Reactor

Abstract

To provide a reactor with excellent manufacturing efficiency even when a gap thickness is different.SOLUTION: Two or more legs of an annular core 3 of a reactor 1 include a first leg 31a and a second leg 31b that differ in the presence or absence of gaps or the total thickness of the gaps. A first joint portion 32a of a yoke portion 32 to be joined to a first leg portion 31a and a second joint portion 32b of a yoke portion 32 to be joined to a second leg portion 31b have different protruding heights or recessed depths, and a difference in height between the first joint portion 32a and the second joint portion 32b is half a difference in the total thickness of a first gap 4a and a second gap 4b of the first leg portion 31a and the second leg portion 31b.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a reactor having a core and a coil. [Background technology]

[0002] A reactor has a coil and a core that is inserted into the coil. To electrically insulate the coil from the core, the core is usually covered with a resin material, and the wound coil is attached to the core from above the resin material. This reactor is a passive element that converts electrical energy into magnetic energy and stores and releases it.

[0003] Such reactors are used in a wide variety of applications. Representative reactors include boost reactors incorporated in on-board boost circuits such as drive systems for hybrid and electric vehicles, series reactors connected in series to motor circuits to limit current during short circuits, parallel reactors to stabilize current sharing between parallel circuits, current limiting reactors to limit current during short circuits and protect machines connected to them, starting reactors connected in series to motor circuits to limit starting current, shunt reactors connected in parallel to transmission lines to compensate for leading reactive power and suppress abnormal voltages, neutral reactors connected between the neutral point and the ground to limit earth-fault current that flows in the event of an earth-fault in the power system, and arc-suppression reactors to automatically extinguish arcs that occur in the event of a single-line earth fault in a three-phase power system.

[0004] In a reactor, there is a risk of magnetic saturation, where the magnetic flux density becomes saturated as the magnetic field increases. When a reactor becomes magnetically saturated, the magnetic permeability becomes very low, just like an air core, and the inductance drops sharply. Therefore, when a reactor becomes magnetically saturated, there is a risk that an excessive current will flow in the reactor and the circuit in which the reactor is incorporated. For this reason, a gap is provided in the core. The gap increases the magnetic resistance of the core. When the magnetic resistance of the core increases, the increase in magnetic flux density relative to the strength of the magnetic field becomes more gradual, and magnetic flux saturation of the reactor is suppressed.

[0005] There is a reactor with a θ-shaped core. The θ-shaped core has a center leg, two outer legs, and a yoke. Two outer legs are placed on either side of the center leg. The yoke sandwiches the three legs from both sides. This gives the θ-shaped core a shape of two connected rings with a common center leg. Coils are inserted into both outer legs and the center leg.

[0006] In a reactor with a θ-shaped core, non-uniformity in the magnetic path occurs. The magnetic flux generated in the outer legs and passing through a magnetic path with magnetic path length L1 flows around the center leg from both outer legs. The magnetic flux generated in the center leg and passing through a magnetic path with magnetic path length L1, and the magnetic flux generated in the other outer leg, located far away from the center leg, and passing through a magnetic path length L2, flow around the outer leg. The magnetic resistance of the core excluding the gap is proportional to the magnetic path length. Therefore, the magnetic resistance of the core excluding the gap in the outer legs is different from the magnetic resistance of the core excluding the gap in the center leg.

[0007] Therefore, in order to eliminate the difference between the magnetic resistance of the magnetic path that passes through the outer leg and the magnetic path that passes through the center leg, the total thickness of the gap provided in the outer leg is made different from the total thickness of the gap provided in the center leg (for example, see Patent Document 1). In other words, the difference in magnetic resistance due to the difference in magnetic path length is offset by the difference in magnetic resistance due to the difference in gap thickness.

[0008] There is also a reactor with one ring-shaped core. The core of this reactor has two legs sandwiched between yoke parts from both sides to form a ring shape. Even in a reactor with one ring-shaped core, the thickness of the gap provided between one leg and the other leg may be made different. For example, if only one leg is placed in the case, the external leakage magnetic flux from the gap between both legs will be different, and non-uniformity of the magnetic path will also occur. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2018-26504 A Summary of the Invention [Problem to be solved by the invention]

[0010] The total length of the legs of the core is La, a gap with a thickness of G1 is provided at one location on one leg, and a gap with a thickness of G2 is provided at one location on the other leg. In this case, one leg has two leg blocks with a total length of (La-G1) / 2 and a gap with a thickness of G1 between the leg blocks. The other leg has two leg blocks with a total length of (La-G2) / 2 and a gap with a thickness of G2 between the leg blocks. A pair of yoke parts sandwiching both legs are the same shape and size.

[0011] In this way, when the gap thicknesses in the two legs are different, the core requires one type of yoke and two types of leg blocks, a total of three types of core materials.When the gap thicknesses in the three legs are all different, the core requires one type of yoke and three types of leg blocks, a total of three types of core materials.

[0012] Therefore, when the gap thickness is made different, at least three types of dies and manufacturing equipment are required to manufacture the yoke and two or more types of leg blocks. Therefore, the manufacturing efficiency of the reactor is lower than that of a reactor with a uniform gap. In addition, there is a risk of misassembly of the two types of leg blocks, which reduces the yield and also reduces the manufacturing efficiency of the reactor.

[0013] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a reactor that has excellent manufacturing efficiency even when the gap thickness is changed. [Means for solving the problem]

[0014] The reactor of the present invention is a reactor having an annular core and a coil, wherein the annular core has two or more legs and a pair of yoke portions connecting the legs, one or more of the legs has a gap, the two or more legs include a first leg and a second leg which differ in the presence or absence of the gap or in the total thickness of the gap, the yoke portion has each joint which joins to an end surface of the leg, each of the joints includes a first joint which joins to the first leg and a second joint which joins to the second leg, the first joint and the second joint have different heights along the extension direction of the first leg and the second leg, and the difference in height between the first joint and the second joint is half the difference in the total thickness of the gap between the first leg and the second leg. Effect of the Invention

[0015] According to the present invention, even if the gap thickness is made different, the core is made of one type of yoke portion and one type of leg block, and a reactor with excellent manufacturing efficiency can be obtained. [Brief description of the drawings]

[0016] [Figure 1] 1 is a plan view showing an overall configuration of a reactor according to a first embodiment. [Diagram 2] FIG. 2 is a plan view showing the configuration of an annular core according to the first embodiment. [Diagram 3] FIG. 11 is a plan view showing the configuration of an annular core according to a second embodiment. [Figure 4] FIG. 11 is a plan view showing the configuration of an annular core according to a third embodiment. [Diagram 5] FIG. 11 is a plan view showing the configuration of an annular core according to a fourth embodiment. [Figure 6] FIG. 13 is a plan view showing the configuration of an annular core according to a fifth embodiment. [Figure 7] FIG. 13 is a plan view showing the configuration of an annular core according to a sixth embodiment. [Figure 8] FIG. 13 is a plan view showing an overall configuration of a reactor according to a seventh embodiment. [Figure 9] FIG. 13 is a plan view showing the configuration of an annular core according to a seventh embodiment. [Figure 10] FIG. 13 is a plan view showing an overall configuration of a reactor according to an eighth embodiment. [Figure 11] FIG. 13 is a plan view showing the configuration of an annular core according to a ninth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, reactors according to embodiments of the present invention will be described with reference to the drawings. In each drawing, thickness, dimensions, positional relationships, ratios, shapes, and the like may be emphasized for ease of understanding, but the present invention is not limited to such emphasis.

[0018] 1 shows the overall configuration of a reactor according to the first embodiment. This reactor 1 includes two coils 2 and one annular core 3. The two coils 2 are attached to the annular core 3. A current flows through the coil 2, which generates a magnetic flux according to the number of turns, and the annular core 3 becomes a closed magnetic circuit and passes the magnetic flux generated by the coil 2 according to a magnetic permeability higher than that of a vacuum. In other words, the reactor 1 is a passive element that converts electric energy into magnetic energy and stores and releases it.

[0019] The coil 2 is a cylindrically wound body made of conductive wire such as copper wire. The coil 2 is formed by winding the conductive wire in a spiral shape while shifting the winding position for each turn along the winding axis. The two coils 2 are attached to the annular core 3 via an insulating material (not shown) such as a resin member.

[0020] The annular core 3 is a magnetic body such as a dust core, a ferrite core, a metal composite core, or a laminated steel plate. The dust core is a powder compact obtained by compressing magnetic powder and annealing it. The magnetic powder is mainly composed of iron, and examples of the magnetic powder include pure iron powder, permalloy (Fe-Ni alloy) mainly composed of iron, Si-containing iron alloy (Fe-Si alloy), sendust alloy (Fe-Si-Al alloy), amorphous alloy, nanocrystalline alloy powder, and a mixture of two or more of these powders. The metal composite core is a core formed by kneading and molding magnetic powder and resin.

[0021] Fig. 2 is a plan view showing a detailed configuration of the annular core 3 of the first embodiment. As shown in Fig. 2, the annular core 3 includes a first leg 31a, a second leg 31b, and a pair of yoke parts 32. The first leg 31a, the second leg 31b, and the pair of yoke parts 32 are combined to form the annular core 3, which is a closed magnetic circuit having a ring shape. The first leg 31a and the second leg 31b are fitted into the coil 2, and are magnetic flux generating parts that generate magnetic flux. The yoke part 32 is a connecting part that connects the first leg 31a and the second leg 31b with magnetic flux.

[0022] The first leg 31a and the second leg 31b are arranged in parallel. The pair of yoke parts 32 are also arranged in parallel so as to extend in a direction perpendicular to the first leg 31a and the second leg 31b. The pair of yoke parts 32 are arranged so as to sandwich the first leg 31a and the second leg 31b from both ends. Each of the yoke parts 32 has a first joint part 32a that joins the first leg 31a and a second joint part 32b that joins the second leg 31b. The end face of the first leg 31a is butted against the first joint part 32a and joined with an adhesive. The end face of the second leg 31b is butted against the second joint part 32b and joined with an adhesive. As a result, the annular core 3 forms a closed ring shape.

[0023] The first leg 31a is formed by two leg blocks 33a connected together. A first gap 4a is interposed between the two leg blocks 33a. The second leg 31b is formed by two leg blocks 33b connected together. A second gap 4b is interposed between the two leg blocks 33b. The first gap 4a and the second gap 4b are located at the center in the longitudinal direction of the first leg 31a and the second leg 31b. The leg blocks 33a on both sides of the first gap 4a have the same overall length Ba. The leg blocks 33b on both sides of the second gap 4b have the same overall length Bb.

[0024] The first gap 4a and the second gap 4b are magnetic gaps whose magnetic permeability is orders of magnitude lower than that of the annular core 3. The first gap 4a and the second gap 4b are, for example, plate-shaped spacers or air gaps. The plate-shaped spacer is, for example, a ceramic material formed into a flat plate shape. It is a non-magnetic material, ceramic such as alumina or zirconia, a non-metal, resin, carbon fiber, or a composite material of two or more of these materials formed into a flat plate shape, or gap paper. The air gap is a gap without a magnetic material.

[0025] The thickness Ga of the first gap 4a of the first leg 31a and the thickness Gb of the second gap 4b of the second leg 31b are different to eliminate non-uniformity of the magnetic path. The first gap 4a of the first leg 31a is thicker than the second gap 4b of the second leg 31b. As shown in the following formula (1), when the thickness Gb of the second gap 4b of the second leg 31b is subtracted from the thickness Ga of the first gap 4a of the first leg 31a, the first gap 4a and the second gap 4b have a thickness difference D.

[0026] D = Ga - Gb (1)

[0027] The pair of yoke parts 32 are of the same shape and size, and are arranged so as to be symmetrical with respect to a line perpendicular to the extending direction of the first leg part 31a and the second leg part 31b. The second joint part 32b on the side of the second leg part 31b having the thin second gap 4b is arranged opposite to the second joint part 32b of the other yoke part 32, and the first gap 4a and the second gap 4b protrude from the first joint part 32a by half the thickness difference D. The protruding direction of the second joint part 32b is the extending direction of the second leg part 31b. On the other hand, the first joint part 32a on the side of the first leg part 31a having the thick first gap 4a is flat and does not protrude. That is, as shown in the following formula (2), the distance Lb between the protruding second joints 32b is shorter than the distance La between the flat first joints 32a by the thickness difference D between the first gap 4a and the second gap 4b.

[0028] Lb = La - D (2)

[0029] The two leg blocks 33a and one first gap 4a of the first leg 31a are accommodated in the separation distance La between the flat first joints 32a. Therefore, as shown in the following formula (3), the total length Ba of the leg block 33a is half the value obtained by subtracting the thickness Ga of the first gap 4a from the separation distance La between the first joints 32a.

[0030] Ba = (La - Ga) / 2 (3)

[0031] The two leg blocks 33b and one second gap 4b of the second leg 31b are accommodated in the distance Lb between the protruding second joints 32b. Therefore, as shown in the following formula (4), the total length Bb of the leg block 33b is half the value obtained by subtracting the thickness Gb of the second gap 4b from the distance Lb between the second joints 32b.

[0032] Bb = (Lb - Gb) / 2 (4)

[0033] Since the second joints 32b protrude from the first joints 32a by half the thickness difference D and the second joints 32b face each other, the separation distance Lb is shorter than the separation distance La by the thickness difference D between the first gap 4a and the second gap 4b, as shown in the above formula (2). Then, from the above formulas (2) and (4), the total length Bb of the leg block 33b can be said to be half the value obtained by subtracting the sum of the thickness difference D between the first gap 4a and the second gap 4b and the thickness Gb of the second gap 4b from the separation distance La between the first joints 32a, as shown in the following formula (5).

[0034] Bb = [La - (D + Gb)] / 2 (5)

[0035] As shown in the above formula (1), the sum of the thickness difference D between the first gap 4a and the second gap 4b and the thickness Gb of the second gap 4b is the thickness Ga of the first gap 4a. Therefore, from the above formulas (1) and (5), as shown in the following formula (6), the total length Bb of the leg block 33b can be said to be half the value obtained by subtracting the thickness Ga of the first gap 4a from the separation distance La between the flat first joints 32a.

[0036] Bb = (La - Ga) / 2 (6)

[0037] That is, from the above equations (3) and (6), as shown in the below equation (7), the total length Ba of each leg block 33a of the first leg 31a and the total length Bb of each leg block 33b of the second leg 31b are equal, and the legs can be made to have the same shape and size.

[0038] Ba=Bb (7)

[0039] In this way, in the annular core 3, the height difference between the first joint 32a of the first leg 31a and the second joint 32b of the second leg 31b is the same as half the thickness difference D. Therefore, even if the thickness Ga of the first gap 4a and the thickness Gb of the second gap 4b are different, the annular core 3 can be composed of the leg blocks 33a and 33b of the same shape and size, and the core member of the yoke portion 32 of the same shape and size. That is, the annular core 3 can be composed of a total of two types of core members. The height difference between the first joint 32a and the second joint 32b is the distance between the ends of the first joint 32a and the second joint 32b measured along the direction in which the first leg 31a and the second leg 31b extend.

[0040] Here, the height difference between the first joint 32a of the first leg 31a and the second joint 32b of the second leg 31b may be relative, and is not limited to one-sided protrusion. Fig. 3 is a plan view showing a detailed configuration of the annular core 3 of the second embodiment. As shown in Fig. 3, the first gap 4a of the first leg 31a is thicker than the second gap 4b of the second leg 31b, and when the thickness Gb of the second gap 4b is subtracted from the thickness Ga of the first gap 4a, the first gap 4a and the second gap 4b have a thickness difference D.

[0041] The first joint 32a on the side of the first leg 31a having the thick first gap 4a is recessed from the second joint 32b by half the thickness difference D between the first gap 4a and the second gap 4b. The pair of yoke parts 32 have the same shape and size and are arranged to be symmetrical with respect to a line perpendicular to the extension direction of the first leg 31a and the second leg 31b, and the second joint 32b is arranged to face the second joint 32b of the other yoke part 32. On the other hand, the second joint 32b on the side of the second leg 31b having the thin second gap 4b is flat without protruding or recessing.

[0042] As a result, thick first gaps 4a are interposed between the recessed first joints 32a, but the separation distance La between the first joints 32a is longer than the separation distance Lb between the second joints 32b. The difference between the separation distance La and the separation distance Lb is equal to the thickness difference D between the first gaps 4a and the second gaps 4b. In other words, the thickness difference D between the first gaps 4a and the second gaps 4b is offset by the first joints 32a being recessed and the separation distance La being widened. There is no need to make the leg blocks 33a smaller to accommodate the presence of the thick first gaps 4a.

[0043] Therefore, by recessing the joint 32a, which joins the first leg 31a including the thick first gap 4a, by half the thickness difference D between the first gap 4a and the second gap 4b, and providing a height difference between joints 32a and 32b by half the thickness difference D, the annular core 3 can be constructed from two types of core members: the yoke portion 32 of the same shape and size, and the leg blocks 33a and 33b of the same shape and size.

[0044] Fig. 4 is a plan view showing a detailed configuration of the annular core 3 of the third embodiment. As shown in Fig. 4, the first gap 4a of the first leg 31a is thicker than the second gap 4b of the second leg 31b, and the first gap 4a and the second gap 4b have a thickness difference D. The first joint portion 32a on the first leg 31a side having the thick first gap 4a and the second joint portion 32b on the second leg 31b side having the thin second gap 4b both protrude from the yoke portion 32. This yoke portion 32 has an approximate C-shape or U-shape.

[0045] The pair of yoke portions 32 are of the same shape and size and are arranged to be linearly symmetrical about a line perpendicular to the extension direction of the first leg portion 31a and the second leg portion 31b, with the first joint portions 32a and the second joint portions 32b being arranged opposite each other.

[0046] However, the second joint 32b on the side of the second leg 31b having the thinner second gap 4b has a longer protruding length than the first joint 32a by half the thickness difference D between the first gap 4a and the second gap 4b. In other words, the first joint 32a on the side of the first leg 31a having the thicker first gap 4a has a shorter protruding length than the second joint 32b by half the thickness difference D between the first gap 4a and the second gap 4b, and is recessed by half the thickness difference D with respect to the second joint 32b.

[0047] In this way, by making both the first joint 32a and the second joint 32b protrude and creating a height difference between the first joint 32a and the second joint 32b so that the difference in protrusion length is half the thickness difference D between the first gap 4a and the second gap 4b, it is possible to construct a core member consisting of two types of core members: the yoke portion 32 of the same shape and size, and the leg blocks 33a and 33b of the same shape and size.

[0048] The embodiment in which both the first joint 32a and the second joint 32b are protruding and the difference in protrusion is adjusted is particularly suitable when the yoke portion 32, the leg block 33a, and the leg block 33b are dust cores or metal composite cores. The dust cores or metal composite cores are molded by putting magnetic powder or a mixture of magnetic powder and resin into a mold and compressing it. In press molding using a mold, the dimensions of the yoke portion 32, the leg block 33a, and the leg block 33b are more accurate when both the first joint 32a and the second joint 32b are protruding.

[0049] If the dimensional accuracy of the yoke portion 32, the leg block 33a, and the leg block 33b is poor, the yoke portion 32, the leg block 33a, or the leg block 33b may come off or cracks may occur due to vibration or heat. That is, an unexpected air gap may occur in the annular core 3, and the non-uniformity of the magnetic path may reoccur. However, the embodiment in which both the first joint portion 32a and the second joint portion 32b are protruded can obtain good dimensional accuracy of the yoke portion 32, the leg block 33a, and the leg block 33b in press molding using a mold.

[0050] Fig. 5 is a plan view showing a detailed configuration of the annular core 3 of the fourth embodiment. As shown in Fig. 5, it is necessary to create a small protrusion or recess, but the first joint portion 32a may be recessed and the second joint portion 32b may be protruded. The pair of yoke portions 32 are of the same shape and size and are arranged to be line-symmetrical with respect to a line perpendicular to the extension direction of the first leg portion 31a and the second leg portion 31b, and the first joint portions 32a and the second joint portions 32b are arranged to face each other.

[0051] By recessing first joint portion 32a and protruding second joint portion 32b, the height difference between first joint portion 32a and second joint portion 32b can be adjusted to match the thickness difference D between first gap 4a and second gap 4b. This annular core 3 can also be composed of two types of core members: yoke portion 32 of the same shape and size, and leg blocks 33a and leg blocks 33b of the same shape and size.

[0052] FIG. 6 is a plan view showing a detailed configuration of the annular core 3 of the fifth embodiment. In the annular core 3 of the fifth embodiment, the pair of yoke portions 32 are also of the same shape and size, and are arranged to be symmetrical with respect to a line perpendicular to the extension direction of the first leg portion 31a and the second leg portion 31b, and the first joint portions 32a and the second joint portions 32b are arranged to face each other. Of the first leg portion 31a and the second leg portion 31b, only the first leg portion 31a may be provided with the first gap 4a. In this case, the thickness Gb of the second gap 4b of the second leg portion 31b is considered to be zero. The thickness Ga of the first gap 4a becomes the thickness difference D, and this thickness difference D is absorbed by the height difference between the first joint portion 32a and the second joint portion 32b.

[0053] This annular core 3 can also be composed of two types of core members: a yoke portion 32 having the same shape and size, and leg blocks 33a and 33b having the same shape and size. The second leg 31b can be formed by joining the two leg blocks 33b with an adhesive or the like without inserting the second gap 4b.

[0054] 7 is a plan view showing a detailed configuration of the annular core 3 according to the sixth embodiment. In the annular core 3 according to the sixth embodiment, the pair of yoke portions 32 also have the same shape and size and are arranged to be line-symmetrical with respect to a line perpendicular to the extension direction of the first leg portion 31a and the second leg portion 31b, and the first joint portions 32a and the second joint portions 32b are arranged to face each other.

[0055] Here, if the first gap 4a and the second gap 4b are made thick, there is a risk of magnetic flux leaking from the first gap 4a and the second gap 4b. Depending on the reactor 1, in order to adjust the magnetic flux leakage, a plurality of thin first gaps 4a may be provided in the first leg 31a, and a plurality of thin second gaps 4b may be provided in the second leg 31b.

[0056] The multiple thin first gaps 4a are spaced apart at equal distances along the length of the first leg 31a. This allows the leg blocks 33a aligned with the first leg 31a to have the same shape and size. The multiple thin second gaps 4b are spaced apart at equal distances along the length of the second leg 31b. This allows the leg blocks 33b aligned with the second leg 31b to have the same shape and size.

[0057] The difference between the total thickness Ga of the first gaps 4a and the total thickness Gb of the second gaps 4b is defined as a thickness difference D, and the height difference between the first joint 32a and the second joint 33b is set to half this thickness difference D. As a result, the leg blocks 33a and 33b also have the same shape and size.

[0058] The above has been explained based on the annular core 3 having one ring shape, but an annular core 3 having two or more connected ring shapes can also be formed using two types of core members: a yoke portion 32 of the same shape and size, and leg blocks 33a and 33b of the same shape and size.

[0059] Fig. 8 is a plan view showing the overall configuration of a reactor 1 according to a seventh embodiment. Fig. 9 is a plan view showing the configuration of an annular core 3 according to the seventh embodiment. As shown in Figs. 8 and 9, this reactor 1 includes an annular core 3 having three connected ring shapes and four coils 2.

[0060] The annular core 3 is configured by combining two first legs 31a as center legs, two second legs 31b as outer legs, and a pair of yoke parts 32. The two first legs 31a are arranged next to each other, and the two second legs 31b are arranged separately on both sides of the two first legs 31a. The two first legs 31a and the two second legs 31b are arranged in parallel. A pair of yoke parts 32 is divided and sandwiched between both ends of the first legs 31a and the second legs 31b. The yoke parts 32 are arranged in parallel and extend perpendicular to the extension direction of the first legs 31a and the second legs 31b.

[0061] The pair of yoke parts 32 have second joint parts 32b at both ends in the extension direction, and two first joint parts 32a at the center in the extension direction. The pair of yoke parts 32 have the same shape and size, and are arranged to be symmetrical about a line perpendicular to the extension direction of the first leg part 31a and the second leg part 31b, with the first joint parts 32a and the second joint parts 32b arranged to face each other. The two second joint parts 32b are joined to the two second legs 31b, and the two first joint parts 32a are joined to the two first legs 31a.

[0062] The first leg 31a of the center leg is arranged with leg blocks 33a in series, and a first gap 4a is interposed between the leg blocks 33a. The second leg 31b of the outer leg is arranged with leg blocks 33b in series, and a second gap 4b is interposed between the leg blocks 33b. The thickness Ga of the first gap 4a and the thickness Gb of the second gap 4b are different because the magnetic path lengths of the magnetic flux that flows around them are different.

[0063] In the annular core 3 in which the two ring shapes are connected, a height difference equal to half the thickness difference D between the thickness Ga of the first gap 4a and the thickness Gb of the second gap 4b is provided between the first joint 32a and the second joint 32b. This allows the leg blocks 33b constituting the two second legs 31b that are the outer legs and the leg block 33a constituting the one first leg 31a that is the center leg to have the same shape and size. Therefore, the annular core 3 can be formed by a total of two types of core members, the pair of yoke parts 32 that are the same shape and size, and the leg blocks 33a and 33b that are the same shape and size.

[0064] 10 is a plan view showing the configuration of the annular core 3 according to the eighth embodiment. The annular core 3 has a θ shape in which two ring shapes are connected together, including a first center leg portion 311, a second center leg portion 312, a first outer leg portion 313, and a second outer leg portion 314, and a pair of yoke portions 32. The yoke portion 32 includes a first center leg joint portion 321 that is joined to the first center leg portion 311, a second center leg joint portion 322 that is joined to the second center leg portion 312, a first outer leg joint portion 323 that is joined to the first outer leg portion 313, and a second outer leg joint portion 324 that is joined to the second outer leg portion 314.

[0065] The pair of yoke portions 32 are of the same shape and size, and are arranged so as to be linearly symmetrical about a line perpendicular to the extension direction of the first middle leg portion 311, the second middle leg portion 312, the first outer leg portion 313, and the second outer leg portion 314, and the first middle leg joints 321, the second middle leg joints 322, the first outer leg joints 323, and the second outer leg joints 324 are arranged facing each other.

[0066] The first center leg portion 311 is formed by connecting leg blocks 331, and has a center leg inner gap 41 interposed therebetween. The second center leg portion 312 is formed by connecting leg blocks 332, and has a center leg inner gap 42 interposed therebetween. The first outer leg portion 313 is formed by connecting leg blocks 333, and has a first outer leg inner gap 43 interposed therebetween. The second outer leg portion 314 is formed by connecting leg blocks 334, and has a second outer leg inner gap 44 interposed therebetween. The thickness G1 of the first center leg inner gap 41, the thickness G2 of the second center leg inner gap 42, the thickness G3 of the first outer leg inner gap 43, and the thickness G4 of the second outer leg inner gap 44 are all different values.

[0067] In the case of this annular core 3, one leg is used as a reference. For example, the first middle leg 311 is used as a reference, and the first middle leg 311 is regarded as the first leg 31a, and the first middle leg joint 321 is regarded as the first joint 32a. First, the second middle leg 312 is regarded as the second leg 31b, and the second outer leg joint 322 is regarded as the second joint 32b. The second middle leg joint 322 is protruded or recessed relative to the first middle leg joint 321 so that half of the thickness difference D1 between the thickness G1 of the middle leg gap 41 and the thickness G2 of the second middle leg gap 42 is the height difference between the first middle leg joint 321 and the second middle leg joint 322.

[0068] Next, the first outer leg portion 313 is the second leg portion 31b, and the first outer leg joint portion 323 is the second joint portion 32b. The first outer leg joint portion 323 is protruded or recessed relative to the first middle leg joint portion 321 so that half of the thickness difference D2 between the thickness G1 of the middle leg inner gap 41 and the thickness G3 of the first outer leg inner gap 43 becomes the height difference between the first middle leg joint portion 321 and the first outer leg joint portion 323.

[0069] Next, the second outer leg portion 314 is the second leg portion 31b, and the second outer leg joint portion 324 is the second joint portion 32b. The second outer leg joint portion 324 is protruded or recessed with respect to the first center leg joint portion 321 so that half of the thickness difference D3 between the thickness G1 of the center leg inner gap 41 and the thickness G4 of the second outer leg inner gap 43 is the height difference between the first center leg joint portion 321 and the second outer leg joint portion 324. This allows the leg block 331, the leg block 332, and the leg block 333 to have the same shape and size, and together with the pair of yoke portions 32 having the same shape and size, the annular core 3 can be formed by a total of two types of core members.

[0070] FIG. 11 is a plan view showing the configuration of the annular core 3 according to the ninth embodiment. The coil 2 does not have to be attached to all the legs as in the reactors 1 according to the first to eighth embodiments. The annular core 3 has one ring shape, but the coil 2 is attached only to the first leg 31a, and the coil 2 is not attached to the second leg 31b. Even in this annular core 3, the leg block 33a and the leg block 33b can be made to have the same shape and size by making the height difference between the first joint 32a and the second joint 32b half the thickness difference D between the first gap 4a and the second gap 4b. Together with the pair of yoke parts 32 having the same shape and size, the annular core 3 can be formed by a total of two types of core members.

[0071] As described above, in the reactor 1, the annular core 3 is composed of two or more legs, such as the first leg 31a and the second leg 31b. The first leg 31a and the second leg 31b differ in the presence or absence of a gap, such as the first gap 4a, the total thickness of the first gap 4a and the second gap 4b, or both. In this case, the first joint 32a joined to the first leg 31a and the second joint 32b joined to the second leg 31b have different protruding heights or recessed depths along the extension direction of the first leg 31a and the second leg 31b, and the difference in height is set to be half the difference D in the total thickness of the first gap 4a and the second gap 4b.

[0072] This allows the leg blocks 33a and 33b to have the same shape and size, and together with the pair of yoke portions 32 having the same shape and size, the annular core 3 can be formed using a total of two types of core members. Therefore, even if the thicknesses of the first gap 4a and the second gap 4b are different, the annular core 3 can be formed using a total of two types of yoke portions 32 and a single type of leg block 33a and leg block 33b. This allows a reactor with excellent manufacturing efficiency to be obtained by reducing the number of dies and the probability of incorrect assembly.

[0073] The thickness of the adhesive for bonding the yoke portion 32 to the first leg 31a or the second leg 31b, and the thickness of the adhesive for bonding the leg block 33a or the leg block 33b to the first gap 4a or the second gap 4b may be included in the total thickness Ga of the first gap 4a and the total thickness Gb of the second gap 4b, because the thickness of the adhesive can also function as an air gap.

[0074] In addition, the first joint 32a and the second joint 32b both protrude toward the first leg 31a and the second leg 31b, and the protruding length of the first joint 32a and the protruding length of the second joint 32b are different.

[0075] This allows the protruding lengths of the first and second joints 32a and 32b to approach the designed dimensions with high precision when the yoke 32 is molded using a die, thereby reducing the risk of the yoke 32, leg block 33a, or leg block 33b coming off or cracks occurring due to vibration or heat, causing an unexpected air gap in the annular core 3, and causing the non-uniformity of the magnetic path to reoccur.

[0076] The present invention is not limited to the above-described embodiment, but also includes other embodiments described below. The present invention also includes a combination of all or any of the above-described embodiment and the other embodiments described below. Furthermore, these embodiments can be omitted, replaced, or modified in various ways without departing from the scope of the invention, and such modifications are also included in the present invention.

[0077] For example, the present invention has been described using examples of a single ring-shaped annular core 3 and an annular core 3 made up of three connected ring shapes, but the present invention is not limited to this and can be applied to an annular core 3 made up of multiple legs, such as a θ-shaped annular core 3 having three legs and made up of two connected ring shapes.

[0078] The first gap 4a and the second gap 4b may be formed by stacking multiple extremely thin plates of the same thickness. This allows the first gap 4a and the second gap 4b to be formed by stacking the same parts, further improving production efficiency. The first gap 4a and the second gap 4b may also be provided between the yoke portion 32 and the first leg portion 31a or the second leg portion 31b. [Explanation of symbols]

[0079] 1 Reactor 2 Coil 3. Annular core 31a First leg 31b Second leg 311 First Middle Leg 312 Second Middle Leg 313 First outer leg 314 Second outer leg 32 York 32a First joint 32b Second Joint 321 First mid-leg junction 322 Second mid-leg junction 323 First outer leg joint 324 Second outer leg joint 33a Leg block 33b Leg block 331 Leg Block 332 Leg Block 333 Leg Block 334 Leg Block 4a First Gap 4b The second gap 41 First mid-leg gap 42 Second mid-leg gap 43 First outer leg gap 44 Second outer leg gap

Claims

1. A reactor having an annular core and a coil, The annular core has two or more legs and a pair of yoke portions connecting the legs, The pair of yoke portions are separate from the leg portion and are arranged separately so as to sandwich the leg portion from both ends of the leg portion, one or more of the legs has a gap; The two or more legs include a first leg and a second leg that are different in the presence or absence of the gap or the total thickness of the gap, the yoke portion includes joint portions at which end faces of the leg portions are butted against and joined to the end faces, Each of the joints includes a first joint that is joined to the first leg portion and a second joint that is joined to the second leg portion; The pair of yoke portions are arranged so that the first joint portions face each other via the legs, and the second joint portions face each other via the legs, the first joint portion and the second joint portion of the same yoke portion have different heights along an extension direction of the first leg portion and the second leg portion, based on one of the first joint portion and the second joint portion; a height difference between the first joint portion and the second joint portion is half a difference between a total thickness of the gap of the first leg portion and a total thickness of the gap of the second leg portion; All of the legs are made up of one or more leg blocks connected together, The yoke portions sandwiching the leg portions have the same shape and size, All of the leg blocks of all of the legs have the same shape and size, The annular core is formed of two types of core members, namely, one type of yoke portion and one type of leg block. A reactor characterized by the above.

2. The first joint portion and the second joint portion protrude from the yoke portion toward both legs based on a flat portion between the first leg portion and the second leg portion of the yoke portion, a protruding length of the first joint portion and a protruding length of the second joint portion are different; The reactor according to claim 1 .

3. With respect to a flat portion between the first leg portion and the second leg portion of the yoke portion, only one of the first joint portion and the second joint portion protrudes from the yoke portion or is recessed into the yoke portion, or the first joint portion protrudes from the yoke portion and the second joint portion is recessed into the yoke portion; The reactor according to claim 1 .

4. the annular core has one ring shape having two of the legs, or a shape in which two ring shapes are connected together and have three of the legs; The reactor according to any one of claims 1 to 3,

5. The annular core is a powder magnetic core; The reactor according to any one of claims 1 to 4,

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