Coil component

Abstract

The present invention relates to a coil component in which a terminal electrode and a terminal end of a wire are connected by thermocompression bonding at a bottom surface of a flange portion, and the following effects are obtained as a result of thermocompression bonding being appropriately performed without being excessively insufficient, that is, a stable fixing force is obtained for the connection state between the terminal electrode and the terminal end of the wire, and problems caused by the terminal end of the wire protruding from the terminal electrode are less likely to occur. A terminal end (21a) of a wire (21) is in a state of being at least partially disposed inside a terminal electrode (17) and extending along a main surface (25) of the terminal electrode, and has a top surface (33) located at a side opposite to the bottom surface (23) of a flange portion (13) from the main surface. A solder tail surface (37) that rises from the main surface toward the top surface and forms a concave curved surface is formed on an outer surface of the terminal electrode. The main surface is realized by a parent solder material layer (31) composed of tin or a tin alloy that constitutes an outermost layer of the terminal electrode.

Description

[0001] This application is a divisional application of application number 2021 1 1486 672.4, filed on December 7, 2021, entitled "Coil Component". Technical Field

[0002] The present invention relates to a coil component with a wire wound in the core portion, and particularly to a connection structure between the wire and the terminal electrode. Background Technology

[0003] As a technology of interest in this invention, for example, there is the technology described in Japanese Patent Application Publication No. 10-312922 (Patent Document 1). Patent Document 1 describes a coil component having a structure in which the wire and terminal electrodes are connected by thermoforming. Figure 7 It is cited from Patent Document 1, and it is equivalent to the content in Patent Document 1. Figure 1 (C). In Figure 7 The cross-section shows a portion of a flange 2 of the core 1.

[0004] like Figure 7 As shown, a terminal electrode 4 is provided on the bottom surface 3 of the flange portion 2 facing the mounting surface. The terminal electrode 4 includes, for example, a highly conductive material layer 5 made of silver or a silver alloy, a solder-resistant material layer 6 made of nickel or the like above the highly conductive material layer 5 that exhibits low solder wetting and spreading during mounting, and a solder-resistant material layer 7 made of tin or a tin alloy above the solder-resistant material layer 6 that exhibits good solder wetting and spreading during mounting. Figure 7 In the middle, the terminal 8 of the wire wound on the winding core (not shown) is connected to the terminal electrode 4 by heat pressing.

[0005] In the aforementioned hot-pressing process, the wire terminal 8 is positioned on the terminal electrode 4. In this state, the wire terminal 8 is pressed into the terminal electrode 4 using a welding head (not shown). As a result, the wire terminal 8 is compressed into a flattened cross-section and embedded to a position where it forms approximately the same surface as the surface of the master solder layer 7. In this way, a highly reliable joint can be obtained between the wire terminal 8 and the terminal electrode 4.

[0006] Patent Document 1: Japanese Patent Application Publication No. 10-312922

[0007] It is known that the miniaturization of the core, the diversification of wire diameter (thicker wire, thinner wire), and the high heat resistance of the insulation film of the wire are all developments. In addition, with the change of requirements for specifications such as the high load of reliability testing, even if the wire terminal 8 is connected to the solder material layer 7 of the terminal electrode 4 by heat pressing as described in the above-mentioned Patent Document 1, there are still cases where the desired connection state cannot be obtained.

[0008] For example, in the hot-pressing process, when the wire end 8 is pressed to a position where it is approximately on the same surface as the mother solder layer 7, sometimes the flange portion 2 of the core 1, the core portion, or the wire end 8 cannot withstand the hot pressing and is damaged, or as... Figure 8 As shown, sometimes the solder layer 7 scatters around the periphery of the wire terminal 8. This scattering not only leads to the deterioration of the terminal electrode 4, resulting in partial loss of function, but also causes poor bonding between the wire terminal 8 and the terminal electrode 4. Furthermore, it is considered that the scattering of the solder layer 7 is caused by the melting of the wire's insulation film, which pushes away the molten solder layer 7 around the wire terminal 8.

[0009] Furthermore, it is known that when the damage is minor or the degree of spalling of the solder layer 7 is low, it will not be a problem under previous reliability test conditions, but under high-load reliability test conditions, it will become the cause of damage to the core 1, wire breakage, and peeling of the terminal electrode 4.

[0010] On the other hand, if the hot pressing conditions are relaxed to avoid excessive hot pressing as described above, then... Figure 9 As shown, the bonding area between the wire terminal 8 and the solder layer 7 cannot be fully obtained, resulting in insufficient fixing force between the wire terminal 8 and the terminal electrode 4. Furthermore, if the hot-pressing conditions are relaxed, even after hot-pressing, the bonding force remains insufficient. Figure 9 As shown by the dashed line, sometimes there are localized areas of residual insulating film 9 at the wire terminal 8. This can also be a cause of reduced fixing force between the wire terminal 8 and the terminal electrode 4.

[0011] Furthermore, sometimes due to insufficient heat bonding, the wire terminal 8 protrudes significantly from the solder paste layer 7. In this case, during installation, the bottom surface 3 of the flange 2, where the terminal electrode 4 is located, faces the mounting surface. At this bottom surface 3, the wire terminal 8 is heat-bonded into the coil component constructed with the terminal electrode 4. The protruding wire terminal 8 hinders the wetting and spreading of the solder paste used for installation. In addition, the protrusion of the wire terminal 8 at the bottom surface 3 of the flange 2 also leads to instability in the posture of the coil component before it is fixed to the mounting substrate. In particular, the problem of instability in the posture of the coil component during installation is more likely to occur with the reduction of coil component size, the reduction of mounting area, and the reduction of terminal electrode area.

[0012] Thus, especially in coil components where the terminal electrode 4 and the wire terminal 8 are heat-pressed together at the bottom surface 3 of the flange portion 2, the difficulty of heat pressing increases.

[0013] Furthermore, coil components typically have at least two terminal electrodes, each connected to a terminal of the wire. Therefore, ideally, the aforementioned problems would be solved in the connection between all terminal electrodes and the wire terminals. However, compared to situations where problems cannot be solved at all, improvements can still be implemented that facilitate problem-solving, for example, by solving the problem only in the connection between one terminal electrode and one terminal of the wire. Summary of the Invention

[0014] Therefore, the object of the present invention is that, in a coil component where the terminal electrode and the end of the wire are connected by heat-pressing at the bottom surface of the flange, as a result of implementing the heat-pressing under appropriate conditions without being too insufficient, not only is it less likely to cause damage to the core, wire breakage, or peeling of the terminal electrode, but also a stable fixing force can be obtained for the connection state between the terminal electrode and the end of the wire, and problems caused by the end of the wire protruding from the terminal electrode are less likely to occur.

[0015] This invention relates to a coil component, which comprises:

[0016] The core has a core portion extending along the axial direction and a first flange portion and a second flange portion respectively provided at a first end and a second end opposite to each other in the axial direction of the core portion;

[0017] The first terminal electrode is disposed on the first flange portion;

[0018] The second terminal electrode is disposed on the second flange portion; and

[0019] The first wire is wound around its core.

[0020] The first wire has a first terminal connected to a first terminal electrode and a second terminal connected to a second terminal electrode.

[0021] The first flange portion has a first bottom surface facing the mounting surface side, and the second flange portion has a second bottom surface facing the mounting surface side.

[0022] The first terminal electrode has a first main surface extending along a first bottom surface, and the second terminal electrode has a second main surface extending along a second bottom surface.

[0023] The first terminal is at least partially disposed within the first terminal electrode and extends along the first main surface, and has a first top surface located on the side opposite to the first bottom surface to the first main surface.

[0024] To solve the above-mentioned technical problems, the coil component of the present invention is characterized in that the outer surface of the first terminal electrode has a first solder foot surface that protrudes from the first main surface toward the first top surface and forms a concave curved surface.

[0025] According to the present invention, a first solder foot surface is provided on the outer surface of the first terminal electrode disposed on the bottom surface of the flange portion, which protrudes from the first main surface of the first terminal electrode toward the first top surface of the first wire and forms a concave curved surface. Therefore, it can be confirmed that the heat-pressing between the first terminal electrode and the first terminal of the first wire is not insufficiently performed under appropriate conditions. As a result, even under high-load environments, damage to the core, wire breakage, and peeling of the first terminal electrode are less likely to occur.

[0026] In addition, the formation of the first solder joint surface at the first terminal electrode can increase the bonding area between the first terminal of the first wire and the first terminal electrode, and can alleviate stress concentration in the first terminal electrode, thus improving the fixing force between the connected first terminal electrode and the first terminal of the first wire.

[0027] In addition, the formation of the first solder face in the first terminal electrode can mitigate the sharpness of the first terminal of the first wire protruding from the first terminal electrode. Therefore, even at the first bottom surface of the first flange, the coil component with the first terminal of the first wire connected to the first terminal electrode can easily prevent the wetting and spreading of the solder paste used for mounting. Furthermore, it is less likely to cause instability in the posture of the coil component before it is fixed to the mounting substrate. Attached Figure Description

[0028] Figure 1 This is a bottom view of the coil component 11 according to the first embodiment of the present invention.

[0029] Figure 2 yes Figure 1 The right view of the coil component 11 shown.

[0030] Figure 3 This is a schematic enlargement indicating along Figure 1 A diagram of the characteristic portion of the cross section of line SS.

[0031] Figure 4 This is for explaining the second embodiment of the present invention. Figure 3 The corresponding diagram.

[0032] Figure 5 This is for describing the third embodiment of the present invention. Figure 3 The corresponding diagram.

[0033] Figure 6 This is for describing the fourth embodiment of the present invention. Figure 3 The corresponding figures (A) and (B) show the connection between the different terminal electrodes 17 and 18 and the wire 21.

[0034] Figure 7 It is cited from Patent Document 1, and is equivalent to the content in Patent Document 1. Figure 1 (C) represents a portion of a flange 2 of the core 1.

[0035] Figure 8 This is a cross-sectional view used to illustrate the problem to be solved by the present invention, showing the state resulting from excessive heat-pressing conditions when the terminal electrode 4 is connected to the terminal 8 of the wire.

[0036] Figure 9 This is a cross-sectional view used to explain the problem to be solved by the present invention, showing the state resulting from insufficient thermoforming conditions when the terminal electrode 4 is connected to the terminal 8 of the wire.

[0037] Explanation of reference numerals in the attached figures:

[0038] 11…coil component; 12…core portion; 13, 14…flange portion; 15…core body; 17~20…terminal electrodes; 21, 22…wire; 21a, 21b, 22a, 22b…terminals; 23, 24…bottom surface; 25~28…main surface; 29…good conductive material layer; 30…solder-resistant material layer; 31…bonding material layer; 33~36…top surface; 37~40…solder foot surface; AX…axial direction; W…width dimension of solder foot surface; H…height dimension of solder foot surface; C…center of the first terminal in a direction orthogonal to the first bottom surface. Detailed Implementation

[0039] Reference Figure 1 and Figure 2 The coil component 11, for example, constitutes a common-mode choke coil and includes a core 15, which has a core portion 12 extending along the axial direction AX; and a first flange portion 13 and a second flange portion 14 respectively provided at a first end and a second end opposite to each other in the axial direction AX of the core portion 12. The core 15 is made of a non-conductive material such as alumina or ferrite.

[0040] The coil component 11 also includes a top plate 16 that connects the pair of flanges 13 and 14 of the core 15. If both the core 15 and the top plate 16 are made of magnetic material, the top plate 16 can cooperate with the core 15 to form a closed magnetic circuit around the magnetic flux.

[0041] A first terminal electrode 17 and a third terminal electrode 19 are provided on the first flange portion 13. A second terminal electrode 18 and a fourth terminal electrode 20 are provided on the second flange portion 14.

[0042] The first wire 21 and the second wire 22 are wound around the core portion 12 in the same direction. The first wire 21 has a first terminal 21a connected to the first terminal electrode 17 and a second terminal 21b connected to the second terminal electrode 18. The second wire 22 has a third terminal 22a connected to the third terminal electrode 19 and a fourth terminal 22b connected to the fourth terminal electrode 20.

[0043] The first flange portion 13 has a first bottom surface 23 facing the mounting surface side. The second flange portion 14 has a second bottom surface 24 facing the mounting surface side.

[0044] A first terminal electrode 17 is disposed on a first bottom surface 23 and is configured to extend from the first bottom surface 23 to portions of each of a plurality of adjacent surfaces. A second terminal electrode 18 is disposed on a second bottom surface 24 and is configured to extend from the second bottom surface 24 to portions of each of a plurality of adjacent surfaces. The first terminal electrode 17 has a first main surface 25 extending along the first bottom surface 23. The second terminal electrode 18 has a second main surface 26 extending along the second bottom surface 24.

[0045] The third terminal electrode 19 is disposed on the first bottom surface 23 at a predetermined interval relative to the first terminal electrode 17, and is configured to extend from the first bottom surface 23 to portions of each of a plurality of adjacent surfaces. The fourth terminal electrode 20 is disposed on the second bottom surface 24 at a predetermined interval relative to the second terminal electrode 18, and is configured to extend from the second bottom surface 24 to portions of each of a plurality of adjacent surfaces. The third terminal electrode 19 has a third main surface 27 extending along the first bottom surface 23. The fourth terminal electrode 20 has a fourth main surface 28 extending along the second bottom surface 24.

[0046] exist Figure 3 The enlarged view shows the cross-sectional structure of the portion of the first terminal electrode 17 located on the first bottom surface 23. Furthermore, the cross-sectional structures of the second terminal electrode 18, the third terminal electrode 19, and the fourth terminal electrode 20 are substantially the same as those of the first terminal electrode 17. Therefore, the cross-sectional structure of the first terminal electrode 17 will be described in detail below, while the descriptions of the cross-sectional structures of the second terminal electrode 18, the third terminal electrode 19, and the fourth terminal electrode 20 will be omitted.

[0047] The first terminal electrode 17 includes: a highly conductive material layer 29, such as silver, copper, or their alloys, located on the first bottom surface 23 of the first flange portion 13; a solder-resistant material layer 30, such as nickel, above the highly conductive material layer 29; and a solder-resistant material layer 31, such as tin or a tin alloy, above the solder-resistant material layer 30. The first main surface 25 of the aforementioned first terminal electrode 17 is formed by the outermost solder-resistant material layer 31. Typically, the highly conductive material layer 29 is formed by sintering a conductive paste, but it can also be formed by sputtering. In addition, the solder-resistant material layer 30 and the solder-resistant material layer 31 are typically formed by plating.

[0048] exist Figure 3 The diagram shows the state in which the first terminal 21a of the first wire 21 is connected to the first terminal electrode 17. For this connection, a thermoforming process is applied. In the thermoforming process, the first terminal 21a of the first wire 21 is positioned on the first terminal electrode 17, and in this state, the first terminal 21a of the first wire 21 is pressed toward the first terminal electrode 17 using a soldering head (not shown). As a result, the first terminal 21a of the first wire 21 is compressed into a flattened cross-section, and it is at least partially embedded in the first terminal electrode 17, more specifically, embedded in the solder base layer 31, and closely attached to the flat solder-resistant material layer 30. Thus, the first terminal 21a of the first wire 21 is connected to the first terminal electrode 17.

[0049] The first wire 21 includes, for example, a copper core wire with a circular cross-section and an insulating film made of a resin such as polyurethane or polyimide covering its periphery. Preferably, the first wire 21 has a core wire diameter of 20 μm to 150 μm. In this case, the result of the aforementioned heat-pressing is that the first terminal 21a of the first wire 21, which is compressed into a flat cross-section, preferably shows the width dimension of the cross-section (in...). Figure 3 The dimensions measured in the left-right direction are 24 μm to 350 μm, that is, an increase rate of +20% to +133%. On the other hand, the dimensions in the height direction of the cross-section are shown. Figure 3 The dimensions measured in the vertical direction are 4μm to 120μm, which is a reduction rate of -80% to -20%.

[0050] To give an example, the first wire 21 uses a wire with a core diameter of 30 μm. In this case, the result of heat compression is that the first terminal 21a of the first wire 21, which is compressed into a flat cross-section, shows that the width dimension of the cross-section becomes 40 μm, that is, an increase rate of +33%, while on the other hand, the height dimension of the cross-section becomes 15 μm, that is, a decrease rate of -50%.

[0051] The second wire 22 is also practically the same as the first wire 21.

[0052] As a result of the aforementioned hot-pressing, the first terminal 21a of the first wire 21 is at least partially disposed within the first terminal electrode 17, and more specifically, within the solder material layer 31. The first terminal 21a of the first wire 21 extends along the first main surface 25 of the first terminal electrode 17. At this time, the top surface 33 of the first terminal 21a is located on the opposite side from the first bottom surface 23 of the first flange portion 13 compared to the first main surface 25 of the first terminal electrode 17. More importantly, a solder foot surface 37 is provided on the outer surface of the first terminal electrode 17, which protrudes from the first main surface 25 toward the top surface 33 of the first terminal 21a of the first wire 21 and forms a concave curved surface.

[0053] As described above, if the solder pad 37 is provided, it can be confirmed that the heat-pressing connection between the first terminal electrode 17 and the first terminal 21a of the first wire 21 will not be insufficiently implemented under appropriate conditions. This makes it less likely that damage to the core 15, wire breakage, or peeling of the first terminal electrode 17 will occur even under high-load conditions.

[0054] In addition, the formation of the solder foot surface 37 at the first terminal electrode 17 can increase the joint area between the first terminal 21a of the first wire 21 and the first terminal electrode 17, and can alleviate the stress concentration in the first terminal electrode 17, thereby improving the fixing force between the connected first terminal electrode 17 and the first terminal 21a of the first wire 21.

[0055] Furthermore, the formation of the solder foot surface 37 in the first terminal electrode 17 can mitigate the sharpness of the first terminal 21a of the first wire 21 protruding from the first terminal electrode 17. Therefore, as shown in the coil component 11, even at the first bottom surface 23 of the first flange portion 13, the structure in which the first terminal 21a of the first wire 21 is connected to the first terminal electrode 17 can easily prevent the wetting and spreading of the solder paste used for mounting. In addition, it is less likely to cause instability in the posture of the coil component 11 before it is fixed to the mounting substrate.

[0056] Figure 3 The illustrated embodiment has the following feature: on the surface of the first terminal 21a of the first wire 21 that is orthogonal to the extension direction, that is, on... Figure 3 When the dimensions were measured on paper, the width dimension W of the weld foot surface 37 in the direction parallel to the first bottom surface 23 of the first flange portion 13 is greater than the height dimension H in the direction orthogonal to the first bottom surface 23, from the first main surface 25 to the uppermost part of the weld foot surface 37.

[0057] The aforementioned features help to mitigate the sharpness of the protrusion of the first terminal 21a of the first wire 21 from the first terminal electrode 17. Therefore, this feature makes it less likely to hinder the wetting and spreading of the solder paste used for mounting, and also reduces the likelihood of instability in the posture of the coil component 11 before it is fixed to the mounting substrate.

[0058] in addition, Figure 3 The embodiment shown has the following feature: the uppermost part of the solder foot surface 37 reaches the top surface 33 of the first terminal 21a of the first wire 21.

[0059] Based on the above features, the bonding area between the first terminal electrode 17 and the first terminal 21a of the first wire 21 can be increased, thereby improving the fixing force between the connected first terminal electrode 17 and the first terminal 21a of the first wire 21. Furthermore, the exposed area of ​​the first terminal 21a of the first wire 21 exposed from the first terminal electrode 17 can be reduced. Therefore, similarly, it is less likely to hinder the wetting and spreading of the solder paste used for mounting, and it is less likely to cause instability in the posture of the coil component 11 before it is fixed to the mounting substrate.

[0060] The above explanation is for Figure 3 The description of the first terminal electrode 17 and the first terminal 21a of the first wire 21 is shown below. Figure 4 , Figure 5 as well as Figure 6 Similarly, in (A), only the first terminal electrode 17 and the first terminal 21a of the first wire 21 are illustrated. The present invention also relates to the case where the characteristic connection configuration is applied only to the connection portion between one terminal electrode and one terminal of the wire, but preferably to the connection portion between all terminal electrodes and the terminals of all wires connected thereto.

[0061] Therefore, considering that the connection structure of the present invention can be applied to the connection portion between all terminal electrodes and all wire terminals connected thereto, the top surface 33 of the first terminal 21a in the first wire 21 is called "first top surface 33", and the top surfaces of the aforementioned second terminal 21b, third terminal 22a, and fourth terminal 22b are respectively called "second top surface 34", "third top surface 35", and "fourth top surface 36". In addition, the solder foot surface 37 formed on the first terminal electrode 17 is called "first solder foot surface 37", and the solder foot surfaces formed on the second terminal electrode 18, third terminal electrode 19, and fourth terminal electrode 20 are respectively called "second solder foot surface 38", "third solder foot surface 39", and "fourth solder foot surface 40".

[0062] Reference Figure 4 The second embodiment of the present invention will be described. Figure 4 Is with Figure 3 The corresponding diagram. In Figure 4 In China, for the sake of Figure 3 Elements shown that correspond to each other are labeled with the same reference numerals as those in the accompanying drawings, and repeated descriptions are omitted.

[0063] Figure 4 The embodiment shown is characterized in that, when viewed on a surface orthogonal to the extension direction of the first terminal 21a of the first wire 21, the center C of the first terminal 21a in a direction orthogonal to the first bottom surface 23 of the first flange portion 13 (indicated by the double arrow) is located on the side of the first bottom surface 23 in a direction orthogonal to the first bottom surface 23, which is closer to the first bottom surface 23 than the position of the first main surface 25 of the first terminal electrode 17.

[0064] Based on the above features, the sharpness of the protrusion of the first terminal 21a of the first wire 21 relative to the first main surface 25 of the first terminal electrode 17 can be mitigated. Therefore, it is less likely to hinder the wetting and spreading of the solder paste used for mounting. In addition, it is less likely to cause instability in the posture of the coil component 11 before it is fixed to the mounting substrate.

[0065] Reference Figure 5 The third embodiment of the present invention will be described. Figure 5 Is with Figure 3 The corresponding diagram. In Figure 5 In China, for the sake of Figure 3 Elements shown that correspond to each other are labeled with the same reference numerals as those in the accompanying drawings, and repeated descriptions are omitted.

[0066] Figure 5 The embodiment shown is characterized in that the first solder foot surface 37 extends to a portion of the first top surface 33 covering the first terminal 21a of the first wire 21.

[0067] Based on the above characteristics, and Figure 3 Compared to the embodiment shown, the bonding area between the first terminal electrode 17 and the first terminal 21a of the first wire 21 can be further increased. Therefore, the fixing force between the connected first terminal electrode 17 and the first terminal 21a of the first wire 21 can be further improved. Furthermore, compared to... Figure 3 Compared to the embodiment shown, the exposed area of ​​the first terminal 21a of the first wire 21 exposed from the first terminal electrode 17 can be further reduced. Therefore, it is less likely to hinder the wetting and spreading of the solder paste used for mounting, and it is less likely to cause instability in the posture of the coil component 11 before it is fixed to the mounting substrate.

[0068] Reference Figure 6 The fourth embodiment of the present invention will be described. Figure 6 (A) and (B) are related to Figure 3 The corresponding diagram. In Figure 6 In (A) and (B), for those related to Figure 3 Elements shown that correspond to each other are labeled with the same reference numerals as those in the accompanying drawings, and repeated descriptions are omitted.

[0069] exist Figure 6 The diagram in (A) illustrates the connection between the first terminal electrode 17 and the first terminal 21a of the first wire 21. Figure 6 The diagram in (B) shows the connection between the second terminal electrode 18 and the second terminal 21b of the first wire 21. Figure 6 The embodiments shown have the following characteristics.

[0070] First, on the side of the first terminal electrode 17, as Figure 6 As shown in (A), the first terminal 21a of the first wire 21 is at least partially disposed within the first terminal electrode 17 and extends along the first main surface 25 of the first terminal electrode 17, and has a first top surface 33 located on the side opposite to the first bottom surface 23 of the first flange portion 13 than the first main surface 25. Moreover, a first solder foot surface 37 is formed on the outer surface of the first terminal electrode 17, which protrudes from the first main surface 25 toward the first top surface 33 and forms a concave curved surface.

[0071] On the other hand, on the second terminal electrode 18 side, such as Figure 6 As shown in (B), the second terminal 21b of the first wire 21 is at least partially disposed within the second terminal electrode 18 and extends along the second main surface 26 of the second terminal electrode 18, and has a second top surface 34 located on the side opposite to the second bottom surface 24 of the second flange portion 14 than the second main surface 26. Moreover, a second solder foot surface 38 is formed on the outer surface of the second terminal electrode 18, which protrudes from the second main surface 26 toward the second top surface 34 and forms a concave curved surface.

[0072] and, Figure 6 The illustrated embodiment is characterized in that the second solder pad 38 has a different shape than the first solder pad 37 described above. Here, "different shape of solder pads" means, for example... Figure 3 The weld foot surface shown has at least one of the following dimensions: height direction dimension H, width direction dimension W, aspect ratio (H / W), and curvature.

[0073] The reason why the shape of the first solder foot 37 is different from the shape of the second solder foot 38 is based on the following technical background.

[0074] At the beginning and end of the winding of the wire, the state of the wire (tension, contact angle with the terminal electrode, length) is different, but even if the difference is small, the optimal conditions for heat sealing are changed.

[0075] For example, regarding the first wire 21, when comparing the first terminal 21a connected to the first terminal electrode 17 and the second terminal 21b connected to the second terminal electrode 18, the tension of the first wire 21 is different in that either the first terminal 21a or the second terminal 21b becomes the winding start portion, and the other becomes the winding end portion. Furthermore, the tension of the first terminal 21a along the first terminal electrode 17... Figure 1 It traverses horizontally in the left and right directions, while the second terminal 21b originates from the second terminal electrode 18. Figure 1 The wire traverses horizontally from the lower left to the upper right along an inclined direction. Furthermore, the length of contact between the first terminal 21a and the first terminal electrode 17 is greater than the length of contact between the second terminal 21b and the second terminal electrode 18. Therefore, the state of the first wire 21 differs on the first terminal 21a side and the second terminal 21b side.

[0076] In this embodiment, depending on the different states of the first wire 21, more appropriate heat-pressing conditions are set independently on the first terminal 21a side and the second terminal 21b side. As a result, the shapes of the first solder pad 37 and the second solder pad 38 become different.

[0077] The heat-pressing conditions can be adjusted, for example, by changing the temperature, pressure, and duration of the welding head. Furthermore, to make the shape of the first welding lead 37 different from the shape of the second welding lead 38, the heat-pressing on the first terminal 21a side and the second terminal 21b side can be performed independently, or multiple independently controllable welding heads can be used simultaneously. Even when using the same welding head to simultaneously perform heat-pressing on the first terminal 21a side and the second terminal 21b side, the heat-pressing conditions can be adjusted by changing the contact position and angle between the welding head and the terminal electrode, or by changing the position and tension of the wire.

[0078] In addition, Figure 6 As an example, the second weld foot surface 38 is shown to have a relatively smaller width dimension W and a relatively larger curvature and aspect ratio compared to the first weld foot surface 37. However, it is not limited to this. Even if the width dimension W of the second weld foot surface 38 is relatively large and the curvature and aspect ratio are relatively small, the curvature and aspect ratio can be changed by making the width dimension W the same and the height dimension H different. Alternatively, the height dimension H and the width dimension W can be different.

[0079] As another embodiment of the present invention, if referred to Figure 1 To explain, the third terminal electrode 19, which is connected to the third terminal 22a of the second wire 22, can also have a third solder foot surface 39 formed on its outer surface, which protrudes from the third main surface 27 of the third terminal electrode 19 toward the third top surface 35 of the third terminal 22a and forms a concave curved surface.

[0080] In this case, the third terminal 22a is located at the third terminal electrode 19 from... Figure 1 The upper right to the lower left slopes horizontally, while the first terminal 21a is located at the first terminal electrode 17 along... Figure 1 It traverses horizontally in the left and right directions. Furthermore, the length of contact between the third terminal 22a and the third terminal electrode 19 is less than the length of contact between the first terminal 21a and the first terminal electrode 17. Therefore, the shape of the third solder pad 39 can also be different from the shape of the first solder pad 37.

[0081] As another embodiment of the present invention, if referred to Figure 1 To explain further, the fourth terminal electrode 20, which is connected to the fourth terminal 22b of the second wire 22, can also have a fourth solder foot surface 40 formed on its outer surface, which protrudes from the fourth main surface 28 of the fourth terminal electrode 20 toward the fourth top surface 36 of the fourth terminal 22b and forms a concave curved surface.

[0082] In this case, the fourth terminal 22b is located at the fourth terminal electrode 20 along... Figure 1 It traverses horizontally in the left and right directions, while the third terminal 22a is located at the third terminal electrode 19 from... Figure 1 It traverses horizontally from the upper right to the lower left along an inclined direction. Furthermore, the length of contact between the fourth terminal 22b and the fourth terminal electrode 20 is less than the length of contact between the third terminal 22a and the third terminal electrode 19. Therefore, the shape of the fourth solder face 40 can also be different from the shape of the third solder face 39.

[0083] The embodiments of the present invention have been described above with reference to the accompanying illustrations, but various other embodiments can be implemented within the scope of the present invention.

[0084] For example, the above embodiment relates to a coil component having two wires, but the present invention can also be applied to coil components having one wire or three or more wires. Therefore, the number of terminal electrodes can be changed corresponding to the number of wires.

[0085] in addition, Figure 3The embodiment shown has the following characteristics as described above: the width dimension W of the solder foot surface 37 is greater than the height dimension H up to the top of the solder foot surface 37; conversely, the width dimension W may be less than the height dimension H, or the width dimension W may be equal to the height dimension H.

[0086] in addition, Figure 4 The embodiment shown has the following feature: the center C of the terminal 21a in the direction orthogonal to the bottom surface 23 of the flange portion 13 is located on the side closer to the bottom surface 23 than the position of the main surface 25 of the terminal electrode 17 in the direction orthogonal to the bottom surface 23. It can be seen from the figure that the other embodiments shown also have the same feature. However, conversely, the center C of the terminal 21a in the direction orthogonal to the bottom surface 23 of the flange portion 13 may also be located on the side opposite to the bottom surface 23 than the position of the main surface 25 of the terminal electrode 17 in the direction orthogonal to the bottom surface 23.

[0087] in addition, Figure 3 The embodiment shown has the following characteristics: the uppermost part of the solder foot surface 37 reaches the top surface 33 of the terminal 21a of the wire 21, but the uppermost part of the solder foot surface 37 may not reach the top surface 33 of the terminal 21a of the wire 21, and the side of the terminal 21a of the wire 21 may be partially exposed.

[0088] Additionally, the coil component 11 includes a top plate 16 connecting the pair of flanges 13, 14. Alternatively, a coating material may be applied to the opposite side of each of the pair of flanges 13, 14 to the bottom surfaces 23, 24, covering the core portion 12 and the wires 21, 22. A resin containing magnetic powder is preferably used as the coating material. Alternatively, either the top plate 16 or the coating material may be omitted from the coil component 11.

[0089] Furthermore, the embodiments described in this specification are exemplary embodiments, and partial substitutions or combinations of structures can be made between different embodiments.

Claims

1. A coil component, wherein, have: The core has a core portion extending along an axial direction, and a first flange portion and a second flange portion respectively provided at a first end and a second end opposite to each other in the axial direction of the core portion; A first terminal electrode is disposed on the first flange portion; The second terminal electrode is disposed on the second flange portion; as well as The first wire is wound around the core portion. The first wire has a first terminal connected to the first terminal electrode and a second terminal connected to the second terminal electrode. The first flange portion has a first bottom surface facing the mounting surface side. The second flange portion has a second bottom surface facing the mounting surface side. The first terminal electrode has a first main surface extending along the first bottom surface. The second terminal electrode has a second main surface extending along the second bottom surface. The first terminal is at least partially disposed within the first terminal electrode and extends along the first main surface, and has a first top surface located on the side opposite to the first bottom surface from the first main surface. The outer surface of the first terminal electrode has a first solder foot surface that protrudes from the first main surface toward the first top surface and forms a concave curved surface. The second terminal is at least partially disposed within the second terminal electrode and extends along the second main surface, and has a second top surface located on the side opposite to the second bottom surface than the second main surface. The first top surface and the second top surface are flat.

2. The coil component according to claim 1, wherein, The first main surface and the second main surface are achieved by a soldering material layer made of tin or a tin alloy.

3. The coil component according to claim 1 or 2, wherein, When the dimensions of the first terminal are measured on the surface orthogonal to the extension direction, the width dimension of the first weld foot surface in the direction parallel to the first bottom surface is greater than the height dimension from the first main surface to the uppermost part of the first weld foot surface in the direction orthogonal to the first bottom surface.

4. The coil component according to any one of claims 1 to 3, wherein, The uppermost part of the first weld foot reaches the first top surface.

5. The coil component according to any one of claims 1 to 4, wherein, The first weld foot extends to a location that covers a portion of the first top surface.

6. The coil component according to any one of claims 1 to 5, wherein, When viewed on a surface orthogonal to the extension direction of the first terminal, the center of the first terminal in a direction orthogonal to the first bottom surface is located closer to the first bottom surface than the position of the first main surface in a direction orthogonal to the first bottom surface.

7. The coil component according to any one of claims 1 to 6, wherein, The outer surface of the second terminal electrode has a second solder foot surface that protrudes from the second main surface toward the second top surface and forms a concave curved surface.

8. The coil component according to claim 7, wherein, The second weld foot surface has a different shape than the first weld foot surface.

9. The coil component according to any one of claims 1 to 8, wherein, It also has: The third terminal electrode is disposed on the first bottom surface; A fourth terminal electrode is disposed on the second bottom surface; and The second wire is wound around the core portion in the same direction as the first wire. The second wire has a third terminal connected to the third terminal electrode and a fourth terminal connected to the fourth terminal electrode. The third terminal electrode has a third main surface extending along the first bottom surface. The fourth terminal electrode has a fourth main surface extending along the second bottom surface. The third terminal is at least partially disposed within the third terminal electrode and extends along the third main surface, and has a third top surface located on the side opposite to the first bottom surface than the third main surface. The outer surface of the third terminal electrode has a third solder foot surface that protrudes from the third main surface toward the third top surface and forms a concave curved surface.

10. The coil component according to claim 9, wherein, The third weld foot surface has a different shape than the first weld foot surface.

11. The coil component according to claim 9 or 10, wherein, The fourth terminal is at least partially disposed within the fourth terminal electrode and extends along the fourth main surface, and has a fourth top surface located on the side opposite to the second bottom surface than the fourth main surface. The outer surface of the fourth terminal electrode has a fourth solder foot surface that protrudes from the fourth main surface toward the fourth top surface and forms a concave curved surface.

12. The coil component according to claim 11, wherein, The fourth weld foot has a different shape than the third weld foot.

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