JPH0443957Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cathode assembly for an electron tube, and particularly to a mounting structure for a cathode mounting tube in the cathode assembly.

[Prior Art] Conventionally, the cathode structure of an electron tube is made of a ceramic material fitted into a support 1, as shown in FIG.
A disk 2, a cathode mounting tube 3 pushed into the through hole and locked, a cylindrical cathode sleeve 4 held by its sandwiching portion 3a, and a substantially disk-shaped cathode sleeve 4 inserted into one end of the disk 2; , a heater 6 disposed within the cathode sleeve 4 , and a cathode tab 7 connected to the cathode attachment tube 3 .

The mounting structure of the cathode mounting tube 3 is made of ceramic
The fitting portion with the disk 2 is welded, and the cathode tab 7 is connected to one place of the cathode attachment pipe 3 by welding.

[Problems to be solved] However, according to the above conventional cathode structure,
There are the following problems.

That is, when the heater 6 is heated, the cathode mounting tube 3 is also heated mainly due to heat conduction from the sandwiching part 3a, but heat is radiated through the cathode tab 7 connected near the sandwiching part 3a. At the same time, heat is radiated through the through-hole inner peripheral surface of the ceramic disk 2 which is in surface contact with the cathode mounting tube 3. Although the heater 6 effectively heats the cathode 5, due to the dissipation of such heat, it is necessary to supply a large amount of power to the heater 6 in order to bring the cathode 5 to a specified temperature. If the electric power is increased, the burden on the heater 6 will increase, resulting in faster deterioration of the heater 6.

An object of the present invention is to solve the above-mentioned problems, and to provide a cathode assembly that can suppress the dissipation of heat conducted from the heater to the cathode mounting tube and efficiently heat the cathode with low electric power.

[Means for Solving the Problems] In order to solve the above problems, the configuration of the cathode structure according to the present invention consists of the following four constituent elements.

The cathode mounting tube shall have an outward flange.

The ceramic disk must have a through hole that is larger than the diameter of the cathode mounting tube, and a metallized layer must be formed on at least the inner peripheral surface of the through hole.

The cathode tab must be brazed near one edge of the inner peripheral surface of the through hole.

A gap is provided between the cathode mounting tube and the inner peripheral surface of the through hole of the ceramic disk, and the outward flange is brought into contact with the vicinity of the other edge of the inner peripheral surface of the through hole. be attached.

[Function] According to the cathode structure having such a configuration, the cathode mounting tube is connected to the ceramic disk only by the brazed abutment, so the connection area is reduced, and the connection area from the cathode mounting tube to the ceramic disk is reduced. less heat escapes. In addition, the cathode tab is not directly fixed to the cathode mounting tube, but is connected near one edge of the inner peripheral surface of the through hole, so although it is electrically connected to the cathode mounting tube, Since the cathode tab is connected at a relatively distance from the abutting portion, only a small amount of heat escapes from the cathode tab.

[Example] Next, an example of the present invention will be described based on the drawings.

FIG. 1 is an enlarged longitudinal sectional view showing a first embodiment of the cathode assembly according to the present invention.

FIG. 2 is an enlarged plan view showing the same embodiment.

Reference numeral 10 denotes a cathode mounting pipe, and the lower end has a sandwiching part 10 for holding a cathode sleeve (not shown).
a, and a radiating wall 10c having the same diameter as the pipe portion 10b on the upper side. Pipe portion 10b and radiant wall 10c
are separated by an outward flange 11, which is configured as a circular flange as shown in FIG.

Reference numeral 12 designates a ceramic disk that is fitted into the support 1 and has a through hole 12a formed in its center. The diameter of this through hole 12a is the diameter of the tube portion 10b.
It is larger than the diameter of the outer flange 11, and smaller than the diameter of the outward flange 11. A metallized layer 12b is formed on the inner circumferential surface of the through hole 12a and in the vicinity of its upper edge.

Reference numeral 13 denotes a plate-shaped cathode tab, the upper end of which is fixed by brazing (not shown) near the lower edge of the inner peripheral surface of the through hole 12a.

The cathode mounting tube 10 has its tube portion 10b inserted into the through hole 12a of the ceramic disk 12, with a gap S provided between the inner peripheral surface thereof and the outward flange 11.
By applying brazing (not shown) to the abutting portion with the peripheral edge of the ceramic disk 1 abutting the vicinity of the upper edge of the inner circumferential surface of the through hole 12a,
It is attached to 2.

According to the first embodiment, the cathode mounting pipe 1
From the heater (not shown) in 0 to the cathode mounting pipe 1
Heat is conducted to 0, but ceramic disk 12
Since the contact portion with the outer flange 11 is only the peripheral edge of the outward flange 11, there is little heat dissipation. Further, since the cathode tab 13 is not directly fixed to the cathode mounting tube 10 but to the terminal end of the metallized layer 12b, heat escape through the cathode tab 13 is minimal.

FIG. 3 is an enlarged plan view showing another outward flange of the cathode mounting tube. This outward flange has projecting pieces 11a, 11b extending in three radial directions.
11c. Overhang pieces 11a, 11b, 11
The abutment part between c and ceramic disk 12 is
Since the amount of heat is reduced compared to the case of the circular outward flange 11 of the first embodiment, the dissipation of heat can be further suppressed.

FIG. 4 is an enlarged longitudinal sectional view showing a second embodiment of the cathode assembly according to the present invention. The difference from the first embodiment is that the radiation wall 10c is removed. According to this configuration, since the outward flange 14 does not require folding, the cathode mounting tube 10 can be easily manufactured.

FIG. 5 is an enlarged longitudinal sectional view showing a third embodiment of the cathode assembly according to the present invention. The difference from the first embodiment is that the diameter of the outward flange 15 is approximately the same as that of the through hole 12.
The metallized layer 16b is formed only on the inner peripheral surface of the through hole 12a, and after the outward flange 15 is press-fitted into the vicinity of the upper edge of the through hole 12a, the abutting portion is brazed (see Fig. (not shown).

According to this third embodiment, the outward flange 15
The abutment part between and the ceramic disk 12 is the first
Since the area is smaller than that in the embodiment, heat dissipation can be further prevented.

FIG. 6 is an enlarged longitudinal sectional view showing a fourth embodiment of the cathode assembly according to the present invention. The difference from the third embodiment is that the radiation wall 10c is removed. According to this configuration, since the outward flange 17 does not require folding, the cathode mounting tube 10 can be easily manufactured.

Note that the shape of the outward flange may be circular, as described above, or may be formed of overhanging pieces extending in three radial directions, or may be formed of overhanging pieces extending in two radial directions or in four radial directions.

[Effects of the invention] As explained above, according to the cathode assembly according to the invention, the cathode mounting tube is provided with an outward flange, a metallized layer is formed on at least the inner peripheral surface of the through hole of the ceramic disk, and the A cathode tab is brazed near one edge of the inner peripheral surface of the hole, and a gap is created between the cathode mounting tube and the inner peripheral surface of the through-hole of the ceramic disk, so that the peripheral edge of the outward flange is inserted into the through-hole. Since it is characterized in that the abutting portion is brazed while abutting against the vicinity of the other edge of the circumferential surface, the following effects are achieved.

In other words, the heat from the cathode mounting tube is
Since the heat is dissipated only through the vicinity of the other edge of the disk, less heat is radiated than in the past, and the heater can heat the cathode more efficiently. Accordingly, less power can be supplied to the heater.

In addition, when the outward flange is constructed from overhanging pieces extending in three radial directions, the contact area with the ceramic disk becomes even smaller, so that heat radiation can be further suppressed.

[Brief explanation of the drawing]

FIG. 1 is an enlarged longitudinal sectional view showing a first embodiment of the cathode assembly according to the present invention. FIG. 2 is an enlarged plan view showing the same embodiment. FIG. 3 is an enlarged plan view showing another outward flange of the cathode mounting tube. FIG. 4 is an enlarged longitudinal sectional view showing a second embodiment of the cathode assembly according to the present invention. FIG. 5 is an enlarged longitudinal sectional view showing a third embodiment of the cathode assembly according to the present invention. FIG. 6 shows the fourth cathode assembly according to the present invention.
FIG. 3 is an enlarged vertical cross-sectional view showing an example. FIG. 7 is an enlarged sectional view showing an example of a conventional cathode assembly. DESCRIPTION OF SYMBOLS 1... Support body, 2, 12... Ceramic disk, 3, 10... Cathode mounting tube, 3a, 10
a...Pinching part, 4...Cathode sleeve, 5
... Cathode, 6 ... Heater, 7, 13 ... Cathode tab, 10b ... Pipe section, 10c ... Radiation wall,
11, 14, 15, 17... outward flange, 1
1a, 11b, 11c... overhang piece, 12a... through hole, 12b, 16b... metallized layer, S... void.

Claims (1)

[Scope of claims for utility model registration] (1) A cathode mounting pipe having an outward flange;
A ceramic disk having a through hole larger than the diameter of the cathode mounting tube and having a metallized layer formed on at least the inner peripheral surface of the through hole, and a ceramic disk near one edge of the inner peripheral surface of the through hole. a brazed cathode tab, a gap is provided between the cathode mounting tube and the inner peripheral surface of the through hole of the ceramic disk, and the peripheral edge of the outward flange is connected to the other inner peripheral surface of the through hole. A cathode structure characterized in that the abutting portion is brazed with the abutting portion near the edge. (2) The cathode assembly according to claim (1) of the utility model registration claim, wherein the outward flange is comprised of projecting pieces projecting in three radial directions.