JPS584241A - Manufacture of indirectly heated cathode structure - Google Patents

Abstract

PURPOSE:To enable a welding with a high welding strength and a high reliability to be performed by welding an inner and an outer sleeve, which constitute an indirectly heated cathode structure, by use of laser light after the clearance formed between the inner and the outer sleeves is removed by making them in close contact with one another. CONSTITUTION:An inner sleeve 4 is subjected to oxidation treatment carried out at 900-1,100 deg.C in a furnace of wet hydrogen for 5-30 minutes so as to form an oxidized film 41 over the surface of the inner sleeve 4. On the other hand, after the circumference wall of a base metal 2 fitted into one end of an outer sleeve 3 is fixed to the sleeve 3 by a resistance welding, the inner sleeve 4 is inserted into the outer sleeve 3. Next, a core metal is inserted between the inner and the outer sleeves 4 and 3 so that the core metal touches the inner sleeve 4. Then, the outer sleeve 3 is deformed by applying external pressure so as to make the inner and the outer sleeves 4 and 3 to closely touch one another and to remove the clearance between the sleeves 4 and 3. After that, a laser light (L) is irradiated on a given part of the outer sleeve 4 from almost a perpendicular direction so as to make the inner and the outer sleeves 4 and 3 to be welded and fixed together and a welding point 3a.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an indirectly heated cathode assembly.

As shown in Fig. 1, the passion-shaped cathode structure used in shadow ray tubes, etc. consists of a base metal (2), which is made up of 2 kels and contains an electron-emitting substance (1) and contains a nine-reducing element. An actor sleeve (3) made of nickel or the like to which a base metal (2) is fixed; and an inner sleeve (4) made of a nickel-chromium alloy or the like having one end inscribed in the outer sleeve (3).

The inner sleeve (4) is composed of a cathode support cylinder (6) which is suspended and fixed to the other end of the inner sleeve (4) via three cathode supports (5).

Such a 11 kJit cathode assembly is a power-saving, fast-acting, indirectly heated cathode assembly in which a dark green oxide film is formed on the surface of the inner sleeve (4).

More specifically, by forming an oxide film on the surface of the inner sleeve (4), the thermal emissivity is increased.
Inner sleeve (4) K absorbs heat from the inserted heater (not shown), increases radiant energy during steady operation, and increases the power of input 7 when this energy is met. This improves interlocking. On the other hand, the actor sleeve (3) is a radiant heat insulating tube. Since the claw 9 has a metallic luster and a low thermal emissivity, the radiant energy during steady operation is reduced, and the input power of the heater corresponding to this energy is reduced, thereby saving power.

By combining the two contradictory effects of jin, it has both interlocking properties and power saving properties.

By the way, such an oxide film on the inner sleeve (4) can be easily formed by heating it in a wet hydrogen furnace.

However, the oxide film thus formed has extremely high resistance, and it is difficult to weld and secure the actor sleeve (3) by resistance welding after forming the K oxide film on the inner sleeve (4).

For this purpose, it is known to form an oxide film on the surface and use a laser beam to weld the inner sleeve (4) and the actor sleeve (3).

However, the actor sleeve (3) of the indirectly heated cathode assembly shown in FIG. 1 has an outer diameter of about 1.40 mm and a wall thickness of about 0 to 2 smt.

The inner sleeve (4) has an outer diameter of about 1.32 m11φ and a wall thickness of about 0.02 m, and is the same as the inner diameter of the actor sleeve (3). The clearance with the outer diameter of the sleeve (4) is Q on one side and 92 mtg degrees. This level of clearance is naturally a necessary value considering mass productivity.

However, when welding the inner sleeve (4) and the actor sleeve (3), which have such a clearance, by laser beam irradiation, as shown in Figure 111!2, the outer sleeve (3) When the outer sleeve (3) and the inner sleeve (4) are welded together by irradiating the laser beam (L), the wall thickness of the end of the laser irradiated part of the actor sleeve (3) becomes thinner and melts, causing the outer sleeve (3) to look like the outer sleeve (3).
The K hole (3,) is opened, resulting in the outer sleeve (3,
) and the inner sleeve (4) have a disadvantage in that the strength of the welding point (3a) is weakened. This also applies to the case of welding the inner sleeve (4) and the side wall portion of the cap in which the base metal and the actor sleeve are integrally formed.

The present invention was made in view of the above-mentioned conventional drawbacks, and it is possible to obtain a high-quality indirectly heated cathode structure by performing highly reliable welding (using laser light) without compromising mass productivity. It is an object of the present invention to provide a method for manufacturing a indirectly heated cathode structure.

Next, an embodiment of a method for manufacturing an indirectly heated cathode assembly according to the present invention will be described with reference to the drawings. In the figure, parts that are the same as those of the conventional one are given the same reference numerals and will not be described.

First, as shown in Fig. 3, the inner sleeve (4) is oxidized in a wet hydrogen oven at 900-1100°C for 5-30 minutes to form an ElliK oxide film layer (4□) on the surface of the inner sleeve (4). Form. On the other hand, as shown in Fig. 4, the base metal (2
) is inscribed and the outer periphery is attached by resistance welding.

Next, as shown in FIG. 5, the inner sleeve (4) is inserted into the outer sleeve (3)K. Next, as shown in Fig. 6, after inserting the core metal (7) that is inscribed in the inner sleeve (3) K, external pressure is applied to the vicinity of the actor sleeve (3), including a predetermined position, to remove the outer sleeve (3). Transform inner sleeve (4) and outer sleeve C3)tFE*
to eliminate clearance.

Next, as shown in FIG. 7, a laser beam (L) is irradiated onto a predetermined position of the outer sleeve (4) from a substantially perpendicular direction.
Actor sleeve (3) and inner sleeve (4) are S-bonded and fixed at welding point (3a).

By pressurizing the outer sleeve (3) in this way and eliminating the clearance with the inner sleeve (4), V-
The outer sleeve (3) does not become partially thin during 4-light irradiation, and there is no hole (3 m) created due to melting of the actor sleeve (3) as in the past, resulting in extremely high quality and reliability. Welding is now possible.

In addition, in order to obtain the same effect, as shown in No. 811, by pressurizing the 8 rod (8), the internal pressure of the inner sleeve (4) K can be applied by expanding the 8 rod (8) near the sand predetermined part. A similar effect can be obtained.

The outer sleeve (3) is used as a means to apply external pressure.
A method of applying mechanical pressure with a punch or an ultrasonic Sm
Possible methods include a method in which the vibrator of the machine is brought into contact with IIIk and oscillated once, and pressure is applied by frictional heat, but the method is not limited to this. Also, as a means of applying internal pressure, an elastic body such as rubber (
81) may be provided as a part of the 8 rod (8) by inserting it from the opening side of the inner sleeve and pressurizing it, but the method is not limited to this.

In addition, although we have described welding the outer sleeve and inner sleeve in this text, the same applies to welding the cap-shaped base metal (9) of II ml g (s,) as shown in Fig. 9. Needless to say.

As described above, according to the present invention, the inner sleeve and outer sleeve constituting the passion-shaped cathode structure are brought into pressure contact and welded by laser light after eliminating the clearance.
Since it is possible to perform highly reliable welding with strong II contact strength, its industrial value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of an indirectly heated electrode assembly. Figure 2 is an explanatory diagram showing the state of welding using conventional laser light;
Figures 3 to 117 are cross-sectional views showing the inner sleeve of the crane-shaped cathode structure of the present invention, Figure 4 is a cross-sectional view showing the outer sleeve fixed to the base metal, and Figure 5 is a cross-sectional view showing the inner sleeve inserted into the outer sleeve. A cross-sectional view showing the state, Figure 6 is a cross-sectional view of the main part showing the state where the core metal is inserted into the inner sleeve and external pressure is applied to the actor sleeve, and Figure 7 is a main part showing the state where the core metal is inserted into the inner sleeve and external pressure is applied to the actor sleeve. 8 is a cross-sectional view of a main part showing another embodiment of the method for manufacturing an indirectly heated electrode structure of the present invention, and FIG. 9 is a view of another indirectly heated electrode structure to which the manufacturing method 1 of the present invention is applied. FIG. 3 is a sectional view of a main part of the pole structure. 1... Electron emitting material 2.9... Base metal 3.
91...Outer sleeve 4--Inner sleeve 3a...Welded part 3m...Hole 7...
・Core metal 8...8 rods 9m...Side wall agent Patent attorney Inoue - 1st man! 1 Figure 7 Figure 8

Claims (1)

[Claims] An inner sleeve is inserted into a side wall of an outer sleeve or a cap-shaped base metal to which a flat base metal coated with an electron emitting substance is welded, and the outer sleeve or side wall and the inner sleeve are fixed by welding. In the method for manufacturing a indirectly heated cathode assembly, after inserting an inner sleeve into the outer sleeve or the side wall, an external pressure is applied to the outer sleeve or the side wall, and/or an internal pressure is applied to the inner sleeve. A method for producing an indirectly heated cathode assembly, comprising the steps of: bringing a predetermined portion of the inner sleeve into pressure contact with the outer sleeve or the side wall portion; and irradiating the predetermined portion with a laser beam and fixing the predetermined portion by welding. .