JP2007018940A - High-voltage feed-through capacitor and magnetron - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-voltage feed-through capacitor and a magnetron, wherein filling amount of an insulation filler is reduced, stress relaxation accompanying the reduction of filling amount of the resin, enhancement of reliability, and furthermore cost reduction are achieved. <P>SOLUTION: Grounding fittings 3 have a floating part 32 on one face side, and the floating part 32 has a recessed part 30 in the inside. The inner face of the recessed part 30 has a first standing part 34, a flange part 35, and a second standing part 36. An insulation cover 6 has a stepped part 61 at the end part, and is fitted into the inside of the recessed part 30 of the ground fittings 3 with the stepped part 61 as the tip, while the stepped part 61 covers at least partially the inner face of the flange part 35. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-voltage feedthrough capacitor and a magnetron using the high-voltage feedthrough capacitor.

  This type of high-voltage feedthrough capacitor is incorporated in a magnetron as a filter that removes unnecessary radiation generated during the oscillation operation of the magnetron, for example, and a general structure is disclosed in, for example, Patent Document 1 ing.

  In this type of high voltage feedthrough capacitor, a high voltage is applied between the grounding metal fitting and the through conductor (center conductor), so that a sufficient withstand voltage must be ensured between the two. Conventionally, as shown in Patent Document 1, etc., as a means for this, an insulating filler made of insulating resin or the like is filled in a large volume from the inside of the capacitor through hole to the inside of the raised portion of the grounding metal fitting. It was.

For this reason, the amount of the insulating filler used is inevitably increased, and it is easily affected by the thermal expansion / contraction of the insulating filler, resulting in the generation of stress due to the expansion / contraction of the insulating filler and the accompanying decrease in the withstand voltage. I was invited. In addition, the high cost due to an increase in the amount of insulating filler used cannot be ignored.
JP-A-8-78154

  An object of the present invention is to provide a high-voltage feedthrough capacitor and a magnetron that reduce the filling amount of the insulating filler, relieve stress and improve the reliability accompanying the reduction of the resin filling amount, and further reduce the cost. It is to be.

  In order to solve the above-described problem, a high-voltage feedthrough capacitor according to the present invention includes a grounding fitting, a capacitor, a through conductor, an insulating cover, and an insulating filler. The grounding metal has a raised portion on one side. The raised portion has a concave portion on the other surface side, and the inner surface of the concave portion is continuous with the first rising portion, the flange portion that continues to the first rising portion and narrows the concave portion, and the flange portion. And a second rising portion that rises.

  The capacitor has two divided electrodes on one surface side, a common electrode on the other surface side, is mounted on one surface of the raised portion, and the common electrode is connected to the one surface of the raised portion. . There are two through conductors, each of which penetrates the capacitor and the grounding metal and is connected to the divided electrode. The insulating cover has a cylindrical shape and is fitted into the inner surface of the concave portion of the grounding metal so as to surround the through conductor.

  The configuration described above is the basic structure of this type of high-voltage feedthrough capacitor. The feature of the present invention is that, in the structure described above, a device is added to the shape of the end portion of the insulating cover that is fitted into the recess of the grounding metal fitting. That is, in the present invention, the insulating cover has a stepped portion at an end, and is fitted into the inner surface of the concave portion of the ground metal fitting, with the stepped portion being a tip, and the stepped portion is At least partially covering the inner surface of the flange. The insulating filler is filled in the capacitor.

  According to the characteristic configuration described above, the stepped portion of the inner surface of the grounding metal fitting that is continuous with the first rising portion is at least partially covered by the stepped portion provided at the tip of the insulating cover. Insulating action by the stepped portion can be obtained corresponding to the covering mode and thickness by the attached portion. For this reason, at least the amount of covering by the stepped portion and the quantitative limit corresponding to the thickness reduce the filling amount of the insulating filler, relieve the stress accompanying the reduction of the resin filling amount, and improve the reliability. The cost can be reduced.

  Since the magnetron according to the present invention uses the above-described high-voltage feedthrough capacitor as a filter, the advantages of the high-voltage feedthrough capacitor according to the present invention are exhibited as they are.

  As described above, according to the present invention, the filling amount of the insulating filler is reduced, the stress associated with the reduction of the resin filling amount, the improvement of the reliability, and the cost reduction are achieved. And a magnetron can be provided.

  Other features of the present invention and the operational effects thereof will be described in more detail by way of examples with reference to the accompanying drawings.

  1 is a plan view showing an embodiment of a high-voltage feedthrough capacitor according to the present invention, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is a sectional view taken along line 3-3 of FIG. The illustrated high-voltage feedthrough capacitor includes a capacitor 1, feedthrough conductors 21 and 22, a grounding fitting 3, a first insulating filler 41, a second insulating filler 42, an insulating case 5, and an insulating case 5. A cover 6 and insulating tubes 71 and 72 are included.

The capacitor 1 includes a dielectric ceramic body 11, divided electrodes 12 and 13, and a common electrode 14. Two through holes 15 and 16 are provided in the dielectric ceramic body 11. The composition of the dielectric ceramic body 11 is arbitrary. For example, it is possible to a main component BaTiO ₃ -BaZrO ₃ -CaTiO _3, a composition comprising one or more additives. It is preferable that the dielectric ceramic body 11 has an appropriate R (roundness) as a whole in order to avoid concentration of mechanical and electrical stress.

  The two divided electrodes 12 and 13 are provided on one surface side of the dielectric ceramic body 11 so as to surround a region where the through holes 15 and 16 are opened. Each of the divided electrodes 12 and 13 is spaced apart by a recess 17. Although not shown, a convex portion may be used instead of the concave portion 17. Since the concave portion 17 is for increasing the creepage distance between the divided electrodes 12 and 13, the width and depth thereof are selected so that a necessary creepage distance can be secured. The common electrode 14 is provided on the other surface side of the dielectric ceramic body 11.

  The grounding metal 3 is made of, for example, a conductive metal material such as iron, copper, or brass, and has a raised portion 32 that rises on one surface side of the base portion 31. The floating portion 32 has a through hole 33 that penetrates from one surface side to the other surface side. The above-described capacitor 1 is mounted on the raised portion 32 of the ground metal fitting 3. The capacitor 1 is electrically connected to the surface of the raised portion 32 on the surface of the raised portion 32 by, for example, soldering. It is fixed mechanically.

  The through conductors 21 and 22 are two, and are made of a conductive metal material such as iron, copper, or brass, for example. The through conductors 21 and 22 pass through the through holes 15 and 16 of the capacitor 1 and further pass through the through hole 33 of the ground metal fitting 3.

  The through conductors 21 and 22 are electrically and mechanically connected to the divided electrodes 12 and 13 by electrode connecting bodies 23 and 24. The connection between the electrode connecting bodies 23 and 24 and the divided electrodes 12 and 13 is performed by means such as soldering.

  Of the through conductors 21 and 22, portions passing through the through holes 15 and 16 of the capacitor 1 and at least a portion passing through the through hole 33 of the ground metal fitting 3 are covered with insulating tubes 71 and 72. The insulating tubes 71 and 72 can be made of, for example, PET, PBT, silicone rubber, or the like.

  The insulating case 5 is provided on one surface side of the grounding metal 3, and one end is inserted into the outer peripheral side of the floating portion 32. The insulating cover 6 is provided on the other surface side of the grounding metal 3, and one end thereof is inserted into the inner peripheral side of the raised portion 32. The insulating case 5 and the insulating cover 6 can be made of, for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), modified melamine, or the like.

  The first insulating filler 41 is filled inside the insulating case 5 around the capacitor 1, and the second insulating filler 42 is filled inside the through holes 15 and 16 of the capacitor 1. . As the 1st insulating filler 41 and the 2nd insulating filler 42, thermosetting resins, such as a urethane resin and an epoxy resin, a phenol resin, a silicone resin, etc. can be used, for example.

  The structure described above is generally known in this type of high-voltage feedthrough capacitor. A feature of the present invention resides in the structure in which the insulating cover 6 is incorporated into the grounding metal 3 in the above-described high-voltage feedthrough capacitor. This point will be described in detail with reference to FIG. FIG. 4 is a partially enlarged sectional view of the high-voltage feedthrough capacitor shown in FIGS.

  In FIG. 4, first, the detailed structure of the grounding metal 3 will be described. The raised portion 32 of the grounding metal 3 has a recess 30 on the other surface side opposite to the surface on which the capacitor 1 is mounted. The inner surface of the concave portion 30 includes a first rising portion 34, a flange portion 35 that is connected to the first rising portion 34 and narrows the concave portion 30, and a second rising portion 36 that continuously rises from the flange portion 35. Yes.

  The first rising portion 34 forms a cylindrical body that rises substantially vertically from the base portion 31 that forms the outer peripheral edge. The flange portion 35 is continuous with the entire circumference of the cylindrical first rising portion 34 and is bent inside the recess 30. The second rising portion 36 rises continuously on the inner peripheral edge of the flange portion 35. Continuing at the tip of the second rising portion 36 is a second flange portion 37 that protrudes in the same direction as the flange portion 35. A through hole 33 is formed by the second flange portion 37. It can be said that this structure has a cross-sectional structure that gradually changes from the outside to the inside. Such a ground metal fitting 3 can be easily obtained by pressing a metal plate material.

  The capacitor 1 is mounted on the second flange portion 37 of the ground metal fitting 3, and the capacitor 1 has a portion of the common electrode 14 on the surface of the second flange portion 37, for example, means such as soldering. The connection is fixed electrically and mechanically.

  The above-described insulating cover 6 fitted into the recess 30 of the grounding metal 3 is cylindrical and has a stepped portion 61 at the end, with the stepped portion 61 at the tip, and the recess of the grounding metal 3. 30 is fitted to the inner surface. In this case, the stepped portion 61 partially covers at least the inner surface of the flange portion 35. In the illustrated embodiment, the stepped portion 61 provided at the end of the insulating cover 6 has a two-step configuration, and the first step surface 611 is in close contact with the lower surface of the flange portion 35, and the second step surface 612. Is in close contact with the inner surface of the second flange 37. Alternatively, they are brought into close contact via a resin. The rising surface between the first step surface 611 and the second step surface 612 is in close contact with the inner surface of the second rising portion 36, and further, the inner surface of the first rising portion 34 is covered with an insulating cover. The outer peripheral surface of 6 is in close contact. That is, the stepped portion 61 of the insulating cover 6 has a shape that follows the shape of the inner surface of the concave portion 30, and makes surface contact with the first rising portion 34, the flange portion 35, and the second rising portion 36. Alternatively, they are brought into close contact via a resin.

  The second insulating filler 42 filled in the through holes 15 and 16 of the capacitor 1 is formed on the second step surface 612 of the insulating cover 6 when viewed only in the fitting portion between the grounding fitting 3 and the insulating cover 6. Filled to touch.

  As described above, of the inner surface of the grounding metal 3, the flange portion 35 continuing to the first rising portion 34 is at least partially covered by the stepped portion 61 provided at the tip of the insulating cover 6. Insulating action by the stepped portion 61 is obtained in accordance with the covering mode and thickness by the stepped portion 61. For this reason, at least the aspect of covering by the stepped portion 61 and the quantitative limit corresponding to the thickness, while reducing the filling amount of the second insulating filler 42, improve the withstand voltage and reduce the cost. It becomes possible to plan. As a result, the stress accompanying the reduction in the filling amount of the resin constituting the second insulating filler 42 is alleviated and the reliability is improved.

  In the illustrated embodiment, the stepped portion 61 has a two-step configuration, the first step surface 611 is in close contact with the lower surface of the flange portion 35, and the second step surface 612 is the inner surface of the second flange portion 37. Therefore, a sufficient creepage distance is secured. In addition, the second insulating filler 42 filled in the through holes 15 and 16 of the capacitor 1 may be filled so as to be in contact with the second step surface 612 of the insulating cover 6, and the amount of use thereof is reduced.

  Next, another embodiment of the high-voltage feedthrough capacitor will be described with reference to FIGS. 5 to 7 are partially enlarged cross-sectional views of the high-voltage feedthrough capacitor according to the present invention. In these drawings, parts corresponding to the constituent parts appearing in FIGS. 1 to 4 are denoted by the same reference numerals.

  First, in the embodiment of FIG. 5, the stepped portion 61 of the insulating cover 6 is continuously in surface contact with the first rising portion 34 and the flange portion 35 of the ground metal fitting 3. The second insulating filler 42 is filled up to a position that coincides with the lower surface side of the stepped portion 61. Also in this embodiment, the bottom surface of the flange 35, which is the most problematic in terms of dielectric strength, is covered with the stepped portion 61, so basically the same as the embodiment shown in FIGS. A moderate effect can be obtained.

  Next, in the embodiment of FIG. 6, the stepped portion 61 of the insulating cover 6 is the same as that of the embodiment of FIG. 5 in that the stepped portion 61 of the ground cover 3 is in continuous surface contact with the first rising portion 34 and the flange portion 35. Although the same, unlike the embodiment of FIG. 5, the majority of the lower surface of the flange 35 is covered with a stepped portion 61. Even with such a structure, the same effects as those of the embodiment shown in FIGS.

  Further, in the embodiment shown in FIG. 7, the outer peripheral surface of the insulating cover 6 is separated from the inner surface of the first rising portion 34 of the grounding metal 3, but the stepped portion 61 is formed on the flange 35 of the grounding metal 3. In surface contact with the inner surface (lower surface in the figure). The second insulating filler 42 is filled up to a position that coincides with the lower surface side of the stepped portion 61. Also in this embodiment, the bottom surface of the flange 35, which is the most problematic in terms of dielectric strength, is covered with the stepped portion 61, so basically the same as the embodiment shown in FIGS. A moderate effect can be obtained.

  FIG. 8 is a partially broken sectional view showing an embodiment of the magnetron according to the present invention, and FIG. 9 is an electric circuit diagram of the magnetron shown in FIG. FIG. 8 shows a magnetron for a microwave oven, for example, and includes a filter box 84, a cathode stem 85, and a high-voltage feedthrough capacitor 9.

  The filter box 84 is disposed so as to cover the cathode stem 85 and is connected to the ground electrode GND (see FIG. 9). The filter box 84 includes a cooling fin 842, a gasket 843, an RF output end 844, and a magnet 845.

  The high-voltage feedthrough capacitor 9 is provided through a through hole provided in the side plate 841 of the filter box 84, and the grounding metal 3 is electrically and mechanically connected to the side plate 841.

  The inductors 81 and 82 are connected to the cathode terminal of the cathode stem 85 and the high-voltage feedthrough capacitor 9 inside the filter box 84.

  In FIG. 9, the high-voltage feedthrough capacitor 9 constitutes a filter together with inductors 81 and 82. Each of the inductors 81 and 82 has one end led to the oscillator 83 and the other end led to each of the divided electrodes 12 and 13.

In the magnetron, for example, a commercial voltage or a high voltage of about 4 kV _0-P having a frequency of about 20 kHz to 40 kHz is applied to the through conductors 21 and 22. As a result, the magnetron oscillates, but at this time, noise is generated. The generated noise is reduced by the filter action of the high voltage feedthrough capacitor.

  Although the contents of the present invention have been specifically described above with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. It is.

It is a top view which shows one Example of the capacitor | condenser which concerns on this invention. FIG. 2 is a sectional view taken along line 2-2 of FIG. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 1. FIG. 4 is a partially enlarged cross-sectional view of the high-voltage feedthrough capacitor shown in FIGS. 1 to 3. It is a partially expanded sectional view in another Example of the high-voltage feedthrough capacitor according to the present invention. It is a partially expanded sectional view in another Example of the high voltage feedthrough capacitor according to the present invention. It is a partially expanded sectional view in another Example of the high voltage feedthrough capacitor according to the present invention. It is a fragmentary broken sectional view which shows one Example of the magnetron based on this invention. It is an electric circuit diagram of the magnetron shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor 11 Dielectric porcelain body 12, 13 Divided electrode 14 Common electrode 3 Grounding fixture 30 Recessed part 32 Lifting part 34 First rising part 35 Gutter part 36 Second rising part 6 Insulating cover 61 Stepped end part

Claims (5)

A high-voltage feed-through capacitor including a grounding fitting, a capacitor, a through conductor, an insulating cover, and an insulating filler,
The grounding metal has a raised portion on one surface side, the raised portion has a concave portion on the inside, and the inner surface of the concave portion is connected to the first rising portion and the first rising portion, and the concave portion And a second rising part that rises continuously on the hook part,
The capacitor has two divided electrodes on one surface side, a common electrode on the other surface side, is mounted on one surface of the raised portion, and the common electrode is connected to the one surface of the raised portion. ,
The through conductors are two, each passing through the capacitor and the grounding fitting, and connected to the divided electrodes,
The insulating cover has a cylindrical shape, has a stepped portion at an end, is fitted to the inner surface of the concave portion of the ground metal fitting, with the stepped portion being a tip, and the stepped portion is , At least partially covering the inner surface of the buttocks,
The insulating filler is filled inside the capacitor;
High voltage feedthrough capacitor.   2. The high-voltage feedthrough capacitor according to claim 1, wherein the stepped portion of the insulating cover has a shape that follows a shape of an inner surface of the recess, and the first rising portion and the flange portion. And a high-voltage feedthrough capacitor in surface contact with the second rising portion.   2. The high voltage feedthrough capacitor according to claim 1, wherein the stepped portion of the insulating cover is continuously in surface contact with the first rising portion and the flange portion. 3.   2. The high-voltage feedthrough capacitor according to claim 1, wherein the insulating cover has a cylindrical portion excluding the stepped portion spaced apart from the first rising portion, and the stepped portion is formed on the flange portion. A high-voltage feed-through capacitor that makes surface contact. A magnetron including a high voltage feedthrough capacitor,
The high-voltage feedthrough capacitor is described in any one of claims 1 to 4, and is incorporated as a filter.
Magnetron.

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