JPH0645324U - High voltage ceramic capacitors - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To provide a high-voltage ceramic capacitor that is not electrically damaged even when a large impulse voltage is applied. [Structure] A barrel having a bulging central portion of a connecting conductor of a high-voltage ceramic capacitor in which a plurality of ceramic capacitors are formed by connecting electrodes on two opposite surfaces of a ceramic dielectric, using connecting conductors in series. Formed in the shape of a mold, or formed so that the connecting conductor has an inclined end portion that is separated from the ceramic capacitor, or the central portion of the surface of the ceramic dielectric on the side of the connecting conductor is bulged with respect to the peripheral portion. .

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a high voltage ceramic capacitor.

[0002]

[Prior art]

 High-voltage capacitors have been used for voltage distribution in high-voltage circuit breakers, power sources for laser oscillators, power sources for electrostatic precipitators, etc. Conventionally, plastic film capacitors or oil-impregnated paper capacitors have been used as such capacitors.

In place of the plastic film or oil-impregnated paper, which is the dielectric material used in conventional plastic film capacitors or paper capacitors in order to miniaturize such capacitors, it is a material with a high relative dielectric constant. , BaTiO ₃ (barium titanate) or SrTiO ₃ (strontium titanate) is used as a ceramic capacitor.

In this high-voltage ceramic capacitor, it has been proposed to mold the entire high-voltage ceramic capacitor with resin in order to protect the ceramic such as BaTiO ₃ or SrTiO ₃ which is a dielectric. Fig. 4 shows an example of a conventional high-voltage ceramic capacitor molded with a different resin. The conventional high-voltage ceramic capacitor shown in FIG. 4 (b) is an enlarged sectional view of part (a) in FIG. 4 (a). Are connected in series, and electrodes 23 and 24 made of silver or the like are provided on both sides of a dielectric body 21 made of ceramic such as BaTiO ₃ or SrTiO _{3 and} electrodes made of silver or the like are also placed on both sides of the dielectric body 22. 25 and 26 are provided, a cylindrical connecting conductor 28 made of brass is attached to the electrodes 24 and 25 by soldering, and external lead-out terminals 27 and 29 made of brass are attached to the electrodes 23 and 26. , And the entire part except the external lead-out terminals 27, 29 is molded with resin 30.

[0005]

[Problems of conventional technology]

 In this high-voltage ceramic capacitor, thermal stress generated when the connecting conductor 28 and the external lead terminals 27 and 29 are soldered, in particular, the stress of pulling the ceramic inward by the solder, and when the resin is polymerized and solidified. A large stress is applied to the entire high voltage capacitor due to the contraction force generated in the capacitor.

When a large impulse voltage is applied to the high-voltage ceramic capacitor in such a state, the external lead-out terminal 27 is soldered to the electrode 23 and the connecting terminal 28 is soldered to the electrode 24, and between the electrodes 24. A large compressive force is applied between the electrode 25 to which the connection terminal 28 is soldered and the electrode 26 to which the external lead terminal 29 is soldered, and a repulsive force is applied between the opposing electrodes 24 and 25. When these forces are combined with the above-mentioned stress, a crack is generated in the soldering portion 31 between the electrode 24 and the connecting conductor 28 and the soldering portion 32 between the connecting conductor 28 and the electrode 25, and this crack is generated. If it gets larger, the high-voltage ceramic capacitor may eventually be electrically destroyed.

[0007]

[Problems to be solved by the device]

 The present invention reduces the thermal stress generated when soldering the connecting conductor and the external lead terminal among the forces applied to the high-voltage ceramic capacitor, so that a large impulse voltage is applied to the high-voltage ceramic capacitor. However, it is an object of the present invention to provide a high-voltage ceramic capacitor in which a soldering portion between an electrode and a connecting conductor and a soldering portion between a connecting conductor and an electrode are not cracked and electrically broken.

[0008]

[Means for Solving the Problems]

 In order to achieve the above object, in the present application, "in a high-voltage ceramic capacitor in which a plurality of ceramic capacitors each having electrodes provided on two opposing surfaces of a ceramic dielectric are connected in series using a connecting conductor, The device is a high-voltage ceramic capacitor characterized in that the conductor is in the shape of a barrel with a bulge in the central part. "The electrodes are provided on two opposite surfaces of the ceramic dielectric. A high-voltage ceramic capacitor in which a plurality of formed ceramic capacitors are connected in series using a connecting conductor, wherein the connecting conductor has an inclined end portion that is separated from the ceramic capacitor. And a ceramic having two electrodes facing each other on the ceramic dielectric. High-voltage ceramic capacitor, in which a plurality of connection capacitors are connected in series by using connection conductors, the central part of the surface of the ceramic dielectric on the connection conductor side is bulged with respect to the peripheral part. A device configured to be a "capacitor" is provided.

[0009]

[Action]

 In the high-voltage ceramic capacitor according to the present invention having the above-mentioned configuration, the stress that attracts the ceramics inward by the terminals is reduced by soldering, so that a large stress is applied to the entire high-voltage ceramic capacitor. The electrical destruction of the is prevented.

[0010]

【Example】

The present invention will be described with reference to FIGS. A first embodiment of the high voltage ceramic capacitor according to the present invention is shown in FIG. 1, and a second embodiment is shown in FIG. Similar to the conventional example shown in FIG. 4, (b) is an overall cross-sectional view, and (a) is an enlarged view of a portion in (b), showing the height of the first and second embodiments of the present invention. Similarly, the voltage ceramic capacitor is composed of two ceramic capacitors connected in series in order to increase the withstand voltage, and the silver is formed on both sides of the dielectric 1 made of ceramic such as BaTiO ₃ or SrTiO _3. The electrodes 3 and 4 made of silver or the like are provided on both surfaces of the dielectric 2, and the electrodes 5 and 6 made of silver or the like are also provided on the both surfaces. The connecting conductor 8 made of brass is attached to the electrodes 4 and 5 by soldering. External lead-out terminals 7 and 9 made of brass are attached to the electrodes 3 and 6 by soldering, and the entire part except the external lead-out terminals 7 and 9 is molded with a resin 10.

In the first embodiment, unlike the conventional example shown in FIG. 4, the shape of the connecting conductor 8 is not a cylindrical shape but a barrel shape having a bulged portion 11 in the central portion.

Since the basic configuration of the second embodiment shown in FIG. 2 is common to that of the high voltage ceramic capacitor of the first embodiment shown in FIG. 1, only the non-common parts will be described here. The connecting conductor 8 of the high voltage ceramic capacitor of the second embodiment has slanted ends 12 and 13 which are separated from the dielectric ceramic. The angle formed by the slanted end and the dielectric ceramic is preferably 15 ° to 30 °.

FIG. 3 shows an enlarged view of a portion where two ceramic capacitors are connected in series by using connecting conductors in the third embodiment. The high-voltage ceramic capacitor shown in this embodiment is different from the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. 2 in that the connecting conductor 18 has a simple tubular shape, but is made of ceramic. The central portions of the surfaces of the dielectrics 14 and 15 on the side of the connection conductors bulge out toward the peripheral edge portions, whereby the space between the ceramic dielectrics 14 and the connection conductors 18 and the connection conductors 18 and 15 are A void is formed between the solder layers 19 and 20, and the solder layers 19 and 20 are present only in the center of the void. The bulge amount in this case is about 0.1 mm.

[0014]

[Effect of device]

 In the high voltage ceramic capacitors according to the present invention described in the first to third embodiments, the area of the solder layer connecting the ceramic dielectric and the connecting conductor is smaller than that of the conventional one. Therefore, in the high-voltage ceramic capacitor according to the present invention, the stress that pulls the ceramic inward by the terminals is reduced by soldering, and the electrical breakdown of the high-voltage ceramic capacitor due to the large stress can be reduced. .

With respect to this point, the results of an impulse withstand voltage test performed by applying an impulse voltage having a peak voltage of 80 KV and a pulse width of 1.2 × 50 μs once are listed below. The samples are those of the first embodiment, those of the second embodiment in which the connecting conductor is inclined at 90 °, 45 °, 30 °, and 15 ° at the inclined end portions spaced from the ceramic capacitor, and the third embodiment. An example was tested. As a result, the defective product rate of the first embodiment is 0%, the defective product ratio of the second embodiment is 90%, the defective product ratio is 8.0%, and the defective product ratio of the second embodiment is 45%. The non-defective product rate is 5.2%, the defective product ratio of the second embodiment having an inclination of 30 ° is 0.5%, and the defective product ratio of the second embodiment having an inclination of 15 ° is 0%, the third. The defective rate of the example was 0.5%.

[Brief description of drawings]

FIG. 1 is a partial sectional view and an overall sectional view of a first embodiment of the present invention.

FIG. 2 is a partial sectional view and an overall sectional view of a second embodiment of the present invention.

FIG. 3 is a partially enlarged sectional view of a third embodiment of the present invention.

FIG. 4 is a partial sectional view and an overall sectional view of a conventional example.

[Explanation of symbols]

 1,2,14,15,21,22 Dielectric 2,4,5,6,23,24,25,26 Electrode 8,18,28 Connection conductor 7,9,27,29 External lead-out terminal 10,30 Resin 11 Bulging part 12, 13 Inclined end part 19, 20 Solder layer 31, 32 Soldering part

Claims (3)

[Scope of utility model registration request] 1. A high-voltage ceramic capacitor in which a plurality of ceramic capacitors each having electrodes provided on two opposite surfaces of a ceramic dielectric are connected in series by using a connecting conductor, wherein the connecting conductor has a swelled central portion. A high-voltage ceramic capacitor, which is characterized by the barrel shape that is put out. 2. A high-voltage ceramic capacitor in which a plurality of ceramic capacitors each having electrodes provided on two opposing surfaces of a ceramic dielectric are connected in series by using a connecting conductor, wherein the connecting conductor is the ceramic capacitor. A high-voltage ceramic capacitor having slanted ends spaced apart from each other. 3. A high-voltage ceramic capacitor in which a plurality of ceramic capacitors each having electrodes provided on two opposite surfaces of a ceramic dielectric are connected in series using a connection conductor, wherein the connection conductor of the ceramic dielectric is A high-voltage ceramic capacitor, characterized in that the central part of the side surface is bulged with respect to the peripheral part.