion connected to the inner edge of the opposing surface. The chamfer width of the second outer chamfer portion may be larger than the chamfer width of the second inner chamfer portion.

[0041] The above form is easy to suppress the occurrence of losses. This is because the flow of magnetic flux is hardly inhibited between the first core and the second core. The above form can further expect weight reduction of the magnetic core. This is because the volume of the second core becomes smaller due to the opposing surface having the second chamfer portion. Therefore, since the weight of the second core is reduced, the weight of the magnetic core can be reduced. Thus, the weight of the reactor can be reduced.

[0042] (13) As one form of the above reactor, The first core includes all of each of the first side core portions and the second side core portions, The opposing surface may be provided in the second end core portion of the second core.

[0043] Typically, the above form can obtain E-T type and E-I type magnetic cores.

[0044] (14) As one form of the above reactor, The first core includes a part of each of the first side core portions and the second side core portions, The opposing surface may be provided in the remaining portions of each of the first side core portion and the second side core portion of the second core.

[0045] Typically, the above form can obtain E-E type and E-U type magnetic cores.

[0046] (15) The converter according to the embodiment of the present disclosure, includes the reactor according to any one of (1) to (14) above.

[0047] Since the above converter includes the above reactor, it is excellent in efficiency. This is because the efficiency of the converter is improved by reducing the loss of the reactor.

[0048] (16) The power conversion device according to an embodiment of the present disclosure is equipped with the converter described in (15) above.

[0049] Since the power conversion device is equipped with the converter, it is excellent in efficiency. This is because the efficiency of the power conversion device is improved by reducing the loss of the reactor in the converter.

[0050] [Details of Embodiments of the Present Disclosure] Specific examples of 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. Note that the present invention is not limited to these examples, and is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0051] [Embodiment 1] [Reactor] With reference to FIGS. 1 to 4, the reactor 1 of Embodiment 1 will be described. As shown in FIGS. 1 and 2, the reactor 1 includes a coil 2 and a magnetic core 3. The magnetic core 3 includes a first core 3a and a second core 3b. As shown in FIG. 3, the magnetic core 3 is configured in a θ shape as a whole by combining the first core 3a and the second core 3b. The first core 3a has a tip surface 3af described later. The second core 3b has a facing surface 3bf facing the tip surface 3af.

[0052] One of the features of the reactor 1 of the present embodiment is that it satisfies the following requirements (a) to (d). (a) The tip surface 3af of the first core 3a and the facing surface 3bf of the second core 3b have a specific positional relationship. (b) The tip surface 3af has a first chamfered portion 41. (c) The first chamfered portion 41 includes at least a first outer chamfered portion 41o. (d) The chamfer width of the first outer chamfered portion 41o is larger than the chamfer width of the first inner chamfered portion 41i.

[0053] The configuration of the reactor 1 will be described in detail below. For convenience of explanation, the coil 2 is shown by a two-dot chain line in FIG. 3. This also applies to FIGS. 9, 10, and 16, which are respectively referred to in Embodiments 2 to 4 described later.

[0054] (Coil) As shown in FIGS. 1 and 2, the coil 2 has one winding portion 21. The winding portion 21 is formed by winding a winding wire in a spiral shape. As the winding wire, a known winding wire can be used. In the present embodiment, the winding wire is a covered flat wire. The conductor of the winding wire is composed of a flat copper wire. The insulating coating of the covered flat wire is made of enamel. The coil 2 is an edgewise coil in which the covered flat wire is edgewise wound.

[0055] The shape of the winding portion 21 in the present embodiment is a rectangular cylindrical shape. The rectangle includes a square. That is, the end face shape of the winding portion 21 is a rectangular frame shape. The shape of the winding portion 21 may be a cylindrical shape. By the shape of the winding portion 21 being a rectangular cylindrical shape, it is easy to increase the contact area between the winding portion 21 and the installation object as compared with the case where the winding portion 21 has a cylindrical shape with the same inner area. The inner area refers to the opening area of the space surrounded by the inner circumference of the winding portion 21. Since the contact area becomes large, it is easy to dissipate heat to the installation object through the winding portion 21. Moreover, it is easy to stably install the winding portion 21 on the installation object. The corners of the winding portion 21 are rounded.

[0056] The end portions 21a and 21b of the winding portion 21 are respectively drawn out to the outer peripheral side of the winding portion 21 at one end side and the other end side in the axial direction of the winding portion 21. The insulating coatings of the end portions 21a and 21b of the winding portion 21 are peeled off and the conductors are exposed. Terminal members (not shown) are attached to the end portions 21a and 21b. An external device is connected to the coil 2 via this terminal member. The illustration of the external device is omitted. Examples of the external device include a power source that supplies power to the coil 2.

[0057] (Magnetic Core) As shown in FIG. 3, the magnetic core 3 includes a middle core portion 30, a first end core portion 31, a second end core portion 32, a first side core portion 33, and a second side core portion 34. In FIG. 3, the boundaries of the respective core portions are indicated by two-dot chain lines. This also applies to FIGS. 9, 10, and 16, which will be referred to in Embodiments 2 to 4 described later. In the present embodiment, the X direction, Y direction, and Z direction are defined as follows. The X direction is the direction along the axial direction of the middle core portion 30. The Y direction is the direction orthogonal to the X direction and is the direction in which the middle core portion 30, the first side core portion 33, and the second side core portion 34 are arranged in parallel. The Z direction is the direction orthogonal to both the X direction and the Y direction. The X direction corresponds to the length direction. The Y direction corresponds to the width direction. The Z direction corresponds to the height direction.

[0058] As shown in FIG. 3, when viewed from the Z direction, the shape of the magnetic core 3 is θ-shaped. When the coil 2 is energized, magnetic flux flows through the magnetic core 3 and a θ-shaped closed magnetic circuit is formed. In FIG. 3, the thick dashed arrows indicate the flow of magnetic flux. The direction of the magnetic flux flow may be opposite to the direction of the arrows shown in FIG. 3. The magnetic flux generated by the coil 2 passes from the middle core portion 30 through the first end core portion 31, the first side core portion 33, the second side core portion 34, and the second end core portion 32 and returns to the middle core portion 30. That is, in the magnetic core 3, two annular closed magnetic circuits passing through the first side core portion 33 and the second side core portion 34 are formed respectively.

[0059] 〈Middle Core Portion〉 The middle core portion 30 is the portion of the magnetic core 3 that is disposed inside the coil 2. In the present embodiment, both ends of the middle core portion 30 along the X direction protrude from both end faces 2a and 2b of the coil 2. This protruding portion is also a part of the middle core portion 30.

[0060] The shape of the middle core portion 30 is not particularly limited as long as it corresponds to the inner shape of the winding portion 21. As shown in FIG. 2, the shape of the middle core portion 30 of the present embodiment is substantially rectangular parallelepiped. When viewed from the X direction, the corners of the middle core portion 30 may be rounded along the inner peripheral surface of the corners of the winding portion 21. That is, the corners of the outer peripheral surface of the middle core portion 30 may be rounded.

[0061] The middle core portion 30 may or may not be divided in the X direction. The middle core portion 30 of the present embodiment is divided into two in the X direction and has a first middle core portion 30a and a second middle core portion 30b. The first middle core portion 30a is located on one side of the middle core portion 30 in the X direction, specifically, on the side of the first end core portion 31. The second middle core portion 30b is located on the other side of the middle core portion 30 in the X direction, specifically, on the side of the second end core portion 32. In the present embodiment, the first middle core portion 30a and the second middle core portion 30b are in contact with each other, and there is substantially no gap between the first middle core portion 30a and the second middle core portion 30b. That is, the middle core portion 30 does not have a gap portion between the first middle core portion 30a and the second middle core portion 30b. The length of each of the first middle core portion 30a and the second middle core portion 30b may be appropriately set so as to obtain predetermined magnetic characteristics. The length referred to here means the length in the X direction. The first middle core portion 30a may be longer or shorter than the second middle core portion 30b. In the present embodiment, the first middle core portion 30a is longer than the second middle core portion 30b. The widths of the first middle core portion 30a and the second middle core portion 30b are equal. The width referred to here means the width in the Y direction.

[0062] The middle core portion 30 may have a gap portion. The gap portion may be provided between the first middle core portion 30a and the second middle core portion 30b. The position of the gap portion is preferably inside the winding portion 21. Since the gap portion is located inside the winding portion 21, the gap PartIt is easy to suppress the leakage magnetic flux from . Therefore, it is easy to reduce the loss caused by the leakage magnetic flux. The length of the gap portion may be appropriately set so as to obtain predetermined magnetic characteristics. Examples of the length of the gap portion include 0.1 mm or more, and further 0.3 mm or more. Examples of the upper limit of the length of the gap portion include 2 mm or less, further 1.5 mm or less, and 1.0 mm or less. The gap portion may be an air gap, or a non-magnetic material such as resin or ceramics may be disposed.

[0063] 〈First End Core Portion · Second End Core Portion〉 The first end core portion 31 is a portion of the magnetic core 3 that faces the first end face 2a of the coil 2. The second end core portion 32 is a portion of the magnetic core 3 that faces the second end face 2b of the coil 2. Here, "faces" means that each end core portion 31, 32 and each end face 2a, 2b of the coil 2 face each other. The first end core portion 31 and the second end core portion 32 are arranged at intervals in the X direction so as to sandwich both end faces 2a, 2b of the coil 2.

[0064] The shape of each of the first end core portion 31 and the second end core portion 32 is not particularly limited as long as a predetermined magnetic path is formed. As shown in FIG. 2, the shapes of both end core portions 31, 32 of the present embodiment are substantially rectangular parallelepiped shapes. The widths of the first end core portion 31 and the second end core portion 32 may be the same or different. In the present embodiment, the width W 31 of the first end core portion 31 32 and the width W

[0065] 〈First Side Core Portion · Second Side Core Portion〉 The first side core part 33 and the second side core part 34 are parts of the magnetic core 3 that are arranged outside the coil 2 so as to sandwich the middle core part 30. That is, the first side core part 33 and the second side core part 34 are arranged at intervals in the Y direction so as to sandwich both side surfaces along the axial direction of the coil 2. In the present embodiment, as shown in FIG. 3, when viewed from the Z direction, among the two side core parts 33, 34, the side core part arranged on one side in the Y direction, that is, the upper side of the paper surface, is defined as the first side core part 33, and the side core part arranged on the other side in the Y direction, that is, the lower side of the paper surface, is defined as the second side core part 34. The axial direction of each of the first side core part 33 and the second side core part 34 is parallel to the axial direction of the middle core part 30.

[0066] The first side core part 33 and the second side core part 34 only need to have a length that connects the first end core part 31 and the second end core part 32. The shape of each side core part 33, 34 is not particularly limited. As shown in FIG. 2, the shapes of the two side core parts 33, 34 in the present embodiment are each substantially rectangular parallelepiped. The lengths of the first side core part 33 and the second side core part 34 may be the same or different. In the present embodiment, the lengths of the first side core part 33 and the second side core part 34 are the same and are also the same as the length of the middle core part 30. The length of the middle core part 30 is the total length of the first middle core part 30a and the second middle core part 30b. When the middle core part 30 has the above-mentioned gap part, the length of the middle core part 30 is the total length of each middle core part 30a, 30b excluding the gap part. The lengths of each of the middle core part 30, the first side core part 33, and the second side core part 34 are the same as the distance between the opposing surfaces of the first end core part 31 and the second end core part 32.

[0067] The widths of each of the first side core portion 33 and the second side core portion 34 may be equal or different. In the present embodiment, the widths of the first side core portion 33 and the second side core portion 34 are equal. Also, the total width of the width of the first side core portion 33 and the width of the second side core portion 34 is equal to the width of the middle core portion 30. That is, the total cross-sectional area of the cross-sectional area of the first side core portion 33 and the cross-sectional area of the second side core portion 34 is equal to the cross-sectional area of the middle core portion 30.

[0068] At least one of the first side core portion 33 and the second side core portion 34 may be divided in the X direction or may not be divided. Neither of the side core portions 33, 34 in the present embodiment is divided.

[0069] When the middle core portion 30 has the gap portion described above, the middle core portion 30 is shorter than the both side core portions 33, 34. By the total length of the first middle core portion 30a and the second middle core portion 30b being shorter than the lengths of the both side core portions 33, 34, a gap serving as a gap portion can be provided between the first middle core portion 30a and the second middle core portion 30b.

[0070] (First Core · Second Core) As shown in FIGS. 2 and 3, the magnetic core 3 is an assembly combining a first core 3a and a second core 3b. The magnetic core 3 is configured by combining the first core 3a and the second core 3b in the X direction. The shape of each of the first core 3a and the second core 3b can be selected from various combinations. The magnetic core 3 of the present embodiment is an E-T type combining an E-shaped first core 3a and a T-shaped second core 3b.

[0071] 〈First Core〉 The first core 3a includes a first end core portion 31, at least a part of the middle core portion 30, and at least a part of both side core portions 33 and 34 including the first side core portion 33 and the second side core portion 34. In the present embodiment, as shown in FIG. 3, the first core 3a includes all of each of the first side core portion 33 and the second side core portion 34. Further, the first core 3a includes a first middle core portion 30a which is a part of the middle core portion 30. The first end core portion 31, the first middle core portion 30a, the first side core portion 33, and the second side core portion 34 are integrally formed. The first middle core portion 30a extends in the X direction from the middle portion in the Y direction of the first end core portion 31 toward the second middle core portion 30b. The first side core portion 33 and the second side core portion 34 extend in the X direction from both end portions in the Y direction of the first end core portion 31 toward the second end core portion 32. The shape of the first core 3a is E-shaped when viewed from the Z direction.

[0072] As shown in FIG. 3, each of the first side core portion 33 and the second side core portion 34 of the first core 3a has a tip surface 3af facing the second core 3b. As shown in FIG. 2, the shape of the tip surface 3af when viewed from the X direction is rectangular. The tip surface 3af has a first chamfered portion 41 which will be described later.

[0073] 〈Second Core〉 The second core 3b may include a second end core portion 32, the remaining part of the middle core portion 30, and the remaining part of each of the first side core portion 33 and the second side core portion 34. In the present embodiment, as shown in FIG. 3, the second core 3b does not include both side core portions 33 and 34. The second core 3b includes a second middle core portion 30b which is the remaining part of the middle core portion 30. The second end core portion 32 and the second middle core portion 30b are integrally formed. The second middle core portion 30b extends in the X direction from the middle portion in the Y direction of the second end core portion 32 toward the first middle core portion 30a. The shape of the second core 3b is T-shaped when viewed from the Z direction.

[0074] The surface of the second core 3b has an opposing surface 3bf facing the tip surface 3af of the first core 3a in the X direction. That is, the opposing surface 3bf is a region of the surface of the second core 3b that overlaps with the tip surface 3af in the X direction. In the present embodiment, the opposing surface 3bf is provided in the second end core portion 32 of the second core 3b. The opposing surface 3bf includes a contact region that comes into contact with the tip surface 3af and a non-contact region that faces without coming into contact with the surface formed by the first chamfered portion 41 on the tip surface 3af.

[0075] (Positional relationship between the tip surface and the opposing surface) The front end face 3af and the opposing face 3bf satisfy a specific positional relationship. In the present embodiment, as shown in FIG. 4, the outer edge 3bo of the opposing face 3bf is aligned with the outer edge 3ao of the front end face 3af in the Y direction, and the inner edge 3bi of the opposing face 3bf and the inner edge 3ai of the front end face 3af are substantially aligned in the Y direction. In other words, the outer edge 3bo of the opposing face 3bf and the outer edge 3ao of the front end face 3af, and the inner edge 3bi of the opposing face 3bf and the inner edge 3ai of the front end face 3af are not substantially displaced in the Y direction, respectively. FIG. 4 is an enlarged view of the vicinity of the front end face 3af and the opposing face 3bf on the first side core portion 33 side as viewed from the Z direction. In FIG. 4, only the first side core portion 33 side is illustrated, but the second side core portion 34 side shown in FIG. 3 has the same configuration. Also, in FIG. 4, for convenience of explanation, the front end face 3af and the opposing face 3bf are shown separated from each other, but actually they are in contact with each other. This point is the same for FIGS. 6 to 8 respectively referred to in Modification Examples 1-1 to 1-3 described later. Here, the outer edge means the edge on the outer side in the Y direction. The inner edge means the edge on the inner side in the Y direction. The outer side in the Y direction means the side away from the middle core portion 30 in the Y direction. The inner side in the Y direction means the side approaching the middle core portion 30 in the Y direction. The outer edge 3ao of the front end face 3af or the outer edge 3bo of the opposing face 3bf is the edge on the side farther from the middle core portion 30 (FIG. 3) as viewed from the Z direction among the edges constituting the front end face 3af or the opposing face 3bf. The inner edge 3ai of the front end face 3af or the inner edge 3bi of the opposing face 3bf is the edge on the side closer to the middle core portion 30 (FIG. 3) as viewed from the Z direction among the edges constituting the front end face 3af or the opposing face 3bf. The above-mentioned "the outer edge 3bo of the opposing face 3bf is aligned with the outer edge 3ao of the front end face 3af in the Y direction" means that the outer edge 3bo and the outer edge 3ao are not displaced in the Y direction, and as viewed from the Z direction, the Y-direction positions of the outer edge 3bo and the outer edge 3ao coincide with each other. The above-mentioned "the inner edge 3bi of the opposing face 3bf and the inner edge 3ai of the front end face 3af are substantially aligned" means that the displacement in the Y direction between the inner edge 3bi and the inner edge 3ai is 10% or less, and further 5% or less of the width Ws1 of the front end face 3af.When the second end core portion 32 has the opposing surface 3bf as in the present embodiment, the inner edge 3bi of the opposing surface 3bf is located on the extension line obtained by extending the inner edge 3ai of the front end surface 3af in the X direction, as shown in FIG. 4. Therefore, the inner edge 3bi and the inner edge 3ai are not displaced in the Y direction and are aligned in the Y direction. That is, when viewed from the Z direction, the inner edge 3bi and the inner edge 3ai coincide in the Y direction.

[0076] Unlike the present embodiment, the outer edge 3bo of the opposing surface 3bf may be located inside the outer edge 3ao of the front end surface 3af in the Y direction. The phrase "located inside in the Y direction" means that the outer edge 3bo and the outer edge 3ao are not aligned in the Y direction, and when viewed from the Z direction, the outer edge 3bo is displaced inside the outer edge 3ao in the Y direction. The configuration in which the outer edge 3bo is located inside the outer edge 3ao in the Y direction will be described with reference to FIG. 7 in Modification 1-2 described later.

[0077] (First chamfered portion) The front end surface 3af has a first chamfered portion 41. The first chamfered portion 41 is formed on the edge along the Z direction among the edges constituting the front end surface 3af. The first chamfered portion 41 includes at least the first outer chamfered portion 41o. The first outer chamfered portion 41o is connected to the outer edge 3ao of the front end surface 3af. The first inner chamfered portion 41i is connected to the inner edge 3ai of the front end surface 3af. The first chamfered portion 41 only needs to have at least the first outer chamfered portion 41o, and the first inner chamfered portion 41i may not be present. In the present embodiment, the chamfer width of the first inner chamfered portion 41i is substantially zero. In FIGS. 3 and 4, for convenience of explanation, the inner edge 3ai (FIG. 4) of the front end surface 3af is shown as the first inner chamfered portion 41i, but actually the first inner chamfered portion 41i does not exist. That is, in the present embodiment, the front end surface 3af has only the first outer chamfered portion 41o. The configuration having both the first outer chamfered portion 41o and the first inner chamfered portion 41i will be described with reference to FIG. 6 in Modification 1-1 described later.

[0078] Each chamfer of the first outer chamfer portion 41o and the first inner chamfer portion 41i may be a rounded chamfer or a flat chamfer. A rounded chamfer means that, when viewed from the Z direction, the shape of the chamfer portion is arc-shaped. A flat chamfer means that, when viewed from the Z direction, the shape of the chamfer portion is linear. The first outer chamfer portion 41o of the present embodiment is a rounded chamfer.

[0079] The tip surface 3af includes the surface formed by the first chamfer portion 41. That is, the surfaces formed by the respective chamfers of the first outer chamfer portion 41o and the first inner chamfer portion 41i are also part of the tip surface 3af. The tip surface 3af includes a contact region that comes into contact with the opposing surface 3bf of the second core 3b and a non-contact region that faces each other without contacting the opposing surface 3bf. In the present embodiment, the tip surface 3af has a plane along the Y direction and an arc surface formed by the first outer chamfer portion 41o. Among the tip surface 3af, the above-mentioned plane is a surface including the contact region that comes into contact with the opposing surface 3bf of the second core 3b. The surface formed by the first outer chamfer portion 41o is a non-contact region that does not come into contact with the opposing surface 3bf. The surface formed by the first outer chamfer portion 41o is connected to the outer edge 3ao from the above-mentioned plane. In other words, as shown in FIGS. 3 and 4, the first outer chamfer portion 41o connects the above-mentioned plane of the tip surface 3af to the outer surfaces of each of the first side core portion 33 and the second side core portion 34. The outer edge 3ao is a boundary edge between the tip surface 3af and the outer surfaces of the side core portions 33 and 34. The outer surfaces of the side core portions 33 and 34 are the outer surfaces in the Y direction of the side core portions 33 and 34, that is, the surfaces located on the side opposite to the middle core portion 30 side. Depending on the length of the width Ws2 of the opposing surface 3bf described later, the above-mentioned plane of the tip surface 3af may include a non-contact region. Also, depending on the chamfer width of the second chamfer portion 42 (FIGS. 8 and 15) provided on the opposing surface 3bf, specifically, the respective chamfer widths F 21 , F 22 of the second outer chamfer portion 42o and the second inner chamfer portion 42i, the above-mentioned plane may include a non-contact region.

[0080] The chamfer width of the first outer chamfer portion 41o is larger than the chamfer width of the first inner chamfer portion 41i. The chamfer width referred to here means the width of the chamfer portion in the Y direction. As shown in FIG. 4, the chamfer width F 11 of the first outer chamfer portion 41o is the distance along the Y direction between one end of the first outer chamfer portion 41o connected to the outer edge 3ao of the tip surface 3af and the other end on the opposite side. When there is no first inner chamfer portion 41i, that is, when the chamfer width of the first inner chamfer portion 41i is substantially zero as in the present embodiment, it is assumed that the chamfer width of the first outer chamfer portion 41o satisfies being larger than the chamfer width of the first inner chamfer portion 41i.

[0081] Since the chamfer width of the first outer chamfer portion 41o is larger than the chamfer width of the first inner chamfer portion 41i, loss can be reduced. The reason for reducing the loss will be described with reference to FIG. 4. In FIG. 4, the thick dashed arrows indicate the flow of magnetic flux. When magnetic flux flows through the magnetic core 3 (FIG. 3), in the first side core portion 33 and the second side core portion 34, the magnetic flux becomes dense inside in the Y direction in each side core portion 33, 34, and becomes sparser toward the outside in the Y direction. This is because generally magnetic flux flows so that the magnetic path becomes shorter. Also, the magnetic flux flowing through the first core 3a and the second core 3b tries to flow inside both cores 3a, 3b. When magnetic flux passes between the tip surface 3af of the first core 3a and the opposing surface 3bf of the second core 3b, if the first chamfer portion 41 is formed on the tip surface 3af, a part of the magnetic flux will detour between the first core 3a and the second core 3b. As shown in FIG. 4, the magnetic flux flowing outside the first side core portion 33 will detour due to the first outer chamfer portion 41o. However, since there is little magnetic flux flowing outside in the first place, the magnetic flux itself that detours due to the first outer chamfer portion 41o is small. Therefore, even if the chamfer width of the first outer chamfer portion 41o is large, the influence on the magnetic flux flowing through the first core 3a and the second core 3b is small or almost none. Also, as in this embodiment, if the chamfer width of the first inner chamfer portion 41i is zero, the magnetic flux flowing inside the first side core portion 33 will not detour due to the first inner chamfer portion 41i. That is, the magnetic flux flowing inside does not detour and smoothly flows between the first core 3a and the second core 3b. Therefore, since the flow of magnetic flux is hardly obstructed between the first core 3a and the second core 3b, loss can be reduced.

[0082] On the other hand, as in the comparative core shown in FIG. 5, when the tip surface 3af has both the first outer chamfer portion 41o and the first inner chamfer portion 41i and the chamfer widths of the first outer chamfer portion 41o and the first inner chamfer portion 41i are the same, loss is likely to occur. This is because the magnetic flux flowing inside the first side core portion 33 greatly detours due to the first inner chamfer portion 41i. Therefore, since the flow of magnetic flux is obstructed between the first core 3a and the second core 3b, loss occurs.

[0083] Chamfer width F of the first outer chamfer portion 41o 11 is, for example, 10% or more and 45% or less, and further 20% or more and 40% or less of the width Ws1 of the tip surface 3af. The chamfer width F of the first outer chamfer portion 41o 11 The larger the chamfer width F of the first outer chamfer portion 41o is, the smaller the volume of the first core 3a becomes, so that the weight of the first core 3a can be reduced. That is, weight reduction of the magnetic core 3 can be expected. The chamfer width F of the first outer chamfer portion 41o 11 being 10% or more of the width Ws1 of the tip surface 3af makes it easy to reduce the weight of the magnetic core 3. Also, the chamfer width F of the first outer chamfer portion 41o 11 being 45% or less of the width Ws1 of the tip surface 3af makes it easy to secure the contact area between the tip surface 3af and the opposing surface 3bf. By securing the contact area between the tip surface 3af and the opposing surface 3bf, magnetic flux easily flows between the first core 3a and the second core 3b. Therefore, it is easy to reduce losses. The chamfer width F of the first outer chamfer portion 41o 11 Specific numerical values of the chamfer width F depend on the width Ws1 of the tip surface 3af, but are, for example, 2.4 mm or more and 6 mm or less, and further 3 mm or more and 5 mm or less.

[0084] In the present embodiment, the chamfer width of the first inner chamfer portion 41i is substantially zero. The above "substantially zero" means that the chamfer width is less than 1 mm. Details of the chamfer width of the first inner chamfer portion 41i will be described with reference to FIG. 6 in Modification Example 1-1 described later.

[0085] (Relationship between the widths of the opposing surface and the tip surface) In the present embodiment, the width Ws2 of the opposing surface 3bf and the width Ws1 of the tip surface 3af are equal. The width Ws2 of the opposing surface 3bf may be shorter than the width Ws1 of the tip surface 3af. A configuration in which the width Ws2 of the opposing surface 3bf is shorter than the width Ws1 of the tip surface 3af will be described with reference to FIG. 7 in Modification Example 1-2 described later.

[0086] (Relationship between the relative permeabilities of the first core and the second core) The first core 3a and the second core 3b may have the same relative permeability or different relative permeabilities. In the present embodiment, the relative permeability of the second core 3b is higher than that of the first core 3a. By having different relative permeabilities between the first core 3a and the second core 3b, the magnetic characteristics of the entire magnetic core 3 can be adjusted. Therefore, as in the present embodiment, it is easy to obtain a predetermined inductance even without providing a gap portion in the magnetic core 3. Even when the relationship between the relative permeabilities of the first core 3a and the second core 3b satisfies the above relationship, a gap portion may be provided as necessary.

[0087] The relative permeability of each of the first core 3a and the second core 3b can be set as appropriate. For example, the relative permeability of the first core 3a may be 5 or more and 50 or less. For example, the relative permeability of the second core 3b may be 50 or more and 500 or less. If the relative permeabilities of the first core 3a and the second core 3b are within the above respective ranges, it is easy to obtain a predetermined inductance. The relative permeability of the first core 3a may further be 10 or more and 45 or less, or 15 or more and 40 or less. The relative permeability of the second core 3b may further be 100 or more, or 150 or more.

[0088] The relative permeability can be obtained as follows. Ring-shaped measurement samples are cut out from each of the first core 3a and the second core 3b. Windings with 300 turns on the primary side and 20 turns on the secondary side are applied to each of the above measurement samples. The B-H initial magnetization curve is measured in the range of H = 0 (Oe) or more and 100 (Oe) or less, and the maximum value of B / H of this B-H initial magnetization curve is obtained. This maximum value is taken as the relative permeability. The magnetization curve referred to here is the so-called DC magnetization curve.

[0089] (Material) The first core 3a and the second core 3b are formed of a molded body. Examples of the molded body include a compacted powder body, a molded body of a composite material, and the like. The first core 3a and the second core 3b may be molded bodies of the same material as each other, or may be molded bodies of different materials from each other. Different materials from each other include not only the case where the materials of the individual components constituting the first core 3a and the second core 3b are different, but also the case where the materials of the components are the same, but the contents of the components are different. For example, even if the first core 3a and the second core 3b are formed of a compacted powder body, if the material or content of the soft magnetic powder constituting the compacted powder body is different, they are materials different from each other. Also, even if the first core 3a and the second core 3b are formed of a molded body of a composite material, if the material or content of the soft magnetic powder constituting the composite material is different, they are materials different from each other.

[0090] The compacted powder body is obtained by compression molding a raw material powder containing a soft magnetic powder. The compacted powder body can have a higher content of the soft magnetic powder than the molded body of the composite material. Therefore, the compacted powder body is likely to have enhanced magnetic properties. Examples of the magnetic properties include relative permeability and saturation magnetic flux density. The compacted powder body may contain a binder resin, a molding aid, and the like. The content of the magnetic powder in the compacted powder body may be, for example, 85% by volume or more and 99.99% by volume or less when the compacted powder body is 100% by volume.

[0091] The composite material is formed by dispersing soft magnetic powder in a resin. The molded body of the composite material is obtained by filling a mold with a fluid material in which soft magnetic powder is dispersed in an uncured resin and curing the resin. The composite material can easily adjust the content of the soft magnetic powder. Therefore, the composite material is likely to adjust the magnetic properties. The content of the soft magnetic powder in the composite material may be, for example, 20% by volume or more and 80% by volume or less when the composite material is 100% by volume.

[0092] The particles constituting the soft magnetic powder include particles of soft magnetic metals, coated particles having an insulating coating on the outer periphery of the soft magnetic metal particles, particles of soft magnetic non-metals, and the like. Examples of the soft magnetic metal include pure iron and iron-based alloys. Examples of the iron-based alloys include Fe (iron)-Si (silicon) alloys, Fe-Ni (nickel) alloys, and the like. Examples of the insulating coating include phosphates. Examples of the soft magnetic non-metal include ferrite.

[0093] Examples of the resin of the composite material include thermosetting resins and thermoplastic resins. Examples of the thermosetting resins include unsaturated polyester resins, epoxy resins, urethane resins, silicone resins, and the like. Examples of the thermoplastic resins include polyphenylene sulfide resins, polytetrafluoroethylene resins, liquid crystal polymers, polyamide resins, polybutylene terephthalate resins, acrylonitrile-butadiene-styrene resins, and the like. Examples of the polyamide resins include nylon 6, nylon 66, nylon 9T, and the like. In addition, BMC (Bulk molding compound) in which calcium carbonate or glass fiber is mixed with an unsaturated polyester, millable silicone rubber, millable urethane rubber, and the like can also be used.

[0094] The composite material may contain a filler in addition to the soft magnetic powder and the resin. Examples of the filler include ceramic fillers such as alumina and silica. By containing the filler in the composite material, the heat dissipation property can be enhanced. Examples of the content of the filler include 0.2 mass% or more and 20 mass% or less, further 0.3 mass% or more and 15 mass% or less, 0.5 mass% or more and 10 mass% or less when the composite material is 100% by volume.

[0095] The content of the soft magnetic powder in the compacted powder compact or the composite material compact is regarded as equivalent to the area ratio of the soft magnetic powder in the cross section of the compact. The content of the soft magnetic powder is obtained as follows. The cross section of the compact is observed with a scanning electron microscope (SEM) to obtain an observation image. The magnification of the SEM is, for example, 200 times or more and 500 times or less. The number of observation images obtained is 10 or more. The total cross-sectional area is 0.1 cm 2Assume the above. One observation image may be acquired for each cross-section, or multiple observation images may be acquired for each cross-section. Each acquired observation image is subjected to image processing to extract the contour of the particles. Examples of the image processing include binarization processing. The area ratio of the soft magnetic particles is calculated for each observation image, and the average value of the area ratios is obtained. This average value is regarded as the content of the soft magnetic powder.

[0096] In this embodiment, the first core 3a and the second core 3b are formed bodies of different materials. Specifically, the first core 3a is a formed body of a composite material, and the second core 3b is a compacted formed body. Since the first core 3a is composed of a formed body of a composite material and the second core 3b is composed of a compacted formed body, the magnetic characteristics of the entire magnetic core can be adjusted. Therefore, as in this embodiment, it is easy to obtain a predetermined inductance without providing a gap portion in the magnetic core 3. Further, when the first core 3a is composed of a formed body of a composite material and the second core 3b is composed of a compacted formed body, it is easy to make the relative permeability of the second core 3b higher than the relative permeability of the first core 3a. In this embodiment, the relative permeability of the first core 3a is 20, and the relative permeability of the second core 3b is 150.

[0097] (Size) For example, when the reactor 1 is for in-vehicle use, as shown in FIG. 1, the size of the magnetic core 3 is as follows. 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. The height H of the magnetic core 3 in the Z direction is, for example, 15 mm or more and 75 mm or less. In this embodiment, the width W of the magnetic core 3 corresponds to the widths W 31 , W 32 of the first end core portion 31 and the second end core portion 32.

[0098] Also, the size of the main part of the magnetic core 3 is as follows. The width of the middle core part 30, that is, the widths of the first middle core part 30a and the second middle core part 30b are, for example, 10 mm or more and 50 mm or less. The lengths of the first end core part 31 and the second end core part 32 are, for example, 5 mm or more and 40 mm or less. The widths of the first side core part 33 and the second side core part 34 are, for example, 5 mm or more and 40 mm or less. The widths of the first side core part 33 and the second side core part 34 correspond to the width Ws1 of the front end face 3af. The size of each core part is related to the size of the magnetic circuit area of the magnetic core 3.

[0099] (Others) As other configurations, the reactor 1 may include at least one of a case, an adhesive layer, a holding member, and a molded resin part. The case is a member that houses the combination of the coil 2 and the magnetic core 3 inside. The combination housed in the case may be embedded by a sealing resin part. The adhesive layer fixes the above combination to the mounting surface, the inner bottom surface of the case for the above combination, the case to the mounting surface, etc. The holding member is a member interposed between the coil 2 and the magnetic core 3 to ensure electrical insulation between the coil 2 and the magnetic core 3. The molded resin part integrates the coil 2 and the magnetic core 3 by covering the outer periphery of the above combination.

[0100] [Operation and Effect] The reactor 1 of Embodiment 1 can reduce losses. This is because the chamfer width F of the first outer chamfer part 41o 11 is larger than the chamfer width of the first inner chamfer part 41i. Since the chamfer width F of the first outer chamfer part 41o 11 is larger than the chamfer width of the first inner chamfer part 41i, compared with the configuration shown in FIG. 5 where the chamfer widths of the chamfer parts 41o and 41i on both sides are the same, the flow of magnetic flux is less likely to be inhibited between the first core 3a and the second core 3b. Therefore, the loss due to the inhibition of the flow of magnetic flux can be reduced.

[0101] In particular, the chamfer width F of the first outer chamfer part 41o 11is within a specific range, and by setting the chamfer width of the first inner chamfer portion 41i within a specific range, losses can be effectively reduced.

[0102] The reactor 1 has the first core 3a composed of a molded body of a composite material and the second core 3b composed of a compacted molded body, making it easy to set the relative permeability of each of the first core 3a and the second core 3b within a predetermined range. Also, if the first core 3a is composed of a molded body of a composite material and the second core 3b is composed of a compacted molded body, it is easy to obtain a predetermined inductance without providing a gap portion in the magnetic core 3.

[0103] [Modification Example 1-1] Referring to FIG. 6, a modification example of the reactor 1 of Embodiment 1 will be described. Modification Example 1-1 is different from Embodiment 1 in that the tip surface 3af has both a first outer chamfer portion 41o and a first inner chamfer portion 41i as the first chamfer portion. In FIG. 6, only the first side core portion 33 side is shown, but the second side core portion 34 side shown in FIG. 3 has the same configuration. In FIG. 6, the thick dashed arrows indicate the flow of magnetic flux. The following description will focus on the differences from Embodiment 1. The description of the same configuration as Embodiment 1 may be omitted.

[0104] In this example, it has both a first outer chamfer portion 41o and a first inner chamfer portion 41i. Each of the first outer chamfer portion 41o and the first inner chamfer portion 41i of this example is a rounded chamfer. Different from this example, each of the first outer chamfer portion 41o and the first inner chamfer portion 41i may be a flat chamfer. The shapes of the chamfer portions of the first outer chamfer portion 41o and the first inner chamfer portion 41i may be the same or different. For example, one of the first outer chamfer portion 41o and the first inner chamfer portion 41i may be a rounded chamfer and the other may be a flat chamfer.

[0105] The tip surface 3af includes the surface formed by each chamfered portion of the first outer chamfered portion 41o and the first inner chamfered portion 41i. In this example, the tip surface 3af has a plane along the Y direction, an arc surface formed by the first outer chamfered portion 41o, and an arc surface formed by the first inner chamfered portion 41i. The surface formed by the first inner chamfered portion 41i is a non-contact area that does not come into contact with the opposing surface 3bf of the second core 3b. The surface formed by the first inner chamfered portion 41i is connected to the inner edge 3ai from the above-mentioned plane. In other words, the first inner chamfered portion 41i connects the plane along the Y direction of the tip surface 3af and the inner surface of the first side core portion 33. The inner edge 3ai is the boundary edge between the tip surface 3af and the inner surface of the first side core portion 33. The inner surface of the first side core portion 33 is the inner surface in the Y direction in the first side core portion 33, that is, the surface located on the side of the middle core portion 30 shown in FIG. 3.

[0106] The chamfer width F of the first outer chamfered portion 41o 11 is the chamfer width F of the first inner chamfered portion 41i 12 and is larger. In other words, the chamfer width F 12 is smaller than the chamfer width F 11 . The chamfer width F of the first inner chamfered portion 41i 12 is the distance along the Y direction between one end of the first inner chamfered portion 41i connected to the inner edge 3ai of the tip surface 3af and the other end on the opposite side.

[0107] As shown in FIG. 6, when magnetic flux passes between the tip surface 3af of the first core 3a and the opposing surface 3bf of the second core 3b, the magnetic flux flowing inside the first side core portion 33 will go around through the first inner chamfered portion 41i. However, since the chamfer width F of the first inner chamfered portion 41i 12 is smaller than the chamfer width F of the first outer chamfered portion 41o 11 , the chamfer widths F of the first outer chamfered portion 41o and the first inner chamfered portion 41i 11 ,F 12Compared with the configuration shown in FIG. 5 where they are the same, the magnetic flux that detours due to the first inner chamfer 41i is less. Therefore, the magnetic flux flowing inward flows relatively smoothly between the first core 3a and the second core 3b. Accordingly, since it is difficult to inhibit the flow of magnetic flux between the first core 3a and the second core 3b, losses can be reduced.

[0108] Chamfer width F of the first inner chamfer 41i 12 is, for example, 12.5% or less, further 10% or less, 5% or less of the width Ws1 of the tip surface 3af. The chamfer width F of the first inner chamfer 41i 12 being 12.5% or less of the width Ws1 of the tip surface 3af makes it easy to suppress the magnetic flux from detouring due to the first inner chamfer 41i. Therefore, it is easy to suppress the occurrence of losses due to the flow of magnetic flux between the first core 3a and the second core 3b being inhibited. Further, if the chamfer width F of the first inner chamfer 41i 12 is 12.5% or less of the width Ws1 of the tip surface 3af, it is easy to secure the contact area between the tip surface 3af and the opposing surface 3bf. By securing the contact area between the tip surface 3af and the opposing surface 3bf, magnetic flux easily flows between the first core 3a and the second core 3b. Accordingly, it is easy to reduce losses. The chamfer width F of the first inner chamfer 41i 12 is specifically 2 mm or less, further 1.5 mm or less, 1 mm or less. The chamfer width F of the first inner chamfer 41i 12 may be zero.

[0109] [Modification 1-2] With reference to FIG. 7, a modification of the reactor 1 of Embodiment 1 will be described. Modification 1-2 is different from Embodiment 1 in that the width Ws2 of the opposing surface 3bf is shorter than the width Ws1 of the tip surface 3af. In FIG. 7, only the first side core portion 33 side is illustrated, but the second side core portion 34 side shown in FIG. 3 has the same configuration. In FIG. 7, the thick dashed arrows indicate the flow of magnetic flux. The following description will focus on the differences from Embodiment 1. The description of the same configuration as in Embodiment 1 may be omitted.

[0110] (Positional relationship between the tip surface and the opposing surface) In this example, the positional relationship between the front end face 3af and the opposing face 3bf is set as follows. As shown in FIG. 7, the outer edge 3bo of the opposing face 3bf is located inside in the Y direction from the outer edge 3ao of the front end face 3af.

[0111] (Relationship between the widths of the opposing face and the front end face) In this example, the width Ws2 of the opposing face 3bf is shorter than the width Ws1 of the front end face 3af. Since the width Ws2 of the opposing face 3bf is shorter than the width Ws1 of the front end face 3af, the volume of the second core 3b becomes smaller compared to the case where the width Ws1 of the front end face 3af and the width Ws2 of the opposing face 3bf are the same. Therefore, since the weight of the second core 3b is reduced, the magnetic core 3 (FIG. 3) can be lightened. As shown in FIG. 7 when viewed from the Z direction, the outer portion of the first side core portion 33 in the Y direction protrudes outward more than the second end core portion 32. Thus, in the magnetic core 3 (FIG. 3), the width W 32 of the second end core portion 32 is 31 shorter than the width W 32 of the first end core portion 31. Specifically, the width W 31 of the second end core portion 32 is shorter than the width W 31 of the first end core portion 31 by the difference in the widths of the front end face 3af and the opposing face 3bf. The width W of the magnetic core 3 corresponds to the width W

[0112] The width Ws2 of the opposing surface 3bf is, for example, 60% or more and 92% or less, further 65% or more and 90% or less, 70% or more and 85% or less of the width Ws1 of the front end surface 3af. When the width Ws2 of the opposing surface 3bf is 60% or more of the width Ws1 of the front end surface 3af, it is easy to secure the contact area between the front end surface 3af and the opposing surface 3bf. By securing the contact area between the front end surface 3af and the opposing surface 3bf, it is easy to set the magnetic flux that can pass between the front end surface 3af and the opposing surface 3bf within a range where they are generally balanced. If the magnetic flux is within such a balanced range, when a magnetic path is formed in the magnetic core 3 (Fig. 3), the balance of the magnetic flux can be generally maintained between the first core 3a and the second core 3b. Therefore, it becomes possible to maintain electromagnetic performance such as inductance. Since the width Ws2 of the opposing surface 3bf is 92% or less of the width Ws1 of the front end surface 3af, the width Ws2 of the opposing surface 3bf is sufficiently short. Therefore, the weight of the second core 3b can be effectively reduced.

[0113] (Relationship between the relative permeabilities of the first core and the second core) As in this example, when the width Ws2 of the opposing surface 3bf is shorter than the width Ws1 of the front end surface 3af, it is preferable that the relative permeability of the second core 3b is higher than the relative permeability of the first core 3a. That is, assuming the relative permeability of the first core 3a is μr1 and the relative permeability of the second core 3b is μr2, the relationship μr1 < μr2 is satisfied. Since the relative permeability of the second core 3b is higher than the relative permeability of the first core 3a, even if the width Ws2 of the opposing surface 3bf is shorter than the width Ws1 of the front end surface 3af, it is easy to balance the magnetic flux between the front end surface 3af and the opposing surface 3bf. Therefore, the balance of the magnetic flux can be generally maintained between the first core 3a and the second core 3b. Thus, it is possible to make the width Ws2 of the opposing surface 3bf shorter than the width Ws1 of the front end surface 3af while maintaining electromagnetic performance such as inductance.

[0114] Furthermore, it is preferable that the ratio of the relative permeability of the second core 3b to the relative permeability of the first core 3a is 1.1 or more and 12 or less. That is, the relationship of 1.1 ≤ [μr2 / μr1] ≤ 12 is satisfied. When the ratio of the relative permeabilities is 1.1 or more, the relative permeability of the second core 3b is sufficiently higher than the relative permeability of the first core 3a. Therefore, it is possible to make the width Ws2 of the opposing surface 3bf sufficiently shorter than the width Ws1 of the front end surface 3af. When the ratio of the relative permeabilities is 12 or less, it is easy to obtain a predetermined inductance. The ratio of the relative permeabilities may be further 1.5 or more, 2 or more, or 2.5 or more.

[0115] (Relationship between the relative permeability and the width of the front end surface of the first core and the relative permeability and the width of the opposing surface of the second core) When the relative permeability of the first core 3a is μr1, the width of the front end surface 3af is Ws1, the relative permeability of the second core 3b is μr2, and the width of the opposing surface 3bf is Ws2, it is preferable that {(μr1 × Ws1) / (μr2 × Ws2)} satisfies 0.1 or more and 1.6 or less. By the relative permeability μr1 and the width Ws1 and the relative permeability μr2 and the width Ws2 satisfying the above relational expression, the magnetic flux that can pass between the front end surface 3af and the opposing surface 3bf can be set to a range where they are generally balanced. If {(μr1 × Ws1) / (μr2 × Ws2)} is 0.1 or more and 1.6 or less, since it can be said that the magnetic fluxes are in a generally balanced range, the balance of the magnetic fluxes can be generally maintained between the first core 3a and the second core 3b. Therefore, a decrease in inductance can be effectively suppressed. {(μr1 × Ws1) / (μr2 × Ws2)} may be further 0.1 or more and 1.4 or less, or 0.15 or more and 1.2 or less.

[0116] In Modification 1-2, since the width Ws2 of the opposing surface 3bf is shorter than the width Ws1 of the front end surface 3af, the magnetic core 3 can be lightened. Therefore, the weight of the reactor can be reduced.

[0117] [Modification 1-3] Referring to FIG. 8, a modified example of the reactor 1 of Embodiment 1 will be described. In Modified Examples 1-3, the difference from Embodiment 1 is that the opposing surface 3bf has the second chamfering portion 42. In FIG. 8, only the first side core portion 33 side is illustrated, but the second side core portion 34 side shown in FIG. 3 has the same configuration. In FIG. 8, the thick dashed arrow indicates the flux flow. The following description will focus on the differences from Embodiment 1. The description of the same configuration as in Embodiment 1 may be omitted.

[0118] (Second Chamfering Portion) The second chamfering portion 42 is formed on the edge along the Z direction among the edges constituting the opposing surface 3bf. The second chamfering portion 42 includes at least the second outer chamfering portion 42o of the second outer chamfering portion 42o and the second inner chamfering portion 42i. The second outer chamfering portion 42o is connected to the outer edge 3bo of the opposing surface 3bf. The second inner chamfering portion 42i is connected to the inner edge 3bi of the opposing surface 3bf. The second chamfering portion 42 only needs to have at least the second outer chamfering portion 42o, and the second inner chamfering portion 42i may not be present. In FIG. 8, for convenience of explanation, the inner edge 3bi of the opposing surface 3bf is shown as the second inner chamfering portion 42i, but actually the second inner chamfering portion 42i does not exist. That is, in this example, the opposing surface 3bf has only the second outer chamfering portion 42o.

[0119] The second outer chamfering portion 42o may be a round chamfer or a flat chamfer. The second outer chamfering portion 42o in this example is a round chamfer.

[0120] The opposing surface 3bf includes the surface formed by the second chamfering portion 42. That is, the surfaces formed by each of the second outer chamfering portion 42o and the second inner chamfering portion 42i are also part of the opposing surface 3bf. In this example, the opposing surface 3bf has a plane along the Y direction and an arc surface formed by the second outer chamfering portion 42o. Among the opposing surface 3bf, the above-mentioned plane is the surface including the contact area that comes into contact with the tip surface 3af. The surface formed by the second outer chamfering portion 42o is a non-contact area that does not come into contact with the tip surface 3af. The surface formed by the second outer chamfering portion 42o is connected from the above-mentioned plane to the outer edge 3bo. In other words, the second outer chamfering portion 42o connects the above-mentioned plane of the opposing surface 3bf and the outer surface of the second end core portion 32. The outer edge 3bo is the boundary edge between the opposing surface 3bf and the outer surface of the second end core portion 32. The outer surface of the second end core portion 32 is the outer end surface of the second end core portion 32 in the Y direction. Depending on the length of the width Ws1 of the tip surface 3af described above, the non-contact area may be included in the above-mentioned plane of the opposing surface 3bf. Also, depending on the chamfering width of the first chamfering portion 41 described above, specifically, the chamfering widths F 11 ,F 12 of the first outer chamfering portion 41o and the first inner chamfering portion 41i, the non-contact area may be included in the above-mentioned plane.

[0121] The chamfering width of the second outer chamfering portion 42o is larger than the chamfering width of the second inner chamfering portion 42i. The chamfering width here refers to the width of the chamfering portion in the Y direction. As shown in FIG. 8, the chamfering width F 21 of the second outer chamfering portion 42o is the distance along the Y direction between one end of the second outer chamfering portion 42o connected to the outer edge 3bo of the opposing surface 3bf and the other end on the opposite side. When, as in this example, there is no second inner chamfering portion 42i, that is, when the chamfering width of the second inner chamfering portion 42i is zero, it is assumed that the chamfering width of the second outer chamfering portion 42o satisfies being larger than the chamfering width of the second inner chamfering portion 42i.

[0122] The chamfering width F 21 of the second outer chamfering portion 42o is the chamfering width F 11The following can be mentioned. The chamfer width F of the second outer chamfer portion 42o 21 is the chamfer width F of the first outer chamfer portion 41o 11 By being the following, it is possible to avoid the magnetic flux from making a detour by the second outer chamfer portion 42o. Therefore, it is easy to suppress the occurrence of loss due to the flow of the magnetic flux being inhibited between the first core 3a and the second core 3b. Further, the chamfer width F of the second outer chamfer portion 42o 21 is the chamfer width F of the first outer chamfer portion 41o 11 If it is the following, it is easy to secure the contact area between the tip surface 3af and the opposed surface 3bf. By securing the contact area between the tip surface 3af and the opposed surface 3bf, the magnetic flux easily flows between the first core 3a and the second core 3b. Therefore, it is easy to suppress the loss. The chamfer width F of the second outer chamfer portion 42o 21 is the chamfer width F of the first outer chamfer portion 41o 11 It may be appropriately set according to the chamfer width F of the first outer chamfer portion 41o, for example, 2.4 mm or more and 6 mm or less, and further 3 mm or more and 5 mm or less.

[0123] In Modifications 1-3, since the opposed surface 3bf has the second outer chamfer portion 42o, weight reduction of the magnetic core 3 (FIG. 3) can be expected. This is because the volume of the second core 3b is reduced by the second outer chamfer portion 42o. Therefore, since the weight of the second core 3b is reduced, the magnetic core 3 can be lightened.

[0124] [Embodiment 2] Referring to FIG. 9, the reactor 1 of Embodiment 2 will be described. The reactor 1 of Embodiment 2 is different from the reactor 1 of Embodiment 1 in that the magnetic core 3 is of an E-I type. The following description will focus on the differences from Embodiment 1. The description of the same configuration as that of Embodiment 1 may be omitted.

[0125] The first core 3a includes the first end core portion 31, all of the middle core portion 30, and all of each of the first side core portion 33 and the second side core portion 34. The middle core portion 30 extends in the X direction from the intermediate portion in the Y direction of the first end core portion 31 toward the second end core portion 32. The shape of the first core 3a is E-shaped. The first core 3a is a molded body of a composite material.

[0126] The second core 3b includes only the second end core portion 32. The second core 3b does not include the middle core portion 30, the first side core portion 33, and the second side core portion 34. The shape of the second core 3b is I-shaped. The second core 3b is a compacted powder body.

[0127] In the present embodiment, the end portion of the middle core portion 30 on the second end core portion 32 side is in contact with the second end core portion 32. Therefore, there is substantially no gap between the middle core portion 30 and the second end core portion 32, and no gap portion exists. Different from the present embodiment, it is also possible to provide a gap portion between the middle core portion 30 and the second end core portion 32. When a gap portion is provided between the middle core portion 30 and the second end core portion 32, the middle core portion 30 is shorter than the both side core portions 33, 34. Thereby, a gap serving as a gap portion can be provided between the middle core portion 30 and the second end core portion 32.

[0128] [Operation and Effect] Similar to the reactor 1 of Embodiment 1, the reactor 1 of Embodiment 2 can reduce losses. Further, each configuration of Modification 1-1 to Modification 1-3 described as a modification of Embodiment 1 is applicable to Embodiment 2.

[0129] [Embodiment 3] Referring to FIGS. 10 and 11, the reactor 1 of Embodiment 3 will be described. The reactor 1 of Embodiment 3 is different from the reactor 1 of Embodiment 1 in that the magnetic core 3 is of E-E type. The following description will focus on the differences from Embodiment 1. The description of the same configuration as in Embodiment 1 may be omitted. FIG. 11 is an enlarged view of the vicinity of the front end face 3af and the opposing face 3bf on the first side core portion 33 side as viewed from the Z direction. In FIG. 11, only the first side core portion 33 side is shown, but the second side core portion 34 side shown in FIG. 10 has the same configuration. Further, in FIG. 11, for convenience of explanation, the front end face 3af and the opposing face 3bf are shown separated from each other, but actually they are in contact with each other. This is the same in FIGS. 13 to 15 respectively referred to in Modification 3-1 to Modification 3-3 described later.

[0130] As shown in FIG. 10, each of the first side core portion 33 and the second side core portion 34 of the present embodiment is divided into two in the X direction. The first side core portion 33 has a first portion 33a and a second portion 33b. The second side core portion 34 has a first portion 34a and a second portion 34b. The first portions 33a and 34a are located on one side in the X direction of both side core portions 33 and 34, specifically, on the side of the first end core portion 31. The second portions 33b and 34b are located on the other side in the X direction of both side core portions 33 and 34, specifically, on the side of the second end core portion 32. The widths of the first portions 33a and 34a are equal. The widths of the second portions 33b and 34b are equal. Also, the total width of the first portions 33a and 34a is equal to the width of the middle core portion 30.

[0131] The first portions 33a and 34a are in contact with the second portions 33b and 34b, and there is substantially no gap between the first portions 33a and 34a and the second portions 33b and 34b. That is, both side core portions 33 and 34 do not have a gap portion between the first portions 33a and 34a and the second portions 33b and 34b. The length of each of the first portions 33a and 34a and the second portions 33b and 34b may be appropriately set so as to obtain predetermined magnetic characteristics. The first portions 33a and 34a may be longer or shorter than the second portions 33b and 34b. Also, the lengths of the first portions 33a and 34a may be equal or different. The lengths of the second portions 33b and 34b may be equal or different. In the present embodiment, the first portions 33a and 34a are longer than the second portions 33b and 34b. Also, the lengths of the first portions 33a and 34a are equal. The lengths of the second portions 33b and 34b are equal.

[0132] As shown in FIG. 10, the first core 3a includes a first end core portion 31, a first middle core portion 30a, and first portions 33a and 34a which are each part of the first side core portion 33 and the second side core portion 34. The first end core portion 31, the first middle core portion 30a, and the first portions 33a and 34a of both side core portions 33 and 34 are integrally formed. The first portions 33a and 34a extend in the X direction from both ends in the Y direction of the first end core portion 31 toward the second portions 33b and 34b. The shape of the first core 3a is E-shaped when viewed from the Z direction. The first core 3a is a molded body of a composite material.

[0133] As shown in FIG. 10, each of the first portions 33a and 34a in both side core portions 33 and 34 of the first core 3a has a tip surface 3af facing the second core 3b. The width Ws1 of the tip surface 3af is equal to the width of the first portions 33a and 34a.

[0134] The second core 3b includes a second end core portion 32, a second middle core portion 30b, and second portions 33b and 34b which are the remaining parts of the first side core portion 33 and the second side core portion 34, respectively. The second end core portion 32, the second middle core portion 30b, and the second portions 33b and 34b of both side core portions 33 and 34 are integrally formed. The second portions 33b and 34b extend in the X direction from both ends in the Y direction of the second end core portion 32 toward the first portions 33a and 34a. The shape of the second core 3b is E-shaped when viewed from the Z direction. The second core 3b is a compacted powder molded body.

[0135] In the present embodiment, the facing surface 3bf is provided in each of the second portions 33b and 34b of the first side core portion 33 and the second side core portion 34. The width Ws2 of the facing surface 3bf in the present embodiment is equal to the width of the second portions 33b and 34b.

[0136] The front end surface 3af and the opposing surface 3bf satisfy a specific positional relationship, similar to that in Embodiment 1. Specifically, as shown in FIG. 11, the outer edge 3bo of the opposing surface 3bf is aligned with the outer edge 3ao of the front end surface 3af in the Y direction, and the inner edge 3bi of the opposing surface 3bf and the inner edge 3ai of the front end surface 3af are substantially aligned in the Y direction. In this embodiment, the outer edge 3ao or the inner edge 3ai of the front end surface 3af is the boundary edge between the front end surface 3af and the outer or inner surface of the first portions 33a, 34a. The outer edge 3bo or the inner edge 3bi of the opposing surface 3bf is the boundary edge between the opposing surface 3bf and the outer or inner surface of the second portions 33b, 34b.

[0137] Also, similar to Embodiment 1, the front end surface 3af has a first chamfered portion 41. In this embodiment, the front end surface 3af has only a first outer chamfered portion 41o as the first chamfered portion 41. The chamfer width of the first inner chamfered portion 41i is substantially zero. In FIGS. 10 and 11, for convenience of explanation, the inner edge 3ai (FIG. 11) of the front end surface 3af is shown as the first inner chamfered portion 41i, but actually, the first inner chamfered portion 41i does not exist. The first outer chamfered portion 41o of this embodiment is a rounded chamfer. The first outer chamfered portion 41o connects the plane along the Y direction of the front end surface 3af and the outer surface of the first portions 33a, 34a, as shown in FIGS. 10 and 11.

[0138] Also in this embodiment, since the chamfer width of the first outer chamfer portion 41o is larger than the chamfer width of the first inner chamfer portion 41i, losses can be reduced in the same manner as in Embodiment 1. The reason why losses can be reduced will be described with reference to FIG. 11. In FIG. 11, the thick dashed arrows indicate the flow of magnetic flux. When magnetic flux passes between the tip surface 3af of the first core 3a and the opposing surface 3bf of the second core 3b, if the first chamfer portion 41 is formed on the tip surface 3af, a part of the magnetic flux will take a roundabout path between the first core 3a and the second core 3b. As shown in FIG. 11, the magnetic flux flowing outside the first side core portion 33 will take a roundabout path due to the first outer chamfer portion 41o. As described above, the magnetic flux flowing outside is small in the first place. Therefore, even if the chamfer width of the first outer chamfer portion 41o is large, the influence on the magnetic flux flowing through the first core 3a and the second core 3b is small or almost non-existent. Also, if the chamfer width of the first inner chamfer portion 41i is zero, the magnetic flux flowing inside the first side core portion 33 will not take a roundabout path due to the first inner chamfer portion 41i. That is, the magnetic flux flowing inside flows smoothly between the first core 3a and the second core 3b. Therefore, since the flow of magnetic flux between the first core 3a and the second core 3b is hardly inhibited, losses can be reduced.

[0139] On the other hand, as in the comparative core shown in FIG. 12, when the tip surface 3af has both the first outer chamfer portion 41o and the first inner chamfer portion 41i, and the chamfer widths of the first outer chamfer portion 41o and the first inner chamfer portion 41i are the same, losses are likely to occur. This is because the magnetic flux flowing inside the first side core portion 33 takes a roundabout path due to the first inner chamfer portion 41i. Therefore, since the flow of magnetic flux between the first core 3a and the second core 3b is inhibited, losses occur.

[0140] [Operational Effects] The reactor 1 of Embodiment 3 can reduce losses in the same manner as the reactor 1 of Embodiment 1.

[0141] [Modification Example 3-1] Referring to FIG. 13, a modification of the reactor 1 of Embodiment 3 will be described. Modification 3-1 is different from Embodiment 3 in that the tip surface 3af has both a first chamfered portion 41o as a first outer chamfered portion and a first inner chamfered portion 41i as a first inner chamfered portion. In FIG. 13, only the side of the first side core portion 33 is shown, but the side of the second side core portion 34 shown in FIG. 10 has the same configuration. In FIG. 13, the thick dashed arrow indicates the flow of magnetic flux. Each configuration of the first outer chamfered portion 41o and the first inner chamfered portion 41i is the same as that of Modification 1-1 shown in FIG. 6 described in Embodiment 1. The first inner chamfered portion 41i connects the plane along the Y direction of the tip surface 3af and the inner surface of the first portion 33a.

[0142] [Modification 3-2] Referring to FIG. 14, a modification of the reactor 1 of Embodiment 3 will be described. Modification 3-2 is different from Embodiment 3 in that the outer edge 3bo of the opposing surface 3bf is located inside in the Y direction from the outer edge 3ao of the tip surface 3af, and the width Ws2 of the opposing surface 3bf is shorter than the width Ws1 of the tip surface 3af. In FIG. 14, only the side of the first side core portion 33 is shown, but the side of the second side core portion 34 shown in FIG. 10 has the same configuration. In FIG. 14, the thick dashed arrow indicates the flow of magnetic flux. The positional relationship between the opposing surface 3bf and the tip surface 3af, the relationship between the width Ws2 of the opposing surface 3bf and the width Ws1 of the tip surface 3af, and the relationship between the relative permeability μr1 of the first core 3a and the relative permeability μr2 of the second core 3b are the same as those of Modification 1-2 shown in FIG. 7 described in Embodiment 1. Also, similar to Modification 1-2, the relative permeability μr1 and the width Ws1 and the relative permeability μr2 and the width Ws2 satisfy the above relational expression. That is, {(μr1 × Ws1) / (μr2 × Ws2)} is 0.1 or more and 1.6 or less.

[0143] In this example, as shown in FIG. 14, the width of the first portion 33a corresponds to the width Ws1 of the tip surface 3af, and the width of the second portion 33b corresponds to the width Ws2 of the opposing surface 3bf. Therefore, the width of the second portion 33b is shorter than the width of the first portion 33a. Also, as shown in FIG. 14, when viewed from the Z direction, the outer portion in the Y direction of the first portion 33a protrudes outward more than the second portion 33b. Therefore, in the magnetic core 3 (FIG. 10), the width W of the second end core portion 32 32is the width W of the first end core portion 31 31 is shorter than.

[0144] In Modification 3-2, the width Ws2 of the opposing surface 3bf is shorter than the width Ws1 of the front end surface 3af, so that the volume of the second core 3b is smaller as compared with the case where the width Ws1 of the front end surface 3af and the width Ws2 of the opposing surface 3bf are the same. Therefore, since the weight of the second core 3b is reduced, the magnetic core 3 can be lightened. Thus, the weight of the reactor can be reduced.

[0145] [Modification 3-3] With reference to FIG. 15, a modification of the reactor 1 of Embodiment 3 will be described. Modification 3-3 is different from Embodiment 3, more specifically, Modification 3-1, in that the opposing surface 3bf has the second chamfered portion 42. In FIG. 15, only the first side core portion 33 side is illustrated, but the second side core portion 34 side shown in FIG. 10 has the same configuration. In FIG. 15, the thick dashed arrow indicates the flow of magnetic flux. Each configuration of the first outer chamfered portion 41o and the first inner chamfered portion 41i is the same as that of Modification 1-1 shown in FIG. 6 described in Embodiment 1.

[0146] In this example, the opposing surface 3bf has both a second outer chamfered portion 42o and a second inner chamfered portion 42i as the second chamfered portion 42. Different from this example, the second inner chamfered portion 42i may not be provided. That is, the opposing surface 3bf may have only the second outer chamfered portion 42o. Each of the second outer chamfered portion 42o and the second inner chamfered portion 42i may be a round chamfer or a flat chamfer. Each of the second outer chamfered portion 42o and the second inner chamfered portion 42i in this example is a round chamfer. The shapes of the second outer chamfered portion 42o and the second inner chamfered portion 42i may be the same or different. For example, one of the second outer chamfered portion 42o and the second inner chamfered portion 42i may be a round chamfer and the other may be a flat chamfer.

[0147] The opposing surface 3bf includes the surfaces formed by the chamfered portions of the second outer chamfered portion 42o and the second inner chamfered portion 42i. In this example, the opposing surface 3bf has a plane along the Y direction, an arcuate surface formed by the second outer chamfered portion 42o, and an arcuate surface formed by the second inner chamfered portion 42i. The surface formed by the second outer chamfered portion 42o connects to the outer edge 3bo from the above-mentioned plane. The surface formed by the second inner chamfered portion 42i connects to the inner edge 3bi from the above-mentioned plane. In other words, the second outer chamfered portion 42o connects the above-mentioned plane of the opposing surface 3bf and the outer surface of the second portion 33b. The second inner chamfered portion 42i connects the above-mentioned plane of the opposing surface 3bf and the inner surface of the second portion 33b.

[0148] The chamfer width F of the second outer chamfered portion 42o 21 is larger than the chamfer width F of the second inner chamfered portion 42i 22 That is, the chamfer width F 22 is smaller than the chamfer width F 21 The chamfer width F of the second inner chamfered portion 42i 22 is the distance along the Y direction between one end connected to the inner edge 3bi of the opposing surface 3bf and the other end on the opposite side.

[0149] The chamfer width F of the second inner chamfered portion 42i 22 is, for example, equal to or less than the chamfer width F of the first inner chamfered portion 41i 12 By the chamfer width F of the second inner chamfered portion 42i being equal to or less than the chamfer width F of the first inner chamfered portion 41i 22 it is possible to avoid the magnetic flux from taking a roundabout path through the second inner chamfered portion 42i. Therefore, it is easy to suppress the occurrence of losses due to the flow of the magnetic flux being inhibited between the first core 3a and the second core 3b. Also, if the chamfer width F of the second inner chamfered portion 42i 12 is equal to or less than the chamfer width F of the first inner chamfered portion 41i 22 it is easy to ensure the contact area between the tip surface 3af and the opposing surface 3bf. By ensuring the contact area between the tip surface 3af and the opposing surface 3bf, it is easy for the magnetic flux to flow between the first core 3a and the second core 3b. Therefore, it is easy to suppress losses. The chamfer width F of the second inner chamfered portion 42i 12 If it is equal to or less than the chamfer width F of the first inner chamfered portion 41i22 is the chamfer width F of the first inner chamfered portion 41i 12 which may be appropriately set according to, for example, 2 mm or less, further 1.5 mm or less, and 1 mm or less. The chamfer width F of the second inner chamfered portion 42i 22 may be zero.

[0150] In Modification 3-3, since the opposing surface 3bf has the second inner chamfered portion 42i in addition to the second outer chamfered portion 42o, further weight reduction of the magnetic core 3 (FIG. 10) can be expected. This is because the volume of the second core 3b is reduced by the second outer chamfered portion 42o and the second inner chamfered portion 42i. Therefore, since the weight of the second core 3b is reduced, the magnetic core 3 can be lightened.

[0151] [Embodiment 4] Referring to FIG. 16, the reactor 1 of Embodiment 4 will be described. The reactor 1 of Embodiment 4 is different from the reactor 1 of Embodiment 3 in that the magnetic core 3 is of the E-U type. The following description will focus on the differences from Embodiment 3. The description of the same configuration as in Embodiment 3 may be omitted.

[0152] The first core 3a includes the first end core portion 31, all of the middle core portion 30, and the first portions 33a and 34a of the first side core portion 33 and the second side core portion 34, respectively. The shape of the first core 3a is E-shaped. The first core 3a is a molded body of a composite material.

[0153] The second core 3b Second end core part 32 and the second portions 33b and 34b of the first side core portion 33 and the second side core portion 34, respectively. The second core 3b does not include the middle core portion 30. The shape of the second core 3b is U-shaped. The second core 3b is a compacted molded body.

[0154] In this embodiment, the end of the middle core portion 30 on the side of the second end core portion 32 is in contact with the second end core portion 32. Therefore, there is substantially no gap between the middle core portion 30 and the second end core portion 32, and there is no gap portion. As described in Embodiment 2, it is also possible to provide a gap portion between the middle core portion 30 and the second end core portion 32.

[0155] 〔Function and Effect〕 Similar to the reactor 1 of Embodiment 1, the reactor 1 of Embodiment 4 can reduce losses. Further, each configuration of Modification Examples 3-1 to 3-3 described as a modification of Embodiment 3 is applicable to Embodiment 4.

[0156] [Embodiment 5] 〔Converter - Power Conversion Device〕 The reactors 1 of Embodiments 1 to 4 can be used for applications that satisfy the following energization conditions. Examples of the energization conditions include a maximum direct current of about 100 A or more and 1000 A or less, an average voltage of about 100 V or more and 1000 V or less, and an operating frequency of about 5 kHz or more and 100 kHz or less. The reactors 1 of Embodiments 1 to 4 can typically be used as components of a converter mounted on vehicles such as electric vehicles and hybrid vehicles, or as components of a power conversion device including this converter.

[0157] Vehicles 1200 such as hybrid vehicles and electric vehicles include, as shown in FIG. 17, a main battery 1210, a power conversion device 1100 connected to the main battery 1210, and a motor 1220 that is driven by the supply power from the main battery 1210 and used for traveling. The motor 1220 is typically a three - phase alternating current motor, which drives the wheels 1250 during traveling and functions as a generator during regeneration. In the case of a hybrid vehicle, the vehicle 1200 includes an engine 1300 in addition to the motor 1220. In FIG. 17, an inlet is shown as a charging location of the vehicle 1200, but it can be in a form equipped with a plug.

[0158] The power conversion device 1100 includes a converter 1110 connected to the main battery 1210, and an inverter 1120 connected to the converter 1110 for converting 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 or more and 300V or less, to about 400V or more and 700V or less when the vehicle 1200 is running, and supplies power to the inverter 1120. During regeneration, the converter 1110 steps down the input voltage output from the motor 1220 via the inverter 1120 to a DC voltage compatible with the main battery 1210, and charges the main battery 1210. The input voltage is a DC voltage. When the vehicle 1200 is running, the inverter 1120 converts the DC boosted by the converter 1110 into a predetermined AC and supplies power to the motor 1220. During regeneration, the inverter 1120 converts the AC output from the motor 1220 into DC and outputs it to the converter 1110.

[0159] As shown in FIG. 18, the converter 1110 includes a plurality of switching elements 1111, a drive circuit 1112 for controlling the operation of the switching elements 1111, and a reactor 1115, and converts the input voltage by repeating ON / OFF. Here, the conversion of the input voltage means performing step-up and step-down. As the switching element 1111, a power device such as a field effect transistor or an insulated gate bipolar transistor is used. The reactor 1115 utilizes the property of a coil that attempts to prevent changes in the current flowing through the circuit, and has a function of smoothing the change when the current attempts to increase or decrease due to the switching operation. The reactor 1115 includes the reactor 1 of any one of Embodiments 1 to 4. By providing the low-loss reactor 1, an improvement in efficiency can be expected in the power conversion device 1100 and the converter 1110.

[0160] In addition to the converter 1110, the vehicle 1200 includes a converter 1150 for a power feeding device connected to the main battery 1210, and a converter 1160 for an auxiliary power supply connected to the sub-battery 1230, which is a power source for the auxiliary devices 1240, and the main battery 1210, and converts the high voltage of the main battery 1210 into a low voltage. The converter 1110 typically performs DC-DC conversion, while the converter 1150 for a power feeding device and the converter 1160 for an auxiliary power supply perform AC-DC conversion. Some of the converters 1150 for a power feeding device perform DC-DC conversion. The reactors of the converter 1150 for a power feeding device and the converter 1160 for an auxiliary power supply have the same configuration as any of the reactors 1 from Embodiment 1 to Embodiment 4, and reactors with appropriately changed sizes, shapes, etc. can be used. Also, for a converter that performs conversion of input power, such as a converter that only steps up or a converter that only steps down, any of the reactors 1 from Embodiment 1 to Embodiment 4 can be used.

[0161] <Test Example 1> Regarding the reactor having the same configuration as Embodiment 1 described above, the influence on the electromagnetic performance was evaluated. The sample of the reactor used in Test Example 1 has an E-T type magnetic core 3. The relative permeability μr1 of the first core 3a is 20. The relative permeability μr2 of the second core 3b is 150.

[0162] In Test Example 1, evaluations were performed on Sample No. 1-1 in which the front end face 3af has only the first outer surface machining portion 41o, and Sample No. 10 in which the front end face 3af has the first outer surface machining portion 41o and the first inner surface machining portion 41i. The sizes of the magnetic core 3 and each main part are shown below.

[0163] (Sizes of Magnetic Core and Main Parts) · Length L of magnetic core 3: 70 mm · Width W of magnetic core 3: 75 mm · Height H of magnetic core 3: 30 mm · Width of middle core portion 30 = width of first middle core portion 30a and second middle core portion 30b: 24 mm · Lengths of first end core portion 31 and second end core portion 32: 12.5 mm · Width W of the first end core part 31 and the second end core part 32 31 ,W 32 : 75 mm · Width of the first side core part 33 and the second side core part 34 = width Ws1 of the front end face 3af: 12 mm · Width Ws2 of the opposing face 3bf: 12 mm

[0164] 〈Specimen No. 1-1〉 · Chamfer width F of the first outer chamfer part 41o 11 : 4.5 mm · Chamfer width F of the first inner chamfer part 41i 12 : 0 mm · Chamfer width F with respect to the width Ws1 of the front end face 3af 11 Ratio (F 11 / Ws1): 37.5% · Chamfer width F with respect to the width Ws1 of the front end face 3af 12 Ratio (F 12 / Ws1): 0

[0165] 〈Specimen No. 10〉 · Chamfer width F of the first outer chamfer part 41o 11 : 2.25 mm · Chamfer width F of the first inner chamfer part 41i 12 : 2.25 mm · Chamfer width F with respect to the width Ws1 of the front end face 3af 11 Ratio (F 11 / Ws1): 18.75% · Chamfer width F with respect to the width Ws1 of the front end face 3af 12 Ratio (F 12 / Ws1): 18.75%

[0166] For Specimen No. 1-1, the chamfer width F of the first outer chamfer part 41o 11 is larger than the chamfer width F of the first inner chamfer part 41i 12 . For Specimen No. 10, the chamfer width F of the first outer chamfer part 41o 11 and the chamfer width F of the first inner chamfer part 41i 12 are the same, which is a comparison model.

[0167] (Evaluation of Electromagnetic Performance) Regarding the reactors of each sample, the inductance and losses were analyzed by computer simulation. For the analysis, JMAG-Designer 19.0 manufactured by JSOL Corporation, a commercially available electromagnetic field analysis software, was used. For the inductance analysis, the inductance when a direct current was passed through the coil was determined. The current was varied in the range from 0 A to 400 A. The inductances at current values of 0 A, 100 A, 200 A, and 300 A are shown in Table 1. In Table 1, the inductance at each current value for Sample No. 1-1 is shown as the ratio of the difference to the inductance at each current value for Sample No. 10. This ratio is shown as a percentage with the inductance at each current value for Sample No. 10 set to 100. Also, a graph of the inductance obtained by the analysis is shown in Fig. 19. In the graph of Fig. 19, the horizontal axis represents the current (Amean). In the graph of Fig. 19, the vertical axis represents the inductance (μH). In Fig. 19, the dashed-line graph represents the inductance of Sample No. 10. In Fig. 19, the solid-line graph represents the inductance of Sample No. 1-1.

[0168] For the loss analysis, the total loss when driven under the conditions of a direct current of 0 A, an input voltage of 300 V, an output voltage of 600 V, and a frequency of 20 kHz was determined. The total loss includes the iron loss of the magnetic core and the loss in the coil, etc. The results are shown in Table 1. In Table 1, the total loss of Sample No. 1-1 is shown as the ratio of the difference to the total loss of Sample No. 10. This ratio is shown as a percentage with the loss of Sample No. 10 set to 100.

[0169] (Evaluation of Weight Reduction Effect) Furthermore, for the reactor of Sample No. 1-1, the weight reduction effect of the magnetic core was evaluated. Here, the reduction amount of the volume of the first core in Sample No. 1-1 with respect to the volume of the first core in Sample No. 10 was calculated. The volume reduction amount is obtained by subtracting the volume of the first core of Sample No. 1-1 from the volume of the first core of Sample No. 10. The results are shown in Table 1. Also, the mass ratio of the first core of Sample No. 1-1 to the first core of Sample No. 10 was calculated. The mass ratio indicates the mass of the first core of Sample No. 1-1 as a percentage of the mass of the first core of Sample No. 10. Table 1 also shows the mass ratio.

[0170]

Table 1

[0171] As shown in Table 1 and FIG. 19, the inductance characteristics of Sample No. 1-1 are almost the same as those of Sample No. 10. Specifically, as shown in Table 1, the inductance at each current value from 0 A to 300 A in Sample No. 1-1 is within ±2.5%, further within ±1.5%, and particularly within ±0.5% of the inductance at each current value in Sample No. 10. Therefore, it can be said that Sample No. 1-1 maintains inductance characteristics equivalent to those of Sample No. 10. That is, Sample No. 1-1 can sufficiently maintain a predetermined inductance. Thus, in Sample No. 1-1, the chamfer width of the first outer chamfered portion has almost no influence on the inductance. Also, from the results of Table 1, the loss of Sample No. 1-1 is reduced compared to Sample No. 10.

[0172] Furthermore, Sample No. 1-1 can reduce the weight of the first core by 0.1% compared to Sample No. 10.

[0173] <Test Example 2> In Test Example 2, the chamfer width F of the first outer chamfered portion 41o 11 was changed to examine the influence of the chamfer width F 11 on the electromagnetic performance. Specifically, the chamfer width F of the first outer chamfered portion 41o 11For the reactors of Sample Nos. 2-1 to 2-6 with the setting in the range of 2.4 mm to 6 mm, the same evaluation as in Test Example 1 was performed. Sample No. 2-3 is the same as Sample No. 1-1 in Test Example 1. The difference between Sample Nos. 2-1 to 2-6 is only the chamfer width F 11 of the first outer chamfered portion 41o.

[0174] For the reactors of each sample, the inductance and total loss were determined in the same manner as in Test Example 1. The results are shown in Table 2. In Table 2, the inductance at each current value in Sample Nos. 2-1 to 2-6 is shown as the ratio of the difference to the inductance at each current value in Sample No. 10. The total loss of Sample Nos. 2-1 to 2-6 is shown as the ratio of the difference to the total loss of Sample No. 10. Further, in the same manner as in Test Example 1, Table 2 shows the volume reduction amount and mass ratio of the first core in Sample Nos. 2-1 to 2-6 with respect to the first core in Sample No. 10.

[0175]

Table 2

[0176] As shown in Table 2, the larger the chamfer width F 11 of the first outer chamfered portion is than the chamfer width F 12 of the first inner chamfered portion, the smaller the loss becomes. That is, the loss reduction effect becomes larger. Also, the larger the chamfer width F 11 is, the larger the volume reduction amount of the first core becomes. That is, the weight reduction effect becomes larger. However, if the chamfer width F 11 is made too large, the inductance characteristics tend to deteriorate. Specifically, the variation becomes larger with respect to the inductance at each current value from 0 A to 300 A in Sample No. 10. That is, it becomes difficult to maintain the same inductance characteristics as Sample No. 10. For Sample Nos. 2-1 to 2-5, the variation range of the inductance at each current value from 0 A to 300 A is within ±0.5% with respect to Sample No. 10, so the predetermined inductance characteristics can be sufficiently maintained. From this, the chamfer width F with respect to the width Ws1 of the front end face11 The ratio (F 11 / Ws1) is preferably 10% or more and 45% or less, and more preferably 20% or more. Further, considering not only the loss reduction effect but also the weight reduction effect, the ratio (F 11 / Ws1) is preferably more than 25%.

[0177] <Test Example 3> In Test Example 3, the chamfer width F of the first inner chamfered portion 41i 12 was changed, and the influence of the chamfer width F 12 on the electromagnetic performance was examined. Specifically, for the reactors of Sample Nos. 3-1 to 3-4 in which the chamfer width F 12 of the first inner chamfered portion 41i was set in the range of 0 mm to 2 mm, the same evaluation as in Test Example 1 was performed. Sample No. 3-1 is the same as Sample No. 1-1 in Test Example 1. The difference between Sample Nos. 3-1 to 3-4 is only the chamfer width F 12 of the first inner chamfered portion 41i.

[0178] For the reactors of each sample, the inductance and total loss were determined in the same manner as in Test Example 1. The results are shown in Table 3. In Table 3, the inductance at each current value in Sample Nos. 3-1 to 3-4 is shown as the ratio of the difference from the inductance at each current value in Sample No. 10. The total loss of Sample Nos. 3-1 to 3-4 is shown as the ratio of the difference from the total loss of Sample No. 10. Further, in the same manner as in Test Example 1, Table 3 shows the volume reduction amount and mass ratio of the first core in Sample Nos. 3-1 to 3-4 with respect to the first core in Sample No. 10.

[0179]

Table 3

[0180] As shown in Table 3, the chamfer width F of the first inner chamfered portion 12The smaller it is, the smaller the loss becomes, and it can be seen that it is easier to suppress the occurrence of loss. Samples No. 3-1 to No. 3-3 can reduce the loss by 0.5% or more compared to Sample No. 10. From this, the ratio (F 12 of the chamfer width F 12 to the width Ws1 of the tip surface) is considered preferably 12.5% or less, more preferably 10% or less.

[0181] <Test Example 4> In Test Example 4, the width Ws2 of the opposing surface 3bf was changed, and the influence of the reduction amount of the width Ws2 with respect to the width Ws1 of the tip surface 3af on the electromagnetic performance was examined. Specifically, for the reactors of Samples No. 4-1 to No. 4-5 in which the width Ws2 of the opposing surface 3bf was made shorter than the width Ws1 of the tip surface 3af in the range of 1 mm to 5 mm, the same evaluation as in Test Example 1 was performed. The difference between Samples No. 4-1 to No. 4-5 is only the width Ws2 of the opposing surface 3bf. Samples No. 4-1 to No. 4-5 are the same as Sample No. 1-1 of Test Example 1 except that the width Ws2 of the opposing surface 3bf is different.

[0182] The widths Ws2 of the opposing surfaces 3bf of Samples No. 4-1 to No. 4-5 are 11 mm, 10 mm, 9 mm, 8 mm, and 7 mm, respectively. That is, the widths W 32 of the second end core portions 32 of Samples No. 4-1 to No. 4-5 are 73 mm, 71 mm, 69 mm, 67 mm, and 65 mm, respectively. The difference (Ws1 - Ws2) between the width Ws1 and the width Ws2 and the ratio (Ws2 / Ws1) of the width Ws2 to the width Ws1 in each sample are shown in Table 4, respectively.

[0183] For the reactors of each sample, the inductance and the total loss were determined in the same manner as in Test Example 1. The results are shown in Table 4. In Table 4, the inductance at each current value in Samples No. 4-1 to No. 4-5 is shown as the ratio of the difference to the inductance at each current value in Sample No. 10. The total loss of Samples No. 4-1 to No. 4-5 is shown as the ratio of the difference to the total loss of Sample No. 10.

[0184] (Evaluation of Weight Reduction Effect) Furthermore, for the reactors of Sample Nos. 4-1 to 4-5, the weight reduction effect of the magnetic core was evaluated. Here, the reduction amount of the volume of the second core in Sample Nos. 4-1 to 4-5 with respect to the volume of the second core in Sample No. 10 was calculated. The volume reduction amount is obtained by subtracting the volume of the second core in Sample Nos. 4-1 to 4-5 from the volume of the second core in Sample No. 10. The results are shown in Table 4. Also, the mass ratio of the second core in Sample Nos. 4-1 to 4-5 to the second core in Sample No. 10 was calculated. The mass ratio is expressed as a percentage of the mass of the second core in Sample Nos. 4-1 to 4-5 with respect to the mass of the second core in Sample No. 10. Table 4 also shows the mass ratio.

[0185]

Table 4

[0186] As shown in Table 4, the shorter the width Ws2 of the opposing surface is than the width Ws1 of the front end surface, that is, the larger the difference (Ws1 - Ws2) between the width Ws1 of the front end surface and the width Ws2 of the opposing surface is, the larger the volume reduction amount of the second core becomes. That is, the weight reduction effect becomes larger. However, when the width Ws2 of the opposing surface becomes shorter, the deterioration of the inductance characteristics becomes more prominent accordingly. Specifically, the variation becomes larger with respect to the inductance at each current value from 0 A to 300 A in Sample No. 10. That is, it becomes difficult to maintain the same inductance characteristics as in Sample No. 10. Table 4As can be seen, when the width Ws2 of the opposing surface is decreased, the volume reduction amount of the second core increases at a constant rate, while the variation range of the inductance is larger than the increasing rate of the volume reduction amount. Since the variation range of the inductance at each current value from 0 A to 300 A for Samples No. 4-1 to No. 4-4 is within ±2.5% with respect to Sample No. 10, it can be said that the predetermined inductance characteristics are generally maintained. In particular, since the variation range of the inductance for Samples No. 4-1 to No. 4-3 with respect to Sample No. 10 is within ±1.5%, the predetermined inductance characteristics can be maintained better. From this, it is considered that the ratio (Ws2 / Ws1) of the width Ws2 of the opposing surface to the width Ws1 of the front end surface is preferably 60% or more, and more preferably 70% or more. Further, considering the loss reduction effect and the weight reduction effect, the ratio (Ws2 / Ws1) is preferably 92% or less, and more preferably 90% or less.

[0187] <Test Example 5> Regarding the reactor having the same configuration as that of the above-described Embodiment 3, the influence on the electromagnetic performance was evaluated. The samples of the reactor used in Test Example 5 have an E-E type magnetic core 3. The relative permeability μr1 of the first core 3a is 20. The relative permeability μr2 of the second core 3b is 150.

[0188] In Test Example 5, evaluations were performed on Samples No. 5-1 to No. 5-3 in which the front end surface 3af has only the first outer chamfered portion 41o and Sample No. 50 in which the front end surface 3af has the first outer chamfered portion 41o and the first inner chamfered portion 41i. For Samples No. 5-1 to No. 5-3, the chamfer width F 11 of the first outer chamfered portion 41o was set in the range of 5 mm to 6 mm. The difference between Samples No. 5-1 to No. 5-3 is only the chamfer width F 11 of the first outer chamfered portion 41o. The sizes of the magnetic core 3 and each main part are shown below.

[0189] (Sizes of Magnetic Core and Main Parts) · Length L of magnetic core 3: 70 mm · Width W of magnetic core 3: 75 mm · Height H of the magnetic core 3: 30 mm · Width of the middle core portion 30 = width of the first middle core portion 30a and the second middle core portion 30b: 24 mm · Lengths of the first end core portion 31 and the second end core portion 32: 12.5 mm · Width W of the first end core portion 31 and the second end core portion 32 31 , W 32 : 75 mm · Width of the first part 33a, 34a of the first side core portion 33 and the second side core portion 34 = width Ws1 of the front end face 3af: 12 mm · Width of the second part 33b, 34b of the first side core portion 33 and the second side core portion 34 = width Ws2 of the opposing face 3bf: 12 mm

[0190] For Samples No. 5 - 1 to No. 5 - 3, the chamfer width F of the first outer chamfered portion 41o 11 is larger than the chamfer width F of the first inner chamfered portion 41i 12 In Samples No. 5 - 1 to No. 5 - 3, the chamfer width F of the first inner chamfered portion 41i 12 is 0 mm for all. For Sample No. 50, the chamfer width F of the first outer chamfered portion 41o 11 and the chamfer width F of the first inner chamfered portion 41i 12 are the same, which is a comparison model. In Sample No. 50, the chamfer widths F of the first outer chamfered portion 41o and the first inner chamfered portion 41i 11 , F 12 are 2.25 mm.

[0191] Regarding the reactors of each sample, the inductance and total loss were obtained in the same manner as in Test Example 1. The results are shown in Table 5. In Table 5, the inductance at each current value for Samples No. 5 - 1 to No. 5 - 3 is shown as the ratio of the difference to the inductance at each current value for Sample No. 50. The total loss of Samples No. 5 - 1 to No. 5 - 3 is shown as the ratio of the difference to the total loss of Sample No. 50. Furthermore, Table 5 shows the volume reduction amount and mass ratio of the first core in Samples No. 5 - 1 to No. 5 - 3 with respect to the first core in Sample No. 50.

[0192]

Table 5

[0193] As shown in Table 5, even when the magnetic core is of the E-E type, similar to the case of the E-T type in Test Example 2 described above, the chamfer width F of the first outer chamfered portion 11 the larger it is, the smaller the loss becomes. That is, the loss reduction effect becomes larger. Also, the larger the chamfer width F 11 is, the larger the volume reduction amount of the first core becomes. That is, the weight reduction effect becomes larger. However, if the chamfer width F 11 is made too large, the inductance characteristics tend to deteriorate. Specifically, the variation in inductance at each current value from 0 A to 300 A in Sample No. 50 becomes larger. That is, it becomes difficult to maintain the same inductance characteristics as Sample No. 50 . Samples No. 5-1 and No. 5-2 can sufficiently maintain the predetermined inductance characteristics because the variation range of inductance at each current value from 0 A to 300 A with respect to Sample No. 50 is within ±0.5%. From this, in the E-E type magnetic core, the ratio (F 11 / Ws1) of the chamfer width F 11 to the width Ws1 of the front end face is considered to be preferably 40% or more and 45% or less.

Explanation of Signs

[0194] 1 Reactor 2 Coil 2a First end face, 2b Second end face 21 Winding portion, 21a, 21b End portions 3 Magnetic core 3a First core, 3b Second core 30 Middle core portion 30a First middle core portion, 30b Second middle core portion 31 First end core portion, 32 Second end core portion 33 First side core portion, 34 Second side core portion 33a, 34a First portions, 33b, 34b Second portions 3af front end face, 3bf opposing face 3ao, 3bo outer edges 3ai, 3bi inner edges 41 first chamfering portion 41o first outer chamfering portion, 41i first inner chamfering portion 42 second chamfering portion 42o second outer chamfering portion, 42i second inner chamfering portion F 11 ,F 12 ,F 21 ,F 22 chamfering width W, Ws1, Ws2, W 31 ,W 32 width L length H height 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 machine power supply 1200 vehicle 1210 main battery 1220 motor 1230 sub - battery 1240 auxiliary machines 1250 wheel 1300 engine

Claims

1. A reactor comprising a coil and a magnetic core, wherein the magnetic core includes a first core and a second core configured in a θ shape by being combined in the X direction, the first core includes a first end core portion, at least a part of a middle core portion, and at least a part of both side core portions including a first side core portion and a second side core portion, the second core includes a second end core portion, the remaining part of the middle core portion, and the remaining parts of the first side core portion and the second side core portion respectively, the first end core portion faces a first end face of the coil, the second end core portion faces a second end face of the coil, the middle core portion is disposed inside the coil, the first side core portion and the second side core portion are disposed outside the coil so as to sandwich the middle core portion, each of the first side core portion and the second side core portion of the first core has a tip face facing the second core, the surface of the second core has a facing face facing the tip face, when the magnetic core is viewed from the Z direction, the outer edge of the facing face is located inside in the Y direction from the outer edge of the tip face, and the inner edge of the facing face and the inner edge of the tip face are substantially aligned in the Y direction, the tip face has a first chamfered portion along the Z direction, the first chamfered portion includes at least the first outer chamfered portion connected to the outer edge of the tip face and the first inner chamfered portion connected to the inner edge of the tip face, the chamfering width of the first outer chamfered portion is larger than the chamfering width of the first inner chamfered portion, the width in the Y direction of the facing face is shorter than the width in the Y direction of the tip face, the X direction is a direction along the axial direction of the middle core portion, the Y direction is a direction in which the middle core portion, the first side core portion, and the second side core portion are arranged in parallel, the Z direction is a direction perpendicular to both the X direction and the Y direction, a reactor.

2. The reactor according to claim 1, wherein the chamfering width of the first outer chamfered portion is 10% or more and 45% or less of the width in the Y direction of the tip face.

3. The reactor according to claim 1 or claim 2, wherein the chamfering width of the first inner chamfered portion is 12.5% or less of the width in the Y direction of the tip face.

4. The reactor according to any one of claims 1 to 3, wherein the chamfering width of the first inner chamfering portion is 2 mm or less.

5. The reactor according to any one of claims 1 to 4, wherein the first outer chamfering portion is a round chamfering.

6. The first core is a molded body of a composite material in which soft magnetic powder is dispersed in resin, The reactor according to any one of claims 1 to 5, wherein the second core is a compacted molded body of raw material powder containing soft magnetic powder.

7. The reactor according to any one of claims 1 to 6, wherein the relative permeability of the first core is 5 or more and 50 or less.

8. The reactor according to any one of claims 1 to 7, wherein the relative permeability of the second core is 50 or more and 500 or less.

9. The reactor according to any one of claims 1 to 8, wherein the relative permeability of the second core is higher than that of the first core.

10. The reactor according to any one of claims 1 to 9, wherein the width in the Y direction of the opposing surface is 60% or more and 92% or less of the width in the Y direction of the tip surface.

11. The opposing surface has a second chamfering portion along the Z direction, The second chamfering portion includes at least the second outer chamfering portion that connects to the outer edge of the opposing surface and the second inner chamfering portion that connects to the inner edge of the opposing surface, The reactor according to any one of claims 1 to 10, wherein the chamfering width of the second outer chamfering portion is larger than the chamfering width of the second inner chamfering portion.

12. The first core includes all of each of the first side core portions and the second side core portions, The reactor according to any one of claims 1 to 11, wherein the opposing surface is provided in the second end core portion of the second core.

13. The first core includes a part of each of the first side core portions and the second side core portions, The reactor according to any one of claims 1 to 11, wherein the opposing surface is provided in the remaining portions of each of the first side core portions and the second side core portions of the second core.

14. A converter comprising the reactor according to any one of claims 1 to 13, Converter.

15. A power conversion device comprising the converter according to claim 14. Power conversion device.

Images