JPH0760774B2 - Manufacturing method of small common mode coil - Google Patents

Description

The present invention relates to a method for manufacturing a small-sized common mode coil with a lead terminal, which is sheathed with a resin.

[Conventional technology]

Conventionally, there is a small inductor element formed by winding a coated electric wire around a toroidal magnetic core. This inductance element is housed in an outer case,
It is used as a common mode coil by winding a winding terminal around a lead terminal connected to an external circuit and soldering it, and then filling the inside of the case with resin, insulating varnish or the like. Therefore, in this type of common mode coil, four terminals 8 are projectingly provided on the lower surface as in the example shown in FIG. 4, and the inductance element 1 is housed in the outer case 9 so that vibration resistance is particularly required. In this case, the outer case 9 is filled with an insulating varnish or the like to fix and protect the internal elements.

[Problems to be solved by the invention]

However, such a conventional common mode coil has a drawback that when the winding terminal is connected to the lead terminal of the outer case, the winding terminal is easily bent and mounting on the electronic device or the circuit board is troublesome. Further, in the common mode coil, as shown in FIG. 4, the four terminals 8 are not arranged side by side in a line, so that there is a drawback that the common mode coil cannot be automatically assembled using an automatic insertion machine.

[Means for solving problems]

A method of manufacturing a small-sized common mode coil according to the present invention includes a stand-off portion provided with a holding strip and a crimping piece made of a metal material facing each other at a tip thereof, and a thin extension extending to the other end side of the stand-off portion. A circuit having a strip-shaped lead frame in which a plurality of lead terminal portions, each of which is composed of a lead terminal piece, are vertically erected at regular intervals, and which is made of an insulating material and has a through hole in the center between the holding strip and the crimping piece. An inductor element in which a plurality of terminal circuit patterns provided at the same intervals as the lead terminal portions are sandwiched on the edge of the substrate, and a winding material coated on a toroidal magnetic core made of a high magnetic material is wound. Is fitted into the through hole, the end of the winding material is welded to the crimping piece by resistance welding, the outer circumference of the circuit board is covered with resin, and the lead terminal piece is cut from the strip-shaped lead frame. And wherein the door.

[Action]

Since a plurality of common mode coils covered with resin are continuously fixed to the lead terminal frame, they are used by cutting them off at the standoff section whenever necessary. Moreover, since the common mode coils are arranged in order on the lead terminal frame, the coils can be attached to the device or the board by an automatic machine.

〔Example〕

A method for manufacturing a small common mode coil according to the present invention will be described with reference to examples. As shown in FIG. 1, the inductor element 1 is formed by winding two coated winding materials 3 around a toroidal ferrite magnetic core 2 around a bifilar winding. Further, as shown in FIG. 2, the thin circuit board 4 to which the inductor element 1 is attached has a plurality of terminals for terminals which are formed by photo-etching a copper clad laminated printed wiring board on the edge thereof. A circuit pattern 41 and a through hole for accommodating the inductor element 1 in the center
42 and are pierced.

Here, FIG. 3 (a) shows the structure of the lead terminal frame in a state before being joined to the circuit board. here,
The main frame 51 is a band-shaped metal plate having high elasticity and good conductivity such as brass, beryllium copper, stainless steel, iron, or alloys thereof, and the thin lead terminals are arranged on one edge of the main frame 51 at the same intervals as the circuit pattern 41. A piece 52 and a standoff portion 55, which is slightly wider than the piece 52, are formed by punching or etching in the direction perpendicular to the main frame 51. The circuit board 4 is attached to the tip of the standoff portion 55.
A holding strip 53 for holding the lead and a lead crimping piece 54 are provided so as to face each other.

FIG. 3 (b) shows the step of holding the circuit board. The circuit pattern 41 of the circuit board 4 is inserted between the holding strips 53 and the crimping pieces 54, which are divided into two lids, and the positions are aligned. Be held.

Next, FIG. 3 (c) shows a step of assembling the inductor element, in which the inductor element 1 is inserted into the through hole 42 of the circuit board 4.
The lead wire 31 end of the winding material 3 is housed in the crimping piece 54, and the welding wire of the electric resistance welding machine is used to crimp the crimping piece 54 together. Current is applied to peel off the coating of the lead wire, and then a current sufficient to weld the lead wire and the crimping piece 54 is applied to generate an appropriate welded mass at the joint portion, and the lead wire and the lead terminal piece 52 are Connect. After that, the excess lead wire 31 is cut and removed, and the circuit pattern 41 and the holding strip 53 are soldered with a high melting point solder.
Then, the surface of the inductor element 1 is coated with a silicone resin exhibiting a low residual stress strain, an epoxy resin, or the like to form the protective film 6.

Then, at the stage shown in FIG. 3 (d), the outer portion of the circuit board 4 is immersed in an epoxy resin or an electrically insulating resin such as a resin liquid, leaving the standoff portion 55, and the outer casing 7 is applied. Then, the lead terminal piece 52 is cut from the main frame 51 leaving the required length, and a small common mode coil is completed as a component.

〔The invention's effect〕

As described above, according to the present invention, the positioning of the small inductor element 1 and the lead wire 31 can be easily and firmly connected to the external terminal. Therefore, an unnecessary external force is not applied to the terminal in the work of connecting the lead wire 31 of the coil, a defective product such as bending damage is not generated, and a highly reliable coil can be obtained. Also, since the terminals are lined up in the same plane, it is easy to mount the inductor element 1 by the automatic mounting machine based on the positioning holes 56 by taking advantage of the features of the taping parts that are attached to the paper backing at regular intervals. The productivity is high and the economic efficiency is improved, and the effect is great.

[Brief description of drawings]

1 is an external perspective view of an inductor element used in a small common mode coil according to the present invention, FIG. 2 is an external perspective view of a circuit board used in the present invention, and FIG. 3 is a small common mode coil of the present invention. FIG. 4 is a plan view for explaining the step of assembling the terminal in steps, and FIG. 4 is an external perspective view showing an example of a conventional small common mode coil. In addition, 1: inductor element, 2: magnetic core, 3: winding material, 4: circuit board, 5: lead terminal frame, 6: protective film, 7: exterior, 8: terminal, 9:
Outer case, 31: Lead wire, 41: Circuit pattern, 42: Through hole, 5
1: Main frame, 52: Lead terminal piece, 53: Holding strip, 54: Crimping piece, 55: Standoff part, 56: Positioning hole.

Claims (1)

[Claims] 1. A lead comprising a stand-off portion having a holding strip and a crimping piece made of a metal material, which are opposed to each other at a tip thereof, and a thin lead terminal piece extending to the other end of the stand-off portion. A strip-shaped lead frame in which a plurality of terminal portions are vertically erected at a constant interval is provided, and between the holding strip and the crimping piece,
On a toroidal magnetic core made of a high magnetic material, which holds a plurality of terminal circuit patterns provided at the same intervals as the lead terminal portions on the edge of a circuit board made of an insulating material and having a through hole in the center, The inductor element wound with the covered winding material is fitted into the through hole, the end of the winding material is welded to the crimping piece by resistance welding, and then the outer circumference of the circuit board is covered with resin, and the lead terminal piece is provided. Is cut from the strip-shaped lead frame.