JPH054231Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is used when connected between electronic equipment and a power source, and is used to prevent surges from entering the equipment through a discharge gap sealed in an airtight container. This invention relates to a discharge-type surge absorption element that absorbs electricity through a discharge phenomenon, and in particular to a discharge-type surge absorption element with a safety mechanism that improves safety in the event of a failure by devising the container structure to create an open failure mode. .

[Prior Art] Conventionally, a seed discharge type surge absorbing element 10, widely known as an arrester, has a pair of bar-shaped discharge electrodes 2, 2 made of Ni or the like arranged substantially parallel to each other, as shown in FIG. A discharge gap 4 is formed between the discharge electrodes 2, 2, and this is sealed together with a discharge gas such as a rare gas in an airtight container 5 made of a glass bulb. 3 is connected and led out of the airtight container 5.

The discharge type surge absorbing element 10 is used by being connected between a circuit of an electronic device and a power source,
If a surge such as dielectric lightning is applied to this,
A discharge occurs in the discharge gap, absorbing the surge, and protecting the electronic equipment from the surge.

[Problems to be solved by the invention] The above-mentioned discharge type surge absorption element absorbs surges by arc discharge in the discharge gap, and therefore can absorb fairly large surges, but if a surge significantly exceeding the rated capacity is applied, the energy may melt the discharge electrode, causing a short circuit. Also, even if the surge is within the rated capacity, if it is applied repeatedly over a long period of time, spatter material from the discharge electrode may accumulate on the inner wall of the airtight container, causing a short circuit.

As mentioned above, when the discharge type surge absorption element fails in the short circuit mode, an excessive short circuit current flows into the surge absorption element and melts it, eventually causing the circuit board on which the discharge type surge absorption element is mounted to fail. The heat generated by the element may lead to combustion, which may cause burnout to the surrounding area.

This invention was devised in view of the above points,
Safety equipment equipped with a mechanism that can cut off the overcurrent and prevent burnout accidents when an overcurrent flows due to a surge that significantly exceeds the rating, or when a short circuit current due to spatter material becomes excessive. The aim is to realize a discharge type surge absorption element with a mechanism.

[Means for solving the problem] In order to achieve the above object, the discharge type surge absorbing element with safety mechanism according to the present invention has a pair of discharge electrodes arranged facing each other at a predetermined interval, A discharge type surge absorption element with a safety mechanism, comprising: a discharge type surge absorption element formed by forming a discharge gap and encapsulating the same in an airtight container; and a safety member disposed in contact with the surface of the airtight container. Being an element,
When the discharge-type surge absorption element becomes heated due to overcurrent, there is a temperature difference between the airtight container and the safety member that is sufficient to destroy the airtight container due to thermal distortion. The present invention is characterized in that the specific heat of the material constituting the security member is set to be larger than the specific heat of the material constituting the airtight container so that the following occurs.

[Function] If a surge that significantly exceeds the rating is applied to the discharge type surge absorbing element with safety mechanism, and an overcurrent flows through the element due to the application of the surge, an arc discharge occurs in the discharge gap. A large amount of heat is generated, and this heat heats the airtight container, causing its temperature to rise rapidly. On the other hand, since the safety member has a larger specific heat than the airtight container, almost no temperature increase is observed, and a temperature difference occurs between the airtight container and the safety member. Then, thermal distortion occurs due to this temperature difference, and the airtight container is destroyed at the portion where the safety member is in contact. As a result, the discharge in the discharge gap is stopped and the overcurrent is cut off. Additionally, when a short circuit occurs due to spattered materials, if the short circuit current becomes excessive, a large amount of joule heat is generated, and as mentioned above, the airtight container is destroyed, the conductive path is severed, and the overcurrent is interrupted. be done.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a perspective view of a discharge type surge absorbing element with a safety mechanism according to an embodiment of the present invention. In the figure, the discharge type surge absorbing element 1 with safety mechanism uses BaCO ₃ , BaO, etc. on the surface of a metal with good discharge characteristics such as Ni.
A pair of rod-shaped discharge electrodes 2, 2 formed by covering with an emitter material such as AI ₂ O ₃ is connected to one end of each of the lead wires 3, 3 made of a composite wire, and the lead wires 3, 3 are made to face each other substantially in parallel to perform the above-mentioned discharge. A discharge gap 4 is formed between the electrodes 2, 2, and this is further sealed in an airtight container 5 together with a discharge gas mainly composed of a rare gas such as Ne, He, Ar, etc. or an inert gas such as nitrogen gas. have.

The airtight container 5 is formed by heating and crushing one end of a glass tube to fix the lead wires 3, 3 and sealing the other end, and as shown in FIG. As shown in FIG. 1B, a ring-shaped safety member 6 is tightly wound around the vicinity of the crushed portion 5b.

The safety member 6 is made of a material having a specific heat larger than that of the glass tube constituting the airtight container 5. The difference in specific heat between the two means that when the element heats up due to overcurrent, the temperature difference between the airtight container and the safety member is sufficient to destroy the airtight container 5 due to thermal distortion. It is set so that

[Effects of the invention] As detailed above, the discharge type surge absorbing element with a safety mechanism of the present invention has an airtight structure in the area where the safety member is in contact when the element becomes overheated due to overcurrent. Since the container is destroyed and the overcurrent is cut off, burnout accidents can be prevented. Further, the above-mentioned safety mechanism can be easily formed by simply adding a simple member to the airtight container of the conventional discharge type surge absorbing element, and has high practical value.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and FIG.
1B is a perspective view of the ring-shaped security member wound around the sealing portion, FIG. 1B is a perspective view of the ring-shaped security member wound near the crushing portion, and FIG. It is a perspective view of a conventional example. 1...discharge type surge absorption element with safety mechanism, 2,
2...Discharge electrode, 4...Discharge gap, 5...Airtight container, 6...Security member.

Claims (1)

[Claims for Utility Model Registration] (1) A discharge-type surge absorber in which a pair of discharge electrodes are arranged facing each other at a predetermined interval to form a discharge gap between the discharge electrodes, and this is sealed in an airtight container. A discharge type surge absorbing element with a safety mechanism, comprising an element and a safety member disposed in contact with the surface of the airtight container, wherein the discharge type surge absorbing element generates heat due to the application of an overcurrent. The specific heat of the material constituting the security member is adjusted so that, when the condition occurs, a temperature difference sufficient to destroy the airtight container due to thermal distortion occurs between the airtight container and the security member. A discharge-type surge absorption element with a safety mechanism, characterized in that the specific heat is set higher than the specific heat of the material constituting the airtight container. (2) A utility model registration request characterized in that the airtight container is made of a glass tube, the security member has a ring shape, and the security member is wound around the glass tube. A discharge type surge absorbing element with a safety mechanism according to item 1.