JP3932656B2 - Lightning arrestor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lightning arrester, and prevents the elements from making point contact even when the soot tube is bent.
[0002]
[Prior art]
The structure of a conventional lightning arrester is shown in FIG. In the figure, 1 is a jacket, 2 is a pipe, 3 is a cap, 4 is a presser plate, 5 is a support plate, 6 is a support rod for connecting a pair of support plates 5, 7 is a (zinc oxide) element, and 8 is Distance 9 is a spring.
[0003]
The lightning arrester is required to have bending strength (cantilever strength) which is mechanical strength. This is the strength when a load in a direction perpendicular to the axial direction of the lightning arrester is applied, so that the lightning arrester will not break even if it receives a load due to wind pressure, a load due to an earthquake, or a load of a lead wire connected to the lightning arrester. The purpose is to do.
[0004]
When a porcelain soot tube that constitutes a lightning arrester container is designed to withstand the above-mentioned load, the thickness of the material itself is set small due to the low strength of the material itself, resulting in increased rigidity against bending stress. Therefore, it was not necessary to consider the problem caused by the bending amount being reduced and the soot tube being bent.
[0005]
On the other hand, a polymer pipe using a polymer jacket as the jacket 1 shown in FIG. 4 and using FRP as the pipe 2 is being put into practical use. In the polymer pipe, the pipe 2 made of FRP having a high strength bears mechanical strength, while the jacket 1 made of polymer bears electrical insulation. Accordingly, the bending strength is determined by the thickness of the pipe 2. Since a pipe using FRP has a strength five times or more that of a porcelain porcelain pipe, it is possible to reduce the wall thickness against a predetermined bending load.
[0006]
[Problems to be solved by the invention]
However, when the pipe is thinned, when an external force is applied, the bending amount of the polymer rod tube is large as shown in FIG. For this reason, the elements 7 stacked as shown in FIG. 5A are in a state as shown in FIG. 5B, and the adjacent elements 7 are in point contact at the outer peripheral portion of the end surface. Therefore, a large load is applied to the small area of the device, causing damage and degrading the quality.
[0007]
On the other hand, the thickness of the pipe made of FRP may be increased to prevent bending, but a new problem arises that the cost increases and the weight increases.
[0008]
In addition, Japanese Utility Model Laid-Open No. 5-79820 discloses a lightning arrester in which a conductor having a smaller outer diameter than the resistive element is interposed between the laminated resistive elements. Since the current flows locally and on the resistance element, the resistance element is easily damaged by heat.
[0009]
Then, an object of this invention is to provide the lightning arrester which solved such a subject.
[0010]
[Means for Solving the Problems]
In order to achieve such an object, the structure of the lightning arrester according to claim 1 is a lightning arrester constructed by laminating elements inside a substantially cylindrical soot tube, and is connected between elements for each predetermined number of elements. The metal fitting is interposed, and the connection metal fitting is composed of a pair of support metal fittings that are in contact with substantially the entire end surfaces of a pair of opposing elements, and a sphere that is held in a substantially central portion of the pair of support metal fittings via a positioning portion. It is characterized by that.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the lightning arrester according to the present invention will be described below. In this embodiment, since a part of the conventional lightning arrester is improved, the same parts as those in the prior art are denoted by the same reference numerals and the description thereof is omitted, and only different parts will be described.
[0012]
(A) Embodiment 1
As shown in FIG. 1, a connection fitting 12 is provided between the elements 7 in the element 7 stacked between the upper and lower support plates 5. The number of connection fittings 12 is determined in accordance with the degree of bending deformation when a bending load is applied to the soot tube containing the element group of FIG. 1 in which the elements 7 are stacked, and is small when the bending amount is small. Many are provided when there are many. In the present embodiment, the connection fitting 12 is provided every time three elements 7 are stacked.
[0013]
Next, the structure of the connection fitting 12 will be described with reference to FIG. The connection fitting 12 includes a pair of support fittings 13 and a single sphere 14 held between the pair of support fittings 13. The support fitting 13 is formed at the center of the disc portion 13a for relative positioning between the disc portion 13a for supporting the device 7 by contacting the entire end surface of the device 7 and the sphere 14. The cylindrical portion 13b is a positioning portion whose inner diameter is slightly smaller than the outer diameter of the sphere 14.
[0014]
Next, the operation of such a lightning arrester will be described. In a state where no bending moment is applied to the arrester tube of the lightning arrester, the pair of support fittings 13 are substantially parallel as shown in FIG. 3A, and each of the support fittings 13 comes into contact with the entire end face of the element 7. A large force is not applied to a part of the element 7. The pair of support fittings 13 are electrically connected via a sphere 14.
[0015]
When the bending tube is deformed by applying a bending moment to the rod of the lightning arrester, the element group is deformed as shown in FIG. That is, the pair of support fittings 13 holding the sphere 14 are relatively rotated so that the two are not parallel. For this reason, when the portion where the three elements 7 are stacked is regarded as a straight line, the portion of the support fitting 13 is regarded as a bent portion, and a shape of a line graph is drawn along the arc, corresponding to the bent shape of the insulator. It will be. For this reason, a large local force does not act on a part of the element 7, and the element 7 is not damaged as in the prior art.
[0016]
(B) Embodiments 2 and 3
Next, Embodiments 2 and 3 will be described.
[0017]
In the second embodiment, a support metal fitting 13 having the shape shown in FIG. This is a cylindrical portion having a smaller inner and outer diameter than the cylindrical portion 13b of FIG. 2A, and a cylindrical portion 13c and a disc portion 13a as positioning portions whose upper end opening is widened by pressing the spherical body 14. The support metal fitting 13 is formed.
[0018]
In the third embodiment, the support fitting 13 having the shape shown in FIG. In this configuration, the connecting fitting 12 is configured by forming a spherical concave portion 13d having a depth shallower than the radial dimension of the spherical body 14 as a positioning portion at the center of the disk. The recess 13d is obtained by pressing the sphere 14 against the disc at a high pressure.
[0019]
When a lightning arrester is configured using the connection fitting 12 using the support fitting 13 shown in FIGS. 2B and 2C, the contact area between the sphere 14 and the support fitting 13 is large, so that the contact resistance is small. Further, since the locally applied pressure is smaller than in the case of FIG. 2A, it is mechanically stable.
[0020]
Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.
[0021]
In the present embodiment, the connection fitting is interposed for every three elements, but may be interposed every one, every two, or every four or more. In addition, the present embodiment applies the present invention to a lightning arrester using a polymer soot tube, but it may be a lightning arrester using a soot tube other than a polymer soot tube, and it may bend due to vibration during assembly or transportation. This prevents the device from being damaged.
[0022]
【The invention's effect】
As can be seen from the above description, according to the lightning arrester according to claim 1, since the connection fitting is interposed between the elements, when the insulator is bent, the connection fitting portion of the laminated element is bent. . Therefore, there is no tilting between the elements or between the element and the support metal fitting, and there is no contact between the elements and the entire surface comes into contact. For this reason, the outer peripheral portion of the end face of the element is not chipped and the reliability is high.
[0023]
In addition, since there is no point contact between elements as in the conventional case, surface contact is maintained, so that stable energization characteristics can be maintained, and thermal destruction of the element due to local current flow occurs. There is no.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a main part of a lightning arrester according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a connection fitting of first, second, and third embodiments of a lightning arrester according to the present invention.
FIG. 3 is an operation explanatory diagram of Embodiment 1 of the lightning arrester according to the present invention.
FIG. 4 is a cross-sectional view for explaining the configuration and operation of a conventional lightning arrester.
FIG. 5 is a diagram illustrating the operation of a conventional lightning arrester.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Outer jacket 2 ... Pipe 7 ... Element 12 ... Connection metal fitting 13 ... Support metal fitting 14 ... Sphere

Claims (1)

In a lightning arrester constructed by laminating elements inside a substantially cylindrical soot tube,
For each predetermined number of elements, a connection fitting is interposed between the elements. The connection fitting includes a pair of support fittings that contact substantially the entire end surfaces of a pair of opposing elements, and a pair of support fittings. A lightning arrester comprising a sphere held in the center via a positioning part.

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