JPH0121554Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a high-withstand-voltage through-type ceramic capacitor used as a noise filter for a magnetron tube in a high-frequency power device, such as a microwave oven.

Background technology Conventionally, this type of capacitor (see Figures 1 and 2)
The center conductor 3, which penetrates through the dielectric 1, is attached and fixed to the upper electrode 1a of the dielectric 1 via the electrode fitting 2, and the rising flange 4a of the ground plate 4 is fixed in contact with the lower electrode 1b. An insulating case 5 and an insulating cover 6 are fitted and fixed above and below the ground plate 4.
It is constructed by filling and hardening an insulating resin 7 inside.

The insulating case 5 has a shape in which the side of the center conductor 3 on which the faston tab 3a is located is sealed with a lid 5a, and from this relationship, the insulating resin 7 is passed through the electrode fitting 2 and the ground plate 4 to the insulating case 5. A large number of through holes 2a, 2a..., 4b, are formed on each surface of the electrode fitting 2 and the ground plate 4 facing each electrode 1a, 1b of the dielectric 1 so as to fill the lid 5a side of the dielectric 1.
4b... is normally provided.

By the way, in order to effectively solve the problem of television reception interference caused by high-rise buildings in cities, television broadcasting using radio waves in the SHF band using artificial satellites is being carried out. In that SHF broadcast, the frequency overlaps with the frequency of the fifth high frequency that the microwave oven leaks,
It is expected that this fifth high frequency will cause reception interference. In particular, as the wavelength becomes shorter at frequencies in the SHF band, leakage of radio waves from the through holes 2a, 2a, . . . , 4b, 4b, . . . of the electrode fitting 2 and the ground plate 4 cannot be ignored.

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a feedthrough capacitor that can prevent radio wave leakage so as not to cause radio interference.

That is, in the feedthrough capacitor according to the present invention, the electrode fittings and the ground plate are formed on non-porous shielding surfaces except for the insertion portion of the center conductor, which is disposed through the dielectric on each surface facing the electrodes of the dielectric. When assembled, the dielectric is sealed with the electrode fitting and the ground plate.

Embodiment The following will be described with reference to FIGS. 3 to 5.

This feedthrough capacitor has basically the same structure as the capacitor shown in FIGS. 1 and 2. The dielectric body 10 is made of porcelain and has electrode layers 10a and 10b on the front and back sides, and an electrode fitting 11 is attached and fixed to the upper electrode 10a. This electrode fitting 11 has an opening 11a on the surface facing the electrode 10a of the dielectric 10, and by inserting the center conductor 12 into the opening 11a, the electrode 10a of the dielectric 10 can be inserted.
It is installed to connect to 0a. Further, a rising flange portion 13a of a grounding plate 13 is fixed in contact with the lower electrode 10b of the dielectric 10. This grounding plate 13 is fixed to other electrical connection members at the grounding flange portion 13b by screws or the like.
In addition to the screw hole 13c, an opening 13d is provided through which the axis of the center conductor 12 is inserted. Except for these openings 11a, 13c, and 13d, no openings are provided in the electrode fitting 11 and the ground plate 13.
The surface of the dielectric 10 facing each electrode 10a, 10b is formed of a non-porous shielding surface.

Further, in this feedthrough capacitor, an insulating case 14 and an insulating cover 15 are attached above and below with a grounding plate 13 in between. The insulating case 14 accommodates the dielectric 10 therein, and is attached by fitting and fixing the lower end side to the rising flange portion 13a of the ground plate 13 at the outer periphery. Further, the insulating cover 15 has an axis portion of the center conductor 12 inserted through its diameter, and its upper end side is fitted and fixed to the rising flange portion 13a of the ground plate 13 at its inner periphery. The insulating resin 16 is filled and hardened inside the insulating case 14 and the insulating cover 15 to protect the dielectric 10 from insulation.

In the feedthrough capacitor configured in this way, each surface of the electrode fitting 11 and the ground plate 13 facing each electrode 10a, 10b of the dielectric 10 is completely free except for the openings 11a, 13d through which the center conductor 12 is inserted. It is formed with a perforated shielding surface. Therefore, the radio waves generated by the dielectric 10 do not leak out from these shielding surfaces, and by sealing the dielectric 10 with the electrode fitting 11 and the ground plate 13, high frequency leakage can be effectively shielded. become able to. Incidentally, when this capacitor was compared with a conventional capacitor in terms of frequency attenuation, it was confirmed that there was a clear difference in frequency attenuation of about 1 to 10 GHz (see Figure 6).

In this capacitor, since the electrode fittings 11 and the ground plate 13 are formed of non-porous shielding surfaces, the insulating resin 16 is filled separately from the insulating case 14 and insulating cover 15 sides. For this reason, the insulating case 14 is formed into a simple long cylindrical shape without a lid. In this case, the effort of fitting the faston tab 12a of the center conductor 12 into the square hole 5b of the lid 5a as in the conventional example (see FIGS. 1 and 2) can be saved, and together with the filling direction of the insulating resin 7, This eliminates the risk of resin leaking from the hole 5b and causing electrical connection defects, and also eliminates the risk of electrical connections caused by fitting the Faston tab 3a into the square hole 5b too tightly and causing the soldered connection with the electrode fitting 2 to come off. This also eliminates the risk of poor connection. Furthermore, the square hole 5b
Due to dimensional variations when soldering and fixing the center conductor 3 and the dielectric 1, the square hole fitting part becomes the point of effort, and the connecting part between the electrode fitting 2 and the center conductor 3 becomes the fulcrum, and the center conductor 3 moves from side to side. Since it does not bend, and the pitch on the tip side can be easily determined, welding with a chiyoke coil or the like can be easily performed. In addition, since the insulating resin 16 is filled separately from the case side and the cover side, it is possible to relatively reduce the buildup of resin during degassing or injection, and the silicon tube 17 covering the center conductor 12 can be shortened. It becomes like this.

Effects of the invention As described above, the feedthrough capacitor according to the invention can prevent high frequency leakage;
Even if it is incorporated as a magnetron tube filter in a microwave oven, it will not cause interference with television reception.

[Brief explanation of the drawing]

Figure 1 is an exploded perspective view of a conventional feedthrough capacitor, Figure 2 is a side sectional view of the same capacitor, and Figure 3 is a side sectional view of the same capacitor.
The figure is an exploded perspective view of a feedthrough capacitor according to the present invention, Figures 4 and 5 are sectional views of the same capacitor, and Figure 6 is a cross-sectional view of the same capacitor.
The figure is a graph comparing the frequency attenuation rates of a feedthrough capacitor according to the present invention and a feedthrough capacitor according to a conventional example. 10...dielectric, 10a, 10b...electrode, 1
DESCRIPTION OF SYMBOLS 1... Electrode fitting, 12... Center conductor, 13... Grounding plate, 11a, 13d... Center conductor insertion part.

Claims (1)

[Scope of utility model registration request] A penetrating type characterized in that each surface facing the electrode of the dielectric material is composed of an electrode fitting and a ground plate formed on a non-porous shielding surface, except for the insertion part of the center conductor which is arranged through the dielectric material. capacitor.