JPH01316013A - Noise filter - Google Patents

Abstract

PURPOSE:To improve the productivity through the shortening in assembling time and to miniaturize a filter by forming a noise filter by having only to wind 1st and 2nd insulation sheets together with each conductor. CONSTITUTION:Long insulation films 12, 14 such as a polyester film are prepared and aluminum or copper conductor foils 16, 18 are adhered to the upper face continuously in a longitudinal direction. Then other conductor foil 20 is subjected to spot welding to both ends and they are used as 1st terminals 22a, 22b and 2nd terminals 24a, 24b. Then the sheets 12, 14 are overlapped and in this case, they are overlapped in a way that the upper face of the sheet 14 is directed inside and the sheets 12, 14 are wound cylindrically together with the conductor foils 16, 18. Then a jumper is fitted respectively to both side of the cylinder 28 obtained in this way to constitute the equivalent circuit of the noise filter.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a noise filter, in which inductors are connected between input and output terminals like a line filter, and capacitors are connected between input and output terminals. Regarding the noise filter that is connected.

[Prior art]

This type of line filter or noise filter has conventionally been made by assembling a plurality of discrete components such as capacitors and inductors, as shown in the circuit diagram of FIG.

[Problem that the invention seeks to solve]

Conventional noise filters require time to assemble, resulting in low productivity, and therefore there is a limit to cost reduction. Also, since it is made by assembling discrete parts,
Conventional noise filters could not be made smaller.

Therefore, the main objective of this invention is to provide a noise filter that is smaller and cheaper.

[Failure to solve the problem]

The present invention provides a long first insulating sheet, a first conductor formed on one surface of the first insulating sheet extending in the longitudinal direction, and an end portion of each of the first insulating sheets attached to the first conductor. two first terminals exposed in the width direction of the insulating sheet;
a second insulating sheet laminated on the insulating sheet, a second conductor formed on one surface of the second insulating sheet extending in the longitudinal direction, and attached to the second conductor, each end of which is The second insulating sheet has two second terminals exposed in the width direction, the first and second insulating sheets are wound together with the first and second conductors, and the first and second terminals are wound together with the first and second conductors. This is a noise filter exposed from the end face of the wound body.

(Function) Since the second insulating sheet is laminated on the first insulating sheet, the second insulating sheet connects the first conductor formed on the first insulating sheet and the second insulating sheet 1. ~ and the second conductor formed above.Therefore, a capacitance is formed between the first and second conductors, that is, between the first and second terminals. The conductor itself forms an inductance between the first terminal and the second terminal.Thus, for example, one side of the first and second terminals is an input terminal and the other side is an output terminal. A line filter is constructed by Goshu.

〔Effect of the invention〕

According to this invention, a noise filter can be obtained simply by winding the first and second insulating sheets together with their respective conductors, so there is no need to assemble a plurality of discrete capacitors, inductors, etc. as in the past. Productivity is high and costs can be reduced.

Furthermore, by changing the attachment locations of the first and second terminals, it is possible to make modifications such as changing only the inductance value, and it is possible to obtain a noise filter with high performance insertion loss characteristics.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

(Example) Referring to FIG. 1, first, a long film sheet 12 and 1 made of an insulating material such as a polyester film
Prepare 4. These film sheets 12 and 14
Conductive foils 16 and 18 made of a highly conductive metal such as aluminum or copper are respectively pasted on the upper surface of the conductor foils 16 and 18 so as to extend continuously in the longitudinal direction.

First terminals 22a, 22b and second terminals 24a, 24b are attached to both ends of the conductor foils 16 and I8, respectively, by fixing another conductor foil 20 by spot welding or the like. That is, these terminals 22a to 24b are sandwiched between portions of the substantially rectangular conductor foil 20 whose ends are folded back and spot welded, and are therefore integrally fixed to the conductor foil 20. Therefore, the conductor foil 20 is spot welded to -ζ
- If the conductive foils 16 and 18 are fixed integrally with each other, the first terminals 22a, 22b and the second terminal 24a
, 24b are fixed to the conductive foil 16 and the conductor foil 16, respectively, and are electrically connected securely. In FIG. 1, the portions on the conductor foil 2o where spot welding is performed are marked with black circles. And each terminal 22a to 24
It is desirable that the portion b to be spot welded be formed into a flat shape.

When the four terminals 22a to 24b have been attached as shown in FIG. 1, after overlapping the film sheets 12 and 14, as shown in FIG. conductor foils 16 and 18
At the same time, the film sheets 12 and 14 are wound into a cylindrical shape.

A rolled or cylindrical body 28 formed as shown in FIG.
As shown in FIG. 3, E-shaped cores 30 and 32 are fitted from both sides of the hole 26. Cores 30 and 32 are made of a material with high magnetic permeability, such as ferrite, and constitute a magnetic circuit for conductor foils 16 and 18.

Next, the through capacitors 34 and 36 are respectively fitted into the first terminal 22a and the second terminal 24b of the terminals protruding from one end surface of the cylindrical body 28, as shown by dotted lines in FIG.

The inner electrodes of these feedthrough capacitors 34 and 36 are connected to the first terminal 22a and the second terminal 24b, respectively, and the outer surface electrodes are connected to cases 38 and 40 that cover the feedthrough capacitors 34 and 36, respectively. Terminals 38a and 40a are drawn out from 38 and 40. Note that these terminals 38a and 4
The terminal 0a is normally used as a grounding terminal, and it is desirable to provide a plurality of terminals in the cases 38 and 40. After fitting cores 30 and 32 and feedthrough capacitors 34 and 36, cylinder 28 is assembled onto printed circuit board 42, as shown in FIG. At this time, the above-mentioned terminal 22a
24b passes through the printed circuit board 42, and terminals 38a and 40a of the cases 38 and 40 are connected to a ground portion (not shown) of the printed circuit board 42. It is desirable that this ground portion be formed with as wide an area as possible.

Thereafter, the case 44 is placed over the printed circuit board 42. At this time, the ground portion of the printed circuit board 42 is connected to the case 44 at a plurality of locations, and a plurality of ground terminals 46 are led out from the case 44.

Note that the printed circuit board 42 may not be used and may be molded into the case 44 as it is. Further, the case 44 is usually a metal case so as to provide magnetic shielding, but it may also be a metal-plated plastic case.

An equivalent circuit of the 1° noise filter obtained as described above is shown in FIG. That is, the film sheet 12
Terminal 2 is connected by upper conductor foil 16 and cores 30 and 32.
There is an inductance L between terminals 2a and 22b, and an inductance L between terminals 24a and 24b due to conductor foil 18 on film sheet 14 and cores 30 and 32.
2 are formed respectively. Further, there is a distributed capacitance C between the conductor foils 16 and 18 sandwiching the film sheet 14.
I is formed. Note that feedthrough capacitors 34 and 36
constitutes capacitance C2 in FIG.

Length and width of conductor foils 16 and 18 and core 30
The values of inductances L1 and L2 are determined by the size and magnetic permeability of 32 and 32. And conductor foil 1
Opposing areas of 6 and 18 and film sheets 12 and 1
The value of capacitance C8 is determined by the size and dielectric constant of C4.

Normal mode noise can be removed by capacitance C1, and common mode noise can be removed by capacitance C2.

FIGS. 6 to 8 are illustrative views showing other embodiments of the present invention. In the previous embodiment, capacitance C2 was constituted by feedthrough capacitors 34 and 36. However, this feedthrough capacitor 34 and 36 within the cylinder 28
It is also possible to integrally form a capacitance C2 having a similar function. To that end, in this example:
A film sheet 48 is laminated between film sheets 12 and 14 as shown in FIG. 6=8-.

Conductive foils 50a and 50b are attached to one side of the film sheet 48 at both ends in the longitudinal direction, respectively.

Third terminals 52a and 52b are integrally fixed to these conductor foils 50a and 50b, respectively, by conductor foil 2o.

The film sheet 48 is then placed between the film sheets 12 and 14 and wound as a cylinder 28 as shown in FIG. 7, as in the previous embodiment.

Thereafter, as shown in FIG. 8, the core 3 is
0 and 32 are fitted. Then, the cylindrical body 28
Terminals 22a to 24b and terminals 5 and 2a are provided on one end surface of
and 52b protrude.

The third terminals 52a and 52b are used as ground terminals. Then, if necessary, it is placed in a case as shown in FIG. An equivalent circuit diagram of the noise filter completed in this way is shown in FIG.

The capacitance C2' in FIG. 9 is the conductor foil 50a.
and conductor foils 16 and 18, and between conductor foil 50b and conductor foils 16 and 18.

In this example, as shown in FIG. 9, the capacitance 02' is formed on both the input side and the output side, but the capacitance C2' is formed only on either the input side or the output side. may be formed. In that case, the conductive foil 50a or 50b may be formed only in the portion where the capacitance C2' needs to be formed.

10 and 11 show the first terminal 22a and the second terminal 24 of the embodiment shown in FIGS. 1 and 2.
Fig. 3 shows another embodiment of the present invention in which the conductor foils 16 and 18 are mounted slightly inward from their longitudinal ends.

In the embodiment shown in FIGS. 1O and 11, the first
between the terminals 22a and 22b and the second terminal 24
The distances between a and 24b are both shorter than those in the embodiment shown in FIGS. 1 and 2. Therefore, the first
The values of inductance and L2 shown in the equivalent circuit of FIG. 2 are smaller than those in the equivalent circuit of FIG.

On the other hand, the value of capacitance C5 is independent of the distance between the first terminals 22a and 22b and the second terminals 24a and 24b, and depends on the opposing areas of the conductor foils 16 and 18, etc. Therefore, according to this embodiment, only the inductance L and/or I52 can be changed without changing the value of the capacitance C3.

Therefore, the positions of the first terminals 22a and 22b and/or the second terminals 24a and 24b (in the longitudinal direction of the conductor 16 and/or 18) are set appropriately, and the opposing area of both the door bodies 16 and 18 is Optimal filter characteristics can be easily obtained by changing the area of the capacitance C2 and arbitrarily setting the value of the capacitance C2.

In addition, in the equivalent circuit diagram of Fig. 12, Fig. 12 (A)
shows the case where only the capacitance C3 is changed without changing the inductance L and I7□, and the 12th
Figure (B) shows a case where only the inductances L and L2 are changed without changing the capacitance C1.

13 and 14, the film sheet 48 of the embodiment shown in FIGS. 6 and 7 is divided into two film sheets 48a and 48b, and the first terminal 22
Fig. 3 shows another embodiment of the present invention in which the terminals 24a and 24a are mounted on the conductive foils 16 and 18 slightly inside their longitudinal ends.

Also in this embodiment, the first terminals 22a and 22b
and/or the inductance L, as in the embodiment shown in FIGS. 10 and 11, depending on the distance between the second terminals 24a and 24b.

And/or the value of L2 can be set arbitrarily. At the same time, in this example, the film sheet)
Since 48a and 48b are divided, the value of capacitance C2' in the equivalent circuit of FIG. 15 can be arbitrarily adjusted by appropriately setting their positions, that is, the positions of conductor foils 50a and 50b.

Note that such divided film sheets 48a and 48
b can also be applied to the embodiments shown in FIGS. 6 and 7 above.

Although not shown, the first terminal 22b and the second terminal 22b
Regarding the terminals 24b, the conductor foils 16 and 1
Of course, the attachment may be done at a different location, such as on the inside of the longitudinal end of the tube 8.

Note that the core, which is an iron core for inductance, does not have to be of the E type shown in the above embodiment, but may be of an I type or a U type, for example.

Furthermore, in the embodiments described above, conductor foils 16 and 1B or 50a and 50b are used as film sheets 12 and 1B.
4 or 48, these may be formed on the film sheets 12 and 14 or 48 by vapor deposition or plating.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a film sheet according to an embodiment of the present invention. FIG. 2 is an illustrative view showing a state in which the film sheets shown in FIG. 1 are overlapped and rolled up. 3(A) and 3(B) are a front view and a bottom view showing a state in which an E-shaped core is fitted into the cylindrical body formed as shown in FIG. 2. FIGS. 4(A) and 4(B) are a front view and a bottom view showing a noise filter completed through the steps shown in FIGS. 1 to 3. FIG. 5 is an equivalent circuit diagram of the embodiment shown in FIG. FIGS. 6 to 8 are illustrative views showing other embodiments of the present invention. FIG. 9 is an equivalent circuit diagram of a noise filter completed according to FIGS. 6 to 8. FIGS. 10 and 11 are illustrative views showing still other embodiments of the present invention. 12(A) and 12(B) are equivalent circuit diagrams of a noise filter completed according to the embodiment shown in FIGS. 10 and 11. FIG. FIGS. 13 and 14 are illustrative views showing other embodiments of the present invention. FIG. 15 is an equivalent circuit diagram of a noise filter completed according to the embodiment shown in FIGS. 13 and 14. FIG. 16 is a circuit diagram of a conventional noise filter formed by discrete components. In the figure, 12, 14, 48, 48a, 48b are film sheets, 16.1B, 20.50a and 50b are conductor foils, 22a and 22b are first terminals, 24a and 24b are second terminals, 30 and 32 is the core, 34.
36 is a feedthrough capacitor, and 52a and 52b are third terminals. Patent applicant Murata Manufacturing Co., Ltd. Agent Patent attorney Yama 1) Yoshihito 1) LrJ Trouble 1ψ He Hehe■ Taste -

Claims (1)

[Scope of Claims] A long first insulating sheet; a first conductor formed on one surface of the first insulating sheet and extending in the longitudinal direction; attached to the first conductor, each end of which is attached to the first conductor; two first terminals whose portions are exposed in the width direction of the first insulating sheet; a second insulating sheet laminated on the first insulating sheet; and two second terminals attached to the second conductor, each end of which is exposed in the width direction of the second insulating sheet, and a second insulating sheet is connected to the first and second insulating sheets.
A noise filter that is wound together with a conductor, the first and second terminals being exposed from an end surface of the wound body.