JPH02247941A - Manufacture of cathode for electron tube - Google Patents

Abstract

PURPOSE:To make a welding area of two upper and lower electrodes in a specific constant size by welding a heater lead and a heater support while nipping them between the electrodes facing each other with a specific gap maintain by means of interposition of an insulating spacer. CONSTITUTION:An insulating spacer 13 of a specific size is interposed between upper and lower electrodes 10 and 11 to form a specific minimum gap between both electrodes. A heater lead 5a and a heater support 6 are overlapped on each other, nipped and resistance welded between both electrodes. The heater lead 5a is pressed and deformed in its cross section to have a specific gap 1 between both electrodes and brought in contact with the heater support 6 with a specific contact area. The heater lead 5a and the heater support 6 are welded to each other with a specific contact area so that formation of a cathode of stable characteristic is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a cathode for an electron tube, and particularly to a method for welding a heater and a heater support.

[Conventional technology]

As a cathode structure for an electron tube, an indirectly heated, shaped pole structure as shown in FIG. 3 is widely used. This cathode structure has a base body 2 with a thermionic emissive substance l provided on the top, a cylindrical sleeve 3 that fits into the base body 2, a disk 4 that fits and holds the sleeve 3, and has a bottom part of the sleeve 3 and a small part. A gap A is provided and the cathode heater 5 is inserted into the sleeve 3.

In the cathode assembly having such a configuration, the lead portion of the heater 5, that is, the heater lead 5a, is welded and joined to the heater support 6 so that the gap A between the heater 5 and the bottom of the sleeve 3 is constant.

In this case, the size of the welded portion between the heater lead 5a and the heater support 6 is important.

If the contact area of 6 is large, the welded part will also be large.
If the contact area of 6 is small, the welded portion will also be small.

If the welded part between the heater lead 5a and the heater support 6 is too large, the heater coil 5b and the heater support 6
The performance of the heater 5 (the ability to heat the thermionic emitting material 18) increases.

(the same applies hereafter), and if the welded part between the heater lead 5a and the heater support 6 is too small, the heater coil 5b
The necessary current supply to the heater 5 is restricted, and the performance of the heater 5 is degraded. Therefore, even in the case of E rising and falling, the performance of the heater 5 is reduced and the electron emission characteristics of the cathode are deteriorated. , 6 welding must be performed.

In FIG. 4, both sides of a heater support 6 and a lower electrode 7 on which it is placed are formed into curved surfaces, and heater leads 5a are arranged on the curved surfaces of the heater support 6.

A method of joining the heater lead 5a and the heater support 6 by resistance welding by pressing the upper electrode 8 from the upper blade to a certain deformation of the heater lead 5a is shown (Utility Model No. 51-5
6951).

In the method shown in Fig. 1g4 above, since the deformation of the heater lead 5a is limited by the depth H of the curved surface of the heater support 6, the heater lead 5a is determined by the deformation of the heater lead 5a.
The contact area between the heater support 6 and the heater support 6 is maintained at a predetermined size, thereby forming a desired welded portion.

[Problem to be solved by the invention]

According to the above conventional method of forming the heater support 6 into a curved surface and joining the heater lead 5a and the heater support 6 by resistance welding, the heater lead 5a and the heater support 6
Which contact area is determined by the outer diameter of the heater lead 5a before deformation, and the curvature and depth H of the heater support 6.

curvature and depth H of the heater support 6
In order to mold with high precision, sophisticated processing means are required, which inevitably increases costs.

Further, when the upper electrode 8 is suppressed by the upper blade, the curved surface of the heater support 6 is expanded, and both the curvature and the depth gH of the curved surface change, so that the contact state between the heater lead 5a and the heater support 6 changes. Therefore, the welded portions of both 5a and 6 cannot be controlled to the same size, which causes deterioration of the heater characteristics as described above.

An object of the present invention is to perform welding while controlling the contact area between the heater lead and the heater support to a constant value, and form the welded part between the heater lead and the heater support to a desired size, in view of the problem described in 1. The purpose is to provide a welding method that allows

[Means to solve the problem]

The above purpose is to provide a method for manufacturing an electron tube cathode in which a heater lead and a heater support are stacked and sandwiched between upper and lower electrodes provided facing each other, and the two are joined by resistance welding. The above-mentioned insulating spacer controls the deformation of the heater lead to a predetermined size.
This is achieved by welding between the lower electrodes.

[Effect]

With the above means, the deformation of the heater lead is limited to a certain level, so that the contact area between the heater lead and the heater support is maintained constant. If you perform resistance welding under these conditions, the weld area between the heater lead and the heater support will have a large I.
K-za is formed uniformly.

Deterioration of heater performance due to unstable bonding of the welded portion can be prevented.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Note that the same members as in FIG. 3 are designated by the same reference numerals.

In FIG. 1, 10 is a lower electrode, and 10a is a lower electrode 10 for vacuum adsorbing the heater support 6 to the lower electrode 10.
0 is a suction hole, 11 is a set of upper electrodes which are opposed to the lower electrode 10 and are movable up and down by a device not shown, and 11a is a 1st electrode to prevent the heater lead 5a from shifting. This is a holding groove provided in 11. Also, 12
is a power source for resistance welding the heater lead 5a and the heater support 6 by passing a current through the picture electrodes 10 and 11.

In the present invention, an insulating spacer 13 is provided between the hill and the lower electrodes 10 and 11 via the heater support 6 to control the heater lead 5a, which is deformed by being pressed by the upper electrode 11, to a predetermined dimension l. .

In such a configuration, when the heater lead 5a is placed on the heater support 6 placed on the lower electrode 10 and then the upper electrode 11 is moved downward, the heater lead 5a is in the state shown by the chain line before deformation. It is pressed and deformed. Here 1
Since the insulating spacer 13 is interposed between the lower electrodes 10.11, the movement of the upper electrode 11 is thereby restricted.
The deformation of the heater lead 5a is controlled to a predetermined dimension l.

Therefore, the contact area between the heater lead 5a and the heater support 6 is maintained at a predetermined size according to the deformation of the heater lead 5a shown in E, and by performing resistance welding in this state, the contact area between the heater lead 5a and the heater support 6 can be stably formed to a desired size.

FIG. 2 shows an embodiment in which a current is input to the lower electrode 14. A heater lead 5a and a heater support 6 are stacked and sandwiched between the first side electrode 15 and the lower electrode 14, which are provided so as to be movable up and down, and a current is applied to the heater lead 5a.
This is a method of resistance welding the heater support 6 and the heater support 6.

In this case as well, there is no insulating space between the upper and lower electrodes 14 and 15.
16, and the heater lead 5a is connected to the upper electrode 15 through the
to press. In this way.

By deforming the heater lead 5a to a predetermined size l, the welded portion between the heater lead 5a and the heater support 6 can be formed to a desired size.

〔Effect of the invention〕

According to the present invention described above, since the welded portion between the heater lead and the heater support is formed to a desired size, the problem of deterioration of heater characteristics due to the state of formation of this welded portion is solved, and stable characteristics can be achieved. A cathode of

Furthermore, since the method of the present invention only performs welding with an insulating spacer interposed between the electrodes, it can be carried out at low cost, and has the effect of ensuring high precision even with a welding force of 1.

[Brief explanation of drawings]

Fig. 1 is a side view of the essential parts of one embodiment of a welding device for explaining the method of the present invention, Fig. 2 is a side view of the main parts of another embodiment similar to Fig. 1, and Fig. 3 is an indirectly heated type welding device. Cross-sectional view of main parts of cathode structure, No. 4
The figure is a side view of a main part of a welding device for explaining a conventional welding method. 5... Heater, 5a... Heater lead, 5
b... Heater coil, 6... Heater support. 1O...lower electrode, 11...upper electrode. 11a... Holding groove, 12... Power supply. Green spacer, 14...lower electrode. Side electrode, 16...insulating spacer. 13... Absolute 15... Top Figure 1 ■ 50: Heater lead 6; : Inconvenience 341 bird b 15: Upper #J Denei 16: Itoiro Silkworm 1 Su〆-sa

Claims (1)

[Claims] 1. In a method for manufacturing an electron tube cathode, in which a heater lead and a heater support are stacked and sandwiched between upper and lower electrodes that are provided facing each other, and the two are joined by resistance welding, the heater is pressed by the upper electrode. A method for manufacturing a cathode for an electron tube, characterized in that welding is performed by interposing an insulating spacer between the upper and lower electrodes to control deformation of the lead to a predetermined size.