JP4896316B2 - Gas-sealed lightning arrester - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of a gas-sealed lightning arrester formed by sealing an inert gas.
[0002]
[Prior art]
Today, gas-sealed lightning arresters (hereinafter referred to as lightning arresters) connected for power supply and communication are frequently used because of their good discharge characteristics and long life. However, this gas-sealed lightning arrester is a big problem because it may contaminate the inner peripheral edge of the insulation envelope due to sputtering by the evaporated metal, resulting in a decrease in insulation and a decrease in discharge characteristics. It was.
[0003]
For this reason, when joining the opposing electrode and the insulating envelope through the insulating envelope, for example, metallization is performed on the opening of the insulating envelope, and the brazing material is melted on the bonding surface with the electrode. It was made to seal. In this case, molybdenum or dungsten, which is a high melting point metal, is often used as an electrode material in order to prevent damage to the electrode (see Japanese Patent Application Laid-Open No. 8-96924). Even if the brazing material was melted on the surface, it was difficult to firmly join the joint surfaces.
[0004]
In addition, when the brazing material is melted and fixed between the sealing surface and the discharge surface of the electrode protruding from the joining surface into the insulating envelope, the brazing material has a great affinity. As a result, the molten brazing material flows into substantially the entire discharge surface to form a thin film. For this reason, as the brazing material, silver brazing that does not contain Zn or the like that is easily sputtered has been used. Although Ag is not as much as Zn, it has a tendency to be sputtered, and the thin film contains a large amount of Ag and is likely to be sputter-contaminated.
[0005]
[Problems to be solved by the invention]
The present invention has been made in response to the above circumstances, and an object of the present invention is to provide a gas-sealed lightning arrester that is less likely to cause contamination of the inner peripheral edge of an insulating envelope due to sputtering and can maintain high discharge characteristics. .
[0006]
It is another object of the present invention to provide a novel gas-sealed lightning arrester capable of firmly joining an insulating envelope and an electrode and sealing gas reliably.
[0007]
[Means for Solving the Problems]
In consideration of the above-described problems, the gas-sealed lightning arrester of the present invention employs the following means.
[0008]
That is, according to the first aspect of the present invention, in the gas-sealed lightning arrester formed by gas-sealing between electrodes separated through a cylindrical insulating envelope, male and female screws are respectively provided on the electrode and the insulating envelope. The gas is sealed by screwing the male screw and the female screw.
[0009]
In this means, male and female screws are screwed together, and an electrode is assembled to the insulating envelope, and the gas is sealed.
[0010]
According to a second aspect of the present invention, in the gas-sealed lightning arrester according to the first aspect, a male screw is provided on the outer peripheral edge of the electrode and a female screw is provided on the inner peripheral edge of the insulating envelope. It is characterized by being provided in large numbers.
[0011]
In this means, a male screw is provided on the outer peripheral edge of the electrode, and the male screw of the electrode is screwed to the female screw on the inner peripheral edge of the insulating envelope, thereby sealing the gas. Further, in the inner circumference of the insulating envelope, the inner groove distance of the insulating envelope is set to be long by the thread groove of the female screw in which the electrode is not screwed, and the portion which is shaded with respect to the sputtering direction of the evaporated metal is It is formed.
[0012]
According to a third aspect of the present invention, in the gas-sealed lightning arrester according to the first or second aspect, the electrode has a flange portion joined to the open end face of the insulating envelope.
[0013]
In this means, the flange portion of the electrode and the opening end surface of the insulating envelope form a circumferential joint surface by screw tightening, and the gas is sealed over the circumferential shape.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment (1) of the gas-sealed lightning arrester of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view for explaining the structure of the gas-sealed lightning arrester of the embodiment (1), and FIG. 2 is an enlarged perspective view showing a longitudinal section of the gas-sealed lightning arrester of the embodiment (1). In the embodiment (1), a case where a male screw is provided on the outer peripheral edge of the electrode and a female screw is provided on the inner peripheral edge of the insulating envelope will be described.
[0015]
As shown in FIG. 1, the lightning arrester 1 has an inert envelope such as argon inside the electrodes 2 and 4 and the insulating envelope 3 that are separated by a cylindrical insulating envelope 3 made of ceramic or the like. In this structure, the gas is sealed and discharge is obtained at the discharge gap 23 between the discharge surfaces 212 and 412 facing each other.
[0016]
The electrodes 2 and 4 are metal electrodes and are composed of male screws 21 and 41 and electrode portions 22 and 42. Male screws 21 and 41 provided on the outer peripheral edges of the electrodes 2 and 4, and electrode portions 22 and 42 each having a button shape are connected to the end of the male screw.
[0017]
The male screws 21 and 41 are formed of screw threads 211 and 411 having at least three pitches. The outer diameters of the threads 211 and 411 are set to such an extent that they can be smoothly screwed into the inner wall 33 of the insulating envelope 3. Moreover, the discharge surfaces 212 and 412 which are the front-end | tip parts of the external threads 21 and 41 are formed substantially flat to such an extent that discharge can be performed when the electrodes 2 and 4 are screwed in the inner direction of the insulating envelope 3.
[0018]
The electrode portions 22 and 42 having a button shape are composed of flange portions 221 and 421 connected to the above-described male screws 21 and 41 and electrode surfaces 222 and 422 connected to the communication line side or the ground side. The outer diameters of the electrode portions 22 and 42 are larger than the outer diameter of the male screws 21 and 41 and are set to be approximately the same diameter as the outer peripheral edge of the insulating envelope 3.
[0019]
The flange portions 221 and 421 have a flat bowl shape. The circumferential width between the outer peripheral edge and the inner peripheral edge of the insulating envelope 3, that is, approximately the same width as the circumferential width of the opening end surface 32 described later. The surfaces of the flange portions 221 and 421 are formed as smooth surfaces that can seal the gas. Specifically, the average surface roughness is preferably about 0.1a to 0.5a.
[0020]
The insulated envelope 3 is formed with female threads 31 along the peripheral surface of the inner wall 33, and ring-shaped open end faces 32 are formed at the upper and lower ends of the insulated envelope 3. The surface of the open end surface 32 is configured to be a smooth surface that can be in close contact with the flange portions 221 and 421 and seal the gas. Specifically, like the flange portions 221 and 421, the average surface roughness is preferably about 0.1a to 0.5a. The circumferential width of the opening end face 32 is a joining distance W when the flange portions 221 and 421 and the opening end face 32 are joined. This joining distance W is sufficient to secure a sufficient distance and forms a sealing region for reliably preventing gas leakage.
[0021]
The female screw 31 has a thread 311 having at least three pitches or more formed on the peripheral surface of the inner wall 33 of the insulating envelope 3 and has a thread number of at least one pitch more than the threads 211 and 411 of the male screws 21 and 41. Is provided. When a discharge occurs between the discharge surfaces 212 and 412, a metal piece due to sputtering scatters in a certain direction. At this time, as shown in FIG. 2, only one screw surface 315 of the extra screw thread 314 is scattered. A metal piece adheres and does not adhere to the other threaded surface 316. In addition, metal pieces are less likely to collect in the screw groove 317. This prevents a short circuit between the discharge surfaces 212 and 412 due to spatter contamination. Furthermore, the insulating envelope 3 using the ceramic material is somewhat shrunk in the heat of sintering when forming the insulating envelope 3 compared to the electrodes 2 and 4 using the metal material. However, since an extra thread 314 is provided, shrinkage errors that may occur during sintering of the female thread 31 are absorbed.
[0022]
Next, the manufacturing process of the lightning arrester 1 will be described.
[0023]
At the time of manufacture, the male screws 21 and 41 formed on the electrodes 2 and 4 are assembled by screwing them from the upper and lower opening ends of the insulating envelope 3. The male screws 21 and 41 that have started to be screwed are screwed into the female screw 31 formed on the inner wall 33 of the insulating envelope 3. When the male screws 21 and 41 are screwed into the insulating envelope 3, a tightening force is generated in the insulating envelope 3 by the screwing of the male and female screws. Since this tightening force acts in the axial direction, contact portions between the male screw 21 and the female screw 31 on the axial direction side, that is, as shown in FIG. . Thereby, the electrodes 2 and 4 and the insulation envelope 3 are fitted. When the screwing of the male screws 21 and 41 is completed, the flange portions 221 and 421 of the electrodes 2 and 4 and the opening end surface 32 of the insulating envelope 3 are joined. Bonding surfaces 5 and 6 with high adhesion are formed, and a gas sealing region is secured.
[0024]
At the same time, an inert gas such as argon is enclosed in the insulating envelope 3. Even if the inert gas is sealed, the screw surfaces 213 and 313 of the male screw 21 and the female screw 31 on the axial direction side are in close contact with each other, and the flange portions 221 and 421 and the open end surface 32 are sealed by the joint surfaces 5 and 6. Stopped. That is, gas leakage is firmly prevented in two stages, the inner wall 33 of the insulating envelope 3 and the upper and lower opening ends. Furthermore, the joining surfaces 5 and 6 are joined along the circumferential shape of the lightning arrester 1 while having a sufficient joining distance W. Therefore, since the lightning arrester 1 has a sufficient gas sealing region over the circumference, even if the enclosed gas leaks to the joint surfaces 5 and 6, it leaks to the outside through the sufficient sealing region. There is no.
[0025]
When the joining surfaces 5 and 6 are formed, the discharge gap 23 is formed between the discharge surfaces 212 and 412 at the tip of the screw screwed into the insulating envelope 3, and the gap length G is fixed. Since the excess thread 314 is formed as described above, the gap length G can be set easily and freely to such an extent that discharge can be performed. Therefore, the gap length G can be easily controlled. The lightning arrester 1 is completed by the above manufacturing process.
[0026]
Embodiment (2) of this invention is demonstrated based on drawing. In the embodiment (2), a case where a female screw is provided on the electrode and a male screw is provided on the insulating envelope is applied, which will be described below. FIG. 3 is an enlarged longitudinal sectional view of the gas-sealed lightning arrester of the embodiment (2).
[0027]
The electrodes 2 and 4 are provided with female screws 25 and 45 on the inner peripheral edge thereof, and have a shape capable of screwing the outer peripheral edge of the insulating envelope 3 to be described later. It is a lid-shaped shape that covers the upper and lower opening ends of the envelope 3. Projections 24 and 44 are connected to the center of the electrodes 2 and 4, and are formed into shapes that can be inserted into the opening of the insulating envelope 3, for example, cylindrical projections 24 and 44. Furthermore, the electrodes 2 and 4 have electrode surfaces 222 and 422 connected to the communication line side or the ground side. The outer diameters of the electrode surfaces 222 and 422 are set larger than the outer diameter of the insulating envelope 3.
[0028]
The female threads 25 and 45 are formed with screw threads 251 and 451 having at least 3 pitches on the inner wall 26 of the lid electrodes 2 and 4, and screw threads 351 of the male threads 35 provided on the outer peripheral edge of the insulating envelope 3. There are few mountains.
[0029]
The cylindrical projecting pieces 24 and 44 are provided with a diameter smaller than the diameter of the inner wall 33 of the insulating envelope 3. Thus, when the projecting pieces 24 and 44 are inserted from the upper and lower opening ends toward the inside of the insulating envelope 3, the joining surfaces 5 and 6 having the joining distance W are formed, and the insulating envelope 3 and the projecting piece 24 are formed. , 44, a gap g is formed so as to penetrate the inside of the insulating envelope 3 vertically. Further, the end portions of the projecting pieces 24 and 44 are discharge surfaces 212 and 412.
[0030]
The insulated envelope 3 is formed with a male screw 35 along the outer peripheral edge. The circumferential width of the opening end surface 32 having a smooth surface is a bonding distance W when the back surfaces of the electrodes 2 and 4 are bonded to the opening end surface 32 to form the bonding surfaces 5 and 6. As in the case of the embodiment (1), by providing the bonding distance W with a sufficient length, a sealing region is secured.
[0031]
The male screw 35 has at least three or more screw threads 351 formed on the outer peripheral edge of the insulating envelope 3, and has more screw threads than the screw threads 251 and 451 of the female screws 25 and 45, and an extra screw thread 314 is provided. . Since this effect is the same as that of Embodiment (1), it is omitted.
[0032]
At the time of manufacture, the lightning arrester 1 is completed by screwing the female screws 25 and 45 formed on the electrodes 2 and 4 with the male screw 35 of the insulating envelope 3.
[0033]
As described above, the gap g prevents a short circuit due to sputtering that occurs when a discharge is performed between the discharge surfaces 212 and 412 as in the first embodiment. That is, even when a metal piece adheres to the inner wall 33 of the insulating envelope 3 near the discharge due to sputtering, the metal piece is far from the back side of the electrodes 2 and 4 along the inner wall 33 and is difficult to reach. This is because the metal pieces that cause a short circuit are not accumulated. With the above structure, the life of the lightning arrester 1 can be extended.
[0034]
【Example】
The male screws 21 and 41 were made of a high melting point metal electrode such as dungsten, molybdenum, or a material composed of these alloys. In addition, a first-class male screw having a thread of at least 3 pitches was used, and for example, M6, a pitch of 1 mm, and an outer diameter of 6 mm could be formed. The electrode portions 22 and 42 having a button shape are made of aluminum, a metal widely used as a conductive material having a diameter of about 10 mm. As the insulating envelope 3, an alumina (Al ₂ O ₃ ) envelope having a diameter of about 10 mm was used. The width W of the joining surfaces 5 and 6 was set to about 1.5 mm, and the sealing region was set to occupy about half of the envelope area. The finished surfaces of the flange portions 221 and 421 and the opening end surface 32 forming the joint surfaces 5 and 6 have an average roughness Ra = 0.2a.
[0035]
As a result of sintering the electrode and the alumina envelope with this material, both male and female screws could be easily formed.
[0036]
Further, since the gas was sealed inside the alumina envelope by forming the male and female threads and forming the joint surface, it was possible to reliably discharge inside the alumina envelope.
[0037]
Furthermore, no short circuit occurred due to continuous use of the discharge time, and no gas leakage was confirmed.
[0038]
[Effect of the present invention]
As described above in detail, the gas-sealed lightning arrester according to the present invention is formed by screwing male and female screws and forming a joining surface for joining the electrode and the insulating envelope, thereby providing a conventional method such as silver brazing. There is no need to seal the gas by using it, and it has an excellent effect of being a gas-sealed lightning arrester that can be reliably sealed and easily formed.
[0039]
In addition, by providing an extra screw thread in the insulation envelope during manufacturing, shrinkage due to sintering can be absorbed, and contamination inside the insulation envelope due to sputtering during discharge can be prevented, resulting in reduced insulation. In addition, it has an excellent effect of suppressing the occurrence of defects.
[0040]
Furthermore, since the gap length between the discharge surfaces can be controlled by screw formation, there is an excellent effect that the operating voltage of the gas-sealed lightning arrester can be easily controlled.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating the structure of a gas-sealed lightning arrester according to an embodiment (1).
FIG. 2 is an enlarged perspective view showing a longitudinal section of the gas-sealed lightning arrester of the embodiment (1).
FIG. 3 is an enlarged longitudinal sectional view of a gas-sealed lightning arrester according to Embodiment (2).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lightning arrester 2, 4 Electrode 21, 41, 35 Male thread 211, 411, 351 Male screw thread 212, 412 Discharge surface 213 Male screw thread surface 22, 42 Electrode part 221, 421 Flange part 222, 422 Electrode surface 23 Discharge gap 24 44 Projection piece 3 Insulation envelope 31, 25, 45 Female thread 311, 251, 451 Female thread thread 313, 315, 316 Female thread thread surface 314 Extra thread thread 317 Screw groove 32 Open end surface 33, 26 Inner wall 5, 6 Joining surface W Joining distance G Gap length g Gap

Claims (4)

In a gas-sealed lightning arrester formed by gas-sealing between electrodes separated via a cylindrical insulating envelope, a male screw and a female screw are provided on the electrode and the insulating envelope, respectively. The gas is sealed by screwing assembly,
The opening end surface of the insulating envelope has a predetermined circumferential width for preventing gas leakage,
The electrode has a joint surface that joins the opening end surface of the insulating envelope when the male screw and the female screw are screwed together.
In order to seal the gas, an average roughness Ra of the opening end face of the insulating envelope and the joint surface of the electrode is 0.1a to 0.5a.   The gas-sealed lightning arrester according to claim 1, wherein a male screw is provided on the outer peripheral edge of the electrode and a female screw is provided on the inner peripheral edge of the insulating envelope, and the number of threads of the female screw is greater than the number of threads of the male screw. A gas-sealed lightning arrester.   3. The gas-sealed lightning arrester according to claim 1 or 2, wherein the electrode has a flange portion joined to the opening end face of the insulating envelope.   2. The gas-sealed lightning arrester according to claim 1, wherein a male screw is provided on the insulating outer edge, and the electrode is screwed into a male screw of the insulating envelope, and an open end of the cylindrical insulating envelope. A projecting piece that is inserted in the central portion from the opening end toward the inside of the insulating envelope, and a terminal portion of the projecting piece serves as a discharge surface. Gas-sealed lightning arrester.

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