Coil device

Abstract

This coil device (1) is provided with: a coil (2) having: a lead-out section (3a) having a first surface (31) and a second surface (32) on the opposite side from the first surface (31); and a terminal (5a) that is connected to the lead-out portion (3a) via a welding portion (56a). The terminal (5a) has an opposing surface (511) facing the first surface (31) of the lead-out portion (3a). The second surface (32) of the lead-out part (3a) has a non-welding surface (6) at a position opposite to the position where the welding part (56a) is disposed.

Description

Technical Field

[0001] This disclosure relates to a coil device used as, for example, an inductor. Background Technology

[0002] As a coil device for inductors, etc., a coil device as described in Patent Document 1 is known. In the coil device of Patent Document 1, the coil and the terminal electrodes for external connection are connected by laser welding.

[0003] However, in this type of laser welding, in order to reliably connect the coil to the terminal electrode, the terminal electrode and the wire are fused together to form a fused weld bead. In this case, it is not easy to control the size of the weld bead, and sometimes the weld bead becomes too large.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-182245 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] This disclosure was made in view of this practical situation, and its purpose is to provide a coil device for miniaturizing the welding of the coil and terminal electrodes.

[0009] Technical solutions for solving the problem

[0010] One aspect of the coil device disclosed herein, wherein...

[0011] have:

[0012] A coil having: a lead-out portion having a first surface and a second surface opposite to the first surface; and

[0013] The terminal is connected to the lead-out portion via a solder joint.

[0014] The terminal has a surface opposite to the first surface facing the lead-out portion.

[0015] The second surface of the lead-out portion has a non-welded surface on the opposite side from the position where the welding portion is located.

[0016] With this configuration, the lead-out portion is securely connected to the terminal via a solder joint formed on the first side of the lead-out portion. Furthermore, in this coil assembly, since large solder balls are not required, energy consumption during product manufacturing can be reduced, and the impact of heat from soldering on the coil can be minimized.

[0017] Furthermore, in one aspect of the coil device disclosed herein, wherein,

[0018] have:

[0019] A coil having: a lead-out portion having a first side and a second side opposite to the first side;

[0020] Terminals, which are connected to the leads via soldering portions; and

[0021] The body contains the coil embedded within it.

[0022] The terminal has a surface opposite to the first surface facing the lead-out portion.

[0023] The second surface of the lead-out portion has a non-welded surface on the opposite side from the position where the welding portion is located.

[0024] With this configuration, the lead-out portion is securely connected to the terminal via a solder joint formed on the first side of the lead-out portion. Furthermore, in this coil assembly, since large solder balls are not required, energy consumption during product manufacturing can be reduced, and the impact of heat from soldering on the coil can be minimized. Additionally, compared to conventional coil assemblies that require large solder balls, the solder joint is sufficiently small, thus ensuring adequate volume of the coil even when it is embedded within the body. Therefore, this coil assembly improves product characteristics.

[0025] Alternatively, the front end of the lead-out portion can protrude further outward than the terminal. This configuration facilitates the formation of small weld joints at designated locations.

[0026] Alternatively, the welded portion may have a welded surface that is inclined toward the front end of the lead-out portion. With this configuration, the welded portion can be formed to be thinner than the combined thickness of the terminal and the lead-out portion, while sufficiently ensuring connection strength.

[0027] Alternatively, the length of the welding surface of the welded portion along the lead-out direction of the lead-out portion can be shorter than the length of the opposite surface of the terminal along the lead-out direction. With this configuration, the welded portion can be reduced in size, and the connection strength between the lead-out portion and the terminal can be sufficiently ensured.

[0028] Alternatively, a plating layer can be formed on the opposite surface of the terminal. In this way, even if the plating layer of the terminal remains unmelted, the connection strength between the lead and the terminal can be sufficiently ensured.

[0029] Alternatively, the surface roughness of the welding surface of the welded portion can be greater than the surface roughness of the non-welded surface of the second surface of the lead-out portion. In this laser welding process with a welded surface, the lead-out portion and the terminal can be firmly connected. Furthermore, it is easy to attach a substrate to this welded surface, thereby improving the bonding strength between the welded portion and the substrate.

[0030] Alternatively, a resin coating may be formed on the second surface of the lead-out portion. Even if the resin coating on the second surface is not removed during manufacturing, the lead-out portion can still be connected to the terminal on the first surface side. Furthermore, during laser welding, even with a weak output where heat does not transfer to the second surface side, the connection strength between the lead-out portion and the terminal can be sufficiently ensured. In this coil device, since it is not necessary to form large solder balls, energy consumption during product manufacturing can be reduced, and the impact of heat during welding on the coil can be minimized.

[0031] Alternatively, the coil can be made of flat wire. In a coil formed of flat wire, even without being wound with terminals, the lead-out portion can easily contact the terminals, and a solder joint can easily be formed at a specified position. Attached Figure Description

[0032] Figure 1 This is a perspective view of the coil device according to one embodiment.

[0033] Figure 2A yes Figure 1 A three-dimensional view of a portion of the structure of the coil device shown.

[0034] Figure 2B It is a different perspective. Figure 2A A three-dimensional view of the portion shown.

[0035] Figure 3 yes Figure 2A The front view of the portion shown.

[0036] Figure 4 yes Figure 2A The top view of the portion shown.

[0037] Figure 5 yes Figure 2A The cross-sectional view at the VV line shown.

[0038] Figure 6 yes Figure 2A The enlarged side view shown.

[0039] Figure 7 It indicates assembly. Figure 1 A three-dimensional view of the structure of the coil preceding the coil device shown.

[0040] Figure 8 It indicates assembly. Figure 1 A perspective view of the structure of the terminals preceding the coil assembly shown.

[0041] Figure 9 It means Figure 1 A perspective view of an example of the core of the coil device shown.

[0042] Figure 10 It means Figure 1 A diagram illustrating an example of the manufacturing process of the coil device.

[0043] Figure 11 It means Figure 10 The diagram shows the successive processes of the manufacturing process.

[0044] Figure 12 It means Figure 11 The diagram shows the successive processes of the manufacturing process.

[0045] Explanation of reference numerals in the attached figures

[0046] 1…coil assembly; 2…coil; 20…winding section; 3 (3a, 3b)…lead-out section; 31…first surface; 32…second surface; 33…third surface; 34…fourth surface; 36…front end; 37…resin coating; 500…conductive plate; 5 (5a, 5b)…terminal; 51a, 51b…wiring section; 511…opposite non-welded surface; 512…opposite non-welded surface; 513, 514…side non-welded surface; 52a, 52b…base; 520…main branch; 521… Sub-branch; 53a, 53b…connecting part; 54a, 54b…mounting part; 55…plating; 56a, 56b…welding part; 561…welding surface; 6…non-welding surface; 7…body; 7a…first outer surface; 7b…second outer surface; 7c…third outer surface; 7d…fourth outer surface; 7e…fifth outer surface; 7f…sixth outer surface; 70…side recess; 71…first core; 710…shaft core; 72…second core; 720…accommodating recess; 100, 101…laser irradiation position Detailed Implementation

[0047] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Furthermore, the illustrations are merely schematic and illustrative for the purpose of understanding the present disclosure, and their appearance and size ratios may differ from the actual product. Additionally, the present disclosure is not limited to the following embodiments.

[0048] Figure 1 The coil device 1 shown in this embodiment is a surface-mount inductor, which can be installed, for example, in the power circuit of an electronic device. The size of the coil device 1 is not particularly limited, but its width in the X-axis direction is preferably 2 to 20 mm, its width in the Y-axis direction is preferably 2 to 20 mm, and its width in the Z-axis direction is preferably 1 to 10 mm.

[0049] The coil assembly 1 includes a coil 2 and terminals 5. Additionally, the coil assembly 1 has a core 7 with the coil 2 embedded inside as its base. The shape of the core 7 is not particularly limited. Figure 1 In the example shown, the surface has a generally rectangular parallelepiped shape and includes a first outer surface 7a, a second outer surface 7b, a third outer surface 7c, a fourth outer surface 7d, a fifth outer surface 7e, and a sixth outer surface 7f. The first and second outer surfaces 7a and 7b are opposite each other in a first direction, the third and fourth outer surfaces 7c and 7d are opposite each other in a second direction, and the fifth and sixth outer surfaces 7e and 7f are opposite each other in a third direction. The first, second, and third directions are orthogonal to each other.

[0050] Furthermore, in the attached diagram, the X-axis corresponds to the first direction, the Y-axis corresponds to the second direction, and the Z-axis corresponds to the third direction. The origin of the XYZ coordinate system is set at the center of core 7. For each of the X, Y, and Z axes, the side closer to the origin in a positive direction is sometimes referred to as "one side," the side closer to the origin in a negative direction is sometimes referred to as "the other side," the direction away from the origin is sometimes referred to as "outer side," and the direction closer to the origin is sometimes referred to as "inner side."

[0051] The core 7 can be formed of a material containing a magnetic element (magnetic material). Alternatively, the core 7 may also contain resin. The core 7 can be formed, for example, by... Figure 9 The preformed first core 71 and second core 72 shown are compressed and integrally formed inside a mold. Alternatively, the core 7 can be formed, for example, by injection molding or machining.

[0052] Examples of magnetic materials forming the core 7 include ferrite particles or metallic magnetic particles. Examples of ferrite particles include Ni-Zn ferrites and Mn-Zn ferrites. Examples of metallic magnetic particles are not particularly limited and include Fe-Ni alloy powder, Fe-Si alloy powder, Fe-Si-Cr alloy powder, Fe-Co alloy powder, Fe-Si-Al alloy powder, and amorphous iron. Examples of resins forming the core 7 are not particularly limited and include epoxy resin, phenolic resin, polyester resin, polyurethane resin, polyimide resin, silicone resin, other synthetic resins, or other non-magnetic materials. Alternatively, the core 7 can also be a sintered body of a metallic magnetic material.

[0053] like Figure 1 As shown, coil 2 has a winding portion 20 and lead-out portions 3a and 3b. Lead-out portion 3a is soldered to terminal 5a, and lead-out portion 3b is soldered to terminal 5b. Coil 2 exemplifies a flat-wound coil formed by winding a conductor in an α-shape. Furthermore, in this specification, lead-out portions 3a and 3b are sometimes referred to collectively as lead-out portion 3. Additionally, in this embodiment, terminals 5a and 5b are sometimes referred to collectively as terminal 5.

[0054] Figure 7 This refers to coil 2 before assembly. (e.g., ...) Figure 7 As shown, the coil 2 is composed of a wire having a first surface 31 that can face the terminal and a second surface 32 on the opposite side. In this embodiment, the wire constituting the coil 2 can be a flat wire connected by the first surface 31, the second surface 32, the third surface 33 and the fourth surface 34, but it is not limited to this and can also be a square wire, a round wire, a stranded wire, etc.

[0055] By forming the coil 2 from flat wire, it is easy to solder the lead wire 3 to the terminal 5. From the same perspective, the wire constituting the coil 2 can also be a wire with a roughly elliptical cross-section, formed by flattening a round wire. By forming the coil 2 from flat wire, a larger current can flow through the coil 2, and deformation of the coil 2 is less likely, resulting in a high-quality coil device 1. In the coil 2 formed from flat wire, even without winding with the terminal, the lead can easily contact the terminal, and the solder joint described later can easily be formed at a specified position. Furthermore, the winding method of the wire constituting the coil 2 is not limited to α-winding and can be appropriately modified.

[0056] The material used for the conductors constituting coil 2 is not particularly limited, and examples include copper and copper alloys, silver, or nickel. In particular, copper and copper alloys are preferred as the material for the conductors constituting coil 2. Furthermore, it is preferable that the conductors constituting coil 2, except for the portion soldered to the terminal, are coated with a resin film. The material used for the resin film is not particularly limited, and examples include polyamide-imide resin or polyurethane resin. Moreover, when assembling the coil assembly, it is preferable to remove the resin film from the lead-out portion 3 at the portion soldered to the terminal.

[0057] like Figure 1 As shown, lead-out portion 3a of coil 2 is located in the layer above the Z-axis of winding portion 20, and extends to one side (towards the third outer surface 7c) along the Y-axis. Lead-out portion 3b of coil 2 is located in the layer below the Z-axis of winding portion 20, and extends to one side (towards the third outer surface 7c) along the Y-axis. Lead-out portions 3a and 3b are staggered in position along the Z-axis direction.

[0058] like Figure 2A As shown, terminal 5a has a wiring portion 51a, a base 52a, a connecting portion 53a, and a mounting portion 54a. Figure 2B As shown, terminal 5b has a wiring portion 51b, a base 52b, a connecting portion 53b, and a mounting portion 54b. Terminals 5a and 5b can be formed, for example, by machining a conductive sheet such as metal.

[0059] like Figure 2A , Figure 2B and Figure 3 As shown, the wiring portion 51a is configured approximately orthogonal to the lead-out portion 3a. The wiring portion 51b is configured approximately orthogonal to the lead-out portion 3b. (As shown...) Figure 3 As shown, in this embodiment, along the Z-axis, the wiring portion 51b is shorter than the wiring portion 51a. The wiring portion 51a is welded to the lead-out portion 3a via the welding portion 56a, and the wiring portion 51b is welded to the lead-out portion 3b via the welding portion 56b.

[0060] The following is a detailed description of the wiring section 51a and its surrounding parts. This description also applies to the wiring section 51b and its surrounding parts; therefore, only matters of particular necessity will be explained for the latter.

[0061] like Figure 2A As shown, the wiring portion 51a has a generally cuboid shape comprising a facing surface 511 having a lead-out portion 3a that can face the coil, a reverse facing surface 512 opposite to the facing surface 511, and side surfaces 513 and 514. Furthermore, as described later, a portion of the side surface 513 is fused. In this embodiment, the facing surface 511 and the reverse facing surface 512 are arranged substantially parallel to the ZY plane.

[0062] like Figure 2A , Figure 2B , Figure 3 and Figure 4 As shown, the opposite surface 511 of the wiring portion 51a faces the first surface 31 of the lead-out portion 3a from the outer side in the X-axis direction. The wiring portion 51a is welded to the lead-out portion 3a via a welding portion 56a. The welding portion 56a is a fusion of the lead-out portion 3a and the wiring portion 51a, and is arranged along the Y-axis on the outer side of the wiring portion 51a.

[0063] The welded part 56a has a welded surface with unevenness. In contrast, as... Figure 4 As shown, the non-welded surface 6 of the solder portion 56a, which is not exposed, is smooth in the wiring portion 51a and the lead-out portion 3a. That is, in this embodiment, the surface roughness (arithmetic mean height) of the solder surface 561 is greater than the surface roughness (arithmetic mean height) of the surface of the portion of the wiring portion 51a and the lead-out portion 3a where the solder portion is not formed (non-welded surface 6).

[0064] Figure 5 yes Figure 2A The cross-sectional view at the VV line of the welded part 56a and its surrounding part is shown. Figure 6 yes Figure 2A A side view of the welded portion 56a and its surrounding area. (See attached image.) Figure 5 As shown, the welding part 56a is formed by fusing a portion of the wiring part 51a along the outer side of the Y-axis and a portion of the lead-out part 3a along the inner side of the X-axis.

[0065] like Figure 5As shown, the outer end of the opposite surface 511 of the wiring portion 51a along the Y-axis is connected to the welding portion 56a. Additionally, the outer end of the first surface 31 of the lead-out portion 3a facing the opposite surface 511 along the Y-axis is also connected to the welding portion 56a. In this embodiment, a gap is formed between the opposite surface 511 and the first surface 31, but they can also be in close contact. Furthermore, the opposite surface 511 and the first surface 31 can be inclined relative to each other or parallel.

[0066] Figure 5 The thickness W2 of the wiring portion 51a shown is not particularly limited. For example, the thickness W2 of the wiring portion 51a may be 0.1 to 10 times the thickness W3 of the lead-out portion 3a.

[0067] In this embodiment, a plating layer 55 is formed on the surface of the opposing surface 511. The plating layer 55 may be, for example, Sn plating. When the plating layer 55 is Sn plating, the surface of the opposing surface 511 may have more Sn than the first surface 31 of the lead-out portion 3a.

[0068] Furthermore, the plating 55 can also be applied to the base 52a, the connecting portion 53a, and the mounting portion 54a (see reference). Figure 2A (etc.) continuous. With this configuration, a plating layer 55 can be pre-formed on the conductive plate, which becomes the material of terminal 5a.

[0069] In this embodiment, a resin coating 37 may also be formed on the second surface 32 of the lead-out portion 3a. As will be described later, if the output of laser irradiation used to form the weld portion 56a is reduced, the resin coating 37 can remain without deterioration even if it is formed on the second surface 32.

[0070] like Figure 5 and Figure 6 As shown, in this embodiment, the weld portion 56a is formed by melting a portion of the side surface 513, and is not formed on the opposite side surface 512 and side surface 514. Furthermore, in this embodiment, the weld portion 56a is not disposed on the front end 36 and the second surface 32 of the lead-out portion 3a. However, a portion of the weld portion 56a may also be disposed on the front end 36, the third surface 33, the fourth surface 34, etc. Figure 5 As shown, at least in the lead-out portion 3a, the second surface 32 at the position opposite to the position where the welding portion 56a is disposed is not disposed of, and at this position, the second surface 32 is a non-welding surface 6 with a surface roughness (arithmetic mean height) that is less than that of the welding surface 561.

[0071] like Figure 5 As shown, the welding surface 561 of the welding part 56a is inclined toward the front end 36 of the lead-out part 3a. The width of the welding part 56a in the X-axis direction is less than the width W1 from the opposite surface 512 of the wiring part 51a to the second surface 32 of the lead-out part 3a.

[0072] In this embodiment, the length L2 of the opposite surface 512 along the Y-axis is not particularly limited, and can be, for example, 1 to 10 times the thickness W2 of the wiring portion 51a. The length L1 of the welding surface 561 of the welding portion 56a along the Y-axis of the lead-out portion 3a is shorter than the length L3 of the opposite surface 511 of the wiring portion 51a along the Y-axis. In this embodiment, since the welding portion 56a is formed, the length L3 of the opposite surface 511 along the Y-axis is shorter than the length L2 of the opposite surface 512 along the Y-axis.

[0073] like Figure 2A and Figure 2B As shown, the base 52a is integrally connected to one side of the Z-axis of the wiring portion 51a. The base 52b is integrally connected to one side of the Z-axis of the wiring portion 51b. The bases 52a and 52b serve to hold the wiring portions 51a and 51b together.

[0074] The bases 52a and 52b each have a main branch 520 and a secondary branch 521, respectively. Except for a portion, the bases 52a and 52b share a common shape. The bases 52a and 52b are arranged approximately parallel to the XY plane. Figure 2A and Figure 2B As shown, the bases 52a and 52b are positioned along the Z-axis closer to the fifth outer surface 7e than coil 2 (see reference). Figure 1 )side.

[0075] like Figure 2A and Figure 2B As shown, the connecting portions 53a and 53b have surfaces that are substantially parallel to the YZ plane and extend upwards from the base 52a and 52b. Figure 1 As shown, the connecting portion 53a is located at a position separating it from the fifth outer surface 7e of the core 7, exposed on the first outer surface 7a of the core 7 in the X-axis direction, and extends along the first outer surface 7a to the sixth outer surface 7f of the core 7. The connecting portion 53b is located at a position separating it from the fifth outer surface 7e of the core 7, exposed on the second outer surface 7b of the core 7 in the X-axis direction, and extends along the second outer surface 7b to the sixth outer surface 7f of the core 7.

[0076] like Figure 1 As shown, mounting portion 54a is connected to the Z-axis end of connecting portion 53a and extends inward toward the X-axis. Mounting portion 54b is connected to the Z-axis end of connecting portion 53b and extends inward toward the X-axis. Mounting portions 54a and 54b have surfaces parallel to the XY plane and are formed along the sixth outer surface 7f of core 7. Mounting portions 54a and 54b are exposed outside core 7 on the sixth outer surface 7f and are connected to circuit board or the like (not shown) when mounting coil device 1.

[0077] Mounting portions 54a and 54b are connected to the circuit board or the like via connecting members such as solder or conductive adhesive. At this time, solder joints can be formed on the connecting portions 53a and 53b. This improves the mounting strength of the coil assembly 1 relative to the circuit board or the like. Furthermore, the aforementioned plating layer 55 (see reference) can be formed on the surfaces of the mounting portions 54a and 54b and the connecting portions 53a and 53b. Figure 5 By forming the plating layer 55, the wettability of the mounting portions 54a, 54b and the connecting portions 53a, 53b is improved, and the solder joints are formed well.

[0078] Existing coil devices connect the coil and terminals by making large solder balls. In contrast, as described above, in the coil device 1 of this embodiment, at least the second surface 32 of the lead-out portion 3 is on the opposite side from the position where the solder portions 56a and 56b are arranged, becoming a non-soldering surface 6 (see reference). Figure 4 (etc.). Thus, in this embodiment, the welding portions 56a and 56b are formed in a very small portion on the first surface 31 side of the lead-out portion 3. Therefore, the volume of the magnetic material forming the core 7 can be sufficiently ensured, and the characteristics of the product can be improved. In addition, the welding portions 56a and 56b can sufficiently ensure the connection strength between the lead-out portion 3 and the terminal 5. Furthermore, in the coil device 1 of this embodiment, the impact on the coil 2 caused by welding is sufficiently small. Therefore, in the coil device 1 of this embodiment, the product strength can be sufficiently ensured.

[0079] like Figure 4 As shown, the front end 36 of the lead-out portion 3 protrudes further outward along the Y-axis than the wiring portion of the terminal 5. Furthermore, the solder portions 56a and 56b have solder surfaces 561 that are inclined towards the front end 36 of the lead-out portion 3. Thus, the solder portions 56a and 56b are formed to be thinner than the combined thickness of the terminal 5 and the lead-out portion 3. Additionally, the solder portions 56a and 56b can be easily formed in a smaller size at a predetermined position and firmly soldered.

[0080] like Figure 5 As shown, in the coil device 1 of this embodiment, the length L1 of the welding surface 561 of the welding portion 56a along the lead-out direction of the lead-out portion 3a is shorter than the length L2 of the opposite surface 511 of the terminal wiring portion 51 along the lead-out direction. With this configuration, the welding portion 56a can be reduced in size, and the connection strength between the lead-out portion 3a and the terminal wiring portion 511 can be sufficiently ensured.

[0081] Furthermore, in this embodiment, the length L3 of the opposite surface 511 of the connector 51a along the Y-axis is shorter than the length L2 of the opposite surface 512 along the Y-axis. A welded portion 56a is formed by melting a portion of the opposite surface 511. By forming the welded portion 56a at this location, the connector 51a and the lead-out portion 3a are well welded, improving product strength. Moreover, in this embodiment, the plating 55 remains unmelted on the opposite surface 511 of the connector 51a; even in this case, the connection strength between the connector 51a and the lead-out portion 3a is sufficiently ensured.

[0082] The surface roughness (arithmetic mean height) of the welding surface 561 of the welding portions 56a and 56b is greater than the surface roughness (arithmetic mean height) of the non-welding surface 6 of the second surface 32 of the lead-out portions 3a and 3b. In laser welding where a welding surface 561 with a rougher surface than the second surface is formed, the lead-out portions 3a and 3b are firmly connected to the wiring portions 51a and 51b. Furthermore, the substrate easily adheres to this welding surface, thereby improving the bonding strength between the welding portion and the substrate.

[0083] Furthermore, the difference in surface roughness between the welded surface 561 and the non-welded surface 6 can be confirmed by cutting the core 7 around the welded portions 56a and 56b with a cutting tool (and then destroying it with heat), observing the exposed wiring portions 51a and 51b, welded portions 56a and 56b, and lead-out portions 3a and 3b with a laser microscope, or by observing them with a scanning electron microscope at a magnification of 100x to 5000x.

[0084] The coil device 1 of this embodiment can be manufactured, for example, as follows. Hereinafter, refer to... Figures 7-12 Here, an example of the manufacturing method of coil device 1 will be described. First, prepare... Figure 7 Coil 2 is shown.

[0085] Next, the conductive plate 500, which will become the material for terminals 5a and 5b, such as a metal plate (e.g., a Sn-plated metal plate), is stamped into shape. Figure 8 The shape is as shown. Furthermore, the conductive plate 500 can also be connected to a large frame (not shown). In this state, the sides 513 of the wiring portions 51a and 51b are not fused.

[0086] Next, as Figure 10 and Figure 11 As shown, coil 2 is positioned between terminals 5a and 5b. At this time, the resin coating on the portions of coil 2 that contact the wiring portions 51a and 51b can also be removed.

[0087] Next, as Figure 10As shown, a laser is irradiated at the laser irradiation position 100 using a known method, causing a portion of the wiring portion 51a and a portion of the lead-out portion 3a to melt, forming the aforementioned welding portion 56a (see reference). Figure 2A (etc.). Thus, the lead-out portion 3a is soldered to the wiring portion 51a. Additionally, as... Figure 11 As shown, laser light is applied to laser irradiation position 101 using a known method, causing a portion of the wiring portion 51b and a portion of the lead-out portion 3b to melt, forming the aforementioned welded portion 56b (see reference). Figure 2B (etc.). In this way, lead-out part 3b is soldered to wiring part 51b.

[0088] By irradiating the wires with laser in this way, damage caused by laser irradiation can be reduced. Furthermore, there are no particular limitations on the laser output or the number of irradiations; from the viewpoint of reducing product costs, low-output and fewer irradiations are also possible. By irradiating with low output laser, the resin coating 37 formed on the second surface 32 of the leads 3a and 3b can remain after this process. Even with a weak output where the heat from laser irradiation does not transfer to the second surface 32, the connection strength between the leads 3a and 3b and the wiring portions 51a and 51b can be sufficiently ensured, thus reducing energy consumption during product manufacturing.

[0089] Next, coil 2 is embedded in the body. For example, at this point, as the body, it is pre-formed... Figure 9 The first core 71 and the second core 72 as shown, such as Figure 11 As shown, the coil 2 is placed into the receiving recess 720 of the second core 72, and the shaft core portion 710 of the first core 71 is inserted into the winding portion 20 of the coil 2, respectively, to form a configuration. Figure 12 The temporary assembly shown. As the materials constituting the first core 71 and the second core 72, a fluid material can be used, or a composite magnetic material using a thermoplastic resin or a thermosetting resin as a binder can be used.

[0090] Next, using the mold's fixtures (upper and lower punches, etc.), the mold is... Figure 12 The first core 71 and the second core 72 of the temporary assembly shown are compressed and molded together to form core 7.

[0091] Next, connecting portions 53a and 53b are disposed in the side recesses 70 formed in the core 7. Furthermore, in Figure 8 When the conductor plate 500 shown is connected to the frame, then, as Figure 12 In the same manner, the conductor plate 500 is cut from the frame. Figure 12 As shown, the connecting portions 53a and 53b of terminals 5a and 5b are connected from... Figure 12The connecting portions 53a and 53b are bent approximately vertically in the state shown, and are positioned in the side recesses 70 on the side of the core 7 in the X-axis direction. Furthermore, in this state, the front ends of the connecting portions 53a and 53b are bent approximately vertically and positioned at the ends of the side recesses 70 reaching the sixth outer surface 7f of the core 7. Thus, mounting portions 54a and 54b for the terminals 5a and 5b are formed on the sixth outer surface 7f of the core 7. As described above, the coil device 1 of this embodiment can be obtained.

[0092] Currently, when combining two cores and embedding the coil within the core, the receiving recess of the core needs to be formed relatively large to accommodate large solder balls. In contrast, in this embodiment, as... Figure 9 and Figure 11 As shown, the portion corresponding to the welding portion 56 in the receiving recess 720 of the second core 72 can be reduced. Therefore, the volume of the magnetic material forming the core 7 can be sufficiently ensured, thereby improving the product's characteristics. Furthermore, in this embodiment, large solder balls are not required; therefore, less energy is needed for laser welding, improving energy efficiency during product manufacturing.

[0093] Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the present invention.

[0094] The above embodiments illustrate applications of the invention to inductors, but the invention can also be applied to coil devices other than inductors.

[0095] In the embodiments described above, the conductor constituting coil 2 is a flat wire, but it can also be a wire other than a flat wire, such as a square wire or a round wire. When the conductor constituting coil 2 is a round wire, the first surface 31 of the lead-out portion (refer to...) Figure 5 The second surface 32 is the surface on the opposite side of the outer periphery of the circle (etc.).

[0096] In the above implementation methods, such as Figure 3 As shown, the welding portions 56a and 56b are formed on the outer side surface 513 along the Y-axis of the wiring portions 51a and 51b, but the welding portions 56a and 56b may also be formed on the inner side surface 514 along the Y-axis.

[0097] In the above embodiment, the winding shape of the winding portion 20 of the coil 2 is set to a circular spiral, but it can also be, for example, an elliptical spiral or a square spiral.

Claims

1. A coil device, wherein, have: A coil having: a lead-out portion having a first side and a second side opposite to the first side; as well as The terminal is connected to the lead-out portion via a solder joint. The terminal has a surface opposite to the first surface facing the lead-out portion. The second surface of the lead-out portion has a non-welded surface on the opposite side from the position where the welding portion is located.

2. A coil device, wherein, have: A coil having: a lead-out portion having a first side and a second side opposite to the first side; Terminals, which are connected to the leads via soldering portions; and The body contains the coil embedded within it. The terminal has a surface opposite to the first surface facing the lead-out portion. The second surface of the lead-out portion has a non-welded surface on the opposite side from the position where the welding portion is located.

3. The coil device according to claim 1 or 2, wherein, The front end of the lead-out portion protrudes further outward than the terminal.

4. The coil device according to claim 3, wherein, The welded portion has a welded surface that is inclined toward the front end of the lead-out portion.

5. The coil device according to claim 1 or 2, wherein, The length of the welding surface of the welding part along the lead-out direction of the lead-out part is shorter than the length of the opposite surface of the terminal along the lead-out direction.

6. The coil device according to claim 1 or 2, wherein, A plating layer is formed on the opposite surface of the terminal.

7. The coil device according to claim 1 or 2, wherein, The surface roughness of the welded surface of the welded part is greater than the surface roughness of the non-welded surface of the second surface of the lead-out part.

8. The coil device according to claim 1 or 2, wherein, A resin coating is formed on the second surface of the lead-out portion.

9. The coil device according to claim 1 or 2, wherein, The coil is made of flat wire.

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