Coil component

Abstract

To improve a fixture strength of a terminal electrode in a coil component where a terminal electrode including a conductor film consisting of a sintered body of conductive paste is provided on a mounting surface, which is directed toward the side of a mounting substrate, in a core.SOLUTION: Projections 17-20 for positioning tops 21-24 inside of edges of mounting surfaces 9, 10, 13 and 14 in a width direction orthogonal to an axial direction of a winding core part are provided on the mounting surfaces. The projections form inclined surfaces 27-30 which extend so as to be lower from the tops toward the edges. When conductive paste to be conductor films 37-40 is applied to the mounting surfaces 9, 10, 13 and 14 by e.g., a dipping method, since the projections 17-20 are provided on the mounting surfaces, an application thickness of the conductive paste can be increased and the conductor films 37-40 consisting of a sintered body of the conductive paste can be formed thick, thereby improving a fixture strength of terminal electrodes 33-36 each including the conductor film to the mounting surfaces.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a coil component comprising a core having a winding core portion around which a wire is wound and flange portions provided at each end of the winding core portion in the axial direction, and terminal electrodes provided on the flange portions to which the wire is connected, and in particular to the structure of the portion of the flange portion where the terminal electrodes are provided. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open No. 2017-41589 (Patent Document 1) describes a coil component including a core having a winding core around which a wire is wound and flanges provided at each end of the winding core. A terminal electrode is provided on the mounting surface of the flange that faces the mounting board during mounting. A wire is connected to the terminal electrode by thermocompression bonding. The terminal electrode includes a conductive film made of a sintered body of a conductive paste applied to the mounting surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-41589 Summary of the Invention [Problem to be solved by the invention]

[0004] The conductive paste to be used to form the conductor film on the terminal electrodes is applied to the mounting surface by, for example, a dipping method. In the coil component described in Patent Document 1, the mounting surface on which the terminal electrodes are provided is flat, as shown in the drawings in the document. When the mounting surface is flat, the conductive paste applied thereto may not be thick enough. In this case, there is a problem in that the adhesive strength of the terminal electrodes to the mounting surface is reduced.

[0005] Therefore, an object of the present disclosure is to provide a coil component that can increase the fixing strength of the terminal electrodes to the mounting surface. [Means for solving the problem]

[0006] The present disclosure is directed to a coil component including a core having a winding core portion extending in an axial direction and flange portions provided at each axial end of the winding core portion, a wire wound around the winding core portion, and a terminal electrode to which the wire is connected.

[0007] The flange has a mounting surface that faces the mounting board during mounting, and the terminal electrode has a conductive film made of a sintered body of a conductive paste applied to the mounting surface.

[0008] In order to solve the above-mentioned technical problems, the present disclosure is characterized in that the mounting surface is provided with a raised portion whose apex is located inside the edge of the mounting surface in a width direction perpendicular to the axial direction, and the raised portion forms an inclined surface that extends from the apex toward the edge so as to become lower. [Effects of the Invention]

[0009] According to the present disclosure, when the conductive paste to be the conductor film provided on the terminal electrode is applied to the mounting surface by, for example, a dipping method, the ridges provided on the mounting surface allow the thickness of the applied conductive paste to be increased, thereby allowing the conductor film made of the sintered body of the conductive paste to be formed thicker, thereby increasing the adhesive strength of the terminal electrode provided with the conductor film to the mounting surface. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a bottom view showing the appearance of a coil component 1 according to an embodiment of the present disclosure, viewed from the mounting surface side. [Figure 2] 1. (A) is a cross-sectional view taken along line AA in FIG. 1, and (B) is a cross-sectional view taken along line BB in FIG. [Figure 3] 10 is a cross-sectional view illustrating a step of thermocompression bonding a wire 32 to a terminal electrode. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] A coil component 1 according to an embodiment of the present disclosure will be described with reference to FIGS.

[0012] Coil component 1 constitutes, for example, a common mode choke coil and includes core 2 made of, for example, ferrite such as Ni-Zn ferrite, alumina, or a resin containing metal magnetic powder. As shown in Fig. 1, core 2 has a winding core 3 extending in an axial direction AX, and a first flange 5 and a second flange 6 provided at a first end and a second end, respectively, of winding core 3 that are opposite to each other in the axial direction AX. The illustrated winding core 3 has a rectangular cross-sectional shape, but it may also have a polygonal shape such as a hexagon, a circle, an ellipse, or a combination of these.

[0013] Bottom surfaces 7 and 8 of the first flange portion 5 and the second flange portion 6, which face the mounting board (not shown) side when mounted, are shown in FIG.

[0014] On the bottom surface 7 of the first flange 5, two mounting surfaces 9 and 10 facing the mounting board are arranged side by side in the width direction W perpendicular to the axial direction AX. As clearly shown in Figure 2, the mounting surface 9 is located on a convex portion 11 that rises from the bottom surface 7 at a step. The other mounting surface 10 is located on a convex portion 12 that rises from the bottom surface 7 at a step.

[0015] Similarly, two mounting surfaces 13 and 14 facing the mounting board are arranged side by side in the width direction W on the bottom surface 8 of the second flange portion 6. Mounting surface 13 is located on a convex portion 15 that rises from the bottom surface 8 with a step. The other mounting surface 14 is located on a convex portion 16 that rises from the bottom surface 7 with a step.

[0016] By positioning the mounting surfaces 9, 10, 13 and 14 on these convex portions 11, 12, 15 and 16, respectively, the step of applying a conductive paste, which will be described later, can be easily carried out by a dipping method.

[0017] As clearly shown in Figure 2(A), mounting surface 9 is provided with a raised protuberance 17, and mounting surface 10 is provided with a raised protuberance 18. As clearly shown in Figure 2(B), mounting surface 13 is provided with a raised protuberance 19, and mounting surface 14 is provided with a raised protuberance 20. The raised protuberances 17, 18, 19, and 20 have peaks 21, 22, 23, and 24, respectively.

[0018] 1, apexes 21 and 23 are located on imaginary dashed line 25, and apexes 22 and 24 are located on imaginary dashed line 26. That is, apex 21 of raised portion 17 is located inside in the width direction W from the edge of mounting surface 9, apex 22 of raised portion 18 is located inside in the width direction W from the edge of mounting surface 10, apex 21 of raised portion 19 is located inside in the width direction W from the edge of mounting surface 13, and apex 24 of raised portion 20 is located inside in the width direction W from the edge of mounting surface 14.

[0019] Furthermore, the apex 21 of the raised portion 17 has a portion that extends linearly along the imaginary broken line 25, i.e., a portion that extends linearly parallel to the axial direction AX of the winding core 3. The apex 22 of the raised portion 18 has a portion that extends linearly along the imaginary broken line 26, i.e., a portion that extends linearly parallel to the axial direction AX of the winding core 3. The apex 23 of the raised portion 19 has a portion that extends linearly along the imaginary broken line 25, i.e., a portion that extends linearly parallel to the axial direction AX of the winding core 3. The apex 24 of the raised portion 20 has a portion that extends linearly along the imaginary broken line 26, i.e., a portion that extends linearly parallel to the axial direction AX of the winding core 3.

[0020] As shown in Figure 2(A), raised portion 17 forms an inclined surface 27 that extends from its top 21 downward toward the edge of mounting surface 9, and raised portion 18 forms an inclined surface 28 that extends from its top 22 downward toward the edge of mounting surface 10. Similarly, as shown in Figure 2(B), raised portion 19 forms an inclined surface 29 that extends from its top 23 downward toward the edge of mounting surface 13, and raised portion 20 forms an inclined surface 30 that extends from its top 24 downward toward the edge of mounting surface 14.

[0021] The gradient of the inclined surface 27 of the raised portion 17 when viewed in a cross section (not shown) parallel to the axial direction AX of the winding core portion 3 is greater than the gradient of the cross section (shown in FIG. 2(A)) perpendicular to the axial direction AX of the winding core portion 3. Similarly, the gradient of the inclined surface 28 of the raised portion 18 when viewed in a cross section parallel to the axial direction AX of the winding core portion 3 is greater than the gradient of the cross section perpendicular to the axial direction AX of the winding core portion 3; the gradient of the inclined surface 29 of the raised portion 19 when viewed in a cross section parallel to the axial direction AX of the winding core portion 3 is greater than the gradient of the cross section perpendicular to the axial direction AX of the winding core portion 3; and the gradient of the inclined surface 30 of the raised portion 20 when viewed in a cross section parallel to the axial direction AX of the winding core portion 3 is greater than the gradient of the cross section perpendicular to the axial direction AX of the winding core portion 3.

[0022] In addition to the core 2 described above in detail, the coil device 1 includes a first wire 31 and a second wire 32 wound around the winding core portion 3, a first terminal electrode 33 and a third terminal electrode 35 to which the respective ends of the first wire 31 are connected, and a second terminal electrode 34 and a fourth terminal electrode 36 to which the respective ends of the second wire 32 are connected. As shown in Figures 2(A) and 2(B), the terminal electrodes 33 to 36 include conductor films 37 to 40 made of a sintered body of a conductive paste applied to the mounting surfaces 9, 10, 13, and 14, respectively.

[0023] To form the conductor films 37 to 40, a conductive paste application process is performed, for example, by dipping. The conductive paste may contain, for example, glass and silver. As described above, since the mounting surfaces 9, 10, 13, and 14 are located on the convex portions 11, 12, 15, and 16, the conductive paste can be easily applied to the mounting surfaces 9, 10, 13, and 14 by dipping.

[0024] As shown in Figures 2(A) and 2(B), the conductive films 37-40 obtained by firing the conductive paste applied as described above can be made relatively thick due to the presence of the protrusions 17-20. This increases the adhesive strength of the terminal electrodes 33-36 to the mounting surfaces 9, 10, 13, and 14. In this embodiment, the conductive films 37-40 are thicker in the portions around the apexes 21-24 of the protrusions 17-20 than in the portions located on the apexes 21-24 of the protrusions 17-20. This is particularly effective in increasing the resistance of the terminal electrodes 33-36 to external forces in the width direction W.

[0025] If necessary, plating films 41 to 44, each made of, for example, a nickel plating layer and a tin plating layer thereon, are formed on the conductive films 37 to 40. In Figures 2(A) and 2(B), the plating films 41 to 44 are simply shown by thick lines.

[0026] 3 is a diagram illustrating the thermocompression bonding process for connecting wires 31 and 32 to terminal electrodes 33 to 36. Of mounting surfaces 9, 10, 13, and 14 on which terminal electrodes 33 to 36 are provided, mounting surface 10 is illustrated as a representative, and second wire 32 is also illustrated. The thermocompression bonding process is performed substantially in the same way for all of terminal electrodes 33 to 36, so the thermocompression bonding process for terminal electrode 34 provided on mounting surface 10 will be described with reference to FIG. 3. Note that FIG. 3 does not illustrate conductor film 38 provided on mounting surface 10 and terminal electrode 34 including this.

[0027] In the thermocompression bonding process, the heater chip 45 for thermocompression bonding is operated toward the mounting surface 10 with the wire 32 sandwiched between the heater chip 45 and the mounting surface 10. This causes the wire 32 to be thermocompression bonded to the terminal electrode 34 (not shown in FIG. 3).

[0028] In this case, it is preferable that the wire 32 be placed at a position other than the apex 22 on the inclined surface 28 of the raised portion 18 and be connected to the terminal electrode 34 at this position. This is because if the wire 32 is placed so as to overlap the apex 22, stress will be concentrated at the portion of the wire 32 that contacts the apex 22, and the wire 32 may break at the portion where this stress is concentrated.

[0029] Furthermore, it is preferable that the wire 32 is connected to the terminal electrode 34 at a portion of the inclined surface 28 that provides a height difference equal to or less than the diameter of the wire 32 before connection. By doing so, a sufficient load can be applied from the heater tip 45 to the wire 32 during crimping, and crimping quality can be stabilized. The diameter of the wire 32 is set to that "before connection" because the wire 32 becomes flat after connection, and the diameter of the wire 32 varies before and after connection.

[0030] In the embodiment, it is assumed that the diameter of the wire 32 before connection is 10 μm or more and 50 μm or less, and the height difference of the inclined surface 28 is 1 μm or more and 10 μm or less.

[0031] 1, the coil device 1 may further include a top plate 46. The top plate 46 is made of, for example, substantially the same material as the material constituting the core 2, and is fixed to the core 2 by spanning between the surfaces opposite to the bottom surfaces 7 and 8 of the first flange portion 5 and the second flange portion 6.

[0032] In this embodiment, for example, inclined surface 28 extends from top 22 of raised portion 18 in at least two mutually opposite directions in width direction W. The same applies to inclined surfaces 27, 29 to 30. When inclined surfaces 27 to 30 are formed in this manner, it is possible to provide a wider range of preferable crimping locations for wires 31 and 32 to terminal electrodes 33 to 36 compared to when the inclined surfaces extend in only one direction.

[0033] Although the present disclosure has been described above with reference to the illustrated embodiments, various other modifications are possible within the scope of the present disclosure.

[0034] For example, the coil component according to the present disclosure may be a component of a transformer, a balun, or a single coil, in addition to a component of a common mode choke coil as in the illustrated embodiment. Therefore, the number of wires may be changed depending on the function of the coil component, and the number of terminal electrodes provided on each flange may also be changed accordingly.

[0035] Furthermore, in the illustrated embodiment, the peaks 21 to 24 of the raised portions 17 to 20 provided on the mounting surfaces 9, 10, 13 and 14 have linearly extending portions, and these linearly extending portions extend parallel to the axial direction AX of the winding core portion 3, but the linearly extending portions may also extend in a direction that is not parallel to the axial direction AX, for example, in a direction perpendicular to it.

[0036] Furthermore, the raised portion does not have to have a linearly extending portion, and may be provided so as to rise on the mounting surface in a shape such as a cone or a truncated cone.

[0037] In the illustrated embodiment, the peaks 21 to 24 of the protrusions 17 to 20 are at the highest positions on the mounting surfaces 9, 10, 13, and 14, but the highest portions may be located at positions other than the peaks.

[0038] Furthermore, in the illustrated embodiment, the raised portions 17 to 20 have a triangular cross section, and the apexes 21 to 24 are located at the vertices of the triangle, but the vertices of the triangle that form the apexes may be chamfered, or the cross section of the entire raised portion may be a partial circle, a partial ellipse, or a similar shape.

[0039] Furthermore, when configuring a coil component according to the present disclosure, partial substitution or combination of configurations is possible between the different embodiments described in this specification.

[0040] The present disclosure includes the following embodiments.

[0041] <1> a core having a winding core portion extending in an axial direction and flange portions provided at each end of the winding core portion in the axial direction; a wire wound around the winding core; a terminal electrode to which the wire is connected; Equipped with the flange portion has a mounting surface that faces a mounting board during mounting, the terminal electrode includes a conductive film provided on the mounting surface, a protruding portion having an apex located inward from an edge of the mounting surface in a width direction perpendicular to the axial direction, the protruding portion having an inclined surface extending from the apex toward the edge so as to become lower; Coil parts.

[0042] <2> The mounting surface is located on a convex portion of the flange portion that rises with a step from a bottom surface of the flange portion that faces the mounting board during mounting. <1> The coil component according to claim 1.

[0043] <3> the conductive film is thicker at a portion located around the top of the protrusion than at a portion located on the top of the protrusion; <1> or <2> The coil component according to claim 1.

[0044] <4> The top of the raised portion has a linearly extending portion. <1> Or <3> The coil component according to any one of the preceding claims.

[0045] <5> The linearly extending portion extends parallel to the axial direction of the winding core portion. <4> The coil component according to claim 1.

[0046] <6> The inclined surface extends from the top portion in at least two directions opposite to each other in the width direction. <5> The coil component according to claim 1.

[0047] <7> The linearly extending portion extends in a direction perpendicular to the axial direction of the winding core portion. <4> The coil component according to claim 1.

[0048] <8> the slope of the inclined surface of the raised portion when viewed in a cross section parallel to the axial direction of the winding core portion is greater than the slope when viewed in a cross section perpendicular to the axial direction of the winding core portion; <1> Or <7> The coil component according to any one of the preceding claims.

[0049] <9> the wire is connected to the terminal electrode at a position other than the apex of the inclined surface; <1> Or <8> The coil component according to any one of the preceding claims.

[0050] <10> the wire is connected to the terminal electrode at a portion of the inclined surface that provides a height difference equal to or less than the diameter of the wire before connection; <1> Or <9> The coil component according to any one of the preceding claims.

[0051] <11> The diameter of the wire before connection is 10 μm or more and 50 μm or less, and the height difference of the inclined surface is 1 μm or more and 10 μm or less. <10> The coil component according to claim 1. [Explanation of symbols]

[0052] 1 Coil parts 2 cores 3 Winding core 5,6 Tsuba section 7,8 Bottom 9,10,13,14 Mounting surface 11, 12, 15, 16 Convex part 17~20 Ridge 21~24 Top 25,26 Imaginary dashed lines indicating the location of the top 27~30 Slope 31,32 Wire 33~36 Terminal electrode 37~40 Conductor film AX Axial direction W width direction

Claims

1. a core having a winding core portion extending in an axial direction and flange portions provided at each end of the winding core portion in the axial direction; a wire wound around the winding core; a terminal electrode to which the wire is connected; Equipped with the flange portion has a mounting surface that faces a mounting board during mounting, the terminal electrode includes a conductive film provided on the mounting surface, a protruding portion having an apex located inward from an edge of the mounting surface in a width direction perpendicular to the axial direction, the protruding portion having an inclined surface extending from the apex toward the edge so as to become lower; Coil parts.

2. The coil component according to claim 1 , wherein the mounting surface is located on a convex portion of the flange portion that rises in a step from a bottom surface of the flange portion that faces a mounting board when mounted.

3. The coil component according to claim 1 , wherein the conductive film is thicker at a portion located around the top of the protruding portion than at a portion located on the top of the protruding portion.

4. The coil component according to claim 1 , wherein the top of the protrusion has a portion that extends linearly.

5. The coil component according to claim 4 , wherein the linearly extending portion extends parallel to the axial direction of the winding core portion.

6. The coil component according to claim 5 , wherein the inclined surfaces extend from the top portion in at least two directions opposite to each other in the width direction.

7. The coil component according to claim 4 , wherein the linearly extending portion extends in a direction perpendicular to the axial direction of the winding core portion.

8. 2. The coil component according to claim 1, wherein the slope of the inclined surface of the protruding portion when viewed in a cross section parallel to the axial direction of the winding core portion is greater than the slope when viewed in a cross section perpendicular to the axial direction of the winding core portion.

9. The coil component according to claim 1 , wherein the wire is connected to the terminal electrode at a position other than the apex of the inclined surface.

10. The coil component according to claim 1 , wherein the wire is connected to the terminal electrode at a portion of the inclined surface that provides a height difference equal to or less than a diameter of the wire before connection.

11. 11. The coil component according to claim 10, wherein the diameter of the wire before connection is 10 μm or more and 50 μm or less, and the height difference of the inclined surface is 1 μm or more and 10 μm or less.

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