JPH02230679A - Discharge tube - Google Patents

Abstract

PURPOSE:To provide a stable discharge voltage characteristic regardless of a change in discharge frequency by using an electrode consisting of a laminate metallic body which contains at least a surface thin layer and a base layer as a cathode. CONSTITUTION:A surface thin layer is installed on the surface of an electrode. Such an electrode may be a 2-layer structure or a 3-layer structure, or of a structure of multi-layer more in layer than them. The surface thin layer is formed on base layer by means of plating, etc., and its thickness of such a structure is used for a cathode; however, it may be used for a cathode 1 and an anode 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a discharge tube for voltage control, particularly to a discharge tube used for series gas in an ignition device for an automobile engine or the like.

[Conventional technology]

Ignition systems in automobile engines, etc., supply high voltage to the spark plug to generate sparks, but in order to accurately control the ignition timing, a so-called series gap is used in which a discharge gap is provided in series with the spark plug. An igniter with a igniter is used. To form such a series gap, a discharge tube with an inert gas sealed inside the tube and electrodes provided at both ends of the tube is used. For example, as shown in Fig. It is known that a metal wire electrode b coated with zirconium nitride is sealed and filled with a pressurized mixed gas of nitrogen and hydrogen.

Furthermore, in such a discharge tube, the discharge starting voltage needs to be high to a certain extent, but if the electrode spacing is widened for this purpose, the discharge sustaining voltage also increases, which increases the loss of energy that should be supplied to the spark plug. There is also the problem of increased wear and tear and shortened lifespan.

In order to solve this problem, the present inventors have researched an improvement in which the opposing surfaces of a pair of electrodes are made non-sharp, thereby increasing the discharge voltage and lowering the discharge sustaining voltage. They found that the accuracy of the discharge voltage could be improved by at least providing a large number of uneven parts on the surface of the cathode, but there is no solution to the problem of the discharge voltage decreasing as the discharge frequency increases. It had not yet been discovered.

[Problem to be solved by the invention]

Therefore, an object of the present invention is to solve the above-mentioned problem that the discharge voltage decreases as the discharge frequency increases, and to provide a discharge tube that has stable discharge voltage characteristics regardless of changes in the discharge frequency. This is what I did.

[Means to solve the problem]

The discharge tube of the present invention that can achieve the above object has the following features:
A discharge tube having a pair of opposing electrodes and capable of starting a discharge by applying a pulse voltage, characterized in that an electrode made of a laminated metal body including at least a thin surface layer and a base layer is used as at least the cathode. That is.

Such an electrode may have a two-layer structure, a three-layer structure, or a multi-layer structure. The thin surface layer can be formed on the base layer by plating or the like, and its thickness is preferably within the range of 5 to -20 μm.

An electrode having such a structure is used at least as a cathode, but may be used as both a cathode and an anode. The shape of the electrodes can be appropriately determined depending on the use of the discharge tube so as to provide optimum characteristics, and is not particularly limited.

[For production]

In the discharge tube of the present invention equipped with the electrodes having the structure described above, the discharge voltage does not decrease much even if the discharge frequency increases.

A copper plate with a thickness of 0.5 mm and a large number of holes of about 0.5 mm at a pitch of about 1 crane was prepared. This perforated copper plate is press-formed so that the edges are rounded, and the inner and outer surfaces are coated with a thickness of approximately 10 mm.
Nisokel electroplating was performed to obtain a thickness of μm. As shown in FIG.
A cathode electrode was formed by applying a metal ring 3 to the electrode.

In addition, in the same manner, an electrode body 4 having a planar surface was obtained,
It penetrated the gas conduit 5 and adhered to an electrode stand 6 provided, and was caulked with a metal ring 7 to form an anode electrode.

On the other hand, the cathode electrode and the anode electrode were attached to both ends of a cylindrical casing 8 made of alumina ceramics so as to face each other, and the cylindrical casing 8 was sealed with a pin solder. Next, an inert gas was introduced and replaced into the internal space using a gas soda pipe 5, and the end of the conduit was crimped and sealed to obtain a discharge tube I of the present invention.

Formation 1 Instead of forming electrode bodies 1 and 4 from perforated copper plates, they were formed by press-forming similar perforated stainless steel plates, and then electroplating gold on the inner and outer surfaces to a thickness of about 10 μm. Then, in the same manner as in Example 1, the discharge tube (2) of the present invention was assembled.

Sexual trial test. FIG. 3 shows the configuration of an ignition device with a series cap for testing the performance of discharge tubes. T is the ignition coil, G,
(!: G. is the discharge gap of the discharge tube and spark plug, respectively, and C is the stray capacitance related to the high voltage cable, distributor cap, etc.

Using this device, we investigated the discharge voltage characteristics of discharge tubes i and n of the present invention and discharge tube ■ assembled using electrodes of exactly the same shape made of stainless steel, and the results shown in Figure 4 were obtained. was gotten.

〔Effect of the invention〕

The discharge tube of the present invention is constructed by providing a thin metal layer on the surface of the electrode, and the discharge voltage changes due to the ignition frequency are significantly improved, and the rotation speed of the engine of an automobile etc. This is because it has the advantage of being highly effective in maintaining stable operating conditions even when

[Brief Description of the Drawings] Figure 1 is a partially cutaway sectional view showing the structure of the discharge tube of the present invention, Figure 2 is a sectional view of an example of a conventional discharge tube, and Figure 3 is a series of discharge tube tests. Fig. 4 is a diagram showing the configuration of the ignition system with a gassop, and a graph showing the results of the discharge voltage test of the discharge tube. 1... Electrode body for cathode, 2... Electrode stand for cathode, 4...
- Electrode body for anode, 5... Gas conduit, 6... Electrode stand for anode, 8... Casing, a... Glass tube, b...
・Electrode, T...Ignition coil, G1...Discharge gear of discharge tube. 7b, G2...Spark plug discharge knob, C
...Floating capacitance.

Claims (2)

[Claims] (1) In a discharge tube equipped with a pair of opposing electrodes and capable of starting a discharge by applying a pulse voltage, an electrode made of a laminated metal body including at least a thin surface layer and a base layer is used as at least the cathode. A discharge tube characterized by: (2) The discharge tube according to claim (1), wherein the thickness of the surface thin layer in the electrode is within the range of 5 to 20 μm.