JP2012043959A - Coil component and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coil component with high electric insulation and high reliability.SOLUTION: The coil component comprises a closed magnetic circuit magnetic core 14 formed by combining two split magnetic cores 13 having a middle leg 10, an external leg 11 opposed to the middle leg 10, and a concatenation leg 12 concatenating the middle leg 10 and the external leg 11; and an air-core coil 15 inserted in the middle leg 10. The closed magnetic circuit magnetic core 14 is filled with resin to form a filling part 17, and the closed magnetic circuit magnetic core 14 is covered with the resin to form an exterior part 16. The filling part 17 and the exterior part 16 are formed of an identical resin. A convex part 18 communicated in a combining direction of the split magnetic cores 14 is provided on a side of the exterior part 16, and a bottomed hole 19 bored in a communication direction of the convex part 18 is provided on the convex part 18. One part of a side wall 20 of the bottomed hole 19 is formed by the external leg 11.

Description

  The present invention relates to a coil component used in various electronic devices.

  Hereinafter, conventional coil components will be described with reference to the drawings. In the conventional coil component, for example, as shown in FIG. 5, the coil part 2 is held by the two split magnetic cores 1 via the coil support 3 and then the terminal part 4 is pulled out as shown in FIG. Thus, the entire part from the inside to the exterior side was molded with the exterior resin 5 to form the coil component 6 (Patent Document 1).

JP 2003-173917 A

  In the conventional coil component 6, when the terminal part 4 is pulled out from the exterior resin 5 and the exterior resin 5 is molded, the positional relationship between the divided magnetic core 1 shown in FIG. 5 and the exterior resin 5 shown in FIG. In order to prescribe | regulate, the holding pin (not shown) was provided in the mold die (not shown), and the to-be-molded body was hold | maintained by it. Thereby, the window portion 7 shown in FIG. 6 in which the surface of the split magnetic core 1 shown in FIG. 5 is partially exposed on the surface of the exterior resin 5 is formed on the top surface 8 side or the mounting substrate 9 side. When the distance between the window portion 7 and the electrical signal pattern (not shown) provided on the mounting substrate 9 is close, there is a possibility that a sufficient insulation distance cannot be obtained, resulting in a decrease in insulation reliability. As an arrangement corresponding to the above, there is a problem that it is necessary to consider mounting the coil component 6 on the mounting substrate 9.

  Therefore, the present invention provides a highly reliable coil component having high electrical insulation.

  In order to achieve this object, a closed magnetic circuit formed by combining two divided magnetic cores having a middle leg, an outer leg facing the middle leg, and a connecting leg that connects the middle leg and the outer leg. A magnetic core and an air core coil inserted into the middle leg, and the inside of the closed magnetic path magnetic core is filled with resin to form a filling portion; and the closed magnetic path magnetic core is covered with resin to form an exterior portion and the filling is performed And a resin that forms the exterior portion, and a convex portion that is continuous in the direction in which the divided magnetic cores are combined is provided on the side surface of the exterior portion, and a bottomed hole that is perforated in the direction in which the convex portions are continuous is provided on the convex portion. And a part of the side wall of the bottomed hole is formed by the outer leg.

  According to the present invention, insulation between the magnetic core inside the coil component and the mounting surface can be accurately maintained, and the magnetic core can be stably held by the exterior made of resin, thereby improving the reliability of the coil component. Is.

Sectional drawing of the coil components in one Embodiment of this invention The perspective view of the coil components in one Embodiment of this invention Sectional drawing of the 1st process in the manufacturing method of the coil components in one Embodiment of this invention Sectional drawing of 2nd process in the manufacturing method of the coil components in one Embodiment of this invention An exploded perspective view of a conventional coil component Perspective view of conventional coil parts

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a sectional view of a coil component according to an embodiment of the present invention, and FIG. 2 is a perspective view thereof. Further, the cross-sectional view of FIG. 1 shows a state of a cross section at substantially the center of the perspective view of FIG. A closed magnetic circuit formed by combining two divided magnetic cores 13 having the middle leg 10 shown in FIG. 1, the outer leg 11 facing the middle leg 10, and the connecting leg 12 that connects the middle leg 10 and the outer leg 11. A magnetic core 14 and an air core coil 15 inserted into the middle leg 10 to provide magnetic coupling to the closed magnetic path magnetic core 14 are provided, and an exterior portion 16 that covers the outer periphery of the closed magnetic path magnetic core 14 is formed of resin, and at the same time a closed magnetic path magnetic core The filling portion 17 is formed of resin so as to fill a portion where the air-core coil 15 which is the inside of 14 is disposed. Here, the exterior part 16 and the filling part 17 are sealed with the same resin. Here, the filling portion 17 is not formed just inside the closed magnetic path magnetic core 14, but the resin is filled so as to form the filling portion 17 so as to completely include the air core coil 15.

  Further, at least a side surface of the exterior portion 16 is provided with a convex portion 18 as shown in the perspective view of FIG. A bottomed hole 19 drilled in 18 consecutive directions is formed. As shown in FIG. 1, a part of the side wall 20 of the bottomed hole 19 is formed by the outer peripheral surface of the outer leg 11.

  With this configuration, even when the outer peripheral side of the split core 12 is held by a fixing pin (not shown) in fixing the split magnetic core 13 when forming the exterior portion 16 and the filling portion 17, the held portion is Since the magnetic core side wall 20a on the outer leg 11 side of the side wall 20 is present without being directly exposed to the outside due to the presence of the convex portion 18, the mounting surface 21 and the magnetic core side wall 20a maintain a large creepage distance. In addition, the reliability regarding insulation can be maintained in a high state.

  The bottomed hole 19 can also be easily applied when capturing the insulation state between the air core coil 15 and the closed magnetic path magnetic core 14. This is a figure corresponding to the lead-out portion of the air-core coil by inserting a contact body (not shown) into the magnetic core side wall 20a of the bottomed hole 19 from the opening side of the bottomed hole 19 and bringing it into contact with it. This is because, by using the electrode terminal 22 shown in 2 as the other electrode to be measured, it is possible to obtain a withstand voltage characteristic when a high potential difference is given between the two electrodes to be measured. Then, regarding the depth of the bottomed hole 19 shown in FIG. 1, the bottomed hole 15 is formed so that the outer side of the outer leg 11 of the split magnetic core 13 located on the mounting surface 21 side becomes a part of the magnetic core side wall 20a. Is desirable. As a result, it is possible to capture the insulation state of the lower divided magnetic core 13 (the divided magnetic core 13 positioned on the mounting surface 21 side) and the upper divided magnetic core 13 separately from the air core coil 15. In general, a fixing adhesive (not shown), a film for forming a magnetic gap (not shown), or the like is generally disposed between the upper divided magnetic core 13 and the lower divided magnetic core 13. It is. Therefore, in some cases, these function as insulators. Therefore, even if the insulation state between the upper split magnetic core 13 and the air core coil 15 is measured and the insulation can be maintained, the lower magnetic core 13 is not necessarily in the lower side. Even if the insulation between the split magnetic core 13 and the air core coil 15 can be maintained, a situation in which it cannot be determined occurs. Therefore, by enabling direct measurement of the insulation state between each of the lower divided core 13 and the upper divided core 13 and the air core coil 15, it is possible to further improve quality reliability. It is. Further, since the bottomed hole 19 is opened upward, moisture and the like can easily enter the bottom direction, but the bottomed hole 19 is formed so as to be disposed outside the outer leg 11, so that it is resistant to corrosion. Moisture or the like does not approach the air-core coil 15 that needs to be considered for its properties, etc., and reliability of corrosion and the like is not reduced.

  Further, as shown in FIG. 2, the strength of the exterior portion 16 is improved by forming a convex portion 18 extending in the same direction as the bottomed hole 19 so as to surround the bottomed hole 19 around the bottomed hole 19. Is possible. This is not only to improve the strength by simply increasing the volume of the exterior portion 16, but also to avoid the discontinuous formation of the resin. For example, in the conventional coil component shown in FIG. 6, the region 7A located between the upper window portion 7 and the lower window portion 7 is used when resin is flowed to the top surface 8 side or the mounting surface 9 side. When the gate is formed, it is a region that requires a flow in a direction perpendicular to the flow direction of the resin main body, and since it becomes a narrow region, a weld or the like may occur. However, as shown in FIG. 2, by forming the protrusion 18 around the bottomed hole 19, it is possible to avoid restricting the flow direction of the resin when forming the exterior portion 16 to one direction. Etc., and the strength per unit volume of the exterior portion 16 and the reliability can be improved. For example, when it is assumed that the resin is injected from the top surface portion 23 side, in the area A below the bottomed hole 19, in addition to the route through the side surface portion 24, the convex portion There will be a route through 18. Therefore, since the resin is supplied from a plurality of directions without being supplied from one limited direction, the flow becomes smooth, and the possibility that a discontinuous portion is generated in the formed exterior portion 16 is suppressed.

  Next, the resin molding process in this coil component will be described in order. FIG. 3 is a sectional view showing a first step of resin molding of the coil component. First, after the air core coil 15 is incorporated into the split magnetic core 13, the split magnetic core 13 is disposed in a cavity 27 for molding an exterior resin formed between the upper mold 25 and the lower mold 26. At this time, the split magnetic core 13 in the vertical direction in FIG. 3 is fixed with the support pin 28 that protrudes from the upper mold 25 and presses downward, and the upward pressing force that protrudes from the lower mold 26. The two split magnetic cores 13 are pressed and fixed from the connecting leg 12 or the surface on the connecting leg 12 side by a movable pin 29 having a fixed position. The movable pin 29 is supplied with a pressing force by an elastic mechanism 30.

  Further, the divisional magnetic core 13 in the left-right direction is fixed in a positional relationship in which the divisional magnetic core 13 is sandwiched by bringing the fixing pin 31 protruding from either the upper mold 25 or the lower mold 26 into close contact with the divisional magnetic core 13. By doing so, the position of the divided magnetic core 13 is defined. Here, when the fixing pin 31 protrudes from the upper mold 25 side, the tip of the fixing pin 31 is defined so as to reach a position where it contacts the outside of the outer leg 11 of the divided magnetic core 13 positioned on the lower side. . Further, when the fixing pin 31 is protruded from the lower mold 26 side (not shown), the fixing pin 31 is defined so as to reach a position in contact with the outer side of the outer leg 11 of the divided magnetic core 13 located on the upper side.

  In the above first step, the position where the fixing pin 31 is provided is a positional relationship in which the divided magnetic core 13 is sandwiched in the left-right direction. In addition to this, as shown in FIG. 2, it corresponds to the second bottomed hole 19a. A front and rear fixing pin (not shown) may be provided to provide a front and rear fixing function in FIG. This is because, as shown in FIG. 3, the outer leg 11 has a thickness, and therefore it is possible to provide a front and rear fixing pin for fixing in the front and rear direction at a position corresponding to this thickness. . Thereby, since the division | segmentation magnetic core 13 in a horizontal direction is fixed by the front-back and left-right direction, more exact shaping | molding is enabled.

  Next, the second step will be described with reference to the cross-sectional view of FIG. In this step, the resin that is softened in an uncured state by a predetermined pressure is injected from the gate portion 32 around the outer periphery of the split magnetic core 13 and the periphery of the air core coil 15 that have been positioned in the first step. Sealing is performed. At this time, the movable pin 29 is pushed back by the pressure from the uncured resin 33 so as to be in a non-contact state with the divided magnetic core 13 and, of course, the mounting surface that is below the divided magnetic core 13 in FIG. On the side, the exposed part of the split magnetic core 13 does not occur. On the other hand, with respect to the fixed pin 31, the positional relationship between the fixed pin 31 and the upper and lower divided magnetic cores 13 does not change, and the contact state between the fixed pin 31 and the outer legs 11 of the divided magnetic cores 13 does not loosen. At the same time, the shapes of the upper die 25 and the lower die 26 are determined so that the fixing pin 31 is covered with the resin 33 except for the surface in contact with the divided magnetic core 13.

  Here, the shape of the fixing pin 31 may be a columnar shape having a flat surface at the portion in contact with the divided magnetic core 13, such as a polygonal columnar shape such as a quadrangular column or a hexagonal column, Alternatively, it may be a cylindrical shape and at least a columnar portion having a flat surface at the contact portion with the divided magnetic core 13, but from the viewpoint of ensuring smooth fluidity in a state where the resin 33 is softened. It is desirable to use a cylindrical shape having a flat surface at the part.

  Then, in the next third step, the fixing pin 31 is removed after the resin 33 is cured, and then the combined state of the upper mold 25 and the lower mold 26 is released and the coil component is taken out. Yes.

  By applying the above steps and sealing the coil component with resin, both the upper and lower divided magnetic cores are fixed in the left-right direction by a single linear fixing pin 31. This can be performed accurately, and the exterior portion 16 and the filling portion 17 shown in FIG. 1 can be stably formed. Further, as shown in FIG. 4, since the fixing pin 31 is always in close contact with the split magnetic core 13 during the molding process, the close contact portion is exposed to the split magnetic core 13 after the resin molding process is completed. It is possible to apply this part to the measurement of withstand voltage characteristics as described above. Further, the convex portion 18 is formed so as to surround the fixing pin 18, so that the resin supply to the A region can be performed with respect to the fixing pin 31 with respect to the path that proceeds to the A region via the convex portion 18 and the drawing plane. Since both the path from the front side and the back side to the A region can be ensured, it is possible to form an accurate and highly reliable exterior resin without generating welds.

  The coil component of the present invention has an effect of enabling high electrical insulation and reliability to be maintained, and is useful when applied to various electronic devices.

DESCRIPTION OF SYMBOLS 10 Middle leg 11 Outer leg 12 Connecting leg 13 Split magnetic core 14 Closed magnetic path magnetic core 15 Air core coil 16 Exterior part 17 Filling part 18 Convex part 19 Bottomed hole 19a Second bottomed hole 20 Side wall 20a Magnetic side wall 21 Mounting surface 22 Electrode terminal 23 Top surface portion 24 Side surface portion 25 Upper die 26 Lower die 27 Cavity 28 Support pin 29 Movable pin 30 Elastic mechanism 31 Fixed pin 32 Gate portion 33 Resin

Claims (2)

Middle legs,
An outer leg facing this middle leg,
A closed magnetic circuit core formed by combining two split magnetic cores having connecting legs connecting the middle leg and the outer leg;
An air-core coil inserted into the middle leg,
Filling the closed magnetic path magnetic core with resin to form a filling portion,
Covering the closed magnetic path magnetic core with a resin to form an exterior part and the same resin as the filling part and the exterior part,
Provided on the side surface of the exterior portion is a convex portion continuous in the direction of combination of the split magnetic cores,
This convex part is provided with a bottomed hole that is perforated in the direction where the convex part continues,
A part of the side wall of the bottomed hole is a coil component formed by the outer leg. A closed magnetic circuit core formed by combining two split magnetic cores;
An air-core coil having a magnetic coupling with the closed magnetic path core;
A filling portion for filling the closed magnetic path magnetic core with resin;
In the manufacturing process of the coil component provided with an exterior portion that covers the closed magnetic path magnetic core with resin,
The split mold core is pressed in the up and down direction by the movable pins protruding from the upper mold and the lower mold of the exterior resin molding mold composed of an upper mold and a lower mold, and the upper mold is butted Alternatively, the side surface of the fixed pin protruding vertically from either one of the lower molds on the left and right sides of the split magnetic core is brought into contact with the split magnetic core to position the split magnetic core in the left-right direction within the exterior resin molding die. A first step of performing
A second step of injecting the uncured resin into the exterior resin molding die to cover the closed magnetic path magnetic core and to cover a non-contact surface of the fixed pin with the split magnetic core; ,
And a third step of releasing the fastening state of the exterior resin molding die after extracting the fixing pin after the resin is cured.

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