JP3164781B2 - Discharge type surge absorbing element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge type surge absorbing element which absorbs an overvoltage such as a surge by utilizing a discharge phenomenon in a discharge gap enclosed in an airtight container, and more particularly to a discharge type surge absorber after a surge disappears. The present invention relates to a discharge type surge absorbing element that can be effectively prevented.

[0002]

2. Description of the Related Art Conventionally, in order to protect an electronic circuit element from a surge of a transient abnormal voltage or an induced lightning which invades an electronic device, a discharge type surge absorption utilizing a discharge phenomenon in a discharge gap sealed in an airtight container. An element is used. As an example, the discharge type surge absorbing element 50 shown in FIG. 4 has lead terminals 58, 58 at the lower ends of a pair of discharge electrodes 56, 56 each having a round rod-shaped electrode base 52 with an emitter layer 54 attached to the surface thereof. Are connected in parallel to each other with a predetermined discharge gap 60 therebetween, and argon (Ar), neon (Ne), and helium (H) are placed in an airtight container 62 formed by processing a glass tube.
e), a discharge gas made of an inert gas such as xenon (Xe) is sealed together, and the lead terminals 58, 58 are led out through the lower end sealing portion 62a of the airtight container 62.

As shown in FIG. 5, for example, a discharge type surge absorbing element 50 is provided between a pair of power supply lines L1 and ground G, and between L2 and ground G, which are connected to a protected circuit 64.
They are inserted and connected via lead terminals 58, 58, respectively. Then, between the power line L1 and the ground G or L2
When a surge such as an induced lightning is applied between the ground G, an arc discharge is generated through the glow discharge in the discharge gap 60, and the surge is generated by the large current of the arc discharge.
It will be escaped to the side.

[0004]

When the discharge type surge absorbing element 50 is connected to the power lines L1 and L2, as shown in FIG. Because the voltage between both ends of the absorbing element 50 rapidly drops to below the peak voltage of the power line,
The so-called continuation, in which the discharge continues due to the power supply voltage even after the surge has left, occurs, and the continuation current may overheat the discharge-type surge absorbing element 50, causing a risk of melting short-circuit or burning of the element. Conventionally, to prevent this follow-up current, an element having a current limiting function such as a resistor 66 shown in FIG. 5 or a varistor (not shown) is separately connected, or an element having a current interrupting function such as a fuse is connected. Had been
This causes a complicated circuit configuration and complicated connection work. In addition, if an element with a current interrupt function such as a fuse is connected, once the fuse is blown and the line is opened, it is necessary to reconnect a new fuse to resume use of the electronic device. There was a problem in that the recovery work was troublesome

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and effectively prevents the generation of a subsequent current without separately connecting elements having a current limiting function and a current interrupting function. It is an object of the present invention to realize a discharge-type surge absorbing element that can perform the operation.

[0006]

In order to achieve the above object, a discharge-type surge absorbing element according to the present invention comprises a plurality of discharge electrodes arranged to face each other with a discharge gap therebetween, and the discharge electrodes are disposed together with a discharge gas in an airtight container. In a discharge type surge absorbing element formed by leading a lead terminal connected to the discharge electrode outside the airtight container, an oxygen ion conductor layer is formed on the surface of at least one discharge electrode. I do.
Examples of the oxygen ion conductor constituting the oxygen ion conductor layer include GdCaCr ₂ O ₃ and LaSrMn.
O ₃ , ZrO _{2 (0.92)} Y ₂ O _{3 (0.08)} , CeO _{2 (0.8)} Gd ₂
O _{3 (0.2)} applies.

The oxygen ion conductor has a property of releasing oxygen when its temperature rises. When a surge is applied to the discharge type surge absorbing element of the present invention and the surge is absorbed by the arc discharge, the temperature of the discharge electrode sharply rises due to heat generated by the arc discharge. The temperature of the ionic conductor layer also rises, releasing oxygen. As a result, oxygen will be mixed into the hermetic container, which was only inert gas, and the discharge sustaining voltage of the discharge type surge absorbing element will increase, which easily exceeds the peak voltage of the power supply line. You can do it. When the surge is discharged and the discharge electrode cools down and the temperature of the oxygen ion conductor layer formed on the surface of the discharge electrode decreases, the released oxygen returns to the oxygen ion conductor layer, and the inside of the hermetic container is again damaged. Since only the active gas is used, the discharge type surge absorbing element automatically returns to the original state.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view showing a first discharge type surge absorbing element 10 according to the present invention. The first discharge type surge absorbing element 10 has a pair of discharge electrodes 12 and 12 formed by processing a metal such as nickel having excellent conductivity into an elongated round bar, and has a dumet wire (copper-coated iron-nickel alloy wire) at the lower end. ) And 42-6 alloy wires, etc., are connected, and the two discharge electrodes 12, 12 are arranged in parallel at a predetermined distance to form a discharge gap 16, which is connected to the glass tube. Argon (Ar), neon (Ne), helium (He),
It is sealed together with a discharge gas composed of an inert gas such as xenon (Xe), and the lead terminals 14, 14 of the discharge electrodes 12, 12 are passed through the lower end sealing portion 18a of the hermetic container 18 and led out to the outside. Has a basic configuration.

An oxygen ion conductor layer 20 made of GdCaCr ₂ O ₃ is formed on the surfaces of the pair of discharge electrodes 12, 12. The oxygen ion conductor constituting the oxygen ion conductor layer 20 includes the above-mentioned GdCaCr ₂
In addition to O ₃ , LaSrMnO ₃ , ZrO _{2 (0.92)} Y ₂ O
_{3 (0.08)} or CeO _{2 (0.8)} Gd ₂ O _{3 (0.2)} .

The first discharge type surge absorbing element 10 has an operating voltage (DC discharge starting voltage) of about 200 V, and as shown in FIG. Between the power line L1 and the ground G and between the L2 and the ground G via lead terminals 14 and 14, respectively. Thus, the power supply line L1-ground G
When a surge such as an induced lightning that exceeds the rated voltage of the discharge type surge absorbing element 10 is applied to the discharge gap 16 or between L2 and G, an arc discharge is generated in the discharge gap 16 via a glow discharge. Absorption of the surge is realized through the large current.

GdCaCr ₂ O ₃ constituting the oxygen ion conductor layer 20 formed on the surface of the discharge electrodes 12 of the first discharge type surge absorbing element 10 has a valence of Cr of Cr when the temperature rises. ^{From 3+} to Cr ⁴⁺ , resulting in GdC
aCr ₂ O ₃ migrates to GdCaCr ₂ O ₂ + O to release oxygen, while when the temperature decreases, the valence of Cr changes from Cr ⁴⁺ to Cr ³⁺ again, and the state of GdCaCr ₂ O ₂ + O changes from the original state. It returns to GdCaCr ₂ O ₃ . Accordingly, when a surge is applied to the first discharge type surge absorbing element 10 and the surge is absorbed by the arc discharge, the temperature of the discharge electrodes 12, 12 rises sharply due to the heat generated by the arc discharge. As a result, the temperature of the oxygen ion conductor layer 20 also rises, and oxygen is released instantaneously. This released oxygen is
As a result of mixing into the hermetic container 18 containing only the inert gas, the discharge sustaining voltage rises to 400 V to several kV and becomes higher than the peak voltage of the power supply line, so that it is possible to prevent the subsequent flow after the surge. Also, when the surge
When the temperature is lowered by cooling the second and the second 12, the temperature of the oxygen ion conductive layer 20 is also lowered, and the released oxygen returns to the oxygen ion conductive layer 20, and the inside of the hermetic container 18 becomes only the inert gas again. Therefore, the discharge type surge absorbing element 10 automatically returns to the original state.

FIG. 2 is a longitudinal sectional view showing a second discharge type surge absorbing element 30 according to the present invention. The second discharge-type surge absorbing element 30 includes a pair of cap-shaped discharge electrodes 34 made of nickel or the like provided at both ends of a cylindrical body 32 made of an insulating material.
34 are fitted together and hermetically sealed between them via a sealing material 36 to form a substantially drum-shaped hermetic container 38. Each cap-shaped discharge electrode 34,
A discharge gap 40 is formed between the inner end portions 34a, 34a of the inner surface 34, and the outer surface recesses 34b, 34
b, lead terminals 42, 42 are connected to the airtight container 38, respectively, and argon (Ar), neon (Ne),
It basically has a structure in which a discharge gas made of an inert gas such as helium (He) or xenon (Xe) is sealed. Then, an oxygen ion conductor layer 44 of GdCaCr ₂ O ₃ is formed on the surface of the inner end portions 34a, 34a of the cap-shaped discharge electrodes 34, 34, similarly to the first discharge type surge absorbing element 10. Is what is being done.

[0013] Even in the second discharge type surge absorbing element 30, when a surge is applied and the surge absorption by the arc discharge is started, heat generated by the arc discharge causes the cap-shaped discharge electrodes 34, 34 to generate heat. The temperature of the inner end portions 34a, 34a rises rapidly, and as a result, the temperature of the oxygen ion conductive layer 44 also rises, and oxygen is released instantaneously. This released oxygen is
As a result of mixing in the hermetic container 38 containing only the inert gas, the discharge sustaining voltage rises and becomes equal to or higher than the peak voltage of the power supply line, so that a subsequent flow after the surge can be prevented. Also, the surge discharges and the cap-shaped discharge electrode 3
When the inner surface tips 34a, 34a of the 4, 34 cool and the temperature decreases, the temperature of the oxygen ion conductor layer 44 also decreases, the released oxygen returns to the oxygen ion conductor layer 44, and the inside of the airtight container 38 Discharge type surge absorbing element because only inert gas is used again
30 automatically returns to its original state.

In the first surge absorber 10 and the second surge absorber 30, after the surge has been released, the released oxygen returns to the oxygen ion conductor layers 20, 44, and the airtightness is maintained. Since it takes some time for the inside of the containers 18 and 38 to contain only the inert gas again, when a surge may be applied frequently, as shown in FIG. Between the ground and the ground G, and between L2 and the ground G, respectively.
Two or more 0s and 30s may be inserted and connected.

The first discharge type surge absorbing element 10
In the second discharge type surge absorbing element 30, the oxygen ion conductor layers 20, 44 are formed on both of the pair of discharge electrodes 12, 12 or both of the pair of cap-shaped discharge electrodes 34, 34. But not limited to this. That is,
As long as enough oxygen can be released to raise the discharge sustaining voltage of the discharge type surge absorbing element to a level higher than the peak voltage of the power supply line, only one of the discharge electrodes 12 and one of the cap-shaped discharge electrodes 34 can be discharged. Oxygen ion conductor layer 20, 44
May be formed.

[0016]

In the discharge type surge absorbing element according to the present invention, since the oxygen ion conductor layer is formed on the surface of the discharge electrode, the temperature of the discharge electrode rapidly rises due to heat generated by arc discharge at the time of surge absorption. As a result, the temperature of the oxygen ion conductor layer also rises and oxygen is released, and the released oxygen is mixed into the hermetic container, which was only inert gas. Since the voltage can be equal to or higher than the peak voltage of the line, it is possible to effectively prevent the following current without separately connecting an element having a current limiting function or a current interrupting function.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first discharge type surge absorbing element according to the present invention.

FIG. 2 is a sectional view showing a second discharge type surge absorbing element according to the present invention.

FIG. 3 is a circuit diagram showing a case where a plurality of discharge type surge absorbing elements according to the present invention are connected.

FIG. 4 is a front view showing a conventional discharge type surge absorbing element.

FIG. 5 is a circuit diagram showing a connection example of a first discharge type surge absorbing element and a conventional discharge type surge absorbing element.

[Explanation of symbols]

 10 First discharge type surge absorbing element 12 Discharge electrode 14 Lead terminal 16 Discharge gap 18 Hermetic container 20 Oxygen ion conductor layer 30 Second discharge type surge absorbing element 32 Cylindrical body 34 Cap-shaped discharge electrode 36 Sealing material 38 Airtight Vessel 40 Discharge gap 42 Lead terminal 44 Oxygen ion conductor layer

Claims (2)

(57) [Claims] 1. A plurality of discharge electrodes are arranged opposite to each other with a discharge gap therebetween, sealed with a discharge gas in an airtight container, and lead terminals connected to the discharge electrodes are led out of the airtight container. A discharge type surge absorbing element, wherein an oxygen ion conductor layer is formed on a surface of at least one discharge electrode. 2. The method according to claim 1, wherein the oxygen ion conductive layer is formed of GdCaC.
r ₂ O ₃ , LaSrMnO ₃ , ZrO _{2 (0.92)} Y
_2. The discharge type surge absorbing element according to claim 1, wherein the element is made of any one of ₂ O _{3 (0.08)} and CeO _{2 (0.8)} Gd ₂ O _{3 (0.2)} .