Coil device

Abstract

To provide a coil device capable of preventing a damage of a core or the like due to a stress even in the case where a moisture-proof coat or the like is coated after the mounting.SOLUTION: A coil device includes: a drum core having a winding core part, a first flange part connected to one end part of the winding core part, and a second flange part connecting the other end part of the winding core part; a connection core that is extended in nearly parallel to the winding core part and connects flange part upper surfaces of the first and second flange parts; a coil that is circulated to the winding core part; a first terminal electrode that includes a first terminal bottom part provided to a flange part lower surface of the first flange part, and in which one of the end part of the coil is electrically connected; a second terminal electrode that includes a second terminal bottom part provided to a flange part lower surface of the second flange part, and in which one of the other end part of the coil is electrically connected; and a non-magnetic case that has an upper bottom part that is opposite to the connection core from an upper direction and a pair of side surface parts that is extended to a lower direction from both end parts of a width direction of the upper bottom part and is faced to flange part side surfaces of the first and second flange parts and the coil.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a coil device that is mounted on various substrates and the like. [Background technology]

[0002] A substrate on which a coil device is mounted may be subjected to a process called moisture-proof coating, which widely covers the substrate surface. By coating the entire substrate, including the surface of the coil device, with resin, such substrates have the effect of preventing water droplets from adhering to the mounted components and substrate surface.

[0003] On the other hand, when a substrate on which a coil device is mounted is resin-coated, there is an issue that strong stress is generated in the coated coil device due to deformation of the resin. In particular, when a test involving severe temperature changes such as a heat cycle is performed, the stress generated by the deformation of the resin that constitutes the moisture-proof coating may cause damage such as cracks in the core of the coil device, which is problematic. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-281758 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure has been made in consideration of the above circumstances, and relates to a coil device that can prevent the problem of damage to the core, etc. due to stress, even when a moisture-proof coating, etc. is applied after mounting. [Means for solving the problem]

[0006] In order to achieve the above object, the coil device according to the present disclosure includes: A drum core having a winding core portion, a first flange portion connected to one end of the winding core portion, and a second flange portion connected to the other end of the winding core portion; a connection core extending substantially parallel to the winding core portion and connecting upper surfaces of the first flange portion and the second flange portion; A coil wound around the winding core; a first terminal electrode having a first terminal bottom portion provided on a flange portion underside of the first flange portion and electrically connected to at least one of the ends of the coil; a second terminal electrode having a second terminal bottom portion provided on a lower surface of the second flange portion and electrically connected to at least another one of the ends of the coil; The non-magnetic case has an upper bottom portion facing the connection core from above, and a pair of side portions extending downward from both widthwise ends of the upper bottom portion and facing the flange side surfaces of the first flange portion and the second flange portion and the coil.

[0007] In the coil device according to the present disclosure, the non-magnetic case having an upper bottom and a pair of side surfaces partially covers the other parts of the coil device, thereby protecting the weak parts of the connection core, drum core, etc. from the resin constituting the moisture-proof coating, and effectively preventing the problem of damage such as cracking of the core of the coil device. In addition, the non-magnetic case protects the core of the coil device from the stress transmitted from the moisture-proof coating, thereby preventing a decrease in inductance value due to stress generated in the core.

[0008] Also, for example, the nonmagnetic case does not have to overlap the first flange portion and the second flange portion when viewed from the winding axis direction of the winding core portion.

[0009] In this type of non-magnetic case, the first flange and the second flange are entirely exposed when viewed from the winding axis direction, making it easy to observe solder fillets and the like formed when mounting the coil device, and allowing for convenient determination of the quality of the mounting state using a camera or the like.

[0010] Also, for example, the lower end of the side portion may be located above the lower surface of the flange portion.

[0011] In such a coil device, an appropriate gap is formed between the lower end of the side portion and the mounting surface, so that the coil device can be more smoothly placed on the substrate and reflow mounted.

[0012] Also, for example, the magnetic head may include a resin portion provided inside the non-magnetic case and covering at least a portion of the connection core and the coil.

[0013] By having such a resin part, it is possible to more reliably protect the weaker parts of the core and coil from the resin that constitutes the moisture-proof coating, and to prevent damage to the core and coil even in an environment where severe temperature changes occur. In addition, when forming the resin part, the nonmagnetic case constitutes part of the wall that keeps the resin in a specified area, so that it is possible to effectively prevent excessive variation in the shape of the resin part and adhesion of the resin to unnecessary parts.

[0014] Also, for example, the first terminal electrode may have a first terminal connection portion provided on a flange upper surface of the first flange portion and to which at least one of the ends of the coil is connected, and a first terminal connection portion provided on a flange end surface of the first flange portion and connecting the first terminal connection portion and the first terminal bottom portion, The second terminal electrode may have a second terminal connection portion provided on an upper flange surface of the second flange portion and to which at least another of the coil ends is connected, and a second terminal connection portion provided on an end surface of the second flange portion and connecting the second terminal connection portion and the second terminal bottom portion.

[0015] In such a coil device, when mounted, solder creeps up to the first terminal connection portion and the second terminal connection portion provided on the end face of the flange portion, forming a suitable solder fillet, resulting in excellent mountability and even better visibility of the formed solder fillet.

[0016] Also, for example, the distance between the pair of side portions may be gradually narrowed from the position where the side portions connect to the upper base portion toward the lower ends of the side portions.

[0017] Such a non-magnetic case can more effectively protect the weaker portions of the core and coil from stress caused by deformation of the resin or the like that constitutes the moisture-proof coating. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is an overall perspective view of a coil device according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is an overall perspective view of the coil device shown in FIG. 1, viewed obliquely from below. [Diagram 3] FIG. 3 is a view of a core end surface of the coil device shown in FIG. 1, observed from the winding axis direction. [Figure 4] FIG. 4 is an exploded perspective view of the coil device shown in FIG. [Diagram 5] FIG. 5 is a view of the coil device shown in FIG. 1, with only the nonmagnetic case not shown, observed from the width direction perpendicular to the winding axis direction and the up-down direction. [Figure 6] FIG. 6 is a view of the coil device shown in FIG. 1 as viewed from above with the non-magnetic case and the connection core not shown. [Figure 7] FIG. 7 is an overall perspective view of a coil device according to the second embodiment of the present disclosure, viewed obliquely from below. [Figure 8] FIG. 8 is a cross-sectional view showing the internal state of a non-magnetic case in a coil device according to a first modified example. [Figure 9] FIG. 9 is a cross-sectional view showing the internal state of a non-magnetic case in a coil device according to a second modified example. [Figure 10] FIG. 10 is a conceptual diagram showing a state in which a substrate on which a coil device according to the present disclosure is mounted is subjected to a moisture-proof coating. [Figure 11] FIG. 11 is an exploded perspective view of a coil device according to the third embodiment of the present disclosure. [Figure 12] FIG. 12 is a view of a core end surface observed from the winding axis direction in a coil device according to a fourth embodiment of the present disclosure. [Figure 13]FIG. 13 is a view of the coil device shown in FIG. 12 observed from above with the non-magnetic case and the connection core not shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] First embodiment Hereinafter, the present disclosure will be described based on the embodiments shown in the drawings. The coil device 10 according to the present embodiment shown in Fig. 1 is used by being surface-mounted on, for example, a substrate 113 (see Fig. 10) or the like. Furthermore, although the coil device 10 described with reference to Figs. 1 to 6 is a common mode filter (common mode choke coil), the coil device according to the present disclosure is not limited to a common mode filter, and may be another inductor (see Fig. 11) or a coil device other than a common mode filter, such as a transformer.

[0020] Fig. 2 is an overall perspective view from diagonally below of the coil device 10 shown in Fig. 1. As shown in Fig. 1 and Fig. 2, the coil device 10 has a drum core 20, a connection core 30, a coil 40, a first terminal electrode 50, a second terminal electrode 60, a third terminal electrode 70, a fourth terminal electrode 80, and a non-magnetic case 90.

[0021] As shown in Fig. 1 and Fig. 2, the core in the coil device 10 is formed by combining two cores, a drum core 20 and a connection core 30. Fig. 5 is a view of the coil device 10 shown in Fig. 1, in which only the non-magnetic case 90 is not shown, as viewed from a width direction D3 perpendicular to the up-down direction D1 and the winding axis direction D2. In the description of the coil device 10, the direction perpendicular to the mounting surface of the coil device 10 is defined as the up-down direction D1 (Z-axis direction), the direction perpendicular to the up-down direction D1 and in which the winding core part 22 of the drum core 20 serving as the winding axis of the coil 40 extends is defined as the winding axis direction D2 (X-axis direction), and the direction perpendicular to the up-down direction D1 and the winding axis direction D2 is defined as the width direction D3 (Y-axis direction).

[0022] 5, the drum core 20 has a winding core portion 22, a first flange portion 24 connected to one end portion 22a of the winding core portion 22 in the winding axis direction D2, and a second flange portion 26 connected to the other end portion 22b of the winding core portion 22 in the winding axis direction D2. The winding core portion 22 has a substantially rectangular parallelepiped outer shape extending in the winding axis direction D2, but the shape of the winding core portion 22 is not limited to a rectangular parallelepiped and may be a cylindrical shape or another shape.

[0023] The first flange 24 and the second flange 26 are disposed on both sides of the winding core 22 in a generally symmetrical manner. FIG. 3 is a view of the coil device 10 as viewed along the winding axis direction D2, and FIG. 4 is an exploded perspective view of the coil device 10. As shown in FIGS. 1 to 5, the first flange 24 and the second flange 26 have a generally rectangular parallelepiped outer shape in which the cross-sectional area of ​​a section perpendicular to the winding axis direction D2 is larger than that of the winding core 22. However, as described later, each surface of the first flange 24 and the second flange 26 may have an uneven surface, or may have a shape different from a simple rectangular parallelepiped shape. In addition, the first flange 24 and the second flange 26 may have a polygonal prism shape or a cylindrical shape other than a rectangular parallelepiped shape.

[0024] As shown in Fig. 5, the connection core 30 extends approximately parallel to the winding core portion 22 and connects the flange upper surfaces 24a, 26a of the first flange portion 24 and the second flange portion 26 to each other. Fig. 6 is a plan view of the coil device 10 shown in Fig. 1, in which the non-magnetic case 90 and the connection core 30 are not shown, and the drum core 20 and the like are viewed from above. As shown in Fig. 6, protruding surfaces that protrude upward are formed in the center portions in the width direction D3 of the flange upper surface 24a of the first flange portion 24 and the flange upper surface 26a of the second flange portion 26, and the lower surface of the connection core 30 shown in Fig. 5 is connected to these protruding surfaces.

[0025] As shown in Fig. 4, the connection core 30 has a rectangular plate shape or a substantially rectangular parallelepiped shape that covers the upper part of the drum core 20, but the shape of the connection core 30 is not limited to only the plate shape as shown in Fig. 4. In the coil device 10, the connection core 30 is fixed to the drum core 20 by adhesion or the like, but the method of connecting the connection core 30 and the drum core 20 is not limited to only adhesion.

[0026] The drum core 20 and the connection core 30 can be made of a magnetic material such as, for example, ferrite or a metal such as iron, but are not limited thereto. The drum core 20 and the connection core 30 may be made of the same material or different materials.

[0027] As shown in Figures 5 and 6, the coil 40 winds around the winding core portion 22 of the drum core 20. As shown in Figure 6, the coil 40 has two wires, and has four ends, namely, a coil first end 41, a coil second end 42, a coil third end 43, and a coil fourth end 44. The wires included in the coil 40 are composed of coated conductor wires or the like. The number of wires included in the coil 40 is not particularly limited, and may include one wire (see Figure 11) or three or more wires.

[0028] As shown in Fig. 2, the coil device 10 has four terminal electrodes consisting of a first terminal electrode 50, a second terminal electrode 60, a third terminal electrode 70, and a fourth terminal electrode 80. The first terminal electrode 50 has a first terminal bottom portion 52 provided on the flange lower surface 24b, which is the surface facing downward in the first flange 24. In addition, as shown in Figs. 5 and 6, a coil first end portion 41, which is one of the ends of the coil 40, is electrically connected to the first terminal electrode 50.

[0029] 3 to 5, the first terminal electrode 50 has a first terminal connection portion 54 that is provided on the flange upper surface 24a, which is the surface facing upward in the first flange 24, and is connected to the coil first end 41, which is one of the ends of the coil 40. As shown in Fig. 5 and Fig. 6, the first terminal connection portion 54 is located at the end of the flange upper surface 24a in the width direction D3, and is provided in a recess that is lower in height than the center.

[0030] 5, the first terminal electrode 50 has a first terminal connection portion 56 that is provided on a flange end surface 24e, which is a surface of the first flange 24 that faces outward in the winding axis direction D2, and connects the first terminal connection portion 54 and the first terminal bottom portion 52. Thus, the first terminal electrode 50 has a substantially U-shaped configuration in which the first terminal connection portion 54 and the first terminal bottom portion 52 sandwich the first flange 24 from above and below, and the first terminal connection portion 56 connects the first terminal connection portion 54 and the first terminal bottom portion 52.

[0031] 2 and 3, like the first terminal electrode 50, the third terminal electrode 70 has a third terminal bottom portion 72 provided on the flange lower surface 24b of the first flange portion 24, a third terminal connection portion 74 provided on the flange upper surface 24a of the first flange portion 24, and a third terminal connection portion 76 provided on the flange end surface 24e of the first flange portion 24. As shown in Fig. 6, the third terminal connection portion 74 is connected to the coil third end portion 43, which is the other one of the ends of the coil 40, and the third terminal electrode 70 is electrically connected to the coil third end portion 43.

[0032] As shown in Figures 3 and 6, the third terminal electrode 70 is arranged approximately symmetrically to the first terminal electrode 50 with respect to the center position of the width direction D3 of the first flange portion 24, and the third terminal connection portion 74 is arranged in a recess in the flange upper surface 24a.

[0033] 2 and 5, the second terminal electrode 60 has a second terminal bottom portion 62 provided on the flange lower surface 26b, which is the surface facing downward in the second flange 26. In addition, as shown in Fig. 5 and 6, the second terminal electrode 60 is electrically connected to the second coil end portion 42, which is the other one of the ends of the coil 40.

[0034] 4 and 5, the second terminal electrode 60 has a second terminal connection portion 64 that is provided on the flange upper surface 26a, which is the surface facing upward in the second flange 26, and is connected to the second coil end 42, which is the other one of the ends of the coil 40. As shown in Fig. 5 and 6, the second terminal connection portion 64 is located at the end of the flange upper surface 26a in the width direction D3, and is provided in a recess that is lower in height than the center portion.

[0035] 5, the second terminal electrode 60 has a second terminal connection portion 66 that is provided on the flange end surface 26e, which is the surface of the second flange 26 that faces outward in the winding axis direction D2, and connects the second terminal connection portion 64 and the second terminal bottom portion 62. Therefore, the second terminal electrode 60 has a substantially U-shaped shape in which the second terminal connection portion 64 and the second terminal bottom portion 62 sandwich the second flange 26 from above and below, and the second terminal connection portion 66 connects the second terminal connection portion 64 and the second terminal bottom portion 62.

[0036] 2 and 6, like the second terminal electrode 60, the fourth terminal electrode 80 has a fourth terminal bottom portion 82 provided on the flange lower surface 26b of the second flange portion 26, a fourth terminal connection portion 84 provided on the flange upper surface 26a of the second flange portion 26, and a fourth terminal connection portion 86 provided on the flange end surface 26e of the second flange portion 26. As shown in Fig. 6, the fourth terminal connection portion 84 is connected to the fourth coil end portion 44, which is the other one of the ends of the coil 40, and the fourth terminal electrode 80 is electrically connected to the fourth coil end portion 44.

[0037] As shown in Figures 2 and 6, the fourth terminal electrode 80 is arranged approximately symmetrically to the second terminal electrode 60 with respect to the center position of the width direction D3 of the second flange portion 26, and the fourth terminal connection portion 84 is arranged in a recess in the flange upper surface 26a.

[0038] 5 and 6, the second terminal electrode 60 is disposed approximately symmetrically with respect to the first terminal electrode 50 with respect to the center position of the drum core 20 in the winding axis direction D2. Similarly, the fourth terminal electrode 80 is disposed approximately symmetrically with respect to the third terminal electrode 70 with respect to the center position of the drum core 20 in the winding axis direction D2.

[0039] 2 and 4, the first to fourth terminal bottom portions 52, 62, 72, 82 of the first to fourth terminal electrodes 50, 60, 70, 80 are located at the lowest position in the coil device 10. For example, the coil device 10 is mounted on a substrate or the like by connecting the first to fourth terminal bottom portions 52, 62, 72, 82 to a land pattern via reflow soldering.

[0040] The first to fourth terminal electrodes 50, 60, 70, 80 are formed by fixing a plate material made of a metal such as a copper alloy such as phosphorus bronze to the drum core 20 via an adhesive or the like. However, the first to fourth terminal electrodes 50, 60, 70, 80 are not limited to those made by processing a metal plate material, and may be made by metal paste, metal plating, or the like. The number of terminal electrodes of the coil device 10 is not limited to only four as shown in FIG. 2 and the like, and may be two, three, five or more. The number of ends 41 to 44 of the coil 40 connected to each terminal electrode is not limited to only one, and a plurality of ends 41 to 44 may be connected to one terminal electrode.

[0041] 1 to 4, a non-magnetic case 90 of the coil device 10 is attached from above to other parts of the coil device 10. The non-magnetic case 90 has an upper bottom portion 92 that faces the connection core 30 from above, and a pair of side portions, a first side portion 94 and a second side portion 96, that extend downward from both ends of the upper bottom portion 92 in the width direction D3.

[0042] 4, the first side surface portion 94 faces on the inside of flange side surfaces 24c and 26c, which are surfaces of the first flange portion 24 and the second flange portion 26 facing the width direction D3, and the coil 40. The second side surface portion 96 faces on the inside of flange side surfaces 24d and 26d, which are surfaces of the first flange portion 24 and the second flange portion 26 facing the width direction, and the coil 40 (see FIG. 6).

[0043] As shown in Figs. 1 to 3, the non-magnetic case 90 has a generally U-shaped shape with an opening facing downward. The non-magnetic case 90 does not overlap the first flange 24 and the second flange 26 when viewed from the winding axis direction D2 of the winding core 22. As shown in Figs. 1 to 3, in the coil device 10, the flange end face 24e of the first flange 24 and the flange end face 26e of the second flange 26 are not hidden by the non-magnetic case 90. Therefore, in the coil device 10, it is easy to observe solder fillets formed on the first to fourth terminal connection parts 56, 66, 76, 86 and the first to fourth terminal bottom parts 52, 62, 72, 82, etc. when the coil device 10 is mounted, and it is possible to suitably judge whether the mounting state is good or bad using a camera or the like.

[0044] 3, side surface lower ends 94a, 96a, which are the lower ends of the first side surface portion 94 and the second side surface portion 96, are located above the flange lower surfaces 24b, 26b. This creates an appropriate height difference between the first to fourth terminal bottoms 52, 62, 72, 82 constituting the mounting surface and the lower end of the non-magnetic case 90, preventing a problem in which the non-magnetic case 90 gets in the way during the placement and reflow process when mounting the coil device 10.

[0045] The first side portion 94 and the second side portion 96 of the nonmagnetic case 90 may be parallel to each other, or may be non-parallel to each other. As shown in Fig. 4, the distance between the pair of first and second side portions 94, 96 may be gradually narrowed from the position where the first and second side portions 94, 96 connect to the upper bottom portion 92 toward the side portion lower ends 94a, 96a. The distance W2 between the side portion lower ends 94a, 96a in the width direction D3 may be 0.9 to less than 1.0 times the distance W1 between the first and second side portions 94, 96 at the position where the first and second side portions 94, 96 connect to the upper bottom portion 92, and may be 0.95 to 0.99 times.

[0046] Since the non-magnetic case 90 gradually narrows toward the lower ends 94a, 96a of the side surfaces, it becomes possible to precisely align the center position in the width direction D3 of the non-magnetic case 90 with the center position in the width direction D3 of the drum core 20. Such a coil device 10 has high dimensional accuracy, and the first to fourth terminal bottom portions 52, 62, 72, 82 can be precisely aligned with the land pattern when placed on the mounting board.

[0047] The thickness (average value) of the non-magnetic case 90 is not particularly limited, but can be, for example, about 10 to 200% of the thickness of the connection core 30, or about 20 to 100% of the thickness of the connection core 30. By making the thickness of the non-magnetic case 90 a predetermined value or more, it is possible to suitably block stress transmitted to the connection core 30 etc. from a moisture-proof coating etc. that covers the coil device 10 after mounting, and by making the thickness of the non-magnetic case 90 a predetermined value or less, it is possible to prevent the coil device 10 from becoming large.

[0048] The material of the non-magnetic case 90 is not particularly limited as long as it is a non-magnetic material, and examples of the material include resins such as polycarbonate, polyethylene terephthalate, and polyether ether ketone. The non-magnetic case 90 can be manufactured by injection molding, machining, or a combination of these, but the manufacturing method of the non-magnetic case 90 is not particularly limited. The non-magnetic case 90 is a case that has a predetermined shape before being assembled to the connection core 30, etc., and a predetermined gap is formed between the non-magnetic case 90 and the coil 40. This is different from the coating resin that is applied to the surfaces of the coil 40 and the drum core 20 as an uncured resin and then cured.

[0049] The coil device 10 is manufactured, for example, by the following procedure. That is, in manufacturing the coil device 10, first, the drum core 20 is prepared, the first to fourth terminal electrodes 50, 60, 70, 80 are formed on the first flange portion 24 and the second flange portion 26, and then a wire is wound around the winding core portion 22 and the ends are fixed to the first to fourth terminal electrodes 50, 60, 70, 80 to form the coil 40. Furthermore, the connection core 30 is fixed to the drum core 20 on which the first to fourth terminal electrodes 50, 60, 70, 80 and the coil 40 are formed, and then the non-magnetic case 90 is fixed to the drum core 20 and the connection core 30 to obtain the coil device 10.

[0050] The non-magnetic case 90 can be fixed to the drum core 20 and the connection core 30, for example, by fixing the lower surface of the upper bottom portion 92 and the upper surface of the connection core 30 with an adhesive or the like. In addition, when a resin part 118 is formed inside the non-magnetic case 90 as in the coil device 110 (see FIG. 7) shown in the second embodiment, the non-magnetic case 90 may be fixed to the drum core 20 and the connection core 30 via the resin part 118.

[0051] In addition, the coil device 10 may be used after being mounted on a substrate or the like, coated together with the substrate surface with a coating resin called a moisture-proof coat or the like. Fig. 10 is a conceptual diagram illustrating a state in which the coil device 10 mounted on the substrate 113 is coated with a coating resin 517. The coating resin 517 shown in Fig. 10 is formed by pouring uncured coating resin onto the mounting surface side of the substrate 113 after the coil device 10 and other electronic components are mounted on the substrate 113, and curing the resin, so that the mounting components including the coil device 10 and the mounting surface of the substrate 113 are embedded in the coating resin 517.

[0052] 1, the periphery of the portion of the coil device that directly contacts the coating resin 517 will be subject to a large deformation stress due to the difference in linear expansion coefficient with the coating resin 517. In particular, if the non-magnetic case 90 is not provided, the connection core 30 of the coil device 10 will be in contact with the coating resin 517 over a wide area, and will be subjected to a large force from the coating resin 517, which may cause damage such as cracks and chips around the connection core 30 and the flanges 24, 26 of the drum core 20 that fixes the connection core 30.

[0053] In contrast, in the coil device 10 having the non-magnetic case 90 as shown in Figs. 1 to 4, the non-magnetic case 90 is interposed between the connection core 30 and the coating resin 517, and stress due to deformation of the coating resin 517 can be prevented from being transmitted to the connection core 30 and the drum core 20. Therefore, the non-magnetic case 90 protects the weak parts of the connection core 30 and the drum core 20 from the coating resin 517 constituting the moisture-proof coat, and can effectively prevent the problem of damage such as cracks occurring in the cores 20, 30 of the coil device 10. In addition, in the coil device 10, the non-magnetic case 90 protects the cores 20, 30, and therefore can effectively prevent a decrease in inductance value due to stress generation in the cores 20, 30.

[0054] Second embodiment 7 is an overall perspective view of a coil device 110 according to a second embodiment of the present disclosure, viewed from diagonally below. The coil device 10 differs from the coil device 10 according to the first embodiment in that it has a resin part 118 inside the non-magnetic case 90, but is otherwise similar to the coil device 10. In the description of the coil device 110 according to the second embodiment, only the differences from the coil device 10 will be described, and the same reference numerals will be used to denote the commonalities with the coil device 10, and description thereof will be omitted.

[0055] 7 is provided inside the non-magnetic case 90 (below the upper bottom portion 92, in the region between the first side surface portion 94 and the second side surface portion). The resin portion 118 covers the winding core portion 22 of the drum core 20 and at least a portion of the coil 40 wound around the winding core portion 22.

[0056] The resin portion 118 is provided inside the non-magnetic case 90 so as to fill a predetermined area from the lower surface of the upper bottom portion 92 to the lower ends 94a, 96a of the side portions, and the resin portion 118 covers not only the winding core portion 22 but also at least a portion of the connection core 30 and the first to fourth ends 41 to 44 of the coils (see Figure 4, etc.).

[0057] Resin portion 118 is provided between first flange 24 and second flange 26 in winding axis direction D2. Therefore, flange end faces 24e, 26e and flange lower faces 24b, 26b of first flange 24 and second flange 26, terminal bottoms 52, 62, 72, 82 and terminal connecting portions 56, 66, 76, 86 of terminal electrodes 50, 60, 70, 80 are exposed from resin portion 118.

[0058] The resin constituting resin portion 118 is not particularly limited, but while acrylic or epoxy resins are often used as coating resin 517 shown in FIG. 10, the resin constituting resin portion 118 is preferably a resin having a lower Young's modulus than coating resin 517, and for example, a silicone-based resin can be used.

[0059] If the coil device did not have the non-magnetic case 90 and the resin part 118, the coating resin 517 shown in Fig. 10 would flow under the connection core 30, and the coating resin 517 may come into contact with the first to fourth ends 41 to 44 of the coil shown in Fig. 6. In this case, the first to fourth ends 41 to 44 of the coil are subjected to a large deformation stress due to the difference in the linear expansion coefficient between the coating resin 517 and the wires constituting the coil 40, and in an environment where a severe temperature difference occurs, damage such as breakage may occur.

[0060] In contrast, in coil device 110 having non-magnetic case 90 and resin part 118, coil first to fourth ends 41 to 44 are covered by resin part 118 and are protected from direct contact with coating resin 517. Therefore, in coil device 110, weaker parts of cores 20, 30 and coil 40 are more reliably protected from coating resin 517 constituting the moisture-proof coat, and damage to cores 20, 30 and coil 40 can be prevented even in an environment where severe temperature changes occur.

[0061] Although there is a difference in the linear expansion coefficient between the resin portion 118 and the cores 20, 30, and the coil 40, the resin portion 118 filled in a narrow region has a suppressed amount of deformation, unlike the coating resin 518 shown in Fig. 10, and therefore the stress transmitted to the cores 20, 30, and the coil 40 can be controlled within a predetermined range. In addition, by forming the resin portion from a soft resin such as silicone resin, the stress transmitted to the cores 20, 30, and the coil 40 can be suppressed.

[0062] 7 can be produced by pouring uncured resin into non-magnetic case 90 and curing it after producing coil device 10 shown in Fig. 2. Non-magnetic case 90 constitutes a part of a wall that keeps resin in a predetermined area when forming resin part 118, and therefore can effectively prevent excessive variation in the shape of resin part 118 and adhesion of resin to unnecessary parts.

[0063] Note that the resin part 118 shown in FIG. 7 completely covers the coil 40 and the winding core part 22, but the shape of the resin part 118 is not limited to the state shown in FIG. 7. FIG. 8 is a cross-sectional view of a coil device 210 according to a first modified example, and FIG. 9 is a cross-sectional view of a coil device 310 according to a second modified example. The coil devices 210 and 310 shown in FIG. 8 and FIG. 9 are similar to the coil device 110 shown in FIG. 7, except that the shapes of the resin parts 218 and 318 in the coil devices 210 and 310 are different from the resin part 118 shown in FIG. 7. Regarding the coil devices 210 and 310, only the differences from the coil device 110 will be described, and the description of the commonalities with the coil device 110 will be omitted.

[0064] 8, a lower surface 218a of the resin part 218 is at substantially the same height as the center of the winding core part 22, and parts of the coil 40 and the winding core part 22 are exposed from the resin part 218. In a coil device 310 according to a second modified example shown in FIG. 9, a lower surface 318a of the resin part 318 is at substantially the same height as the upper surface of the winding core part 22, and parts of the coil 40 and the entire winding core part 22 are exposed from the resin part 218.

[0065] In such coil devices 210, 310, the resin part 218 protects the weaker parts of the cores 20, 30 and the coil 40 (for example, the first to fourth ends 41-44 of the coils), and can prevent damage to the cores 20, 30 and the coil 40 even in an environment where severe temperature changes occur. In addition, the coil devices 110, 210, 310 have the same effects as the coil device 10 in terms of the points they have in common with the coil device 10.

[0066] Although the coil devices 10, 110, 210, and 310 according to the present disclosure have been described above with reference to a number of embodiments, it goes without saying that the coil devices 10, 110, 210, and 310 according to the present disclosure are not limited to the above-described embodiments, but include many other embodiments and modifications. For example, in the coil device 10, either the first terminal electrode 50 or the third terminal electrode 70 may be the "first terminal electrode" or the "third terminal electrode." The same is true for the second terminal electrode 60 and the fourth terminal electrode 80.

[0067] Third embodiment 11 is an exploded perspective view of a coil device 410 according to a third embodiment of the present disclosure. The coil device 410 has a non-magnetic case 490, a drum core 420, a connection core 430, a coil 440, a first terminal electrode 450, and a second terminal electrode 460. In the coil device 410, one end of the coil 440 is electrically connected to the first terminal electrode 450, and the other end is electrically connected to the second terminal electrode 460.

[0068] 3 in that coil 440 includes one wire, has two terminal electrodes, a first terminal electrode 450 and a second terminal electrode 460, and has a connection portion between coil 440 and first and second terminal electrodes 450, 460 disposed on the underside of the flange. However, coil device 410, like coil device 110, has non-magnetic case 490 interposed between connection core 30 etc. and coating resin 517, so that the problem of stress due to deformation of the coating resin being transmitted to connection core 430 and coil 440 can be prevented even when coil device 410 is coated with coating resin such as moisture-proof coating after being mounted on a substrate.

[0069] In this manner, the technology of the present disclosure can also be applied to an inductor such as the coil device 410. In addition, the coil device 410 has the same effects as the coil device 10 in terms of the points in common with the coil device 10.

[0070] Fourth embodiment 12 is a view of a core end surface viewed from the winding axis direction in a coil device 510 according to a fourth embodiment of the present disclosure. The coil device 510 is similar to the coil device 10 shown in FIGS. 1 to 6 in the shapes of the first to fourth terminal connection parts 554-584 in the first to fourth terminal electrodes 550-580.

[0071] Fig. 13 is a view of the coil device 510 shown in Fig. 12 observed from above with the non-magnetic case 90 and the connection core 30 not shown. As shown in Fig. 13, the first to fourth terminal connection parts 554-584 have folded-back parts folded back from the central part (inner part) of the flange upper faces 24a, 26a in the width direction D3 to the flange side faces 24c, 26c which are the outer sides. In this regard, in the coil device 10 shown in Fig. 6, the first to fourth terminal connection parts 54-84 have folded-back parts folded back from the flange side faces 24c, 26c which are the outer sides in the width direction D3 to the central part (inner part) of the flange upper faces 24a, 26a.

[0072] The shapes of the first to fourth terminal connection parts 54-83, 554-584 in the first to fourth terminal electrodes 50-80, 550-580 are not particularly limited, but by having a shape that is folded back outward from the center side of the flange upper surfaces 24a, 26a as shown in Fig. 13, it is possible to improve the engagement strength when the first to fourth terminal connection parts 554-584 and the coil first to fourth ends 41-44 are temporarily fixed. In addition, the coil device 510 according to the fourth embodiment has the same effects as the coil device 10 according to the first embodiment in terms of the points in common with the coil device 10 according to the first embodiment. [Explanation of symbols]

[0073] 10, 110, 210, 310, 410, 510... Coil device 20, 420...Drum core 22…Coil 22a...One end 22b...the other end 24…First flange 26…Second flange 24a, 26a...Top surface of flange 24b, 26b…bottom side of tsuba 24c, 26c…flange side 24d, 26d…flange side 24e, 26e...Flame end face 30, 430…Connection core 40, 440…Coil 41...Coil first end 42...Second coil end 43…Third end of coil 44…Fourth end of coil 50, 450, 550...1st terminal electrode 52…First terminal bottom 54, 554...1st terminal connection part 56…First terminal connection part 60, 460, 560…Second terminal electrode 62…2nd terminal bottom 64, 564...2nd terminal connection part 66…Second terminal connection part 70…Third terminal electrode 72…3rd terminal bottom 74, 574...3rd terminal connection part 76…Third terminal connection part 80…4th terminal electrode 82…4th terminal bottom 84, 584...4th terminal connection part 86…4th terminal connection part 90, 490...Non-magnetic case 92...Top bottom 94…First side part 94a…Bottom end of side surface 96…Second side part 96a…Bottom end of side surface D2…Reel direction D3: Width direction D1…Vertical direction 517…Coating resin 118, 218, 318...Resin part 218a, 318a...bottom surface

Claims

1. A drum core having a winding core portion, a first flange portion connected to one end of the winding core portion, and a second flange portion connected to the other end of the winding core portion; a connection core extending substantially parallel to the winding core portion and connecting upper surfaces of the first flange portion and the second flange portion; A coil wound around the winding core; a first terminal electrode having a first terminal bottom portion provided on a flange portion underside of the first flange portion and electrically connected to at least one of the ends of the coil; a second terminal electrode having a second terminal bottom portion provided on a lower surface of the second flange portion and electrically connected to at least another one of the ends of the coil; A coil device having a non-magnetic case having an upper bottom portion facing the connection core from above, and a pair of side portions extending downward from both widthwise ends of the upper bottom portion and facing the flange side surfaces of the first flange portion and the second flange portion and the coil.

2. The coil device according to claim 1 , wherein the non-magnetic case does not overlap the first flange portion and the second flange portion when viewed in the winding axis direction of the winding core portion.

3. The coil device according to claim 1 , wherein a lower end of the side portion is located above a lower surface of the flange portion.

4. The coil device according to claim 1 , further comprising a resin portion provided inside the non-magnetic case and covering at least a portion of the connection core and the coil.

5. the first terminal electrode has a first terminal connection portion provided on an upper flange surface of the first flange portion and connected to at least one of the ends of the coil, and a first terminal connection portion provided on an end surface of the first flange portion and connecting the first terminal connection portion and the first terminal bottom portion, 3. The coil device according to claim 2, wherein the second terminal electrode has: a second terminal connection portion provided on an upper flange surface of the second flange portion and to which at least another of the ends of the coil is connected; and a second terminal connection portion provided on an end surface of the second flange portion and connecting the second terminal connection portion and the second terminal bottom portion.

6. The coil device according to claim 2 , wherein a distance between the pair of side portions gradually narrows from a position where the side portions connect to the upper base portion toward the lower ends of the side portions.

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