JP2003173917A - Coil component and method of manufacturing the same - Google Patents

Abstract

(57) [Problem] To provide a coil for a switching power supply used in various electronic devices, and to improve the space factor of the coil and secure external safety, and a highly productive coil component. The purpose is to provide a manufacturing method at low cost. SOLUTION: The closed magnetic path core 5 includes a closed magnetic path core 5 formed by combining two divided magnetic cores 4 having a middle leg 1, an outer leg 2, and a connecting leg 3, and an air core coil 6. The resin forming the filling portion 7 and the exterior portion 8 is made the same, and the first coil forming step of winding the air-core coil, the second step of incorporating the closed magnetic circuit core 5, and the closed magnetic circuit core 5 are performed. And a third exterior part forming step of injection molding while pressing and supporting with a support pin 14 from above and below.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil component used in various electronic devices and the like and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, as information and communication infrastructure networks are large and progressing, an increase in power consumption has become a social problem. In particular, with regard to the switching power supply that constitutes the power supply unit, development competition is intensifying in line with miniaturization, high efficiency, and cost reduction to meet social needs. Inductor components such as transformers and coils, which are key parts to meet the needs for power supply development, are strongly required to be extremely compact, have high performance (low loss), and be even lower in cost. In particular, various types of resin-filled transformers and coil components have been proposed as means for achieving miniaturization needs.

As a conventional coil and transformer filled with resin, Japanese Utility Model Laid-Open No. 4-105523 (Practical model registration 2
No. 551237), in which an air-core coil is laminated on a bobbin, a magnetic core is incorporated, and then the whole is molded and covered with an insulating resin, which is wound around the bobbin as in Japanese Utility Model Laid-Open No. 5-14489. After winding, the coil part is molded with an insulating resin, and a closed magnetic circuit magnetic core is incorporated from the horizontal direction. An air-core coil is laminated on a bobbin as in JP-A-11-54335, and then the coil part is insulated. There is also one in which a magnetic core is incorporated after molding with resin. JP-A-6-
As shown in Japanese Patent Publication No. 89819, after winding a coil around a tubular bobbin, the coil portion is molded with an insulating resin and a closed magnetic circuit magnetic core is incorporated from above or below, or after the coil is wound around the bobbin. There is a configuration in which the coil portion is first molded with an insulating resin, the closed magnetic circuit magnetic cores are assembled from above and below to complete the transformer, and then the second molding is performed and the entire transformer is covered with the insulating resin. All of the above-mentioned conventional examples have the common point that a coil is mounted on the bobbin, but either the coil part is molded, or the coil part is not molded and the magnetic core is assembled and then the whole part is molded. The partial molding and the whole molding were performed twice. Furthermore, after molding the air-core coil with an insulating resin without using a bobbin as in Japanese Patent Application Laid-Open Nos. 10-149931 and 11-97259, which have been filed by our company,
Some also incorporate a closed magnetic circuit core.

[0004]

However, in the above-mentioned conventional transformer and coil, since the bobbin is generally used to maintain the insulation between the magnetic core, the coil portion and the magnetic core, the coil is as thick as the bobbin. Since the space factor is deteriorated and the conductor resistance is increased, the loss is increased and the number of parts is also increased. Also, in order to ensure the insulation between the coil and the magnetic core even when the bobbin is not used,
Since the magnetic core was incorporated after molding only the coil portion with the insulating resin, the safety from the outside was not sufficient and had a problem. Further, there is a conventional example in which the coil portion and the entire exterior portion are molded, but the molding process is performed twice, and the molding step is performed twice, which leaves a problem in terms of productivity.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and provides a coil component having a high productivity, in which the space factor of the coil is improved and the safety from the outside can be secured, and a method for manufacturing the same, at low cost. Has an aim.

[0006]

In order to achieve the above object, the present invention has the following constitution.

The invention according to claim 1 of the present invention includes two split magnetic cores having a middle leg, an outer leg facing the middle leg, and a connecting leg connecting the middle leg and the outer leg. A closed magnetic circuit magnetic core formed by combining the core and an air-core coil inserted into the middle leg.The closed magnetic circuit magnetic core is filled with resin to form a filling portion, and the closed magnetic circuit magnetic core is covered with resin. The exterior part is formed by using the same resin used to form the filling part and the exterior part, and the coil is formed without using the bobbin, so the number of parts can be reduced and the space factor of the coil can be reduced. Also improves. Further, since the gap between the air-core coil and the closed magnetic circuit core is filled with resin, insulation can be maintained even if the bobbin is eliminated. Furthermore, since the exterior part of the closed magnetic circuit core is covered with the insulating resin, the insulation from the external parts is maintained and the safety is increased.

The invention described in claim 2 of the present invention is, in the invention described in claim 1, an air-core coil in which rectangular wires are wound adjacent to each other in the longitudinal direction, and the wide side of the rectangular wires is provided. Since the coil is wound in the horizontal direction, the coil space factor is improved relative to the window area of the closed magnetic circuit core, and the shape is easily maintained.

According to a third aspect of the present invention, in the invention according to the first aspect, the closed magnetic circuit magnetic core is a dust core, and the dust core itself has a magnetic gap to some extent. Since it is a hardened material, deterioration of magnetic characteristics (decrease in inductance) can be minimized even when a magnetic gap is created due to cracking of the magnetic core.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the material of the filling resin is a liquid crystal polymer made of an aromatic polyester resin, which has a high heat resistance. Since it is a resin of No. 1, it is possible to provide surface mount reflow compatible and high heat resistant insulation that can withstand continuous use of F type (155 ° C.) or more.

According to a fifth aspect of the present invention, in the invention according to any one of the first to third aspects, the material of the filling resin is an epoxy type, and the penetrability and adhesion are very high. Since it is good, the moisture resistance performance can be improved. Also,
By using a low-pressure molding method such as casting or transfer molding, the stress on the magnetic core can be relaxed, and the reliability of the product is improved.

According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, at least one magnetic core exposed portion which is not covered with resin is provided in the exterior portion. By using this exposed portion, the withstand voltage of the coil and the magnetic core can be measured.

According to a seventh aspect of the present invention, in the invention according to the sixth aspect, the exposed portion of the magnetic core is provided on the upper and lower surfaces of the connecting leg of the closed magnetic circuit magnetic core, and this portion is formed at the time of molding. Since the support pin of the magnetic core retainer can be set by utilizing it, the magnetic core can be pressed from the up and down direction.

According to an eighth aspect of the present invention, in the invention according to any one of the first to fifth aspects, a recessed notch groove is provided on a side surface of an exterior portion which covers an outer leg portion of a closed magnetic circuit magnetic core. Since the supporting rods that regulate the position of the magnetic core can be inserted from above and below along the notch groove during molding, it is possible to prevent the horizontal deviation of the magnetic core from the center of the magnetic core toward the outer leg.

According to a ninth aspect of the present invention, in the invention according to any one of the first to fifth aspects, a recessed notch groove is provided on the side surface of the exterior portion covering the connecting leg of the closed magnetic circuit magnetic core. Since the support bar that regulates the position of the magnetic core can be inserted from above and below along the notch when molding, there is a horizontal magnetic core deviation from the center of the magnetic core to the direction without the outer leg. It can be prevented.

According to a tenth aspect of the present invention, in the invention according to the eighth or ninth aspect, at least a part of the notch groove is formed in a tapered shape, and the support rod is arranged from the vertical direction. When pressing, the magnetic core can be pressed from an oblique direction, so that not only horizontal but also vertical displacement can be prevented.

According to an eleventh aspect of the present invention, in the invention according to any one of the sixth to tenth aspects, a closed magnetic circuit magnetic core is formed on the abutting surfaces of the two divided magnetic cores without an adhesive. Therefore, it is possible to reduce variations in the magnetic gap dimension due to variations in the coating thickness of the adhesive. As a result, variations in characteristics (inductance) can be suppressed.

According to a twelfth aspect of the present invention, in the invention according to the first aspect, an insulative coil cap is provided between the closed magnetic circuit magnetic core and the air-core coil for regulating the position of the coil. Insulation between the closed magnetic circuit core and the air-core coil can be improved. Furthermore, the minimum required thickness that is regulated by safety standards can be ensured.

According to a thirteenth aspect of the present invention, in the invention according to the twelfth aspect, the material of the coil cap is the same as the resin forming the filling portion and the exterior portion, and the same resin material is used. Since it is configured, the conformability is improved, and the insulation between the magnetic core and the air-core coil is further improved.
Also, when applying for a standard for an insulation system, the content of the application can be simplified.

According to a fourteenth aspect of the present invention, in the invention according to the thirteenth aspect, a wavy corrugated portion is formed on the flange portion of the coil cap, and the corrugated portion has a spring property. Therefore, when the closed magnetic circuit magnetic core is incorporated, the length tolerance of the magnetic leg can be absorbed, and the stress on the magnetic core or the air-core coil can be relaxed. This makes it possible to prevent damage to the coil coating, cracking of the magnetic core, and the like.

A fifteenth aspect of the present invention is directed to a first coil forming step of winding an air-core coil and a second closed magnetic-path magnetic core incorporating a closed magnetic-path magnetic core by inserting a middle leg into the air-core coil. Forming step and forming the exterior part and the filling part at the same time by coating the closed magnetic circuit core and the coil with a filling resin
This is a method for manufacturing a coil component, which includes the step of forming the outer casing, and the bobbin is not attached and removed in the coil forming step. Moreover, since the gap between the outer core of the closed magnetic circuit magnetic core, the air-core coil and the magnetic core is filled at once, the resin filling process can be reduced.

According to a sixteenth aspect of the present invention, in the invention according to the fifteenth aspect, a rectangular wire is wound adjacently in the longitudinal direction in the first air-core coil forming step. Yes, it is easy to realize an air core coil that does not use a bobbin.

According to a seventeenth aspect of the present invention, in the method according to the fifteenth aspect of the invention, the third exterior portion forming step is an injection molding manufacturing method, and the molding time can be shortened. Therefore, productivity is improved.

According to an eighteenth aspect of the present invention, in the invention according to the seventeenth aspect, at least a part of the injection gate position of the filling resin is connected to the closed magnetic circuit magnetic core in the third exterior portion forming step. It is a manufacturing method provided on the ridges of the legs and the outer legs, and when the filling resin is injected, it is divided into those that spread on the connecting legs and those that spread on the outer legs.
Since both the connecting leg and the outer leg of the closed magnetic circuit core can be smoothly filled, the closed magnetic circuit core is not cracked even when the injection pressure at the time of injection is increased, and the filling portion is formed thin. be able to. Furthermore, since high-pressure molding can be performed, it is not necessary to specially introduce an expensive low-pressure molding device.

The invention according to claim 19 of the present invention is a claim
In the invention of item 18, the diameter of the injection gate is the exterior
The injection pressure is 800 kg /
cm ²2000 kg / cm or more²With the following
Since the manufacturing method is such that the release time is within 0.5 seconds,
We have provided various molding conditions, making it easy to select equipment
it can.

According to a twentieth aspect of the present invention, in the invention according to the fifteenth aspect or the seventeenth aspect, the connecting leg of the closed magnetic circuit magnetic core is pressed and supported by a support pin from above and below in the third exterior portion forming step. However, since the manufacturing method is performed by forming the exterior portion, the magnetic core can be pressed and held in the vertical direction, and the work process of fixing the magnetic core by bonding the closed magnetic circuit magnetic core can be reduced.

The invention according to claim 21 of the present invention is, in the invention according to claim 20, a manufacturing method in which at least one of the support pins is movably pressed and supported while being molded. When pressing and holding the top and bottom with the support pin, the fluctuation of the pressing force due to the tolerance of the magnetic core size can be absorbed by the elasticity of the movable pin, and as a result, the stress applied to the magnetic core can be relaxed, so that the core crack can be prevented. .

According to a twenty-second aspect of the present invention, in the invention according to the fifteenth aspect or the seventeenth aspect, the outer leg of the closed magnetic circuit magnetic core or the outer peripheral face of the connecting leg is outwardly moved in the third exterior portion forming step. Since it is a manufacturing method in which it is supported while being supported by a support rod, the positional deviation of the magnetic core in the horizontal direction can be regulated in the manufacturing process, the characteristic variation due to the positional deviation of the magnetic core can be reduced, and the process quality is stable. Is.

The invention according to claim 23 of the present invention is the invention according to any one of claims 20 to 22, wherein the step of adhering the abutting surface of the closed magnetic circuit magnetic core is eliminated in the second closed magnetic circuit magnetic core forming step. Therefore, it is possible to reduce the time-consuming work such as adhesive coating and curing that requires a long time at high temperature, and it is possible to significantly reduce the number of steps. Also, in terms of equipment, an adhesive coater, curing equipment, etc. are not required.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings.

(Embodiment 1) A first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a cross-sectional view of a coil component according to the first embodiment of the present invention, FIG. 2 is a perspective view for explaining a magnetic core incorporated state of the coil component, and FIG. 3 is before filling resin of the coil component. FIG. 4 is a perspective view of a completed product of the coil component, and FIG. 5 is a plan perspective view of the coil component. 1 to 5, 1 is a middle leg, 2 is an outer leg, 3 is a connecting leg, 4 is a split magnetic core, 5 is a closed magnetic circuit magnetic core, 6 is an air-core coil,
7 is a resin filling portion, 8 is an exterior portion, 9 is a rectangular wire, 10 is a drawing portion, 11 is an injection gate, 12 is a ridge side portion, 13 is a magnetic core exposed portion, 14 is a support pin, 15 is a notch groove, Reference numeral 16 indicates a support rod, and 17 indicates a tapered portion.

The coil component shown in FIG. 1 has two split magnetic cores 4 each having a middle leg 1, an outer leg 2 facing the middle leg 1, and a connecting leg 3 connecting the middle leg 1 and the outer leg 2 to each other. A closed magnetic circuit core 5 and an air-core coil 6 to be inserted into the middle leg 1, and the inside of the closed magnetic circuit core 5 is filled with resin to form a filling portion 7. The exterior part 8 is formed by being covered with the same resin as the filling part 7. Hereinafter, a specific description will be sequentially made with reference to FIGS.

As shown in FIG. 2, as a first step, an air-core coil 6 is manufactured in which rectangular wires 9 are vertically wound adjacent to each other and lead-out portions 10 are formed at both ends.

Next, as a second step, the divided magnetic cores 4 are assembled from above and below to form the closed magnetic circuit magnetic cores 5 as shown in the figure.
The coil component shown in FIG. 3 is completed. At this time, the magnetic core material forming the closed magnetic circuit magnetic core 5 is a powder magnetic core obtained by sintering low-temperature magnetic powder (generally around 800 ° C.) and hardening it, and high-temperature heat treatment (generally 1000). It has a lower magnetic permeability than magnetic materials such as ferrites (° C. or higher), but has a larger magnetic gap around ferrite than magnetic powder. No adhesive is used on the abutting surfaces of the two divided magnetic cores 4.

Next, as shown in FIG. 4, in a third step, the entire coil component is injection-molded with a liquid crystal polymer (LCP: aromatic polyester resin) which is a thermoplastic high heat-resistant insulating resin, and is then packaged. The part 8 is formed to complete the molded coil component.

At this time, it goes without saying that the gap between the air-core coil 6 and the closed magnetic circuit magnetic core 5 is simultaneously filled with the insulating resin to form the filling portion 7.

Further, as shown in FIGS. 1 and 4, the upper and lower surfaces of the exterior portion 8 of the coil component, that is, the upper and lower surfaces of the connecting portion 3 of the closed magnetic circuit magnetic core 5, have magnetic cores not covered with resin. In addition to providing the portion 13, a recessed cutout groove 15a is provided on the outer surface side 8a that covers the outer leg portion 2 of the closed magnetic circuit magnetic core 5, and cutout grooves 15b and 15c are provided on the outer surface 8b that covers the connecting leg 3. These notch grooves 15a, 15b, 15c are formed to have a tapered portion 17 at one end. these,
The exposed magnetic core portion 13 and the notch grooves 15a, 15b, 15c are used at the time of molding as shown in FIG. That is, as shown in FIG. 1, while pressing the magnetic core exposed portion 13 from above and below the connecting leg 3 of the closed magnetic circuit magnetic core 5 with the support pin 14, the notch groove 15a provided on the outer side surfaces 8a, 8b, 1
The outer legs 2 and the connecting legs 3 of the closed magnetic circuit magnetic core 5 along the outer peripheral surfaces 5b and 15c are resin-molded while being supported from the outside by the support rods 16. Further, the support pin 14 is molded while pressing and holding at least one of the upper and lower sides as a movable pin.

Further, as shown in FIG. 5, in the third exterior portion forming step, the injection gate 11 of the filling resin is the ridge side portion 12 between the connecting leg 3 of the closed magnetic circuit magnetic core 5 and the outer leg 2. Further, the diameter of the injection gate 11 is made larger than the side surface thickness of the exterior part 8 and the injection pressure is 800 kg / cm ² or more and 2000 k or more.
The injection time is 0.5 seconds or less while the g / cm ² or less is set.

As described above, FIG. 1 showing the first embodiment of the present invention.
According to the configuration of FIG. 5, since the coil is formed without using the bobbin, the number of parts can be reduced and the space factor of the coil can be improved. In addition, the air-core coil 6 and the closed magnetic circuit magnetic core 5
Since the gap is filled with resin, insulation is maintained even if the bobbin is eliminated. Further, since the outer casing 8 of the closed magnetic circuit magnetic core 5 is covered with the insulating resin, the insulation from the external parts is maintained and the safety is increased.

As the manufacturing method, the first coil forming step of winding the air-core coil 6 and the second closed magnetic-path magnetic core formation in which the middle leg portion 1 is inserted into the air-core coil 6 to incorporate the closed magnetic-path magnetic core 5 therein. And a closed exterior magnetic core 5 and the air-core coil 6 are covered with a filling resin to form an exterior portion 8 and a filling portion 7 at the same time. There is no need for desorption work. Also,
Since the gap between the exterior part 8 of the closed magnetic circuit magnetic core 5, the air-core coil 6 and the magnetic core 5 is filled at once, the resin filling process can be reduced.

Further, in the third exterior part forming step, the exterior part 8 is injection-molded while vertically supporting the connecting leg 3 of the closed magnetic circuit magnetic core 5 with the support pins 14 from above and below. Since the magnetic core can be pressed and held from the direction, it is possible to reduce the fixing work process such as adhesion of the closed magnetic circuit magnetic core 5. Moreover, since the molding time can be shortened, the productivity is improved.

As a result, the space factor of the coil is improved,
It is possible to provide a highly productive coil component capable of ensuring safety from the outside and a manufacturing method thereof at low cost.

Since the wide side of the rectangular wire 9 is wound in the horizontal direction, the bobbin is used because the coil space factor is improved with respect to the window area of the closed magnetic circuit core 5 and the shape is easily maintained. The air-core coil can be easily manufactured without doing so.

Further, although the closed magnetic circuit magnetic core 5 is a powder magnetic core, since the powder magnetic core itself is a material obtained by hardening magnetic powder having a certain magnetic gap, the magnetic core is cracked and the Even if a gap is created, deterioration of magnetic characteristics (decrease in inductance) can be minimized.

The material of the filling resin is liquid crystal polymer (L
CP: Aromatic polyester resin), which is a high heat resistant resin, so it is compatible with surface mounting reflow, F type (1
It is possible to provide high heat resistant insulation that can withstand continuous use at 55 ° C or higher.

Further, by providing the magnetic core exposed portion 13 not covered with the resin on the exterior portion 8, the magnetic core exposed portion 13 is provided.
Can be used to measure the withstand voltage of the coil and magnetic core.

Further, since the magnetic core exposed portion 13 is provided on the upper and lower surfaces of the connecting leg 3 of the closed magnetic circuit magnetic core 5, it is possible to make the support pin 14 of the magnetic core retainer by utilizing this portion during molding. The magnetic core can be pressed and held in the vertical direction. At this time,
If either one of the support pins 14 is used as a movable pin,
When the closed magnetic circuit magnetic core 5 is pressed and held by the support pin 14 from above and below, the variation of the pressing force due to the tolerance of the magnetic core size can be absorbed by the elasticity of the movable pin, and as a result, the stress applied to the magnetic core can be relaxed. Can be prevented from cracking.

Further, since the closed magnetic circuit magnetic core 5 is formed on the abutting surfaces of the two divided magnetic cores 4 without an adhesive, the variation in the magnetic gap size due to the variation in the coating thickness of the adhesive can be reduced. This suppresses variations in characteristics (inductance). In addition, since the step of adhering the abutting surfaces of the closed magnetic circuit core 5 in the second closed magnetic path magnetic core forming step is eliminated, it is possible to reduce the time-consuming work such as adhesive application and curing that require a long time at high temperature, and the number of steps is greatly reduced. Can be realized. Also, in terms of equipment, an adhesive coater, curing equipment, etc. are not required.

Furthermore, a concave cutout groove 15a is provided on the side surface 8a of the exterior portion covering the outer leg portion 2 of the closed magnetic circuit magnetic core 5, and the position of the magnetic core is regulated along the cutout groove 15a during molding. Since the supporting rod 16 to be inserted can be inserted from above and below, the magnetic core can be prevented from being displaced in the horizontal direction from the center of the magnetic core toward the outer leg.

Further, concave side cutout grooves 15b and 15c are provided on the side surface 8b of the exterior portion which covers the connecting leg 3 of the closed magnetic circuit magnetic core 5, and the magnetic core is positioned along the cutout groove during molding. Since the supporting rod to be regulated can be inserted from above and below, it is possible to prevent the magnetic core from being displaced in the horizontal direction from the center of the magnetic core to the direction without the outer leg.

Incidentally, the notch grooves 15a, 15b, 15
If at least a part of c is formed in a tapered shape, when the support rod 16 is pressed from the vertical direction, the closed magnetic circuit magnetic core 5 can be pressed from the diagonal direction, so that not only horizontal displacement but also vertical displacement can be prevented. it can.

As described above, in the third exterior part forming step, the outer leg 2 or the connecting leg 3 of the closed magnetic circuit magnetic core 5 is molded while the outer peripheral surface of the outer leg 2 or the connecting leg 3 is supported from the outside by the support rod. The positional deviation can be regulated during the manufacturing process, the characteristic variation due to the positional deviation of the magnetic core can be reduced, and the process quality can be stabilized.

Further, in the third exterior portion forming step, at least a part of the position of the injection gate 11 for the filling resin is provided on the ridge side portion 12 between the connecting leg 3 and the outer leg 2 of the closed magnetic circuit magnetic core 5. Since the method is adopted, when the filling resin is injected, it is divided into one that spreads on the connecting leg 3 and one that spreads on the outer leg 2, and for both the connecting leg 3 and the outer leg 2 of the closed magnetic circuit magnetic core 5. Since the filling can be performed smoothly, the closed magnetic circuit magnetic core 5 does not crack even if the injection pressure during injection is increased,
The filling portion can also be formed thin. Furthermore, since high-pressure molding is possible, there is no need to specially introduce an expensive low-pressure molding device.

Here, the diameter of the injection gate is made larger than the thickness of the side surface 8 of the exterior portion, the injection pressure is set to 800 kg / cm ² or more and 2000 kg / cm ² or less, and the injection time is set to 0.5 seconds or less. Equipment can be selected easily by providing molding conditions.

In the first embodiment of the present invention, the material of the filling resin is the liquid crystal polymer type, but if it is the epoxy type, the permeability and the adhesiveness are very good, so that the moisture resistance performance can be improved. In addition, since the stress on the magnetic core can be relaxed by producing by a low pressure molding method such as casting or transfer molding, the reliability of the product is improved.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS. 6 to 7.

FIG. 6 is a perspective view for explaining a magnetic core incorporated state of a coil component according to the second embodiment of the present invention, and FIG. 7 is a perspective view for explaining another example of the coil cap of the coil component. 6 to 7, 18 is a coil cap, and 19 is a wavy fold portion.

The basic structure is the same as that of FIGS. 1 to 5 in the first embodiment of the present invention. A big difference is that as shown in FIG. 6, an insulating coil cap 18 for restricting the position of the air-core coil 6 between the closed magnetic circuit magnetic core 5 and the air-core coil 6 is provided.
Is the point.

As described above, according to the configuration of FIG. 6 showing the second embodiment of the present invention, the insulation between the closed magnetic circuit magnetic core 5 and the air-core coil 6 can be improved. Furthermore, the minimum required thickness that is regulated by safety standards can be ensured.

If the material of the coil cap is the same as the resin forming the filling portion 7 and the exterior portion 8, since the same resin material is used, the conformability is improved, and the closed magnetic circuit magnetic core 5 and the air-core coil 6 are formed. The insulating property with is further improved.
Also, when applying for a standard for an insulation system, the content of the application can be simplified.

Further, in FIG. 7, a wavy fold portion 19 is formed on the flange portion of the coil cap 18, and the fold portion 19 produces an elastic force in the flange portion of the coil cap 18. Due to this spring property, when the closed magnetic circuit magnetic core 5 is incorporated, the length tolerance of the magnetic legs can be absorbed, and the stress on the closed magnetic circuit magnetic core 5 or the air-core coil 6 can be relaxed. This produces the effect of preventing damage to the coil coating and cracking of the magnetic core.

[0063]

As described above, according to the present invention, since the coil is formed without using the bobbin, the number of parts can be reduced and the space factor of the coil can be improved. In addition, since the gap between the air core coil and the closed magnetic circuit core is filled with resin, insulation is maintained even if the bobbin is removed, and since the exterior part of the closed magnetic circuit core is covered with insulating resin, it is insulated from external parts. It is also maintained and safety is increased.

On the manufacturing side, the bobbin removing and attaching work is eliminated. Further, the gap between the exterior of the closed magnetic circuit core, the air-core coil and the magnetic core can be filled once. Further, since the magnetic core can be pressed and held from the vertical direction, the work process for fixing the magnetic core can be reduced. Also, the molding time can be shortened.

As a result, the space factor of the coil is improved, and it is possible to provide at a low cost a coil component having good productivity and a method for manufacturing the coil component which can secure safety from the outside.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a coil component showing a first embodiment of the present invention.

FIG. 2 is a perspective view for explaining a magnetic core assembled state of the coil component.

FIG. 3 is a perspective view showing a completed assembly of the coil component before being filled with resin.

FIG. 4 is a perspective view of a finished product of the coil component.

FIG. 5 is a transparent plan view of the coil component.

FIG. 6 is a perspective view for explaining a magnetic core assembled state of the coil component according to the second embodiment of the present invention.

FIG. 7 is a perspective view illustrating another example of the coil cap.

[Explanation of symbols]

1 middle leg 2 outer legs 3 connecting legs 4 split magnetic core 5 Closed magnetic circuit core 6 air core coil 7 Filling section 8 Exterior 9 rectangular wire 10 Drawer 11 injection gate 12 Ridge 13 exposed magnetic core 14 Support pin 15 Notch groove 16 Support rod 17 Tapered part 18 coil cap 19 Wavy folds

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoshi Ueda             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Tsukasa Suzuki             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Tomio Marui             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5E043 AB02 AB04                 5E044 CA09

Claims (23)

[Claims] 1. A closed magnetic circuit magnetic core formed by combining two split magnetic cores each having a middle leg, an outer leg facing the middle leg, and a connecting leg connecting the middle leg and the outer leg. An air-core coil inserted into the middle leg, the inside of the closed magnetic circuit magnetic core is filled with resin to form a filling portion, and the closed magnetic circuit magnetic core is covered with resin to form an exterior portion, and the filling portion is formed. A coil component, wherein the resin forming the exterior portion is the same. 2. The coil component according to claim 1, which is an air-core coil in which a rectangular wire is wound adjacently in the longitudinal direction. 3. The coil component according to claim 1, wherein the closed magnetic circuit core is a dust core. 4. The coil component according to claim 1, wherein the material of the filling resin is a liquid crystal polymer made of an aromatic polyester resin. 5. The coil component according to claim 1, wherein the material of the filling resin is an epoxy resin. 6. The coil component according to claim 1, wherein at least one magnetic core exposed portion which is not covered with resin is provided on the exterior portion. 7. The coil component according to claim 6, wherein the exposed magnetic core portions are provided on the upper and lower surfaces of the connecting legs of the closed magnetic circuit magnetic core. 8. The coil component according to claim 1, wherein a recessed notch groove is provided on a side surface of the exterior portion that covers the outer leg portion of the closed magnetic circuit core. 9. The coil component according to claim 1, wherein a recessed notch groove is provided on a side surface of the exterior part covering the connecting leg of the closed magnetic circuit magnetic core. 10. The coil component according to claim 8, wherein at least a part of the notch groove is formed in a tapered shape. 11. The coil component according to claim 6, wherein a closed magnetic circuit magnetic core is formed on the abutting surfaces of the two divided magnetic cores without interposing an adhesive. 12. The coil component according to claim 1, wherein an insulative coil cap for regulating the position of the coil is arranged between the closed magnetic circuit magnetic core and the air-core coil. 13. The coil component according to claim 12, wherein the material of the coil cap is the same as the resin forming the filling portion and the exterior portion. 14. The coil component according to claim 13, wherein a wavy fold portion is formed on the flange portion of the coil cap. 15. A first coil forming step of winding an air core coil and a second closed magnetic path magnetic core forming step of inserting a middle leg into the air core coil to incorporate a closed magnetic circuit magnetic core, the closed magnetic circuit magnetic core and the coil. A method of manufacturing a coil component, which comprises a third exterior part forming step of forming the exterior part and the filling part at the same time by coating the resin with a filling resin. 16. The method of manufacturing a coil component according to claim 15, wherein the rectangular wire is wound adjacently in the vertical direction in the first air-core coil forming step. 17. The method for manufacturing a coil component according to claim 15, wherein the coil member is formed by injection molding in the third exterior part forming step. 18. The third exterior part forming step, wherein at least a part of the injection gate position of the filling resin is provided on the ridge of the connecting leg of the closed magnetic circuit magnetic core and the outer leg. 17. The method for manufacturing a coil component according to item 17. 19. The diameter of the injection gate is larger than the thickness of the side surface of the exterior part, and the injection pressure is 800 kg / cm ² or more 2
Together to 000kg / cm ² or less, the manufacturing method of the coil component according to claim 18, wherein the injection time was within 0.5 seconds. 20. The third exterior part forming step is a step of forming the exterior part while pressing and supporting the connecting legs of the closed magnetic circuit magnetic core from above and below with support pins.
7. The method for manufacturing a coil component according to 7. 21. The method of manufacturing a coil component according to claim 20, wherein at least one of the support pins is movably pressed and supported while being molded. 22. The third exterior part forming step is a step of molding while supporting the outer peripheral surface of the outer leg or the connecting leg of the closed magnetic circuit magnetic core from the outside by a support rod.
A method for manufacturing the described coil component. 23. The method for manufacturing a coil component according to claim 20, wherein the step of adhering the abutting surfaces of the closed magnetic circuit cores is eliminated in the second closed magnetic circuit magnetic core forming step.