Inductor and method for manufacturing the same

Abstract

An inductor (100) comprises: an exterior member (10) having a bottom surface (11) and lateral surfaces (12a); and an energizing member (20) partially covered by the exterior member (10). The energizing member (20) has: a coil part (21) covered by the exterior member (10); leading-out parts (22) extending toward the bottom surface (11) in a state of being connected to both ends of the coil part (21) and being covered by the exterior member (10); and terminal electrode parts (23) connected to the leading-out parts (22) and exposed from the bottom surface (11) of the exterior member (10). The lateral surfaces (12a) are provided with recesses (15) that are dented toward inside of the exterior member (10) from the lateral surfaces (12a) and that are contiguous to the bottom surface (11). The terminal electrode parts (23) extend toward the recesses (15) along the bottom surface (11) and is bent from the bottom surface (11) toward the recesses (15) so as to be housed in the recesses (15). At least portions of the leading-out parts (22) face the recesses (15), and the thickness (t1) of the leading-out parts (22) is less than the thickness (t2) or the wire diameter (di) of a wire of the coil part (21).

Description

[Technical Field]

[0001] The present disclosure relates to inductors and methods for manufacturing inductors. [Background technology]

[0002] Inductors are used in, for example, DC-DC converter devices for the purposes of stepping up and down power supply voltages and smoothing direct currents. In recent years, the currents used in electronic devices have become larger, creating a demand for inductors used in DC-DC converter devices with higher magnetic saturation currents. Patent Document 1 discloses an inductor that includes a coil portion, multiple exterior members surrounding the coil portion, and terminal electrodes connected to the coil portion and extending to the bottom surface of the exterior members. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-129253 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional inductors, the magnetic saturation current may decrease depending on the shape of the exterior member. An object of the present disclosure is to provide an inductor that can suppress the decrease in magnetic saturation current. [Means for solving the problem]

[0005] An inductor according to one aspect of the present disclosure includes: an exterior member including a magnetic material and having a bottom surface and a side surface connected to the bottom surface; and a current-carrying member including a metal material and partially covered by the exterior member, wherein the current-carrying member is covered by the exterior member. U-shapedThe coil portion has a coil section, lead-out sections connected to both ends of the coil portion and extending toward the bottom surface while being covered by the exterior member, and a terminal electrode section connected to the lead-out sections and exposed from the bottom surface of the exterior member, wherein the side surface of the exterior member has a recess that is recessed from the side surface into the exterior member and connected to the bottom surface, and the terminal electrode section extends toward the recess while following the bottom surface, and Side The lead-out portion is bent toward the recessed portion and accommodated in the recessed portion, and at least a part of the lead-out portion faces the recessed portion, and the thickness of the lead-out portion is smaller than the wire diameter or thickness of the wire of the coil portion. Furthermore, the thickness of the exterior member between the lead-out portion and the recess is greater than the thickness of the exterior member between the straight portion of the U-shaped coil portion and the side surface of the exterior member.

[0006] Furthermore, a method for manufacturing an inductor according to an aspect of the present disclosure includes: Manufacture the above inductor The method includes pressing both ends of a metal wire using a press die to form a metal wire having a flat shape thinner than the main body on both sides of the main body of the metal wire. The aforementioned Derivation part and The aforementioned a current-carrying member forming step for forming a terminal electrode portion; and a molding die for compression-molding the magnetic material so as to cover the main body portion and the lead-out portion but not the terminal electrode portion, thereby forming the exterior member and connecting the side surface of the exterior member to the bottom surface. The aforementioned The method includes a compression molding step of forming a recess, and a bending step of aligning the terminal electrode portion from the bottom surface of the exterior member toward the recess and further bending the terminal electrode portion to be housed in the recess. [Effects of the Invention]

[0007] According to the inductor etc. of the present disclosure, it is possible to suppress a decrease in magnetic saturation current. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of an inductor of a comparative example. [Figure 2] FIG. 2 is a front view, a side view, and a bottom view of the inductor according to the embodiment. [Figure 3] FIG. 3 is a cross-sectional view of the inductor according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing another example of an inductor according to an embodiment. [Figure 5] FIG. 5 is a flowchart showing a method for manufacturing an inductor according to an embodiment. [Figure 6] FIG. 6 is a diagram illustrating a current-carrying member forming step in the method for manufacturing an inductor according to the embodiment. [Figure 7] FIG. 7 is a diagram illustrating a coil portion forming step in the method for manufacturing an inductor according to the embodiment. [Figure 8] FIG. 8 is a diagram illustrating a compression molding step in the method for manufacturing an inductor according to the embodiment. [Figure 9] FIG. 9 is a diagram illustrating a bending step in the method for manufacturing an inductor according to the embodiment. [Figure 10] FIG. 10 is a cross-sectional view of an inductor according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Background to this disclosure) As mentioned above, in recent years, the currents used in electronic devices have become larger, requiring inductors with higher magnetic saturation currents. At the same time, there is a need to reduce the mounting area of ​​the inductor on the circuit board on which the inductor is mounted, while also ensuring the strength of the connection between the inductor and the circuit board.

[0010] Fig. 1 is a cross-sectional view of an inductor 500 of a comparative example. The inductor 500 shown in Fig. 1(a) is similar to the inductor of Patent Document 1, and includes a coil portion 521, an exterior member 510 surrounding the coil portion 521, and a terminal electrode portion 523 connected to the coil portion 521. The terminal electrode portion 523 is formed so as to extend along a bottom surface 511 of the exterior member 510 toward an outer side surface 512 of the exterior member 510.

[0011] In this inductor 500, terminal electrode portion 523 exposed from exterior member 510 is formed only on bottom surface 511 of exterior member 510. Therefore, when inductor 500 is mounted on a circuit board, a fillet cannot be formed sufficiently by solder, which poses a problem in that the connection strength of inductor 500 to the circuit board cannot be ensured.

[0012] 1(b), for example, it is conceivable to increase the length of the metal plate constituting terminal electrode portion 523, bend the metal plate from bottom surface 511 so as to contact side surface 512, and form terminal electrode portion 523 also on side surface 512. In this way, a fillet is formed by solder using terminal electrode portion 523 formed on side surface 512, and the connection strength of inductor 500 to the circuit board can be ensured. However, if terminal electrode portion 523 is provided on side surface 512 of exterior member 510, there is a problem in that the mounting area of ​​inductor 500 increases by the amount of the increased thickness of terminal electrode portion 523.

[0013] 1(c), it is conceivable to solve this problem by providing a recess 515 on the side surface 512 of the exterior member 510 and accommodating the terminal electrode portion 523 in the recess 515. However, providing the recess 515 on the side surface 512 of the exterior member 510 reduces the thickness of the exterior member 510 between the recess 515 and the coil portion 521, making magnetic saturation more likely to occur. This poses a problem of a decrease in the magnetic saturation current of the inductor 500.

[0014] In contrast, the inductor of the present disclosure has the following configuration to suppress a decrease in the magnetic saturation current.

[0015] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0016] Note that the embodiments described below each illustrate a specific example of the present disclosure. The numerical values, shapes, materials, components, component placement positions, connection configurations, steps, and step sequences shown in the following embodiments are examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not recited in independent claims are described as optional components.

[0017] Each figure also shows three mutually orthogonal axes, the X-axis, the Y-axis, and the Z-axis, which are used for explanation purposes as needed. Each axis is added for explanation purposes only and does not limit the direction or posture in which the inductor is used.

[0018] (Embodiment) [composition] An inductor according to an embodiment will be described with reference to Figures 2 and 3. An inductor is a passive element that stores electrical energy flowing through a current-carrying member as magnetic energy.

[0019] Fig. 2 is a front view, a side view, and a bottom view of the inductor 100 according to the embodiment. Fig. 3 is a cross-sectional view of the inductor 100, in which (a) of Fig. 3 is a cross-sectional view taken along line iii-iii of Fig. 2, (b) of Fig. 3 is a transverse cross-sectional view of the wire of the coil portion 21, and (c) of Fig. 3 is a transverse cross-sectional view of the lead-out portion 22.

[0020] As shown in FIGS. 2 and 3, the inductor 100 includes an exterior member 10 and a current-carrying member 20 that is partially covered by the exterior member 10.

[0021] As an example, the inductor 100 is a rectangular parallelepiped metal composite, and the approximate outer shape is determined by the shape of the exterior member 10. The exterior member 10 can be formed into any shape by molding. In other words, the inductor 100 can be realized in any shape depending on the shape of the exterior member 10 during molding. The inductor 100 of this embodiment is configured with an exterior member 10 that has a dimension in the X-axis direction of 9 mm to 10 mm, a dimension in the Y-axis direction of 4.4 mm to 6 mm, and a dimension in the Z-axis direction of 6 mm to 10 mm.

[0022] The exterior member 10 is an outer shell of the inductor 100 and covers a portion of the current-carrying member 20. The exterior member 10 is, for example, a powder magnetic core made of a metal magnetic powder and a resin material. The exterior member 10 may be made of any magnetic material, such as ferrite, or other materials. The metal magnetic powder is a particulate material having a predetermined elemental composition, such as an Fe-Si-Al-based, Fe-Si-based, Fe-Si-Cr-based, or Fe-Si-Cr-B-based material. The resin material is selected from materials such as silicone that can insulate the particles of the metal magnetic powder while binding them together to maintain a certain shape.

[0023] The exterior member 10 has, for example, a rectangular parallelepiped shape and has a bottom surface 11, four side surfaces connected to the bottom surface 11, and a top surface 13 connected to the four side surfaces and facing away from the bottom surface 11. The four side surfaces are composed of two side surfaces 12a facing away from each other in the X-axis direction and two side surfaces 12b facing away from each other in the Y-axis direction. Each of the four side surfaces 12a, 12b has a flat surface perpendicular to the bottom surface 11. Each of the two side surfaces 12a has a recess 15 that is recessed from the side surface 12a toward the inside of the exterior member 10 and connected to the bottom surface 11.

[0024] The recesses 15 are recesses formed at the intersection of the bottom surface 11 and the side surface 12a of the exterior member 10. The two recesses 15 formed corresponding to each side surface 12a are located on both outer sides of the exterior member 10 in the X-axis direction. The recesses 15 have a recess plane 15a parallel to the side surface 12a. The recess plane 15a is part of the outer contour of the exterior member 10.

[0025] The current-carrying member 20 includes a coil portion 21, a plurality of lead-out portions 22 connected to both ends of the coil portion 21, and a plurality of terminal electrode portions 23 connected to each of the lead-out portions 22. The current-carrying member 20 of this embodiment is composed of one coil portion 21, two lead-out portions 22, and two terminal electrode portions 23. The current-carrying member 20 is made of a material selected from metal materials such as aluminum, copper, silver, and gold, as well as alloys made of metals and other substances. The coil portion 21, lead-out portions 22, and terminal electrode portions 23 are names given to respective portions formed by processing a single member made of the same material. Below, each portion will be described in the order of the terminal electrode portion 23, the coil portion 21, and the lead-out portion 22.

[0026] Terminal electrode portion 23 is a portion that is not covered by exterior member 10 and is exposed from bottom surface 11 of exterior member 10. Terminal electrode portion 23 extends along bottom surface 11 of exterior member 10 toward recess 15 in side surface 12a, and is bent from bottom surface 11 toward recess 15 to be housed in recess 15. For example, when inductor 100 is mounted on a circuit board, terminal electrode portion 23 is connected to a land on the circuit board via solder, and a fillet of solder is formed on terminal electrode portion 23 housed in recess 15.

[0027] The coil portion 21 is a portion covered by the exterior member 10. The number of turns of the coil portion 21 is, for example, 0.5 turns or more and less than 1.0 turn. The number of turns of the coil portion 21 shown in Figures 2 and 3 is 0.5 turns. The coil portion 21 has a U-shape and is formed, for example, by bending a metal wire. The cross section of the metal wire that constitutes the coil portion 21 is circular, and the aspect ratio of the cross section is 1:1.

[0028] The coil part 21 is arranged such that the winding axis a1 of the coil part 21 is along the Y-axis direction. Also, the coil part 21 is provided on the top surface 13 side rather than the lead-out part 22 described later, and is surrounded by the top surface 13 and the side surfaces 12a and 12b. The coil part 21 has a curved part wound in 0.5 turns and a straight part connected to the curved part. The straight part of the coil part 21 faces the side surface 12a of the exterior member 10 and is connected to the lead-out part 22.

[0029] The lead-out part 22 is also a part covered by the exterior member 10. The lead-out part 22 is a lead-out conductor for connecting the coil part 21 to the terminal electrode part 23, and is provided so as to extend from both ends of the coil part 21 toward the bottom surface 11 side of the exterior member 10. Note that the lead-out part 22 also has a function of generating an inductance component, similar to the coil part 21.

[0030] The lead-out part 22 is located between the two recesses 15 in the X-axis direction, and at least a part thereof faces the recess 15 of the exterior member 10. Specifically, the lead-out part 22 is provided on the axis b1 of the energization member 20 and has a lead-out plane 22a facing the recess plane 15a of the recess 15. Also, the lead-out part 22 has a thickness in the direction perpendicular to the side surface 12a, that is, in the X-axis direction, and has a width in the direction parallel to both the side surface 12a and the bottom surface 11, that is, in the Y-axis direction. The lead-out part 22 has a flat shape or a plate shape. For example, the width w1 of the lead-out part 22 is 5 times or more and 10 times or less the thickness t1 of the lead-out part 22.

[0031] In the present embodiment, the thickness t1 of the lead-out part 22 is smaller than the wire diameter di of the wire of the coil part 21 (t1 < di). Also, the width w1 of the lead-out part 22 is larger than the wire diameter di of the wire of the coil part 21 (w1 > di). For example, the wire diameter di of the wire of the coil part 21 is appropriately selected from the range of 1.3 mm or more and 1.8 mm or less, the thickness t1 of the lead-out part 22 is 0.4 mm, and the width w1 is 2.5 mm.

[0032] Further, the amount of reduction in the thickness of the lead-out portion 22 with respect to the coil portion 21 is larger than the amount of reduction in the thickness of the exterior member 10 in the recess 15. Specifically, when the difference between the thickness t1 of the lead-out portion 22 and the wire diameter di of the wire of the coil portion 21 is T (T = di - t1), and the depth of the recess 15 that is recessed inward from the side surface 12a of the exterior member 10 is dp, it has a relationship of T / 2 ≥ dp. For example, T / 2 is 0.45 mm or more and 0.7 mm or less, and the depth dp of the recess 15 is 0.3 mm.

[0033] Thus, in this embodiment, the thickness t1 of the lead-out portion 22 is smaller than the wire diameter di of the wire of the coil portion 21. According to this configuration, it is possible to prevent the thickness of the exterior member 10 between the lead-out portion 22 and the recess 15 from becoming thinner than necessary. Thereby, it is possible to suppress magnetic saturation from occurring in the exterior member 10 between the lead-out portion 22 and the recess 15.

[0034] In the above, an example in which the cross-section of the wire of the coil portion 21 is circular has been shown, but it is not limited thereto, and the cross-section may be square (see FIG. 4).

[0035] FIG. 4 is a cross-sectional view showing another example of the inductor 100 according to the embodiment. FIG. 4(a) is a cross-sectional view of the inductor 100 as viewed from the Y-axis direction, FIG. 4(b) is a cross-sectional view of the wire of the coil portion 21, and FIG. 4(c) is a cross-sectional view of the lead-out portion 22.

[0036] As shown in FIG. 4, even when the cross-section of the wire of the coil portion 21 is square, the lead-out portion 22 and the coil portion 21 have the same dimensional relationship. Specifically, the thickness t1 of the lead-out portion 22 is thinner than the thickness t2 of the wire of the coil portion 21 (t1 < t2), and the width w1 of the lead-out portion 22 may be wider than the width w2 of the wire of the coil portion 21 (w1 > w2). The difference T between the thickness t1 of the lead-out portion 22 and the thickness t2 of the wire of the coil portion 21 is represented by T = t2 - t1, and it may have a relationship of T / 2 ≥ dp with respect to the depth dp of the recess 15.

[0037] [Manufacturing Method] Next, a method for manufacturing the above-described inductor 100 will be described with reference to FIG. 5 and also with reference to FIGS. 6 to 9 as appropriate.

[0038] Fig. 5 is a flowchart showing a method for manufacturing the inductor 100 according to the embodiment. As shown in Fig. 5, the method for manufacturing the inductor 100 includes a current-carrying member forming step S101, a coil portion forming step S102, a compression molding step S103, and a bending step S104.

[0039] 6A and 6B are diagrams illustrating the current-carrying member forming step S101 in the manufacturing method of the inductor 100. Fig. 6A shows the metal wire 120 before press working, and Fig. 6B and Fig. 6C show the current-carrying member 20 formed by press working the metal wire 120.

[0040] The current-carrying member forming step S101 is a step of forming the current-carrying member 20 integrally including the coil portion 21, the lead-out portion 22, and the terminal electrode portion 23 from the metal wire 120.

[0041] The metal wire 120 is a single copper wire extending in the direction of the axis b1 and has a circular cross section (see FIG. 6(a)). In this process, first, both ends of the metal wire 120 are pressed using a press die (not shown). By pressing, flat portions 122 having flat surfaces 122a are formed on both outer sides of the main body 121 of the metal wire 120 (see FIG. 6(b)). The main body 121 corresponds to the coil portion 21, and the flat portions 122 correspond to the lead-out portion 22 and the terminal electrode portion 23. The flat portions 122 are formed on the axis b1 of the metal wire 120 by compressing the metal wire 120 from above and below. The flat portions 122 are processed so that the thickness t1 of the flat portions 122 is smaller than the wire diameter di of the main body 121. The axis b1 of the metal wire 120 is the same as the axis b1 of the current-carrying member 20.

[0042] The flattened flat portion 122 has three outer sides cut to adjust the dimensions in the width direction and the axis b1 direction (longitudinal direction) (see FIG. 6(c)). The width w1 of the flat portion 122 after cutting is larger than the wire diameter di of the main body portion 121. The current-carrying member 20 is formed by these press processes and cuts.

[0043] 7 is a diagram illustrating the coil portion forming step S102 in the manufacturing method of the inductor 100. In this step, the coil portion 21 is formed by winding the center of the current-carrying member 20, i.e., the main body portion 121 of the metal wire 120. In this embodiment, the coil portion 21 is formed by winding the main body portion 121 in a U-shape by 0.5 turns. After winding, the flat portions 122 connected to both ends of the coil portion 21 face each other.

[0044] FIG. 8 is a diagram illustrating the compression molding step S103 of the manufacturing method for the inductor 100. In this step, a magnetic material is compression molded using a molding die (not shown). Specifically, the entire main body 121 and a portion of the flat portion 122 are covered with the magnetic material, and the compression molding is performed so that the remaining portion of the flat portion 122 is not covered with the magnetic material, thereby forming the exterior member 10. The portion of the flat portion 122 that is covered with the exterior member 10 becomes the lead-out portion 22, and the other portion of the flat portion 122 that is not covered with the exterior member 10 becomes the terminal electrode portion 23. In this step, simultaneously with the compression molding, a recess 15 that connects to the bottom surface 11 is formed in the side surface 12a of the exterior member 10. The recess 15 is formed by providing a protrusion that protrudes inward on the inner wall of the molding die.

[0045] In the compression molding step S103, compression molding is performed in a state where the coil portion 21 is placed in a molding die so that the winding axis a1 of the coil portion 21 is aligned with the compression direction P1 of the compression molding. Furthermore, compression molding is performed in a state where the lead-out portion 22 is placed in a molding die so that the plane 122a of the flat portion 122, i.e., the plane of the lead-out portion 22 (lead-out portion plane 22a) is aligned with the compression direction P1 of the compression molding, more specifically, so that the width direction of the lead-out portion 22 is aligned with the compression direction P1. The pressure during compression molding is, for example, 5 ton / cm 2and the heat setting temperature is, for example, 185° C. The compression molding may be injection or transfer molding.

[0046] After compression molding, the terminal electrode portion 23 that is exposed and not covered by the exterior member 10 protrudes perpendicularly to the bottom surface 11 of the exterior member 10. The terminal electrode portion 23 is subjected to solder plating or the like as necessary.

[0047] 9 is a diagram illustrating the bending step S104 of the manufacturing method of the inductor 100. In this step, first, as shown in FIG. 9(a), the terminal electrode portion 23 is bent at a right angle toward the bottom surface 11, and the terminal electrode portion 23 is aligned from the bottom surface 11 toward the recess 15 of the exterior member 10. Next, as shown in FIG. 9(b), the remaining portion of the terminal electrode portion 23 excluding the portion aligned along the bottom surface 11 is bent at a right angle to be accommodated in the recess 15. In this way, the terminal electrode portion 23 is provided on the side surface 12a of the inductor 100. The inductor 100 is manufactured by the current-carrying member forming step S101, the coil portion forming step S102, the compression molding step S103, and the bending step S104.

[0048] [Effects, etc.] As described above, inductor 100 according to this embodiment includes exterior member 10, which contains a magnetic material and has bottom surface 11 and side surface 12a connected to bottom surface 11, and current-carrying member 20, which contains a metal material and is partially covered by exterior member 10. Current-carrying member 20 includes coil portion 21 covered by exterior member 10, lead-out portions 22 connected to both ends of coil portion 21 and extending toward bottom surface 11 while being covered by exterior member 10, and terminal electrode portion 23 connected to lead-out portion 22 and exposed from bottom surface 11 of exterior member 10. Side surface 12a of exterior member 10 is provided with recess 15, which is recessed from side surface 12a into exterior member 10 and connected to bottom surface 11. Terminal electrode portion 23 extends along bottom surface 11 toward recess 15 and is bent from bottom surface 11 toward recess 15 to be accommodated in recess 15. At least a part of the lead-out portion 22 faces the recess 15, and the thickness t1 of the lead-out portion 22 is smaller than the wire diameter di or the thickness t2 of the wire of the coil portion .

[0049] In this way, by making the thickness t1 of the lead-out portion 22 smaller than the wire diameter di or thickness t2 of the wire of the coil portion 21, it is possible to prevent the thickness of the exterior member 10 between the lead-out portion 22 and the recess 15 from becoming unnecessarily thin. This prevents magnetic saturation from occurring in the exterior member 10 between the lead-out portion 22 and the recess 15, and prevents a decrease in the magnetic saturation current of the inductor 100. Furthermore, by providing the recess 15 on the side surface 12a of the exterior member 10 and accommodating a portion of the terminal electrode portion 23 in the recess 15, it is possible to prevent an increase in the mounting area of ​​the inductor 100. Furthermore, by providing the terminal electrode portion 23 not only on the bottom surface 11 but also on the recess 15 on the side surface 12a, it is possible to form a fillet using solder when the inductor 100 is mounted on a circuit board, for example. This ensures the connection strength of the inductor 100 to the circuit board.

[0050] The outlet portion 22 may also have a flattened shape.

[0051] In this way, since the lead-out portion 22 has a flat shape, it is possible to ensure the thickness of the exterior member 10 between the lead-out portion 22 and the recess 15. This makes it possible to suppress magnetic saturation in the exterior member 10 between the lead-out portion 22 and the recess 15, and to suppress a decrease in the magnetic saturation current of the inductor 100.

[0052] The recess 15 may have a recess plane 15a parallel to the side surface 12a, and the lead-out portion 22 may have a lead-out portion plane 22a facing the recess plane 15a.

[0053] This configuration ensures a sufficient thickness of the exterior member 10 between the lead-out portion flat surface 22a and the recessed portion flat surface 15a, thereby preventing magnetic saturation in the exterior member 10 between the lead-out portion 22 and the recessed portion 15 and preventing a decrease in the magnetic saturation current of the inductor 100.

[0054] Furthermore, the lead-out portion 22 may have a thickness in a direction perpendicular to the side surface 12a, and when the difference between the thickness t1 of the lead-out portion 22 and the wire diameter di or thickness t2 of the wire of the coil portion 21 is T and the depth to which the recess 15 is recessed into the inside of the side surface 12a is dp, T / 2≧dp may be satisfied.

[0055] This configuration reliably prevents the thickness of the exterior member 10 between the lead-out portion 22 and the recess 15 from becoming thin. This prevents magnetic saturation from occurring in the exterior member 10 between the lead-out portion 22 and the recess 15, and prevents the magnetic saturation current of the inductor 100 from decreasing.

[0056] Furthermore, the width w1 of the lead-out portion 22 may be larger than the wire diameter di or the width w2 of the wire of the coil portion 21.

[0057] According to this configuration, for example, the cross-sectional area of ​​the lead-out portion 22 can be made larger than when the width w1 is the same as the wire diameter di or the width w2, thereby suppressing DC resistance loss in the lead-out portion 22 and preventing a decrease in the inductance value of the inductor 100.

[0058] The aspect ratio of the cross section of the wire of the coil portion 21 may be 1:1.

[0059] According to this configuration, the magnetic path length can be made shorter and the magnetic efficiency can be improved compared to, for example, coil portion 21 in which the cross section of the wire is plate-shaped.

[0060] The method for manufacturing an inductor according to this embodiment is a method for manufacturing an inductor 100 including an exterior member 10 containing a magnetic material and having a bottom surface 11 and a side surface 12a connected to the bottom surface 11, and a current-carrying member 20 partially covered by the exterior member 10. The method for manufacturing the inductor 100 includes a current-carrying member forming step S101 in which a press die is used to press both ends of a metal wire 120 to form lead-out portions 22 and terminal electrode portions 23 that are thinner and flatter than the main body portion 121 on both outer sides of the main body portion 121 of the metal wire 120, a compression molding step S103 in which a molding die is used to compression-molde a magnetic material so as to cover the main body portion 121 and the lead-out portions 22 but not the terminal electrode portions 23, thereby forming the exterior member 10 and forming recesses 15 in the side surfaces 12a of the exterior member 10 that are connected to the bottom surface 11, and a bending step S104 in which the terminal electrode portions 23 are aligned from the bottom surface 11 of the exterior member 10 toward the recesses 15 and further bent to be accommodated in the recesses 15.

[0061] In this way, by making the lead-out portion 22 thinner than the main body portion 121 of the metal wire 120, the inductor 100 can be manufactured without reducing the thickness of the exterior member 10 outside the lead-out portion. This prevents magnetic saturation from occurring in the exterior member 10 outside the lead-out portion 22, and prevents a decrease in the magnetic saturation current of the inductor 100. Furthermore, by accommodating a portion of the terminal electrode portion 23 in the recess 15 on the side surface 12a of the exterior member 10, an increase in the mounting area of ​​the inductor 100 can be prevented. Furthermore, by providing the terminal electrode portion 23 not only on the bottom surface 11 but also on the recess 15 on the side surface 12a, a fillet can be formed by solder when the inductor 100 is mounted on a circuit board, for example. This ensures the connection strength of the inductor 100 to the circuit board.

[0062] In the compression molding step S103, the compression molding may be performed in a state where the flattened outlet portion 22 is placed in the molding die so that the plane of the outlet portion 22 is aligned with the compression direction P1 of the compression molding.

[0063] This allows the magnetic material to flow more easily along the lead-out portion 22, thereby increasing the density of the exterior member 10 after compression molding. This makes it less likely for magnetic saturation to occur in the exterior member 10, and prevents the magnetic saturation current of the inductor 100 from decreasing.

[0064] Furthermore, the method for manufacturing an inductor further includes a coil portion forming step S102 in which, before the compression molding step S103, the main body portion 121 of the metal wire 120 is wound by 0.5 turns or more but less than 1.0 turns to form the coil portion 21, and in the compression molding step S103, compression molding may be performed in a state in which the coil portion 21 is placed in a molding die so that the winding axis a1 of the coil portion 21 is along the compression direction P1 of the compression molding.

[0065] This allows the magnetic material to easily penetrate into the inside of the coil portion 21, increasing the density of the exterior member 10 after compression molding. This makes it difficult for magnetic saturation to occur in the exterior member 10, and prevents the magnetic saturation current of the inductor 100 from decreasing.

[0066] (Other embodiments, etc.) Although the inductors and the like according to the embodiments of the present disclosure have been described above, the present disclosure is not limited to these embodiments.

[0067] For example, the present disclosure also includes an electrical product or an electrical circuit using the above-described inductor. Examples of electrical products include a power supply device equipped with the above-described inductor.

[0068] For example, in the above-described inductor 100, the thickness of the exterior member 10 between the lead-out portion 22 and the recess 15 may be thicker than the thickness of the exterior member 10 between the straight portion of the coil portion 21 and the side surface 12a. With this configuration, magnetic saturation can be suppressed in the exterior member 10 between the lead-out portion 22 and the recess 15.

[0069] For example, while the above example illustrates the flat portion 122 being formed on the axis b1 of the metal wire 120, the present invention is not limited thereto, and the flat portion 122 may be formed at a position offset from the axis b1 of the metal wire 120. For example, the flat portion 122 can be formed by biasing downward by pressing the metal wire 120 from above while it is placed on a base. In other words, the lead-out portion 22 does not necessarily have to be provided on the axis b1 of the current-carrying member 20. As shown in FIG. 10 , the lead-out portion 22 may be provided closer to the inside of the outer casing 10 than the axis b1, i.e., closer to the center line c1 of the outer casing 10. In this case, the inductor 100 may be configured such that the difference T between the thickness t1 of the lead-out portion 22 and the wire diameter di of the wire of the coil portion 21 is equal to or greater than the depth dp of the recess 15 (T≧dp).

[0070] Furthermore, the present disclosure is not limited to the embodiment, and various modifications conceivable by those skilled in the art to the present embodiment and forms constructed by combining components of different embodiments may also be included within the scope of one or more aspects, as long as they do not deviate from the spirit of the present disclosure. [Industrial Applicability]

[0071] INDUSTRIAL APPLICABILITY An inductor according to the present disclosure is useful as an inductor used in a DC-DC converter device. [Explanation of symbols]

[0072] 10 Exterior materials 11 Bottom 12, 12a, 12b side 13 Top 15 recess 15a Recessed plane 20 Conductive materials 21 Coil section 22 Derivation part 22a Derivation part plane 23 Terminal electrode section 100 inductor 120 Metal Wire 121 Main body 122 Flat part a1 Winding shaft b1 axis di Diameter of the wire in the coil dp Recess depth P1 Compression direction T Difference between the thickness of the lead-out part and the wire diameter or thickness of the coil part t1 Thickness of the outlet t2 Thickness of the wire in the coil w1 Width of lead-out part w2 Width of the coil wire

Claims

1. an exterior member including a magnetic material and having a bottom surface and a side surface connected to the bottom surface; a current-carrying member including a metal material and partially covered by the exterior member; Equipped with the current-carrying member has a U-shaped coil portion covered by the exterior member, lead-out portions connected to both ends of the coil portion and extending toward the bottom surface while being covered by the exterior member, and a terminal electrode portion connected to the lead-out portions and exposed from the bottom surface of the exterior member, a recessed portion is provided on the side surface of the exterior member, the recessed portion being recessed from the side surface to the inside of the exterior member and connected to the bottom surface; the terminal electrode portion extends toward the recess along the bottom surface, and is bent from the bottom surface toward the recess of the side surface to be accommodated in the recess, At least a portion of the lead-out portion faces the recessed portion, The thickness of the lead-out portion is smaller than the wire diameter or thickness of the wire of the coil portion, a thickness of the exterior member between the lead-out portion and the recessed portion is greater than a thickness of the exterior member between a straight portion of the U-shaped coil portion and the side surface of the exterior member; Inductor.

2. The outlet portion has a flat shape.

10. The inductor of claim 1.

3. The recess has a recess plane parallel to the side surface, The lead-out portion has a lead-out plane that faces the recess plane.

3. The inductor according to claim 1 or 2.

4. The lead-out portion has a thickness in a direction perpendicular to the side surface, The difference between the thickness of the lead-out portion and the wire diameter or thickness of the wire of the coil portion is defined as T, When the depth of the recessed portion recessed inwardly of the side surface is dp, T / 2≧dp The inductor according to any one of claims 1 to 3.

5. The width of the lead-out portion is larger than the wire diameter or width of the wire material of the coil portion. The inductor according to any one of claims 1 to 4.

6. The aspect ratio of the cross section of the wire of the coil portion is 1:

1. The inductor according to any one of claims 1 to 5.

7. A method for manufacturing the inductor according to claim 1, comprising: a current-carrying member forming step in which both ends of a metal wire are pressed using a press die to form the lead-out portion and the terminal electrode portion, which are thinner and flatter than the main body portion, on both sides of the main body portion of the metal wire; a compression molding process in which the magnetic material is compression-molded using a molding die so as to cover the main body portion and the lead-out portion but not the terminal electrode portion, thereby forming the exterior member and forming the recessed portion connected to the bottom surface on the side surface of the exterior member; a bending step of aligning the terminal electrode portion from the bottom surface of the exterior member toward the recessed portion and further bending the terminal electrode portion so as to be housed in the recessed portion; A method for manufacturing an inductor comprising:

8. In the compression molding step, the compression molding is performed in a state where the flattened outlet portion is disposed in the molding die so that the plane of the outlet portion is along the compression direction of the compression molding. The method for manufacturing an inductor according to claim 7 .

9. Furthermore, the method includes a coil portion forming step of forming the coil portion by winding the main body portion of the metal wire by 0.5 turns or more and less than 1.0 turns before the compression molding step, In the compression molding step, the compression molding is performed in a state where the coil portion is placed in the molding die so that the winding axis of the coil portion is aligned with the compression direction of the compression molding. The method for manufacturing an inductor according to claim 7 or 8.

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