JP2018056024A - Serge protection element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a serge protection element capable of preventing discharge auxiliary part from contacting a brazing material and positioning an insulating pipe and a projection electrode part.SOLUTION: A serge protection element comprises: a square cylindrical insulating pipe 2; a pair of sealing electrodes 3 for blocking both end openings of the insulating pipe to seal a discharge control gas in the inside; and a discharge auxiliary part 4 formed of an ion source material except the vicinities of corner portions 2a in the inner peripheral surface of the insulating pipe. The pair of sealing electrodes comprises: a pair of flange parts 5 fixed to both end openings of the insulating pipe in a close contact state; a pair of projection electrode parts 6 projecting inward from the pair of flange parts and facing each other; and a plurality of positioning projections 7 projecting inward from the pair of flange parts and arranged in the vicinity of at least two facing corner portions in the inner peripheral surface of the insulating pipe.SELECTED DRAWING: Figure 1

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.

  Abnormal voltage (such as lightning surge or static electricity) on the part where electronic devices for communication devices such as telephones, facsimiles, modems, etc. are connected to communication lines, power lines, antennas or image display drive circuits such as CRTs, liquid crystal televisions and plasma televisions. A surge protection element is connected to a portion that is easily subjected to electric shock due to a surge voltage) in order to prevent destruction due to abnormal damage due to thermal damage or ignition of an electronic device or a printed circuit board on which the device is mounted.

  Conventionally, as shown in Patent Documents 1 and 2, for example, an arrester type comprising a pair of protruding electrode portions protruding in a facing state from a pair of sealing electrodes, and having a discharge auxiliary portion formed on the inner peripheral surface of the insulating tube A surge protection element is described. Usually, in such a surge protection element, a discharge auxiliary portion made of a carbon material is formed on the inner peripheral surface of the insulating tube. Such a discharge auxiliary portion is generally formed of a conductive ion source material such as graphite and serves as an ion source for promoting initial discharge. Further, in such a surge protection element, in order to position the insulating tube and the protruding electrode portion, a diameter-enlarged portion having a diameter larger than that of the distal end portion is provided on the proximal end side of the protruding electrode portion. .

JP 11-354244 A JP 2001-102148 A

The following problems remain in the conventional technology.
In the conventional structure, when the discharge auxiliary part is extended to the vicinity of the enlarged diameter part of the protruding electrode part, if the discharge auxiliary part interferes with the enlarged diameter part of the protruding electrode part, the discharge voltage decreases and the DC discharge start voltage There was a case where it fluctuated. In particular, when producing a low-voltage product, in order to stabilize the discharge start voltage Vs, it is necessary to form the discharge auxiliary portion as long as possible along the axial direction on the inner peripheral surface of the insulating tube. It becomes easy to come into contact with the enlarged diameter portion, and it becomes difficult to start discharge stably with the tip end side of the protruding electrode portion. Also, when the sealing electrode is fixed to the insulating tube with the brazing material, the brazing material swells on the inner surface of the insulating tube along the enlarged diameter portion, and discharges at an abnormally low voltage by interfering with the discharge assisting portion. 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 capable of preventing contact between the discharge auxiliary portion and the brazing material and positioning the insulating tube and the protruding electrode portion. To do.

  The present invention employs the following configuration in order to solve the above problems. That is, the surge protection element according to the first invention includes a rectangular tube-shaped insulating tube, a pair of sealing electrodes that closes both ends of the insulating tube and seals the discharge control gas therein, A discharge auxiliary portion formed of an ion source material in addition to the inner peripheral surface of the insulating tube and in the vicinity of a corner portion of the inner peripheral surface, and the pair of sealing electrodes are provided at both ends of the insulating tube. A pair of flange portions fixed in close contact with the opening, a pair of projecting electrode portions projecting inwardly from the pair of flange portions and facing each other, and projecting inwardly from the pair of flange portions and the insulating tube And a plurality of positioning projections arranged in the vicinity of two corners facing each other at least on the diagonal line on the inner peripheral surface of the.

  In this surge protection element, the sealing electrode has a plurality of positioning projections that protrude inward from the pair of flange portions and are arranged in the vicinity of at least two opposing corners on the inner peripheral surface of the insulating tube. As a result, the insulating tube and the sealing electrode can be positioned by the positioning protrusions, and the absence of the discharge auxiliary portion near the corner portion prevents contact between the discharge auxiliary portion and the brazing material. it can. That is, when the insulating tube and the sealing electrode are bonded with the brazing material, the brazing material interferes with the discharge assisting portion because there is no discharge assisting portion in the vicinity even if the brazing material runs up on the positioning projection. And a stable discharge voltage can be maintained.

The surge protection element according to a second invention is characterized in that, in the first invention, the positioning projections are provided in the vicinity of four corners on the inner peripheral surface of the insulating tube. .
That is, in this surge protection element, since the positioning protrusions are provided in the vicinity of the four corners on the inner peripheral surface of the insulating tube, the positioning protrusions near the four corners of the inner peripheral surface It is possible to position with higher accuracy.

The surge protection element according to a third aspect of the present invention is characterized in that, in the first or second aspect, the outer periphery of the positioning projection is formed smaller toward the tip.
That is, in this surge protection element, since the outer periphery of the positioning projection is made smaller toward the distal end, the distance from the inner peripheral surface of the insulating tube is increased toward the distal end, and the brazing material is less likely to run up.
In the case of a rod-shaped positioning projection, the shape cannot be obtained with high accuracy due to deterioration of the mold when a sealing electrode is produced by cold forging, and the required protruding height cannot be obtained. There is. However, by using a positioning projection with a smaller outer periphery at the tip, it is possible to alleviate the deterioration of the mold when the sealing electrode is produced by cold forging compared to a rod-shaped positioning projection. In production, a stable shape can be obtained.

A surge protection element according to a fourth invention is characterized in that, in any one of the first to third inventions, the positioning projection extends from the protruding electrode portion to the vicinity of the corner portion. To do.
That is, in this surge protection element, since the positioning projection extends from the protruding electrode portion to the vicinity of the corner portion, the deterioration of the mold can be reduced as compared with the rod-shaped positioning projection, In production, a stable shape can be obtained.

The present invention has the following effects.
That is, according to the surge protection element according to the present invention, the sealing electrode protrudes inward from the pair of flange portions and has a plurality of portions disposed in the vicinity of at least two opposing corner portions on the inner peripheral surface of the insulating tube. Since the positioning projections are provided, the insulating tube and the sealing electrode can be positioned by the positioning projections, and contact between the discharge auxiliary portion and the brazing material can be prevented.
Therefore, positioning can be performed with high accuracy and a stable discharge voltage can be maintained.

In 1st Embodiment of the surge protection element which concerns on this invention, it is a perspective view which shows an inside with a broken line. In 1st Embodiment, it is a longitudinal cross-sectional view which shows the sealing electrode adhere | attached on the insulating pipe | tube. In 1st Embodiment, it is a top view which shows the sealing electrode. In 2nd Embodiment of the surge protection element which concerns on this invention, it is a top view which shows a sealing electrode. FIG. 5 is a cross-sectional view taken along line AA in FIG. 4. In 3rd Embodiment of the surge protection element which concerns on this invention, it is a top view which shows a sealing electrode. FIG. 7 is a cross-sectional view taken along line B-B in FIG. 6.

  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 FIG. 1 to FIG. 3, the surge protection element 1 of the present embodiment closes the rectangular tube-shaped insulating tube 2 and both ends of the insulating tube 2 and seals the discharge control gas inside. And a discharge auxiliary portion 4 formed of an ion source material in addition to the vicinity of the corner portion 2a of the inner peripheral surface, which is the inner peripheral surface of the insulating tube 2.

The pair of sealing electrodes 3 includes a pair of flange portions 5 fixed in close contact with both end openings of the insulating tube 2 and a pair of projecting electrode portions protruding inward from the pair of flange portions 5 and facing each other. 6 and a plurality of positioning projections 7 projecting inwardly from the pair of flange portions 5 and disposed in the vicinity of at least two opposing corner portions 2a on the inner peripheral surface of the insulating tube 2.
In the present embodiment, positioning protrusions 7 are provided in the vicinity of the four corners 2 a on the inner peripheral surface of the insulating tube 2. That is, the positioning projections 7 are provided at the four corners on the inner peripheral surface of the insulating tube 2, and each positioning projection 7 is in contact with the inner peripheral surface of the insulating tube 2 near the corner 2a. ing.

The discharge auxiliary portion 4 is formed linearly along the axis at the center of a pair of inner surfaces facing each other of the insulating tube 2. That is, the discharge auxiliary part 4 is arranged at an intermediate position between the adjacent corners 2a.
The discharge auxiliary portion 4 is a conductive material, and is formed of, for example, a carbon material.
The insulating tube 2 is a square cylindrical member formed of a crystalline ceramic material such as alumina. The insulating tube 2 may be an amorphous tube such as lead glass.

The sealing electrode 3 is made of, for example, 42 alloy (Fe: 58 wt%, Ni: 42 wt%), Cu, or the like.
The sealing electrode 3 has a square plate-like flange portion 5 that is fixed in a close contact state by heat treatment with a conductive adhesive (not shown) at both ends of the insulating tube 2. The flange portion 5, the protruding electrode portion 6 and the positioning projection portion 7 are provided integrally.

The conductive fusing material is formed of, for example, an Ag—Cu brazing material as a brazing material containing Ag.
The discharge control gas sealed in the insulating tube 2 is an inert gas or the like, for example, He, Ar, Ne, Xe, Kr, SF ₆ , CO ₂ , C ₃ F ₈ , C ₂ F ₆ , CF ₄ , H ₂ , air, etc. and mixed gas thereof are used.

A discharge active layer (not shown) is formed on the tip surface of the protruding electrode portion 6 with a material having higher electron emission characteristics than the material of the sealing electrode 3.
The discharge active layer includes, for example, Si and O as main components and includes at least one of Na, Cs, and C. For this discharge active layer, for example, a cesium carbonate powder is added to a sodium silicate solution to prepare a precursor, and after this precursor is applied to the surface of the sealing electrode 3, the sodium silicate is softened to the precursor. It is produced by performing a heat treatment at a temperature higher than the temperature and higher than the temperature at which cesium carbonate melts and decomposes.

The positioning protrusion 7 is formed in a columnar shape lower than the protruding electrode portion 6.
The sealing electrode 3 is manufactured by cold forging using a mold, and the positioning projection 7 is integrally formed together with the protruding electrode 6 and the flange 5.

  In this surge protection element 1, when overvoltage or overcurrent enters, first, initial discharge is preferentially performed between the discharge auxiliary portion 4 and the protruding electrode portion 6, and the discharge further develops triggered by this initial discharge. Thus, discharge is performed between the pair of flange portions 5 or between the protruding electrode portions 6.

As described above, in the surge protection device 1 of the present embodiment, the sealing electrode 3 protrudes inward from the pair of flange portions 5 and is disposed in the vicinity of at least two opposing corner portions 2 a on the inner peripheral surface of the insulating tube 2. Since the plurality of positioning projections 7 are provided, the insulating tube 2 and the sealing electrode 3 can be positioned by the positioning projections 7.
In particular, since the positioning protrusions 7 are provided in the vicinity of the four corners 2a on the inner peripheral surface of the insulating tube 2, the positioning protrusions 7 near the four corners of the inner peripheral surface Positioning can be performed with high accuracy.

Further, since there is no discharge auxiliary portion 4 in the vicinity of the corner portion 2a, contact between the discharge auxiliary portion 4 and the brazing material can be prevented.
That is, when the insulating tube 2 and the sealing electrode 3 are bonded to each other with a brazing material, even if the brazing material runs up on the positioning projection 7, there is no discharge auxiliary portion 4 in the vicinity. A stable discharge voltage can be maintained without interfering with the portion 4.

  Next, second and third 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, in the first embodiment, the positioning projection 7 is formed in a cylindrical shape, whereas in the surge protection element of the second embodiment, FIG. As shown in FIG. 5 and FIG. 5, the positioning projection 27 has a smaller outer periphery at the tip.
That is, in the second embodiment, as shown in FIG. 4, a positioning projection 27 having a semicircular outer side and a substantially V-shaped inner side in a plan view is employed. The projecting portion 27 has a mountain shape as a whole. These positioning projections 27 have a teardrop shape from the corner 2a toward the center of the flange 5.

As described above, in the surge protection element according to the second embodiment, the positioning projection 27 of the sealing electrode 23 is formed such that the outer periphery is smaller toward the tip, so that the distance from the inner peripheral surface of the insulating tube 2 is closer to the tip. It is difficult to spread the brazing material.
In the case of the rod-shaped positioning projection as in the first embodiment, the shape cannot be obtained with high accuracy due to deterioration of the mold when the sealing electrode is produced by cold forging, and the required protrusion height You may not be able to get it. However, by using the positioning protrusion 27 whose outer periphery is smaller toward the tip, the deterioration of the mold can be alleviated when the sealing electrode 23 is produced by cold forging compared to the case of the rod-shaped positioning protrusion. In production, a stable shape can be obtained.

Next, the difference between the third embodiment and the second embodiment is that, in the second embodiment, the positioning projection 27 extends partway from the corner 2a toward the protruding electrode portion 6. In the surge protection element of the third embodiment, as shown in FIGS. 6 and 7, the positioning projection 37 extends from the protruding electrode 6 to the vicinity of the corner 2 a.
That is, in the third embodiment, as shown in FIG. 6, four positioning projections 37 are formed to extend from the protruding electrode portion 6 to the four corners in four directions.

  As described above, in the surge protection element of the third embodiment, the positioning projection 37 of the sealing electrode 33 extends from the protruding electrode 6 to the vicinity of the corner 2a. Compared with this, deterioration of the mold can be alleviated, and a stable shape can be obtained in production.

  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, 2a ... Corner | angular part, 3, 23, 33 ... Sealing electrode, 4 ... Discharge auxiliary part, 5 ... Flange part, 6 ... Projection electrode part, 7, 27, 37 ... Positioning protrusion

Claims (4)

A rectangular tubular 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 discharge auxiliary portion formed of an ion source material other than the vicinity of a corner portion of the inner peripheral surface of the inner peripheral surface of the insulating tube;
A pair of sealing electrodes, a pair of flange portions fixed in close contact with both end openings of the insulating tube;
A pair of protruding electrode portions protruding inward from the pair of flange portions and facing each other;
A surge having a plurality of positioning protrusions projecting inwardly from the pair of flange portions and disposed in the vicinity of at least two opposing corners on the inner peripheral surface of the insulating tube Protective element. The surge protection element according to claim 1,
The surge protection element, wherein the positioning protrusions are provided in the vicinity of four corners on the inner peripheral surface of the insulating tube. The surge protection element according to claim 1 or 2,
The surge protection element according to claim 1, wherein the positioning protrusion has a smaller outer periphery toward the tip. In the surge protection element according to any one of claims 1 to 3,
The surge protection element, wherein the positioning protrusion extends from the protruding electrode portion to the vicinity of the corner portion.

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