JPH1126207A - Manufacturing method of nonlinear resistor - Google Patents

Abstract

(57) [Problem] To provide a large-sized and large-capacity non-linear resistor excellent in discharge withstand characteristics and charging life by reducing variation in resistance of a sintered body. SOLUTION: A raw material is put into a cylindrical container provided with an arm and a shock plate rotating at a high speed, and the raw material is caused to collide with an impact plate while being rotated at a high speed to grind the raw material (pulverizing step). The obtained powder is placed in a cylindrical container equipped with a stirring blade, and the stirring blade is rotated to force the powder to flow,
The powder is mixed (mixing step). After a predetermined mixed state is obtained, a predetermined amount of a binder is added by spraying the powder while keeping the powder in a fluid state. As a result, the powder agglomerates to obtain substantially spherical granules having a predetermined particle size (aggregation step). Subsequently, by sequentially performing a molding step, a firing step, a high-resistance layer forming step, and an electrode forming step, a non-linear resistor composed of the sintered body 1, the high-resistance layer 2, and the electrode 3 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a nonlinear resistor mainly composed of zinc oxide used for an arrester, a surge absorber and the like.

[0002]

2. Description of the Related Art In general, a surge arrester and a surge absorber are used to suppress an abnormal voltage in a power system and an electronic device circuit and protect the power system and the electronic device. The lightning arresters and surge absorbers use non-linear resistors to protect the system and circuits by showing insulation characteristics at normal voltage and exhibiting low resistance characteristics when abnormal voltage is applied. ing.

An outline of a method of manufacturing this nonlinear resistor is as follows. First, as a raw material, ZnO is used as a main component, and at least as a sub-component for expressing a voltage-current nonlinear characteristic, for example, as described in JP-A-5-234716, Bi ₂ O ₃ , Sb ₂ O ₃ , Co
O, NiO, Mn ₂ O _{3 and the} like are added. Then, after sufficiently mixing these raw materials with water and an organic binder, the raw materials are granulated by a spray drier or the like, formed, and sintered. Thereafter, a high-resistance substance for preventing creeping flashing is applied to the side surface of the sintered body, and refired to form a high-resistance layer. Finally, both ends of the sintered body are polished and electrodes are attached to complete the non-linear resistor.

[0004]

In recent years, power systems have been increasing in capacity to reduce transmission costs. Since nonlinear resistors used in such large-capacity lightning arresters are required to handle extremely large surge energy, measures such as increasing the capacity of nonlinear resistors and increasing the number of parallel-connected resistors are required. Yes, it is.

[0005] Among these means, the increase in the number of parallel-connected elements has an upper limit due to a problem in characteristics such as an easy imbalance in current sharing. Therefore, it is necessary to increase the capacity of the non-linear resistor. Will be. In response to the demand for large capacity, the dimensions of the nonlinear resistor obtained by the current manufacturing method are as follows:
Although the diameter may be as large as 80 to 120 mm and the thickness as large as 20 to 50 mm, such a large nonlinear resistor has the following problems.

That is, in a sintered body used for a large-sized non-linear resistor, abnormal grain growth of ZnO crystal grains occurs due to the partial non-uniformity of the sintering temperature during sintering, and the resistance value is increased. Variation easily occurs. Further, there is a problem that current concentrates on a portion having a low resistance, which causes a decrease in withstand voltage characteristics.

As described above, when a large-sized non-linear resistor is manufactured by the conventional manufacturing method, a partial variation in the resistance value occurs in the sintered body, and the discharge withstand characteristics and the charging life characteristics deteriorate. Problems occur.

The present invention has been made in consideration of the above points, and an object of the present invention is to reduce the variation in the resistance value of a sintered body, thereby achieving a large-sized battery having excellent discharge withstand characteristics and charge application life characteristics. An object of the present invention is to provide an excellent manufacturing method capable of manufacturing a large-capacity nonlinear resistor.

[0009]

In order to achieve the above object, a method for manufacturing a non-linear resistor according to claims 1 and 2 comprises zinc oxide as a main component and exhibits at least voltage-current non-linear characteristics. A method of manufacturing a non-linear resistor including a sub-component is characterized in that processing of raw materials before forming and sintering is improved.

That is, in the method according to the first aspect, a pulverizing step of pulverizing raw materials in a dry state, a mixing step of mixing powders in a dry state, and spraying a liquid material on the powders in a dry state. And at least one step selected from the aggregating step of aggregating the powder by the method.

Further, the method according to claim 2 is characterized in that a pulverizing step of pulverizing the raw material in a dry state, a mixing step of mixing the powder obtained in the pulverizing step in a dry state, A liquid material is sprayed on the powder in a dry state to aggregate the powder.

According to the method of the first or second aspect having the above configuration, the following operation can be obtained.
First, in the pulverizing step of pulverizing the raw material in a dry state,
Compared to the case of pulverizing a slurry-like raw material, a large pulverizing power is obtained without lowering of the pulverizing power due to buffering of water, so that a uniform and fine powder can be obtained. Then, by using such a powder for granulation, as a result, uniform granules without uneven distribution of components can be obtained.

Further, in the mixing step of mixing the powder in a dry state, compared to the case of mixing the slurry-like raw materials, there is no problem such as settling in water, and sufficient mixing of the whole powder is achieved. Since a force can be applied, the powder can be uniformly mixed. Then, by granulating using the powder thus mixed, uniform granules without uneven distribution of components can be obtained.

Further, in the aggregating step of aggregating the powder in a dry state, components having low wettability to water are not unevenly distributed near the surface as compared with the case where the raw material in a slurry state is sprayed and dried. Uniform spherical granules can be obtained.

Therefore, according to the method of the present invention, at least any one of the functions can be obtained according to the selected step. It is possible to obtain non-uniform granules and to produce a non-linear resistor having excellent discharge withstand characteristics. When two or more steps are included, a synergistic effect is obtained. According to the method of claim 2, since all of the three steps of the pulverizing step, the mixing step, and the aggregating step are included, a synergistic effect of the above-mentioned three uniformities provides a non-discharge capacity having more excellent discharge withstand characteristics. A linear resistor can be manufactured.

According to a third aspect of the present invention, in the method of the first or second aspect, a specific procedure of the pulverizing step is characterized. That is, the method according to claim 3 is characterized in that, in the pulverizing step, a powder having a particle size smaller than a preset particle size is taken out as an object to be crushed, and a powder having a larger particle size is crushed again. According to this procedure, a powder smaller than a predetermined particle size is taken out, and only a powder having a larger particle size is pulverized again.
Since the reduction in the crushing power due to the powder having a small particle size can be prevented, the crushing efficiency can be improved.

The method according to claims 4 and 5 is characterized in that, in the method according to any one of claims 1 to 3, a specific pulverization method in the pulverization step is characterized. First,
According to a fourth aspect of the present invention, in the pulverizing step, the raw material is pulverized by rotating the raw material at a high speed and causing the raw material to collide with an impact plate. The method according to claim 5 is characterized in that in the pulverizing step, the raw material is pulverized by causing the raw material to collide with a high-pressure gas. In any of the methods, a large crushing force can be obtained by directly colliding the raw materials, so that the raw materials can be efficiently crushed and uniform and fine powder can be obtained.

The method according to claims 6 and 7 is characterized in that, in the method according to any one of claims 1 to 5, a specific mixing method of the mixing step is used. First,
According to a sixth aspect of the present invention, in the mixing step, the powder is mixed by rotating the powder at a high speed and flowing the powder. The method according to claim 7 is characterized in that, in the mixing step, the powder is mixed by flowing the powder using a high-pressure gas. In any of the methods, by mixing the powder in a fluidized state, a sufficient mixing force can be given to the entire powder, so that the powder can be uniformly mixed.

The method according to claim 8 is characterized in that, in the method according to any one of claims 1 to 7, a specific coagulation method of the coagulation step is used. That is, the method according to claim 8 is characterized in that in the aggregating step, the powder is fluidized in a dry state, and the powder is aggregated by spraying a binder onto the flowing powder. . According to this method, uneven distribution of components in the granules can be prevented by spraying the binder on the powder in a dry state and in a fluid state, and uniform spherical granules can be obtained.

The method according to the ninth and tenth aspects is characterized in that, in the method according to any one of the first to eighth aspects, a method of adding an auxiliary component in the aggregation step is used. First, a method according to a ninth aspect is characterized in that in the agglomeration step, the powder is fluidized in a dry state, and the flowing powder is sprayed with a subcomponent as a solution. According to a tenth aspect of the present invention, in the method according to the ninth aspect, the auxiliary component includes a material selected from aluminum, boron, and silver.

In the method according to the ninth and tenth aspects, the auxiliary component can be uniformly dispersed in the powder by spraying the auxiliary component as a solution. That is, when a material such as aluminum, boron, or silver is added as it is as an auxiliary component, uniform dispersion is difficult because the content of these materials is relatively small. , Uniform dispersion becomes possible.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of embodiments to which the method for manufacturing a non-linear resistor according to the present invention is applied will be specifically described below with reference to the drawings.

[First Embodiment] First, claim 4, 6, 8
A first embodiment to which the inventions described in (1) are applied will be described. ZnO as a main component, and Bi ₂ O ₃ ,
1 mol% each of Sb ₂ O ₃ , CoO, NiO, Mn ₃ O
₄ is weighed at 0.5 mol% for each material. This raw material is put into a cylindrical container provided with a high-speed rotating arm and a shock plate, and collides with the shock plate while rotating the raw material at high speed to grind the raw material (pulverizing step). The obtained powder is placed in a cylindrical container equipped with a stirring blade, and the powder is mixed by rotating the stirring blade and forcibly flowing the powder (mixing step). After a predetermined mixing state is obtained, a predetermined amount of a binder, for example, a 3% PVA solution is used in 5% of the powder amount while rotating the stirring blade in the same cylindrical container to keep the powder in a fluid state. Then, it is added by spraying the powder.
While the stirring blade is continuously rotated to keep the powder in a fluidized state, the powder is agglomerated to obtain substantially spherical granules having a predetermined particle size, for example, 100 μm (aggregation step).

Next, the granules are placed in a mold and pressurized to a predetermined shape such as a disk, for example, a diameter of 100 mm and a height of 25 m.
m is obtained by molding into a m (molding step). The shaped body thus obtained is calcined in air at, for example, 500 ° C. to remove the added binder, and further baked in air for 12 hours.
Firing at 00 ° C. for 2 hours (firing step). This allows
A sintered body 1 as shown in FIG. 1 can be obtained. Then, after applying an insulator having high resistance by firing on the side surface of the sintered body 1, the high resistance layer 2 is formed by firing this (high resistance layer forming step). Thereafter, the electrodes 3 are formed by polishing both end surfaces of the sintered body 1 and spraying aluminum on the both end surfaces (electrode forming step). Thus, a non-linear resistor as shown in FIG. 1 can be obtained.

The electrical characteristics of the nonlinear resistor obtained as described above will be described with reference to FIG. here,
FIG. 2 shows the discharge withstand characteristic A of the non-linear resistor according to the present embodiment.
1 is a graph showing a comparison between a discharge resistance characteristic B of a non-linear resistor manufactured by a conventional method and a non-linear resistor manufactured by a conventional method. More specifically, FIG. 2 shows that under the condition that a lightning impulse (4/10) current is applied while its current value is sequentially increased,
A discharge withstand test is performed on each of the 50 non-linear resistors according to the present embodiment and the conventional example, and the discharge withstand characteristics are obtained with the ratio of the non-linear resistors that withstand the current value as a pass rate.

As shown in FIG. 2, in the conventional example B, when the impulse current increases to 100 kA, the pass rate starts to decrease from 100%, and the pass rate decreases to about 55% for the 120 kA impulse current. On the other hand, in the embodiment A1, the pass rate is 100% even for the impulse current of 130 kA.
Obviously, the discharge tolerance characteristics of the non-linear low antibody of this example are significantly improved as compared with the conventional example.

As described above, the reason why the discharge withstand characteristic is improved in the present embodiment as compared with the conventional example is considered as follows.

That is, conventionally, water and a binder were added to the raw material powder, and the raw material was pulverized and mixed as a slurry.
Therefore, at the time of pulverization, water buffered and hindered the pulverization. At the time of mixing, a component having a large atomic weight settled, and sufficient mixing was not possible. Further, at the time of granulation, since the raw material in the form of slurry was sprayed and dried, components having low wettability to water were unevenly distributed near the surface.

On the other hand, in the present embodiment, since the raw material is caused to directly collide with the impact plate, a large crushing force can be obtained, so that a uniform and fine powder can be obtained. Further, since the powder is caused to flow while rotating, a sufficient mixing force can be given to the entire fluid, and the fluid can be uniformly mixed. Furthermore, since the powder is fluidized and agglomerated in a spherical shape, uneven distribution of components in the granules can be prevented.

For the above reasons, in this embodiment,
Because it is possible to obtain uniform granules without uneven distribution of components,
It is considered that a uniform non-linear low antibody can be obtained, and the discharge withstand characteristics can be improved without causing partial variation in resistance value. Along with this, although not shown, the charging life characteristics can also be improved.

[Second Embodiment] Next, a third embodiment will be described.
A second embodiment to which each of the inventions described in 6 and 8 is applied will be described. In the second embodiment, the specific procedure of the pulverizing step in the first embodiment is changed.

In this embodiment, first, the raw materials are weighed in the same manner as in the first embodiment. Next, a pulverizing step is performed using a cylindrical container equipped with an arm rotating at a high speed, an impact plate, and a device for separating powder having a predetermined particle size, for example, less than 1 μm.
That is, the raw material is charged into the cylindrical container, and the raw material is rotated at a high speed to collide with the impact plate to pulverize the raw material. In this pulverization step, powder smaller than a predetermined particle size is taken out as a material to be pulverized, and powder larger than the predetermined particle size is returned to a pulverization container to be further pulverized. After the above-described pulverizing step, subsequent steps similar to those in the first embodiment, that is, a mixing step, an aggregation step, a forming step, a firing step, a high-resistance layer forming step, and an electrode forming step are sequentially performed. Thus, a non-linear low antibody as shown in FIG. 1 can be obtained.

The discharge withstand characteristics of the non-linear low antibody obtained as described above will be described with reference to FIG. Here, FIG. 3 shows the discharge withstand characteristic A2 of the nonlinear resistor according to the present embodiment, the discharge withstand characteristic B of the nonlinear resistor manufactured by the conventional method, and the nonlinear resistance according to the first embodiment. It is a graph which shows and compares discharge tolerance characteristic A1 of a body.
The test conditions and the number of samples are as described in the first embodiment.

As shown in FIG. 3, the first embodiment A1
In the example, when the impulse current increases to 140 kA, the pass rate decreases to about 55%. On the other hand, in the embodiment A2, a high pass rate exceeding 90% is obtained even for the impulse current of 140 kA. Is shown. Obviously, the discharge withstand characteristics of the non-linear low antibody of this embodiment are further improved as compared with the above-described first embodiment.

As described above, in this embodiment, the reason why the discharge endurance characteristic is further improved as compared with the first embodiment is as follows.
It is considered as follows.

That is, generally, in the pulverizing step,
When finer particles coexist, the finer particles buffer the crushing of the larger particles and consequently hinder crushing. On the other hand, in the present embodiment, particles smaller than a predetermined particle size are taken out as powder to be pulverized, so that the pulverization efficiency of larger particles can be increased.

For this reason, in the present embodiment, more uniform granules can be obtained as compared with the first embodiment, so that the microstructure of the non-linear antibody is also uniform.
It is considered that the discharge withstand capability can be improved without causing partial variation in the resistance value. Along with this, although not shown, the charging life characteristics can also be improved.

[Third Embodiment] Next, claims 5, 6, and 8 will be described.
Third Embodiment A description will be given of a third embodiment to which each invention described in (1) is applied. In the third embodiment, a specific pulverizing method is changed in the first embodiment.

In this embodiment, first, the raw materials are weighed in the same manner as in the first embodiment. Next, a pulverizing step is performed using a container provided with a device for injecting high-pressure air into the inside and a device for supplying a raw material along with the injection of air. That is, the raw material is charged into the air stream of the container, and the raw material is crushed by colliding the raw materials. After this pulverizing step, the subsequent steps similar to those of the first embodiment, that is, a mixing step, an aggregation step, a forming step, a firing step, a high-resistance layer forming step, and an electrode forming step are sequentially performed. A non-linear low antibody as shown in FIG. 1 can be obtained.

The discharge tolerance characteristics of the non-linear low antibody obtained as described above will be described with reference to FIG. Here, FIG. 4 is a graph showing a comparison between the discharge withstand characteristic A3 of the nonlinear resistor according to the present embodiment and the discharge withstand characteristic B of the nonlinear resistor manufactured by the conventional method. The test conditions and the number of samples are as described in the first embodiment.

As shown in FIG. 4, in the conventional example B, when the impulse current increases to 100 kA, the pass rate starts to decrease from 100%, and the pass rate decreases to about 55% for an impulse current of 120 kA. On the other hand, in the present embodiment A3, the pass rate is 100% even with an impulse current of 130 kA.
Obviously, the discharge withstand characteristics of the non-linear low antibody of this example are as follows.
As in the first embodiment, it is greatly improved as compared with the conventional example.

As described above, in this embodiment, the reason why the discharge endurance characteristic is improved as compared with the conventional example can be considered almost the same as in the first embodiment.

That is, in the first embodiment, a large crushing force is obtained by directly colliding the raw material with the impact plate, but in the present embodiment, a sufficiently large crushing force is obtained by directly colliding the raw materials. Crushing power can be obtained. In addition, the point that the entire fluid can be sufficiently mixed by flowing the powder while rotating and the point that the uneven distribution of components in the granule can be prevented by allowing the powder to flow and agglomerate into a spherical shape, This is exactly the same as the first embodiment.

Therefore, in this embodiment, as in the first embodiment, uniform granules without uneven distribution of components can be obtained, so that a uniform non-linear low antibody can be obtained and a partial resistance value can be obtained. It is considered that the discharge withstand capability can be improved without causing the variation in the discharge capacity. Along with this, although not shown, the charging life characteristics can also be improved.

[Fourth Embodiment] Next, a fourth embodiment will be described.
A fourth embodiment to which each of the inventions described in the above is applied will be described. The fourth embodiment is different from the first embodiment in that the specific flow method for mixing and coagulation is changed.

In this embodiment, first, as in the first embodiment, the raw materials are weighed and pulverized (pulverizing step). Next, the powder obtained by this pulverizing step is mixed. That is, the powder is put into a container equipped with a device for blowing high-pressure air from below, and the powder is floated by high-pressure air.
Mix while flowing (mixing step). After a predetermined mixing state is obtained, a predetermined amount of a binder, for example, a 3% PVA solution is added while spraying 5% of the powder amount while keeping the powder in a fluid state in the same container. The powder is agglomerated while continuously blowing the high-pressure air to keep the powder in a fluid state, so that substantially spherical granules having a predetermined particle size, for example, 100 μm can be obtained (aggregation step). After this aggregation step, the subsequent steps similar to those of the first embodiment, that is, the forming step, the sintering step, the high-resistance layer forming step, and the electrode forming step are sequentially performed to obtain the structure shown in FIG. Non-linear low antibodies can be obtained.

The discharge withstand characteristics of the non-linear resistor obtained as described above will be described with reference to FIG. Here, FIG. 5 is a graph showing a comparison between the discharge withstand characteristic A4 of the nonlinear resistor according to the present embodiment and the discharge withstand characteristic B of the nonlinear resistor manufactured by the conventional method. The test conditions and the number of samples are as described in the first embodiment.

As shown in FIG. 5, in the conventional example B, when the impulse current increases to 100 kA, the pass rate starts to decrease from 100%, and the pass rate decreases to about 55% for the 120 kA impulse current. On the other hand, in the embodiment A4, the pass rate is 100% even for the impulse current of 130 kA.
Obviously, the discharge withstand characteristics of the non-linear low antibody of this example are as follows.
As in the first embodiment, it is greatly improved as compared with the conventional example.

As described above, in this embodiment, the reason why the discharge endurance characteristics are improved as compared with the conventional example can be considered almost the same as in the first embodiment.

That is, in this embodiment, as in the first embodiment, a large crushing force can be obtained by directly colliding the raw material with the impact plate. Further, in the first embodiment, the powder is caused to flow while rotating, but in the present embodiment, the powder is caused to flow while maintaining the powder in a floating state by high-pressure air. In addition to being able to mix well, the powder can be agglomerated into a spherical shape while flowing, and uneven distribution of components in the granules can be prevented.

Therefore, in this embodiment, as in the first embodiment, granules without uneven distribution of components can be obtained, so that a uniform non-linear resistor can be obtained and partial variation in resistance value can be obtained. It is considered that the discharge withstand characteristics can be improved without causing the occurrence of the electric discharge. Along with this, although not shown, the charging life characteristics can also be improved.

[Fifth to seventh embodiments]
Fifth to seventh embodiments to which the inventions described in 6, 8, and 10 are applied will be described. In the fifth to seventh embodiments, aluminum, boron, and silver are further added in the aggregation step of the manufacturing steps described in the first embodiment.

In the fifth to seventh embodiments, first, as in the first embodiment, the raw materials are weighed, and the same pulverizing step and mixing step are performed to obtain a predetermined mixed state. While the powder is kept in a fluid state by rotating the stirring blade in the same cylindrical container, any one material of aluminum, boron and silver is added by spraying in the form of an aqueous solution. Specifically, a predetermined amount of aluminum, for example, Al ₂ O ₃
0.005 mol% in terms of boron, a predetermined amount in the form of a boric acid aqueous solution, for example, 0.005 mol% in terms of B ₂ O ₃ , and silver in the state of a silver nitrate aqueous solution, for example, Ag ₂ O. 0.005mol converted to
% By spraying. Subsequently, as in the first embodiment, while keeping the powder in a fluid state, 3% PVA
The solution is added by spraying on the powder to obtain approximately spherical granules. After this aggregation step, the subsequent steps similar to those of the first embodiment, that is, the forming step, the sintering step, the high-resistance layer forming step, and the electrode forming step are sequentially performed to obtain the structure shown in FIG. Non-linear low antibodies can be obtained.

The electrical characteristics of the non-linear resistors according to the fifth to seventh embodiments obtained as described above are shown in FIGS.
This will be described with reference to FIG. Here, FIG. 6 to FIG.
To A withstand discharge characteristic A of each nonlinear resistor according to the seventh to seventh embodiments.
5 to A7, and the discharge resistance characteristics A11 to A11 of the non-linear resistor produced by including the same kind and the same amount of subcomponents from the pulverization step.
6 is a graph showing a comparison with A13. That is, FIG.
Is a graph showing a comparison between the respective discharge endurance characteristics A5 and A11 of the fifth embodiment in which the same amount of aluminum is added and the comparative example, and FIG. 7 is a sixth embodiment in which the same amount of boron is added. And withstand discharge characteristics A6, A of Comparative Examples
FIG. 8 is a graph showing a comparison between No. 12 and FIG. 8, and FIG.
13 is a graph showing a comparison of FIG. In addition, each comparative example is
Except that the same subcomponent as in the fifth to seventh embodiments is contained as a raw material from the pulverizing step, it is produced by the same method as in the first embodiment.

As shown in FIGS. 6 to 8, Comparative Example A1
1 to A13, the impulse current is 1
When the pass rate increases to 40 kA, the pass rate decreases to about 55%, whereas in the fifth to seventh embodiments A5 to A7, the pass rate decreases by 90% with respect to the impulse current of 140 kA.
It shows a high pass rate exceeding. Apparently, the discharge tolerance characteristics of the non-linear low antibodies of the fifth to seventh embodiments are further improved as compared with the comparative example according to the above-described first embodiment.

The reason why the discharge withstand capability is further improved in the fifth to seventh embodiments as compared with the comparative example is considered as follows.

That is, since the amount of addition of aluminum, boron or silver is smaller than that of other subcomponents, it is difficult to uniformly disperse the material in the comparative example in which this material is simply added from the pulverization step. On the other hand, in the fifth to seventh embodiments, since they are added as an aqueous solution, they can be more uniformly dispersed, and the uneven distribution of these subcomponents can be prevented.

For these reasons, in the fifth to seventh embodiments, compared with the comparative example according to the first embodiment,
It is considered that a non-linear resistor having a more uniform structure can be obtained, and discharge resistance characteristics can be improved without causing partial resistance value variation. Along with this, the service life characteristics can also be improved.

[Other Embodiments] The present invention is not limited to the above embodiments, and various other modifications can be made. For example, in the first to seventh embodiments, an oxide is used as a raw material. However, the present invention is not limited to this. , Carbonates and oxalates can provide the same effect. The material to be used and the specific composition thereof can be appropriately selected, and the sizes of the molded body and the sintered body can also be appropriately selected.

Further, specific procedures, methods, conditions, and the like of the pulverizing step, the mixing step, and the agglomeration step according to the present invention can be freely selected and freely combined. Can also be selected as appropriate. Similarly, specific procedures, methods, conditions, and the like of each step subsequent to these steps can be appropriately selected.

[0061]

As described above, according to the present invention,
In a method for producing a non-linear resistor comprising zinc oxide as a main component and at least an auxiliary component exhibiting voltage-current non-linear characteristics, a pulverizing step of pulverizing raw materials in a dry state and a mixing step of mixing powders in a dry state Agglomeration step of agglomerating the powder by spraying a liquid material onto the powder in a dry state, thereby obtaining granules without uneven distribution of components by including at least one step selected from the following. And the variation of the resistance value of the sintered body can be reduced.
A large-capacity non-linear resistor can be provided.

In the pulverizing step, powder having a particle size smaller than a predetermined value is taken out as a material to be pulverized, and powder having a larger particle size is pulverized again.
Since a reduction in crushing power due to powder having a small particle size can be prevented and crushing efficiency can be improved, a nonlinear resistor having more excellent characteristics can be provided.

Further, since the powder is made to flow in a dry state and the solution of the binder and the auxiliary component is added to the flowing powder by spraying, the uneven distribution of the components in the granules can be reduced. To obtain more uniform granules,
A non-linear resistor having more excellent characteristics can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a non-linear resistor according to a first embodiment of the present invention.

FIG. 2 is a graph showing discharge withstand characteristics of the nonlinear resistor according to the first embodiment of the present invention.

FIG. 3 is a graph showing discharge withstand characteristics of a nonlinear resistor according to a second embodiment of the present invention.

FIG. 4 is a graph showing discharge withstand characteristics of a non-linear resistor according to a third embodiment of the present invention.

FIG. 5 is a graph showing discharge withstand characteristics of a non-linear resistor according to a fourth embodiment of the present invention.

FIG. 6 is a graph showing discharge withstand characteristics of a non-linear resistor according to a fifth embodiment of the present invention.

FIG. 7 is a graph showing discharge withstand characteristics of a non-linear resistor according to a sixth embodiment of the present invention.

FIG. 8 is a graph showing the discharge withstand characteristics of the non-linear resistor according to the seventh embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Sintered body 2 ... High resistance layer 3 ... Electrode

Claims (10)

[Claims] 1. A method for producing a non-linear resistor comprising zinc oxide as a main component and at least an auxiliary component exhibiting a non-linear voltage-current characteristic, comprising: a pulverizing step of pulverizing raw materials in a dry state; And a coagulation step of coagulating powder in a dry state. 2. A method for producing a non-linear resistor comprising zinc oxide as a main component and at least an auxiliary component exhibiting voltage-current non-linear characteristics, comprising: a pulverizing step of pulverizing a raw material in a dry state; A method for producing a nonlinear resistor, comprising: a mixing step of mixing the obtained powders in a dry state; and an aggregation step of aggregating the powders mixed and dried in the mixing step. 3. The method according to claim 1, wherein in the pulverizing step, a powder having a particle size smaller than a preset particle size is taken out as an object to be crushed, and a powder having a larger particle size is crushed again. Manufacturing method of linear resistor. 4. The non-linear resistor according to claim 1, wherein in the pulverizing step, the raw material is pulverized by rotating the raw material at a high speed and colliding with a shock plate. Manufacturing method. 5. The non-linear resistor according to claim 1, wherein in the pulverizing step, the raw material is pulverized by colliding the raw material with a high-pressure gas. Method. 6. The non-linear method according to claim 1, wherein in the mixing step, the powder is mixed by rotating the powder at a high speed and flowing the powder. Manufacturing method of resistor. 7. The nonlinear resistor according to claim 1, wherein in the mixing step, the powder is mixed by flowing the powder using a high-pressure gas. Manufacturing method. 8. The method according to claim 1, wherein, in the aggregating step, the powder is fluidized in a dry state, and the powder is aggregated by spraying a binder onto the flowing powder. The method for producing a non-linear resistor according to any one of the above. 9. The method according to claim 1, wherein in the aggregating step, the powder is fluidized in a dry state, and the flowing component is sprayed with a subcomponent as a solution. 5. A method for manufacturing a non-linear resistor according to any one of the above. 10. The method according to claim 9, wherein the sub-component includes a material selected from aluminum, boron and silver.