JP2018156800A - Surge protective element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surge protective element capable of suppressing fluctuations in a discharge start voltage Vs more than in the conventional way even if the size of a protrusion electrode part is fluctuated.SOLUTION: A surge protective element includes: an insulation tube; a pair of sealing electrodes which block both-end openings of the insulation tube to seal the inside with discharge control gas; a columnar or cylindrical insulation member 4 which is arranged in the insulation tube; a pair of cap electrodes 5 which are provided at both ends of an insulation member and in contact with the inner surfaces of sealing electrodes opposite to each other; and a discharge auxiliary part 6 formed of an ion source material in an intermediate part in the axial line C direction of the insulation member. A cap electrode has a cap outer peripheral part 5a covering the outer peripheral surface of the end side of the insulation member. The outer peripheral edge 5b on the end surface of the cap outer peripheral part protrudes in the axial line C direction more than the inner peripheral edge 5c.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 Document 1, for example, an arrester type surge protection provided with 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 An element is described.
Further, as shown in Patent Document 2, a glass tube, a pair of sealing electrodes for closing the opening at both ends of the glass tube and sealing the discharge gas inside, and a pair of sealing electrodes at both ends are arranged. A surge absorber including an insulator housed in a glass tube and a metal flat plate interposed between at least one of the pair of sealing electrodes and the insulator is described. In this surge absorber, a trigger portion made of a conductive material such as carbon is provided at an intermediate portion between the front and back surfaces of the insulator.

JP 11-354244 A JP 2014-154528 A

The following problems remain in the conventional technology.
In the prior art, there is a problem that the discharge auxiliary voltage such as the carbon trigger is easily damaged by repeated discharge, and the discharge start voltage and the response voltage are increased.
Further, in the conventional technique, discharge auxiliary parts such as carbon triggers are sparsely present at a plurality of locations on the inner peripheral surface of the insulating tube, or partially present in the middle part of the insulator, so that the discharge path There is a place where the discharge auxiliary portion does not exist above, and there is a disadvantage that the stability of the discharge start voltage and surge response is lacking.

  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 is excellent in durability and can obtain high stability of surge characteristics such as a discharge start voltage.

  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 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 therein, and the inside of the insulating tube. A columnar or cylindrical insulating member disposed on the insulating member, a pair of cap electrodes provided at both ends of the insulating member and in contact with the opposing inner surfaces of the sealing electrode, and an axially intermediate portion of the insulating member An auxiliary discharge portion formed of an ion source material on the surface of the cap member, and the cap electrode has a cap outer peripheral portion covering an outer peripheral surface on the end portion side of the insulating member, and an end surface of the cap outer peripheral portion The outer peripheral edge of is protruded in the axial direction from the inner peripheral edge.

  In this surge protection element, the cap electrode has a cap outer peripheral portion covering the outer peripheral surface on the end portion side of the insulating member, and the outer peripheral edge of the end surface of the cap outer peripheral portion protrudes in the axial direction from the inner peripheral edge. Therefore, it becomes easy to discharge from the outer peripheral edge at the end face of the protruding outer peripheral portion of the cap, and the main discharge is separated from the discharge auxiliary portion, so that the discharge auxiliary portion can be prevented from being damaged, and durability against repeated discharge is improved. Moreover, it can suppress that the metal scattered by discharge adheres to the outer peripheral surface of an insulating member because the main discharge generate | occur | produces in the outer periphery in the end surface of the cap outer peripheral part spaced apart from the outer peripheral surface of the insulating member. Furthermore, compared with the case where the discharge auxiliary portion is provided on the inner peripheral surface of the insulating tube, arc discharge occurs on the inner side away from the inner peripheral surface of the insulating tube, and the distance between the cap electrode and the discharge auxiliary portion is increased. The initial discharge is more likely to occur. Moreover, since arc discharge is generated in the vicinity of the outer peripheral surface of the insulating member, the discharge is easy to progress and the responsiveness is improved.

The surge protection element according to a second aspect of the present invention is characterized in that, in the first aspect, the end surface of the outer periphery of the cap is inclined with respect to the axis and directed toward the axis.
That is, in this surge protection element, the end surface of the cap outer periphery of the cap electrode is inclined with respect to the axis and is directed toward the axis, so that the outer periphery of the end surface of the cap outer periphery is an acute cross section. It becomes a shape and it becomes easier to discharge at the tip.

A surge protection element according to a third invention is characterized in that, in the first or second invention, the discharge assisting portion is formed in an annular shape extending in a circumferential direction.
That is, in this surge protection element, since the discharge auxiliary portion is formed in an annular shape extending in the circumferential direction, the discharge auxiliary portion always exists in the discharge path along the axial direction, so that the discharge start voltage and surge Responsive stability is improved.

The present invention has the following effects.
That is, according to the surge protection element according to the present invention, the cap electrode has a cap outer peripheral portion covering the outer peripheral surface on the end portion side of the insulating member, and the outer peripheral edge on the end surface of the cap outer peripheral portion is the inner peripheral edge. Further, since it protrudes more in the axial direction, damage to the auxiliary discharge portion can be suppressed, durability against repeated discharge is improved, and discharge start voltage and the like are stabilized.
Therefore, the surge protection element according to the present invention is excellent in durability, can obtain high stability of surge characteristics such as a discharge start voltage, and can obtain discharge characteristics having high reliability and high accuracy.

In 1st Embodiment of the surge protection element which concerns on this invention, it is sectional drawing which shows the insulating member which attached the cap electrode. In 1st Embodiment, it is the front view which fractured | ruptured only the insulating tube and the sealing electrode in the axial direction. In 2nd Embodiment of the surge protection element which concerns on this invention, it is the front view which fractured | ruptured only the insulating tube and the sealing electrode in the axial direction.

  Hereinafter, a first embodiment of a surge protection element according to the present invention will be described with reference to FIGS. 1 and 2. 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. Stop electrode 3, columnar or cylindrical insulating member 4 disposed in insulating tube 2, and a pair of cap electrodes in contact with the inner surfaces of sealing electrodes 3 provided at both ends of insulating member 4 and opposed to each other 5 and a discharge assisting portion 6 formed of an ion source material at an intermediate portion in the axis C direction of the insulating member 4.

The cap electrode 5 has a cap outer peripheral portion 5a covering the outer peripheral surface on the end portion side of the insulating member 4, and the outer peripheral edge 5b on the end surface of the cap outer peripheral portion 5a is more in the axis C direction than the inner peripheral edge 5c. It protrudes.
The end surface of the cap outer peripheral part 5a is inclined with respect to the axis C and is inclined toward the axis C. That is, the end surfaces of the pair of cap outer peripheral portions 5a facing each other are not parallel to each other but are inclined inward in the radial direction.
Moreover, the said discharge auxiliary | assistant part 6 is formed in the cyclic | annular form extended in the circumferential direction.

The insulating tube 2 is formed in a cylindrical shape with a crystalline ceramic material such as alumina.
The insulating member 4 is formed in a cylindrical shape with a crystalline ceramic material such as alumina.
The insulating member 4 is arranged with its axis aligned with the axis C of the insulating tube 2, and the cap electrode 5 and the inner surface of the insulating tube 2 are in a separated state.
The discharge auxiliary portion 6 is a conductive material, and is formed of, for example, a carbon material. The auxiliary discharge portion 6 is formed in an annular shape on the peripheral surface of the cylindrical insulating member 4.

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 is fixed in close contact with the opening at both ends of the insulating tube 2 by a heat treatment using a conductive fusing material (not shown).
The cap electrode 5 is formed of a metal such as stainless steel in a cap type in which the end of the insulating member 4 can be fitted and press-fitted.

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 , the atmosphere, etc. and a mixed gas thereof are employed.

  In this surge protection element 1, when overvoltage or overcurrent enters, first, initial discharge is preferentially performed between the discharge auxiliary portion 6 and the outer peripheral edge 5 b of the cap outer peripheral portion 5 a of the cap electrode 5. As a result, the discharge further progresses, and the discharge is mainly performed between the cap outer peripheral portions 5a of the pair of cap electrodes 5 facing each other.

  As described above, in the surge protection device 1 of the present embodiment, the cap electrode 5 has the cap outer peripheral portion 5a covering the outer peripheral surface on the end portion side of the insulating member 4, and the outer peripheral edge on the end surface of the cap outer peripheral portion 5a. Since 5b protrudes in the direction of the axis C from the inner peripheral edge 5c, it becomes easier to discharge from the outer peripheral edge 5b at the end face of the protruded cap outer peripheral part 5a, and the main discharge is separated from the discharge auxiliary part 6, whereby the discharge auxiliary part 6 can be suppressed, and durability against repeated discharge is improved.

  Further, the main discharge is generated at the outer peripheral edge 5b at the end face of the cap outer peripheral portion 5a that is separated from the outer peripheral face of the insulating member 4, thereby suppressing the metal scattered by the discharge from adhering to the outer peripheral face of the insulating member 4. it can. Further, compared to the case where the discharge auxiliary portion 6 is provided on the inner peripheral surface of the insulating tube 2, arc discharge occurs on the inner side away from the inner peripheral surface of the insulating tube 2, and the cap electrode 5 and the discharge auxiliary portion are provided. 6 and the initial discharge is more likely to occur. Moreover, since arc discharge occurs in the vicinity of the outer peripheral surface of the insulating member 4, the discharge is easy to progress and the responsiveness is also improved.

Further, since the end surface of the cap outer peripheral portion of the cap electrode 5 is inclined with respect to the axis C and is directed toward the axis C, the outer peripheral edge 5b on the end surface of the cap outer peripheral portion 5a has an acute cross-sectional shape. It becomes easier to discharge at the tip.
Further, since the discharge auxiliary portion 6 is formed in an annular shape extending in the circumferential direction, the discharge auxiliary portion 6 is always present in the discharge path along the axis C direction, so that the discharge start voltage and surge responsiveness can be improved. Stability is improved.

  Next, a second embodiment of the surge protection element according to the present invention will be described below with reference to FIG. Note that, in the following description of the embodiment, the same components 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 insulating tube 2 is a hollow ceramic type surge protection element formed of ceramics, whereas the surge of the second embodiment. As shown in FIG. 3, the protective element 21 is a glass tube type that employs an insulating tube 22 of a glass tube.

That is, in the second embodiment, the insulating tube 22 employs an amorphous tube such as lead glass, and the pair of sealing electrodes 23 have jumet wires 23a projecting outward on the axis. Embedded in the state.
Also in this 2nd Embodiment, the outer periphery 5b in the end surface of the cap outer peripheral part 5a protrudes in the axis C direction rather than the inner periphery 5c.

Thus, also in the surge protection element 21 of the second embodiment, the outer peripheral edge 5b on the end surface of the cap outer peripheral part 5a protrudes in the direction of the axis C from the inner peripheral edge, as in the first embodiment. 6 can be suppressed, and durability against repeated discharge is improved.
Further, since the discharge auxiliary portion 6 is formed in an annular shape extending in the circumferential direction, the discharge auxiliary portion 6 always exists in the discharge path along the axis C direction, so that the discharge start voltage and the surge responsiveness can be improved. Stability is improved.

  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 1,21 ... Surge protective element, 2,22 ... Insulating tube, 3,23 ... Sealing electrode, 4 ... Insulating member, 5a ... Cap outer peripheral part, 5b ... Outer peripheral edge in end surface of cap outer peripheral part, 5c ... Cap Inner peripheral edge at end face of outer peripheral part, 6 ... discharge auxiliary part, C ... axis of insulating tube and insulating member

Claims (3)

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 columnar or cylindrical insulating member disposed in the insulating tube;
A pair of cap electrodes in contact with the inner surfaces of the sealing electrodes provided at both ends of the insulating member and facing each other;
A discharge auxiliary portion formed of an ion source material on the surface of the intermediate portion in the axial direction of the insulating member;
The cap electrode has a cap outer peripheral portion covering an outer peripheral surface on the end portion side of the insulating member,
A surge protection element, wherein an outer peripheral edge of the end face of the outer peripheral portion of the cap protrudes in an axial direction from an inner peripheral edge. The surge protection element according to claim 1,
A surge protection element, wherein an end surface of the outer peripheral portion of the cap is inclined with respect to the axis and is directed toward the axis. The surge protection element according to claim 1 or 2,
The surge protection element, wherein the discharge auxiliary part is formed in an annular shape extending in the circumferential direction.

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