Manufacturing method for coil components

Abstract

To miniaturize a coil component while suppressing a damage of a conductive wire.SOLUTION: A manufacturing method of a coil component 100 comprises the steps of: preparing a base body 10; forming a coil part 42 in which a conductive wire 40 is wound to one part of the base body 10; providing an end part 41a of the conductive wire 40 onto an outer surface 20 of the base body 10 by leading out the conductive wire 40 from the coil part 42; and processing the end part 41a of the conductive wire 40 by hooking a predetermined weight toward the outer surface 20 from the end part 41a of the conductive wire 40 by a processing tool 50. The predetermined weight is larger than the maximum weight that the conductive wire 40 is housed in an elastic deformation obtained by a flexural stress of the conductive wire 40, is smaller than the maximum weight that the processing tool 50 and the base body 10 are housed in the elastic deformation, and a deformation amount of the processing tool 50 is larger than the deformation amount of the base body 10 at the time of applying the predetermined weight.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a coil component.

Background Art

[0002] With the increasing sophistication of electronic devices and the like, the number of coil components used in electronic devices has been increasing. Therefore, further miniaturization of coil components is required. As a coil component, there is known a coil component in which a conductor drawn from a coil part is bent and the end of the conductor is drawn out onto the bottom surface of a base body. When the conductor is bent, springback occurs in the conductor, and it is known to perform the bending process in consideration of the springback in advance (for example, Patent Document 1). Further, in order to improve the bending property, it is known to make the thickness of the end of the conductor drawn out on the bottom surface of the base body thinner than the thickness of the conductor in the coil part (for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when a conductor is drawn out from a coil part and the end of the conductor is provided on the first surface of the base body, it is difficult to perform the bending process in consideration of springback as described in Patent Document 1, so the coil component becomes large-sized. Further, when the thickness of a part of the conductor is made thinner as described in Patent Document 2, there is a risk of damaging the conductor.

[0005] The present invention has been made in view of the above problems, and an object thereof is to miniaturize a coil component while suppressing damage to the conductor. [Means for solving the problem]

[0006] The present invention It has a shaft portion and a flange portion provided at one end of the shaft portion. The process of preparing the substrate, The shaft portion The process of forming a coil section around which a conductor is wound, and the process of drawing the conductor out from the coil section. The flange portion is bent and placed on the outer surface of the flange portion. The step of providing the end of the conductor, After the step of providing the end of the conductor, the end of the conductor is sandwiched between the outer surface of the flange and the other part. Machining jig the outer surface of the flange portion Apply a predetermined load toward Press it A method for manufacturing a coil component, comprising the step of processing the end of the conductor, wherein the predetermined load is greater than the maximum load at which the conductor remains elastically deformed, determined from the bending stress of the conductor, and is less than the maximum load at which the processing jig remains elastically deformed and the maximum load at which the base remains elastically deformed, and when the predetermined load is applied, the displacement of the processing jig is greater than the displacement of the base.

[0007] In the above configuration, the end of the conductor and the processing jig after the processing jig has moved away from the end of the conductor. Outer surface of the flange portion The maximum distance between the two can be configured to be smaller than the displacement of the processing jig when the predetermined load is applied.

[0008] In the above configuration, when the predetermined load is applied, the processing jig is at the end of the conductor and Outer surface of the flange portion In contact with, and the end of the conductor and Outer surface of the flange portion The part of the processing jig that is not in contact with the above Outer surface of the flange portion twist The shaft portion side It can be configured to be located in this position.

[0009] In the above configuration, Outer surface of the flange portion A groove is provided in the processing jig, the end of the conductor is positioned inside the groove, and when the predetermined load is applied, the processing jig is in contact with the end of the conductor, and the part of the processing jig that is not in contact with the end of the conductor is in contact with the groove. The shaft portion side It can be configured to be located in this position.

[0010] In the above configuration, Outer surface of the flange portionA depression is provided, and the end portion of the conducting wire is disposed so as to cross the depression. When a load of the predetermined load is applied, the processing jig contacts the end portion of the conducting wire, and a part of the processing jig that does not contact the end portion of the conducting wire is located The shaft portion side outside the depression.

[0011] In the above configuration, In the step of providing the end of the conductor, a lead wire formed of the conducting wire connecting the end portion of the conducting wire and the coil portion is Outer surface of the flange portion adjacent to Outer peripheral surface of the flange portion and disposed outside On the outer surface of the flange portion the end portion of the conducting wire is provided, In the process of processing the end of the aforementioned conductor, at a position away from the processing jig A part of the aforementioned leader line compared with before the load of the predetermined load is applied Outer peripheral surface of the flange portion and moves away from The end of the conductor is processed in this manner. This can be the configuration.

[0012] In the above configuration, the end portion of the conducting wire in the processing jig and Outer surface of the flange portion the portion contacting

[0013] can be configured to be formed of urethane rubber or silicone rubber. The process In the above configuration, after processing the end portion of the conducting wire, a step of joining a solder film to the end portion of the conducting wire to form an external electrode including the end portion of the conducting wire and the solder film can be provided.

[0014] In the above configuration, the base body can be a drum core having a shaft portion and a flange portion.

Advantages of the Invention

[0015] According to the present invention, while suppressing damage to the conducting wire, the coil component can be miniaturized.

Brief Description of the Drawings

[0016] [Figure 1] FIGS. 1(a) to 1(e) are side views showing a manufacturing method when the coil component according to the embodiment is viewed from the X side. [Figure 2] Figs. 2(a) to 2(e) are side views showing the manufacturing method of the coil component according to the embodiment when viewed from the -Y side. [Figure 3] Fig. 3(a) is a cross-sectional view showing one step of manufacturing the coil component according to the embodiment, and Fig. 3(b) is a cross-sectional view showing one step of manufacturing the coil component according to the first modification. [Figure 4] Figs. 4(a) to 4(f) are side views showing the manufacturing method of the coil component according to the second modification. [Figure 5] Figs. 5(a) to 5(f) are side views showing the manufacturing method of the coil component according to the third modification. [Figure 6] Figs. 6(a) to 6(c) are diagrams showing the method of evaluating the stress-strain characteristics of the processing jig, the conducting wire, and the flange portion. [Figure 7] Fig. 7 is an evaluation result showing the relationship between stress and strain in the flange portion, the conducting wire, and the processing jig.

Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described with appropriate reference to the drawings. However, the present invention is not limited to the illustrated aspects. Also, the same reference numerals are assigned to common components in the plurality of drawings. Note that each drawing is not necessarily drawn to an exact scale for convenience of explanation.

[0018] [Embodiment] Figures 1(a) to 1(e) are side views showing the manufacturing method of the coil component according to the embodiment, viewed from the +X side. Figures 2(a) to 2(e) are side views showing the manufacturing method of the coil component according to the embodiment, viewed from the -Y side. The X, Y, and Z axes are orthogonal to each other. In this embodiment, a drum core is shown as an example of the base body 10, but other cases are also possible, such as a T-core having a flange on only one side. In Figures 1(a) to 1(e) and Figures 2(a) to 2(e), hatching is applied to the components for clarity (the same applies to similar figures below). Also, in Figures 1(a) to 1(e) and Figures 2(a) to 2(e), the coil portion 42 is shown by viewing through the outer casing 70, and the shaft portion 12 is shown by viewing through the outer casing 70 and the coil portion 42. In Figures 1(c) and 2(c), the metal films 30a and 30b and the ends 41a and 41b of the conductor 40 are shown through the processing jig 50, and in Figures 1(e) and 2(e), the ends 41a and 41b of the conductor 40 incorporated into a portion of the external electrodes 60a and 60b are shown. The coil component may be a power inductor incorporated into a power line, an inductor used in a signal line, or something else.

[0019] As shown in Figures 1(a) and 2(a), a drum core base 10 is prepared, which has a shaft portion 12 extending in the Z-axis direction, one flange portion 14 provided at the +Z end of the shaft portion 12, and the other flange portion 16 provided at the -Z end of the shaft portion 12. In the following description, the focus will be on the flange portion 14 on the side closer to the substrate when mounted on a substrate. The outer shape of the flange portion 14 is, for example, approximately the same size as the outer shape of the other flange portion 16, but it may be larger or smaller than the outer shape of the other flange portion 16. The thickness of the flange portion 14 may be the same as the thickness of the other flange portion 16, or it may be a different thickness. The flange portion 14 has an inner surface 18 on the side of the shaft portion 12 and an outer surface 20 on the opposite side of the shaft portion 12.

[0020] The substrate 10 is formed by, for example, filling a mold cavity with a paste made by mixing magnetic powder and resin and press molding it to form a molded body, and then performing a heat treatment on this molded body at, for example, 200°C to solidify the resin. The magnetic powder can be, for example, ferrite magnetic powder or metallic magnetic powder. Examples of ferrite magnetic powder include ferrite materials such as Ni-Zn or Mn-Zn. Examples of metallic magnetic powder include soft magnetic alloy materials such as Fe-Si-Cr, Fe-Si-Al, or Fe-Si-Cr-Al, magnetic metal materials such as Fe or Ni, amorphous magnetic metal materials, or nanocrystalline magnetic metal materials. The resin can be, for example, a resin with excellent insulating properties such as polyvinyl butyral (PVB) resin or epoxy resin.

[0021] The base body 10 may be formed by processing a large block of molded material to create a molded body having a shaft portion 12 and flange portions 14 and 16, and then heat-treating this molded body. The heat treatment may be performed before processing the molded body having the shaft portion 12 and flange portions 14 and 16. Furthermore, the base body 10 is not limited to being formed by solidifying magnetic powder with resin, but may also be formed by bonding magnetic powders together with inorganic material. In this case, the base body 10 is formed by heat-treating a molded body formed by press-molding magnetic powder at, for example, 600°C to 1100°C. Also, the base body 10 is not limited to being a magnetic material, but may be a non-magnetic material formed from aluminum oxide (alumina) or silicon oxide (glass), etc.

[0022] The shaft portion 12 has, for example, a roughly rectangular cross-sectional shape parallel to the XY plane with rounded corners. The flange portions 14 and 16 have, for example, a roughly rectangular cross-sectional shape parallel to the XY plane and are plate-like with thickness in the Z-axis direction. The shaft portion 12 may have a circular, elliptical, roughly rectangular, polygonal shape with pentagons or more, or a combination thereof in cross-sectional shape. The shaft portion 12 is smaller than the outer shape of the flange portions 14 and 16 when viewed in the Z-axis direction and is located near the center of the flange portions 14 and 16. The length dimensions of the base body 10 in the X-axis direction, the Y-axis direction, and the Z-axis direction are set appropriately as needed.

[0023] After preparing the substrate 10, metal films 30a and 30b are formed on the outer surface 20 of the flange portion 14. The metal films 30a and 30b extend between the opposing outer surfaces 22 and 24 of the flange portion 14 and are provided substantially parallel to each other. The metal films 30a and 30b are formed, for example, by forming a base layer of copper (Cu) or silver (Ag) by sputtering or applying a conductive paste, and then forming a plating layer of nickel (Ni) and tin (Sn) on the base layer using a plating method. Note that the metal films 30a and 30b are not limited to multiple layers with a plating layer formed on the base layer, but may also be a single layer consisting only of the base layer. Furthermore, the metal films 30a and 30b may have an adhesion layer of titanium (Ti) or chromium (Cr) for adhesion to the flange portion 14. The thickness of the metal films 30a and 30b is, for example, about 1 μm to 50 μm.

[0024] After forming the metal films 30a and 30b, the conductor 40 is wound around the shaft portion 12 of the base body 10 to form a coil portion 42 made of the conductor 40. After pulling the conductor 40 outwards from each of the pair of ends of the coil portion 42 beyond the outer peripheral surface 22 of the flange portion 14, the conductor 40 is bent so that the ends 41a and 41b of the conductor 40 are positioned on the metal films 30a and 30b and brought out onto the outer surface 20 of the flange portion 14. Here, the portion of the conductor 40 that connects the ends 41a and 41b to the coil portion 42 is called the lead wire 44. In addition, the portion of the lead wire 44 that is bent to bring out the ends 41a and 41b of the conductor 40 onto the outer surface 20 of the flange portion 14 is called the bent portion 48. The lead wires 44 are connected to the ends 41a and 41b of the conductor wire 40, respectively, and the bent portion 48 is located near the outer surface 22 of the flange portion 14. Even when the conductor wire 40 is bent at the bent portion 48 so that the ends 41a and 41b of the conductor wire 40 are bent along the outer surface 20 of the flange portion 14, the ends 41a and 41b of the conductor wire 40 are formed to move away from the outer surface 20 of the flange portion 14 as they move from the bent portion 48 towards the tips 43a and 43b due to springback.

[0025] The coil portion 42 only needs to have the conductor 40 wound around the shaft portion 12 at least once, and may be wound in only one layer around the shaft portion 12, or in part or all of the coil portion to be wound in multiple layers. The coil portion 42 may also be formed by a so-called alpha winding, in which the central part of the conductor 40 is wound first, and then the winding continues toward both ends of the conductor 40.

[0026] The conductor 40 is a metal wire, for example, made of copper (Cu) or silver (Ag), whose outer surface is covered with an insulating coating made of urethane. The insulating coating may be made of an insulating material other than urethane, such as a resin material like polyimide, polyamide-imide, or polyester. The cross-sectional shape of the metal wire is, for example, circular, but it may also be rectangular.

[0027] After forming the coil portion 42, an outer casing 70 covering the coil portion 42 may be formed. The outer casing 70 is formed by applying a resin material, for example, by brushing, roller transfer, or dispensing, and then curing the resin material. The resin component of the resin material is preferably a thermosetting resin with excellent insulating properties, such as epoxy resin or polyimide resin. The resin material may also contain magnetic material fillers, such as magnetic particles with an average particle size of 10 μm or less. For example, the resin material may be formed by mixing a magnetic material and a resin; for example, ferrite may be used as the magnetic material and epoxy resin as the resin component. Furthermore, the resin material may contain non-magnetic material fillers such as silica particles, or it may contain a combination or mixture of magnetic and non-magnetic materials.

[0028] As shown in Figures 1(b) and 2(b), the machining jig 50 is positioned above the outer surface 20 of the flange portion 14. The machining jig 50 is made of an elastic material, and is made of a material with a Young's modulus smaller than that of the base body 10. For example, the machining jig 50 is made of urethane rubber or silicone rubber.

[0029] As shown in Figures 1(c) and 2(c), the processing jig 50 is pressed against the outer surface 20 of the flange portion 14 by sandwiching the ends 41a and 41b of the conductor wire 40 between the processing jig 50 and the outer surface 20 of the flange portion 14. By pressing the processing jig 50 against the outer surface 20 of the flange portion 14, the thickness of the processing jig 50 becomes a thickness T2 that is thinner than the original thickness T1. This difference in thickness (T1-T2) is the amount of displacement that occurs in the processing jig 50 when it is pressed against the outer surface 20 of the flange portion 14. By pressing the processing jig 50 against the outer surface 20 of the flange portion 14, the ends 41a and 41b of the conductor wire 40 deform to be parallel to the outer surface 20 of the flange portion 14 and are pressed against the metal films 30a and 30b.

[0030] Here, we will explain the load when the processing jig 50 is pressed against the outer surface 20 of the flange portion 14. As shown in Figures 1(b), 1(c), 2(b), and 2(c), when the processing jig 50 is pressed against the outer surface 20 of the flange portion 14, the ends 41a and 41b of the conductor wire 40 deform so that they bend with the bent portion 48 as the fulcrum. Therefore, when the processing jig 50 is pressed against the outer surface 20 of the flange portion 14, bending stress is applied to the conductor wire 40. The bending stress can be found by dividing the bending moment by the section modulus. The bending moment can be found from the length of the object in which bending occurs and the load applied to the object. The section modulus can be found using a predetermined formula; for example, if the cross-section is circular, it can be found by multiplying the square of the diameter by pi (π) and dividing the result by 32. In this embodiment, the bending moment can be determined from the length L of the ends 41a and 41b of the conductor 40 (see Figure 1(b)) and the load applied to the ends 41a and 41b of the conductor 40. The section modulus can be determined from the cross-section of the ends 41a and 41b of the conductor 40 using a formula.

[0031] Furthermore, when the processing jig 50 is pressed against the outer surface 20 of the flange portion 14, compressive stress is applied to both the processing jig 50 and the flange portion 14. The compressive stress on the processing jig 50 can be determined by dividing the load applied when the processing jig 50 is pressed against the outer surface 20 of the flange portion 14 by the area in contact between the processing jig 50 and the outer surface 20 of the flange portion 14 and the ends 41a and 41b of the conductor 40. Similarly, the compressive stress on the flange portion 14 can be determined by dividing the load applied to the outer surface 20 of the flange portion 14 when the processing jig 50 is pressed against the outer surface 20 of the flange portion 14 by the area in contact between the outer surface 20 of the flange portion 14 and the ends 41a and 41b of the conductor 40.

[0032] The load applied when pressing the processing jig 50 against the outer surface 20 of the flange portion 14 is greater than the maximum load at which the wire 40 remains elastically deformed, as determined from the bending stress of the wire 40, and less than the maximum load at which both the processing jig 50 and the flange portion 14 remain elastically deformed. In the following, such a load will be referred to as the predetermined load. By pressing the processing jig 50 against the outer surface 20 of the flange portion 14 with a load greater than the maximum load at which the wire 40 remains elastically deformed, as determined from the bending stress of the wire 40, the bent portion 48 deforms so that it bulges outward, as shown in Figure 1(c). Furthermore, since the processing jig 50 is made of a material with a lower Young's modulus than the base body 10, when the predetermined load is applied to the processing jig 50, the displacement of the processing jig 50 is greater than the displacement of the flange portion 14.

[0033] As shown in Figures 1(d) and 2(d), the processing jig 50 is moved away from the outer surface 20 of the flange portion 14. As described above, by pressing the processing jig 50 against the outer surface 20 of the flange portion 14 with a predetermined load, the bent portion 48 deforms so that it bulges outward. This deformation reduces the residual stress at the ends 41a and 41b of the conductor wire 40, and the amount of springback at the ends 41a and 41b of the conductor wire 40 is reduced, resulting in a smaller gap between them and the outer surface 20 of the flange portion 14 compared to before the processing jig 50 was pressed. If the maximum distance between the ends 41a and 41b of the conductor wire 40 and the outer surface 20 of the flange portion 14 before pressing the processing jig 50 is H1 (see Figure 1(a)), and the maximum distance after pressing is H2 (see Figure 1(d)), then the maximum distance H2 is smaller than the maximum distance H1. Furthermore, the maximum distance H2 is smaller than the displacement (T1-T2) of the machining jig 50 when it is pressed against the outer surface 20 of the flange portion 14 with a predetermined load.

[0034] Furthermore, by making the load applied when pressing the processing jig 50 against the outer surface 20 of the flange portion 14 smaller than the maximum load at which the processing jig 50 and the flange portion 14 remain within elastic deformation limits, the processing jig 50 and the flange portion 14 return to their state before the processing jig 50 was pressed against them after the processing jig 50 is removed from the outer surface 20 of the flange portion 14.

[0035] As shown in Figures 1(e) and 2(e), solder films 62a and 62b are applied to the surfaces of the metal films 30a and 30b, for example by dispensing or transferring. The solder films 62a and 62b are, for example, tin-silver solder or tin-silver-copper solder and contain flux components. Subsequently, the solder films 62a and 62b are heated to a temperature above their melting point, for example, 220°C or higher, to melt them. The flux components contained in the solder films 62a and 62b peel off the insulating coating at the ends 41a and 41b of the conductor wire 40, exposing the metal wire at the ends 41a and 41b of the conductor wire 40. As a result, the end 41a of the conductor wire 40, the metal film 30a, and the solder film 62a are joined together, forming an external electrode 60a that is electrically connected to the coil portion 42. Similarly, the end 41b of the conductor 40, the metal film 30b, and the solder film 62b are joined together to form an external electrode 60b that is electrically connected to the coil portion 42. Thus, the coil component 100 according to the embodiment is formed.

[0036] As described above, according to this embodiment, as shown in Figures 1(a) and 2(a), the conductor 40 is drawn out from the coil portion 42, and the ends 41a and 41b of the conductor 40 are provided on the outer surface 20 of the flange portion 14. As shown in Figures 1(c) and 2(c), the ends 41a and 41b of the conductor 40 are processed between the processing jig 50 and the outer surface 20 of the flange portion 14 by applying a predetermined load toward the outer surface 20 of the flange portion 14 using the processing jig 50. At this time, the predetermined load applied to press the processing jig 50 against the outer surface 20 of the flange portion 14 is greater than the maximum load at which the conductor 40 remains elastically deformed, which can be determined from the bending stress of the conductor 40, and is smaller than the maximum load at which the processing jig 50 remains elastically deformed and the maximum load at which the flange portion 14 remains elastically deformed. By applying a load greater than the maximum load at which the conductor 40 remains elastically deformed, determined from the bending stress of the conductor 40, the amount of springback that occurs at the ends 41a and 41b of the conductor 40 after the processing jig 50 has moved away from the outer surface 20 of the flange 14 can be reduced, bringing the ends 41a and 41b of the conductor 40 closer to the outer surface 20 of the flange 14. Therefore, the coil component 100 can be miniaturized. By applying a load smaller than the maximum load at which the processing jig 50 and the flange 14 remain elastically deformed, plastic deformation of the processing jig 50 and the flange 14 is suppressed, and the processing jig 50 can be used repeatedly. Furthermore, when a predetermined load is applied to the processing jig 50, the displacement of the processing jig 50 is greater than the displacement of the flange 14. By processing the ends 41a and 41b of the conductor wire 40 using such a flexible processing jig 50, damage to the ends 41a and 41b of the conductor wire 40 can be suppressed.

[0037] Furthermore, the predetermined load applied to press the processing jig 50 against the outer surface 20 of the flange portion 14 may be at least twice, three times, or even four times the maximum load at which the wire 40 remains within its elastic deformation, as determined by the bending stress of the wire 40, in order to suppress the springback of the wire 40. In addition, in order to use a soft processing jig 50 that minimizes damage to the wire 40, when the predetermined load is applied to the processing jig 50, the displacement of the processing jig 50 is preferably at least twice, more preferably three times, and even more preferably four times, the displacement of the flange portion 14. For example, the Young's modulus of the processing jig 50 is preferably 1 / 10 or less, more preferably 1 / 100 or less, and even more preferably 1 / 1000 or less, of the Young's modulus of the flange portion 14.

[0038] Furthermore, in this embodiment, the maximum distance H2 between the ends 41a and 41b of the conductor 40 and the outer surface 20 of the flange portion 14 after the processing jig 50 has moved away from the ends 41a and 41b of the conductor 40 is smaller than the displacement (T1-T2) of the processing jig 50 when a predetermined load is applied to it. As a result, the ends 41a and 41b of the conductor 40 come closer to the outer surface 20 of the flange portion 14, making it possible to miniaturize the coil component 100.

[0039] Thus, the predetermined load applied when pressing the processing jig 50 against the outer surface 20 of the flange portion 14 is a load that reduces the amount of springback of the ends 41a and 41b of the conductor wire 40 after the processing jig 50 has left the outer surface 20 of the flange portion 14. For example, the load is such that the maximum distance H2 between the ends 41a and 41b of the conductor wire 40 and the outer surface 20 of the flange portion 14 after the processing jig 50 has left the outer surface 20 of the flange portion 14 is smaller than the thickness of the conductor wire 40, preferably less than or equal to 3 / 4 of the thickness of the conductor wire 40, and more preferably less than or equal to 1 / 2 of the thickness.

[0040] Furthermore, in this embodiment, as shown in Figure 1(c), a portion of the lead wire 44 connecting the ends 41a and 41b of the conductor wire 40 to the coil portion 42, for example, the bent portion 48, is located away from the processing jig 50 when a predetermined load is applied to the processing jig 50, and is further away from the outer surface 22 of the flange portion 14 compared to before the predetermined load was applied. As a result, the residual stress at the ends 41a and 41b of the conductor wire 40 is reduced, and the amount of springback at the ends 41a and 41b of the conductor wire 40 can be reduced after the processing jig 50 has moved away from the outer surface 20 of the flange portion 14.

[0041] Furthermore, in this embodiment, the processing jig 50 is made of urethane rubber or silicone rubber. This reduces the amount of springback of the ends 41a and 41b of the conductor 40 while suppressing damage to the ends 41a and 41b of the conductor 40. Note that the processing jig 50 is not limited to being made entirely of urethane rubber or silicone rubber; it is sufficient if at least the parts that contact the ends 41a and 41b of the conductor 40 and the outer surface 20 of the flange portion 14 are made of urethane rubber or silicone rubber.

[0042] Furthermore, in this embodiment, as shown in Figures 1(e) and 2(e), after processing the ends 41a and 41b of the conductor 40 with the processing jig 50, solder films 62a and 62b are joined to the ends 41a and 41b of the conductor 40 to form the external electrodes 60a and 60b. As a result, the solder films 62a and 62 are joined to the ends 41a and 41b of the conductor 40 that are close to the outer surface 20 of the flange portion 14, making it possible to miniaturize the coil component 100.

[0043] Furthermore, in this embodiment, the base body 10 is a drum core having a shaft portion 12 and a flange portion 14. With such a structure, it becomes easier to press the processing jig 50 with a large load toward the outer surface 20 of the flange portion 14, thus facilitating the processing of the ends 41a and 41b of the conductor wire 40.

[0044] Furthermore, in this embodiment, the outer casing 70 is formed to cover the coil portion 42. As a result, the conductor 40 is fixed by the outer casing 70, so when the ends 41a and 41b of the conductor 40 are processed by the processing jig 50, the load applied to the processing jig 50 is efficiently applied to the ends 41a and 41b of the conductor 40.

[0045] [First variation] Figure 3(a) is a cross-sectional view showing one step in the manufacturing process of a coil component according to the embodiment, and Figure 3(b) is a cross-sectional view showing one step in the manufacturing process of a coil component according to the first modified example. As shown in Figure 3(a), in the above embodiment, an example is shown in which the processing jig 50 is pressed against the outer surface 20 of the flange portion 14 to such an extent that the surface 52 of the processing jig 50 on the flange portion 14 side substantially coincides with the outer surface 20 of the flange portion 14. However, the method is not limited to this case, and as shown in Figure 3(b), the processing jig 50 may also be pressed against the outer surface 20 of the flange portion 14 such that the portion of the surface 52 of the processing jig 50 on the flange portion 14 side that is located outside the outer surface 20 of the flange portion 14 is pushed toward the shaft portion 12 side than the outer surface 20 of the flange portion 14. If the distance between the part of the machining jig 50 located closest to the shaft portion 12 and the outer surface 20 of the flange portion 14 is defined as the amount of indentation D of the machining jig 50, then in the first modified example, the amount of indentation D is greater than 0. In the above embodiment, however, the amount of indentation D is approximately 0. Furthermore, when the amount of indentation D is greater than 0, as in the first modified example, the displacement of the machining jig 50 when it is pressed against the outer surface 20 of the flange portion 14 is the original thickness T1 of the machining jig 50 (see Figure 1(b)) minus the thickness T2 of the machining jig 50 on the outer surface 20 when it is pressed against the outer surface 20 of the flange portion 14 (T1-T2).

[0046] As shown in Figure 3(b), when a predetermined load is applied to the processing jig 50, the processing jig 50 is in contact with the ends 41a, 41b of the conductor wire 40 and the outer surface 20 of the flange portion 14. At the same time, a portion of the processing jig 50 that is not in contact with the ends 41a, 41b of the conductor wire 40 and the outer surface 20 of the flange portion 14 may be located on the shaft portion 12 side of the outer surface 20 of the flange portion 14. This reduces the air gap around the ends 41a, 41b of the conductor wire 40, and the ends 41a, 41b of the conductor wire 40 are sufficiently held and pressed by the processing jig 50, thereby reducing the amount of springback of the ends 41a, 41b of the conductor wire 40. As a result, the coil component 100 can be made smaller.

[0047] [Second variation] Figures 4(a) to 4(f) are side views showing a method for manufacturing a coil component according to a second modified example. Figures 4(a) to 4(c) are side views viewed from the +X side, and Figures 4(d) to 4(f) are side views viewed from the -Y side. As shown in Figures 4(a) and 4(d), in the second modified example, two grooves 32a and 32b are provided on the outer surface 20 of the flange portion 14. The grooves 32a and 32b extend substantially parallel to each other and open to opposing outer surfaces 22 and 24 of the flange portion 14. Metal films 30a and 30b are formed on the inner surfaces of the grooves 32a and 32b. The ends 41a and 41b of the conductor wire 40 are drawn into the grooves 32a and 32b and positioned on the metal films 30a and 30b. Even in this case, springback occurs at the ends 41a and 41b of the conductor 40, and the ends 41a and 41b of the conductor 40 are formed to move away from the bottom surface of the grooves 32a and 32b as they move from the bent portion 48 towards the tip 43a and 43b. The rest is the same as in Figures 1(a) and 2(a), so the explanation is omitted.

[0048] As shown in Figures 4(b) and 4(e), the processing jig 50 is pressed against the outer surface 20 of the flange portion 14 with a predetermined load, with the ends 41a and 41b of the conductor wire 40 sandwiched between the processing jig 50 and the bottom surfaces of the grooves 32a and 32b. At this time, the processing jig 50 is pressed against the outer surface 20 of the flange portion 14 so that a part of the processing jig 50 enters into the grooves 32a and 32b, and the ends 41a and 41b of the conductor wire 40 are pressed against the metal films 30a and 30b by the processing jig 50. In this case, the part of the processing jig 50 that is located outside the outer surface 20 of the flange portion 14 is located on the shaft portion 12 side of the bottom surfaces of the grooves 32a and 32b. The predetermined load applied to the processing jig 50 is, as in the above embodiment, greater than the maximum load at which the conductor 40 remains elastically deformed, determined from the bending stress of the conductor 40, and less than the maximum load at which the processing jig 50 and the flange portion 14 remain elastically deformed. As a result, the bent portion 48 deforms so that it bulges outward.

[0049] As shown in Figures 4(c) and 4(f), the processing jig 50 is moved away from the outer surface 20 of the flange portion 14. As in the above embodiment, the bent portion 48 is deformed to bulge outward, so the residual stress at the ends 41a and 41b of the conductor wire 40 is reduced. Therefore, the amount of springback at the ends 41a and 41b of the conductor wire 40 is reduced, and the gap between them and the bottom surfaces of the grooves 32a and 32b becomes smaller compared to before the processing jig 50 was pressed against them.

[0050] Subsequently, solder films 62a and 62b are applied to the grooves 32a and 32b and melted to form the external electrodes 60a and 60b. This process is the same as in the above embodiment, so it is not illustrated or described.

[0051] In the second modified example, when a predetermined load is applied to the machining jig 50, the machining jig 50 is in contact with the ends 41a and 41b of the wire 40, and the portion of the machining jig 50 that is not in contact with the ends 41a and 41b of the wire 40 is located on the shaft portion 12 side of the grooves 32a and 32b. This reduces the amount of springback of the ends 41a and 41b of the wire 40 when they are positioned inside the grooves 32a and 32b, and brings the ends 41a and 41b of the wire 40 closer to the bottom surface of the grooves 32a and 32b.

[0052] [Third variation] Figures 5(a) to 5(f) are side views showing a method for manufacturing a coil component according to a third modified example. Figures 5(a) to 5(c) are side views viewed from the +X side, and Figures 5(d) to 5(f) are side views viewed from the -Y side. As shown in Figures 5(a) and 5(d), in the third modified example, a recess 34 is provided on the outer surface 20 of the flange portion 14. The recess 34 is located on the inside of the outer surface 20 of the flange portion 14 and does not open to the outer circumferential surface. Metal films 30a and 30b are formed on the outer surface 20 of the flange portion 14 so as to cross the recess 34. That is, metal films 30a and 30b are also formed on a part of the inner surface of the recess 34. The ends 41a and 41b of the conductor wire 40 are pulled out onto the outer surface 20 of the flange portion 14 so as to cross the recess 34 and are located on the metal films 30a and 30b. Even in this case, springback occurs at the ends 41a and 41b of the conductor 40, and the ends 41a and 41b of the conductor 40 are formed to move away from the outer surface 20 of the flange 14 as they move from the bent portion 48 towards the tip 43a and 43b. The rest is the same as in Figures 1(a) and 2(a), so the explanation is omitted.

[0053] As shown in Figures 5(b) and 5(e), the ends 41a and 41b of the conductor wire 40 are sandwiched between the processing jig 50 and the outer surface 20 of the flange portion 14, and the processing jig 50 is pressed against the outer surface 20 of the flange portion 14 with a predetermined load. At this time, the processing jig 50 is pressed against the outer surface 20 of the flange portion 14 so that a part of the processing jig 50 enters the recess 34, and a part of the ends 41a and 41b of the conductor wire 40 are pressed against the metal films 30a and 30b formed on the inner surface of the recess 34. In this case, the part of the processing jig 50 that is located outside the outer surface 20 of the flange portion 14 is located on the shaft portion 12 side of the bottom surface of the recess 34. The predetermined load applied to the processing jig 50 is, as in the above embodiment, greater than the maximum load at which the conductor 40 remains elastically deformed, determined from the bending stress of the conductor 40, and less than the maximum load at which the processing jig 50 and the flange portion 14 remain elastically deformed. As a result, the bent portion 48 deforms so that it bulges outward.

[0054] As shown in Figures 5(c) and 5(f), the processing jig 50 is moved away from the outer surface 20 of the flange portion 14. As in the above embodiment, the bent portion 48 is deformed to bulge outward, so the residual stress at the ends 41a and 41b of the conductor wire 40 is reduced. Therefore, the springback amount of the ends 41a and 41b of the conductor wire 40 is reduced, and they are processed to bend along the recess 34, so that the gap between them and the outer surface 20 of the flange portion 14 is smaller than before the processing jig 50 was pressed against them.

[0055] Subsequently, solder films 62a and 62b are applied to the metal films 30a and 30b and melted to form the external electrodes 60a and 60b. This is the same as in the above embodiment, so it is not shown or described.

[0056] In the third modified example, when a predetermined load is applied to the processing jig 50, the processing jig 50 is in contact with the ends 41a and 41b of the conductor wire 40, and a portion of the processing jig 50 that is not in contact with the ends 41a and 41b of the conductor wire 40 is located on the shaft portion 12 side of the recess 34. This reduces the amount of springback of the ends 41a and 41b of the conductor wire 40 when they are positioned to cross the recess 34, and allows the ends 41a and 41b of the conductor wire 40 to bend along the recess 34 during processing.

[0057] In addition, in the above embodiment and its modified form, multiple coil components may be arranged side by side, and the ends 41a and 41b of the conductors 40 in multiple coil components may be processed together using one large processing jig 50. In this case, even if the processing jig 50 deforms due to stress, the processing jig 50 can be stably brought into contact with the outer surfaces 20 of the flange portions 14 of the multiple coil components. Furthermore, in the above embodiment and its modified form, the ends 41a and 41b of the conductors 40 may be processed by repeatedly pressing the processing jig 50 against the outer surfaces 20 of the flange portions 14.

[0058] In the above embodiment and its modifications, a coil component in which a conductor 40 is wound around the surface of a drum core substrate 10 to form a coil portion 42 was shown as an example. However, any coil component such as a coil component in which the coil portion 42 is built into the substrate 10, or a coil component made of winding, lamination, thin film, etc., may be used. [Examples]

[0059] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the embodiments described in these examples.

[0060] [Example 1] In Example 1, a base body 10 without grooves and depressions on the outer surface 20 of the flange portion 14 was used, as shown in Figures 1(a) to 1(e) and Figures 2(a) to 2(e). The base body 10 was formed using a paste mixed with ferrite magnetic powder and epoxy resin. The conductor 40 was a copper metal wire covered with an insulating coating and had a diameter of 0.18 mm. The processing jig 50 was made of urethane rubber with a shear of A50. When the ends 41a and 41b of the conductor 40 were pulled out to the outer surface 20 of the flange portion 14, the maximum distance H1 (see Figure 1(a)) between the ends 41a and 41b and the outer surface 20 of the flange portion 14 was greater than the diameter of the conductor 40. The ends 41a and 41b of the conductor wire 40 were processed by pressing the processing jig 50 against the outer surface 20 of the flange portion 14 with the ends 41a and 41b of the conductor wire 40 sandwiched between them. In this processing, the load applied from above the processing jig 50 was set to 20N, and the amount of indentation D (see Figure 5(b)) when pressing the processing jig 50 against the outer surface 20 of the flange portion 14 was set to 1.5mm. This load is greater than the maximum load at which the conductor wire 40 remains within elastic deformation, as determined from the bending stress of the conductor wire 40, and less than the maximum load at which the processing jig 50 and the flange portion 14 remain within elastic deformation.

[0061] [Example 2] In Example 2, a base body 10 was used in which grooves 32a and 32b were provided on the outer surface 20 of the flange portion 14, as shown in Figures 4(a) to 4(f). The depth of the grooves 32a and 32b was 0.5 mm. The amount of indentation D when pressing the processing jig 50 against the outer surface 20 of the flange portion 14 was set to 1.8 mm. Other aspects were the same as in Example 1.

[0062] [Example 3] In Example 3, a base body 10 was used in which a recess 34 was provided on the outer surface 20 of the flange portion 14, as shown in Figures 5(a) to 5(f). The depth of the recess 34 was 0.5 mm. The amount of indentation D when pressing the processing jig 50 against the outer surface 20 of the flange portion 14 was set to 2.1 mm. Other aspects were the same as in Example 1.

[0063] In Examples 1 to 3, the maximum distance H2 (see Figure 1(d)) between the ends 41a and 41b of the conductor 40 and the outer surface 20 of the flange portion 14 after processing the ends 41a and 41b of the conductor 40 using the processing jig 50 was 0.1 mm or less, which is smaller than the diameter of the conductor 40. In this way, by processing the ends 41a and 41b of the conductor 40 using the processing jig 50, the amount of springback of the ends 41a and 41b of the conductor 40 can be reduced, and the ends 41a and 41b of the conductor 40 can be brought closer to the outer surface 20 of the flange portion 14.

[0064] Next, we will explain the results of evaluating the stress-strain characteristics showing the relationship between stress and strain for the flange 14, the conductor 40, and the processing jig 50. Figures 6(a) to 6(c) show the methods used to evaluate the stress-strain characteristics of the processing jig 50, the conductor 40, and the flange 14. As shown in Figure 6(a), for the processing jig 50, the relationship between compressive stress and strain was evaluated when a load A was applied from above and the load A was increased. As shown in Figure 6(b), for the conductor 40, the relationship between bending stress and strain was evaluated when a load B was applied near the tip 43a and the load B was increased. As shown in Figure 6(c), for the flange 14, the relationship between compressive stress and strain was evaluated when a load C was applied to the outer surface 20 and the load C was increased. The evaluation was conducted for the case where the flange portion 14 is formed using a paste mixed with ferrite magnetic powder and epoxy resin, the conductor 40 is a metal wire made of copper, and the processing jig 50 is made of urethane rubber.

[0065] Figure 7 shows the evaluation results illustrating the relationship between stress and strain in the flange 14, the conductor wire 40, and the processing jig 50. In Figure 7, the stress-strain curves for the conductor wire 40 and the processing jig 50 are shown up to the yield point where elastic deformation is achieved, while the stress-strain curve for the flange 14 is shown when measured within the range of stress required for processing. As shown in Figure 7, the bending stress at which the conductor wire 40 settles with elastic deformation is sufficiently smaller than the compressive stress at which the flange 14 and the processing jig 50 settle with elastic deformation. That is, the bending yield stress, which is the yield point of the bending stress generated in the conductor wire 40 when it is bent, is sufficiently smaller than the compressive yield stress, which is the yield point of the compressive stress generated when the flange 14 and the processing jig 50 are pressed. For example, the bending yield stress of the conductor wire 40 is less than 1 / 5 of the compressive yield stress of the flange 14 and the processing jig 50.

[0066] From this, it can be confirmed that the load applied when pressing the processing jig 50 against the outer surface 20 of the flange portion 14 can be set to be greater than the maximum load at which the wire 40 remains within its elastic deformation range, as determined from the bending stress of the wire 40, and less than the maximum load at which the processing jig 50 and the flange portion 14 remain within their elastic deformation range.

[0067] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of Symbols]

[0068] 10 Base 12 Shaft section 14, 16 Guard section 18. Inner self 20 Exterior 22, 24 Outer surface 30a, 30b metal film 32a, 32b groove 34. Indentation 40 Conductor 41a, 41b end 42 Coil section 43a, 43b tip 44 Lead-out line 48 Folding section 50 Machining jigs 52 sides 60a External electrode 62a Solder film 100 coil components

Claims

1. A step of preparing a base having a shaft portion and a flange portion provided at one end of the shaft portion, The process of forming a coil portion around which a conductor is wound on the shaft portion, The process involves drawing the conductor from the coil portion and bending it at the flange portion, thereby providing the end of the conductor on the outer surface of the flange portion. The process includes the step of providing the end of the conductor, followed by the step of pressing a processing jig against the outer surface of the flange with a predetermined load applied, so as to sandwich the end of the conductor between the jig and the outer surface of the flange, thereby processing the end of the conductor. The predetermined load is greater than the maximum load at which the conductor remains elastically deformed, determined from the bending stress of the conductor, and less than the maximum load at which the processing jig remains elastically deformed and the maximum load at which the base remains elastically deformed. A method for manufacturing a coil component, wherein, when the predetermined load is applied, the displacement of the processing jig is greater than the displacement of the base body.

2. The method for manufacturing a coil component according to claim 1, wherein the maximum distance between the end of the conductor and the outer surface of the flange after the processing jig has moved away from the end of the conductor is less than the amount of displacement of the processing jig when the predetermined load is applied.

3. A method for manufacturing a coil component according to claim 1 or 2, wherein, when the predetermined load is applied, the processing jig is in contact with the end of the conductor and the outer surface of the flange, and a portion of the processing jig that is not in contact with the end of the conductor and the outer surface of the flange is located on the shaft side of the outer surface of the flange.

4. A method for manufacturing a coil component according to any one of claims 1 to 3, wherein a groove is provided on the outer surface of the flange portion, the end of the conductor is positioned inside the groove, and when a predetermined load is applied, the processing jig is in contact with the end of the conductor, and a part of the processing jig that is not in contact with the end of the conductor is located on the shaft side of the groove.

5. A method for manufacturing a coil component according to any one of claims 1 to 3, wherein a recess is provided on the outer surface of the flange portion, the end of the conductor is positioned to cross the recess, and when the predetermined load is applied, the processing jig is in contact with the end of the conductor, and a part of the processing jig that is not in contact with the end of the conductor is located on the shaft side of the recess.

6. In the step of providing the end of the conductor, the end of the conductor is provided on the outer surface of the flange such that the lead wire, which connects the end of the conductor to the coil portion, is positioned outside the outer surface of the flange portion and the outer surface of the flange portion adjacent to it. A method for manufacturing a coil component according to any one of claims 1 to 5, wherein in the step of processing the end of the conductor, the end of the conductor is processed such that a portion of the lead wire located away from the processing jig is further away from the outer surface of the flange than before the predetermined load was applied.

7. A method for manufacturing a coil component according to any one of claims 1 to 6, wherein the end of the conductor and the portion in contact with the outer surface of the flange in the processing jig are made of urethane rubber or silicone rubber.

8. A method for manufacturing a coil component according to any one of claims 1 to 7, comprising the step of processing the end of the conductor, and then joining a solder film to the end of the conductor to form an external electrode including the end of the conductor and the solder film.

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