JP7079975B2 - Manufacturing method of discharge type surge absorbing element - Google Patents

Description

In the present invention, a plurality of discharge electrodes are arranged in parallel across a discharge gap in an airtight container made of glass, a conductive film for generating a trigger discharge is arranged, and a discharge gas is further enclosed in the airtight container. The present invention relates to a method for manufacturing a discharge type surge absorbing element.

6 to 8 show an example of this kind of discharge type surge absorbing element. The discharge type surge absorbing element 001 is a pair of elongated round bar-shaped discharge electrodes 003 in an airtight container 002 made of glass. , 003 and a trigger discharge member 004 made of ceramics such as forsterite, alumina, and steatite, which are insulating materials, are enclosed.

The pair of discharge electrodes 003 and 003 are arranged in parallel at a predetermined distance, and a discharge gap 005 is formed between the pair of discharge electrodes 003 and 003.
Further, one end of the lead terminals 006 and 006 is connected to the lower ends of the discharge electrodes 003 and 003, and the other end of the lead terminals 006 and 006 penetrates the sealing portion 007 of the airtight container 002. Is derived to the outside.

The discharge electrode 003 is made of a metal such as nickel having excellent conductivity and a nickel alloy having excellent oxidation resistance such as a nickel-manganese (Ni-Mn) alloy.
Further, on the surface of the discharge electrode 003, a film 009 containing a substance having good electron emission characteristics is formed.

The trigger discharge member 004 is arranged on the sealing portion 007 of the airtight container 002, and as shown in an enlarged manner in FIGS. 7 and 8, the substantially elliptical main body portion 010 and the main body portion 010 are provided. It has a pair of holes 011 and 011 that penetrate vertically.
The holes 011 and 011 have substantially the same diameter as the external dimensions of the discharge electrode 003, and the discharge electrodes 003 and 003 and the lead terminals 006 and 006 are inserted into the holes 011 and 011.

Between the pair of holes 011 and 011 of the trigger discharge member 004, a conductive film 012 made of a carbon-based material or the like protrudes from the surface of the main body 010 at a predetermined height (for example, a height of about 1 mm). A convex portion 013 is formed, and a part of both end edges of the convex portion 013 is inserted into the holes 011 and 011 with a small discharge gap 015 as shown in FIG. The discharge electrodes 003 and 003 are arranged along approximately half the circumference of the outer surface on the inner side. Then, the conductive coating 012 on the surface of the convex portion 013 and the discharge electrodes 003 and 003 are arranged so as to face each other across the outer surface on the inner side of the discharge electrodes 003 and 003 with the minute discharge gap 015 in between. Has been done. The minute discharge gap 015 is set in the range of, for example, 10 to 50 μm.
The conductive film 012 is formed, for example, by rubbing a core material made of a carbon-based material.

The airtight container 002 is filled with a predetermined discharge gas, for example, a rare gas such as argon, neon, helium, or xenone, or an inert gas such as nitrogen gas, or a mixed gas.

When a surge is applied to the discharge type surge absorbing element 001 having the above configuration via the lead terminals 006 and 006, the electric field is concentrated in the minute discharge gap 015 between the conductive coating 012 and each of the discharge electrodes 003 and 003. As a result, electrons are emitted into the minute discharge gap 015 to generate a trigger discharge. This trigger discharge then shifts to glow discharge due to the electron priming effect. Then, this glow discharge is transferred to the discharge gap 005 due to the increase in the surge current, and further shifts to the arc discharge as the main discharge to absorb the surge.

Japanese Patent Application Laid-Open No. 2002-334765 Japanese Unexamined Patent Publication No. 2005-19803 Japanese Unexamined Patent Publication No. 2012-155882 (see FIGS. 1 to 3)

In the discharge type surge absorbing element 001, since the conductive coating 012 that generates a trigger discharge between the discharge electrodes 003 and 003 is arranged in the airtight container 002, the conductive coating 012 is adhered to the surface. A trigger discharge member 004 made of ceramic was required.
Therefore, it is necessary to manufacture and prepare the trigger discharge member 004 to which the conductive coating 012 is adhered, and to assemble the discharge electrodes 003 and 003 and the lead terminals 006 and 006 to the trigger discharge member 004. Due to the need for the discharge member 004, the manufacturing process is complicated and the cost is high.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is a discharge type surge absorbing element capable of arranging a conductive film for generating a trigger discharge in an airtight container by a simple method. It is to realize the manufacturing method.

In order to achieve the above object, the method for manufacturing a discharge type surge absorbing element according to claim 1 of the present invention is used.
A step of preparing a dispersion liquid obtained by mixing a powder of a conductive material in a solvent and a resin adhesive.
The process of rotating an elongated glass tube with both ends open,
With the glass tube rotated, droplets of the dispersion liquid are ejected from the tip of the nozzle of the inkjet device toward a predetermined position on the inner surface of the glass tube, whereby the dispersion liquid is formed into a band on the inner surface of the glass tube. The process of applying to form a conductive film,
A plurality of discharge electrodes to which one end of a lead terminal is connected are inserted into a glass tube through an opening at one end while holding a plurality of discharge electrodes connected in parallel with a predetermined gap, and the other end of the lead terminal protrudes from the glass tube to the outside. The process of storing as you like,
A process in which the vicinity of one end opening of a glass tube is heated and melted, the melted portion is crushed inward and sealed, and a sealing portion is formed.
A process of filling the glass tube with an electric discharge gas and then heating and melting the other end opening of the glass tube to seal it tightly.
It is characterized by having.

The method for manufacturing a discharge type surge absorbing element according to claim 2 of the present invention is the method for manufacturing a discharge type surge absorbing element according to claim 1.
The powder of the conductive material is characterized by being a carbon-based powder.

The method for manufacturing the discharge type surge absorbing element of the present invention includes a process of manufacturing and preparing a trigger discharge member 004 such as the conventional discharge type surge absorbing element 001, discharge electrodes 003 and 003 to the trigger discharge member 004, and lead terminals 006. The assembly process of 006 is unnecessary.
That is, in the method of manufacturing the discharge type surge absorbing element of the present invention, the powder of the conductive material is mixed in the solvent and the resin adhesive in a state where the glass tube which is the base of the airtight container is rotated. A conductive film to be arranged on the inner surface of the airtight container can be formed by a simple step of injecting droplets of the dispersion liquid toward a predetermined position on the inner surface of the glass tube.

The discharge type surge absorbing element 10 according to the present invention shown in FIGS. 1 and 2 is formed by enclosing a pair of elongated round bar-shaped discharge electrodes 14 and 14 in an airtight container 12 made of transparent glass.
The pair of discharge electrodes 14 and 14 are arranged in parallel at a predetermined distance, and a discharge gap 16 is formed between the pair of discharge electrodes 14 and 14.

Further, one end of a lead terminal 18 or 18 made of a Dumet wire (copper-coated iron-nickel alloy wire), a 42-6 alloy wire, or the like is connected to the lower ends of the discharge electrodes 14 and 14, and the lead terminal 18 is connected. The other end of, 18 is led out to the outside through the sealing portion 12a of the airtight container 12.

The discharge electrode 14 is made of a metal such as nickel having excellent conductivity or a nickel alloy having excellent oxidation resistance such as a nickel-manganese (Ni—Mn) alloy.
Further, on the surface of the discharge electrode 14, a film 20 containing a substance having good electron emission characteristics is formed.

The coating film 20 containing a substance having good electron emission characteristics can be formed, for example, by a coating film 20 containing a carbonate of an alkali metal and / or an alkaline earth metal and titanium carbide (TiC).

Cs ₂ CO ₃ (cesium carbonate) can be preferably used as the carbonate of the alkali metal, and BaCO ₃ (barium carbonate), (Ba, Sr,) can be preferably used as the carbonate of the alkaline earth metal. Ca) CO ₃ (ternary carbonate) can be preferably used.

The coating film 20 is a discharge electrode obtained by adding a carbonate powder of an alkali metal and / or a carbonate powder of an alkaline earth metal and a powder of titanium carbide to a binder composed of a sodium silicate solution and pure water. 14 Can be formed by applying to the surface.

A predetermined discharge gas is sealed in the airtight container 12. The discharge gas corresponds to, for example, a rare gas such as argon, neon, helium, or xenone, or a simple substance or a mixed gas of an inert gas such as nitrogen gas.

A conductive film 22 containing a conductive material having good electron emission characteristics is adhered to the inner surface of the airtight container 12 made of glass. In the case of this embodiment, a carbon-based material such as graphite, carbon black, or carbon nanotube is used as the conductive material.
As shown in FIGS. 1 and 2, the conductive coating 22 is adhered to the inner surface of the airtight container 12 in a band shape surrounding the pair of discharge electrodes 14 and 14 in a direction intersecting the pair of discharge electrodes 14 and 14. It is formed.
In the present embodiment, the band-shaped conductive coating 22 is seamlessly formed over the entire inner surface of the airtight container 12 to surround the entire pair of discharge electrodes 14 and 14 (see FIG. 2).
The band-shaped conductive coating 22 may be formed so that there is a notch on the inner surface of the airtight container 12 so as to partially surround the pair of discharge electrodes 14 and 14.

The discharge type surge absorbing element 10 is manufactured by the following process.
First, an elongated cylindrical transparent glass tube 24 having both ends opened, which is the base of the airtight container 12, is prepared (see FIG. 3).

Further, the powder of the conductive material constituting the conductive coating 22 is mixed in the solvent and the resin adhesive to prepare an ink-like dispersion liquid in which the powder of the conductive material is mixed. In this embodiment, carbon-based powders such as graphite, carbon black, and carbon nanotubes are used as the conductive material.
Examples of the solvent include alcohol-based solvents, methyl ethyl ketone-based solvents, acetone-based solvents, and water-based solvents.
Further, the resin adhesive corresponds to an adhesive of a cellulosic resin, an acrylic resin, an epoxy resin, or a urethane resin.
The produced ink-like dispersion liquid is supplied to the inkjet device.

Next, the glass tube 24 is rotated in the direction indicated by the rotation arrow in FIG. 3A (the direction in which the central axis in the longitudinal direction of the glass tube 24 is the rotation axis).
Then, with the glass tube 24 continuously rotated, the droplets of the dispersion liquid 30 are continuously ejected from the tip of the nozzle 26 of the inkjet device toward a predetermined position on the inner surface of the glass tube 24 from diagonally above. do.
As a result, as shown in FIG. 3B, the dispersion liquid 30 is applied in a band shape on the inner surface of the glass tube 24.
At this time, by continuously rotating the glass tube 24 many times, the dispersion liquid 30 can be applied in a band shape without a break over the entire circumference of the inner surface of the glass tube 24.
Further, by appropriately adjusting the rotation speed and rotation speed of the glass tube 24 and the injection amount and injection time of the droplets of the dispersion liquid 30 ejected from the tip of the nozzle 26 of the inkjet device, the dispersion liquid 30 can be applied to the inner surface of the glass tube 24. It can also be applied in a strip shape so that there is a cut on the non-total circumference.
After that, the dispersion liquid 30 dries to form the conductive film 22 of the discharge type surge absorbing element 10.

Next, the pair of discharge electrodes 14 and 14 to which one ends of the lead terminals 18 and 18 are connected are inserted into the glass tube 24 through the opening at one end while holding the pair of discharge electrodes 14 and 14 in parallel with a predetermined gap. Store the terminals 18 and 18 so that the other ends protrude from the glass tube to the outside.

Next, the vicinity of one end opening of the glass tube 24 is heated and melted, and the melted portion is crushed inward to seal the glass tube 24 to form the sealing portion 12a.

Next, an exhaust device (not shown) is connected to the other end opening of the glass tube 24, and the air inside is discharged to bring the inside of the glass tube into a high vacuum state, and then the discharge gas is filled.
Next, the discharge type surge absorbing element 10 is completed by airtightly sealing the opening at the other end of the glass tube 24 by heating and melting it to seal it.

The manufacturing method of the present invention is a step of manufacturing and preparing a trigger discharge member 004 such as a conventional discharge type surge absorbing element 001, and a step of assembling the discharge electrodes 003 and 003 and the lead terminals 006 and 006 to the trigger discharge member 004. Is unnecessary.
That is, in the production method of the present invention, in a state where the glass tube 24 which is the base of the airtight container 12 is rotated, the powder of the conductive material is mixed in the solvent and the resin adhesive to form the dispersion liquid 30. The conductive film 22 arranged on the inner surface of the airtight container 12 can be formed by a simple step of ejecting the droplets toward a predetermined position on the inner surface of the glass tube 24.

When a surge is applied to the discharge type surge absorbing element 10 having the above configuration via the lead terminals 18 and 18, electrons are generated between the conductive coating 22 formed on the inner surface of the airtight container 12 and the discharge electrodes 14 and 14. Is released and a trigger discharge occurs.
This trigger discharge then shifts to glow discharge due to the electron priming effect. Then, this glow discharge is transferred to the discharge gap 16 due to the increase in the surge current, and further shifts to the arc discharge as the main discharge to absorb the surge.

As described above, since the conductive coating 22 is formed in a band shape surrounding the pair of discharge electrodes 14, 14, trigger discharge is generated over a wide range between the conductive coating 22 and the respective discharge electrodes 14, 14. be able to.
In particular, as in the present embodiment, when a band-shaped conductive coating 22 is formed on the entire inner surface of the airtight container 12 and surrounds the entire pair of discharge electrodes 14 and 14, the trigger discharge can be generated in the widest range, which is optimal. Is.

Therefore, in the discharge type surge absorbing element 10 of the present invention, the conductive coating 22 that generates a trigger discharge between the discharge electrodes 14 and 14 is formed on the inner surface of the airtight container 12 made of glass. The trigger discharge member 004 in the conventional discharge type surge absorbing element 001 is unnecessary, and a low-cost discharge type surge absorbing element 10 with a small number of parts can be realized.

Further, since the conductive coating 22 is formed on the inner surface of the airtight container 12 made of glass, the discharge electrodes 14 and 14 are sputtered and scattered by the impact at the time of discharge, and the amount of the electrode material adhered to the conductive coating 22 is small. As a result, deterioration of insulation and destabilization of the discharge start voltage are suppressed, and a long-life discharge type surge absorbing element 10 can be realized.

FIG. 4 shows the relationship between the number of surge applications (5000 times) and the insulation resistance (MΩ) in the discharge type surge absorbing element 10 (3 pieces) according to the present invention and the conventional discharge type surge absorbing element 001 (3 pieces). It is a graph which shows. The applied impulse current waveform is 8/20 μs-100A.
As shown in the graph of FIG. 4, in the case of the conventional discharge type surge absorbing element 001 (graph B of FIG. 4), the insulation resistance sharply decreases from the time when the number of applications exceeds 2000 times, and the insulation deteriorates. On the other hand, in the case of the discharge type surge absorbing element 10 of the present invention (graph A in FIG. 4), no significant change is observed in the insulation resistance up to 3000 times of application, and the number of times of application exceeds 3000 times. However, since the decrease in insulation resistance is gradual, deterioration of insulation is suppressed as compared with the conventional discharge type surge absorbing element 001, and a longer life is realized.

FIG. 5 is a graph showing the relationship between the impulse discharge start voltage (kV) and the number of surge applications (300 times) in the discharge type surge absorbing element 10 according to the present invention and the conventional discharge type surge absorbing element 001. The applied voltage / current waveform is 1.2 / 50 μs (R = 12Ω) -15 kV / 1.25 kA.
The impulse discharge start voltage is a voltage value at which the discharge type surge absorbing element 10 starts discharging when a predetermined value of impulse (surge) voltage is applied.

As shown in the graph of FIG. 5, in the case of the conventional discharge type surge absorbing element 001 (graph Y of FIG. 5), the impulse discharge start voltage is unstable due to a large variation as the number of applications increases. On the other hand, in the case of the discharge type surge absorbing element 10 of the present invention (graph X in FIG. 5), the impulse discharge start voltage is stable even when applied 300 times, and the life is extended.

It is a schematic sectional drawing which shows the discharge type surge absorption element which concerns on this invention. FIG. 1 is an enlarged schematic cross-sectional view taken along the line AA of FIG. It is explanatory drawing which shows typically the manufacturing method of the discharge type surge absorption element which concerns on this invention. It is a graph which shows the relationship between the number of times of surge application and insulation resistance in the discharge type surge absorption element which concerns on this invention, and the conventional discharge type surge absorption element. It is a graph which shows the relationship between the impulse discharge start voltage and the number of times of surge application in the discharge type surge absorption element which concerns on this invention, and the conventional discharge type surge absorption element. It is a schematic sectional drawing which shows the conventional discharge type surge absorption element. It is a partially enlarged sectional view which shows the discharge electrode and the trigger discharge member of the conventional discharge type surge absorption element. FIG. 7 is a schematic cross-sectional view taken along the line XX of FIG.

10 Discharge type surge absorbing element
12 Airtight container
14 Discharge electrode
16 Discharge gap
18 Lead terminal
20 coating
22 Conductive coating
24 glass tube
26 Inkjet appliance nozzle
30 Dispersion

Claims (2)

A step of preparing a dispersion liquid obtained by mixing a powder of a conductive material in a solvent and a resin adhesive.
The process of rotating an elongated glass tube with both ends open,
With the glass tube rotated, droplets of the dispersion liquid are ejected from the tip of the nozzle of the inkjet device toward a predetermined position on the inner surface of the glass tube, whereby the dispersion liquid is formed into a band on the inner surface of the glass tube. The process of applying to form a conductive film,
A plurality of discharge electrodes to which one end of a lead terminal is connected are inserted into a glass tube through an opening at one end while holding a plurality of discharge electrodes connected in parallel with a predetermined gap, and the other end of the lead terminal protrudes from the glass tube to the outside. The process of storing as you like,
A process in which the vicinity of one end opening of a glass tube is heated and melted, the melted portion is crushed inward and sealed, and a sealing portion is formed.
A process of filling the glass tube with an electric discharge gas and then heating and melting the other end opening of the glass tube to seal it tightly.
A method for manufacturing a discharge type surge absorbing element. The method for manufacturing a discharge type surge absorbing element according to claim 1, wherein the powder of the conductive material is a carbon-based powder.

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