JP2025039730A - Reactor - Google Patents

Abstract

A reactor that can be manufactured with excellent efficiency even when the gap thickness is varied is provided.
[Solution] The two or more legs of an annular core 3 of a reactor 1 include a first leg 31a and a second leg 31b which differ in the presence or absence of a gap or in the total thickness of the gap. A first joint 32a of a yoke portion 32 which joins the first leg 31a and a second joint 32b of the yoke portion 32 which joins the second leg 31b have different protruding heights or recessed depths, and the height difference between the first joint 32a and the second joint 32b is half the difference in the total thickness of a first gap 4a and a second gap 4b between the first leg 31a and the second leg 31b.
[Selected figure] Figure 2

Description

The present invention relates to a reactor having a core and a coil.

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.

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 the earth-fault current that flows in the event of an earth-fault in the power system, and arc-suppression reactors to automatically extinguish the arc that occurs when a single-line earth fault occurs in a three-phase power system.

There is a risk of magnetic saturation in reactors, 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 excessive current will flow through the reactor and the circuit in which it 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, suppressing magnetic flux saturation of the reactor.

There is a reactor with a θ-shaped core. The θ-shaped core has a center leg, two outer legs, and a yoke section. Two outer legs are placed on either side of the center leg. The yoke section 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 each of the outer legs and the center leg.

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.

Therefore, to eliminate the difference between the magnetic resistance of the magnetic path passing through the outer leg and the magnetic path passing 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 (see, for example, 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.

There is also a reactor with a ring-shaped core. The core of this reactor has a ring shape with two legs sandwiched between yoke parts on both sides. Even in a reactor with a 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 in the magnetic path will also occur.

JP 2018-26504 A

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

In this way, if 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 material. If 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 material.

Therefore, when the gap thickness is made different, at least three or more types of molds and manufacturing equipment are required to produce the yoke portion and two or more types of leg blocks. This reduces the manufacturing efficiency of the reactor compared to a reactor with a uniform gap. There is also a risk of misassembly of the two types of leg blocks, which reduces the yield and also reduces the manufacturing efficiency of the reactor.

The present invention was made to solve the above problems, and its purpose is to provide a reactor that has excellent manufacturing efficiency even when the gap thickness is changed.

The reactor of the present invention is a reactor having an annular core and a coil, the annular core having two or more legs and a pair of yokes connecting the legs, one or more of the legs having a gap, the two or more legs including a first leg and a second leg that differ in the presence or absence of the gap or the total thickness of the gap, the yoke has each joint that joins to the end surface of the leg, each joint includes a first joint that joins to the first leg and a second joint that 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 height difference 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.

According to the present invention, even if the gap thickness is different, the core is made of one type of yoke portion and one type of leg block, resulting in a reactor with excellent manufacturing efficiency.

1 is a plan view showing an overall configuration of a reactor according to a first embodiment. FIG. FIG. 2 is a plan view showing the configuration of an annular core according to the first embodiment. FIG. 11 is a plan view showing the configuration of an annular core according to a second embodiment. FIG. 11 is a plan view showing the configuration of an annular core according to a third embodiment. FIG. 10 is a plan view showing the configuration of an annular core according to a fourth embodiment. FIG. 13 is a plan view showing the configuration of an annular core according to a fifth embodiment. FIG. 13 is a plan view showing the configuration of an annular core according to a sixth embodiment. FIG. 13 is a plan view showing an overall configuration of a reactor according to a seventh embodiment. FIG. 13 is a plan view showing the configuration of an annular core according to a seventh embodiment. FIG. 13 is a plan view showing an overall configuration of a reactor according to an eighth embodiment. FIG. 13 is a plan view showing the configuration of an annular core according to a ninth embodiment.

The reactors of the various embodiments of the present invention will be described below with reference to the drawings. In the drawings, thicknesses, dimensions, positional relationships, ratios, shapes, etc. may be emphasized for ease of understanding, but the present invention is not limited to such emphasis.

Figure 1 shows the overall configuration of a reactor according to the first embodiment. This reactor 1 has two coils 2 and one annular core 3. The two coils 2 are attached to the annular core 3. Current is passed through the coils 2, which generate 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 coils 2 according to a magnetic permeability higher than that of a vacuum. In other words, the reactor 1 is a passive element that converts electrical energy into magnetic energy and stores and releases it.

The coil 2 is a cylindrically wound body made of conductive wire such as copper wire. This 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.

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. A dust core is a compact made by compressing magnetic powder and then annealing it. Magnetic powders are mainly composed of iron, and examples of such powders 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, or a mixture of two or more of these powders. A metal composite core is a core made by kneading and molding magnetic powder and resin.

Figure 2 is a plan view showing the detailed configuration of the annular core 3 of the first embodiment. As shown in Figure 2, the annular core 3 has a first leg 31a, a second leg 31b, and a pair of yoke portions 32. The first leg 31a, the second leg 31b, and the pair of yoke portions 32 are combined to form the annular core 3, which is a ring-shaped closed magnetic circuit. The first leg 31a and the second leg 31b are fitted into the coil 2 and are magnetic flux generating portions that generate magnetic flux. The yoke portion 32 is a connecting portion that connects the first leg 31a and the second leg 31b with magnetic flux.

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 with the first leg 31a and a second joint part 32b that joins with 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. This causes the annular core 3 to form a closed ring shape.

The first leg 31a is made up of two leg blocks 33a connected together. A first gap 4a is interposed between the two leg blocks 33a. The second leg 31b is made up of 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 in the center of the length of the first leg 31a and the second leg 31b. The total lengths Ba of the leg blocks 33a on both sides of the first gap 4a are the same. The total lengths Bb of the leg blocks 33b on both sides of the second gap 4b are the same.

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. An air gap is a gap without a magnetic material.

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.

D=Ga-Gb...(1)

The pair of yoke parts 32 are of the same shape and size, and are arranged so as to be symmetrical about a line perpendicular to the extension direction of the first leg part 31a and the second leg part 31b. The second joint part 32b on the second leg part 31b side 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 direction in which the second leg part 31b extends. On the other hand, the first joint part 32a on the first leg part 31a side 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.

Lb=La-D...(2)

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.

Ba=(La-Ga)/2...(3)

The two leg blocks 33b and one second gap 4b of the second leg 31b are accommodated within 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.

Bb=(Lb-Gb)/2...(4)

Because 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).

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

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 this 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.

Bb=(La-Ga)/2...(6)

In other words, from the above formulas (3) and (6), as shown in the following formula (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 blocks can be made to have the same shape and size.

Ba=Bb...(7)

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 core members of the leg blocks 33a and 33b of the same shape and size, and the yoke portion 32 of the same shape and size. In other words, 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.

Here, the height difference between the first joint 32a of the first leg 31a and the second joint 32b of the second leg 31b only needs to be relative, and is not limited to one protruding from the other. 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.

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 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 31a and the second leg 31b, and the second joint 32b is arranged opposite 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.

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 gap 4a and the second gap 4b. In other words, the thickness difference D between the first gap 4a and the second gap 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 block 33a smaller to accommodate the presence of the thick first gap 4a.

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 creating 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 32 of the same shape and size, and the leg blocks 33a and 33b of the same shape and size.

Figure 4 is a plan view showing the detailed configuration of the annular core 3 of the third embodiment. As shown in Figure 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 32a on the first leg 31a side having the thick first gap 4a and the second joint 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.

The pair of yoke parts 32 are 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 leg part 31a and the second leg part 31b, with the first joint parts 32a and the second joint parts 32b arranged opposite each other.

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.

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 protruding length is half the thickness difference D between the first gap 4a and the second gap 4b, it is possible to configure a total 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.

The mode of protruding both the first joint 32a and the second joint 32b and adjusting the protrusion difference is particularly suitable when the yoke portion 32, the leg block 33a, and the leg block 33b are dust cores or metal composite cores. Dust cores or metal composite cores are molded by placing magnetic powder or a mixture of magnetic powder and resin in 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.

If the dimensional accuracy of the yoke portion 32, leg block 33a, and leg block 33b is poor, there is a risk that the yoke portion 32, leg block 33a, or leg block 33b may come off or cracks may occur due to vibration or heat. In other words, there is a risk that an unexpected air gap may occur in the annular core 3, and the non-uniformity of the magnetic path may reoccur. However, the mode in which both the first joint portion 32a and the second joint portion 32b are protruding can obtain good dimensional accuracy of the yoke portion 32, leg block 33a, and leg block 33b during press molding using a mold.

Figure 5 is a plan view showing the detailed configuration of the annular core 3 of the fourth embodiment. As shown in Figure 5, it is necessary to create small protrusions and recesses, but the first joint 32a may be recessed and the second joint 32b may be protruded. The pair of yoke parts 32 are of the same shape and size and are arranged to be linearly symmetrical with respect to a line perpendicular to the extension direction of the first leg 31a and the second leg 31b, with the first joints 32a and the second joints 32b arranged opposite each other.

By recessing the first joint 32a and protruding the second joint 32b, the height difference between the first joint 32a and the second joint 32b can be adjusted to match the thickness difference D between the first gap 4a and the second gap 4b. This annular core 3 can also be constructed from 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.

Figure 6 is a plan view showing the 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 about a line perpendicular to the extension direction of the first leg 31a and the second leg 31b, and the first joints 32a and the second joints 32b are arranged opposite each other. Of the first leg 31a and the second leg 31b, only the first leg 31a may be provided with the first gap 4a. In this case, the thickness Gb of the second gap 4b of the second leg 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 32a and the second joint 32b.

This annular core 3 can also be constructed from 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. The second leg 31b can be formed by joining the two leg blocks 33b with an adhesive or the like without inserting a second gap 4b.

Figure 7 is a plan view showing the detailed configuration of the annular core 3 of the sixth embodiment. In the annular core 3 of the sixth embodiment, the pair of yoke portions 32 are also 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 leg portion 31a and the second leg portion 31b, with the first joint portions 32a and the second joint portions 32b arranged opposite each other.

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, multiple thin first gaps 4a may be provided in the first leg 31a, and multiple thin second gaps 4b may be provided in the second leg 31b.

The multiple thin first gaps 4a are spaced apart at equal distances along the length of the first leg 31a. This ensures that the leg blocks 33a aligned with the first leg 31a are of 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 ensures that the leg blocks 33b aligned with the second leg 31b are of the same shape and size.

The difference between the total thickness Ga of the first gaps 4a (EGa) and the total thickness Gb of the second gaps 4b (EGb) is taken as the thickness difference D, and the height difference between the first joint 32a and the second joint 33b is taken as half of this thickness difference D. This makes the leg block 33a and the leg block 33b the same shape and size.

The above explanation has been based on an annular core 3 having one ring shape, but an annular core 3 having two or more ring shapes connected together 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.

Figure 8 is a plan view showing the overall configuration of a reactor 1 according to the seventh embodiment. Figure 9 is a plan view showing the configuration of an annular core 3 according to the seventh embodiment. As shown in Figures 8 and 9, this reactor 1 has an annular core 3 with three connected ring shapes and four coils 2.

This annular core 3 is composed of two first legs 31a as middle legs, two second legs 31b as outer legs, and a pair of yoke parts 32. The two first legs 31a are arranged side by side, 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 are separated 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.

The pair of yoke parts 32 have second joints 32b at both ends in the extension direction, and two first joints 32a at the center in the extension direction. The pair of yoke parts 32 are 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 leg part 31a and the second leg part 31b, with the first joints 32a and the second joints 32b arranged opposite each other. The two second joints 32b are joined to the two second legs 31b, and the two first joints 32a are joined to the two first legs 31a.

The first leg 31a of the middle leg is arranged with leg blocks 33a in a row, with a first gap 4a between the leg blocks 33a. The second leg 31b of the outer leg is arranged with leg blocks 33b in a row, with a second gap 4b 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.

Even in this annular core 3 in which 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 middle leg to be the same shape and size. Therefore, the annular core 3 can be formed from a total of two types of core members: a pair of yoke parts 32 of the same shape and size, and leg blocks 33a and 33b of the same shape and size.

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

The pair of yoke parts 32 are the same shape and size, and are arranged so as to be symmetrical about a line perpendicular to the extension direction of the first middle leg part 311, the second middle leg part 312, the first outer leg part 313, and the second outer leg part 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 opposite each other.

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

In the case of this annular core 3, one leg is used as the reference. For example, the first middle leg 311 is used as the 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.

Next, the first outer leg 313 is the second leg 31b, and the first outer leg joint 323 is the second joint 32b. The first outer leg joint 323 is protruded or recessed relative to the first middle leg joint 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 is the height difference between the first middle leg joint 321 and the first outer leg joint 323.

Next, the second outer leg 314 is the second leg 31b, and the second outer leg joint 324 is the second joint 32b. The second outer leg joint 324 is protruded or recessed relative to the first middle leg joint 321 so that half of the thickness difference D3 between the thickness G1 of the middle leg inner gap 41 and the thickness G4 of the second outer leg inner gap 43 is the height difference between the first middle leg joint 321 and the second outer leg joint 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 a pair of yoke portions 32 of the same shape and size, the annular core 3 can be formed using a total of two types of core members.

Figure 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 legs as in the reactors 1 of the first to eighth embodiments. This annular core 3 has a single 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 with this annular core 3, the leg block 33a and the leg block 33b can be made 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 of the same shape and size, the annular core 3 can be formed from a total of two types of core members.

As described above, the annular core 3 in the reactor 1 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 that joins the first leg 31a and the second joint 32b that joins 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 height difference is set to be half the total thickness difference D of the first gap 4a and the second gap 4b.

This allows the leg blocks 33a and 33b to be made of the same shape and size, and together with a pair of yoke portions 32 of the same shape and size, the annular core 3 can be formed from a total of two types of core material. Therefore, even if the thicknesses of the first gap 4a and the second gap 4b are different, the annular core 3 can be formed from a total of two types: one type of yoke portion 32 and one type of leg block 33a and leg block 33b. This allows for a reactor with excellent manufacturing efficiency to be obtained by reducing the number of molds and the probability of assembly errors.

The thickness of the adhesive used to join the yoke portion 32 to the first leg 31a or the second leg 31b, and the thickness of the adhesive used to join 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. This is because the thickness of the adhesive can also function as an air gap.

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.

As a result, when the yoke portion 32 is molded using a mold, the protruding length of the first joint portion 32a and the protruding length of the second joint portion 32b can be made to approach the design dimensions with high precision. This reduces the risk of the yoke portion 32, leg block 33a, or leg block 33b coming off or cracking 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.

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, various omissions, substitutions, and modifications can be made to these embodiments without departing from the scope of the invention, and such modifications are also included in the present invention.

For example, the above description uses an annular core 3 with one ring shape and an annular core 3 with three ring shapes connected together, but the present invention is not limited to this and can be applied to an annular core 3 with multiple legs, such as a θ-shaped annular core 3 with three legs and two ring shapes connected together.

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 constructed 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.

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 Yoke 32a First joint 32b Second joint 321 First middle leg joint 322 Second middle leg joint 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 Second gap 41 First middle leg inner gap 42 Second middle leg inner gap 43 First outer leg inner gap 44 Second outer leg inner gap

Claims (5)

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

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