Inductor

Abstract

An inductor (100) comprises: a three-dimensionally shaped magnetic core (10) comprising a magnetic material and having a side surface (12); a coil element (20) including an embedded portion (21) comprising a metal material and embedded in the magnetic core (10), and an end portion (22) exposed from the magnetic core (10) and extending along the side surface (12); and an electrode member (30) comprising a metal material and having flexibility, the electrode member (30) being disposed on a side opposite the magnetic core (10) with the end portion (22) therebetween. The electrode member (30) comprises a side surface portion (36) disposed along the side surface (12), the side surface portion (36) when viewed from the thickness direction thereof at least partially overlapping the end portion (22). The electrode member (30) and the magnetic core (10) are adhered to each other with an adhesive layer (30c) therebetween, the adhesive layer (30c) comprising a resin with an adhesive property. The electrode member (30) and the end portion (22) are welded to each other in at least a part of a region in which the side surface portion (36) and the end portion (22) overlap each other.

Description

Technical Field

[0001] This disclosure relates to an inductor.

Background Art

[0002] An inductor, which is a passive element that stores electrical energy as magnetic energy, is used in, for example, a DC-DC converter device for the purpose of boosting or bucking a power supply voltage or smoothing a direct current. For example, a surface mount type inductor that can be joined by a reflow method on a circuit board has also been developed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional inductor, the connection reliability with an external circuit may be lacking. In view of the above, an object of this disclosure is to provide an inductor with higher connection reliability.

Means for Solving the Problems

[0005] An inductor according to one aspect of the present disclosure comprises a magnetic core having a three-dimensional shape with sides, which includes a magnetic material; a coil element having a metal material, an embedded portion embedded in the magnetic core, and an end exposed from the magnetic core and extending along the sides; and a flexible electrode member having a metal material, which is disposed on the opposite side from the magnetic core, with the end of the coil element in between, wherein the electrode member has a side portion disposed along the sides of the magnetic core, and when viewed in the thickness direction of the side portion, at least a portion of the side portion overlaps with the end of the coil element; the electrode member and the magnetic core are bonded together via an adhesive layer containing an adhesive resin; and the electrode member and the end are welded together in at least a portion of the region where the side portion and the end overlap when viewed in the thickness direction of the side portion. [Effects of the Invention]

[0006] According to this disclosure, it is possible to provide an inductor with higher connection reliability. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a cross-sectional view of an inductor relating to a comparative example. [Figure 2] Figure 2 is a perspective view of an inductor according to an embodiment. [Figure 3] Figure 3 is a plan view of the inductor according to the embodiment, as seen from the top. [Figure 4] Figure 4 is a plan view of the inductor according to the embodiment, as seen from the bottom side. [Figure 5] Figure 5 is a plan view of the inductor according to the embodiment, as seen from the side. [Figure 6] Figure 6 is a plan view of an inductor according to another embodiment, as seen from the top. [Figure 7] Figure 7 shows an example of an inductor implementation according to the embodiment. [Figure 8] Figure 8 is a cross-sectional view of an inductor according to an embodiment. [Figure 9]Figure 9 is a flowchart showing a method for manufacturing an inductor according to an embodiment. [Modes for carrying out the invention]

[0008] (Background leading to this disclosure) As mentioned earlier, inductors are used in many electronic devices in recent years. In particular, inductors are sometimes mounted on circuit boards, and surface-mount inductors designed for mounting on pads on circuit boards have also been developed.

[0009] For example, Figure 1 is a cross-sectional view of a surface-mount type inductor 100x according to a comparative example. The inductor 100x shown in Figure 1 is similar to the inductor in Patent Document 1 and comprises a coil element 20x, a magnetic core 10x surrounding the coil element 20x, and an electrode member 30x connected to the coil element 20x. The coil element 20x has an embedded portion 21x embedded in the magnetic core 10x and an end portion 22x that protrudes to the outside from the side surface of the magnetic core 10x. The end portion 22x of the coil element 20x is bent along the side surface of the magnetic core 10x and extends toward the bottom surface (the surface along the bottom edge of the paper).

[0010] The electrode member 30x is positioned on the side surface of the magnetic core 10x so as to overlap the outer end 22x of the coil element 20x, and is further bent to conform to the bottom surface of the magnetic core 10x. The electrode member 30x and the end 22x are joined by a bonding material (not shown). Here, the end 22x and the electrode member 30x are joined by the bonding material before being bent to conform to the bottom surface of the magnetic core 10x, and then bent to conform to the bottom surface of the magnetic core 10x after being joined.

[0011] Therefore, after bending the end portion 22x and the electrode member 30x, the state of the joint cannot be visually confirmed by the outer electrode member 30x. Consequently, it may become impossible to detect abnormalities in the joint state, such as insufficient bonding material or, as a result, cracks occurring in the joint or the joint coming apart during the bending process.

[0012] When using inductor 100x, if there is an abnormality in the junction between the coil element 20x and the electrode member 30x as described above, it is expected that the power supply to the coil element 20x will not be sufficient, resulting in the expected performance not being achieved, and that the electrical resistance at the junction will increase, causing malfunctions such as abnormal heat generation.

[0013] Furthermore, as shown in the figure, a gap may be formed between the end 22x of the coil element 20x and the magnetic core 10x of the inductor 100x. Also, a gap may be formed between the electrode member 30x, which is joined to the end 22x of the coil element 20x via a bonding material, and the magnetic core 10x. Thus, even if the end 22x and the electrode member 30x are bent along the magnetic core 10, strictly speaking, a gap is formed between them and the magnetic core 10x, and the magnetic core 10x appears to be "floating" when viewed from the circuit board on which the inductor 100x is mounted.

[0014] The inductor 100 may be subjected to driving vibrations depending on the operating environment, such as when it is mounted in a vehicle. As a result, the magnetic core 10x, which is floating above the circuit board, may swing like a pendulum due to the vibrations. In this case, vibration stress may concentrate at the end portion 22x that supports the magnetic core 10x, and at the connection points between the bottom plate 34x bent on the underside of the magnetic core 10x and the side plate 36x along the end portion 22x (i.e., the bent portion of the electrode member 30x), which may cause damage (breakage) at these points.

[0015] Therefore, in the present disclosure, in view of the above, an inductor having higher connection reliability will be described. Specifically, the inductor according to the present disclosure includes a three-dimensional core having a magnetic material and having side surfaces, a buried portion including a metal material and buried in the core, and a coil element having an end portion exposed from the core and extending along the side surface, and an electrode member including a metal material and having flexibility, the electrode member being disposed on the opposite side of the core across the end portion of the coil element. The electrode member is a side surface portion disposed along the side surface of the core, and has a side surface portion at least partially overlapping the end portion of the coil element when viewed from the thickness direction of the side surface portion. The electrode member and the core are adhered via an adhesive layer including an adhesive resin. The electrode member and the end portion are welded at least partially in a region where the side surface portion and the end portion overlap when viewed from the thickness direction of the side surface portion.

[0016] Since the electrode member has flexibility, the electrode member can be bent following the shape of the core and the end portion of the inductor. Therefore, the electrode member and the end portion of the coil element can be stably welded. Since this welding is performed after the electrode members are overlapped, for example, the suitability of the welding can also be confirmed after manufacturing by checking the welding marks or the like.

[0017] Further, for example, by overlapping and adhering the electrode member after bending the end portion, compared with the case where the end portion and the electrode member are bent simultaneously, no load is applied to the bonding material due to a change in the positional relationship between them due to the difference in bending characteristics during bending.

[0018] In addition, since the electrode member is adhesively held to the magnetic core, which is the main part from the perspective of weight, the inductor after mounting behaves like an integrated body in which the magnetic core and the electrode member are integrated. In particular, the electrode member employed in the present disclosure has flexibility and thus follows the shape of the magnetic core and has a shape close to the outer surface of the magnetic core as described above. As a result, the adhesive layer for adhering the electrode member and the magnetic core can be made thinner, and the integration of the magnetic core and the electrode member becomes more advanced. For example, even when the inductor is mounted in a vehicle and is affected by running vibrations, the magnetic core and the electrode member of the inductor move integrally with respect to the circuit board on which the electrode member is mounted, so that damage to each part due to concentration of vibration stress can be suppressed. In this way, higher connection reliability is ensured in the inductor according to the present disclosure.

[0019] Hereinafter, embodiments will be described more specifically with reference to the drawings.

[0020] Note that each of the embodiments described below shows a specific example of the present disclosure. The numerical values, shapes, materials, components, arrangement positions of the components, connection forms, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. In addition, among the components in the following embodiments, components not described in the independent claims are described as optional components.

[0021] In each figure, an X-axis, a Y-axis, and a Z-axis, which mean three mutually orthogonal directions, are shown, and these axes and the axial directions along the axes are used for explanation as necessary. In the following description, the Z-axis direction may be expressed as the first direction and the X-axis direction may be expressed as the second direction. Note that each axis is provided for explanation purposes and does not limit the direction and posture in which the inductor is used.

[0022] (Embodiment) [Configuration] The inductor in the embodiment will be described with reference to Figures 2 to 8. Figure 2 is a perspective view of the inductor according to the embodiment. In Figure 2, the configuration visible from the outside of the inductor 100 according to the embodiment is shown by solid lines. Also in Figure 2, the configuration visible when light is transmitted through the magnetic core 10 of the inductor 100 is shown by dashed lines.

[0023] Figure 3 is a plan view of the inductor according to the embodiment, viewed from the top. Figure 4 is a plan view of the inductor according to the embodiment, viewed from the bottom. Figure 5 is a plan view of the inductor according to the embodiment, viewed from the side.

[0024] In Figures 3, 4, and 5, the adhesive 50, as seen when light passes through the electrode member 30, is shown with dot hatching. Also in Figures 3, 4, and 5, the configuration of each part, as seen when light passes through the electrode member 30, is shown with dashed lines.

[0025] As shown in Figure 2, the inductor 100 according to this embodiment comprises a magnetic core 10, a coil element 20, and an electrode member 30.

[0026] The inductor 100, for example, has a rectangular parallelepiped-shaped powdered magnetic core, and its approximate external shape is determined by the shape of the magnetic core 10. The magnetic core 10 can be formed into any shape by molding. In other words, an inductor 100 of any shape can be realized depending on the shape of the magnetic core 10 during molding. The inductor 100 of this embodiment is composed of a magnetic core 10 with dimensions of 4 mm to 12 mm in the X-axis direction, 4 mm to 12 mm in the Y-axis direction, and 2 mm to 8 mm in the Z-axis direction.

[0027] The magnetic core 10 is the outer shell portion of the inductor 100 and covers a part of the coil element 20. The magnetic core 10 is, for example, a compacted magnetic core made of metallic magnetic powder and resin material. The magnetic core 10 can be formed using any magnetic material, such as ferrite, or other materials. For the metallic magnetic powder, particulate materials having a predetermined elemental composition such as Fe-Si-Al, Fe-Si, Fe-Si-Cr, or Fe-Si-Cr-B are used. For the resin material, a material such as silicone is selected that can maintain a certain shape by insulating the particles of the metallic magnetic powder while binding them together.

[0028] The magnetic core 10 has a shape, for example, that of a rectangular parallelepiped, and has a bottom surface 13, four sides connected to the bottom surface 13, and a top surface 14 connected to the four sides and facing away from the bottom surface 13. The four sides are composed of two sides 11 facing away from each other in the X-axis direction and two sides 12 facing away from each other in the Y-axis direction. Each of the four sides 11 and 12 has a flat surface perpendicular to the bottom surface 13. As shown in Figure 3, a recess 12b is formed in the side 12, which is concave toward the inside of the magnetic core 10. The end portion 22 of the coil element 20, which will be described later, is housed in this recess 12b. The part of the side excluding the recess 12b is called the base portion 12a.

[0029] The coil element 20 has an embedded portion 21 and a plurality of end portions 22 connected to the embedded portion. The coil element 20 in this embodiment is composed of one embedded portion 21 and two end portions 22. The coil element 20 is made of a material selected from metallic materials such as aluminum, copper, silver, and gold, as well as alloys made of metal and other substances. The embedded portion 21 and the end portions 22 are designations given to the respective parts formed by processing a single member made of the same material.

[0030] The end portion 22 is not covered by the magnetic core 10 and is exposed from the side surface 12 of the magnetic core 10. The end portion 22 is extended in a flat shape and extends along the side surface 12 toward the top surface 14 (i.e., along the Z-axis direction), and is interrupted before reaching the top surface 14. In other words, the end portion 22 is the portion of the coil element 20 that is positioned on the side surface 12. Because the end portion 22 of the coil element 20 is configured without protruding from the side surface 12 of the magnetic core 10, for example toward the positive Z-axis direction, the inductor 100 can be configured compactly, and unintended contact with external conductive members is suppressed.

[0031] The buried portion 21 is the part covered by the magnetic core 10. The buried portion 21 is made by winding a long piece of material and functions as a coil. There are no particular limitations on the number of turns of the buried portion 21; for example, 0.5 turns, 10 turns, or 100 turns can be appropriately selected according to the performance required of the inductor 100 and constraints such as the size of the magnetic core 10. The buried portion 21 is formed, for example, by bending a copper wire covered with an insulating coating. The cross-section of the copper wire constituting the buried portion 21 is circular, with a diameter of 0.16 to 1.40 mm, and the aspect ratio of the copper wire's cross-section (transverse surface) is 1:1.

[0032] The buried portion 21 is positioned such that the wound winding shaft is aligned with the Z-axis direction. The buried portion 21 has a curved portion formed by winding and a straight portion connecting the curved portion and the end portion 22. The straight portion of the buried portion 21 extends in the Y-axis direction toward the side surface 12 of the magnetic core 10 where the end portion 22 is located and is connected to the end portion 22.

[0033] The electrode member 30 has a side portion 36, a bottom portion 34, and a top portion 33. The electrode member 30 is made of a material selected from metallic materials such as aluminum, copper, silver, and gold, as well as alloys made of metal and other substances. For example, in the inductor 100 of this embodiment, an electrode member 30 containing copper or a copper alloy is selected.

[0034] The electrode member 30 is configured to be flexible, and is realized, for example, by a foil material having a thickness of 20 μm or more and less than 100 μm. The flexibility of the electrode member 30 allows it to be bent to follow the surface of the end portion 22 and the magnetic core 10.

[0035] As a result, the electrode member 30 is integrated with the surface of the magnetic core 10. For example, when vibration is applied to the inductor 100, the magnetic core 10 of the inductor 100 and the electrode member 30 can move together with respect to the circuit board 99 (see Figure 7, described later) on which the electrode member 30 is mounted. Therefore, it is possible to suppress the occurrence of cracks in the parts between the electrode member 30, which is fixed to the circuit board 99 during mounting, and the main parts (magnetic core 10 and embedded part 21) and end parts 22 of the inductor 100 in terms of weight. In this way, the inductor 100 can have high connection reliability. In this context, the flexibility of the electrode member 30 means that when the side portion 36 of the electrode member 30 is pressed against the side portion 12 and end portion 22 of the magnetic core 10, it is possible to plastically deform in accordance with the surface of the side portion 12 and end portion 22 of the magnetic core 10 without deforming the end portion 22. Furthermore, when the electrode member 30 is bonded to the magnetic core 10 via the adhesive 50 described later, the shape of the electrode member 30 can be maintained based on the holding force of the adhesive 50 after hardening. In other words, the flexible electrode member 30 means that when the side portion 36, top portion 33, and bottom portion 34 described later are formed by bending, the reaction force of bending does not overcome the holding force of the adhesive 50, and the parallel relationship between the main surface of the side portion 36 and the side portion 12, the parallel relationship between the main surface of the top portion 33 and the top portion 14, and the parallel relationship between the main surface of the bottom portion 34 and the bottom portion 13 are not substantially disrupted.

[0036] Electrode members 30 are provided one on each side of the inductor 100 in the Y-axis direction, corresponding to each of the two ends 22. Here, one of the two electrode members 30 will be described, but the same description applies to the other electrode member 30 as they have the same configuration. The side portion 36, bottom portion 34, and top portion 33 are names given to the respective parts formed by processing a single member made of the same material.

[0037] The side portion 36 is a part provided along the side portion 12 of the magnetic core 10, corresponding to the side portion 12 of the magnetic core 10. The side portion 36 is positioned so as to overlap the end portion 22 of the coil element 20 and is fixed to the end portion 22 by a joining described later. The side portion 36 is configured such that the portion that overlaps with the end portion 22 absorbs the thickness of the end portion 22, so that the portion that does not overlap with the end portion 22 faces the side portion 12 of the magnetic core 10.

[0038] More specifically, the side portion 36 has a first region where the side portion 36 and the side portion 12 face each other, and the end portion 22 of the coil element 20 is not interposed between the side portion 36 and the side portion 12 of the magnetic core 10. The first region corresponds, for example, to the base portion 12a. The side portion 36 also has a second region, different from the first region, where the side portion 36 and the side portion 12 face each other via the end portion 22 of the coil element 20. The second region corresponds to the recess 12b. Therefore, the second region of the side portion 36 faces the end portion 22 of the coil element 20 housed in the recess 12b. The second region is positioned offset from the first region in the direction away from the side portion 12, and the first and second regions together form an electrode recess that is concave in the direction away from the side portion 12.

[0039] The end portion 22 of the coil element 20 is housed in the recess 12b in the Y-axis direction (extended thickness), and when viewed from the Z-axis direction (direction perpendicular to the thickness direction of the side portion 36), the remaining portion protrudes from the base portion 12a by a distance of 5.00 μm or more and 100 μm or less from the magnetic core 10. Since the electrode member 30 is positioned to cover this protruding portion, the electrode recess is naturally formed by bringing the first region of the electrode member 30 into contact with the base portion 12a, in combination with the flexible nature of the electrode member 30.

[0040] As shown in Figure 3, the electrode recess in this embodiment is formed by a second region sandwiched in the X-axis direction between two first regions, and together with the recess 12b, it accommodates the end portion 22 of the coil element 20. Specifically, the electrode member 30 is positioned so that the end portion 22 contacts the surface of the second region on the magnetic core 10 side (hereinafter also referred to as the bottom of the electrode recess). The depth of the electrode recess (the size of the internal space in the Y-axis direction) corresponds to the thickness of the end portion 22 that protrudes outward from the base portion 12a, as shown by the white arrow in the figure, for example, and is between 5.00 μm and 100 μm. In this way, the minimum necessary electrode recess is formed to match the outwardly protruding end portion 22, making it possible to realize a compact inductor 100.

[0041] In Figure 3, the end portion 22 of the coil element 20 is shown as a flat plate, and when viewed from the Z-axis direction (a direction perpendicular to the thickness direction of the side portion 36), the part that protrudes away from the magnetic core 10 from the base portion 12a has a flat shape (i.e., a flat surface) with multiple points at the furthest distance from the magnetic core 10. However, the invention is not limited to this. For example, instead of the flat surface described above, the end portion may have a curved shape (i.e., a curved surface) when viewed from the Z-axis direction. An example will be explained with reference to Figure 6. Figure 6 is a plan view of an inductor according to another embodiment, viewed from the top side. In Figure 6, an inductor 100A according to another example is shown from the same viewpoint as in Figure 3 (a plan view from the Z-axis direction perpendicular to the thickness direction of the side portion 36), and an enlarged plan view of the area A3 around its end portion 22A is shown. Note that in the plan view in the figure, a part of the positive Y-axis side is omitted from the illustration. Furthermore, in the plan view and the enlarged plan view shown in the figure, corresponding corners of region A3 are connected by dashed lines.

[0042] The end portion 22A of the coil element 20 may have a continuously (smooth) curved surface, as shown in the enlarged plan view from the top surface 14 side of the inductor 100A according to another example of this embodiment, as shown in Figure 6. When viewed from the Z-axis direction (direction perpendicular to the thickness direction of the side portion 36), the other portion of the end portion 22A is convex in the direction away from the magnetic core 10. In this case, when viewed from the Z-axis direction, the only place on the other portion that is furthest from the magnetic core 10 is the tip of the convexity. As shown in the figure, in the above plan view, the surface of the end portion 22A on the negative side in the Y-axis direction has a convex curved shape in which the distance from the magnetic core 10 increases as it approaches the center in the width direction from both ends in the width direction (X-axis direction). The end portion 22A in this example has a curved surface in which the above curved shape is continuous in the Z-axis direction and is in contact with the side portion 36 by the curved surface.

[0043] This makes it less likely for a gap to form between the side portion 36 and the end portion 22A when the side portion 36 is pressed against the end portion 22A in order to position the side portion 36 on the side surface 12. Therefore, it is possible to make surface contact between the electrode member 30 and the entire curved surface of the rest of the end portion 22A.

[0044] Furthermore, the radius of curvature in the curved shape of the other part decreases as it moves away from the tip of the convex point furthest from the magnetic core 10 along the curved shape. Specifically, in the plan view described above, the radius of curvature R1 at both ends of the other part in the width direction is smaller than the radius of curvature R2 at the central part of the other part in the width direction, i.e., at the tip of the convex point furthest from the magnetic core 10 in the thickness direction of the end 22A. The radius of curvature gradually changes from R1 to R2 along the curved shape. In other words, the other part in this example has a curved surface in which the curvature gradually increases from the central part to both ends in the width direction.

[0045] As a result, when the side portion 36 is pressed against the end portion 22A, the stress that causes plastic deformation of the side portion 36 is greater at the two locations corresponding to the ends of the other part in the width direction, which have smaller radii of curvature, than at the location corresponding to the tip of the protrusion of the other part, which has a larger radius of curvature. Therefore, the side portion 36 is pulled between the two portions corresponding to the ends of the other part in the width direction, and is drawn towards the curved surface of the end portion 22A, centered on the portion corresponding to the tip of the protrusion of the other part, resulting in a tighter contact. Furthermore, when the side portion 36 is in surface contact with the curved surface of the other part, it undergoes plastic deformation with both sides of the portion corresponding to the tip of the protrusion of the other part, which has a larger radius of curvature, sandwiched between the ends of the other part, which have smaller radii of curvature. This creates a residual stress between the other part and the side portion 36 that maintains the state of tight contact, allowing the surface contact to be stably maintained.

[0046] As a result, the side portion 36 can be easily brought into surface contact with the end portion 22A, thereby improving the accuracy of the joint when joining the side portion 36 and the end portion 22A as described later (a stable joint can be achieved). Therefore, the reliability of the electrical connection at the joint of the inductor 100A is ensured. In this example, an inductor 100A with high connection reliability can be realized.

[0047] As shown in Figure 5, adhesive 50 is placed on the main surface of the electrode member 30 on the magnetic core 10 side, which corresponds to the first region. As the adhesive 50, for example, a resin-adhesive resin such as a thermosetting epoxy resin or silicone resin is used.

[0048] The adhesive 50 is interposed between the electrode member 30 and the magnetic core 10, bonding them together. As shown in the figure, the adhesive 50 is arranged in an area that broadly covers the opposing surfaces of the electrode member 30 and the magnetic core 10. For example, in the side portion 36, the adhesive 50 is arranged in a range of 50% to 80% of the total area of ​​the side portion 12. In the figure, the adhesive 50 is not provided in the area corresponding to the second central area in the X-axis direction. This area where the adhesive is not provided will be explained in detail later.

[0049] In this embodiment, due to the flexibility of the electrode member 30, the gap between the electrode member 30 and the magnetic core 10 is very small. Therefore, the adhesive layer 30c (see Figure 8), which will be described later, can be made thinner, resulting in a higher level of integration between the electrode member 30 and the magnetic core 10.

[0050] In this embodiment, the adhesive 50 is placed in the area corresponding to the first region of the side portion 36 facing the side surface 12, and also between the main surfaces of the top surface 33 and bottom surface 34 on the magnetic core 10 side and a part of the top surface 14 and bottom surface 13 of the magnetic core 10 (the part corresponding to the first region of the side portion 36), as shown in Figures 3 and 4. By bonding the electrode member 30 and the magnetic core 10 over such a wide area, the possibility of the electrode member 30 falling off the magnetic core 10 is reduced. Therefore, the reliability of the connection between the coil element 20, which is partially embedded and fixed in the magnetic core 10, and the electrode member 30 is improved.

[0051] A fusion portion 32 related to the joining with the end portion 22 of the coil element 20 is formed on the side portion 36. More specifically, the fusion portion 32 is formed by the integration of the end portion 22 and the side portion 36. In other words, the fusion portion 32 can be considered as part of the side portion 36 or as part of the end portion 22.

[0052] The penetration portion 32 is formed, for example, by welding from the outside of the side portion 36 in the region where the end portion 22 and the side portion 36 overlap, such as by lap joint laser welding. The welding of the end portion 22 and the side portion 36 will be explained in detail later. As described above, the penetration portion 32 is formed in the overlapping portion 22a of the end portion 22, which is the part that overlaps with the side portion 36. For example, as shown in Figure 5, when viewed from the thickness direction (Y-axis direction) of the side portion, the end portion 22 and the side portion 36 overlap in the overlapping portion 22a, and the penetration portion 32 is formed in the region corresponding to the overlapping portion 22a. On the other hand, the end portion 22 has a non-overlapping portion 22b that does not overlap with the side portion 36.

[0053] Since the non-overlapping portion 22b is exposed from the side portion 36 when viewed from the thickness direction of the side portion 36, it can be used to estimate the location of the overlapping portion 22a. For example, it can be estimated that the overlapping portion 22a is located in the range where a straight line connects the connection point of the embedded portion 21 and the end portion 22, which are designed to be at a predetermined distance from the end of the side portion 12 of the magnetic core 10, to the non-overlapping portion 22b. Therefore, the position where the end portion 22 overlaps with the side portion 36 can be accurately determined and welding can be performed, thereby improving the reliability of the welding. Consequently, an inductor 100 with high connection reliability can be manufactured.

[0054] Furthermore, after welding, by estimating the location of the overlapping portion 22a in the same manner as described above, it is possible to identify false penetration portions formed in areas of the multiple penetration portions 32 that do not correspond to the overlapping portion 22a. In this case, measures can be taken such as forming a new penetration portion 32 to replace the identified false penetration portion, or discarding the inductor 100. By providing a non-overlapping portion 22b in this way, it is possible to provide an inductor 100 with higher connection reliability.

[0055] The coil element 20 is formed using copper wire covered with an insulating coating, but the insulating coating is removed in the area where the penetration portion 32 is formed. Welding is performed to form the penetration portion 32 in the uncovered area that is not covered by the insulating coating. In general welding, two base materials involved in the welding are heated to a high temperature and melted, and the base materials mix with each other and harden, fixing them together. At this time, if organic substances such as an insulating coating are present, they will gasify at the high temperature during melting, hindering the mixing of the base materials and causing welding errors. Therefore, by forming the penetration portion 32 in the uncovered area where the insulating coating has been removed as described above, the occurrence of welding errors can be suppressed, and an inductor 100 with high connection reliability can be realized.

[0056] Here, multiple penetration portions 32 can be formed as described above. For example, in the inductor 100 in this embodiment, four penetration portions 32 are formed on each electrode member 30, resulting in a total of eight penetration portions 32 across the two electrode members 30. By forming multiple penetration portions 32, the inductor 100 will function normally if the electrode member 30 and the end portion 22 are properly joined in some of the multiple penetration portions 32. In other words, an inductor 100 that can be used normally can be realized even if welding errors occur in some of the penetration portions 32.

[0057] The bottom portion 34 is a part provided in correspondence with the bottom surface 13 of the magnetic core 10. The bottom portion 34 is integrated with the side portion 36 at a position corresponding to the boundary between the side portion 12 and the bottom surface 13 of the magnetic core 10, and extends along the bottom surface 13 toward the center of the magnetic core 10. The top portion 33 is a part provided in correspondence with the top surface 14 of the magnetic core 10. The top portion 33 is integrated with the side portion 36 at a position corresponding to the boundary between the side portion 12 and the top surface 14 of the magnetic core 10, and extends along the top surface 14 toward the center of the magnetic core 10. The top portion 33 corresponds to the first region of the side portion 36, and extends along the top surface from each of the two first regions that sandwich the second region of the side portion 36. Thus, the top portion 33 consists of two parts separated by the removal of the central part in the X-axis direction. Furthermore, compared to the case where the top surface portion 33 is not provided and a protruding portion from the electrode member 30 is inserted into and fixed to a part of the magnetic core 10, this configuration does not obstruct the magnetic flux inside the magnetic core 10, thus enabling the realization of a magnetically advantageous inductor 100.

[0058] Figure 7 shows an example of inductor mounting according to an embodiment. Figure 7 shows the inductor 100 mounted on the circuit board 99 as viewed from the X-axis direction. For example, as shown in Figure 7, when the inductor 100 is mounted on the circuit board 99, the bottom portion 34 is connected to a land 98 on the circuit board 99 via a bonding material 97 such as solder.

[0059] At this time, a fillet is formed on the side portion 36 by the bonding material 97 used to connect to the land 98. As described above, in this embodiment, the inductor 100 does not use bonding material for the electrical connection between the electrode member 30 and the end portion 22. For example, when mounting it on the circuit board 99, other bonding material will not be mixed into the bonding material 97 used to connect to the land 98 from the inductor 100 side. In other words, the inductor 100 can be mounted without the properties of the bonding material 97 changing. Since the bonding material 97 is appropriately selected according to the application of the inductor 100, an inductor 100 that can perform as specified can be realized without changing its properties. When mounting the inductor 100 on the circuit board 99, it is necessary to move the top surface 14 to the position of a predetermined land 98 on the circuit board 99 by using a nozzle to suck it up.

[0060] When the top surface portion 33 is provided on the side of the top surface 14, a step is formed between the main surface of the top surface portion 33 on the positive Z-axis side and the top surface 14. On the other hand, since it is necessary to secure a flat surface for the nozzle suction described above, for example, the area of ​​the main surface of the top surface portion 33 along the top surface 14 may be designed to be smaller than the area of ​​the main surface of the bottom surface portion 34 along the bottom surface 13. This makes it possible to secure a wide flat surface for nozzle suction when mounting the inductor 100, and various suction nozzles can be used to mount the inductor 100.

[0061] For the reasons described above, for example, as shown by the white double arrows in Figure 7, the length of the top surface 33 is shorter than the length of the bottom surface 34 in the Y-axis direction. Also, as shown in Figures 3 and 4, although the length between the two ends of the top surface 33 is equal to the length of the bottom surface 34 in the X-axis direction, the top surface 33 has a shape in which the central part in the X-axis direction has been removed. For example, if the part of the suction nozzle corresponding to the top surface 14 is circular, removing the central part in the X-axis direction increases the area of ​​the effective flat surface. In this way, by designing the main surface area of ​​the top surface 33 along the top surface 14 to be smaller than the main surface area of ​​the bottom surface 34 along the bottom surface 13, a wider variety of suction nozzles can be used to mount the inductor 100.

[0062] Furthermore, the top surface portion 33 prevents the magnetic core 10 from falling off the electrode member 30 in the positive Z-axis direction. More specifically, for example, if the adhesion by the adhesive 50 on the side portion 36 is insufficient, the magnetic core 10 may move in the Z-axis direction relative to the electrode member 30. In this case, the presence of the top surface portion 33 allows the magnetic core 10 to be held down from the positive Z-axis direction, thus preventing the magnetic core 10 from falling off the electrode member 30 in the positive Z-axis direction, even when subjected to vibrations, for example. In addition, in the inductor 100 of this embodiment, two separate top surface portions 33 are formed for each electrode member 30, and the two electrode members 30 are configured to hold down the rectangular parallelepiped-shaped inductor 100 from the four corners of the top surface 14, resulting in a higher effect in preventing the magnetic core 10 from falling off.

[0063] Figure 8 is a cross-sectional view of an inductor according to an embodiment. Figure 8(a) shows a cross-sectional view when the inductor 100 is cut along the AA section shown in Figure 8(b). Figure 8(b) also shows a cross-sectional view when the inductor 100 is cut along the BB section shown in Figure 8(a). In addition, enlarged cross-sectional views of region A1 and region A2 of the cross-sectional view shown in Figure 8(a) are also shown.

[0064] As shown in Figures 8(a) and 8(b), the side portion 36 is attached to the side surface 12 of the magnetic core 10. The electrode member 30, including the side portion 36, is physically and electrically connected to the end 22 of the coil element 20 via the penetration portion 32.

[0065] As shown in the enlarged cross-sectional view of region A1, the electrode member 30 has an electrode layer 30a, a plating layer 30b formed on the surface of the electrode member 30 so as to cover the electrode layer 30a, and an adhesive layer 30c. The electrode layer 30a is the main part of the electrode member 30 and is made of copper or copper alloy foil. The plating layer 30b is made of tin or solder, and the boundary portion between the electrode layer 30a and the outside is plated.

[0066] As a result, a plating layer 30b is formed on the surface of the electrode member 30. The plating layer 30b is provided to improve the wettability so that the bonding material 97 can spread evenly across the surface of the side portion 36 when the inductor 100 is mounted on the circuit board 99. In addition, the plating layer 30b is formed of a material with relatively high thermal resistance, so heat is easily generated by laser irradiation during welding. Therefore, it is easier to secure the heat necessary for welding, thereby improving the ease of welding.

[0067] The adhesive layer 30c is a layer formed by the adhesive 50. The adhesive 50 is applied to the surface of the plating layer 30b on the electrode member 30 (here, the surface on the positive side in the Y-axis direction), and hardens after being attached to the magnetic core 10. After hardening, the adhesive layer 30c, which is the hardened resin layer of the adhesive 50, is formed. The adhesive 50 may also be applied to the magnetic core 10. In this case, the electrode member 30, consisting of the electrode layer 30a and the plating layer 30b, is attached before the adhesive 50 hardens, and after hardening, a configuration similar to the enlarged cross-sectional view of region A1 is achieved. Therefore, the adhesive layer 30c can also be considered as part of the structure of the magnetic core 10.

[0068] In the enlarged cross-sectional view of region A2, the adhesive layer 30c is not present on the surface of the electrode member 30. As explained with reference to Figure 5, the adhesive 50 is provided in the area corresponding to the first region. On the other hand, the adhesive 50 is not provided in the area corresponding to the second region. Since the adhesive 50 mainly contains organic materials, similar to the insulating film described above, if it is present near the base material during welding, it will gasify and hinder welding. For this reason, the adhesive 50 is not placed in the second region, which is the area involved in welding, and the adhesive layer 30c is not formed there.

[0069] Furthermore, as shown in the enlarged cross-sectional view of region A2, the penetration portion 32 extends from the outer surface of the side portion 36 to the interior of the end portion 22 in the overlapping direction (Y-axis direction in the figure) where the side portion 36 and the end portion 22 overlap. The extent to which the penetration portion 32 reaches within the end portion 22 can be adjusted by the output of the laser used for welding. If the penetration portion 32 penetrates the end portion 22 in the overlapping direction, it can cause crack formation in the end portion 22, while if it only reaches a small part of the end portion 22, the physical and electrical connections become unstable. Therefore, there is an appropriate range for the extent to which the penetration portion 32 reaches within the end portion 22. For example, the size dii of the penetration portion 32 formed within the end portion 22 in the overlapping direction should be 10% or more and 90% or less of the total length di of the end portion 22 in the overlapping direction. In the example in the figure, the size dii of the penetration portion 32 in the overlapping direction is 50% of the total length di of the end portion 22 in the overlapping direction.

[0070] [Manufacturing method] Next, the manufacturing method of the inductor 100 described above will be explained with reference to Figure 9. Figure 9 is a flowchart showing the manufacturing method of an inductor according to an embodiment.

[0071] In the manufacturing method of the inductor 100, first, the magnetic core 10 is formed by pressure molding (step S101). This formation of the magnetic core 10 is carried out by pressure molding a compacted magnetic core, enclosing a coil element 20 that has been pre-processed to have the embedded portion 21 wound and the end portion 22 extended. After step S101, a step is performed in which the end portion 22 exposed from the magnetic core 10 is bent along the side portion 12 (step S102). After that, electrode members 30 are attached to each of the two side portions 12 (step S103).

[0072] Subsequently, a step (step S104) is performed in which the electrode member 30 and the end portion 22 are welded together by overlapping laser welding. In this way, an inductor 100 is manufactured in which the flexible electrode member 30 is fixed to the magnetic core 10 via an adhesive layer 30c and connected to the coil element 20 via a penetration portion 32. Since the electrode member 30 is overlapped and welded after the end portion 22 is bent in this inductor 100, there is no load on the joining material or cracks caused by the difference in bending characteristics between the end portion 22 and the electrode member 30, compared to a method in which the end portion 22 and the electrode member 30 are joined together and then bent. In other words, since the end portion 22 and the electrode member 30 are bent in separate steps and then joined by welding, there is no need to consider the difference in bending characteristics.

[0073] Furthermore, since the electrode member 30 is attached after the end portion 22 is bent, the electrode member 30 can be accurately attached after confirming the position of the end portion 22 after bending. Also, even after the electrode member 30 is attached, the relative position between the end portion 22 and the electrode member 30 can be estimated with high accuracy using the non-overlapping portion 22b. Subsequently, a penetration portion 32 exposed to the outside of the electrode member 30 is formed by welding from the outside of the electrode member 30. Since this penetration portion 32 can be seen from the outside of the inductor 100, it is possible to estimate, for example, that the welding is not sufficient due to insufficient output, from the size, color, shape, etc. of the penetration portion 32.

[0074] Thus, according to the manufacturing method of the inductor 100 in this embodiment, the alignment of the end portion 22 of the coil element 20 and the electrode member 30, and the accuracy of the welding between the end portion 22 and the electrode member 30 can be ensured by multiple estimation means. As a result, an inductor with a stable electrical connection is manufactured.

[0075] Furthermore, as described above, when the manufactured inductor 100 is mounted on the circuit board 99, the magnetic core 10 and the electrode member 30 behave as a single unit. Therefore, even when vibrations are applied, stress concentration in each part between the electrode member 30 fixed to the circuit board 99 and the magnetic core 10 and end 22 of the inductor 100 is mitigated, and damage to the inductor 100 is suppressed, thus maintaining the electrical connection. As a result, an inductor 100 with high seismic resistance and higher reliability is manufactured.

[0076] [Effects, etc.] As described above, the inductor 100 according to this embodiment comprises a magnetic core 10 having a three-dimensional shape and a side surface 12, a coil element 20 having a metal material, an embedded portion 21 embedded in the magnetic core 10, and an end portion 22 exposed from the magnetic core 10 and extending along the side surface 12, and a flexible electrode member 30 having a metal material, the electrode member 30 being positioned on the opposite side from the magnetic core 10 with the end portion 22 of the coil element 20 in between, the electrode member 30 having a side portion 36 positioned along the side surface 12 of the magnetic core 10, and having a side portion 36 that overlaps at least a part with the end portion 22 of the coil element 20 when viewed from the thickness direction of the side portion 36, the electrode member 30 and the magnetic core 10 are bonded together via an adhesive layer 30c containing an adhesive resin, and the electrode member 30 and the end portion 22 are welded together in at least a part of the region where the side portion 36 and the end portion 22 overlap when viewed from the thickness direction of the side portion 36.

[0077] In such an inductor 100, when mounted on a circuit board 99, the magnetic core 10 and the electrode member 30 behave as a single unit. Therefore, even when vibrations are applied, stress concentration in each part between the electrode member 30 fixed to the circuit board 99 and the magnetic core 10 and end 22 of the inductor 100 is mitigated, suppressing damage to the inductor 100 and maintaining the electrical connection. In other words, the inductor 100 has high vibration resistance. Furthermore, since the electrode member 30 is flexible, it is possible to form an electrode member 30 that follows the shape of the outer contour of the magnetic core 10, allowing the electrode member 30 to make broad surface contact with the magnetic core 10. As a result, the electrical connection between the electrode member 30 and the coil element 20 is more stable. In addition, the connection between the electrode member 30 and the coil element 20 is made by welding without using solder or other bonding materials, so that other bonding materials do not get mixed into the bonding material 97 used when mounting to the circuit board 99. In other words, since the properties of the bonding material 97 are not changed, an inductor that can easily perform as specified can be realized. Therefore, an inductor 100 with various physical and electrical connection stabilization configurations and higher connection reliability can be realized.

[0078] Furthermore, for example, the side portion 36 and end portion 22 of the electrode member 30 may have a penetration portion 32 that is integrated by welding.

[0079] According to this method, the electrode member 30 and the coil element 20 are stably connected via the penetration portion 32 formed by welding. This enables a stronger physical connection compared to cases where other joining materials such as soldering are used. Therefore, an inductor 100 with higher connection reliability can be realized.

[0080] Furthermore, for example, the melted portion 32 formed within the end portion 22 may be 90% or less in size relative to the end portion 22 in the overlapping direction where the side portion 36 and the end portion 22 overlap.

[0081] According to this, the electrode member 30 and the coil element 20 are stably connected without the penetration portion 32 passing through the end portion 22 in the overlapping direction. Therefore, an inductor 100 with higher connection reliability can be realized.

[0082] Furthermore, for example, the melted portion 32 formed within the end portion 22 may be 10% or more in size relative to the end portion 22 in the overlapping direction where the side portion 36 and the end portion 22 overlap.

[0083] According to this, the fusion portion 32 is formed over a sufficiently large area that is less prone to damage, and connection instability is suppressed. In addition, factors such as DC resistance and other thermal resistances due to poor connections can be suppressed, thus reducing the possibility of abnormal heat generation associated with energization. Therefore, an inductor 100 with higher connection reliability can be realized.

[0084] Furthermore, for example, the side portion 36 and end portion 22 of the electrode member 30 may have a plurality of fusion portions 32.

[0085] According to this, the fusion portion 32 can more reliably connect the electrode member 30 and the coil element 20. For example, even if some of the multiple fusion portions 32 do not form a connection between the electrode member 30 and the coil element 20, current can still be conducted if the other portions do form a connection between the electrode member 30 and the coil element 20. Furthermore, if the fusion portions 32 have the same area, the more fusion portions there are, the larger the cross-sectional area of ​​the conductive portion can be, thus suppressing factors of thermal resistance such as DC resistance, and thus reducing the possibility of abnormal heat generation associated with current conduction. Therefore, an inductor 100 with higher connection reliability can be realized.

[0086] Furthermore, for example, the coil element 20 is made of a wire covered with an insulating coating, and the end portion 22 of the coil element 20 has an uncoated portion that is not covered with the insulating coating, and the electrode member 30 and the end portion 22 may be welded at the uncoated portion.

[0087] According to this, welding can be performed without an insulating coating made of organic materials. When organic materials are present during welding, they gasify and hinder the welding process, leading to welding errors. With the above configuration, such welding errors can be avoided, allowing for normal welding and resulting in an inductor 100 with higher connection reliability.

[0088] Furthermore, for example, the electrode member 30 may be a foil material containing copper or a copper alloy, and the thickness of the foil material may be 20 μm or more and less than 100 μm.

[0089] According to this, an inexpensive electrode material 30 with relatively high electrical conductivity can be used. Furthermore, the flexibility of the electrode material 30 can be ensured by the thickness of the material. Due to the high conductivity mentioned above, sufficient current-carrying performance can be maintained even with such foil material. Therefore, a high-performance inductor 100 can be realized with low manufacturing costs.

[0090] Furthermore, for example, the electrode member 30 may have a plated layer 30b on its surface, which is plated with tin or solder.

[0091] According to this, when mounted on the circuit board 99, an electrode member 30 can be formed that allows the bonding material 97 to easily wet and spread. Therefore, an inductor 100 that is easy to mount can be realized. In addition, since a material with high thermal resistance is selected as the material used for the plating layer 30b, the melting temperature can be easily secured in laser welding, and the electrode member 30 and the coil element 20 can be easily welded. Thus, the inductor 100 can be easily manufactured and easily mounted on the circuit board 99.

[0092] Furthermore, for example, the end portion 22 may have a non-overlapping portion 22b that does not overlap with the side portion 36 of the electrode member 30 when viewed from the thickness direction of the side portion 36.

[0093] According to this, the position of the superimposed portion 22a can be estimated from the position of the non-superimposed portion 22b. The estimated position of the superimposed portion 22a can be used, for example, for fine-tuning the welding location before welding, and for identifying welding abnormalities after welding. As a result, a properly welded inductor 100 with high connection reliability can be manufactured.

[0094] Furthermore, for example, the side surface 12 of the magnetic core 10 has a recess 12a that is concave toward the interior of the magnetic core 10 and a base portion 12b excluding the recess 12a, and the end portion 22 may be partially housed in the recess 12a, with the other portion protruding away from the magnetic core 10 by a distance of 5.00 μm or more and 100 μm or less from the base portion 12b when viewed from a direction perpendicular to the thickness direction of the side surface portion 36.

[0095] According to this, when the electrode member 30 is attached with adhesive 50, an electrode recess is formed as if being pushed out onto the surface of the end portion 22 of the coil element 20 that protrudes beyond the base portion 12a of the side surface 12, and the end portion 22 and the electrode member 30 come into contact. Since welding is performed after this contact is established, the possibility of welding errors occurring due to, for example, air being interposed between the electrode member 30 and the end portion 22 is reduced. Therefore, welding can be performed normally, and an inductor 100 with higher connection reliability can be realized.

[0096] Furthermore, for example, the other portion of the end portion 22 may have a curved shape that is convex in the direction away from the magnetic core 10 when viewed from a direction perpendicular to the thickness direction of the side portion 36.

[0097] According to this, when the electrode member 30 is attached with adhesive 50, it becomes easier to bring the electrode member 30 and the end portion 22A into surface contact compared to the above embodiment, and as a result, the possibility of welding errors occurring due to air being interposed between the electrode member 30 and the end portion is further reduced.

[0098] Furthermore, for example, the radius of curvature of the curved shape of the other part may decrease as it moves away from the furthest point from the magnetic core 10 along the curved shape.

[0099] According to this, when the electrode member 30 is attached with adhesive 50, it becomes easier to bring the electrode member 30 and the end portion 22A into surface contact compared to the above embodiment, and as a result, the possibility of welding errors occurring due to air being interposed between the electrode member 30 and the end portion is further reduced.

[0100] Furthermore, for example, the three-dimensional shape of the magnetic core 10 may have a top surface 14 that intersects with the side surface 12, and the electrode member 30 may have a top surface portion 33 arranged along the top surface 14, connected to the side surface portion 36, and bonded to the magnetic core 10 via an adhesive layer 30c.

[0101] According to this, adhesion between the electrode member 30 and the magnetic core 10 is also achieved at the top surface 33, which extends intersecting with the side surface 36. Three-dimensional adhesion by two or more intersecting surfaces ensures a more stable connection between the electrode member 30 and the magnetic core 10. Furthermore, it is possible to suppress the detachment of the magnetic core 10 toward the top surface 14, which is difficult to suppress with the side surface 36 alone, from the top surface 14 side. Therefore, the physical connection between the electrode member 30 and the magnetic core 10 is stabilized. As a result, the physical connection between the coil element 20, which is partially embedded and fixed in the magnetic core 10, and the electrode member 30 is also stabilized, and consequently, the electrical connection between the coil element 20 and the electrode member 30 is stably maintained. Therefore, an inductor 100 with higher connection reliability can be realized.

[0102] Furthermore, for example, the three-dimensional shape of the magnetic core 10 may have a bottom surface 13 that intersects with the side surface 12 and is parallel to the top surface 14, and the electrode member 30 may have a bottom surface portion 34 that is arranged along the bottom surface 13 and is connected to the side surface portion 36.

[0103] According to this design, the magnetic core 10 and the electrode member 30 are in contact at the side surface 12 and the bottom surface 13 that intersects the side surface 12. Because the magnetic core 10 and the electrode member 30 are in three-dimensional contact, changes in their positional relationship, such as wobbling, are less likely to occur. Therefore, the positional relationship between the coil element 20, which is fixed by being partially embedded in the magnetic core 10, and the electrode member 30 is also less likely to change, thus improving the connection stability between the coil element 20 and the electrode member 30. In addition, the contact area in contact with the land 98 on the circuit board on which the inductor 100 is mounted can be increased. Thus, an inductor 100 with higher connection reliability is realized.

[0104] Furthermore, for example, the area of ​​the main surface of the top surface portion 33 along the top surface 14 may be smaller than the area of ​​the main surface of the bottom surface portion 34 along the bottom surface 13.

[0105] According to this, when the inductor 100 is moved to a predetermined land 98 on the circuit board 99 by suction and held by a nozzle, a wide flat surface for suction can be secured. Therefore, various suction nozzles can be applied, making it possible to realize an inductor 100 that is easy to mount on the circuit board 99.

[0106] (Other embodiments, etc.) The inductor relating to the embodiments of this disclosure has been described above, but this disclosure is not limited to these embodiments.

[0107] For example, electrical products or circuits using the above-described inductor are also included in this disclosure. Examples of electrical products include power supply devices equipped with the above-described inductor, and various devices equipped with said power supply devices.

[0108] Furthermore, this disclosure is not limited to this embodiment. Within the scope of one or more embodiments, various modifications to this embodiment that a person skilled in the art could conceive of, or forms constructed by combining components from different embodiments, may also be included, as long as they do not depart from the spirit of this disclosure. [Industrial applicability]

[0109] The inductor relating to this disclosure is useful as an inductor for use in various devices and equipment. [Explanation of symbols]

[0110] 10, 10x magnetic core 11, 12 Side view 12a base 12b Recess 13. Base 14 Top surface 20, 20x coil elements 21, 21x buried section 22, 22x, 22A end 22a Overlap 22b Non-superimposed area 30, 30x electrode members 30a electrode layer 30b plating layer 30c adhesive layer 32. Blended area 33 Top section 34 Bottom part 34x bottom plate 36 Side part 36x side plate 50 Adhesives 97 Bonding material 98 Rand 99 Circuit boards 100, 100x, 100A inductors

Claims

1. A magnetic core containing a magnetic material and having a three-dimensional shape with sides, A coil element comprising a metal material, having an embedded portion embedded in the magnetic core, and an end portion exposed from the magnetic core and extending along the side surface, The electrode member comprises a metal material, is flexible, and is not embedded in the magnetic core, and is positioned on the opposite side of the magnetic core from the end of the coil element, The electrode member has a side portion that is arranged along the side surface of the magnetic core, and when viewed from the thickness direction of the side portion, at least a portion of the side portion overlaps with the end of the coil element. The electrode member and the end portion are welded together in at least a portion of the area where the side portion and the end portion overlap when viewed from the thickness direction of the side portion. The side surface of the magnetic core has a recess that is concave toward the interior of the magnetic core and a base portion excluding the recess, The end portion has a surface on the magnetic core side that contacts the bottom of the recess, a portion of the end portion in the thickness direction is housed in the recess, and when viewed from a direction perpendicular to the thickness direction of the side portion, the other portion of the end portion in the thickness direction protrudes away from the base portion toward the magnetic core. The side portion has a first region that is opposite the base and is bonded to the base via an adhesive layer containing an adhesive resin, and a second region other than the first region that is opposite the recess at least through the end. The second region is positioned offset from the first region in a direction away from the side surface of the magnetic core, and the first region and the second region form an electrode recess that is concave in a direction away from the side surface of the magnetic core. The bottom of the electrode recess overlaps with the end and contacts the surface of the end opposite to the magnetic core, and is formed by bending in the direction of the first region at the boundary between the portion of the second region that is in contact with the end and the portion of the second region that is not in contact with the end. The electrode recess accommodates the end portion together with the recess. Inductor.

2. The side portion and the end portion of the electrode member have a fused portion that is integrated by welding. The inductor according to claim 1.

3. The melted portion formed within the end portion is 90% or less in size relative to the end portion in the overlapping direction where the side portion and the end portion overlap. The inductor according to claim 2.

4. The melted portion formed within the end portion is 10% or larger than the end portion in the overlapping direction where the side portion and the end portion overlap. The inductor according to claim 2 or 3.

5. The side portion and the end portion of the electrode member have a plurality of the melting portions. The inductor according to any one of claims 2 to 4.

6. The coil element consists of a wire covered with an insulating film. The end of the coil element has an uncovered portion that is not covered by the insulating film, The electrode member and the end portion are welded together in the uncovered portion. An inductor according to any one of claims 1 to 5.

7. The electrode member is a foil material containing copper or a copper alloy. The thickness of the foil material is 20 μm or more and less than 100 μm. The inductor according to any one of claims 1 to 6.

8. The electrode member has a plated layer on its surface, which is plated with tin or solder. The inductor according to any one of claims 1 to 7.

9. The end portion has a non-overlapping portion that does not overlap the side portion of the electrode member when viewed from the thickness direction of the side portion. The inductor according to any one of claims 1 to 8.

10. The other portion of the end portion protrudes from the base portion by a distance of 5.00 μm or more and 100 μm or less when viewed from a direction perpendicular to the thickness direction of the side portion, away from the magnetic core. An inductor according to any one of claims 1 to 9.

11. The other part of the end portion has a curved shape that is convex in the direction away from the magnetic core when viewed from a direction perpendicular to the thickness direction of the side portion. The inductor according to claim 10.

12. The radius of curvature of the curved shape of the other part of the end decreases as the distance from the magnetic core increases along the curved shape, starting from the furthest point. The inductor according to claim 11.

13. The three-dimensional shape of the magnetic core has a top surface that intersects with the side surface, The electrode member has a top surface portion arranged along the top surface, which is connected to the side surface portion and is bonded to the magnetic core via an adhesive layer containing an adhesive resin. The inductor according to any one of claims 1 to 12.

14. The three-dimensional shape of the magnetic core has a bottom surface that intersects with the side surface and is parallel to the top surface. The electrode member has a bottom portion that is arranged along the bottom surface and has a bottom portion that is connected to the side portion. The inductor according to claim 13.

15. The area of ​​the main surface of the top portion along the top surface is smaller than the area of ​​the main surface of the bottom portion along the bottom surface. The inductor according to claim 14.

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