JPH0738326B2 - Non-linear resistor manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a non-linear resistor having zinc oxide as a main component and having a high resistance layer on a side surface.

[Conventional technology]

FIG. 2 is a perspective view showing a conventional non-linear resistor disclosed in, for example, Japanese Patent Laid-Open No. 57-100702. In the figure,
(4) is a non-linear resistor, (5) is a side surface high resistance layer forming the periphery of the non-linear resistor (4), and (6) is an electrode.

The non-linear resistor (4) containing zinc oxide as a main component is widely used as a characteristic element such as a lightning arrester for protecting an electric device from an abnormal voltage due to a lightning strike in an electric system.

The side surface high resistance layer (5) is provided to prevent external flashover of the non-linear resistor (4) when a lightning impulse or the like strikes. That is, the situation where the resistor cannot withstand the attack of lightning impulse is basically whether the side surface has low withstand voltage and external flashover occurs, or the resistor is destroyed from the inside due to defects inside the resistor. Either, for example, X
When a defect such as an internal defect is removed by a line transmission photograph or the like, it is almost always due to the former external flashover. The side surface high resistance layer (5) is provided in order to make this external flashover less likely and to raise the threshold value for the lightning impulse.

The side surface high resistance layer (5) is formed by the following method. Antimony oxide, silicon oxide, and bismuth oxide are mixed at a predetermined ratio, and made into a paste with an appropriate organic binder and organic solvent (hereinafter referred to as an oxide paste). This oxide paste is applied to the side surface of a disc-shaped non-linear resistor molded body obtained by a general ceramics manufacturing method, or the calcined body obtained by calcining this molded body once at around 900 ° C. And then dried at about 100 ° C.

A molded body or calcinated body coated with this oxide paste
By firing at around 1200 ° C., the above oxide paste component reacts with the molded body component, and the side surface high resistance layer (5) is formed.

[Problems to be solved by the invention]

In the conventional method of forming the side surface high resistance layer, since the oxide paste is applied to the side surface of the cylindrical molded body or the like, considerable skill is required to apply the oxide paste uniformly and thickly.

Also, when particularly strict duty is required, it is recommended to increase the effective film thickness by preventing the reduction of the coating film thickness due to the dripping of the oxide paste by drying while rotating after applying the oxide paste. Needed a means.

The present invention has been made to solve the above problems, it is possible to easily produce a uniform coating film without requiring special skill, and without using a complicated device such as rotary drying. An object of the present invention is to obtain a method of manufacturing a non-linear resistor which can easily prevent a decrease in film thickness due to sagging of an oxide paste and can form a stable high resistance layer even under a severe duty.

[Means for solving problems]

The method for producing a non-linear resistor according to the present invention is a non-linear method for forming a coating film of an oxide paste containing at least one kind of metal oxide, an organic binder and an organic solvent on a side surface of a molded body. The original shape is maintained until the temperature of the molded body of the resistor element begins to shrink, and the side surface oxide paste is applied in advance to a tape woven with fibers of an inorganic substance that evaporates below the firing temperature of the molded body, and this tape is molded. This is to form a side surface high resistance layer on the side surface of the molded body by baking the obtained molded body after being attached to the side surface of the body or the like.

[Action]

In forming the coating film in the present invention, first, an oxide paste is applied onto a tape made of fibers of an inorganic substance. That is, this operation enables work at any place, for example, the Dr.Brade method of providing a uniform gap and applying it, for example, the uniform film thickness forming method such as the dipping method of immersing the tape in the paste can be adopted, It is possible to easily form a coating film of uniform thickness without requiring special skill.

The tape made of fibers of an inorganic substance used in the present invention is a tape-shaped tape made by weaving fibers made of an inorganic substance that keeps its original shape up to the temperature range where the organic solvent evaporates and evaporates at a temperature below the firing temperature of the molded body. Anything will do. For example, a glass fiber tape or the like.

The oxide paste penetrates between the fibers of the inorganic substance, and the fibers are in a form of holding the oxide paste. Since the fiber maintains its original shape at least up to the temperature at which the solvent evaporates, it prevents the sagging of the paste and contributes to the formation of a substantially thick and uniform side surface high resistance layer. Further, since the fibers evaporate at a temperature equal to or lower than the firing temperature of the molded body, the fibers themselves do not affect the characteristics of the nonlinear resistor.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 1 is a perspective view showing a situation in which a side surface paste layer is provided during a manufacturing process of a non-linear resistor according to the present invention, (1) is a molded body, (2) is an oxide paste layer, and (3) is an inorganic material fiber. It is a tape made.

First, zinc oxide and other types of additives are wet milled and mixed with an organic binder. 50 to 15 by spray drying
Granules of 0 μm were made, and the granules were made into a disc-shaped compact (1) having a diameter of 60 mm and a thickness of 30 mm by a molding machine.

Bismuth oxide (Bi ₂ O ₃ ), antimony oxide (Sb ₂ O ₃ ) and silicon oxide (SiO ₂ ) 20 mol%: 70 mol%: 10 mol%
2% ethyl cellulose was mixed with acetic acid n-
An oxide paste was prepared by dissolving it in butyl (evaporation temperature: 124 ° C.). This oxide paste is applied onto a tape (3) woven with inorganic material fibers, for example, a glass tape by a Dr. Brade method with a gear tape of 1 mm. The oxide paste applied on the glass tape penetrated between the glass fibers constituting the tape and was retained by the fibers. The amount of oxide paste applied was about 50 mg / cm ^{2 in} this example.

The tape (3) provided with the oxide paste layer (2) is cut into an appropriate size and wound around the molded body (1). The adhesive force at this time may use the viscosity of the oxide paste.

Even a beginner can easily perform the series of operations up to now, particularly the oxide paste application operation, and the application amount hardly varies.

The molded body (1) was fired at 1200 ° C., both end surfaces of the obtained sintered body were polished, and aluminum spray electrodes were provided on these end surfaces to obtain a non-linear resistor. When the impulse discharge withstand capability of this nonlinear resistor was investigated, it was 100KA (waveform:
External flashover did not occur even when an impulse of 4 × 10 μs) was applied. The other electric characteristics, such as VI characteristics and electric charge deterioration characteristics, were comparable to those of the conventional products.

Although the tape (3) was wound around the molded body (1) in the above example, the molded body (1) was preheated at 900 ° C to 1200 ° C.
It is calcined once and then shrunk to a certain degree.
It may be used instead of.

Further, as the tape (3) which is the essence of the present invention, the glass tape is used in the above embodiment, but the side surface paste layer (2) is used.
Keep its original shape up to the temperature range where the organic solvent of
Any tape-shaped one made by weaving fibers made of an inorganic substance that evaporates below the firing temperature of the molded body can be used.

Further, in the method of providing the side surface high resistance layer on the sheet, instead of applying the side surface paste on the tape, a so-called dipping method in which the tape is passed through the side surface paste may be used. If it is a manufacturing method using, the same effect as that of the above-mentioned embodiment can be obtained.

〔The invention's effect〕

As described above, according to the present invention, as a method of forming the side surface high resistance layer, the tape of the inorganic substance fiber provided in advance by the means such as coating the side surface paste is wound around the molded body. There is an effect that a uniform side surface high resistance layer can be easily obtained without the need for.

[Brief description of drawings]

FIG. 1 is a perspective view showing a situation in which a side surface paste layer is provided during a manufacturing process of a non-linear resistor according to an embodiment of the present invention.
FIG. 3 is a perspective view of a conventional non-linear resistor, and FIG. 3 is a side sectional view of the conventional non-linear resistor. In the figure, (1) is a molded body, (2) is a side paste layer,
(3) is a tape, (4) is a non-linear resistor, (5) is a lateral high resistance layer, and (6) is an electrode. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] 1. A tape made of fibers of an inorganic substance is coated with an oxide paste containing at least one kind of metal oxide, an organic binder and an organic solvent, and the tape is attached to the side surface of the element of the non-linear resistor. A method for producing a non-linear resistor, characterized by forming a lateral high resistance layer on a side surface of the device by firing the obtained device. 2. A method for producing a non-linear resistor according to claim 1, wherein the inorganic substance maintains its original shape at least up to a temperature at which the organic solvent evaporates, and evaporates at a temperature equal to or lower than the firing temperature of the device. Method. 3. The method for producing a non-linear resistor according to claim 2, wherein the inorganic substance is glass fiber.