JPH0773072B2 - Surge absorber - Google Patents

Description

TECHNICAL FIELD The present invention relates to a surge absorbing element used to protect from surge voltage transiently applied to various electronic circuits.

(B) Conventional Technology As a conventionally known surge absorbing element, there is one shown in FIG. This surge absorbing element has a columnar insulator 21 with a relative permittivity larger than 1, for example, alumina magnetism.
A conductive thin film 22 is formed on the surface of the conductive thin film 22 and the conductive thin film 22 is divided into two parts by a circumferential groove 23 having a width of 200 μm or less. Electrodes 24 and 24 are provided at both ends of the divided conductive thin films 22 and 22, respectively. The lead wires 25 and 25 are connected to the electrodes 24 and 24, respectively, and the insulator 21, the electrodes 24 and 24, and the lead wires 25 and 25 are sealed with a sealing material 26 such as glass. The inside of the sealing material 26 is filled with an inert gas.

In this surge absorbing element, when a voltage higher than a predetermined value is applied between the lead wires 25, 25, electrons are emitted from the negative voltage side of the circumferential groove 23, and the electrons cause the positive voltage side and negative voltage side of the circumferential groove 23. A creeping discharge is generated between the
It shifts to the arc discharge between 24 and 24, and the surge voltage is absorbed by this arc discharge.

(C) Problems to be Solved by the Invention In the conventional surge absorbing element, as described above, the conductive thin film 22 is formed on the surface of the insulator 21, and the circumferential groove 23 that divides the surge absorbing body into two is formed. In addition, the electrodes 24, 24 are provided at both ends, which is used as a sealing material 26 such as glass.
Since it is sealed with, the structure becomes complicated, and there is a limit to making the internal element body 21 small in particular, and accordingly, it is also possible to correspondingly reduce the length of the surge absorber using the insulator as a base. There was a limit, and it was not possible to miniaturize the device.

In addition, the circumferential groove 23 and the electrodes 24, 24 require complicated assembly in order to ensure the quality of the element, which causes a problem of high cost.

In view of the above, it is an object of the present invention to provide a surge absorbing element that is downsized and can be manufactured at low cost.

(2) Means and Actions for Solving Problems The surge absorbing element of the present invention has a slug having a lead wire at the outer end, a needle-shaped electrode having a tip opposed to the inner end surface of the slug, and the needle. An electrode holding part for leading out the lead wire of the needle-shaped electrode to the outside and holding the needle-shaped electrode, and forming an inner chamber part surrounding the slug, the needle-shaped electrode and the electrode holding part, and an inert gas in the inner chamber part Between the inner end surface of the slug and the tip of the needle-shaped electrode by energizing between the lead wires in a contact state between the sealing material that seals the inner end surface of the slug and the tip of the needle-shaped electrode. It is composed of a microgap of 10 to 100 μm formed between them.

In this surge absorbing element, when a surge voltage is applied between the lead wires, discharge is started in the micro gap between the needle electrode and the inner end surface of the slug, and the surge voltage is absorbed.

(E) Examples Hereinafter, the present invention will be described in more detail with reference to Examples.

FIG. 1 is a sectional view of a surge absorbing element showing an embodiment of the present invention. This surge absorbing element includes a slug 1, a needle-shaped electrode 2, an electrode holding portion 3, a microgap 4 formed between the inner end surface of the slug 1 and the tip of the needle-shaped electrode 2, and a glass-like sealing. The material 5 is provided.

The slag 1 also serves as one of the electrodes, has a cylindrical shape in which Cu is formed around a base body made of Ni and Fe, and has a lead wire 6a at its outer end.

The needle electrode 2 is made of tungsten or the like and has a bent portion, but it may be a straight electrode. The needle electrode 2 is welded to the tip of the lead wire 6b in advance. The electrode holding portion 3 is made of glass and holds the lead wire 6b, and thus holds the needle electrode 2. The encapsulating material 5 surrounds the slug 1, the needle-shaped electrode 2, and the electrode holding portion 3 and hermetically covers them. A space 7 is formed by the sealing material 5, the slag 1 and the inner end surface of the electrode holding portion 3, and the space 7 is filled with an inert gas such as argon, helium, neon, or nitrogen.

The micro gap 4 is a minute value of 10 to 100 μm,
As shown in FIG. 2, this is initially sealed with a sealing material 5 in a state where the tip of the needle-shaped electrode 2 is in pressure contact with the inner end surface of the slug 1, and 1,000 to 2,000 are passed through the lead wires 6a and 6b. An impact current of about amperes is applied and spot welding is performed by the electric resistance of the contact portion.

In the surge absorbing element configured as described above, when a voltage higher than the specified is applied between the lead wires 6a and 6b, the micro gap 4 formed between the inner end surface of the slug 1 and the tip of the needle electrode 2 Discharge starts and the surge voltage is absorbed.

(F) Effect of the Invention According to the present invention, since the electric discharge is generated in the microgap of 10 to 100 μm formed between the inner end surface of the slag and the tip of the needle-shaped electrode, the conventional surge absorption element An internal element consisting of a simple resistor element and peripheral grooves and electrodes provided in the resistor element is not required, and ultra miniaturization can be realized. Further, since the internal element is unnecessary, an inexpensive surge absorbing element can be obtained accordingly.

[Brief description of drawings]

FIG. 1 is a sectional view of a surge absorbing element showing an embodiment of the present invention, FIG. 2 is a sectional view for explaining formation of a microgap of the surge absorbing element, and FIG. 3 is a conventional surge absorbing element. It is sectional drawing which shows an absorption element. 1: Slug, 2: Needle-shaped electrode, 3: Electrode holder, 4: Microgap 5: Sealing material, 6a ・ 6b: Lead wire.

Claims (1)

[Claims] 1. A slug having a lead wire at its outer end, a needle-shaped electrode having a tip opposed to the inner end face of this slug, and a lead wire of this needle-shaped electrode being led to the outside and holding the needle-shaped electrode. An electrode holding part, a slug, a needle-shaped electrode and a sealing material that surrounds the electrode holding part to form an inner chamber part and seals an inert gas in the inner chamber part, and an inner end surface of the slug and the Surge absorption consisting of a microgap of 10 to 100 μm formed between the inner end surface of the slug and the tip of the needle electrode by energizing the lead wires in a state of contact with the tip of the needle electrode. element.