JP2008071858A - Manufacturing method of coil component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a quantitatively stable coil component capable of preventing contact between a drum core and a perimeter core and having an inductance value of the coil component which is small in change even in a minute current region. <P>SOLUTION: A resin coating is applied to the first side face 21A of a first collar 21 and cured to form a coating layer 8A. Then, a resin coating is applied to the first side face 22A of a second collar 22 and cured to form a coating layer 8B. A winding 5 is wound around the winding portion 23 of the drum core 2. The drum core 2, a first divided core 6 and a second divided core 7 are combined. More specifically, a first projection 61 and a second projection 62, and a first projection 71 and a second projection 72 are made to abut on the coating layer 8A and the coating layer 8B, respectively. Then, adhesives 9A, 9B, 9C and 9D composed of non-magnetic resins are injected into the clearances between the inner curved surface 6A and the coating layers 8A and 8B and the clearances between the inner curved surface 7A and the coating layers 8A and 8B and cured. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a coil component, and more particularly to a method for manufacturing a coil component in which an inductance value is stabilized in a minute current region.

Conventionally, a coil component including a choke coil having a drum core and an outer peripheral core and having a conductive wire wound around the drum core is disposed in the electric circuit. In this coil component, in order to obtain desired characteristics, it is necessary to form a gap (gap) between the drum core forming the magnetic path and the outer core. The coil component is manufactured by combining the drum core around which the conductive wire is wound and the outer peripheral core so as to form a gap, and then applying an adhesive to the gap to bond the drum core and the outer peripheral core. (For example, refer to Patent Document 1).
JP 2001-338817 A

  However, in the conventional coil component manufacturing method, after the adhesive is injected between the drum core and the outer core, the drum core and the outer core come into contact with each other, and the adhesive is cured in a state where the drum core and the outer core are in contact with each other. There was a case. As a result, the inductance value L increases in the minute current region. Then, the response speed of the power supply circuit IC included in the electric circuit is slow, and the voltage conversion efficiency of the power supply circuit may be deteriorated. In this case, loss occurs, which causes a problem that the life of the battery connected to the circuit is reduced.

  Accordingly, an object of the present invention is to provide a quantitatively stable method of manufacturing a coil component that can prevent contact between the drum core and the outer peripheral core and has a small change in the inductance value of the coil component even in a minute current region. To do.

  In order to achieve the above object, the present invention provides a drum core having a columnar core part and a pair of flanges provided at both ends of the core part, a winding wound around the core part, and a drum core. And an electrode provided on at least one of the drum core and the outer core and connected to the end of the winding. The outer core faces the outer peripheral portion of the pair of flanges. An outer core facing surface is defined, and a pair of flanges provides a method of manufacturing a coil component in which a flange facing surface facing the outer core facing surface is defined.

  And the manufacturing method of the said coil components is the coating process which coats nonmagnetic resin to at least any one of a collar part opposing surface and an outer periphery core opposing surface, the hardening process which hardens resin, and an outer periphery core opposing surface The drum core and the outer peripheral core are combined so that the flange facing surface faces the flange portion through the resin.

  According to this manufacturing method, it can prevent that the outer periphery core opposing surface of an outer periphery core and the collar facing surface of a pair of collar part contact, Between an outer periphery core opposing surface and a collar facing surface A magnetic gap can be reliably formed. Therefore, it is possible to provide a quantitatively stable coil component with a small change in inductance value even in a minute current region. Furthermore, it is possible to provide a coil component having good direct current superposition characteristics.

  Here, the coating process includes a first coating process for coating one of the pair of collars on one collar-facing surface, and a second coating process for coating the resin on the other collar-facing surface of the pair of collars; And the curing step includes a first curing step for curing the resin coated on the one buttocks facing surface and a second curing step for curing the resin coated on the other buttocks facing surface, It is preferable to perform the first curing process after performing the first coating process, and then perform the second curing process after performing the second coating process.

  According to such a manufacturing method, the step of coating and curing the resin on one collar-facing surface of the pair of collars and the step of coating and curing the resin on the other collar-facing surface of the pair of collars are separated. Therefore, the resin layer can be reliably formed on the pair of flanges.

  According to the method for manufacturing a coil component of the present invention, it is possible to prevent the contact between the drum core and the outer core, and to provide a quantitatively stable coil component in which the inductance value of the coil component is small even in a minute current region. Can do.

  A method for manufacturing a coil component according to an embodiment of the present invention will be described with reference to FIGS. First, the coil component manufactured by the manufacturing method will be described. The coil component 1 shown in FIG. 1 has an outer shape of about 3 mm square and is surface-mounted with a reflow solder on a printed circuit board or the like, and is applied to a power supply circuit of an electronic device such as a mobile phone or a hard disk device. For example, it is preferably used at a switching frequency of 250 KHz to 2 MHz.

  As shown in FIG. 1, the coil component 1 mainly includes a drum core 2, an outer peripheral core 3, a first electrode 4, and a second electrode 5.

  As shown in FIG. 2B, the drum core 2 has a substantially cylindrical core part 23 and a first flange part coaxially provided at both axial ends of the core part 23 with a magnetic material as a base material. 21 and the second flange 22. Each of the first flange portion 21 and the second flange portion 22 has a disk shape having substantially the same shape, and a first side surface 21A and a second side surface 22A, which are flange-facing surfaces, are defined at outer peripheral positions of the disk. ing. Further, the first flange portion 21 is defined with a first outer surface 21B and a first inner surface 21C extending in a direction orthogonal to the first side surface 21A, and the second flange portion 22 is similarly formed with a second outer surface 22B and a second inner surface 21C. An inner surface 22C is defined. A winding 11 is wound around the core part 23. The first side surface 21A and the second side surface 22A are covered with a coating layer 8A and a coating layer 8B (FIG. 2B) made of nonmagnetic resin, respectively.

  The winding 11 is configured by applying an insulating urethane coating to a copper wire, and both ends thereof are connection points that are connected to the first electrode 4 and the second electrode 5 (FIG. 1).

  As shown in FIG. 1, the outer peripheral core 3 is composed of a first divided core 6 and a second divided core 7. Since the first divided core 6 and the second divided core 7 have the same shape, only the first divided core 6 will be described below unless otherwise specified.

  Like the drum core 2, the first split core 6 is made of a magnetic material as a base material, and has an inner curved surface 6A that is an outer peripheral core facing surface facing the first side surface 21A and the second side surface 22A. The inner curved surface 6A is formed in an arc shape. Further, the length of the inner curved surface 6A in the arc direction is configured to be slightly more than ¼ of the circumferential length of the first side surface 21A and the second side surface 22A.

  Moreover, as shown in FIG. 1, the 1st projection part 61 and the 2nd projection part 62 are each provided in the position of the both ends vicinity of the circular direction of the inner curved surface 6A. The first projecting portion 61 and the second projecting portion 62 each extend in a direction coinciding with the axial direction of the drum core 2, and are in contact with the covering layer 8A and the covering layer 8B on the first side surface 21A and the second side surface 22A, respectively. . By the first protrusion 61 and the second protrusion 62, a gap is formed between the inner curved surface 6A of the first split core 6 and the covering layer 8A and the covering layer 8B. As shown in FIG. 2 (a), the first divided core 6 includes adhesives 9A and 9B made of a nonmagnetic resin injected into the gap between the inner curved surface 6A and the coating layer 8A and the coating layer 8B (see FIG. 2). It is bonded to the drum core 2 by 1). Similarly, the second divided core 7 is bonded to the drum core 2 by the adhesives 9C and 9D (FIG. 1) made of nonmagnetic resin injected into the gap between the inner curved surface 7A and the coating layer 8A and the coating layer 8B. Yes.

  As shown in FIG. 1, FIG. 2 (a), and FIG. 2 (b), the outer surface 6 </ b> B serving as the outer peripheral position of the first split core 6 in a state where the first split core 6 is disposed on the outer periphery of the drum core 2. The first electrode 4 is fixed by an adhesive 9E. The first electrode 4 extends to the lower surface 6C of the first split core 6 and the second outer surface 22B of the second flange portion 22, that is, the base mounting surface, and the coil component 1 is surface-mounted on a substrate (not shown). In this case, it is electrically connected to the electrode on the substrate. A connecting portion 10A is provided at the end of the first electrode 4 so as to be disposed between the first divided core 6 and the second divided core 7, and the winding 11 is connected to the connecting portion 10A. One end is arranged and connected. The same second electrode 5 is also fixed to the outer side surface 7B by the adhesive 9F on the second divided core 7, and extends to the lower surface 7C of the second divided core 7 and the second outer surface 22B of the flange portion 22, that is, the substrate mounting surface. It is installed. Further, a connecting portion 10B is provided at the end of the second electrode 5 so as to be disposed between the first divided core 6 and the second divided core 7, and a winding is provided around the connecting portion 10B. The other end of 11 is arranged and connected.

  Next, the manufacturing method of the coil component 1 by this Embodiment is demonstrated. First, the drum core 2, the outer core 3, the first electrode 4, the second electrode 5, and the winding 11 are prepared. Next, the first side surface 21A of the first flange portion 21 and the second side surface 22A of the second flange portion 22 are coated with a nonmagnetic resin. This covering step will be described with reference to FIGS. 3 (a) to 3 (f). As shown in FIG. 3A, the drum core 2 is held so that the first outer surface 21B of the first flange 22 faces the resin liquid tank W filled with the nonmagnetic resin liquid. Next, as shown in FIG. 3B, the first brim part 22 is immersed in the resin liquid tank W to a depth at which the resin does not enter the first inner surface 21 </ b> C and the core part 23 of the first brim part 22.

  As shown in FIG.3 (c), the immersed drum core 2 is pulled up. The resin is applied to the portion of the first side surface 21A where the resin R is not attached (the portion that has not been immersed in the resin liquid tank W), and as shown in FIG. Rotate. Thereby, resin R adhering to the 1st collar part 22 becomes substantially uniform thickness. The process shown in FIGS. 3A to 3D corresponds to the coating process. Next, it is confirmed that the resin R is attached to the entire surface of the first side surface 21A, and the resin R attached to the first side surface 21A and the first outer surface 21B is cured (curing step). The resin R adhering to the first outer surface 21B of the first flange portion 21 shown in FIG. 3 (e) is removed by grinding or the like (for example, shaving with a blade or polishing). As described above, the coating layer 8A is formed on the first outer surface 21A as shown in FIG.

  Next, the coating layer 8B is formed on the second side surface 22A of the second flange portion 22 in the same manner as the coating layer 8A is formed on the first side surface 21A. And the coil | winding 11 is wound around the core part 23 of the drum core 2 by which coating layer 8A, 8B was formed in the 1st side surface 21A and the 2nd side surface 22A.

  Next, the first divided core 6 and the first electrode 4, and the second divided core 7 and the second electrode 5 are bonded by adhesives 9E and 9F, respectively. The first side surface 21A, the second side surface 22A, and the inner curved surface 7A are covered with the coating layer 8A so that the first side surface 21A, the second side surface 22A and the inner curved surface 6A are opposed to each other through the coating layer 8A and the coating layer 8B. The drum core 2 is combined with the first divided core 6 and the second divided core 7 so as to face each other via the coating layer 8B (combining step). Specifically, the first protrusion 61 and the second protrusion 62 provided on the inner curved surface 6A, and the first protrusion 71 and the second protrusion 72 provided on the inner curved surface 7A are respectively connected to the covering layer 8A and It contacts with the coating layer 8B.

  Next, adhesives 9A, 9B, 9C made of non-magnetic resin are formed in the gap between the inner curved surface 6A and the coating layer 8A and the coating layer 8B and the gap between the inner curved surface 7A and the coating layer 8A and the coating layer 8B. 9D is injected and cured. Next, both ends of the winding 11 are connected and welded to the connecting portions 10A and 10B, respectively. The coil component 1 is completed through the above steps.

  According to the manufacturing method of the coil component 1 described above, after the coating layers 8A and 8B made of nonmagnetic resin are formed on the first side surface 21A and the second side surface 22A of the drum core 2, the drum core 2 and the first divided core 6 and The second divided core 7 was combined. Therefore, the first protrusions 61 and 71 and the second protrusions 62 and 72 can be prevented from coming into direct contact with the drum core 2, and the first side surface 21A and the second side surface 22A and the inner curved surfaces 6A and 7A A magnetic gap can be reliably formed between the two. Accordingly, it is possible to provide the coil component 1 that is quantitatively stable with little change in inductance value even in a minute current region. Furthermore, it is possible to provide the coil component 1 having good direct current superposition characteristics in which the inductance value does not rapidly decrease even in a high current region.

  In the above manufacturing method, the coating layer 8A is formed on the first side surface 21A, and then the coating layer 8B is formed on the second side surface 22A. Therefore, since the process of forming the coating layer 8A and the process of forming the coating layer 8B are performed separately, the coating layers 8A and 8B can be reliably formed on the first side surface 21A and the second side surface 22A.

  In addition, the manufacturing method of the coil component of this invention is not limited to embodiment mentioned above, A various deformation | transformation and improvement are possible in the range described in the claim. For example, the coil component 1 manufactured by the above-described coil component manufacturing method is provided with the first projecting portions 61 and 71 and the second projecting portions 62 and 72 on the first divided core 6 and the second divided core 7. However, like the coil component 101 in FIG. 4, the first split core 106 and the second split core 107 may not be provided with the first protrusion and the second protrusion. Even in this configuration, the coating layer 8A can prevent the first divided core 106 and the second divided core 107 from directly contacting the drum core 2, and the coating layer 8A having a substantially uniform thickness The gap between the first and second divided cores 106 and 107 and the drum core 2 can be kept constant. In the above embodiment, the coating layers 8A and 8B are formed on the first side surface 21A and the second side surface 22A of the drum core 2, but the inner curved surface 6A of the first divided core 6 and the inner surfaces of the second divided core 7 A coating layer made of nonmagnetic resin may be formed on the curved surface 7A. Also with this configuration, it is possible to prevent the first divided core 6 and the second divided core 7 from coming into direct contact with the drum core 2, and the same effects as in the above embodiment can be obtained.

It is a perspective view of the coil component manufactured by the manufacturing method of the coil component in embodiment of this invention. It is a cross-sectional view of the coil component shown in FIG. It is sectional drawing along the IIb-IIb line | wire of Fig.2 (a). In the step of coating the first side surface of the first collar part and the second side surface of the second collar part of the coil component manufacturing method according to the embodiment of the present invention with a non-magnetic resin, The figure which shows the state which made the 1st outer surface of the 1st collar part oppose. The figure which shows the state which immersed the 1st collar part of the drum core in the resin liquid tank after Fig.3 (a). The figure which shows the state which pulled up the drum core after FIG.3 (b). The figure which shows the state which rotated the drum core centering on the axis | shaft of a core part after FIG.3 (c). The figure which shows the state which hardened the resin adhering to the 1st side surface and 1st outer surface of a drum core after FIG.3 (d). The figure which shows the state which removed the resin adhering to the 1st outer surface of a 1st collar part by grinding etc. after FIG.3 (e). The figure which shows the modification of the coil components manufactured by the manufacturing method of the coil components in this Embodiment.

Explanation of symbols

1, 101 Coil parts 2 Drum core 3 Outer core 4 First electrode 5 Second electrode 6 First divided core 6A Inner curved surface 7 Second divided core 7A Inner curved surface 8A Coating layer 8B Coating layer 11 Winding 21 First flange 21A First One side 22 Second flange 22A Second side 23 Core part

Claims (2)

A drum core having a columnar core part and a pair of flanges provided at both ends of the core part; a winding wound around the core part; and an outer core covering an outer peripheral part of the drum core; An electrode provided on at least one of the drum core or the outer peripheral core and connected to an end of the winding;
The outer peripheral core is defined with an outer peripheral core facing surface that faces the outer peripheral portion of the pair of flanges, and the pair of flanges is defined with a flange facing surface that faces the outer core facing surface, respectively. A method of manufacturing a coil component,
A coating step of coating a nonmagnetic resin on at least one of the flange facing surface and the outer core facing surface;
A curing step for curing the resin;
A manufacturing method of a coil component comprising: a combination step of combining the drum core and the outer peripheral core so that the outer peripheral core facing surface and the flange facing surface are opposed to each other through the resin. . In the coating step, a first coating step of coating one of the pair of flanges on the flange-facing surface of the pair and a second coating of the resin on the other flange-facing surface of the pair of flanges. 2 coating process,
The curing step includes a first curing step for curing the resin coated on the one flange-facing surface, and a second curing step for curing the resin coated on the other collar-facing surface. Consists of
The method of manufacturing a coil component according to claim 1, wherein the first curing step is performed after the first coating step, and then the second curing step is performed after the second coating step. .

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