JPS602652Y2 - electromagnetic interference filter - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electromagnetic interference filter suitable for use by being attached to a printed circuit board or the like.

Conventionally, as an electromagnetic interference filter, a cylindrical dielectric body 1 is provided, as shown in FIG. External electrodes 3 are formed on the outer peripheral surface of the body 1 to face the internal electrodes 2a and 2b, respectively, and ferrite beads 4 are fitted inside the dielectric 1, and the internal electrodes 2a are connected to each other by eyelets 5 and 5. , 2b are electrically connected to the through shaft 6, and a mounting bracket 7 is fixed to the external electrode 3 by soldering or the like, and as shown in FIG. 2, the inductance L formed by the ferrite beads 4 and the internal electrode 2a are Lc? An r-type filter circuit is known.

However, in order to attach the electromagnetic interference filter having the above configuration to a printed circuit board, the printed circuit board must be provided with a hole into which the electromagnetic interference filter is inserted, and the through shaft 6 must be bent into a U-shape or connected to another lead wire. , fit the electromagnetic interference filter into the above hole, and solder the mounting metal 7 to the ground part of the printed circuit board. At the same time, bend the through shaft 6 or use another lead wire etc. to connect the printed circuit board. Alternatively, as shown in FIG. 3, the electromagnetic interference filters 9° . After soldering . First, there was the problem that installation was very time-consuming.

In addition, the electromagnetic interference filter shown in FIG.
Since it has a structure in which the ferrite beads 4 are inserted into the inside of the dielectric material 1, its shape becomes large, but in order to form the internal electrodes 2at2b inside the dielectric material 1, a less efficient method such as brush painting must be used. Moreover, these internal electrodes 2
Since a and 2b must be electrically connected to the through shaft 6 using the eyelets 5 and 5, respectively, there is a problem that the structure is complicated and mass productivity is low.

The present invention has been made to solve the above-mentioned problems in conventional electrode interference filters, and is provided with a ferrite core having a through hole passing through a through shaft formed in a roughly U-shape. The through-shafts are directly attached to a printed circuit board, etc. by inserting them into the through-holes of the ferrite cores, and then passing both of the leg parts through the capacitor and passing them from one side of the metal board to the other.
In order to simplify the installation, both legs of the penetrating shaft passed through the ferrite core are passed through the capacitor, respectively.
It is an object of the present invention to provide an electromagnetic interference filter whose assembly and structure are simplified.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 4, 11 is a metal substrate, 12 and 12 are capacitors each having a through hole 13.13 in the shaft center, 14 is a through shaft having a roughly U-shape, and 15 is a ferrite core.

A pair of opposing sides of the metal substrate 11 are formed with ground terminals 16.16 for mounting a printed circuit board and protrude downward, and a pair of round holes 17 are formed in the metal substrate 11. , 17 are formed, and these round holes 17, 17
The capacitors 12 and 12 are fitted into the capacitors 12 and 12, respectively.

The capacitors 12.12 are all feedthrough capacitors having the same configuration, and include a dielectric 12a having a through hole 13 in the axial center, an electrode 12b formed on the inner peripheral surface of the dielectric 12a, and a dielectric Electrode 1 formed on the outer peripheral surface of 12a
2c, the electrode 12c of the capacitor 12, 12,
12c is fixed to the metal substrate 11 with solder 18.18.

On the other hand, the ferrite core 15 has a large inductance and is formed to have a substantially elliptical cross-sectional shape so that both legs 14ai4b of the through shaft 14 can be inserted at once. Two insertion holes 1 into which the legs 14a and 14b of the
5a and 15b.

After both legs 14a and 14b of the through shaft 14 are inserted into the insertion holes 15a and 15b of the ferrite core 15, respectively, the legs 1 are inserted into the through hole 13.13 of the capacitor 12.12.
4a, 14b, and connect both legs 14a, 14b to the electrodes 1 of the capacitors 12, 12 with solder 19.19.
2b and 12b, respectively.

If the electromagnetic interference filter has the above configuration, the capacitor 12
．． With the capacitance of 12 and the inductance of the ferrite bead 15, a π-type electromagnetic interference filter similar to that shown in FIG. 2 can be obtained, but as can be seen from FIG. Since both protrude toward the ground terminal 16 and 16 side of the metal board 11,
The electromagnetic interference filter shown in FIG. 4 is mounted on a printed circuit board (not shown).

), the above-mentioned both legs 14a. 14b and the ground terminals 16 and 16 may be inserted into the holes of the printed circuit board and soldered, making attachment to the printed circuit board very easy.

Further, as shown in FIG. 5, on one metal substrate 11,
A large number of filter units 20 consisting of capacitors 12, 12, through shafts 14 and ferrite beads 15. ...
, 20, a large number of filter units 20., 20 can be installed at once. ..., 20 can be compactly attached to a printed circuit board.

In addition, in order to assemble the electromagnetic interference filter shown in FIGS. 4 and 5, both legs 14a of the through shaft 14 are assembled.

14b into the insertion holes 15a and 15 of the ferrite core 15, respectively.
b, and then insert the capacitors 12.12 into both leg portions 14ai4b, respectively.
12 into the round holes 17, 17 of the metal substrate 11, respectively, and then the metal substrate 11 was placed in a solder jet tank (not shown).

), making assembly very simple.

In this case, it is only necessary to insert one ferrite core 15 into both legs 14a, 14b of the through shaft 14 (compared to the case where separate ferrite cores are inserted into both legs 14a, 14b, respectively). The core installation process is also reduced.

Although the basic embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, as the capacitor 12, as shown in FIG. A dielectric body 12a' having a protrusion 21 that fits into the round hole 17 is used, and electrodes 12b' and 12C' are formed on one and the other surface of the dielectric body 12a', respectively. It may also be soldered to the metal substrate 11.

In addition, in FIGS. 4 to 6, the earth terminal 16.1
6 is not particularly necessary if the metal plate 11 is directly connected to the ground electrode of the printed circuit board.

As is clear from the above detailed explanation, the present invention has been proposed by inserting both legs of a penetration shaft formed into a roughly U-shape into insertion holes provided substantially parallel to a ferrite core, and then Since the capacitor is inserted through the capacitor from one side of the metal board to the other, when attaching the electromagnetic interference filter to a printed circuit board, the legs must be inserted into the holes provided in the printed circuit board and soldered. This makes it extremely easy to mount the electromagnetic interference filters on a printed circuit board, and it is also possible to compactly mount the required number of electromagnetic interference filters on the printed circuit board at once.

In this case, the arrangement of the filter unit with respect to the metal substrate can be arbitrarily set according to the circuit pattern of the printed circuit board.

Furthermore, unlike conventional electrode interference filters, the electromagnetic interference filter according to the present invention does not use a special capacitor in which two inner surface electrodes are formed on the inner peripheral surface of a cylindrical dielectric. There is no need for eyelets etc. to connect the through shaft and the structure is extremely simple.
This has great effects, such as no need to use a special capacitor and mass production becomes extremely easy.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional electrode interference filter, Fig. 2 is an equivalent circuit diagram of Fig. 1, Fig. 3 is an installation explanatory diagram of Fig. 1, and Fig. 4 is a sectional view of a conventional electrode interference filter.
The figure is a longitudinal sectional view of an electromagnetic interference filter according to the present invention, FIG. 5 is a plan view of an embodiment in which a plurality of filter units are assembled on a metal substrate, and FIG. 6 is a longitudinal sectional view of a modification of FIG. 4. be. 11...Metal plate, 12...Capacitor, 13...Through hole, 14...Through shaft,
14a, 14b... Legs, 15... Ferrite core.

Claims (1)

[Scope of utility model registration request] At least a pair of holes are provided in one metal substrate, capacitors each having a through hole in the axial center are arranged concentrically with the holes, and one electrode of each capacitor is fixed to the metal substrate, A through shaft formed in a roughly U shape and a ferrite core having a pair of through holes into which both leg portions of the through shaft are respectively fitted are provided, and after the both leg portions are inserted into the respective through holes of the ferrite core, the both legs are inserted. An electrode interference filter characterized in that the electrodes of the capacitor are inserted into the through holes of the capacitor, the legs are penetrated from one side of the metal substrate to the other side, and the other electrode of the capacitor is fixed to the legs.