JPS6028365B2 - Manufacturing method of voltage nonlinear resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method for manufacturing an electric nonlinear resistor whose main component is zinc oxide (Zn0).

B. In the method of manufacturing a voltage nonlinear resistor of the invention, in which an insulating film is formed on an element body having a rounded chamfer on the peripheral edge of the element body or a groove with a rounded edge on the edge, traditional This method attempts to easily form an insulating film of uniform thickness by forming the insulating film through a gas phase-solid phase reaction through firing and evaporation or sublimation of the insulating film forming material.

C. PRIOR TECHNOLOGY Conventionally, a voltage non-linear resistor used in a lightning shielding element, etc. has a cylindrical body 1 with a length D and a thickness t, as shown in FIG.
An insulating film 2 for preventing creeping discharge is formed on the circumferential surface of the element body 1, and electrodes 3 and 4 are formed on both end surfaces of the element body 1.

To form an insulating film on a voltage nonlinear resistor having such a configuration, an organic insulator such as epoxy resin or an inorganic insulator such as aluminum phosphate or soluble silicate is applied after firing the element.

Alternatively, a low melting point glass or an inorganic thermosetting insulating film forming material is applied after firing the element, and heated at a temperature lower than the firing temperature of the element so as not to adversely affect various properties of the element. Alternatively, a glassy or crystalline insulating film-forming material is applied to the press-formed product before firing the element, and the film is also formed at the same time as the firing of the element. Alternatively, there is a method of temporarily lighting the element, applying a film-forming material, and forming an insulating film at the same time as the main firing of the element. D Problems to be Solved by the Invention However, even with the above-mentioned and offset methods, it is necessary to apply the insulating coating material, and it takes considerable skill to apply it uniformly to the rounded part of the twill part of the body. In addition, special jigs and equipment are required to improve mass production in order to apply the coating to a uniform thickness on areas other than the twill, and even if these jigs are used, it is not possible to achieve a uniform thickness. It was difficult.

The manufacturing method of the present invention solves all of the above-mentioned problems, and is a method for forming an insulating film extremely easily and uniformly on the side surface of an element having a complex shape, including rounded edges.

E. Means for Solving the Problem The voltage nonlinear resistor to which the first invention is directed has an element body 5 as shown in FIG. 2a.
The edge 5A has an R chamfer, and an insulating film 6 is formed on the circumferential surface of the body including this edge 5A.

This R-chamfering of the green part of the mill body and the formation of an insulating film are performed not only on the outer circumferential surface twilling part 7A but also on the inner circumferential surface green part 7B of the hollow millet 7, as shown in FIG. 2b. Insulating films 8A and 8B are formed on the inner peripheral surface. These R chamfers are made to have a maximum of t/2. In this way, the structure in which the rounded edge is rounded and an insulating film is also formed on this rounded side reduces the concentration of electric field at the periphery compared to the one shown in Fig. 1, and the green part Partial discharge is suppressed, and chipping of the circumferential twill portion can also be prevented.

In the first invention, in the structure as described above, in order to form an insulating film on the circumferential surface of the body including the R-chamfered part, the element body is compression-molded or re-molded on a heat-resistant pedestal in the firing sac. The insulating film forming material is placed in the vicinity of this sinter body, and the firing shard is covered with a lid made of the same material as the firing shard and heated to cause firing of the element and evaporation or sublimation of the insulating film forming material. An insulating film is formed on the surface of the element body through a gas phase-solid phase reaction on the surface of the element body.

In addition to the chamfering of the circumferential twill portion R of the first invention, the voltage non-linear resistor to which the second invention is directed has the circumferential surface of the square body 9 as shown in a half cross section in FIG. 3 a or b. A resistor having a structure in which at least one groove 9A is formed in the circumferential direction by R-chamfering, that is, a structure in which the circumferential surface is uneven, and an insulating film 10 is formed along the circumferential surface including the uneven portions. It has a body structure.

FIG. 3a shows a case with two square grooves, and FIG. 3b shows a case with four wavy grooves. In this way, R
The structure having a chamfered groove and an insulating film formed on the circumferential surface increases the creepage distance, thereby reducing circumferential leakage current and suppressing creeping discharge.

Furthermore, the surface area of the element body exposed to the atmosphere increases, the heat dissipation effect from the element body improves, and an increase in current due to temperature can be suppressed. For example, the structure shown in FIG.
Compared to a conventional structure that does not have this structure, the creepage distance and peripheral surface area are improved to the values shown in the table below. However, the one of the present invention has a diameter of 3
This is a case where the element body on the 25-thickness side has two grooves of 5 depth and 5 width at equal intervals. Note that the formation of grooves is not limited to the circumferential surface of the element body, as shown in FIG. Similar effects can be obtained by forming the insulating film 12. Furthermore, a voltage nonlinear resistor that has R-chamfered grooves formed on both the end surface and the circumferential surface of the element body is also an opposing voltage nonlinear resistor of the present invention. In the second invention, in addition to the R-chamfered structure of the first invention, the target voltage non-linear resistor has a groove in which the green groove is R-chamfered in the direction between the surfaces of the element body excluding the electrode forming surface. , and an insulating film is formed on the inter-element surfaces and grooves including each R chamfered portion, and the method of forming the insulating film, which is the main part, is the same as that of the first invention.

F action In both the first invention and the second invention, when the insulating film is heated above a certain temperature, the insulating film forming material of the high vapor pressure component evaporates or sublimates, reaching the surface of the element body, and the Zn○ and gas in the element body are heated. It is formed into a uniform thickness by a phase reaction.

G. Example Hereinafter, the first invention will be explained in detail based on an example shown in FIG.

Note that the second invention differs only in the configuration of the target voltage nonlinear resistor, so a description thereof will be omitted.
As shown in FIG. 5, a hollow compression-molded or calcined blank 13 is placed into an alumina sac 15 via a heat-resistant ceramic pedestal 14, and a mask material 1 made of the same material as the pedestal 14 is placed.
Put 6 on it.

For example, an auxiliary member 17 made of the same material as the shell 15 is installed in the hollow portion. On the inner surface of the shell 15 and the outer surface of the auxiliary part 17, a forming material 18 which forms a peripheral insulating film by a gas-solid reaction with the Znq element at high vapor pressure is applied to an appropriate area and an appropriate thickness. A sufficient amount is applied to form a side insulation film with a thickness of 10A or more. Incidentally, since the insulating film is formed by a gas phase-solid phase reaction, the insulating film material may be placed near the body. Place the lid 19 made of the same material as the pod so that there is almost no gap between the pod and the pod, and
When heated above qo, the insulating coating material 18, which is a high vapor pressure component, evaporates or sublimates and reaches the surface of the element, whereupon the Zn○ in the millet and the gas phase -
A peripheral insulating film with high electrical properties is formed by solid-phase reaction, and the firing of the device is completed at the same time. The base 15 and the mask material 16 are best made of a zinc oxide-based solidified plate since it does not have a negative effect on the properties of the material, and powder may also be used.

If the sheath 15 is large and the distance from the body 13 is large, an auxiliary member such as a cylinder may be provided between the inner surface of the sheath and the element body 20, and an insulating coating material may be applied to the inner surface of the auxiliary member. As the peripheral insulating film material 18, Zn23Sbo. Suitable materials include antimony oxide, silica, which forms Nail 04 and Znbu i04, and bismuth oxide, which accelerates the reaction.

Silica has a low vapor pressure, but sublimation of SQ03 or Bi203
It is thought that it reaches the Qin body surface as it evaporates and reacts with the element body. The mask material 16 is not necessarily required. That is, when providing electrodes on the element body after firing, the surface is polished, so for example,
Since it takes only a short time to polish the 0-mountain surface, the price of the surface does not increase. On the other hand, in the second invention, the third invention
A uniform insulating film can also be formed on the groove portion and the R surface portion of the element body provided with the grooves shown in FIGS.

H. Effects of the Invention As described above, according to the first and second inventions, the insulating film of the voltage nonlinear resistor is formed by a gas-phase reaction that is carried out at the same time as the firing of the element body. An insulating film with a uniform thickness can be easily formed on the R surface and the groove portion that constitute the structure.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view showing a conventional voltage nonlinear resistor;
Figures a and b are longitudinal cross-sectional views of the voltage nonlinear resistor targeted by the first invention, and Figures 3 a, b, and 4 are longitudinal cross sections of the voltage nonlinear resistor targeted by the second invention. FIG. 5 is a vertical sectional view showing an embodiment of the first invention. 5, 7, 9, 11, 13... Qin body, 5A, 7A, 7B,
......R chamfer, 9A...groove, 6,8
A, 8B, 10, 12...Insulating film, 14...
... Ceramic pedestal, 15 ... Saya, 16 ... Mask material, 17 ... Auxiliary village, 18 ... Insulating film forming material, 1
9... Lid. Figure 1 Figure 2 Figure 4 Figure 3 Figure 5

Claims (1)

[Claims] 1. In manufacturing a voltage nonlinear resistor in which an R chamfer is formed on the peripheral edge of the element body and an insulating film is formed on the peripheral surface of the element body including the R chamfered part, A compression molded or calcined element is placed on a heat-resistant pedestal, an insulating film forming material is placed near the element, the fired pod is covered with a lid made of the same material as the fired pod, and heated; 1. A method for manufacturing a voltage nonlinear resistor, which comprises forming an insulating film on the surface of the element by firing the element and evaporating or sublimating an insulating film forming material to cause a gas-solid phase reaction on the surface of the element. 2 A round chamfer is formed on the peripheral edge of the element body, and a groove is formed in the circumferential direction of the element body surface excluding the electrode forming surface and the edge is rounded with a round chamfer, so that the peripheral surface of the element body including each R chamfered part and In manufacturing a voltage nonlinear resistor with an insulating film formed in the groove, a compression-molded or calcined element is placed on a heat-resistant pedestal in a firing pod, and an insulating film-forming material is placed near the element. The fired pod is covered with a lid made of the same material as the fired pod and heated, and the element is fired by a gas phase-solid reaction on the surface of the element due to evaporation or sublimation of the insulating film forming material. A method for manufacturing a voltage nonlinear resistor, characterized by forming an insulating film on the body surface.