JP2579483B2 - Signal line filter and method of manufacturing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal line filter with lead terminals mounted on a circuit board of a digital electronic device, and a method of manufacturing the same.

<Conventional technology> With the digitization and speeding up of signals handled by electronic devices, etc., protection measures against signal interference and malfunction due to unnecessary radiation noise generated or received between the signal line and the power supply line are required. is important. As one of these measures, a signal line filter having a structure in which a signal line is made to pass through a hollow of a compacted ring core made of a magnetic material and a ferrite ring core, and a signal line is known as a means for exhibiting an effective unnecessary radiation noise effect. ing.

Conventionally, when this type of signal line filter is directly mounted on the circuit board of an electronic device, considering the fact that the number of signal lines handled by the electronic device is very large, the ring core that penetrates each signal line is small. Need to be The use of a large number of small ring cores complicates the mounting operation.

Under such circumstances, an element-type signal line filter has been proposed and put into practical use. This element type signal line filter is composed of a container having an opening made of a molded article of an electrically insulating resin, and external terminals (a plurality of terminals) made of a good conductor metal implanted so that the ends are exposed inside and outside the container. And the insulating core is peeled off and wound around the end of the external terminal that penetrates through the hole of the accommodated ring core and that is exposed in the container. A conductive wire to be soldered, and an outer lid made of a molded product of an electrically insulating resin fixed with an adhesive so as to close the opening of the container.

<Problems to be Solved by the Invention> However, assuming that the conventional element-type signal line filter corresponds to the circuit board of the electronic device by itself, the number of external terminals is reduced on the circuit board of the electronic device. The number of signal lines must be the same, and if there are many signal lines, the hole of the ring core must be enlarged, and the size of the ring core itself also increases. In addition, the increase in the size of the ring core increases the length of the magnetic path, thereby deteriorating the effect of absorbing unnecessary radiation noise.

Considering the manufacturing process of the conventional element type signal line filter, the operation of peeling off the film at the end of the conductor and the operation of winding it around the external terminal are very complicated. Further, it is difficult to mechanize and automate such operations.

Therefore, there is a demand for an element-type signal line filter that is small in size, has an excellent effect of absorbing unnecessary radiation noise, has high productivity, and can be manufactured and automated.

It is an object of the present invention to be small in size, excellent in absorbing unnecessary radiation noise, easy to manufacture, and mechanized in manufacturing.
An object of the present invention is to provide a device-type signal line filter that can be automated.

Another object of the present invention is to provide a method of manufacturing a signal line filter that can be manufactured with high productivity and that is small in size and excellent in absorbing unnecessary radiation noise.

<Means for Solving the Problems> According to the present invention, a plurality of thin lead terminal pieces extending in one direction are included, and the lead terminal pieces have a circuit of an electronic device at an outer end in the extending direction. A lead terminal made of a good conductive material having the same interval as the terminal arrangement pitch of the circuit pattern for signal lines on the substrate, and forming a tapered portion converging toward the center of the arrangement at the center in the extending direction; A signal line filter comprising a magnetic core made of a high-magnetic material and formed integrally with a predetermined area of the lead terminal piece so as to cover the tapered portion as a center.

According to the present invention, the magnetic core may be any one of a ferrite material having a low-temperature sintering property and a mixed material of a ferrite material and an insulating resin having a mixing ratio of the ferrite material of at least 30% or more. The signal line filter comprising one of the above is obtained.

According to the present invention, there are further provided two thin strip-shaped plates made of a good conductive material and arranged in parallel with each other, and a plurality of thin lead terminal pieces provided so as to bridge therebetween. Is the same interval as the terminal arrangement pitch of the circuit pattern for the signal line on the circuit board of the electronic device at the outer end of the bridge, and forms a tapered portion converging toward the center of the line at the center of the bridge A step of obtaining a lead frame by punching, and covering a predetermined region of the lead terminal piece of the lead frame with a powder magnetic material made of a high magnetic material around the tapered portion. Forming a core and cutting an outer end of the lead terminal piece exposed outside the magnetic core to extract a signal line filter in which the lead terminal piece and the magnetic core are integrated from the lead frame; Engineering Manufacturing method of a signal line filter characterized by having the door is obtained.

According to the present invention, the powder magnetic material used in the step of forming the magnetic material core is a ferrite material having a low-temperature sintering property, and a mixing ratio of the ferrite material is at least 30% or more. A method for manufacturing the signal line filter, wherein the method comprises one of a mixture of a ferrite material and an insulating resin.

<Operation> Since the magnetic core made of the powder magnetic powder is closely attached to and integrated with the lead terminal piece, the magnetic gap is extremely small and the magnetic leakage is small. In addition, the length of the magnetic path formed around the tapered portion at the center of the lead terminal piece is short, and the effect of absorbing unnecessary radiation noise is excellent.

Embodiment Hereinafter, a signal line filter and a method of manufacturing the same according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an external perspective view showing a signal line filter according to an embodiment of the present invention, FIG. 2 is an external perspective view showing a part of a lead frame used in the present invention, and FIG.
FIGS. 2C to 2C are plan views showing the respective steps side by side on the lead frame for convenience of explanation of the manufacturing steps of the present invention.

In FIG. 1, the present signal line filter has a structure in which a lead terminal 3 and a magnetic core 1 are integrated. Hereinafter, the present signal line filter will be described in detail by describing a method of manufacturing the signal line filter.

In FIG. 2, the lead frame 2 is made of stainless steel,
Rich in elasticity such as iron, beryllium copper or their alloys,
It is a highly conductive strip-shaped metal plate. The surface of the lead frame 2 is subjected to a surface treatment so that the soldering is reliably performed. In particular, when electrical insulation is required, it is preferable to further form an insulating coating by insulating coating or the like.

The lead frame 2 is manufactured by precision punching or photo-etching at regular intervals in the longitudinal direction. The lead frame 2 is provided so as to bridge between two narrow positioning frames 21 arranged in parallel at both ends, a bridging frame 22 for keeping them parallel, and a bridge between the two positioning frames 21. Provided (seven in this example) thin lead terminal pieces 23 and 25. The lead terminal pieces 23 and 25 constitute a tapered portion 24 which is converged toward the center of the bridge at the same interval as the terminal arrangement pitch of the signal line circuit pattern on the circuit board of the electronic device and at the center of the bridge. ing. However, lead terminal strip 2
Between the points 3 and 25, a predetermined insulation distance is ensured not only outside the bridge but also at the center of the bridge constituting the tapered portion 24. Also, a group of lead terminal pieces 23 and 25 is a reinforcing frame extending in parallel with the positioning frame 21.
It is erected and connected by 27. Further, the positioning frame 21 is provided with a positioning hole 26 used for transporting the lead frame 2. In addition, lead frame 2
To the two positioning frames 21 and 2 as shown in FIG.
By forming one section defined by the bridge frame into a tape shape having several thousands to several tens of thousands of sections, it is convenient when the manufacture of the signal line filter is mechanized or automated.

Now, the lead frame 2 in the state shown in FIG.
While being accurately positioned with reference to the positioning hole 26, is transported and placed in an integrated molding press die (not shown).

Then, as shown in FIG. 3 (b), a predetermined amount of the powder magnetic material powder charged into the press for integral molding is filled in a press die, and the lead terminal pieces 23 and 25 are wrapped. The magnetic core 1 is formed.

Next, the lead frame 2 in the state shown in FIG.
Is transported and arranged in a frame punching press, and the lead terminal pieces 23 and 25 are cut inside the reinforcing frame 27 (indicated by a reference numeral CP) as shown in FIG. 3 (c).
Thereby, a signal line filter in which the lead terminal pieces 23 and 25 (the lead terminal 3 in FIG. 1) and the magnetic core 1 are integrated is extracted from the lead frame 2. During this process (simultaneously with cutting) or after that,
By bending 23 and 25 downward, the shape of the lead terminal 3 shown in FIG. 1 is obtained.

The powder magnetic material used for this kind of magnetic core is preferably formed of a ferrite material having a low-temperature sintering property or an insulating material containing at least 30% or more of the ferrite material in a mixing ratio.

<Effects of the Invention> As described above, in the signal line filter according to the present invention, since the magnetic core is integrally formed so as to completely surround the lead terminal for the signal line without a gap, the signal line filter and the magnetic core are Since there is almost no gap and the lead terminal is tapered at the center of the magnetic core, the magnetic path length is short, so that the leakage magnetic flux is small and the magnetic circuit efficiency is good.

Also, regarding the manufacturing process, unlike the conventional one in which the signal line is penetrated into the hole of the magnetic ring core, the signal line is formed integrally with the magnetic core around the signal line. There is no troublesome work such as passing through the hole, peeling off the insulating coating of the signal line terminal, and connecting the external terminal to the signal line.

That is, the signal line filter according to the present invention is compact, has an accurate terminal arrangement, has an excellent effect of absorbing unnecessary radiation noise, is easy to manufacture, and can be manufactured to be mechanized and automated.

Further, the method for manufacturing a signal line filter according to the present invention can manufacture a small-sized signal line filter having an excellent effect of absorbing unnecessary radiation noise with high productivity.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a signal line filter according to the manufacturing method of the present invention, FIG. 2 is an external perspective view of a part of a lead frame used in the signal line filter of the present invention, and FIG. FIG. 3 is a plan view showing steps of a manufacturing method using the lead frame of FIG. 2. FIG. 3A shows a part of a strip-shaped cut lead frame, and FIG. 3B shows a state where a magnetic core is formed by pressing a magnetic powder on the lead frame. FIG. 3 (c) shows a state in which the state of FIG. 3 (b) is cut while leaving the reinforcing frame and the lead terminal pieces. In the drawing, reference numeral 1 denotes a magnetic core, 2 denotes a lead frame, 3 denotes a lead terminal, 21 denotes a positioning frame, 22 denotes a bridging frame, 23 and 25 denote lead terminal pieces, 24 denotes a tapered portion, 26 denotes a positioning hole, and 27 denotes a positioning hole. It is a reinforcement frame.

Claims (4)

(57) [Claims] 1. A circuit for a signal line on a circuit board of an electronic device including a plurality of thin lead terminal pieces 23 and 25 extending in one direction, the lead terminal pieces 23 and 25 being provided at outer ends in the extending direction. A tapered portion that has the same interval as the pattern arrangement pitch of the pattern and is converged toward the center of the line at the center in the extending direction
A lead terminal 3 made of a good conductive material constituting 24, and a high magnetic material formed integrally with a predetermined area of the lead terminal pieces 23 and 25 so as to cover the tapered portion 24 as a center. A signal line filter comprising a magnetic core 1. 2. The magnetic core 1 according to claim 1, wherein the ferrite material has a low-temperature sintering characteristic and a ferrite material having a mixing ratio of the ferrite material of at least 30% or more and an insulating resin. 2. The signal line filter according to claim 1, wherein said signal line filter comprises one. 3. A lead terminal comprising two thin strips made of a good conductive material and arranged in parallel with each other, and a plurality of thin lead terminal pieces 23 and 25 provided so as to bridge therebetween. The pieces 23 and 25 are at the same interval as the terminal arrangement pitch of the signal line circuit pattern on the circuit board of the electronic device at the outer end of the bridge, and are focused toward the center of the arrangement at the center of the bridge. Obtaining the lead frame 2 forming the tapered portion 24 by punching;
Forming a magnetic core 1 by covering a predetermined region of the lead terminal pieces 23 and 25 with a powder magnetic material made of a high magnetic material around the tapered portion 24; (1) cutting the outer ends of the lead terminal pieces 23 and 25 exposed outside to extract a signal line filter in which the lead terminal pieces 23 and 25 and the magnetic core 1 are integrated from the lead frame 2; A method for manufacturing a signal line filter, comprising: 4. The compacted magnetic material used in the step of forming the magnetic material core 1 is a ferrite material having a low-temperature sintering property and a ferrite material having a mixing ratio of the ferrite material of at least 30% or more. 4. The method for manufacturing a signal line filter according to claim 3, wherein the method is made of one of a mixture of a material and an insulating resin.