JP3641706B2 - Ceramic resistor for high voltage - Google Patents

Description

【０００８】
【表２】

【０００９】
【発明の効果】
実施例の比較データからも明らかなように、本発明のセラミック質抵抗体は、高電圧大電流パルスに強く、電気的接触も安定した高電圧用セラミック質抵抗体を供給することができ、特に高電圧回路で大電流パルスが頻繁に印加される用途の抵抗体の分野で非常に有効と言える。
【図面の簡単な説明】
【図１】本発明の高電圧用セラミック質抵抗体の断面図。
【図２】金属端子を抵抗素体端部の外円周側面部にかぶせ電極とした従来の高電圧用セラミック質抵抗体の断面図。
【図３】金属端子を抵抗素体端部の断面部に接着して電極とした従来の高電圧用セラミック質抵抗体の断面図。
【符号の説明】
１．抵抗素体
２．絶縁性塗膜
３．絶縁性接着材
４．キャップ
５．金属端子
６．ばね
７．接触補助端子
８．電極
９．半田
１０．外部接続端子取付孔[0001]
[Industrial application fields]
INDUSTRIAL APPLICABILITY The present invention is used in an application in which a large current pulse is frequently applied to a resistor in a region having a relatively low resistance value in a high voltage circuit. More specifically, the present invention relates to a ceramic resistor used for applications such as a braking resistor, a discharge resistor, a UHV test transformer protective resistor of an impact voltage generator.
[0002]
[Prior art]
Conventionally, a ceramic resistor used for a high-voltage circuit is formed in an electrode on the circumferential side surface at the end of either a rod-shaped or cylindrical shape, and a metal terminal is covered so as to cover the electrode, Electrical contact and mechanical holding are performed by solder, conductive adhesive, springs, and the like.
Another type is a structure in which an electrode is formed only at the cross section of the end of either a rod or cylinder, and the metal terminal is in contact with only the cross section. There is a resistor (Japanese Patent Publication No. 3-42481) in which a small portion of the outer circumference of the element body is filled with an insulating adhesive for reinforcement.
[0003]
[Problems to be solved by the invention]
In the conventional type in which electrodes are formed on the outer circumferential side of the end of the ceramic resistor, corona occurs when a large current pulse is applied at a high voltage and a low resistance value.
In the conventional type in which the electrode is formed only at the cross section at the end of the ceramic resistor, no corona occurs, but peeling occurs at the boundary between the resistor element and the metal terminal due to frequent application of a large current pulse. There was a disadvantage that electrical contact was lost.
[0004]
The present invention makes use of the advantages of the two types of high-voltage ceramic resistors according to the prior art and compensates for their respective disadvantages, so that no corona occurs even when a large current pulse is frequently applied. In addition, the metal terminal is not separated from the resistor element body, and the electrical contact is not lost. In the present invention, in the prior art, the metal terminal has two functions of an electrode and a function of fixing the resistor element. By providing a cap separately, the cap is connected to the resistor element. It is limited to the function of fixing only, and the function of the electrode is given to another metal terminal. The resistor element is rod-shaped or cylindrical, and an insulating coating film having a thickness of 20 to 500 microns, preferably an epoxy resin coating film, is formed on the outer peripheral side surface, and electrodes are formed on both end surfaces. The cap may be made of any material such as metal, plastic or ceramic, preferably made of metal with little thermal deformation, especially brass, aluminum and ceramic with good workability, and its shape is a hollow cylindrical shape than the outer diameter of the resistor element. has a degree 2~10mm large inner diameter, and the end of the resistor element body to the vicinity of the center of the cap, preferably by insertion 5 to 20 mm, the resistance element and the inner peripheral surface of the cap in the resistance element insertion portion of the cap Insulating adhesive is filled in the gaps on the outer peripheral surface of the substrate. The material of the insulating adhesive to be filled is the same material as the insulating coating film of the resistor element, preferably an epoxy resin, so that the resistor element and the adhesive are not separated. Further, a groove having a depth of 0.5 mm or more and a width of 2 mm or more is provided on the inner peripheral surface of the cap in the resistance element insertion portion of the cap, and the cap and the resistor element are formed on the inner peripheral surface of the cap. It is fixed with an adhesive through the groove or unevenness. The total length of the cap is preferably 10 to 40 mm, and is divided into a portion where the resistor element is inserted and a portion where the metal terminal is inserted . The inner peripheral surface of the cap into which the metal terminal is inserted is threaded, and the metal terminal is fitted to the cap with a screw. A spring is inserted between the metal terminal and the electrodes formed on both end faces of the resistor element, and the electrode of the resistor element is pressed by the metal terminal via the spring, so that the electrical contact between the metal terminal and the electrode is Retained. The metal terminal is preferably manufactured from aluminum, copper, brass, nickel, or iron. In particular, it is preferably made of a metal member in which corrosion is reduced by applying nickel plating to aluminum, copper, and brass that are good electrical conductors.
[0005]
[Action]
The present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the present invention, and FIGS. 2 and 3 are conventional sectional views.
In FIG. 1, the resistor element 1 and the cap 4 are fixed by an insulating adhesive 3, and the adhesive is a material similar to the insulating coating 2 of the resistor element 1, preferably an epoxy resin. Even if the cap 4 and the insulating adhesive 3 lose their adhesive force due to the difference in material, they will not come off due to the uneven shape of the bonding surface between the cap 4 and the adhesive 3. Further, the electrical contact is made by the metal terminal 5 and the spring 6, preferably a disc spring, the contact auxiliary terminal 7 and the electrode 8 in the cross section, and is kept independent of the cap 4.
The metal terminal 5 and the cap 4 are respectively subjected to male and female screw processing of the same standard, and the screw can be pressed against the electrode 8 in the cross section of the resistor element 1. Moreover, since it is the press-contact through the spring 6, even if looseness arises by the difference in the expansion coefficient by the difference in a material, a contact can be maintained and an electrical contact can be hold | maintained.
[0006]
【Example】
Hereinafter, a comparative example of a withstand voltage test of a resistor manufactured by the present invention and a conventional method will be shown.
In order to eliminate the preferential difference of resistance element bodies, samples for comparison experiments were manufactured by using resistance element bodies having the same dimensions and the same resistance value. The configuration is shown in Table 1.
As test conditions, an application is started from a peak voltage of 80 KV with a waveform of 5 × 15 μs by an impact voltage generator, and the voltage is increased by 20 KV. After 5 times of continuous application under one condition and sufficient cooling by air cooling, the process proceeds to the next condition. The results are shown in Table 2.
[0007]
[Table 1]

[0008]
[Table 2]

[0009]
【The invention's effect】
As is clear from the comparative data of the examples, the ceramic resistor of the present invention can provide a high-voltage ceramic resistor that is resistant to high-voltage, large-current pulses and stable in electrical contact, This can be said to be very effective in the field of resistors for applications where high current pulses are frequently applied in high voltage circuits.
[Brief description of the drawings]
FIG. 1 is a sectional view of a ceramic resistor for high voltage of the present invention.
FIG. 2 is a cross-sectional view of a conventional high-voltage ceramic resistor in which a metal terminal is used as an electrode covering the outer circumferential side surface of the resistor element end.
FIG. 3 is a cross-sectional view of a conventional high-voltage ceramic resistor used as an electrode by bonding a metal terminal to a cross-sectional portion at the end of a resistor element.
[Explanation of symbols]
1. 1. Resistive element body 2. Insulating coating film Insulating adhesive 4. Cap 5. Metal terminal 6. Spring 7. Contact auxiliary terminal 8. Electrode 9. Solder 10. External connection terminal mounting hole

Claims (1)

In the ceramic membrane resistor applications where high voltage is applied, the outer peripheral surface in the rod-shaped or cylindrical electrodes are formed on both end faces of the resistor element body insulating coating film is formed, the ends of the resistor element Is inserted into a hollow cylindrical cap, and a groove or an unevenness is provided on the inner peripheral surface of the cap in the resistance element insertion portion of the cap, and the inner peripheral surface of the cap and the resistance element body in the resistance element insertion portion of the cap An insulating adhesive of the same material as that of the insulating coating film is filled between the outer peripheral surface of the cap and the end of the cap and the resistor element body through grooves or irregularities formed on the inner peripheral surface of the cap. The metal terminal is fitted to the cap with a screw, a spring is inserted between the metal terminal and the electrode of the resistor element, and the electrode of the resistor element is spring-loaded by the metal terminal. Between the metal terminal and the electrode. Ceramic membrane resistor for high voltage erosion is characterized in that it is held.

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