JPH02276305A - Noise filter - Google Patents

Abstract

PURPOSE:To dispense with the assembling of a noise filter with plural discrete capacitors or inductances, to improve productivity, and to realize cost reduction by comprising the noise filter by winding first and second insulating sheets with respective conductor. CONSTITUTION:Conductive foil 16 and 18 are stuck on the upper plane of the insulating sheets 12 and 14 extending successively in its longitudinal direction. Another conductive foil 20 are set as terminals 22 and 24 by fixing at both ends of the conductive foil 16. The conductive foil 20 is fixed slmilarly in the center part of the conductive foil 18, which is set as a terminal 26. Next, after the sheet 12 being superimposed on the sheet 14, they are wound across a bobbin 28 with the conductive foil 16 and 18 by setting the upper plane of the sheet 12 inside, and a winding body 30 of doughnut type setting the bobbin 28 as a core is completed. Two formed winding bodies 30 are formed in such a way that whose end faces to which the terminals 22-26 are not protruded are superimposed, and cores 38 are inserted from both sides to the part of a through hole 32, then, the noise filter is completed.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a noise filter, in which an inductor is connected between input and output terminals like a line filter, and a capacitor is 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 diagrams of FIGS. 14 and 15.

[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.

[Means for solving problems]

This invention provides a long first insulating sheet, a first
a first conductor formed extending in the longitudinal direction on one main surface of the insulating sheet; two terminals attached to the first conductor, each end of which is exposed in the width direction of the first insulating sheet; a second insulating sheet laminated on the first insulating sheet; and a second conductor formed on one main surface of the second insulating sheet to extend in the longitudinal direction; a sheet is wound with the first and second conductors;
A noise filter comprising at least two winding bodies whose terminals are not exposed from the end faces thereof, and connecting means for connecting second conductors of the winding bodies.

[Function] Since the wound body is formed by winding a laminated second insulating sheet on the first insulating sheet, the second insulating sheet is formed on the first insulating sheet. The first conductor is sandwiched between the first conductor formed on the second insulating sheet and the second conductor formed on the second insulating sheet. Therefore, a capacitance is formed between the first and second conductors. Also, an inductance is formed between the two terminals by the first conductor itself. Then, for example, second conductors of the two wound bodies are connected to each other by a connecting means such as a lead wire. Therefore, the capacitances of the two windings are connected in series. Therefore, for example, a line filter is configured by setting one terminal of each of the two wound bodies as an input side terminal and the other as an output side terminal.

〔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.

In addition, since this noise filter is formed by at least two wound bodies, the arrangement of the wound bodies may be devised.
Mutual inductance, that is, the coupling coefficient of a plurality of self-inductances can be arbitrarily set by arranging a core in a wound body.

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. 3, first, long film sheets 12 and 1 made of an insulating material such as a polyester film are
Prepare 4゛, these film sheets) 12 and 1
Conductor foils 16 and 18 made of a highly conductive metal such as aluminum or copper are attached to the upper surface of the electrode 4 so as to extend continuously in the longitudinal direction thereof, respectively.

By fixing separate conductor foils 20 to both ends of the conductor foil 16, for example, by spot welding,
Terminals 22 and 24 are attached. A terminal 26 is attached to the center of the conductive foil 18 by spot welding the conductive foil 20 in the same manner. In addition, in FIG. 3, the portions on the conductor foil 20 where spot welding has been performed are marked with black circles.

After completing the attachment of the three terminals 22 to 26 as shown in FIG. 3, after overlapping the film sheets 12 and 14,
The film sheets 12 and 14 are wound around the bobbin 28 along with the respective conductor foils 16 and 18, as shown in FIG. 2, with the upper surface side of the film sheet 12 facing inside. Then, a doughnut-shaped wound body 30 having the bobbin 28 as a winding core is completed. Three terminals 22 to 26 protrude from the right end surface of the wound body 30. Note that the cylindrical bobbin 28 is formed from an insulating material in order to keep the conductor foil 16 insulated. Then, the through hole 3 of the bobbin 28
2, a core 38 is fitted therein as will be described later.

As shown in FIG. 1, the two wound bodies 30 formed as shown in FIG. 2 are overlapped at their end surfaces from which the terminals 22 to 26 do not protrude. Thereafter, semicircular insulating plates 34 are attached to the surfaces from which the terminals 22 to 26 protrude, respectively, so that the terminals 22 to 26 are inserted therethrough. All the terminals 22-26 are then bent vertically at the point where they exit the insulating plate 34, as shown in FIG. Further, the terminals 26 are each bent by 90" at the lower end of the insulating plate 34. Therefore, the terminals 26 of the two 3° windings have their tips overlapped, as shown in FIG. 1(B). In this way, the ends are cut to a length that makes contact with each other, and solder 36 is applied to the tips thereof.In this way, the terminals 26 of the two windings 30 are electrically connected by the solder 36. Although not shown, the terminal 26 is connected to the terminal 2.
2. This task will be easier if you take it out on the opposite side from 24.

The two integrated winding bodies 30 have through holes 3 from both sides.
The core 3B is fitted into each of the portions 2 and 2. Then, the noise filter 10 is completed. U-shaped core 3
8 is made of a material with high magnetic permeability, such as ferrite, and constitutes a magnetic circuit of the noise filter IO.

The equivalent circuit of the noise filter 1o obtained in this way is shown in FIG.
A self-inductance L is formed between the terminals 22 and 24 by the two cores 38, respectively. Further, distributed constant type capacitances C are formed between conductive foils 16 and 18 which sandwich the film sheet 12, respectively. And since both terminals 26 are commonly connected by solder 36, the two capacitances C are connected in series, and the mutual inductance M between the two self-inductances depends on the relative position of the two windings 30. It is determined. Therefore, when reducing the degree of coupling between two self-inductances to reduce the value of mutual inductance M, it is sufficient to place the wound bodies 30 apart from each other. Therefore, in this noise filter 10, the mutual inductance M There is a large degree of freedom in values.

5 to 7 are illustrative views showing other embodiments of the present invention. In the previous embodiment, a distributed constant type capacitance C was formed in the noise filter 10, but in this embodiment, in addition to the capacitance C, a lumped constant type capacitance C was formed in the wound body 28. ' is integrally formed. For that purpose, in this embodiment, as shown in FIG. 7, the length of the conductor foil 18 is shortened, and
8, the insulation from the conductor foil 18 is maintained, and the conductor foil 4
0 and 42 are pasted on the film sheet 14, respectively. Terminals 44 and 46 are also attached to the conductive foils 40 and 42 by the conductive foil 20, respectively. Therefore, when wound around the bobbin 28, five terminals 22 to 26, 44 and 46 protrude from the right end surface of the wound body 30', as shown in FIG. Terminals 44 and 46 are connected to terminal 2 as shown in FIG.
2 and 24, it is bent vertically at the point where it exits the insulating plate 34.

An equivalent circuit of this noise filter 10' is shown in FIG. That is, the conductor foils 40 and 42 and a portion of the conductor foil 16 each create a lumped constant capacitance C′.
is formed. Therefore, the noise filter 10' is
Since it is formed by two windings 30'', there are also four capacitances C in the noise filter 10'.
' is formed.

In the embodiments shown in FIGS. 5 to 7, the capacitance C' was formed on both the input side and the output side, as shown in FIG. It may be formed only on either one of the output sides.
In that case, the conductive foil 40 or 42 may be formed on the side where the capacitance C' is formed.

Furthermore, FIG. 9 shows a modification of the noise filter lO of the embodiment shown in FIG. be. That is, in this modification, the conductor foil 18 is attached near one end of the film sheet 14, and the terminal 26 is attached to the center of the conductor foil 18.

Then, by constructing two wound bodies 30 in the same manner as in the embodiment of FIG. 3 and arranging them as shown in FIG. 1, a noise filter 10 having an equivalent circuit as shown in FIG. 10 can be obtained. It will be done. In this modification, the capacitance C is formed closer to the terminal 22, and its value can be arbitrarily adjusted depending on the size of the conductor foil 18. By appropriately setting the coupling between the inductances L formed in the two wound bodies 30, the residual inductance of the capacitance C can be minimized.

In addition, FIG. 11 shows the noise filter 10 of the embodiment in FIG.
In this modification example, as well as the modification example shown in FIG. 9, a relatively small area of conductor foil 18 is attached to the upper surface of the film sheet 14 so as to be unevenly distributed on the terminal 22 side. By constructing two wound bodies 30' and arranging them as shown in FIG. 5, a noise filter 10' having an equivalent circuit as shown in FIG. 12 can be obtained. Also in this modification, the capacitance C' is formed closer to the terminal 22, and its residual inductance is reduced.

These modifications shown in FIGS. 9 and 11 can be applied when the value of capacitance C or C' may be smaller than the value of inductance L. Furthermore, by forming the capacitance C close to the terminal 22 and adjusting the coupling, the residual inductance of the capacitance C or C' can be reduced. As a result, the insertion loss can be improved as shown by the dotted line B in FIG. Incidentally, solid line A indicates the case of the embodiment in FIG. 3 or FIG. 7.

Note that the noise filter 10 (10') described above is formed of two wound bodies 30 (30') having the same characteristics.
By varying the length and width of the conductor foils 16 and 18 in the winding 30 (30''), the self-inductance and capacitance C can also be varied.

Furthermore, the core for the inductance does not have to be U-shaped as shown in the above embodiments, but may be of E, I type or E, E type, for example.

In the above-described embodiments, the conductor foils 16 and 18 or 40 and 42 were attached to the film sheets 12 and 14, but these can also be formed on the film sheets 12 and 14 by vapor deposition or plating.

[Brief explanation of drawings]

FIG. 1(A) and FIG. 1(B) are a right side view and a front view showing an embodiment of the present invention. 2(A) and 2(B) are a side view and a sectional view showing the wound body used in the embodiment of FIG. 1. FIG. 3 is a perspective view showing the film sheet used in this example. FIG. 4 is an equivalent circuit diagram of the embodiment shown in FIG. 5 to 7 are illustrative views showing other embodiments of the present invention. FIG. 8 is an equivalent circuit diagram of the embodiment shown in FIGS. 5 to 7. FIG. 9 is an illustrative view showing a modification of the embodiment shown in FIG. 3. FIG. 10 is an equivalent circuit diagram of the embodiment shown in FIG. FIG. 11 is an illustrative view showing a modification of the embodiment shown in FIG. FIG. 12 is an equivalent circuit diagram of the embodiment shown in FIG. 11, and FIG. 13 is a graph showing a comparison of the insertion loss characteristics of the respective embodiments. FIGS. 14 and 15 are circuit diagrams of conventional noise filters formed by discrete components. In the figure, 10 and 10' are noise filters, 12
and 14 are film sheets, 16, 18.40 and 42 are conductor foils, 22 to 26.44 and 46 are terminals, 3
6 indicates solder, and 38 indicates a core. Patent Applicant Murata Manufacturing Co., Ltd. Agent Patent Attorney Yama 1) Yoshihito Figure (A) Figure 2 (A) Figure (A) (B) (B) Figure Figure Figure Figure 10' Figure Figure 10 Figure L Figure 11 Figure 12

Claims (1)

[Scope of Claims] 1. Each includes a long first insulating sheet, a first conductor formed on one main surface of the first insulating sheet extending in the longitudinal direction, and attached to the first conductor. two terminals, each end of which is exposed in the width direction of the first insulating sheet, a second insulating sheet laminated on the first insulating sheet, and one main terminal of the second insulating sheet. a second conductor formed on a surface extending in the longitudinal direction thereof, the first and second insulating sheets are wound together with the first and second conductors, and the terminal is exposed from the end surface thereof; A noise filter comprising at least two winding bodies and connecting means for connecting the second conductors of the winding bodies. 2. The noise filter according to claim 1, wherein the wound body is formed into a cylindrical shape, and a core made of a ferromagnetic material is inserted into a hollow portion of the wound body. 3. The noise filter according to claim 1, wherein the second conductor is formed in an arbitrary size on one main surface of the second insulating sheet.