Reactor

Abstract

To provide a reactor having relatively large inductance, comprising a coil partially embedded into a holding member.SOLUTION: A reactor 10 comprises: a coil 20 having a winding part 22; a holding member 40; and a magnetic core 60. The winding part 22 is partially embedded into an inner part of the holding member 40, and includes: an upper side exposed part 32 and a lower side exposed part, exposed from the holding member 40 in a vertical direction (a Z direction). The upper side exposed part 32 includes an upper side curve surface part 324. The upper side curve surface part 324 is exposed from the holding member 40 on both sides of a lateral direction (a Y direction). The magnetic core 60 includes two outer legs 66. The winding part 22 is positioned between the two outer legs 66 in the lateral direction. The holding member 40 includes two side walls 44 which are corresponded to each of the outer legs 66. Each of the side wall 44 is positioned between the corresponded outer leg 66 and the winding part 22 in the lateral direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a reactor having a coil partially embedded inside a holding member. [Background technology]

[0002] This type of reactor is disclosed in, for example, Patent Document 1.

[0003] Patent Document 1 discloses a reactor including a coil, an integrated resin (holding member), and a magnetic core. The coil is partially embedded inside the holding member, and is thereby held by the holding member. The coil is a so-called glasses coil. More specifically, the coil has two winding parts connected to each other. Each of the winding parts is wound around a through hole (center hole) and is partially embedded inside the holding member. The two center holes of the coil extend parallel to each other. The magnetic core has a single ring shape and passes through the two center holes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6593780 Summary of the Invention [Problem to be solved by the invention]

[0005] By partially embedding the winding part of the coil inside the holding member as in Patent Document 1, it is possible to prevent the turns of the winding part from coming apart. On the other hand, the magnetic core in Patent Document 1 has a UU core-like shape as a whole. When a reactor is formed from a pair of glasses coils and a UU core-shaped magnetic core, the magnetic path length tends to be long and the cross-sectional area of ​​the magnetic path tends to be small. In other words, with the structure in Patent Document 1, it is difficult to increase the inductance.

[0006] SUMMARY OF THE PRESENT DISCLOSURE In view of the above, an object of the present invention is to provide a reactor including a coil partially embedded inside a holding member, the reactor having a relatively large inductance. [Means for solving the problem]

[0007] The inductance of the reactor should be increased by using a coil having a single winding portion and a magnetic core shaped like an EE core. More specifically, the coil of this reactor has a single central hole extending along the front-rear direction. The winding portion of the coil is wound around the central hole. The magnetic core has a middle leg and two outer parts. The middle leg passes through the central hole of the coil. The two outer parts sandwich the winding portion in the lateral direction perpendicular to the front-rear direction and are connected to the middle leg. That is, the magnetic core has a shape like an EE core in the horizontal plane defined by the front-rear direction and the lateral direction. With this structure, the magnetic path length can be shortened and the cross-sectional area of ​​the magnetic path can be increased. That is, the inductance of the reactor can be increased.

[0008] A reactor having the above-mentioned structure seems to be easy to form. However, in this reactor, the outer part of the magnetic core is arranged so as to face the side of the winding part in the horizontal direction. If the side of the winding part is exposed toward the outer part of the magnetic core, there is a risk that the insulation between the side of the winding part and the outer part of the magnetic core will be reduced if the side of the winding part is damaged. Therefore, the holding member needs to completely cover and insulate between the side of the winding part and the outer part of the magnetic core. That is, the holding member needs to be molded so that the side of the winding part is embedded in the holding member.

[0009] On the other hand, when molding the holding member in this manner, it is necessary to hold the coil so that it does not move in the horizontal plane as well as in the vertical direction. More specifically, it is necessary to hold the side of the winding part by pressing it down with a mold. As a result of holding it with a mold, a mark of the mold is inevitably formed on the side of the holding member in which the coil is embedded. More specifically, a portion is formed on the side of the holding member where the side of the winding part is exposed toward the outer part of the magnetic core.

[0010] As can be understood from the above description, it is difficult to provide a magnetic core shaped like an EE core in a reactor having a coil partially embedded inside a holding member. The inventors of the present invention conducted extensive research to solve this problem, and as a result, invented a new structure for a holding member with an embedded coil. With this new structure, a magnetic core shaped like an EE core can be provided in a reactor having a coil partially embedded inside a holding member. Specifically, the present invention provides the following reactor.

[0011] The present invention provides a first reactor, A reactor including a coil, a holding member, and a magnetic core, The coil has a winding portion, The winding portion is wound around a single central axis extending along a front-rear direction, The winding portion has an upper exposed portion and a lower exposed portion, the upper exposed portion and the lower exposed portion are located on opposite sides of the winding portion in a vertical direction perpendicular to the front-rear direction, the winding portion is partially embedded within the holding member, each of the upper exposed portion and the lower exposed portion is exposed from the holding member in the up-down direction; The upper exposed portion has an upper curved surface portion, The upper curved surface portion is exposed from the holding member on both sides in a lateral direction perpendicular to both the front-rear direction and the up-down direction, The magnetic core has a center leg and two outer legs, Each of the outer parts has an outer leg and two connecting parts, The middle leg is surrounded by the winding portion in a vertical plane perpendicular to the front-rear direction, The winding portion is located between the two outer legs in the lateral direction, In each of the outer parts, the connecting portion connects both ends of the outer leg in the front-rear direction to both ends of the middle leg in the front-rear direction, The holding member has two side walls respectively corresponding to the outer legs, Each of the side walls is located between the corresponding outer leg and the winding portion in the lateral direction. Provide a reactor.

[0012] Further, the present invention provides a first reactor as the second reactor, The magnetic core is a gapless core and is at least partially made of a composite magnetic material; The composite magnetic body includes a binder and a magnetic powder dispersed in the binder. Provide a reactor.

[0013] Further, the present invention provides a third reactor, which is a second reactor, The magnetic core is made of only the composite magnetic body. Provide a reactor.

[0014] Further, the present invention provides a fourth reactor, which is any one of the first to third reactors, Each of the side walls does not have a hole that opens toward both the winding portion and the outer leg. Provide a reactor.

[0015] Further, the present invention provides a fifth reactor, which is any one of the first to fourth reactors, The lower exposed portion has a lower curved surface portion, The lower curved surface portion is exposed from the holding member on both sides in the lateral direction. Provide a reactor.

[0016] Further, the present invention provides a sixth reactor, which is the fifth reactor, The upper exposed portion has an upper flat portion and two of the upper curved portions, the upper curved surface portions are located on opposite sides of the upper flat surface portions in the lateral direction, The lower exposed portion has a lower flat portion and two of the lower curved portions, The lower curved surface portions are located on opposite sides of the lower flat surface portions in the lateral direction. Provide a reactor.

[0017] Further, the present invention provides a seventh reactor, which is any one of the first to sixth reactors, The magnetic core is located between the upper exposed portion and the lower exposed portion in the vertical direction. Provide a reactor.

[0018] Further, the present invention provides an eighth reactor, which is any one of the first to seventh reactors, The holding member has a lower support portion, a front upper support portion, and a rear upper support portion, The lower support portion supports a lower surface of the magnetic core, the front upper support portion is located in front of the winding portion and in contact with an upper surface of the magnetic core, The rear upper support portion is located behind the winding portion and is in contact with the upper surface of the magnetic core. Provide a reactor.

[0019] Further, the present invention provides a ninth reactor, which is the eighth reactor, the holding member is provided with a fastening portion for fastening the reactor to an object, The lower support portion is integrally formed with the holding member, The fastener is attached to the lower support. Provide a reactor.

[0020] Further, the present invention provides a tenth reactor, which is the ninth reactor, The lower surface of the fastening portion is flush with the bottom surface of the winding portion. Provide a reactor.

[0021] Further, the present invention provides an eleventh reactor, which is any one of the first to tenth reactors, The holding member has an outer wall portion, The outer wall portion is in contact with an outer peripheral surface of the magnetic core in a horizontal plane perpendicular to the up-down direction. Provide a reactor.

[0022] Further, the present invention provides a twelfth reactor, which is any one of the first to eleventh reactors, The magnetic powder of the composite magnetic body has a composition formula of Fe X1 B X2 S X3 P X4 C X5 Cu X6 Cr X7 X1+X2+X3+X4+X5+X6+X7=100at%, 79≦X1≦86at%, 4≦X2≦13at%, 0≦X3≦8at%, 1≦X4≦14at%, 0≦X5≦5at%, 0.4≦X6≦1.4at%, 0≦X7≦3at%. Provide a reactor.

[0023] Further, the present invention provides a thirteenth reactor, which is the twelfth reactor, The magnetic powder is an alloy powder in which a part of Fe is replaced with one or more elements selected from Co, Ni, V, Nb, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Zn, Ti, Al, Mn, S, O, N, Y, and rare earth elements, and the one or more elements selected from Co, Ni, V, Nb, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Zn, Ti, Al, Mn, S, O, N, Y, and rare earth elements are 3 at% or less of the entire composition, and the sum of the one or more elements selected from Co, Ni, V, Nb, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Zn, Ti, Al, Mn, S, O, N, Y, and rare earth elements and Fe is X1 at%. Provide a reactor.

[0024] Further, the present invention provides a 14th reactor, which is the 12th or 13th reactor, The alloy powder contains nanocrystals of α-Fe, The average particle size (D50) of the nanocrystals is 5 nm or more and 50 nm or less. Provide a reactor.

[0025] Further, the present invention provides a fifteenth reactor, which is any one of the first to fourteenth reactors, The reactor has a shape that is rotationally symmetrical about 180 degrees when viewed from above along the vertical direction. Provide a reactor.

[0026] Furthermore, the present invention provides a 16th reactor, The coil has a winding portion, The winding portion is wound around a single central axis extending along a front-rear direction, the winding portion is partially embedded within the holding member, The magnetic core is a gapless core, The magnetic core has a center leg and two outer legs, Each of the outer parts has an outer leg and two connecting parts, The middle leg is surrounded by the winding portion in a vertical plane perpendicular to the front-rear direction, The winding portion is located between the two outer legs in a lateral direction perpendicular to the front-rear direction, In each of the outer parts, the connecting portion connects both ends of the outer leg in the front-rear direction to both ends of the middle leg in the front-rear direction, The retaining member has a front upper support portion, a rear upper support portion, and an outer wall portion, the front upper support portion is located in front of the winding portion and is in contact with an upper surface of the magnetic core in a vertical direction perpendicular to both the front-rear direction and the lateral direction, the rear upper support portion is located rearward of the winding portion and in contact with an upper surface of the magnetic core, the outer wall portion is in contact with an outer circumferential surface of the magnetic core in a horizontal plane perpendicular to the up-down direction, the holding member is provided with a fastening portion for fastening the reactor to an object, The fastening portion is integrally formed with the holding member. Provide a reactor. Effect of the Invention

[0027] According to the present invention, the upper exposed portion of the winding portion is exposed upward from the holding member, and the lower exposed portion of the winding portion is exposed downward from the holding member. As can be seen from this structure, when molding the holding member, the upper exposed portion and the lower exposed portion can be sandwiched vertically by a mold. Furthermore, the upper curved portion is exposed outward in the lateral direction. As can be seen from this structure, when molding the holding member, the upper curved portion can be sandwiched horizontally by a mold, thereby holding it so as not to move in the horizontal plane. That is, the holding member of the present invention can be formed so that the winding portion is partially embedded.

[0028] According to the invention, the side walls of the holding member are located laterally between the windings and the outer legs, respectively, and insulate the windings from the magnetic core, so that a reactor with a coil partially embedded inside the holding member can be provided with a magnetic core shaped like an EE core.

[0029] As described above, the reactor of the present invention can be fabricated using a coil having a single winding and a magnetic core shaped like an EE core. That is, the present invention provides a reactor having a coil partially embedded inside a holding member and having a relatively large inductance. [Brief description of the drawings]

[0030] [Figure 1] 1 is a perspective view showing a reactor according to an embodiment of the present invention together with a bus bar, and a nut is attached to the reactor. [Diagram 2] FIG. 2 is a top view showing the reactor of FIG. [Diagram 3] 2 is a bottom view of the reactor of FIG 1, with the outline of the hidden magnetic core drawn in dashed lines. [Figure 4] FIG. 2 is a side view showing the reactor of FIG. [Diagram 5] 2 is a front view showing the reactor of FIG 1. A part of the hidden outline of a winding part of the coil and a part of the hidden outline of a holding member are drawn by dashed lines. [Figure 6] 2 is a perspective view showing an intermediate structure before a magnetic core is formed in the reactor of FIG. 1. A nut is not attached to the intermediate structure. The imaginary central axis of the winding part of the coil of the intermediate structure is drawn by a dashed line. [Figure 7] 7 is a top view showing the intermediate structure of Fig. 6. The outline of the outer periphery of the magnetic core when the magnetic core is formed is drawn by a dashed line. [Figure 8] 7 is a bottom view showing the intermediate structure of Fig. 6. The outline of the hidden magnetic core when the magnetic core is formed is drawn by a dashed line. [Figure 9]7 is a side view of the intermediate structure of FIG. 6, with a part of the hidden outline of the coil drawn in dashed lines. [Figure 10] 7 is a front view of the intermediate structure of FIG. 6, with the hidden outline of the turns of the winding portion drawn in dashed lines. [Figure 11] 7 is a perspective view showing a coil of the intermediate structure of Fig. 6. The imaginary central axis of the winding part is drawn by a dashed line. [Figure 12] 2 is a perspective view showing a magnetic core of the reactor in FIG 1. A part of the magnetic core is enlarged to show a schematic diagram of the structure of a composite magnetic body. [Figure 13] 13 is a top view of the magnetic core of FIG. 12, with imaginary boundaries between portions of the magnetic core drawn with dashed lines. [Figure 14] 2 is a side view showing a modified example of the reactor of FIG 1. A part of the hidden outline of the winding part of the coil is drawn by a dashed line. [Figure 15] 15 is a front view showing the reactor of FIG 14. A part of the hidden outline of the winding part of the coil is drawn by a dashed line. [Figure 16] 1. FIG. 4 is a perspective view showing another modified example of the reactor in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] 1, a reactor 10 according to an embodiment of the present invention is a single-phase reactor of a boost device (not shown). The reactor 10 is used, for example, to boost a current supplied to a motor (not shown) of an EV (Electric Vehicle). That is, the reactor 10 is placed in a relatively small space and used in a high vibration environment. However, the present invention is not limited thereto and can be applied to various reactors.

[0032] The reactor 10 of this embodiment includes a coil 20, a holding member 40 made of an insulator to which four fastening parts 50 made of an insulator are attached, and a magnetic core 60 made of a soft magnetic material. In particular, the reactor 10 of this embodiment includes only the above-mentioned components (the coil 20, the holding member 40, the fastening parts 50, and the magnetic core 60). However, the present invention is not limited to this. For example, the reactor 10 may further include a case (not shown) that houses the above-mentioned components.

[0033] 6, the coil 20 forms the intermediate structure 12 together with the holding member 40 to which the fastening portion 50 is attached. In the intermediate structure 12, the coil 20 is held by the holding member 40. More specifically, the holding member 40 is molded so as to cover most of the coil 20. The coil 20 is partially embedded inside the holding member 40, whereby the holding member 40 holds the coil 20.

[0034] 1 together with FIG. 6, the magnetic core 60 is fixed to the intermediate structure 12. The magnetic core 60 forms the reactor 10 together with the intermediate structure 12. The intermediate structure 12 has the same structure as the reactor 10 except that it does not include the magnetic core 60. That is, the coil 20, the holding member 40, and the fastening portion 50 of the intermediate structure 12 have the same structures as the coil 20, the holding member 40, and the fastening portion 50 of the reactor 10, respectively.

[0035] The coil 20 of this embodiment will be described below.

[0036] Referring to FIG. 11, the coil 20 of this embodiment is formed by winding a coated electric wire. The coated electric wire is formed by covering a conductor made of metal with a thin insulating film made of an insulator. The coil 20 has a winding part 22 and two terminals 28. The winding part 22 is wound around a single central axis AX extending along the front-rear direction (X direction). The winding part 22 is an assembly of a plurality of turns 22T each of which winds around the central axis AX approximately once. The two terminals 28 are connected to the turns 22T at both ends of the winding part 22 in the X direction, with the conductor exposed at the tip.

[0037] The winding portion 22 of this embodiment is formed by edgewise winding a rectangular coated electric wire. The winding portion 22 is wound so that the turns 22T are in close contact with each other in the X direction. That is, the winding portion 22 of this embodiment has a solenoid shape. By forming the winding portion 22 in this manner, the number of turns of the winding portion 22 (i.e., the number of turns 22T) can be increased while increasing the cross-sectional area of ​​the turn 22T in a plane including the central axis AX, thereby obtaining a reactor 10 suitable for large currents. However, the present invention is not limited to this. For example, the winding portion 22 may be wound sparsely so that the turns 22T are separated from each other in the X direction. The winding portion 22 may also be formed by winding a round wire.

[0038] A central hole 24 is formed in the winding portion 22. The central hole 24 is a space surrounded by the winding portion 22 in a vertical plane (YZ plane) perpendicular to the X direction. The central hole 24 is open on both sides in the X direction. In this embodiment, the central hole 24 is completely surrounded by the solenoid-shaped winding portion 22 in the YZ plane. More specifically, the winding portion 22 has an inner peripheral surface 222 and an outer peripheral surface 224 in the YZ plane. The inner peripheral surface 222 faces the central hole 24 in the YZ plane. The outer peripheral surface 224 defines the outer periphery of the winding portion 22 in the YZ plane.

[0039] The winding part 22 has a bottom surface 22L. The bottom surface 22L is a part of the outer peripheral surface 224, and is located at the lower end (the end on the -Z side) of the winding part 22 in the up-down direction (Z direction) perpendicular to the X direction. The winding part 22 of this embodiment has a rounded rectangular shape in the YZ plane, and thus the bottom surface 22L extends along a horizontal plane (XY plane) perpendicular to the Z direction. The winding part 22 of this embodiment has the shape described above. However, the shape of the winding part 22 of the present invention is not limited to this embodiment. For example, the winding part 22 may have a track shape in the YZ plane.

[0040] As shown in FIG. 11, one of the two terminals 28 in this embodiment is connected to the turn 22T located at the front end (end on the +X side) of the winding portion 22 and extends forward (in the +X direction). The other of the two terminals 28 in this embodiment is connected to the turn 22T located at the rear end (end on the -X side) of the winding portion 22 and extends backward (in the -X direction). Each of the terminals 28 in this embodiment is a part of a single coil 20 and is an integral member with the winding portion 22. However, the present invention is not limited to this. For example, each of the terminals 28 may be a separate member from the winding portion 22, and may be connected to the winding portion 22 by welding or the like.

[0041] As can be seen from Figures 6 to 10, the winding portion 22 is partially embedded inside the holding member 40. In particular, with reference to Figure 10, an inner circumferential surface 222 of the winding portion 22 is completely covered by the holding member 40. With reference to Figures 6 and 10, most of an outer circumferential surface 224 of the winding portion 22 is covered by the holding member 40. With reference to Figures 9 and 10, most of the front surface (the surface on the +X side) and rear surface (the surface on the -X side) of the winding portion 22 are also covered by the holding member 40.

[0042] 9, the connection portion of each of the terminals 28 with the turn 22T is covered by the holding member 40. Meanwhile, the tip of each of the terminals 28 is exposed from the holding member 40. That is, each of the terminals 28 is drawn out from the winding portion 22 to the outside of the holding member 40, and extends away from each other along the X direction. However, in the present invention, the portion of the winding portion 22 from which the terminals 28 are drawn out and the shape of each of the terminals 28 are not particularly limited. For example, each of the terminals 28 may be drawn out from the upper surface of the winding portion 22 and extend upward.

[0043] As described above, most of the winding portion 22 in this embodiment is embedded inside the holding member 40. This structure can prevent the turns 22T of the winding portion 22 from coming apart. Meanwhile, the winding portion 22 has an upper exposed portion 32 and a lower exposed portion 34. The upper exposed portion 32 and the lower exposed portion 34 are traces of a mold (not shown) used when molding the holding member 40. The upper exposed portion 32 and the lower exposed portion 34 are located on opposite sides of the winding portion 22 in the Z direction. The upper exposed portion 32 is exposed upward (+Z direction) from the holding member 40, and the lower exposed portion 34 is exposed downward (-Z direction) from the holding member 40. That is, each of the upper exposed portion 32 and the lower exposed portion 34 is exposed from the holding member 40 in the Z direction.

[0044] 6, 7, 9, and 10, the upper exposed portion 32 of this embodiment has one upper flat portion 322 and two upper curved portion 324. The upper flat portion 322 and the upper curved portion 324 are each part of the outer circumferential surface 224 of the winding portion 22. In particular, the upper flat portion 322 and the upper curved portion 324 are the upper surface (the surface on the +Z side) of the upper exposed portion 32. That is, the upper flat portion 322 and the upper curved portion 324 are each part of the upper surface of the winding portion 22.

[0045] The upper flat portion 322 extends along the XY plane. The upper curved surface portions 324 are located on opposite sides of the upper flat portion 322 in a lateral direction (Y direction) perpendicular to both the X and Z directions. More specifically, the upper curved surface portions 324 are connected to both edges of the upper flat portion 322 in the Y direction. Each of the upper curved surface portions 324 extends outward and downward in the Y direction while drawing an arc. That is, each of the upper curved surface portions 324 has an arc shape in the YZ plane and is exposed outward in the Y direction from the holding member 40.

[0046] 8 to 10, the lower exposed portion 34 of this embodiment has one lower flat portion 342 and two lower curved portion 344. Each of the lower flat portion 342 and the lower curved portion 344 is part of the outer circumferential surface 224 of the winding portion 22. More specifically, the lower flat portion 342 and the lower curved portion 344 are the lower surface (the surface on the -Z side) of the lower exposed portion 34. That is, each of the lower flat portion 342 and the lower curved portion 344 is part of the lower surface of the winding portion 22.

[0047] The lower flat portion 342 in this embodiment is the bottom surface 22L of the winding portion 22, and extends along the XY plane. The lower curved surface portions 344 are located on opposite sides of the lower flat portion 342 in the Y direction. More specifically, the lower curved surface portions 344 are connected to both edges of the lower flat portion 342 in the Y direction. Each of the lower curved surface portions 344 extends outward and upward in the Y direction while drawing an arc. That is, each of the lower curved surface portions 344 has an arc shape in the YZ plane, and is exposed from the holding member 40 to the outside in the Y direction.

[0048] Referring to FIG. 1, a portion of the retaining member 40 and the magnetic core 60 of the present embodiment will be described below, along with a method of forming the retaining member 40 of the present embodiment.

[0049] 6 and 7, the holding member 40 of this embodiment has two side walls 44. With reference to Fig. 6 and 10, each of the side walls 44 has a flat plate shape extending parallel to the XZ plane. The side walls 44 are separated from each other in the Y direction and extend parallel to each other along the XZ plane.

[0050] Referring to FIG. 12, the magnetic core 60 of this embodiment is a gapless core made of only the composite magnetic body 60M. That is, the magnetic core 60 extends continuously without a break in the XY plane. The composite magnetic body 60M includes a binder 60B made of an insulating material such as a thermosetting resin, and magnetic powder 60P dispersed in the binder 60B. The magnetic powder 60P is made of a soft magnetic material, bound to each other by the binder 60B, and insulated from each other. The composite magnetic body 60M may include other materials such as a non-magnetic filler in addition to the binder 60B and the magnetic powder 60P. A gapless core made of such a composite magnetic body 60M is difficult to break and is suitable for the reactor 10 (see FIG. 1) used in a high vibration environment.

[0051] 12 and 13, the magnetic core 60 has a middle leg 62 and two outer parts 64. Each of the outer parts 64 has an outer leg 66 and two connecting parts 68. In each of the outer parts 64, the connecting parts 68 connect both ends of the outer leg 66 in the X direction to both ends of the middle leg 62 in the X direction. In this embodiment, these parts are continuous with each other without any gaps. In addition, the magnetic core 60 has an upper surface 60U, a lower surface 60L, and an outer peripheral surface 60E. Each of the upper surface 60U and the lower surface 60L in this embodiment is a smooth plane parallel to the XY plane and extends continuously over all parts of the magnetic core 60. The outer peripheral surface 60E defines the outer periphery of the magnetic core 60 in the XY plane. In this embodiment, the outer peripheral surface 60E is a closed curved surface extending parallel to the Z direction.

[0052] 3 together with FIG. 6, the middle leg 62 of the magnetic core 60 is located inside the central hole 24. That is, the middle leg 62 of the magnetic core 60 is surrounded by the winding portion 22 in the YZ plane. The winding portion 22 is located between the two outer legs 66 in the Y direction. In addition, the two side walls 44 of the holding member 40 are provided corresponding to the outer legs 66, respectively. That is, the holding member 40 has two side walls 44 corresponding to the outer legs 66, respectively. Each of the side walls 44 is located between the corresponding outer leg 66 and the winding portion 22 in the Y direction.

[0053] 12, the magnetic core 60 of this embodiment has the above-mentioned structure, and thus has a shape like an EE core in the XY plane. The magnetic core 60 of this embodiment has a shape that is mirror-symmetrical with respect to the XY plane. However, the present invention is not limited to this, and the structure of the magnetic core 60 can be modified in various ways as long as the magnetic core 60 has a shape like an EE core in the XY plane. For example, each of the upper surface 60U and the lower surface 60L may have unevenness.

[0054] 1 together with FIG. 6, the reactor 10 of this embodiment is fabricated by forming a magnetic core 60 shaped like an EE core around the side wall 44 of the holding member 40. That is, the reactor 10 of this embodiment includes a coil 20 having a single winding portion 22, and a magnetic core 60 shaped like an EE core. With this structure, the magnetic path length can be shortened and the cross-sectional area of ​​the magnetic path can be increased compared to a conventional reactor consisting of a so-called eyeglass coil and a magnetic core shaped like a UU core. That is, the inductance of the reactor 10 can be increased compared to the prior art.

[0055] However, according to such a reactor 10, no matter how the magnetic core 60 is formed, the outer portion 64 of the formed magnetic core 60 is disposed so as to face the side surface of the winding portion 22 in the Y direction. If the side surface of the winding portion 22 is exposed toward the outer portion 64 of the magnetic core 60, for example, if an insulating coating (not shown) on the side surface of the winding portion 22 is damaged, the side surface of the winding portion 22 and Magnetic Core 60There is a risk that the insulation between the outer portion 64 and the inner portion 65 will decrease.

[0056] Therefore, the holding member 40 needs to completely cover the gap between the side of the winding portion 22 and the magnetic core 60 to provide insulation. That is, the holding member 40 needs to be molded so that the side of the winding portion 22 is embedded in the holding member 40. On the other hand, when the holding member 40 is molded in this manner, the coil 20 needs to be held so as not to move in the XY plane in addition to the Z direction. More specifically, the side of the winding portion 22 needs to be pressed down and held by a mold (not shown). As a result of holding by the mold, a mark of the mold is inevitably formed on the side wall 44 of the holding member 40 in which the coil 20 is embedded. More specifically, a portion is formed on the side wall 44 of the holding member 40 where the side of the winding portion 22 is exposed toward the magnetic core 60.

[0057] As can be understood from the above description, it is difficult to provide a magnetic core 60 shaped like an EE core in a reactor 10 including a coil 20 partially embedded inside a holding member 40. On the other hand, according to the present embodiment, the holding member 40 with the coil 20 embedded therein has a new structure not previously available. With this new structure, as described below, the holding member 40 can be molded from a thermosetting material such as resin so that the winding portion 22 of the coil 20 is completely embedded inside the holding member 40, except for the upper exposed portion 32 and the lower exposed portion 34.

[0058] 9 and 10, when forming the holding member 40, first, the coil 20 (see FIG. 11) is produced. Next, the winding portion 22 is placed inside a metal mold (not shown), and the upper exposed portion 32 and the lower exposed portion 34 of the coil 20 are sandwiched vertically by the metal mold. For example, the lower exposed portion 34 is placed on a lower metal mold (not shown). Next, the upper exposed portion 32 is pressed downward by an upper metal mold (not shown), thereby pressing the lower exposed portion 34 against the lower metal mold. At this time, the upper curved surface portion 324 is sandwiched by the upper metal mold from both sides in the Y direction. By sandwiching the winding portion 22 by the metal mold as described above, the winding portion 22 can be positioned in the Z direction and in the XY plane.

[0059] Next, a slide mold (not shown) is inserted into the central hole 24 of the winding portion 22. Next, a thermosetting material is injected into the inside of the mold. Next, the thermosetting material is solidified. Next, the mold is removed. Next, the fastening portion 50 is attached to the solidified thermosetting material. As a result, the holding member 40 is formed. That is, the intermediate structure 12 is produced.

[0060] According to this embodiment, by sandwiching the winding portion 22 with a metal mold (not shown) as described above, the winding portion 22 can be held so as not to move in the Z direction and the XY plane. That is, the holding member 40 of this embodiment can be formed so that the winding portion 22 is partially embedded. However, the present invention is not limited to this, and the method of forming the holding member 40 can be variously modified as necessary. For example, when positioning the winding portion 22, in addition to the upper curved surface portion 324, the lower curved surface portion 344 may be sandwiched by a lower metal mold (not shown) from both sides in the Y direction. Furthermore, the front and rear surfaces of the lower exposed portion 34 may be sandwiched by a lower metal mold from both sides in the X direction. According to this method, the winding portion 22 can be more reliably positioned in the XY plane.

[0061] Referring to FIG. 9, the structures of the upper exposed portion 32 and the lower exposed portion 34 can be modified in various ways as long as they allow the coil 20 to be positioned when the holding member 40 is formed.

[0062] For example, the entire upper surface of the upper exposed portion 32 may have an arc shape protruding upward in the YZ plane. That is, the upper exposed portion 32 may have only one upper curved surface portion 324. Whatever shape the upper exposed portion 32 has, it is sufficient that the upper curved surface portion 324 is exposed from the holding member 40 on both sides in the Y direction. Also, the entire lower surface of the lower exposed portion 34 may have an arc shape protruding downward in the YZ plane. That is, the lower exposed portion 34 may have only one lower curved surface portion 344. The lower exposed portion 34 may have only a lower flat portion 342. When the lower curved surface portion 344 is provided, it is sufficient that the lower curved surface portion 344 is exposed from the holding member 40 on both sides in the Y direction, regardless of what shape the lower exposed portion 34 has.

[0063] 9 and 10, according to this embodiment, the upper end (the end on the +Z side) of the upper exposed portion 32 is located below the upper end of the holding member 40, and the lower end of the lower exposed portion 34 is located below the lower end of the holding member 40. That is, the front and rear faces of the upper exposed portion 32 are covered by the holding member 40, and the front and rear faces of the lower exposed portion 34 are exposed from the holding member 40. However, the present invention is not limited to this, and the positional relationship of each of the upper exposed portion 32 and the lower exposed portion 34 to the holding member 40 can be modified in various ways as necessary.

[0064] The holding member 40 and the fastening portion 50 of this embodiment will be described below.

[0065] 6 and 7, the holding member 40 of this embodiment has a lower support portion 42, an upper support portion 45, two outer wall portions 48, and two connection portions 54 in addition to the two side walls 44. The holding member 40 of this embodiment has only the above-mentioned portions. However, the present invention is not limited to this. For example, the holding member 40 may have further portions in addition to the above-mentioned portions. Meanwhile, each of the above-mentioned portions may be provided as necessary.

[0066] 6 and 10, each of the side walls 44 in this embodiment is integrally formed with the holding member 40. In other words, each of the side walls 44 is a part of the holding member 40. More specifically, each of the side walls 44 is a middle part of the holding member 40 in the Z direction. When the winding part 22 is divided into four parts, namely, both side parts in the Y direction, a lower part, and an upper part, the side walls 44 completely cover both side parts of the winding part 22 in the Y direction in the XY plane. In detail, among the both side parts of the winding part 22 in the Y direction, the inner peripheral surface 222 and the outer peripheral surface 224 are completely covered by the two side walls 44. In addition, among the both side parts of the winding part 22 in the Y direction, the front end and the rear end are completely covered by the two side walls 44.

[0067] Each of the side walls 44 in the present embodiment has the structure described above. However, as long as the side walls 44 cover and insulate both sides of the winding portion 22 in the Y direction, the structure of each of the side walls 44 is not particularly limited.

[0068] 6 and 8 to 10, the lower support portion 42 in this embodiment is integrally formed with the holding member 40. In other words, the lower support portion 42 is a part of the holding member 40. More specifically, the lower support portion 42 is a lower portion (a portion on the -Z side) of the holding member 40. The lower support portion 42 has a flat plate shape extending parallel to the XY plane. With reference to FIGS. 6, 9 and 10, each of the side walls 44 extends upward from the lower support portion 42. That is, the lower support portion 42 supports the side walls 44.

[0069] 8 to 10, the lower support part 42 partially covers the lower part of the winding part 22 in the XY plane. In particular, of the lower part of the winding part 22, the inner circumferential surface 222 is completely covered by the lower support part 42. On the other hand, of the lower part of the winding part 22, the outer circumferential surface 224, the front end, and the rear end are partially covered by the lower support part 42.

[0070] More specifically, referring to Fig. 8, a lower opening 422 is formed in the lower support part 42. The lower opening 422 is a space that opens downward. The lower opening 422 is located in the middle of the lower support part 42 in the XY plane, and is surrounded by a lower surface 428 of the lower support part 42. A lower exposed part 34 that is a lower part of the winding part 22 is exposed by protruding downward from the lower opening 422. In more detail, referring to Figs. 9 and 10, the lower exposed part 34 protrudes downward beyond the lower surface 428 of the lower support part 42.

[0071] The lower support part 42 of the present embodiment has the above-mentioned structure. However, as long as the lower support part 42 covers and insulates the inner circumferential surface 222 of the lower part of the winding part 22 while exposing the lower exposed part 34 downward, the structure of the lower support part 42 is not particularly limited.

[0072] 6, 7, 9, and 10, the upper support portion 45 of this embodiment is integrally formed with the holding member 40. In other words, the upper support portion 45 is a part of the holding member 40. More specifically, the upper support portion 45 is an upper portion (a portion on the +Z side) of the holding member 40. With reference to FIGS. 6, 9, and 10, each of the side walls 44 extends vertically between the lower support portion 42 and the upper support portion 45. That is, the upper support portion 45 is supported by the side walls 44.

[0073] 6 and 7, the upper support portion 45 has a flat plate shape extending parallel to the XY plane as a whole. The upper support portion 45 has a front upper support portion 46 and a rear upper support portion 47. That is, the holding member 40 of this embodiment has the front upper support portion 46 and the rear upper support portion 47. The front upper support portion 46 is a portion of the upper support portion 45 that partially protrudes forward. The rear upper support portion 47 is a portion of the upper support portion 45 that partially protrudes backward. The front upper support portion 46 is located in front of the winding portion 22, and the rear upper support portion 47 is located behind the winding portion 22. Each of the front upper support portion 46 and the rear upper support portion 47 faces a part of the lower support portion 42 in the Z direction.

[0074] The upper support portion 45 of this embodiment has, in addition to the front upper support portion 46 and the rear upper support portion 47, two upper side walls 456 respectively corresponding to the side walls 44. Each of the upper side walls 456 is a portion of the upper support portion 45 that partially protrudes outward in the Y direction and is connected to the upper end of the corresponding side wall 44.

[0075] 7, 9, and 10, upper support portion 45 partially covers an upper portion of winding portion 22 in the XY plane. In particular, of the upper portion of winding portion 22, inner circumferential surface 222, the front end, and the rear end are completely covered by upper support portion 45. On the other hand, of the upper portion of winding portion 22, outer circumferential surface 224 is partially covered by upper support portion 45.

[0076] 6 and 7, an upper opening 452 is formed in upper support part 45. Upper opening 452 is a space that opens upward. Upper opening 452 is located in the middle of upper support part 45 in the XY plane. With reference to FIGS. 6 and 9, upper exposed part 32, which is a part of the upper part of winding part 22, is located inside upper opening 452 and is exposed from upper support part 45.

[0077] The upper support part 45 of the present embodiment has the above-mentioned structure. However, the present invention is not limited to this. As long as the upper support part 45 covers and insulates the inner circumferential surface 222 of the upper part of the winding part 22 while exposing the upper exposed part 32 upward and on both sides in the Y direction, the structure of the upper support part 45 is not particularly limited.

[0078] 6, 7 and 9, each of the outer wall portions 48 in this embodiment is integrally formed with the holding member 40. In other words, each of the outer wall portions 48 is a part of the holding member 40. The outer wall portions 48 are provided on the lower support portion 42 so as to correspond to the side walls 44, respectively.

[0079] 6 and 7, the outer wall portions 48 are located on both sides of the lower support portion 42 in the Y direction. Each of the outer wall portions 48 extends upward from the lower support portion 42 while partially surrounding the corresponding side wall 44 in the XY plane. More specifically, each of the outer wall portions 48 has an inner circumferential surface 482 in the XY plane. An intermediate portion of each of the inner circumferential surfaces 482 in the X direction extends linearly along the X direction. Both end portions of each of the inner circumferential surfaces 482 in the X direction extend inward in the Y direction while drawing an arc. A groove is formed between each of the inner circumferential surfaces 482 and the corresponding side wall 44.

[0080] Each of the outer wall portions 48 in this embodiment has the structure described above. However, the present invention is not limited to this. For example, each of the outer wall portions 48 may be formed separately from the lower support portion 42 and then attached and fixed to the lower support portion 42. Also, each of the outer wall portions 48 may be provided as necessary.

[0081] 1, each of the connection parts 54 in this embodiment is a portion for fixing a bus bar 80 made of a conductor such as metal to the holding member 40. With reference to FIGS. 6 and 7, each of the connection parts 54 in this embodiment is integrally formed with the holding member 40. In other words, each of the connection parts 54 is a part of the holding member 40. The connection parts 54 in this embodiment are provided so as to correspond to each of the outer wall parts 48. One of the connection parts 54 protrudes forward from the corresponding outer wall part 48, and the other of the connection parts 54 protrudes rearward from the corresponding outer wall part 48. A connection hole 56 is formed in each of the connection parts 54. Each of the connection holes 56 is a hole with a bottom recessed downward and opens upward.

[0082] Each of the connection parts 54 in the present embodiment has the structure described above. However, the present invention is not limited to this. For example, the arrangement of the connection parts 54 is not particularly limited. Also, each of the connection parts 54 may be provided as necessary.

[0083] With reference to Fig. 1, each of the fastening portions 50 in this embodiment is a portion for fixing the reactor 10 to an object (not shown) such as a circuit board. With reference to Figs. 6 and 7, the holding member 40 in this embodiment is provided with four fastening portions 50 for fastening the reactor 10 to the object. However, the present invention is not limited to this. For example, the number of fastening portions 50 may be three or less, or five or more. Moreover, the fastening portions 50 may be provided as necessary.

[0084] 6 and 7, the fastening portion 50 of this embodiment is located outside the winding portion 22 in the X direction. More specifically, two of the fastening portions 50 protrude forward from the lower support portion 42, and the other two of the fastening portions 50 protrude rearward from the lower support portion 42. With reference to FIGS. 8 and 9, the lower surface 508 of each of the fastening portions 50 is at the same position as the lower surface 428 of the lower support portion 42 in the Z direction, and extends continuously from the lower surface 428. That is, each of the lower surfaces 508 of the fastening portions 50 is flush with the lower surface 428 of the lower support portion 42. With reference to FIGS. 6 to 8, a fastening hole 52 is formed in each of the fastening portions 50. Each of the fastening holes 52 penetrates the fastening portion 50 in the Z direction.

[0085] 6, in this embodiment, the parts of the holding member 40 (the lower support part 42, the side wall 44, the upper support part 45, the outer wall part 48 and the connection part 54) are integrally formed with one another. Meanwhile, according to this embodiment, two of the fastening parts 50 are located directly below the slide path of the slide die (not shown). It is difficult to mold the fastening parts 50 thus arranged simultaneously with the holding member 40. For this reason, in this embodiment, each of the fastening parts 50 is attached to the lower support part 42 after the holding member 40 is integrally formed with one another.

[0086] In general, when an additional portion such as the fastening portion 50 cannot be formed simultaneously with the holding member 40, the reactor 10 (see FIG. 1) excluding the additional portion is produced, and then molding is performed to form the additional portion. On the other hand, according to the present embodiment, after the holding member 40 is formed, each of the fastening portions 50 that have been manufactured in advance is attached to the lower support portion 42. According to this manufacturing method, each of the fastening portions 50 can be disposed on the outer side in the X direction of the lower support portion 42 without increasing the number of molding steps. That is, according to the present embodiment, the manufacturing cost of the reactor 10 can be reduced. However, the present invention is not limited thereto. For example, each of the fastening portions 50 may be disposed on the outer side in the Y direction of the lower support portion 42. According to this arrangement, the fastening portions 50 can be formed simultaneously and integrally with the holding member 40, and thus the manufacturing cost of the reactor 10 can be further reduced.

[0087] A method for forming the magnetic core 60 (see FIG. 12) of this embodiment will now be described.

[0088] 1 and 6 together with Fig. 12, the magnetic core 60 of this embodiment is formed by injecting a magnetic slurry made of a composite magnetic body 60M into the intermediate structure 12. In detail, referring to Fig. 6 together with Fig. 1, the magnetic core 60 of this embodiment is injection molded so as to fill the inside of the central hole 24 of the intermediate structure 12 and surround each of the side walls 44 of the intermediate structure 12 in the XY plane. That is, the reactor 10 of this embodiment includes the intermediate structure 12 and the injection molded magnetic core 60.

[0089] If the coil 20 (particularly the winding portion 22) is exposed at the portion where the magnetic slurry is injected, the winding portion 22 may be directly covered with the magnetic slurry. That is, the winding portion 22 may not be insulated from the formed magnetic core 60.

[0090] On the other hand, according to the present embodiment, each of the side walls 44 of the holding member 40 is located between the winding portion 22 and the magnetic core 60 in the Y direction, and insulates the winding portion 22 from the magnetic core 60. In detail, the portion of the winding portion 22 located above the lower support portion 42 is completely covered and insulated by the holding member 40, except for the upper exposed portion 32. The upper exposed portion 32 is in a blind spot from the portion from which the magnetic slurry is injected. In addition, the lower support portion 42 covers and hides the portion of the winding portion 22 located below the lower support portion 42 in the Z direction. Therefore, the reactor 10 having the coil 20 partially embedded inside the holding member 40 can be provided with a magnetic core 60 shaped like an EE core.

[0091] According to this embodiment, the winding portion 22 does not come into contact with the magnetic slurry when the magnetic core 60 is injection molded. However, the method of forming the magnetic core 60 is not limited to this embodiment. For example, the magnetic core 60 may be a cast core.

[0092] As described above, the reactor of this embodiment 10 can be fabricated using a coil 20 having a single winding portion 22 and a magnetic core 60 shaped like an EE core. That is, according to this embodiment, it is possible to provide a reactor 10 including a coil 20 partially embedded inside a holding member 40, and having a relatively large inductance.

[0093] Referring to FIG. 12, as described above, the magnetic core 60 of this embodiment is formed only from the composite magnetic body 60M. However, the present invention is not limited to this. For example, the magnetic core 60 may include a dust core (not shown) made of a soft magnetic material in addition to the portion made of the composite magnetic body 60M. That is, the magnetic core 60 may be at least partially formed from the composite magnetic body 60M. For example, a portion made of the composite magnetic body 60M may be formed by embedding a plurality of small pieces of the dust core. When the magnetic core 60 includes the dust core, the inductance of the reactor 10 (see FIG. 1) can be increased.

[0094] The magnetic core 60 may be formed only from dust cores. For example, instead of injection molding, the magnetic core 60 may be formed by fixing a plurality of dust cores to each other with an adhesive. That is, the magnetic core 60 may be an assembly in which a plurality of dust cores are joined to each other. By forming the magnetic core 60 only from dust cores, the inductance of the reactor 10 (see FIG. 1) can be further increased.

[0095] 1 and 6, in this embodiment, each of the side walls 44 does not have a hole that opens toward both the winding portion 22 and the outer leg 66. This structure allows the winding portion 22 to be more reliably insulated from the magnetic core 60. However, the present invention is not limited to this. For example, each of the side walls 44 may have a hole formed therein that does not interfere with insulation.

[0096] The upper exposed portion 32 of the present embodiment is visible when the reactor 10 is viewed along the Y direction. However, the present invention is not limited to this. For example, referring to FIG. 4 and FIG. 5, the upper side wall 456 of the upper exposed portion 32 Upper curved part 324 The holding member 40 may be spaced apart in the Y direction from the upper exposed portion 32 and positioned outside the entire upper exposed portion 32 in the Y direction. In other words, the upper exposed portion 32 may be surrounded seamlessly in the XY plane by the holding member 40. According to this modification, the winding portion 22 can be more reliably insulated from the magnetic core 60.

[0097] 4, the magnetic core 60 of the present embodiment is located between the upper exposed portion 32 and the lower exposed portion 34 of the winding portion 22 in the Z direction. That is, the magnetic core 60 of the present embodiment is arranged so that the position of the magnetic core 60 in the Z direction does not overlap the positions of the upper exposed portion 32 and the lower exposed portion 34 in the Z direction. This arrangement allows the winding portion 22 to be more reliably insulated from the magnetic core 60. However, the present invention is not limited to this. For example, when the upper exposed portion 32 is surrounded seamlessly by the holding member 40 in the XY plane, the position of the magnetic core 60 in the Z direction may overlap the position of the upper exposed portion 32 in the Z direction.

[0098] 1, the lower support portion 42, the front upper support portion 46, the rear upper support portion 47, and the outer wall portion 48 of the holding member 40 of this embodiment are provided as follows. With reference to FIG. 5, the lower support portion 42 is in contact with the lower surface 60L of the magnetic core 60 and supports the lower surface 60L. With reference to FIGS. 1 and 4, the front upper support portion 46 and the rear upper support portion 47 are in contact with the upper surface 60U of the magnetic core 60. With reference to FIG. 2, each of the outer wall portions 48 is in contact with the outer peripheral surface 60E of the magnetic core 60 in the XY plane. In particular, each of the inner peripheral surfaces 482 of the outer wall portions 48 is in contact with the outer peripheral surface 60E of the magnetic core 60 in the XY plane.

[0099] Since the lower support portion 42, the front upper support portion 46, the rear upper support portion 47 and the outer wall portion 48 in this embodiment are arranged as described above, the magnetic core 60 can be injection molded at a predetermined position defined by the lower support portion 42, the front upper support portion 46, the rear upper support portion 47 and the outer wall portion 48.

[0100] In addition, the magnetic core 60 of this embodiment is sandwiched between the front upper support portion 46, the rear upper support portion 47 and the lower support portion 42 in the Z direction, and has two portions in each of the X direction and the Y direction. Inner peripheral surface 482 . That is, the magnetic core 60 of this embodiment is reliably positioned so as not to move in the Z direction and in the XY plane. This structure can prevent a change in inductance due to misalignment of the magnetic core 60, and can also prevent damage to the magnetic core 60. However, the present invention is not limited to this. For example, the front upper support portion 46, the rear upper support portion 47, and the outer wall portion 48 may be provided as necessary.

[0101] The reactor 10 of this embodiment will be described below.

[0102] 1, the reactor 10 of this embodiment is fixed to an object (not shown) such as a circuit board when in use. At that time, four nuts 82 are attached to the fastening holes 52 of the four fastening parts 50 of the reactor 10. The nuts 82 may be press-fitted into the fastening holes 52, or may be insert-molded into the fastening parts 50 when the fastening parts 50 are molded. Next, a screw (not shown) is screwed into the nuts 82 to fix the fastening parts 50 to the object.

[0103] The reactor 10 of this embodiment is fixed to an object (not shown) and then connected to a power source (not shown) using two bus bars 80. At this time, two nuts 84 are attached to the connection holes 56 of the two connection parts 54, respectively. The nuts 84 may be press-fitted into the connection holes 56, or may be insert-molded into the connection parts 54 when the holding member 40 is molded. Next, the upper ends of the bus bars 80 are fixed and connected to the terminals 28 of the coil 20 by welding or the like. Next, a screw (not shown) is screwed into the nut 84 through a through hole (not shown) at the lower end of the bus bar 80 and a through hole (not shown) of a conductive member (not shown) made of a conductor, thereby fixing and connecting the bus bars 80 to the two conductive members, respectively. As a result, when the reactor 10 is used, a large current flows from the power source to the coil 20 via the conductive member.

[0104] Since the magnetic core 60 of this embodiment is formed from a composite magnetic body 60M (see FIG. 12), it is difficult to become magnetically saturated even when a large current flows through the coil 20. Therefore, the reactor 10 of this embodiment can be made smaller while maintaining its magnetic characteristics. That is, according to this embodiment, a small reactor 10 suitable for a large current can be obtained.

[0105] In general, a reactor 10 having a magnetic core 60 made of only a composite magnetic body 60M (see FIG. 12) has a lower initial inductance when a relatively low current of about 30 to 40 A flows through the coil 20, compared to a reactor having a dust core. Therefore, in order to obtain the necessary boost performance, it is necessary to flow the current for a relatively long time. However, the core loss increases as the current flows. On the other hand, the magnetic core 60 of this embodiment is formed from a low-loss material described below, which can reduce the core loss.

[0106] The magnetic powder 60P (see FIG. 12) of the composite magnetic body 60M (see FIG. 12) contained in the magnetic core 60 of this embodiment has a composition formula of Fe X1 B X2 S X3 P X4 C X5 Cu X6 Cr X7The alloy powder is represented by the formula: X1+X2+X3+X4+X5+X6+X7=100 at%, 79≦X1≦86 at%, 4≦X2≦13 at%, 0≦X3≦8 at%, 1≦X4≦14 at%, 0≦X5≦5 at%, 0.4≦X6≦1.4 at%, 0≦X7≦3 at%. This composition can reduce the core loss of the magnetic core 60. However, the present invention is not limited to this, and the composition of the magnetic powder 60P may be set in consideration of various magnetic properties required for the reactor 10.

[0107] The magnetic powder 60P (see FIG. 12) may be the alloy powder in which part of the Fe in the above composition formula is replaced with one or more elements selected from Co, Ni, V, Nb, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Zn, Ti, Al, Mn, S, O, N, Y, and rare earth elements. In this case, the content of one or more elements selected from Co, Ni, V, Nb, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Zn, Ti, Al, Mn, S, O, N, Y, and rare earth elements is 3 at% or less of the entire composition. In addition, the total of one or more elements selected from Co, Ni, V, Nb, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Zn, Ti, Al, Mn, S, O, N, Y and rare earth elements and Fe is X1 at%.

[0108] From the viewpoint of further reducing the core loss of the magnetic core 60, it is preferable that the alloy powder having the above composition contains αFe nanocrystals. The shape of the nanocrystals is preferably substantially spherical. In addition, it is preferable that the average particle size (D50) of the nanocrystals when approximated to a sphere is 5 nm or more and 50 nm or less.

[0109] Referring to FIG. 4, when a current flows through the winding portion 22 during use of the reactor 10, heat is generated in the winding portion 22 and the magnetic core 60. If the generated heat is accumulated, the reactor 10 may not operate as designed. Furthermore, the reactor 10 may be damaged. Meanwhile, the bottom surface 22L of the winding portion 22 in this embodiment is located below the holding member 40. According to this arrangement, when the reactor 10 is fixed to an object (not shown) such as a circuit board, the bottom surface 22L can be brought into contact with the object to dissipate heat. That is, the bottom surface 22L of this embodiment functions as a heat dissipation portion. Also, referring to FIG. 1, the upper exposed portion 32 of this embodiment functions as a heat dissipation portion that radiates heat into the air. However, the present invention is not limited to this. For example, the position of the bottom surface 22L of the winding portion 22 in the Z direction can be changed as necessary.

[0110] 2, the reactor 10 of this embodiment has a shape that is rotationally symmetrical about 180 degrees when viewed from above along the Z direction. In particular, the shape of the reactor 10 when rotated 180 degrees around an axis extending parallel to the Z direction is the same as the shape before rotation, except for tolerances. This structure allows the same parts to be used for the two bus bars 80, thereby reducing the manufacturing cost of the reactor 10. In addition, the strength design of the reactor 10 becomes easier.

[0111] The reactor 10 of this embodiment has a shape that is rotationally symmetrical about 180 degrees, including the upper exposed portion 32 of the winding portion 22. More specifically, each of the turns 22T exposed upward extends straight along the Y direction. However, the present invention is not limited to this. For example, each of the turns 22T may be slightly oblique to the Y direction. That is, it is sufficient that the reactor 10 has a shape that is substantially rotationally symmetrical about 180 degrees when viewed from above along the Z direction.

[0112] In addition to the modifications already described, the reactor 10 of this embodiment can be modified in various other ways. Two modifications of the reactor 10 will be described below.

[0113] 14 and 15 with FIG. 4 and FIG. 5, a reactor 10A according to a first modified example includes the same coil 20, magnetic core 60, and fastening portion 50 as the reactor 10, but includes a holding member 40A different from the holding member 40 of the reactor 10. The lower support portion 42 of the holding member 40A is located lower than the lower support portion 42 of the holding member 40, and the outer wall portion 48A of the holding member 40A extends longer in the Z direction than the outer wall portion 48 of the holding member 40. Except for this difference, the holding member 40A has the same structure as the holding member 40.

[0114] According to this modification, lower surface 508 of fastening portion 50 can be made flush with bottom surface 22L of winding portion 22. That is, the lower surface of the entire lower support portion 42 including lower surface 508 of fastening portion 50 can be made flush with bottom surface 22L of winding portion 22. According to this modification, it becomes easier to manage the height of reactor 10A when manufacturing reactor 10A, and thus the manufacturing cost of reactor 10A can be reduced.

[0115] Comparing FIG. 16 with FIG. 1, the reactor 10B according to the second modification includes the same coil 20, magnetic core 60, and fastening portion 50 as the reactor 10, but includes a holding member 40B different from the holding member 40 of the reactor 10. The holding member 40B has an upper wall portion 454B that the holding member 40 does not have. The upper wall portion 454B is provided so as to partially close the upper opening 452 of the upper support portion 45. More specifically, the upper wall portion 454B extends over the entire upper opening 452 in the X direction so as to cover the intermediate portion in the Y direction of the upper flat portion 322 of the winding portion 22. The holding member 40B has the same structure as the holding member 40 except for this difference.

[0116] According to this modification, it is possible to partially block upper exposed portion 32 of winding portion 22 while still allowing molding of holding member 40B, thereby further improving the insulation of winding portion 22. [Explanation of symbols]

[0117] 10,10A,10B Reactor 12 Intermediate structure 20 Coil 22 Winding part 22L Bottom surface 22T Turn 222 Inner peripheral surface 224 Outer peripheral surface 24 Central hole 28 Terminal 32 Upper exposed part 322 Upper flat part 324 Upper curved part 34 Lower exposed part 342 Lower flat part 344 Lower curved part 40, 40A, 40B Holding member 42 Lower support part 422 Lower opening 428 Bottom surface 44 Side wall 45 Upper support part 452 Upper opening 454B Upper wall part 456 Upper side wall 46 Front upper support part 47 Rear upper support part 48, 48A Outer wall part 482 Inner peripheral surface 50 Fastening part 508 Bottom surface 52 Fastening hole 54 Connection part 56 Connection hole 60 Magnetic core 60U Upper surface 60L Lower surface 60E Outer peripheral surface 60M Composite magnetic material 60B Binder 60P Magnetic powder 62 Middle leg 64 Outer part 66 Outer leg 68 Connecting part AX Central axis 80 Bus bar 82, 84 Nut

Claims

1. A reactor including a coil, a holding member, and a magnetic core, The coil has a winding portion, The winding portion is wound around a single central axis extending along a front-rear direction, The winding portion has an upper exposed portion and a lower exposed portion, the upper exposed portion and the lower exposed portion are located on opposite sides of the winding portion in a vertical direction perpendicular to the front-rear direction, the winding portion is partially embedded within the holding member, each of the upper exposed portion and the lower exposed portion is exposed from the holding member in the up-down direction; The upper exposed portion has an upper curved surface portion, the upper curved surface portion is exposed from the holding member on both sides in a lateral direction perpendicular to both the front-rear direction and the up-down direction, The magnetic core has a center leg and two outer portions, Each of the outer parts has an outer leg and two connecting parts, The middle leg is surrounded by the winding portion in a vertical plane perpendicular to the front-rear direction, The winding portion is located between the two outer legs in the lateral direction, In each of the outer parts, the connecting portion connects both ends of the outer leg in the front-rear direction to both ends of the middle leg in the front-rear direction, The holding member has two side walls respectively corresponding to the outer legs, Each of the side walls is located between the corresponding outer leg and the winding portion in the lateral direction, The holding member is molded so as to cover the inner peripheral surface of the vertical plane of the winding portion. Reactor.

2. The reactor according to claim 1, The magnetic core is a gapless core and is at least partially made of a composite magnetic material; The composite magnetic body includes a binder and a magnetic powder dispersed in the binder. Reactor.

3. The reactor according to claim 2, The magnetic core is made of only the composite magnetic body. Reactor.

4. A reactor according to claim 2 or claim 3, The magnetic powder of the composite magnetic body has a composition formula of Fe, excluding unavoidable impurities. Ｘ１ B Ｘ２ S Ｘ３ P Ｘ４ C Ｘ５ Cu Ｘ６ Cr Ｘ７ X1+X2+X3+X4+X5+X6+X7=100 at%, 79≦X1≦86 at%, 4≦X2≦13 at%, 0≦X3≦8 at%, 1≦X4≦14 at%, 0≦X5≦5 at%, 0.4≦X6≦1.4 at%, and 0≦X7≦3 at%. Reactor.

5. The reactor according to claim 4, The magnetic powder is an alloy powder in which a part of Fe is replaced with one or more elements selected from the group consisting of Co, Ni, V, Nb, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Zn, Ti, Al, Mn, S, O, N, Y, and rare earth elements, and the alloy powder is selected from the group consisting of Co, Ni, V, Nb, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Zn, Ti, Al, Mn, S, O, N, Y, and rare earth elements. One or more elements selected from the group consisting of N, Zn, Ti, Al, Mn, S, O, N, Y, and rare earth elements are 3 at% or less of the entire composition, and the total of one or more elements selected from the group consisting of Co, Ni, V, Nb, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Zn, Ti, Al, Mn, S, O, N, Y, and rare earth elements and Fe is X1 at%. Reactor.

6. The reactor according to claim 4 or 5, The alloy powder contains α-Fe nanocrystals, The average particle size (D50) of the nanocrystals is 5 nm or more and 50 nm or less. Reactor.

7. A reactor according to any one of claims 1 to 6, Each of the side walls does not have a hole that opens toward both the winding portion and the outer leg. Reactor.

8. A reactor according to any one of claims 1 to 7, The lower exposed portion has a lower curved surface portion, The lower curved surface portion is exposed from the holding member on both sides in the lateral direction. Reactor.

9. The reactor according to claim 8, The upper exposed portion has an upper flat portion and two of the upper curved portions, the upper curved surface portions are located on opposite sides of the upper flat surface portions in the lateral direction, The lower exposed portion has a lower flat portion and two of the lower curved portions, The lower curved surface portions are located on opposite sides of the lower flat surface portions in the lateral direction. Reactor.

10. A reactor according to any one of claims 1 to 9, The magnetic core is located between the upper exposed portion and the lower exposed portion in the vertical direction. Reactor.

11. A reactor according to any one of claims 1 to 10, The holding member has a lower support portion, a front upper support portion, and a rear upper support portion, The lower support portion supports a lower surface of the magnetic core, the front upper support portion is located in front of the winding portion and in contact with an upper surface of the magnetic core, The rear upper support portion is located behind the winding portion and is in contact with the upper surface of the magnetic core. Reactor.

12. The reactor according to claim 11, the holding member is provided with a fastening portion for fastening the reactor to an object, The lower support portion is integrally formed with the holding member, The fastener is attached to the lower support. Reactor.

13. The reactor according to claim 12, The lower surface of the fastening portion is flush with the bottom surface of the winding portion. Reactor.

14. A reactor according to any one of claims 1 to 13, The holding member has an outer wall portion, The outer wall portion is in contact with an outer peripheral surface of the magnetic core in a horizontal plane perpendicular to the up-down direction. Reactor.

15. A reactor according to any one of claims 1 to 14, The reactor has a shape that is rotationally symmetrical about 180 degrees when viewed from above along the vertical direction. Reactor.

16. A reactor including a coil, a holding member, and a magnetic core, The coil has a winding portion, The winding portion is wound around a single central axis extending along a front-rear direction, the winding portion is partially embedded within the holding member, The magnetic core is a gapless core, The magnetic core has a center leg and two outer portions, Each of the outer parts has an outer leg and two connecting parts, The middle leg is surrounded by the winding portion in a vertical plane perpendicular to the front-rear direction, The winding portion is located between the two outer legs in a lateral direction perpendicular to the front-rear direction, In each of the outer parts, the connecting portion connects both ends of the outer leg in the front-rear direction to both ends of the middle leg in the front-rear direction, The retaining member has a front upper support portion, a rear upper support portion, and an outer wall portion, the front upper support portion is located in front of the winding portion and is in contact with an upper surface of the magnetic core in a vertical direction perpendicular to both the front-rear direction and the lateral direction, the rear upper support portion is located rearward of the winding portion and in contact with an upper surface of the magnetic core, the outer wall portion is in contact with an outer circumferential surface of the magnetic core in a horizontal plane perpendicular to the up-down direction, the holding member is provided with a fastening portion for fastening the reactor to an object, The fastening portion is integrally formed with the holding member, The holding member is molded so as to cover the inner peripheral surface of the vertical plane of the winding portion. Reactor.

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