JP2019197615A - Manufacturing method of discharge type surge absorbing element - Google Patents

Abstract

To provide a manufacturing method of a discharge type surge absorbing element that can place a conductive coating that generates a trigger discharge in an airtight container in a simple manner.SOLUTION: A droplet of a dispersion liquid 30 obtained by mixing a conductive material powder in a solvent and a resin adhesive is attached to the tip of a needle 28 of a dispenser 26, and then the tip of the needle 28 is inserted into an elongated glass tube 24 having both ends serving as the base of a hermetic container 12 opened by a predetermined distance, and the glass tube 24 is rotated in a case in which the droplet of the dispersion liquid 30 is in contact with the inner surface of the glass tube 24, and therefore, a conductive film 22 is formed by applying the dispersion liquid 30 to the inner surface of the glass tube 24 in a strip shape.SELECTED DRAWING: Figure 3

Description

  According to the present invention, a plurality of discharge electrodes are arranged in parallel in a hermetic container made of glass with a discharge gap therebetween, a conductive film for generating a trigger discharge is disposed, and a discharge gas is sealed in the hermetic container. The present invention relates to a method for manufacturing a discharge type surge absorbing element.

  6 to 8 show an example of this type of discharge type surge absorbing element. The discharge type surge absorbing element 001 is disposed in a pair of elongated round bar-like discharge electrodes 003 in an airtight container 002 made of glass. , 003 and a trigger discharge member 004 made of an insulating material such as forsterite, alumina, steatite or the like.

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 discharge electrodes 003 and 003.
In addition, one end of lead terminals 006, 006 is connected to the lower ends of the discharge electrodes 003, 003, and the other end of the lead terminals 006, 006 penetrates the sealing part 007 of the airtight container 002. Are derived outside.

The discharge electrode 003 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, a coating film 009 containing a substance having good electron emission characteristics is formed on the surface of the discharge electrode 003.

The trigger discharge member 004 is disposed on the sealing portion 007 of the hermetic container 002, and as shown in an enlarged view in FIGS. It has a pair of holes 011 and 011 penetrating vertically.
The holes 011 and 011 have substantially the same diameter as the outer 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.

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

  A predetermined discharge gas, for example, a rare gas such as argon, neon, helium, xenon, or an inert gas such as nitrogen gas or a mixed gas is sealed in the airtight container 002.

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

JP 2002-334765 A JP 2005-190803 A JP 2012-155882 A (see FIGS. 1 to 3)

In the above-described discharge type surge absorbing element 001, the conductive film 012 that generates a trigger discharge between the discharge electrodes 003 and 003 is disposed in the hermetic container 002. A trigger discharge member 004 made of ceramic was required.
Therefore, the trigger discharge member 004 coated with the conductive coating 012 needs to be manufactured and prepared, the discharge electrodes 003 and 003 and the lead terminals 006 and 006 are assembled to the trigger discharge member 004, and the like. The manufacturing process is complicated due to the necessity of the discharge member 004, resulting in high costs.

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

In order to achieve the above object, a method for manufacturing a discharge type surge absorbing element according to claim 1 of the present invention provides:
A step of preparing a dispersion liquid obtained by mixing a powder of a conductive material in a solvent and a resin adhesive;
Attaching the droplet of the dispersion to the tip of the dispenser;
A step of inserting the tip of the dispenser into a long and narrow glass tube having both ends opened at a predetermined distance, and bringing a droplet of the dispersion into contact with the inner surface of the glass tube;
A process of forming a conductive film by applying the dispersion liquid to the inner surface of the glass tube by rotating the glass tube in a state where the droplets of the dispersion liquid are in contact with the inner surface of the glass tube;
A plurality of discharge electrodes connected to one end of the lead terminal are inserted into the glass tube through one end opening while being held 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
A step of heating and melting the vicinity of one end opening of the glass tube, crushing and sealing the melted portion inward, and forming a sealing portion;
A step of sealing hermetically by filling the glass tube with a discharge gas and then heating and melting and sealing the other end opening of the glass tube;
It is characterized by providing.

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

The manufacturing method of the trigger discharge member 004 like the conventional discharge type surge absorption element 001, the discharge electrodes 003 and 003 to the trigger discharge member 004 and the lead terminals 006, The assembly process of 006 is unnecessary.
That is, in the method for manufacturing a discharge type surge absorbing element according to the present invention, a droplet of a dispersion obtained by mixing a conductive material powder in a solvent and a resin adhesive is used as a glass tube as a base of an airtight container. After the contact with the inner surface, the conductive film disposed on the inner surface of the hermetic container can be formed by a simple method of rotating the glass tube and applying the dispersion liquid to the inner surface of the glass tube.

A 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-like 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 discharge electrodes 14 and 14.

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

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, a coating film 20 containing a substance having good electron emission characteristics is formed on the surface of the discharge electrode.

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

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

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

  A predetermined discharge gas is sealed in the airtight container 12. As this discharge gas, for example, a rare gas such as argon, neon, helium, xenon, or an inert gas such as nitrogen gas or a mixed gas is applicable.

On the inner surface of the hermetic container 12 made of glass, a conductive coating 22 containing a conductive material having good electron emission characteristics is deposited. In the present 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 deposited on the inner surface of the hermetic vessel 12 in a band shape surrounding the pair of discharge electrodes 14, 14 in a direction intersecting with the pair of discharge electrodes 14, 14. Is formed.
In the present embodiment, the whole of the pair of discharge electrodes 14 and 14 is surrounded by forming the strip-shaped conductive coating 22 seamlessly over the entire inner surface of the hermetic container 12 (see FIG. 2).
It should be noted that the strip-shaped conductive coating 22 may be formed so that there is a cut in the non-periphery of the inner surface of the hermetic container 12 so as to partially surround the pair of discharge electrodes 14 and 14.

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

Further, the conductive material powder composing the conductive coating 22 is mixed in a solvent and a resin adhesive, thereby producing an ink-like dispersion liquid in which the conductive material powder is mixed. In this embodiment, carbon-based powders such as graphite, carbon black, and carbon nanotube are used as the conductive material.
Examples of the solvent include alcohol solvents, methyl ethyl ketone solvents, acetone solvents, and aqueous solvents.
Moreover, as said resin adhesive, the adhesive of a cellulose resin, an acrylic resin, an epoxy resin, and a urethane resin corresponds.

  The ink-like dispersion liquid is supplied to the dispenser 26, and a small amount of the dispersion liquid is ejected from the tip of the needle 28 of the dispenser 26 so that the droplet of the dispersion liquid 30 adheres to the tip of the needle 28 [see FIG.

Next, as shown in FIG. 3A, the tip of the needle 28 of the dispenser 26 is inserted into the glass tube 24 by a predetermined distance from an oblique direction, and the droplet of the dispersion liquid 30 is brought into contact with the inner surface of the glass tube 24.
Next, in a state where the droplets of the dispersion liquid 30 are in contact with the inner surface of the glass tube 24, 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). Rotate the glass tube 24.
As a result, as shown in FIG. 3 (b), the dispersion 30 is applied to the inner surface of the glass tube 24 in a strip shape. At this time, if the glass tube 24 is rotated by 360 degrees or more, the dispersion 30 can be applied in a strip shape without any breaks over the entire inner surface of the glass tube 24.
Thereafter, the dispersion 30 is dried, whereby the conductive coating 22 of the discharge surge absorbing element 10 is formed.

  Next, a pair of discharge electrodes 14, 14 to which one ends of the lead terminals 18, 18 are connected are inserted into the glass tube 24 from one end opening in a state where the discharge electrodes 14, 14 are held in parallel with a predetermined gap therebetween, and the lead The other ends of the terminals 18 and 18 are accommodated so as to protrude outward from the glass tube.

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

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

The above manufacturing method of the present invention includes a process for preparing and preparing a trigger discharge member 004 such as a conventional discharge type surge absorbing element 001, and a process for 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 manufacturing method of the present invention, a droplet of the dispersion liquid 30 obtained by mixing a conductive material powder in a solvent and a resin adhesive is applied to the inner surface of the glass tube 24 on which the airtight container 12 is based. After the contact, the conductive coating 22 disposed on the inner surface of the airtight container 12 can be formed by a simple process of rotating the glass tube 24 and applying the dispersion 30 to the inner surface of the glass tube 24 in a strip shape. .

When a surge is applied to the discharge type surge absorbing element 10 having the above-described configuration via the lead terminals 18, 18, electrons are formed between the conductive coating 22 formed on the inner surface of the hermetic container 12 and the discharge electrodes 14, 14. Is released and a trigger discharge occurs.
Next, this trigger discharge shifts to glow discharge due to the priming effect of electrons. Then, the glow discharge is transferred to the discharge gap 16 due to an increase in surge current, and is further transferred to 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 and 14, the trigger discharge between the conductive coating 22 and each of the discharge electrodes 14 and 14 is generated over a wide range. be able to.
In particular, as in the present embodiment, when the strip-shaped conductive coating 22 is formed on the entire inner surface of the hermetic 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. It is.

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

  In addition, since the conductive coating 22 is formed on the inner surface of the hermetic container 12 made of glass, the amount of electrode material deposited on the conductive coating 22 is reduced because the discharge electrodes 14 and 14 are sputtered and scattered by the impact during discharge. As a result, it is possible to realize the discharge-type surge absorbing element 10 having a long life by suppressing deterioration of insulation and instability of the discharge start voltage.

FIG. 4 shows the relationship between the number of surges applied (5000 times) and the insulation resistance (MΩ) in the discharge type surge absorbing element 10 (three pieces) according to the present invention and the conventional discharge type surge absorbing element 001 (three pieces). It is a graph to show. The applied impulse current waveform is 8/20 μs-100 A.
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 rapidly decreases from the time when the number of times of application exceeds 2000 times, resulting in insulation deterioration. In contrast, in the case of the discharge type surge absorbing element 10 of the present invention (graph A in FIG. 4), there is no significant change in the insulation resistance until the number of times of application is 3000 times, and it exceeds 3000 times. However, since the decrease in the insulation resistance is gradual, the deterioration of the insulation is suppressed as compared with the conventional discharge type surge absorbing element 001, and a long life is realized.

FIG. 5 is a graph showing the relationship between the impulse discharge start voltage (kV) and the number of surges applied (300 times) in the discharge surge absorbing element 10 according to the present invention and the conventional discharge 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 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 in FIG. 5), the impulse discharge start voltage varies greatly as the number of times of application increases and is unstable. 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 a long life is realized.

It is a schematic sectional drawing which shows the discharge type surge absorption element which concerns on this invention. It is an AA expansion schematic sectional drawing 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 frequency | count of a 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 frequency | count 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 partial expanded sectional view which shows the discharge electrode and trigger discharge member of the conventional discharge type surge absorption element. It is XX schematic sectional drawing of FIG.

10 Discharge type surge absorber
12 Airtight container
14 Discharge electrode
16 Discharge gap
18 Lead terminal
20 coating
22 Conductive coating
24 glass tubes
26 Dispenser
28 needle
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;
Attaching the droplet of the dispersion to the tip of the dispenser;
A step of inserting the tip of the dispenser into a long and narrow glass tube having both ends opened at a predetermined distance, and bringing a droplet of the dispersion into contact with the inner surface of the glass tube;
A process of forming a conductive film by applying the dispersion liquid to the inner surface of the glass tube by rotating the glass tube in a state where the droplets of the dispersion liquid are in contact with the inner surface of the glass tube;
A plurality of discharge electrodes connected to one end of the lead terminal are inserted into the glass tube through one end opening while being held 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
A step of heating and melting the vicinity of one end opening of the glass tube, crushing and sealing the melted portion inward, and forming a sealing portion;
A step of sealing hermetically by filling the glass tube with a discharge gas and then heating and melting and sealing the other end opening of the glass tube;
A method of manufacturing a discharge type surge absorbing element, comprising: The method for manufacturing a discharge type surge absorbing element according to claim 1, wherein the conductive material powder is a carbon-based powder.

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