JPS5915065Y2 - High voltage feedthrough capacitor - Google Patents

Description

[Detailed description of the invention] The present invention relates to a high-voltage feed-through type capacitor used as a noise filter for high-frequency, high-power equipment, such as microwave ovens, magnetrons of broadcasting equipment, or X-ray tubes. This relates to a mounting structure that prevents leakage of electromagnetic waves from the parts.

Recently, high-power electromagnetic waves in the UHF and VHF bands have come to be used not only in industrial equipment such as broadcasting equipment, X-ray medical equipment, but also in consumer equipment such as microwave ovens, and as their usage increases. , Prevention of noise pollution caused by electromagnetic waves leaking from these devices has become an important issue.

In order to prevent such noise pollution, various noise filters have been proposed.

Figure 1 shows a conventional example of a high voltage feed-through type capacitor used as a component of this type of noise filter.
Mutually independent electrodes 4 and 5 and a common electrode 6 are provided around the through holes 2 and 3 on both sides of the dielectric ceramic 1 having through holes 2 and 3 in the thickness direction, and the common electrode 6 is connected to a grounding metal fitting. The through hole is fixed to the floating part 7 a of the dielectric ceramic 1 and extends through the through holes 2 and 3 of the dielectric ceramic 1 and the through holes 9 and 10 of the grounding fitting 7 to the other side of the grounding fitting 7. Conductor 11.1
2 is fixed to the electrodes 4 and 5 through electrode connectors 13 and 14 by means such as soldering.

A cylindrical insulating cover 8 made of an insulating material such as synthetic resin is inserted into the inner diameter of the other side of the grounding fitting 7 from which the through conductor 11.12 is led out so as to surround the through conductor 11.12. It is.

Furthermore, the bottom part of the insulating cover 8, the dielectric ceramic 1, the electrode connector 13.14, and the portion of the through conductor 11.12 covered with the elastic insulating tube 15.16 are coated with an insulating resin 17 such as epoxy resin. ing.

FIG. 2 shows a partial sectional view of a magnetron device such as a microwave oven incorporating the above-mentioned high voltage feedthrough capacitor.

In the figure, reference numeral 18 denotes an anode having a known internal structure, and cooling fins 19 made of AI, Cu, etc. are attached to the outer periphery of the anode for heat radiation.

20 is a permanent magnet, and its magnetic flux is guided to a working space (not shown) in the center of the anode 18 by yokes 20a and 20b.

Reference numeral 21 denotes an antenna, and the antenna 21 is supported by an insulating cylinder 22 made of porcelain, glass, etc., and converts high-frequency vibrations generated in a cavity resonator (not shown) formed inside the anode 18 into electrons. Heats food by emitting radiation into an oven such as a microwave.

Further, a cathode (not shown), which is arranged in the center of the anode 18, forms a working space with the anode 18, and supplies electrons necessary for sustaining high-frequency vibration, is connected to a plurality of cathode support rods (not shown). Fixed.

One end of this cathode support rod is pulled out to the end opposite to the antenna 21 and fixed to an insulating bottomed cylinder 23 made of ceramic or the like, where it is brazed to one end of a cathode conductor 24. .

25 is an insulator, and one end of this insulator 25 is fixed to the yoke 20b with a screw.

Further, on the other end of this insulator 25, there is a mounting terminal 24a which is pressure-welded to the other end of the cathode conductor 24, and a mounting terminal 24a which is pressure-welded to one end of an inductor 26 which is made of a ferrite rod or the like wound with an insulated copper wire in a coil shape. The terminal 26 a is fixed with a screw 27 .

The other end of this inductor 26 is connected to one end of the through conductor 11.12 of the high voltage feedthrough capacitor 28 through a mounting terminal 26.
It is fixed by b.

The high voltage feedthrough capacitor 28 has the structure shown in FIG.
At the same time, the peripheral edge of the grounding metal fitting 7 is brought into surface contact with the edge part 31 forming the through hole 30 of the shield case 29, and both are fixed with screws 32.

33 is a lid, and the upper end opening 29 of the shield case 29
a and fix it with screws 34.

Cooling fins 19 are provided on the upper surface 33a of this lid 33.
A large number of air circulation holes 35 are drilled through which air for forced air cooling passes.

In the above magnetron device, an inductor 26 and a high voltage feedthrough capacitor 2 are connected to a cathode circuit (not shown).
8 are inserted and connected in series, during operation of this magnetron device, high frequency noise components propagating from the cathode ray circuit to the external power supply circuit are attenuated by the filtering action of the inductor 26 and the high voltage feedthrough capacitor 28.

However, in conventional high-voltage feed-through capacitors, the mounting surface of the grounding fitting 7 that contacts the shielding case 29 is formed in a flat shape, and the connection of the grounding fitting 7 to the shielding case 29 is shown in an enlarged view in FIG. As such, since it has to be flat, there is a problem in that electromagnetic waves leak to the outside through a small gap that occurs at the joint between the two.

Ground metal 7 and shield case 29 to prevent electromagnetic wave leakage.
Measures have been taken to apply conductive paint or interpose conductive tape between the I couldn't.

SUMMARY OF THE INVENTION The present invention aims to eliminate the above-mentioned drawbacks of the conventional capacitor and provide a high-voltage feedthrough capacitor having a structure that can constitute a nearly complete electromagnetic wave leakage prevention mechanism when in use.

In order to achieve the above object, the present invention provides a ceramic capacitor having a through conductor passed through it on one side of a grounding fitting, and an insulator surrounding the lead-out portion of the through conductor on the other side of the grounding fitting. A high voltage feed-through type container is characterized in that the other surface of the grounding fitting is provided with a stepped inner diameter portion having a gap between it and the outer circumferential surface of the insulator.

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. 4 is a sectional view of a high voltage feedthrough capacitor according to the present invention.

In the figures, the same reference numerals as in FIG. 1 indicate functionally identical components.

In this embodiment, the floating part 7a of the grounding fitting 7 is narrowed down to two stages, and a stepped inner diameter part 7b having a larger inner diameter is provided continuously to the inner diameter part of the floating part 7a into which the insulating cover 8 is fitted. It has a similar structure.

Therefore, a gap g1 is formed between the outer peripheral surface of the insulating cover 8 and the inner diameter portion 7b based on the difference in the inner diameter of the floating portion 7a and the inner diameter portion 7b.

With the above structure, when it is incorporated as a noise filter in a magnetron device as explained in FIG. 2, the inner diameter part 7 of the high voltage feed-through type capacitor is
The inner edge 29b of the shield case 29, which has been previously bent inward to match the shape of b, is fitted into the inner diameter part 7b of the high voltage feedthrough capacitor, and the joint surface between the shield case 29 and the grounding fitting 7 is It is possible to almost completely prevent leakage of electromagnetic waves at the bonding surface by forming the electrodes in a step-like manner.

Furthermore, there is no need for conductive paint, tape, etc., and it is only necessary to fit the grounding fitting 7 to the shield case 29, so a complete electromagnetic wave leakage mechanism can be achieved without increasing the number of parts or complicating the assembly. Can be configured.

Further, since it is only necessary to process the inner edge 29b of the shield case 29 into a shape that matches the inner diameter portion 7b of the grounding metal fitting 7, the process of the shield case 29 is also easy.

As described above, the present invention provides a high-voltage capacitor in which a ceramic capacitor having a through conductor is provided on one side of a grounding fitting, and an insulator surrounding the lead-out portion of the through conductor is provided on the other side of the grounding fitting. The feed-through capacitor is characterized in that the other surface of the grounding fitting is provided with a stepped inner diameter portion having a gap between it and the outer peripheral surface of the insulator. By simply providing a part on the case side that fits inside the inner diameter part, a stepped joint surface can be formed between the grounding fitting and the shielding case, which can almost completely prevent leakage of electromagnetic waves at the joint surface. A feedthrough capacitor can be provided.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional high voltage feed-through type capacitor, Fig. 2 is a partial cross-sectional view of a magnetron device incorporating this high voltage feed-through type capacitor, Fig. 3 is a diagram illustrating the drawbacks of the conventional type, and Fig. 4 is a cross-sectional view of a conventional high voltage feed-through type capacitor. The figure is a sectional view of a high voltage feedthrough capacitor according to the present invention, and FIG. 5 is a diagram illustrating its effect. 1...Magnetic capacitor, 7...Grounding metal fitting, 7a...Floating part, 7b...Inner diameter part, 8...Insulating cover, 11゜12・・・・・・
Through conductor.

Claims (1)

[Scope of utility model registration request] A high-voltage feed-through capacitor in which a magnetic capacitor having a through conductor is provided on one surface of the grounding metal fitting, and an insulator surrounding the lead-out portion of the through-hole conductor is provided on the other side of the grounding metal fitting. A high voltage feed-through capacitor, characterized in that a stepped inner diameter portion having a gap between the other surface and the outer peripheral surface of the insulator is provided.