JPH0574922B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a non-linear resistor, and more particularly to a method for manufacturing a non-linear resistor with an improved electrode attachment process.

[Technical background of the invention and its problems]

In electrical systems, overvoltage protection devices are used to protect the electrical system by removing overvoltages superimposed on normal voltages.

This overvoltage protection device uses a nonlinear resistor that exhibits substantially insulating properties at normal voltage and becomes relatively resistant when overvoltage is applied.

Nonlinear hypoantibodies can be made by mixing zinc oxide (ZnO) with metal oxides and firing the molded material.

ZnO-based nonlinear resistors have steep nonlinear characteristics in the small current range and have a sharp rise up to the large current range, so they are better than overvoltage protection devices using SiC-based nonlinear resistors. It can make an excellent overvoltage protection device.

However, ZnO-based non-linear resistors require many manufacturing processes and are difficult to mass-produce industrially, resulting in a decrease in non-linear resistance characteristics and large variations in their characteristics, such as charge life and discharge withstand capacity. There is a problem that other performance deterioration also occurs.

For example, generally, a high-resistance layer is applied to the side surfaces of a disc-shaped sintered body and baked, and then both surfaces are polished and electrodes are applied to these surfaces. This electrode formation process is performed as follows. It is done. That is, as shown in FIG. 4, symmetrical half-split jigs 1a and 1b made of elastic resin and formed into a substantially cylindrical shape are used, and these jigs are placed between both flat surfaces of the sintered body 3. The non-linear resistor is completed by covering it from the side shown in the figure and forming the electrode 2 by metallizing it with aluminum, for example. However, when using these jigs 1a and 1b, the adhesion to the side surface of the sintered body is not good, so the electrode material adheres to the circumferential part and the side surface of both planes, and the metallicon size is 0.1 to 0.1 The standard for providing a 1.5mm margin could not be met. This shows the flanges 1a1 and 1a1 of jigs 1a and 1b when the contact surfaces of jigs 1a and 1b are in contact with each other.
This is due to the mismatch between the distance between the facing surfaces of 1b1 and the thickness of the sintered body 3.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a method for manufacturing a non-linear resistor in which variation in characteristics and deterioration in performance are improved.

[Summary of the Invention] In order to achieve the above object, the present invention provides a method for manufacturing a non-linear resistor in which electrodes are provided on a sintered body containing zinc oxide as a main component. The electrode is applied using a jig made of elastic resin with a shaped structure.

[Embodiments of the invention]

Hereinafter, the present invention will be explained based on examples. Bismuth oxide (Bi ₂ O ₃ ), antimony oxide (Sb ₂ O ₃ ), chromium oxide (Cr ₂ O ₃ ), cobalt oxide (CoO), and manganese oxide (MnO) are added to the main component, zinc oxide (ZnO) powder. etc. powder respectively 0.01~6.0
Add in a mol% range and mix with a ball mill.
At this time, the oxide and an organic binder such as polyvinyl alcohol are mixed simultaneously. The mixture thus obtained is placed in a dry granulation device, for example a spray dryer, to form spherical agglomerates. This powder mixture is pressed to a thickness of, for example, 100 mm in diameter and 25 mm in thickness.
Form into a mm disk.

This molded product is fired and sintered in an electric furnace. The firing temperature is 1300°C and the appropriate time is 6 hours.

The disc-shaped fired product after firing shrinks more than before firing, but has a substantially homogeneous composition and density. A high-resistance layer is applied to the side surfaces of this fired product, baked, and both surfaces are polished. Next, as shown in FIG. 1, a jig 4 made of elastic resin and having an asymmetrical structure is attached.
By covering the sintered body 5 with a and 4b, the electrode material is prevented from adhering to the circumferential surface and side surfaces.

That is, the jigs 4a and 4b have side portions 4a1,
4b1 has a structure in which the tips thereof have sloped surfaces in opposite directions, so that when both jigs 4a and 4b are butted against each other, the sloped surfaces coincide with each other.
The jig 4a is inclined in such a direction that the inner surface is long and the outer surface is short, and the jig 4b is inclined in such a direction that the inner surface is short and the outer surface is long, contrary to the jig 4a. Therefore, when the jigs 4a and 4b are placed over the sintered body 5, the jigs 4a and 4b are placed over the sintered body 5 because of the inclined surfaces.
The inner surfaces of the flanges 4a2 and 4b2 of the flange 4b are in good contact with the plane of the sintered body 5. With the planar circumferential portion and side surface of the sintered body 5 in close contact with each other using a jig, the electrode 6 is formed on the planar surface using aluminum metallicon.

The degree of variation in the nonlinear hypoantibodies produced in this manner is shown in FIGS. 2 and 3.

Figure 2 shows the variation in V _1nA for a nonlinear resistor designed with V _1nA as 4000V. The horizontal axis shows V _1nA , and the vertical axis shows the amount generated when the manufacturing equipment is taken as 100%, as a relative value. Curve A shows the degree of effect achieved by the manufacturing method of the present invention, that is, by the jig made of elastic resin having an asymmetric structure. Curve B shows an example of a non-linear resistor in which electrodes are attached using a conventional symmetrical half-shaped jig.

As is clear from FIG. 2, it was confirmed that the designed V _1nA of the nonlinear resistor manufactured by the manufacturing method of the present invention was concentrated around 4000V, and the variation in electrical characteristics was small.

FIG. 3 shows variations in the margins of metallization on the surface of a nonlinear resistor. The horizontal axis shows the dimensions of the metallic contact margin, and the vertical axis shows the generated quantity as a relative value when the manufacturing quantity is set as 100%. Curve A shows an example of a non-linear resistor according to the present invention, and curve B shows an example of a non-linear resistor manufactured using a conventional symmetrical half-shaped jig.

As is clear from FIG. 3, the non-linear resistor according to the present invention had small variations in the dimensions of the metallic contact margin and was able to satisfy the standards.

As mentioned above, when performing metallization, the sintered body is covered with a pair of jigs made of elastic resin that have an asymmetrical structure with sloped parts in opposite directions on the abutting surfaces. , it is possible to make the margins of the metallic contact uniform, and the discharge withstand characteristics are better than those manufactured using a conventional symmetrical half-piece jig because there is no electrode material adhering to the sides, which reduces damage such as side flashing. It is possible to obtain a higher quality non-linear resistor.

〔Effect of the invention〕

As described above, according to the present invention, a pair of elastic resin materials having an asymmetrical structure with sloped portions in opposite directions on the abutting surfaces of the sintered resin material mainly composed of zinc oxide are provided. By attaching electrodes using a tool, it is possible to provide a nonlinear resistor with improved characteristics variation and performance deterioration.

[Brief explanation of the drawing]

FIG. 1 is a side view showing one embodiment of the non-linear resistor of the present invention, FIGS. 2 and 3 are curve diagrams explaining the electrical characteristics and quality characteristics of the non-linear resistor of the present invention, and FIG. FIG. 2 is a side view showing an example of a conventional linear hypoantibody. 4a, 4b... jig, 4a1, 4b1... side part, 4a2, 4b2... flange, 5... sintered body, 6... electrode.

Claims (1)

[Claims] 1. In a non-linear resistor made by mixing an oxide with zinc oxide and firing it, when polishing both planes of the sintered body and providing electrodes, the mutual contact that covers the plane circumference and side surfaces of the sintered body is removed. A method for manufacturing a nonlinear resistor, characterized in that electrodes are attached using a jig made of elastic resin and having an asymmetrical structure in which the mating surface is an inclined surface.