JPH0376004B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a bead inductor in which ferrite beads are attached to a radial lead wire.

A conventional bead inductor has a shape as shown in the first diagram. That is, a cylindrical ferrite bead 2 was inserted into approximately the center of the axial lead wire 1 and fixed with an adhesive. In manufacturing this, as shown in Figure 2,
Adhesive 3 is placed approximately in the center of the axial lead wire 1.
was applied in the form of a bead, and the ferrite bead 2 was inserted from one end of the lead wire 1 so that the adhesive 3 was adhered to the inner wall surface of the lead wire 1, and then the adhesive 3 was cured. However, in this conventional method, the adhesive 3 must be applied to the approximate center of the axial lead wire 1 by a drip method, a brush painting method, etc., so it is difficult to make the amount of adhesive applied uniform. This had the disadvantage that it was difficult to stably adhere the beads 2. In addition, with these methods, if too much adhesive is applied, the adhesive will flow to the lead wires and be applied to unnecessary areas, worsening the solderability when attaching to printed circuit boards, etc., which will be described later. It had drawbacks.

Furthermore, it has been conventionally practiced to apply the adhesive continuously, but this results in unnecessary adhesive being applied to the lead wires, causing trouble in soldering the lead wires as described above, and There was also a large amount of material loss for the adhesive, making it less economical.

Furthermore, in the above adhesive application methods,
In consideration of workability, one-component quick-curing adhesives and cyanoacrylate-based instant adhesives are commonly used, but these are very expensive.
They were forced to increase the cost of their products.

As mentioned above, in the conventional method, ferrite beads are inserted through an axial lead wire coated with adhesive, so the stress of the adhesive acts when inserting the beads, ensuring that the beads are positioned in the specified position. It was difficult, had low work efficiency, and was not suitable for mass production.

Furthermore, when attaching such a conventional axial lead type bead inductor to a printed circuit board, etc., as shown in FIG. Although soldering is carried out by inserting the ferrite beads 2, the entire length of the ferrite beads 2 occupies the surface of the board 4, which has the disadvantage of hindering the miniaturization of the board 4 and the set. For example, if a large inductance is required depending on the application, it is common practice to increase the size (longer length) of the bead 2. had become even larger, making it even more unsuitable for miniaturization.

The present invention has been made in an attempt to eliminate the above-mentioned drawbacks, and after a ferrite bead is inserted into at least one leg of a U-shaped lead wire, which has a pair of legs protruding in the same direction from both ends of the base. U
The base side of the U-shaped lead wire is immersed in an adhesive, leaving at least the vicinity of the upper end of the ferrite beads, and then pulled up, and then the adhesive attached to the U-shaped lead wire and the ferrite beads is cured. The present invention relates to a method of manufacturing a bead inductor characterized by the following. In other words, the present invention attempts to construct a bead inductor as a radial lead type.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 is a side view showing a series of manufacturing steps.
First, a U-shaped lead wire 11 having a pair of legs protruding from both ends of a base in the same direction is prepared.

Next, both legs 11a, 11 of this lead wire 11
The ferrite beads 12a, 12b are inserted into the wire 12b from their respective free ends so that the lower ends of the beads 12a, 12b are brought into contact with the base 11c of the lead wire 11.

Next, each free end of the U-shaped lead wire 11 is held by a holding body 13 made of a material such as paper, resin, metal, etc. by adhesive, fitting, pressure bonding, or the like.

Next, the lead wire 11 held by the holder 13 in this way is coated with the adhesive paint 14 from the base 11c side.
The adhesive 14 adhering to the lead wire 11 and beads 12a and 12b is cured by immersing it in the liquid and pulling it out. In this case, the immersion depth of the lead wire 11 is determined by the bead 1 installed on the base 11c side.
2a and 12b must not all be buried in the paint 14. This is to prevent the adhesive 14 from adhering to the legs 11a, 11b of the lead wire 11. This immersion depth is preferably about 3/4 to 1/2 of the length of the beads 12a, 12b. However, if the concentration of the adhesive paint 14 is appropriately selected and used, as shown in FIG. The immersion depth can be selected arbitrarily to obtain a strong adhesive force.

In this way, a bead inductor manufactured according to the present invention is obtained, but when actually attaching it to a printed circuit board (not shown), etc., for example, connect the lead wire 11 with the broken line in FIG. The holder 13 is removed by cutting at the indicated portions, and the free ends of both leg portions 11a and 11b of the lead wire 11 are inserted into holes in the board and soldered.

FIG. 6 shows another example of the shape of the U-shaped lead wire 11 used in the present invention.
There is a small bent part 15 near the base 11c of a, 11b.
a and 15b are formed in advance, and the bent portions 15a and 15b are brought into contact with the inner wall surface of the ferrite bead to be inserted and mechanically locked. If such a lead wire 11 is used, it is convenient because the beads will not move during handling until they are bonded with an adhesive.

FIG. 7 shows another example of the shape of a bead inductor manufactured according to the present invention, in which a ferrite bead 12 is attached to one leg 1 of a U-shaped lead wire 11.
It is attached only to 1a. In this example, lead wire 1 has no beads attached.
A bent protrusion 16 that almost matches the height of the bead is formed on the leg portion 11b of 1, but when this bead inductor is mounted on a printed circuit board etc., the leg portion 11b to which no beads are attached 11b
This is intended to prevent the substrate from penetrating too much into the hole of the substrate and causing it to tilt. Note that the shape of the bent protrusion 16 is arbitrary; for example, the bent protrusion 16 may be formed by attaching another member to the protrusion without bending it.
Moreover, these protrusions are not necessarily essential. The remaining points are the same as in the previous example, so their explanation will be omitted.

Note that the drawings and the above-mentioned embodiments are for embodying the present invention, and are not limited to these in any way, and various design changes, material changes, etc. may be made from the spirit of the present invention. That's easy to understand. For example, when dipping the U-shaped lead wire 11 into the adhesive paint 14, it is not necessarily necessary to hold the free end of the lead wire 11 in the holder 13.

As described above, in the present invention, the bead inductor is a radial lead type, and the beads are fixed to the lead wire by dipping in an adhesive paint, pulling it up, and curing, so it is excellent in mass production and extremely easy to handle. It has a hardening that becomes.
Further, in the present invention, since the adhesive does not unnecessarily adhere to the lead wire, it is possible to achieve good solderability to a printed circuit board or the like. In addition, in the present invention, by making the bead inductor a radial lead type, the space it occupies on a printed circuit board etc. can be extremely small, making it ideal for downsizing. It becomes much better. Also, if you want to increase the inductance value, you can easily do it by attaching ferrite beads to both legs of the lead wire, but it requires almost no new space and is more compact. It will be suitable for Furthermore, in the present invention, since the beads are attached to the base of the U-shaped lead wire, the beads can be positioned stably and reliably, and the characteristics can always be uniform. In addition, in the present invention, beads are fixed by dipping them in an adhesive paint, so there is no need to use expensive instant adhesives as in the past, and materials can be selected from the viewpoint of workability and pot life. This invention has many effects, such as being able to be applied over a wide range of areas and also allowing the use of inexpensive products.

[Brief explanation of drawings]

Fig. 1 is a side view of a conventional bead inductor, Fig. 2 is a perspective view showing part of its processing steps, Fig. 3 is a side view showing the state in which it is attached to a substrate, and Fig. 4 is a side view of the bead inductor of the present invention. FIG. 5 is a side view showing an example of the manufacturing process, FIG. 5 is another example showing a part of the manufacturing process of the present invention, and FIG. 6 is a side view showing another example of the U-shaped lead wire used in the present invention. , FIG. 7 is a side view showing another example of a bead inductor manufactured according to the present invention.

Claims (1)

[Claims] 1. After inserting a ferrite bead into at least one leg of a U-shaped lead wire that has a pair of legs protruding in the same direction from both ends of the base, insert the base side of the U-shaped lead wire into at least the upper end of the ferrite bead. A method for manufacturing a bead inductor, which comprises immersing the lead wire in an adhesive and pulling it up, leaving the vicinity of the lead wire, and then curing the adhesive adhering to the U-shaped lead wire and the ferrite beads.