JPH057811B2 - - Google Patents

Description

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

The conventional electron tube cathode structure is as shown in Figure 1.
A filament 1 that emits thermoelectrons, an upper end shield 2 and a lower end shield 3 arranged to sandwich the upper and lower ends of the filament 1, and a center lead 4 and side leads that hold the upper and lower end shields 2 and 3, respectively. A lead 5 and an insulator 6 through which these leads 4 and 5 are fixed.
, a seal component 7 fixed to the upper end of the insulator 6, and a terminal 8 fixed to the lower end of the insulator 6 and connected to the leads 4 and 5, respectively.

The manufacturing method is as shown in Figure 2.
First, the side leads 5 and the center lead 4 are fixed to the lower end shield 3 by butt welding, etc.
, the insulator 6, the seal part 7, and the terminal 8 are assembled using a jig, and a brazing material is supplied between the fixed parts, and the brazing material is fused to complete the stem assembly 9. Assemble the filament 1 into the stem assembly 9, insert the upper end shield 2 into the through hole 2a of the upper end shield 2, and then apply Ru/Mo powder or platinum to the three points A, B, and C shown in Fig. 3. The cathode structure shown in FIG. 1 was completed by supplying high melting point metal brazing filler metals and fusing them together.

However, in the cathode assembly having such a structure, the center lead 4 is inserted into the through hole 2a of the upper end shield 2 as described above, and both 2 and 4 are fixed with a brazing material. Since there is a fitting margin, the upper end shield 2 may be tilted depending on the size combination with the filament 1. When this inclination occurs, the ability to prevent thermoelectrons from escaping, which is one of the functions of the end shield, is reduced. Further, since the lower end shield 3 and the side leads 5 can be fixed in advance by butt welding, no metal brazing material is required, but the upper end shield 2 and the center lead 4 cannot be assembled using a metal brazing material in the conventional assembly method described above. This has disadvantages such as requiring an additional amount of expensive metal brazing material.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a method for manufacturing an electron tube cathode structure, which can assemble an upper end shield with high precision without tilting, and can reduce cost. shall be.

Hereinafter, the present invention will be explained with reference to illustrated embodiments.
Note that the same members as in FIG. 1 will be described with the same reference numerals. FIG. 4 is a partial cross-sectional view showing an example of the upper end shield and center lead used in the cathode structure according to the present invention, and FIG. 5 is a cross-sectional view showing an example of the method for manufacturing the cathode structure according to the present invention. It is a diagram.
As shown in FIG. 4, the upper end shield 12 does not have a through hole for inserting the center lead 14, and the surface on the center lead 14 side is flat. As shown in FIG. 5, the stem assembly jig is used to position the upper and lower end shields 12 and 3 in the radial direction.
End shield fitting hole 2 into which the outer circumferences of 2 and 3 fit
End shield positioning body 20 in which 0a is formed
, a vertical positioning body 21 that fits into the end shield fitting hole 20a of the end shield positioning body 20 to position the top and bottom end shields 12, 3, and the end shield positioning body 2.
0 and a terminal positioning body 23 that fits into the insulator 6 and positions the terminal 8.

Next, a method for manufacturing a cathode assembly according to the present invention will be explained. First, as shown in FIG. 4, the upper end shield 12 and the center lead 14 are butted together and welded together using a welding method such as electric resistance welding or friction welding. Further, the lower end shield 3 and the side leads 5 are fixed by welding as in the conventional case.

Next, as shown in FIG. 5, the upper end shield 12 to which the center lead 14 is fixed and the vertical positioning body 21 are sequentially inserted into the end shield fitting hole 20a of the end shield positioning body 20, and then inside the vertical positioning body 21. After that, the lower end shield 3 to which the side leads 5 are fixed is inserted into the end shield fitting hole 20a.
Next, the seal component positioning body 22 is combined with the end shield positioning body 20, the seal component 7 is fitted into the seal component positioning body 22, and the insulator 6 is placed thereon. And center lead 1
4. Insert the terminals 8 into each side lead 5,
After that, insert the terminal positioning body 23 into the insulator 6,
Press the terminal 8 against the insulator 6. This allows each component to be positioned. Also, during the assembly, between the seal component 7 and the insulator 6, between the insulator 6 and the terminal 8, between the terminal 8 and the center lead 14, and between the side lead
In between, silver and copper solder etc. are supplied respectively, and in this state they are put into a furnace and the stems are assembled 14, 5, 6, 7,
Complete brazing in step 8. After that, the cathode assembly with the stem assembled is taken out from the jig, and high melting point brazing filler metal such as Ru/Mo or platinum is supplied to the two points A and B as shown in Fig. 6, and the filament 1 is placed in a furnace. are fused to the upper and lower end shields 12 and 3, thereby completing the cathode assembly.

In this way, since the upper end shield 12 and the center lead 14 are fixed by welding in advance, the upper end shield 12 can be fixed in the correct position with respect to the center lead 14 using a simple jig (not shown) without tilting. can do. Furthermore, if a large inclination occurs, it can be rejected before assembling the stem, resulting in excellent productivity. Furthermore, since there is no need to supply expensive metal brazing material to the upper end shield 12 and center lead 14, costs can be reduced accordingly. Furthermore, since there is no need to provide a through hole in the upper end shield 12, when molding the upper end shield 12 by powder firing, the mold can be simplified. Further, as shown in FIG. 2, when the through hole 2a is formed in the upper end shield 2, if the thickness of the cylindrical portion 2b of the upper end shield 2 is small, the powder will not be filled smoothly into the cylindrical portion 2b. However, such a shape can be easily molded by not providing a through hole as in the present invention. Furthermore, even when the upper end shield 12 is manufactured by cutting or sheet metal processing, since no through holes are required, the number of man-hours required for the processing is also unnecessary, and from this point of view as well, costs can be reduced.

Conventionally, the center lead and side leads were fixed to the cathode stem insulator using a brazing material, and then the filament, upper end shield, etc. were fixed to these using a high-melting point metal brazing material.
Because one end of the center lead is already fixed to the cathode stem insulator, the positioning jig for the center lead and the upper end shield becomes complicated, making it difficult to obtain orthogonality between the center lead and the upper end shield with high precision. Ta. Furthermore, fixing the center lead to the upper end shield required expensive metal brazing material, making it expensive.

However, in the present invention, since the upper end shield and the center lead are fixed in advance, this fixing can be done with high precision using a simple jig, and a fitting hole is provided in the end shield positioning body, so that the upper end shield and the center lead can be fixed in advance. By simply inserting the end shield, upper and lower end shield positioning bodies, filament, and lower end shield into this fitting hole in sequence, their accurate positioning will be performed automatically, and then by fitting to this end shield positioning body, etc. Since the seal part positioning body can be assembled accurately, a high-precision cathode structure can be produced by incorporating other parts that make up the cathode stem into this seal part positioning body and fixing the cathode stem parts with brazing material. You can get it easily. Furthermore, there is no need to use an expensive metal brazing material to secure the center lead and the upper end shield, so costs can be reduced.

As is clear from the above description, according to the method for manufacturing a cathode assembly according to the present invention, accuracy can be improved and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional cathode structure, FIGS. 2 and 3 show the assembly process of a conventional cathode structure, FIG. 2 is a sectional view of the stem assembly, and FIG. 3 is an assembly sectional view of the filament part. FIG. 4 is a partial cross-sectional view showing an example of the upper end shield and center lead used in the cathode structure according to the present invention, and FIG. 5 is a cross-sectional view showing an example of the method for manufacturing the cathode structure according to the present invention. FIG. 6 is an assembled sectional view of the filament portion. 1...Filament, 3...Lower end shield, 5...Side lead, 6...Insulator, 7...
Seal parts, 8...Terminal, 12...Top end shield, 14, 14A, 14B...Center lead, 20...End shield positioning body, 21...
...Vertical positioning body, 22... Seal component positioning body, 23... Terminal positioning body.

Claims (1)

[Claims] 1. An electron tube cathode assembly having a filament that emits thermoelectrons, an upper end shield and a lower end shield arranged to sandwich the upper and lower ends of the filament, and a center lead and side leads that respectively hold these upper and lower end shields. In the manufacturing method, the lower end face of the upper end shield and the upper end face of the center lead, and the lower end face of the lower end shield and the upper end face of the side leads are welded and fixed in advance, respectively, and the upper end shield and the upper and lower end shields are positioned. The body is sequentially inserted into the fitting hole provided in the end shield positioning body, then the filament is inserted into the upper and lower end shield positioning body, then the lower end shield is inserted into the fitting hole, and then the A seal component positioning body is combined with the end shield positioning body, other parts constituting the cathode stem are assembled into the seal component positioning body, the cathode stem component is fixed with a brazing material, and then the filament and the upper and lower end shields are connected. A method for manufacturing an electron tube cathode structure, characterized in that it is fixed with a high melting point brazing material.