JP2826320B2 - Three-terminal noise filter and method of manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a three-terminal noise filter of the present invention and a method for manufacturing the same, and more particularly to an improvement in a noise filter formed by winding a strip-shaped conductor and a method for manufacturing the same.

[Prior Art] One or a plurality of strip-shaped conductors formed using aluminum, copper or the like are magnetically or non-magnetically interposed through a dielectric sheet having a high dielectric constant such as Mylar (trade name) or polyethylene. The present inventor has proposed a three-terminal noise filter formed by winding around a winding frame or an air core.
This noise filter has an LC having an inductance in which a stray capacitance (floating capacitance) is distributed over the entire length of the band-shaped conductors involved and between the band-shaped conductors.
It can be used in various fields as a composite part.

This three-terminal noise filter uses a band-shaped conductor. For this reason, a relatively large current can flow, the skin effect on high-frequency signals is minimized, a small size, large inductance and capacitance can be obtained, and workability is good. In addition, it has been confirmed by the inventors that excellent attenuation characteristics can be obtained in this noise filter.

FIG. 7 shows an example of a noise filter using a strip conductor, which has already been proposed by the present invention.

For example, as shown in FIG. 1A, two dielectric sheets 10a and 10b formed using a Mylar tape and two strip-shaped conductors 12 formed using an aluminum foil.
a and 12b are alternately overlapped and wound into a tubular shape. At this time, leads 14a and 14c are connected to the beginning and end of winding of one strip-shaped conductor 12a used as a current-carrying conductor by electric welding or the like. Also, a grounding lead 14b is connected to one end of the other strip-shaped conductor 12b used as a grounding conductor in the same manner.

In the noise filter thus formed, an inductance is formed between the leads 14a and 14c of the conductive strip 12a, and a capacitance is formed between the conductive strip 12c and the ground conductive strip 12c over the entire length of the conductor. Are formed in a distributed constant manner. FIG. 7 (B) shows an equivalent circuit diagram of the noise filter thus formed.

Therefore, the grounding lead 14b is grounded, and the strip-shaped conductor 12a is grounded.
When the leads 14a and 14c are used as input / output terminals, a noise filter having excellent attenuation characteristics over a wide frequency band can be obtained.

[Problems to be Solved by the Invention] In such a noise filter, the three leads 14a, 14b, and 14c may be arranged in a straight line at predetermined intervals as shown in FIG. 8 (A). Required.

If the leads 14a, 14b, and 14c are not aligned, uniform attenuation characteristics and excellent electrical characteristics as a three-terminal noise filter cannot be obtained.

Further, these leads 14a, 14b, 14c must be aligned in a straight line at a predetermined interval, and the lead pitch and the lead arrangement of the printed wiring board to be mounted must be aligned.

If these lead arrangements do not match the hole pitch of the printed wiring board, the leads 14a, 14b, and 14c cannot be inserted into the holes of the printed wiring board to attach a noise filter.

Usually, such a three-terminal noise filter can be manufactured by using an apparatus similar to an apparatus for manufacturing a paper capacitor.

However, using such a device, the three leads 14a, 14b,
The arrangement state of 14c is not constant, and each lead is likely to be shifted as shown in FIGS. 8 (B) and (C). For this reason, it has been extremely difficult to wind up each lead so as to be always in a fixed arrangement state.

In addition, the irregular leads 14a, 14b, 14c must be corrected to a constant pitch after winding, resulting in poor productivity and not suitable for mass production.

[Object of the Invention] An object of the present invention is to provide a three-terminal type noise filter formed in a straight line at predetermined intervals and having excellent mass productivity and attenuation characteristics, and a method of manufacturing the same.

[Means for Solving the Problems] In order to achieve the above object, the invention according to claim 1 includes: a band-shaped conductor having first and second input / output leads connected near both ends; An air-core three-terminal noise filter wound with a grounding strip-shaped conductor connected to a grounding outer lead near an end thereof via a dielectric sheet, wherein the first inner lead and the first The respective outer leads are tied in a state where the outer leads are displaced by 1/4 turn, and the first outer lead and the grounding outer lead are close to each other on the circuit arrangement and are displaced by about 1/2 turn. The wound body is pressed flat from a direction perpendicular to a straight line, and the first inner lead, the first outer lead, and the grounding outer lead are formed so as to be aligned on a straight line at substantially equal intervals. I do.

The invention according to claim 2 of the present invention provides a laminated body formed by laminating at least two strip-shaped conductors via a dielectric sheet, and a first inner lead for input and output near the inside of the first strip-shaped conductor. Connecting the laminate to a plurality of turns around a rotary winding axis and displacing the first inner lead by 1/4 turn near the outside of the first belt-shaped conductor, and the first outside for input and output. Leads are connected, and near the outer end of another strip-shaped conductor,
Connecting the grounding outer lead to the outer lead in the vicinity of the first outer lead and displacing the first outer lead by 1/2 rotation about the winding axis, removing the rotary winding axis from the wound laminate, and removing each of the outer leads Pressing the laminated body from a direction perpendicular to the straight line to be connected to form a flat shape in which each lead is aligned in a straight line at substantially equal intervals, wherein the first inner lead and the first outer lead are used as input / output terminals. The outer lead for grounding is a ground terminal.

[Operation] Next, the operation of the present invention will be described.

(A) As shown in FIG. 2, the three-terminal type noise filter of the present invention includes a first inner lead 34-1 for input and output and a first outer lead 34-2 near both ends of the strip-shaped conductor 30-1. And other strip-shaped conductors, that is, a strip-shaped conductor 30- for grounding.
A grounding outer lead 36 is connected to the vicinity of the outer end 2.

Each of the strip-shaped conductors 30-1 and 30-2 is wound into a flat tubular shape via dielectric sheets 32-1 and 32-2.

One of the first inner lead 34-1 and the first outer lead 34-2 is used as an input terminal, the other is used as an output terminal, and the ground outer lead 36 is used as a ground terminal.

By doing so, the three-terminal noise filter of the present invention functions as a distributed constant type noise filter shown in FIG.

(B) By the way, according to the filter manufacturing method of the present invention, the plurality of strip-shaped conductors 30-1 and 30-2 are combined with the dielectric sheet 32.
As shown in FIG. 4 (A), the laminated body superposed through -1, 32-2 is wound around the rotary winding shaft 38 a plurality of times, and substantially in a straight line through the center P of the winding shaft 38. The outer leads 34 of the respective strip-shaped conductors 30-1 and 30-2 are located at
−2,36 are connected.

Then, remove the rotating winding shaft from the wound laminate,
As shown in FIG. 4 (B), the laminate is pressed by a method orthogonal to the straight line connecting the outer leads 34-2, 36 so that the leads 34-1, 34-2, 36 are substantially straightened. It is formed into a flat shape aligned on a line.

Thus, according to the method of the present invention, each lead 34
-1,34-2,36 can be formed so as to be always on a straight line, so that the damping characteristics are almost uniform, the mass productivity is excellent, and ringing is less likely to occur.
A terminal type noise filter can be made.

Furthermore, in accordance with the present invention, each of the leads
The intervals of 34-2, 34-1, and 36 can be made equal intervals, whereby a noise filter that can be easily attached to a substrate can be obtained.

(C) In this type of noise filter provided with a ground lead, the closer the first outer lead 34-2 and the outer ground lead 36 are to each other in the circuit arrangement, the more the noise filter becomes. The present inventor has found that the attenuation characteristics are good.

The inventor of the present invention arranges the first outer lead 34-2 and the grounding outer lead 36 at positions shifted by about 1/2 rotation, thereby winding these outer leads 34-2 and 36 around the winding shaft. It is located on a straight line including the center.

By doing so, the noise filter of the present invention can reduce the lead interval between the ground outer lead 36 and the first outer lead 34-2 when the belt-shaped conductors 30-1 and 30-2 are developed, by the first distance. The distance between the inner lead 34-1 and the first outer lead 34-2 can be reduced to at least a few percent of the lead interval, and good attenuation characteristics can be obtained.

EXAMPLES Next, preferred examples of the present invention and comparative examples will be described with reference to the drawings.

Embodiment FIG. 1 shows a comparative example of a three-terminal noise filter studied by the applicant.

When manufacturing the noise filter of the comparative example, as shown in FIG. 2, the strip-shaped conductor 30-1 and the grounded strip-shaped conductor 30-2 are overlapped via the dielectric sheets 32-1 and 32-2. Together with this, a laminated body is formed, and a first inner lead 34-1 for input / output is connected near the inner end (the left end in the figure) of the strip-shaped conductor 30-1.

Next, as shown in FIG. 1 (A), the laminate is wound around the rotary winding shaft 38 a plurality of times.

A first outer lead 34-2 for input / output is connected near the outside of the strip-shaped conductor 30-1, and the grounded strip-shaped conductor 30-2 is connected.
The grounding outer lead 36 is connected near the outer end of the first outer lead 34-2 while being shifted by 1/2 rotation about the winding shaft 38 from the first outer lead 34-2.

By doing so, the distance between the leads 34-2 and 36 in a state where the conductors 30-1 and 30-2 are expanded can be made sufficiently close to each other, and as described later, a noise filter having excellent attenuation characteristics can be obtained. Can be obtained. Further, the two leads 34-2 and 36 can be positioned at a predetermined interval on the substantially straight line 100 via the winding shaft center P.
It is possible to obtain a noise filter which is substantially uniform and has good attenuation characteristics and is excellent in mass productivity.

Next, in the present comparative example, after the end of the winding of the winding portion 40 is fixed by heat welding or an adhesive, the winding portion 40 is removed from the winding shaft 38, and a wire 100 connecting the outer leads 34-2 and 36 is formed. The winding part 40 is pressed while being heated from a direction perpendicular to the direction.

As a result, as shown in FIG. 1 (B), the winding portion 40 is deformed at the air core portion 42 removed from the winding shaft 38, and
34-2, 34-1, and 36 are arranged in a straight line (inline), and the interval between the leads is increased.

By doing so, the noise filter of this comparative example has a substantially flat winding portion 40 as shown in FIG.
And three in-line leads 34-2, 34-1 and 36 provided on one end surface thereof.

The noise filter may be provided with a casing on the outer surface of the winding part 40 with metal foil or the like, or with a coating of epoxy or the like, as necessary.

As described above, in the three-terminal noise filter of the comparative example, the leads 34-2, 34-1, and 36 can be reliably arranged in a straight line (in-line). Therefore, the noise filter can be easily mounted on the substrate, and can sufficiently withstand external physical stress. In addition to this, according to the comparative example examined by the applicant, the intervals between the leads can be always formed to be constant, so that the variation in the attenuation characteristics of the manufactured noise filter is reduced.

Therefore, according to the comparative example, it is possible to mass-produce a noise filter that has substantially uniform attenuation characteristics and can be made sufficiently small.

In the comparative example shown in FIG. 1, the winding portion 40 in which the leads 34-1, 34-2, and 36 are arranged on the straight line 100 in advance as shown in FIG. ).

However, in such a structure, for example, as shown in FIG.
(A)
(B) and (C) in FIG.
As shown in FIG.
Will shift. As a result, a bulge occurs around the center lead 34-1 at a position shifted to one lead side as viewed from the center of the winding shaft, and the completed filter may have a shape that is asymmetrical left and right when viewed from the center P of the winding shaft. Many.

FIG. 4 shows a preferred embodiment of the present invention which solves such a problem.

As shown in FIG. 4 (A), a straight line 1 orthogonal to the straight line 100
As shown in FIG. 1B, the wound portion 40 having the first inner lead 34-1 disposed on the top 10 is crushed flat as shown in FIG. A noise filter in which the intervals between 34-1 and 36 are equal can be formed.

This makes it easier to attach the noise filter to the printed circuit board.

In particular, according to the filter of this embodiment, for example, as shown in FIG. 4 (B), three leads are formed so as to be aligned at substantially equal intervals on a straight line. For this reason, when the laminate shown in FIG. 3A is pressed flat, the position of the center lead becomes the same position as the winding center P. As a result, FIG.
As shown in (C), the three-terminal noise filter is formed substantially symmetrically with respect to the center P of the winding shaft.

As described above, according to the present embodiment, there is no inconvenience that the finally formed filter is formed asymmetrically left and right when viewed from the center of the winding shaft, and a good three-terminal noise filter can be obtained. .

Next, the attenuation characteristics of the noise filter of the present invention will be discussed.

The present inventors changed the relative position of the grounding outer lead 36 with respect to the first outer lead 34-2 in the developed view of the strip conductors 30-1 and 30-2 shown in FIG. −
An experiment was conducted on how the 2,36 relative relationships affect the operation of the noise filter, that is, the attenuation characteristics.

Experiments for examining the effects of the present invention included various strip-shaped conductors.
30-1 and 30-2 are 60 cm in length, 10 mm in width, and 50 μm in thickness using aluminum foil.Dielectric sheets 32-1 and 32-2 are 12 mm in width and 25 μm in length using Mylar tape. The leads 34-1, 34-2, and 36 used were 0.8 mm in diameter.

As shown in FIG. 13A, the first inner lead 34-1 of the strip-shaped conductor 30-1 is located at a position 5 cm from the start of winding (left end), and the distance between the inner lead 34-1 and the outer 34-2 is set. 40 cm and the total number of turns is 25.

Next, as shown in FIG. 4B, the grounding outer lead 36 moves the position corresponding to the first outer lead 34-2 (A) and the position shifted 2 cm in the direction of the inner lead 34-1. (B), an intermediate position between both leads 34-1 and 34-2 is (C), and a position corresponding to the first inner lead 34-1 is (E).

As a result of this experiment, the inventor found that the first outer lead 34-1
Alternatively, it has been found that the closer the ground lead 36 is arranged to the first inner lead 34-1, the better the attenuation characteristic of the noise filter is.

That is, the attenuation characteristic of this filter sample is the fifth.
As shown in the figure, the grounding outer lead 36 is connected to the outer lead 34-2,
Position (A) corresponding to each of the inner leads 34-1,
When provided in (E), it is extremely good, but when provided in positions (B) and (C) away from it, the degree of attenuation is low, and it is not practical.

However, if the grounding outer leads 36 are provided at the positions shown in FIGS.
-1 or the outer leads 34-2 face each other via the thin dielectric sheet 32, so that a sufficient physical spacing cannot be obtained, and there is a danger of short-circuiting due to wiring and soldering operations. Do not offer.

Therefore, the present inventor, as shown in FIG. 2C, sets the ground lead 36 to the first outer lead 34-2 (A).
The attenuation characteristics of the samples arranged at each of the positions (a) to (e) at 0.5 cm intervals based on the position (a) were examined.

As a result, the attenuation characteristics shown in FIG. 6 were obtained. That is, the position of the grounding outer lead 36 is the first outer lead 34-
The maximum attenuation characteristic is obtained at the position (A) that overlaps with 2, and the degree of attenuation decreases as the position deviates from this position. Even if the ground outer lead 36 is shifted to any side of the first outer lead 34-2, that is, the ground outer lead 36 is shifted earlier or later than the first outer lead 34-2. There is virtually no difference.

In accordance with the above characteristics found by the present inventor, the noise filter of the present invention is configured such that the first outer lead 34-2 and the outer ground lead 36 are arranged with their rotational positions shifted from each other by a half turn of the winding shaft 38. I have. By doing so, in the noise filter of the present invention, both leads 34-2 and 36 come close to each other, and excellent attenuation characteristics can be obtained.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

For example, when it is desired to increase the inductance of the coil L1 as the noise filter of the present invention, a magnetic core may be used at the center of the winding part 40, or a magnetic conductor may be used as the band-shaped conductor. . Further, in the above-described embodiment, the laminated body formed using the two strip-shaped conductors 30-1 and 30-2 and the two dielectric sheets 32-1 and 32-2 has been described as an example. The invention is not limited to this. For example, three or more strip-shaped conductors and three or more dielectric sheets may be provided, and two of the strip-shaped conductors may be provided with leads.

[Effects of the Invention] As described above, according to the present invention, the positional relationship between the first outer lead of the strip-shaped conductor and the grounding outer lead of the grounding strip-shaped conductor is determined by winding each of these strip-shaped conductors. 1 / in the direction
By displacing the position by two rotations and arranging the first outer lead and the grounding outer lead on an extension including the center of the winding shaft, a three-terminal noise filter having excellent attenuation characteristics can be obtained.

Furthermore, according to the present invention, since each lead can be arranged at a constant interval on a straight line including the center of the winding axis,
It is possible to obtain a noise filter that is substantially uniform, has good attenuation characteristics, and is excellent in mass productivity. Therefore, there is an effect that problems that must be considered in manufacturing such a noise filter, such as problems of non-uniform characteristics and low yield, can be solved.

Further, according to the present invention, there is no inconvenience that the finally formed filter is formed left and right asymmetrically as viewed from the center of the winding shaft, and a good three-terminal noise filter can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a comparative example of the noise filter of the present invention, FIG. 2 is an explanatory diagram of a laminated body used for the noise filter of the embodiment, and FIG. 3 is an equivalent circuit of the noise filter of the embodiment. FIG. 4, FIG. 4 is an explanatory diagram of a preferred embodiment of the noise filter of the present invention, FIG. 5, FIG. 6 is a special attenuation diagram of the noise filter of the present invention, FIG. 7, FIG. FIG. 30-1 band-shaped conductor 30-2 band-shaped grounding conductor 32-1, 32-2 dielectric sheet 34-1 first inner lead 34-2 first outer lead 36 … Outer ground lead 38 …… Wind shaft 40 …… Wound part

Claims (2)

(57) [Claims] 1. A band-shaped conductor having input / output first inner leads and first outer leads connected near both ends, and a grounded band conductor connected to a grounding outer lead near outer ends. An air-core type three-terminal noise filter wound around a dielectric sheet, wherein the first inner lead and the first outer lead are shifted by 1/4 turn, and the first outer lead is further shifted. And, in a state where the grounding outer leads are close to each other on the circuit arrangement and shifted by about 1/2 rotation, the pressed rolled body is pressed flat from a direction orthogonal to a straight line connecting the outer leads, An air-core type three-terminal noise filter, wherein a first inner lead, a first outer lead, and a grounding outer lead are formed so as to be aligned in a straight line at substantially equal intervals. 2. A laminated body is formed by laminating at least two strip-shaped conductors via a dielectric sheet, and a first inner lead for input / output is connected near the inside of the first strip-shaped conductor. And a step of winding the laminate around a rotary winding axis a plurality of times, and connecting the first inner lead near the outside of the first strip-shaped conductor.
Connect the 1st outer lead for input and output by shifting by 1/4 turn,
And near the outer end of the other strip-shaped conductor, a step of connecting the grounding outer lead to be closer to the first outer lead in circuit arrangement and shifted by 1/2 rotation from the first outer lead about the winding axis, Removing the rotary winding shaft from the wound laminate, pressing the laminate from a direction perpendicular to the straight line connecting the outer leads, and forming each lead into a flat shape in which each lead is arranged in a straight line at substantially equal intervals; A method for manufacturing a three-terminal noise filter including the first inner lead and the first outer lead as input / output terminals and the grounding outer lead as a ground terminal.