JP2019153477A - Surge protective element - Google Patents

Abstract

To provide a surge protective element capable of suppressing degradation of life properties caused by metal vapor generated during discharge.SOLUTION: The surge protective element includes: an insulation tube; a pair of sealing electrode for closing openings at both ends of the insulation tube to seal discharge control gas; a planar insulation member 4 which is housed in the insulation tube and whose end parts 4b are in contact with the pair of sealing electrode; and a discharge auxiliary section 5 formed from conductive material in the center of the planar insulation member. The planar insulation member includes a groove part 4a formed, extending in such a direction as to cross an axial line of the insulation tube, between an end part of at least one surface and the discharge auxiliary section.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a surge protection element used for protecting various devices from a surge caused by a lightning strike and preventing accidents.

  Portions where electronic devices for communication equipment such as telephones, facsimiles, modems, etc. are connected to communication lines, power lines, antennas, CRT drive circuits, etc. A surge protection element is connected to the electronic device and a printed circuit board on which the device is mounted due to abnormal voltage to prevent destruction due to thermal damage or fire.

  Conventionally, as a surge protection element, for example, as shown in Patent Document 1, a glass tube, a pair of sealing electrodes that closes both ends of the glass tube and seals discharge gas inside, and a pair of seals at both ends. A surge absorber is described that includes a plate-like insulator provided with a stop electrode and housed in a glass tube. This surge absorber is a carbon trigger type surge protection element in which a carbon trigger portion, which is a conductive material, is formed at the center of the surface of the plate-like insulator.

JP 2010-192322 A

The following problems remain in the conventional technology.
In the conventional carbon trigger type surge protection element, when the inner diameter of the glass tube is reduced, the metal vapor generated from the sealing electrode during discharge tends to adhere to the surface of the plate-like insulator, and the repeated life characteristics deteriorate early. There was a problem. That is, the deterioration of the life characteristics is mainly due to the decrease of the discharge start voltage Vs, and the cause thereof is that the metal vapor generated during the discharge contaminates the insulating surface of the plate insulator. In particular, when attempting to reduce the size of the surge protection element by reducing the inner diameter of the glass tube, the metal vapor generated from the sealing electrode during discharge easily adheres to the surface of the plate-like insulator, and the life characteristics deteriorate early. There was an inconvenience.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a surge protection element that can suppress deterioration of life characteristics due to metal vapor generated during discharge.

  The present invention employs the following configuration in order to solve the above problems. That is, the surge protection element of the first invention includes an insulating tube, a pair of sealing electrodes that closes both ends of the insulating tube and seals the discharge control gas inside, and the insulating tube. A plate-like insulating member housed at both ends thereof in contact with the pair of sealing electrodes; and a discharge assisting portion formed of a conductive material at the center of the plate-like insulating member. However, it has a groove formed so as to extend in a direction crossing the axis of the insulating tube between the end of at least one surface and the auxiliary discharge portion.

  In this surge protection element, the plate-like insulating member is formed with a groove extending in a direction crossing the axis of the insulating tube between the end of at least one surface and the discharge auxiliary portion. The wall surface on the side close to the sealing electrode is behind the scattering direction of the scattered metal particles, so that it is difficult to be stained with metal, and the inner side (center side) of the groove can be prevented. In addition, it is difficult for the metal vapor to adhere to the inside of the groove portion, and the inside of the groove portion becomes a portion that is not easily contaminated with metal, so that insulation of the surface can be ensured. Therefore, a reduction in the discharge start voltage can be suppressed by forming a portion that is not soiled with metal on the inner surface of the groove portion of the plate-like insulating member.

According to a second aspect of the present invention, the surge protection element according to the first aspect is characterized in that the groove is formed on both surfaces of the plate-like insulating member.
That is, in this surge protection element, since the groove portion is formed on both surfaces of the plate-like insulating member, the effect of suppressing fouling by the groove portion can be obtained on both surfaces of the plate-like insulating member.

A surge protection element according to a third invention is characterized in that, in the first or second invention, the groove is formed over the entire width of the plate-like insulating member.
That is, in this surge protection element, since the groove portion is formed over the entire width of the plate-like insulating member, it is possible to obtain a fouling suppression effect by the groove portion over the entire width of the plate-like insulating member.

The surge protection device according to a fourth aspect of the present invention is the surge protection element according to any one of the first to third aspects, wherein the groove portion is formed between the end portion of the plate-like insulating member and the discharge auxiliary portion. A plurality of the sexual members are formed side by side in the length direction.
That is, in this surge protection element, a plurality of groove portions are formed side by side in the length direction of the plate-like insulating member between the end portion of the plate-like insulating member and the discharge assisting portion. Thus, a higher antifouling effect can be obtained.

The present invention has the following effects.
That is, according to the surge protection element of the present invention, the plate-like insulating member is formed with a groove portion extending in a direction crossing the axis of the insulating tube between the end portion of at least one surface and the discharge auxiliary portion. Therefore, it becomes difficult for the metal to adhere to the inner surface of the groove.
Therefore, in the surge protection device according to the present invention, a portion that is not soiled with metal is formed on the inner surface of the wall surface near the sealing electrode in the groove portion of the plate-like insulating member, so that the discharge start voltage is reduced. The decrease can be suppressed, and the deterioration of the life characteristics can be suppressed. In particular, the present invention is effective when the inner diameter of the insulating tube is reduced when the size is reduced, or when the distance between the end portion of the plate-like insulating member and the discharge auxiliary portion is shortened.

In 1st Embodiment of the surge protection element which concerns on this invention, it is a front view which shows the surge protection element when an insulating tube and a sealing electrode are fractured | ruptured. In 1st Embodiment, it is the top view (a) and AA sectional view (b) which show a plate-shaped insulating member. In 1st Embodiment, it is explanatory drawing which shows scattering of metal vapor | steam. In 2nd to 4th embodiment of the surge protection element which concerns on this invention, it is an expanded sectional view of the principal part which shows a groove part. In 5th Embodiment of the surge protection element which concerns on this invention, it is the top view (a) and BB sectional view (b) which show a plate-shaped insulating member.

  Hereinafter, a first embodiment of a surge protection element according to the present invention will be described with reference to FIGS. 1 to 3. In each drawing used for the following description, the scale is appropriately changed in order to make each member recognizable or easily recognizable.

  As shown in FIGS. 1 and 2, the surge protection element 1 of this embodiment includes a pair of seals that close the insulating tube 2 and both ends of the insulating tube 2 and seal the discharge control gas inside. The stop electrode 3, the plate-like insulating member 4 housed in the insulating tube 2 and having both end portions 4 b in contact with the pair of sealing electrodes 3, and a conductive material at the center of the plate-like insulating member 4 were formed. Discharge assisting unit 5 is provided.

The plate-like insulating member 4 has a groove portion 4 a formed between the end portion 4 b of at least one surface and the discharge auxiliary portion 5 so as to extend in a direction crossing the axis of the insulating tube 2. .
In this embodiment, the groove part 4a is formed in both surfaces of the plate-shaped insulating member 4, respectively. That is, two groove portions 4 a are formed on each side of the plate-like insulating member 4 and four on both sides.
Further, each groove 4 a is formed over the entire width of the plate-like insulating member 4.
Further, each groove 4a has a semicircular cross section as shown in FIG. In addition, the groove width of the groove part 4a is set to 0.1 mm, for example.

The said insulating tube 2 is a glass tube, for example, Comprising: It is comprised with soft glass like sealing glass or lead glass, soda-lime glass, and is cylindrical. Further, the outer peripheral surface of the sealing electrode 3 is welded to the inner peripheral surface of the insulating tube 2 in the vicinity of both ends of the insulating tube 2.
The sealing electrode 3 is a discharge electrode made of, for example, a metal in which the surface of an Fe (iron) -Ni (nickel) alloy is coated with copper oxide, and has a cylindrical shape. A lead wire 3 a is welded to the outer surface of the sealing electrode 3. The lead wire 3a is formed of a copper-clad steel wire or the like.

The plate-like insulating member 4 is an insulator formed in a plate shape with a ceramic material such as alumina or mullite sintered body.
Both ends 4b of the plate-like insulating member 4 are set wider than the center.
The discharge control gas is a sealing gas whose composition is adjusted so that electrical characteristics such as a discharge start voltage become a desired value, and is He, Ar, Ne, Xe, SF ₆ , CO ₂ , C _3. An inert gas such as F ₈ , C ₂ F ₆ , CF ₄ , H ₂ or a mixed gas thereof.

The discharge auxiliary portion 5 is a conductive material, for example, a carbon trigger formed of a carbon material.
The discharge assisting part 5 is formed in the center of the plate-like insulating member 4 in the shape of a rectangle or a short straight line along the axis.

  In the surge protection element 1 of this embodiment, when an overvoltage or overcurrent enters, initial discharge is first performed between the discharge assisting unit 5 and the sealing electrode 3. As a result of this initial discharge, the discharge further expands, and arc discharge is performed between the pair of sealing electrodes 3 that are discharge electrodes. This arc discharge progresses as shown in FIG. 3 from a portion where the end 4b of the plate-like insulating member 4 and the sealing electrode 3 are in contact with each other or in the vicinity thereof.

  Thus, like the surge protection element 1 of the present embodiment, the plate-like insulating member 4 is in a direction crossing the axis of the insulating tube 2 between the end portion 4b of at least one surface and the discharge auxiliary portion 5. Since the extended groove 4a is formed, the wall surface on the side close to the sealing electrode 3 in the groove 4a is behind the scattering direction of the scattered metal particles, so that it is not easily contaminated with metal, and the inner side (center) of the groove 4a. Side) can be prevented.

In addition, the metal vapor M hardly adheres to the inside of the groove portion 4a, and the groove portion 4a also becomes a portion that is not easily contaminated with metal, so that insulation of the surface can be ensured.
Therefore, a decrease in the discharge start voltage can be suppressed by forming a portion that is not soiled with metal on the inner surface of the groove 4a of the plate-like insulating member 4.
Moreover, since the groove part 4a is formed in both surfaces of the plate-shaped insulating member 4, the stain | pollution | contamination suppression effect by the groove part 4a can be acquired on both surfaces of the plate-shaped insulating member 4.
Furthermore, since the groove 4 a is formed over the entire width of the plate-like insulating member 4, the effect of suppressing fouling by the groove 4 a can be obtained over the entire width of the plate-like insulating member 4.

  Next, second to fifth embodiments of the surge protection element according to the present invention will be described below with reference to FIGS. In the following description of each embodiment, the same constituent elements described in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.

The difference between the second embodiment and the first embodiment is that the cross-sectional shape of the groove 4a is semicircular in the first embodiment, whereas the surge protection element of the second embodiment is shown in FIG. As shown to a), the groove part 24a of the plate-shaped insulating member 24 is a point which has V-shaped cross-sectional shape.
Moreover, in the surge protection element of 3rd Embodiment, as shown in FIG.4 (b), the groove part 34a of the plate-shaped insulating member 34 has a rectangular cross-sectional shape.
Moreover, in the surge protection element of 4th Embodiment, as shown in FIG.4 (c), the groove part 44a of the plate-shaped insulating member 44 is from the wall part perpendicular | vertical with respect to the surface, and the bottom face of cross-sectional arc shape. It has a cross-sectional shape.

In the surge protection elements of the second to fourth embodiments, as in the first embodiment, the metal vapor M is contaminated by the grooves 24a, 34a, and 44a interposed in the middle from the end 4b to the discharge auxiliary portion 5. An inhibitory effect can be obtained.
Note that the deeper the groove portions 24a, 34a, and 44a, the greater the effect of suppressing the contamination of the metal vapor M.

  Next, the difference between the fifth embodiment and the first embodiment is that, in the first embodiment, one groove portion 4 a is provided between each end portion 4 b of the plate-like insulating member 4 and the discharge auxiliary portion 5. On the other hand, in the surge protection element of the fifth embodiment, as shown in FIG. 5, the groove 4 a has a plate-like insulation between the end 4 b of the plate-like insulating member 54 and the discharge auxiliary portion 5. It is a point that a plurality of the sexual members 54 are formed side by side in the length direction.

That is, in the fifth embodiment, two groove portions 4 a are formed between each end portion 4 b of the plate-like insulating member 54 and the discharge auxiliary portion 5. Therefore, four groove portions 4a are formed on one surface of the plate-like insulating member 54, and four grooves are formed on the other surface.
As described above, in the surge protection element according to the fifth embodiment, a plurality of groove portions 4 a are arranged in the length direction of the plate-like insulating member 54 between the end portion 4 b of the plate-like insulating member 54 and the discharge auxiliary portion 5. Since it is formed, a higher antifouling effect can be obtained by the plurality of grooves 4a.

  The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Surge protection element, 2 ... Insulating tube, 3 ... Sealing electrode, 4,54 ... Plate-like insulating member, 4a ... Groove part, 4b ... End part of plate-like insulating member, 5 ... Discharge auxiliary part

Claims (4)

An insulating tube;
A pair of sealing electrodes for closing the opening at both ends of the insulating tube and sealing the discharge control gas inside;
A plate-like insulating member housed in the insulating tube and having both ends in contact with the pair of sealing electrodes;
A discharge auxiliary portion formed of a conductive material in the center of the plate-like insulating member,
The plate-like insulating member has a groove formed so as to extend in a direction crossing the axis of the insulating tube between the end of at least one surface and the discharge auxiliary portion. Surge protective element. The surge protection element according to claim 1,
The surge protection element, wherein the groove is formed on both surfaces of the plate-like insulating member. The surge protection element according to claim 1 or 2,
The surge protection element, wherein the groove is formed over the entire width of the plate-like insulating member. In the surge protection element according to any one of claims 1 to 3,
A surge protection element, wherein a plurality of the groove portions are formed side by side in the length direction of the plate-like insulating member between the end portion of the plate-like insulating member and the discharge auxiliary portion.

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