JPS6022609Y2 - Feedthrough capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention primarily relates to a feedthrough capacitor suitable for use in an antenna input circuit of a TV receiver.

In TV receivers, in order to prevent video disturbances such as coasting or reflected images caused by reflection of signal radio waves, as well as improve transmission function and prevent round-trip reflection of signals on feeder lines, conventional As shown, an antenna input circuit unit has been used in which a coupling capacitor C1 is connected to the center conductor of a coaxial cable, and a bypass capacitor C2 is connected to the outer conductor for passing unnecessary frequency signals.

FIG. 2 shows a conventional example of a feedthrough capacitor used as a bypass capacitor C2 of this antenna input circuit unit. The through terminal 3 passed through the through hole 1 is fixed by soldering or the like, and the electrode 2b of the ceramic capacitor 2 is soldered to the internal stepped surface 4a of the external terminal fitting 4. The structure is such that insulating resins 5 and 6 are filled around the ceramic capacitor 2 to improve withstand voltage and moisture resistance.

However, with the above-described structure, in order to connect a coaxial cable etc., the user must prepare, for example, an F-type plug, phono jack, etc., and insert it into the through terminal 3. Handling becomes troublesome and costs high, and soldering of coaxial cables and coupling capacitors (C1 in Figure 1) to F-type connectors, etc. requires work, so it is difficult to handle them when unitizing them as an antenna input circuit. Assembly work becomes troublesome.

A feedthrough capacitor shown in FIG. 3 has been proposed to eliminate the drawbacks of the feedthrough capacitor described above.

In this feed-through type capacitor, the feed-through terminal 3 includes a stepped cylindrical outer conductor 7 and an internal contact 8 passing through the inner diameter of the outer conductor 7. The large diameter portion 7a is fixed to the electrode 2a of the ceramic capacitor 2 by soldering or other means, and the inner contact 8 is inserted into the inner diameter portion of the outer cylindrical conductor 7 while being fitted inside the insulating cylindrical body 9. It is.

With such a structure, by appropriately selecting the diameter, shape, etc. of the large diameter portion 7a of the outer cylindrical conductor 7, an external connector such as an antenna jack can be connected to the outer conductor by connecting the outer conductor to the large diameter portion 7a of the outer cylindrical conductor 7
In addition, since the center conductor can be connected to the internal connector 8 and coupled directly, there is no need for the user to prepare an F-type connector or phono jack, etc., making handling convenient and inexpensive. become.

In this example, two annular ceramic capacitors 2゜2 with through holes 1 and 1 opened on the electrode forming surface are connected to the through hole 1.
, 1 are stacked in series and fixed together.

With such a structure, the voltage applied between the outer cylindrical conductor 7 and the external terminal fitting 4 constituting the through terminal 3 is divided by the magnetic capacitor 2.2, so that the withstand voltage is improved.

In addition, even if one of the ceramic capacitors 2, 2 is destroyed by lightning or the like, the necessary insulation and capacitance can be secured with the other remaining capacitors, resulting in a double protective insulation structure.
Safety and reliability are improved.

However, since the insulating resins 5 and 6 are in direct contact with the ceramic capacitor 2, the outer cylindrical conductor 7, and the external terminal fittings, the shrinkage ratio is one phase or more smaller than this.
Due to thermal shock during curing and shrinkage of the insulating resin 5, 6 and the ceramic capacitor 2.
There is a drawback that gaps, cracks, or peeling occur at the interface between the outer cylindrical conductor 7 and the external terminal fitting 4, and the withstand voltage characteristics, moisture resistance, etc. are likely to deteriorate.

This kind of drawback exists even in the type shown in Figure 2.
The same is true.

In order to eliminate the above-mentioned drawbacks, a feedthrough capacitor shown in FIG. 4 has been proposed.

This feedthrough capacitor has a through hole 1 of a ceramic capacitor 2.
A heat-shrinkable insulating tube 10 is placed over the small-diameter portion 7b of the outer cylindrical conductor 3 that penetrates inside, and the heat-shrinkable insulating tube 10 alleviates thermal shock during curing and shrinkage of the insulating resin 6 or during a heat cycle test. This is expected to improve voltage resistance and moisture resistance.

However, when assembling this feedthrough capacitor,
First, the outer cylindrical conductor 7 constituting the through terminal 3 is fixed by soldering to the electrode 2a of the ceramic capacitor 2, and then the small diameter portion 7b of the outer cylindrical conductor 7 is covered with the heat-shrinkable insulating tube 10, and then,
The assembly process is complicated because the insulating cylinder 9 filled with the insulating resin 5.6 and having the internal contact 18 inserted therein must be inserted into the inner diameter part of the small diameter part 7b of the outer cylinder conductor 7 from the end thereof. There was a drawback that made it annoying.

In addition, due to the application of safety standards, this type of feed-through capacitor has regulations on the creepage distance and space distance between the internal contact 8 and the external terminal fitting 4, and is designed for miniaturization and improved withstand voltage. is the key point.

Conventionally, therefore, the small diameter portion 7b of the outer cylinder conductor 7 was covered with a heat-shrinkable insulating tube 10, but even with this structure, the above-mentioned spatial distance was not completely protected, and it was difficult to improve the withstand voltage.
There were limits to miniaturization.

The present invention eliminates the above-mentioned drawbacks, requires less assembly man-hours, and
The purpose of the present invention is to provide a feedthrough capacitor that is inexpensive, has a high withstand voltage, and can be miniaturized.

In order to achieve this object, the present invention connects a through terminal penetrated through the through hole to one of the electrodes of a capacitor having a through hole opened in the electrode forming surface, and connects the other electrode to an external terminal metal fitting. In the feedthrough capacitor, the feedthrough terminal includes an outer cylindrical conductor fixed to one of the electrodes, and a contact provided within the inner diameter of the outer cylindrical conductor,
A part of the outer periphery of the outer cylindrical conductor passing through the through hole and around the contact within the inner diameter portion of the outer cylindrical conductor are covered with a heat-shrinkable insulating resin.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The content of the present invention will be specifically described below with reference to the accompanying drawings, which are examples.

FIG. 5 is a front sectional view of the feedthrough capacitor according to the present invention.

In the figures, the same reference numerals as in FIGS. 2 to 4 indicate functionally identical components.

11 is a heat-shrinkable insulating resin, and the small diameter portion 7 of the outer cylindrical conductor 7
b, and is provided so as to cover the outer periphery of the conductor 7 and fill the space around the contact 8 in the inner diameter portion of the outer cylindrical conductor 7.

With this structure, thermal shock during curing and shrinkage of the insulating resin 6 or during a heat cycle test is alleviated by the heat-shrinkable insulating resin 11 inside and outside the outer cylinder conductor 7, so that the insulating resins 5, 6 The occurrence of gaps and cracks at the interface between the capacitor and the ceramic capacitors 2, 2 is prevented, and the withstand voltage characteristics and moisture resistance are improved.

In this embodiment, the heat-shrinkable insulating resin 11 has an inner cylindrical portion 11A through which the contact 8 passes and is inserted into the inner diameter portion of the outer cylindrical conductor 7, and a small diameter portion 7b of the outer cylindrical conductor 7 from the tip end. An outer cylindrical portion 1 that is a cover and is inserted into a through hole 1 of a ceramic capacitor 2
1B are coaxially integrated.

With this structure, when assembling the feedthrough capacitor, with the outer cylindrical conductor 7 soldered to the electrode 2a of the ceramic capacitor 2, a contact is inserted from the tip of the small diameter portion 7b to the inner cylindrical portion 11A. Heat-shrinkable insulating resin 11 with 8 inserted
By simply fitting the heat-shrinkable resin 11 into the small-diameter portion 7b and the contact 8 into the outer cylinder conductor 7, the assembly process is simplified and shortened, and the assembly process is reduced. Cost becomes cheaper.

Moreover, since the creepage distance from the contact 8 to the external terminal fitting 4 is a relatively long path along the end face of the heat-shrinkable insulating resin 11, the withstand voltage is improved and miniaturization is possible.

FIG. 6 shows a sectional view of another embodiment of the feedthrough capacitor according to the present invention.

The feature of this embodiment is that the inner cylinder 11A and the outer cylinder 11B are hollowed out with heat-shrinkable insulating resin 11 so that the tip of the small diameter portion 7b of the outer cylinder conductor 7 can be extended and covered. The reason is that it was installed.

With such a structure, the creepage distance from the external terminal fitting 4 to the contactor 8 increases by the extension a, so that the withstand voltage is further improved.

In the above description, a feedthrough capacitor having a double protection insulation structure was used as an example, but the present invention can also be applied to a feedthrough capacitor having a single capacitor type.

As described above, in the present invention, a through terminal penetrated through the through hole is connected to one of the electrodes of a capacitor having a through hole opened in the electrode forming surface, and the other electrode is connected to an external terminal fitting. In the feedthrough capacitor, the feedthrough terminal includes an outer cylindrical conductor fixed to one of the electrodes, and a contact provided within an inner diameter portion of the outer cylindrical conductor, and the feedthrough terminal extends through the through hole. Since the outer periphery of the outer cylindrical conductor and the area around the contact within the inner diameter of the outer cylindrical conductor are covered with heat-shrinkable insulating resin, the number of assembly steps is small, the cost is low, and It is possible to provide a feedthrough capacitor that has a high withstand voltage and can be miniaturized.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of an antenna input circuit, Figures 2 to 4 are cross-sectional views of conventional feedthrough capacitors, Figure 5 is a cross-sectional view of a feedthrough capacitor according to the present invention, and Figure 6 is a similar cross-sectional view of a feedthrough capacitor according to the present invention. FIG. 1...Through hole, 2...Magnetic capacitor, 2a. 2b...Electrode, 3...Through terminal, 4.
...External terminal fitting, 5,6...Insulating resin, Contactor, 11...Heat-shrinkable insulating resin, 11A... Inner cylinder body, 11B...
Outer cylinder.

Claims (4)

[Scope of utility model registration request] (1) A feed-through type capacitor in which a through-hole terminal passed through the through-hole is connected to one of the electrodes of the capacitor having a through-hole opened in the electrode forming surface, and the other electrode is fixed on an external terminal fitting, The through terminal includes an outward conductor fixed to one of the electrodes and a contact provided inside the inner diameter portion of the outer cylinder conductor, and includes a part of the outer periphery of the outer cylinder conductor passing through the through hole and the outer cylinder. A feed-through capacitor characterized in that a heat-shrinkable insulating resin covers the area around the contact within the inner diameter portion of the conductor. (2) The heat-shrinkable insulating resin is more powerful than a structure in which an inner cylinder part that covers the circumference of the contact and an outer cylinder part that covers a part of the outer periphery of the outer cylinder conductor are connected coaxially and integrally. A feedthrough capacitor according to claim 1 of the utility model registration claim. (3) The feedthrough capacitor according to claim 1, wherein the outer cylindrical conductor has an extended tip portion of the portion covered with the heat-shrinkable insulating resin. (4) The capacitor is more powerful than a structure in which at least two capacitors each having a through hole in the electrode forming surface are stacked in series with the through holes aligned. , the feedthrough capacitor according to item 2 or 3.