JPH0974047A - Chip-type lc filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a chip-type LC filter by constituting an inductance element for constituting one portion of the chip-type LC filter using a nonlinear conductor and coating it with a resin including a magnetic powder. SOLUTION: A chip-type LC filter consists of a cylindrical central conductor 8, a cylindrical capacitor 4 which becomes one capacitor element being fit to a junction part 9 located at the center in axial direction of the central conductor 8 and being electrically connected, and nonlinear-shaped conductors 2 and 3 which become two inductance elements being formed at both edges excluding the central part in the axial direction of the central conductor 8 at both edges of the cylindrical capacitor 4. Then, the chip-type LC filter 1 consists of a resin 12 including a magnetic powder for covering the nonlinear-shaped conductors 2 and 3 and metal caps 10 and 11 which become external terminals which are electrically connected to each one edge part of the nonlinear conductors 2 and 3 and cover the resin 12, thus obtaining the compact chip-type LC filter 1 whose attenuation characteristics do not deteriorate and which do not easily resonate with other components even if the inductance elements become small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type LC filter, and more particularly to a chip type LC filter used as a noise filter and constituting a T type filter circuit.

[0002]

2. Description of the Related Art FIG. 4 is a partial longitudinal sectional view showing a part of a conventional chip type LC filter. FIG. 5 is a perspective view of a central conductor which constitutes a part of a conventional chip type LC filter. The chip-type LC filter 20 constitutes a so-called T-type filter circuit including two inductance elements and one capacitor element. More specifically, the two inductance elements are cylindrical ferrite beads 30 and 40 having through holes, and one capacitor element is a pair of electrodes 60 on the inner and outer peripheral surfaces of the dielectric 80. , 70 with a through-hole cylindrical capacitor 50. In this chip type LC filter 20, the ferrite beads 30 and 40 are arranged on both ends of the cylindrical capacitor 50, and the element 3
The cylindrical central conductor 90 shown in FIG. 5 is inserted into the through holes 0, 50 and 40. This center conductor 90 is
A joint portion 100 that projects outward is provided at the center in the axial direction, and the joint portion 100 is electrically connected to the electrode 60 on the inner peripheral surface of the cylindrical capacitor 50, and each of the ferrite beads 30 and 40. One end is a metal cap 1 which is electrically connected to both ends of the center conductor 90 and serves as an external terminal.
10, 120 covered.

[0003]

By the way, in the conventional chip type LC filter 20 having such a structure, two ferrite beads 30, 40 and one cylindrical capacitor 50 of the central conductor 90 are provided. Since they are aligned in the axial direction, the axial direction becomes longer. That is, the outer dimension in the length direction becomes large, and the mounting density cannot be increased. In particular, the ratio of the ferrite beads 30 and 40 to the external dimensions of the chip-type LC filter is as large as about 70%, and in order to downsize the chip-type LC filter, the ferrite beads 30 and 40 are further downsized. Is desired.

However, the ferrite beads 30, 4
If 0 is simply downsized, the inductance component becomes smaller and the resistance component becomes smaller. For this reason, the amount of attenuation of the chip type LC filter 20 becomes small, and it becomes difficult to remove noise, and the chip type LC filter 20 easily resonates with other parts.

The present invention relates to a conventional chip type LC filter 2
In order to solve the above problem in No. 0, even if the inductance element becomes small, the attenuation characteristic does not deteriorate, and it is difficult to cause resonance with other parts,
An object is to provide a small chip type LC filter.

[0006]

According to the present invention, there is provided a cylindrical central conductor, and a pair of external conductors that are externally fitted to the central portion of the central conductor in the axial direction and electrically connect one electrode thereof to the central conductor. A capacitor element having an electrode of, and an inductance element in which a non-linear conductor electrically connected to the central portion is formed on each of both ends of the central conductor except the central portion, and the inductance element. A chip-type LC filter comprising a resin containing magnetic powder for coating and an external terminal electrically connected to an end of the inductance element. The center conductor is a chip-type LC filter formed by forming a metal plate, which has zigzag shape on both ends excluding the center of the rectangle, in the width direction and forms a cylindrical shape.

According to the present invention, since the inductance element forming a part of the chip type LC filter 20 is made of a non-linear conductor, the magnetic path becomes long, the inductance component becomes large, and the resistance component becomes large. Grows larger. Further, since the inductance element is covered with the resin containing the magnetic powder, the inductance component becomes larger. Therefore, the length of the inductance element can be shortened to reduce the size. Further, the tubular center conductor forming a part of the chip type LC filter can be formed by rolling in the width direction a metal plate having zigzag shape on both ends except for the central portion of the rectangle.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial longitudinal sectional view showing a part of one embodiment of the chip type LC filter of the present invention. FIG. 2 is a plan view of a metal plate used as a central conductor which constitutes a part of the chip type LC filter of the present invention. FIG.
It is a perspective view of a central conductor which constitutes a part of chip type LC filter of the present invention. This chip type LC filter 1 has a so-called T-type filter circuit including two inductance elements and one capacitor element, as in the conventional case. Then, as shown in FIG. 1, a cylindrical central conductor 8 and one capacitor element externally fitted to and electrically connected to a joint portion 9 in the central portion of the central conductor 8 in the axial direction are formed. The cylindrical capacitor 4, the non-linear conductors 2 and 3 which are two inductance elements formed at both ends of the cylindrical capacitor 4 excluding the central portion in the axial direction of the central conductor 8, and the non-linear conductor A resin 12 containing magnetic powder that covers the conductors 2 and 3 and a metal cap 10 that is electrically connected to one end of each of the non-linear conductors 2 and 3 and serves as an external terminal covered with the resin 12. , 11 and. The cylindrical capacitor 4 includes a pair of electrodes 5 and 6 on an inner peripheral surface and an outer peripheral surface of a dielectric 7, and the electrode 5 on the inner peripheral surface and a joint portion 9 of the central conductor 8 are electrically connected. Has been done.

As the center conductor 8, first, as shown in FIG. 2, a metal plate 13 having zigzag shape on both ends except for a central portion of a rectangle is prepared, and then rolled into a cylindrical shape in the width direction. It is made. As a result, as shown in FIG.
At the center of the central conductor 8 in the axial direction, a joint 9 with the capacitor element that projects outward is provided. At both ends of the joint 9, the non-linear conductor 2 serving as an inductance element,
3 is formed. The material of the metal plate 13 is, for example, phosphor bronze, which is relatively elastic.

The resin 12 is coated by molding or the like by adhering the resin 12 to both the inner and outer sides of the non-linear conductors 2 and 3.

When the metal caps 10 and 11 and the central conductor 8 are electrically connected, resistance welding, for example, is performed. The metal caps 10 and 11 are made of iron, for example, and the surfaces thereof are plated with silver to improve solderability.

As described above, since the inductance element forming a part of the chip type LC filter 1 of the present invention is composed of the non-linear conductors 2 and 3, the magnetic path becomes long and the inductance component becomes large. Moreover, the resistance component becomes large. Further, since the inductance element is covered with the resin containing the magnetic powder, the inductance component becomes larger. Therefore, the length of the inductance element can be shortened to reduce the size. Further, the central conductor 8 forming a part of the chip type LC filter 1 can be formed by rolling the metal plate 13 formed in a zigzag shape at both ends excluding the central portion of the rectangle in the width direction.

The present invention is not limited to the contents described in the above embodiments, and can be arbitrarily changed within a range not departing from the spirit of the present invention. For example, the non-linear conductors 2 and 3 of the central conductor 8 may be formed by electrically connecting a spirally formed wire to both ends of the joint 9 with solder or the like. Further, the shape and size of the capacitor element, the central conductor 8 and the like are arbitrary. For example, the shape of the capacitor element and the central conductor 8 is not limited to a cylinder, but may be a rectangular cylinder.

[0015]

As described above, according to the present invention, the inductance element constituting the chip type LC filter 1 can be reduced in size by shortening its length without reducing the inductance component or the resistance component. it can. Therefore, it is possible to provide a small chip-type LC filter 1 in which attenuation characteristics are not deteriorated even when the size of the inductance element is reduced, and resonance with other components is unlikely to occur.

[Brief description of drawings]

FIG. 1 is a partial vertical cross-sectional view of a part of one embodiment of a chip type LC filter of the present invention.

FIG. 2 is a plan view of a metal plate used as a center conductor which constitutes a part of the chip type LC filter of FIG.

3 is a perspective view of a central conductor which constitutes a part of the chip type LC filter of FIG. 1. FIG.

FIG. 4 is a partial vertical cross-sectional view in which a part of a conventional chip-type LC filter is a cross-section.

5 is a perspective view of a central conductor which constitutes a part of the chip type LC filter of FIG. 4. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Chip type LC filter 2, 3 ... Non-linear conductor 4 ... Cylindrical capacitor 5, 6 ... Electrode 7 ... Dielectric 8 ... Center conductor 9 ... Joint part 10, 11 ... Metal cap 12 ... Resin 13 ... Metal plate

Claims (2)

[Claims] 1. A capacitor element comprising a cylindrical center conductor and a pair of electrodes fitted on the central portion in the axial direction of the center conductor and electrically connecting one electrode of the center conductor to the center conductor. And an inductance element in which a non-linear conductor electrically connected to the central portion is formed on each of both ends except the central portion of the central conductor, and a resin containing magnetic powder covering the inductance element. A chip type LC filter comprising an external terminal electrically connected to an end of the inductance element. 2. The center conductor is formed by forming a metal plate formed in a zigzag shape on both ends except for a central portion in a length direction of a rectangle by rolling the metal plate in a width direction to form a cylindrical shape. The described chip type LC filter.