JPS6114176Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a noise filter, and more particularly to the structure of a noise filter in which filter components are housed in a cylindrical metal case and provided with external connection terminals.

FIG. 1 and FIG. 2 are diagrams respectively showing the external appearance and internal structure of this type of noise filter before it is filled with insulating resin.

This type of noise filter configures a filter circuit by connecting a chiyoke coil 1, a capacitor 2, etc. with their lead wires to an external connection plate terminal 4 inserted into a terminal holding plate 3 by soldering. It is housed in a cylindrical case 5. The case 5 is made of aluminum and is molded with mounting screws 6 integrally provided on the bottom surface, and the inner surface is insulated with insulating paper 7 or the like.
When storing in the case 5, the holding plate 3 is stored so as to be located slightly below the open end of the case 5, and the ground terminal 8 is directly connected to the case 5. Next, an insulating resin is temporarily filled into the case 5 to the extent that the holding plate 3 is covered, and is solidified. Furthermore, a noise filter is manufactured by carefully filling and solidifying resin on top of the resin so that the plate-shaped terminal 4 protrudes from the resin surface by a predetermined distance.

However, this structure requires a large amount of insulating resin and needs to be filled and solidified twice, resulting in poor filling efficiency. Further, the final filling requires skill and great care, and there are drawbacks such as overflowing the resin from the case and troublesome removal of the resin if it adheres to the outer surface of the case.

An object of the present invention is to provide a noise filter that eliminates these drawbacks.

The present invention provides a noise filter in which a filter circuit is constructed by connecting circuit elements such as coils and capacitors to external connection terminals inserted into a terminal holding plate and housed in a bottomed cylindrical case. The opening is closed with a cover plate through which the external connection terminal is passed, and an insulating resin is solidified to such an extent that the terminal holding plate is buried in the cylindrical case with the cover plate at the bottom. Features.

Examples of the present invention will be described below.

FIG. 3 is an external view of an embodiment of the cover plate used in the noise filter according to the present invention. Circular lid plate 9
is made of an insulating elastic material, has a notch or elongated through hole 10 at a predetermined location, through which an external connection terminal is inserted without leaving a gap, has a diameter slightly larger than the inner diameter of the case, and has a chamfered bottom edge. Processed.

FIG. 4 is a diagram showing a state in which the cover plate 9 shown in FIG. 3 is fitted into the case 5. That is, after insulating the inner surface of the case 5 with insulating paper 7 in the same manner as shown in FIG. 2, the coil 1, capacitor 2, terminal holding plate 3, etc. connected to form a filter circuit are housed. The terminal holding plate 3 in the case 5 is supported by the lead wire connected to the plate-shaped terminal 4, which is a thick wire. Then, the case 5 with the ground terminal 8 connected is filled with insulating molten resin 11 in an amount of about 1/4 to 1/5 of the capacity of the case 5. Immediately after filling (before the viscosity of the resin increases), the plate terminal 4 is inserted into the through hole 10 of the cover plate 9 so that the opening end of the case 5 and the top surface of the cover plate 9 are almost on the same plane. Press fit and seal the case.

Thereafter, as shown in FIG. 5, the case 5 is turned upside down and placed with the plate terminal 4 side facing downward. As a result, the resin 11 other than those attached to the inner bottom of the case 5, the coil 1, the insulating paper 7, etc. completely immerses the retaining plate 3 on the cover plate 9 side, and accumulates to a depth sufficient to cover the ground terminal 8 as well. Therefore, in this state, resin 1
1 solidifies and a noise filter is completed. Since there is no gap between the plate terminal 4 and the through hole 10 of the cover plate 9, there is no resin leakage. In this way, since the amount of resin 11 filled is small, it can be filled in a short time, and there is no fear of the resin 11 being attached to the outer surface of the case 5. Furthermore, even if the amount of resin is small, the terminal holding plate 3 is buried in the resin 11, and the ground terminal 8 is in the resin 11, so the solidified resin 11 is prevented from rotating within the case 5. The terminal holding plate 3 is also fixed, and the plate-shaped terminal 4 is reinforced in the same manner as in the case of the conventional case where the terminal is completely filled with resin. Of course, the cover plate 9 is also fixed by the adhesive action of the solidified resin 11.

The thickness of the cover plate 9 is determined when the diameter of the case 6 is 50 mm.
If the diameter is about 3 mm, sufficient sealing performance can be obtained and the warping of the cover plate 9 will be small.

As explained above, according to the present invention, the amount of insulating resin used can be significantly reduced, the efficiency of filling work can be increased, and the terminal surface can be finished uniformly and neatly. It is possible to provide a high-quality noise filter at a low cost, with terminals that can be reinforced like conventional ones without leaking out of the case.

[Brief explanation of the drawing]

1 and 2 are an external view and a partially cutaway front view of the noise filter before being filled with insulating resin, and FIG. 3 is an external view of an embodiment of the cover plate used in the noise filter according to the present invention. FIG. 4 is a partially cutaway front view showing the noise filter according to the present invention in a state immediately after the cover plate is fitted, and FIG. 5 is a partially cutaway front view showing the state when the resin is solidified. In the figure, 1...coil, 2...capacitor, 3...
...Terminal holding plate, 4...Plate terminal for external connection, 5...
...Case, 6...Mounting screw, 7...Insulating paper, 8...
...Earth terminal, 9...Lid plate, 10...Through hole, 11
...Insulating resin.

Claims (1)

[Scope of utility model registration request] In a noise filter in which a filter circuit is constructed by connecting circuit elements such as coils and capacitors to external connection terminals inserted into a terminal holding plate and housed in a bottomed cylindrical case, the opening of the cylindrical case is The noise is characterized in that the external connection terminal is closed with a penetrating cover plate, and an insulating resin is solidified in the cylindrical case to such an extent that the terminal holding plate is buried with the cover plate at the bottom. filter.