JP3270618B2 - Voltage non-linear resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage non-linear resistor mainly composed of zinc oxide, and more particularly to a voltage non-linear resistor using two or more stacked resistors.

[0002]

2. Description of the Related Art Conventionally, resistors containing zinc oxide as a main component and small amounts of additives such as silicon dioxide, antimony oxide, nickel oxide and manganese oxide have exhibited excellent voltage non-linearity. It is widely known and is used for lightning arresters and the like by utilizing its properties.

As an example, when electrodes are provided on both end surfaces of an element main body containing zinc oxide as a main component in order to improve the discharge resistance, as shown in FIG. The electrode 1 extends to the region of the high resistance layer 12 provided on the side surface of
3 is disclosed in JP-A-60-2820.
No. 5 discloses this.

[0004]

As described above, in the voltage non-linear resistor in which the electrode 13 is provided not only on the element body 11 but also on the high resistance layer 12, the potential distribution is made uniform and the surface of the element is creepage. By preventing discharge, the discharge withstand capability is improved as compared with a normal voltage non-linear resistor. However, it is still at an insufficient level to achieve a higher discharge withstand capability which has been strongly demanded in recent years. However, there is a problem that it is not possible to achieve a higher discharge withstand capability only by the technique disclosed in Japanese Patent Application Laid-Open Publication No. H11-163,036.

An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a voltage non-linear resistor capable of improving heat radiation characteristics when two or more capacitors are stacked and improving discharge withstand capability.

[0006]

A voltage non-linear resistor according to the present invention is a disc-shaped element body mainly composed of zinc oxide, which is used by being stacked in two or more pieces, and a side face of the element body. In the voltage non-linear resistor composed of the high resistance layer provided on the element body and the electrodes provided on both end surfaces of the element body, at least one electrode has a protruding portion exceeding the high resistance layer provided on the side surface of the element body. The width of the portion of the protruding portion that covers the high resistance layer from the end surface of the element body and the high resistance layer is 10% or less of the thickness of the element body, and the density of the protruding portion is other than the protruding portion. Is smaller than the density of the electrodes.

Further, an example of a manufacturing method suitable for the voltage non-linear resistor of the present invention is the method of manufacturing a voltage non-linear resistor having the above-described configuration, wherein the element main body on a disk mainly composed of zinc oxide is formed. After forming a voltage non-linear resistor composed of a high resistance layer provided on the side surface of the element body, a masking tape is provided at a position on the side surface of the high resistance layer where no protruding portion is provided, and the electrode material is thermally sprayed. Alternatively, the width of the protrusion from the surface of the high-resistance layer is controlled by the thickness of the masking tape by applying a paste containing an electrode material and baking the paste.

[0008]

In the above-described structure, by providing the electrode with a protruding portion exceeding the high resistance layer provided on the side surface of the element body,
In particular, it is possible to improve the heat radiation characteristics when two or more capacitors are stacked, to further uniform the potential distribution, and to further improve the discharge resistance. When the width of the protruding portion is 0.03 mm or more, when the width of the protruding portion covering the high-resistance layer is 10% or less of the thickness of the element body, and when the thickness of the electrode is 0.03 mm or more. In the case where the protruding portion is present at 20% or more of the outer periphery, as can be seen from the following examples, the discharge withstand capability can be further improved, which is preferable.

If the density of the protruding portion is smaller than the density of the other portions, for example, if the density difference is 5% or more, the heat radiating action is enhanced at the protruding portion, and the portion that does not protrude removes the internal heat to the outside. It is preferable because it can maintain the effect of heat transfer.Furthermore, as a method of forming the protruding portion, any method can be used as long as the protruding portion can be formed by any method, but in particular, thermal spraying or paste using masking tape on the side surface When baked after application,
A simple process is preferable because the protrusion can be controlled.

[0010]

EXAMPLE In order to obtain a voltage non-linear resistor mainly composed of zinc oxide, first, a zinc oxide raw material adjusted to a predetermined particle size and Bi ₂ O ₃ , Co ₃ O ₄ , MnO ₂ , adjusted to a predetermined particle size are used. Sb ₂ O ₃ , Cr ₂ O ₃
A predetermined amount of an additive composed of, for example, SiO ₂ , NiO, etc. is mixed by a disper mill and then granulated by a spray dryer to obtain a granulated product. After granulation, it is formed into a predetermined shape under a forming pressure of 800 to 1000 kg / cm ² . Then, the temperature of the formed body is raised and lowered 30
Preliminary calcination is performed at a temperature of 800 to 1000 ° C. for 1 to 5 hours at a temperature of 70 ° C./hr. It is preferable to heat-treat the molded body at a temperature rising / falling rate of 10 to 100 ° C./hr at a temperature of 400 to 600 ° C. for a holding time of 1 to 10 hours before calcination to scatter and remove the binder and the like.

Next, a side surface high resistance layer is formed on the side surface of the pre-fired body. In the present invention, bismuth compound, antimony compound, a mixture paste for a side surface high resistance layer obtained by adding ethyl cellulose, butyl carbitol, n-butyl acetate and the like as an organic binder to a predetermined amount of a silicon compound and the like, 30 to 30
Apply to the side of the calcined body to a thickness of 0 μm. Next, the temperature is raised and lowered at a rate of 40-60 ° C./hr, and a maximum holding temperature of 1000-1300.
Main firing is performed at a temperature of 3 ° C. for 3 to 7 hours. Then, SiC both end surfaces of the obtained voltage non-linear resistor, Al ₂ O _3, water preferably by # 400 to 2000 equivalent abrasives such as diamond polishing using an oil.

What is important in the present invention is that electrodes are formed on both polished end faces so as to protrude beyond the high resistance layer provided on the side face of the element body. That is, after masking a position on the side of the high-resistance layer of the basic non-linear resistor obtained as described above on the side surface of the high-resistance layer with a masking tape, an electrode material such as aluminum is sprayed by a spraying device. The protruding portion is formed by a method, a method of applying and baking a silver paste after masking, or a method of bonding a metal plate processed in advance to a predetermined size and shape to an electrode by diffusion bonding or the like. In the method using a masking tape, the width of the high-resistance layer protruding from the surface can be controlled by changing the thickness of the tape. If the protruding portion is formed on at least one side, 2
At least one protruding portion can be provided on the joint surface when a plurality of pieces are stacked.

FIGS. 1 and 2 are diagrams for explaining the protruding portion in the voltage nonlinear resistor according to the present invention. FIG.
In the figure, 1 is a disk-shaped element main body containing zinc oxide as a main component, 2 is a high resistance layer provided on a side surface of the element main body 1, 3 is an electrode provided on both end surfaces of the element main body 1 and the high resistance layer 2 A protruding portion 4 is formed on at least one of the electrodes 3 beyond the high resistance layer 2 provided on the side surface of the element body 1.

In the example shown in FIG. 1, a is the width of the protruding portion 4 protruding from the surface of the high-resistance layer 2, and b is the height of the protruding portion 4 covering the element layer 1 and the high-resistance layer 2. The width of the covering from the end face of the resistance layer 2, c is the thickness of the electrode 3 on the element body 1 and the high resistance layer 2, and in the example shown in FIG.
Indicates a portion where is present.

Hereinafter, an actual example will be described. According to the manufacturing method described above, each of the protruding portions a of the electrode,
Samples Nos. 1 to 25 of the present invention in which the dimensions of b, c, and d were formed as shown in Table 1 below, and the density difference between the protruding portion and the other portion was set as shown in Table 1 below And Comparative Example N
o. A voltage non-linear resistor of 1 was prepared, and the discharge resistance of each voltage non-linear resistor was determined to be 4/10 μs. Here, the 4 / 10μs discharge withstand capacity means that three identical samples are stacked and tested, the energy is calculated by integrating the current waveform and the voltage waveform, and the energy value that has not been destroyed is divided into three equal parts. Determined by Table 1 shows the results.

[0016]

[Table 1]

From the results shown in Table 1, it can be seen that Samples Nos. 1 to 25 of the present invention in which the protruding portion was formed had improved discharge withstand capability as compared with Comparative Sample No. 1 in which the protruding portion was not provided. Was. In addition, the protrusion width a of the sample N
From the comparison between o.1 to 21 and No. 22, if it is 0.03 mm or more, the covering width b is about the present invention sample Nos. 1 to 21 and No. 2
3, the electrode thickness c is not more than 10% of the element thickness, and the electrode thickness c is 0.03 mm or more from the comparison of the present invention sample Nos. 1 to 21 and No. 24. As for the abundance ratio d, a comparison between Sample Nos. 1 to 21 of the present invention and No. 25 shows that a voltage non-linear resistor having a high discharge withstand capability can be obtained if it is at least 20% of the outer periphery of the element. I understood. Furthermore, it was found from the comparison between Sample No. 18 and other samples of the present invention that the difference in density between the protruding portion and other portions was preferably 5% or more.

[0018]

As is apparent from the above description, according to the present invention, since the electrode is provided with a protruding portion exceeding the high resistance layer provided on the side surface of the element body, especially when two or more are stacked. Can be improved, the potential distribution can be made more uniform, and the discharge withstand capability can be further improved. When the width of the protruding portion is 0.03 mm or more, when the width of the protruding portion covering the high-resistance layer is 10% or less of the thickness of the element body, the thickness of the electrode is 0.1 mm or less.
In the case of 03 mm or more, it is preferable that the protruding portion is present in 20% or more of the outer periphery because the discharge withstand capacity can be further improved.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining dimensions of each portion of a protruding portion in a voltage nonlinear resistor according to the present invention.

FIG. 2 is a diagram for explaining an existing ratio of a protruding portion in a voltage nonlinear resistor according to the present invention.

FIG. 3 is a diagram for explaining a state of an electrode of a conventional voltage non-linear resistor.

[Explanation of symbols]

1 element body, 2 high resistance layer, 3 electrodes, 4 protruding part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01C ^7/ 02-7/22

Claims (5)

(57) [Claims] 1. A disc-shaped element main body containing zinc oxide as a main component, a high-resistance layer provided on a side surface of the element main body, and two end faces of the element main body. portions in the voltage nonlinear resistor composed of a provided electrode, at least one of the electrodes, which have a protruding portion exceeds the high-resistance layer provided on a side surface of the device body, covering the high-resistance layer on the protruding portion
The width of the element body and the high-resistance layer
Not more than 10% of the thickness of the main body and the protrusion
The voltage non-linear resistor , wherein the density of the portion is lower than the density of the electrodes other than the protruding portion . 2. The voltage non-linear resistor according to claim 1, wherein the width of the protrusion from the surface of the high resistance layer is 0.03 mm or more. 3. The voltage non-linear resistor according to claim 1, wherein the thickness of the electrode having the protruding portion on the element body and the high resistance layer is 0.03 mm or more. 4. The voltage non-linear resistor according to claim 1, wherein the protruding portion is present on at least 20% of the outer periphery of the high resistance layer. 5. A voltage nonlinear resistor of the difference is 5% or more of claim 1, wherein the density of the electrode other than the density and protruding portion of the protruding portion.