JP2011165696A - Method of manufacturing winding coil component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress flow-out of molding resin during drying and curing steps to prevent contamination of an external electrode due to the flow of a resin ingredient reaching a surface of the external electrode, so as to surely and efficiently make a reliable winding type coil component. <P>SOLUTION: In manufacturing a winding coil component including the molding resin provided to cover winding wound around a core of a magnetic core having the core, a pair of flanges provided at both ends of the core and the external electrode provided on an outer side face of at least one of the flanges, a resin composition which contains epoxy resin with a molecular weight of 1,850 or larger, a filler and a solvent and becomes the molding resin after curing is applied to between the pair of flanges to cover the winding wound around the core. The resin composition is dried and cured, thereby obtaining the winding type coil component having the winding molded of the molding resin. Steps of drying and curing the resin composition take place in a temperature range of 100-180°C. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a wound coil component, and more specifically, a winding of a magnetic core having a winding core and a pair of flanges disposed on both ends thereof, wound around the winding core. It is related with the manufacturing method of the coil component provided with mold resin (outer layer resin) with which it filled between a pair of collar parts so that it might cover.

  For example, as shown in FIG. 4, a magnetic core 53 having a winding core portion 51 and a pair of flange portions 52 a and 52 b disposed on both ends thereof, A winding 54 wound around the core 51, a mold resin 55 filled between the pair of flanges 52a and 52b so as to cover the winding 54 wound around the core 51, and a pair of One end and the other end of the winding 54 are disposed on the surface (outer surface) opposite to the surface facing the upper flange 52b of the lower flange 52a of the flanges 52a and 52b. There is a chip-type winding coil component including a pair of external electrodes 56a and 56b to which parts are electrically connected.

  And as a resin composition for mold resin used in such a wound coil component, for example, (A) epoxy resin, (B) silica particles, (C) acid anhydride, and (D) curing acceleration An epoxy resin composition containing 30 to 85% by mass of silica particles having an average particle size of 10 to 30 μm as the silica particles (B) as an essential component (epoxy resin composition for mold coil impregnation) And a molded coil device using this resin composition has been proposed (see Patent Document 1).

  The resin composition of this Patent Document 1 is excellent in impregnation into a coil, and the cured product has high mechanical strength and high dielectric breakdown voltage in an energized state, and is excellent in insulation reliability. By using it as a resin for molding, it is said that a molded coil device excellent in mechanical strength and insulation reliability can be manufactured at low cost.

However, when this resin composition is used, when it is necessary to apply a considerable amount of the resin composition in order to avoid the exposure of the winding, the step of heating and drying and curing the resin composition Thus, there is a problem that the resin component flows out and goes around to the outer surface of the flange, contaminates the surface of the external electrode, and lowers the connection reliability (mounting reliability).
Moreover, when filling with fillers, such as a silica particle, in a high ratio, in order to improve the fluidity | liquidity of a resin composition, a solvent may be included. In such a case, the problem of contamination of the external electrode is likely to occur.

JP 2008-195782 A

  This invention solves the said subject, suppresses the resin for the mold used in a manufacturing process flowing out at the process of drying and hardening, and an external electrode by which a resin component wraps around to the surface of an external electrode It is an object of the present invention to provide a method for manufacturing a wire-wound coil component that can reliably and efficiently manufacture a highly reliable wire-wound coil component.

In order to solve the above problems, a method for manufacturing a wound coil component according to the present invention includes:
A magnetic core having a winding core and a pair of flanges disposed on both ends thereof;
A winding wound around the core portion of the magnetic core;
One of the pair of flanges is disposed on a surface opposite to the surface facing the other flange, and one end and the other end of the winding are electrically connected. A pair of external electrodes,
A method for manufacturing a wound coil component comprising: a mold resin filled between the pair of flanges so as to cover the winding wound around the winding core part,
The pair of eaves parts covering a winding wound around the core part with a resin composition containing an epoxy resin having a molecular weight of 1850 or more, a filler, and a solvent, which becomes the mold resin after curing. A process of applying between,
And a step of drying and curing the resin composition applied between the pair of collars.

  Moreover, in the manufacturing method of the winding type coil components of this invention, it is desirable that the process of drying and hardening the said resin composition is implemented in the temperature range of 100 degreeC or more and 180 degrees C or less.

  Moreover, it is desirable that the step of drying and curing the resin composition includes a drying step of drying at a predetermined temperature and a curing step performed at a temperature higher than the drying step.

  In the method for manufacturing a wound coil component of the present invention, a resin composition that contains an epoxy resin having a molecular weight of 1850 or more, a filler, and a solvent and becomes a mold resin after curing is wound around a core part. Since it is applied between the pair of flanges of the mold resin so as to cover the windings and dried and cured, it is possible to prevent the resin from flowing out and prevent the surface of the external electrode from being contaminated. Thus, a highly reliable wire-wound coil component can be manufactured reliably and efficiently.

  That is, since an epoxy resin having a molecular weight of 1850 or higher has a high softening point, the fluidity when heated, dried and cured is small, and wraparound due to capillary action is unlikely to occur. Therefore, by using such an epoxy resin as a base resin, it is possible to suppress and prevent the resin component from wrapping around, and to reliably prevent the surface of the external electrode from being contaminated by the resin. While maintaining high, there is no contamination of the surface of the external electrode, and a wire-wound coil component having excellent mounting reliability can be reliably manufactured.

  In addition, although there is no special restriction | limiting in the kind of epoxy resin which comprises the resin composition used in this invention, Bisphenol A type epoxy resin is mentioned as an example of a suitable epoxy resin.

  In addition, there are no particular restrictions on the type of filler constituting the resin composition used in the present invention, and various types are used for the purpose of controlling fillability, fluidity, etc., or improving insulation. Can be used. Typical fillers include magnetic particles such as ferrite particles and insulator ceramic particles such as silica particles. Moreover, there is no special restriction | limiting also about the compounding ratio of the filler in a resin composition, It is possible to set it as a various ratio according to a use etc.

  Moreover, there is no special restriction | limiting also about the kind of solvent contained in a resin composition, For example, various solvents including a dipropylene glycol methyl ether acetate can be used in various ratios.

  Further, in the present invention, there is no special restriction on the method of applying (applying) the resin composition. For example, the surface of the external electrode is closely attached to a support such as an adhesive tape, and the coiled coil component. Dispensing in the resin composition in such a manner that at least the surface on which the external electrode is formed is not dipped, holding the element and supplying the resin composition from the dispenser in that state and applying it so as to cover the winding By doing so, various methods such as a dipping coating method of coating the resin composition so as to cover the windings can be used.

  Further, by carrying out the step of drying and curing the resin composition in a temperature range of 100 ° C. or higher and 180 ° C. or lower, the flow of the resin when drying and curing the resin composition is more reliably suppressed, It becomes possible to prevent the resin component from wrapping around the external electrode, and the present invention can be made more effective.

  Also, when drying and curing the resin composition, after performing the drying process at a predetermined temperature lower than the heat treatment temperature in the curing process, the temperature is further increased and the curing process is performed at a temperature higher than the drying process. By doing so, it becomes possible to cure the resin composition while suppressing the flow of the resin composition, and the present invention can be further effectively realized.

  In addition, in the manufacturing method of the winding type coil components of this invention, while implementing a drying process in the range which does not become 30 degreeC or more higher than the softening temperature of an epoxy resin, fully suppressing the flow of a resin composition. It becomes possible to dry the solvent, and it is possible to reliably suppress and prevent the resin component from reaching the surface of the external electrode even when the curing step is performed by further raising the temperature thereafter. .

It is front sectional drawing which shows the winding coil component element of the stage before arrange | positioning mold resin prepared in the Example of this invention. In the Example of this invention, it is a figure which shows the method of apply | coating and filling a resin composition between a pair of collar parts of a magnetic core so that the coil | winding wound by the winding core part may be covered. It is front sectional drawing which shows the winding coil components manufactured by the method concerning the Example of this invention. It is front sectional drawing which shows the conventional winding coil components provided with mold resin.

  Embodiments of the present invention will be described below to describe the features of the present invention in more detail.

<Example 1>
[1] Production of resin composition First, the following raw materials were weighed and mixed to produce a resin composition.
The viscosity of this resin composition was 23 Pa · s.
(a) Epoxy resin (bisphenol A type epoxy resin having a molecular weight of 1850 and a softening point of 97 ° C.) 349 g
(b) Curing agent (phenol resin) 40 g
(c) Solvent (dipropylene glycol methyl ether acetate) 761 g
(d) 3617 g filler (ferrite particles)
(e) 3.3 g of accelerator (imidazole accelerator)

[2] Production of Winding Coil Parts with Mold Resin In this example, as shown in FIG. 1, a winding core part 1 and both ends thereof as winding coil part elements to which a resin composition is applied. A magnetic core 3 having a pair of flanges 2a and 2b disposed on the side, a winding 4 wound around the core 1 of the magnetic core 3 and having an insulating coating on the surface, and a winding 4 A winding coil component element (winding coil component before the molding resin is disposed) A1 provided with external electrodes 6a and 6b to which both ends of are electrically connected was prepared.

  In addition, external electrode 6a, 6b is on the surface on the opposite side to the surface which opposes the other collar part 2b of one collar part 2a which opposes the other collar part 2b among a pair of collar parts 2a, 2b. It is arranged. One end of the winding 4 is connected to one external electrode 6a, and the other end is electrically connected to the other external electrode 6b.

  Then, as shown in FIG. 2, an adhesive tape (holding member) configured to be conveyed in a predetermined direction (in the direction of arrow X) in such a posture that the main surface is substantially vertical and the longitudinal direction is substantially horizontal. ) 10 is adhesively held on the surface on which the external electrodes 6a and 6b are formed of the flange portion 2a of the wound coil component element A1.

  In this state, between the pair of flange portions 2a and 2b of the magnetic core 3 so as to cover the winding 4 wound around the winding core portion 1 of the winding coil component element A1, as described above. The produced resin composition 5a was applied and filled using the dispenser applicator 11.

  In addition, when applying and filling the resin composition 5a, the resin composition is diluted until the viscosity becomes 3 Pa · s by adding the same solvent (dipropylene glycol methyl ether acetate) as the solvent used for preparing the raw material. Used.

  Then, the wound coil part element A1 filled with the resin composition 5a between the flanges 2a and 2b is dried by heating to 100 ° C. and holding for 0.5 h, and at least most of the solvent is volatilized and removed. Then, the temperature was further raised and the resin composition 5a was cured by holding at 150 ° C. for 3 hours. As a result, as shown in FIG. 3, the coiled coil component A having a structure in which the coil 4 wound around the core 1 of the coiled coil component element A <b> 1 (FIG. 1) is molded with the mold resin 5. Got. Note that, in FIG. 3, the same reference numerals as those in FIG. 1 denote the same parts.

Then, for the wound-type coil component produced in this way, the surface of the external electrode is observed to confirm the presence or absence of contamination due to the wraparound of the mold resin, and the number (total number of samples) of the wound-type coil components used for the observation The defect rate was calculated from the relationship between the number of wound coil components that were contaminated (number of contamination defects). In addition, the defective rate was calculated | required by the following formula.
Defective rate (%) = (number of samples with defective contamination / total number of samples) × 100

<Example 2>
As the epoxy resin (a) constituting the resin composition of Example 1, a bisphenol A type epoxy resin (softening point 144 ° C.) having a molecular weight of 5700 was used, and its blending amount was 375 g. A resin composition was prepared in the same manner as in Example 1 except that the same phenol resin was used as the curing agent (b) constituting the resin composition of Example 1 and the blending amount was 14 g. The viscosity of the resin composition in Example 2 was 66 Pa · s.
And the winding type coil components were produced by the same method as the case of Example 1 using this resin composition, and it evaluated by the same method.

<Comparative Example 1>
As the epoxy resin of (a) constituting the resin composition of Example 1, a bisphenol A type epoxy resin having a molecular weight of 1000 (softening point: 64 ° C.) was used, and its blending amount was 318 g. A resin composition was prepared in the same manner as in Example 1 except that the same phenol resin was used as the curing agent (b) constituting the resin composition of Example 1 and the blending amount was 70 g. The viscosity of the resin composition in Comparative Example 1 was 20 Pa · s.
And the winding type coil components were produced by the same method as the case of Example 1 using this resin composition, and it evaluated by the same method.

[Comparative Example 2]
As the epoxy resin (a) constituting the resin composition of Example 1 above, a bisphenol A type epoxy resin (softening point 67 ° C.) having a molecular weight of 1200 was used, and its blending amount was 334 g. A resin composition was prepared in the same manner as in Example 1 except that the same phenol resin was used as the curing agent (b) constituting the resin composition of Example 1 and the blending amount was 54 g. The viscosity of the resin composition in Comparative Example 2 was 20 Pa · s.
And the winding type coil components were produced by the same method as the case of Example 1 using this resin composition, and it evaluated by the same method.

[Comparative Example 3]
As the epoxy resin (a) constituting the resin composition of Example 1, a bisphenol A type epoxy resin having a molecular weight of 1500 (softening point 82 ° C.) was used, and its blending amount was set to 341 g. A resin composition was prepared in the same manner as in Example 1 except that the same phenol resin was used as the curing agent (b) constituting the resin composition of Example 1 and the blending amount was 47 g. The viscosity of the resin composition in Comparative Example 3 was 22 Pa · s.
And the winding type coil components were produced by the same method as the case of Example 1 using this resin composition, and it evaluated by the same method.

[Evaluation]
Table 1 shows the evaluation results of the winding type coil parts of Examples 1 and 2 and the winding type coil parts of Comparative Examples 1 to 3 manufactured as described above.

  As shown in Table 1, Example 1 using an epoxy resin (bisphenol A type epoxy resin) having a molecular weight of 1850 and a softening point of 97 ° C. as an epoxy resin, and an epoxy resin having a molecular weight of 5700 and a softening point of 144 In the case of the wound-type coil component of Example 2 using an epoxy resin at 0 ° C., the rate of occurrence (defect rate) where the surface of the external electrode is contaminated by the wrapping resin is 1.5% (Example 1) Further, it was confirmed that a highly reliable wire-wound coil component can be efficiently manufactured with a low 1.4% (Example 2).

  On the other hand, as an epoxy resin, Comparative Example 1 using an epoxy resin (bisphenol A type epoxy resin) having a molecular weight of 1000 and a softening point of 64 ° C., comparison using an epoxy resin having a molecular weight of 1200 and a softening point of 67 ° C. In the case of the wound type coil component of Example 2 and Comparative Example 3 using an epoxy resin having a molecular weight of 1500 and a softening point of 82 ° C., the ratio of occurrence of defects in which the surface of the external electrode is contaminated by the wraparound resin ( The defect rate was as high as 7.0% (Comparative Example 1), 5.6% (Comparative Example 2), and 3.4% (Comparative Example 3), confirming that the reliability was low.

  In addition, when the requirements of the present invention are satisfied, the incidence of defects due to contamination of the surface of the external electrode due to the wraparound of the resin is reduced because the molecular weight of the epoxy resin constituting the resin composition is 1850 or more. Since an epoxy resin having a high softening point is used, it is difficult for the resin component to flow in the heat treatment step for drying and curing the applied resin composition, and in the surface of the external electrode, that is, in the above embodiment, This is because the resin is less likely to enter the space formed by the adhesive tape (holding member) 10 and the surface on which the external electrodes 6a and 6b of the flange 2a of the magnetic core 3 are formed.

  From the above results, according to the method for manufacturing a wound-type coil component of the present invention, the resin composition 5a filled to cover the winding 4 between the pair of flanges 2a, 2b of the magnetic core 3 It was confirmed that a highly reliable coiled coil component A can be efficiently manufactured by preventing it from flowing into the surface of the external electrodes 6a and 6b through the heat treatment process for drying and curing.

  In the above embodiment, ferrite particles are used as the filler constituting the resin composition, and dipropylene glycol methyl ether acetate is used as the solvent. However, other types of fillers and solvents can be used.

  Moreover, in the said Example, the drying / hardening process of a resin composition is carried out by the drying process implemented by hold | maintaining a resin composition at 100 degreeC for 0.5 h, and also raises temperature after that, at 150 degreeC. And a curing step for curing the resin composition by holding for 3 hours, a two-step heat treatment step is performed. The temperature conditions at each step are the type of epoxy resin constituting the resin composition and the resin composition. It is desirable to determine in consideration of the specific composition and the like.

  Further, in some cases, the drying / curing heat treatment step may be performed at a predetermined constant temperature (that is, drying and curing are performed by one-step heat treatment).

  The present invention is not limited to the above-described examples in other points as well. The specific composition of the resin composition, the configuration of the magnetic core constituting the wound coil component, the arrangement of the external electrodes, Various applications and modifications can be made within the scope of the invention with respect to the coating method of the resin composition.

DESCRIPTION OF SYMBOLS 1 Core part 2a, 2b Eaves part 3 Magnetic core 4 Winding 5 Mold resin 5a Resin composition 6a, 6b External electrode 10 Adhesive tape (holding member)
11 Dispenser A1 Winding coil component element A Winding coil component

Claims (3)

A magnetic core having a winding core and a pair of flanges disposed on both ends thereof;
A winding wound around the core portion of the magnetic core;
One of the pair of flanges is disposed on a surface opposite to the surface facing the other flange, and one end and the other end of the winding are electrically connected. A pair of external electrodes,
A method for manufacturing a wound coil component comprising: a mold resin filled between the pair of flanges so as to cover the winding wound around the winding core part,
The pair of eaves parts covering a winding wound around the core part with a resin composition containing an epoxy resin having a molecular weight of 1850 or more, a filler, and a solvent, which becomes the mold resin after curing. A process of applying between,
A step of drying and curing the resin composition applied between the pair of collars. A method of manufacturing a wound coil component, comprising:   The method for manufacturing a wound coil component according to claim 1, wherein the step of drying and curing the resin composition is performed in a temperature range of 100 ° C or higher and 180 ° C or lower.   The step of drying and curing the resin composition includes a drying step of drying at a predetermined temperature and a curing step performed at a temperature higher than the drying step. 2. A method for manufacturing a wound coil component according to 2.

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