Inductor and method of manufacturing an inductor

Abstract

The present disclosure can suppress a decrease in reliability of an inductor. The inductor includes a magnetic core, a coil element embedded in the magnetic core, and an electrode member connected to the coil element. The coil element has a winding portion in which a wire with an insulating coating is wound, and a lead portion (23) that is drawn out from an end portion of the winding portion. The electrode member has a side plate portion, a first lead-out portion (31) that extends from the side plate portion toward an inside of the magnetic core, and a connection portion (34) that includes a second riveting portion (34b) and a first riveting portion (34a), and that sandwiches and rivets the lead portion (23) with the second riveting portion (34b) and the first riveting portion (34a) in the inside of the magnetic core. The connection portion (34) has a welded portion (34m) in which the connection portion (34) and the lead portion (23) are fused and solidified between a first fusion mark (34ma) and a second fusion mark (34mb).

Description

Technical Field

[0001] This disclosure relates to inductors and methods of manufacturing inductors. Background Technology

[0002] In recent years, with the increasing performance of electronic devices, there is a growing demand for miniaturized devices that can handle larger currents, creating a need for inductors that meet both requirements.

[0003] As an example of such conventional inductors, it is known that an inductor is formed by covering a coil with magnetic powder and pressing the magnetic powder to form a magnetic core. Patent Document 1 proposes an electronic component (inductor) in which a pair of terminals of the winding portion of the coil component, which is composed of conductive wire, are riveted and fixed to a riveting retaining portion of a terminal plate, and fixed by resistance welding, and the portion of the terminals and the riveting retaining portion that is resistance welded is disposed within the magnetic core. Existing technical documents Patent documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2020-43370 Summary of the Invention

[0005] However, regarding the inductor disclosed in Patent Document 1, when the material of the conductive wire of the coil component and the material of the plate for the terminals are high-purity copper materials such as ductile copper, copper has low resistivity and therefore does not easily generate heat. In addition, due to its high thermal conductivity, heat is easily dissipated. Therefore, even if resistance welding is performed, it is difficult to obtain a weld nugget (weld part), and it is easy to become a diffusion bond. If the bond part in this diffusion bond state is covered with magnetic powder and pressure molded, the bond part may fall off due to insufficient strength.

[0006] Therefore, to increase connection strength, it is considered to use the large heat from laser welding to melt the riveting part of the wire and the terminal plate to form a molten ball joint. However, in small inductors, because the distance between the joint and the insulating film of the coil winding and the coil lead is short, the insulating film of the wire deteriorates due to the heat during welding. Specifically, the insulating film foams and becomes cloudy, which damages the reliability of the inductor.

[0007] Therefore, in view of the above-mentioned problems, this disclosure provides an inductor capable of suppressing the reduction of inductor reliability and a method for manufacturing the inductor.

[0008] One aspect of the inductor disclosed herein includes: a magnetic core having a bottom surface, a top surface opposite to the bottom surface, and an end surface connecting the bottom surface and the top surface; a coil element embedded in the magnetic core; and an electrode component connected to the coil element. The coil element has a wound portion with a wire wrapped with an insulating film and a lead portion extending from the end of the wound portion. The electrode component has: a side plate portion disposed along the end surface; a first lead portion extending from the end of the side plate portion on the top surface side into the interior of the magnetic core; and a connecting portion connected to the first lead portion, and sequentially including a second riveting portion and a first riveting portion in order of proximity to the first lead portion. The connecting portion clamps and rivets the lead portion inside the magnetic core using the second riveting portion and the first riveting portion. The connecting portion has: a first melt mark formed by melting and solidifying the first riveting portion on the surface of the first riveting portion; a second melt mark formed by melting and solidifying the second riveting portion on the surface of the second riveting portion; and a welded portion formed by melting and solidifying the connecting portion and the lead portion between the first melt mark and the second melt mark.

[0009] Another aspect of the inductor manufacturing method disclosed herein is a method for manufacturing an inductor having a coil element embedded in a magnetic core and an electrode component connected to the coil element, comprising a coil element forming step, an electrode component pre-forming step, a connecting step, and a magnetic core forming step. The coil element forming step forms a coil element having a winding portion and a lead portion extending from the end of the winding portion. The electrode component pre-forming step forms an electrode component having: a side plate portion arranged along a predetermined direction; a first lead portion bent at one end of the side plate portion in the predetermined direction; and a connecting portion extending from the first lead portion and sequentially including a second riveting portion and a first riveting portion in order close to the first lead portion. The connecting step connects the lead portion and the connecting portion. The magnetic core forming step embeds the coil element, the first lead portion, and the connecting portion in a magnetic core. In the connecting step, the connecting portion and the lead portion are fused together by the following steps: that is, the lead portion is clamped and riveted by the second riveting portion and the first riveting portion. Then, a laser is irradiated onto the surface of the first riveting part along the direction from the surface of the first riveting part toward the surface of the second riveting part, forming a melt mark, i.e., a first melt mark, on the surface of the first riveting part by melting and solidifying the first riveting part, and forming a melt mark, i.e., a second melt mark, on the surface of the second riveting part by melting and solidifying the second riveting part, and then the connecting part and the lead wire part between the first melt mark and the second melt mark are melted and connected.

[0010] According to the inductor and the method for manufacturing the inductor disclosed herein, it is possible to suppress the reduction in the reliability of the inductor. Attached Figure Description

[0011] Figure 1 This is a schematic diagram showing an inductor in an embodiment. Figure 2This diagram illustrates the connection of the coil element and the electrode components in an embodiment. Figure 3 In the connection Figure 2 In the case of coil elements and electrode components, the diagram shows the lead portion of the coil element and the electrode components viewed from the end face side of the magnetic core. Figure 4A This is an external view of the inductor according to the implementation method. Figure 4B This is an external view of the inductor according to the implementation method. Figure 5A This is a diagram showing the coil element and electrode components of an inductor according to an embodiment. Figure 5B This is a diagram showing the coil element and electrode components of an inductor according to an embodiment. Figure 6 This is a diagram showing the coil element and electrode components of an inductor according to an embodiment. Figure 7 This is a diagram showing the coil element and electrode components of an inductor according to an embodiment. Figure 8 This is a diagram showing the connection portion of the inductor in an embodiment. Figure 9 This is a graph comparing the DCR characteristics of the inductor in the embodiment with those in the comparative example. Figure 10 This is a graph comparing the film foaming distance of the inductor in the embodiment with that of the comparative example. Figure 11 This is a graph showing the relationship between the bottom molten area of ​​the inductor in the embodiment and the ratio of the total molten area to the cross-sectional area of ​​the conductor. Figure 12 This is a graph comparing the DCR characteristics of the inductor of the embodiment with respect to the ratio of total molten area to conductor cross-sectional area with that of a comparative example. Figure 13 This is a graph comparing the DCR characteristics of the inductor of the embodiment with respect to the ratio of total molten area to conductor cross-sectional area with that of a comparative example. Figure 14 This is a diagram used to illustrate the crystal orientation analysis of the inductor in the embodiment. Figure 15 This is a flowchart illustrating a method for manufacturing an inductor according to an implementation method. Figure 16 This is a diagram showing a coil element formed through a coil element forming process. Figure 17 This is a diagram showing an electrode component formed through an electrode component preparation process. Figure 18 This diagram illustrates an example of the connection process between the coil element and the electrode component. Figure 19A This is a diagram illustrating the solder marks of an inductor in a modified embodiment of the present invention. Figure 19B This is a diagram illustrating the solder marks of an inductor in a modified embodiment of the implementation. Figure 19C This is a diagram illustrating the solder marks of an inductor in a modified embodiment of the implementation. Figure 19D This is a diagram illustrating the solder marks of an inductor in a modified embodiment of the present invention. Figure 19E This is a diagram illustrating the solder marks of an inductor in a modified embodiment of the implementation. Figure 19F This is a diagram illustrating the solder marks of an inductor in a modified embodiment of the present invention. Detailed Implementation

[0012] (Implementation Method) [Inductor Structure] The embodiments will now be described in detail with reference to the accompanying drawings. It should be noted that the embodiments described below represent specific examples of this disclosure. The numerical values, shapes, materials, constituent elements, arrangement positions of constituent elements, connection methods, steps, and order of steps shown in the following embodiments are examples and are not intended to limit this disclosure. Furthermore, constituent elements not described in the independent claims in the following embodiments will be described as optional constituent elements.

[0013] Furthermore, in this specification, terms such as parallelism indicating the relationship between elements, terms such as cuboid indicating the shape of elements, and numerical ranges are not merely expressions of a strict meaning, but also imply and include substantially equivalent ranges, such as expressions of a difference of about a few percent.

[0014] Furthermore, the figures are schematic diagrams that have been appropriately emphasized, omitted, or scaled to illustrate this disclosure, and are not necessarily strictly illustrative, sometimes differing from actual shapes, positional relationships, and scales. In each figure, structures substantially identical to those in other figures are labeled with the same reference numerals, and sometimes repeated descriptions are omitted or simplified.

[0015] Additionally, the X, Y, and Z axes, representing three mutually orthogonal directions, are shown in each figure. These axes, along with the axial direction along them, are used for illustration as needed. Furthermore, the axes are labeled for illustrative purposes only and do not limit the direction or orientation of the inductor.

[0016] Furthermore, in this specification, the terms "top surface" and "bottom surface" in the structure of the inductor do not refer to the absolute spatial identification of the top surface (the surface on the vertically upper side) and the bottom surface (the surface on the vertically lower side), but are used as terms defined by the relative positional relationship of the constituent elements of the inductor.

[0017] [Inductor Structure] Figure 1 This is a diagram showing the inductor 1 in the embodiment.

[0018] The inductor 1 in the embodiment is a passive element that stores the electrical energy flowing through the coil element as magnetic energy.

[0019] The inductor 1 of the embodiment includes: a magnetic core 10; a coil element 20 having a winding portion 21 and multiple lead portions 23, 24; and multiple electrode components 30 and 40 serving as terminal electrodes. Figure 1 In the diagram, the magnetic core 10 is represented by a dashed line. The magnetic core 10 is cuboid in shape and has a bottom surface 18, a top surface 19, end surfaces 13 and 14, and side surfaces 15 and 16.

[0020] One lead portion 23 of the coil element 20 is riveted and fixed to the connecting portion 34 of the electrode component 30, and the other lead portion 24 is riveted and fixed to the connecting portion 44 of the electrode component 40. Furthermore, one lead portion 23 of the coil element 20 is fused to the connecting portion 34, and the other lead portion 24 is fused to the connecting portion 44. In this fusion connection, first fusion marks 34ma and 44ma are formed on the connecting portions 34 and 44, respectively. The fusion connection between the lead portions 23 and 24 and the connecting portions 34 and 44 will be described later. Protrusions 33 and 43 are formed on the electrode components 30 and 40, respectively. In the height direction (Z-axis direction), the protrusions 33 and 43 protrude beyond the first leads 31 and 41. When connecting the electrode components 30 and 40 and the coil element 20, one lead portion 23 of the coil element 20 is riveted and fixed to the connecting portion 34 of the electrode component 30, and the other lead portion 24 is riveted and fixed to the connecting portion 44 of the electrode component 40. In order to ensure that the lead wires 23 and 24 contact the connecting portions 34 and 44 respectively before being riveted and fixed to the connecting portions 34 and 44, the coil element 20 is arranged such that the lead wires 23 and 24 are located on the protrusions 33 and 43 of the electrode components 30 and 40 respectively. Then, the coil element 20 is wound around the winding shaft 21c of the winding portion 21 (see below) Figure 2The coil element 20 rotates around a central point, causing the lead portions 23 and 24 to rotate and move, respectively, and come into contact with the connecting portions 34 and 44. In this embodiment, the first lead portions 31 and 41 are formed by bending the electrode components 30 and 40, respectively. To facilitate this bending process, first grooves 36 and 46 are formed. Without protrusions 33 and 43, cuts are formed with a depth equivalent to the first grooves 36 and 46, respectively. These cuts for bending the first lead portions 31 and 41 are at a height lower than the bent first lead portions 31 and 41 in the height direction. When the coil element 20 is rotated as described above to bring the lead portions 23 and 24 into contact with the connecting portions 34 and 44, such low-height cuts can easily cause the lead portions 23 and 24 to get stuck at the cuts. Therefore, in this embodiment, protrusions 33 and 43 that protrude beyond the first lead portions 31 and 41 in the height direction are provided. Further details are provided below.

[0021] Figure 2 This diagram illustrates the connection of the coil element 20 with the electrode components 30 and 40 in the embodiment. Figure 3 In the connection Figure 2 The diagram shows the lead portion 23 of the coil element 20 and the electrode components 30 and 40 viewed from the end face 13 side of the magnetic core 10. Figure 2 and Figure 3 The image shows the state before the connecting part 34 is riveted and fixed to the lead part 23.

[0022] In the inductor 1 of this embodiment, the coil element 20 is first arranged such that the lead portion 23 is located on the protrusion 33 of the electrode component 30. Then, by rotating the coil element 20 about the winding shaft 21c of the winding portion 21, the lead portion 23 is rotated and moved to be disposed on the connecting portion 34. In this embodiment, the lead portion 23 is disposed on the protrusion 33, which is higher than the first lead-out portion 31. Therefore, when the lead portion 23 is rotated, it moves smoothly on the protrusion 33 and the first lead-out portion 31 and is disposed on the connecting portion 34. As a result, damage to the lead portion 23 can be suppressed, and the reliability of the inductor 1 can be suppressed. In addition, the lead portion 23 can be prevented from getting stuck on the electrode component 30, thus reducing production efficiency can be suppressed.

[0023] Figure 4A and Figure 4B This is an external view of the inductor 1 according to the embodiment. Figure 5A and Figure 5B This is a diagram showing the coil element 20 and electrode components 30 and 40 of the inductor 1 according to the embodiment.

[0024] Figure 4A and Figure 4BThese are three-dimensional views of inductor 1 viewed from different angles. Figure 5A and Figure 5B These are perspective views showing the coil element 20 and electrode components 30 and 40 viewed from different angles. Figure 5A and Figure 5B In the diagram, the outline of the magnetic core 10 is represented by dashed lines.

[0025] Figure 6 and Figure 7 This is a diagram showing the coil element 20 and electrode components 30 and 40 of the inductor 1 according to an embodiment. Figure 6 and Figure 7 The illustration of magnetic core 10 is omitted in the text. Additionally, Figure 8 This is a diagram showing the connection portion 34 of the inductor 1 according to the embodiment. Figure 8 In (a) and (b), attention is paid to the vicinity of the connecting part 34, and the following is shown along... Figure 6 The cross-sectional view of lines VIIIA~VIIIA and VIIIB~VIIIB shown.

[0026] Figure 4A , Figure 4B , Figure 5A as well as Figure 5B The inductor 1 shown includes: a magnetic core 10; a coil element 20 having a winding portion 21 and multiple lead portions 23, 24; and multiple electrode components 30 and 40 serving as terminal electrodes. The general shape of the inductor 1 is determined, for example, by the shape of the magnetic core 10, which is a calendered magnetic core. Furthermore, the magnetic core 10 can be molded into an arbitrary shape. That is, an inductor 1 of arbitrary shape is formed based on the shape of the magnetic core 10 during molding. In this embodiment, the magnetic core 10 is cuboid in shape, for example, with a dimension of 10 mm in the X-axis direction, 10 mm in the Y-axis direction, and 5 mm in the Z-axis direction.

[0027] The magnetic core 10 is the outer casing of the inductor 1, covering the entire coil element 20 and a portion of the electrode components 30 and 40. The magnetic core 10 contains a magnetic material, such as a pressed powder core formed from a mixture of metallic magnetic powder and resin material. The magnetic core 10 can be made using a magnetic material. Ferrite or other magnetic materials can be used. The metallic magnetic powder uses particulate materials with a specified elemental composition, such as Fe-Si-Al, Fe-Si, Fe-Si-Cr, or Fe-Si-Cr-B systems. Furthermore, the resin material is selected from materials such as siloxane resins that can maintain a certain shape by insulating and binding the particles of the metallic magnetic powder together.

[0028] The magnetic core 10 has a bottom surface 18, a top surface 19 facing away from the bottom surface 18, and two end surfaces 13 and 14 connecting the bottom surface 18 and the top surface 19. Additionally, the magnetic core 10 has two side surfaces 15 and 16 connecting the bottom surface 18 and the top surface 19 and connecting to the end surfaces 13 and 14. Viewed from a direction perpendicular to the top surface 19 (Z-axis direction), the magnetic core 10 is quadrilateral. Viewed from a direction perpendicular to the top surface 19, the magnetic core 10 can be rectangular or square. The bottom surface 18 and the top surface 19 face away from each other in the Z-axis direction, the end surfaces 13 and 14 face away from each other in the Y-axis direction, and the side surfaces 15 and 16 face away from each other in the X-axis direction.

[0029] The bottom surface 18, top surface 19, end surfaces 13 and 14, and side surfaces 15 and 16 each have a flat plane. The bottom surface 18 and top surface 19 are arranged in the Z-axis direction and are parallel to each other. The end surfaces 13 and 14 are arranged in the Y-axis direction. The side surfaces 15 and 16 are arranged in the X-axis direction and are parallel to each other. In this example, the end surfaces 13 and 14 are inclined inward, and their distance from each other decreases as they move from the bottom surface 18 toward the top surface 19.

[0030] Furthermore, the bottom surface 18 and top surface 19 intersect with the end surface 13 (or 14) when extended in a plane. The bottom surface 18 and top surface 19 intersect with the side surface 15 (or 16) when extended in a plane, specifically, they are orthogonal. The end surface 13 (or 14) intersects with the side surface 15 (or 16) when extended in a plane.

[0031] Two bottom surface recesses 18a are formed on the bottom surface 18 of the magnetic core 10 (see reference). Figure 1 The bottom plate portion 38 of the electrode component 30 is disposed in one of the two bottom surface recesses 18a, and the bottom plate portion 48 of the electrode component 40 is disposed in the other bottom surface recess 18a.

[0032] The coil element 20 is disposed inside the magnetic core 10. That is, the coil element 20 is entirely embedded in the magnetic core 10.

[0033] The coil element 20 is formed, for example, by a single wire. For example, the wire is a round wire with a cross-sectional diameter of 0.5 mm. Furthermore, the wire diameter is appropriately selected from a range of 0.2 mm to 1 mm. The wire is, for example, composed of a metal wire and an insulating coating covering the metal wire. The metal wire is made of a metallic material selected from metals such as aluminum, copper, silver, and gold, alloys containing one or more of these metals, and materials formed from metals or alloys and other substances. Specifically, the wire is, for example, a copper wire covered with an insulating coating.

[0034] The coil element 20 has a winding portion 21 with a wire wound around it and multiple lead portions 23 and 24 extending from the ends of the winding portion 21. In this example, the coil element 20 consists of one winding portion 21 and two lead portions 23 and 24. The winding portion 21 and the lead portions 23 and 24 are, for example, additional names for various parts formed by processing a wire made from the same raw material. The coil element 20 is arranged within the magnetic core 10 with the winding axis 21c of the winding portion 21 perpendicular to the bottom surface 18 and the top surface 19.

[0035] The winding section 21 is composed of wound wire and serves as the functional part of the coil. The winding section 21 consists of an inner circumferential coil and an outer circumferential coil connected to the inner circumferential coil. Both the inner and outer circumferential coils have two turns. Furthermore, the number of turns in the winding section 21 is not particularly limited and is appropriately selected based on constraints such as the required performance of the inductor 1 and the size of the magnetic core 10. Lead sections 23 and 24 are connected to both ends of the winding section 21. Specifically, lead section 23 is connected to the end of the inner circumferential coil, and lead section 24 is connected to the end of the outer circumferential coil.

[0036] Lead sections 23 and 24 are composed of straight wires. Lead sections 23 and 24 are arranged along a diagonal of the top surface 19 of a quadrilateral shape. Lead sections 23 and 24 are led out from the end of the winding section 21 toward the surface of the magnetic core 10 and are interrupted before reaching the surface of the magnetic core 10. The distance from the end of the lead section 23 to the end of the lead section 24 is longer than the distance from the end face 13 to the end face 14 (or the distance from the protrusion 33 to the protrusion 43), but shorter than the length of the diagonal of the magnetic core 10.

[0037] Viewed from a direction perpendicular to the top surface 19 (Z-axis direction), one lead portion 23 is disposed at the corner 10r of the magnetic core 10 where the end face 13 intersects with the side face 15. Viewed from a direction perpendicular to the top surface 19, another lead portion 24 is disposed at the corner 10r of the magnetic core 10 where the end face 14 intersects with the side face 16. That is, lead portions 23 and 24 are respectively disposed at opposite corners 10r on the diagonals of the quadrilateral top surface 19. By distributing lead portions 23 and 24 at the corners 10r of the magnetic core 10, the volume of the magnetic core 10 can be utilized effectively, and the overlap characteristics of the inductor 1 can be improved.

[0038] Furthermore, when viewed from a direction perpendicular to end face 13, lead portion 23 is positioned closer to the top surface 19 than the center of end face 13; specifically, it is positioned closer to the top surface 19 than the first lead portion 31 described later. When viewed from a direction perpendicular to end face 14, lead portion 24 is positioned closer to the top surface 19 than the center of end face 14; specifically, it is positioned closer to the top surface 19 than the first lead portion 41 described later.

[0039] Lead portions 23 and 24 have their insulating coating removed in a manner that allows them to conduct electricity with electrode components 30 and 40, respectively. Lead portion 23 is riveted to the connecting portion 34 of electrode component 30, and then connected and fixed to electrode component 30 by welding. Lead portion 24 is riveted to the connecting portion 44 of electrode component 40, and then connected and fixed to electrode component 40 by welding.

[0040] Electrode component 30 and lead portion 23, and electrode component 40 and lead portion 24 have shapes and positional relationships that are symmetrical about the winding shaft 21c at a point of 180°. Hereinafter, electrode component 30 of electrode components 30 and 40 will be used as an example for explanation.

[0041] like Figure 5A and Figure 5B As shown, the electrode component 30 has a side plate portion 35 and a bottom plate portion 38. In addition, the electrode component 30 has a first lead-out portion 31, a connecting portion 34, a protrusion 33, a second lead-out portion 32, a first groove portion 36, and a second groove portion 37.

[0042] Electrode component 30 is formed, for example, from a metal plate. The metal plate is made of a metal material selected from metals such as aluminum, copper, silver, and gold, alloys containing one or more of these metals, and materials formed from metals or alloys and other substances. The thickness of the metal plate is, for example, 0.15 mm. Side plate portion 35, first lead-out portion 31 and connecting portion 34, second lead-out portion 32, protrusion portion 33, and base plate portion 38 are, for example, additional names for various parts formed by processing a sheet of material made of the same material. First groove portion 36 and second groove portion 37 are respectively slits for facilitating bending processing of the first lead-out portion 31 and the second lead-out portion 32.

[0043] A side plate portion 35 is disposed on the outer side of the magnetic core 10 along the end face 13 of the magnetic core 10. The side plate portion 35 is plate-shaped and contacts the end face 13. In a direction perpendicular to the top surface 19, the length of the side plate portion 35 is shorter than the length (height) of the end face 13. The end portion 35a on the top surface 19 side of the side plate portion 35 is located on the bottom surface 18 side of the top surface 19, and the end portion 35b on the bottom surface 18 side of the side plate portion 35 is located on the bottom surface 18 side of the bottom surface 18 side of the side plate portion 35 and at approximately the same height as the end portion 35a.

[0044] The base plate portion 38 is connected to the end portion 35b on the bottom surface 18 side of the side plate portion 35, and extends from the end portion 35b on the bottom surface 18 side and along the bottom surface 18. Specifically, the base plate portion 38 is bent starting from the end portion 35b on the bottom surface 18 side of the side plate portion 35, and is configured such that at least a portion of it enters the bottom surface recess 18a.

[0045] The outer surfaces of the side plate portion 35 and the bottom plate portion 38 are exposed and not embedded in the magnetic core 10. The side plate portion 35 and the bottom plate portion 38 are the parts that are joined to the circuit board using solder or the like when the inductor 1 is mounted on the circuit board.

[0046] The first lead-out portion 31, the connecting portion 34, and the second lead-out portion 32 are embedded in the magnetic core 10. In this embodiment, the first lead-out portion 31, the connecting portion 34, and the second lead-out portion 32 are embedded in the magnetic core 10, thereby being configured such that the electrode component 30 will not fall off the magnetic core 10.

[0047] The first lead-out portion 31 is connected to the end portion 35a on the top surface 19 side of the side plate portion 35, and extends from the end portion 35a on the top surface 19 side into the interior of the magnetic core 10. The first lead-out portion 31 is formed by bending from the end portion 35a on the top surface 19 side of the side plate portion 35. The first lead-out portion 31 is arranged parallel to the top surface 19.

[0048] The connecting portion 34 is connected to the first lead-out portion 31 and is connected to the lead portion 23 inside the magnetic core 10. The connecting portion 34 is riveted and fixed in such a way that it is wound around and covers more than half a circumference of the outer periphery of the lead portion 23. In addition, the connecting portion 34 is also joined to the lead portion 23 by laser welding.

[0049] Here, the connecting portion 34 includes the second riveting portion 34b in sequence from the first lead-out portion 31 (see reference). Figure 8 ) and the first riveting part 34a (refer to Figure 8 The second riveting part 34b clamps the lead wire part 23 from the bottom surface 18 side, and the first riveting part 34a is riveted together with the lead wire part 23 in such a way that it clamps the lead wire part 23 from the top surface 19 side. Furthermore, as... Figure 6 As shown, a first melt mark 34ma is formed at the first riveting portion 34a on the top surface 19 side, accompanied by laser welding. Additionally, as... Figure 7 As shown, a second fusion mark 34mb is formed on the second riveting portion 34b on the bottom surface 18 by laser welding. Laser welding is performed by irradiating a laser only from the top surface 19 side. Between the first fusion mark 34ma and the second fusion mark 34mb, a portion of the connecting portion 34 and a portion of the lead portion 23 are melted and solidified (melt-solidification) through welding to form a welded portion 34m. The welded portion 34m is both a part of the connecting portion 34 and a part of the lead portion 23.

[0050] The second lead-out portion 32 is connected to the end portion 35a on the top surface 19 side of the side plate portion 35, and extends from the end portion 35a on the top surface 19 side into the interior of the magnetic core 10. The second lead-out portion 32 is formed by bending from the end portion 35a on the top surface 19 side of the side plate portion 35. The second lead-out portion 32 is arranged parallel to the top surface 19. No connecting portion is provided in the second lead-out portion 32, but a through hole 32h is formed to strengthen anti-detachment.

[0051] The protrusion 33 is connected to the end portion 35a on the top surface 19 side of the side plate portion 35, and protrudes further towards the top surface 19 side from the end portion 35a on the top surface 19 side. The protrusion 33 is disposed along the end face 13, and the outer surface of the protrusion 33 is not embedded in the magnetic core 10. Alternatively, for example, the protrusion 33 may be slightly bent towards the center 10c side of the magnetic core 10 from the end portion 35a on the top surface 19 side of the side plate portion 35, and the front end 33e of the protrusion 33 may be embedded in the magnetic core 10. In addition, at least part or all of the metal material plate with a thickness of 0.15 mm may be embedded and fixed in the magnetic core 10 for the side plate portion 35 and the protrusion 33, while the bottom plate portion 38 is not embedded in the magnetic core 10. By embedding and fixing the side plate portion 35 and the protrusion 33 to the magnetic core 10, vibration resistance can be ensured, and since the bottom plate portion 38 is not fixed to the magnetic core 10, thermal cycling resistance can be improved.

[0052] At the end 35a on the top surface 19 side of the side plate portion 35, a first groove 36 is provided between the first lead-out portion 31 and the protrusion 33. The first groove 36 is a groove that travels in the thickness direction of the side plate portion 35. The width of the first groove 36 is preferably smaller than the width of the cross-section of the wire forming the coil element 20. For example, the width of the first groove 36 is 0.2 mm or more and 0.4 mm or less.

[0053] At the end 35a on the top surface 19 side of the side plate portion 35, a second groove portion 37 is provided between the second lead-out portion 32 and the protrusion portion 33. The second groove portion 37 is a groove that travels in the thickness direction of the side plate portion 35. The groove width of the second groove portion 37 is preferably the same as the groove width of the first groove portion 36.

[0054] Thus, at the end 35a on the top surface 19 side of the side plate portion 35, a protrusion 33, a first groove 36, a second groove 37, a first lead-out portion 31, and a second lead-out portion 32 are provided. These protrusions 33, first grooves 36, second grooves 37, first lead-out portions 31, and second lead-out portions 32 are provided in different areas of the end 35a on the top surface 19 side of the side plate portion 35.

[0055] Viewed from a direction perpendicular to the top surface 19 (Z-axis direction), the protrusion 33 is positioned at a point overlapping with a line 10cL passing through the center 10c of the magnetic core 10 and perpendicular to the end face 13 (see reference). Figure 4AIn other words, the protrusion 33 is disposed at the center of the side plate portion 35 in a direction perpendicular to the side surface 15. A first groove 36 and a second groove 37 are provided on both outer sides of the protrusion 33. That is, viewed from the protrusion 33, the first groove 36 is located on the side surface 15. The first extension portion 31 is located further to the side surface 15 than the first groove 36. Viewed from the protrusion 33, the second groove 37 is located on the side surface 16. The second extension portion 32 is located further to the side surface 16 than the second groove 37.

[0056] In this embodiment, when viewed from a direction perpendicular to the end face 13, the front end 33e of the protrusion 33 is located on the side closer to the top surface 19 than the first lead-out portion 31. Furthermore, when comparing the position coordinates in a direction perpendicular to the top surface 19 (Z-axis direction), the front end 33e of the protrusion 33 is located on the side closer to the top surface 19 than the guide surface 31g of the first lead-out portion 31, and on the side closer to the bottom surface 18 than the edge end 34e of the connecting portion 34. The dimension by which the protrusion 33 protrudes further towards the top surface 19 than the first lead-out portion 31 is preferably smaller than the height dimension of the cross-section of the wire forming the coil element 20. The protrusion height by which the protrusion 33 protrudes further towards the top surface 19 than the first lead-out portion 31 is, for example, 0.1 mm or more and 0.4 mm or less. Furthermore, the guide surface 31g is the surface that abuts against the lower end of the lead portion 23 when the lead portion 23 slides on the first lead-out portion 31 and moves towards the connecting portion 34.

[0057] In this way, by positioning the protrusion 33 with its front end 33e located on the side closer to the top surface 19 than the first lead-out portion 31, for example, when the lead portion 23 of the coil element 20 is placed on the front end 33e of the protrusion 33 and the coil element 20 is rotated to move the lead portion 23, the lead portion 23 will not get stuck on the electrode member 30, allowing the lead portion 23 to move smoothly to the connection portion 34. This suppresses damage to the lead portion 23 of the coil element 20 and prevents a decrease in the reliability of the inductor 1. Furthermore, the lead portion 23 can be reliably positioned on the connection portion 34, thus improving the connection reliability between the lead portion 23 and the connection portion 34. Additionally, the improved positional accuracy of the lead portion 23 and the connection portion 34 relative to the magnetic core 10 enhances the vibration resistance of the inductor 1.

[0058] Here, we examine whether the fusion connection between the connecting portion 34 and the lead portion 23 is performed using a laser from the top surface 19 or using a laser from the bottom surface 18. Here, we will use the case where the fusion connection between the connecting portion 34 and the lead portion 23 is performed using a laser from the top surface 19 as an example (described later). Figures 9-13(The center is a hollow circular mark), and the case of fusion bonding between the connecting part 34 and the lead part 23 by laser from the bottom surface 18 side is used as a comparative example (described later). Figures 9-13 (The center is marked with a black circle). However, the following description does not apply if the first riveting portion 34a on the top surface 19 and the second riveting portion 34b on the bottom surface 18 are arranged in order from near to far from the first lead-out portion 31. For the fusion connection between the connecting portion 34 and the lead portion 23, whether the connection is made by a laser from the top surface 19 or the bottom surface 18, it is important to perform the connection from the surface of the riveting portion furthest from the first lead-out portion 31. In other words, for the fusion connection between the connecting portion 34 and the lead portion 23, whether the connection is made by a laser from the top surface 19 or the bottom surface 18, it is important to perform the connection from the surface of the riveting portion closest to the edge 34e.

[0059] Figure 9 This is a graph comparing the DCR (DC resistance) characteristics of the inductor in the embodiment with those of the comparative example. Figure 10 This is a graph comparing the film foaming distance of the inductor in the embodiment with that of the comparative example. Figure 11 This is a graph showing the relationship between the bottom molten area of ​​the inductor in the embodiment and the ratio of the total molten area to the cross-sectional area of ​​the conductor. Figure 12 This is a graph comparing the DCR characteristics of the inductor of the embodiment with respect to the ratio of total molten area to conductor cross-sectional area with that of a comparative example. Figure 13 This is a graph comparing the DCR characteristics of the inductor of the embodiment with respect to the ratio of total molten area to conductor cross-sectional area with that of a comparative example. Figure 14 This is a diagram used to illustrate the crystal orientation analysis of the inductor in the embodiment.

[0060] like Figure 9 As shown, compared to the comparative example, the embodiment exhibits a low DCR (DC resistance value) relative to the laser output in the region where the laser output is low (less than 1250W). Since a lower DCR value results in better characteristics of the inductor 1, the embodiment with a low DCR value is more advantageous than the comparative example when performing the fusion connection between the connection portion 34 and the lead portion 23 using a low-output laser. For example, the insulation coating of the wire may deteriorate due to the heat during the welding connection, so it is useful to achieve a low DCR value with a low-output laser.

[0061] For example, such as Figure 10As shown, in regions where the laser output is low (less than 1250W), the foaming distance of the coating in the embodiment (the distance from the foamed (deteriorated) coating to the welded portion 34m) is shorter than that in the comparative example. In other words, it can be said that compared to the fusion bonding of the connector 34 and the lead portion 23 via a laser from the top surface 19 side, it is more difficult to foam the insulating coating of the conductor via a laser from the bottom surface 18 side.

[0062] This can be explained as follows. First, when laser light is irradiated from the top surface 19, the laser irradiates the surface of the first riveting portion 34a, causing it to heat up and melt in the order of the first riveting portion 34a, the lead wire portion 23, and the second riveting portion 34b. The first riveting portion 34a is close to the edge 34e, making it difficult for heat to reach other parts of the connecting portion 34, thus the first riveting portion 34a is heated efficiently. Therefore, heat easily reaches the lead wire portion 23 from the first riveting portion 34a, and the lead wire portion 23 is also effectively heated. Here, although the heat from the lead wire portion 23 to the winding portion 21 causes foaming of the insulating coating, the heat from the lead wire portion 23 is distributed to the winding portion 21 and the second riveting portion 34b because the second riveting portion 34b, where the heat has not yet reached, is located nearby. In particular, the second riveting portion 34b is thermally connected to other parts of the electrode component 30, making it difficult to heat, thus more heat is distributed to the second riveting portion 34b. As a result, less heat is applied to the winding section 21 before the weld section 34m is formed.

[0063] On the other hand, when laser light is irradiated from the bottom surface 18, the laser light irradiates the surface of the second riveting portion 34b, causing it to heat up and melt in the order of the second riveting portion 34b, the lead portion 23, and the first riveting portion 34a. The second riveting portion 34b is thermally connected to other parts of the electrode component 30, so the heat reaches other parts of the connecting portion 34, resulting in inefficient heating. Furthermore, heat travels from the second riveting portion 34b to the lead portion 23, which is used to melt the lead portion 23 and distribute it to the winding portion 21 and the first riveting portion 34a. The first riveting portion 34a is located near the edge 34e, and is heated efficiently. As a result, more heat is applied to the winding portion 21 before the weld portion 34m is formed.

[0064] Thus, when laser light is irradiated from either the top surface 19 or the bottom surface 18, it can be said that irradiation from the surface of the riveted portion (here, the top surface 19) near the edge 34e is more effective in suppressing the degradation of the inductor 1. Here, the first riveted portion 34a melts before the second riveted portion 34b, therefore the area of ​​the melt mark formed on its surface, i.e., the first melt mark 34ma, is larger than the area of ​​the melt mark formed on the surface on the bottom surface 18, i.e., the second melt mark 34mb. Figures 11-13An appropriate value is defined for the area of ​​such a melt line.

[0065] like Figure 11 As shown, when the sum of the surface areas of the first fusion mark 34ma and the second fusion mark 34mb (total fusion area) exceeds 50% of the cross-sectional area of ​​the conductor (here, the cross-sectional area of ​​the wire without deformation such as riveting), the surface area of ​​the second fusion mark 34mb becomes greater than 0. That is, a weld portion 34m that reaches the surface of the second riveting portion 34b can be formed. However, even if it does not reach the surface of the second riveting portion 34b, as long as the weld portion 34m can be formed into the interior of the second riveting portion 34b, an electrical connection between the connecting portion 34 and the lead portion 23 can be achieved, and therefore the total fusion area relative to the cross-sectional area of ​​the conductor can, for example, be 20% or more. This can also be said to be due to Figure 12 The DCR value is within the standard value (8.48mΩ). In practice, it is necessary to manufacture inductor 1 within a safe range that takes into account manufacturing errors, etc. Therefore, for example, as... Figure 13 As shown, the target is to achieve a value within +2% when standardized based on 8.2 mΩ. For this benchmark, the total molten area relative to the conductor cross-sectional area is preferably 50% or more. Furthermore, this specific value can vary depending on the wire cross-sectional area and material, and can therefore be appropriately determined through rules of thumb or prior experiments.

[0066] The following is further use Figure 14 An appropriate value is defined for the crystallization state inside the 34m weld section. Figure 14 In the middle, it is shown that the relationship with Figure 8 The analysis results of crystal orientation analysis were performed on the cross-section of the lead portion 23 and the connecting portion 34, which were actually fused together from the same viewpoint (a). Specifically, the inverse pole figure orientation diagram of electron backscatter diffraction (EBSD) is shown. In the figure, regions with different contrast represent particles with different crystal orientations. In addition, the weld portion 34m is represented by a hollow thick line in the figure. Furthermore, the regions a, b, c, d, g, h, i, and k used for the analysis of each region are represented by dashed lines (regions a, b, and c are the weld portion 34m).

[0067] From the perspective of ensuring the strength of the welded section 34m, the area average diameter D of the crystalline structure in the welded section 34m is... MA There exists a suitable range, for example, it can be above 5μm and below 100μm. As an example, for welding and forming of the magnetic core 10, three different conditions were set within the standard value, and the area-average diameter D was calculated. MAThe evaluation was conducted using (μm). Under standard welding conditions (specifically, welding conditions where the total molten area is 112% of the conductor cross-sectional area and the conductor is embedded before the magnetic core 10), as shown in Table 1, the area-average diameter D... MA The micrometers in regions a, b, c, d, g, h, i, and k are 13.6 μm, 11.2 μm, 21 μm, 6.3 μm, 6.5 μm, 8.6 μm, 8 μm, and 6.3 μm, respectively.

[0068] [Table 1]

[0069] Under standard welding and forming conditions (specifically, welding conditions where the total molten area is 112% of the conductor cross-sectional area and the portion of the metal magnetic powder with the lowest density during the forming of the magnetic core 10 coincides with the positions of the lead portions 23 and 24), as shown in Table 2, the area-average diameter D MA The micrometers in regions a, b, c, d, g, h, i, and k are 33.2 μm, 23.1 μm, 30.8 μm, NA, 5.8 μm, 7.1 μm, NA, and 6.2 μm, respectively. It should be noted that NA indicates that the micrometers cannot be measured.

[0070] [Table 2]

[0071] Under the conditions of welding within the standard value and forming within the upper limit of the standard value (specifically, welding conditions where the total molten area is 89% of the conductor cross-sectional area and the part with the lowest density of the metal magnetic powder moves 0.28 mm towards the bottom surface 18 relative to the positions of the lead portions 23 and 24 during the forming of the magnetic core 10), as shown in Table 3, the area-average diameter D MA The micrometers in regions a, b, c, d, g, h, i, and k are 19.2 μm, 23.7 μm, 26 μm, NA, 8.8 μm, 7.6 μm, NA, and 6.8 μm, respectively.

[0072] [Table 3]

[0073] Regarding the average diameter D of the area MA The thickness is 11μm~34μm in the welded area (regions a, b, c) and 5μm~9μm in the non-welded area (regions d, g, h, i, k).

[0074] In addition, the crystal structure D MAThe calculation formula is shown in equation (1) below. Wherein, S represents the grain area, which is measured using grain size analysis software, and DH represents the Heywood diameter calculated from the grain area using grain size analysis software.

[0075]

[0076] From the perspective of reducing crystallization strain and ensuring the strength of the weld 34m, the area average aspect ratio AR of the crystalline structure in the weld 34m is... MA The smaller the better, for example, below 7. As an example, for welding and forming, three different conditions were set within the standard value to calculate the area average aspect ratio (AR). MA Evaluation was conducted. Under standard welding conditions (specifically, welding conditions where the total molten area is 112% of the conductor cross-sectional area and the weld is embedded before the magnetic core 10), as shown in Table 4, the area-average aspect ratio AR was... MA The values ​​in regions a, b, c, d, g, h, i, and k are 1.98, 1.80, 1.90, 1.84, 1.88, 2.39, 2.01, and 1.87, respectively.

[0077] [Table 4]

[0078] Under standard welding and forming conditions (specifically, welding conditions where the total molten area is 112% of the conductor cross-sectional area and the portion of the metal magnetic powder with the lowest density during the forming of the magnetic core 10 coincides with the positions of the lead portions 23 and 24), as shown in Table 5, the area-to-width ratio AR MA The values ​​in regions a, b, c, d, g, h, i, and k are 1.72, 2.20, 2.19, NA, 1.83, 2.24, NA, and 1.85, respectively.

[0079] [Table 5]

[0080] Under the conditions where welding and forming are within the upper limit of standard values ​​(specifically, welding conditions where the total molten area is 89% of the conductor cross-sectional area and the portion with the lowest density of the metal magnetic powder in the forming of the magnetic core 10 moves 0.28 mm towards the bottom surface 18 relative to the positions of the lead portions 23 and 24), as shown in Table 6, the area-to-width ratio AR MA The values ​​in regions a, b, c, d, g, h, i, and k are 2.02, 3.49, 2.41, NA, 1.93, 1.95, NA, and 2.16, respectively.

[0081] [Table 6]

[0082] Regarding the average aspect ratio AR MA The value is 1.8~3.5 in the welded part 34m (areas a, b, c) and 1.8~2.4 in the non-welded part (areas d, g, h, i, k).

[0083] In addition, the average aspect ratio of the area AR MA The calculation formula is shown in equation (2) below. Wherein, AR represents the ratio of the maximum Ferret diameter to the minimum Ferret diameter calculated using particle size analysis software.

[0084]

[0085] In the above description, electrode component 30 of electrode components 30 and 40 was used as an example, but the same can be said for electrode component 40. In this case, the structure with the symbols replaced as follows holds true.

[0086] For example, replace the electrode component 30 with the electrode component 40, replace the first lead-out portion 31 with the first lead-out portion 41, replace the guide surface 31g with the guide surface 41g, replace the second lead-out portion 32 with the second lead-out portion 42, replace the through hole 32h with the through hole 42h, replace the protrusion 33 with the protrusion 43, replace the front end 33e with the front end 43e, replace the connecting portion 34 with the connecting portion 44, replace the first melt mark 34ma with the first melt mark 44ma, and replace the second melt mark 34m b is replaced with the second melt mark 44mb, edge 34e is replaced with edge 44e, side plate 35 is replaced with side plate 45, end 35a is replaced with end 45a, end 35b is replaced with end 45b, first groove 36 is replaced with first groove 46, second groove 37 is replaced with second groove 47, bottom plate 38 is replaced with bottom plate 48, and end face 13 is replaced with end face 14, side face 15 is replaced with side face 16, and lead wire 23 is replaced with lead wire 24, and so on.

[0087] [Inductor Manufacturing Method] Reference Figures 15-18 The manufacturing method of the inductor 1 described above will be explained.

[0088] Figure 15 This is a flowchart illustrating the manufacturing method of inductor 1 according to the embodiment.

[0089] The manufacturing method of inductor 1 includes a coil element forming process S10, an electrode component pre-forming process S20, a connection process S30, and a magnetic core forming process S40. Additionally, the manufacturing method of inductor 1 also includes a base plate forming process S50.

[0090] Figure 16 This is a diagram showing the coil element 20 formed through the coil element forming process S10.

[0091] In the coil element forming process S10, a coil element 20 is formed having a winding portion 21 with a wire wound around it and lead portions 23 and 24 extending from the end of the winding portion 21. In at least a portion of the lead portions 23 and 24, the insulating film of the wire is removed.

[0092] Figure 17 This is a diagram showing electrode components 30 and 40 formed through the electrode component preparation forming process S20. The diagram shows an example where electrode components 30 and 40 are formed from a hoop material, but this is not the only example; electrode components 30 and 40 can also be fixed to a conveying fixture by means of locating pins or the like.

[0093] In the electrode component preparation forming process S20, electrode components 30 and 40 are prepared and formed.

[0094] In this process S20, an electrode component 30 is prepared to be formed, having a side plate portion 35 arranged along a predetermined direction, a first lead-out portion 31 bent at one end 35a in the predetermined direction of the side plate portion 35, a connecting portion 34 extending from the first lead-out portion 31, and a protrusion 33 protruding in the predetermined direction from one end 35a in the predetermined direction of the side plate portion 35.

[0095] The electrode component 30 to be formed is in its state before riveting and forming, and an opening for inserting the lead wire 23 in a subsequent process is provided in the connecting part 34. Furthermore, the electrode component 30 to be formed is in its state before the base plate 38 is bent and formed, and the lower part of the side plate 35 is called the foot 38a. In addition, the specified direction refers to the direction in which the foot 38a extends in a straight line.

[0096] In addition, in this process S20, an electrode component 40 is prepared to be formed, which has a side plate portion 45 arranged along a predetermined direction, a first lead-out portion 41 bent at one end 45a in the predetermined direction of the side plate portion 45, a connecting portion 44 extending from the first lead-out portion 41, and a protrusion 43 protruding from one end 45a in the predetermined direction of the side plate portion 45 in the predetermined direction.

[0097] The electrode component 40 to be formed is in its state before riveting and forming, and an opening for inserting the lead wire 24 in a subsequent process is provided in the connecting part 44. Furthermore, the electrode component 40 to be formed is in its state before the base plate part 48 is bent and formed, and the lower part of the side plate part 45 is called the foot 48a. In addition, the specified direction refers to the direction in which the foot 48a extends in a straight line.

[0098] Figure 18 This is a diagram illustrating an example of the connection process S30 between the coil element 20 and the electrode components 30 and 40.

[0099] In the connection process S30, the lead wire 23 is connected to the connection part 34, and the lead wire 24 is connected to the connection part 44.

[0100] Specifically, such as Figure 18 As shown in (a), the winding portion 21 of the coil element 20 is inserted into the support column 61 of the conveying fixture, the lead portion 23 is disposed on the front end 33e of the protrusion 33, and the lead portion 24 is disposed on the front end 43e of the protrusion 43.

[0101] Next, as Figure 18 As shown in (b), the winding portion 21, lead portion 23, and 24 of the coil element 20 are rotated about the winding shaft 21c. In this figure, the coil element 20 is rotated by pressing the rotating lead portion 23 with the rotating member 62. Thus, as... Figure 18 As shown in (c), the lead portion 23 is moved from its position on the protrusion 33 to the connecting portion 34 via the first lead-out portion 31. Simultaneously, the lead portion 24 is moved from its position on the protrusion 43 to the connecting portion 44 via the first lead-out portion 41 (not shown). Specifically, the lead portion 23 is inserted into the opening of the connecting portion 34 while contacting the protrusion 33 and the first lead-out portion 31, and the lead portion 24 is inserted into the opening of the connecting portion 44 while contacting the protrusion 43 and the first lead-out portion 41.

[0102] Next, as Figure 18 As shown in (d), the lead wire portion 23 and the connecting portion 34 are riveted together using a riveting jig (not shown). Specifically, the lead wire portion 23 is clamped and riveted using the second riveting portion 34b and the first riveting portion 34a. Similarly, the connecting portion 44 is riveted to the lead wire portion 24 using a riveting jig. The lead wire portion 23 and the connecting portion 34, as well as the lead wire portion 24 and the connecting portion 44, are laser welded together after riveting. Specifically, as shown in (d), Figure 18 As shown by the hollow arrow in (d), a laser is irradiated onto the surface of the first riveting part 34a in a direction from the surface of the first riveting part 34a toward the surface of the second riveting part 34b, as shown in the image. Figures 6-8As shown, a melt mark 34ma is formed on the surface of the first riveting part 34a by melting and solidifying the first riveting part 34a, and a melt mark 34mb is formed on the surface of the second riveting part 34b by melting and solidifying the second riveting part 34b (see reference). Figure 8 A weld portion 34m is formed between the first melt line 34ma and the second melt line 34mb, which solidifies after melting. The connecting portion 34 between the first melt line 34ma and the second melt line 34mb is then fused together with the lead portion 23. The lead portion 24 and the connecting portion 44 are also fused together in the same way.

[0103] In the core forming process S40, the coil element 20, the first leads 31 and 41, and the connecting parts 34 and 44 are embedded in the magnetic core 10. Alternatively, a portion of the thickness direction of the side plate parts 35 and 45 and the protrusions 33 and 43 may be embedded in the magnetic core 10. This process S40 is performed by placing the coil element 20, the first leads 31 and 41, and the connecting parts 34 and 44 into a molding die and pressing the mixture of materials that form the magnetic core 10 into shape. During this forming process, a bottom surface recess 18a is formed on the bottom surface 18 of the magnetic core 10 at a position overlapping with the bottom plate part 38.

[0104] In the base plate forming process S50, the base plate 38 and 48 are formed by bending the lower parts of the side plate parts 35 and 45. The front ends of the base plate parts 38 and 48 are bent into the bottom surface recess 18a.

[0105] According to this manufacturing method, when the lead portions 23 and 24 are rotated, they smoothly move on the protrusions 33 and 43 and the first lead-out portions 31 and 41, respectively, and are positioned on the connecting portions 34 and 44. This suppresses damage to the lead portions 23 and 24, preventing a decrease in the reliability of the inductor 1. Furthermore, it prevents the lead portions 23 and 24 from getting stuck on the electrode components 30 and 40, thus suppressing a decrease in production efficiency. Moreover, after riveting, the lead portions 23 and 24 are further fused to each connecting portion 34 and 44 in a manner that suppresses the foaming of the insulating coating, thereby suppressing the deterioration of the insulating coating and improving the DCR characteristics, enabling the manufacture of an inductor 1 with higher reliability.

[0106] [Variation Example] The following uses Figures 19A-19F The variations are explained. Figures 19A-19F This is a diagram illustrating the solder marks of the inductor in a modified example of the embodiment. Furthermore, in Figures 19A-19FIn the figures, (a) shows the shape of the first melt mark 34ma, and (b) shows the shape of the second melt mark 34mb. Additionally, in the figures, the path of the laser movement is represented by a double-dotted line, and the overlapping circles along this path indicate the expansion of the weld mark as the laser moves. It should be noted that there are no differences except for the shapes of the first melt mark 34ma and the second melt mark 34mb; therefore, other structures are omitted from the illustrations.

[0107] For example, in the above embodiment, a circular weld mark is shown, but the shape of the weld mark is not limited to a circle. For example, by moving the laser in a circular orbit, such as... Figure 19A As shown, it can also be formed into a roughly circular shape after circular movement. Furthermore, by moving the laser in a circular or arc-shaped track with an increased diameter, such as... Figure 19B As shown, it can also be formed into a ring shape after circular movement. Furthermore, by moving the laser within a circular or arc-shaped track with an increased diameter, such as... Figure 19C As shown, it can also be formed into an open ring after circular movement.

[0108] It should be noted that, in cases such as Figures 19A-19C When the laser moves in a circular or arc-shaped track, the initial and final irradiation positions can be set away from the insulating films of the leads 23 and 24, respectively; in other words, they can be set at the ends of the leads 23 and 24. This further suppresses the degradation of the insulating films of the leads 23 and 24 due to heat.

[0109] Additionally, by moving the laser along a straight track, such as... Figure 19D As shown, it can also become a straight line after circular movement. Furthermore, when moving the laser in a straight track, the laser output and movement speed can be adjusted while moving the laser, such as... Figure 19E As shown, it is also possible to form straight-line melt marks with circles of approximately the same size at each moment. Furthermore, by moving the laser within an amplitude orbit, as... Figure 19F As shown, it can also be formed into a circular, moving sawtooth shape.

[0110] It should be noted that, in cases such as Figures 19D-19F When the laser moves in a linear or amplitude-dependent orbit, the temperatures of the lead portions 23 and 24, the first riveting portion 34a, and the second riveting portion 34b at the point of final laser irradiation are higher than the temperatures at the point of initial laser irradiation. Therefore, the final laser irradiation point can be located away from the insulating film of the lead portions 23 and 24, in other words, at the end of the lead portions 23 and 24. By operating in this way, the thermal degradation of the insulating film of the lead portions 23 and 24 can be further suppressed.

[0111] The figures show examples where the circle gradually expands at different times as the laser moves, but as... Figure 19D as well as Figure 19E As illustrated, by moving the laser while adjusting its output and speed, a melt mark of any shape can be formed on any trajectory. However, as shown in the combination of figures (a) and (b), the laser is irradiated from the first riveting part 34a side toward the second riveting part 34b side, so the first melt mark 34ma is always larger in area than the second melt mark 34mb.

[0112] (Summarize) An example of an inductor and a method of manufacturing thereof is illustrated in this disclosure.

[0113] [Example 1] The inductor 1 in Example 1 includes: a magnetic core 10 having a bottom surface 18, a top surface 19 opposite to the bottom surface 18, and an end surface 13 connecting the bottom surface 18 and the top surface 19; a coil element 20 embedded in the magnetic core 10; and an electrode component 30 connected to the coil element 20. The coil element 20 has a winding portion 21 with a wire wrapped with an insulating film and a lead portion 23 extending from the end of the winding portion 21. The electrode component 30 has: a side plate portion 35 disposed along the end surface 13; a first lead portion 31 extending from the end 35a on the top surface 19 side of the side plate portion 35 into the interior of the magnetic core 10; and a connecting portion 34 connected to the first lead portion 31, which includes a second riveting portion 34b and a first riveting portion 34a in sequence close to the first lead portion 31, and the lead portion 23 is clamped and riveted inside the magnetic core 10 by the second riveting portion 34b and the first riveting portion 34a. The connecting portion 34 has: a first melt mark 34ma formed by melting and solidifying the first riveting portion 34a on the surface of the first riveting portion 34a; a second melt mark 34mb formed by melting and solidifying the second riveting portion 34b on the surface of the second riveting portion 34b; and a welding portion 34m formed by melting and solidifying the connecting portion 34 and the lead wire portion 23 between the first melt mark 34ma and the second melt mark 34mb.

[0114] By performing this operation, a joint with low DC resistance can be obtained after the first riveting part 34a, the lead part 23 and the second riveting part 34b are fused together by the first fusion mark 34ma and the second fusion mark 34mb. Therefore, an inductor 1 with improved DC resistance characteristics (DCR characteristics) and the ability to suppress reliability degradation can be achieved.

[0115] [Example 2] In Example 2, the inductor 1 is the same as the inductor 1 described in Example 1, where the area of ​​the first melt mark is larger than the area of ​​the second melt mark.

[0116] According to this structure, a tapered weld portion 34m that gradually tapers from the first riveting portion 34a toward the second riveting portion 34b can be formed. This can be formed by irradiating a laser from the first riveting portion 34a toward the second riveting portion 34b. In the initial stage of welding for forming the weld portion 34m, the portion irradiated by the laser (i.e., the portion where the first melt mark is formed) is close to the edge 34e of the connecting portion 34, and therefore begins to melt with less heat. As melting proceeds, the heat applied to the lead portion 23 is easily conducted from the irradiated back side (i.e., the second riveting portion 34b) to the side plate portion 35, which serves as the main body of the electrode component. As a result, a joint with low DC resistance can be obtained, and it is easy to suppress the deterioration of the insulation coating of the wire due to the heat during welding. Therefore, an inductor 1 in which the insulation function of the insulation coating is not easily damaged and the reliability reduction can be suppressed can be achieved.

[0117] [Example 3] The inductor 1 in Example 3 is the inductor 1 according to Example 1 or Example 2, wherein the sum of the area of ​​the first melt mark 34ma and the area of ​​the second melt mark 34mb is more than 20% of the cross-sectional area of ​​the conductor.

[0118] Based on this structure, the cross-sectional area of ​​the welded part 34m can be easily increased relative to the cross-sectional area of ​​the conductor, making it easy to achieve an inductor 1 with further improved DC resistance characteristics.

[0119] [Example 4] The inductor 1 in Example 4 is the inductor 1 in any one of Examples 1 to 3. The average area diameter of the crystalline structure of the welded part is greater than the average area diameter of the welded part 34m in the connecting part 34. The average area diameter of the crystalline structure of the welded part 34m is 5 μm or more and 100 μm or less.

[0120] According to this structure, the average area diameter of the crystalline structure of the weld portion 34m is larger than the average area diameter of the weld portion 34m outside the periphery of the connecting portion 34. By setting the average area diameter of the crystalline structure of the weld portion 34m to be more than 5μm and less than 100μm, it is possible to ensure that the weld portion 34m has a strength that is not easy to break. By setting the average area aspect ratio of the crystalline structure of the weld portion 34m to be less than 7, the crystallization strain can be reduced, and thus the strength of the weld portion 34m can be further improved.

[0121] [Example 5] The manufacturing method of the inductor 1 in Example 5 is a method for manufacturing an inductor 1 having a coil element 20 embedded in a magnetic core 10 and an electrode component 30 connected to the coil element 20, including a coil element forming process (S10), an electrode component pre-forming process (S20), a connecting process (S30), and a magnetic core forming process (S40). The coil element forming process (S10) forms a coil element 20 having a winding portion 21 and a lead portion 23 extending from the end of the winding portion 21. The electrode component pre-forming process (S20) forms an electrode component 30, which has a side plate portion 35 arranged along a predetermined direction, a first lead portion 31 bent at one end in a predetermined direction of the side plate portion 35, and a connecting portion 34 extending from the first lead portion 31 and sequentially including a second riveting portion 34b and a first riveting portion 34a in order close to the first lead portion 31. The connecting process (S30) connects the lead portion 23 to the connecting portion 34. In the core forming process (S40), the coil element 20, the first lead-out portion 31, and the connecting portion 34 are embedded in the magnetic core 10. In the connecting process, the connecting portion 34 between the first fusion mark 34ma and the second fusion mark 34mb, and the lead portion 23 are fused together by the following steps: The lead portion 23 is clamped and riveted by the second riveting portion 34b and the first riveting portion 34a. Then, a laser is irradiated onto the surface of the first riveting portion 34a in a direction from the surface of the first riveting portion 34a toward the surface of the second riveting portion 34b, forming a fusion mark (i.e., the first fusion mark 34ma) formed by melting and solidifying the first riveting portion 34a on the surface of the first riveting portion 34a, and a fusion mark (i.e., the second fusion mark 34mb) formed by melting and solidifying the second riveting portion 34b on the surface of the second riveting portion 34b. This operation fuses the connecting portion 34 between the first fusion mark 34ma and the second fusion mark 34mb, and the lead portion 23 together.

[0122] According to this manufacturing method, the inductor 1 described in Example 1 can be manufactured.

[0123] (Other implementation methods, etc.) The inductor and its manufacturing method according to the embodiments of the present disclosure have been described above, but the present disclosure is not limited to the above embodiments. Various modifications to the embodiments that can be conceived by those skilled in the art, as well as other ways of constructing by combining some of the constituent elements of the embodiments, are also included within the scope of the present disclosure, as long as they do not depart from the spirit of the present disclosure.

[0124] In the above embodiment, an example is shown where the connecting portion 34 connected to the first lead-out portion 31 and the lead portion 23 are joined, and the connecting portion 44 connected to the first lead-out portion 41 and the lead portion 24 are joined, but this is not a limitation. For example, if the connecting portion is provided at the second lead-out portion instead of the first lead-out portion, the connecting portion connected to the second lead-out portion 32 and the lead portion 23 may be joined, and the connecting portion connected to the second lead-out portion 42 and the lead portion 24 may be joined.

[0125] In the above embodiment, an example is shown where protrusions 33 and 43 are provided and the first riveting portion 34a is provided on the top surface 19 side of the magnetic core 10, but this is not a limitation. For example, protrusions 33 and 43 may not be provided, and the first riveting portion 34a may be provided on the bottom surface 18 side of the magnetic core 10. In this case, the connecting portion 34 and the lead portion 23 may be fused together by irradiating a laser from the side that forms the bottom surface 18 of the magnetic core 10.

[0126] In the above embodiments, an example of a circular cross-section for the wire is shown, but the embodiment is not limited to this. The cross-section of the wire may also be square. For easy connection to electrode components, the lead portion may also be at least partially extended into a flat plate shape.

[0127] Furthermore, electrical products or circuits using the aforementioned inductors are also included in this disclosure. Examples of electrical products include power supply devices equipped with the aforementioned inductors and various devices equipped with such power supply devices. Industrial applicability

[0128] The inductor disclosed herein is useful as an inductor for various devices and equipment, etc. Explanation of reference numerals in the attached figures

[0129] 1. Inductor 10 magnetic cores 10c Center 10cL line 10r corner 13 and 14 end faces Side views of 15 and 16 18 Bottom 18a Bottom concave part 19 Top surface 20 Coil Components 21. Winding section 21c winding shaft 23, 24 Lead sections 30 and 40 electrode components 31, 41 First Introduction 31g, 41g guide surface 32, 42 Second Lead-out Section 32h and 42h through holes 33, 43 protrusions 33e, 43e front-end 34, 44 connecting parts 34a First riveting part 34b Second riveting part 34e, 44e edge 34m Welding Section 34ma, 44ma First melt line 34mb, 44mb Second melt line 35, 45 Side Panel Section 35a, 45a end 35b and 45b ends 36, 46 First groove section 37, 47 Second groove section 38, 48 base plate 38a, 48a foot 61 pillars 62 Rotating components.

Claims

1. An inductor comprising: a magnetic core having a bottom surface, a top surface opposite to the bottom surface, and an end surface connecting the bottom surface and the top surface; a coil element embedded in the magnetic core; and an electrode component connected to the coil element, wherein, The coil element has a wound portion with a wire wrapped with an insulating film and a lead portion extending from the end of the wound portion. The electrode component includes: a side plate portion disposed along the end face; a first lead-out portion extending from the end of the side plate portion on the top surface side to the interior of the magnetic core; and a connecting portion connected to the first lead-out portion, comprising a second riveting portion and a first riveting portion in sequence adjacent to the first lead-out portion, and the lead portion being clamped and riveted inside the magnetic core by the second riveting portion and the first riveting portion. The connecting portion has: a first melt mark formed by melting and solidifying the first riveting portion on the surface of the first riveting portion; a second melt mark formed by melting and solidifying the second riveting portion on the surface of the second riveting portion; and a welded portion formed by melting and solidifying the connecting portion and the lead portion between the first melt mark and the second melt mark.

2. The inductor according to claim 1, wherein, The area of ​​the first melt mark is larger than the area of ​​the second melt mark.

3. The inductor according to claim 1 or 2, wherein, The sum of the area of ​​the first melt mark and the area of ​​the second melt mark is more than 20% of the cross-sectional area of ​​the conductor.

4. The inductor according to claim 1 or 2, wherein, The area average diameter of the crystalline structure in the welded portion is larger than the area average diameter of the portion outside the welded portion in the connecting portion. The area-average diameter of the crystalline structure in the welded part is 5 μm or more and 100 μm or less. The average aspect ratio of the crystalline structure in the welded part is less than 7.

5. A method for manufacturing an inductor, comprising a coil element embedded in a magnetic core and an electrode component connected to the coil element, the method comprising: A coil element forming process, which forms a coil element having a winding portion and a lead portion extending from the end of the winding portion; An electrode component pre-forming process for forming an electrode component, the electrode component having: a side plate portion arranged along a predetermined direction; a first lead-out portion bent at one end of the side plate portion in the predetermined direction; and a connecting portion extending from the first lead-out portion and sequentially including a second riveting portion and the first riveting portion in order close to the first lead-out portion; The connection process of connecting the lead portion and the connecting portion; and The magnetic core forming process involves embedding the coil element, the first lead-out portion, and the connecting portion within the magnetic core. In the connection process, the lead wire portion is clamped and riveted by the second riveting portion and the first riveting portion. A laser is irradiated on the surface of the first riveting portion along the direction from the surface side of the first riveting portion toward the surface of the second riveting portion, forming a melt mark, i.e., a first melt mark, formed by melting and solidifying the first riveting portion on the surface of the first riveting portion. A second melt mark, i.e., a second melt mark, is formed on the surface of the second riveting portion. The connection portion and the lead wire portion between the first melt mark and the second melt mark are then fused together.

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