JP2022116787A - Coil component and method for manufacturing coil component - Google Patents

Abstract

To reduce voids generated in an exterior part.SOLUTION: A method for manufacturing a coil component includes: a step of winding a coated conducting wire 30 around a shaft 12 of a core 10 thereby to form a winding part 32, the core having the shaft 12 and a flange 14 provided at one end of the shaft 12; a step of forming lead-out parts 34a and 34b by leading out the coated conducting wire 30 from a pair of ends of the winding part 32, respectively; a step of forming external electrodes 60a and 60b to which the lead-out parts 34a and 34b are electrically connected, respectively; and a step of forming an exterior part 50 covering the entire of the winding part 32, the step including a step of covering, with a first resin material that forms a first exterior part 52, a first part 36 that is a part of the winding part 32, and a step of covering, with a second resin material that forms a second external part 54, a second part 38 of the winding part 32, the second part being different from the first part 36, after the step of covering with the first resin material.SELECTED DRAWING: Figure 1

Description

The present invention relates to a coil component and a method for manufacturing the coil component.

2. Description of the Related Art A coil component is known that has a core having a shaft portion and a flange portion provided at the end of the shaft portion, and a winding portion in which a coated conductive wire is wound around the shaft portion. In such a coil component, it is known to cover the winding portion with an exterior portion containing metal magnetic particles and a resin material in order to increase the inductance (for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2016-031960

Coil components are becoming smaller, and along with this, the conductor wire for forming the winding portion is becoming thinner. As the conductors become thinner, the adhesion between the conductors increases, making it more difficult for air to escape when forming the outer covering that covers the winding part. For this reason, voids may be formed inside and outside the exterior part due to air bubbles contained inside the resin material used for forming the exterior part and/or air present in gaps between the conductors. If voids are present inside the exterior, moisture entering from the outside tends to accumulate in the voids. In addition, if voids exist outside the exterior, the color tone of the appearance is spoiled, which not only causes malfunctions in image inspections, but also leads to exposure of conductors or defects in the shape of the exterior. put away.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to reduce voids generated in the exterior portion.

The present invention comprises a step of forming a winding portion by winding a coated conductive wire around the shaft portion of a core having a shaft portion and a flange portion provided at one end of the shaft portion, and a pair of ends of the winding portion. a step of forming a lead portion by drawing out each of the coated conductor wires from each; a step of forming an external electrode to which the lead portion is electrically connected; and a first covering with a resin material; and, after the step of covering with the first resin material, covering a portion of the winding portion different from the one portion with a second resin material serving as a second exterior portion, and covering the entire winding portion. and a step of forming an exterior covering the coil component.

In the above configuration, the first exterior portion may be configured so as to cover the lead portion and the portion where the coated conductor wire is led out from the end portion of the winding portion.

The said structure WHEREIN: A said 2nd exterior part can be set as the structure formed so that a said 1st exterior part may be covered.

In the above configuration, the first exterior portion is formed by curing the first resin material, and the second exterior portion is formed by curing the second resin material after forming the first exterior portion. can be configured.

In the above configuration, the first resin portion that becomes the first exterior portion is formed by applying the first resin material, and the second resin portion that becomes the second exterior portion is formed by applying the second resin material. is formed, and the first resin material and the second resin material are applied, and then the first resin material and the second resin material are simultaneously cured to remove the first exterior portion from the first resin portion. , the second exterior portion can be formed simultaneously from the second resin portion.

In the above configuration, the first exterior portion is formed so as to cover the entire circumference of the shaft portion when viewed from the axial direction of the shaft portion, and passes through the center of the shaft portion in the axial direction of the shaft portion. A configuration may be adopted in which the area of the first exterior portion in a parallel cross section is smaller than the area of the second exterior portion in a cross section parallel to the axial direction of the shaft portion.

In the above configuration, the first exterior portion is formed so as to cover the entire circumference of the shaft portion when viewed from the axial direction of the shaft portion, and passes through the center of the shaft portion in the axial direction of the shaft portion. A configuration may be adopted in which the area of the first exterior portion in a parallel cross section is larger than the area of the second exterior portion in a cross section parallel to the axial direction of the shaft portion.

In the above configuration, the first exterior portion is formed so as to cover a portion of the shaft portion, leaving a portion of the shaft portion at a contact portion that is an inner surface of the flange portion on the shaft portion side and contacts the shaft portion. and an area of the first exterior portion in a cross section passing through the winding portion and perpendicular to the axial direction of the shaft portion is smaller than an area of the second exterior portion in a cross section perpendicular to the axial direction of the shaft portion. It can be configured to be formed as follows.

In the above configuration, the first exterior portion is formed so as to cover a portion of the shaft portion, leaving a portion of the shaft portion at a contact portion that is an inner surface of the flange portion on the shaft portion side and contacts the shaft portion. and the area of the first exterior portion in a cross section passing through the winding portion and perpendicular to the axial direction of the shaft portion is larger than the area of the second exterior portion in a cross section perpendicular to the axial direction of the shaft portion. It can be configured to be formed as follows.

In the above configuration, the core may have a configuration in which the length of the shaft portion in the axial direction is longer than the length in the direction orthogonal to the axial direction.

In the above configuration, the core may have a configuration in which the length of the axial portion in the axial direction is shorter than the length in the direction orthogonal to the axial direction.

The present invention comprises a core having a shaft portion and a flange provided at one end of the shaft portion, a winding portion having a coated conductive wire wound around the shaft portion, and a portion covering a portion of the winding portion. an exterior portion that covers the entire winding portion, including a first exterior portion made of a resin material and a second exterior portion made of a resin material that covers a portion of the winding portion that is different from the one portion; It is a coil component comprising

According to the present invention, it is possible to reduce voids generated in the exterior portion.

1(a) to 1(f) are side views showing the method of manufacturing the coil component according to the first embodiment. 2(a) to 2(f) are side views showing the method of manufacturing the coil component according to Modification 1 of the first embodiment. 3A to 3F are side views showing a method of manufacturing a coil component according to Modification 2 of the first embodiment. 4(a) to 4(d) are side views showing a method of manufacturing a coil component according to a comparative example. 5(a) is a cross-sectional view along AA in FIG. 1(c), FIG. 5(b) is a cross-sectional view along AA in FIG. 2(c), and FIG. ) is a cross-sectional view along AA in FIG. 3(c). FIGS. 6(a) to 6(c) are cross sections showing an example in which the first exterior portion has a larger area than the second exterior portion. 7A to 7F are side views showing the method of manufacturing the coil component according to the second embodiment. 8A to 8F are side views showing a method of manufacturing a coil component according to a modification of the second embodiment. 9A to 9F are side views showing the method of manufacturing the coil component according to the third embodiment. 10(a) to 10(f) are side views showing a method of manufacturing a coil component according to a modification of the third embodiment. FIG. 11 is a cross-sectional view between AA in FIG. 9(f) and AA in FIG. 10(f). FIG. 12 is a cross-sectional view showing an example in which the first exterior portion has a larger area than the second exterior portion. FIG. 13 shows a coil component showing an example in which the mounting surface is parallel to the axial direction of the shaft portion.

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 embodiment. In addition, the same reference numerals are attached to constituent elements common to a plurality of drawings throughout the plurality of drawings. Please note that each drawing is not necessarily drawn to an exact scale for convenience of explanation.

[First embodiment]
1(a) to 1(f) are side views showing the method of manufacturing the coil component according to the first embodiment. 1(a) to 1(c) are side views when viewed from the +X side, and FIGS. 1(d) to 1(f) are side views when viewed from the +Y side. The X-axis, Y-axis, and Z-axis are orthogonal to each other. In FIGS. 1(a) to 1(f), each member may be hatched for clarity (the same applies to similar drawings below). 1(b) and 1(e) show the winding portion 32 and the like through the first exterior portion 52, and FIGS. 1(c) and 1(f) show the second exterior. The first exterior portion 52, the winding portion 32, and the like are illustrated with the portion 54 being seen through. The coil component may be a power inductor incorporated in a power supply line, an inductor used in a signal line, or others.

As shown in FIGS. 1(a) and 1(d), a T core having a shaft portion 12 whose axial direction is the Z-axis direction and a collar portion 14 joined to the end of the shaft portion 12 on the −Z side A certain core 10 is prepared. The illustrated core 10 is longer in the Z-axis direction than in the X-axis and Y-axis directions. By adopting such a structure, the length of the exterior portion 50 in the axial direction is increased, so that the effects of the present invention are enhanced. The effect of the present invention can be obtained even if the length in the Z-axis direction of the core 10 is equal to or shorter than the length in the X-axis direction and the Y-axis direction. The coated conducting wire 30 is wound around the shaft portion 12 of the core 10 to form a winding portion 32, and the coated conducting wire 30 is pulled out from a pair of ends of the winding portion 32 toward the collar portion 14 to lead out portions 34a. and 34b. For example, the lead-out portion 34 a corresponds to the winding start side when the coated conductor 30 is wound around the shaft portion 12 , and is drawn out from the −Z side end portion of the winding portion 32 toward the collar portion 14 . The drawn-out portion 34b corresponds to the winding end side, and is drawn out from the end portion on the +Z side of the winding portion 32 toward the collar portion 14 . The lead-out portions 34a and 34b are led out into a recess 22 formed in a surface 20 of the collar portion 14 opposite to the shaft portion 12. As shown in FIG. A metal film 24 is formed on the inner surface of the recess 22 . After drawing out the lead portions 34a and 34b into the recess 22, the lead portions 34a and 34b are electrically connected to the metal film 24 to form the external electrodes 60a and 60b.

For the core 10, a molded body having a shaft portion 12 and a flange portion 14 is formed by filling a magnetic paste, which is a mixture of magnetic powder and resin, into a cavity of a mold and press-molding the molded body. It is formed by performing a heat treatment (for example, at about 200° C.) at a low temperature. Ferrite magnetic powder or metal magnetic powder, for example, is used as the magnetic powder. As the ferrite magnetic powder, for example, a ferrite material such as Ni--Zn or Mn--Zn is used. Examples of metal magnetic powders include soft magnetic alloy materials such as Fe--Si--Cr, Fe--Si--Al, and Fe--Si--Cr--Al systems, magnetic metal materials such as Fe or Ni, and amorphous magnetic metal materials. , or a nanocrystalline magnetic metal material or the like is used. As the resin, a resin having excellent insulating properties such as polyvinyl butyral (PVB) resin or epoxy resin is used.

Note that the core 10 may be formed by processing a large lump of molded body to obtain a molded body having the shaft portion 12 and the collar portion 14, and then heat-treating this molded body. The heat treatment may be performed before processing into a compact having the shaft portion 12 and the collar portion 14 . Further, the core 10 is not limited to being formed by hardening magnetic powder with resin, and may be formed by binding magnetic powder together with an inorganic substance. In this case, the core 10 is formed by heat-treating, for example, 600.degree. C. to 1100.degree.

The axial portion 12 of the core 10 has, for example, a rectangular cross-sectional shape parallel to the XY plane. The collar portion 14 is, for example, a polygonal prism having a thickness in the axial direction (Z-axis direction) of the shaft portion 12 . The shaft portion 12 may have a circular cross-sectional shape, an elliptical shape, a polygonal shape with pentagons or more, or a combination thereof. The collar portion 14 may be a cylinder having a thickness in the axial direction of the shaft portion 12, an elliptical cylinder, a polygonal cylinder, or a combination thereof. The shaft portion 12 is smaller than the outer shape of the flange portion 14 and is joined to the vicinity of the center of the flange portion 14 . The size of the core 10 is, for example, 0.9 mm to 3 mm in each of the X-axis direction, Y-axis direction, and Z-axis direction. The dimensions in the X-axis direction and the Y-axis direction may or may not be equal, and the dimension in the Z-axis direction may be the maximum or the minimum among the dimensions in the X-axis direction, the Y-axis direction, and the Z-axis direction. may be, or may be neither. The core 10 has a relative magnetic permeability of 30 to 800 and a specific resistance of 1×10 ⁶ Ω·cm or more.

The metal film 24 is formed by, for example, forming a base layer by sputtering or applying a conductive paste, and then forming a plated layer on the base layer by plating. The metal film 24 is a laminated film in which plating layers such as a nickel layer and a tin layer are provided on an underlying layer such as copper, silver, palladium, or a silver-palladium alloy.

The winding portion 32 is formed by winding the coated conductive wire 30 around the shaft portion 12 while being in contact with each other. The winding portion 32 may be formed by winding the coated conductive wire 30 on the surface of the shaft portion 12 in a single layer, or may be wound by stacking a plurality of layers. Alternatively, the wound portion 32 may be formed by so-called α-winding, in which the coated conductive wire 30 is wound first at the central portion and then wound toward both ends of the coated conductive wire 30 .

In the coated conductor 30, the peripheral surface of a core wire made of copper, for example, is covered with an insulating coating made of polyimide. The core wire may be made of a metal other than copper, such as silver, palladium, or a silver-palladium alloy. The insulating coating may be made of an insulating material other than polyamideimide, and may be made of a resin material such as polyamideimide, polyurethane, or polyester. The cross-sectional shape of the core wire may be circular or rectangular. An adhesive layer may be provided on the peripheral surface of the insulating coating.

In the external electrodes 60a and 60b, flux is applied to the end portions of the lead portions 34a and 34b located within the recesses 22, and then heated together with solder to peel off the insulating coating of the lead portions 34a and 34b and expose the core wires. , formed by joining this core wire to the metal film 24 by soldering,

As shown in FIGS. 1(b) and 1(e), by covering only a portion (referred to as a first portion 36) of the winding portion 32 with a first resin material in which a magnetic material and a resin are mixed, a first exterior portion is formed. form 52; For example, the first exterior portion 52 is formed by applying the first resin material only to the first portion 36 of the winding portion 32 by brush coating, roller transfer, dispensing, or the like to form the first resin portion and then curing the material. . In the first embodiment, the first exterior portion 52 covers the lead-out portion 34a and the portion 40a where the coated conductive wire 30 is pulled out from the end of the encircling portion 32 as the lead-out portion 34a. is formed over only the first portion 36 of the . The first exterior portion 52 is formed so as to cover the entire circumference of the shaft portion 12 at the contact portion 18 which is the inner surface of the flange portion 14 on the shaft portion 12 side and contacts the shaft portion 12 .

The first resin material used to form the first exterior portion 52 is formed by mixing ferrite and epoxy resin, for example, but may be formed by mixing other magnetic material and resin. The first resin material may contain a non-magnetic material such as silica particles. The resin contained in the first resin material is a thermosetting resin with excellent insulating properties, such as epoxy resin, polyimide resin, polystyrene (PS) resin, high density polyethylene (HDPE) resin, polyoxymethylene (POM) resin. , polycarbonate (PC) resin, polyvinylidene fluoride (PVDF) resin, phenolic (Phenolic) resin, polytetrafluoroethylene (PTFE) resin, polybenzoxazole (PBO) resin, or coating the windings in wound coil parts It may be any known resin other than the above used for the purpose.

As shown in FIGS. 1(c) and 1(f), by covering the second portion 38 other than the first portion 36 of the winding portion 32 with a second resin material obtained by mixing a magnetic material and a resin, a second exterior portion is formed. form 54; For example, the second exterior portion 54 is formed by applying the second resin material to the second portion 38 of the winding portion 32 by brush coating, roller transfer, dispensing, or the like to form the second resin portion and then curing the material. In the first embodiment, the second exterior portion 54 is formed to cover the second portion 38 of the winding portion 32 and the first exterior portion 52 . As a result, the exterior portion 50 that is composed of the first exterior portion 52 and the second exterior portion 54 and covers the entire winding portion 32 is formed. The exterior part 50 has a relative magnetic permeability of 3 to 30 and a specific resistance of 1×10 ⁷ Ω·cm or more.

The second resin material used to form the second exterior portion 54 is formed by mixing ferrite and epoxy resin, for example, but may be formed by mixing other magnetic material and resin. The second resin material may be made of the same magnetic material and the same resin as the first resin material, or at least one of the magnetic material and the resin may be different. Different functions can be imparted to the first exterior portion 52 and the second exterior portion 54 by using different materials for the first resin material and the second resin material. The same magnetic material may be the same average particle size of the magnetic particles and the same elemental composition of the magnetic particles, the same average particle size but different composition, or the different average particle size. The composition may be the same. The same average particle size means that the difference in average particle size is 5% or less. The same composition means that the difference in composition ratio of elements is 5 wt % (weight percent) or less. The average particle size can be obtained, for example, by observing the cross section of the first exterior portion 52 and the second exterior portion 54, and using scanning electron microscope images containing several hundred magnetic particles present in each exterior portion to determine the area of each particle. can be obtained by obtaining the area-average particle size when approximating to a circle.

As described above, the coil component according to the first embodiment is formed. Although the size of the coil component is not particularly limited, it is, for example, 1 mm to 3 mm in each of the X-axis, Y-axis and Z-axis directions, and for example 1.6 mm to 8 mm in the X-axis and Y-axis directions. 0 mm, and 1.0 mm to 4.5 mm in the Z-axis direction.

[Modification of First Embodiment]
2(a) to 2(f) are side views showing the method of manufacturing the coil component according to Modification 1 of the first embodiment. 2(a) to 2(c) are side views when viewed from the +X side, and FIGS. 2(d) to 2(f) are side views when viewed from the +Y side. In the modification 1 of the first embodiment, as shown in FIGS. 2A and 2D, the shaft portion 12 whose axial direction is the Z-axis direction and the −Z side end of the shaft portion 12 A core 11, which is a drum core, is prepared, which has a flange portion 14 that is joined and a flange portion 16 that is joined to the end of the shaft portion 12 on the +Z side. The illustrated core 11 is longer in the Z-axis direction than in the X-axis and Y-axis directions. Since other manufacturing steps are the same as those of the first embodiment, description thereof is omitted.

3A to 3F are side views showing a method of manufacturing a coil component according to Modification 2 of the first embodiment. 3(a) to 3(c) are side views when viewed from the +X side, and FIGS. 3(d) to 3(f) are side views when viewed from the +Y side. In Modified Example 2 of the first embodiment, the second exterior portion 54 is formed without covering the first exterior portion 52, as shown in FIGS. 3(c) and 3(f). Since other manufacturing steps are the same as those of the first embodiment, description thereof is omitted.

[Form of comparison]
4(a) to 4(d) are side views showing a method of manufacturing a coil component according to a comparative example. 4(a) and 4(b) are side views when viewed from the +X side, and FIGS. 4(c) and 4(d) are side views when viewed from the +Y side.

As shown in FIGS. 4A and 4C, a winding portion 132 is formed by winding a coated conducting wire 130 around a shaft portion 112 of a core 110 having a shaft portion 112 and a flange portion 114, Lead portions 134a and 134b are formed by leading out the coated conductors 130 from a pair of ends of the encircling portion 132, respectively. External electrodes 160a and 160b are formed by electrically connecting the ends of the lead portions 134a and 134b drawn into the recess 122 formed in the surface 120 of the collar portion 114 to the metal film 124. FIG. The manufacturing method of each part is the same as that of the first embodiment except that the method of forming the exterior part 150 is different, so the description is omitted.

As shown in FIGS. 4(b) and 4(d), by covering the entire winding portion 132 with a resin material in which a magnetic material and a resin are mixed, an exterior portion 150 that covers the entire winding portion 132 is formed. For example, the exterior portion 150 is formed by applying a resin material to the entire winding portion 132 by brush coating, roller transfer, dispensing, or the like, and then curing the resin material. As described above, a coil component according to the comparative embodiment is formed.

According to the comparative embodiment, by covering the entire winding portion 132 with a resin material at once, the exterior portion 150 that covers the entire winding portion 132 is formed. With the miniaturization of coil components, the coated conductive wire 130 has become thinner, and the adhesion of the coated conductive wire 130 has increased. Therefore, in the case where the exterior portion 150 is formed by covering the entire encircling portion 132 with a resin material at once, the coating amount of the resin material is large and the contact area between the resin material and the encircling portion 132 is large. It becomes difficult to escape the air bubbles contained and/or the air present in the gaps of the film-coated conducting wire 30 . Therefore, many voids are generated inside and outside the exterior part 150 .

Further, when a resin material in which a magnetic material and a resin are mixed is used to form the exterior portion 150, the proportion of the magnetic material is increased as the thickness of the exterior portion 150 becomes smaller due to the miniaturization of the coil components. . As a result, the wetting and spreading properties of the resin material are reduced, and voids are more likely to be formed inside and outside the exterior part 150 .

If many voids are formed inside and outside the exterior part 150, unevenness is formed on the surface of the exterior part 150, resulting in appearance defects and/or dimensional abnormalities. In addition, when the exterior part 150 is formed using a resin material that is a mixture of a magnetic material and a resin, voids are formed, which causes variations in the filling rate of the magnetic material, resulting in unstable electrical characteristics such as inductance. turn into.

According to the first embodiment and its modified examples 1 and 2, the first portion 36, which is a part of the winding portion 32, is covered with the first resin material that becomes the first exterior portion 52, and is covered with the first resin material. Later, by covering the second portion 38 different from the first portion 36 of the encircling portion 32 with a second resin material that becomes the second exterior portion 54, the exterior portion 50 that covers the entire encircling portion 32 is formed. Thus, by forming the exterior part 50 in a plurality of steps, voids generated inside and outside the exterior part 50 are reduced compared to the case where the exterior part 150 is formed at once as in the comparative embodiment. be able to. That is, by forming the first exterior portion 52 by covering only the first portion 36, which is a part of the encircling portion 32, with the first resin material, the amount of application of the first resin material is small and the first resin material is Since the area in contact with 32 becomes smaller, air bubbles contained in the inside of the first resin material and air present in gaps between the coated conductors 30 are easily released, and voids generated inside and outside the first exterior portion 52 are reduced. Become. Similarly, in the second exterior portion 54, since the amount of the second resin material applied is small and the area where the second resin material is in contact with the winding portion 32 is small, voids generated inside and outside the second exterior portion 54 are reduced. less. Therefore, voids generated inside and outside the exterior part 50 are reduced. By reducing the voids inside and outside the exterior part 50, unevenness is less likely to be formed on the surface of the exterior part 50, and the occurrence of appearance defects, dimensional abnormalities, and the like is reduced. In addition, the exterior part 50 covering the whole winding part 32 means that the outer surface of the winding part 32 is not exposed from the exterior part 50 and covers 100%.

Further, when the first exterior portion 52 is made of a first resin material that is a mixture of a magnetic material and resin, and the second exterior portion 54 is made of a second resin material that is a mixture of a magnetic material and resin, the exterior portion 50 By reducing the number of internal voids, variations in the filling rate of the magnetic material can be suppressed. As a result, variations in electrical characteristics such as inductance can be suppressed. In addition, since the voids are reduced, it is possible to obtain the exterior portion 50 with a high filling rate of the magnetic material.

Further, in the first embodiment and its modified examples 1 and 2, the first exterior portion 52 includes the lead portion 34a, the portion 40a where the coated conductor 30 is led out from the end of the winding portion 32 as the lead portion 34a, formed to cover the Since the coated conductors 30 are densely provided in the vicinity of the portion 40a where the coated conductors 30 are pulled out from the end portion of the encircling portion 32 as the lead-out portion 34a, there is a large amount of air present in the gaps between the coated conductors 30 . For this reason, first, the first exterior portion 52 is formed so as to cover the portion 40a where the lead wire 30 with the coating is pulled out as the lead portion 34a from the end portion of the winding portion 32, so that the air present in the vicinity of the portion 40a can be released. Thus, voids generated inside and outside the first exterior portion 52 are reduced. Further, by forming the first exterior portion 52 so as to cover the drawn-out portion 40a, it is possible to seal or narrow the path of the air that flows from the winding portion 32 along the drawn-out portion 34a. As a result, when the second exterior portion 54 is formed after the first exterior portion 52 is formed, the flow of air toward the first exterior portion 52 is suppressed, and the air tends to flow outward. Voids generated inside and outside of 50 are reduced. In addition, by sealing or narrowing the path of the air that flows from the encircling portion 32 along the drawn portion 34a, moisture is prevented from entering the encircling portion 32 along the drawn portion 34a.

In addition, in the first embodiment and its modified examples 1 and 2, the lead-out portion 34 a is the lead-out portion on the winding start side when the coated conductor 30 is wound around the shaft portion 12 . The lead-out portion 34a on the winding start side is positioned at either the +Z side end or the -Z side end of the winding portion 32. As shown in FIG. On the other hand, it is not possible to specify the position of the lead-out portion 34b on the winding end side depending on the number of windings of the coated conductive wire 30 for obtaining a desired inductance. Therefore, the amount of air existing in the gap of the coated conductor 30 is large, and the air in the portion where the coated conductor 30 is pulled out from the end of the winding part 32 is effectively released, thereby reducing voids generated inside and outside the exterior part 50. In view of this, it is preferable that the first armor portion 52 is formed so as to cover the lead-out portion 34a on the winding start side and the portion 40a through which the coated conductive wire 30 is led out as the lead-out portion 34a from the end of the winding portion 32. .

In addition, in the first embodiment and its modified example 1, the second exterior portion 54 is formed so as to cover the first exterior portion 52 . Accordingly, it is possible to prevent moisture from entering the winding portion 32 along the interface between the first exterior portion 52 and the second exterior portion 54 . Moreover, since the boundary between the first exterior portion 52 and the second exterior portion 54 cannot be seen from the outside, a good appearance can be obtained. Furthermore, when the second exterior portion 54 is formed so as to cover the first exterior portion 52, the first exterior portion 52 is formed to be thin. Air bubbles contained in the interior are easily released, and voids generated in the interior of the first exterior portion 52 are further reduced.

Further, in the first embodiment and its modified examples 1 and 2, the first exterior portion 52 is formed by applying the first resin material to the first portion 36 of the winding portion 32 and curing the first exterior portion 52 . After the portion 52 is formed, a second exterior portion 54 is formed by applying a second resin material to the second portion 38 of the winding portion 32 and curing the material. By curing the first resin material and the second resin material separately in this manner, the amount of resin on the surface of the first exterior portion 52 increases, and moisture enters the winding portion 32 through the first exterior portion 52. can be suppressed.

In addition, in the first embodiment and its modified examples 1 and 2, the cores 10 and 11 have a length in the axial direction (Z-axis direction) of the shaft portion 12 in directions (X-axis direction and Y-axis direction) perpendicular to the axial direction. axial direction). Thereby, the number of turns of the winding portion 32 can be increased, and a large inductance can be obtained.

FIG. 5(a) is a cross-sectional view between AA in FIG. 1(c), FIG. 5(b) is a cross-sectional view between AA in FIG. 2(c), and FIG. It is a sectional view between AA of 3(c). 5A to 5C are cross sections passing through the center of the shaft portion 12 and parallel to the axial direction (Z-axis direction) of the shaft portion 12. FIG. As shown in FIGS. 5(a) to 5(c), the area of the first exterior portion 52 is smaller than the area of the second exterior portion 54, and the area of the second exterior portion 54 is the area of the first exterior portion 52. greater than In this manner, in a cross section passing through the center of the shaft portion 12 and parallel to the axial direction of the shaft portion 12, the first exterior portion 52 is formed to have a smaller area than the second exterior portion 54. The application amount of the first resin material used for forming 52 is reduced. This prevents the first resin material from being applied to an unintended location due to dripping of the first resin material or the like. Therefore, blocking or narrowing of the air discharge path is suppressed, and voids generated inside and outside the exterior part 50 can be reduced. The cross-sectional area of the first exterior portion 52 may be 1/3 or less, 1/4 or less, or 1/5 or less of the cross-sectional area of the second exterior portion 54 .

In the first embodiment and its modifications 1 and 2, in a cross section passing through the center of the shaft portion 12 and parallel to the axial direction of the shaft portion 12, the first exterior portion 52 is larger than the second exterior portion 54. It may be formed in a large area. FIGS. 6(a) to 6(c) are cross sections showing an example in which the first exterior portion 52 has a larger area than the second exterior portion 54. FIG. In this case, the application amount of the second resin material used for forming the second exterior portion 54 is small, and the area where the second resin material is in contact with the winding portion 32 becomes small, so that voids generated inside the second exterior portion 54 are reduced. can be less.

When the second exterior portion 54 is formed to cover the first exterior portion 52 as in the first embodiment and its modification 1, the first exterior portion 52 and the second exterior portion 54 are laminated. If either the first exterior portion 52 or the second exterior portion 54 is thin, there is concern that the mechanical strength of the thinner exterior portion may decrease. Therefore, in the portion where the first exterior portion 52 and the second exterior portion 54 are laminated, it is preferable that the first exterior portion 52 and the second exterior portion 54 have approximately the same thickness. In this case, in a cross section passing through the center of the shaft portion 12 and parallel to the axial direction of the shaft portion 12 , the first exterior portion 52 is formed to have a smaller area than the second exterior portion 54 .

[Second embodiment]
7A to 7F are side views showing the method of manufacturing the coil component according to the second embodiment. 7(a) to 7(c) are side views when viewed from the +X side, and FIGS. 7(d) to 7(f) are side views when viewed from the +Y side. In the second embodiment, as shown in FIGS. 7(a) and 7(d), both the lead-out portions 34a and 34b are pulled out from the +Z side end portion of the winding portion 32 toward the collar portion 14. As shown in FIGS.

As shown in FIGS. 7(b) and 7(e), a lead portion 34b that covers the lead portion 34a and the portion 40a that draws out the coated conductor 30 from the end of the winding portion 32 as the lead portion 34a, A first exterior is formed by covering only a portion 40b for drawing out the coated conductor 30 from the end of the encircling portion 32 as a lead-out portion 34b and a portion of the encircling portion 32 (referred to as a first portion 36) so as to cover it with a first resin material. forming part 52;

As shown in FIGS. 7(c) and 7(f), the second exterior portion 54 is formed by covering the second portion 38 of the winding portion 32 other than the first portion 36 with the second resin material. In the second embodiment, the +Z side surface of the first exterior portion 52 and the +Z side surface of the second exterior portion 54 are substantially flush.

The details of the method of manufacturing the coil component according to the second embodiment are the same as those of the method of manufacturing the coil component according to the first embodiment, so the description is omitted. As described above, the coil component according to the second embodiment is formed.

[Modification of Second Embodiment]
8A to 8F are side views showing a method of manufacturing a coil component according to a modification of the second embodiment. 8(a) to 8(c) are side views when viewed from the +X side, and FIGS. 8(d) to 8(f) are side views when viewed from the +Y side. In a modification of the second embodiment, as shown in FIGS. 8(a) and 8(d), a core 11 that is a drum core having a shaft portion 12 and flanges 14 and 16 is prepared. Since other manufacturing steps are the same as those of the second embodiment, description thereof is omitted.

Also in the second embodiment and its modification, the first portion 36, which is a part of the winding portion 32, is covered with the first resin material that forms the first exterior portion 52, and after covering with the first resin material, the winding portion By covering the second portion 38 different from the first portion 36 of 32 with a second resin material that becomes the second exterior portion 54, the exterior portion 50 that covers the entire winding portion 32 is formed. As a result, voids generated inside and outside the exterior part 50 can be reduced.

In addition, in the second embodiment and its modification, the first exterior portion 52 covers the lead portion 34a and the portion 40a where the coated conductor 30 is led out from the end portion of the winding portion 32 as the lead portion 34a. It is formed so as to cover the lead-out portion 34b and the portion 40b from which the coated conductive wire 30 is led out as the lead-out portion 34b from the end portion of the winding portion 32 . As a result, the air around both the portions 40a and 40b from which the coated conductor 30 is pulled out from the end portion of the winding portion 32 is easily released, and voids generated inside and outside the first exterior portion 52 are reduced.

In the above-described second embodiment and its modification, the first exterior portion 52 covers a part of the winding portion 32 on the −Z side, which does not have the portions 40a and 40b for drawing out the coated conductor 30 from the end of the winding portion 32. may be formed. In this case, compared to the case where the first armor portion 52 is formed so as to cover the portions 40a and 40b from which the coated conductive wire 30 is led out from the end portion of the winding portion 32, even if the formation area of the first armor portion 52 is increased, the 1. Voids generated inside and outside the exterior portion 52 can be reduced. Therefore, the forming area of the second exterior portion 54 can be reduced, and voids generated inside and outside the second exterior portion 54 can be suppressed.

[Third embodiment]
9A to 9F are side views showing the method of manufacturing the coil component according to the third embodiment. 9(a) to 9(c) are side views when viewed from the +X side, and FIGS. 9(d) to 9(f) are side views when viewed from the +Y side. As shown in FIGS. 9A and 9D, a core 10a, which is a T core whose length in the Z-axis direction is shorter than the lengths in the X-axis direction and the Y-axis direction, is prepared. The coated conducting wire 30 is wound around the shaft portion 12 of the core 10a to form a winding portion 32, and the coated conducting wire 30 is pulled out from a pair of ends of the winding portion 32 toward the collar portion 14 to lead out portions 34a. and 34b. External electrodes 60a and 60b are formed by electrically connecting the lead portions 34a and 34b to the metal film 24 . The method of manufacturing the winding portion 32, the lead portions 34a and 34b, and the external electrodes 60a and 60b is the same as that of the first embodiment, so the description thereof is omitted.

As shown in FIGS. 9B and 9E, the first exterior portion 52 is formed by covering only a portion (referred to as the first portion 36) of the winding portion 32 with the first resin material. In the third embodiment, the first exterior portion 52 covers the lead portion 34a and the portion 40a where the coated conductive wire 30 is led out as the lead portion 34a from the end of the winding portion 32, and the lead portion 34b, Covers only the first portion 36 of the winding portion 32 so as to cover the portion 40b where the coated conductor 30 is pulled out as the lead portion 34b from the end portion of the winding portion 32, and the inner surface of the collar portion 14 on the shaft portion 12 side. It is formed so as to partially cover the outer periphery of the shaft portion 12 at the contact portion 18 in contact with the shaft portion 12 , leaving a portion thereof.

As shown in FIGS. 9C and 9F, the second exterior portion 54 is formed by covering the second portion 38 of the winding portion 32 other than the first portion 36 with the second resin material. In the third embodiment, the second exterior portion 54 is formed to cover the second portion 38 of the winding portion 32 without covering the first exterior portion 52 .

The details of the method of manufacturing the coil component according to the third embodiment are the same as those of the method of manufacturing the coil component according to the first embodiment, so the description is omitted. As described above, the coil component according to the third embodiment is formed.

[Modified example of the third embodiment]
10(a) to 10(f) are side views showing a method of manufacturing a coil component according to a modification of the third embodiment. 10(a) to 10(c) are side views when viewed from the +X side, and FIGS. 10(d) to 10(f) are side views when viewed from the +Y side. In a modification of the third embodiment, as shown in FIGS. 10(a) and 10(d), a core 11a, which is a drum core having a shaft portion 12 and flanges 14 and 16, is prepared. The length of the core 11a in the Z-axis direction is shorter than the length in the X-axis and Y-axis directions. Since other manufacturing steps are the same as those of the third embodiment, description thereof is omitted.

Also in the third embodiment and its modification, the first portion 36, which is a part of the winding portion 32, is covered with the first resin material that becomes the first exterior portion 52, and after covering with the first resin material, the winding portion By covering the second portion 38 different from the first portion 36 of 32 with a second resin material that becomes the second exterior portion 54, the exterior portion 50 that covers the entire winding portion 32 is formed. Thereby, voids generated inside the exterior part 50 can be reduced.

In addition, in the third embodiment and its modification, the cores 10a and 11a are arranged such that the length in the axial direction (Z-axis direction) of the shaft portion 12 is perpendicular to the axial direction (X-axis direction and Y-axis direction). shorter than the length in Since the shaft portion 12 is short in this manner, the height can be reduced, and the size of the coil component can be reduced.

FIG. 11 is a cross-sectional view between AA in FIG. 9(f) and AA in FIG. 10(f). FIG. 11 is a cross section passing through the winding portion 32 and orthogonal to the axial direction (Z-axis direction) of the shaft portion 12 . For the sake of explanation, in FIG. 11, the drawn portions 34a and 34b, which are not shown in this cross section, are indicated by dashed lines (the same applies to FIG. 12, which will be described later). As shown in FIG. 11, the first exterior portion 52 covers the drawer portion 34a and the drawer portion 34b, and is formed slightly smaller on the side having the drawer portion 34a and the drawer portion 34b and one side adjacent to the side. . Since the second exterior portion 54 is formed after the formation of the first exterior portion 52, the corner portion where the first exterior portion 52 and the second exterior portion 54 meet is occupied by the previously formed first exterior portion 52. The second exterior portion 54 occupies the non-existent corner portion. Therefore, the area of the first exterior portion 52 is smaller than the area of the second exterior portion 54 , and the area of the second exterior portion 54 is greater than the area of the first exterior portion 52 .

In the third embodiment and its modification, the first exterior portion 52 is a portion of the outer circumference of the shaft portion 12 at the contact portion 18 that is the inner surface of the flange portion 14 on the shaft portion 12 side and is in contact with the shaft portion 12. It is formed so as to leave it and partially cover it. In the first and second embodiments and their modifications, the first exterior portion 52 is formed by applying the first resin material while rotating the cores 10 and 11. In the modified example, the first exterior portion 52 can be formed by applying the first resin material without rotating the cores 10a and 11a, so the easiness of manufacturing is improved. Further, in order to provide a portion of the encircling portion 32 where the first resin material is not applied, it is preferable to apply the first resin material once rather than applying the first resin material multiple times. When the first resin material is applied once, it is difficult to apply the first resin material to exactly half the outer circumference of the encircling portion 32 , so it is preferable to apply the first resin material to a range smaller than half the outer circumference of the encircling portion 32 . . Therefore, as shown in FIG. 11 , the first exterior portion 52 is formed to have a smaller area than the second exterior portion 54 in a cross section passing through the winding portion 32 and perpendicular to the axial direction of the shaft portion 12 . The cross-sectional area of the first exterior portion 52 may be 1/3 or less, 1/4 or less, or 1/5 or less of the cross-sectional area of the second exterior portion 54 . The second resin material only covers the portion of the encircling portion 32 that is not covered with the first exterior portion 52 , and it is not necessary to provide a portion of the encircling portion 32 that is not coated with the second resin material. There is no problem even if the resin material is applied multiple times.

In the third embodiment and its modification, the first exterior portion 52 is formed to have a larger area than the second exterior portion 54 in a cross section passing through the winding portion 32 and perpendicular to the axial direction of the shaft portion 12 . may be used. FIG. 12 is a cross-sectional view showing an example in which the first exterior portion 52 has a larger area than the second exterior portion 54 . As shown in FIG. 12, the first exterior portion 52 covers the drawer portion 34a and the drawer portion 34b, and is formed on the side having the drawer portion 34a and the drawer portion 34b and one side adjacent to the side having the drawer portion 34a and the drawer portion 34b. . Since the second exterior portion 54 is formed after the formation of the first exterior portion 52, the corner portion where the first exterior portion 52 and the second exterior portion 54 meet is occupied by the previously formed first exterior portion 52. there is Therefore, the area of the first exterior portion 52 is larger than the area of the second exterior portion 54 , and the area of the second exterior portion 54 is smaller than the area of the first exterior portion 52 .

As shown in FIG. 12 , the first exterior portion 52 may be formed to have a larger area than the second exterior portion 54 in a cross section passing through the winding portion 32 and orthogonal to the axial direction of the shaft portion 12 . By forming the first exterior portion 52 to be large, it covers the lead portion 34a and the portion 40a where the coated conductor 30 is led out as the lead portion 34a from the end of the encircling portion 32, and also covers the lead portion 34b and the encircling portion 32. It becomes easy to cover the portion 40b from which the coated conductive wire 30 is pulled out as the lead portion 34b from the end portion. As a result, the air around both the portions 40a and 40b from which the coated conductor 30 is pulled out from the end portion of the winding portion 32 is easily released, and voids generated inside the first exterior portion 52 are reduced. Even in this case, the second resin material only covers the portion of the encircling portion 32 that is not covered with the first exterior portion 52, and thus there is no need to provide a portion of the encircling portion 32 that is not coated with the second resin material. There is no problem even if the second resin material is applied multiple times.

In each of the above-described embodiments and their modifications, the surface 20 (mounting surface) of the flange 14 on which the external electrodes 60a and 60b are provided is perpendicular to the axial direction (Z-axis direction) of the shaft portion 12 as an example. , but is not limited to this case. FIG. 13 shows a coil component showing an example in which the mounting surface is parallel to the axial direction of the shaft portion 12 . As shown in FIG. 13 , the flange 14 may be provided with the external electrode 60 a , the flange 16 may be provided with the external electrode 60 b , and the mounting surface 26 may be parallel to the axial direction of the shaft 12 . The axial length of the shaft portion 12 of the core 11b may be longer or shorter than the length in the direction orthogonal to the axial direction. Further, when the length of the coil component is L, the depth is W, and the height is H, the relationship of L>W≧H is generally established. The axial direction of the shaft portion 12 may match the length direction of the coil component, or may match the width direction. When the axial direction of the shaft portion 12 coincides with the length direction of the coil component, the number of turns of the winding portion 32 can be increased and a large inductance can be obtained.

In each of the above-described embodiments and modifications thereof, the first exterior portion 52 is formed by applying the first resin material to the first portion 36 of the winding portion 32 and curing the material, thereby forming the first exterior portion 52. After that, the case where the second exterior portion 54 is formed by applying the second resin material to the second portion 38 of the winding portion 32 and curing the second resin material is shown as an example. However, the present invention is not limited to this case, and the first resin material is applied to the first portion 36 of the winding portion 32 to form the first resin portion that becomes the first exterior portion 52 , and the second portion 38 of the winding portion 32 is coated with the first resin material. A second resin portion that becomes the second exterior portion 54 is formed by applying a second resin material, and after applying the first resin material and the second resin material, the first resin material and the second resin material are simultaneously cured. The first exterior portion 52 may be formed from the first resin portion, and the second exterior portion 54 may be formed from the second resin portion at the same time. Thereby, the number of manufacturing steps can be reduced.

In each of the above-described embodiments and modifications thereof, the first resin material may be degassed under reduced pressure or degassed under pressure after the first resin material is applied. Similarly, degassing under reduced pressure or degassing under pressure may be performed on the second resin material after applying the second resin material. Thereby, the voids generated inside the exterior part 50 can be further reduced.

In each of the above-described embodiments and modifications thereof, the first exterior portion 52 and the second exterior portion 54 may be made of a resin material that does not contain a magnetic material, or may be made of a non-magnetic material such as silica particles and a resin. It may be formed of a resin material containing Further, in each of the above-described embodiments and modifications thereof, a non-magnetic portion having no magnetic properties is provided between the winding portion 32 and the first exterior portion 52 and/or between the winding portion 32 and the second exterior portion 54. may be

In each of the above-described embodiments and modifications thereof, the case where the exterior part 50 is formed in two stages, the first exterior part 52 and the second exterior part 54, is shown as an example. It may be formed separately.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention described in the scope of claims. Change is possible.

Reference Signs List 10, 10a, 11, 11a, 11b Core 12 Shaft 14, 16 Flange 18 Contact 20 Surface 22 Recess 24 Metal film 26 Mounting surface 30 Coated conductor 32 Wrapping 34a, 34b Drawer 36 First part 38 Second Part 40a, 40b Leading part 50 Exterior part 52 First exterior part 54 Second exterior part 60a, 60b External electrode

Claims (12)

forming a winding portion by winding a coated conductive wire around the shaft portion of a core having a shaft portion and a flange portion provided at one end of the shaft portion;
a step of forming lead portions by drawing out the coated conductive wires from a pair of ends of the encircling portion;
forming an external electrode to which the lead portion is electrically connected;
a step of covering a portion of the winding portion with a first resin material to form a first exterior portion; A method of manufacturing a coil component, comprising the step of covering with a material, and the step of forming an exterior portion that covers the entire winding portion. 2. The method of manufacturing a coil component according to claim 1, wherein the first exterior portion is formed so as to cover the lead portion and a portion where the coated conductor wire is led out from an end portion of the winding portion. 3. The method of manufacturing a coil component according to claim 1, wherein said second exterior portion is formed so as to cover said first exterior portion. forming the first exterior portion by curing the first resin material;
4. The method of manufacturing a coil component according to claim 1, wherein the second exterior portion is formed by curing the second resin material after forming the first exterior portion. forming a first resin portion to be the first exterior portion by applying the first resin material;
forming a second resin portion to be the second exterior portion by applying the second resin material;
After the first resin material and the second resin material are applied, the first resin material and the second resin material are simultaneously cured to remove the first exterior portion from the first resin portion and the second resin material. 4. The method of manufacturing a coil component according to claim 1, wherein the second exterior portion is formed from a resin portion at the same time. The first exterior portion is formed so as to cover the entire circumference of the shaft viewed from the axial direction of the shaft, and passes through the center of the shaft and is parallel to the axial direction of the shaft. The coil according to any one of claims 1 to 5, wherein the area of the first exterior portion is formed to be smaller than the area of the second exterior portion in a cross section parallel to the axial direction of the shaft portion. How the parts are made. The first exterior portion is formed so as to cover the entire circumference of the shaft viewed from the axial direction of the shaft, and passes through the center of the shaft and is parallel to the axial direction of the shaft. The coil according to any one of claims 1 to 5, wherein the area of the first exterior portion is formed to be larger than the area of the second exterior portion in a cross section parallel to the axial direction of the shaft portion. How the parts are made. The first exterior portion is formed so as to cover a portion of the shaft portion, leaving a portion of the shaft portion, at a contact portion which is an inner surface of the flange portion on the shaft portion side and is in contact with the shaft portion, and The area of the first exterior portion in a cross section passing through the winding portion and perpendicular to the axial direction of the shaft portion is formed so as to be smaller than the area of the second exterior portion in a cross section perpendicular to the axial direction of the shaft portion. 6. The method for manufacturing a coil component according to any one of claims 1 to 5. The first exterior portion is formed so as to cover a portion of the shaft portion, leaving a portion of the shaft portion, at a contact portion which is an inner surface of the flange portion on the shaft portion side and is in contact with the shaft portion, and The area of the first exterior portion in a cross section passing through the winding portion and perpendicular to the axial direction of the shaft portion is formed to be larger than the area of the second exterior portion in a cross section perpendicular to the axial direction of the shaft portion. 6. The method for manufacturing a coil component according to any one of claims 1 to 5. 10. The method of manufacturing a coil component according to claim 1, wherein said core has a length in the axial direction of said shaft portion longer than a length in a direction orthogonal to said axial direction. 10. The method of manufacturing a coil component according to claim 1, wherein said core has a length in an axial direction of said shaft portion that is shorter than a length in a direction orthogonal to said axial direction. a core having a shaft and a flange provided at one end of the shaft;
a winding portion in which a coated conductive wire is wound around the shaft;
A first exterior portion made of a resin material provided to cover a portion of the winding portion, and a second exterior portion made of a resin material provided to cover a portion different from the portion of the winding portion, A coil component comprising: an exterior portion that covers the entire winding portion.

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