Reactor manufacturing method

Abstract

To provide a manufacturing method of a reactor capable of suppressing crack of a core caused by a resin pressure during molding of a secondary mold resin.SOLUTION: A manufacturing method of a reactor includes the steps of: preparing a pair of cores 10 each having a U-shaped recess 14 and a mold coil 21 in which a cylindrical coil C1 is covered by a primary mold resin R1; assembling the pair of cores 10 and the mold coil 21 by abutting the pair of cores 10 while fitting the mold coil 21 into the recesses 14; and injecting a secondary mold resin R2 to the pair of cores 10 and the mold coils 21 which are assembled. In the prepared mold coil 21, an entire outer side face opposed to the recesses 14 of the pair of cores 10 is not covered by the primary mold resin R1 and the coil C1 is exposed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a reactor. [Background technology]

[0002] A reactor is known in which a core is assembled to a coil, and the coil-core assembly is covered with resin. For example, Patent Document 1 discloses a method for manufacturing a reactor including a primary molding step and a secondary molding step, in which a common mold can be used for both the primary molding and the secondary molding when manufacturing the reactor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-149841 Summary of the Invention [Problem to be solved by the invention]

[0004] In the reactor manufacturing method disclosed in the above-mentioned Patent Document 1, when the secondary molded resin is formed, the resin preferentially enters the outer periphery of the core having a U-shaped recess, and the pressure (resin pressure) acting on the core from the outer periphery increases due to the resin, which may cause cracks in the core.

[0005] The present disclosure has been made in consideration of the above circumstances, and provides a method for manufacturing a reactor that can prevent the core from cracking due to the resin pressure when forming the secondary molding resin. [Means for solving the problem]

[0006] A method for manufacturing a reactor according to the present disclosure includes: A step of preparing a pair of cores having U-shaped recesses and a molded coil in which a cylindrical coil is covered with a primary molding resin; a step of butting the pair of cores together while fitting the molded coil into the recess, and assembling the pair of cores and the molded coil; and injecting a secondary molding resin into the assembled pair of cores and the molded coil, In the injecting step, the secondary molding resin is filled into a gap between the recesses of the pair of cores and the coil, The prepared molded coil is characterized in that the entire outer surface of the pair of cores facing the recesses is not covered with the primary molding resin, and the coil is exposed.

[0007] In the reactor manufacturing method according to the present disclosure, the entire outer surface of the molded coil facing the recesses of the pair of cores is not covered with the primary molding resin, leaving the coil exposed. Therefore, when the secondary molding resin is injected into the core and molded coil, the resin fills preferentially toward the inner periphery of the core rather than the outer periphery, making it possible to support the resin pressure during molding of the secondary molding resin from the inside and preventing the core from cracking.

[0008] In the prepared molded coil, more than half of the end faces of the pair of cores facing the recesses may be uncovered with the primary molding resin, leaving the coil exposed. With this configuration, resin fills the inner periphery of the core preferentially over the outer periphery, making it possible to support the resin pressure during molding of the secondary molding resin from the inside and preventing the core from cracking.

[0009] In the injection step, the core may be supported from the outside. With this configuration, the secondary molding resin filled on the inner periphery of the core can suppress the resin pressure acting from the inside to the outside of the core, thereby preventing the core from cracking.

[0010] A step of preparing a pair of cores having U-shaped recesses and a molded coil in which a cylindrical coil is covered with a primary molding resin; a step of butting the pair of cores together while fitting the molded coil into the recess, and assembling the pair of cores and the molded coil; and injecting a secondary molding resin into the assembled pair of cores and the molded coil, In the injecting step, the secondary molding resin is filled into a gap between the recesses of the pair of cores and the coil, The prepared molded coil is characterized in that more than half of the end faces of the pair of cores facing the recesses are not covered with the primary molding resin, and the coil is exposed.

[0011] In the reactor manufacturing method according to the present disclosure, more than half of the end faces of the molded coils facing the recesses of the pair of cores are not covered with the primary molding resin, leaving the coils exposed. As a result, when the secondary molding resin is injected into the cores and molded coils, the resin fills the inner periphery of the core preferentially over the outer periphery, making it possible to support the resin pressure during molding of the secondary molding resin from the inside and preventing the core from cracking. [Effects of the Invention]

[0012] The present disclosure can provide a method for manufacturing a reactor that can prevent the core from cracking due to the resin pressure when forming the secondary molding resin. [Brief explanation of the drawings]

[0013] [Figure 1] 3 is a conceptual diagram of a method for manufacturing the reactor according to the first embodiment. FIG. [Figure 2] 2 is a plan view of a core used in the method for manufacturing the reactor according to the first embodiment. FIG. [Figure 3] 2 is a vertical cross-sectional view passing through an opening N1 of the reactor 41 according to the first embodiment. FIG. [Figure 4] 2 is a vertical cross-sectional view passing through an opening N2 of the reactor 41 according to the first embodiment. FIG. [Figure 5] 4 is a cross-sectional view showing the internal state of a mold 15 used in the method for manufacturing a reactor 41 according to the first embodiment, that is, showing a manufactured reactor 41. FIG. [Figure 6] 10A and 10B are diagrams illustrating a molded coil 20 used in a method for manufacturing a reactor according to a comparative example. [Figure 7] 10 is a vertical cross-sectional view taken along a line passing through a hole h1 of a reactor 40 according to a comparative example. FIG. [Figure 8] 10 is a vertical cross-sectional view passing through an opening N3 of a reactor 40 according to a comparative example. FIG. [Figure 9] 4 is a cross-sectional view showing the internal state of a mold 25 used in a method for manufacturing a reactor 40 according to a comparative example, that is, showing a manufactured reactor 40. FIG. [Figure 10] 5A to 5C are schematic diagrams showing three cracking modes of a core 10 used in a manufacturing method of a reactor 40 according to a comparative example. [Figure 11] 10A and 10B are diagrams showing the inside and outside of a mold 35 used in a method for manufacturing a reactor according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] (Embodiment 1) <Reactor manufacturing method> Hereinafter, a method for manufacturing a reactor according to embodiment 1 will be described with reference to the drawings. In each drawing, the same or corresponding elements are denoted by the same reference numerals, and for clarity of explanation, duplicate explanations will be omitted as necessary. Also, some reference numerals will be omitted to avoid cluttering the drawings. Naturally, the right-handed xyz Cartesian coordinate system shown in the drawings is for the convenience of explaining the positional relationships of the components. Normally, the positive direction of the z axis is vertically upward, and the xy plane is the horizontal plane.

[0015] FIG. 1 is a conceptual diagram of a method for manufacturing a reactor according to the first embodiment. First, as shown in FIG. 1, a pair of cores 10 each having a U-shaped recess 14 and a molded coil 21 in which a cylindrical coil C1 is covered with a primary molding resin R1 are prepared. Next, as shown in FIG. 1, the pair of cores 10 are butted together while the molded coil 21 is fitted into the recess 14 of the core 10, and the core 10 and the molded coil 21 are assembled together. Then, injection molding is performed so that the assembled core 10 and molded coil 21 are covered with secondary molding resin R2. Through the above steps, the reactor is manufactured.

[0016] Here, referring to Fig. 1, a molded coil 21 according to the first embodiment will be described. The molded coil 21 is composed of a coil C1 and a primary molding resin R1 that covers the surfaces (outer surface, inner surface, and both end surfaces) of the coil C1. The coil C1 is a cylindrical conductive member as a whole, and is formed by edgewise winding a rectangular wire. In other words, the coil C1 is formed by laminating a rectangular wire in the x-axis direction in Fig. 1.

[0017] 1, the entire outer surface of molded coil 21 facing recesses 14 of paired cores 10 is not covered with primary molding resin R1, exposing coil C1. Also, more than half of the end surfaces of molded coil 21 facing recesses 14 of paired cores is not covered with primary molding resin R1, exposing coil C1. Furthermore, although not particularly limited, in the example shown in FIG. 1, the central portion of the top surface of molded coil 21 in the left-right direction (y-axis direction) is not covered with primary molding resin R1, exposing coil C1.

[0018] In FIG. 1, half or more of the end faces of molded coil 21 that face recesses 14 of the pair of cores may be covered with primary molding resin R1. Furthermore, in FIG. 1, a part of the outer surface of molded coil 21 that faces recessed portions 14 of the pair of cores may be covered with primary molding resin R1.

[0019] Referring to Fig. 1, the portion of molded coil 21 not covered by primary molded resin R1 in the reactor manufacturing method of embodiment 1, i.e., the exposed portion of coil C1, will be described in more detail. Here, the end face of molded coil 21 facing recessed portions 14 of the pair of cores is not covered by primary molded resin R1 and has an opening N1 through which coil C1 is exposed. In the example shown in Fig. 1, in addition to opening N1, a hole h1 is formed in the vertical center of the end face, but the hole h1 does not necessarily have to be formed.

[0020] In the example shown in Fig. 1, two openings N1 are formed, one above the other, on the end face of the pair of cores facing the recesses 14, but this is not necessarily limited to this. One or three or more openings N1 may be formed on the end face. Furthermore, as shown in Fig. 1, the area of the openings N1 and holes h1 that are not covered by the primary molding resin R1 occupies more than half of the area of the end face of the pair of cores facing the recesses 14.

[0021] 1, the entire outer surface of molded coil 21 facing recesses 14 of the pair of cores is not covered with primary molding resin R1, and coil C1 is exposed. That is, openings N2 are formed on the entire outer surface of molded coil 21 facing recesses 14 of the pair of cores. Here, "entire" does not necessarily mean 100%, and preferably includes 90% or more.

[0022] In the molded coil 21, the holes h1, the openings N1, and the openings N2 are provided at positions that are symmetrical with respect to a plane that includes the central axis of the coil C1 parallel to the xz plane. Therefore, in the example shown in Fig. 1, the molded coil 21 is provided with four holes h1, eight openings N1, and two openings N2.

[0023] Openings N1 and N2 are formed by injecting primary molding resin R1 onto coil C1 while a mold having a shape corresponding to openings N1 and N2 is brought into contact with coil C1. At this time, the contact surface between the mold having a shape corresponding to openings N1 and N2 and coil C1 is not filled with primary molding resin R1, so openings N1 and N2 are formed.

[0024] The primary molding resin R1 is not limited to being molded in a mold together with the coil C1, but may be molded separately from the coil C1. For example, the primary molding resin R1 may be injection molded separately from the coil C1 and then assembled to the coil C1.

[0025] Fig. 2 is a plan view of a core used in the method for manufacturing the reactor according to embodiment 1. Fig. 2 shows a pair of cores 10 with their surfaces, on which recesses 14 are formed, butted together. The core 10 includes a base portion 11, a center leg portion 12, outer leg portions 13a and 13b, and two recesses 14. The pair of cores 10 are configured symmetrically with respect to the butted surface parallel to the yz plane. The center legs 12 and the outer legs 13a and 13b of the pair of cores 10 that are butted together are not in close contact with each other, and gaps are generated therebetween.

[0026] As shown in FIG. 2, the base portion 11 includes a connection portion 11a that connects the middle leg portion 12 and the outer leg portion 13a, and a connection portion 11b that connects the middle leg portion 12 and the outer leg portion 13b.

[0027] As shown in Fig. 2, the center leg 12 and the outer legs 13a and 13b protrude in the same direction (x-axis direction) from the base 11. In Fig. 2, the y-axis direction is the longitudinal direction of the base 11 and the center leg 12, and the x-axis direction is the longitudinal direction of the outer legs 13a and 13b.

[0028] As shown in FIG. 2, one recess 14 is surrounded by the center leg 12, the outer leg 13a, and the connecting portion 11a, and has a U-shape in the xy plane. Similarly, the other recess 14 is surrounded by the center leg 12, the outer leg 13b, and the connecting portion 11b, and has a U-shape in the xy plane. The core 10 has two U-shaped recesses 14 arranged in the left-right direction (y-axis direction), and therefore has an E-shape in the xy plane. When a pair of cores 10 are butted together, a rectangular space is formed in the xy plane, surrounded by the recesses 14 of the pair of cores 10. Therefore, a molded coil 21 can be fitted into the recess 14 of the core 10.

[0029] The core 10 has a predetermined thickness in the z-axis direction. The thickness of the core 10 is smaller than the inner diameter of the coil C1 in FIG. 1 in the z-axis direction. Therefore, when the molded coil 21 is assembled to the core 10, the center leg 12 is stored inside the molded coil 21. On the other hand, the outer legs 13a and 13b are arranged outside the molded coil 21.

[0030] 3 is a vertical cross-sectional view of reactor 41 according to embodiment 1, taken along a plane parallel to the xz plane and passing through opening N1. Reactor 41 is composed of core 10, molded coil 21, and secondary molded resin R2 that covers core 10 and molded coil 21. When secondary molded resin R2 is injection-molded onto molded coil 21 and core 10, molded coil 21 has opening N1 with dimension W1 in the height direction (z-axis direction) and hole h1 with dimension W3 in the height direction (z-axis direction), and therefore secondary molded resin R2 fills the gap between core 10 and coil C1 through opening N1 and hole h1.

[0031] Fig. 4 is a vertical cross-sectional view passing through opening N2 of reactor 41 according to embodiment 1. That is, Fig. 4 is a cross-sectional view of reactor 41 on a plane parallel to the yz plane passing through opening N2. When secondary molded resin R2 is injection-molded into molded coil 20 and core 10, molded coil 21 has opening N2 having dimension W2 in the height direction (z-axis direction), and therefore secondary molded resin R2 is filled into the gap between core 10 and coil C1 through opening N2. Hereinafter, the gap between the core 10 and the coil C1 will be referred to as the inner circumferential side of the core 10, and the opposite side will be referred to as the outer circumferential side of the core 10.

[0032] 5 is a cross-sectional view showing the internal state of mold 15 used in the method for manufacturing reactor 41 according to embodiment 1, i.e., the manufactured reactor 41. In FIG. 2, the z-axis direction is the height direction. Secondary molding resin R2 is injected, for example, in the negative z-axis direction. Core 10 and molded coil 21 are inserted into mold 15. Then, secondary molding resin R2 is injected into core 10 and molded coil 21 to perform injection molding. During the injection molding process of secondary molding resin R2, holes h2, which are insertion holes for bolts or the like, are also formed in the mounting flange portion.

[0033] 5, the resin flow path of secondary molding resin R2 during the injection molding process will be described. The resin flow path of secondary molding resin R2 includes inner flow paths 31a and 31b that pass through the inner periphery of core 10, outer flow path 32 that passes through the outer periphery of core 10, and flow path 33 that passes between the pair of cores 10. Inner flow paths 31a and 31b, outer flow path 32, and flow path 33 are continuous, without interruption. Because molded coil 21 has openings N1 and N2, secondary molding resin R2 fills inner flow paths 31a and 31b preferentially over outer flow path 32.

[0034] <Method of manufacturing reactor according to comparative example> Next, a method for manufacturing a reactor according to a comparative example will be described with reference to the drawings. The method for manufacturing the reactor according to the comparative example is similar to the method for manufacturing the reactor according to embodiment 1, in that the pair of cores 10 are butted together while fitting the molded coil 20 into the recess 14 of the core 10, and the cores 10 and the molded coil 21 are assembled together. Then, secondary molded resin R2 is injection molded onto the core 10 and the molded coil 20, thereby manufacturing the reactor. The following description will focus on the differences from the method for manufacturing the reactor according to the first embodiment, namely, the molded coil 20.

[0035] Fig. 6 is a diagram showing molded coil 20 used in a method for manufacturing a reactor according to a comparative example. Molded coil 20 in Fig. 6 and molded coil 21 in Fig. 1 differ in the portions that are covered with primary molding resin R1. Here, with reference to Fig. 6, the portions of molded coil 20 that are not covered with primary molding resin R1, i.e., the exposed portions of coil C1, will be described.

[0036] Molded coil 20 is composed of coil C1 and primary molded resin R1 that covers coil C1. The upper and lower sides of the outer surface of molded coil 20 that faces recesses 14 of the pair of cores are covered with primary molded resin R1, and coil C1 is exposed at the center in the up-down direction (z-axis direction). In other words, an opening N3 is provided at the center of the outer surface that faces recesses 14 of the pair of cores.

[0037] On the other hand, the end faces of molded coil 20 facing recesses 14 of the pair of cores are covered with primary molding resin R1 except for holes h1 on the end faces. In the example shown in Fig. 1, three holes h1 are formed aligned in the vertical direction (z-axis direction), but it is not necessary to have a central hole h1 in the vertical direction.

[0038] In molded coil 20 shown in FIG. 6, the area of hole h1 that is not covered with primary molding resin R1 is less than half on the end faces of the pair of cores that face recesses 14.

[0039] On the other hand, opening N3 in molded coil 20 shown in Fig. 6 is smaller than opening N2 in molded coil 21 shown in Fig. 1. In other words, in molded coil 21 shown in Fig. 1, the entire outer surface facing recesses 14 of the pair of cores is not covered with primary molded resin R1. In contrast, in molded coil 20 shown in Fig. 6, a portion of the outer surface facing recesses 14 of the pair of cores is covered with primary molded resin R1.

[0040] 7 is a vertical cross-sectional view of reactor 40 according to a comparative example taken along a line passing through hole h1. Reactor 40 is composed of core 10, molded coil 20, and secondary molded resin R2. Molded coil 20 and core 10 are covered with secondary molded resin R2. When secondary molded resin R2 is injection-molded onto molded coil 20 and core 10, molded coil 20 has hole h1 with dimension W3 in the height direction (z-axis direction), and therefore secondary molded resin R2 fills the gap between core 10 and coil C1 through hole h1.

[0041] 8 is a vertical cross-sectional view passing through opening N3 of reactor 40 according to the comparative example. When secondary molded resin R2 is injection-molded into molded coil 20 and core 10, molded coil 20 has opening N3 having dimension W4 in the height direction (z-axis direction), and therefore secondary molded resin R2 fills the gap between core 10 and coil C1 through opening N3.

[0042] FIG. 9 is a cross-sectional view showing the internal state of a mold 25 used in a manufacturing method for reactor 40 according to a comparative example, i.e., a manufactured reactor 40. Core 10 and molded coil 20 are inserted into mold 25. Then, secondary molded resin R2 is injected into core 10 and molded coil 20 to perform injection molding. At this time, the outer surface and end surface of molded coil 20 facing recesses 14 of the pair of cores are mostly covered with primary resin mold R1. The covered portions of primary resin mold R1 prevent secondary molded resin R2 from filling inner flow paths 31a and 31b. Therefore, in mold 25, secondary molded resin R2 fills outer flow path 32 preferentially over inner flow paths 31a and 31b. Therefore, core 10 in FIG. 9 is pressurized from the outside to the inside by the resin pressure of secondary molded resin R2, as indicated by the arrows, which can cause core 10 to crack.

[0043] Here, with reference to Fig. 2, a description will be given of the damaged portion of core 10. In core 10, the width of outer legs 13a and 13b in the y-axis direction is narrower than the width of center leg 12 in the y-axis direction. Furthermore, the width of connecting portions 11a and 11b in the x-axis direction is narrower than the width of center leg 12 in the x-axis direction. When manufacturing a smaller-sized reactor, outer legs 13a, 13b and connecting portions 11a, 11b become thinner, and there is a possibility that outer legs 13a, 13b and connecting portions 11a, 11b may break during molding.

[0044] To prevent cracking of core 10, the inventors changed the dimensions of inner flow paths 31a and 31b, outer flow path 32, and flow path 33 to study cracking modes of core 10. FIG. 10 is a schematic diagram showing three cracking modes of core 10 used in a manufacturing method for reactor 40 according to a comparative example. Mode 1 occurs when secondary molding resin R2 is filled first in outer flow path 32. In mode 1, outer legs 13a and 13b are pressurized in the y-axis direction by secondary molding resin R2 as shown by the arrows, generating high stress at location X1. A possible cause of mode 1 is the lack of a support mechanism inside outer legs 13a and 13b.

[0045] Mode 2 also occurs when secondary molding resin R2 is filled first through outer flow path 32. In Mode 2, connections 11a and 11b are pressurized in the x-axis direction as shown by the arrows, generating high stress at location X2. The cause of Mode 2 is thought to be the lack of a support mechanism inside connections 11a and 11b.

[0046] Mode 3 occurs when the secondary molding resin R2 is filled from the top side of core 10 first. In Mode 3, core 10 is pressed downward as shown by the arrow, causing high stress in area X3. A possible cause of Mode 3 is the lack of a support mechanism below core 10 (e.g., on the negative z-axis side).

[0047] From the above considerations, it is believed that cracking of core 10 can be prevented by filling secondary molding resin R2 preferentially into inner flow paths 31a and 31b rather than outer flow path 32.

[0048] <Effects of the manufacturing method of the reactor according to the first embodiment> Next, the effects of the method for manufacturing the reactor according to the first embodiment will be described. Comparing the dimension W1 of opening N1 in molded coil 21 in Fig. 3 with the dimension W3 of hole h1 in molded coil 20 in Fig. 8, the dimension W1 of opening N1 is larger than the dimension W3 of hole h1. Therefore, in the method for manufacturing the reactor according to embodiment 1, secondary molding resin R2 is filled preferentially on the inner circumferential side of core 10 rather than on the outer circumferential side of core 10.

[0049] 4 and the dimension W4 of the opening N3 in the molded coil 20 in Fig. 8, the dimension W2 of the opening N2 in the molded coil 21 is larger than the dimension W4 of the opening N3 in the molded coil 20. Therefore, in the method for manufacturing the reactor according to the first embodiment, the secondary molding resin R2 is filled preferentially on the inner circumferential side of the core 10 rather than on the outer circumferential side of the core 10.

[0050] Comparing the molded coil 21 shown in FIG. 5 with the molded coil 20 shown in FIG. 9, the molded coil 21 shown in FIG. 5 has an opening N1 and an opening N2. Therefore, when the molded coil 21 shown in FIG. 5 is used, the filling of the secondary molded resin R2 into the inner flow passages 31a and 31b is less likely to be hindered than when the molded coil 20 shown in FIG. 9 is used. In other words, when the molded coil 21 shown in FIG. 5 is used, the secondary molded resin R2 fills the inner flow passages 31a and 31b preferentially rather than the outer flow passage 32. Therefore, the resin pressure of the secondary molded resin R2 during injection molding can be applied from the inside to the outside, as shown by the arrows in FIG. 5, which can suppress cracking of the core 10.

[0051] As described above, in the method for manufacturing the reactor according to the first embodiment, in molded coil 21, the entire outer surface facing recesses 14 of paired cores 10, or more than half of the end surface facing recesses 14 of paired cores 10, is not covered with primary molding resin R1, and coil C1 is exposed. Therefore, when secondary molding resin R2 is injected into core 10 and molded coil 21, the resin fills preferentially toward the inner periphery of the core rather than the outer periphery, making it possible to support the resin pressure during molding of secondary molding resin R2 from the inside and suppressing cracking of core 10.

[0052] (Embodiment 2) Next, a method for manufacturing the reactor according to the second embodiment will be described with reference to FIG. The method for manufacturing a reactor according to the second embodiment is different from the method for manufacturing a reactor according to the first embodiment in that a mold used for manufacturing the reactor is different. Fig. 11 is a diagram showing the inside and outside of a mold 35 used in the method for manufacturing a reactor according to the second embodiment. The internal structure of the mold 35 is similar to that of the mold 25 according to the first embodiment, and therefore a description thereof will be omitted. Here, core support pins 16a, 16b, 16c, 16d, 16e, 16f, and 16g will be described.

[0053] The mold 35 includes core support pins 16a, 16b, 16c, 16d, 16e, 16f, and 16g. The mold 35 may further include a hydraulic device (not shown) that controls the positions and pressures of the core support pins 16a, 16b, 16c, 16d, 16e, 16f, and 16g.

[0054] Core support pins 16a, 16b, 16c, 16d, 16e, 16f, and 16g are provided on the outer periphery of core 10 so as to support the pair of cores 10 from the outside. Core support pins 16a, 16b, 16c, 16d, 16e, 16f, and 16g may have a predetermined thickness (y-axis direction), depth (x-axis direction), and height (z-axis direction) that are sufficient to support the pair of cores 10 from the outside.

[0055] The core support pins 16f, 16g are provided at positions facing the opening N1 in the molded coil 21 via the connecting portions 11a and 11b. In the example shown in Fig. 11, the core support pins 16f, 16g have flanges with holes h2 that are insertion holes for mounting bolts or the like, and therefore support only the core 10 on one side.

[0056] Furthermore, core support pins 16a, 16b, 16c, and 16d are provided at positions facing opening N2 in molded coil 21 via outer legs 13a and 13b. That is, core support pins 16a, 16b, 16c, 16d, 16f, and 16g are provided at positions facing openings N1 and N2 in molded coil 21 via core 10.

[0057] Note that some of the core support pins 16e do not have to be positioned opposite the openings N1 and N2. In the example shown in Fig. 11, the core support pin 16e is provided between flanges having a hole h2. It is preferable that the positions of the core support pins 16a, 16b, 16c, 16d, 16e, 16f, and 16g in the height direction (z-axis direction) are the same so that the core 10 is supported evenly from the outside.

[0058] When the secondary molding resin R2 is injected onto the core 10 and the molded coil 21, the secondary molding resin R2 is not filled in the areas where the core 10 is in contact with the core support pins 16a, 16b, 16c, 16d, 16e, 16f, and 16g, and therefore openings corresponding to the shapes of the core support pins 16a, 16b, 16c, 16d, 16e, 16f, and 16g are formed in the manufactured reactor.

[0059] If secondary molding resin R2 is injected into core 10 and molded coil 21 at a high injection speed, core 10 is pressurized by the resin pressure of secondary molding resin R2 acting outward, as indicated by the arrows in the x- and y-axes in Fig. 11. As a result, outer legs 13a and 13b or connecting portions 11a and 11b may break due to the resin pressure of secondary molding resin R2, which has preferentially filled toward the inner periphery of the core.

[0060] Core support pins 16a, 16b, 16c, and 16d support outer legs 13a and 13b from the outside, suppressing the resin pressure indicated by the arrows in the y-axis direction that acts when secondary molding resin R2 is injection molded. Core support pins 16e, 16f, and 16g support connecting portions 11a and 11b from the outside, suppressing the resin pressure indicated by the arrows in the x-axis direction that acts when secondary molding resin R2 is injection molded. That is, core support pins 16a, 16b, 16c, 16d, 16e, 16f, and 16g contact and support core 10 from the outside, suppressing the resin pressure that acts from the inside to the outside of core 10 when secondary molding resin R2 is preferentially filled into inner flow paths 31a and 31b.

[0061] In addition, mold 35 may be equipped with a hydraulic device (not shown) that controls the pressure of core support pins 16a, 16b, 16c, 16d, 16e, 16f, and 16g, so the pressure that suppresses the resin pressure of secondary molding resin R2 using core support pins 16a, 16b, 16c, 16d, 16e, 16f, and 16g can be controlled in accordance with the resin pressure acting from the inside to the outside of core 10, which changes in accordance with the injection speed of secondary molding resin R2.

[0062] As described above, the method for manufacturing the reactor according to the second embodiment has core support pins 16a, 16b, 16c, 16d, 16e, 16f, and 16g that support core 10 from the outside. Therefore, secondary molding resin R2 filled on the inner circumferential side of the core can suppress the resin pressure acting from the inside to the outside of core 10, and can prevent core 10 from cracking.

[0063] The present disclosure is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the present disclosure. [Explanation of symbols]

[0064] 10 cores 11 Base 11a, 11b connection part 12 Middle leg 13a, 13b outer legs 14 Recess 15, 25, 35 molds 16a, 16b, 16c, 16d, 16e, 16f, 16g Core support pin 20, 21 Molded coil 31a, 31b Inner flow passage 32 Outer channel 33 Flow path 40, 41 Reactor C1 coil h1, h2 holes N1, N2, N3 opening R1 Primary molding resin R2 Secondary molding resin X1, X2, X3 parts

Claims

1. A step of preparing a pair of cores having U-shaped recesses and a molded coil in which a cylindrical coil is covered with a primary molding resin; a step of butting the pair of cores together while fitting the molded coil into the recess, and assembling the pair of cores and the molded coil; and injecting a secondary molding resin into the assembled pair of cores and the molded coil, In the injecting step, the secondary molding resin is filled into inner circumferential sides of the cores, which are gaps between the recesses of the pair of cores and the coil, and into outer circumferential sides of the cores, In the prepared molded coil, the entire outer surfaces of the pair of cores facing the recesses are not covered with the primary molding resin, and the coils are exposed; In the prepared molded coil, more than half of the end surfaces of the pair of cores facing the recesses are not covered with the primary molding resin, and the coils are exposed; In the injecting step, the secondary molding resin is preferentially filled into the inner peripheral side of the core rather than the outer peripheral side of the core through the exposed portion of the coil. Reactor manufacturing method.

2. In the injecting step, the core is supported from the outside. A method for manufacturing the reactor according to claim 1.

3. A step of preparing a pair of cores having U-shaped recesses and a molded coil in which a cylindrical coil is covered with a primary molding resin; a step of butting the pair of cores together while fitting the molded coil into the recess, and assembling the pair of cores and the molded coil; and injecting a secondary molding resin into the assembled pair of cores and the molded coil, In the injecting step, the secondary molding resin is filled into inner circumferential sides of the cores, which are gaps between the recesses of the pair of cores and the coil, and into outer circumferential sides of the cores, In the prepared molded coil, more than half of the end surfaces of the pair of cores facing the recesses are not covered with the primary molding resin, and the coils are exposed; In the injecting step, the secondary molding resin is preferentially filled into the inner peripheral side of the core rather than the outer peripheral side of the core through the exposed portion of the coil. Reactor manufacturing method.

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