JPH0210813A - Manufacture of small-sized choke coil - Google Patents

Abstract

PURPOSE:To form a winding section to a small-sized core, and to automate a winding process by combining and joining a signal conductor frame, in which a signal conductor is shaped of a thin band-shaped metallic plate, and a flexible printed wiring board. CONSTITUTION:Film tapes 20 for temporary fixing are stuck to sections, into which bead cores are penetrated, in the signal conductor terminals 12 of a signal conductor frame 10. A plurality of the bead cores 1 are aligned and held at regular array pitches, the bead cores 1 are inserted to inserting guide sections 17 and the terminals 12 for signal conductors, adhesives 18 are applied and fastened onto the film tapes 20 for temporary fixing, and the terminals 12 for the signal conductors and the inserting guide sections 17 are inserted into the bead cores 1, and put into positioning sections 16 and positioned and fixed. FPBs 30 are joined with the terminals 12 for the signal conductors and junction seats 15 in the signal conductor frame 10, and windings in one-time winding in which the inside and outside diameters of the bead cores are connected by one conductors are completed. Sheathing molds 19 are executed by an electric insulating resin. Terminals 14 for support are cut and removed while terminals 13 for external leading-out and the inserting guide sections are shaped, thus acquiring a large number of small-sized choke coils.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a countermeasure component for suppressing unnecessary electromagnetic radiation noise in electronic equipment, which is a small choke coil mounted on a circuit board of a digital equipment. Regarding the manufacturing method.

[Conventional technology]

As shown in FIG. 6, a conventional small choke coil of this type has a structure including a bead core 1, a coated copper M2, a storage case 3, a pin terminal 4, an upper cover 5, and a fixing resin 6.

First, a coated copper wire 2 is wound around a bead core 1, and both ends 7 of the copper wire are peeled off to form a coil. The coil is then stored in the storage case 3, and its terminal 7 is connected to the pin terminal 4 and soldered. Next, a fixing resin 6 is cast, the bead core is fixed to the storage case, and the upper lid 5 is fitted to the storage case, thereby obtaining multiple small choke coils.

[Problem that the invention seeks to solve]

Conventionally, in this type of small choke coil (hereinafter referred to as a small coil), the diameter of the bead core is usually 1 to 7 am, the through hole has an inner diameter of 0.4 to 6 mm, and a length of about 3 to 10 mm. The coated copper wire used is coated with vinyl, Teflon, enamel, urethane, etc., and is extremely thin with a thickness of 0.1 to 0.5 mm.

Furthermore, since a large number of devices are mounted side by side on the circuit board of electronic equipment, several devices are often housed in a storage case.

Therefore, since the bead core has a small diameter, it is difficult to automate the winding process, and the bead core is manufactured manually. Furthermore, the process of terminal-processing the ends of the windings and connecting them to pin terminals must also be done manually, which has the disadvantage of high processing costs due to its structure.

[Means for solving problems]

The present invention combines and connects a signal line frame made of a thin metal plate with a flexible printed wiring board to form a winding portion around a small core, and also connects a large number of small coils at once. The present invention provides a method for manufacturing a small choke coil that solves the above-mentioned problems.

That is, the present invention provides (1) a small choke coil in which a signal wire penetrates a bead core and is integrally externally molded using an electrically insulating resin; A signal wire frame 10 having an open end on one side and forming at least one winding around a bead core has a support terminal 14 having a joint seat 15 and an insertion guide portion 17 at the tip, and a signal wire at the tip. A terminal 13 for external lead-out having a terminal 12 for support is attached, and a terminal 1 for support
Insert the insertion guide part 17 at the 4-tip end and the signal line terminal 12 into the bead core 1, and connect the joint seat 15 and the signal line terminal 12 with a flexible printed wiring board 30 provided with a conductive circuit.
They were connected together by soldering or welding, and at least one turn or more of winding was wound around the bead core between the external lead-out terminal 13 and the insertion guide part 17, and then they were integrally molded with an electrically insulating resin 19. A method for manufacturing a small choke coil, characterized in that: the support terminal section, the external lead-out terminal section and the insertion guide section are then cut to remove the required lengths, and the terminals are shaped.

2) Using a bead core 1b with a circular or oval cross section,
Two insertion guide parts 17 formed in the shape of a lead frame
b and two signal line terminals 12b and 12c penetrate into the inner hole of the bead core 1b, and joint seats 15a and 15b are arranged on both sides of the outside of the bead core, and the signal line terminal 12b and the joint seat 15a pass through the bead core inner hole. Each set of joint seats 15b and signal line terminals 12c are connected together using a flexible printed wiring board provided with a conductive circuit, at least one turn of winding is separately formed on a bead core, and electrically insulating resin is used. After integrally molding the exterior, the support terminal 14
, and a method for manufacturing a small choke coil, characterized in that the required lengths of the external lead-out terminal 13 and the insertion guide portion 17 are removed, and the terminals are shaped after cutting.

3) A signal line terminal 12d connected to one external lead-out terminal 13 on a bead core 1c having a circular or oval cross section, and two joint seats 15c on one support terminal 14.

A lead frame is prepared in which an insertion guide portion 17c continuous to 15d and another joint seat 15e are formed, and a signal line terminal 12d, one joint seat 15e, and an insertion guide portion 17c are prepared.
A conductive band is attached to each of the joint seat 15d on the outside of the bead core that penetrates the inner hole of the bead core and connects to the insertion guide portion, the joint seat 15e that passes through the inner hole of the bead core, and the joint seat 15c on the outside of the bead core and the signal line terminal 12d. At least two
Form a round winding into a bead core.

A method for producing a small choke coil, which is characterized in that after integrally molding the exterior with electrically insulating resin, the required lengths of the support terminal 14 and the external lead-out terminal 13 are removed, the terminals are cut, and the terminals are shaped. be.

[Explanation based on examples]

FIG. 2 shows an external perspective view of a small coil according to the present invention,
FIG. 1 is a plan view schematically showing the process flow for manufacturing the small coil of the present invention. FIG. 3 shows a partially enlarged view. FIG. 4 is a diagram showing a bead core, a signal line frame, a flexible printed wiring board, and a temporary fixing film tape used in the present invention. FIG. 5 is a perspective view showing another embodiment according to the present invention.

In FIGS. 3 and 4, the bead core 1 is a small cylindrical ferrite core with an outer diameter of 3 mm, an inner diameter of 2 mm, and a length of 5 mm, and the signal line frame 10 is made of stainless steel, copper, or copper. It is a thin strip-shaped metal plate made of alloy, phosphor bronze, or other conductive alloy that is highly elastic and a good conductor of electricity, and its surface is coated with tin, which is suitable for soldering, or surface treatment such as plating with solder. It is given.

Its shape is such that its base is connected by a reinforcing frame 11, an external lead-out terminal 13 and a signal line terminal 12 connected to the external lead-out terminal 13 are attached perpendicularly to the reinforcing frame 11; Vertical support terminal 14
The support terminal 14 is attached via the joint seat 15 and the positioning part 16, and the insertion guide part 17 is attached in a comb-shaped structure with an open tip.

The temporary fixing film tape 20 is a tape made of polyamide or polyimide-based highly heat-resistant insulating resin coated with an adhesive.

Flexible printed wiring board (hereinafter abbreviated as FPB)
30, a copper foil strip 31 is sandwiched between polyamide and polyimide-based laminate resins 32 to integrally form the required circuit, and has a joint 33 at both ends of which the copper foil strip is exposed, and on the back side. The adhesive is stuck.

Now, to explain the manufacturing method according to FIG. 1, as shown in FIG. 1(A), first, in the later exterior molding process, the portion of the signal line terminal 12 of the signal line frame 10 where the bead core penetrates is placed. Short circuit between terminals due to molding resin pressure,
To prevent pitch deviation, use film tape 20 for temporary fixing.
Paste.

Next, as shown in FIG. 1(B), a plurality of bead cores 1 are aligned and held at a predetermined arrangement pitch using a special jig (not shown), and then the signal line terminals 12 of the signal line frame 10 are
facing the bead core, and inserting the insertion guide part 17 at the tip of the bead core.
into the dedicated jig groove, and while maintaining a predetermined arrangement pitch, insert the bead core 1 into the guide part 17 and the signal line terminal 12.
Next, as shown in FIG. 1(C), an anaerobic adhesive or a heating, room temperature curing adhesive 18 is applied and fixed onto the temporary fixing film tape 20, and the signal is Wire terminal 1
2 and the insertion guide part 17 are inserted into the bead core 1, and are inserted up to the positioning part 16 to be positioned and fixed.

Next, as shown in Figure 1 (D, E), signal line frame 1
Connect the FPB 30 to the signal line terminal 1 so that the joint portion 33 of the flexible printed wiring board (FPB) 30 mentioned above matches between the joint seat 15 at the open end of 0 and the joint line terminal 12.
2 and the joint seat 15, and then the joint seat 15, the signal line terminal 12, and the FPB joint 33 are joined by spot welding or soldering, respectively, as shown in FIG. , the insertion guide portion 17, the joint seat 15, the FPB 30, and the signal line terminal 12, and a single turn of winding is completed in which the inner diameter and outer diameter of the bead core are connected with one conductor.

Next, as shown in FIG. 1(F), the signal line terminal 12, bead core 1, and FPB 30 are integrally sealed and molded with an electrically insulating resin such as epoxy resin, phenol resin, BMC resin, etc. A mold 19 is applied.

Next, as shown in FIG. 1(G), the support terminal 14 is cut and removed, and the external lead-out terminal 13 is cut leaving the required length, separated from the signal line frame, and the external lead-out terminal 13 is cut and removed from the signal line frame. By shaping the terminal 13 and the insertion guide portion, a large number of small choke coils can be obtained simultaneously in large quantities.

In addition, by cutting and removing only the supporting terminal 14 before step (F), and then performing sealing molding in step (F),
It is also possible to eliminate any conductive parts from being exposed on the mold exterior surface.

FIG. 5 shows another embodiment of the present invention, FIG. 5 (al).

In (a2), the bead core 1a has an inner hole with an oval cross-sectional shape, and the insertion guide portion 17a and the signal line terminal 12a are connected at the tip to form an arrowhead shape, so that the lead is shaped to be easily inserted into the bead core 1a. It is a frame. By connecting the joint seat 15 and the signal line terminal 12a using a flexible printed wiring board, a one-turn winding is formed.

Figures 5 (bl) and (b2) use a bead core 1b with an elliptical inner hole and outer eutectoid surface, and a single turn of winding is used.
An example is shown in which a common mode choke coil is formed by winding two circuits around one bead core. The lead frame for forming the winding has an insertion guide section 17b which is made up of two insertion guide sections and has an arrowhead-shaped tip, and two signal line terminals 12b and 12c inside the insertion guide section 17b. It has a structure in which joint seats 15a and 15b are arranged outside the portion 17b.

In FIG. 5 (bl), the joint seat 15a and the signal line terminal 12
b. The joint seat 15b and the signal line terminal 12c are connected by a flexible printed wiring board 30, and the tip of the insertion guide part 17b and the support terminal 14 are connected to the positioning part 16.
By cutting from the part, a common mode choke coil with two circuits of one-turn winding is formed.

5 (cl) and (c2) show a method of forming a two-turn winding in the choke coil manufacturing method according to the present invention. The bead core 1c has an elliptical inner hole and outer eutectoid surface shape, and the bead core inner hole has a signal line terminal 12d,
A joint seat 15e connected to the support terminal 14 and a joint seat 15
The insertion guide portion 17c connected to the bead cores 15c and 15d are inserted, and the joint seats 15c and 15d connected to the support terminal 14 are arranged outside the bead core. In this frame structure, the flexible printed wiring board 30 connects between the joint seats 15d and 15e, and between the joint seat 15c and the signal line terminal 12d, and by cutting the support terminal 14, it is possible to connect to the outside. A choke coil is completed in which the bead core is wound twice between the terminal 13 and the insertion guide portion 17c.

In the embodiment shown in FIG. 5, a bead core having an elliptical outer diameter and an inner diameter is used, but the small coil of the present invention may be formed using a bead core having an outer diameter and an inner diameter of the same shape.

The method for manufacturing a small choke coil according to the present invention has been described in terms of a method for manufacturing a common mode choke in which one winding, two windings, and two circuits of one winding are formed, but by using the manufacturing method of the present invention, , it is possible to manufacture choke coils and common mode choke coils with more turns.

Although the bead core of the present invention has been described using a ferrite bead core as an example and a method for manufacturing a small choke coil, the bead core is not limited to a ferrite bead core. The small choke coil of the present invention can be manufactured by using a bead core formed using a powder core or a powder core made of powder of iron or iron-silicon-aluminum alloy having high magnetic permeability.

〔Effect of the invention〕

As explained above, according to the present invention, the signal wire wound around a small coil is formed into a signal wire frame shape made of thin metal strip, and the signal wire terminal for forming a large number of winding portions is formed into a lead frame shape. However, since the winding portion is formed by joining the joint seat of the lead frame of the signal line and the joint part of the flexible printed wiring board, the manufacturing method of the small choke coil according to the present invention does not require the conventional method. It is possible to omit the winding process and the process of attaching to the bottle terminal, and it is also possible to manufacture a large number of small choke coils at once, and it is easy to automate the insertion and joining process. According to the present invention, a method for manufacturing a small choke coil that is inexpensive and has excellent mass productivity can be provided.

[Brief explanation of the drawing]

FIG. 1 is a plan view schematically showing a process flow for explaining a method for manufacturing a small choke coil according to the present invention. FIG. 2 is an external perspective view of a small choke coil molded with resin according to the present invention. FIG. 3 is an enlarged structural diagram of a small choke coil according to the present invention in which a ferrite bead core is inserted into a frame. FIG. 4 is a diagram showing the configuration of parts used in the manufacturing method of a small choke coil of the present invention, (a) a perspective view of a bead core, (b) a perspective view of a signal line frame, and (C) a temporary fixing film tape. (d) A plan view of a flexible printed wiring board (FPB). FIG. 5 is a diagram showing an embodiment of another small choke coil, and (C2) is a plan view of a lead frame in which the insertion guide part and the signal line terminal are integrated and the tip is shaped like an arrowhead;
1) is a perspective view of a bead core 1a having a circular outer diameter and an elliptical inner diameter inserted into the lead frame of (C2). (bl),
(b2) is a diagram in which a bead core with an elliptical cross section is used to form a common mode choke coil with one turn of winding.
(b2) is a plan view showing the shape of a lead frame forming a winding, and (bl) is a perspective view of a bead core having an oval outer diameter and an elliptical inner diameter inserted into the lead frame of (b2). (cl.
), (C2) is a diagram in which a bead core with an oval cross section is used to form a choke coil with two turns of wire.
FIG. 3 is a plan view of a lead frame forming a winding, and FIG. 3(c) is a perspective view of the lead frame of FIG. FIG. 6 is a perspective view showing the structure of a conventional small choke coil. 1, la, lb, lc...bead core, 2...
・Coated copper wire, end...Storage case, 4...Pin terminal, 5...Top cover, 6...Fixing resin, 7...Terminal,
10... Signal line frame, 11... Reinforcement frame,
12.12a, 12b, 12c, 12d... Signal line terminal, 13... External lead-out terminal, 14... Support terminal, 15.15a, 15b, 15c, 15
d, 15e - joint seat, 16 - positioning part, 17.
17a, 17b. 17c...Insertion guide part, 18...Adhesive, 19.
...Exterior mold, 20...Film tape for temporary fixing, 30...Flexible printed wiring board, 31...
fR foil band, 32... Laminate resin, 33... Joint portion. Patent applicant: Tohoku Metal Industry Co., Ltd. Figure 3 Figure 4 (C) (d) Figure 5 (a2)

Claims (1)

[Claims] 1) In a small choke coil in which a signal wire penetrates a bead core and is integrally sealed and molded using electrically insulating resin, the signal wire is a lead formed from a thin strip-shaped metal plate. The signal line frame 10 has a frame shape and has an open end on one side, and has at least one winding around a bead core.
A supporting terminal 14 having a joining seat 15 and an insertion guide portion 17 at its tip, and an external lead-out terminal 13 having a signal line terminal 12 at its tip are attached. The line terminal 12 is inserted into the bead core 1, and the joint seat 15 and the signal line terminal 12 are connected together by soldering or welding using a flexible printed wiring board 30 provided with a conductive circuit, and the external lead terminal 13 and the signal line terminal 12 are connected together by soldering or welding. Insertion guide part 1
7, at least one turn or more of winding is wound around the bead core, and then integrally molded with electrically insulating resin 19, and then a support terminal section, an external lead-out terminal section, and an insertion guide section are formed. A method for producing a small choke coil, characterized in that the coil is cut to a required length, and then the terminals are shaped. 2) Using a bead core 1b with a circular or oval cross section,
Two insertion guide parts 17 formed in the shape of a lead frame
b and the two signal line terminals 12b and 12c penetrate into the inner hole of the bead core 1b, and joint seats 15a and 15b are arranged on both sides of the outside of the bead core, and the signal line terminal 12b and the joint seat 15a pass through the bead core inner hole, A pair of joint seats 15b and signal line terminals 12c are connected together using a flexible printed wiring board provided with a conductive circuit, and at least one turn of winding is separately formed on a bead core to provide electrical insulation. After integrally exterior molding with plastic resin, support terminal 1
4. A method for manufacturing a small choke coil, which comprises removing the required lengths of the external lead-out terminal 13 and the insertion guide portion 17, cutting the terminals, and shaping the terminals. 3) A bead core 1c with a circular or oval cross section has a signal line terminal 12d connected to one external lead-out terminal 13, and one support terminal 14 has two joint seats 15c, 15d.
Insertion guide part 17c connected to and another joint seat 15
Prepare a lead frame with a shape of e, and connect signal line terminal 1.
2d, one joining seat 15e, and an insertion guide part 17c penetrate into the inner hole of the bead core, and the joining seat 15d on the outside of the bead core that continues to the insertion guide part, the joining seat 15e passing through the inner hole of the bead core, and the joining seat on the outside of the bead core. 15c and the signal line terminal 12d are connected using flexible printed wiring boards 30 each having a conductive band attached thereto.
After forming a turn-wound wire into a bead core and integrally exterior-molding it with electrically insulating resin, the required lengths of the support terminal 14 and the external lead-out terminal 13 are removed, and the terminals are shaped after being cut. A method for manufacturing a small choke coil characterized by: