JP4910950B2 - surge absorber - Google Patents

Description

  The present invention relates to a surge absorber used for protecting various devices from a surge caused by a lightning strike or the like and preventing an accident in advance.

  Portions where electronic devices for communication devices such as telephones, facsimiles, modems, etc. are connected to communication lines, power lines, antennas, CRT drive circuits, etc., portions that are susceptible to electrical shock due to abnormal voltage (surge voltage) such as lightning surge or static electricity A surge absorber is connected to prevent damage due to thermal damage or ignition of an electronic device or a printed circuit board on which the device is mounted due to an abnormal voltage.

  Conventionally, a surge absorber using a surge absorbing element having a micro gap has been proposed as a surge absorber having a good response, as shown in Patent Document 1, for example. In this surge absorber, a so-called microgap is formed on the peripheral surface of a ceramic member, which is a cylindrical insulating member encapsulated with a conductive film, and a surge absorbing element having a pair of cap electrodes at both ends of the ceramic member is discharged. It is a discharge type surge absorber in which sealing electrodes that are housed in a glass tube together with a control gas and have lead wires on both ends of a cylindrical glass tube are sealed by high-temperature heating.

  On the other hand, as shown in Patent Document 2, for example, a plurality of discharge electrodes made of rod-shaped discharge bases are arranged opposite to each other with a discharge gap therebetween, and this is enclosed in an airtight container together with a discharge gas and connected to the lower end of the electrode base body. In the discharge type surge absorbing element in which the lead terminals are led out of the hermetic vessel, a carbon trigger wire type electrode in which a carbon wire trigger electrode is provided with a small gap from each discharge electrode on the surface of the dielectric base in the hermetic vessel. Discharge type surge absorbers have been proposed.

JP 2003-282216 A Japanese Patent No. 2745393

The following problems remain in the conventional technology.
In other words, the microgap type surge absorber as shown in Patent Document 1 has a disadvantage in that many steps such as film formation are required to manufacture the element, and the manufacturing cost is high. Moreover, in the carbon trigger wire type surge absorber as shown in Patent Document 2, the carbon wire must be drawn on the surface of the insulator (dielectric base) facing the discharge, which causes a cost increase at least during mass production. It was.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a surge absorber that can be manufactured at low cost and has high-speed response.

  The present invention employs the following configuration in order to solve the above problems. That is, a surge absorber according to the present invention includes a columnar or cylindrical insulating member, a pair of terminal electrode members that are opposed to both ends of the insulating member and in contact with the both ends, and the pair of terminal electrode members An insulating tube that seals the insulating member together with a discharge control gas inside at both ends, the terminal electrode from the contact portion that contacts the terminal electrode member at both ends of the insulating member A tapered surface that is inclined so as to be gradually separated from the member and extends in the radial direction is formed, and a discharge space groove extending along an axis and connecting the both end portions is formed on the outer peripheral portion of the insulating member. It is formed.

In this surge absorber, tapered surfaces extending in the radial direction are formed at both ends of the insulating member so as to be gradually separated from the terminal electrode member from the contact portion that contacts the terminal electrode member. A groove having a V-shaped cross section is formed between the tapered surface and the terminal electrode member, and trigger discharge is performed in this groove when a surge occurs. Therefore, since the insulating member with the tapered surface is sealed in the insulating tube, it can be manufactured easily and at a low cost, and high-speed response can be obtained by trigger discharge by the groove. Can do. Furthermore, the responsiveness can be improved by appropriately setting the angle between the tapered surface and the terminal electrode member (the groove angle) to an angle corresponding to the surge.
Furthermore, since a discharge space groove extending along the axis and connecting both ends is formed on the outer peripheral portion of the insulating member, it is triggered by a minute space (groove) between the tapered portion and the terminal electrode member. Since the minute discharge is developed at a short distance through the discharge space groove, higher response to the impulse can be obtained.
If the outer peripheral portion of the insulating member is not formed with a discharge space groove, the triggered surface must once creep along the outer peripheral surface after progressing radially outwardly different from the electric field direction. However, it is difficult to sufficiently improve the responsiveness because the discharge distance is extended and the progress is easily hindered. However, in the present invention, there is almost no distance at which the discharge progresses radially outward by creeping discharge in the discharge space groove, and high responsiveness is obtained by developing at the shortest distance.
In addition, since the discharge space groove is formed, the cross-sectional area becomes smaller than the apparent outer shape, a wide discharge space is secured on the outer peripheral surface, the amount of discharge control gas filled can be increased, and a large current Can be discharged.

  The surge absorber of the present invention is characterized in that a plurality of the discharge space grooves are formed. That is, in this surge absorber, since a plurality of grooves for the discharge space are formed, more discharge spaces are secured, the amount of discharge control gas enclosed can be increased, and a larger current is discharged. be able to.

  Furthermore, the surge absorber of the present invention projects radially from the axial portion to the inner surface of the insulating tube radially outward from the axial portion and extends along the axial line to connect the both end portions to the outer peripheral portion of the insulating member. A plurality of protrusions are formed, and the discharge space groove is formed between the adjacent protrusions. That is, in this surge absorber, since the protrusion is formed to protrude radially to the inner surface of the insulating tube, the tip of the protrusion is in contact with the insulating tube and the insulating member is supported in the insulating tube. Positioned. Thereby, when an insulating member is thrown in in an insulating pipe | tube, it can prevent falling down.

The present invention has the following effects.
That is, according to the surge absorber according to the present invention, the taper that extends in the radial direction is inclined at both ends of the insulating member so as to be gradually separated from the terminal electrode member from the contact portion that contacts the terminal electrode member. Since the surface is formed, it can be easily manufactured at a low cost with a simple configuration, and high-speed response can be obtained by trigger discharge by a groove between the tapered surface and the terminal electrode member. Furthermore, since the discharge space groove extending along the axis and connecting the both ends is formed on the outer peripheral portion of the insulating member, the discharge progresses in a short distance and high responsiveness can be obtained. A large discharge space is secured, and a large current can be discharged by increasing the amount of discharge control gas enclosed.

  Hereinafter, a first embodiment of a surge absorber 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 FIG. 1, the surge absorber 1 of the present embodiment includes a columnar insulating member 2, a pair of terminal electrode members 3 that are disposed opposite to both ends of the insulating member 2 and are in contact with the both ends. A pair of terminal electrode members 3 at both ends and an insulating tube 4 that seals the insulating member 2 with a discharge control gas (not shown) inside, and a base end on the outer end surface of the pair of terminal electrode members 3 And a pair of fixed lead wires 5.

The insulating member 2 is an insulator having a relative dielectric constant of 5 to 100, preferably 8.5 to 40, having a relative dielectric constant larger than that of the insulating tube 4 and having a relative dielectric constant of about zirconia. is there.
At both ends of the insulating member 2, tapered surfaces 2 a that are inclined so as to be gradually separated from the terminal electrode member 3 from the central contact portion that contacts the terminal electrode member 3 to the outer peripheral surface and extend in the radial direction. Is formed. That is, a groove is formed between the tapered surface 2 a and the terminal electrode member 3. The tapered surface 2a is in contact with the terminal electrode member 3 at a certain angle. The angle between the tapered surface 2a and the terminal electrode member 3 is set in the range of 1 to 60 °.

In addition, a plurality of protrusions 2b are formed on the outer peripheral portion of the insulating member 2 so as to project radially from the axial portion to the inner surface of the insulating tube 4 radially outward and extend along the axial line to connect both ends. Has been. A plurality of discharge space grooves 2c extending along the axis and connecting both ends are formed between the adjacent protrusions 2b on the outer peripheral portion of the insulating member 2.
In the insulating member 2 of the first embodiment, the four ridges 2b protrude radially from the axis, and the cross-sectional shape orthogonal to the axis is a cross shape.

The terminal electrode member 3 is a discharge electrode and is sealed at both ends of the insulating tube 4 by high-temperature heating, and sealed so that the central axis of the insulating member 2 coincides with the central axis of the insulating tube 4. Stopped.
The insulating tube 4 is formed of a glass tube such as lead glass or a ceramic tube.
The discharge control gas is an inert gas such as He, Ar, Ne, Xe, SF ₆ , CO ₂ , C ₃ F ₈ , C ₂ F ₆ , CF ₄ , H _2, or a mixed gas thereof.

  In order to produce this surge absorber 1, first, the insulating member 2 is held between the pair of terminal electrode members 3, and inserted into the insulating tube 4 in this state. Then, after the air in the insulating tube 4 is replaced with a predetermined discharge control gas (for example, Ar), both ends of the insulating tube 4 are heated and melted to be brought into close contact with the terminal electrode member 3 and sealed. . Thereby, the surge absorber 1 in which the insulating member 2 is sealed in the insulating tube 4 is obtained.

  In this surge absorber 1, when overvoltage or overcurrent enters, trigger discharge is first performed in the groove between the taper surface 2 a and the terminal electrode member 3, and further discharge progresses to form a discharge space groove in the insulating member 2. Surge is absorbed by creeping discharge in 2c.

  As described above, in the surge absorber 1 according to the present embodiment, the both ends of the insulating member 2 are inclined so as to be gradually separated from the terminal electrode member 3 from the contact portion that contacts the terminal electrode member 3 and extend in the radial direction. Since the existing tapered surface 2a is formed, a groove having a V-shaped cross section is formed between the tapered surface 2a and the terminal electrode member 3, and trigger discharge is performed in this groove when a surge occurs.

  Accordingly, since the insulating member 2 with the tapered surface 2a is sealed in the insulating tube 4, it can be manufactured easily and at low cost, and at the same time a high-speed response is achieved by the trigger discharge by the groove. Sex can be obtained. Furthermore, it is also possible to improve the responsiveness by appropriately setting the angle (groove angle) between the tapered surface 2a and the terminal electrode member 3 to an angle corresponding to the surge.

Further, since a discharge space groove 2c extending along the axis and connecting both ends is formed on the outer peripheral portion of the insulating member 2, as shown in FIG. 2A, the tapered surface 2a and the terminal Since the micro discharge triggered in the micro space (groove) between the electrode members 3 develops in a short distance via the discharge space groove 2c, higher response to the impulse can be obtained.
As shown in FIG. 2B, if the discharge space groove 2c is not formed on the outer peripheral portion of the insulating member 12, the microdischarge triggered by the tapered portion 12a once has a radius different from the electric field direction. After progressing outward in the direction, the surface of the outer peripheral portion must be subjected to creeping discharge, the discharge distance is extended, and the progress is easily hindered, making it difficult to sufficiently improve the responsiveness. However, in the present embodiment, there is almost no distance at which the discharge progresses radially outward by creeping discharge in the discharge space groove 2c, and high responsiveness is obtained by developing at the shortest distance.

In addition, the cross-sectional shape is a polygonal cross shape, and a plurality of discharge space grooves 2c are formed, so that the cross-sectional area is smaller than the apparent outer shape, a wide discharge space is secured on the outer peripheral surface, and discharge control is performed. The amount of gas enclosed can be increased, and a large current can be discharged.
Further, since the protrusion 2b is formed to protrude radially to the inner surface of the insulating tube 4, the tip of the protrusion 2b contacts the insulating tube 4, and the insulating member 2 is supported in the insulating tube 4. To be positioned. Thereby, when the insulating member 2 is put into the insulating tube 4, it can be prevented from falling down.

  Next, the second to sixth embodiments of the surge absorber 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 tapered surface 2a of the insulating member 2 is formed from the contact portion at the center of both ends to the outer peripheral surface. In the surge absorber 21 of the second embodiment, as shown in FIG. 3, the center is a recess 22 d at both ends of the insulating member 22, and the periphery is a contact portion. That is, in the surge absorber 21 of the second embodiment, the tapered surface 22a is also formed on the inner surface of the recess 21d. Therefore, trigger discharge occurs on either the tapered surface 22a on the inner surface of the recess 22d or the outer tapered surface 22a, and the surge is absorbed by creeping discharge in the discharge space groove 22c. In the second embodiment, the discharge space can be increased by the amount of the recess 22d.

  The difference between the third embodiment and the first embodiment is that, in the first embodiment, the ridge portion 2b employs a cross-shaped insulating member 2 having a cross-sectional shape projecting in four directions around the axis. On the other hand, in the surge absorber 31 of the third embodiment, as shown in FIG. 4, the protrusion 32b employs an insulating member 32 that protrudes radially in three directions around the axis. That is, in the surge absorber 31 of the third embodiment, the trigger discharge generated in any one of the three tapered surfaces 32a is creepingly discharged in the three discharge space grooves 32c to absorb the surge. In the third embodiment, the discharge space can be further increased by the amount of the protrusions 32b being reduced from four to three.

  The difference between the fourth embodiment and the second embodiment is that, in the second embodiment, the ridge 22b employs a cross-shaped insulating member 22 having a cross-sectional shape that protrudes in four directions around the axis. On the other hand, in the surge absorber 41 of the fourth embodiment, as shown in FIG. 5, as in the third embodiment, the protruding portion 42b employs an insulating member 42 that protrudes radially in three directions around the axis. Is a point. That is, in the surge absorber 41 of the fourth embodiment, the trigger discharge generated on any of the three tapered surfaces 42a in the recess 42d and the outer three tapered surfaces 42a is caused by any of the three discharge space grooves 42c. The surge is absorbed by creeping discharge.

  The difference between the fifth embodiment and the first embodiment is that in the first embodiment, the four tapered surfaces 2a are all at the same inclination angle with respect to the terminal electrode member 3, whereas the surge of the fifth embodiment is different. In the absorber 51, as shown in FIG. 6, the two tapered surfaces 52a out of the four tapered surfaces 52a are set to have a larger inclination angle than the other two tapered surfaces 52a. In other words, the surge absorber 51 of the fifth embodiment has two pairs of protrusions 52b having different shapes and having two pairs of tapered surfaces 52a having different inclination angles. Therefore, since the surge absorber 51 of the fifth embodiment has the tapered surface 52a having different inclination angles, the trigger discharge is performed on the tapered surface 52a having the angle suitable for the surge level, and the responsiveness is further improved. Can be made.

  The difference between the sixth embodiment and the first embodiment is that, in the first embodiment, four protrusions 2b are formed on both end faces of the insulating member 2, respectively. In the surge absorber 61, as shown in FIG. 7, two pairs of protrusions 62 b whose projecting amount gradually decreases in the axial direction are alternately formed on the outer peripheral surface of the insulating member 62. The two taper surfaces 61a are formed on the both end surfaces of each. That is, in the surge absorber 61 of the sixth embodiment, the trigger discharge generated on the two tapered surfaces 62a on one side is creepingly discharged in the discharge space groove 62c and the surge is absorbed. In the sixth embodiment, the discharge space can be further increased by the amount by which the protruding amount of the protrusion 61b is gradually reduced.

  Next, the results of evaluating the surge absorber according to the present invention by the actually produced examples will be specifically described.

  As an example of the surge absorber according to the present invention, a surge absorber having the same form (cross-sectional shape) as the surge absorber 1 of the first embodiment was produced. Further, a glass tube was used as the insulating tube 4, and an insulator having a relative dielectric constant of 8.5 (Example) was used as the insulating member 2. The angle between the tapered surface 2a and the terminal electrode member 3 (groove angle) was set to 45 °. In addition, Ar was used as a gas sealed in the insulating tube 4.

Further, as Comparative Example 1, as shown in FIG. 2B, the discharge space groove 2c is not formed, but a cylindrical shape in which tapered surfaces 2a of 45 ° are formed on both end faces, and the relative permittivity is 8 A member using the insulating member 12 of .5 was produced in the same manner.
Furthermore, as Comparative Example 2, a cylindrical insulating member having a diameter smaller than that of Comparative Example 1 and the other conditions were the same.

For these Examples and Comparative Examples 1 and 2, the impact ratio (“impulse discharge start voltage” / “DC discharge start voltage”) was measured. The closer the impact ratio is to 1, the better the response. In addition, a voltage waveform of 1.2 / 50, 5 kV was applied as the impulse.
As a result of the evaluation, the impact ratio of the example was 2.2, the impact ratio of Comparative Example 1 was 2.6, and the impact ratio of Comparative Example 2 was 2.6. Thus, in the Example of this invention, it can be seen that the impact ratio is smaller than that of the comparative example, which is a value close to 1, and has high-speed response.

  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.

In 1st Embodiment of the surge absorber which concerns on this invention, it is the exploded perspective view of a surge absorber, and the side view which fractured | ruptured the insulating tube and the terminal electrode member, and exposed the insulating member. In 1st Embodiment of the surge absorber which concerns on this invention, it is a perspective view which shows this embodiment for demonstrating a discharge path, and a perspective view which shows a comparative example. In 2nd Embodiment of the surge absorber which concerns on this invention, it is the disassembled perspective view of a surge absorber, and the side view which fractured | ruptured the insulating pipe | tube and the terminal electrode member and exposed the insulating member. In 3rd Embodiment of the surge absorber which concerns on this invention, it is the exploded perspective view of a surge absorber, and the side view which fractured | ruptured the insulating tube and the terminal electrode member, and exposed the insulating member. In 4th Embodiment of the surge absorber which concerns on this invention, it is the exploded perspective view of a surge absorber, and the side view which fractured | ruptured the insulating tube and the terminal electrode member, and exposed the insulating member. In 5th Embodiment of the surge absorber which concerns on this invention, it is the exploded perspective view of a surge absorber, and the side view which fractured | ruptured the insulating tube and the terminal electrode member, and exposed the insulating member. In 6th Embodiment of the surge absorber which concerns on this invention, it is the exploded perspective view of a surge absorber, and the side view which fractured | ruptured the insulating tube and the terminal electrode member, and exposed the insulating member.

Explanation of symbols

  1, 21, 31, 41, 51, 61 ... surge absorber, 2, 12, 22, 32, 42, 52, 62 ... insulating member, 2a, 12a, 22a, 32a, 42a, 52a, 62a ... tapered surface, 2b, 22b, 32b, 42b, 52b, 62b ... ridges, 2c, 22c, 32c, 42c, 52c, 62c ... discharge space groove, 3 ... terminal electrode member, 4 ... insulating tube, 5 ... lead wire

Claims (3)

A columnar or tubular insulating member;
A pair of terminal electrode members disposed opposite to both ends of the insulating member and in contact with the both ends;
An insulating tube that arranges the pair of terminal electrode members at both ends and seals the insulating member together with a discharge control gas inside,
At both end portions of the insulating member, tapered surfaces extending in a radial direction are formed so as to be gradually separated from the terminal electrode member from a contact portion that contacts the terminal electrode member,
A surge absorber, wherein a discharge space groove extending along an axis and connecting the both end portions is formed on an outer peripheral portion of the insulating member. The surge absorber according to claim 1,
A surge absorber comprising a plurality of the discharge space grooves. The surge absorber according to claim 2,
A plurality of ridges are formed on the outer peripheral portion of the insulating member, radially projecting radially outward from the axial portion to the inner surface of the insulating tube and extending along the axial line and connecting the both ends.
The surge absorber, wherein the discharge space groove is formed between the adjacent protrusions.

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