JPS62232881A - Surge absorber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a surge absorption element used to protect various electronic circuits from surge voltages transiently applied.

(B) Prior Art A conventionally known surge absorbing element is shown in FIG. 3. This surge absorbing element is made of a cylindrical insulator 2, such as alumina porcelain, whose dielectric constant is greater than 1.
A conductive thin film 22 is formed on the surface of the conductive thin film 22, and the conductive thin film 22 is further divided into two parts by a circumferential groove 23 having a width of 20,011 m or less, and electrodes 24, 24 are provided at both ends of the divided conductive thin film 22, 22, respectively. A lead wire 25.25 is connected to each electrode 24.24, and a sealing material 2G such as glass is connected to the electrode 24.24.
The insulator 21, electrodes 24, 24, and lead wires 25, 25 are sealed. The inside of the sealing material 26 is configured to be filled with an inert gas.

In this surge absorbing element, when a predetermined voltage or more is applied between the lead wires 25 and 25, electrons are emitted from the negative voltage side of the circumferential groove 23, and these electrons cause the positive voltage side and the negative voltage side of the circumferential groove 23 to be emitted. A creeping discharge is generated between the electrodes 24 and 24, and then this creeping discharge shifts to an arc discharge between the electrodes 24 and 24, and the surge voltage is absorbed by this arc discharge.

(c) Problems to be Solved by the Invention As mentioned above, the conventional surge absorbing element has an insulator 21
A conductive thin film 22 is formed on the surface of the surge absorber, a circumferential groove 23 is formed to divide the surge absorber into two, and CJ! i
<24.24 is provided and this is sealed with a sealing material 26 such as glass, so the structure is complicated and there is a limit to reducing the size of the insulator 21. There was a problem with miniaturization.

In addition, the circumferential groove 23 and electrodes 24 and 24 are designed to ensure the quality of the element.
There was a problem that complicated assembly was required and the cost was high.

Furthermore, if the formation precision of the electrodes 24, 24 is poor, the discharge starting voltage varies from product to product, which causes a large variation in the operating voltage for surge absorption, resulting in a problem of lowering product quality.

In view of the above, it is an object of the present invention to provide a surge absorption element that is miniaturized, can be manufactured at low cost, and has high quality.

(d) Means and operation for solving the problems The surge absorbing element of the present invention includes a pair of resistor elements, an insulating ring interposed at the inner end of the pair of resistor elements, and the resistor. The area of the inner end surface is larger than that of the element body, and the outer end has a lead wire,
A pair of slugs whose inner ends are pressed against the outer end of the resistor element, and an inert gas surrounding the resistor element and the slug, and in the space formed between the resistor element and the slug. and a sealing material for sealing.

In this surge absorbing element, when a surge voltage is applied between the lead wires, a discharge is started between the inner end surfaces of the resistor body and the inner end surface of the slug, which are spaced apart from each other via an insulating ring with a minute thickness. Surge voltage is absorbed.

(E) Examples The present invention will be explained in more detail with reference to Examples below.

FIG. 1 is a sectional view of a surge absorbing element showing an embodiment of the present invention. This surge absorbing element includes a pair of resistive elements 1a and 1b that absorb surges, an insulating ring 2, a pair of slugs 3a and 3b, and a sealing material 4 such as glass.

The resistive elements 1a and 1b each have a cylindrical base made of an insulating material such as mullite porcelain, alumina porcelain, or ceramics, and coated with carbon, metal oxide, or T on the outer peripheral surface.
A conductive film of nitride such as aN is formed. An insulating ring 2 having a thickness of several tens of micrometers is sandwiched between the resistive elements 1a and 1b. As shown in FIG. 2, the diameter of the insulating ring 2 is set to be approximately the same as the diameter of the resistor elements 1a and lb. Glass or ceramics is used as the insulating ring material.

The slugs 3a, 3b also serve as electrodes, and are configured in a cylindrical shape with a larger diameter than the resistor elements 1a, lb, and have lead wires 5a, 5b at their outer ends, and their inner end faces are the resistor elements 1a, 1b. The outer ends of 1b are pressed together.

The slugs 3a and 3b are constructed by forming Cu11 on the circumferential surface of a base made of Ni+Fe. The sealing material 4 includes the resistor elements 1a and 1b, the insulating ring 2, and the slugs 3a and 3b.
The outer cover is airtight. This sealing material 4 and slags 3a, 3
Inner end surface of b, resistor element 1a, 1b71 discontinuous 8 (ring 2
A cavity 6 is formed on the outer peripheral surface of the cavity 6, and argon,
It is filled with inert gas such as helium, neon, nitrogen, etc.

In this embodiment surge absorbing element, lead wires 5a, 5
When a voltage higher than the specified voltage is applied between the resistor element 1a and
The discharge starts in a small gap between the parallel inner end surfaces of the slugs 3a and 1b, and as the current value increases further, the discharge shifts to a full-scale discharge between the inner end surfaces of the slugs 3a and 3b.

(f) Effects of the Invention According to the present invention, since a pair of resistor elements are caused to discharge with their inner end surfaces facing parallel to each other with a small gap through an insulating ring, it is not necessary to provide a conventional circumferential groove. Since the length of the resistor element can be shortened, a small-sized surge absorbing element can be obtained. In addition, since the discharge occurs between the parallel opposed electrode surfaces, a stable discharge starting voltage can be obtained, so that variations among products can be reduced and high quality products can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a surge absorbing element showing an embodiment of the present invention, FIG. 2 is an exploded perspective view of the resistor body and insulating ring of the same surge absorbing element, and FIG. 3 is a conventional surge absorbing element. FIG. 3 is a cross-sectional view showing a surge absorbing element. 1a/1b: Resistor element, 2: Insulating ring, 3a/3b
Nisslug, 4: Sealing material, 5a and 5b; Lead wire. Patent applicant ROHM Co., Ltd. agent
Patent Attorney Shigeru Nakamura Shin Figure 1 1 o-ib: t+'<, tit, i 2: b color 4
i'J': '7' 3a/3 or slug 4: No. 5a/5 or lead edge

Claims (1)

[Claims] (1) A pair of resistor elements, an insulating ring interposed between the inner ends of the pair of resistor elements, the inner end surface area of which is larger than the resistance element body, and a lead wire at the outer end. a pair of slugs, the inner ends of which are pressed against the outer ends of the resistor element; A surge absorption element consisting of a sealing material that seals in active gas.