Molded coil and reactor

Abstract

To provide a molded coil and a reactor that are excellent in heat dissipation properties by restraining resin leakage to an opening surface.SOLUTION: A molded coil 1 includes a coil coating resin 3 that coats a part or all of a coil 2. The coil coating resin 3 includes an end face plate 71 that covers a part or all of a tube end face 25, a side surface plate 72 that is connected to the end face plate 71 and covers a part or all of a side face 27, and a molded resin 9. The side face 27 is adjacent to both an opening face 23 exposed from the coil coating resin 3 and the tube end face 25. The end face plate 71 has a slit 8 that is cut from a corner 722 of the side surface plate 72 in a side edge 711 of the end face plate 71, and extends along a longitudinal side 724 that is a boundary line between the end face plate 71 and the side surface plate 72. The side surface plate 72 is separated from the end face plate 71 by the slit 8, but is connected to the end face plate 71 at a cut terminal 84 of the slit 8.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a molded coil formed by molding a coil with resin, and to a reactor having this molded coil. [Background technology]

[0002] A reactor mainly consists of a coil and a core. When electricity is passed through the coil, it generates magnetic flux according to the number of turns. Hereinafter, the coil that functions as an inductive reactance by generating magnetic flux when electricity is passed through it from the outside is called the main coil. The core is a closed magnetic circuit that passes the magnetic flux generated by the coil according to a magnetic permeability higher than that of a vacuum. This reactor is an electromagnetic component that converts electrical energy into magnetic energy and stores and releases it.

[0003] Such reactors are used in a wide variety of applications, and representative examples include boost reactors, series reactors, parallel reactors, current limiting reactors, starting reactors, shunt reactors, neutral point reactors, and arc suppression reactors.

[0004] Boost reactors are incorporated into on-board boost circuits such as those used in the drive systems of hybrid and electric vehicles. Series reactors are connected in series with motor circuits to limit the current during short circuits. Parallel reactors stabilize the current sharing between parallel circuits. Current-limiting reactors limit the current during short circuits. Starting reactors are connected in series with motor circuits to protect the machine and limit the starting current. Shunt reactors are connected in parallel with transmission lines to compensate for leading reactive power and suppress abnormal voltages. Neutral point reactors are connected between the neutral point and the ground to limit the ground fault current that flows in the event of a ground fault in the power system. Arc-suppression reactors automatically extinguish the arc that occurs when a single-line ground fault occurs in a three-phase power system.

[0005] A molded coil may be used in a reactor, in which the outer circumference of the coil is covered with a resin coating. The coating of the molded coil electrically insulates the coil from the core. However, in order to ensure the heat dissipation of the coil, a part of the coil surface may be left exposed without being covered with molding resin. In order to expose the coil surface, a proposal has been made to fill the surrounding area with molding resin while pressing a mold against the coil surface (see Patent Documents 1 and 2). The mold prevents the molten resin from leaking into the area to be exposed, and an opening is created that is exposed from the coating. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-130410 A [Patent Document 2] JP 2018-011019 A [Patent Document 3] JP 2010-147106 A Summary of the Invention [Problem to be solved by the invention]

[0007] The coil surface is uneven and is not necessarily smooth. Therefore, even if the coil is to be tightly attached to the mold, a gap will be generated between the mold and the coil surface. If this occurs, resin may enter through the gap and cause burrs to form on the exposed surface. For example, when the bottom surface of the coil is to be set as the opening surface for the covering, a plate material is placed on the side of the coil, spanning both ends of the coil (see Patent Document 3).

[0008] When a plate material is placed over the side of the coil and pressed against the side of the coil, the plate material must be thin enough to be deformable under the pressure. However, if the plate material is thin, the insulation performance is reduced. On the other hand, if the plate material is thick, it cannot be deformed enough to be in close contact with the side of the coil, which reduces the effect of preventing resin leakage to the opening surface and deteriorates the heat dissipation performance of the reactor.

[0009] In addition, the plate is bridged between the flanges. As a result, when the plate tries to deform, the flanges are stretched, and the plate cannot be deformed by being pressed against the coil near its end. This causes a gap between the coil and the plate near its end, causing resin to leak into the opening, and deteriorating the heat dissipation of the reactor.

[0010] The present invention has been made to solve the above-mentioned problems, and its object is to provide a molded coil and a reactor that have excellent heat dissipation properties by suppressing resin leakage to the opening surface. [Means for solving the problem]

[0011] In order to solve the above-mentioned problems, the molded coil of this embodiment comprises a cylindrical coil which is a wound body of a conductive wire, and a coil coating resin which covers part or all of the coil, wherein the coil has an end face perpendicular to a winding axis, an opening face which extends along the winding axis and is exposed from the coil coating resin, and side faces adjacent to both the end face and the opening face, the coil coating resin has an end face plate which covers part or all of the end face, a side face plate which is connected to the end face plate and covers part or all of the side face, and a molded resin, wherein the end face plate has a slit which is cut into a corner or near a corner of the side plate among the side edges of the end face plate and extends along the boundary line between the end face plate and the side plate, and the side plate is separated from the end face plate at the slit and connected to the end face plate at a cutting end terminal of the slit.

[0012] The slit may cut into the end plate from a corner of the side plate that is away from the opening surface or near the corner, and extend toward the opening surface.

[0013] The end surface of the coil may be an annular surface, and the slit may extend between an inner periphery and an outer periphery of the annular surface and extend across the annular surface.

[0014] The slit may have a curved portion that changes direction from a cut start point to a cut end point of the end plate.

[0015] The end face plates may include a first end face plate covering one of the end faces of the coil and a second end face plate covering the other end face of the coil, and the side face plates may include a first side face plate connected to the first end face plate and a second side face plate connected to the second end face plate on the same side face of the coil, the first end face plate and the second end face plate each having the slit, the first side face plate being separated from the first end face plate at the slit and connected to the first end face plate at an end of the slit, and the second side face plate being separated from the second end face plate at the slit and connected to the second end face plate at an end of the slit.

[0016] In order to solve the above-mentioned problems, the reactor according to this embodiment includes such a molded coil, and a core including a magnetic body and on which the molded coil is attached. Effect of the Invention

[0017] According to the present invention, the molded coil has excellent heat dissipation properties by suppressing resin leakage to the opening surface. [Brief description of the drawings]

[0018] [Figure 1] FIG. [Diagram 2]FIG. [Diagram 3] FIG. 2 is a perspective view of a coil equipped with a cylindrical annular cover. [Figure 4] FIG. 2 is a front view of a coil equipped with a cylindrical annular cover. [Diagram 5] FIG. 1 is a perspective view of a coil fitted with a walled annular cover. [Figure 6] FIG. 2 is a side view of a coil equipped with a cylindrical annular cover and a walled annular cover. [Figure 7] FIG. 2 is a perspective view showing a coil in a mold. [Figure 8] FIG. 4 is a front view showing the coil inside the mold. [Figure 9] FIG. 4 is a perspective view showing a coil covered with molding resin in a mold. [Figure 10] FIG. [Figure 11] FIG. 2 is a perspective view of a reactor including a secondary molding resin. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, a molded coil and a reactor according to an embodiment of the present invention will be described with reference to the drawings. In each drawing, thickness, dimensions, positional relationship, ratio, shape, and the like may be emphasized for ease of understanding, but the present invention is not limited to such emphasis.

[0020] Fig. 1 is a perspective view of a molded coil 1, and Fig. 2 is an exploded view of the molded coil 1. The molded coil 1 is a main component of a reactor 100 (see Fig. 10) together with a core 110 (see Fig. 10) containing a magnetic body. The molded coil 1 is attached to the core, and generates magnetic flux according to the number of turns when electricity is applied. The core in which the molded coil 1 is fitted becomes a closed magnetic circuit that passes the magnetic flux generated by the molded coil 1 with a magnetic permeability higher than that of a vacuum. For this reason, the reactor is an electromagnetic component that converts electric energy into magnetic energy and stores and releases it.

[0021] One or more molded coils 1 are attached to the core. For example, as shown in Figures 1 and 2, two molded coils 1 with winding axes 21 extending in parallel are attached to one core. The two molded coils 1 attached to one core may be separate bodies, or may be linked coils connected in series.

[0022] Each molded coil 1 includes a coil 2 and a coil coating resin 3. The coil 2 is a cylindrically wound body of conductive wire such as enamel-coated copper wire. The coil 2 is formed by spirally winding the conductive wire along a winding axis 21 while shifting the winding position for each turn. The coil coating resin 3 is a resin cover that covers a part or the entire surface of the coil 2. The coil coating resin 3 protects the coil 2 from mechanical shocks, and also covers at least the area where the coil 2 and the core are close to each other, electrically insulating the coil 2 from the core.

[0023] The coil 2 is, for example, a helical edgewise coil. The helical edgewise coil is formed by winding a rectangular conductive wire so that the wide surface of the conductive wire extends in a direction perpendicular to each winding axis 21. The coil 2 has a cylindrical end surface 25 and a cylindrical end surface 26 from which a lead wire 22 is drawn out. Electricity is applied to the coil 2 through the lead wire 22. If the coil 2 is a linked coil, the cylindrical end surfaces 26 are linked to each other.

[0024] Here, the cylinder end surface 25 and the cylinder end surface 26 are formed by the outermost turn of the conductive wire on the lead-out side, and are end surfaces that extend perpendicular to the winding axis 21 and have a ring shape. The coil 2 has an upper surface 24, an opening surface 23, a side surface 27, and an opposing surface 28 that extend along the winding axis 21 between the cylinder end surface 25 and the cylinder end surface 26. The upper surface 24 is the upper surface that is pressed by the mold during resin molding. The opening surface 23 is the surface opposite to the upper surface 24, and a part or the entire surface is exposed from the coil coating resin 3 even after resin molding for heat dissipation. The side surface 27 is adjacent to the cylinder end surface 25, the cylinder end surface 26, and the opening surface 23, and is located on the opposite side away from the adjacent coil 2. The opposing surface 28 is located on the opposite side of the side surface 27 and faces the adjacent coil 2.

[0025] The term "upper" refers to the upper and lower dies that house the coil 2 when the coil 2 is resin-coated by molding, and does not refer to the positional relationship or direction when the coil 2 is mounted on the actual device to be installed. The coil 2 may have curved surfaces in addition to the upper surface 24, the opening surface 23, the side surface 27, and the opposing surface 28, and may have an outer shape in which the curved surfaces are alternately arranged with the upper surface 24, the opening surface 23, the side surface 27, and the opposing surface 28. The upper surface 24, the opening surface 23, the side surface 27, and the opposing surface 28 may be flat surfaces or curved surfaces. Surfaces that form a large arc with a gentle curvature due to the bulging of the conductive wire are also included in the flat surfaces.

[0026] The coil coating resin 3 is an insulating material such as epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), PBT (Polybutylene Terephthalate), or a composite of these, and may contain a thermally conductive filler mixed in.

[0027] As shown in Fig. 1, this coil coating resin 3 has a portion thereof coated with molded resin 9. For convenience of explanation, the molded resin 9 is omitted from Fig. 2. The molded resin 9 is formed by placing the coil 2 in a mold, and then injecting molten resin into it. The molten resin is solidified and molded so as to cover a portion of the coil 2.

[0028] As shown in Fig. 2, the coil coating resin 3 includes a top cover 4, a cylindrical annular cover 5, and a walled annular cover 6. The top cover 4, the cylindrical annular cover 5, and the walled annular cover 6 function as buffer materials between the coil 2 and the mold, and as a resin-cutting barrier that prevents resin leakage to the opening surface 23. The top cover 4, the cylindrical annular cover 5, and the walled annular cover 6 are pre-formed products whose shapes are set before coating the coil 2, and are attached to the coil 2 before the coil 2 is placed in the mold.

[0029] The top cover 4 includes top plates 41 placed on the two coils 2 and a connecting portion 42 connecting both top plates 41. The top cover 4 is an integrally molded product, and both top plates 41 are seamlessly connected to each other via the connecting portion 42. The top plate 41 is disposed on the top surface 24 of the coil 2. This top plate 41 is interposed between a die for molding the molded resin 9 and the top surface 24 to protect the top surface 24 when the die presses the top surface 24 to correct unevenness of the top surface 24.

[0030] The tube-attached annular cover 5 comprises an inner tube 51, an end plate 71, and a side plate 72. The tube-attached annular cover 5 is a one-piece molded product, and the inner tube 51, end plate 71, and side plate 72 are connected in a continuous manner without any seams. The inner tube 51 is a cylindrical body whose outer diameter matches the inner peripheral shape of the coil, and is inserted into the inner circumference of the coil 2 to cover the inner peripheral surface of the coil 2. The end plate 71 of the tube-attached annular cover 5 is a ring-shaped plate that encompasses the tube end surface 25 of the coil 2, and covers the tube end surface 25.

[0031] The side plate 72 of the tube-attached annular cover 5 is a plate that covers the side surface 27 of the coil 2, and extends from the edge of the tube end surface 25 of the coil 2 toward the opposite tube end surface 26. However, the side plate 72 of the tube-attached annular cover 5 does not reach the tube end surface 26. This side plate 72 may be at the same height as the side surface 27 of the coil 2 in the height direction connecting the opening surface 23 and the top surface 24 of the coil 2, or may be lower, and covers part or all of the side surface 27.

[0032] The walled annular cover 6 includes end plates 71 disposed on the two coils 2, side plates 72 disposed on the two coils 2, and an inner abutment wall 61. The walled annular cover 6 is an integrally molded product, and the two end plates 71, the two side plates 72, and the inner abutment wall 61 are connected seamlessly. The end plate 71 of the walled annular cover 6 is a ring-shaped plate that encompasses the cylindrical end surface 26 of the coil 2 and covers the cylindrical end surface 26.

[0033] The side plate 72 of the walled annular cover 6 is a plate that covers the side surface 27 of the coil 2, and extends from the edge of the cylindrical end surface 26 of the coil 2 toward the opposite cylindrical end surface 25. However, the side plate 72 of the walled annular cover 6 does not reach the cylindrical end surface 25. This side plate 72 may be at the same height as the side surface 27 of the coil 2 in the height direction connecting the opening surface 23 and the top surface 24 of the coil 2, or may be lower, and covers part or all of the side surface 27.

[0034] The inner abutment wall 61 is a wall that fits between the two coils 2 and covers each opposing surface 28 of the two coils 2. The inner abutment wall 61 may be at the same height as the opposing surface 28 of the coil 2 in the height direction connecting the opening surface 23 and the upper surface 24 of the coil 2, or may be low in height, and covers a part or all of the opposing surface 28.

[0035] The cylindrical annular cover 5 will be described in further detail. Fig. 3 is a perspective view of the coil 2 equipped with the cylindrical annular cover 5, and Fig. 4 is a front view of the coil 2 equipped with the cylindrical annular cover 5. As shown in Figs. 3 and 4, the end plate 71 and the side plate 72 are partially torn by the slit 8. A connecting portion 712 between the end plate 71 and the side plate 72 remains in a portion on the opening surface 23 side.

[0036] The slit 8 is a long cut extending from the side edge 711 of the end plate 71. This slit 8 has a cut-in start end 81 facing a corner 722 on the end plate 71 side at the upper side edge 721 of the side plate 72. In other words, the slit 8 cuts into the end plate 71 from a position of the side edge 711 of the end plate 71 facing this corner 722.

[0037] Incidentally, an upper side edge 721 of the side plate 72 extends along the winding shaft 21 on the upper surface 24 side of the coil 2. The side plate 72 has an opening side edge 723 that extends along the winding shaft 21 on the opening surface 23 side of the coil 2. The opening side edge 723 is the opposite side to the upper side edge 721. The side plate 72 also has a vertical side 724 that extends between the upper side edge 721 and the opening side edge 723, and the vertical side 724 is connected to a side edge 711 of the end plate 71.

[0038] The slit 8 cuts into the end plate 71 from the cutting start point 81, changes its extending direction toward the opening surface 23 at the curved portion 82, and extends along the vertical side 724 of the side plate 72 at the straight portion 83. The straight portion 83 of the slit 8 passes over the annular surface of the cylindrical end surface 25 of the coil 2. In other words, the straight portion 83 of the slit 8 passes between the inner peripheral diameter and the outer peripheral diameter of the cylindrical end surface 25 of the coil 2. Therefore, the region between the slit 8 and the side edge 711 of the end plate 71 remains on the side plate 72 side.

[0039] The cut end 84 of the straight portion 83 of the slit 8 does not reach the side edge 711 of the end plate 71. Therefore, at the cut end 84, a connecting portion 712 connecting the end plate 71 and the side plate 72 remains.

[0040] 5 is a perspective view of the coil 2 fitted with the walled annular cover 6. As shown in FIG. 5, the walled annular cover 6 covering the tube end face 26 opposite to the tube end face 25 has the same slit 8 as the tube-attached annular cover 5. The slit 8 has a cut-out starting end 81 on the side edge 711 of the end face plate 71 of the walled annular cover 6. The cut-out starting end 81 faces a corner 722 on the upper side edge 721 of the side plate 72 of the walled annular cover 6.

[0041] The slit 8 cuts into the end plate 71 from the cut-out starting point 81, changes its extending direction toward the opening surface 23 at the curved portion 82, and extends along the vertical side 724 of the side plate 72 at the straight portion 83. The straight portion 83 of the slit 8 passes between the inner peripheral diameter and the outer peripheral diameter of the cylindrical end surface 25 of the coil 2. The cut-out ending point 84 does not reach the side edge 711 of the end plate 71, and a connecting portion 712 that connects the end plate 71 and the side plate 72 of the walled annular cover 6 remains.

[0042] As shown in Fig. 6, which is a side view of the coil 2 with the tube-equipped annular cover 5 and the wall-equipped annular cover 6 attached, a side plate 72, which is a first side plate extending from the tube-equipped annular cover 5, and a side plate 72, which is a second side plate extending from the wall-equipped annular cover 6, are arranged on the same side surface 27 of the coil 2, i.e., two side surfaces 72 are arranged. One vertical side 724 of the two side surfaces 72 is partially separated from the end surface plate 71 by a slit 8, and the other vertical side 724 is a free end. The two side surfaces 72 butt the vertical sides 724 of the free ends together to cover the area between the tube end surface 25 and the tube end surface 26 of the side surface 27 of the coil 2.

[0043] Fig. 7 is a perspective view showing the coil 2 in the mold, and Fig. 8 is a front view showing the coil 2 in the mold. The molded coil 1 is covered with the remaining molding resin 9 by attaching the top cover 4, the tube-equipped annular cover 5, and the wall-equipped annular cover 6 to the coil 2 and housing it in the mold. In the mold, the upper die presses the top plate 41 to correct unevenness in the area in close contact with the top surface 24, the inner abutment wall 61 of the wall-equipped annular cover 6, and the area in close contact with the lower die ML. The lower die ML is in close contact with the coil 2 on the outside of the opening surface 23 of the coil 2, and also serves as a barrier to prevent the molten resin from entering the opening surface 23.

[0044] In the die, in addition to the lower die ML, the slide die MS is also pressed against the coil 2. The slide die MS abuts against the side plate 72 and presses the side plate 72 against the side surface 27 of the coil 2. The slits 8 make the side plate 72 easy to displace. The connecting portion 712 connecting the end face plate 71 and the side plate 72 serves as a fulcrum, and the side plate 72 is displaced to narrow the slit 8 and comes into close contact with the side surface 27 of the coil 2.

[0045] Therefore, side plate 72 can be displaced more, and even if coil 2 has a small diameter within the range of individual differences, side plate 72 can be well adhered to side surface 27, and a gap can be eliminated between side plate 72 and side surface 27. Therefore, side plate 72 serves as a barrier that effectively prevents molten resin from penetrating into opening surface 23, even if coil 2 is an individual with a small diameter.

[0046] The side surface 27 of the coil 2 is covered by two side plates 72. In other words, the plate covering the side surface 27 is divided into two side plates 72. Each side plate 72 has a free end. Therefore, each side plate 72 is more easily displaced and can adhere tightly to the side surface 27 of the coil 2.

[0047] Moreover, the slits 8 are formed in the end plate 71. Therefore, the entire area of ​​the side plate 72, including the vertical side 724, is easily displaced. As a result, gaps can be eliminated over the entire area of ​​the side plate 72, and the infiltration of the molten resin into the opening surface 23 is more reliably prevented.

[0048] Fig. 9 is a perspective view showing the coil 2 covered with molded resin 9 in a mold. As shown in Fig. 9, the side plate 72 and the lower mold ML act as barriers to prevent the molten resin injected into the mold from entering the opening surface 23. The molten resin flows into the areas exposed from the mold, the top cover 4, the cylinder-equipped annular cover 5, and the wall-equipped annular cover 6, excluding the opening surface 23, and solidifies. As a result, the molded resin 9 is formed around the coil 2.

[0049] The molten resin also flows into the slits 8 from the cut starting end 81. Since the straight portion 83 of the slit 8 passes through the curved portion 82, the molten resin flows sufficiently toward the cut end 84 of the slit 8. Each slit 8 passes over the annular surfaces of the cylinder end faces 25 and 26. Therefore, the molten resin is prevented from leaking out from the slits 8 to between the side plate 72 and the side face 27, and leakage of resin into the opening surface 23 is more reliably prevented.

[0050] In this way, the molded coil 1 includes a cylindrical coil 2 which is a wound body of a conductive wire, and a coil coating resin 3 which coats a part or all of the coil 2. The coil 2 has a cylindrical end face 25 which is perpendicular to the winding axis 21, an opening face 23 which extends along the winding axis 21 and is exposed from the coil coating resin 3, and a side face 27 which is adjacent to both the cylindrical end face 25 and the opening face 23. The coil coating resin 3 has an end face plate 71 which covers a part or all of the cylindrical end face 25, a side face plate 72 which is connected to the end face plate 71 and covers a part or all of the side face 27, and a molded resin 9.

[0051] The end plate 71 has a slit 8 that is cut into the side edge 711 of the end plate 71 from a corner 722 of the side plate 72 and extends along a vertical side 724 that is the boundary between the end plate 71 and the side plate 72. The side plate 72 is separated from the end plate 71 by the slit 8, but is connected to the end plate 71 at a cut end 84 of the slit 8.

[0052] This allows the side plate 72 to be easily displaced and easily come into close contact with the side surface 27 of the coil 2, eliminating any gap between the side plate 72 and the side surface 27. Therefore, even if the coil 2 is an individual body with a small diameter, the molded coil 1 is excellent in heat dissipation properties because resin leakage to the opening surface 23 is suppressed.

[0053] Although the slit 8 has the cut starting end 81 at a position facing the corner 722 of the side plate 72, the cut starting end 81 may be in the vicinity of this corner 722. For example, the cut starting end 81 may be set closer to the top surface 24 than the corner 722. Also, the slit 8 may have the cut starting end 81 on the opening surface 23 side of the vertical side 724 of the side plate 72, and the straight portion 83 may extend toward the top surface 24. This also makes the side plate 72 more easily displaceable and more easily comes into close contact with the side surface 27 of the coil 2, and makes it possible to eliminate a gap between the side plate 72 and the side surface 27.

[0054] However, the slit 8 is configured to cut into the end plate 71 from a corner 722 or the vicinity of the corner 722 away from the opening surface 23, and extend toward the opening surface 23. A gap is most likely to occur between the upper side edge 721 of the side plate 72 and the side surface 27, and molten resin is most likely to enter between them. However, by making the corner 722 or the vicinity of the corner 722 of the upper side edge 721 the cutting start end 81 of the slit 8, the upper side edge 721 of the side plate 72 and the side surface 27 can be most strongly adhered to each other.

[0055] In addition, the tube end surface 25 of the coil 2 is an annular surface, and the slits 8 extend between the inner and outer circumferences of the annular surface and extend on the annular surface. This prevents the molten resin from penetrating between the side plate 72 and the side surface 27 of the coil 2 through the slits 8, and more reliably prevents the resin from leaking to the opening surface 23.

[0056] However, there is no limitation on the type of conductive wire, and other types of wires such as round wires may be used. In addition, there is no limitation on the winding manner of coil 2, and the conductive wire may be a flatwise coil in which the wide surface of the conductive wire extends along winding axis 21.

[0057] In addition, the slit 8 has a curved portion 82 that changes direction from a cutting start end 81 into the end plate 71 to a cutting end 84. This allows the molten resin to flow into the slit 8 toward the cutting end 84 of the slit 8 without being stagnant at the curved portion 82.

[0058] The end surface plates 71 include a first end surface plate 71 covering one cylindrical end surface 25 of the coil 2, and a second end surface plate 71 covering the other cylindrical end surface 26 of the coil 2. The side surface plates 72 include a first side surface plate 72 connected to the first end surface plate 71, and a second side surface plate 72 connected to the second end surface plate 71, on the same side surface 27 of the coil 2. The first end surface plate 71 and the second end surface plate 71 each have a slit 8.

[0059] That is, the side plate 72 is divided into two pieces. This makes the side plate 72 more easily displaceable and more easily comes into close contact with the side surface 27 of the coil 2, and makes it possible to eliminate a gap between the side plate 72 and the side surface 27.

[0060] FIG. 10 is a perspective view of the reactor 100. The above-mentioned molded coil 1 is attached to a core 110, and constitutes the reactor 100 together with the core 110. The core 110 includes 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), and a mixed powder of two or more of these powders. The magnetic powder may be an amorphous alloy or a nanocrystalline alloy powder. The metal composite core is a core formed by kneading and molding a magnetic powder and a resin.

[0061] The core 110 may have a ring shape, and the magnetic material may be distributed in a ring shape without interruption. A magnetic gap for preventing a decrease in inductance may be provided in the middle of the core 110. The magnetic gap may be made of a non-magnetic material, ceramic, non-metal, resin, carbon fiber, or a composite material of two or more of these, gap paper, or an air gap.

[0062] 11 is a perspective view of reactor 100 including secondary molded resin 120. Reactor 100 may include secondary molded resin 120, and molded coil 1 and core 110 may be covered with secondary molded resin 120 except for opening surface 23.

[0063] The above-mentioned embodiment of the present invention is presented as an example, and is not limited to the above-mentioned embodiment. The above-mentioned embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. The embodiment and its modifications are included in the scope of the present invention. [Explanation of symbols]

[0064] 1 Molded coil 2 Coil 21 Reel 22 Leader 23 Opening surface 24 Top side 25 Cylinder end face 26 Cylinder end surface 27 Side 28 Opposite Surface 3 Coil coating resin 4 Top cover 41 Top plate 42 Connecting part 5 Circular cover with tube 51 Inner cylinder 6 Wall-mounted circular cover 61 Inner abutment wall 71 End Plate 711 Side edge 712 Connection part 72 Side Plate 721 Upper side 722 Corner 723 Opening side 724 Vertical Side 8 Slit 81 Cutting start point 82 Curved section 83 Straight section 84 Cutting End 9. Mold Resin 100 Reactor 110 cores 120 Secondary molding resin ML lower mold MS Slide Type

Claims

1. A cylindrical coil which is a wound body of a conductive wire; A coil coating resin that coats a part or the whole of the coil; Equipped with the coil has an end surface perpendicular to the winding axis, an opening surface extending along the winding axis and exposed from the coil coating resin, and a side surface adjacent to both the end surface and the opening surface; the coil coating resin includes an end face plate covering a part or the whole of the end face, a side face plate connected to the end face plate and covering a part or the whole of the side face, and a molding resin; the end plate has a slit that is cut into a corner or a vicinity of a corner of the side plate among the side edges of the end plate and extends along a boundary line between the end plate and the side plate, the side plate is separated from the end plate at the slit and connected to the end plate at a cut end of the slit; A molded coil characterized by:

2. the slit cuts into the end plate from a corner of the side plate that is away from the opening surface or a corner near the corner, and extends toward the opening surface; 2. The molded coil according to claim 1,

3. the end surface of the coil is an annular surface; the slit extends between an inner periphery and an outer periphery of the annular surface and extends over the annular surface; 2. The molded coil according to claim 1,

4. The slit has a curved portion that changes direction from a cutting start end to a cutting end end of the end plate; 2. The molded coil according to claim 1,

5. The end surface plates include a first end surface plate covering one of the end surfaces of the coil and a second end surface plate covering the other end surface of the coil, the side plate includes a first side plate connected to the first end plate and a second side plate connected to the second end plate on the same side of the coil, the first end plate and the second end plate each have the slit, the first side plate is separated from the first end plate at the slit and connected to the first end plate at a cut end of the slit; the second side plate is separated from the second end plate at the slit and is connected to the second end plate at a cutting end of the slit; 2. The molded coil according to claim 1,

6. A molded coil according to any one of claims 1 to 5; a core including a magnetic material and to which the molded coil is attached; A reactor comprising:

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