Reactor manufacturing method

Abstract

To provide a reactor manufacturing method that can prevent resin from flowing onto the exposed surface of a coil.SOLUTION: A reactor manufacturing method includes a cover attachment step of attaching a pressing surface protection portion 61 to a pressing surface 33 of a coil 3, a coil molding step of pressing the pressing surface 33 of the coil 3 via the pressing surface protection portion 61 to compress the coil 3, and then injecting a molten coil molding resin 7, an assembly step of attaching a core 1 to a molded coil 2 to produce an assembly, and a secondary molding step of placing the assembly in a mold M and injecting the molten secondary molding resin 8. In the secondary molding step, the abutment surface of a pressing surface covering portion 71, which is perpendicular to a winding axis direction, abuts against the mold M, blocking the flow path leading to an exposed surface 34 of the coil 3.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a reactor in which the underside of a coil is exposed. [Background technology]

[0002] Reactors are used in a variety of applications, including office equipment, solar power generation systems, and automobiles. A reactor consists of a coil wound around a core made of magnetic material. A known method for manufacturing reactors involves two molding processes. First, a coil molding process is performed to create a molded coil, covering the inner and outer surfaces of the coil with coil molding resin. Next, a core is attached to the molded coil created in the coil molding process, and a secondary molding process is performed to coat the core and molded coil with secondary molding resin, fixing the core and molded coil together.

[0003] To improve the reactor's heat dissipation, the coil may have an exposed surface that is not covered by the coil molding resin or secondary molding resin. In this case, a mold is placed against the coil to block the resin flow path, forming the exposed surface. However, because directly contacting the coil with the mold could damage the coil's coating, a cover is attached around the coil and contacts the mold. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6638586 Summary of the Invention [Problem to be solved by the invention]

[0005] The coil is made by winding a single conductive material into a cylindrical shape while shifting the winding position in the direction of the winding axis. As a result, there are individual differences in the length of the coil in the direction of the winding axis. To correct this, in the coil molding process, one end face of the coil that is perpendicular to the direction of the winding axis is pressed in the direction of the winding axis. This compresses the coil and adjusts the length in the direction of the winding axis.

[0006] However, the compression length differs for each coil. On the other hand, the size of the mold accommodation space in the secondary molding process is fixed. Therefore, if the compression length is large, it will not match the size of the mold accommodation space, and a gap will occur between the coil or cover and the mold. This will prevent the resin flow path from being blocked during the secondary molding process, and there is a risk of resin flowing into the exposed surface of the coil.

[0007] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a reactor that can prevent resin from flowing into the exposed surface of the coil. [Means for solving the problem]

[0008] The method for manufacturing a reactor of the present invention is a method for forming an exposed surface on a coil, and includes a cover mounting step of mounting a pressing surface cover on the pressing surface of the coil, which is one end surface perpendicular to the winding axis direction; a coil molding step of placing the coil with the pressing surface cover mounted in a first mold and pressing the pressing surface via the pressing surface cover to compress the coil, and injecting molten coil molding resin; an assembling step of manufacturing an assembly by mounting a core on the molded coil manufactured in the coil molding step; and a step of placing the assembly in a second mold and injecting molten secondary molding resin. and a secondary molding process in which a molten coil molding resin is injected into the coil molding resin, wherein in the coil molding process, a gap corresponding to the compressed length of the coil is formed between the first mold and the pressing surface cover, and the molten coil molding resin is poured to fill the gap, causing the coil molding resin to form a pressing surface covering portion that covers the pressing surface cover, and the pressing surface covering portion has a thickness corresponding to the compressed length of the coil, and in the secondary molding process, an end face of the pressing surface covering portion that is perpendicular to the winding axis direction abuts against the second mold, blocking a flow path leading to the exposed surface of the coil. [Effects of the Invention]

[0009] According to the present invention, a method for manufacturing a reactor can be obtained that can prevent resin from flowing into the exposed surface of the coil. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view showing the main components of the reactor. [Figure 2] FIG. 10 is a diagram showing the state before various covers are attached to the coil. [Figure 3] 10A and 10B are diagrams showing the state in which various covers are attached to the coil. [Figure 4] FIG. 10 is a view of the molded coil as seen from the pressing surface side. [Figure 5] FIG. 2 is a perspective view showing the overall configuration of a reactor. [Figure 6] FIG. 2 is a view of the reactor as seen from the pressing surface side. [Figure 7] FIG. 2 is an enlarged view of the pressing surface of the coil. [Figure 8] FIG. 10 is a schematic diagram showing a state in which the assembly is housed in a mold. [Figure 9] FIG. 10 is a schematic diagram showing a state in which an assembly according to the prior art is housed in a mold; [Figure 10] 10 is a schematic diagram showing a covering state of the pressing surface of the pressing surface protection section and the pressing surface covering section in Modification 1. FIG. [Figure 11] 10 is a schematic diagram showing a covering state of the pressing surface of the pressing surface protection section and the pressing surface covering section in Modification 2. FIG. [Figure 12] 13 is a schematic diagram showing a covering state of the pressing surface of the pressing surface protector and the pressing surface covering portion in Modification 3. FIG. [Figure 13] 13 is a schematic diagram showing a covering state of the pressing surface of the pressing surface protection section and the pressing surface covering section in Modification 4. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Embodiment] [composition] A reactor according to an embodiment will be described with reference to the drawings. In the drawings, thickness, dimensions, positional relationships, ratios, shapes, etc. may be emphasized for ease of understanding, but the present invention is not limited to such emphasis. Fig. 1 is a perspective view showing the main components of a reactor 10.

[0012] Reactor 10 includes core 1 and molded coil 2. Molded coil 2 is formed by coating a portion of the periphery of coil 3 with coil mold resin 7. However, as shown in FIG. 1, the underside of coil 3 is not coated with coil mold resin 7, but is an exposed surface 34. Molded coil 2 is formed by molding. Molded coil 2 is attached to core 2. Exposed surface 34 may be the top or side surface of coil 3 instead of the bottom surface. Note that the up-down direction is based on the upper and lower molds that house coil 3 during molding, and does not refer to the positional relationship or direction when reactor 10 is mounted on an actual device to be installed.

[0013] When power is supplied to coil 2, coil 2 generates magnetic flux. Core 1 is ring-shaped and forms a closed magnetic circuit through which the magnetic flux generated by coil 3 passes. In this way, reactor 10 is an electromagnetic component that converts electrical energy into magnetic energy and stores and releases it.

[0014] The core 1 includes a magnetic material. A powder magnetic core, a ferrite core, a laminated steel plate, a metal composite core, or the like can be used as the core 1. The metal composite core is a magnetic material formed by kneading magnetic powder and resin and then hardening the resin.

[0015] The core 1 of this embodiment is made up of two U-shaped core members. Each U-shaped member has a pair of legs and a yoke that connects the legs. By joining the legs of the two U-shaped members, the core 1 becomes ring-shaped.

[0016] A spacer may be provided between the joint surfaces of each leg. That is, the two U-shaped members may be joined via a spacer. The spacer provides a magnetic gap of a predetermined width to prevent a decrease in the inductance of the reactor. 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. Alternatively, an air gap may be provided without using a spacer.

[0017] Coil 3 is composed of a single conductive member that is insulated with enamel or the like. Coil 3 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, and coil 3 is an edgewise coil in which the wide surface of the conductive member extends in a direction perpendicular to the winding axis of coil 3. Coil 3 may also be a flatwise coil. Alternatively, round wire may be used as the conductive member.

[0018] Two coils 3 are provided. The two coils 3 are arranged with their sides facing each other so that their winding axes are parallel. The coils 3 have lead wires 31 that are connected to a bus bar (not shown) by welding or the like. The bus bar is electrically connected to an external device, and power is supplied to the coils 3 via the bus bar.

[0019] FIG. 2 shows the coil 3 before the various covers 4, 5, and 6 are attached. FIG. 3 shows the coil 3 after the various covers 4, 5, and 6 have been attached. As shown in FIGS. 2 and 3, the coil 3 has a fixing surface 32 and a pressing surface 33, which are a pair of annular surfaces that are end faces perpendicular to the winding axis. The fixing surface 32 is a surface that is fixed by a mold or the like to prevent misalignment in the coil molding process described below. The pressing surface 33 is a surface that is pressed in the winding axis direction to compress the coil 3 in the coil molding process.

[0020] 2 and 3, a top cover 4, a fixed surface cover 5, and a pressing surface cover 6 are attached around the coil 3. The top cover 4, the fixed surface cover 5, and the pressing surface cover 6 prevent the mold, the pressing member, and the injected resin from coming into direct contact with the coil 3 during molding.

[0021] The top cover 4, the fixed surface cover 5, and the pressing surface cover 6 are made of resin. Examples of types of resin include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), and PBT (Polybutylene Terephthalate). As shown in FIG. 2, the top cover 4, the fixed surface cover 5, and the pressing surface cover 6 are molded as separate bodies.

[0022] The top cover 4 is placed on the top surface of the coil 3. The top cover 4 has a pair of top protective portions 41 and a connecting portion 42. The top protective portions 41 cover the top surface of each coil 3. The top protective portions 41 extend from the pressing surface 33 side toward the fixed surface 32 side, but expose the edge 35 of the top surface of the coil 3 on the fixed surface 32 side (see Figure 3). In other words, the top protective portions 41 are slightly shorter than the top surface of the coil 3 and do not interfere with the fixed surface cover 5. When the top surface of the coil 3 is pressed with a mold to correct unevenness on the top surface of the coil 3, the top protective portions 41 are interposed between the mold and the top surface of the coil 3 to protect the top surface of the coil 3.

[0023] The connecting portion 42 connects the pair of upper surface protection portions 41. The pair of upper surface protection portions 41 and the connecting portion 42 are integrally molded products that are connected continuously without any seams.

[0024] The fixed surface cover 5 covers the fixed surface 32 of the coil 3. Two fixed surface covers 5 are provided. Each fixed surface cover 5 has a fixed surface protective portion 51, an inner peripheral surface protective portion 52, and an outer surface protective portion 53. The fixed surface protective portion 51, the inner peripheral surface protective portion 52, and the outer surface protective portion 53 are integrally molded products that are connected together seamlessly. Note that the two fixed surface covers 5 are configured as separate bodies, but they may also be formed as an integrally molded product by providing a connecting portion or the like between each fixed surface protective portion 51.

[0025] The fixing surface protection part 51 is a ring-shaped plate having an opening of the same shape and size as the opening of the fixing surface 32, and covers the fixing surface 32 of the coil 3. The inner peripheral surface protection part 52 is a cylinder whose shape follows the inner peripheral surface of the coil 3. The inner peripheral surface protection part 52 extends from the fixing surface protection part 51 along the winding axis toward the pressing surface 33. The inner peripheral surface protection part 52 is inserted into the inner periphery of the coil 3 and covers the inner peripheral surface of the coil 3.

[0026] The outer surface protection portion 53 covers the outer surface 37 of the coil 3. The outer surface protection portion 53 is a plate-shaped member that extends from the edge of the fixing surface covering portion 51 along the winding axis toward the pressing surface 33. However, the outer surface protection portion 53 does not reach the pressing surface 33. The outer surface protection portion 53 covers the outer surface 37 of the coil 3. The side surfaces of the coil 3 are end surfaces that are perpendicular to the arrangement direction of the coils 3, and the side surface that each coil 3 faces is called the inner surface 36, and the side surface opposite the inner surface 36 is called the outer surface 37. The outer surface protection portion 53 has a pocket portion 531 in which the outer surface protection portion 62 of the pressing surface cover 6, which will be described later, is stored. The inside of the pocket portion 531 is a space in which the outer surface protection portion 62 is stored.

[0027] The pressing surface cover 6 covers the pressing surface 33 of the coil 3. The pressing surface cover 6 has a pressing surface protection portion 61, an outer surface protection portion 62, and an inner surface protection portion 63. The pressing surface protection portion 61, the outer surface protection portion 62, and the inner surface protection portion 63 are a seamless, integrally molded product. The pressing surface protection portion 61 is a ring-shaped plate with an opening of the same shape and size as the opening of the pressing surface 33, and covers the pressing surface 33 of the coil 3. The pressing surface protection portion 61 covers the entire pressing surface 33 of the coil 3, and the lower surface of the pressing surface protection portion 61 is flush with the exposed surface 34 of the coil 3. During coil molding, the pressing surface 33 of the coil 3 is pressed via the pressing surface protection portion 61.

[0028] The outer surface protection portion 62 is a plate-shaped member that extends from the edge of the pressing surface protection portion 61 along the winding axis toward the fixed surface 32. The outer surface protection portion 62 extends beyond the tip of the outer surface protection portion 53 of the fixed surface cover 5 toward the fixed surface 32, but does not reach the fixed surface 32. The outer surface protection portion 62 is stored in the space in the pocket portion 531 of the outer surface protection portion 53. In other words, the outer surface protection portion 62 of the pressing surface cover 6 does not interfere with the outer surface protection portion 53 of the fixed surface cover 5. Therefore, the pressing surface cover 6 can move toward the fixed surface 32 in response to compression of the coil 3 during molding.

[0029] The inner surface protection portion 63 is a plate-shaped member and is disposed between the coils 3. The inner surface protection portion 63 extends from the pressing surface protection portion 61 along the winding axis toward the fixed surface 32. The inner peripheral surface protection portion 63 does not interfere with the fixed surface cover 5. The inner surface protection portion 63 covers the inner surface 36 of the coil 3.

[0030] 1, the coil mold resin 7 covers the coil 3, the upper surface cover 4, the fixed surface cover 5, and part of the pressing surface cover 6. The lower surface of the coil 3 is not covered by the coil mold resin 7 and is exposed.

[0031] The coil mold resin 7 is made of resin. Examples of the resin include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), and PBT (Polybutylene Terephthalate). These resins may also contain thermally conductive fillers. The coil mold resin 7 is formed by placing the coil 3 in a mold, injecting molten resin into the mold, and allowing the injected resin to solidify.

[0032] FIG. 4 is a view of the molded coil 2 as viewed from the pressing surface 33 side. The coil mold resin 7 has a pressing surface covering portion 71. The pressing surface covering portion 71 covers the pressing surface 33 of the coil 3 via the pressing surface protection portion 61. However, the pressing surface covering portion 71 exposes the lower end of the pressing surface protection portion 61. In other words, the pressing surface protection portion 61 has an exposed portion 611 that is not covered by the pressing surface covering portion 71. The exposed portion 611 extends over the entire lower end of the pressing surface protection portion 61. The boundary between the pressing surface covering portion 71 and the exposed portion 611 is stepped (see FIGS. 7 and 8). Note that the pressing surface covering portion 71 may cover the lower end of the pressing surface protection portion 61 without forming the exposed portion 611 (see FIG. 10).

[0033] The thickness of the pressing surface covering portion 71 depends on the compressed length of the coil 3 in the coil molding process described below. Specifically, during the coil molding process, the thickness is the sum of the length between the mold and the pressing surface cover 6 when the coil 3 is housed in the mold and the compressed length of the coil 3. In other words, if the compressed length of the coil 3 is long, the thickness of the pressing surface covering portion 71 will be thick, and if the compressed length of the coil 3 is short, the thickness of the pressing surface covering portion 71 will be thin. The thickness of the pressing surface covering portion 71 is the length in the direction of the winding axis of the coil 3.

[0034] The pressing surface cover 71 has a plurality of holes 711 formed therein, which are marks formed when the pressing surface protection portion 61 is pressed with a pressing member or the like during coil molding. The holes 711 are formed to match the shape of the pressing member or the like, such as a circular or rectangular shape. The pressing surface protection portion 61 or the coil 3 is exposed through the holes 711.

[0035] Fig. 5 is a perspective view showing the overall configuration of reactor 10. As shown in Fig. 5, core 1 and molded coil 2 are covered with secondary molded resin 8. Core 1 and molded coil 2 are fixed in place by secondary molded resin 8. Secondary molded resin 8 is formed by placing core 1 with molded coil 2 attached in mold M, injecting molten resin into mold M, and allowing the injected resin to solidify (see Fig. 8).

[0036] Secondary molding resin 8 is made of resin. Examples of the resin include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), and PBT (Polybutylene Terephthalate). These resins may also contain thermally conductive fillers.

[0037] FIG. 6 is a view of reactor 10 viewed from the pressing surface 33 side. Secondary molded resin 8 has a covering portion 81 that covers pressing surface covering portion 71 of coil molded resin 7. However, covering portion 81 exposes the lower end of pressing surface covering portion 71. In other words, pressing surface covering portion 71 has an exposed portion 712 that is not covered by covering portion 81. Exposed portion 712 extends over the entire lower end of pressing surface covering portion 71. The boundary between covering portion 81 and exposed portion 712 is a step, as shown in FIG. 7.

[0038] [Manufacturing method] Next, a description will be given of a method for manufacturing the reactor 10 of this embodiment. The method for manufacturing the reactor 10 includes a cover mounting step, a coil molding step, an assembly step, and a secondary molding step.

[0039] The cover attachment process is a process of attaching the top cover 4, the fixed surface cover 5, and the pressing surface cover 6 to the coil 3. First, the inner circumferential surface protection portion 52 of each fixed surface cover 5 is inserted into the inner periphery of each coil 3. Once the insertion is complete, the fixed surface protection portion 52 abuts against the fixed surface 32 of the coil 3, covering the fixed surface 32.

[0040] Next, the top cover 4 is attached so that each top protection part 41 covers the top surface of each of the two coils 3. At this time, the top protection part 41 exposes the edge of the top surface of the coil 3 on the fixing surface 32 side, and does not interfere with the fixing surface cover 5.

[0041] Finally, the pressing surface cover 6 is attached to the pressing surface 33 of the coil 3. The outer surface protection portion 62 of the pressing surface cover 6 is stored in the pocket portion 531 of the outer surface protection portion 53 of the fixed surface cover 5. Therefore, the pressing surface cover 6 does not interfere with the fixed surface cover 5. Note that when the pressing surface protection portion 61 is in contact with the pressing surface 33 of the coil 3, there is a gap between the tip surface of the outer surface protection portion 62 of the pressing surface cover 6 and the pocket portion 531, so the pressing surface cover 6 can move in the winding axis direction as the coil 3 is compressed.

[0042] The coil molding process is a process in which coil molding resin 7 is formed around the coil 3 by molding. First, the coil 3 fitted with various covers 4, 5, and 6 is placed in a mold. The fixing surface protection portion 51 of the coil 3 placed in the mold abuts against the mold and is fixed so as not to shift position. The mold used in the coil molding process corresponds to the first mold in the claims.

[0043] Then, the pressing surface 33 is pressed by a pressing member or the like via the pressing surface protection portion 61. The pressing surface cover 6 and the top cover 4 are movable in the winding axis direction because they do not interfere with the fixed surface cover 5. Therefore, the pressing surface cover 6 and the top cover 4 move toward the fixed surface 32 in response to the compression of the coil 3.

[0044] When the coil 3 is compressed, a gap is provided between the pressing surface protection part 61 and the mold so that the pressing surface covering part 71 can be formed. This gap may be formed by compressing the coil 3, with the pressing surface protection part 61 and the mold being in contact before the coil 3 is compressed, or it may be formed before the coil 3 is compressed and then enlarged by compressing the coil 3. A slide or the like is in contact with the exposed part 621 of the pressing surface protection part 61, and the slide is moved in response to the compression of the coil 3, so that the coil mold resin 7 is not formed on the exposed surface 621.

[0045] With the coil 3 in a compressed state, molten resin is injected into the mold. The resin may be injected toward the pressing surface 33. In this case, the coil 3 can also be pressed by the resin injection pressure. A predetermined amount of resin is injected and then solidified to form the coil mold resin 7. The coil 3 is maintained in a compressed state by the coil mold resin 7. The pressing surface covering portion 71 is then formed with a thickness corresponding to the compressed length of the coil 3. The molded coil 2 is produced through the coil molding process.

[0046] The assembly process is a process for producing an assembly in which the molded coil 2 is attached to the core 1. Two U-shaped members are inserted into the inner circumference of the molded coil 2, and the legs are joined together to produce an assembly in which the molded coil 2 is attached to the annular core 1.

[0047] The secondary molding process is a process in which secondary molded resin 8 is formed around the assembly by molding. The assembly is placed inside mold M. FIG. 8 is a schematic diagram showing the assembly placed inside mold M. As shown in FIG. 8, mold M abuts against pressing surface covering portion 71. Specifically, mold M abuts against the end face of pressing surface covering portion 71 that is perpendicular to the winding axis (hereinafter, the portion of the end face of pressing surface covering portion 71 that is perpendicular to the winding axis and abuts against mold M will also be referred to as the "abutment surface"). Pressing surface covering portion 71 has a thickness corresponding to the compressed length of coil 3, so that the abutment surface of pressing surface covering portion 71 can abut against mold M. In other words, the flow path toward exposed surface 34 of coil 3 is blocked by the abutment surface of pressing surface covering portion 71 and mold M. This abutment surface becomes exposed portion 712 that is exposed from secondary molded resin 8 after the secondary molding process is completed. The mold M used in the secondary molding step corresponds to the second mold in the claims.

[0048] 9 is a schematic diagram showing a state in which an assembly according to the prior art is housed in a mold M. As shown in FIG. 9, in the coil molding process, the pressing surface protection portion 61 of the pressing surface cover 6 moves in position as the coil 3 is compressed. Therefore, if the pressing surface covering portion 71 is not formed, a gap S will be generated between the pressing surface protection portion 61 and the mold M in the secondary molding process, and the flow path of the resin toward the exposed surface 34 of the coil 3 will not be blocked. In particular, since the compressed length of the coil 3 differs depending on the individual coil 3, adjusting it using the mold M in the secondary molding process is not realistic from the standpoint of cost and productivity.

[0049] Therefore, in this embodiment, a pressing surface covering portion 71 is formed to cover the pressing surface protection portion 61, and the pressing surface covering portion 71 is formed to a thickness according to the compressed length of the coil 3. Therefore, during the secondary molding process, the contact surface of the pressing surface covering portion 71 contacts the mold M, blocking the flow path of the resin toward the exposed surface 34.

[0050] Furthermore, a part of the lower surface of the pressing surface protection portion 71 abuts against the mold M, and the exposed surface 34 of the coil 3 does not abut against the mold M, and a gap is formed between the mold M and the exposed surface 34 of the coil 3. Therefore, molding can be performed in a state where the mold M is not in contact with the exposed surface 34 of the coil 3.

[0051] In this way, molten resin is injected into the mold M while the mold M is in contact with the contact surface and the underside of the pressing surface covering portion 71. The gate from which the resin is injected is, for example, above the yoke portion of the core 1. The resin injected from the gate flows downward, i.e., toward the exposed surface 34 of the coil 3, as shown by the black arrow in FIG.

[0052] However, because the flow path is blocked by the contact surface of pressing surface covering portion 71 and mold M, the resin that reaches that point is blocked and cannot flow any further toward exposed surface 34. Furthermore, even if resin does enter between the contact surface of pressing surface covering portion 71 and mold M, the underside of pressing surface covering portion 71 and mold M are in contact, so the resin is prevented from flowing toward exposed surface 34 of coil 3. Then, by solidifying the resin injected into mold M, secondary molded resin 8 is formed and reactor 10 is produced.

[0053] [effect] As described above, the manufacturing method of reactor 10 of this embodiment includes a cover attachment step of attaching pressing surface protective portion 61 to pressing surface 33 of coil 3, which is one end surface perpendicular to the winding axis direction; a coil molding step of placing coil 3 with pressing surface protective portion 61 attached in a mold and compressing coil 3 by pressing pressing surface 33 via pressing surface protective portion 61, and injecting molten coil mold resin 7; an assembly step of attaching core 1 to the molded coil produced in the coil molding step to produce an assembly; and a secondary molding step of placing the assembly in mold M and injecting molten secondary mold resin 8. An exposed surface 34 is formed in coil 3. In the coil molding step, a pressing surface covering portion 71 that covers pressing surface protective portion 61 is formed in coil mold resin 7, and the pressing surface covering portion 71 has a thickness corresponding to the compressed length of the coil. In the secondary molding step, the end face of the pressing surface covering portion 71 perpendicular to the winding axis direction abuts against the mold M, blocking the flow path leading to the exposed surface 34 of the coil 3.

[0054] In this way, in the coil molding process, the pressing surface covering portion 71 is formed to a thickness corresponding to the compressed length of the coil 3, so that in the secondary molding process, the contact surface of the pressing surface covering portion 71 can be brought into contact with the mold M. This blocks the flow path toward the exposed surface of the coil 3, preventing resin from flowing onto the exposed surface 34 of the coil 3, making it possible to manufacture a reactor 10 with excellent heat dissipation effect.

[0055] In the coil molding process, the pressing surface covering portion 71 exposes a portion of the exposed surface 34 side of the pressing surface protection portion 61, and in the secondary molding process, the end surface of the pressing surface covering portion 71 perpendicular to the winding axis direction and the underside of the pressing surface covering portion 71 abut against the mold M, and a gap is formed between the mold M and the exposed surface 34 of the coil 3, so that they are not in contact.

[0056] This allows not only the contact surface of the pressing surface covering portion 71 but also the underside of the pressing surface covering portion 71 to come into contact with the mold M, thereby more accurately blocking the flow path leading to the exposed surface 34. Furthermore, since the mold M does not come into direct contact with the exposed surface 34 of the coil 3, damage to the coating of the coil 3 can be suppressed.

[0057] 10 is a schematic diagram showing the covering state of the pressing surface of the pressing surface protection portion and the pressing surface covering portion in Modification 1. As shown in FIG. 10, the entire pressing surface protection portion 61 may be covered by the pressing surface covering portion 71. That is, the exposed surface 34 of the coil 3, the lower surface of the pressing surface protection portion 61, and the lower surface of the pressing surface covering portion 71 may be flush with each other. However, when the lower surface of the pressing surface covering portion 71 is brought into contact with the mold M during the secondary molding process, the exposed surface 34 of the coil 3 also comes into contact with the mold M. This may result in damage to the coating of the coil 3.

[0058] 8 , when the exposed portion 611 is provided in the pressing surface protection portion 61, a space is formed below the pressing surface covering portion 71. By inserting the mold M into this space, the mold M can be brought into contact with the lower surface of the pressing surface covering portion 71, and a gap can be formed between the mold M and the exposed surface 34 of the coil 3. This makes it possible to more effectively prevent the resin from flowing onto the exposed surface 34 of the coil 3 without damaging the exposed surface 34.

[0059] Fig. 11 is a schematic diagram showing the covering state of the pressing surface of the pressing surface protector and pressing surface cover in Modification 2. As shown in Fig. 11, the pressing surface protector 61 and the pressing surface cover 71 may be configured to protrude beyond the exposed surface 34 of the coil 3, that is, the exposed surface 34 and the lower surfaces of the pressing surface protector 61 and the pressing surface cover 71 may not be flush with each other. In this case, the exposed surface 34 does not come into contact with the mold M, and therefore damage to the exposed surface 34 can be prevented.

[0060] However, in the embodiment of FIG. 11, if secondary molded resin 8 flows between the contact surface and the underside of mold M and pressing surface covering portion 71, there is a risk of burrs forming toward exposed surface 34. On the other hand, by configuring pressing surface protection portion 61 to have exposed portion 611 as in the embodiment of FIG. 8, even if burrs do form, they form on the underside of pressing surface covering portion 71, preventing burrs from forming on exposed surface 34. This makes it possible to manufacture reactor 10 with excellent heat dissipation properties. Furthermore, the amounts of coil molded resin 7 and secondary molded resin 8 used can be reduced, resulting in cost savings.

[0061] FIG. 12 is a schematic diagram showing the covering state of the pressing surface of the pressing surface protector and the pressing surface covering portion in Modification 3. FIG. 13 is a schematic diagram showing the covering state of the pressing surface of the pressing surface protector and the pressing surface covering portion in Modification 4. As shown in FIGS. 12 and 13, only one of the pressing surface protector 61 and the pressing surface covering portion 71 may protrude beyond the exposed surface 34 of the coil 3. That is, as shown in FIG. 12, only the pressing surface protector 61 may protrude beyond the exposed surface 34, or as shown in FIG. 13, only the pressing surface covering portion 71 may protrude beyond the exposed surface 34. In particular, the configuration shown in FIG. 13, in which the pressing surface covering portion 71 protrudes and remains on the lower surface of the pressing surface protector 61 even if burrs are generated, is preferable. Even with these configurations, contact between the exposed surface 34 of the coil 3 and the mold M can be prevented. However, even in the cases of FIGS. 12 and 13, the amounts of coil mold resin 7 and secondary mold resin 8 used increase, so the configuration of the embodiment shown in FIG. 8 is more preferable in terms of cost.

[0062] [Other embodiments] Although the present specification describes an embodiment of the present invention, this embodiment is presented as an example and is not intended to limit the scope of the invention. The above-described embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. The embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. [Explanation of symbols]

[0063] 10 Reactor 1 core 2 Molded coil 3 coils 31 Leader 32 Fixed surface 33 Pressing surface 34 Exposed surface 35 En 36 Inner surface 37 External surface 4 Top cover 41 Top protection part 42 Connecting part 5 Fixed surface cover 51 Fixed surface protection part 52 Inner peripheral surface protection part 53 Outer protection part 531 Pocket 6 Pressing surface cover 61 Pressing surface protection part 611 Exposed part 62 Outer side protection part 63 Inner side protection part 7 Coil mold resin 71 Pressing surface covering part 711 hole 712 Exposed part 8 Secondary molding resin 81 Covering part M mold S Gap

Claims

1. A method for manufacturing a reactor that forms an exposed surface on a coil, a cover attachment step of attaching a pressing surface cover to a pressing surface of the coil, the pressing surface being one end surface perpendicular to the winding axis direction; a coil molding process of housing the coil with the pressing surface cover attached in a first mold, and injecting molten coil molding resin into the first mold while the coil is compressed by pressing the pressing surface through the pressing surface cover; an assembly process in which a core is attached to the molded coil produced in the coil molding process to produce an assembly; a secondary molding step of placing the assembly in a second mold and injecting molten secondary molding resin; Including, In the coil molding process, a gap corresponding to the compressed length of the coil is formed between the first mold and the pressing surface cover, and the molten coil molding resin is poured to fill the gap, and a pressing surface covering portion that covers the pressing surface cover is formed in the coil molding resin, and the pressing surface covering portion has a thickness corresponding to the compressed length of the coil, in the secondary molding step, an end face of the pressing surface covering portion perpendicular to the winding axis direction abuts against the second mold to block a flow path leading to an exposed surface of the coil; A method for manufacturing a reactor, comprising:

2. In the coil molding step, the pressing surface covering portion exposes a part of the exposed surface side of the pressing surface cover, in the secondary molding step, an end face of the pressing surface covering portion perpendicular to the winding axis direction and a lower face of the pressing surface covering portion are brought into contact with the second mold, and the second mold and an exposed surface of the coil are not in contact with each other; 2. The method for manufacturing a reactor according to claim 1,

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