inductor

Abstract

To provide an inductor capable of increasing reliability.SOLUTION: A inductor 100 includes: a magnetic core 10 that has a bottom surface 11, a top surface 12 and a side face 13c connected to the bottom surface 11 and the top surface 12; a coil element that has a coil part 21 embedded in the magnetic core 10 and a lead-out part 22 pulled out of the magnetic core 10; and a plate-like electrode member 30 placed on the side face 13c and electrically connected to the coil element via the lead-out part 22. The electrode member 30 has a side plate part 32 located along the side face 13c from which the lead-out part 22 is drawn out and a cylindrical portion 35 having a cylindrical axis extending in a direction intersecting the side face 13c. The side plate part 32 penetrates the side plate portion 32 in a thickness direction and has a through opening 33 connected to the inside of the cylindrical part 35. The lead-out part 22 passes through the through opening 33 and is in contact with the inside of the cylindrical portion 35. The cylindrical portion 35 is welded to the lead-out part 22.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to inductors. [Background technology]

[0002] Inductors are passive elements that store electrical energy as magnetic energy and are used, for example, in DC-DC converter devices for the purposes of increasing or decreasing power supply voltage and smoothing direct current. Inductors are mounted on the surface of a circuit board, for example. For example, Patent Document 1 discloses an inductor that includes a main body containing a magnetic material, a coil element disposed inside the main body, and a terminal metal fitting connected to the coil element. In the inductor described in Patent Document 1, the tip of the coil element is exposed from the main body, and a terminal metal fitting is welded to the exposed tip of the coil element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-243685 Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above, an object of the present disclosure is to improve the reliability of inductors. [Means for solving the problem]

[0005] An inductor according to one aspect of the present disclosure comprises a magnetic core having a bottom surface, a top surface, and side surfaces connected to the bottom surface and the top surface, a coil element having a coil portion embedded in the magnetic core and a draw-out portion connected to an end of the coil portion and drawn out from the side surface to the outside of the magnetic core, and a plate-shaped electrode member arranged on the side surface and electrically connected to the coil element via the draw-out portion, wherein the electrode member has a side plate portion arranged along the side surface from which the draw-out portion is drawn out, and a cylindrical portion extending with a cylindrical axis in a direction intersecting the side surface, the side plate portion having a through opening that penetrates the side plate portion in the thickness direction and connects to the interior of the cylindrical portion, the draw-out portion penetrates the through opening and contacts the interior of the cylindrical portion, and the cylindrical portion is welded to the draw-out portion. [Effects of the Invention]

[0006] According to the present disclosure, the reliability of the inductor can be improved. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a first perspective view of an inductor according to an embodiment. [Figure 2] FIG. 2 is a second perspective view of the inductor according to the embodiment. [Figure 3] 10 is a diagram showing a state before the lead-out portion and the cylindrical portion of the inductor according to the embodiment are welded together; FIG. [Figure 4] 4 is a side view of the lead-out portion and the cylindrical portion shown in FIG. 3. FIG. [Figure 5] 5A to 5C are diagrams illustrating an example of a manufacturing process for the cylindrical portion of the inductor according to the embodiment. [Figure 6] 10 is a diagram showing a cross section of an extended portion and a cylindrical portion of an inductor according to a first modified example of the embodiment. FIG. [Figure 7] 10 is a cross-sectional view showing the lead-out portion and the cylindrical portion of the inductor according to the second modification of the embodiment. FIG. [Figure 8] 10 is a diagram showing a cross section of an extended portion and a cylindrical portion of an inductor according to a third modification of the embodiment. FIG. [Figure 9]FIG. 11 is a perspective view illustrating an overlapping portion according to a third modification of the embodiment. [Figure 10] 10 is a diagram showing a cross section of the lead-out portion and the cylindrical portion of the inductor according to the fourth modification of the embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] (Background to this disclosure) In a structure in which an electrode member is welded to the tip of a coil element, as in Patent Document 1 mentioned above, the cross-sectional area of ​​the connection portion connecting the coil element and the electrode member (hereinafter referred to as the weld portion because welding is used for this connection) becomes small, which can reduce the reliability of the connection between the coil element and the electrode member. Furthermore, in a structure in which an electrode member is welded to the tip of a coil element, the cross-sectional area of ​​the current path at the welded portion cannot be increased, which increases the direct current resistance and reduces the reliability of the inductor. Furthermore, if the cross-sectional area of ​​the current path at the welded portion cannot be increased, the temperature rises when current is applied to the inductor, which reduces the reliability of the inductor.

[0009] The present disclosure has the following configuration to improve the reliability of an inductor. Hereinafter, the embodiments will be described in more detail with reference to the drawings.

[0010] Note that the embodiments described below each illustrate a specific example of the present disclosure. The numerical values, shapes, materials, components, component placement positions, connection configurations, steps, and step sequences shown in the following embodiments are examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not recited in independent claims are described as optional components.

[0011] Furthermore, in this specification, terms indicating the relationship between elements, such as parallelism, terms indicating the shape of elements, such as rectangular parallelepiped, and numerical ranges are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about a few percent.

[0012] In addition, each drawing is a schematic diagram in which emphasis, omission, or adjustment of proportions has been appropriately made to illustrate the present disclosure, and is not necessarily an exact illustration, and may differ from the actual shape, positional relationship, and proportion. In each drawing, substantially the same configuration is assigned the same reference numeral, and duplicated explanations may be omitted or simplified.

[0013] Each figure also shows the X-axis, Y-axis, and Z-axis, which represent three mutually orthogonal directions, and these axes and the axial directions along these axes are used as necessary for explanation. Note that each axis is added for explanation purposes only and does not limit the direction or posture in which the inductor is used.

[0014] Furthermore, in this specification, the terms "top surface" and "bottom surface" in the configuration of an inductor do not refer to the top surface (the surface on the vertically upper side) and bottom surface (the surface on the vertically lower side) in absolute spatial recognition, but are used as terms defined by the relative positional relationship of the components of the inductor.

[0015] (Embodiment) [Inductor configuration] The configuration of an inductor according to an embodiment will be described below: An inductor is a passive element that stores electrical energy flowing through a coil element as magnetic energy.

[0016] Fig. 1 is a first perspective view of an inductor 100 according to an embodiment. Fig. 2 is a second perspective view of the inductor 100. Note that the upper drawing in Fig. 1 shows an overall view of the inductor 100, and the lower drawing shows an enlarged perspective view of the lead-out portion 22 and the tubular portion 35 of the inductor 100.

[0017] As shown in Figures 1 and 2, the inductor 100 comprises a magnetic core 10, a coil element having a coil portion 21 and multiple lead portions 22, multiple electrode members 30 which are external terminals, and welded portions which connect the lead portions 22 and the electrode members 30.

[0018] In the following explanation, the positive half of the X-axis in inductor 100 will be mainly described, but the negative half of the X-axis in inductor 100 has the same structure as the positive half of the X-axis in inductor 100, and the same explanation applies.

[0019] The approximate outer shape of inductor 100 is determined by the shape of magnetic core 10, which is, for example, a rectangular parallelepiped powder magnetic core. Magnetic core 10 can be molded into any shape. That is, depending on the shape of magnetic core 10 during molding, inductor 100 of any shape can be realized. Magnetic core 10 of this embodiment has, for example, dimensions in the X-axis direction of 17 mm or more, dimensions in the Y-axis direction of 17 mm or more, and dimensions in the Z-axis direction of 7 mm or more.

[0020] The magnetic core 10 is the outer shell of the inductor 100 and covers a portion of the coil element (coil portion 21). The magnetic core 10 includes a magnetic material, for example, a powder magnetic core made of a metal magnetic powder and a resin material. The magnetic core 10 may be formed using any magnetic material. The magnetic material may be ferrite or other magnetic materials. The metal magnetic powder is a particulate material having a predetermined element composition, such as an Fe-Si-Al-based, Fe-Si-based, Fe-Si-Cr-based, or Fe-Si-Cr-B-based material. The resin material is selected from materials such as silicone-based resins that can maintain a certain shape by binding the metal magnetic powder particles while insulating them from each other.

[0021] The magnetic core 10 has, for example, a rectangular parallelepiped shape. The magnetic core 10 has a bottom surface 11, a top surface 12 facing away from the bottom surface 11, and four side surfaces 13a, 13b, 13c, and 13d connected to the bottom surface 11 and the top surface 12. The side surfaces 13a and 13b are aligned in the X-axis direction and face each other back to back. The side surfaces 13c and 13d are aligned in the Y-axis direction and face each other back to back. The bottom surface 11, the top surface 12, and the side surfaces 13a, 13b, 13c, and 13d are each substantially flat planes. The pair of the bottom surface 11 and the top surface 12, the pair of the side surfaces 13a and 13b, and the pair of the side surfaces 13c and 13d are each pairs of surfaces that are in a parallel positional relationship. The bottom surface 11 and the top surface 12 extend in directions that intersect with the side surfaces 13a, 13b, 13c, and 13d, specifically in directions that are perpendicular to each other. The side surfaces 13a and 13b extend in directions that intersect with the side surfaces 13c and 13d, specifically in directions that are perpendicular to each other.

[0022] The coil element has a coil portion 21 made of a single wire embedded in magnetic core 10, and multiple lead portions 22 that correspond to both ends of the wire and are exposed to the outside of magnetic core 10. In other words, the coil element according to the embodiment is composed of one coil portion 21 and two lead portions 22. In FIG. 1, the embedded coil portion 21 is indicated by a dashed line.

[0023] The coil element is composed of, for example, a conductor wire. The conductor wire is composed of a metal wire 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 made of metals or alloys and other substances, and an insulating coating that covers the metal wire. Specifically, the conductor wire is, for example, a copper wire covered with an insulating coating. The coil portion 21 and the lead-out portion 22 are names given to respective portions formed, for example, by processing a single member made of the same material.

[0024] The coil portion 21 is a portion covered by the magnetic core 10. The coil portion 21 is made of a wound conductor and functions as a coil. The number of turns of the coil portion 21 is not particularly limited and may be selected appropriately, for example, from 0.5 to 10 turns, depending on the performance required of the inductor 100 and constraints such as the size of the magnetic core 10. The cross section of the conductor constituting the coil portion 21 is, for example, a rectangular wire with each side measuring 3.5 mm × 2.5 mm. The coil portion 21 may also be made of a rectangular or round wire with an aspect ratio of 1:1. The coil portion 21 is wound vertically with the surfaces including the long sides of the cross sections of the conductor overlapping. The coil portion 21 is embedded in the magnetic core 10 so that the winding axis of the coil portion 21 is aligned along the direction connecting the bottom surface 11 and the top surface 12 (the Z-axis direction).

[0025] Coil portion 21 has an end portion (not shown) that connects from the wound portion to side surface 13c of magnetic core 10. One end of coil portion 21 is located on the positive side of the X axis, which is closer to the right of the winding axis, when viewed from a direction perpendicular to side surface 13c, and the other end is located on the negative side of the X axis, which is closer to the left of the winding axis. Furthermore, when viewed from a direction perpendicular to side surface 13c, the end of coil portion 21 is located at a height closer to bottom surface 11 than the center of side surface 13c, and both ends have the same height from bottom surface 11.

[0026] Lead-out portion 22 is connected to an end of coil portion 21 and extends outward from side surface 13c of magnetic core 10. Specifically, lead-out portion 22 is led out in a direction perpendicular to side surface 13c from a position closer to bottom surface 11 than the center of side surface 13c. Lead-out portion 22 is led out from one side surface 13c of four side surfaces 13a to 13d.

[0027] Fig. 3 is a diagram showing the state before the drawn-out portion and the cylindrical portion of the inductor are welded. Fig. 4 is a cross-sectional view of the drawn-out portion and the cylindrical portion shown in Fig. 3 as seen from the side. In this example, "viewed from the side" means viewed from the X-axis direction perpendicular to the side surface 13a. Fig. 4 shows the drawn-out portion 22 and the cylindrical portion 35 as seen from the side, as a cross-sectional view taken along a center line passing through the center of the drawn-out portion 22.

[0028] 3 and 4 has a rectangular cross section. At least a portion of the insulating coating is removed from the lead portion 22 so that the lead portion 22 can be electrically connected to the electrode member 30. The lead portion 22 passes through a through-opening 33 in a side plate portion 32 of the electrode member 30 (described later) and is in contact with the inside of the tube portion 35 (the inner surface facing the space surrounded by the tube).

[0029] As shown in FIG. 1, the electrode members 30 are disposed on the outside of the magnetic core 10 (for example, on the bottom surface 11 side, side surface 13c side, and other side surface 13d side) and are electrically connected to the lead portions 22 via welds. An electrode member 30 is provided corresponding to each of the two lead portions 22. The electrode members 30 include a conductive material and are formed, for example, of a metal material plate. The metal material plate is formed of a metal material selected from metals such as aluminum, copper, silver, and gold, alloys containing one or more of these metals, and materials composed of a metal or alloy and another substance.

[0030] The electrode member 30 has a bottom plate portion 31 arranged on the bottom surface 11 side of the magnetic core 10, a side plate portion 32 connected to the bottom plate portion 31 and arranged on the side surface 13c side of the magnetic core 10, and a tubular portion 35 protruding outward from the side plate portion 32.

[0031] The electrode member 30 also has a locking portion 38 that is connected to the bottom plate portion 31 and is arranged on the other side surface 13d of the magnetic core 10. The bottom plate portion 31, the side plate portion 32, the locking portion 38, and the plurality of tubular portions 35 are names given to respective portions that are formed, for example, by processing a single member made of the same material.

[0032] The bottom plate portion 31 is disposed on the bottom surface 11 side of the magnetic core 10 so as to extend along the bottom surface 11. The bottom plate portion 31 may be fixed to the magnetic core 10 via an adhesive. When the inductor 100 is mounted on the circuit board, the bottom plate portion 31 is joined to the circuit board by soldering. Note that the bottom plate portion 31 may have a portion that protrudes outward from the magnetic core 10 when viewed from the top surface 12 side (when viewed in a plan view in the Z-axis direction). This is preferable because when soldering in a reflow furnace, the protruding portion can be easily heated by preheating the reflow furnace, improving solderability.

[0033] Side plate portion 32 is arranged to correspond to one side surface 13c of four side surfaces 13a to 13d of magnetic core 10. Side plate portion 32 is connected to bottom plate portion 31, arranged along side surface 13c of magnetic core 10, and extends from bottom plate portion 31 toward top surface 12. Side plate portion 32 also has a through opening 33 that penetrates side plate portion 32 in the thickness direction.

[0034] The through opening 33 is, for example, rectangular, and the lead portion 22 described above is inserted into the through opening 33. The through opening 33 is connected to the interior of the cylindrical portion 35, and the lead portion 22 inserted into the through opening 33 reaches the interior of the cylindrical portion 35. When viewed from the X-axis direction, the side plate portion 32 contacts the side surface 13c of the magnetic core 10. However, this is not limited thereto and the side plate portion 32 may be disposed with a gap from the side surface 13c. In other words, the side plate portion 32 may be disposed apart from the side surface 13c. This configuration will be described in a modified example. When the side plate portion 32 contacts the side surface 13c of the magnetic core 10, it may be fixed to the magnetic core 10 via an adhesive. In this embodiment, the through opening 33 is preferably rectangular so that the lead portion 22, from which the rectangular wire used in the coil element is drawn, can be inserted. In particular, this embodiment employs a processing method in which the through opening 33 and the cylindrical portion 35 are formed in a single process. This processing method will be described with reference to FIG. 5.

[0035] 5 is a flowchart illustrating the process of forming the cylindrical portion. FIG. 5 shows how a metal material plate 502 is processed before it becomes the side plate portion 32 and the cylindrical portion 35. First, the metal material plate 502 is placed on a die 501, and the positions where the through opening 33 and the cylindrical portion 35 are to be formed are aligned with the position of a punch 503 (S101). Then, the punch 503 is pressed in the direction of the outline arrow (between the two dies 501), thereby deforming the metal material plate 502 in a direction intersecting the plate surface (S102). In the inductor 100, the portions supported by the die 501 become the side plate portion 32, and the portion pressed into the punch 503 becomes the cylindrical portion 35.

[0036] However, at this point, the pressed-in portion has a cylindrical shape with a bottom, so the unnecessary portion at the bottom must be cut off. In this embodiment, first, punch 503 is removed, and material 504 (corresponding to lead-out portion 22) is inserted (S103). Then, with support jig 505 in contact, cutter 506 is moved in the direction of the outline arrow to cut (cut) the unnecessary portion (S104). In this manner, it is possible to simultaneously form through opening 33 and cylindrical portion 35. This type of processing is also known as "drawing." In this manner, the integrally formed through opening 33 and the internal shape of cylindrical portion 35 are related. Furthermore, since lead-out portion 22 contacts the inside of cylindrical portion 35 to form an electrical connection between the coil element and electrode member 30, it is preferable that the shape of through opening 33 and the cross-sectional shape of the wire used for the coil element approximately match from the viewpoint of electrical conductivity. On the other hand, if a round wire is used for the coil element, a circular through opening may be provided.

[0037] The cylindrical portion 35 is a portion that protrudes outward from the side plate portion 32. The multiple cylindrical portions 35 cover a space, for example, in the shape of a rectangular prism, in which the shape of the through opening 33 extends in a direction perpendicular to the side surface 13c. For this reason, in this example, the cylindrical portions 35 are provided in a shape that is approximately a rectangular prism. In this way, the cylindrical portions 35 have an appropriate shape so as to cover the space that matches the shape of the through opening 33. However, the external shape of the cylindrical portions 35 does not have to match the shape of the space that they cover. For example, the external shape of the cylindrical portions that cover the cylindrical space may be a rectangular prism to match the circular cross-section of an extraction portion from which a coil element using a round wire is extracted.

[0038] As described above, in this example, the cylindrical portion 35 protrudes outward from the side plate portion 32. However, the protruding direction of the cylindrical portion is not limited thereto. For example, the cylindrical portion 35 may protrude inward from the side plate portion 32 toward the side surface 13c of the magnetic core 10. In this case, the lead-out portion 22 first contacts the interior of the cylindrical portion 35 and passes through the cylindrical portion to reach the through opening 33. In this specification, the term "an object passing through an object" refers to an opening connecting one end of the object to the other end, including a state in which the object passes through one end and is visible from the other end (i.e., a state in which the object reaches the inside of the opening). The electrode member 30 and the lead-out portion 22 are welded to the through opening 33, or in other words, the base of the cylindrical portion 35, which corresponds to the boundary with the side plate portion 32. In this example, the cylindrical portion 35 is disposed between the side plate portion 32 and the side surface 13c, so that the side plate portion 32 and the side surface 13c are spaced apart. The advantages of providing such a gap will be described later in the modified example.

[0039] The tubular portion 35 rises from the entire periphery of the boundary region between the side plate portion 32 and the through opening 33, intersects with the side surface 13c of the magnetic core 10, and protrudes in a direction away from the side surface 13c. For example, the tubular portion 35 is disposed perpendicular to the side plate portion 32 or along the extension direction of the lead portion 22. For example, the tip end of the tubular portion 35 protruding from the side plate portion 32 (the end of the tubular portion 35 farthest from the side surface 13c) may protrude further than the tip end of the lead portion 22 (the end of the lead portion 22 farthest from the side surface 13c) before the tubular portion 35 and the lead portion 22 are welded together. In other words, the tip end of the lead portion 22 is closer to the side surface 13c than the tip end of the tubular portion 35.

[0040] In this embodiment, a weld is formed at least at a location where the tip of the drawn-out portion 22 and the tip of the tubular portion 35 are in contact with or close to each other (see FIG. 1 ). This weld is formed by welding the drawn-out portion 22 and the tubular portion 35 together. For example, the weld is composed of a plurality of weld marks ws formed by laser seam welding. When viewed from the Y-axis direction, the plurality of weld marks ws are connected along the direction in which the outer periphery of the drawn-out portion 22 extends. All of the plurality of weld marks ws may be continuously connected, or some of the weld marks ws may be continuously connected. Alternatively, adjacent weld marks ws may be continuously connected so as to overlap each other. By welding the tubular portion 35 to the drawn-out portion 22, the tubular portion 35 and the drawn-out portion 22 are electrically connected (conductive) via the weld. If the tip of the drawn portion 22 were farther from the side surface 13c than the tip of the cylindrical portion 35, it would be necessary to irradiate the laser from all directions within the XZ plane in order to weld the entire circumference of the drawn portion 22. In this embodiment, the tip of the drawn portion 22 is closer to the side surface 13c than the tip of the cylindrical portion 35, and therefore welding can be performed along the entire circumference of the drawn portion 22 from the Y-axis direction, which is advantageous in terms of manufacturing man-hours.

[0041] As described above, in this embodiment, lead-out portion 22 of the coil element passes through through-opening 33 of side plate portion 32 and comes into contact with tubular portion 35, which is welded to lead-out portion 22. Furthermore, the same applies to the configuration in which tubular portion 35 is disposed between side plate portion 32 and side surface 13c, where lead-out portion 22 of the coil element reaches through-opening 33 of side plate portion 32 and comes into contact with tubular portion 35, which is welded to lead-out portion 22.

[0042] This allows the length of the welded portion formed by welding the tubular portion 35 and the lead portion 22 to be increased. This allows the cross-sectional area of ​​the welded portion connecting the coil element and the electrode member 30 to be increased, thereby improving the reliability of the connection between the coil element and the electrode member 30. Furthermore, since the cross-sectional area of ​​the current path at the welded portion can be increased, DC resistance can be reduced, and the reliability of the inductor can be improved. Furthermore, since the cross-sectional area of ​​the current path at the welded portion can be increased, temperature increases when current is applied to the inductor can be suppressed, and the reliability of the inductor can be improved. Furthermore, since the lead portion 22 is inserted into the through opening 33 and the tubular portion 35, the possibility of the magnetic core 10, together with the lead portion 22, falling off from the electrode member 30 is reduced.

[0043] Next, the locking portion 38 of the electrode member 30 will be described.

[0044] In the following explanation, we will mainly describe the negative half of the X-axis in inductor 100, but the positive half of the X-axis in inductor 100 has a similar structure to the negative half of the X-axis inductor 100, and the same explanation applies.

[0045] As shown in FIG. 2, the electrode member 30 has a locking portion 38 along the side surface 13d. More specifically, the locking portion 38 is connected to the bottom plate portion 31 and is arranged along the side surface 13d of the magnetic core 10. The locking portion 38 extends from the bottom plate portion 31 toward the top surface 12 and is arranged between the tip of the protrusion 131d, which is the outermost of the side surfaces 13d of the magnetic core 10 when viewed from the X-axis direction, and the innermost part of the side surfaces 13d. The locking portion 38 is arranged corresponding to one of the four side surfaces 13d. An opening 38a is formed in the locking portion 38. The opening 38a is a rectangular through-hole that penetrates the electrode member 30 in the thickness direction (here, the Y-axis direction). The opening 38a corresponds to the protrusion 131d formed on the side surface 13d, and the locking portion 38 is arranged so that the protrusion 131d penetrates the opening 38a. The locking portion 38 may be fixed to the magnetic core 10 via an adhesive. Such locking portion 38 is used to fix the magnetic core 10 and the electrode member 30 by locking the side surface of the protrusion 131d on the top surface 12 side with the inner surface of the opening 38a on the top surface 12 side (facing the bottom surface 11 side). In other words, the electrode member 30 is fixed to the magnetic core 10 by locking the protrusion 131d with the locking portion 38, welding at the welded portion, and (possibly by bonding the bottom plate portion 31, the side plate portion 32, and the locking portion 38). For example, as shown in the figure, such a protrusion 131d is formed closer to the bottom surface 11 than the center of the magnetic core 10. In this way, the magnetic core 10 having the protrusion 131d and the electrode member 30 having the locking portion 38 can firmly fix the electrode member 30 and the magnetic core 10.

[0046] [Inductor manufacturing method] Next, a description will be given of a method for manufacturing the above-described inductor 100. The inductor according to the embodiment is manufactured as follows. Note that the method for manufacturing the inductor 100 is not limited to the following example.

[0047] In the manufacturing method of the inductor 100, a step of pressure molding the magnetic core 10 together with the coil element is first carried out. This step is carried out by placing the coil element having the coil portion 21 in a molding die and pressure molding the powder magnetic core. The pressure during pressure molding is, for example, 5 ton / cm. 2 The heat curing temperature is, for example, 185° C. After pressure molding, exposed lead portion 22 that is not covered by magnetic core 10 protrudes, for example, perpendicular to side surface 13 c of magnetic core 10. Lead portion 22 is irradiated with, for example, a laser beam, and the insulating coating is removed.

[0048] Next, a step of preparing the electrode member 30 having the bottom plate portion 31, the side plate portion 32, the cylindrical portion 35, and the locking portion 38 by punching, drawing, and bending a metal material plate is performed.

[0049] Next, the electrode member 30 is placed on the magnetic core 10 as shown in FIG. 1 . First, the lead portion 22 is inserted into the through opening 33 of the side plate portion 32, and the side plate portion 32 is placed along the side surface 13c of the magnetic core 10. Then, the bottom plate portion 31 is bent so that it fits along the bottom surface 11 of the magnetic core 10. Then, the locking portion 38 is bent so that it fits along the other side surface 13d of the magnetic core 10. At this time, the lead portion 22 is inserted into the through opening 33 of the side plate portion 32, and the lead portion 22 comes into contact with the protrusion 35. Furthermore, the protrusion 131d is inserted into the opening 38a of the locking portion 38. Furthermore, if any or all of the bottom plate portion 31, side plate portion 32, and locking portion 38 of the electrode member 30 are to be bonded to the magnetic core 10, a thermosetting adhesive that is viscous when uncured is applied to the contact area between the electrode member 30 and the magnetic core 10 in this step. The adhesive is not cured in this step, but is cured in a later step, which will be described later.

[0050] Next, a process is performed in which the cylindrical portion 35 and the lead portion 22 are welded together by laser seam welding or the like. Specifically, a laser beam is continuously irradiated from the negative side in the Y-axis direction toward the tip of the cylindrical portion 35 and the tip of the lead portion 22, and a weld is formed along the direction in which the outer peripheries of the cylindrical portion 35 and the lead portion 22 extend when viewed from the Y-axis direction. The weld mark ws formed in the weld is circular, and is formed, for example, by rotating the laser beam spot at a predetermined radius.

[0051] Next, the electrode member 30 is bent so that the locking portions 38 of the electrode member 30 lock onto the protrusions 131d of the magnetic core 10. In this step, as shown in FIG. 1, when the magnetic core 10 is pressure-molded, a bottom surface recess 11a that is recessed toward the inside of the magnetic core 10 may be formed in advance at a position of the bottom surface 11 that overlaps with the bottom plate portion 31, and the bottom plate portion 31 may be bent so that it fits into this bottom surface recess 11a. As a result, as shown in FIGS. 1 and 2, a bottom surface crimped portion 31a is formed in the bottom plate portion 31, and the electrode member 30 is narrowed. By narrowing the electrode member 30 in this manner, the entire electrode member 30 is fastened to the magnetic core 10, and the locking portions 38 of the electrode member 30 are firmly locked onto the protrusions 131d of the magnetic core 10, thereby firmly fixing the electrode member 30 to the magnetic core 10. Furthermore, when the electrode members 30 and the magnetic core 10 are bonded together, a heat treatment is carried out after this step to harden the adhesive. In this manner, the inductor 100 is manufactured.

[0052] [First Modification of the Embodiment] An inductor according to Modification 1 of the embodiment will be described below. Fig. 6 is a diagram showing a cross section of the lead-out portion and the cylindrical portion of the inductor according to Modification 1 of the embodiment.

[0053] The inductor of this example differs from the above-described embodiment in that the side plate portions 32 are not in contact with the side surface 13c of the magnetic core 10. More specifically, in this inductor, the side plate portions 32 are spaced apart from the side surface 13c on the top and bottom sides of the through-hole 33. By spaced apart from the side surface 13c, heat generated from the melted portion during laser welding is prevented from being transferred to the side surface 13c via the cylindrical portion 35 and the side plate portions 32. Heat generated during welding can easily affect the resin material contained in the magnetic core 10 and, in some cases, can change the properties of the magnetic core 10. However, by spaced apart from the side surface 13c as described above, the possibility of such adverse effects can be reduced. Also, in FIG. 6B, a heat dissipation jig 90 is attached to the inductor shown in FIG. 6A. The heat dissipation jig 90 is a tool made of metal or the like with a relatively high thermal conductivity, and by being inserted into the space between the side plate portion 32 and the side surface 13c, it can remove and dissipate heat from the side plate portion 32. The heat dissipation jig 90 is, for example, a metal plate such as a titanium plate. By separating the side plate portion 32 and the side surface 13c to provide a gap in this manner, it is also possible to insert the heat dissipation jig 90 into the space between the side plate portion 32 and the side surface 13c before laser seam welding and reduce the effect of heat on the magnetic core 10.

[0054] [Modification 2 of the embodiment] An inductor according to Modification 2 of the embodiment will be described below. Fig. 7 is a diagram showing a cross section of the lead-out portion and the cylindrical portion of the inductor according to Modification 2 of the embodiment.

[0055] The inductor of this example differs from the above-described first modification in that a portion of the side plate portion 32 closer to the top surface 12 than the through opening 33 is inclined toward the magnetic core 10. More specifically, in the inductor of this example, on the top surface 12 side of the side plate portion 32 closer to the through opening 33, the distance between the side plate portion 32 and the side surface 13c decreases the further the side plate portion 32 is from the through opening 33. The end of the side plate portion 32 on the top surface 12 side is in contact with the magnetic core 10. This configuration has the effect of making it difficult for heat generated during welding to be transmitted to the magnetic core 10, while preventing foreign matter such as dust from entering the space between the side plate portion 32 and the side surface 13c, and increasing the number of contact points between the magnetic core 10 and the side plate portion 32, thereby improving vibration resistance.

[0056] [Third Modification of the Embodiment] An inductor according to a third modification of the embodiment will be described. Fig. 8 is a diagram showing a cross section of the lead-out portion and the cylindrical portion of the inductor according to the third modification of the embodiment. Fig. 9 is a perspective view for explaining the overlapping portion according to the third modification of the embodiment. Note that in Fig. 9, the magnetic core 10 and the coil elements are omitted in order to clarify the shape of the overlapping portion 37.

[0057] The inductor of this example differs from the first modification in that it includes an overlapping portion 37 that overlaps the side plate portion 32. More specifically, in this example, the inductor includes an electrode member 30 disposed between the side plate portion 32 and the side surface 13c, and includes an overlapping portion 37 that overlaps the side plate portion 32, and a connecting portion 36 that is connected to the side plate portion 32 and the overlapping portion 37 on the top surface 12 side of the through opening 33. The connecting portion 36 and the overlapping portion 37 are integrated with the side plate portion 32, the cylindrical portion 35, and the like as part of the electrode member 30. The overlapping portion 37 can also be said to be connected to the side plate portion 32 via the connecting portion 36. As shown in FIG. 9 , the portion of the overlapping portion 37 that overlaps the through opening 33 is hollow. Therefore, even if the overlapping portion 37 is present between the side plate portion 32 and the side surface 13c, the lead portion 22 drawn from the side surface 13c can reach the through opening 33.

[0058] As for the shape of the overlapping portion 37, as shown in (a) of Figure 9, an overlapping through opening 33a is provided at a position overlapping with the through opening 33, making the portion overlapping with the through opening 33 hollow. However, as shown in (b) of Figure 9, a cutout portion 33b may be provided at a position overlapping with the through opening 33, or the overlapping portion 37 may be long enough not to reach the through opening 33, as shown in (c) of Figure 9.

[0059] By providing such overlapping portion 37, as in the inductor according to Modification 2, it is possible to prevent foreign matter such as dust from entering the space between side plate portion 32 and side surface 13c, and to increase the number of contact points between magnetic core 10 and side plate portion 32, thereby improving vibration resistance. Furthermore, although overlapping portion 37 may come into local contact with magnetic core 10, a long heat transfer distance can be ensured before reaching overlapping portion 37 via connection portion 36, and therefore the heat generated during welding can be dissipated from electrode member 30 itself, thereby reducing the thermal impact on magnetic core 10.

[0060] [Fourth Modification of the Embodiment] An inductor according to Modification 4 of the embodiment will be described below. Fig. 10 is a diagram showing a cross section of the lead-out portion and the cylindrical portion of the inductor according to Modification 4 of the embodiment.

[0061] The inductor of this example differs from the above-described first modification in that the portion of the side plate portion 32 closer to the bottom surface 11 than the through opening 33 is inclined toward the magnetic core 10. More specifically, in the inductor of this example, the distance between the side plate portion 32 and the side surface 13c becomes smaller on the bottom surface 11 side than the through opening 33, as the portion becomes farther away from the through opening 33. The end of the side plate portion 32 on the bottom surface 11 side is in contact with the magnetic core 10. More specifically, the connection portion between the side plate portion 32 and the bottom plate portion 31 and the connection portion between the side surface 13c and the bottom surface 11 are in contact with each other.

[0062] This makes it possible to obtain the effect of making it difficult for heat generated during welding to be transmitted to magnetic core 10, while increasing the number of contact points between magnetic core 10 and side plate portion 32, thereby improving vibration resistance.

[0063] [Effects, etc.] As described above, the inductor 100 according to this embodiment comprises a magnetic core 10 having a bottom surface 11, a top surface 12, and side surfaces 13c connected to the bottom surface 11 and the top surface 12; a coil element having a coil portion 21 embedded in the magnetic core 10 and a lead-out portion 22 connected to an end of the coil portion 21 and drawn out from the side surface 13c to the outside of the magnetic core 10; and a plate-shaped electrode member 30 arranged on the side surface 13c and electrically connected to the coil element via the lead-out portion 22. The electrode member 30 has a side plate portion 32 arranged along the side surface 13c from which the lead-out portion 22 is drawn out, and a cylindrical portion 35 extending with a cylindrical axis in a direction intersecting the side surface 13c. The side plate portion 32 penetrates the side plate portion 32 in the thickness direction and has a through opening 33 connected to the interior of the cylindrical portion 35. The lead-out portion 22 penetrates the through opening 33 and contacts the interior of the cylindrical portion 35. The cylindrical portion 35 is welded to the lead-out portion 22.

[0064] This allows the lead portion 22 to penetrate the side plate portion 32 and reach the tubular portion 35. As a result, movement of the lead portion 22 in a direction along the plate surface of the side plate portion 32 is restricted. In other words, movement of the magnetic core 10 in which the coil portion 21 is embedded, including the coil portion 21 connected to the lead portion 22, in a direction along the plate surface is restricted, thereby preventing the magnetic core 10 from falling off the electrode member 30. Furthermore, the lead portion 22 contacts the tubular portion 35, and a weld is formed at the contact point to electrically connect the coil element and the electrode member 30. Because the lead portion 22 reaches the inside of the tubular portion 35, a wide contact area can be formed between the inner surface of the tubular portion 35 and the side surface of the lead portion 22. In particular, because the lead portion 22 is nested within the tubular portion 35 when viewed from the extension direction of the tubular portion 35, a weld can be formed around the entire circumference of the lead portion 22 at maximum. As a result, the range in which the weld is formed can be expanded. That is, the cross-sectional area of ​​the current path at the welded portion can be increased, thereby suppressing problems such as temperature rise when current is passed through the inductor 100. In this way, the inductor 100 according to this embodiment can further improve the reliability of the inductor 100.

[0065] Furthermore, for example, the side plate portion 32 may be disposed closer to the top surface 12 than the through opening 33 and spaced apart from the side surface 13c.

[0066] This makes it possible to reduce the amount of heat conducted from the welding point through side plate portion 32 to magnetic core 10 via side surface 13c when electrode member 30 and the coil element are welded together. Furthermore, heat dissipation jig 90 for dissipating heat generated during welding can be disposed between this separated side surface 13c and side plate portion 32, further enhancing the effect of reducing the amount of heat conducted from side surface 13c to magnetic core 10.

[0067] Furthermore, for example, the electrode member 30 may have an overlapping portion 37 that is arranged between the side plate portion 32 and the side surface 13c and overlaps the side plate portion 32, and a connection portion 36 that is connected to the side plate portion 32 and the overlapping portion 37 on the top surface 12 side of the through opening 33.

[0068] This allows heat during welding to be conducted between the side surface 13c and the side plate portion 32, from the side plate portion 32 to the connection portion 36, and from the connection portion 36 to the overlapping portion 37. The connection portion and the overlapping portion 37 increase the total heat capacity of the electrode member 30 itself and can also increase the heat dissipation effect, thereby further enhancing the effect of reducing the amount of heat conducted from the side surface 13c to the magnetic core 10.

[0069] Furthermore, for example, the distance between the side plate portion 32 and the side surface 13c may become smaller as the side plate portion 32 moves away from the through opening 33 on the top surface 12 side relative to the through opening 33.

[0070] According to this, when the electrode member 30 and the coil element are welded together, there is a possibility that foreign matter such as dust may enter the separation space provided to reduce the amount of heat conducted from the welded point through the side plate portion 32 and from the side surface 13c to the magnetic core 10, but by reducing the separation distance on the top surface 12 side in this separation space, it is possible to make it difficult for such foreign matter to enter. Furthermore, if the side plate portion 32 is in contact with the magnetic core 10, the number of contact points between the magnetic core 10 and the side plate portion 32 can be increased, thereby improving the vibration resistance of the inductor 100.

[0071] Furthermore, for example, the side plate portion 32 may be disposed closer to the bottom surface 11 than the through opening 33 and spaced apart from the side surface 13c.

[0072] This makes it possible to reduce the amount of heat conducted from the welded portion through the side plate portion 32 and the side surface 13c to the magnetic core 10 when the electrode member 30 and the coil element are welded together.

[0073] Also, for example, the electrode member 30 may have an overlapping portion 37 arranged between the side plate portion 32 and the side surface 13c, overlapping the side plate portion 32, and a connection portion 36 connected to the side plate portion 32 and the overlapping portion 37 on the top surface 12 side of the through opening 33, and the overlapping portion 37 may have an overlapping through opening 33a overlapping with the through opening 33.

[0074] This allows the overlapping portion 37 to be expanded toward the bottom surface 11 from the through opening 33, thereby further increasing the effect of expanding the total heat capacity of the electrode member 30 itself and the effect of expanding the heat dissipation function by providing the overlapping portion 37.

[0075] Furthermore, for example, the distance between the side plate portion 32 and the side surface 13c may become smaller as the side plate portion 32 moves away from the through opening 33 on the bottom surface 11 side relative to the through opening 33.

[0076] This makes it difficult for side plate portion 32 to vibrate relative to magnetic core 10, thereby improving the vibration resistance of inductor 100. In particular, if the end portion of side plate portion 32 on the bottom surface 11 side is in contact with magnetic core 10, that is, if the connection portion between side plate portion 32 and bottom plate portion 31 and the connection portion between side surface 13c and bottom surface 11 are in contact with each other, the number of contact points between magnetic core 10 and side plate portion 32 increases, and the improvement in the vibration resistance of inductor 100 can be further improved.

[0077] Also, for example, the end of the lead-out portion 22 farthest from the side surface 13c may be closer to the side surface 13c than the end of the tubular portion 35 farthest from the side surface 13c.

[0078] This allows welding to be performed so that the wall of the tubular portion 35 is supplied as a melting point to the surface of the end side of the drawn portion 22 when viewed from the predetermined direction in which the tubular portion 35 extends. In other words, since welding can be performed in one direction from the above-mentioned predetermined direction, the number of steps required for welding can be reduced.

[0079] (Other embodiments, etc.) While the inductors and the like according to the embodiments and modifications of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and modifications. As long as they do not deviate from the gist of the present disclosure, various modifications that would occur to a person skilled in the art to the embodiments and modifications, as well as other forms constructed by combining some of the components of the embodiments and modifications, are also included within the scope of the present disclosure.

[0080] In the above embodiment, the bottom plate portion 31, the side plate portion 32, the tubular portion 35, and the locking portion 38 of the electrode member 30 are formed by processing a single member made of the same material, but this is not limiting. For example, the electrode member 30 may be formed by connecting the bottom plate portion 31, the side plate portion 32, the tubular portion 35, and the locking portion 38, which are made of different members.

[0081] In the above embodiment, the coil portion 21 and the lead-out portion 22 of the coil element are formed by processing a single member made of the same material, but this is not limiting. The coil element may be formed by connecting the coil portion 21 and the lead-out portion 22 made of different members.

[0082] In the above embodiment, the conductor wire has a rectangular cross section, but is not limited thereto. The conductor wire may have a circular cross section, and at least a portion of the lead portion 22 may be flattened to facilitate connection with the electrode member 30.

[0083] In the above embodiment, the lead-out portion 22 is drawn out from a position closer to the bottom surface 11 than the center of the side surface 13c, but this is not limiting. The lead-out portion 22 may be drawn out from a position closer to the top surface 12 than the center of the side surface 13c.

[0084] The present disclosure also includes, for example, electrical appliances or electrical circuits using the above-described inductor. Examples of electrical appliances include power supply devices equipped with the above-described inductor and various devices equipped with such power supply devices. [Industrial Applicability]

[0085] INDUSTRIAL APPLICABILITY The inductor according to the present disclosure is useful as an inductor used in various devices and equipment. [Explanation of symbols]

[0086] 10 magnetic core 11 Bottom 11a Bottom recess 12 Top 13a, 13b, 13c, 13d side 21 Coil section 22 Drawer section 30 Electrode material 31 Bottom plate part 31a Bottom caulking part 32 Side plate part 33 Through opening 33a Overlapping through opening 33b Notch 35 Cylinder part 36 Connection 37 Overlapping section 38 Locking part 38a aperture 90 Heat dissipation jig 100 inductor 131d Convex part ws welding marks

Claims

1. a magnetic core having a bottom surface, a top surface, and a side surface connected to the bottom surface and the top surface; a coil element having a coil portion embedded in the magnetic core and a lead portion connected to an end of the coil portion and led out from the side surface to the outside of the magnetic core; a plate-shaped electrode member disposed on the side surface and electrically connected to the coil element via the lead-out portion, the electrode member has a side plate portion disposed along the side surface from which the lead portion is led out, and a tubular portion having a tubular axis extending in a direction intersecting the side surface, the side plate portion has a through opening that penetrates the side plate portion in a thickness direction and is connected to the inside of the cylindrical portion, the lead-out portion passes through the through-opening and contacts the inside of the cylindrical portion; The cylindrical portion is welded to the lead-out portion. Inductor.

2. The side plate portion is disposed on the top surface side of the through opening and spaced apart from the side surface.

10. The inductor of claim 1.

3. The electrode member is an overlapping portion disposed between the side plate portion and the side surface and overlapping the side plate portion; a connecting portion connected to the side plate portion and the overlapping portion on the top surface side of the through opening; 3. The inductor according to claim 2.

4. The side plate portion is spaced from the side surface by a distance smaller as it is spaced from the through opening on the top surface side than the through opening.

3. The inductor according to claim 2.

5. The side plate portion is disposed on the bottom side of the through opening and spaced apart from the side surface.

10. The inductor of claim 1.

6. The electrode member is an overlapping portion disposed between the side plate portion and the side surface and overlapping the side plate portion; a connection portion connected to the side plate portion and the overlapping portion on the top surface side of the through opening, The overlapping portion has an overlapping through opening that overlaps with the through opening.

6. The inductor according to claim 5.

7. The side plate portion has a bottom surface side closer to the through opening, and the distance between the side plate portion and the side surface becomes smaller as the side plate portion is farther from the through opening.

6. The inductor according to claim 5.

8. The end of the lead-out portion farthest from the side surface is closer to the side surface than the end of the cylindrical portion farthest from the side surface. The inductor according to any one of claims 1 to 7.

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