Coil component

Abstract

Provided is a coil component capable of preventing interference of an end portion of a wire with a substrate. A coil component (1) includes a drum core (10), a terminal metal piece (30A) fixed to a flange portion (11), and a wire (W) wound around a winding core portion (13) and connected at one end to the terminal metal piece (30A). The terminal metal piece (30A) includes a connection portion (31) to which the wire (W) is connected, and a mounting portion (32) having elasticity. The connection portion (31) and the mounting portion (32) overlap a surface (S1) of the flange portion (11) when viewed in the z direction. A distance between the surface (S1) and a surface (S3) of the mounting portion (32) is greater than a distance between the surface (S1) and a surface (S2) of the connection portion (31). Thus, the drum core (10) does not have a complicated shape, and a projection is not provided on the terminal metal piece (30A), so interference of the end portion of the wire (W) with the substrate can be prevented. Furthermore, since the mounting portion (32) has elasticity, cracks in solder are less likely to occur.

Description

TECHNICAL FIELD

[0001] The present application relates to a coil component, and particularly to a coil component having a structure in which a terminal metal piece is fixed to a flange portion of a drum core. BACKGROUND

[0002] A coil component having a structure in which a terminal metal piece is fixed to a flange portion of a drum core is disclosed in Patent Literature 1. The terminal metal piece used in Patent Literature 1 has an L-shaped shape, and a wire is wired to a portion that covers a mounting surface of the flange portion. However, when the coil component described in Patent Literature 1 is mounted to a substrate, there is a problem that the end portion of the wire interferes with the substrate.

[0003] On the other hand, in Patent Literature 2, a coil component that prevents interference of the end portion of the wire with the substrate by providing a step to the flange portion is disclosed. However, in order to reliably prevent interference of the end portion of the wire with the substrate, it is necessary to provide a large step to the flange portion, and thus there is a problem that not only the shape of the drum core becomes complicated, but also the capacity of the drum core is reduced.

[0004] In relation to this, the coil component described in Patent Literature 3 prevents interference of the end portion of the wire with the substrate by floating the mounting portion of the terminal metal piece from the flange portion of the drum core.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Laid-Open No. 2018-006438

[0008] Patent Literature 2: Japanese Patent Application Laid-Open No. 2017-199841

[0009] Patent Literature 3: Japanese Patent No. 6065122 SUMMARY

[0010] PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] However, the coil component described in Patent Literature 3 has a problem that not only the mounting area becomes large, but also the wiring portion of the terminal metal piece is easily broken because an external force is easily applied to the wiring portion, since the wiring portion of the terminal metal piece protrudes to the outside in the width direction of the drum core.

[0012] Therefore, an object of the present application is to provide a coil component that does not make the drum core a complicated shape, and that does not need to provide a protruding portion to the terminal metal piece, and that is capable of preventing interference of the end portion of the wire with the substrate.

[0013] MEANS OF SOLVING THE PROBLEMS

[0014] The coil component of the present application is characterized by comprising: a drum core having a winding core portion having a first direction as an axial direction, a first flange portion at one end in the first direction of the winding core portion, and a second flange portion at the other end in the first direction of the winding core portion; a first terminal metal piece and a second terminal metal piece fixed to the first flange portion and the second flange portion, respectively; and a winding wound around the winding core portion, one end of which is connected to the first terminal metal piece and the other end of which is connected to the second terminal metal piece, the first flange portion and the second flange portion having a first surface extending in the first direction and a second direction orthogonal to the first direction, the first terminal metal piece and the second terminal metal piece having a connection portion to which the winding is connected and a mounting portion having elasticity with respect to the drum core, the connection portion and the mounting portion both overlapping the first surface when viewed in a third direction orthogonal to the first direction and the second direction, the connection portion extending in the first direction and the second direction and having a second surface facing in the same direction as the first surface, the mounting portion extending in the first direction and the second direction and having a third surface facing in the same direction as the first surface, the distance between the first surface and the third surface being more separated than the distance between the first surface and the second surface.

[0015] According to the present application, the drum core does not become a complicated shape, and without providing a protruding portion to the terminal metal piece, the end portion of the winding can be prevented from interfering with the substrate. Also, since the mounting portion has elasticity, even if stress is applied to the solder due to the difference in the coefficient of thermal expansion between the drum core and the substrate, the stress can be alleviated by the mounting portion having elasticity, so the solder is less likely to crack.

[0016] In the present application, the portion of the first surface overlapping the connection portion and the portion overlapping the mounting portion when viewed in the third direction can constitute the same plane. By adopting such a structure, the shape of the drum core becomes even simpler, and the capacity of the drum core can be sufficiently ensured.

[0017] In the present application, the mounting portion and the first surface can not be in contact with each other, and a gap can be formed in the third direction. By adopting such a structure, high elasticity can be obtained.

[0018] In the present application, the mounting portion can include a first mounting portion and a second mounting portion, and the connection portion can be located between the first mounting portion and the second mounting portion. By adopting such a structure, the mounting strength can be further improved.

[0019] In the present application, the mounting portion can have a turn-back portion located between the first surface and the third surface, or the mounting portion can have a bent portion bent in a manner that the distance to the first surface is locally closer. By adopting these structures, even if an external force in the third direction is applied after the coil component is mounted to the substrate, the drum core is less likely to be damaged.

[0020] In the present application, the winding can be connected to the second surface of the connection portion, or can be connected to a portion of the connection portion other than the second surface. By adopting the former structure, the connection work of the winding becomes easy, and by adopting the latter structure, the end portion of the winding and the substrate become less likely to interfere with each other.

[0021] Effects of the Invention

[0022] Thus, according to the present application, a coil component can be provided which does not complicate the shape of the drum-shaped core, and in which the end portion of the winding and the substrate are prevented from interfering with each other without providing a protruding portion to the terminal metal piece. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a general perspective view showing the appearance of a coil component 1 according to a first embodiment of the present application.

[0024] Figure 2 is a general exploded perspective view of the coil component 1.

[0025] Figure 3 is a view for explaining the shape of a terminal metal piece 30A, in which (a) is a general perspective view, (b) is a yz front view, and (c) is an xz side view.

[0026] Figure 4 is a general perspective view showing a state in which the coil component 1 is mounted to a substrate 6.

[0027] Figure 5 is a general perspective view showing the appearance of a coil component 2 according to a second embodiment of the present application.

[0028] Figure 6 is a view for explaining the shape of a terminal metal piece 50A, in which (a) is a general perspective view, (b) is a yz front view, and (c) is an xz side view.

[0029] Figure 7 is a general perspective view showing a state in which the coil component 2 is mounted to the substrate 6.

[0030] Figure 8 is a general perspective view showing the appearance of a coil component 3 according to a third embodiment of the present application.

[0031] Figure 9 is a partial general perspective view for explaining the shape of a terminal metal piece 30B.

[0032] Figure 10 is a general perspective view showing the appearance of a coil component 4 according to a fourth embodiment of the present application.

[0033] Figure 11This is a partial, approximate three-dimensional view used to illustrate the shape of the terminal metal part 50B.

[0034] Figure 12 This is a partial side view showing the structure of the main part of the coil component 5 according to the fifth embodiment of the present invention. Detailed Implementation

[0035] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0036] <First Embodiment>

[0037] Figure 1 This is a general perspective view showing the appearance of the coil component 1 according to the first embodiment of the present invention. Furthermore, Figure 2 This is a roughly exploded perspective view of coil component 1.

[0038] like Figure 1 and Figure 2 As shown, the coil component 1 of the first embodiment includes: a drum-shaped core 10; a plate-shaped core 20; a terminal metal member 30A fixed to the first flange portion 11 of the drum-shaped core 10; a terminal metal member 40A fixed to the second flange portion 12 of the drum-shaped core 10; and a winding wire W wound on the core portion 13 of the drum-shaped core 10. One end of the winding wire W is connected to the terminal metal member 30A, and the other end of the winding wire W is connected to the terminal metal member 40A. The core portion 13 of the drum-shaped core 10 has a flange portion 11 at one end and a flange portion 12 at the other end in the axial direction. The drum-shaped core 10 is made of a magnetic material with high permeability, such as Ni-Zn ferrite. The plate-shaped core 20 is also made of a magnetic material with high permeability, such as Ni-Zn ferrite, and is fixed to the flange portions 11 and 12 by using an adhesive or the like to form a closed annular magnetic circuit. In this invention, the use of plate core 20 is not necessary, but by using plate core 20, the inductance can be significantly improved.

[0039] Figure 3 This is a diagram illustrating the shape of terminal metal part 30A, where (a) is a general perspective view, (b) is a yz front view, and (c) is an xz side view. Although not shown, terminal metal part 40A also has the same shape.

[0040] Terminal metal part 30A is a metal component made of a good conductor such as copper, such as... Figure 3 As shown, it has a wiring portion 31, a mounting portion 32, and a connecting portion 33 that connects the wiring portion 31 and the mounting portion 32. The terminal metal part 40A also has a wiring portion 41, a mounting portion 42, and a connecting portion 43. The wiring portion 31 is the portion that connects to the end of the winding W, and the mounting portion 32 is the portion that connects to the pad pattern when the coil component 1 is mounted on the substrate. The connecting portion 33 is a plate-like body with the yz plane as its main surface, such as...Figure 1 As shown, the flange portion 11, which forms the yz plane, is covered. The wiring portion 31 and the mounting portion 32 are the ends of the connecting portion 33 that are bent along the x-direction, and each has surfaces S2 and S3 forming the xy plane. Surfaces S2 and S3 are separated by a height H in the z-direction. Surface S2 is the surface with the end of the wire W connected, and surface S3 is the surface opposite to the pad pattern of the substrate, both facing the same direction as surface S1 of the flange portion 11.

[0041] The terminal metal part 30A can be fixed relative to the flange portion 11 by applying an adhesive or the like to the surface S1 of the flange portion 11 constituting the xy plane. When the terminal metal part 30A is fixed to the flange portion 11, the wiring portion 31 and the mounting portion 32 overlap with the flange portion 11 when viewed from the z direction, and the connecting portion 33 overlaps with the flange portion 11 when viewed from the x direction. The width of the terminal metal part 30A in the y direction is narrower than the width of the flange portion 11 in the y direction, so the terminal metal part 30A does not have a portion protruding from the flange portion 11 in the y direction. Moreover, the wiring portion 31 is directly fixed to the surface S1 of the flange portion 11 by an adhesive or the like, while the mounting portion 32 does not contact the surface S1 of the flange portion 11, and a gap in the z direction is formed between the mounting portion 32 and the surface S1 of the flange portion 11. As a result, the mounting portion 32 is elastic relative to the drum-shaped core 10.

[0042] Figure 4 This is a general perspective view showing the state in which the coil component 1 of this embodiment is mounted on the substrate 6.

[0043] like Figure 4 As shown, when the coil component 1 of this embodiment is mounted on the substrate 6, the pad pattern P1 formed on the surface of the substrate 6 faces the surface S3 of the mounting portion 32 of the terminal metal member 30A, and the pad pattern P2 formed on the surface of the substrate 6 faces the surface S3 of the mounting portion 42 of the terminal metal member 40A. The pad patterns P1 and P2 are electrically and mechanically connected to the mounting portions 32 and 42 by solder 7. Here, the distance in the z-direction between the surface S1 of the flange portions 11 and 12 and the surface S3 of the mounting portions 32 and 42 is separated by a height H compared to the distance in the z-direction between the surface S1 of the flange portions 11 and 12 and the surface S2 of the wiring portions 31 and 41. Therefore, when the coil component 1 is mounted on the substrate 6, a gap corresponding to the height H is formed between the substrate 6 and the surface S2 of the wiring portions 31 and 41. Therefore, the end of the winding W connected to the surface S2 of the wiring portions 31 and 41 will not interfere with the substrate 6.

[0044] Further, since the mounting portions 32, 42 are not directly fixed to the surface S1 of the flange portions 11, 12, and thus have elasticity, even after the coil component 1 is mounted to the substrate 6, stress applied to the solder 7 is mitigated by the elasticity of the mounting portions 32, 42 even if the temperature changes. Therefore, the mounting reliability of the coil component 1 can be improved. In addition, since the surface S1 of the flange portions 11, 12 is not provided with a step but is a flat surface, the portion overlapping the terminal portions 31, 41 and the portion overlapping the mounting portions 32, 42 form the same plane when viewed in the z direction, and thus the shape of the drum core 10 becomes simpler, and the capacity of the drum core 10 can also be sufficiently ensured. Further, since it is not necessary to provide a pad pattern in the portion overlapping the terminal portions 31, 41, the parasitic capacitance component due to the pad pattern is also reduced.

[0045] <2nd Embodiment>

[0046] Figure 5 is a general perspective view showing the appearance of the coil component 2 of the 2nd embodiment of the present application.

[0047] As shown in Figure 5 , the coil component 2 of the 2nd embodiment differs from the coil component 1 of the 1st embodiment in that terminal metal pieces 50A, 60A are used instead of the terminal metal pieces 30A, 40A. The other basic structure is the same as that of the coil component 1 of the 1st embodiment, and thus the same symbols are given to the same elements, and the repeated explanation is omitted.

[0048] Figure 6 is a view for explaining the shape of the terminal metal piece 50A, in which (a) is a general perspective view, (b) is a yz front view, and (c) is an xz side view. Although not shown, the terminal metal piece 60A also has the same shape.

[0049] As shown in Figure 6 , the terminal metal piece 50A has a terminal portion 51, mounting portions 52, 53, and a connection portion 54 connecting the terminal portion 51 and the mounting portions 52, 53. The terminal portion 51 is located between the mounting portion 52 and the mounting portion 53. The terminal metal piece 60A also has a terminal portion 61, mounting portions 62, 63, and a connection portion 64 connecting the terminal portion 61 and the mounting portions 62, 63. The terminal portion 51 is a portion to which the end of the wire W is wired, and the mounting portions 52, 53 are portions to be connected to a pad pattern when the coil component 2 is mounted to a substrate. The connection portion 54 is a plate-like body having the yz plane as a main surface, and Figure 5The outer side of the flange portion 11 constituting the yz plane is covered by the surface S1. The terminal metal piece 50A has the surface S2 and the surface S3 which are surfaces constituting the xy plane. The surface S2 is separated from the surface S3 by the height H in the z direction. The surface S2 is a surface to which the end portion of the wire W is connected, and the surface S3 is a surface which opposes the pad pattern of the substrate.

[0050] The terminal metal piece 50A is fixed to the flange portion 11 by an adhesive or the like applied to the surface S1 of the flange portion 11 constituting the xy plane. When the terminal metal piece 50A is fixed to the flange portion 11, the connecting portion 54 overlaps the flange portion 11 when viewed in the x direction, and the terminal metal piece 50A does not have a portion which protrudes from the flange portion 11 in the y direction. Moreover, the connecting portion 54 is fixed to the surface S1 of the flange portion 11 by an adhesive or the like, and the connecting portion 54 is separated from the surface S1 of the flange portion 11 in the z direction. Thus, the connecting portion 54 has elasticity with respect to the drum core 10.

[0051] Figure 7 is a perspective view showing a state in which the coil component 2 of the present embodiment is mounted to the substrate 6.

[0052] As shown in Figure 7 In the case where the coil component 2 of the present embodiment is mounted to the substrate 6, the coil component 2 is mounted in such a manner that the pad pattern PI formed on the surface of the substrate 6 opposes the surface S3 of the mounting portions 52, 53 of the terminal metal piece 50A, and the pad pattern P2 formed on the surface of the substrate 6 opposes the surface S3 of the mounting portions 62, 63 of the terminal metal piece 60A. The pad patterns PI, P2 and the mounting portions 52, 53, 62, 63 are electrically and mechanically connected by the solder 7. The pad pattern PI can be divided into a portion opposing the mounting portion 52 and a portion opposing the mounting portion 53. Similarly, the pad pattern P2 can be divided into a portion opposing the mounting portion 62 and a portion opposing the mounting portion 63. As in the first embodiment, the distance between the surface S1 of the flange portions 11, 12 and the surface S3 of the mounting portions 52, 53, 62, 63 in the z direction is separated by the height H from the distance between the surface S1 of the flange portions 11, 12 and the surface S2 of the connecting portions 51, 61 in the z direction, and thus a gap corresponding to the height H is formed between the substrate 6 and the surface S2 of the connecting portions 51, 61 when the coil component 2 is mounted to the substrate 6. Therefore, the end portion of the wire W connected to the surface S2 of the connecting portions 51, 61 does not interfere with the substrate 6.

[0053] And, since the mounting portions 52, 53, 62, 63 are not directly fixed to the surfaces S1 of the flange portions 11, 12, and thus have elasticity, even after the coil component 2 is mounted to the substrate 6, stress applied to the solder 7 is mitigated by the elasticity of the mounting portions 52, 53, 62, 63 even if the temperature changes. Therefore, the mounting reliability of the coil component 2 can be improved. Further, since two mounting portions 52, 53 are connected to the pad pattern PI, and two mounting portions 62, 63 are connected to the pad pattern P2, a higher mounting strength than the first embodiment can be obtained.

[0054] <3rd Embodiment>

[0055] Figure 8 is a general perspective view showing the appearance of the coil component 3 of the third embodiment of the present application.

[0056] As shown in Figure 8 , the coil component 3 of the third embodiment uses the terminal metal pieces 30B, 40B instead of the terminal metal pieces 30A, 40A, which is different from the coil component 1 of the first embodiment. The other basic structure is the same as that of the coil component 1 of the first embodiment, so the same reference numerals are given to the same elements, and the repeated explanation is omitted.

[0057] Figure 9 is a partial general perspective view for explaining the shape of the terminal metal piece 30B.

[0058] As shown in Figure 9 , the terminal metal piece 30B has a turn-back portion 34 between the surfaces S1 and S3 at the mounting portion 32, which is different from the above-described terminal metal piece 30A. The turn-back portion 34 is a portion in which the leading end of the mounting portion 32 is bent inward by 180°, and in the present embodiment, does not contact the surface S1 of the flange portion 11. The terminal metal piece 40B also has the same turn-back portion 44.

[0059] Thus, the coil component 3 of the present embodiment, since the terminal metal pieces 30B, 40B have the turn-back portions 34, 44, when an external force in the z direction is applied to the coil component 3 after being mounted to the substrate 6, by the turn-back portions 34, 44 contacting the surfaces S1 of the flange portions 11, 12, displacement of the drum core 10 in the z direction can be suppressed. Thus, breakage due to the drum core 10 being greatly displaced in the z direction by an external force is less likely to occur.

[0060] Further, in the present embodiment, although the turn-back portions 34, 44 of the terminal metal pieces 30B, 40B do not contact the surfaces S1 of the flange portions 11, 12, since the mounting portions 32, 42 themselves having the turn-back portions 34, 44 have elasticity, it is also possible to be configured so that both contact.

[0061] <4th Embodiment>

[0062] Figure 10 is a general perspective view showing the appearance of the coil component 4 of the 4th embodiment of the present application.

[0063] As shown in Figure 10 , the coil component 4 of the 4th embodiment uses the terminal metal pieces 50B, 60B instead of the terminal metal pieces 50A, 60A, which is different from the coil component 2 of the 2nd embodiment. The other basic structure is the same as that of the coil component 2 of the 2nd embodiment, the same symbols are given to the same elements, and the repeated explanation is omitted.

[0064] Figure 11 is a partial general perspective view for explaining the shape of the terminal metal piece 50B.

[0065] As shown in Figure 11 , the terminal metal piece 50B has the bent portions 55, 56 which are bent toward the surface S1 of the flange portion 11 at a part of the mounting portions 52, 53, which is different from the above-described terminal metal piece 50A. Thereby, the mounting portions 52, 53 are locally made close in distance to the surface S1 of the flange portion 11 at the bent portions 55, 56. In the present embodiment, the bent portions 55, 56 do not contact the surface S1 of the flange portion 11. The terminal metal piece 60B also has the same bent portions 65, 66.

[0066] Thus, the coil component 4 of the present embodiment, since the terminal metal pieces 50B, 60B have the bent portions 55, 56, 65, 66, when an external force in the z direction is applied to the coil component 4 after being mounted to the substrate 6, by the bent portions 55, 56, 65, 66 contacting the surface S1 of the flange portions 11, 12, the displacement of the drum core 10 in the z direction can be suppressed. Thereby, the breakage due to the drum core 10 being largely displaced in the z direction by the external force is less likely to occur.

[0067] Further, in the present embodiment, although the bent portions 55, 56, 65, 66 of the terminal metal pieces 50B, 60B do not contact the surface S1 of the flange portions 11, 12, since the mounting portions 52, 53, 62, 63 themselves having the bent portions 55, 56, 65, 66 have elasticity, it can also be configured so that both of them contact.

[0068] <5th Embodiment>

[0069] Figure 12 is a partial side view showing the structure of the main part of the coil component 5 of the 5th embodiment of the present application.

[0070] As shown in Figure 12As shown, in the coil component 5 of the fifth embodiment, one end of the wire W is not formed on the surface S2 of the terminal portion 31, but is connected to the surface S4 of the terminal portion 31 by the conductive member 70 such as solder. Although not shown, the other end of the wire W is also similarly connected. Since the other basic structure is the same as that of the coil component 1 of the first embodiment, the same reference numerals are given to the same elements, and the repeated explanation is omitted. The surface S4 of the terminal portion 31 is an xy plane opposite to the surface S1 of the flange portion 11, and the conductive member 70 is provided between the surface S1 and the surface S4. Further, the end portion of the wire W is connected to the conductive member 70. By adopting such a structure, in the case where the coil component 5 is mounted to the substrate 6, interference of the wire W with the substrate 6 is less likely to occur.

[0071] The preferred embodiments of the present application have been described above, but the present application is not limited to the above-described embodiments, and various changes can be made within the scope of the gist of the present application, and the modes obtained by making these changes are of course included in the scope of the present application.

[0072] Symbol explanation

[0073] 1 to 5 Coil component

[0074] 6 Substrate

[0075] 7 Solder

[0076] 10 Drum core

[0077] 11, 12 Flange portion

[0078] 13 Winding core portion

[0079] 20 Plate core

[0080] 30A, 30B, 40A, 40B, 50A, 50B, 60A, 60B Terminal metal piece

[0081] 31, 41, 51, 61 Terminal portion

[0082] 32, 42, 52, 53, 62, 63 Mounting portion

[0083] 33, 43, 54, 64 Connection portion

[0084] 34, 44 Turnback portion

[0085] 55, 56, 65, 66 Bending portion

[0086] 70 Conductive member

[0087] P1, P2 Pad pattern

[0088] S1 to S4 Surface

[0089] W winding

Claims

1. A coil component characterized by comprising: a drum core having a winding core portion with a first direction as an axial direction, a first flange portion at one end in the first direction of the winding core portion, and a second flange portion at the other end in the first direction of the winding core portion; a first terminal metal piece and a second terminal metal piece fixed to the first flange portion and the second flange portion, respectively; and a winding wound around the winding core portion, one end of which is connected to the first terminal metal piece and the other end of which is connected to the second terminal metal piece, wherein the first flange portion and the second flange portion have a first surface extending in the first direction and a second direction orthogonal to the first direction, wherein the first terminal metal piece and the second terminal metal piece have a connection portion to which the winding is connected, and a mounting portion which is elastic with respect to the drum core, wherein the connection portion and the mounting portion overlap the first surface when viewed in a third direction orthogonal to the first direction and the second direction, wherein the connection portion extends in the first direction and the second direction and has a second surface which faces in the same direction as the first surface, wherein the mounting portion extends in the first direction and the second direction and has a third surface which faces in the same direction as the first surface, wherein the distance between the first surface and the third surface is more separated than the distance between the first surface and the second surface, wherein the portion of the first surface which overlaps the connection portion and the portion of the first surface which overlaps the mounting portion, when viewed in the third direction, constitute the same plane, wherein the mounting portion and the first surface do not contact each other and a gap is formed in the third direction, wherein the mounting portion includes a first mounting portion and a second mounting portion, and wherein the connection portion is positioned between the first mounting portion and the second mounting portion in such a manner that the connection portion is pinched by the first mounting portion and the second mounting portion in the second direction when viewed in the third direction.

2. The coil component according to claim 1, characterized in that the mounting portion has a turn-back portion between the first surface and the third surface.

3. The coil component according to claim 1, characterized in that the mounting portion has a bent portion which is bent in such a manner that the distance to the first surface is locally closer.

4. The coil component according to any one of claims 1 to 3, characterized in that the winding is connected to the second surface of the connection portion.

5. The coil component according to any one of claims 1 to 3, characterized in that the winding is connected to a portion of the connection portion other than the second surface. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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