Inductor and method of manufacturing an inductor

Abstract

The present application relates to an inductor and a manufacturing method of an inductor. In an inductor having a metal plate embedded in a magnetic core, under the limitation of component size, smaller DC resistance, larger inductance, and DC superimposed current are achieved. The inductor is provided with a magnetic core containing magnetic powder and a conductor embedded in the magnetic core. The magnetic core is provided with a mounting surface facing the mounting substrate side during mounting, a pair of end surfaces orthogonal to the mounting surface, and a pair of side surfaces orthogonal to the mounting surface and the pair of end surfaces. The conductor is plate-shaped and is provided with a wire portion extending inside the magnetic core over the pair of end surfaces, and a pair of electrode portions provided at end portions on both sides of the wire portion and extending from the end surfaces of the magnetic core over the mounting surface. The wire portion includes a flat plate portion in a strip shape. One surface of the electrode portion facing the magnetic core is embedded in the magnetic core, and the other surface of the electrode portion opposite to the one surface is exposed from the magnetic core.

Description

Technical Field

[0001] This invention relates to inductors and methods for manufacturing inductors. Background Technology

[0002] In existing electronic components where external terminals are formed by bending wires that are led out from a metal plate embedded in a magnetic core, the wire portion is plated to improve solder wettability.

[0003] Patent Document 1 describes an inductor consisting of a metal plate and a molded body containing a portion of an inner metal plate. The metal plate includes a first metal plate portion embedded in the molded body and a second metal plate portion extending outward from the first metal plate portion into the molded body. The second metal plate portion is bent along the side of the molded body and the substrate mounting surface to form an external terminal.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2019-153642

[0005] However, in the prior art described above, after the metal plate is embedded in the molded body, a portion of the metal plate leading out of the molded body, i.e. the wire, is bent to the substrate mounting surface of the molded body to form an external terminal. Therefore, the molded body needs to be formed with a thickness of at least the wire that is thinner than the component height of the inductor, and the achievable inductance and DC superposition current can be limited to a small value.

[0006] Furthermore, the force applied to the conductor during bending increases depending on its width, potentially causing mechanical damage such as cracks or defects in the molded body. Therefore, from the viewpoint of avoiding mechanical damage in the molded body, the practically usable conductor width is limited, which can become a limiting factor in reducing the DC resistance of the inductor. Summary of the Invention

[0007] The purpose of this invention is to achieve a smaller DC resistance value and a larger inductance and DC superposition current structure in an inductor consisting of a metal plate embedded in a magnetic core, while being limited by the required component size.

[0008] One aspect of the present invention is an inductor comprising a magnetic core containing magnetic powder and a conductor embedded in the magnetic core. The magnetic core includes: a mounting surface facing a mounting substrate during mounting; a pair of end faces orthogonal to the mounting surface; and a pair of side faces orthogonal to the mounting surface and the pair of end faces. The conductor is plate-shaped and includes: a conductive portion extending throughout the pair of end faces inside the magnetic core; and a pair of electrode portions disposed at the ends of the conductive portions on both sides and extending from the end faces of the magnetic core throughout the mounting surface. The conductive portion includes a strip-shaped plate portion. One side of the electrode portion facing the magnetic core is embedded in the magnetic core, and the other side of the electrode portion facing the one side is exposed from the magnetic core.

[0009] Another aspect of the present invention is a method for manufacturing an inductor comprising a magnetic core containing magnetic powder and a conductor embedded in the magnetic core. The manufacturing method includes: a step of forming the conductor by bending a conductive plate; and a step of embedding the conductor in the magnetic core after the step of forming the conductor, such that a portion of the conductor protrudes from the magnetic core. The magnetic core includes: a mounting surface facing a mounting substrate side during mounting, a pair of end faces orthogonal to the mounting surface, and a pair of side faces orthogonal to the mounting surface and the pair of end faces. The conductor is plate-shaped and includes: a conductive portion extending throughout the pair of end faces inside the magnetic core when embedded in the magnetic core; and a pair of electrode portions disposed at the ends of the conductive portion on both sides and extending from the end faces of the magnetic core throughout the mounting surface. The conductive portion includes a strip-shaped flat plate portion. When embedded in the magnetic core, one side of the electrode portion facing the magnetic core is embedded in the magnetic core, and the other side of the electrode portion facing the one side protrudes from the magnetic core.

[0010] According to the present invention, it is possible to reduce the DC resistance value in an inductor made of a metal plate embedded in a magnetic core, while limiting the required component size, and to achieve a structure with larger inductance and DC superimposed current. Attached Figure Description

[0011] Figure 1 This is a perspective view of the inductor involved in the embodiment of the present invention, viewed from the top surface side.

[0012] Figure 2 This is a top view of the side of the inductor.

[0013] Figure 3 This is a top view of the inductor's end face.

[0014] Figure 4 This is a top view of the mounting surface of the inductor.

[0015] Figure 5It is a perspective three-dimensional diagram showing the internal structure of an inductor.

[0016] Figure 6 This is a schematic diagram of the manufacturing process of inductor 1.

[0017] Figure 7 This is a top view of the inductor's end face.

[0018] Figure 8 yes Figure 7 The inductor shown is viewed along section VIII-VIII.

[0019] Figure 9 It means Figure 5 A diagram showing the structure of the conductor.

[0020] Figure 10 This is a diagram showing the structure of the conductor involved in the first variation.

[0021] Figure 11 Is using Figure 10 A perspective view of an inductor for the conductor shown.

[0022] Figure 12 This is a diagram showing the structure of the conductor involved in the second variation.

[0023] Figure 13 Is using Figure 12 A perspective view of an inductor for the conductor shown.

[0024] Figure 14 This is a diagram showing the structure of the conductor involved in the third variation.

[0025] Figure 15 Is using Figure 14 A perspective view of an inductor for the conductor shown.

[0026] Figure 16 This is a diagram showing the structure of the conductor involved in the fourth variation.

[0027] Explanation of reference numerals in the attached figures

[0028] 1, 80…Inductor; 2…Blank; 4…External electrode; 10…Mounting surface; 12…Upper surface; 14…End face; 16, 85…Side surface; 20, 20-1, 20-2, 20-3, 20-4…Conductor; 22, 22-1, 22-2, 22-3, 22-4…Wire section; 24…Electrode section; 24A…Surface; 26…First electrode section; 27…Second electrode section; 30…Magnetic core; 40…First plate; 42…Second plate; 50…Nickel plating (Ni plating); 51…Tin plating (Sn plating); 60, 60-1, 60-2, 60-3, 60-4…Plate section; 61, 62, 63, 64, 65, 66, 67…Strip section. Detailed Implementation

[0029] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0030] Figure 1 This is a perspective view of the inductor 1 according to this embodiment, viewed from the top surface 12. Figure 2 This is a top view of the side 16 of inductor 1. Figure 3 This is a top view of the end face 14 of inductor 1. Figure 4 This is a top view of the mounting surface 10 of inductor 1.

[0031] The inductor 1 in this embodiment is configured as a surface-mount electronic component, having a generally rectangular blank 2 and a pair of external electrodes 4 disposed on the surface of the blank 2.

[0032] Hereinafter, in blank 2, the surface facing the mounting substrate (not shown) during installation will be defined as mounting surface 10. Figure 4 The surface opposite the mounting surface 10 is called the upper surface 12, the opposite surface orthogonal to the mounting surface 10 is called the end surface 14, and the opposite surface orthogonal to these mounting surfaces 10 and the pair of end surfaces 14 is called the side surface 16.

[0033] In addition, such as Figure 1 As shown, the distance from the mounting surface 10 to the upper surface 12 is defined as the thickness T of the blank 2, the distance between a pair of side surfaces 16 is defined as the width W of the blank 2, and the distance between a pair of end faces 14 is defined as the length L of the blank 2.

[0034] Figure 5 This is a perspective perspective view showing the internal structure of inductor 1.

[0035] The blank 2 has a conductor 20 and a generally rectangular magnetic core 30 in which the conductor 20 is embedded, and is configured as a conductor-encased magnetic component in which the conductor 20 is encased in the magnetic core 30.

[0036] The magnetic core 30 is a molded body that is approximately rectangular in shape by compressing and heating a mixture of magnetic powder and resin while the conductor 20 is encased inside. The surface of the magnetic core 30 has a more oxidized insulating film than the interior of the magnetic core 30. Furthermore, in this embodiment, in addition to the magnetic powder and resin, barium sulfate is also mixed in the mixture as a lubricant.

[0037] In the mixed powder of this embodiment, the amount of resin relative to the magnetic powder is approximately 3.1 wt%.

[0038] In addition, the magnetic powder of this embodiment contains two types of particles: large magnetic particles with a relatively large average particle size and small magnetic particles with a relatively small average particle size. During compression molding, the small magnetic particles enter the spaces between the large magnetic particles together with the resin, thereby increasing the filling rate of the magnetic core 30 and also improving the magnetic permeability.

[0039] Here, the ratio (weight ratio) of the first magnetic particle to the second magnetic particle is 70:30 to 85:15, preferably 70:30 to 80:20, and in this embodiment it is 75:25.

[0040] In addition, it is preferable that the ratio of the average particle size of the first magnetic particle to that of the second magnetic particle is 5.0 or higher.

[0041] In addition, magnetic powder may also contain particles with an average particle size between the first magnetic particle and the second magnetic particle, thus containing particles of three or more particle sizes.

[0042] In this embodiment, both the first and second magnetic particles are particles having a metal particle and an insulating film covering their surface. The metal particle is made of Fe-Si based amorphous alloy powder, and the insulating film is made of zinc phosphate. The metal particle is covered by the insulating film, thereby improving the insulation resistance and withstand voltage.

[0043] In addition, the metal particles in the first magnetic particle can also be Cr-free Fe-C-Si alloy powder, Fe-Ni-Al alloy powder, Fe-Cr-Al alloy powder, Fe-Si-Al alloy powder, Fe-Ni alloy powder, or Fe-Ni-Mo alloy powder.

[0044] In addition, other phosphates (magnesium phosphate, calcium phosphate, manganese phosphate, cadmium phosphate, etc.) or resin materials (organosilicon resins, epoxy resins, phenolic resins, polyamide resins, polyimide resins, polyphenylene sulfide resins, etc.) can also be used for the insulating film in the first and second magnetic particles.

[0045] In the mixed powder of this embodiment, the resin material used is an epoxy resin with bisphenol A type epoxy resin as the main agent.

[0046] In addition, epoxy resin can also be phenolic varnish type epoxy resin.

[0047] In addition, the resin material can be other than epoxy resin, and it can be two or more types of materials. For example, in addition to epoxy resin, thermosetting resins such as phenolic resin, polyester resin, polyimide resin, and polyolefin resin can also be used.

[0048] like Figure 5 As shown, the conductor 20 includes: a wire portion 22 extending through a pair of end faces 14 throughout the interior of the magnetic core 30, and an electrode portion 24 integrally formed at both ends of the wire portion 22.

[0049] The electrode portion 24 has its surface 24A exposed from the end face 14 of the magnetic core 30 and the mounting surface 10, respectively. To ensure mountability, the external electrode 4 is formed by sequentially plating nickel (Ni) and tin (Sn) on these surfaces 24A. Furthermore, the external electrode 4 formed on the mounting surface 10 is electrically connected to the wiring of the circuit board by appropriate mounting means such as solder.

[0050] In this embodiment, such as Figures 1-5 As shown, the electrode portion 24 of the conductor 20 is configured such that only surface 24A is exposed on the mounting surface 10 and end face 14, thus suppressing the amount of protrusion from the magnetic core 30. Therefore, since the protrusion of the electrode portion 24 is almost negligible, the magnetic core 30 can be increased to the same size as the specified dimensions of the inductor 1, enabling a small, low-profile, but high-performance inductor 1.

[0051] If the length of the conductor portion 22 in the direction of the width W of the magnetic core 30 is defined as the conductor portion width WA, and the length of the electrode portion 24 is defined as the electrode width WB, then as Figure 5 As shown, in this embodiment, the electrode width WB of the electrode portion 24 is wider than the wire portion width WA, thereby achieving low DC resistance.

[0052] The electrode portion 24 described above has an L-shaped LT cross-section in the LT plane in each direction containing the length L and thickness T of the magnetic core 30.

[0053] In detail, the electrode portion 24 has a first electrode portion 26 that extends by bending approximately vertically at the end 22A of the conductor portion 22, and a second electrode portion 27 that extends approximately vertically at the lower end 26A of the first electrode portion 26, the first electrode portion 26 and the second electrode portion 27 forming an L-shape. Moreover, the surfaces 24A of the first electrode portion 26 and the second electrode portion 27 are exposed from the end face 14 and the mounting surface 10 of the magnetic core 30, forming the external electrode 4.

[0054] According to the electrode portion 24 described above, compared to the case where the conductor portion 22 and the electrode portion 24 (external electrode 4) are separately constructed, there is no joint surface between the conductor portion 22 and the electrode portion 24 (external electrode 4) in the low resistance region where the current mainly flows in the external electrode 4, that is, between the conductor portion 22 and the electrode portion 24 (external electrode 4). Therefore, the resistance value can be suppressed and a larger current can flow.

[0055] Furthermore, the conductor 20 in this embodiment is formed of tough copper, which allows a larger current to flow through it.

[0056] Based on the structure described above, the inductor 1 of this embodiment can achieve an inductance of about 10nH or more, a DC resistance of about 0.85mΩ or less, a rated current of 15A or more when the temperature rises (wherein, at a temperature rise of 40 degrees), and a DC superimposed current of 15A or more (wherein, at a frequency of 1MHz) with dimensions of about 2.5mm in length L, about 2.0mm in width W, and about 1.0mm in thickness T.

[0057] The aforementioned inductor 1 is used as an impedance matching coil (matching coil) in power supply circuits and high-frequency circuits of DC-DC converters with charge pump mode that boosts voltage through capacitors and switches, and is used in electronic devices such as personal computers, DVD players, digital cameras, TVs, mobile phones, smartphones, automotive electronics, and medical / industrial machinery. However, the application of inductor 1 is not limited to this; for example, it can also be used in tuning circuits, filtering circuits, and rectifier smoothing circuits.

[0058] Furthermore, in inductor 1, a preform protective layer may be formed on the entire surface of the preform 2, excluding the area of ​​the external electrode 4. The material for the preform protective layer can be, for example, a thermosetting resin such as epoxy resin, polyimide resin, or phenolic resin, or a thermoplastic resin such as polyethylene resin or polyamide resin. In addition, these resins may also include fillers containing silica, titanium dioxide, etc.

[0059] Figure 6 This is a schematic diagram of the manufacturing process of inductor 1.

[0060] As shown in the figure, the manufacturing process of inductor 1 includes: conductor component forming process, blank tablet forming process, first tablet insertion process, second tablet configuration process, thermoforming / curing process, tumbling process, pretreatment process, and plating process.

[0061] The conductor component forming process is the process of forming the aforementioned conductor 20.

[0062] In this embodiment, firstly, a copper sheet of a predetermined shape is formed by punching a copper plate of a predetermined thickness. Next, the conductor 20 is formed by bending the copper sheet. At this time, the first electrode portion 26 and the second electrode portion 27 of the electrode portion 24 are also bent. That is, through this conductor component forming process, a conductor 20 is formed that integrally has the aforementioned wire portion 22 and electrode portion 24, and the first electrode portion 26 and the second electrode portion 27 of the electrode portion 24 are pre-formed (i.e., pre-fabricated) before being embedded in the magnetic core 30.

[0063] The flat plate forming process is a process of forming the two preforms, the first flat plate 40 and the second flat plate 42.

[0064] The preform is formed into an easily manipulated solid by pressing the above-mentioned mixed powder, which serves as the blank 2, into a preform. The first plate 40 and the second plate 42 are preforms disposed on the lower and upper sides of the conductor portion 22 of the conductor 20, respectively, and are both formed into a generally plate shape.

[0065] The first plate insertion process is a process in which, after the conductor 20 is placed in the forming metal mold, the first plate 40 is inserted under the wire portion 22 of the conductor 20 and between a pair of electrode portions 24. More specifically, for the conductor 20, by providing L-shaped electrode portions 24 in the LT cross-section at the ends 22A on both sides of the wire portion 22, the shape of its LT cross-section is formed into a roughly C-shape, and the first plate 40 is inserted in the space surrounded by these wire portions 22 and the pair of electrode portions 24.

[0066] The second plate arrangement process is the process of placing the second plate 42 on the wire portion 22 of the conductor 20.

[0067] In the thermoforming / curing process, the first plate 40 and the second plate 42, which are disposed in the forming metal mold, are heated while pressure is applied in the overlapping direction of the first plate 40 and the second plate 42 to cure them, thereby integrating the first plate 40, the conductor 20, and the second plate 42. Thus, a molded body containing the conductor 20 is formed.

[0068] As described above, since the first plate 40 is housed within the space surrounded by the conductor portion 22 and the pair of electrode portions 24, a molded body is obtained in which the conductor portion 22 is embedded in the molded body, and the surface of the electrode portion 24, which is composed of the first electrode portion 26 and the second electrode portion 27, is exposed substantially coplanar with the magnetic core 30. Furthermore, since the first electrode portion 26 and the second electrode portion 27 of the electrode portion 24 are formed in the aforementioned conductor component molding process, it is not necessary to perform processing on the molded body after molding to form these first electrode portions 26 and second electrode portions 27.

[0069] The tumbling process is a process of tumbling the molded body, through which the corners of the molded body are rounded.

[0070] The pretreatment process involves heat treatment and cleaning as a surface treatment for the molded body to be used in the subsequent plating process. In the plating process, nickel (Ni) and tin (Sn) are sequentially plated onto the surface 24A of the electrode portion 24 by tubular plating.

[0071] like Figure 5 As shown, the inductor 1 of this embodiment, manufactured as described above, comprises a generally rectangular magnetic core 30 containing magnetic powder and a conductor 20 embedded within the magnetic core 30. The conductor 20 includes a conductive portion 22 enclosed within the magnetic core 30 and first electrode portions 26 extending from both ends of the conductive portion 22 in the thickness direction of the conductive portion 22. Furthermore, each end of the first electrode portion 26 opposite to the conductive portion 22 has a second electrode portion 27 extending in the thickness direction of the first electrode portion 26. Moreover, the conductive portion 22 includes a strip-shaped flat plate portion viewed from the top surface 12 side. Additionally, one side of the first electrode portion 26 and the second electrode portion 27 facing the magnetic core 30 is embedded within the magnetic core 30, while the other side of the first electrode portion 26 and the second electrode portion 27 facing the aforementioned one side, i.e., surface 24A, is exposed from the magnetic core 30. Hereinafter, "top view" refers to the view from the top surface 12 side.

[0072] Figure 8 yes Figure 7 The diagram shows a section view of inductor 1 along section VIII-VIII. Here, Figure 7 and Figure 3 Similarly, this is a top view of the end face 14 of inductor 1. Additionally, Figure 9 This is a diagram showing the structure of conductor 20, and is a top view of conductor 20 as viewed from the upper surface 12 side of inductor 1.

[0073] like Figure 8 As shown, the conductor 20 has: a wire portion 22 enclosed within the magnetic core 30; a first electrode portion 26 extending downwards from both ends of the wire portion 22; and a second electrode portion 27 extending left-right from the end of the first electrode portion 26. Furthermore, as... Figure 9 As shown, the conductor section 22 includes a strip-shaped flat plate section 60 (shaded area in the figure) viewed from above.

[0074] In addition, such as Figure 8 As shown, one side of the first electrode portion 26 and the second electrode portion 27 facing the magnetic core 30 (the side opposite to surface 24A) is embedded in the magnetic core 30. Moreover, the surface 24A of the first electrode portion 26 and the second electrode portion 27 is exposed from the magnetic core 30, and a nickel plating layer 50 and a tin plating layer 51 are formed thereon.

[0075] In the inductor 1 having the above-described structure, the conductor 20, formed by bending the conductive plate, is embedded in the magnetic core 30, and the portion of the second electrode portion 27 constituting the conductor 20 that faces the magnetic core 30 and is opposite to the surface 24A exposed from the magnetic core 30 is embedded (or buried) in the magnetic core 30.

[0076] This inductor 1 structure is achieved by embedding a pre-bent conductor 20 into the magnetic core 30, which is not possible by bending the conductor 20 after embedding it into the magnetic core 30, as was done previously. That is, mechanical damage to the magnetic core 30 caused by bending the conductor 20 after embedding it into the magnetic core 30 cannot occur in the inductor 1. Furthermore, in the inductor 1, the electrode width WB of the first electrode portion 26 and the second electrode portion 27 can be pre-ensured with a wider upper limit than the required width W of the inductor 1 as specified in the inductor 1 specifications, thus reducing the DC resistance compared to the past.

[0077] Furthermore, in inductor 1, such as Figure 8 As shown, the surface of the second electrode portion 27 opposite to the surface 24A is embedded within the magnetic core 30. Therefore, the mounting surface 10 and the surface 24A of the second electrode portion 27 can be formed almost coplanarly, and the thickness of the magnetic core 30 can be made to be almost the same as the thickness T of the inductor 1 as specified in the requirements of the inductor 1. That is, unlike conventional inductors, in the inductor 1, it is not necessary to reduce the thickness of the second electrode portion 27 relative to the thickness of the inductor 1 to form the thickness of the magnetic core 30 as a molded body. Therefore, in the inductor 1, compared with conventional inductors, the volume of the magnetic particles surrounding the conductor portion 22 can be increased, thus enabling a larger inductance and a larger DC superposition current.

[0078] Based on the above, in inductor 1, under the constraint of the required component size, the DC resistance value can be suppressed to be smaller, and a larger inductance and DC superposition current can be achieved.

[0079] In this embodiment, when viewed from above, the flat plate portion 60 constituting the conductor portion 22 extends in a direction orthogonal to the width direction of the first electrode portion 26 (i.e., the L direction). However, the structure of the flat plate portion constituting the conductor portion 22 is not limited to this. The flat plate portion can be configured in any shape to achieve a desired length corresponding to the inductance specified from the requirements of the inductor 1. As an example, the flat plate portion can be configured in any of the following shapes.

[0080] (a) The plate portion may be configured to include a strip-shaped portion that extends at a predetermined angle relative to the width direction (W direction) of the first electrode portion 26 when viewed from above.

[0081] (b) The flat plate portion may be configured to include a strip-shaped portion extending in the width direction (W direction) of the first electrode portion 26 when viewed from above, and a strip-shaped portion extending in a direction orthogonal to the width direction (L direction) of the first electrode portion 26.

[0082] (c) The flat plate portion may be configured to include a curved strip portion when viewed from above.

[0083] The following describes a variation of the conductor 20 used in inductor 1.

[0084] [First Variation]

[0085] Figure 10 This diagram shows the structure of conductor 20-1 in the first modified example of conductor 20, and is a top view of conductor 20-1 viewed from the upper surface 12 side of inductor 1. Additionally, Figure 11 This is a perspective perspective view showing the internal structure of inductor 1 when conductor 20-1 is used. Furthermore, in Figure 10 and Figure 11 In China, for the sake of Figure 9 and Figure 5 The constituent elements shown are the same as those used in the diagram. Figure 9 and Figure 5 The same reference numerals are used in the accompanying drawings to indicate the same figures as those mentioned above. Figure 9 and Figure 5 Explanation.

[0086] The conductor 20-1 involved in this modification includes a wire portion 22-1 having a flat plate portion 60-1 with the structure described in (a) above, instead of a wire portion 22 having a flat plate portion 60. Specifically, as an example of the structure described in (a) above, the flat plate portion 60-1 is configured as a straight strip-shaped portion extending at a predetermined angle θ relative to the width direction (W direction) of the first electrode portion 26 when viewed from above, forming a shape that is rotationally symmetrical about a center point A. The center point A is, for example, the intersection of the diagonals of the generally rectangular upper surface 12 of the inductor 1.

[0087] When viewed from above, the plate portion 60-1 of this modified example extends at a predetermined angle θ relative to the width direction of the first electrode portion 26. Therefore, the length measured along the extension direction of the plate portion 60-1 when viewed from above is longer than the length of the plate portion 60. Thus, by using the conductor 20-1, the inductance of the inductor 1 can be increased compared to the case where the conductor 20 is used.

[0088] [Second variation]

[0089] Figure 12This diagram shows the structure of conductor 20-2 in the second modified example of conductor 20, and is a top view of conductor 20-2 viewed from the upper surface 12 side of inductor 1. Additionally, Figure 13 This is a perspective perspective view showing the internal structure of inductor 1 when conductor 20-2 is used. Furthermore, in Figure 12 and Figure 13 In China, for the sake of Figure 9 and Figure 5 The constituent elements shown are the same as those used in the diagram. Figure 9 and Figure 5 The same reference numerals are used in the accompanying drawings to indicate the same figures as those mentioned above. Figure 9 and Figure 5 Explanation.

[0090] The conductor 20-2 in this modified example has a wire portion 22-2 that includes a flat plate portion 60-2 having the structure described above (b), instead of a wire portion 22 having a flat plate portion 60. Specifically, the flat plate portion 60-2 includes a strip-shaped portion 61 extending in the width direction of the first electrode portion 26, and two strip-shaped portions 62 extending in a direction orthogonal to the width direction of the first electrode portion 26, and is configured to be bent into a crank-like shape when viewed from above.

[0091] In this modified example, the flat plate portion 60-2 is configured to include a shape that is bent in a crank-like manner when viewed from above. Therefore, the length of the flat plate portion 60-2, measured along its extension direction when viewed from above, is longer than the lengths of the flat plate portions 60 and 60-1. Therefore, by using the conductor 20-2, the inductance of the inductor 1 can be further increased compared to the case where the conductors 20 and 20-1 are used.

[0092] [Third variation]

[0093] Figure 14 This diagram shows the structure of conductor 20-3, which is a third variation of conductor 20, and is a top view of conductor 20-3 as viewed from the upper surface 12 side of inductor 1. Additionally, Figure 15 This is a perspective perspective view showing the internal structure of inductor 1 when conductor 20-3 is used. Furthermore, in Figure 14 and Figure 15 In China, for the sake of Figure 9 and Figure 5 The constituent elements shown are the same as those used in the diagram. Figure 9 and Figure 5 The same reference numerals are used in the accompanying drawings to indicate the same figures as those mentioned above. Figure 9 and Figure 5 Explanation.

[0094] The conductor 20-3 in this modified example has a wire portion 22-3 that includes a flat plate portion 60-3 having the structure described above (b), instead of a wire portion 22 having a flat plate portion 60. Specifically, the flat plate portion 60-3 includes two strip-shaped portions 63 and 64 extending in the width direction of the first electrode portion 26, and three strip-shaped portions 65, 66, and 67 extending in a direction orthogonal to the width direction of the first electrode portion 26, and is configured to include a shape that is bent into an approximate U-shape when viewed from above.

[0095] In this modified example, the flat plate portion 60-3 is configured to include a shape that bends into a U-shape when viewed from above. Therefore, the length of the flat plate portion 60-3, measured along its extension direction when viewed from above, is longer than the lengths of the flat plate portions 60, 60-1, and 60-2. Therefore, by using conductor 20-3, the inductance of the inductor 1 can be further increased compared to the case where conductors 20, 20-1, and 20-2 are used.

[0096] [Fourth variation]

[0097] Figure 16 This diagram shows the structure of conductor 20-4, which is a fourth variation of conductor 20, and is a top view of conductor 20-4 viewed from the upper surface 12 side of inductor 1. Furthermore, in Figure 16 In China, for the sake of Figure 9 The constituent elements shown are the same as those used in the diagram. Figure 9 The same reference numerals are used in the accompanying drawings to indicate the same figures as those mentioned above. Figure 9 Explanation.

[0098] In this modified example, the conductor 20-4 includes a wire portion 22-4 having a flat plate portion 60-4 with the structure described above (c), instead of the wire portion 22 having the flat plate portion 60. Specifically, the flat plate portion 60-4 includes a curved strip portion and is configured in a generally S-shape.

[0099] In this modified example, the flat plate portion 60-4 is configured to include a curved strip-shaped portion when viewed from above. Therefore, the length measured along the extending direction of the flat plate portion 60-4 is longer than the length of the flat plate portion 60. Therefore, by using the conductor 20-4, the inductance of the inductor 1 can be increased compared to the case where the conductor 20 is used.

[0100] As described above, the inductor 1 according to the above embodiment includes: a magnetic core 30 containing magnetic powder, and a conductor 20 embedded in the magnetic core 30. The magnetic core 30 includes: a mounting surface 10 facing the mounting substrate side during mounting, a pair of end faces 14 orthogonal to the mounting surface 10, and a pair of side faces 16 orthogonal to the mounting surface 10 and the pair of end faces 14. In addition, the conductor 20 is plate-shaped and includes: a wire portion 22 extending throughout the pair of end faces 14 inside the magnetic core 30; and a pair of electrode portions, provided at the ends 22A on both sides of the wire portion 22, and extending from the end faces of the magnetic core throughout the mounting surface. In addition, the wire portion 22 includes a strip-shaped plate portion 60. Moreover, one side of the electrode portion 24 facing the magnetic core 30 is embedded in the magnetic core 30, and the other side of the electrode portion 24 facing the aforementioned one side, i.e., surface 24A, is exposed from the magnetic core 30.

[0101] According to this structure, in the inductor 1, which is composed of a metal plate, i.e. a conductor 20, embedded in the magnetic core 30, the DC resistance value can be reduced to a smaller value under the constraint of the required component size, and a larger inductance and DC superposition current can be achieved.

[0102] Furthermore, the flat plate portion 60 of the conductor portion 22 extends in a direction orthogonal to the end face 14 of the magnetic core 30. Based on this structure, the conductor 20 can be formed in a simple shape.

[0103] Furthermore, in the modified example of conductor 20, the flat plate portion 60-1 of the conductor 20-1 extends obliquely relative to a direction orthogonal to the end face 14 of the magnetic core 30. Additionally, in the modified examples of conductor 20-2 and 20-3, the flat plate portions 60-2 and 60-3 of the conductor portions 22-2 and 22-3 include: a strip-shaped portion 61 extending in a direction orthogonal to the side surface 16 of the magnetic core 30, and a strip-shaped portion 62 extending in a direction orthogonal to the end face 14 of the magnetic core 30. As an example, the flat plate portion 60-2 is formed into a crank-like shape. As another example, the flat plate portion 60-3 is formed into a shape approximately U-shaped. Furthermore, in the modified example of conductor 20-4, the flat plate portion 60-4 of the conductor portion 22-4 includes a curved strip-shaped portion 63. As an example, the flat plate portion 60-4 is formed into an S-shaped shape.

[0104] Based on these structures, compared to the case where the plate portion extends only in a direction orthogonal to the end face 14 of the magnetic core 30, the length of the plate portion, measured in the extension direction of the plate portion, can be increased, thereby increasing the inductance of the inductor 1.

[0105] Furthermore, the manufacturing method involved in this embodiment is a method for manufacturing an inductor 1 comprising a magnetic core 30 containing magnetic powder and a conductor 20 embedded in the magnetic core 30. This manufacturing method includes: a step of forming the conductor 20 by bending a conductive plate; and a step of embedding the conductor 20 within the magnetic core 30 after the forming step, such that a portion of the conductor 20 is exposed from the magnetic core 30. The magnetic core 30 includes: a mounting surface 10 facing the mounting substrate side during mounting, a pair of end faces 14 orthogonal to the mounting surface 10, and a pair of side faces 16 orthogonal to the mounting surface 10 and the pair of end faces 14. The conductor 20 is plate-shaped and includes: a conductive portion 22 extending throughout the pair of end faces 14 inside the magnetic core 30 when embedded in the magnetic core 30; and a pair of electrode portions 24 disposed at the ends of the conductive portion 22 on both sides and extending from the end faces 14 of the magnetic core 30 throughout the mounting surface 10. Moreover, the conductive portion includes a strip-shaped flat plate portion 60. In addition, when embedded in the magnetic core 30, one side of the electrode portion 24 facing the magnetic core 30 is embedded in the magnetic core 30, and the other side of the electrode portion 24 facing that side, i.e., surface 24A, is exposed from the magnetic core 30.

[0106] According to this structure, it is possible to manufacture an inductor 1 that includes a plate-shaped conductor 20 embedded in a magnetic core 30, which can suppress the DC resistance value to a smaller value and achieve a larger inductance and DC superimposed current under the constraints of the required component size.

[0107] Furthermore, the above-described embodiments are merely illustrative examples of one aspect of the present invention, and can be arbitrarily modified and applied without departing from the spirit of the present invention.

[0108] In addition, unless otherwise specified, the horizontal and vertical directions, various values, shapes, and materials in the above embodiments include the range that have the same effect as these directions, values, shapes, and materials (the so-called equivalent range).

Claims

1. An inductor comprising a magnetic core containing magnetic powder and a conductor embedded in the magnetic core, The above-mentioned magnetic core has the following features: The mounting surface facing the mounting substrate during installation; A pair of end faces orthogonal to the aforementioned mounting surface; and A pair of side surfaces orthogonal to the aforementioned mounting surface and the aforementioned pair of end faces. The aforementioned conductor is plate-shaped and possesses: The conductive portion extends throughout the pair of end faces inside the aforementioned magnetic core; and A pair of electrode portions are disposed at the ends of the aforementioned conductor portion on both sides, and extend from the aforementioned end face of the magnetic core across the aforementioned mounting surface, and the pair of electrode portions extend to each of the aforementioned side faces. The aforementioned conductor section includes a strip-shaped flat plate section. One side of the electrode portion facing the magnetic core is embedded within the magnetic core, while the other side of the electrode portion, facing the aforementioned one side, protrudes from the magnetic core. The strip-shaped plate portion is connected to the electrode portion via the end at a position inside the magnetic core further inward than the two ends of the electrode portion facing the side, and the two ends of the electrode portion are closer to the side than any part of the wire portion.

2. The inductor according to claim 1, wherein, The flat plate portion of the aforementioned conductor extends in a direction orthogonal to the aforementioned end face.

3. The inductor according to claim 1, wherein, The aforementioned flat plate extends at an angle relative to a direction orthogonal to the aforementioned end face.

4. The inductor according to claim 1, wherein, The aforementioned flat plate portion includes: a strip-shaped portion extending in a direction orthogonal to the aforementioned side surface, and a strip-shaped portion extending in a direction orthogonal to the aforementioned end face.

5. The inductor according to claim 1, wherein, The aforementioned flat plate portion includes a curved strip-shaped portion.

6. A method for manufacturing an inductor, the inductor comprising a magnetic core containing magnetic powder and a conductor embedded in the magnetic core, the method comprising: The process of forming the above-mentioned conductor by bending the conductive plate; and Following the process of forming the conductor, the process of embedding the conductor within the magnetic core so that a portion of the conductor protrudes from the magnetic core. The aforementioned magnetic core includes: a mounting surface facing the mounting substrate during installation, a pair of end faces orthogonal to the mounting surface, and a pair of side faces orthogonal to the mounting surface and the pair of end faces. The conductor is plate-shaped and includes: a conductive portion that extends throughout the pair of end faces of the magnetic core when embedded therein; and a pair of electrode portions disposed at the ends of the conductive portion on both sides, extending from the end faces of the magnetic core throughout the mounting surface, and the pair of electrode portions extending to each of the aforementioned side faces. The aforementioned conductor section includes a strip-shaped flat plate section. With the electrode portion embedded in the magnetic core, one side of the electrode portion facing the magnetic core is embedded within the magnetic core, while the other side of the electrode portion facing the magnetic core is exposed. The strip-shaped plate portion is connected to the electrode portion via the end at a position inside the magnetic core further inward than the two ends of the electrode portion facing the side, and the two ends of the electrode portion are closer to the side than any part of the wire portion.

Images