JPH01216504A - Nonlinear resistor - Google Patents

Abstract

PURPOSE:To raise the temperature evenly for decreasing the inner stress and increase the resistance of joints against thermal stress, by fixing a plurality of blocks the principal component of which is zinc oxide with elastic and heat conductive bond. CONSTITUTION:When forming a nonlinear resistor 11, three sector blocks 2 having a pair ot adhering surfaces 4 set at an angle theta (for example 120 deg.) are formed by sintering. And then the adhering surfaces 4 of each block 2 are adhered to each other with bond 3 to form a cylindrical nonlinear resistor 1 and the upper and lower surfaces 5 and 6 thereof are polished to make said surfaces parallel. In adhering each block 2, unadhered portions 8 for positioning are formed at the edges along the curved surface of each adhering surface 4. Electrodes 7 are fixed between each nonlinear resistor 1 and at the same time a plurality of positioning strips 9 are fitted into the unadhered portions 8 of each nonlinear resistor 1 to form a long cylinder. Each nonlinear resistor 1 consists of three sector blocks 2 of about the same volume, therefore, electrical energy proof quantity approximately proportional to the number of the blocks can be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a non-linear resistor used in lightning arresters and the like.

(Prior art and problems to be solved by the invention) In general, in an integral non-linear resistor mainly composed of zinc oxide, by keeping the thickness of the non-linear resistor constant and increasing the outer diameter, When the volume is increased, the electrical energy resistance against lightning surges and switching surges does not increase in proportion to the increase in volume, but tends to saturate after increasing at a rate lower than the volume increase rate. Are known. Therefore, in cases where the energy withstand capacity must be set large due to lightning surge energy responsibility, the outer diameter of the nonlinear resistor becomes larger than necessary, resulting in a large lightning arrester or lightning arrester as a complete product. In the case of lightning arrester insulators used for power transmission lines during the earthquake, there were problems in that they could not be accommodated in the clearance of existing towers and that the towers needed to be reinforced. Further, there is a problem that not only is handling troublesome, but also the manufacturing cost increases.

Japanese Unexamined Patent Publication No. 56-54004 discloses that a plurality of fan-shaped bodies molded from a material containing zinc oxide are joined to each other by a glass lift on their radially extending sides, thereby producing a large-diameter one at low cost. A nonlinear resistor is described that can be manufactured. However, in this conventional configuration, since glass lift is used as the bonding material for the sector-shaped bodies, the entire body becomes solid like ceramics, and the bonding parts of each sector-shaped body become damaged due to the thermal stress generated due to the application of overvoltage. There is a problem in that it cracks and is easily destroyed.

(Object of the Invention) The present invention was made to solve the above-mentioned problems, and its first purpose is to increase the resistance to heat stress of the joint portion of each lump, and to
The object of the present invention is to provide a nonlinear resistor that can secure a required electric energy withstand capacity that is approximately proportional to the volume of each block. The second purpose is to provide a non-linear resistor that can be made smaller in diameter than an integrated one when given the same energy withstand capacity, and the third purpose is to provide a non-linear resistor that can be used by stacking them on top of each other. The object of the present invention is to provide a non-linear resistor that can be used.

(Means for Solving the Problems) In order to achieve the above object, in the non-linear resistor of the present invention, a plurality of lumps containing zinc oxide as a main component are bonded together using an adhesive having elasticity and heat conductivity. It is fixed with adhesive. It is preferable that the mass is formed into a fan-like shape, and the radially extending side surfaces of the mass are bonded to each other so that the mass is formed into a substantially cylindrical shape as a whole. Further, it is preferable that the lump has two planes that are substantially orthogonal to the adhesive surface and parallel to each other.

(Function) When an overvoltage is applied to the non-linear resistor and each block generates heat, each block is small, so it is easy to maintain a uniform temperature. Therefore, the occurrence of thermal stress is small, and the heat is dissipated. The heat is transmitted to the adjacent lumps via the adhesive having heat conductivity, and each lump is heated and expanded substantially uniformly, increasing the resistance of the bonded portion to thermal stress. Furthermore, even if there is a difference in the amount of expansion, the deviation is absorbed by the elasticity of the adhesive and does not cause a decrease in the overall durability.

Furthermore, if the non-linear resistor is formed as a whole into a substantially cylindrical shape, it can be made smaller in diameter compared to one made of a single piece with the same resistance, and if two parallel surfaces are provided that are substantially orthogonal to the bonding surface, They can be used on top of each other.

(Example) Hereinafter, an example embodying the present invention will be described in detail with reference to the drawings. As shown in Fig. 1, a non-linear resistor 1 installed in a lightning arrester etc. is formed into a columnar shape, and is divided into three equal parts into a fan-like shape along a line passing through the center and extending in the radial direction. It is composed of three lumps 2. Each block 2 is formed by sintering from a metal oxide material containing zinc oxide as a main component, and is bonded and fixed by an adhesive 3 having elasticity and heat conductivity on a pair of bonding surfaces 4 including the line segment. . As the adhesive 3, silicone rubber with high heat resistance and insulation properties, EPDM (ethylene-propylene-diene copolymer), highly elastic epoxy resin, etc. can be used. Further, the upper and lower surfaces 5, 6 of the non-linear resistor l perpendicular to the bonding surface 4 are polished smooth after bonding, and metallicon electrodes 7 are attached to the upper and lower surfaces 5,6.

Now, when manufacturing the above-mentioned non-linear resistor l, three fan-shaped blocks made of a material whose main component is zinc oxide, the angle θ between the pair of bonding surfaces 4 being set to 120 degrees, for example. 2 is sintered and formed. Next, the bonding surfaces 4 of each block 2 are fixed with adhesive 3 to form a non-linear resistor 1 having a cylindrical shape as a whole, and its upper and lower surfaces 5 and 6 are polished in parallel.

Further, when bonding each lump 2, a non-bonded portion 8 for positioning is formed at the outer peripheral end of each bonding surface 4. Then, while fixing the electrode 7 between each non-linear resistor 1, the non-adhesive portions 8 of each non-linear resistor 1 are fitted into the plurality of positioning pieces 9, so that the whole is formed into a vertically extending columnar shape. Once formed, a resistor unit for use in a lightning arrester, for example, can be manufactured.

It goes without saying that the operation start voltage ν1 mA of each lump must be kept within the required variation in order to evenly distribute the energy. And, the nonlinear resistor 1 of this embodiment
is composed of three fan-shaped blocks 2 having approximately the same volume, it is possible to secure the required electric energy withstand capacity that is approximately proportional to the number of each block, and the integral non-linear unit with the same volume Energy capacity is significantly increased compared to resistors. Furthermore, since the volume of each lump is smaller than that of an integral type, the thermal stress generated on itself is small, and the adhesive 3 has elasticity and heat conductivity.
When the amount of heat generated in a particular lump 2 increases due to the application of overvoltage, the heat is diffused to other lumps 2 through the adhesive 3, and the entire nonlinear resistor l is heated approximately evenly. This improves the properties against heat stress. Further, even if heat diffusion becomes uneven and a difference occurs in the amount of expansion of each block 2, the difference is absorbed by the elasticity of the adhesive.

Therefore, the resistance to thermal stress of the joint portions of the respective lumps 2 increases, and it is possible to prevent the non-linear resistor l from being destroyed from the joint portions of the lumps 2.

In addition, since each block 2 is formed into a fan plate shape and the nonlinear resistor l is formed into a columnar shape as a whole, the diameter can be made small, and the pair of surfaces 5. 6 are simultaneously polished in parallel to each other, a plurality of nonlinear resistors 1 can be used by stacking them on top of each other. Furthermore, each block 2 of the non-linear resistor 1 is provided with a non-bonded portion 8,
Since the portion 8 is used for positioning during overlapping, assembly can be easily performed.

Note that this invention is not limited to the above embodiments,
It is also possible to form the mass 2 into, for example, a semicircular shape, a quarter circle shape, or other fan plate shapes, or a disk shape or a square plate shape.

(Effects of the Invention) As detailed above, the present invention reduces the volume of each lump (by making the temperature rise inside each lump uniform, reducing internal stress and increasing the resistance to thermal stress of the joint part). In addition, it is possible to secure the required electric energy withstand capacity that is approximately proportional to the volume of each lump, and it also has the excellent effect of reducing the diameter and being able to be used by stacking them on top of each other. Demonstrate.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a non-linear resistor, and FIG. 2 is a plan view. DESCRIPTION OF SYMBOLS 1... Nonlinear resistor, 2... Mass, 3... Adhesive, 4... Adhesive surface, 5... Upper surface, 6... Lower surface.

Claims (1)

[Scope of Claims] A non-linear resistor characterized in that a plurality of lumps (2) containing zinc monoxide as a main component are adhesively fixed with an adhesive (3) having elasticity and heat conductivity. 2. The block (2) is formed into a fan-like shape, and the radially extending side surfaces (4) of the block are bonded to each other to form a substantially cylindrical shape as a whole. Non-linear resistor described in . 3. The mass (2) according to claim 1 or 2, wherein the mass (2) has two planes (5, 6) that are substantially orthogonal to the adhesive surface (4) and parallel to each other. Nonlinear resistor.