Wire-wound coil component

Abstract

Provided is a wire-wound coil component in which, when a terminal electrode made of a metal plate is fixed to a flange of a core using an adhesive, a protruding part of the adhesive can be clearly distinguished from the flange in appearance, thereby making it difficult to cause erroneous recognition in an appearance inspection.　A flange (5) has an outer end surface (14) that extends in a direction orthogonal to an axial direction and that faces outward. A terminal electrode (9) includes a mounting piece (22) extending along the outer end surface (14). The terminal electrode (9) is fixed to the flange (5) by an adhesive (25) applied between the mounting piece (22) and the outer end surface (14). As viewed from the axial direction, the adhesive (25) has a protruding portion (26) that protrudes from the mounting piece (22) on the outer end surface (14), but the protruding portion (26) has a higher gloss than the outer end surface (14).

Description

Wound coil component

[0001] The present disclosure relates to a wound coil component having a structure in which a wire is wound around a core, and particularly relates to an attachment portion of a terminal electrode connected to the wire to the core.

[0002] As a technique of interest to the present disclosure, for example, there is one described in Japanese Patent Application Laid-Open No. 2023-125389 (Patent Document 1). Patent Document 1 describes a drum-shaped core having a winding core portion extending in the axial direction and flange portions provided at opposite ends of the winding core portion in the axial direction, a wire wound around the winding core portion, and terminal electrodes each formed of a metal plate connected to opposite ends of the wire.

[0003] The flange portion has an outer end face extending in a direction orthogonal to the axial direction and facing outward. On the other hand, the terminal electrode includes an attachment piece extending along the outer end face. The terminal electrode is fixed to the flange portion by an adhesive applied between the attachment piece and the outer end face of the flange portion. As the adhesive, one containing an epoxy resin is used.

[0004] Japanese Patent Application Laid-Open No. 2023-125389

[0005] When performing an appearance inspection when shipping the coil component, there may be carried out an inspection item in which it is determined whether the terminal electrode is attached at an appropriate position by observing the outer end face of the flange portion from the axial direction of the winding core axis. In this inspection, the position of the periphery of the outer end face of the flange portion and the position of the periphery of the attachment piece of the terminal electrode are observed, and it is determined whether these positional relationships are appropriate.

[0006] However, in this inspection, if the adhesive protrudes from the attachment piece of the terminal electrode on the outer end face of the flange portion, the periphery of the protruding portion may be erroneously recognized as the periphery of the outer end face of the flange portion. This is because when the core is made of a ceramic sintered body, it has a blackish color, but the adhesive containing an epoxy resin is transparent and thus has no appearance characteristics that can distinguish it from the core. That is, it is difficult to reliably distinguish between the core and the adhesive in an appearance inspection.

[0007] As a result, this can lead to the misidentification described above, causing good products to be mistakenly identified as defective, or conversely, defective products to be identified as good.

[0008] Therefore, the purpose of this disclosure is to provide a coil component that is less likely to cause misidentification due to excess adhesive as described above.

[0009] This disclosure relates to a wound coil component comprising a drum-shaped core made of a ceramic sintered body having a winding core portion extending in the axial direction and flanges provided at opposite ends of the winding core portion in the axial direction, a wire wound around the winding core portion, and terminal electrodes made of metal plates connected to opposite ends of the wire portion.

[0010] The flange has an outer end face that extends in a direction perpendicular to the axial direction and faces outward. The terminal electrode includes a mounting piece that extends along the outer end face. The terminal electrode is fixed to the flange by an adhesive applied between the mounting piece and the outer end face.

[0011] To solve the technical problems described above, the wound coil component according to this disclosure is characterized in that, when viewed from the axial direction, the adhesive has a portion that protrudes from the mounting piece at the outer end face, and the protruding portion has a higher gloss than the outer end face.

[0012] According to this disclosure, since the portion of the adhesive that protrudes from the mounting piece of the terminal electrode has a higher gloss than the outer end surface of the flange, the presence of the protruding portion of the adhesive can be visually clearly perceived on the outer end surface of the flange, which is made of a ceramic sintered body and therefore has a low surface gloss. Consequently, the periphery of the protruding portion of the adhesive is less likely to be mistakenly recognized as the periphery of the outer end surface of the flange, and the position of the periphery of the outer end surface of the flange can always be correctly recognized during the visual inspection of wound coil components. Therefore, it is possible to reduce the likelihood of misjudgments such as identifying good products as defective products or vice versa.

[0013] This is a perspective view showing the external appearance of a wound coil component 1 according to one embodiment of the present disclosure, with the mounting surface 11 of the flange portion 5 facing upwards, which is oriented toward the mounting substrate side of the wound coil component 1. This is an end view of the wound coil component 1 shown in Figure 1.

[0014] A wound coil component 1 according to one embodiment of the present disclosure will be described with reference to Figures 1 and 2. The illustrated wound coil component 1 constitutes, for example, a common mode choke coil.

[0015] The wound coil component 1 comprises a drum-shaped core 2. The core 2 has a winding core portion 3 extending in the axial direction AX and flange portions 5 provided at opposite ends of the winding core portion 3 in the axial direction AX. The core 5 is made of a ceramic sintered body such as ferrite or alumina. In the illustration, the cross-sectional shape of the winding core portion 3 is approximately square, but it may also be a polygonal shape such as a hexagon, a circular shape, an elliptical shape, or a combination thereof.

[0016] Two wires 7 and 8 are wound around the core 3. In a common mode choke coil, as is well known, the two wires 7 and 8 are wound in the same direction around the core 3. The wires 7 and 8 comprise a core wire made of a highly conductive metal such as copper, silver, or gold, and an insulating coating made of an electrically insulating resin such as polyamide-imide, polyurethane, or polyester-imide covering the core wire. It is preferable to use wires 7 and 8 with a diameter of 20 μm or more and 60 μm or less.

[0017] Each end of wires 7 and 8 is connected to a terminal electrode 9 made of a metal plate. As shown in Figure 1, the wound coil component 1 has four terminal electrodes 9. The four terminal electrodes 9 have the same or symmetrical shapes. More specifically, two symmetrical terminal electrodes 9 are arranged side by side in the width direction at one flange 5, and similarly, two symmetrical terminal electrodes 9 are arranged side by side in the width direction at the other flange 5.

[0018] The terminal electrode 9 is made of a metal plate made of a copper-based alloy such as phosphor bronze or tough pitch copper. Preferably, the metal plate that makes up the terminal electrode 9 is tin-plated. The metal plate has a thickness of, for example, 0.10 mm or more and 0.15 mm or less.

[0019] The flange portion 5 has a mounting surface 11 that faces the mounting substrate (not shown) side during mounting, a top surface 12 that faces the opposite side of the mounting surface 11, an inner end surface 13 that connects the mounting surface 11 and the top surface 12 and faces the winding core portion 3 side and positions the end of the winding core portion 3 in the axial direction AX, an outer end surface 14 that faces the opposite side of the inner end surface 13, and a first side surface 15 and a second side surface 16 that connect the inner end surface 13 and the outer end surface 14 and face in opposite directions to each other. The inner end surface 13 and the outer end surface 14 extend in a direction perpendicular to the axial direction AX.

[0020] A linearly extending convex portion 17 is provided on the outer end face 14 of the flange portion 5. The convex portion 17 extends in the height direction HD, which is perpendicular to the axial direction AX and is the direction in which the mounting surface 11 and the top surface 12 face each other.

[0021] Core 2, as an example, has dimensions of 3.5 mm in the axial direction AX, 2.6 mm in the width direction WD (the direction in which the first side surface 15 and the second side surface 16 face each other), and 1.4 mm in the height direction HD (the direction in which the mounting surface 11 and the top surface 12 face each other).

[0022] Each terminal electrode 9 has a mounting portion 20 that extends along the mounting surface 11 of the flange portion 5, and a mounting piece 22 that extends along the outer end surface 14 of the flange portion 5, connected to the mounting portion 20 via a bent portion 21 that covers the ridge where the mounting surface 11 and the outer end surface 14 of the flange portion 5 intersect. Furthermore, each terminal electrode 9 has a connecting piece 23 that extends from the mounting portion 20.

[0023] Each end of wires 7 and 8 is connected to the connecting piece 23 of the terminal electrode 9. For example, thermocompression bonding is used for this connection. In addition to thermocompression bonding, other connection methods such as laser welding may be used.

[0024] The configuration of the flange portion 5 shown in Figure 2 will be described below, but the configuration of the flange portion 5 on the opposite side of the flange portion 5 shown in Figure 2 is the same, so the explanation will be omitted.

[0025] The terminal electrode 9 is fixed to the flange portion 5 by adhesive 25 applied between the mounting piece 22 and the outer end surface 14 of the flange portion 5. As shown in Figure 2, the adhesive 25 has a portion 26 that protrudes from the mounting piece 22 on the outer end surface 14 of the flange portion 5. Note that in Figure 1, not only is the protruding portion 26 not shown, but the adhesive 25 itself is also not shown.

[0026] The adhesive 25 is mainly composed of a thermosetting resin, and preferably contains an epoxy resin. More specifically, the adhesive 25 is mainly composed of a bisphenol F type liquid epoxy resin or a bisphenol A type liquid epoxy resin, to which a curing agent is added. As the curing agent, for example, at least one selected from the group consisting of acrylic acid ester resins, melamine resins, urea resins, phenol resins, acid anhydride compounds, amine compounds, imidazole compounds, and active ester compounds is used.

[0027] The adhesive 25 is applied between the outer end surface 14 of the flange portion 5 and the mounting piece 22 of the terminal electrode 9. After the temperature is maintained near the melting point of the thermosetting resin contained in the adhesive 25 and it is melted, a glossy finish is produced when it is cured. For example, if it is a bisphenol A type epoxy resin, its melting point is 158°C, and a glossy finish is produced when the temperature is maintained near that point and it is cured.

[0028] Thus, because the adhesive 25 has a glossy appearance, the portion 26 that protrudes from the mounting piece 22 on the outer end surface 14 of the flange portion 5 can be visually distinguished with a high degree of gloss. In other words, the core 2, and more specifically the flange portion 5, are made of a ceramic sintered body, so their outer end surface 14 has a low degree of gloss and a dark color. In contrast, the portion 26 of the adhesive 25 that protrudes from the mounting piece 22 has a high degree of gloss, so it can be visually clearly distinguished on the outer end surface 14 of the flange portion 5. Specifically, when the wound coil component 1 is imaged by a camera from the angle shown in Figure 2 while irradiating it with light during visual inspection, the adhesive 25 reflects light and appears whitish, so it can be visually clearly distinguished from the flange portion 5 made of a ceramic sintered body.

[0029] Therefore, the periphery of the excess adhesive portion 26 is less likely to be mistakenly recognized as the periphery of the outer end face of the flange portion 5, and in the visual inspection of the wound coil component 1, the position of the periphery of the outer end face 14 of the flange portion 5 can always be correctly recognized, making it less likely to misjudge a good product as a defective product or vice versa. The visual inspection referred to here is an inspection that measures the distance between the periphery of the mounting piece 22 and the periphery of the outer end face 14, measures the mounting position and mounting angle of the terminal electrode 9, and determines whether it is a good product or not.

[0030] The wound coil component 1 may further include a top plate 27 that spans between the top surfaces 12 of the two flange portions 5. The top plate 27, as with the core 2, is preferably made of a ceramic sintered body such as ferrite or alumina. Alternatively, the top plate 27 may be made of a non-conductive material other than a ceramic sintered body, such as a resin containing ferrite powder, alumina powder, or metallic magnetic powder. The top plate 27 is bonded to the top surfaces 12 of the two flange portions 5 with an adhesive (not shown).

[0031] In this embodiment, the mounting piece 22 of the terminal electrode 9 has a side 29 that extends parallel to a linearly extending convex portion 17 on the outer end face 14 of the flange portion 5. As shown in Figure 2, the excess portion 26 of the adhesive 25 includes the portion located between the convex portion 17 and the aforementioned parallel-extending side 29 of the mounting piece 22. By positioning the excess portion 26 of the adhesive 25 in this manner, the position of the terminal electrode 9 can be stabilized, and the undesirable spreading of the excess portion 26 can be limited.

[0032] Furthermore, in this embodiment, the outer end face 14 of the flange portion 5 has a flat region 30 extending from the periphery of the mounting piece 22 of the terminal electrode 9 to the edge of the outer end face 14. Referring to Figure 2, the flat region 30 extending from the periphery of the mounting piece 22 to the edge of the outer end face 14 is located to the left of the left terminal electrode 9 and to the right of the right terminal electrode 9, respectively.

[0033] If the excess portion 26 of the adhesive 25 extends around the mounting piece 22 to the flat area 30, there is nothing to restrict the spread of the excess portion 26, and therefore the shape of the excess portion 25 can be diverse.

[0034] If differentiation based on the glossiness of the protruding portion 25 is not achieved as in this disclosure, and the shape of the protruding portion 25 is diverse, there is a possibility that the rate of misidentification of the periphery of the protruding portion 25 as the periphery of the outer end face 14 of the flange portion 5 may increase during the visual inspection of the wound coil component 1.

[0035] In contrast, if differentiation is achieved by the glossiness of the protruding portion 25, as in the present disclosure, the rate of misrecognition described above can be reduced even if the shape of the protruding portion 25 is diverse. Therefore, if the outer end face 14 of the flange portion 5 has a flat region 30 extending from around the mounting piece 22 of the terminal electrode 9 to the edge of the outer end face 14, the measures taken by the present disclosure become even more significant.

[0036] The above description relates to the embodiments illustrated in this disclosure, but various other modifications are possible within the scope of this disclosure.

[0037] For example, the adhesive 25 may be applied not only between the mounting piece 22 and the outer end face 14, but also between the mounting portion 20 and the mounting surface 11, and between the connecting piece 23 and the mounting surface 11.

[0038] Furthermore, the wound coil component to which this disclosure is directed may not only constitute a common mode choke coil as shown in the illustrated embodiment, but may also constitute a single coil, a transformer, a balun, or the like. Accordingly, the number of wires may be changed according to the function of the coil component, and the number of terminal electrodes provided on each flange may also be changed accordingly.

[0039] Furthermore, the embodiments described herein are illustrative, and partial substitution or combination of configurations is possible between different embodiments.

[0040] Embodiments of this disclosure include the following:

[0041] <1> A wound coil component comprising: a drum-shaped core made of a ceramic sintered body having a winding core portion extending in the axial direction and flange portions provided at opposite ends of the winding core portion in the axial direction; a wire wound around the winding core portion; and terminal electrodes made of metal plates connected to opposite ends of the wire, wherein the flange portion has an outer end face that extends in a direction perpendicular to the axial direction and faces outward; the terminal electrodes include a mounting piece extending along the outer end face; the terminal electrodes are fixed to the flange portion by an adhesive applied between the mounting piece and the outer end face; and, viewed from the axial direction, the adhesive has a portion that protrudes from the mounting piece on the outer end face, and the protruding portion has a higher gloss than the outer end face.

[0042] <2> The winding coil component according to <1>, wherein the ceramic sintered body is a sintered body of ferrite or alumina.

[0043] <3> The adhesive is a wound coil component according to <1> or <2>, comprising an epoxy resin.

[0044] <4> On the outer end face, a convex portion extending linearly is provided. The mounting piece has a side extending parallel to the convex portion. The protruding portion of the adhesive is located between the convex portion and the side of the mounting piece that extends parallel thereto. The wound coil component according to any one of <1> to <3>.

[0045] <5> The outer end face has a flat region from around the mounting piece to the edge of the outer end face. The protruding portion of the adhesive includes those that extend around the mounting piece and reach the flat region of the outer end face. The wound coil component according to any one of <1> to <4>.

[0046] 1 Wound coil component 2 Core 3 Bobbin part 5 Flange part 7, 8 Wire 9 Terminal electrode 14 Outer end face 17 Convex portion 22 Mounting piece 25 Adhesive 26 Protruding portion 29 Side of the mounting piece 30 Flat region AX Axial direction

Claims

1. A wound coil component comprising: a drum-shaped core made of a ceramic sintered body having a winding core portion extending in the axial direction and flange portions provided at opposite ends of the winding core portion in the axial direction; a wire wound around the winding core portion; and terminal electrodes made of metal plates connected to opposite ends of the wire, wherein the flange portion has an outer end face that extends in a direction perpendicular to the axial direction and faces outward; the terminal electrodes include a mounting piece extending along the outer end face; the terminal electrodes are fixed to the flange portion by an adhesive applied between the mounting piece and the outer end face; and, viewed from the axial direction, the adhesive has a portion that protrudes from the mounting piece on the outer end face, and the protruding portion has a higher gloss than the outer end face.

2. The wound coil component according to claim 1, wherein the ceramic sintered body is a sintered body of ferrite or alumina.

3. The winding coil component according to claim 1 or 2, wherein the adhesive comprises an epoxy resin.

4. The outer end face is provided with a linearly extending convex portion, the mounting piece has a side extending parallel to the convex portion, and the excess portion of the adhesive is located between the convex portion and the side extending parallel to the mounting piece, as described in any one of claims 1 to 3.

5. The winding coil component according to any one of claims 1 to 4, wherein the outer end face has a flat region extending from the periphery of the mounting piece to the edge of the outer end face, and the excess portion of the adhesive includes the periphery of the mounting piece extending to the flat region of the outer end face.

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