Reactor

Abstract

To provide a reactor that does not require a slide mold that can be moved away from the end face of a core block.SOLUTION: A core 1 of a reactor 10 is formed by arranging the end faces of a core block 3 coated with a core covering resin 4 such that the end faces face each other. The core covering resin 4 has a resin end surface 41 covering a first block end surface 31 of the core block 3. A notch 5 is formed in the resin end surface 41. The notch 5 extends from the center of the resin end surface 41 toward the surface edge by cutting the surface edge, exposes the first block end surface 31 of the core block 3, and has an opening 51 on a resin side surface 42 orthogonal to the resin end surface 41.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a reactor including a core and a coil.

Background Art

[0002] A reactor mainly consists of a coil and a core. The coil generates magnetic flux according to the number of turns when energized. The core forms a closed magnetic path that conducts the magnetic flux generated by the coil according to a magnetic permeability higher than that of vacuum. That is, a reactor is an electromagnetic component that converts electrical energy into magnetic energy for storage and release.

[0003] Such reactors are used in a wide variety of applications. Representative reactors include step-up reactors, series reactors, parallel reactors, current-limiting reactors, starting reactors, shunt reactors, neutral point reactors, and arc-extinguishing reactors, etc.

[0004] The step-up reactor is incorporated into an in-vehicle step-up circuit such as a drive system of a hybrid vehicle or an electric vehicle. The series reactor is connected in series to an electric motor circuit to limit the current during a short circuit. The parallel reactor stabilizes the current sharing between parallel circuits. The current-limiting reactor limits the current during a short circuit and is connected thereto. The starting reactor is connected in series to an electric motor circuit that protects a machine to limit the starting current. The shunt reactor is connected in parallel to a transmission line to compensate for leading reactive power and suppress abnormal voltage. The neutral point reactor is connected between the neutral point and the ground and is used to limit the ground fault current flowing during a ground fault accident in the power system. The arc-extinguishing reactor automatically extinguishes the arc generated during a single-phase ground fault in a three-phase power system.

[0005] The core is formed by connecting a plurality of core blocks annularly. Each core block may be individually covered with core coating resin by being molded with resin (see, for example, Patent Document 1). When molding the core block with resin, it is planned to bring both end faces of the core block into contact with the mold.

[0006] However, due to manufacturing errors in the core block, there is a risk that the end face of the core block may not reach the mold slightly. If the end face of the core block does not reach the mold, resin pieces, so-called burrs, will be generated on the end face of the core block at locations where resin coating was not planned. When this burr occurs, a manufacturing process for removing the burr must be added, resulting in an increase in manufacturing man-hours.

[0007] Therefore, a reactor in which the end face of the core block is also covered with core coating resin has been proposed (see, for example, Patent Document 2). If the end face of the core block is also covered with resin and the thickness of the resin covering the end face is designed in advance as a gap, the process of removing burrs itself becomes unnecessary. By reducing the exposure of the core block, an effect of reducing noise due to magnetostriction of the core also occurs.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] When molding a core block with resin, in order to hold the core block in the mold, it is not possible to completely mold the entire end face of the core block with resin, and contact points supported by the mold are required on a part of the end face of the core block. Holes are formed in the core coating resin at these contact points.

[0010] Since this hole portion has an undercut, as a mold for molding the core block with resin, at least three types of molds are required: an upper mold facing a single side surface orthogonal to the end surface of the core block, a lower mold positioned opposite to the upper mold, and a movable slide mold movable in a direction away from the end surface of the core block. Therefore, the manufacturing cost of the reactor increases, and the mold becomes complicated, which may lead to an increase in manufacturing errors of the reactor and a deterioration in yield.

[0011] The present invention has been proposed to solve the above problems, and an object thereof is to provide a reactor that does not require a movable slide mold movable in a direction away from the end surface of the core block.

Means for Solving the Problems

[0012] To achieve the above object, a reactor according to an embodiment of the present invention includes a plurality of core blocks, a plurality of core coating resins that individually coat each of the core blocks, a core that combines the core blocks coated with the core coating resins to form an annular closed magnetic circuit, and a coil mounted on the core block from above the core coating resin. The core coating resin has a resin end surface that coats the end surface of the core block. In the resin end surface, a notch is formed that extends from the center side of the surface of the resin end surface toward the edge of the surface, cutting off the edge of the surface, exposing the end surface of the core block, and having an opening in a resin side surface orthogonal to the resin end surface.

[0013] The core coating resin may have a hole portion that exposes the core block at a position directly opposite to the notch in a direction orthogonal to the resin end surface.

[0014] The reactor may include a second resin that integrally coats the coil and the core, and the second resin may flow from the opening into the notch and solidify.

[0015] The notch may have a tapered shape that gradually widens from the center side of the surface of the resin end surface toward the edge of the surface.

[0016] The core coating resin may cover one end face of the core block with the resin end face having the notch, cover the side face of the core block until it is flush with the other end face of the core block, and expose the entire area of the other end face.

[0017] The core block may be a single continuous block without joints, a composite in which smaller blocks are connected in series, or a composite in which gaps are interposed between smaller blocks.

Advantages of the Invention

[0018] According to the present invention, the mold can be removed from the center side of the resin end face of the core coating resin toward the edge of the face, and a movable slide mold in a direction away from the end face of the core block becomes unnecessary.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0020] Hereinafter, with reference to the drawings, the reactor according to the embodiment of the present invention will be described. In each drawing, for ease of understanding, the thickness, dimensions, positional relationship, ratio, shape, etc. may be emphasized and shown, and the present invention is not limited to those emphasized.

[0021] FIG. 1 is a perspective view showing the main configuration of the reactor of the present embodiment. For convenience of explanation, the members covering each part are omitted. The reactor 10 includes one annular core 1 and two coils 2, 2. The two coils 2, 2 are horizontally arranged and fitted on one core 1. These coils 2, 2 generate magnetic flux according to the number of turns when energized. The core 1 forms a closed magnetic circuit that passes the magnetic flux generated by the coils 2, 2 according to a magnetic permeability higher than that of a vacuum. That is, this reactor 10 is an electromagnetic component that converts electrical energy into magnetic energy for storage and release.

[0022] The two coils 2, 2 are formed as a connected coil that is separately wound without separating two separated positions in one conductive wire 21 such as a copper wire. Each coil 2 is formed by winding the conductive wire 21 in a spiral shape while shifting the winding position by one turn along the winding axis. The axes of the two coils 2, 2 are parallel, and the two coils 2, 2 are arranged side by side so that the directions of the currents flowing through the two coils 2, 2 are opposite to each other. When the two coils 2 are arranged side by side, the winding directions of the two coils 2, 2 are the same.

[0023] The wire material at the end of the one conductive wire 21 that is more distant from the coils 2, 2 is drawn out from one end face of each coil 2. The drawn conductive wire 21 is connected to an electric circuit, enabling the coil 2 to be energized. Also, the wire material between the coils 2, 2 in the one conductive wire 21 forms a connecting wire 22 that connects the two coils 2, 2.

[0024] FIG. 2 is a perspective view of core 1, and FIG. 3 is an exploded view of core 1. Core 1 is formed by connecting core blocks 3 in a ring shape. Each core block 3 has various shapes such as U-shaped, linear, J-shaped, or E-shaped. For example, two U-shaped core blocks 3 can be opposed and combined, two J-shaped core blocks 3 can be arranged and combined in a point-symmetrical relationship, two E-shaped core blocks 3 can be opposed and combined, or a linear shape can be included between a set of U-shaped, J-shaped, or E-shaped core blocks 3 for combination, and they are connected in a ring shape.

[0025] Each core block 3 is a magnetic body integrally molded without joints, a composite in which smaller magnetic body blocks are connected by an adhesive or the like, or a composite in which a gap is inserted between smaller magnetic body blocks. The magnetic body is, for example, a compacted powder core, a ferrite core, a metal composite core, or a laminated steel sheet. The compacted powder core is formed by annealing a compacted powder body of magnetic powder. The magnetic powder has iron as the main component, and examples include pure iron powder, permalloy (Fe-Ni alloy) with iron as the main component, Si-containing iron alloy (Fe-Si alloy), sendust alloy (Fe-Si-Al alloy), amorphous alloy, nanocrystalline alloy powder, or a mixed powder of two or more of these powders. The metal composite core is formed by kneading and molding magnetic powder and resin.

[0026] Each core block 3 is individually coated with a core coating resin 4 to be electrically insulated from the coil 2 and then connected in a ring shape. The core coating resin 4 is a molded product that maintains a certain shape and has insulation and heat resistance. Examples of the material of the core coating resin 4 include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), PBT (Polybutylene Terephthalate), or a composite thereof, and a heat-conductive filler may be mixed in.

[0027] This core coating resin 4 is molded to cover the core block 3 by individually accommodating the core block 3 in a mold and injecting the resin. Each core coating resin 4 covers not only the side periphery of the core block 3 in the mold but also the first block end face 31 which is one end face through which the magnetic flux of the core block 3 passes. In other words, each core coating resin 4 includes not only a resin side face 42 that covers the side periphery of the core block 3 but also a resin end face 41 that covers the first block end face 31.

[0028] The second block end face 32 which is the other end face through which the magnetic flux of the core block 3 passes is exposed from the core coating resin 4. This exposure is formed by the resin side face 42 extending until it is flush with the second block end face 32 of the core block 3. On the other hand, the resin end face 41 continuously covers the first block end face 31 of the core block 3 without a joint with the resin side face 42.

[0029] When connecting two core blocks 3 covered with the core coating resin 4, an annular core 1 is formed by connecting the resin end face 41 of the core coating resin 4 covering one core block 3 and the second block end face 32 exposed from the core coating resin 4 of the other core block 3. Therefore, the resin end face 41 covering the first block end face 31 of the core block 3 closely adheres to and covers the second block end face 32 of the core block 3.

[0030] FIG. 4 is a perspective view of the end face side of the core coating resin 4. As shown in FIG. 4, a notch 5 is formed in this resin end face 41. The notch 5 is a rectangular hole extending from the center side of the face of the resin end face 41 towards the face edge, cutting off the face edge. The notch 5 penetrates the front and back of the resin end face 41 and exposes a part of the first block end face 31 of the core block 3. Since the notch 5 cuts off the face edge of one side of the resin end face 41, an opening 51 connected to the inside of the notch 5 is provided in the resin side face 42 adjacent to the resin end face 41 with the cut-off face edge as a boundary.

[0031] FIG. 5 is a rear perspective view of the core coating resin 4. When the core block 3 is U-shaped or J-shaped, the core coating resin 4 has a resin back surface 43 which is the surface opposite to the resin end surface 41. The resin back surface 43 covers the yoke portion of the U-shaped or J-shaped core block 3. In this resin back surface 43, a hole 6 opens at a position exactly opposite to the notch 5 in a direction orthogonal to the resin end surface 41, and the core block 3 is exposed.

[0032] FIG. 6 is a diagram showing the process of mold molding of the core coating resin 4 having such a shape, (a) shows the time of injection molding, and (b) shows the time of demolding. This FIG. 6 shows the process of mold molding by a plan view seen from a direction in which the U-shaped core block 3 is orthogonal to the resin end surface 41 and the core block 3 is projected in a rectangular shape.

[0033] As shown in FIG. 6(a), the core block 3 is accommodated in a sealed space defined by the lower mold K1, the upper mold K2, and the block back surface support mold K3. The lower mold K1 supports the surface on which the U-shape of the U-shaped core block 3 appears, and the upper mold K2 is in pressure contact with the core block 3 from a position opposite to the lower mold K1. The block back surface support mold K3 slides in a contactable and separable manner toward the position and range where the hole 6 of the core block 3 is formed and is in pressure contact.

[0034] The lower mold K1 includes a first block end surface support piece K11. The first block end surface support piece K11 is in pressure contact with the first block end surface 31 of the core block 3 at the position and range of the notch 5. The block back surface support mold K3 extends at a position opposite to the first block end surface support piece K11 and is in pressure contact with the core block 3 at the position and range of the hole 6. The core block 3 is clamped by the first block end surface support piece K11 and the block back surface support mold K3.

[0035] The upper and lower mold K1 also has a support piece that presses against the entire surface of the second block end face 32. The support piece that presses against the second block end face 32 may be provided on the upper mold K2 side. Further, the lower mold K1 further supports the core block 3 from below and is also supported from below by an extrusion pin for separating the core block 3 on which the core coating resin 4 is formed from the lower mold 1.

[0036] As shown in FIG. 6(b), when resin is injected into the mold and the core coating resin 4 is formed on the core block 3, the lower mold K1, the upper mold K2, and the block back support mold K3 are separated. Since the notch 5 is not an undercut surrounded by resin on all sides, the core block 3 with the core coating resin 4 formed thereon can be pushed out from the lower mold K1 along the direction in which the first block end face support piece K11 extends.

[0037] In this way, since the notch 5 extends so as to cut the surface edge from the center side of the surface toward the surface edge, it does not become an undercut. Therefore, the first block end face support piece K11 that supports the first block end face 31 can be extended from the lower mold K1. Then, in the process of forming the core coating resin 4, it is not necessary to separately prepare a slide mold that contacts and separates in a direction orthogonal to the first block end face 31.

[0038] FIG. 7 is a perspective view showing the reactor 10 on which the second resin 8 is formed. As shown in FIG. 7, the core 1 and the coil 2 in which the core blocks 3 coated with the core coating resin 4 are connected are molded and integrated by the second resin 8. This second resin 8 is also a molded product that retains a certain shape, like the core coating resin 4, and has insulation and heat resistance.

[0039] Examples of the material of the second resin 8 include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), PBT (Polybutylene Terephthalate), or a composite thereof, and a thermally conductive filler may be incorporated. Note that the core coating resin 4 and the second resin 8 may be made of different materials.

[0040] FIG. 8 is a perspective view showing the core coating resin 4 when the second resin 8 is injection-molded. In FIG. 8, for convenience of explanation, the adjacent core coating resin 4 is omitted, but the resin end face 41 in which the notch 5 is formed is connected over the entire area to the second block end face 32 of the core block 3 covered with the other core coating resin 4, and the notch 5 is closed from a direction orthogonal to the resin end face 41.

[0041] However, the notch 5 extends by cutting off the surface edge from the center side of the surface of the resin end face 41 toward the surface edge. Therefore, an opening 51 communicating with the notch 5 is generated in the resin side face 42 continuous with the resin end face 41 with the surface edge cut off by the notch 5 as a boundary. Therefore, when the second resin 8 is also filled in the space between the inner peripheral surface and the outer surface of the core 1, the second resin 8 flows in from the opening 51 and is also filled in the notch 5 and solidifies. Further, when the first block end face 31 is pressed by the other core coating resin 4, air easily escapes from the opening 51. Therefore, air escapes from the inside of the notch 5, and the inside of the notch 5 becomes solid with the second resin 8.

[0042] If air remains in the notch 5, heat accumulates in the notch 5 due to the low thermal conductivity of air. However, since the notch 5 is filled with the second resin 8, the heat in the notch 5 can be released.

[0043] As described above, the reactor 10 includes a plurality of core blocks 3, a plurality of core coating resins 4 that individually coat each of the core blocks 3, a core 1 that combines the core blocks 3 coated with the core coating resins 4 to form an annular closed magnetic circuit, and a coil 2 that is mounted on the core blocks 3 from above the core coating resins 4. The core coating resin 4 has a resin end face 41 that coats the first block end face 31 of the core block 3. A notch 5 is formed in the resin end face 41. The notch 5 extends from the center side of the resin end face 41 toward the edge of the face, cutting off the edge of the face, exposing the first block end face 31 of the core block 3, and having an opening 51 in a resin side face 42 orthogonal to the resin end face 41.

[0044] Thereby, when the core coating resin 4 is injection-molded, the notch 5 does not become an undercut, and a first block end face support piece K11 that supports the first block end face 31 of the core block 3 can be extended from the lower mold K1. Therefore, even if the first block end face 31 is coated with the resin end face 41, it is not necessary to prepare a slide mold or the like, and the reactor 10 can be manufactured at low cost and with high precision.

[0045] Further, the core coating resin 4 has a hole portion 6 that exposes the core block 3 at a position directly opposite to the notch 5 in a direction orthogonal to the resin end face 41. Thereby, the core block 3 can be stably installed in the mold against the injection pressure of the core coating resin 4, and the core block 3 can be accurately coated with the core coating resin 4.

[0046] Further, a second resin 8 that integrally coats the coil 2 and the core 1 is provided, and the second resin 8 is made to flow into the notch 5 from the opening 51 and solidify. Thereby, no air remains in the notch 5, and the thermal conductivity in the notch 5 can be increased.

[0047] Furthermore, this embodiment is presented as an example and is not limited to the above embodiment. The above embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. And the embodiments and their modifications are included in the scope of the present invention.

[0048] For example, if there is a notch 5, even if the two coils 2, 2 are not connected coils but are separately manufactured and attached to the reactor 10, the cost of the mold can be reduced, the mold can be made less complicated, and the reactor 10 can be manufactured inexpensively and with high precision. Also, three or more coils 2, 2, 2 may be arranged side by side and attached to one core 1.

[0049] The notch 5 may have a tapered shape that gradually widens from the center side of the resin end face 41 toward the edge of the face. Since the tapered shape guides the second resin 8 into the notch 5, it becomes easier to suppress the second resin 8 from flowing sufficiently into the notch 5 and leaving a void in the notch 5. Incidentally, the second resin 8 may be an injection molding resin obtained by accommodating an assembly composed of a core block 3 covered with the core coating resin 4 and the coil 2 in a mold, or may be a filler that fills the case when the reactor 10 is provided with a case and the assembly is accommodated in the case.

[0050] The first block end face 31 is configured such that the first block end face support piece K11 provided in the lower mold K1 is provided in the mold. Not limited to this, the first block end face support piece K11 may be provided in the upper mold K2. When the first block end face support piece K11 is provided in the upper mold K2, the notch 5 extends from the center side of the first block end face 31 toward the edge of the upper mold K2 side and cuts this edge.

[0051] Preferably, the first block end face support piece K11 is provided on the lower mold K1, and the notch 5 extends from the center side of the face of the first block end face 31 toward the face edge on the lower mold K1 side and is formed to cut off this face edge. When forming the notch 5 extending toward the lower mold K1 side, the alignment between the first block end face support piece K11 and the first block end face 31 can be completed simultaneously with the installation of the core block 3 on the lower mold K1. On the other hand, when the first block end face support piece K11 is provided on the upper mold K2, when closing the upper mold K2 and the lower mold K1, since the first block end face support piece K11 descends toward the core block 3, it is necessary to adjust the positions of the lower mold K1 and the core block 3 in advance so that the first block end face support piece K11 does not collide with the core block 3. Therefore, providing the first block end face support piece K11 on the lower mold K1 improves the productivity of the reactor 10 compared to the case of providing it on the upper mold K2.

[0052] In the present embodiment, as an example, a single resin end face 41 is sandwiched between adjacent core blocks 3. To realize this aspect, the first block end face 31 covered with the resin end face 41 of one of the core blocks 3 and the exposed second block end face 32 of the other core block 3 are made to face each other. In addition to this, in order to sandwich a single resin end face 41 between adjacent core blocks 3, both end faces of one core block 3 may be covered with the resin end face 41, notches 5 may be formed in the resin end faces 41 of both end faces, and both end faces of the other core block 3 may be exposed.

[0053] That is, not all of the core coating resins 4 that cover all of the core blocks 3 necessarily have resin end faces 41. The reactor 10 may include two types of core coating resins 4, one having resin end faces 41 at both ends and the other exposing the core blocks 3 from both ends. For example, the core 1 is composed of a combination of two U-shaped core blocks 3. The core coating resin 4 that covers one of the U-shaped core blocks 3 has resin end faces 41 at both end faces. Notches 5 are formed in the resin end faces 41 of both end faces, respectively. The core coating resin 4 that covers the other U-shaped core block 3 exposes the entire area of both end faces of the core block 3. When these U-shaped core blocks 3 are arranged opposite to each other, a single resin end face 41 is sandwiched between adjacent core blocks 3.

Explanation of Signs

[0054] 1 Core 2 Coil 21 Conductive wire 22 Connecting wire 3 Core block 31 First block end face 32 Second block end face 4 Core coating resin 41 Resin end face 42 Resin side face 43 Resin back face 5 Notch 51 Opening 6 Hole portion 8 Second resin 10 Reactor K1 Lower mold K11 First block end face support piece K2 Upper mold K3 Block back face support mold

Claims

1. A plurality of core blocks, a plurality of core coating resins that individually coat each of the core blocks, a core that combines the core blocks coated with the core coating resins to form an annular closed magnetic circuit, a coil mounted on the core blocks from above the core coating resins, comprising: the core coating resin has a resin end face that coats the end face of the core block, the end face of the core block is a face that approaches an adjacent core block when the annular closed magnetic circuit is formed, a notch is formed in the resin end face that extends from the center side of the face of the resin end face toward the face edge, cutting off the face edge, exposing the end face of the core block, and having an opening in a resin side face orthogonal to the resin end face, a reactor characterized by the above.

2. the core coating resin has a hole that exposes the core block at a position directly opposite to the notch in a direction orthogonal to the resin end face, the reactor according to Claim 1, characterized by the above.

3. comprising a second resin that integrally coats the coil and the core, the second resin flows in from the opening into the notch and is solidified, the reactor according to Claim 1 or 2, characterized by the above.

4. the notch has a tapered shape that gradually widens from the center side of the face of the resin end face toward the face edge, the reactor according to Claim 3, characterized by the above.

5. the core coating resin covers one end face of the core block with the resin end face having the notch, covers the side face of the core block until it is flush with the other end face of the core block, exposing the entire other end face, the reactor according to any one of Claims 1 to 4, characterized by the above.

6. the core block is a single block that is continuously connected without joints, a composite body in which smaller blocks are connected in series, or a composite body in which a gap is interposed between smaller blocks, the reactor according to any one of Claims 1 to 5, characterized by the above.

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