JPH06177692A - Distribution constant type lc filter - Google Patents

Abstract

PURPOSE:To improve attenuation characteristics in low frequencies by reducing leaking magnetic flux and thereby enlarging inductance. CONSTITUTION:The surface of a cylindrical body 28 made by winding conductive foil and a dielectric is entirely covered with a core 30 and the core 32 and a closed magnetic circuit is constituted. Terminals 22a, 24a and 52a from the cylindrical body 28 are taken out to an outside from holes 34 for taking out the terminals provided on the core 32. By using a sealed type in such a manner, the leaking magnetic flux is reduced and the inductance can be enlarged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to composite parts such as capacitors and coils.

[0002]

2. Description of the Related Art FIG. 14, FIG. 15, FIG. 16, FIG.
Reference numeral 8 is a conventional noise filter described in, for example, Japanese Patent Publication No. 1-316013. Figure 14 shows the film
FIG. 15 is a perspective view showing a state in which the film sheets are overlapped and rolled up, FIG. 16 (a) and FIG.
17B is a front view and a bottom view showing a state where the E-shaped core is fitted in the cylindrical body formed as shown in FIG. 15, FIG. 17 is an equivalent circuit, and FIG. 18 is a perspective view showing a leakage magnetic flux. Figure 1
4, 1 in FIGS. 15, 16, 17, and 18
2, 14, 48 are film sheets, 16, 18, 20,
50a and 50b are conductive foils, 22a and 22b are first terminals, 24a and 24b are second terminals, 52a and 52b are third terminals, 26 is a hole, 28 is a cylindrical body, 30 and 32 are cores, 40 Is a leakage magnetic flux, 42 is a magnetic flux generated in the cores 30, 32, C1, C2, C3 are capacitances, L1, L
2 is an inductance.

In FIG. 14, a conductive foil 16 is placed on the film sheet 12, and one terminal 22 is placed on the conductive foil 16.
a and the other terminal 22b are fixed by the conductive foil 20 to form a first electrode. Conductive foils 50a and 50b are superposed on the film sheet 48, one terminal 52a is fixed on the conductive foil 50a, and the other terminal 52b is fixed on the conductive foil 50b by the conductive foil 20 to form a second electrode. To do. A conductive foil 18 is placed on the film sheet 14, and one terminal 24a and the other terminal 24b are fixed on the conductive foil 18 by a conductive foil 20 to form a third electrode. Next, the second electrode is overlaid on the first electrode, and the third electrode is overlaid thereon. Figure 15
In, the conductive foils respectively connected to the first electrode, the second electrode, and the third electrode are stacked and wound around the hole 26 to form a cylindrical body 28. In FIG. 16, the E-shaped cores 30 and 32 are fitted in the cylindrical body 28 to form an LC filter. FIG. 17 shows an equalizing circuit, and L1 is an inductance formed by the conductive foil 16. Similarly, L2 is conductive foil 1
It is an inductance formed by 8. C1 is a capacitor composed of the conductive foils 16 and 18 and the film sheet 48. Similarly, C2 is conductive foil 16, 50
a and film sheet 48, conductive foils 18 and 50a and film sheet 14, conductive foils 16 and 50b and film sheet 4
8 and the conductive foils 18, 50b and the film sheet 14 are capacitors. C3 is one terminal 22
It is a stray capacitance generated between a and 24a and the other terminals 22b and 24b. In FIG. 18, 42 is a magnetic flux generated in the cores 30 and 32 by the current flowing through the cylindrical body 28, and 40 is a leakage magnetic flux that cannot be contained in the cores 30 and 32.

[0004]

Since the conventional device uses the E-type core as described above, there is a leakage magnetic flux, and a sufficient inductance cannot be secured, so that a low frequency (150 k to 3 MH) is obtained.
The amount of attenuation in z) is not sufficient. Therefore, although it is an LC composite part, additional parts must be added.
Also, the strength is weak because the terminals are only fixed with conductive foil. Further, the high frequency characteristics are deteriorated due to the coupling between the terminals on the primary side and the secondary side.

The present invention has been made to solve the above problems, and is to improve the characteristics of the filter at low frequencies by reducing the leakage magnetic flux and securing a sufficient inductance. (EN) Provided is a distributed constant type LC filter which can be dealt with by one component without using other components. Further, the mechanical strength of the terminal is increased and the coupling between the primary side and the secondary side is reduced to improve the high frequency characteristics of the filter.

[0006]

DISCLOSURE OF THE INVENTION A distributed constant type LC filter according to the present invention covers, for example, a cylindrical body formed by winding a conductive foil and a dielectric as a core to form a closed magnetic circuit. It is a closed type distributed constant type LC filter.

The distributed constant type LC filter according to the present invention is provided with a substrate for taking out terminals.

Further, the primary side terminal and the secondary side terminal are electrically separated by a ground, or the primary side terminal and the secondary side terminal are respectively taken out from different surfaces of the core and spatially separated. .

[0009]

According to the present invention, since the leakage flux is reduced by using the above-mentioned structure, a larger inductance can be secured and the attenuation characteristic at low frequency can be improved. With this improvement, it is possible to take measures with only one distributed constant type LC filter without using other components, so that the mounting area of the components can be reduced and the number of man-hours for mounting the components can be reduced.

Further, by strengthening the mechanical strength of the terminal by using the substrate, it is possible to prevent breakage and defective contact of the terminal during manufacture, transportation and use.

Further, the high frequency characteristics of the filter can be improved by reducing the coupling between the primary side terminal and the secondary side terminal.

[0012]

EXAMPLES Example 1. FIG. 1 is a sectional view of a distributed constant type LC filter showing an embodiment of the present invention, and FIG. 2 is a bottom view.
1 is a sectional view taken along line XX in FIG. 2, and a portion shown in FIG. 1 is a sectional view taken along line YY in FIG. FIG. 3 shows an equivalent circuit, and FIG. 4 shows frequency characteristics of attenuation. In FIGS. 1, 2 and 3, 22a and 22b are first terminals, 24a and 24b are second terminals, 52a and 52b are third terminals, 26 is a core insertion hole, and 28 is a conductive plate or a conductive plate. A cylindrical body formed by alternately stacking foils and dielectrics and winding them, cores 30 and 32, holes for taking out terminals, C1 and C2 capacitances, and L1 and L2 inductances.

In FIGS. 1 and 2, the core 32 is made of, for example, nickel-zinc based high-permittivity, high-frequency ferrite, and is inserted into the hole 26 at the center of the cylindrical body 28 so as to cover the bottom and side surfaces of the cylindrical body. Attached to. The core 30 is attached in close contact with the core 32 so as to cover the opening of the core 32. First, second and third terminals 22a, 22b, 2
4a, 24b, 52a, and 52b are taken out from the holes 34 for taking out terminals formed in the bottom surface of the core 32, respectively.

Since the distributed constant type LC filter is constructed as described above, the entire surface of the cylindrical body 28 is covered with the cores 30 and 32 to form a closed magnetic circuit, and the leakage magnetic flux is reduced.
Therefore, in the equivalent circuit shown in FIG. 3, the common mode inductances L1 and L2 are increased, and the attenuation amount at a low frequency is lower than that of the conventional product like the frequency characteristic of the common mode attenuation amount of the filter shown in FIG. Can be increased. Due to this improvement, other parts are not used and distributed constant type L
Since it is possible to take measures with only one C filter, the mounting area of the component can be reduced and the number of man-hours for mounting the component can be reduced.

Example 2. FIG. 5 is a sectional view of a distributed constant type LC filter showing another embodiment of the present invention, FIG. 6 is an assembly plan view of a substrate for taking out terminals and a jig for fixing the substrate, and FIG. 7 is an assembly perspective view. 22a in FIGS. 5, 6 and 7.
22b is a first terminal, 23a and 23b are first external terminals, 24a and 24b are second terminals, 25a and 25b are second external terminals, 52a and 52b are third terminals, 53a,
53b is a third external terminal, 26 is a hole for inserting a core, 28
Is a cylindrical body formed by winding conductive foils and dielectrics alternately and winding them, 30, 32 are cores, 34 are holes for taking out terminals, 60 is a board for taking out terminals, and 62 is a jig for fixing the board. .

In FIGS. 5, 6, and 7, the first terminal 2
2a and 22b are connected to the first external terminals 23a and 23b attached to the terminal extraction board 60 by soldering or the like. Similarly, the second terminals 24a and 24b are connected to the second external terminals 25a and 25b, respectively, and the third terminals 52a and 52b are the third external terminals 53, respectively.
a, 53b. External terminals 23a, 23b, 2
5a, 25b, 53a and 53b are taken out from the terminal taking-out holes 34 formed in the bottom surface of the core 32. The board fixing jig 62 is designed so as to be closely inserted into the inside of the hole 26, and is attached to the terminal extracting board.
As described above, the terminal extraction substrate 60 and the first, second, and third external terminals 23a, 23b, 25a, 25b,
By providing 53a and 53b, the mechanical strength of the terminal can be increased, and damage during manufacture, transportation, and use and contact failure of the terminal can be prevented.

Embodiment 3. In the second embodiment, the external terminals 23a, 23b, 25 are formed on the terminal extracting substrate 60.
Although the case where a, 25b, 53a, and 53b are attached in advance is shown, these external terminals are not present in the terminal take-out substrate 60, and instead, the terminals 22a, 22b, and 24a that come out from the cylindrical body 28 are provided. , 24b, 52
It may have a passage hole for passing a and 52b. The through hole provided in the terminal extracting substrate 60 allows the terminal from the cylindrical body 28 to pass therethrough, and the body portion of the terminal is fixed by soldering or the like. Therefore, the mechanical strength of the terminal can be increased, and the same effect as that of the above-described embodiment can be obtained.

Example 4. In the second and third embodiments, the cores 30 and 32 are the same as those in the first embodiment.
Although the case where the entire surface of the cylindrical body 28 is covered by the above is shown, the case where a conventional E-shaped core is used as shown in FIG. That is, the cylindrical body 28
By providing the terminal lead-out substrate 60 between the E-shaped core and the E-shaped core, the same effects as those of the above-described second and third embodiments can be obtained.

Example 5. FIG. 8 is a plan view of a terminal extracting board showing another embodiment of the present invention, FIG. 9 is an equivalent circuit, and FIG.
0 indicates the frequency characteristic of the attenuation amount. 2 in FIGS. 8 and 9
3a and 23b are first external terminals, and 25a and 25b are second
External terminals, 53a and 53b are third external terminals, 60 is a terminal extracting substrate, 62 is a substrate fixing jig, 64 is a ground pattern, C1, C2 and C3 are capacitances,
L1 and L2 are inductances.

In this embodiment, the terminal lead-out board 60 is made of a printed board as shown in FIG. 8, and the first external terminals 23a, 23b and the second external terminals 25a, 25 are formed.
The portion other than b is the ground pattern 64. The ground pattern 64 is electrically connected to the third external terminals 53a and 53b. Like the second embodiment, the terminal lead-out board 60 includes a board fixing jig 62 and is attached as shown in FIG.

As described above, in the terminal lead-out board 60, the primary side external terminal 2 is formed by the ground pattern 64.
By electrically separating the external terminals 3a and 25a from the external terminals 23b and 25b on the secondary side, as shown in the equivalent circuit of FIG. 9, the capacitance C3 that acts as a stray capacitance in the conventional product and deteriorates the high frequency characteristic is a capacitance. Like C2, it works as a line-ground capacitor. With such a configuration, it is possible to provide a distributed constant type LC filter having better high frequency characteristics than the conventional product as shown in FIG.

Embodiment 6. In the fifth embodiment, as shown in the second embodiment, the cylindrical body 2 is formed by the cores 30 and 32.
Although the case where 8 is entirely covered is described as an example, the terminal extracting substrate 60 is provided in the noise filter using the E-shaped core as shown in FIG. The effect similar to that of the fifth embodiment can be obtained by adding the ground pattern 64 to the.

Example 7. FIG. 11 is a sectional view of a distributed constant type LC filter showing another embodiment of the present invention, and FIG. 12 shows an equivalent circuit. In FIG. 11, 22a and 22b are first terminals, 23a and 23b are first external terminals, and 24a and 24b.
Is a second terminal, 25a and 25b are second external terminals, 52
a and 52b are third terminals, 53a and 53b are third external terminals, 26 is a hole for inserting a core, 28 is a cylindrical body formed by winding conductive foil and dielectric alternately alternately, 30, 32
Is a core, 34 is a hole for taking out a terminal, 60 is a board for taking out a terminal, 62 is a board fixing jig, C1, C2 and C3 are capacitances, and L1 and L2 are inductances.

In FIG. 11, the first terminal 22a, the second terminal 24a, and the third terminal 52a are respectively attached to the terminal extracting substrate 60 as primary terminals.
Are connected to the external terminal 23a, the second external terminal 25a, and the third external terminal 53a by soldering or the like. Similarly, the other first terminal 22b, second terminal 24b and third terminal 22b
52b of the first external terminal 23b, the second external terminal 25b, and the third external terminal 53b, which are the secondary side terminals and are attached to the terminal extracting substrate 61 on the opposite side of the terminal extracting substrate 60, respectively. Connected to. External terminals 23a, 23b, 25a, 25b, 53a, 53b
Is a hole 34 for taking out terminals, which is formed in the cores 30, 32.
Taken out.

As described above, the terminal extracting substrates 60, 6
1 are separated and arranged on both sides of the cylindrical body 28, and the external terminals 23a and 25a on the primary side and the external terminals 23b and 25b on the secondary side are provided.
12 is spatially separated, it is possible to reduce the capacitance C3, which is a stray capacitance in the conventional product and deteriorates the high frequency characteristic as shown in the equivalent circuit of FIG. With such a configuration, as shown in FIG. 10, a distributed constant type LC having better high frequency characteristics than the conventional product.
A filter can be provided.

Example 8. The core 3 in the first embodiment.
The cross section of 0 has a U-shape, and the cross section of the core 32 has an E shape. As shown in FIG.
The 0 and the core 32 may have other shapes.
FIG. 13A shows a case where the cross section of the core 30a is I-shaped and the cross section of the core 32a is E-shaped. In the case of FIG. 13B, the cross section of the core 30b is T-shaped, and the cross section of the core 32b is U-shaped. In the case of FIG. 13C, the core 30
Both c and the core 32c show a case where the cross section is E-shaped. As long as the cylindrical body 28 is hermetically sealed by the core in this manner, the core may have any shape.
Further, as described above, not only the two cores may be hermetically sealed, but also three or more cores may be hermetically sealed. It is assumed that the portions where these cores are in contact are in close contact with each other by means of an adhesive or friction with each other, and are configured so as not to be easily separated.

Example 9. In the above-described first to eighth embodiments, the cylinder 28 is described on the assumption that the cylinder 28 shown in the conventional example is used, but the cylinder 28 needs to be the same as the cylinder described in the conventional example. However, it does not matter even if it is constituted by another structure. Further, in the above embodiment, the case where the core is a cylinder is shown, but the shape sealed inside the core does not have to be a cylinder, and may be another shape such as a cube or a rectangular parallelepiped. Alternatively, it may have a complicated shape. When the shape of the object to be sealed changes in this way, the internal shape of the core may be changed accordingly.

[0028]

As described above, according to the present invention, a sealed type is used as a core, which covers the surface of a cylindrical body formed by winding a conductive foil and a dielectric and forms a closed magnetic circuit. Therefore, the leakage magnetic flux can be reduced, a larger inductance can be secured, and the attenuation characteristic at low frequencies can be improved. With this improvement, it is possible to take measures with only one distributed constant type LC filter without using other components, so that the mounting area of the components can be reduced and the number of man-hours for mounting the components can be reduced.

Further, by using the substrate for taking out the terminal and the external terminal, the mechanical strength of the terminal can be strengthened, and the damage and the contact failure of the terminal at the time of manufacture, transportation and use can be prevented.

Further, by electrically or spatially separating the primary side terminal and the secondary side terminal from each other, it is possible to reduce the coupling between the primary side and the secondary side and improve the attenuation characteristic of the filter at high frequencies.

[Brief description of drawings]

FIG. 1 is a sectional view of a distributed constant type LC filter showing an embodiment of the present invention.

FIG. 2 is a bottom view of the distributed constant type LC filter showing the embodiment of the present invention.

FIG. 3 is an equivalent circuit diagram of a distributed constant type LC filter showing an embodiment of the present invention.

FIG. 4 is a frequency characteristic diagram of an attenuation amount of a distributed constant type LC filter showing an embodiment of the present invention.

FIG. 5 is a sectional view of a distributed constant type LC filter showing another embodiment of the present invention.

FIG. 6 is an assembly plan view of a terminal extracting board and a board fixing jig showing another embodiment of the present invention.

FIG. 7 is an assembled perspective view of a terminal extracting board and a board fixing jig showing another embodiment of the present invention.

FIG. 8 is a plan view of a terminal extracting board showing another embodiment of the present invention.

FIG. 9 is an equivalent circuit diagram of a distributed constant type LC filter showing another embodiment of the present invention.

FIG. 10 is a frequency characteristic diagram of the attenuation amount of a distributed constant type LC filter showing another embodiment of the present invention.

FIG. 11 is a sectional view of a distributed constant type LC filter showing another embodiment of the present invention.

FIG. 12 is an equivalent circuit diagram of a distributed constant type LC filter showing another embodiment of the present invention.

FIG. 13 is a diagram showing another embodiment of the present invention.

FIG. 14 is a development view of a film sheet of a conventional distributed constant type LC filter.

FIG. 15 is a perspective view showing a state in which film sheets of a conventional distributed constant type LC filter are overlapped and rolled up.

FIG. 16 shows a conventional distributed constant type LC filter having a cylindrical body with E
The front view and bottom view showing the state where the mold core is fitted.

FIG. 17 is an equivalent circuit diagram of a conventional distributed constant type LC filter.

FIG. 18 is a perspective view showing a leakage magnetic flux of a conventional distributed constant type LC filter.

[Explanation of symbols]

 12, 14, 48 Film sheet 16, 18, 20, 50a, 50b Conductive foil 22a, 22b First terminal 23a, 23b First external terminal 24a, 24b Second terminal 25a, 25b Second external terminal 26 hole 28 Cylindrical body 30, 32 Core 34 Hole for taking out terminal 40 Leakage magnetic flux 42 Magnetic flux generated in core 52a, 52b Third terminal 53a, 53b Third external terminal 60, 61 Terminal taking-out substrate 62 Board fixing jig Tool 64 Ground pattern C1, C2, C3 Capacitance L1, L2 Inductance

Claims (4)

[Claims] 1. A distributed constant type LC filter comprising a dielectric between a plurality of conductors, wherein terminals are taken out from each conductor, and the conductor and the dielectric are enclosed to form a closed magnetic circuit. A distributed constant type LC filter, characterized in that it has a type core. 2. A distributed constant LC filter having a dielectric between a plurality of conductors, wherein terminals are taken out from each conductor, and a core covering at least a part of the surfaces of the conductor and the dielectric is provided. A distributed constant type LC filter having a substrate for taking out terminals inside. 3. In the distributed constant type LC filter,
The terminal has a terminal on the primary side and a terminal on the secondary side, the board for taking out the terminal is made of a printed board, and a ground formed between the terminal on the primary side and the terminal on the secondary side on the board. The distributed constant type LC filter according to claim 2, wherein the LC filters are separated by a pattern. 4. The above distributed constant type LC filter,
The terminal has a terminal on the primary side and a terminal on the secondary side, and the terminal on the primary side and the terminal on the secondary side are taken out in different directions. The distributed constant type LC filter described.