JP2915151B2 - Method of manufacturing choke coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a chip type choke coil using a split magnetic core.

[0002]

2. Description of the Related Art A conventional chip type choke coil using a split type core, for example, an EE type core has a horizontal winding core, and a surface-mounted terminal or a core itself is used for surface mounting. The required winding is wound around a winding frame provided with a terminal, and the end of the winding is connected to the terminal, and then the center magnetic leg of the EE type core is inserted into the winding core with the base horizontal, and divided. The structure was such that the clamping cores and the like were attached to the split magnetic core by abutting the molding cores.

[0003]

The performance and miniaturization of electronic devices are continually progressing. Electronic components for noise suppression to suppress electromagnetic noise generated in electronic devices are currently indispensable components in electronic devices.
There is a demand for further miniaturization.

[0004] In a conventional choke coil for noise prevention using a bobbin, the bobbin must withstand the stress during winding of the winding and must have such strength that the winding does not collapse. Therefore, there is a limit to the reduction of the wall thickness and a limit to the miniaturization.

[0005]

According to the present invention, an air-core coil is connected to a lead terminal piece of a lead frame, and the air-core coil and the lead terminal piece are buried by resin molding to penetrate a magnetic core into a split type magnetic core. Step of forming a sealing body having a hole and a base on which a part of the split-type magnetic core is placed, separating the sealing body from the lead frame, and shaping a lead terminal piece left in the sealing body into a chip type. And then assembling the split magnetic core to the closed magnetic path. That is, according to the present invention, an air-core coil is arranged in the center of a section of a lead frame having two sets of opposing lead terminal pieces in one section so that the air-core coil is horizontal in the axial direction, and an air-core coil is provided in the lead terminal piece. A coil winding terminal is connected, the air-core coil and the lead terminal piece are buried, and a seal having a through hole for inserting a magnetic leg of the split magnetic core and a base portion at least at lower portions at both ends in the axial direction of the air-core coil. A choke coil, comprising: a step of forming a stationary body by a resin mold; and a step of separating the sealing body from the lead frame, shaping the lead terminal pieces, and then assembling the split magnetic core to the closed magnetic path. Production method.

[0006]

The air core coil is a small sealed body to which the split magnetic core can be assembled. The lead terminal pieces form chip-type terminals for external connection in the sealing body.

[0007]

FIG. 1 is a longitudinal perspective front view of an embodiment of a choke coil according to the present invention. An air-core coil 2 is buried in a sealing body 1 and a part of a lead terminal piece 3 is buried in the sealing body 1.
Is a choke coil which is assembled by horizontally abutting on the side.

Referring to FIG. 2 and FIG. 3, the steps of manufacturing this choke coil will be described. In FIG. 2, as shown in the left front section, two sets of opposing leads are provided in a fixed section formed by a partition frame 7 that connects positioning frames 6 parallel to each other at a fixed interval, as shown in the section on the left side. This is one in which terminal strips 3 are formed. Lead terminal strip 3
Has an upright piece 8 near the tip of the side edge on the section center side. The upright small piece 8 is a deformed portion for preventing the lead terminal piece 3 provided integrally with the sealing body 1 from falling off from the sealing body 1. The air-core coil 2 is formed by winding two self-fusing wires in a bifilar form and fixing them. As shown in the second section of FIG. 2, the air-core coil 2 is disposed at the center of the section so that the axial direction is parallel to the positioning frame 6, and the end of the air-core coil 2 is connected to the tip of the lead terminal piece 3. To the part by spot welding.

Next, the air-core coil 2 and the leading end of the lead terminal piece 3 are put into a molding die, and a resin mold is used to form the sealing body 1 shown in the right-most section in FIG. The sealing body 1 has a through hole 9 concentric with the center hole of the air-core coil 2 as shown in a transparent manner.
And a pedestal portion 10 that protrudes in four directions at the upper and lower portions of the air-core coil 2. As shown in FIG. 3 together with the EE-type core 4 in the appearance of the sealing body 1, the through-hole 9 has a size corresponding to the central magnetic leg 41 of the EE-type core 4 shown in FIG. The upper and lower surfaces 9 and the upper and lower surfaces which cover the air-core coil 2 are the same, and the EE-shaped core 4 is
Are the same dimensions as the external dimensions of.

The bottom surface of the lead terminal piece 3 is exposed on the bottom surface of the sealing body 1. The lead terminal piece 3 is cut in the middle between the sealing body 1 and the positioning frame 6, and is shaped so that the free end remaining on the sealing body 1 is in close contact with the side surface of the base 10 of the sealing body 1. A choke coil is surface-mounted on a substrate and can be connected to a conductor of the substrate from the side by a soldering iron.

An EE-shaped core 4 is assembled to the sealing body 1 in a closed magnetic circuit, and a fastener (not shown) is attached to the EE-shaped core 4 to complete a substantially rectangular parallelepiped common mode choke coil.

In the present embodiment, the case where the air-core coil 2 has two windings of bifilar winding has been described. However, one winding may be used. And the unused lead terminal pieces 3 can be cut off at the bottom line of the sealing body 1 to form a normal mode choke coil.

FIG. 4 shows the appearance of another sealing body 11 made in the same procedure as described in FIG. The sealing body 11 has a shape in which a pedestal portion 12 is provided at the lower part of both ends of the air-core coil in the axial direction. As in the case of the sealing body 1, the lead terminal pieces 3 are integrally provided on the base 12. As shown in FIG. 5, the sealing body 11 is assembled into a chip type choke coil by assembling a UU type core 13 which is a split magnetic core. In addition, since the UU-shaped core protrudes outside of the sealing body 11, it becomes difficult to handle. However, the UU-shaped core is laid on the sealing body and assembled.
A choke coil having a small height can be formed by assembling an E-shaped core.

[0014]

According to the method of the present invention, the air-core coil and the lead terminal piece of the lead frame are formed by resin molding.
Since it is molded into a sealed body with chip-type terminals and assembled with a split-type magnetic core, it can be manufactured efficiently using an automated device, and can efficiently demonstrate the performance of the split-type magnetic core, and is inexpensive and small-sized chip-type choke. Can provide coil.

[Brief description of the drawings]

FIG. 1 is a longitudinal perspective front view showing an embodiment of a choke coil according to the present invention.

FIG. 2 is an explanatory view of a manufacturing process of the choke coil shown in FIG.

FIG. 3 is a perspective view in which an EE-type core is incorporated in a sealed body of an air-core coil.

FIG. 4 is an external view showing another embodiment of the sealing body according to the present invention.

FIG. 5 is an external view of a choke coil in which an EE-type core is vertically installed using the sealing body of FIG. 4;

FIG. 6 is an external view of a choke coil in which an EE-type core is horizontally installed using the sealing body of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing body 2 Air core coil 3 Lead terminal piece 4 EE type core 5 Lead frame 6 Positioning frame 7 Partition frame 8 Upright small piece 9 Through hole 10 Base 11 Seal 12 Base 13 UU-shaped core 41 Central magnetic leg

Claims (1)

(57) [Claims] 1. An air-core coil is disposed in the center of a section of a lead frame provided with two sets of opposing lead terminal pieces in one section, and the air-core coil is arranged in the axial direction to be horizontal. A coil winding terminal is connected, the air-core coil and the lead terminal piece are buried, and a seal having a through hole for inserting a magnetic leg of the split magnetic core and a base portion at least at lower portions at both ends in the axial direction of the air-core coil. A choke coil, comprising: a step of forming a stationary body by a resin mold; and a step of separating the sealing body from the lead frame, shaping the lead terminal pieces, and then assembling the split magnetic core to the closed magnetic path. Production method.