JPS63138625A - Electron tube - Google Patents

Abstract

PURPOSE:To prevent a pipe electrode support bar from bending or the like with a simple structure as well as to aim at improvement in mechanical strength, by having this pipe electrode support bar tightly attached to an external terminal through a tubular extension part, and fitting a holding ring closely between a pipe tip of this tubular extension part and the electrode support bar inserted through the inside. CONSTITUTION:An electrode support bar 21 is inserted through a tubular extension part 27 of an external terminal 25. A lower end of this electrode support bar 21 is closely inserted into a lower through hole 25b of the electrode terminal 25, and under this state, a holding ring 28 is pressed in a tapered inner surface 27a of a tip at the pipe inside of this tubular extension part 27. This holding ring 28 is pressed in space between the support bar 21 and the tubular extension part 27 by a slit 28b and a taper outer circumferential surface 28c, and closely fitted therein. With this constitution, such a fear that the electrode support bar 21 will cause any eccentricity inside the pipe is nothing at all and, what is more, this electrode support bar 21 can be constituted of a single member, thus such an electron tube that is excellent in mechanical strength and good in a characteristic, beside high accuracy is securable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an electron tube, and particularly to an electrode support structure thereof.

(Prior Art) In various electron tubes such as transmitting tubes, magnetrons, traveling wave tubes, and talistrons, support structures for electrodes in the tubes are increasingly requiring higher precision in recent years. For example, the filament support structure of the transmitting tube has a structure as shown in FIG. In the figure, reference numeral 11 is a coiled filament cathode, 12 and 13 are electrode support rods whose tips are welded and fixed, and 14 is a sealing ring that forms part of the vacuum container.
15 and 16 are ceramic insulating cylinders, and 17 and 18 are external terminals. Electrode support rod 12 extended into the tube
．． 13 is made of a metal with a high melting point such as molybdenum, and is connected to external terminals 17 and 18 made of iron alloy by arc welding or the like. This welded part is marked with the symbol @B.

(Problem to be solved by the invention) However, the welding part B between the electrode support rod and the external terminal is
As shown in the above, only a portion of the butt portion between the two is likely to be melted and joined, so stress strain is likely to remain. As a result, as shown in FIG. 6, the center C of the electrode support rod tends to be eccentric with respect to the tube axis 0, creating an angle θ. If the tube electrode support rod is bent in this way, the tube electrode will naturally become eccentric.
This has the disadvantage that predetermined characteristics cannot be obtained. Also,
The welded part is likely to be incomplete, and there is a risk that sufficient mechanical strength may not be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electron tube which eliminates the above-mentioned disadvantages, has a relatively simple structure, prevents bending of the electrode support rod in the tube, and has an electrode support structure with excellent mechanical strength. .

[Structure of the Invention] (Means for Solving the Problems) In this invention, the electrode external terminal is integrally provided with a cylindrical extension projecting inside the insulating cylinder, and the cylindrical extension is inserted into the pipe through the cylindrical extension. This is an electron tube in which an electrode support rod is fixed to an external terminal, and a retaining ring is tightly fitted between the inner end of the cylindrical extension and the electrode support rod inserted inside the tube. Note that it is desirable that a slit be formed in a part of the retaining ring so that the retaining ring can be tightly fitted between the two.

(Function) According to the present invention, the electrode support rod is inserted into the electrode external terminal having the cylindrical extension protruding inside the insulating cylinder, and is bonded and fixed at the end thereof, and Since the retaining ring is tightly fitted between the inner end of the tube of the extension and the electrode support rod, the electrode support rod is mechanically held in two places, reducing the risk of eccentricity of the inner tube part. . Moreover, this electrode support rod can be constructed from a single member, which provides excellent mechanical strength.

In this way, an electron tube with high precision and good characteristics can be obtained.

(Example) An example will be described below with reference to the drawings. Identical parts are designated by the same reference numerals.

FIGS. 1 and 2 show the main parts in a completed state. The electrode support rods 21 and 22 are single rods made of molybdenum, and are bent into crank shapes at predetermined locations 23 and 24. On the other hand, seven large-diameter flange portions 25a and 26a of external terminals 25 and 26 made of iron alloy are joined to the ceramic insulating tube 15 and 16 by hermetic soldering portions C, respectively. This external terminal 25 (only one is shown) has insulation I! ! 112
A cylindrical extension portion 27 protruding inwardly from the housing 5 is integrally provided in advance. The inner surface of the inner end of the cylindrical extension 27 is a tapered surface 27a.

Further, a retaining ring 28 shown in FIG. 2 is prepared. This retaining ring 28 is made of an iron alloy that is easily welded to the cylindrical extension 21, and its central through hole 28a has a diameter slightly larger than the diameter of the electrode support rod 21, and a slit 28b is formed in a part. Further, the outer peripheral surface is a tapered surface 28c.

Now, to explain the preferred assembly procedure, first, as shown in the third factor, the retaining ring 28 is fitted onto the electrode support rod 21. Then, this electrode support rod 21 is connected to the external terminal 2.
5 through the cylindrical extension 27.

The lower end of this electrode support rod 21 is tightly inserted into the lower through hole 25tl of the electrode terminal 25. In this state, as shown in FIG. 1, the retaining ring 28 is tightly press-fitted into the tapered inner surface 27a of the inner end of the cylindrical extension 27. Retaining ring 28
is due to the slit 28b and the Taber outer peripheral surface 28c,
It is press-fitted between the support rod and the cylindrical extension and is a tight fit. Note that the retaining ring 28 is spot welded to the end of the cylindrical extension 27 at point A to prevent it from coming off. In this state, the lower end is airtightly joined and fixed by arc welding or brazing. This airtight joint is marked with the symbol B.

In this way, the electrode support rod is mechanically and stably fixed to the external terminal at two locations: the joint B at the lower end and the retaining ring 28.

[Effects of the Invention] As explained above, according to the present invention, there is no risk of the electrode support rod being eccentric in the tube, and it is also possible to configure the electrode support rod with a single member, which improves mechanical strength. It is possible to obtain an electron tube with high precision and good characteristics.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of main part II showing an embodiment of the present invention;
The figure is a perspective view of the main part, Fig. 3 is an exploded view showing the assembled state, Fig. 4 is a vertical sectional view of the main part showing the conventional structure, Fig. 5 is a sectional view of the main part, and Fig. 6 is a side view of the main part. It is a diagram. 21.22... Electrode support rod, 15... Insulating tube, 25
... External terminal, 27... Cylindrical extension part, 28... Retaining ring, 28b... Slit, B... Joint part. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 3 Figure 6

Claims (2)

[Claims] (1) In an electron tube in which an electrode support rod extends into the tube by penetrating an insulating cylinder in which an electrode external terminal is hermetically sealed, a cylindrical extension part is integrally provided on the inside of the insulating cylinder at the external terminal, The electrode support rod is fixed to the external terminal through the cylindrical extension, and a retaining ring is tightly fitted between the inner tip of the cylindrical extension and the electrode support rod inserted inside the tube. An electron tube characterized by: (2) The electron tube according to claim 1, wherein the holding ring has a slit formed in a part thereof.