Reactor and reactor manufacturing method

Abstract

To provide a reactor and a reactor manufacturing method that prevent poor connection at the joint of a core member even when the reactor is pressed.SOLUTION: A reactor 10 includes a coil, a core having outer legs on which the coil is not attached, and a molded resin covering a part of the coil and a part of the core except for a bottom surface 12. The core includes a joint where multiple split core members are joined to at least the outer legs on which the coil is not wound. The molded resin includes an upper surface covering portion 71 that covers the upper surface of the joint, a side surface covering portion 72 that covers the side surface of the joint, and a lower surface covering portion 73 that covers the lower surface of the joint. The lower surface covering portion 73 extends in the extension direction of the outer legs and supports the joint.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a reactor and a method for manufacturing the reactor.

Background Art

[0002] Reactors are used in various applications such as OA equipment, solar power generation systems, and automobiles. A reactor is formed by mounting a coil on a core made of a magnetic material. Further, the reactor fixes the core and the coil with a mold resin. The mold resin is interposed between the core and the coil and insulates the core and the coil.

[0003] The coil has a lead wire that is electrically connected to an external device. The lead wire is connected by welding or the like to a bus bar. The bus bar is also connected to a terminal of an external device. In this way, the reactor is electrically connected to the external device via the bus bar.

[0004] When the coil is supplied with power from an external device, it generates a magnetic flux. This magnetic flux passes through the annular core as a magnetic path. In this way, the reactor is an electromagnetic component that converts electrical energy into magnetic energy and stores and releases it.

[0005] The coil becomes a heat generation source of the reactor, and the reactor temperature rises. Therefore, it is necessary to release the heat generated in the reactor to the outside. As a heat dissipation method, it is known to place the reactor on a heat dissipation member and release the heat to the heat dissipation member.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In order to enhance the heat dissipation performance of the reactor, it is necessary to bring the reactor into close contact with a heat dissipation member. Therefore, when installing the reactor on the heat dissipation member, the reactor is strongly pressed from above. On the other hand, the core is formed in an annular shape by joining a plurality of divided core members. Therefore, when the reactor is pressed, there is a risk that the joint portion of the joined core members will be damaged and the core members will be poorly joined.

[0008] The present invention has been made to solve the above problems, and an object thereof is to provide a reactor that prevents the joint portion of the core members from becoming poorly connected even when the reactor is pressed.

Means for Solving the Problems

[0009] The reactor of the present invention includes a coil, a core having legs on which the coil is not mounted, and a molded resin that covers a part of the coil excluding the lower surface and a part of the core. The core has a joint portion where a plurality of divided core members are joined at least on the legs on which the coil is not wound. The molded resin has an upper surface covering portion that covers the upper surface of the joint portion, a side surface covering portion that covers the side surface of the joint portion, and a lower surface covering portion that covers the lower surface of the joint portion. The lower surface covering portion extends in the extending direction of the legs and supports the joint portion.

[0010] The method for manufacturing a reactor according to the present invention is a method for manufacturing a reactor in which a coil and a core having legs on which the coil is not mounted are coated with a molding resin, and includes a molding step of molding a part of the coil and a part of the core with the molding resin. The reactor includes a core coating resin that coats the periphery of the core. The core has a joint portion where a plurality of divided core members are joined to at least the legs around which the coil is not wound. The molding resin has an upper surface coating portion that coats the upper surface of the joint portion, a side surface coating portion that coats the side surface of the joint portion, and a lower surface coating portion that coats the lower surface of the joint portion. The lower surface coating portion extends in the extending direction of the legs, supports the joint portion, and the core coating resin has a leg coating portion that coats the legs. The leg coating portion has a groove portion in which the surface of the leg coating portion is recessed. The groove portion is provided on the upper surface of the leg coating portion and extends toward the side surface of the joint portion. In the molding step, the molding resin is guided by the groove portion and flows into the joint portion.

Advantages of the Invention

[0011] According to the present invention, it is possible to obtain a reactor that prevents the joint portion of the core members from becoming poorly connected even when the reactor is pressed.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0013] (Embodiment) The reactor according to the embodiment will be described with reference to the drawings. FIG. 1 is a perspective view showing the overall configuration of the reactor 10. FIG. 2 is an exploded perspective view showing the overall configuration of the reactor 10. In each drawing, for ease of understanding, the thickness, dimensions, positional relationship, ratio, shape, etc. may be emphasized, and the present invention is not limited to such emphasis.

[0014] As shown in FIGS. 1 and 2, the reactor 10 includes a coil 1, a core 5, a core coating resin 6, and a mold resin 7. The coil 1 is attached to the core 5. The core 5 is coated with the core coating resin 6. That is, the core coating resin 6 is interposed between the coil 1 and the core 5. The core coating resin 6 insulates the coil 1 and the core 5.

[0015] The mold resin 7 coats a part of the coil 1 and the core 5 and fixes the coil 1 and the core 5. When power is supplied from an external device to the coil 1, the coil 1 generates a magnetic flux, and the core 5 forms a closed magnetic path through which the magnetic flux passes. In this way, the reactor 10 is an electromagnetic component that converts electrical energy into magnetic energy and stores and releases it.

[0016] The coil 1 is composed of a single conductive member insulated with enamel or the like. The coil 1 is formed by winding the conductive member in a cylindrical shape while shifting the winding position in the winding axis direction. The conductive member is, for example, a rectangular wire, and the coil 1 is an edgewise coil in which the wide surface of the conductive member extends in a direction orthogonal to the winding axis of the coil 1. Note that the coil 1 may be a flatwise coil. Also, as the conductive member, a round wire may be used.

[0017] FIG. 3 is an exploded perspective view showing the state before the various covers 2, 3, and 4 are attached to the coil 1. As shown in FIG. 3, the coil 1 has a rounded shape with curved surfaces 14 provided between four flat surfaces of an upper surface 11, a lower surface 12, and a pair of side surfaces 13, respectively. The lower surface 12 is located on the opposite side of the upper surface 11, and a pair of side surfaces 13 are arranged between the upper surface 11 and the lower surface 12. Note that the vertical direction is the vertical direction of the coil 1 when it is arranged in the mold during the mold molding described later, and does not refer to the positional relationship when the reactor 10 is installed on the heat dissipation member 8 (see FIG. 9) described later. Also, the flat surface is a surface that is relatively flat compared to the curved surface 14, and a state where a large arc is drawn with a gentle curvature due to the swelling of the conductive member during winding is also included in the flat surface.

[0018] The coil 1 has two lead wires 15. The lead wires 15 are connected to a bus bar (not shown) by welding or the like. The bus bar is electrically connected to an external device. The reactor 10 is electrically connected to the external device via the bus bar.

[0019] As shown in FIG. 2, the periphery of the coil 1 is covered by an upper cover 2, a lower cover 3, and an end face cover 4. The upper cover 2, the lower cover 3, and the end face cover 4 prevent the mold, the pressing member, the jig, the resin to be injected, etc. from directly contacting the coil 1 during the mold molding. As shown in FIG. 3, the upper cover 2, the lower cover 3, and the end face cover 4 are each formed as a separate body.

[0020] The upper cover 2, the lower cover 3, and the end face cover 4 are made of resin. Examples of the type of resin include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), PBT (Polybutylene Terephthalate), and the like.

[0021] The upper cover 2 covers the upper surface 11 of the coil 1. The upper cover 2 covers the entire upper surface 11 of the coil 1 and also covers a part of each curved surface 14 connected to the upper surface 11. The upper cover 2 abuts against the upper mold during molding.

[0022] The lower cover 3 is disposed on the lower surface 12 of the coil 1. The lower cover 3 has a frame portion 31 and a wall portion 32. The frame portion 31 and the wall portion 32 are connected seamlessly and integrally formed.

[0023] The frame portion 31 is annular. The frame portion 31 is disposed on the lower surface 12 of the coil 1. Therefore, the lower surface 12 of the coil 1 is not covered by the lower cover 3 and is exposed. The frame portion 31 may expose not only the lower surface 12 of the coil 1 but also a part of the curved surface 14 connected to the lower surface 12. The frame portion 31 abuts against the mold during molding. The frame portion 31 prevents the resin from flowing into the lower surface 12 of the coil 1 during molding.

[0024] The wall portion 32 rises from the side of the frame portion 31 parallel to the winding axis. More specifically, the wall portion 32 rises from the inner edge of the frame portion 31. The wall portion 32 faces the curved surface 14 connected to the lower surface 12 of the coil 1 and the side surface 13 of the coil 1. The tip of the wall portion 32 abuts against the side surface 13 of the coil 1.

[0025] The end face cover 4 covers one end face orthogonal to the winding axis of the coil 1. The end face cover 4 is annular. During molding, the coil 1 is pressed so that the length in the winding axis direction becomes a desired length. At this time, of the pair of end faces orthogonal to the winding axis of the coil 1, one is pressed and the other is fixed. The end face cover 4 covers the end face on the pressed side. The end face cover 4 is provided so as to be movable in the winding axis direction. That is, the end face cover 4 moves in response to the compression of the coil 1.

[0026] The core 5 includes a magnetic material. As the core 5, a compressed powder core, a ferrite core, a laminated steel sheet, a metal composite core, or the like can be used. The metal composite core is a magnetic material obtained by kneading magnetic powder and resin and curing the resin.

[0027] As shown in FIG. 2, the core 5 is composed of two E-shaped core members 51 and 52. By joining the E-shaped core members 51 and 52, the core 5 becomes an annular shape. Note that the E-shaped core members 51 and 52 correspond to the divided core members in the claims.

[0028] The E-shaped core members 51 and 52 include a middle leg 53, a pair of outer legs 54, and a yoke portion 55. The middle leg 53 has the coil 1 mounted thereon. The pair of outer legs 54 extend parallel to the extending direction of the middle leg 53 and are respectively disposed with a gap therebetween on both sides adjacent to the middle leg 53. The extending lengths of the middle leg 53 and the pair of outer legs 54 are the same. The coil 1 is not mounted on the outer legs 54. The yoke portion 55 connects the middle leg 53 and the pair of outer legs 54.

[0029] The opposite end faces of the middle leg 53 and the pair of outer legs 54 that connect to the yoke portion 55 serve as connection surfaces. By connecting the connection surfaces of the middle leg 53 and the pair of outer legs 54, the core 5 becomes an annular shape. Therefore, when the annular core 5 is formed, a joint portion 56 that becomes the boundary between the E-shaped core members 51 and 52 is generated (see FIG. 5). The E-shaped core members 51 and 52 may be joined using an adhesive. In the outer leg 54, the side surface facing the middle leg 53 may be referred to as the inner side surface, and the side surface opposite to the inner side surface may be referred to as the outer side surface.

[0030] A core coating resin 6 is formed around the core 5. The core coating resin 6 coats the peripheries of the E-shaped core members 51 and 52 by performing mold molding on each of the E-shaped core members 51 and 52.

[0031] The core coating resin 6 is made of resin. Examples of the type of resin include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), PBT (Polybutylene Terephthalate), and the like.

[0032] The core coating resin 6 has a middle leg coating portion 61, an outer leg coating portion 62, and a yoke coating portion 63. The middle leg coating portion 61 coats the middle leg 53. The outer leg coating portion 62 coats the outer leg 54 except for the connection surface. The yoke coating portion 63 coats the yoke portion 55. Note that the outer leg coating portion 62 corresponds to the leg coating portion in the claims.

[0033] Figure 4 is an enlarged perspective view of the outer leg coating portion 62. The core coating resin 6 has a groove portion 64. The groove portion 64 is provided in the outer leg coating portion 62 that coats the E-shaped core member 52. The groove portion 64 is provided on the upper surface of the outer leg coating portion 62. The groove portion 64 has a base end near the injection mark M formed in the mold resin 7 described later, extends to near the side surface of the outer leg coating portion 62, and communicates with the notch 65. That is, the groove portion 64 connects the injection mark M and the notch 65. Note that the injection mark M indicates the position where the resin of the mold resin 7 was injected during mold molding. That is, the injection mark M indicates the gate position where the resin was injected during mold molding.

[0034] The groove width of the groove portion 64 gradually widens from near the injection mark M and becomes maximum at the location where it is connected to the notch 65. That is, the groove width of the groove portion 64 widens toward the notch 65. The groove portion 64 has a wall 641. The wall 641 rises from the bottom surface of the groove portion 64. However, the wall 641 is lower than the side wall forming the groove portion 64. The wall 641 extends from the base end position of the groove portion 64 near the injection mark M to the notch 65.

[0035] The notch 65 is formed on the side surface of the outer leg covering portion 62 that covers the outer side surface of the outer leg 54. That is, the notch 65 is formed on the outer side surface that is opposite to the inner side surface of the outer leg covering portion 62 facing the middle leg covering portion 61. The surface of the outer leg covering portion 62 is notched at the notch 65. That is, the outer leg covering portion 62 where the notch 65 is formed has a thinner covering thickness than the other outer leg covering portions 62 that cover the outer side surface of the outer leg 54.

[0036] The notch 65 is formed from the tip of the outer leg covering portion 62 toward the yoke covering portion 63. The length of the notch 65 in the winding axis direction is at least the length that communicates with the groove portion 64. Also, the notch 65 extends from the upper end to the lower end of the side surface of the outer leg covering portion 62. The notch 65 communicates with the groove portion 64.

[0037] FIG. 5 is a diagram showing a state in which the E-shaped core members 51 and 52 are joined. As shown in FIG. 5, the notch 65 is formed on the side surface of each outer leg covering portion 62 that covers the E-shaped core members 51 and 52. When the E-shaped core members 51 and 52 are connected, the notches 65 communicate with each other, and a large groove 651 is formed. Each outer leg covering portion 62 has a curved portion 621. The curved portion 621 is formed at the tip corner of the outer leg covering portion 62. The curved portion 621 is formed at the corner connecting the connection surface where the outer legs 54 of the E-shaped core members 51 and 52 are connected and the outer side surface of the outer leg 54. When the E-shaped core members 51 and 52 are connected, one depression is formed by the two curved portions 621. The mold resin 7 is formed in the notch 65 including this depressed portion.

[0038] The core covering resin 6 has a protrusion 66. The protrusion 66 is provided on the upper surface of the outer leg covering portion 62. The protrusion 66 is provided at the tip of the outer leg covering portion 62. In other words, the protrusion 66 is provided near the joint of the outer leg 54. The protrusion 66 is formed on the outer leg covering portion 62 that covers each outer leg 54 of the E-shaped core members 51 and 52.

[0039] As shown in FIG. 4, the protruding portion 66 has a cylindrical shape and has a hollow portion 661. The hollow portion 661 is a space, and the mold resin 7 is formed inside this hollow portion 661. The hollow portion 661 extends in the winding axis direction. The hollow portion 661 is circular, but may have other shapes such as rectangular. More specifically, the protruding portions 66 provided on each of the E-shaped core members 51 and 52 are arranged such that the hollow portions 661 are coaxial. That is, the protruding portions 66 provided on the E-shaped core members 51 and 52 are arranged opposite to each other (see FIG. 5).

[0040] FIG. 6 is a perspective view of the core 5 covered with the core coating resin 6 as seen from below. As shown in FIG. 6, the core coating resin 6 has a recess 67. The recess 67 is disposed on the lower surface of the outer leg covering portion 62. The depth of the recess 67 reaches the outer leg 54, and the outer leg 54 is exposed from the recess 67. Since the mold resin 7 is formed in the recess 67, the outer leg 54 is not exposed in the state after molding. A plurality of recesses 67 are provided. The recesses 67 are arranged along the extending direction of the outer leg 54 at substantially equal intervals.

[0041] As shown in FIG. 1, the mold resin 7 covers the joint portion of the outer legs 54 of the E-shaped core members 51 and 52. The mold resin 7 has an upper surface covering portion 71, a side surface covering portion 72, and a lower surface covering portion 73. The upper surface covering portion 71, the side surface covering portion 72, and the lower surface covering portion 73 are integrally molded products that are continuously connected without seams.

[0042] The upper surface covering portion 71 covers the joint portion 56 on the upper surface of the outer leg 54. That is, the upper surface covering portion 71 covers the upper surfaces of the outer leg covering portions 62 of the E-shaped core members 51 and 52. The upper surface covering portion 71 covers the groove portion 64. The upper surface covering portion 71 is formed inside the groove portion 64 and covers the wall 641 provided in the groove portion 64.

[0043] Further, the upper surface covering portion 71 has a connecting portion 711 that covers the protruding portion 66. The connecting portion 711 covers the periphery of the protruding portion 66 and is also formed inside the hollow portion 661. That is, the connecting portion 711 formed inside the hollow portion 661 is columnar. The connecting portion 711 covers the protruding portions 66 provided on the E-shaped core members 51 and 52 respectively. That is, two protruding portions 66 are covered by one connecting portion 711. Therefore, the connecting portion 711 is formed on the joint portion 56.

[0044] An injection mark M is formed on the upper surface covering portion 71. The injection mark M indicates the position where the resin constituting the mold resin 7 is injected during mold molding. The injection mark M is located on the upper surface of the yoke portion 55. That is, the upper surface covering portion 71 covers not only the upper surface of the outer leg covering portion 62 but also a part of the upper surface of the yoke covering portion 63. The injection mark M is located on the upper surface covering portion 71 within the extension region in the winding axis direction of the end face of the coil 1 orthogonal to the winding axis. By forming the injection mark M at this position, the coil 1 (via the end face cover 4) can be pressed using the injection pressure of the resin during mold molding to compress the coil 1. Note that, to compress the coil 1 using the injection pressure of the resin, it is sufficient if a part of the injection position is within the extension region in the winding axis direction of the end face of the coil 1 orthogonal to the winding axis. Therefore, it is sufficient if a part of the injection mark M is also included within the extension region in the winding axis direction of the end face of the coil 1 orthogonal to the winding axis.

[0045] The side surface covering portion 72 covers the joint portion 56 on the outer side surface of the outer leg 54. The side surface covering portion 72 covers across the outer side surfaces of the outer leg covering portions 62 of the E-shaped core members 51 and 52. The side surface covering portion 72 is formed inside the notch 65. That is, the side surface of the side surface covering portion 72 and the outer leg covering portion 62 are flush. The side surface covering portion 72 extends from the upper end to the lower end of the outer side surface of the outer leg covering portion 62.

[0046] FIG. 7 is a perspective view of the reactor 10 as viewed from the bottom surface side. The bottom covering portion 73 covers the joint portion 56 on the bottom surface of the outer leg covering portion 62. The bottom covering portion 73 extends in the extending direction of the outer leg 54. The bottom covering portion 73 extends from the joint portion 56 to the boundary portion between the outer legs 54 of the E-shaped core members 51 and 52 and the yoke portion 55. That is, the length of the bottom covering portion 73 in the winding axis direction is the sum of the lengths of the respective outer legs 54 of the E-shaped core members 51 and 52. The width of the bottom covering portion 73 is at least half of the distance between the inner surface and the outer surface of the outer leg 54.

[0047] The bottom covering portion 73 abuts against the frame-shaped portion 31. Therefore, the bottom covering portion 73 does not cover the bottom surface 12 of the coil 1. Also, the molded resin 7 does not cover the bottom surface 12 of the coil 1. Therefore, the bottom surface 12 of the coil 1 is exposed. The molded resin 7 covers only a part (near the injection mark M) of the upper surface of the yoke covering portion 63, and does not cover the surfaces of the other yoke covering portions 63.

[0048] FIG. 8 is an enlarged perspective view of the bottom covering portion 73. As shown in FIG. 8, the bottom covering portion 73 has convex portions 731. The convex portions 731 are formed on the upper surface of the bottom covering portion 73. The upper surface of the bottom covering portion 73 is the surface that abuts against the outer leg covering portion 62. The convex portions 731 are formed inside the concave portions 67 of the core covering resin 6. The protruding length of the convex portions 731 is the same as the depth of the concave portions 67. The tips of the convex portions 731 are in contact with the outer legs 54. The number of the convex portions 731 is the same as the number of the concave portions 67.

[0049] Note that the molded resin 7 covers the joint portion 56 on the inner surface of the outer leg covering portion 62. Also, the molded resin 7 covers a part of the coil 1 except for the middle leg covering portion 61 and the bottom surface 12. On the other hand, the molded resin 7 does not cover the back surface (the surface opposite to the side connected to the outer leg covering portion 62) and the bottom surface of the yoke covering portion 63. Also, the molded resin 7 does not cover the yoke side outer surface of the outer leg covering portion 62, at least the central portion in the extending direction of the outer leg covering portion 62.

[0050] (Operation) Next, the flow of the resin during mold forming will be described. First, the coil 1 with the upper cover 2, the lower cover 3, and the end face cover 4 attached is assembled to the E-shaped core members 51 and 52 to produce an assembly. This assembly is housed in a mold. In this state, mold forming is performed.

[0051] The gate through which the resin is injected during mold forming is located in the upper covering portion 71 within the extension region in the winding axis direction of the end face of the coil 1 orthogonal to the winding axis. Therefore, the injection pressure of the resin acts on the compression of the coil 1. Note that after mold forming, an injection mark M is formed at this gate position.

[0052] The groove portion 64 extends from the gate position to the notch 65. Therefore, the resin injected from the gate is guided to the notch 65 using the groove portion 64 as a flow path. Thus, the resin can be spread to every corner of the mold for forming the side covering portion 72.

[0053] The notch 65 communicates with the groove portion 64 and extends from the upper end to the lower end of the outer side surface of the outer leg covering portion 62. Also, by joining the E-shaped core members 51 and 52, each notch 65 becomes a large groove 651. Therefore, the resin that reaches the notch 65 is guided from the upper end to the lower end of the outer side surface of the outer leg covering portion 62.

[0054] Then, the resin guided to the lower end of the notch 65 spreads to the lower surface of the outer leg covering portion 62. In this way, since the flow path is formed by the groove portion 64 and the notch 65, the resin injected from the gate easily heads towards the lower surface of the outer leg covering portion 62. Therefore, the resin spreads to every corner of the lower covering portion 73 and the convex portion 731. Thus, the lower covering portion 73 can be extended in the extending direction of the outer leg 54.

[0055] Finally, by solidifying the resin, the upper covering portion 71, the side covering portion 72, and the lower covering portion 73 of the molded resin 7 are formed. The reactor 10 is formed in this manner.

[0056] FIG. 9 is a view showing a state where the reactor 10 is installed on the heat radiating member 8. The reactor 10 of the present embodiment is installed on the heat radiating member 8. The heat radiating member 8 abuts on the lower surface 12 of the coil 1. The heat radiating member 8 releases the heat of the reactor 10 to the outside. As the heat radiating member 8, for example, an elastic member such as a heat radiating sheet, a heat radiating grease, a heat radiating gap filler (a material that becomes sheet-like and has elasticity when cured from a paste state during application) is used.

[0057] In order to transfer more heat of the reactor 10 to the heat radiating member 8, it is necessary to bring the reactor 10 into close contact with the heat radiating member 8. In particular, when the heat radiating member 8 is an elastic member as in the present embodiment, in order to enhance the adhesion, as shown in FIG. 9, the reactor 10 is strongly pressed against the heat radiating member 8 and fixed. At this time, not only the upper surface 11 portion of the coil 1 but also the outer leg 54 portion is pressed. Even when the heat radiating member 8 is in close contact only with the lower surface 12 of the coil 1, the outer leg 54 portion is also pressed so that the reactor 10 does not tilt.

[0058] When the reactor 10 is pressed, a load is applied to the joint portion 56 of the E-shaped core members 51 and 52, and the joint portion 56 may be damaged, resulting in a poor joint, and in the worst case, it may be broken. However, in the present embodiment, the upper surface covering portion 71, the side surface covering portion 72, and the lower surface covering portion 73 of the mold resin 7 cover the upper surface, the side surface, and the lower surface of the joint portion 56, respectively, and the lower surface covering portion 73 of the mold resin 7 extends to the same length as the outer leg 54 and supports the joint portion 56. Therefore, even if a load is applied to the joint portion 56, damage to the joint portion 56 can be prevented, and a good joint state can be maintained.

[0059] Further, the mold resin 7 covers the two protruding portions 66 by the connecting portion 711 and is also formed inside the hollow portion 661 of the protruding portion 66. Therefore, the support of the joint portion 56 is stronger, and damage to the joint portion 56 can be prevented even when a load is applied.

[0060] Note that although the lower surface of the middle leg covering portion 61 does not form a lower surface covering portion 73 like the outer leg covering portion 62, since the coil 1 is mounted on the middle leg covering portion 61, the load due to pressing is absorbed by the coil 1. Therefore, even if the lower surface of the middle leg covering portion 61 is not reinforced like the lower surface covering portion 73, the problem of damage to the joint portion of the middle leg 53 is less likely to occur.

[0061] (Effect) As described above, the reactor 10 of the present embodiment includes a coil 1, a core 5 having outer legs 54 on which the coil 1 is not mounted, and a molded resin 7 that covers a part of the coil 1 excluding the lower surface 12 and a part of the core 5. The core 5 has a joint portion 56 in which E-shaped core members 51 and 52 are joined to at least the outer legs 54 around which the coil 1 is not wound. The molded resin 7 has an upper surface covering portion 71 that covers the upper surface of the joint portion 56, a side surface covering portion 72 that covers the side surface of the joint portion 56, and a lower surface covering portion 73 that covers the lower surface of the joint portion 56. The lower surface covering portion 73 extends in the extending direction of the outer leg 54.

[0062] As a result, the periphery of the joint portion 56 is covered by the upper surface covering portion 71, the side surface covering portion 72, and the lower surface covering portion 73, and the joint portion 56 is supported by the lower surface covering portion 73. In particular, the lower surface covering portion 73 extends in the extending direction of the outer leg 54, and the area for supporting the outer leg 54 is increased. Therefore, even when the reactor 10 is pressed when installed on the heat radiating member 8, it is firmly supported, and damage to the joint portion 56 and poor connection of the outer leg 54 can be prevented.

[0063] In particular, when the joint portion 56 is not adhered by an adhesive or the like, poor connection is likely to occur. However, as in the present embodiment, by covering the periphery of the joint portion 56 with the upper surface covering portion 71, the side surface covering portion 72, and the lower surface covering portion 73, the joint portion 56 can be supported even when the joint portion 56 is not adhered by an adhesive or the like, and poor connection can be prevented. Furthermore, since the adhesive and the adhesion process are not required, the cost can be reduced and the productivity can be improved.

[0064] The reactor 10 further includes a core coating resin 6 that coats the core 5, and the core coating resin 6 has an outer leg coating portion 62 that coats the outer leg 54. The outer leg coating portion 62 coats the outer legs 54 of the E-shaped core members 51 and 52 respectively, and the outer leg coating portion 62 that coats each E-shaped core member 51, 52 has a protruding portion 66 that protrudes from the upper surface of the outer leg coating portion 62. The protruding portion 66 has a hollow portion 661 with a space inside, and the mold resin 7 coats the protruding portion 66 and is also formed inside the hollow portion 661.

[0065] In this way, by forming the mold resin 7 inside the hollow portion 661 as well, the resistance to the force pressing the reactor 10 increases. Therefore, the joint portion 56 is prevented from being damaged, and poor contact of the outer leg 54 can be effectively prevented.

[0066] In particular, in the present embodiment, the mold resin 7 coats the pair of protruding portions 66 with one connecting portion 711. That is, the connecting portion 711 is formed on the joint portion 56. Therefore, the resistance to the force pressing the reactor 10 can be increased, and poor joint of the outer leg 54 can be more effectively prevented.

[0067] The mold resin 7 has an injection mark M formed at the position where the resin was injected during molding. The outer leg coating portion 62 has a groove portion 64 with a concave surface of the outer leg coating portion 62, and the groove portion 64 is formed on the upper surface of the outer leg coating portion 62 and extends from the injection mark M toward the side surface of the joint portion 56.

[0068] In this way, by forming the groove portion 64, the groove portion 64 can be used as a resin flow path during molding. Therefore, the injected resin is guided to the side surface of the joint portion 56 and flows from the side surface to the lower surface, so that the resin can reach every corner of the lower surface coating portion 73 that spreads in the extending direction of the outer leg 54. Therefore, the lower surface coating portion 73 with a desired strength can be molded.

[0069] In addition, in the present embodiment, the groove portion 64 has a wall 641 rising from the bottom surface of the groove portion 64, and the mold resin 7 covers the wall 641. Therefore, the area where the upper surface covering portion 71 covers the outer leg covering portion 62 increases, and the reinforcement strength of the joint portion 56 is improved. Further, the height of the wall 641 is lower than the side wall of the groove portion 64. Therefore, during mold molding, it does not become a resin barrier, and the resin is guided along the groove portion 64 to the side surface (notch 65) of the joint portion 56.

[0070] The injection mark M is provided on the upper surface of the yoke covering portion 63 in the extension region in the winding axis direction of the end surface orthogonal to the winding axis of the coil 1, and the mold resin 7 covers the groove portion 64.

[0071] In this way, by increasing the distance from the injection mark M to the joint portion 56, the area where the upper surface covering portion 71 covers the outer leg covering portion 62 further increases. Therefore, when the reactor 10 is pressed, the joint portion can be protected more firmly. Further, even if the distance from the injection mark M to the joint portion 56 becomes long, since the groove portion 64 can be used as a flow path, the resin can be guided to the lower mold during mold molding. Therefore, the lower surface covering portion 73 having a desired strength can be formed, and poor connection of the outer leg 54 can be prevented.

[0072] Further, the coil 1 is compressed in the winding axis direction during mold molding. If the injection mark M is provided in the extension region in the winding axis direction of the end surface orthogonal to the winding axis of the coil 1, by injecting the resin onto the end surface of the coil 1, the injection pressure of the resin can be utilized for pressing the coil 1. Therefore, the pressing member can be reduced, and the production cost can be reduced.

[0073] The outer leg covering portion 62 has a recess 67 provided on the lower surface of the outer leg covering portion 62, and the lower surface covering portion 73 has a convex portion 731 formed in the recess 67. Thereby, the area where the lower surface covering portion 73 contacts the outer leg covering portion 62 can be further increased. Therefore, the reinforcement strength of the joint portion 56 is further improved.

[0074] The outer leg covering portion 62 is provided on the side surface of the outer leg 54 and has a notch 65 that is cut out from the tip of the joint portion 56 toward the yoke portion 55 of the core 5. The notch 65 extends from the upper end to the lower end of the outer leg covering portion 62 and communicates with the groove portion 64. Further, the notch 65 is formed in the side covering portions 72 of the E-shaped core members 51 and 52 respectively. When the E-shaped core members 51 and 52 are joined, the notches 65 of each other communicate, and a large groove 651 is formed.

[0075] In this way, the outer leg covering portion 62 that covers the side surface of the outer leg 54 has a notch 65 and is recessed. In other words, the space between the outer leg covering portion 62 and the mold becomes wider. Therefore, during mold molding, the resin flowing to the upper end of the joint portion 56 easily flows into the space between the outer leg covering portion 62 and the mold. Therefore, it can spread to the lower surface of the outer leg covering portion 62. Thus, the lower surface covering portion 73 extending in the extending direction of the outer leg 54 can be molded, and the joint portion 56 can be firmly supported by the lower surface covering portion 73.

[0076] Also, the side covering portion 72 is formed in the notch 65, and the side surface of the side covering portion 72 and the outer leg covering portion 62 are flush. Therefore, since the side covering portion 72 does not protrude outward, an increase in the size of the reactor 10 can be prevented.

[0077] The outer leg covering portion 62 has a curved portion 621 whose tip corner is curved. Thereby, compared with the case where the tip corner of the outer leg covering portion 62 is refracted at 90 degrees, the contact area between the outer leg covering portion 62 and the side covering portion 72 can be increased. Therefore, the strength for reinforcing the joint portion 56 is increased.

[0078] (Other embodiments) In this specification, embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. The embodiments and their modifications are included in the scope and gist of the invention, as well as in the invention described in the claims and its equivalent scope.

[0079] In the above embodiment, as shown in FIG. 9, the heat dissipation member 8 was provided under the lower surface 12 of the coil 1, but the heat dissipation member 8 may also be provided under a pair of outer legs 54. In this case, the heat dissipation member 8 may be formed as a single piece, or a plurality of heat dissipation members 8 may be provided under the coil 1 and each outer leg 54.

[0080] In the above embodiment, the groove portion 64 was formed in the outer leg covering portion 62 that covers the E-shaped core member 52. However, when injecting resin from the side of the E-shaped core member 51 during mold molding, it is preferable to also form it in the outer leg covering portion 62 that covers the E-shaped core member 51.

[0081] In the above embodiment, the core 5 was covered with the core covering resin 6 and then covered with the mold resin 7. However, the core 5 does not necessarily need to be covered with the core covering resin 6. However, it is preferable to cover the core 5 with the core covering resin 6 and form the groove portion 64 and the notch 65 because it reaches every corner of the lower surface covering portion 73 during mold molding.

Explanation of Reference Numerals

[0082] 10 Reactor 1 Coil 11 Upper Surface 12 Lower Surface 13 Side Surface 14 Curved Surface 15 Lead Wire 2 Upper Surface Cover 3 Lower Surface Cover 31 Frame-like Portion 32 Wall Portion 4 End Surface Cover 5 cores 51, 52 E-shaped core members 53 middle legs 54 outer legs 55 yoke parts 56 joints 6 core coating resin 61 middle leg coating parts 62 outer leg coating parts 621 bent parts 63 yoke coating parts 64 groove parts 641 walls 65 notches 651 grooves 66 protrusions 661 hollow parts 67 recesses 7 mold resin 71 upper surface coating parts 711 connecting parts 72 side surface coating parts 73 lower surface coating parts 731 convex parts 8 heat dissipation members M injection marks

Claims

1. A coil, a core having legs on which the coil is not mounted, a molded resin that covers a part of the coil excluding the lower surface and a part of the core, and comprising: the core has a joint portion in which a plurality of divided core members are joined to at least the legs around which the coil is not wound, the molded resin has: an upper surface covering portion that covers the upper surface of the joint portion, a side surface covering portion that covers the side surface of the joint portion, a lower surface covering portion that covers the lower surface of the joint portion, and having: the lower surface covering portion extends in the extending direction of the leg and supports the joint portion, a reactor characterized by the above.

2. Further comprising a core covering resin that covers each of the divided core members, the core covering resin has a leg covering portion that covers the leg, the leg covering portion has a protruding portion that protrudes from the leg covering portion that covers the upper surface of the leg, the protruding portion has a hollow portion with a space inside, the molded resin covers the protruding portion and is also formed inside the hollow portion, a reactor according to claim 1, characterized by the above.

3. the molded resin has an injection mark that is a mark where resin was injected during molding, the leg covering portion has a groove portion where the surface of the leg covering portion is recessed, the groove portion is provided on the upper surface of the leg covering portion and extends from the injection mark toward the side surface of the joint portion, the molded resin covers the groove portion, a reactor according to claim 2, characterized by the above.

4. the injection mark is provided on the upper surface of the leg covering portion in an extended region in the winding axis direction of the end face orthogonal to the winding axis of the coil, a reactor according to claim 3, characterized by the above.

5. the groove portion has a wall rising from the bottom surface of the groove portion, the wall extends from the groove portion on the injection mark side toward the side surface of the joint portion, the molded resin covers the groove portion together with the wall, a reactor according to claim 3, characterized by the above.

6. the leg covering portion is provided on the lower surface of the leg covering portion and has a recess where the leg covering portion is recessed, the lower surface covering portion has a convex portion formed in the recess, a reactor according to any one of claims 2 to 5, characterized by the above.

7. the leg covering portion is provided on the side surface of the leg and has a notch cut from the tip of the leg covering portion toward the yoke portion of the core, the notch extends from the upper end to the lower end of the leg covering portion and communicates with the groove portion, When the divided core members are joined, one groove is formed by the notches of each other. The side covering portion is formed in the one groove. The reactor according to any one of claims 3 to 5, characterized in that.

8. The leg covering portion has a tip corner portion that is curved. The reactor according to any one of claims 2 to 5, characterized in that.

9. A method for manufacturing a reactor in which a coil and a core having a leg portion on which the coil is not mounted are covered with a molding resin, including a molding step of molding a part of the coil and a part of the core with a molding resin, comprising a core covering resin for covering the periphery of the core, the core has a joint portion where a plurality of divided core members are joined at least to the leg portion on which the coil is not wound, the molding resin, an upper surface covering portion that covers the upper surface of the joint portion, a side surface covering portion that covers the side surface of the joint portion, a lower surface covering portion that covers the lower surface of the joint portion, having, the lower surface covering portion extends in the extending direction of the leg portion and supports the joint portion, the core covering resin has a leg covering portion that covers the leg portion, the leg covering portion has a groove portion in which the surface of the leg covering portion is recessed, the groove portion is provided on the upper surface of the leg covering portion and extends toward the side surface of the joint portion, in the molding step, the molding resin is guided by the groove portion and flows into the joint portion. A method for manufacturing a reactor, characterized in that.

10. The leg covering portion is provided on the side surface of the leg portion and has a notch that is cut out from the tip end portion of the leg covering portion toward the yoke portion of the core, the notch extends from the upper end to the lower end of the leg covering portion and communicates with the groove portion, When the divided core members are joined, one groove is formed by the notches of each other. In the molding step, the molding resin that has flowed through the groove portion is guided by the one groove and flows into the space where the lower surface covering portion 73 is formed. The method for manufacturing a reactor according to claim 9, characterized in that.

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