Manufacturing method of molded coil, manufacturing method of reactor, molded coil, and reactor

Abstract

To provide a molded coil manufacturing method and a molded coil that improve moldability in molding.SOLUTION: A method includes a cover mounting step of mounting an upper cover 3 and a pressing surface cover 4 around a coil 2, and a pressing step of, after the cover mounting step, pressing the coil 2 along a winding axis by a pressing member or resin injection pressure to compress the coil 2. The coil 2 has a pressing surface 22, which is one end surface perpendicular to the winding axis, that is pressed in the pressing step. The upper cover 3 has a protruding portion 34 that protrudes from one end of the upper cover toward the pressing surface 22. In the pressing step, the upper cover 3 and the pressing surface cover 4 move along the winding axis as the coil 2 is compressed.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a manufacturing method of a molded coil formed by molding, a manufacturing method of a reactor, a molded coil, and a reactor. [Background technology]

[0002] Coil components are used in a variety of applications, including office automation equipment, solar power generation systems, and automobiles. An example of a coil component is a reactor. A reactor is an electromagnetic component that converts electrical energy into magnetic energy and stores and releases the energy.

[0003] The coil component mainly includes a core, a coil, and a resin member. The core is made of a magnetic material, such as a powder magnetic core. The coil is wound around the outer periphery of the core. A resin member is provided between the core and the coil to insulate them from each other.

[0004] In recent years, molded coils made of resin are widely used. The coil is placed in a predetermined position in a mold, resin is injected into the mold, and the resin is allowed to harden. In this way, a molded coil is produced in which the coil is covered with a resin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-129288 A Summary of the Invention [Problem to be solved by the invention]

[0006] A coil is made by winding a conductive member. When making a coil, there is a variation in the winding. Therefore, the length of the coil in the winding axis direction is made slightly longer than the desired length, and the coil is pressed in the winding axis direction during molding to adjust it to the desired length.

[0007] The coil is surrounded by covers so that the mold, pressing member, and injected resin do not come into direct contact with the coil. For example, as shown in Fig. 16, the coil 120 has a pressing surface 130 and a fixed surface 140 that are perpendicular to the winding axis. The pressing surface 130 is covered by a pressing surface cover 150. The fixed surface 140 is covered by a fixed surface cover 160. An upper surface cover 170 is disposed on the upper surface of the coil 120. Protrusions 180 extend downward from both ends of the upper surface cover 170. The pressing surface cover 150, the coil 2, and the fixed surface cover 160 are sandwiched between the two protrusions 180.

[0008] Then, the coil 120 with the covers 150, 160, 170 attached thereto is placed in a metal mold and molded. A gate G for injecting resin is provided on the pressing surface 130 side, and the resin is injected toward the pressing surface 130. The pressing surface 130 is pressed toward the fixed surface 140 side by a pressing member. The fixed surface 140 is fixed by a metal mold or a jig via the fixed surface cover 160, so that the coil 120 is compressed toward the fixed surface 140 side.

[0009] When the coil 120 is compressed, the pressing surface cover 130 moves toward the fixed surface 140 in conjunction with the compression. On the other hand, the upper surface cover 170 has protrusions 180 formed at both ends, and the protrusions 180 on the fixed surface 140 side are supported by a mold or a jig, so that the upper surface cover 170 cannot move. Therefore, a gap is generated between the protrusions 180 and the pressing surface cover 150. If the resin continues to be injected with a gap generated, the protrusions 180 may be deformed by the injection pressure, or the injection pressure required for compression may not be applied to the pressing surface cover 150. As a result, the coil 120 cannot be compressed to the desired length, and moldability is deteriorated.

[0010] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a manufacturing method for a molded coil and a molded coil that improves formability in molding. [Means for solving the problem]

[0011] The manufacturing method of a molded coil of the present invention is a manufacturing method of a molded coil that molds a coil, and includes a cover attachment process of attaching a cover around the coil, and a pressing process of pressing the coil along a winding axis by an injection pressure of a pressing member or resin after the cover attachment process, thereby compressing the coil, wherein the coil has a pressing surface which is one end surface perpendicular to the winding axis and is pressed in the pressing process, the cover has an upper cover that covers an upper surface of the coil, and a pressing surface cover that is separate from the upper cover and covers the pressing surface of the coil, the upper cover has a protrusion that protrudes from one end of the upper cover toward the pressing surface, and the upper cover and the pressing surface cover move along the winding axis in response to the compression of the coil in the pressing process.

[0012] The molded coil of the present invention further comprises a coil formed by winding a conductive material, a cover covering the periphery of the coil, and a coil molded resin part integrating the coil and the cover, wherein the coil has a pressing surface which is one end surface perpendicular to the winding axis, the cover has an upper cover covering an upper surface of the coil, and a pressing surface cover covering the pressing surface, the upper cover has a protrusion protruding from one end of the upper cover toward the pressing surface, the coil molded resin part has a pressing surface covering part which covers the pressing surface from above the pressing surface cover, and the pressing surface covering part has at least one of an injection mark and a recessed portion formed therein.

[0013] The present invention also provides a reactor including the above molded coil and a core including a magnetic body and on which the molded coil is attached, and a method for manufacturing the reactor. Effect of the Invention

[0014] According to the present invention, a manufacturing method of a molded coil and a molded coil that improves moldability in molding can be obtained. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a perspective view showing the overall configuration of a molded coil. [Diagram 2] FIG. 4 is a perspective view showing a state before a coil cover is attached. [Diagram 3] FIG. 4 is a perspective view showing a state in which a cover is attached to the coil. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] 13 is a perspective view showing a state in which the protrusion and the pressing surface cover are fitted together. FIG. [Figure 7] FIG. [Figure 8] 8 is an enlarged perspective view of a cutout of a portion circled by a dotted line in FIG. 7. FIG. [Figure 9] FIG. [Figure 10] FIG. [Figure 11] 13 is an enlarged perspective view of a recessed portion when the pressing surface cover and the inner peripheral surface cover are attached to the coil. FIG. [Figure 12] 13 is an enlarged perspective view of the cutout when the pressing surface cover and the inner peripheral surface cover are attached to the coil. FIG. [Figure 13] FIG. 2 is a perspective view showing the overall configuration of a reactor. [Figure 14] FIG. 2 is a schematic diagram showing a state during molding of a coil. [Figure 15] 13A and 13B are diagrams illustrating an attached state of the upper cover and the pressing surface cover in another embodiment. [Figure 16] FIG. 13 is a schematic diagram showing a state during molding of a coil in a conventional example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] (Embodiment) A molded coil 1 according to an embodiment will be described with reference to the drawings. Fig. 1 is a perspective view showing the overall configuration of the molded coil 1. Fig. 2 is a perspective view showing the coil 2 before a cover is attached. Fig. 3 is a perspective view showing the coil 2 with a cover attached. In each drawing, thickness, dimensions, positional relationships, ratios, shapes, and the like may be emphasized for ease of understanding, but the present invention is not limited to such emphasis.

[0017] The molded coil 1 is a main component of a coil part such as a reactor 9 (see FIG. 13). As shown in FIGS. 1 to 3, the molded coil 1 includes a coil 2, an upper cover 3, a pressing surface cover 4, an inner circumferential surface cover 5, and a coil molded resin part 6. The molded coil 1 is produced by molding the coil 2, the upper cover 3, the pressing surface cover 4, and the inner circumferential surface cover 5 with the resin that constitutes the coil molded resin part 6. The coil 2 is compressed to a desired length by molding, and is integrated in the compressed state.

[0018] Coil 2 is composed of a single conductive member that is insulated with enamel or the like. Coil 2 is formed by winding the conductive member into a cylindrical shape while shifting the winding position in the winding axis direction. The conductive member is, for example, a rectangular wire. Coil 2 is an edgewise coil in which the wide surface of the rectangular wire extends in a direction perpendicular to the winding axis of coil 2. Coil 2 may also be a flatwise coil. Also, a round wire may be used as the conductive member.

[0019] Two coils 2 are provided. The coils 2 are arranged side by side so that their winding axes are parallel. The two coils 2 are connected by a connecting wire 21 to form a connected coil. The connecting wire 21 is provided on the pressing surface 22 side described later. The upper surface of the connecting wire 21 is flush with the upper surface of the coil 2. The up-down direction is a direction perpendicular to the winding axis direction and perpendicular to the lateral arrangement direction of the coils 2, and does not refer to the up-down direction in a state in which the molded coil 2 is installed. The upper surface of the coil 2 is the surface of the coil 2 that faces the upper die of the metal mold during molding. It is sufficient that the upper surface of the connecting wire 21 is flush with the upper surface of the coil 2 or lower than the upper surface of the coil 2.

[0020] The coil 2 has four flat surfaces and four curved surfaces. The coil 2 has a rectangular cylindrical shape in which the four flat surfaces and the four curved surfaces are arranged alternately. The coil 2 has a pressing surface 22 and a fixing surface 23.

[0021] The pressing surface 22 is the surface that receives the resin injection pressure or is pressed by a pressing member during molding. The pressing surface 22 is one end surface that is perpendicular to the winding axis. In other words, the pressing surface 22 is the surface of the coil 2 that is perpendicular to the winding axis on the side where the injection mark M of the molded coil 1 is formed or on the side where a recess 63 (see FIG. 1) indicating a mark caused by pressing by a pressing member is formed. The pressing surface 22 is in a ring shape with an opening the same size as the inner diameter of the coil 2.

[0022] Fixing surface 23 is the surface of coil 2 that is perpendicular to the winding axis and is opposite pressing surface 22. Fixing surface 23 is fixed by a mold, jig, or the like via inner circumferential surface cover 5 during molding. Fixing fixing surface 23 by a mold, jig, or the like suppresses movement of coil 2 in the injection direction due to the injection pressure of the resin or the pressure of the pressing member.

[0023] The coil 2 has lead wires 24, 25 electrically connected to an external device. The lead wire 24 is drawn out from the fixed surface 23 along the winding axis direction. The lead wire 25 is drawn out from the fixed surface 23 along the lateral arrangement direction of the coil 2. The tips of the lead wires 24, 25 are connected to a bus bar (not shown) by welding or the like. The bus bar is connected to a terminal of the external device, and power is supplied to the coil 2 from the external device via the bus bar.

[0024] The upper cover 3, the pressing surface cover 4, and the inner peripheral cover 5 cover the periphery of the coil 2. The upper cover 3, the pressing surface cover 4, and the inner peripheral cover 5 prevent the coil 2 from directly contacting the mold, the pressing member, or the injected resin during molding. The upper cover 3, the pressing surface cover 4, and the inner peripheral cover 5 are each formed as a separate body.

[0025] The upper cover 3, the pressing surface cover 4, and the inner peripheral surface cover 5 are made of resin. Examples of the types of resin include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), and PBT (Polybutylene Terephthalate).

[0026] The upper cover 3 covers the upper surface of the coil 2. Fig. 4 is a perspective view of the upper cover 3. The upper cover 3 has a flat portion 31, a curved portion 32, a connecting portion 33, and a protruding portion .

[0027] The flat portion 31 covers the upper flat surface of the coil 2. Two flat portions 31 are provided, each covering a respective upper flat surface of the coil 2. The flat portions 31 come into contact with the upper die during molding, preventing the coil 2 from directly contacting the upper die. The flat portions 31 extend in the winding axis direction from the flat surface of the upper surface of the coil 2 on the pressing surface 22 side.

[0028] Fig. 5 is an enlarged view of the flat portion 31 on the fixed surface 23 side. As shown in Fig. 5, before molding, i.e., in a state where the upper cover 3 is attached to the coil 2, the flat portion 31 exposes a part of the upper flat surface of the coil 2 on the fixed surface 23 side. In other words, the tip surface 311 of the flat portion 31 on the fixed surface 23 side does not reach the fixed surface 23. In addition, the tip surface 311 is not in contact with the inner circumferential surface cover 5 either.

[0029] In the state of the molded coil 1 (after molding and the coil 2 is compressed), the tip surface 311 of the flat portion 31 may reach the fixing surface 23 or may extend beyond the fixing surface 23. In addition, in the state of the molded coil 1 (after molding and the coil 2 is compressed), the tip surface 311 may be in contact with the inner circumferential cover 5.

[0030] The curved portion 32 covers the curved surface located on the inside of the upper surface of the coil 2. The inside is the side where the two coils 2 face each other. The curved portion 32 has a shape following the curved surface of the coil 2. The curved portion 32 is connected to the flat portion 31. The tip surface 321 of the curved portion 32 is aligned with the tip surface 311 of the flat portion 31 and is flush with each other. In other words, a part of the curved portion 32 of the coil 2 on the fixing surface 23 side is exposed. The curved portion 32 does not contact the inner circumferential surface cover 5 at the stage where the upper cover 3 is attached to the coil 2. Two curved portions 32 are provided, and each curved portion 32 covers the curved surface of each coil 2.

[0031] The connecting portion 33 is provided between the coils 2. The connecting portion 33 is a flat plate-shaped member. The connecting portion 33 is connected to each curved portion 32. In other words, the connecting portion 33 connects two curved portions 32. The connecting portion 33 is provided with a plurality of holes 331. In this embodiment, five holes 331 are provided. The length of the connecting portion 33 in the winding axis direction is approximately the same as that of the flat portion 31. The tip of the connecting portion 33 does not contact the inner circumferential surface cover 5 at the stage when the upper cover 3 is attached to the coil 2.

[0032] The protruding portion 34 is a flat plate-shaped member. The protruding portion 34 protrudes downward from the end of the flat portion 31 on the pressing surface 22 side in the winding axis direction. The protruding portion 34 covers the upper central portion of the pressing surface 22 of the coil 2 directly or via the pressing surface cover 4. The protruding length of the protruding portion 34 needs only to be long enough to reach the opening of the pressing surface 22.

[0033] Fig. 6 is a perspective view showing the fitting state of the protrusion 34 and the pressing surface cover 4. As shown in Fig. 6, the protrusion 34 is inserted into the recess 412 or the hole 414 of the pressing surface cover 4. By inserting the protrusion 34 into the recess 412 or the hole 414, the upper cover 3 and the pressing surface cover 4 are fitted together and can move together in accordance with the compression of the coil 2.

[0034] 7 is a perspective view of the pressing surface cover 4. As shown in FIG. 7, the pressing surface cover 4 has a pressing surface protection portion 41, a connecting portion 42, a side protection portion 43, and a central extension portion 44. The pressing surface protection portion 41 covers the pressing surface 22. The pressing surface protection portion 41 is in a ring shape with an opening that is approximately the same as the inner diameter of the coil 2. The pressing surface protection portion 41 has a bulging portion 411 in which an upper central portion of the pressing surface protection portion 41 bulges outward in the winding axis direction. The outward direction of the winding axis is the direction away from the pressing surface 22 of the coil 2.

[0035] Here, there are provided two pressing surface protection parts 41. Of the two pressing surface protection parts 41, the one provided on the coil 2 on the side where the connecting wire 21 is arranged is referred to as pressing surface protection part 41a, and the one provided on the coil 2 on the side where the connecting wire 21 is not arranged is referred to as pressing surface protection part 41b.

[0036] The bulging portion 411a of the pressing surface protection portion 41a is generally U-shaped when viewed from the top-bottom direction. That is, the pressing surface protection portion 41a has a recessed portion 412 that is recessed outward in the roll axis direction on the surface of the bulging portion 411a that faces the pressing surface 22. The recessed portion 412 is large enough to allow the protrusion 34 of the upper cover 3 to be inserted therein.

[0037] On the other hand, the pressing surface protection portion 41b has a padding portion 413. The padding portion 413 is connected to the inner surface of the pressing surface protection portion 41b. That is, the pressing surface protection portion 41b is thicker than the pressing surface protection portion 41a by the padding portion 413. The inner surface of the pressing surface protection portion 41b is the surface facing the coil 2 (the surface closer to the coil 2) among the end surfaces of the pressing surface protection portion 41b perpendicular to the winding axis direction. The pressing surface protection portion 41b has a hole 414 surrounded by the bulge portion 411b and the padding portion 413. The hole 414 has a size and depth that allows the protrusion 34 of the upper cover 3 to be inserted therein.

[0038] The connecting portion 42 is provided between the coils 2. The connecting portion 42 connects the pressing surface protection portions 41a and 41b. That is, one end of the connecting portion 42 is connected to the pressing surface protection portion 41a, and the other end is connected to the pressing surface protection portion 41b. The connecting portion 42 has a hole 421.

[0039] Side surface protection portion 43 covers a portion of the outer surface of coil 2. The outer surface of coil 2 is a flat surface that is perpendicular to the lateral arrangement direction of coil 2 and opposite to the surface that coil 2 faces. Side surface protection portion 43 extends from the inner surface of pressing surface protection portion 41 along the winding axis direction toward fixed surface 23. A tip portion 431 of side surface protection portion 43 does not reach fixed surface 23.

[0040] The central extending portion 44 is provided between the coils 2. The central extending portion 44 extends from the inner surface of the connecting portion 42 along the winding axis direction toward the fixed surface 23. A tip portion 441 of the central extending portion 44 does not reach the fixed surface 23. The tip portion 441 has two notches 442.

[0041] Fig. 8 is an enlarged perspective view of the notch 442 shown in Fig. 7. The notch 442 is cut from the tip surface 441a of the tip portion 441 toward the connecting portion 42. An extension portion 54 of the inner circumferential cover 5, which will be described later, is inserted into the notch 442. The notch 442 has a side wall 443 facing the extension portion 54.

[0042] 9 is a perspective view of the inner circumferential surface cover 5. The inner circumferential surface cover 5 has an inner circumferential surface protection portion 51, a fixed surface protection portion 52, a side surface protection portion 53, and an extension portion 54. The inner circumferential surface protection portion 51 covers the inner circumferential surface of the coil 2. The inner circumferential surface protection portion 51 is cylindrical and has an outer shape following the inner circumferential surface of the coil 2. The inner circumferential surface protection portion 51 extends from the fixed surface protection portion 52 along the winding axis.

[0043] Fixed surface protection portion 52 covers fixed surface 23 of coil 2. Fixed surface protection portion 52 is annular with an opening that is approximately the same as the inner diameter of inner surface protection portion 51. Fixed surface protection portion 52 spreads out from the end of inner surface protection portion 51 on the fixed surface 23 side in the winding axis direction. Fixed surface protection portion 52 comes into contact with a metal mold or a jig during molding.

[0044] Side protective portion 53 covers the outer surface of coil 2. Side protective portion 53 extends from fixed surface protective portion 52 toward pressing surface 22 along the winding axis direction. FIG. 10 is an enlarged view of side protective portion 53. As shown in FIG. 10, side protective portion 53 has a recessed portion 531. Recessed portion 531 bulges in the direction away from coil 2, and its interior is a recessed space. Recessed portion 531 has a side wall 532 that faces the tip surface of tip portion 431 of side protective portion 43. This side wall 532 is a side wall that defines recessed portion 531, and is perpendicular to the winding axis.

[0045] Fig. 11 is an enlarged perspective view of the recessed portion 531 in a state where the pressing surface cover 4 and the inner circumferential surface cover 5 are attached to the coil 2. As shown in Fig. 11, in a state where the pressing surface cover 4 and the inner circumferential surface cover 5 are attached to the coil 2, the tip portion 431 of the side surface protection portion 43 is housed in the recessed portion 531 of the side surface protection portion 53. At that time, the tip surface of the tip portion 431 is not in contact with the side wall 532 of the recessed portion 531. In other words, there is a gap S1 between the tip surface of the tip portion 431 and the opposing side wall 532, and the pressing surface cover 4 is movable toward the fixed surface 23.

[0046] The extension portion 54 is provided between the coils 2. The extension portion 54 extends from the fixed surface protection portion 52 along the winding axis toward the pressing surface 22. FIG. 12 is an enlarged perspective view of the notch 442 in a state in which the pressing surface cover 4 and the inner circumferential surface cover 5 are attached to the coil 2. As shown in FIG. 12, in a state in which the pressing surface cover 4 and the inner circumferential surface cover 5 are attached to the coil 2, the extension portion 54 is inserted into the notch 442. At that time, the tip surface 541 of the extension portion 54 is not in contact with the side wall 443 of the notch 442, and a gap S2 is formed. That is, the pressing surface cover 4 is movable toward the fixed surface 23.

[0047] The coil mold resin part 6 covers the periphery of the coil 2, the upper cover 3, the pressing surface cover 4, and the inner circumferential surface cover 5. The coil mold resin part 6 integrates the coil 2, the upper cover 3, the pressing surface cover 4, and the inner circumferential surface cover 5.

[0048] The coil molded resin part 6 is made of resin. Examples of the resin that constitutes the coil molded resin part 6 include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), and PBT (Polybutylene Terephthalate). In particular, it is desirable to use a resin with high thermal conductivity. By using a resin with high thermal conductivity, the heat of the coil 2 can be transferred to the outside.

[0049] 1, the coil molded resin portion 6 has a pressing surface covering portion 61. The pressing surface covering portion 61 covers the pressing surface 22 of the coil 2 from above the pressing surface protection portion 41. The pressing surface covering portion 61 is in a ring shape having an opening that is approximately the same as the inner diameter of the coil 2. The pressing surface covering portion 61 has an exposed portion 62, an injection mark M, and a recessed portion 63.

[0050] The exposed portion 62 exposes the bulging portion 411 of the pressing surface protection portion 41. In other words, the exposed portion 62 does not cover the bulging portion 411 of the pressing surface protection portion 41 by the pressing surface covering portion 61. The exposed portion 62 is formed in the upper center portion of the pressing surface covering portion 61. The exposed portion 62 has a rectangular shape. Two exposed portions 62 are provided.

[0051] The injection mark M is a gate mark that indicates the position where resin is injected when the coil 2 is molded by the coil mold resin portion 6. The injection mark M is provided below the exposed portion 62. Two injection marks M are provided.

[0052] The recess 63 is a recess that is left by pressing the pressing surface 22 of the coil 2 with a pressing member during molding. That is, the shape of the recess 63 follows the shape of the pressing member. However, it is preferable that the recess 63 is circular, as shown in Fig. 1. If the recess 63 is circular, it is possible to prevent the fluidity of the resin from deteriorating during molding.

[0053] The recesses 63 are formed at two lower corners, two upper corners, and between the coils 2 on the pressing surface 22 of the coil 2. That is, a total of five recesses 63 are provided. From the recesses 63, the pressing surface protection portion 41 or the connecting portion 42 is exposed.

[0054] The outer diameter of the recessed portion 63 is preferably at least half the line width of the conductive member constituting the coil 2, and is preferably smaller than the line width. If the outer diameter of the recessed portion 63 is too large, the gap between the pressing member and the mold becomes small, making it difficult for the resin to flow. On the other hand, if the outer diameter of the recessed portion 63 is too small, the pressure increases, and there is a risk that the pressing surface protection portion 41, the connecting portion 42, or the pressing surface 26 of the coil 2 will be deformed.

[0055] The above molded coil 1 is used as a component of a reactor 9. The reactor 9 is an electromagnetic component that converts electric energy into magnetic energy and stores and releases it. FIG. 13 is a perspective view showing the overall configuration of the reactor 9. As shown in FIG. 13, the reactor 9 includes a core 7 and a secondary molded resin part 8. The core 7 includes a magnetic body. The core 7 may be a powder magnetic core, a ferrite core, a laminated steel plate, a metal composite core, or the like. The metal composite core is a magnetic body formed by kneading magnetic powder and resin and hardening the resin.

[0056] The core 7 is made of two U-shaped core members, and by joining the legs of the core 7, the core 7 becomes ring-shaped. A spacer may be inserted between the legs. The spacer may be made of a non-magnetic material, ceramic, non-metal, resin, carbon fiber, or a composite material of two or more of these, or gap paper. In this way, by using the spacer, a magnetic gap of a predetermined width is provided, and a decrease in inductance of the reactor 9 is prevented. Alternatively, an air gap may be provided instead of using a spacer.

[0057] The secondary molded resin part 8 covers the periphery of the molded coil 1 and the core 7. The secondary molded resin part 8 integrates the molded coil 1 and the core 7. The secondary molded resin part 8 is made of resin. The resin for the secondary molded resin part 8 may be the same type as that for the coil molded resin part 6. The secondary molded resin part 8 is formed by molding.

[0058] (Manufacturing method) Next, a manufacturing method of the molded coil 1 of this embodiment will be described with reference to the drawings. Fig. 14 is a schematic diagram showing a state during molding of the coil 2. The manufacturing method of the molded coil 1 of this embodiment includes a coil winding step, a cover attachment step, a die placement step, and a pressing step.

[0059] The coil winding process is a process of winding a conductive member to produce the coil 2. In the coil winding process, the conductive member is wound into a cylindrical shape while shifting the winding position in the direction of the winding axis. The length of the coil 2 produced in the coil winding process in the direction of the winding axis is configured to be slightly longer than the length after molding. This slightly longer configuration includes cases where the length is intentionally made longer and cases where the length is unintentionally made longer as a result of winding variations.

[0060] The cover mounting process is a process of mounting the upper cover 3, the pressing surface cover 4, and the inner circumferential surface cover 5 to the coil 2. The order of mounting the covers 3, 4, and 5 is, for example, first the inner circumferential surface cover 5, then the pressing surface cover 4, and finally the upper cover 3.

[0061] By attaching the inner circumferential surface cover 5 to the coil 2, the inner circumferential surface and the fixing surface 23 of the coil 2 are covered. After attaching the inner circumferential surface cover 5 to the coil 2, the tip portion 431 of the side surface protection portion 43 of the pressing surface cover 4 is inserted into the recessed portion 531 of the side surface protection portion 53 of the inner circumferential surface cover 5. In addition, the pressing surface cover 4 is attached to the coil 2 so that the extension portion 54 of the inner circumferential surface cover 5 is inserted into the notch 442 of the central extension portion 44 of the pressing surface cover 4. In the state where the pressing surface cover 4 is attached to the coil 2, the tip portion 431 does not contact the side wall 532 of the recessed portion 531, and the extension portion 54 does not contact the side wall 443 of the notch 442. Therefore, the pressing surface cover 4 can move along the winding axis. By attaching the pressing surface cover 2 to the coil 2, the pressing surface 22 is covered by the pressing surface protection portion 41 of the pressing surface cover 4.

[0062] Finally, the protrusion 34 of the upper cover 3 is inserted into the recess 412 or hole 414 of the pressing surface cover 4, and the upper cover 3 and the pressing surface cover 4 are fitted together. The upper cover 3 is not in contact with the inner peripheral surface cover 5. Therefore, by fitting the upper cover 3 and the pressing surface cover 4 together, the upper cover 3 and the pressing surface cover 4 can move in conjunction with each other.

[0063] After the cover mounting process, the process proceeds to the mold accommodation process. In the mold accommodation process, the coil 2 with the upper cover 3, the pressing surface cover 4, and the inner peripheral surface cover 5 attached is accommodated in the mold. The mold has an upper mold and a lower mold. First, the coil 2 is placed on the lower mold, and then the upper mold is pressed into the lower mold to fit the upper mold and the lower mold together. By pressing the coil 2 with the upper mold, the winding variation in the vertical direction is corrected. The upper cover 3 and the pressing surface cover 4 are accommodated in the mold so as to be movable along the winding axis. In addition, the fixing surface 23 of the coil 2 abuts against the upper mold, lower mold, or jig via the fixing surface protection portion 52 of the inner peripheral surface cover 5, and is accommodated so that the position of the fixing surface 23 does not move.

[0064] After the mold accommodation step, the process moves to the pressing step. In the pressing step, as shown in FIG. 14, the coil 2 is compressed toward the fixed surface 23 by the injection pressure of the pressing members and the resin. In this embodiment, five pressing members are used. Each pressing member is inserted into the position where the recessed portion 63 is to be formed. The pressing members are inserted into the mold until they abut against the pressing surface protection portion 41 or the connecting portion 42. Then, the coil 2 is pressed toward the fixed surface 23 by the pressing members.

[0065] Resin that constitutes the coil mold resin portion 6 is injected into the mold. A gate G into which the resin is injected is provided on a projection area of ​​the pressing surface protection portion 41 in the winding axis direction. In this embodiment, it is provided below the bulging portion 411. After molding, an injection mark M is formed at the location where the gate G is provided. The resin is injected from the gate G along the winding axis toward the pressing surface protection portion 41. That is, the coil 2 is pressed toward the fixing surface 23 by the injection pressure of the resin.

[0066] Since the fixing surface 23 is fixed via the fixing surface protection part 52, the coil 2 is compressed toward the fixing surface 23 by the injection pressure of the resin and the pressure of the pressing member (see the outline arrow in FIG. 14). Furthermore, the upper cover 3 and the pressing surface cover 4 move toward the fixing surface 23 in conjunction with the compression of the coil 2. In other words, only the pressing surface cover 4 moves, and the occurrence of a gap between the upper cover 3 and the pressing surface cover 4 is suppressed.

[0067] In this way, the length of the winding shaft of the coil 2 is pressed to the desired length by the resin injection pressure and the pressing member. In this state, the resin hardens to form the coil mold resin part 6, and the coil 2 is fixed at the desired length. Through this pressing process, the molded coil 1 is produced.

[0068] (effect) As described above, the manufacturing method for the molded coil of this embodiment includes a cover attachment step of attaching the upper cover 3, the pressing surface cover 4, and the inner peripheral surface cover 5 to the coil 2, and a pressing step of pressing the coil 2 along the winding axis by a pressing member or the injection pressure of the resin after the cover attachment step, thereby compressing the coil 2. The coil 2 has a pressing surface 22, which is one end surface perpendicular to the winding axis, that is pressed in the pressing step. The upper cover 3 has a protruding portion 34 that protrudes from one end of the upper cover 3 toward the pressing surface 22. In the pressing step, the upper cover 3 and the pressing surface cover 4 move along the winding axis as the coil is compressed.

[0069] In this way, during the pressing step, not only the pressing surface cover 4 but also the upper cover 3 moves along the winding axis in response to the compression of the coil 2. Therefore, compared to when only the pressing surface cover 4 moves, a gap is less likely to occur between the pressing surface cover 4 and the upper cover 3. This improves formability and allows the coil 2 to be compressed to a desired length.

[0070] Further, the tip portion 431 of the side protection portion 43 of the pressing surface cover 4 is inserted into the recessed portion 531 of the side protection portion 53 of the inner circumferential surface cover 5, and there is a gap S1 between the side wall 532. Further, the pressing surface cover 4 has a notch 442, and the extension portion 54 of the inner circumferential surface cover 5 is inserted into the notch 442, and there is a gap S2 between the side wall 443. In this way, the pressing surface cover 4 is configured to be movable along the winding axis without contacting the inner circumferential surface cover 5. Therefore, the pressing surface cover 4 can move according to the compression of the coil 2. Note that it is sufficient that the end faces of the pressing surface cover 4 and the inner circumferential surface cover 5 that are perpendicular to the winding axis are not in contact with each other. In other words, the pressing surface cover 4 and the inner circumferential surface cover 5 that are perpendicular to the lateral arrangement direction of the coil 2 may be in contact with each other.

[0071] The upper cover 3 and the pressing surface cover 4 are fitted together, and in the pressing process, they move in conjunction with each other in response to the compression of the coil 2. Because the upper cover 3 and the pressing surface cover 4 are fitted together, it is possible to prevent the upper cover 3 and the pressing surface cover 4 from shifting in position due to the injection pressure of the resin. For example, if the upper cover 3 and the pressing surface cover 4 are not fitted together, the position of the upper cover 3 may shift, and a gap may occur between the upper cover 3 and the pressing surface cover 4. However, by fitting the upper cover 3 and the pressing surface cover 4 together, it is possible to prevent the occurrence of a gap, and it is possible to further improve moldability.

[0072] In addition, by fitting the upper cover 3 and the pressing surface cover 4, the degree of freedom of the pressing member or the injection point of the resin increases. In other words, when the upper cover 3 and the pressing surface cover 4 are not fitted together, in order to move the upper cover 3 following the compression of the coil 2, it is necessary to press the protruding part 34 of the upper cover 3 with the injection pressure of the pressing member or the resin. On the other hand, when the upper cover 3 and the pressing surface cover 4 are fitted together, the upper cover 3 also moves following the movement of the pressing surface cover 4. Therefore, the condition of pressing the protruding part 34 of the upper cover 3 is not required, so the worker can freely select the pressing point or the injection point of the resin. In addition, when there are multiple fitting points, it is sufficient to provide at least one hole 414, but it is preferable to not provide the recessed part 412 and to make all of them holes 414.

[0073] The pressing surface cover 4 has a pressing surface protection part 41 that covers the pressing surface 22, and a hole 414 that is recessed in the upper surface of the pressing surface protection part 41, and the upper cover 3 and the pressing surface cover 4 are fitted together by inserting the protrusion 34 into the hole 414. Since the protrusion 34 is surrounded on all four sides by the side surfaces of the pressing surface cover 4, the upper cover 3 can better follow the movement of the pressing surface cover 4.

[0074] (Other embodiments) In this specification, an embodiment of the present invention has been described, but this embodiment is presented as an example and is not intended to limit the scope of the invention. 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 invention and its equivalents described in the claims, as well as in the scope and gist of the invention.

[0075] 5, the flat portion 31 and the curved portion 32 of the upper cover 3 do not extend beyond the fixed surface 23. However, as long as the upper cover 3 can move along the winding axis in conjunction with the compression of the coil 2, the flat portion 31 and the curved portion 32 may be flush with the fixed surface 23 or may protrude beyond the fixed surface 23.

[0076] In the above embodiment, the protrusion 34 of the upper cover 3 is inserted into the recess 412 or hole 414 of the pressing surface cover 4, and the upper cover 3 and the pressing surface cover 4 are fitted together, but the upper cover 3 and the pressing surface cover 4 do not have to be fitted together. For example, as shown in Fig. 15, the pressing surface protection part 41 of the pressing surface cover 4 may cover the pressing surface 22 of the coil 2, and the protrusion 34 of the upper cover 3 may cover the pressing surface protection part 41. In this case, the protrusion 34 can be pressed by a pressing member or by the injection pressure of resin, thereby moving the upper cover 3 along the winding axis.

[0077] In the above embodiment, two coils 2 are provided, but one coil or three or more coils may be provided. Also, the coils 2 do not have to be linked coils. [Explanation of symbols]

[0078] 1 Molded coil 2 Coil 21 Connecting Lines 22 Pressing surface 23 Fixed surface 24 Leader 25 Leader 3 Top cover 31 Flat area 311 Tip surface 32 Curved section 321 Tip surface 33 Connecting part 331 hole 34 Protrusion 4 Pressing surface cover 41, 41a, 41b Pressing surface protection part 411 Bulge 412 Recess 413 Meat platter 414 holes 42 Connecting part 421 holes 43 Side protection part 431 Tip 44 Central extension 441 Tip 441a Tip surface 442 Notch 443 Side wall 5 Inner cover 51 Inner peripheral surface protection part 52 Fixed surface protection part 53 Side protection part 531 Recess 532 Side wall 54 Extension 541 Tip surface 6 Coil mold resin 61 Pressing surface covering part 62 Exposed part 63 Recess 7 cores 8 Secondary molded resin part 9. Reactor M injection mark S1, S2 gap

Claims

1. A method for manufacturing a molded coil, comprising the steps of: a cover mounting step of mounting a cover around the coil; a pressing step of pressing the coil along a winding axis to compress the coil after the cover attachment step; Including, the coil has one end surface perpendicular to the winding axis, the pressing surface being pressed in the pressing step; The cover is an upper cover that covers an upper surface of the coil; a pressing surface cover that is separate from the upper cover and covers the pressing surface of the coil; having the upper cover has a protruding portion protruding from one end of the upper cover toward the pressing surface, the upper cover and the pressing surface cover move along the winding shaft in response to compression of the coil in the pressing step; A method for manufacturing a molded coil, comprising the steps of:

2. the upper cover and the pressing surface cover are fitted together and move in conjunction with each other in response to compression of the coil in the pressing step; The method for manufacturing a molded coil according to claim 1, further comprising the steps of:

3. The pressing surface cover is A pressing surface protection part that covers the pressing surface; A hole formed in an upper surface of the pressing surface protection portion; having the upper cover and the pressing surface cover are fitted together by inserting the protrusion into the hole; 3. The method for producing a molded coil according to claim 2, further comprising the steps of:

4. A method for manufacturing a reactor, comprising the step of mounting a core on the molded coil according to any one of claims 1 to 3.

5. A coil formed by winding a conductive member; A cover that covers the coil; a coil mold resin portion that integrates the coil and the cover; Equipped with the coil has a pressing surface which is one end surface perpendicular to the winding axis, The cover is an upper cover that covers an upper surface of the coil; A pressing surface cover that covers the pressing surface; having the upper cover has a protruding portion protruding from one end of the upper cover toward the pressing surface, the coil mold resin portion has a pressing surface covering portion that covers the pressing surface from above the pressing surface cover, At least one of an injection mark and a recessed portion is formed on the pressing surface covering portion; A molded coil characterized by the above.

6. The molded coil according to claim 5 ; a core including a magnetic material and to which the molded coil is attached; A reactor comprising:

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