Inductors and electrical products

Abstract

To provide an inductor that is easier to operate properly. [Solution] The inductor 100 comprises a three-dimensional magnetic core 10 having a top surface 14 and a bottom surface 13 facing the circuit board 151 when mounted on the circuit board 151, a coil element 20 having an embedded portion 21 embedded in the magnetic core 10 and a coil end 22 exposed from the magnetic core 10 and extending along the side surface 12 of the magnetic core 10, and an electrode member 30 joined to the coil end 22. The electrode member 30 is a copper-based metal foil with a thickness of less than 100 μm and has a side plate 36 arranged along the side surface 12 of the magnetic core 10 and having a side plate joining portion 36b joined to the coil end 22, and a bottom plate 34 arranged along the bottom surface 13 of the magnetic core 10. An insulating coat 140 made of an insulating material is formed on the outer periphery of the forming surface, with the top surface 14 of the magnetic core 10 as the forming surface and the upper surface being at a position higher by the thickness from the forming surface.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an inductor and an electrical product using the 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 stepping up / down a power supply voltage and smoothing a direct current. As an example of such an inductor, Patent Documents 1 and 2 disclose a surface-mount inductor mounted on a circuit board. The inductor includes a three-dimensional magnetic core containing a magnetic material, a coil element in which a winding portion of a coil is embedded in the magnetic core, and an electrode member joined to an end portion of the coil element protruding from a side surface of the magnetic core. These inductors are mounted on a circuit board by soldering the electrode members to the circuit board. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0003] PATENT DOCUMENT 1 Japanese Unexamined Patent Publication No. 2011-249770 PATENT DOCUMENT 2 International Publication No. 2022 / 091761 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0004] Conventional inductors may not be able to operate properly in some cases. In view of the foregoing, an object of the present disclosure is to provide an inductor and the like that can operate more appropriately. MEANS FOR SOLVING THE PROBLEM

[0005] An inductor according to one aspect of the present disclosure comprises a magnetic core having a three-dimensional shape including a magnetic material and having side surfaces, a top surface and a bottom surface facing the circuit board when mounted on the circuit board; a coil element including a metal material and having an embedded portion embedded in the magnetic core and a coil end exposed from the magnetic core and extending along the side surface of the magnetic core; and an electrode member including a metal material and joined to the coil end, wherein the coil end extends along the side surface of the magnetic core, the electrode member is a copper-based metal foil with a thickness of less than 100 μm and has a side plate having a side plate joining portion arranged along the side surface of the magnetic core and joined to the coil end, and a bottom plate arranged along the bottom surface of the magnetic core, and an insulating coat formed of an insulating material having an upper surface at a position higher by the thickness from the forming surface, with the top surface of the magnetic core as the forming surface.

[0006] Furthermore, an electrical product according to one aspect of the present disclosure comprises a circuit board, an inductor as described above mounted on the circuit board such that the bottom surface of the magnetic core faces the circuit board, a heat dissipation gel filled inside the insulating coat, and a heat dissipation housing provided on the opposite side of the inductor, with the heat dissipation gel in between. [Effects of the Invention]

[0007] The inductor and the like of this disclosure can be operated more appropriately. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view of an inductor according to an embodiment. [Figure 2] Figure 2 is a perspective view showing the inductor shown in Figure 1, but with its orientation reversed. [Figure 3] Figure 3 is a perspective view showing the magnetic core and coil elements of the inductor shown in Figure 1. [Figure 4] Figure 4 is a cross-sectional view of the inductor's magnetic core and coil element along the IV-IV line shown in Figure 3. [Figure 5]Figure 5 is a cross-sectional view illustrating an electrical product using an inductor according to an embodiment. [Figure 6] Figure 6 is a view of the inductor according to the embodiment, seen from the top side. [Figure 7] Figure 7 is a side view of the inductor according to the embodiment. [Figure 8] Figure 8 is a cross-sectional view of the inductor along the line VIII-VIII shown in Figure 1. [Figure 9] Figure 9 is a cross-sectional view of the inductor along the line IX-IX shown in Figure 8. [Figure 10] Figure 10 shows the first corner portion provided on the side surface of the magnetic core of the inductor, and the second corner portion provided at the coil end of the coil element. [Figure 11] Figure 11 shows the first and second bent portions provided on the side plate of the electrode member of the inductor. [Figure 12] Figure 12 is a flowchart showing a method for manufacturing an inductor according to an embodiment. [Figure 13] Figure 13 is a diagram showing the configuration of the inductor during the manufacturing process according to the embodiment. [Figure 14] Figure 14 is a schematic diagram showing various processes applied to the side plate of the electrode member of the inductor according to the embodiment. [Figure 15] Figure 15 is a schematic diagram showing the magnetic core, coil ends, and electrode members of the inductor of Comparative Example 1. [Figure 16] Figure 16 is a schematic diagram showing the magnetic core, coil ends, and electrode members of the inductor of Comparative Example 2. [Figure 17] Figure 17 is a schematic diagram showing the magnetic core, coil ends, and electrode members of the inductor of Comparative Example 3. [Figure 18] Figure 18 is a perspective view of an inductor according to a modified example of the embodiment. [Modes for carrying out the invention]

[0009] (Background leading to this disclosure) In recent years, inductors have been used in many electronic devices. Inductors are sometimes used by being mounted on a circuit board, and surface-mount inductors that are premised on mounting to lands on a circuit board have also been developed.

[0010] As a conventional inductor, for example, as disclosed in Patent Document 1, it includes a magnetic core formed of a magnetic material, a coil embedded inside the magnetic core with a terminal portion protruding from the side surface of the magnetic core, and a flat terminal that protrudes outside the magnetic core from the side surface of the magnetic core and is connected to the terminal portion of the coil. In the coil component in which the terminal portion of the coil protruding from the side surface of the magnetic core and the flat terminal are bent toward the bottom surface side of the magnetic core along the side surface of the magnetic core, an inductor in which the terminal portion of the coil is arranged between the flat terminal and the magnetic core is known.

[0011] Also, as disclosed in Patent Document 2, it includes a three-dimensional magnetic core containing a magnetic material and having a bottom surface, side surfaces and a top surface, a coil element having an embedded portion embedded in the magnetic core and a coil end exposed from the magnetic core and extending along the side surface, and an electrode member arranged on the opposite side of the magnetic core across the coil end and having a plating layer on its surface. An inductor is also known in which the electrode member has a side portion partially overlapping the coil end, the electrode member and the magnetic core are bonded via an adhesive layer, and the electrode member and the coil end are welded in at least a part of a region where the side portion and the coil end overlap.

[0012] However, in the inductor disclosed in Patent Document 1, a part of the flat terminal is embedded in the magnetic core and fixed to the magnetic core main body, and there is a gap between the magnetic core main body and the flat terminal. Therefore, when vibration is applied, shaking occurs, which causes a problem that the vibration resistance decreases.

[0013] In order to solve this problem, Patent Document 2 discloses an inductor in which an electrode member is bonded to a magnetic core. According to this inductor, when the inductor is mounted on a circuit board, the magnetic core and the electrode member behave integrally. Therefore, when vibration or the like is applied, stress concentration in each part between the electrode member fixed to the circuit board and the magnetic core and the coil end of the inductor is alleviated, and vibration resistance can be improved.

[0014] However, even the inductor disclosed in Patent Document 2 has room for improvement in terms of vibration resistance. Therefore, in view of the above, this disclosure provides an inductor that can further improve vibration resistance. Also, an inductor is a component that generates heat during operation. For this reason, it is necessary to thermally connect a heat dissipation housing with high thermal conductivity to the inductor in order to dissipate the heat generated from the inductor when it is operating. On the other hand, heat dissipation housings are often conductive, and a short circuit may occur between the inductor and the heat dissipation housing (especially between the internal coil element and the heat dissipation housing), which may result in a situation where the inductor cannot operate properly. For this reason, the inductor provided below is designed to be less prone to short circuits between the inductor and the heat dissipation housing and to operate properly. The embodiments will be described in more detail below with reference to the drawings.

[0015] The embodiments described below are all specific examples of this disclosure. The numerical values, shapes, materials, components, arrangement positions of components, connection configurations, steps, and the order of steps shown in the following embodiments are examples only and are not intended to limit this disclosure. Furthermore, any components in the following embodiments that are not described in an independent claim will be described as optional components.

[0016] Furthermore, each figure shows the X, Y, and Z axes, which represent three mutually orthogonal directions, and these axes and the axial directions along them are used for explanatory purposes as needed. Note that these axes are included for explanatory purposes only and do not limit the direction or orientation in which the inductor is used.

[0017] (Embodiment) [composition] The inductor according to the embodiment will be described with reference to Figures 1 to 11.

[0018] Figure 1 is a perspective view of an inductor according to an embodiment. Figure 2 is a perspective view of the inductor shown in Figure 1, but inverted. Figure 3 is a perspective view of the magnetic core and coil elements of the inductor shown in Figure 1. Figure 4 is a cross-sectional view of the magnetic core and coil elements of the inductor, taken along the IV-IV line shown in Figure 3. Figure 5 is a cross-sectional view illustrating an electrical product using the inductor according to an embodiment. Figure 6 is a view of the inductor according to an embodiment from the top. Figure 7 is a view of the inductor according to an embodiment from the side.

[0019] Figure 3 shows the inductor 100 with the electrode member 30 removed. In Figure 4, the hatching of the magnetic core 10 is omitted.

[0020] As shown in Figures 1 and 2, the inductor 100 according to this embodiment comprises a magnetic core 10, a coil element 20, and an electrode member 30. The inductor 100 is formed with insulating coats 130 and 140, shown by dot hatching.

[0021] 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. For example, the inductor 100 may have dimensions of 6 mm in the X-axis direction, 6 mm in the Y-axis direction, and 3 mm in the Z-axis direction.

[0022] 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.

[0023] The magnetic core 10 is, for example, a rectangular parallelepiped, and has a base surface 13, four sides connected to the base surface 13, and a top surface 14 connected to the four sides and facing away from the base 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 base surface 13.

[0024] As shown in Figures 1 to 4 and Figure 6, a magnetic core recess 12b is formed on the side surface 12, which is recessed toward the interior of the magnetic core 10. In other words, the side surface 12 is provided with the magnetic core recess 12b formed on the side surface 12 and the base portion 12a, which is the part of the side surface 12 excluding the magnetic core recess 12b. The base portion 12a is a flat portion along the side surface 12. The magnetic core recess 12b is the portion that extends into the interior of the magnetic core 10 when viewed from the base portion 12a. The magnetic core recess 12b may have a groove-like shape, or it may have a stepped shape that drops into the interior of the magnetic core 10 starting from the base portion 12a.

[0025] Figure 8 is a cross-sectional view of the inductor along the line VIII-VIII shown in Figure 1.

[0026] As shown in Figure 8, the magnetic core recess 12b has an inner bottom surface 12b1 which is the inner bottom of the magnetic core recess 12b, and an inner wall surface 12b2 which connects the base 12a and the inner bottom surface 12b1. The inner bottom surface 12b1 is parallel to the side surface 12 of the magnetic core 10. The inner wall surface 12b2 has an inclined surface that is inclined with respect to the inner bottom surface 12b1 and the base 12a. The magnetic core recess 12b tapers towards the inner bottom surface 12b1 in the direction from the side surface 12 to the inner bottom surface 12b1. In other words, the opening of the magnetic core recess 12b widens as it moves from the inner bottom surface 12b1 towards the side surface 12.

[0027] As shown in Figures 3 and 4, the magnetic core recess 12b extends toward the top surface 14 and reaches the top surface 14, with the top surface 14 side of the magnetic core recess 12b being open. In this embodiment, the magnetic core recess 12b is composed of one inner bottom surface 12b1 and three inner wall surfaces 12b2. The direction in which the magnetic core recess 12b extends toward the top surface 14 is the same direction as the mold removal direction after the magnetic core 10 has been formed. The coil end 22 of the coil element 20 is located inside the magnetic core recess 12b.

[0028] As shown in Figures 4 and 6, the coil element 20 has an embedded portion 21 embedded in the magnetic core 10 and a plurality of coil ends 22 connected to the embedded portion 21. The coil element 20 of this embodiment is composed of one embedded portion 21 and two coil ends 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 coil ends 22 are names given to the respective parts formed by processing a single member made of the same material.

[0029] The coil end 22 is the portion that is not covered by the magnetic core 10 and is exposed from the magnetic core recess 12b. The coil end 22 is flat and extends along the side surface 12 toward the top surface 14 (i.e., along the Z-axis direction) (see Figures 3 and 4). Specifically, the coil end 22 protrudes from the magnetic core recess 12b and extends along the inner bottom surface 12b1 of the magnetic core recess 12b, and is terminated before reaching the top surface 14. In other words, the coil end 22 is positioned in the magnetic core recess 12b so as not to protrude from the magnetic core recess 12b toward the positive Z-axis direction.

[0030] As shown in Figure 8, the coil end 22 has an outer end surface 22f1 that contacts the side plate joint 36b, an inner end surface 22f2 that faces away from the outer end surface 22f1 and towards the inner bottom surface 12b1 of the magnetic core recess 12b, and an outer end surface 22s that connects to the outer end surface 22f1 and the inner end surface 22f2, respectively. The coil end 22 may be in contact with the inner bottom surface 12b1 of the magnetic core recess 12b, or it may be positioned with a gap between it and the inner bottom surface 12b1. Note that the magnetic core recess 12b is not an essential component. For example, even if the inductor is made of a magnetic core with flat sides without a magnetic core recess 12b, the above effect of making the inductor 100 easier to use can be obtained if it has the insulating coating configuration described later.

[0031] The buried portion 21 shown in Figures 4 and 6 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. For example, in the inductor 100, the cross-section of the copper wire constituting the buried portion 21 is circular with a diameter of 0.4 mm and an aspect ratio of 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 coil end 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 coil end 22 is located and is connected to the coil end 22.

[0033] The electrode member 30 shown in Figures 1 and 2 has a side plate 36 and a bottom plate 34. The side plate 36 and the bottom plate 34 are formed by bending metal foil, which is the material of the electrode member 30.

[0034] The electrode member 30 is made of a material selected from metallic materials such as aluminum, copper, silver, and gold, as well as alloys consisting of metals and other substances. For example, in the inductor 100 in this embodiment, a copper-based electrode member 30 including copper or a copper alloy is selected.

[0035] The insulating coatings 130 and 140 are sheet-like members formed from materials that do not have conductivity, in other words, materials that have insulating properties. The insulating coatings 130 and 140 are formed, for example, by applying an insulating material dissolved in a solvent to a sheet and curing it by evaporating the solvent. The insulating coatings 130 and 140 are formed from, for example, acrylic resin and epoxy resin.

[0036] As shown in Figure 4, the insulating coating 140 is formed on the outer periphery of the top surface 14 of the magnetic core 10, with the top surface 14 serving as the forming surface. Here, the outer periphery refers to the area extending inward by a predetermined width W1 from the outer periphery of the top surface 14 of the magnetic core 10 (i.e., each end in the Y-axis direction). In practice, as shown in Figure 1, the outer periphery corresponds to both ends in the X-axis direction and both ends in the Y-axis direction, forming an area that encircles the outer periphery of the top surface 14 of the magnetic core 10.

[0037] The insulating coat 140 has an upper surface (the positive side in the Z-axis direction) that is positioned higher than the top surface 14 of the magnetic core 10, which is the surface on which the insulating coat is formed, by a thickness T1. Conversely, in the inductor 100, the top surface 14 of the magnetic core 10 is lower than the upper surface of the insulating coat 140. Since the insulating coat 140 is formed in a region of a predetermined width W1 from the outer circumference, and not formed inside that region, a space (recess) is formed consisting of the top surface 14 of the magnetic core 10, which is lower than the upper surface of the insulating coat 140.

[0038] Here, Figure 5 shows a cross-sectional view of an electrical product 150 using the inductor 100 from the same viewpoint as in Figure 4. As shown in Figure 5, when the inductor 100 is used in the electrical product 150, it is mounted so that the bottom surface 13 of the magnetic core 10 of the inductor 100 faces the circuit board 151 of the electrical product 150. Specifically, the electrode member 30 of the inductor 100 is electrically and physically connected to a land (not shown) formed on the circuit board 151 using solder (which becomes a solder fillet in the state of the electrical product 150).

[0039] Furthermore, since the inductor 100 is a component that generates heat, a heat dissipation housing 152 is thermally connected to it via a heat dissipation gel or the like to dissipate the heat generated. The heat dissipation gel is a fluid substance such as silicone resin that is filled into the space formed inside the insulating coat 140. The heat dissipation housing 152 is a component such as a fin or heat pipe made of a metal material with high thermal conductivity. Although metal materials with high thermal conductivity such as aluminum and copper are used for the heat dissipation housing 152, these materials are also conductive. Therefore, if the heat dissipation housing 152 comes into direct contact with the top surface 14 of the magnetic core 10, a short circuit may occur between the heat dissipation housing 152 and the coil element 20 of the inductor 100.

[0040] In this embodiment, the inductor 100 has an insulating coating 140 on the outer circumference of the top surface 14 of the magnetic core 10. Therefore, even when the heat dissipation housing 152 is pressed towards the inductor 100, the distance between the inductor 100 and the heat dissipation housing 152 is maintained by the insulating material by the thickness T1 of the insulating coating 140. As a result, short circuits like the one described above are less likely to occur, and the inductor 100 is more likely to operate properly. Thus, by providing the insulating coating 140 on the top surface 14 of the magnetic core 10, it is possible to obtain the effect of properly operating the inductor 100.

[0041] To achieve this effect, the insulating coating 140 is given a predetermined width W1 and thickness T1 so that a constant distance is maintained even when the heat dissipation housing 152 is pressed toward the top surface 14 of the magnetic core 10. The predetermined width W1 should be, for example, 0.1 mm or more so that the heat dissipation housing 152 is not easily crushed when pressed. However, if the predetermined width W1 is made too large, the amount of heat dissipation gel filling will decrease, and the heat conducted from the inductor 100 to the heat dissipation housing 152 will decrease. For this reason, the predetermined width W1 should be no more than 1 / 4 the length of the width W3 of the forming surface. This allows at least the inner half of the width W3 of the forming surface to be used for thermal connection to the heat dissipation housing 152. The width W3 of the forming surface generally matches the width of the magnetic core 10 (dimensions in the X-axis direction and the Y-axis direction), but in the cross-sections shown in Figures 4 and 5, it is shorter by the amount of the magnetic core recess 12b. For this reason, the predetermined width W1 may be partially changed according to the magnetic core recess 12b.

[0042] Furthermore, the thickness T1 of the insulating coating 140 should be, for example, 0.01 mm or more. This allows for a gap of at least 0.01 mm between the heat dissipation housing 152 and the top surface 14 of the magnetic core 10, thereby reducing the likelihood of short circuits. On the other hand, the thickness T1 of the insulating coating 140 should be, for example, 0.2 mm or less. If an insulating coating 140 with a thickness greater than 0.2 mm is provided, the process for achieving that thickness may become complicated. Therefore, from the viewpoint of ease of forming the insulating coating 140, it is appropriate to set an upper limit on the thickness T1 as described above.

[0043] Furthermore, the insulating coating 140 is continuously formed not only on the top surface 14 of the magnetic core 10, but also on parts of the sides 11 and 12 connected to the top surface 14. In other words, the insulating coating 140 can ensure a creepage distance from the heat dissipation housing 152 according to the height H1 of the portion formed on the sides 11 and 12. This makes the effect of making short circuits less likely to occur more pronounced. The height H1 here is such that, for example, when forming the insulating coating 140, the insulating coating 140 reaches the sides 11 and 12 only by operation (e.g., application) from the top surface 14 side of the magnetic core 10. From the viewpoint of ensuring a creepage distance, the height H1 should be 0.1 mm or more. Also, from the viewpoint of the operation of forming the insulating coating 140, the height should be no more than 1 / 4 the length of the height H3 of the sides 11 and 12.

[0044] As shown in Figure 4, the insulating coating 130 is formed on the outer periphery of the bottom surface 13 of the magnetic core 10, with the bottom surface 13 serving as the forming surface. Here, the outer periphery refers to the area extending inward by a predetermined width W2 from the outer periphery of the bottom surface 13 of the magnetic core 10 (i.e., each end in the Y-axis direction). In practice, as shown in Figure 2, the outer periphery corresponds to both ends in the X-axis direction and both ends in the Y-axis direction, forming an area that encircles the outer periphery of the bottom surface 13 of the magnetic core 10.

[0045] The insulating coat 130 has a lower surface (the negative side in the Z-axis direction) located at a position lower than the bottom surface 13 of the magnetic core 10, which is the surface on which the insulating coat is formed, by a distance T2. Conversely, in the inductor 100, the bottom surface 13 of the magnetic core 10 is located higher than the lower surface of the insulating coat 130. The insulating coat 130 is formed in a region of a predetermined width W2 from the outer circumference, and is not formed inside this region, so a space (recess) is formed by the bottom surface 13 of the magnetic core 10, which is higher than the lower surface of the insulating coat 130. In this space, the inductor 100 is thermally connected to the circuit board 151 via a heat dissipation gel or the like. Since conductive parts such as printed patterns may be exposed on the surface of the circuit board 151, similar to the heat dissipation housing 152, if the circuit board 151 comes into direct contact with the bottom surface 13 of the magnetic core 10, a short circuit may occur between the circuit board 151 and the coil element 20 of the inductor 100.

[0046] In this embodiment, the inductor 100 has an insulating coating 130 on the outer circumference of the bottom surface 13 of the magnetic core 10. Therefore, when the heat dissipation housing 152 is pressed toward the inductor 100, the inductor 100 is pressed against the circuit board 151 in conjunction with it. However, the distance between the inductor 100 and the circuit board 151 is maintained by the insulating material by the thickness T2 of the insulating coating 130. As a result, short circuits like the one described above are less likely to occur, and the inductor 100 is more likely to operate properly. Thus, by providing the insulating coating 130 on the top surface 14 of the magnetic core 10, the effect of improving the operation of the inductor 100 can be obtained.

[0047] To achieve this effect, the insulating coating 130 is given a predetermined width W2 and thickness T2 so that a constant distance is maintained even when the bottom surface 13 of the magnetic core 10 is pressed against the circuit board 151. The predetermined width W2 should be, for example, 0.1 mm or more so that it is not easily crushed when pressed against the circuit board 151. However, if the predetermined width W2 is made too large, the amount of heat dissipation gel filling will decrease, and the heat conducted from the inductor 100 to the circuit board 151 will decrease. For this reason, the predetermined width W2 should be no more than 1 / 4 the length of the width W3 of the forming surface. This allows at least the inner half of the width W3 of the forming surface to be used for thermal connection to the circuit board 151. The width W3 of the forming surface generally coincides with the width of the magnetic core 10 (dimensions in the X-axis direction and the Y-axis direction).

[0048] Furthermore, the thickness T2 of the insulating coating 130 should be, for example, 0.01 mm or more. This allows for a gap of at least 0.01 mm between the circuit board 151 and the bottom surface 13 of the magnetic core 10, thereby reducing the likelihood of short circuits. On the other hand, the thickness T2 of the insulating coating 130 should be, for example, 0.2 mm or less. If an insulating coating 130 with a thickness greater than 0.2 mm is provided, the process for achieving that thickness may become complicated. Therefore, from the viewpoint of ease of forming the insulating coating 130, it is appropriate to set an upper limit on the thickness T2 as described above.

[0049] Furthermore, the insulating coating 130 is formed continuously not only on the bottom surface 13 of the magnetic core 10, but also on parts of the sides 11 and 12 connected to the bottom surface 13. In other words, the insulating coating 130 can ensure a creepage distance from the circuit board 151 according to the height H2 of the portion formed on the sides 11 and 12. This makes the effect of making short circuits less likely to occur more pronounced. The height H2 here is such that, for example, when forming the insulating coating 140, the insulating coating 130 reaches the sides 11 and 12 only by operation (e.g., application) from the bottom surface 13 side of the magnetic core 10. From the viewpoint of ensuring creepage distance, the height H2 should be 0.1 mm or more. Also, from the viewpoint of the operation of forming the insulating coating 130, the height should be no more than 1 / 4 the length of the height H3 of the sides 11 and 12.

[0050] The insulating coating 130 is formed before the electrode member 30 is attached. In other words, the electrode member 30 is attached after the insulating coating 130 has been formed.

[0051] The electrode member 30 is made of a flexible material, for example, a foil material having a thickness of 20 μm or more and less than 100 μm. Specifically, the thickness of the electrode member 30 in this embodiment is 50 μm. The flexibility of the electrode member 30 allows it to be bent to conform to the surface of the coil end 22 and the magnetic core 10. The flexibility of the electrode member 30 means that when the electrode member 30 is pressed against the magnetic core 10 and the coil end 22, it has the property of being able to plastically deform in accordance with the surface shape of the magnetic core 10 and the coil end 22. In other words, the electrode member 30 deforms when subjected to an external force and maintains its shape after deformation.

[0052] The electrode members 30 are provided one on each side in the Y-axis direction of the inductor 100, corresponding to each of the two coil ends 22. Here, we will describe one of the two electrode members 30, but the same description applies to the other electrode member 30 as they have the same configuration. The side plate 36 and bottom plate 34 of the electrode member 30 are designations given to the respective parts, which are formed by processing a single member made of the same material.

[0053] The side plate 36 shown in Figures 6 and 7 is a part provided along the side surface 12 of the magnetic core 10, corresponding to the side surface 12 of the magnetic core 10. The side plate 36 is positioned to overlap the base 12a and the coil end 22 of the side surface 12 of the magnetic core 10.

[0054] The side plate 36 has a side plate fixing portion 36a, a side plate joining portion 36b, and a side plate recess 36c.

[0055] The side plate fixing portion 36a is the part that is fixed to the side surface 12 of the magnetic core 10. When viewed from a direction perpendicular to the side surface 12, the side plate fixing portion 36a overlaps the base portion 12a and is fixed to the base portion 12a via an adhesive (see Figures 13 and 14). As the adhesive, for example, a resin-adhesive resin such as a thermosetting epoxy resin or a silicone resin is used.

[0056] The side plate joint 36b is the portion that is joined to the coil end 22. Figures 1 and 7 show multiple spot-shaped joining regions 40. When viewed from a direction perpendicular to the side surface 12, the side plate joint 36b overlaps the coil end 22 and is joined to the coil end 22 by, for example, laser welding.

[0057] The side plate recess 36c is connected to the side plate fixing portion 36a and the side plate joining portion 36b, and is a recessed portion that, when viewed from the side surface 12 of the magnetic core 10, is in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b. The side plate 36 has two side plate recesses 36c, and the two side plate recesses 36c are located on both sides of the coil end 22 when viewed from a direction perpendicular to the side surface 12 of the magnetic core 10. The side plate recess 36c is positioned between the inner wall surface 12b2 of the magnetic core recess 12b and the coil end 22. Furthermore, the side plate recess 36c has a shape that conforms to the shape of the outer surface of the magnetic core recess 12b and the coil end 22. For example, the side plate recess 36c is formed by applying a pressing jig 80 (see Figure 14(d)) to a part of the side plate 36 between the side plate fixing part 36a and the side plate joining part 36b, and pushing a part of the side plate 36 toward the inner bottom surface 12b1 of the magnetic core recess 12b.

[0058] As shown in Figure 8, the side plate recess 36c formed by the pressing jig 80 has an inner bottom portion 36c1 at the inner bottom of the side plate recess 36c and an inner wall portion 36c2 connecting the side plate fixing portion 36a and the inner bottom portion 36c1. The inner bottom portion 36c1 of the side plate recess 36c is substantially parallel to the side surface 12 of the magnetic core 10 and is located on the inner bottom surface 12b1 side of the magnetic core recess 12b rather than the side surface 12 and the outer end surface 22f1 of the coil end 22. The inner wall portion 36c2 has an inclined surface that is inclined with respect to the inner bottom portion 36c1 and the side plate fixing portion 36a. The side plate recess 36c is tapered in the direction from the side plate fixing portion 36a toward the inner bottom portion 36c1. The inclination angle of the inner wall portion 36c2 with respect to the inner bottom portion 36c1 is smaller than the inclination angle of the inner wall surface 12b2 with respect to the inner bottom surface 12b1.

[0059] For example, the depth dp2 of the side plate recess 36c is 0.3 times or more and 0.9 times or less of the depth dp1 of the magnetic core recess 12b. The side plate recess 36c does not contact the inner bottom surface 12b1 of the magnetic core recess 12b, and there is a predetermined gap between the side plate recess 36c and the inner bottom surface 12b1 of the magnetic core recess 12b. The side plate recess 36c is formed by bending deformation caused by pressing with the pressing jig 80, but in order to maintain the shape after deformation, it is desirable that the depth dp2 of the side plate recess 36c be 1 / 2 or more of the thickness of the electrode member 30.

[0060] Figure 9 is a cross-sectional view of the inductor along the line IX-IX shown in Figure 8. Figure 10 shows the first corner portion provided on the side surface of the magnetic core of the inductor, and the second corner portion provided at the coil end of the coil element. Figure 11 shows the first and second bends provided on the side plate of the electrode member of the inductor.

[0061] As shown in Figures 8 to 10, the magnetic core 10 has a plurality of first corners m1 located at the boundary between the side surface 12 of the magnetic core 10 and the inner wall surface 12b2 of the magnetic core recess 12b. The first corners m1 are the starting points of the step formed by the base 12a and the inner wall surface 12b2. The corners of the first corners m1 may be rounded. The plurality of first corners m1 are formed along the inner wall surface 12b2 of the magnetic core recess 12b when viewed from a direction perpendicular to the side surface 12 of the magnetic core 10 (see Figure 10). Of the plurality of first corners m1, two are formed in a direction along the side surface 12 and parallel to the axis perpendicular to the bottom surface 13 and the top surface 14. The other two first corners m1 are formed in a direction along the side surface 12 and parallel to the bottom surface 13.

[0062] As shown in Figures 8 and 10, the coil end 22 has two second corners m2 located at the boundary between the outer end surface 22f1 and the side end surface 22s. The second corners m2 are the corner portions formed by the outer end surface 22f1 and the side end surface 22s. The corner portions of the second corners m2 have a predetermined rounded shape. The second corners m2 are formed along the extension direction of the coil end 22.

[0063] As shown in Figures 8 and 11, the side plate 36 of the electrode member 30 has a first bent portion n1 at the boundary between the side plate fixing portion 36a and the side plate recess 36c, and a second bent portion n2 at the boundary between the side plate joining portion 36b and the side plate recess 36c. The first bent portion n1 and the second bent portion n2 are formed simultaneously when the pressing jig 80 is pressed into a part of the side plate 36 to form the side plate recess 36c.

[0064] The first bent portion n1 abuts against the first corner portion m1 so as to cover it. The first bent portion n1 may also be in contact with the first corner portion m1 via an adhesive (not shown). The side plate recess 36c is recessed in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b, starting from the first bent portion n1.

[0065] The second bent portion n2 abuts against the second corner portion m2 so as to cover it. The second bent portion n2 is in contact with the second corner portion m2. The side plate recess 36c is recessed in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b, starting from the second bent portion n2.

[0066] The two first corners m1 shown in Figure 8 are arranged in a direction along the side surface 12 of the magnetic core 10 and parallel to the bottom surface 13 of the magnetic core 10, that is, in a direction along the X-axis. Each of the two first bends n1 is located diagonally inward of the two first corners m1 and abuts against the two first corners m1 located diagonally outward of the two first bends n1. This arrangement of the two first corners m1 and the two first bends n1 restricts the position of the magnetic core 10 relative to the electrode member 30 in the X-axis direction. This improves the vibration resistance of the inductor 100.

[0067] Furthermore, the two second corner portions m2 shown in Figure 8 are arranged in a direction along the outer surface 22f1 of the end and perpendicular to the extension direction of the coil end 22, that is, along the X-axis direction. Each of the two second bends n2 is located diagonally outside the two second corner portions m2 and abuts against the two second corner portions m2 located diagonally inside the two second bends n2. This arrangement of the two second corner portions m2 and the two second bends n2 restricts the position of the coil end 22 relative to the electrode member 30 in the X-axis direction. As a result, the vibration resistance of the inductor 100 is improved.

[0068] The first corner portion m1 shown in Figure 9 is located on the bottom surface 13 side of the magnetic core recess 12b in a direction perpendicular to the bottom surface 13 and top surface 14 of the magnetic core 10, i.e., in the Z-axis direction. The bottom plate 34 of the electrode member 30 is in contact with the bottom surface 13 of the magnetic core 10. The first bent portion n1 and the bottom plate 34 are located outside the first corner portion m1 and the bottom surface 13, respectively, and are in contact with the first corner portion m1 and the bottom surface 13 of the magnetic core 10. This arrangement of the first corner portion m1, the first bent portion n1, the bottom surface 13 of the magnetic core 10, and the bottom plate 34 of the electrode member 30 restricts the position of the magnetic core 10 relative to the electrode member 30 in the Z-axis direction. This improves the vibration resistance of the inductor 100.

[0069] Furthermore, the position of the magnetic core 10 in the Y-axis direction is restricted by the contact between the two electrode members 30 and the two sides 12 of the magnetic core 10 when the two electrode members 30 are joined to the circuit board. This ensures the vibration resistance of the inductor 100.

[0070] The inductor 100 of this embodiment comprises a magnetic core 10 having a three-dimensional shape and containing a magnetic material, with a side surface 12, a bottom surface 13, and a top surface 14; a coil element 20 containing a metal material, having an embedded portion 21 embedded in the magnetic core 10, and a coil end 22 exposed from the magnetic core 10 and extending along the side surface of the magnetic core 10; and an electrode member 30 containing a metal material and joined to the coil end 22. The side surface 12 of the magnetic core 10 is provided with a magnetic core recess 12b that is recessed toward the interior of the magnetic core 10. The coil end 22 protrudes from the magnetic core recess 12b and extends along the inner bottom surface 12b1 of the magnetic core recess 12b. The electrode member 30 is a copper-based metal foil with a thickness of less than 100 μm and has a side plate 36 arranged along the side surface 12 of the magnetic core 10 and a bottom plate 34 arranged along the bottom surface 13 of the magnetic core 10. The side plate 36 has a side plate fixing portion 36a fixed to the side surface 12 of the magnetic core 10, a side plate joining portion 36b joined to the coil end 22, and a side plate recess 36c connected to the side plate fixing portion 36a and the side plate joining portion 36b and recessed in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b.

[0071] In this way, since the side plate recess 36c, which is part of the electrode member 30, is recessed in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b, the position of the magnetic core 10 can be restricted using the side plate recess 36c. This improves the vibration resistance of the inductor 100.

[0072] [Manufacturing method] Next, the manufacturing method of the inductor 100 described above will be explained with reference to Figures 12 to 14.

[0073] Figure 12 is a flowchart showing the manufacturing method of an inductor according to the embodiment. Figure 13 is a diagram showing the configuration in the manufacturing process of an inductor according to the embodiment. Figure 14 is a schematic diagram showing various processes applied to the side plate of the electrode member of the inductor according to the embodiment.

[0074] In the manufacturing method of the inductor 100, first, as shown in Figure 13(a), the coil element 20 is formed by winding a wire (step S101). This forms a coil element 20 having a winding portion and an end.

[0075] Next, as shown in Figure 13(b), the magnetic core 10 is molded by pressure molding (step S102). This molding of the magnetic core 10 is carried out by pressure molding the compacted magnetic core so as to enclose the winding portion of the coil element 20. Magnetic core recesses 12b are formed on the two sides 12 of the magnetic core 10. After step S102, the insulating film on the ends of the coil element 20 protruding from the magnetic core recesses 12b is removed.

[0076] Next, as shown in Figure 13(c), the end of the coil element 20 is press-formed so that it becomes flat (step S103). Next, as shown in Figure 13(d), the end of the coil element 20 is bent to follow the side surface 12 of the magnetic core 10 (step S104). This bending process positions the coil end 22 within the magnetic core recess 12b (see Figure 14(a)).

[0077] Next, as shown in Figure 13(e), an insulating coat 140 is formed on the top surface 14 and parts of the sides 11 and 12 of the magnetic core 10, and an insulating coat 130 is formed on the bottom surface 13 and parts of the sides 11 and 12 (step S105). The insulating coats 130 and 140 are formed, for example, by applying resin to the magnetic core 10 by printing and allowing the solvent to evaporate.

[0078] Next, as shown in Figure 13(f), adhesive is applied to the two sides 12 of the magnetic core 10 (step S106). The adhesive is applied to the base 12a of the magnetic core 10, for example, by printing (see Figure 14(b)).

[0079] Next, as shown in Figure 13(g), electrode members 30 are attached to each of the two sides 12 of the magnetic core 10 (step S107). In step S107, electrode members 30 that have been pre-bent and formed to have side plates 36 and bottom plates 34 are attached to the sides 12 of the magnetic core 10. This fixes the side plates 36 of the electrode members 30 to the sides 12 of the magnetic core 10 (see Figure 14(c)).

[0080] Next, as shown in Figure 13(h), a side plate recess 36c is formed in the side plate 36 (step S108). The side plate recess 36c is formed by applying a pressing jig 80 to a part of the side plate 36 between the side plate fixing part 36a and the side plate joining part 36b, and pushing the part of the side plate 36 toward the inner bottom surface 12b1 of the magnetic core recess 12b (see Figure 14(d)). This pressing by the pressing jig 80 bends and stretches a part of the side plate 36, forming the inner bottom part 36c1, the inner wall part 36c2, and the first bent part n1 and the second bent part n2 of the side plate recess 36c. The formation of this side plate recess 36c is achieved by a type of drawing process in which the pressing jig 80 is used as a punch and the magnetic core 10, including the magnetic core recess 12b, is used as a die. The two side plate recesses 36c located on both sides of the coil end 22 are formed simultaneously by the pressing jig 80. The side plate recesses 36c of each of the two electrode members 30 may be formed simultaneously by two pressing jigs 80 positioned on both outer sides of the side surface 12 of the magnetic core 10.

[0081] Next, as shown in Figure 13(i), a step (step S109) is performed in which the electrode member 30 and the coil end 22 are welded together by overlap joint laser welding. This joins the electrode member 30 to the coil end 22 (see Figure 14(e)). Through these steps, the inductor 100 is manufactured.

[0082] The method for manufacturing the inductor 100 according to this embodiment includes: an element formation step of forming a coil element 20 having a winding portion and a coil end 22; a magnetic core formation step of forming a magnetic core 10 by embedding the winding portion so that the coil end 22 protrudes from the magnetic core recess 12b when forming a rectangular parallelepiped magnetic core 10 having a magnetic core recess 12b on its side surface 12; a bending step of bending the coil end 22 so that the coil end 22 protruding from the magnetic core recess 12b is positioned within the magnetic core recess 12b; a fixing step of fixing the side plate 36 of the electrode member 30 to the side surface 12 of the magnetic core 10 so as to cover at least a portion of the coil end 22 positioned within the magnetic core recess 12b; a recess formation step of pushing a portion of the side plate 36 of the electrode member 30 into the magnetic core recess 12b to form a side plate recess 36c; and a joining step of joining the electrode member 30 to the coil end 22.

[0083] In this way, by recessing the side plate recess 36c, which is part of the electrode member 30, in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b, an inductor 100 can be manufactured in which the position of the magnetic core 10 can be restricted using the side plate recess 36c. This improves the vibration resistance of the inductor 100.

[0084] [Differences from the comparative example] The effects of the inductor according to the embodiment will be explained with reference to comparative examples. Below, the advantages of forming the electrode member 30 from a copper-based metal foil with a thickness of less than 100 μm will be explained. Note that Comparative Example 1 shown below is prior art, but Comparative Examples 2 and 3 are examples presented for comparison with this embodiment and are not prior art.

[0085] Figure 15 is a schematic diagram showing the magnetic core, coil ends, and electrode members of the inductor of Comparative Example 1.

[0086] The electrode member 30x of the inductor 100x in Comparative Example 1 is flat and does not have a side plate recess like the electrode member 30 of the inductor 100 in the embodiment. In the inductor 100x of Comparative Example 1, the flat electrode member 30x is bonded to the magnetic core 10, but it is difficult to further improve vibration resistance with this configuration.

[0087] Figure 16 is a schematic diagram showing the magnetic core, coil ends, and electrode members of the inductor of Comparative Example 2.

[0088] Comparative Example 2 shows an example in which the electrode member 30x has a thickness of 150 μm. In Comparative Example 2, after bonding the side plate 36x of the electrode member 30x to the side surface 12 of the magnetic core 10, a portion of the side plate 36x of the electrode member 30x is pressed in to form a concave side plate recess 36cx. However, the side plate 36x, which has a thickness of 150 μm, has higher rigidity and lower flexibility than the side plate 36 of the metal foil (in this embodiment), which has a thickness of 50 μm. Therefore, in Comparative Example 2, when a portion of the side plate 36x is pressed in starting from the corner mx of the magnetic core 10 to form the side plate recess 36cx, the pressing force is also transmitted to the side plate fixing portion 36ax, and there is a risk that the adhesion between the side plate fixing portion 36ax and the side surface 12 will come undone. In addition, in Comparative Example 2, when a portion of the side plate 36x is pressed in, the coil end 22 may be deformed, and there is a risk that laser welding in the subsequent process cannot be performed stably.

[0089] Figure 17 is a schematic diagram showing the magnetic core, coil ends, and electrode members of the inductor of Comparative Example 3.

[0090] Comparative Example 3 shows an example in which the side plate recess 36cx is formed before attaching the electrode member 30x to the side surface 12 of the magnetic core 10, and the side plate 36x with the side plate recess 36cx formed thereon is attached to the side surface of the magnetic core 10. However, when fitting the pre-formed side plate recess 36cx into the magnetic core recess 12b, a clearance is required between the corner mx and the bent portion nx to insert the side plate recess 36cx. Therefore, in Comparative Example 3, a clearance is created between the corner mx and the bent portion nx, making it difficult to further improve vibration resistance. In addition, in Comparative Example 3, due to variations in the thickness of the coil end 22 or the thickness of the adhesive, a gap may be created between the outer surface 22f1x of the coil end 22 and the side plate joint 36bx, which may make it difficult to perform laser welding stably in subsequent processes.

[0091] In contrast, in the inductor 100 of this embodiment, the electrode member 30 is made of copper-based metal foil with a thickness of less than 100 μm. Therefore, a side plate recess 36c can be easily formed by plastically deforming a part of the side plate 36 starting from the corner of the boundary between the side surface 12 of the magnetic core 10 and the magnetic core recess 12b. With this configuration, for example, when the inductor 100 is subjected to lateral and vertical vibrations, the side plate recess 36c acts to catch on the magnetic core recess 12b, etc. This improves the vibration resistance of the inductor 100.

[0092] Furthermore, the electrode member 30 is made of copper-based metal foil with a thickness of less than 100 μm, and has lower rigidity and higher flexibility than the coil end 22, so it is possible to form the side plate recess 36c while suppressing damage to the coil end 22. In addition, good contact can be maintained between the outer surface 22f1 of the coil end 22 and the side plate joint 36b, allowing for stable laser welding in subsequent processes.

[0093] [Modified examples of the embodiment] An inductor according to a modified embodiment will be described with reference to Figure 18. In this modified embodiment, an example will be described in which the magnetic core recess 12b is configured by a single step.

[0094] Figure 18 is a perspective view of an inductor according to a modified example of the embodiment.

[0095] As shown in Figure 18, the inductor 100 according to a modified embodiment comprises a magnetic core 10, a coil element 20, and an electrode member 30. The configuration of the coil element 20 in the modified embodiment is the same as in the embodiment.

[0096] In the modified example, the magnetic core 10 differs from the embodiment in that the magnetic core recess 12b has a stepped shape. The magnetic core recess 12b in the modified example is a single step that drops into the interior of the magnetic core 10, starting from the base 12a.

[0097] The magnetic core recess 12b has an inner bottom surface 12b1 which is the inner bottom of the magnetic core recess 12b, and an inner wall surface 12b2 which connects the base 12a and the inner bottom surface 12b1. The inner bottom surface 12b1 is parallel to the side surface 12 of the magnetic core 10. The inner wall surface 12b2 has an inclined surface that is inclined with respect to the inner bottom surface 12b1 and the base 12a. In the modified example, the base 12a is provided on the bottom surface 13 side of the coil end 22.

[0098] The magnetic core recess 12b has an opening on the top surface 14 side. The magnetic core recess 12b also extends to each of the two sides 11 of the magnetic core 10 and reaches both sides 11, and the magnetic core recess 12b has an opening on both sides 11. In the modified example, the magnetic core recess 12b is composed of one inner bottom surface 12b1 and one inner wall surface 12b2. The coil end 22 of the coil element 20 is placed in the magnetic core recess 12b.

[0099] The electrode member 30 is composed of a side plate 36 and a bottom plate 34.

[0100] The side plate 36 is a portion provided to correspond to the side surface 12 of the magnetic core 10 and to be positioned along the side surface 12. The side plate 36 is positioned to overlap the base 12a and the coil end 22 of the side surface 12 of the magnetic core 10.

[0101] The side plate 36 has a side plate fixing portion 36a, a side plate joining portion 36b, and a side plate recess 36c. The side plate fixing portion 36a is the part that is fixed to the side surface 12 of the magnetic core 10. The side plate joining portion 36b is the part that is joined to the coil end 22.

[0102] In the modified example, the side plate recess 36c is connected to the side plate fixing portion 36a and the side plate joining portion 36b, and is a recessed portion that, when viewed from the side surface 12, is in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b. The side plate recess 36c is formed on both sides of the coil end 22 when viewed from a direction perpendicular to the side surface 12 of the magnetic core 10. The side plate recess 36c is shaped to conform to the shape of the outer surface of the magnetic core recess 12b and the coil end 22. For example, the side plate recess 36c is formed by applying a pressing jig 80 to a part of the side plate 36 in a region different from the side plate fixing portion 36a and the side plate joining portion 36b, and pushing the part of the side plate 36 in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b.

[0103] The side plate recess 36c has an inner bottom portion 36c1 located at the inner bottom of the side plate recess 36c, and an inner wall portion 36c2 connecting the side plate fixing portion 36a and the inner bottom portion 36c1. The inner bottom portion 36c1 of the side plate recess 36c is substantially parallel to the side surface 12 of the magnetic core 10, and is located on the inner bottom surface 12b1 side of the magnetic core recess 12b, rather than the side surface 12 and the outer end surface 22f1 of the coil end 22. The inner wall portion 36c2 has an inclined surface.

[0104] The coil end 22 has two second corners m2 located at the boundary between the outer end surface 22f1 and the side surface 22s of the end. The second corners m2 are formed along the extension direction of the coil end 22. The side plate 36 of the electrode member 30 has a second bend n2 at the boundary between the side plate joint 36b and the side plate recess 36c. The second bend n2 abuts against the second corner so as to cover the second corner m2. The side plate recess 36c is recessed in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b, starting from the second bend n2.

[0105] The two second corner portions m2 are arranged in a direction along the outer surface 22f1 of the end and perpendicular to the extension direction of the coil end portion 22, i.e., along the X-axis direction. Each of the two second bend portions n2 is located diagonally outside the two second corner portions m2 and abuts against the two second corner portions m2 located diagonally inside the two second bend portions n2. This arrangement of the two second corner portions m2 and the two second bend portions n2 restricts the position of the coil end portion 22 with respect to the electrode member 30 in the X-axis direction. This improves the vibration resistance of the inductor 100.

[0106] The first corner portion m1 is located on the bottom surface 13 side of the magnetic core recess 12b in a direction perpendicular to the bottom surface 13 and top surface 14 of the magnetic core 10, i.e., in the Z-axis direction. The bottom plate 34 of the electrode member 30 is in contact with the bottom surface 13 of the magnetic core 10. The first bent portion n1 and the bottom plate 34 are located outside the first corner portion m1 and the bottom surface 13, respectively, and are in contact with the first corner portion m1 and the bottom surface 13 of the magnetic core 10. This arrangement of the first corner portion m1, the first bent portion n1, the bottom surface 13 of the magnetic core 10, and the bottom plate 34 of the electrode member 30 restricts the position of the magnetic core 10 relative to the electrode member 30 in the Z-axis direction. This improves the vibration resistance of the inductor 100.

[0107] Furthermore, the position of the magnetic core 10 in the Y-axis direction is restricted by the contact between the two electrode members 30 and the two sides 12 of the magnetic core 10 when the two electrode members 30 are joined to the circuit board. This ensures the vibration resistance of the inductor 100.

[0108] In this modified example, the side plate recess 36c, which is part of the electrode member 30, is recessed in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b, so that the position of the magnetic core 10 can be restricted using the side plate recess 36c. This improves the vibration resistance of the inductor 100.

[0109] (summary) An example of an inductor 100 according to one embodiment of this disclosure is provided below.

[0110] The inductor 100 of Example 1 comprises a magnetic core 10 having a three-dimensional shape including a magnetic material and side surfaces 11 and 12, a top surface 14, and a bottom surface 13 that faces the circuit board 151 when mounted on the circuit board 151; a coil element 20 including a metal material and having an embedded portion 21 embedded in the magnetic core 10, and a coil end 22 that is exposed from the magnetic core 10 and extends along the side surface 12 of the magnetic core 10; and an electrode member 30 including a metal material that is joined to the coil end 22, wherein the coil end 22 is on the side of the magnetic core 10 The electrode member 30 is a copper-based metal foil with a thickness of less than 100 μm and is arranged along the side surface 12 of the magnetic core 10. It has a side plate 36 having a side plate joint portion 36b that is joined to the coil end 22 and is arranged along the side surface 12 of the magnetic core 10, and a bottom plate 34 arranged along the bottom surface 13 of the magnetic core 10. An insulating coat 140 made of an insulating material is formed on the outer periphery of the forming surface, with the top surface 14 of the magnetic core 10 being the forming surface, and the upper surface being positioned higher by the thickness from the forming surface.

[0111] Thus, the inductor 100 is provided with an insulating coat 140 with a thickness T1 that is higher than the top surface 14 of the magnetic core 10 on the outer circumference. When a heat dissipation gel is filled inside the insulating coat 140 and the heat dissipation housing 152 is pressed down on top of it, a gap of thickness T1 is created between the heat dissipation housing 152 and the top surface 14 of the magnetic core 10, while still allowing the heat dissipation housing 152 and the top surface 14 to be thermally connected. As a result, the heat generated from the inductor 100 is dissipated to the heat dissipation housing 152, allowing the inductor 100 to operate appropriately thermally. On the other hand, when such a heat dissipation configuration is adopted, the heat dissipation housing 152 is less likely to come into contact with the top surface 14, so it is possible to suppress the occurrence of a short circuit between the coil element 20 of the inductor 100 and the heat dissipation housing 152. Therefore, when the operation of the inductor 100 is appropriately controlled thermally using the heat dissipation housing 152, it is possible to suppress the occurrence of a short circuit and allow the inductor 100 to operate appropriately.

[0112] The inductor 100 of Example 2 is the inductor described in Example 1, wherein the side surface 12 of the magnetic core 10 is provided with a magnetic core recess 12b that is recessed toward the interior of the magnetic core 10, the coil end 22 protrudes from the magnetic core recess 12b and extends along the inner bottom surface 12b1 of the magnetic core recess 12b, and the side plate 36 has a side plate fixing portion 36a fixed to the side surface 12 of the magnetic core 10, a side plate joining portion 36b, and a side plate recess 36c that is connected to the side plate fixing portion 36a and the side plate joining portion 36b and is recessed toward the inner bottom surface 12b1 of the magnetic core recess 12b.

[0113] In this configuration, the side plate recess 36c, which is part of the electrode member 30, is recessed in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b, so that the position of the magnetic core 10 can be restricted using the side plate recess 36c. This improves the vibration resistance of the inductor 100.

[0114] The inductor 100 in Example 3 is the inductor described in Example 1 or 2, and further, an insulating coat 130 is formed on the outer periphery of the bottom surface 13 of the magnetic core 10, with the bottom surface being the forming surface, and the lower surface being located at a position lower by the thickness from the forming surface. The insulating coat 130 is made of an insulating material.

[0115] This configuration allows for the provision of an insulating coat 130 with a thickness T2 on the outer periphery of the bottom surface 13 of the magnetic core 10, such that its lower surface is lower than the bottom surface 13. By filling the inside of the insulating coat 130 with a heat dissipation gel, a gap of thickness T2 can be created between the circuit board 151 and the bottom surface 13, while thermally connecting the circuit board 151 and the bottom surface 13. As a result, heat generated from the inductor 100 to the circuit board 151 can be dissipated, allowing the inductor 100 to operate properly thermally. On the other hand, when such a heat dissipation configuration is adopted, the circuit board 151 is less likely to come into contact with the bottom surface 13, thus suppressing the occurrence of short circuits between the coil element 20 of the inductor 100 and the circuit board 151. Therefore, when using the circuit board 151 to thermally optimize the operation of the inductor 100, it is possible to suppress the occurrence of short circuits and ensure that the inductor 100 operates properly.

[0116] The inductor 100 in Example 4 is an inductor described in any of Examples 1 to 3, wherein at least one of the insulating coats 130 and 140 is formed on the outer periphery, with a width from the outer periphery of the forming surface being within the range of 0.1 mm or more and a length of 1 / 4 times the width of the forming surface or less.

[0117] With this configuration, at least one of the insulating coatings 130 and 140 can be provided on the outer periphery of the forming surface (at least one of the top surface 14 and the bottom surface 13) such that the width (at least one of W1 and W2) from the outer periphery of the forming surface is within the range of 0.1 mm or more and 1 / 4 the length of the width W3 of the forming surface.

[0118] The inductor 100 in Example 5 is the inductor described in any of Examples 1 to 4, wherein the thickness of at least one of the insulating coats 130 and 140 is 0.01 mm or more and 0.2 mm or less.

[0119] With this configuration, at least one of the insulating coatings 130 and 140 can have a thickness T1 and T2 of 0.01 mm or more and 0.2 mm or less.

[0120] The inductor 100 in Example 6 is an inductor described in any of Examples 1 to 5, wherein at least one of the insulating coats 130 and 140 is continuously formed on the outer periphery of the forming surface and on a portion of the sides 11 and 12 of the magnetic core 10 that are connected to the outer periphery of the forming surface.

[0121] With this configuration, at least one of the insulating coatings 130 and 140 can be continuously formed on the outer periphery of the forming surface (at least one of the top surface 14 and the bottom surface 13) and on a portion of the side surfaces 11 and 12 of the magnetic core 10 that are connected to the outer periphery of the forming surface.

[0122] The inductor 100 in Example 7 is the inductor described in Example 6, wherein the height of the portion formed on the sides 11 and 12 of the magnetic core 10 of at least one of the insulating coats 130 and 140 is 0.1 mm or more, and the length is 1 / 4 times the height of the sides 11 and 12 or less.

[0123] With this configuration, at least one of the insulating coatings 130 and 140 can be set to a height of 0.1 mm or more and 1 / 4 the length of the height of the sides 11 and 12, as at least one of the heights H1 and H2 of the portions formed on the sides 11 and 12 of the magnetic core 10.

[0124] The electrical product 150 of Example 8 comprises a circuit board 151, an inductor 100 as described in any of Examples 1 to 7 mounted on the circuit board 151 with the bottom surface 13 of the magnetic core 10 facing it, a heat dissipation gel filled inside the insulating coat 140, and a heat dissipation housing 152 provided on the opposite side of the inductor 100 with the heat dissipation gel in between.

[0125] In this way, the inductor 100 operates properly in the electrical product 150. And, due to the properly operating inductor, the electrical product 150 also operates properly.

[0126] Furthermore, the inductor 100 of the alternative example 1 includes a magnetic core 10 having a three-dimensional shape with a side surface 12, a bottom surface 13 and a top surface 14, and containing a magnetic material; a coil element 20 having a buried portion 21 embedded in the magnetic core 10 and a coil end 22 exposed from the magnetic core 10 and extending along the side surface 12 of the magnetic core 10; and an electrode member 30 made of a metal material and joined to the coil end 22. The side surface 12 of the magnetic core 10 is provided with a magnetic core recess 12b that is recessed toward the interior of the magnetic core 10. The coil end 22 protrudes from the magnetic core recess 12b and extends along the inner bottom surface 12b1 of the magnetic core recess 12b. The electrode member 30 is a copper-based metal foil with a thickness of less than 100 μm and has a side plate 36 arranged along the side surface 12 of the magnetic core 10 and a bottom plate 34 arranged along the bottom surface 13 of the magnetic core 10. The side plate 36 has a side plate fixing portion 36a fixed to the side surface 12 of the magnetic core 10, a side plate joining portion 36b joined to the coil end 22, and a side plate recess 36c connected to the side plate fixing portion 36a and the side plate joining portion 36b and recessed in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b.

[0127] In this way, since the side plate recess 36c, which is part of the electrode member 30, is recessed in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b, the position of the magnetic core 10 can be restricted using the side plate recess 36c. This improves the vibration resistance of the inductor 100.

[0128] Furthermore, the inductor 100 in alternative example 2 is the inductor described in alternative example 1, and the side plate recess 36c may be located between the inner wall surface 12b2 of the magnetic core recess 12b and the coil end 22.

[0129] With this configuration, the position of the magnetic core 10 and the coil end 22 can be restricted using the side plate recess 36c. This improves the vibration resistance of the inductor 100.

[0130] Furthermore, the inductor 100 in alternative example 3 is the inductor described in alternative example 1 or 2, and the side plate recess 36c may be located on both sides of the coil end 22 when viewed from a direction perpendicular to the side surface 12 of the magnetic core 10.

[0131] With this configuration, the position of the magnetic core 10 can be restricted using the side plate recesses 36c located on both sides of the coil end 22. This improves the vibration resistance of the inductor 100.

[0132] Furthermore, the inductor 100 of alternative example 4 is an inductor described in any of alternative examples 1 to 3, wherein the magnetic core 10 has a first corner portion m1 located at the boundary between the side surface 12 of the magnetic core 10 and the inner wall surface 12b2 of the magnetic core recess 12b, the side plate 36 has a first bent portion n1 that abuts against the first corner portion m1 so as to cover the first corner portion m1, and the side plate recess 36c may be recessed in the direction of the inner bottom surface 12b1 starting from the first bent portion n1.

[0133] With this configuration, the position of the first corner m1 can be restricted using the first bent portion n1. This restricts the position of the magnetic core 10 and improves the vibration resistance of the inductor 100.

[0134] Furthermore, the inductor 100 in alternative example 5 is the inductor described in alternative example 4, and the first bent portion n1 may be in contact with the first corner portion m1 via an adhesive.

[0135] This configuration allows the position of the first corner m1 to be controlled via the adhesive. This controls the position of the magnetic core 10 and improves the vibration resistance of the inductor 100.

[0136] Furthermore, the inductor 100 in alternative example 6 is the inductor described in alternative example 4, wherein the magnetic core 10 has a plurality of first corners m1 in a direction along the side surface 12 of the magnetic core 10 and parallel to the bottom surface 13 of the magnetic core 10, and the side plate 36 has a plurality of first bent portions n1 corresponding to the plurality of first corners m1.

[0137] With this configuration, the positions of multiple first corners m1 can be restricted using multiple first bends n1. This restricts the position of the magnetic core 10 and improves the vibration resistance of the inductor 100.

[0138] Furthermore, the inductor 100 of alternative example 7 is an inductor described in any of alternative examples 1 to 6, wherein the coil end 22 is flat and has an outer end surface 22f1 that is in contact with the side plate joint 36b, an outer end surface 22s that is connected to the outer end surface 22f1, and a second corner portion m2 located at the boundary between the outer end surface 22f1 and the outer end surface 22s, the side plate 36 has a second bent portion n2 that abuts against the second corner portion m2 so as to cover the second corner portion m2, and the side plate recess 36c may be recessed in the direction of the inner bottom surface 12b1 starting from the second bent portion n2.

[0139] With this configuration, the position of the coil end 22 can be restricted using the second bend n2. This improves the vibration resistance of the inductor 100.

[0140] Furthermore, the inductor 100 of alternative example 8 is the inductor described in alternative example 7, wherein the coil end 22 has a plurality of second corners m2 in a direction along the side surface 12 of the magnetic core 10 and parallel to the bottom surface 13 of the magnetic core 10, and the side plate 36 has a plurality of second bends n2 corresponding to the plurality of second corners m2.

[0141] With this configuration, the positions of multiple second corners m2 can be restricted using multiple second bends n2. This restricts the position of the coil end 22 and improves the vibration resistance of the inductor 100.

[0142] Furthermore, the inductor 100 in alternative example 9 is an inductor described in any of alternative examples 1 to 8, and the depth dp2 of the side plate recess 36c may be 0.3 times or more and 0.9 times or less of the depth dp1 of the magnetic core recess 12b.

[0143] According to this, the position of the magnetic core 10 can be reliably controlled using the recess 36c of the side plate. This improves the vibration resistance of the inductor 100.

[0144] Furthermore, the inductor 100 in alternative example 10 is the inductor described in any of alternative examples 1 to 8, and the depth dp2 of the side plate recess 36c may be 1 / 2 or more of the thickness of the electrode member 30.

[0145] According to this, the position of the magnetic core 10 can be reliably controlled using the plastically deformed side plate recess 36c. This improves the vibration resistance of the inductor 100.

[0146] The inductor 100 of this disclosure may be formed by the inductor manufacturing method described below. For example, the manufacturing method of the inductor 100 includes the steps of: forming a molded body (a magnetic core with a coil embedded in it) in which the coil end 22 of the coil element 20 protrudes from the magnetic core recess 12b on the side surface 12 of the magnetic core 10 in which the winding portion of the coil element 20 is embedded and is placed in the magnetic core recess 12b; fixing the side plate 36 of the electrode member 30 to the side surface 12 of the magnetic core 10 so as to cover at least a part of the coil end 22 placed in the magnetic core recess 12b; recess forming step to form a side plate recess 36c by pushing a part of the side plate 36 of the electrode member 30 into the magnetic core recess 12b; and joining step to join the electrode member 30 to the coil end 22.

[0147] In this way, by recessing the side plate recess 36c, which is part of the electrode member 30, in the direction of the inner bottom surface 12b1 of the magnetic core recess 12b, an inductor 100 can be manufactured in which the position of the magnetic core 10 can be restricted using the side plate recess 36c. This improves the vibration resistance of the inductor 100.

[0148] Furthermore, an inductor may be realized by combining any of the inductors in Examples 1 to 7 shown above with the inductors in Other Examples 1 to 10, and the inductor obtained by this combination may be used in place of inductor 100 to realize an electrical product similar to that in Example 8.

[0149] (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.

[0150] 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.

[0151] 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]

[0152] The inductor relating to this disclosure is useful as an inductor for use in various devices and equipment. [Explanation of Symbols]

[0153] 10 magnetic core 11, 12 Side view 12a base 12b Magnetic core recess 12b1 Inner bottom surface 12b2 Interior wall surface 13. Base 14 Top surface 20 Coil Elements 21 Buried section 22 Coil ends 22f1 End outer surface 22f2 End inner surface 22s end side 30 Electrode members 34 Bottom plate 36 Side panels 36a Side plate fixing part 36b Side plate joint 36c Side plate recess 36c1 inner bottom 36c2 Inner wall 40 Joint area 80 Pressing jig 100 Inductors 130, 140 Insulating Coating 150 electrical products 151 Circuit board 152 Heat dissipation enclosure H1, H2, H3 Height m1 First corner m2 2nd corner n1 1st bending part n2 2nd bending part dp1, dp2 depth T1, T2 thickness W1, W2, W3 width

Claims

1. A magnetic core having a magnetic material, a three-dimensional shape having sides, a top surface, and a bottom surface that faces the circuit board when mounted on the circuit board, A coil element comprising a metal material, an embedded portion embedded in the magnetic core, and a coil end exposed from the magnetic core and extending along the side surface of the magnetic core, The system comprises an electrode member containing a metal material and joined to the end of the coil, The coil end extends along the side surface of the magnetic core, The electrode member is a copper-based metal foil with a thickness of less than 100 μm, and has a side plate arranged along the side surface of the magnetic core and having a side plate joint portion that is joined to the coil end, and a bottom plate arranged along the bottom surface of the magnetic core. Using the top surface of the magnetic core as the forming surface, an insulating coat is formed on the outer periphery of the forming surface, with the upper surface being located at a position higher by the thickness from the forming surface. The insulating coat is made of an insulating material. Inductor.

2. The side surface of the magnetic core is provided with a magnetic core recess that is recessed toward the interior of the magnetic core. The coil end protrudes from the magnetic core recess and extends along the inner bottom surface of the magnetic core recess. The side plate has a side plate fixing portion fixed to the side surface of the magnetic core, a side plate joining portion, and a side plate recess connected to the side plate fixing portion and the side plate joining portion and recessed in the direction of the inner bottom surface of the magnetic core recess. The inductor according to claim 1.

3. Furthermore, using the bottom surface of the magnetic core as the forming surface, an insulating coat is formed on the outer periphery of the forming surface, having a lower surface at a position lower by the thickness of the forming surface. This insulating coat is made of an insulating material. The inductor according to claim 1.

4. The insulating coating is formed on the outer periphery of the formed surface, with a width of 0.1 mm or more and a length of 1 / 4 times the width of the formed surface or less. An inductor according to any one of claims 1 to 3.

5. The thickness of the insulating coating is 0.01 mm or more and 0.2 mm or less. An inductor according to any one of claims 1 to 3.

6. The insulating coating is continuously formed on the outer periphery of the forming surface and on a portion of the side surface of the magnetic core that is connected to the outer periphery of the forming surface. An inductor according to any one of claims 1 to 3.

7. The height of the portion of the insulating coating formed on the side surface of the magnetic core is 0.1 mm or more, and no more than 1 / 4 the length of the height of the side surface. The inductor according to claim 6.

8. Circuit board and The inductor according to claim 1 is mounted on the circuit board such that the bottom surface of the magnetic core faces the other side, The heat dissipation gel filled inside the insulating coating, The system comprises a heat dissipation housing provided on the opposite side of the inductor, with the heat dissipation gel in between. Electrical appliances.

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