Inductor and method for manufacturing the same

Abstract

This inductor is equipped with a magnetic core, a coil element which is embedded in the magnetic core and has an end section projecting from an end surface of the magnetic core, and an electrode member which is mechanically and electrically connected to the end section of the coil element. The electrode member bends along an end surface and a bottom surface of the magnetic core, and has an end surface section which faces said end surface and a bottom surface section which faces said bottom surface. The end section of the coil element overlaps and is connected to the electrode member. The end surface of the magnetic core has a first region which is connected to the bottom surface of the magnetic core and is provided with the end surface section of the electrode member, and two second regions which are connected to the bottom surface of the magnetic core and are positioned on both sides of the first region so as to sandwich said first region therebetween. The angle formed between the bottom surface of the magnetic core and the two second regions on the end surface of the magnetic core is smaller than 90.0° and greater than the angle formed between the bottom surface of the magnetic core and the outer surface of the end surface section of the electrode member.

Description

Technical Field

[0001] The present disclosure relates to an inductor used in various electronic devices and a method for manufacturing the same.

Background Art

[0002] In recent years, with the improvement in performance of electronic devices, there is a desire for miniaturization, and at the same time, the current used tends to increase. There is a need for an inductor that satisfies both of these requirements. Therefore, an inductor has been proposed in which a coil element is embedded in a mixed powder of a metal magnetic powder and a binder made of a thermosetting resin and is compression-molded to form a magnetic core. In addition, in order to reduce the cost of forming an external electrode, an inductor has also been proposed in which a member serving as an external electrode is formed simultaneously when forming a magnetic core.

[0003] An inductor similar to the above inductor is disclosed in, for example, Patent Document 1.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] In a conventional inductor, when a member serving as an external electrode is placed in a mold and compression-molded, when the molded product is taken out of the mold, the external electrode may rub against the wall surface of the mold and the external electrode may be damaged. If the external electrode is damaged, there may be a problem with solderability.

[0006] <00The inductor comprises a magnetic core, a coil element embedded in the magnetic core and having an end protruding from the end face of the magnetic core, and an electrode member electrically and mechanically connected to the end of the coil element. The electrode member is bent along the end face and bottom face of the magnetic core and has an end face portion facing the end face of the magnetic core and a bottom face portion facing the bottom face of the magnetic core. The ends of the coil element are overlapped and connected to the electrode member. The end face of the magnetic core has a first region connected to the bottom face of the magnetic core and where the end face portion of the electrode member is provided, and two second regions connected to the bottom face of the magnetic core and located on both sides of the first region with the first region in between. The angle between the bottom face of the magnetic core and the two second regions of the end face of the magnetic core is greater than the angle between the bottom face of the magnetic core and the outer surface of the end face portion of the electrode member, and less than 90.0°.

[0007] This inductor is small, capable of handling high power, and has excellent solderability. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view of an inductor in one embodiment of the present disclosure. [Figure 2] Figure 2 is a cross-sectional view of the inductor shown in Figure 1 along line II-II. [Figure 3] Figure 3 is a cross-sectional view illustrating the method for manufacturing an inductor in an embodiment. [Figure 4] Figure 4 is a cross-sectional view illustrating the manufacturing method of an inductor in an embodiment. [Figure 5] Figure 5 is a cross-sectional view illustrating the manufacturing method of an inductor in an embodiment. [Figure 6] Figure 6 is a cross-sectional view illustrating the method for manufacturing an inductor in an embodiment. [Modes for carrying out the invention]

[0009] Hereinafter, an inductor according to one embodiment of the present invention will be described with reference to the drawings. Figure 1 is a perspective view of an inductor 501 according to one embodiment of the present disclosure, and Figure 2 is a cross-sectional view of the inductor 501 along line II-II. The inductor 501 comprises a magnetic core 11, a coil element 12 embedded in the magnetic core 11, and an electrode member 13 electrically and mechanically connected to the coil element 12. For clarity, the outer shape of the magnetic core 11 is shown with a dashed line in Figure 1.

[0010] The coil element 12 consists of a wound insulated conductor with a diameter of approximately 0.3 mm. The portion of the insulating coating 12c located at the end 12a of the coil element 12 is peeled off, and the end 12a is crushed to have a flattened shape with a thickness of approximately 0.2 mm. The magnetic core 11 is formed by embedding the coil element 12 in a magnetic material powder mixture made by mixing magnetic material powder made of Fe-Si-Cr alloy and a binder made of silicone, and then pressure molding the magnetic material powder mixture. The magnetic core 11 has a rectangular parallelepiped shape with a planar shape of approximately 10 mm square and a height of approximately 5 mm. The magnetic core 11 has a bottom surface 11b, an upper surface 411a opposite to the bottom surface 11b, and end surfaces 11a, 111a, 211a, and 311a connecting the bottom surface 11b and the upper surface 411a. The end surfaces 11a and 111a are located on opposite sides of each other, and the end surfaces 211a and 311a are located on opposite sides of each other. The ends 12a of the coil element 12 protrude from the end faces 11a and 111a of the magnetic core 11. An electrode member 13 is fixed to the end face 11a (111a) of the magnetic core 11 and bent along the bottom surface 11b of the magnetic core 11. The electrode member 13 has an end face portion 13a that is provided on the end face 11a (111a) and extends along the end face 11a (111a), and a bottom face portion 13b that is provided on the bottom surface 11b and extends along the bottom surface 11b.

[0011] The end face portion 13a of the electrode member 13 located at the end face 11a is embedded in the magnetic core 11 and fixed to the magnetic core 11 by at least a portion of its thickness. The end face portion 13a of the electrode member 13 has an inner surface 13a1 facing the magnetic core 11 and an outer surface 13a2 opposite to the inner surface 13a1. The inner surface 13a1 of the end face portion 13a abuts against the region 11a1 of the end face 11a (111a) of the magnetic core 11. The outer surface 13a2 of the end face portion 13a of the electrode member 13 is provided with a recess 13d that is recessed toward the magnetic core 11 and penetrates into the magnetic core 11. The end portion 12a of the coil element 12 is superimposed on the recess 13d and electrically and mechanically connected to the electrode member 13. On the inner surface 13a1 of the electrode member 13 opposite the recess 13d, a protrusion 13e is provided that is deformed to conform to the shape of the recess 13d, and is embedded in the magnetic core 11 to a depth approximately the thickness of the end 12a of the coil element 12. By providing the protrusion 13e on the inner surface 13a1 of the electrode member 13 facing the magnetic core 11 in this way, the fixing strength of the electrode member 13 to the magnetic core 11 can be increased.

[0012] The electrode member 13 is made by punching out a flat copper plate containing 99% or more copper, and is approximately 0.15 mm thick. One surface (outer surface 13a2) of the electrode member 13 is provided with a plating layer 13f, which is nickel and then tin, while the other surface (inner surface 13a1) on the opposite side is not plated and the copper is exposed. The end 12a of the coil element 12 is electrically and mechanically connected by welding to the outer surface 13a2 of the end face portion 13a of the electrode member 13, which is provided on the end face 11a of the magnetic core 11, where the plating layer 13f is provided. The inner surface 13a1 of the end face portion 13a of the electrode member 13, which is not plated, is embedded in the magnetic core 11 and is in contact with the magnetic core 11. Because the outer surface 13a2 of the end face portion 13a of the electrode member 13 is provided with a plating layer 13f, soldering is easy. If a low-melting-point plating layer, such as tin, is present in the portion of the electrode member 13 embedded in the magnetic core 11, the plating layer may melt during reflow soldering, potentially causing reliability issues. In contrast, in the inductor 501 of this embodiment, the portion of the electrode member 13 where the plating layer 13f is provided is not embedded in the magnetic core 11, thus enabling the creation of a highly reliable inductor 501.

[0013] The angle T1 between the bottom surface 11b of the magnetic core 11 and the outer surface 13a2 of the end face portion 13a of the electrode member 13 located on the end surface 11a (111a) of the magnetic core 11 is set to approximately 86.5°. In Figure 2, the extension of the bottom surface 11b of the magnetic core 11 is shown by a dashed line, and the outer surface 13a2 of the end face portion 13a of the electrode member 13 is shown by a dashed line. The angle T2 between the bottom surface 11b of the magnetic core 11 and the regions 11a2 and 11a3 on either side of region 11a1 of the end face portion 13a of the electrode member 13 on the end face 11a of the magnetic core 11, i.e., region 11a1 of the end face 11a (111a) of the magnetic core 11, is set to approximately 89.5°. Region 11a1 of the end face 11a (111a) of the magnetic core 11 is located between regions 11a2 and 11a3. In Figure 2, the regions 11a2 and 11a3 of the end faces 11a of the magnetic core 11 are shown by dashed lines. The reference surface for the bottom face 11b of the magnetic core 11 at this time refers to the surface of the flat plate on which the magnetic core 11 is placed, with the bottom portion 13b of the electrode member 13 located at the bottom face 11b of the magnetic core 11 removed. The reason why the angle T2 between the bottom face 11b of the magnetic core 11 and the regions 11a2 and 11a3 of the end faces 11a of the magnetic core 11 on both sides of the electrode member 13 is set to approximately 89.5°, which is smaller than 90.0° (shown by the dotted line 17 in Figure 2), is to make it easier to remove the magnetic core 11 from the mold in which it was pressure-molded, and the regions 11a2 and 11a3 of the end faces 11a are slightly inclined.

[0014] When the magnetic core 11 is removed from the mold after being pressure-molded in a mold, the entire magnetic core 11 tends to expand. As a result, the end face portion 13a of the electrode member 13, which is positioned on the end face 11a (111a) of the magnetic core 11, is pressed against the mold wall with strong stress, making the end face portion 13a prone to damage. In contrast, in one embodiment of the present invention, the regions 11a2 and 11a3 of the end face 11a of the magnetic core 11 on both sides of the electrode member 13 on the end face 11a side are at an angle closer to a right angle with respect to the bottom surface 11b of the magnetic core 11 than the end face portion 13a of the electrode member 13. Therefore, even if the entire magnetic core 11 tries to expand, the regions 11a2 and 11a3 of the end face 11a of the magnetic core 11 on both sides of the electrode member 13 on the end face 11a side provide support, suppressing the expansion of the outer surface 13a2 of the end face portion 13a2 of the electrode member 13. Therefore, the end face portion 13a of the electrode member 13 on the end face 11a side of the magnetic core 11 is less likely to be damaged. Here, the outer surface 13a2 of the end face portion 13a of the electrode member 13 has a greater slope than the regions 11a2 and 11a3 of the end faces 11a of the magnetic core 11 on both sides of the electrode member 13. As a result, the pressure that would otherwise spread in the direction of the end face 11a of the magnetic core 11 during pressure molding is dispersed along the slope, thereby suppressing the expansion of the entire magnetic core 11.

[0015] It is desirable that the angle T3 (=T2-T1) between the outer surface 13a2 of the end face portion 13a of the electrode member 13 and the regions 11a2 (11a3) of the end faces 11a of the magnetic core 11 on both sides of the electrode member 13 be between 2.0° and 5.0°. If the angle T3 is smaller than 2.0°, the effect of suppressing damage to the electrode member 13 will be reduced, and if it is larger than 5.0°, it is undesirable because cracks are more likely to occur in the magnetic core 11 when the electrode member 13 is bent from the end face 11a toward the bottom face 11b of the magnetic core 11.

[0016] The inductor 501 is configured to be mounted on the mounting surface 502 facing the bottom surface 11b of the magnetic core 11. Since the end face portion 13a of the electrode member 13 is tapered in the forward direction relative to the mounting surface 502, when mounting and soldering the inductor 501, the solder easily wets the end face portion 13a of the electrode member 13, and the soldering condition can be easily checked from above.

[0017] As described above, the magnetic core 11 contains magnetic material powder and a binder mixed with the magnetic material powder, and has a bottom surface 11b and an end surface 11a (111a) connected to the bottom surface 11b. The coil element 12 is embedded in the magnetic core 11 and has an end surface 12a protruding from the end surface 11a of the magnetic core 11. The electrode member 13 is electrically and mechanically connected to the end surface 12a of the coil element 12. The electrode member 13 is bent along the end surface 11a and bottom surface 11b of the magnetic core 11 so that it has an end surface portion 13a facing the end surface 11a of the magnetic core 11 and a bottom surface portion 13b facing the bottom surface 11b of the magnetic core 11. The end surface portion 13a of the electrode member 13 has an inner surface 13a1 facing the magnetic core 11 and an outer surface 13a2 opposite to the inner surface 13a1. A recess 13d is formed on the outer surface 13a2 of the end face portion 13a of the electrode member 13, recessing toward the magnetic core 11. The end portion 12a of the coil element 12 is superimposed on the recess 13d of the electrode member 13 and connected to the electrode member 13. The inner surface 13a1 of the end face portion 13a of the electrode member 13 is embedded in the magnetic core 11. The end face 11a of the magnetic core 11 has a region 11a1 that is connected to the bottom surface 11b of the magnetic core 11 and where the inner surface 13a1 of the electrode member 13 is provided, and two regions 11a2 and 11a3 that are connected to the bottom surface 11b of the magnetic core 11 and located on both sides of region 11a1 with region 11a1 in between. The angle T2 between the bottom surface 11b of the magnetic core 11 and the two regions 11a2 and 11a3 of the end surface 11a of the magnetic core 11 is greater than the angle T1 between the bottom surface 11b of the magnetic core 11 and the outer surface 13a2 of the end surface portion 13a of the electrode member 13, and less than 90.0°.

[0018] The angle T3 between the outer surface 13a2 of the end face portion 13a of the electrode member 13 and the two regions 11a2 and 11a3 of the end face 11a of the magnetic core 11 may be 2.0° or more and 5.0° or less.

[0019] The inner surface 13a1 of the end face portion 13a of the electrode member 13 may have a convex portion 13e located on the opposite side of the concave portion 13d and projecting toward the magnetic core 11.

[0020] The electrode member 13 may further have a plating layer 13f provided on a surface (outer surface 13a2) that does not face the core 11 of the electrode member 13. In this case, a plating layer may not be provided on the surface (inner surface 13a1) of the electrode member 13 that faces the core 11.

[0021] Next, a method for manufacturing the inductor 501 will be described. FIGS. 3 to 6 are cross-sectional views for explaining the method for manufacturing the inductor 501 in the embodiment.

[0022] First, a coil element 12 is formed by spirally winding a conductive wire 12d having an insulating coating 12c provided on its surface, and pulling out both end portions 12a in opposite directions. An insulated copper wire with a diameter of about 0.3 mm is used for the conductive wire 12d. The insulating coating 12c is peeled off at the end portion 112c of the insulating coating 12c at the end portion 12a of the coil element 12, and the end portion 12a is flattened with a thickness of about 0.2 mm.

[0023] On the other hand, a flat plate provided with a plating layer 13f plated in the order of nickel and tin is punched out on one surface of a copper plate containing 99% or more of copper to obtain an electrode member 13. The electrode member 13 includes an end face portion 13a of a portion disposed on the end face 11a of the core 11 and connected to the end portion 12a of the coil element, a bottom face portion 13b of a portion connected to the end face portion 13a and disposed on the bottom face 11b of the core 11, and a support portion 13c that is connected to the bottom face portion 13b on the opposite side of the end face portion 13a and is supported by a mold when the core 11 described later is pressure-molded, and is integrally formed. The thickness of the electrode member 13 is about 0.15 mm.

[0024] Next, the end portion 12a of the coil element 12 is welded to the electrode member 13 by laser welding or the like to form a coil assembly 12p by electrically and mechanically connecting them. FIG. 4 shows a cross-section of the coil assembly 12p. A recess 13d is provided in advance by pressing on the end face portion 13a of the electrode member 13 where the end portion 12a of the coil element 12 overlaps. It is desirable to accommodate and weld the end portion 12a of the coil element 12 in the recess 13d. A convex portion 13e deformed along the shape of the recess 13d is provided on the inner surface 13a1 of the electrode member 13 facing the core 11 on the opposite side of the recess 13d.

[0025] As a welding method, for example, as shown in Figure 3, a recess 13d with a depth of approximately 0.15 mm is made in the outer surface 13a2 on which the plating layer 13f is provided, the recess 13d of the electrode member 13 is placed on top of the end 12a of the coil element 12, and laser light 16 is irradiated onto the inner surface 13a1 of the electrode member 13 which does not have the plating layer 13f. The heat generated by the laser light 16 is transferred to the opposite outer surface 13a2, melting the plating layer 13f and bringing it into close contact with the end 12a of the coil element 12, thereby transferring heat to the end 12a of the coil element 12 and welding the end 12a of the coil element 12 to the electrode member 13.

[0026] Next, the end portion 12a of the coil element 12 and the electrode member 13 are bent. In this step, the coil assembly 12p, which is formed by connecting the coil element 12 and the electrode member 13 and integrating them, is prepared to be placed into the cavity of the mold for pressure molding the magnetic core 11, which will be described later. When the magnetic core 11 of the coil assembly 12p is pressure molded, as shown in Figure 4, the end portion 12a of the coil element 12 is bent, the end portion 13a and the bottom portion 13b are formed in a straight line, and the support portion 13c is bent outward relative to the coil element 12 so as to be away from the coil element 12.

[0027] Preparations are made for forming the magnetic core 11. First, compacted magnetic powder, which is a mixture of magnetic material powder made of Fe-Si-Cr alloy and a binder made of silicone, is placed in a tablet molding die at a rate of approximately 0.25 ton / cm³. 2 By compressing with pressure, a magnetic powder tablet that easily collapses under pressure is formed. In this embodiment, a lower magnetic powder tablet for forming the lower part of the magnetic core 11 and an upper magnetic powder tablet for forming the upper part of the magnetic core 11 are created. The shape of the lower magnetic powder tablet is preferably a pot shape with an E-shaped cross-section, and it is preferable that the shape of the upper magnetic powder tablet is a flat plate shape so as to block the recess of the lower magnetic powder tablet.

[0028] Next, the magnetic core 11 is pressure-molded. Figures 5 and 6 are cross-sectional views illustrating the manufacturing method of the inductor 501. A mold 14 with a cavity 14p formed therein, and upper punches 14a and lower punches 14b, both configured to be inserted into the cavity 14p, constitute a mold 601 for pressure-molding the magnetic core 11. Figures 5 and 6 schematically show the state before pressure molding, with the upper magnetic powder tablet 15a, coil assembly 12p, and lower magnetic powder tablet 15b placed in the cavity 14p of the mold 14. Figure 5 corresponds to the cross-section shown in Figure 2 along line II-II of the inductor 501 shown in Figures 1 and 2, and Figure 6 corresponds to the cross-section shown in Figure 1 along line VI-VI of the inductor 501.

[0029] As shown in Figures 5 and 6, the upper magnetic powder tablet 15a is placed in the cavity 14p of the mold 14, then the coil assembly 12p is placed on top of it, then the lower magnetic powder tablet 15b is placed, the upper punch 14a is lowered, and the lower punch 14b is raised to approximately 4 tons / cm². 2 The magnetic powder tablets 15a and 15b are pressure-molded under pressure. Once pressurization is complete, the magnetic core 11 is formed within the cavity 14p of the mold 14, and the bottom portion 13b and support portion 13c of the electrode member 13 are outside the magnetic core 11 (cavity 14p of the mold 14). During pressure molding, the coil element 12 is supported and fixed by the mold 14 at the support portion 13c of the electrode member 13, thus making it less likely for the magnetic powder tablets 15a and 15b to shift position when pressure-molded. As for how to put the lower magnetic powder tablet 15b into the mold 14, the coil assembly 12p may be put into the mold 14 first, and then the lower magnetic powder tablet 15b may be put into the mold 14. Alternatively, the lower magnetic powder tablet 15b may be attached to the coil assembly 12p, and then the lower magnetic powder tablet 15b may be put into the mold 14.

[0030] As shown in Figure 5, on the inner wall surface 601a of the mold 14 that forms the end face 11a side of the magnetic core 11, the angle T01 between the inner wall surface 601b of the upper punch 14a (mold 601) that forms the bottom face 11b of the magnetic core 11 and the portion 601a1 of the inner wall surface 601a of the mold 14 that contacts the outer surface 13a2 of the end face portion 13a of the electrode member 13 is set to approximately 86.5°. As shown in Figure 6, the angle T02 between the inner wall surface 601b of the upper punch 14a (mold 601) that forms the bottom face 11b of the magnetic core 11 and portions 601a2 and 601a3 of the inner wall surface 601a of the mold 14 that form both sides of the end face portion 13a of the electrode member 13 is set to approximately 89.5°. In this way, by making the inclination of portion 601a1 of the inner wall surface 601a of the mold 14 that abuts the end face portion 13a of the electrode member 13 different from the inclination of portions 601a2 and 601a3 of the inner wall surface 601a of the mold 14 that form the regions 11a2 and 11a3 of the end faces 11a of the magnetic core 11 on both sides of the electrode member 13 with respect to the respective inner wall surfaces 601b, when removing the magnetic core 11 after pressure molding, even if the entire magnetic core 11 tries to expand, the portions of the inner wall surfaces of the mold 14 on both sides of the end face portion 13a of the electrode member 13 act as supports to support the outer surface 13a2 of the end face portion 13a of the electrode member 13, thereby suppressing the expansion of the outer surface 13a2 of the end face portion 13a of the electrode member 13. As a result, the end face portion 13a of the electrode member 13 on the end face 11a side of the magnetic core 11 is less likely to be damaged.

[0031] Furthermore, since the position of the end face portion 13a of the electrode member 13 is determined by the mold 14, the shape of the inductor 501 is stabilized. Therefore, when mounting and soldering the inductor 501, stable soldering is possible.

[0032] Alternatively, when inserting the coil assembly 12p, which integrates the coil element 12 and the electrode member 13, into the cavity 14p of the mold 14, the coil assembly 12p may be deformed so that the distance L13 between the end face portions 13a of the pair of electrode members 13 is reduced, and then inserted into the cavity 14p. After that, the distance L13 between the end face portions 13a of the electrode members 13 may be widened so that the outer surface 13a2 of the end face portions 13a of the electrode members 13 come into contact with the inner wall surface of the mold 14, and then the lower magnetic powder tablet 15b may be inserted and pressure molding performed. By doing so, when inserting the integrated coil element 12 and electrode member 13 into the mold 14, the end face portions 13a of the electrode members 13 may not rub against the inner wall surface 601a of the mold 14, thereby preventing damage.

[0033] After removing the pressure-molded magnetic core 11 from the mold 14, the magnetic core 11 is heat-cured, the support portion 13c of the electrode member 13 is cut, and the bottom portion 13b is bent to obtain the inductor 501.

[0034] As described above, prepare the coil assembly 12p. The coil assembly 12p comprises a coil element 12 having both ends 12a drawn out in opposite directions, and electrode members 13 electrically and mechanically connected to the ends 12a of the coil element 12. The electrode member 13 has an end face portion 13a electrically and mechanically connected to the ends 12a of the coil element 12, and a bottom face portion 13b connected to the end face portion 13a. Prepare a magnetic powder tablet 15a containing magnetic material powder and a resin mixed with the magnetic material powder. Place the magnetic powder tablet 15a and the coil assembly 12p into the mold 601. With the magnetic powder tablet 15a and the coil assembly 12p inside the mold 601, press-molde the magnetic powder tablet 15a to form the magnetic core 11. Bend the bottom face portion 13b of the electrode member 13. The magnetic core 11 has a bottom surface 11b, an end surface 11a connected to the bottom surface 11b, and an end surface 111a on the opposite side of the end surface 11a that is connected to the bottom surface 11b. The end surface 11a of the magnetic core 11 has a region 11a1 connected to the bottom surface 11b of the magnetic core 11 where the inner surface 13a1 of the end surface portion 13a of the electrode member 13 is provided, and two regions 11a2 and 11a3 connected to the bottom surface 11b of the magnetic core 11 and located on both sides of region 11a1 with region 11a1 in between. The end surface 111a of the magnetic core 11 has a region 11a1 connected to the bottom surface 11b of the magnetic core 11 where the inner surface 13a1 of the end surface portion 13a of the electrode member 13 is provided, and two regions 11a2 and 11a3 connected to the bottom surface 11b of the magnetic core 11 and located on both sides of region 11a1 with region 11a1 in between. When forming the magnetic core 11, the inner wall surface 601a of the mold 601 abuts against the outer surface 13a2 of the end face portion 13a of the electrode member 13 and the two regions 11a2 and 11a3 of the end face 11a of the magnetic core 11, and the inner wall surface 601a of the mold 601 abuts against the outer surface 13a2 of the end face portion 13a of the electrode member 13 and the two regions 11a2 of the end face 111a of the magnetic core 11.When forming the magnetic core 11, the inclination of the portion 601a1 (see Figure 5) of the inner wall surface 601a of the mold 601 that contacts the outer surface 13a2 of the end face portion 13a of the electrode member 13 is different from the inclination of the portions 601a2 and 601a3 (see Figure 6) of the inner wall surface 601a of the mold 601 that contact the two regions 11a2 and 11a3 of the end face portion 11a of the magnetic core 11 (see Figure 6) (see Figure 6) (see Figure 6) (see Figure 6) (see Figure 6) of the inner wall surface 601a of the mold 601) (see Figure 6the inclination of the portion 601a of the inner wall surface 601a of the mold 601) (see Figure 6) (see Figure 6) (see Figure 6) (the inclination of the portion 601a of the inner wall surface 601a of the mold 601) (see Figure 6) (see Figure 6) (see Figure 6)) (see Figure When forming the magnetic core 11, the inclination of the portion 601a1 of the inner wall surface 601a of the mold 601 that contacts the outer surface 13a2 of the end face 13a of the electrode member 13 is different from the inclination of the portions 601a2 and 601a3 of the inner wall surface 601a of the mold 601 that contact the two regions 11a2 of the end face 111a of the magnetic core 11 when forming the magnetic core 11, such that the angle T2 between each of the two regions 11a2 of the end face 111a of the magnetic core 11 and the bottom surface 11b of the magnetic core 11 is greater than the angle T1 between the bottom surface 11b of the magnetic core 11 and the outer surface 13a2 of the end face portion 13a of the electrode member 13, and less than 90.0°.

[0035] When inserting the coil assembly 12p and electrode member 13 into the mold 601, the coil assembly 12p may be deformed so that the distance L13 between the end face portions 13a of the electrode member 13 is reduced, and then inserted into the mold 601. After that, with the coil assembly 12p inside the mold 601, the distance L13 between the end face portions 13a of the electrode member 13 may be increased so that the end face portions 13a come into contact with the inner wall surfaces 601a of the mold 601, respectively.

[0036] A magnetic powder tablet 15b containing magnetic material powder and resin may be further prepared. When forming the magnetic core 11, the magnetic powder tablet 15a and magnetic powder tablet 15b may be pressure-molded with the magnetic powder tablet 15a, magnetic powder tablet 15b, and coil assembly 12p inside the mold 601 to form the magnetic core 11.

[0037] The step of placing the coil assembly 12p into the mold 601 may be performed after the step of placing the magnetic powder tablet 15a into the mold 601. The step of placing the magnetic powder tablet 15b into the mold 601 may be performed after the step of placing the coil assembly 12p into the mold 601.

[0038] The coil assembly 12p may be prepared as follows: A conductor 12d having a surface covered with an insulating coating 12c is wound spirally. The ends of the conductor 12d are pulled out in opposite directions, and the portions of the insulating coating 12c located at both ends of the conductor 12d are peeled off to form the coil element 12.

[0039] When preparing the coil assembly 12p, the ends 12a of the coil element 12 and the electrode member 13 may be bent.

[0040] The electrode member 13 may further have a support portion 13c connected to the bottom portion 13b. In this case, the support portion 13c of the electrode member 13 may be separated from the bottom portion 13b after the magnetic core 11 has been formed and before the bottom portion 13b of the electrode member 13 has been bent.

[0041] The magnetic core 11 may be formed by pressure molding a magnetic powder tablet 15a (15b) while supporting the support portion 13c of the electrode member 13.

[0042] In the above case, the magnetic core 11 may be formed by pressure molding the magnetic powder tablet 15a (15b) while the support portion 13c of the electrode member 13 is supported by the mold 601. [Industrial applicability]

[0043] The inductor according to this disclosure is industrially useful because it can provide an inductor that is less prone to damage to the electrode members even when the electrode members are placed in a mold and the magnetic core is pressure-molded, and has excellent solderability. [Explanation of symbols]

[0044] 11 Magnetic core 12 Coil elements 12a Ends of the coil element (first end, second end) 12c insulation coating 12d conductor 12p coil assembly 13 Electrode Member 13a End section 13b Bottom part 13c Support part 13d recess 13e protrusion 13f plating layer 14 molds 14a Upper punch (mold) 14b Lower punch (mold) 14p Cavity 15a Upper magnetic powder tablet (first magnetic powder tablet) 15b Lower magnetic powder tablet (second magnetic powder tablet) 16 Laser light 501 Inductor 601 mold

Claims

1. A magnetic core containing magnetic material powder and a binder mixed with the magnetic material powder, having a bottom surface and an end surface connected to the bottom surface, A coil element embedded in the magnetic core and having an end protruding from the end face of the magnetic core, An electrode member electrically and mechanically connected to the end of the coil element, Equipped with, The electrode member is bent along the end face and the bottom face of the magnetic core so that it has an end face portion facing the end face of the magnetic core and a bottom face portion facing the bottom face of the magnetic core. The end face portion of the electrode member has an inner surface facing the magnetic core and an outer surface opposite to the inner surface, The outer surface of the end face portion of the electrode member has a recess formed therein that is recessed toward the magnetic core. The end of the coil element is superimposed on the recess of the electrode member and connected to the electrode member. The inner surface of the end face portion of the electrode member is embedded in the magnetic core. The end face of the magnetic core is A first region where the inner surface of the electrode member is provided is connected to the bottom surface of the magnetic core, Two second regions are connected to the bottom surface of the magnetic core and are located on both sides of the first region with the first region in between, It has, An inductor wherein the angle between the bottom surface of the magnetic core and the two second regions of the end surface of the magnetic core is greater than the angle between the bottom surface of the magnetic core and the outer surface of the end surface portion of the electrode member, and less than 90.0°.

2. The inductor according to claim 1, wherein the angle between the outer surface of the end face portion of the electrode member and the two second regions of the end face of the magnetic core is 2.0° or more and 5.0° or less.

3. The inductor according to claim 1 or 2, wherein the inner surface of the end face portion of the electrode member has a convex portion located on the opposite side of the recess and protruding toward the magnetic core.

4. The electrode member further has a plating layer provided on the surface of the electrode member that does not face the magnetic core, The inductor according to claim 1 or 2, wherein the surface of the electrode member facing the magnetic core is not provided with a plating layer.

5. A coil element having a first end and a second end drawn out in opposite directions, A first electrode member having a first end face portion electrically and mechanically connected to the first end of the coil element, and a first bottom portion connected to the first end face portion, A second electrode member having a second end face portion electrically and mechanically connected to the second end of the coil element, and a second bottom portion connected to the second end face portion, The steps include preparing a coil assembly equipped with, A step of preparing a first magnetic powder tablet comprising magnetic material powder and a resin mixed with the magnetic material powder, The steps include placing the first magnetic powder tablet and the coil assembly into the mold, The first magnetic powder tablet and the coil assembly are placed in the mold, and the first magnetic powder tablet is pressure-molded to form a magnetic core. The steps include bending the first bottom portion of the first electrode member and the second bottom portion of the second electrode member, Includes, The magnetic core has a bottom surface, a first end surface connected to the bottom surface, and a second end surface connected to the bottom surface on the opposite side of the first end surface. The first end face of the magnetic core is A first region is provided on the inner surface of the first end face portion of the first electrode member, connected to the bottom surface of the magnetic core, Two second regions are connected to the bottom surface of the magnetic core and are located on both sides of the first region with the first region in between, It has, The second end face of the magnetic core is A third region is provided on the inner surface of the second end face portion of the second electrode member, connected to the bottom surface of the magnetic core, Two fourth regions are located on both sides of the third region, connected to the bottom surface of the magnetic core, with the third region in between. It has, In the step of forming the magnetic core, the first inner wall surface of the mold contacts the outer surface of the first end face portion of the first electrode member and the two second regions of the first end face of the magnetic core, and the second inner wall surface of the mold contacts the outer surface of the second end face portion of the second electrode member and the two fourth regions of the second end face of the magnetic core. The angle between each of the two second regions of the first end face of the magnetic core and the bottom surface of the magnetic core is greater than the angle between the bottom surface of the magnetic core and the outer surface of the first end face portion of the first electrode member, and less than 90.0°, such that in the step of forming the magnetic core, the inclination of the portion of the first inner wall surface of the mold that abuts the outer surface of the first end face portion of the first electrode member is different from the inclination of the portion of the first inner wall surface of the mold that abuts the two second regions of the first end face of the magnetic core. A method for manufacturing an inductor, wherein, in the step of forming the magnetic core, the inclination of the portion of the second inner wall surface of the mold that contacts the outer surface of the second end face portion of the second electrode member is different from the inclination of the portion of the second inner wall surface of the mold that contacts the two fourth regions of the second end face of the magnetic core in the step of forming the magnetic core, such that the angle between each of the two fourth regions of the second end face of the magnetic core and the bottom surface of the magnetic core is greater than the angle between the bottom surface of the magnetic core and the outer surface of the second end face portion of the second electrode member, and less than 90.0°.

6. The step of placing the coil assembly into the mold is, The steps include: deforming the coil assembly so that the distance between the first end face portion of the first electrode member and the second end face portion of the second electrode member is reduced, and then placing it into the mold; Subsequently, with the coil assembly in the mold, the distance between the first end face portion of the first electrode member and the second end face portion of the second electrode member is increased so that the first end face portion and the second end face portion come into contact with the first inner wall surface and the second inner wall surface of the mold, respectively. A method for manufacturing an inductor according to claim 5, including the method described in claim 5.

7. A step of preparing a second magnetic powder tablet containing magnetic material powder and resin, The steps include placing the second magnetic powder tablet into the mold, It further includes, The method for manufacturing an inductor according to claim 5 or 6, wherein the step of forming the magnetic core includes the step of pressurizing the first magnetic powder tablet and the second magnetic powder tablet while the first magnetic powder tablet, the second magnetic powder tablet, and the coil assembly are placed in the mold to form the magnetic core.

8. The step of placing the coil assembly into the mold is performed after the step of placing the first magnetic powder tablet into the mold. The method for manufacturing an inductor according to claim 7, wherein the step of placing the second magnetic powder tablet into the mold is performed after the step of placing the coil assembly into the mold.

9. The step of preparing the coil assembly is, The steps include winding a wire having an insulating coating on its surface in a spiral shape, The steps include forming the coil element by pulling out both ends of the conductor in opposite directions and peeling off the portions of the insulating coating located at both ends of the conductor, A method for manufacturing an inductor according to claim 5 or 6, including the method described in claim 5 or 6.

10. The method for manufacturing an inductor according to claim 5 or 6, wherein the step of preparing the coil assembly includes the step of bending the first end and the second end of the coil element and the first electrode member and the second electrode member.

11. In the step of preparing the coil assembly, the first electrode member further has a first support portion connected to the first bottom portion, In the step of preparing the coil assembly, the second electrode member further has a second support portion connected to the second bottom portion, A method for manufacturing an inductor according to claim 5 or 6, further comprising the step of separating the first support portion and the second support portion of the first electrode member and the second electrode member from the first support portion and the second support portion, respectively, after the step of forming the magnetic core and before the step of bending the first bottom portion of the first electrode member and the second bottom portion of the second electrode member.

12. The method for manufacturing an inductor according to claim 11, wherein the step of forming the magnetic core includes the step of forming the magnetic core by pressurizing the first magnetic powder tablet while supporting the first support portion of the first electrode member and the second support portion of the second electrode member.

13. The method for manufacturing an inductor according to claim 12, wherein the step of forming the magnetic core includes the step of forming the magnetic core by pressurizing the first magnetic powder tablet while the first support portion of the first electrode member and the second support portion of the second electrode member are supported by the mold.

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