JPH0616380B2 - Magnetron cathode assembly - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a magnetron cathode assembly, and more particularly to a magnetron cathode assembly with improved vibration resistance of filament.

[Background of the Invention]

FIG. 1 is a cross-sectional configuration diagram of a main part showing an example of a cathode assembly of a magnetron. In the figure, a spiral filament 1 that emits thermoelectrons is arranged concentrically with the tube axis of a magnetron, and is supported and fixed to an upper end shield 2 and a lower end shield 3 that prevent deviation of thermoelectrons in the tube axis direction. ing. The upper end shield 2 is fixed to the upper end of the center lead 4 on the tube axis, and the lower end shield 3 is fixed to the upper end of the side lead 5 so that the center lead 4 passes through the center of the circular hole 3a. . In addition, the lower ends of the center lead 4 and the side leads 5 have power supply terminals 6
Is brazed together with the stem ceramic 7 and a seal component 8 is fixed to the stem ceramic 7 by silver brazing to form a magnetron cathode assembly.

However, in the magnetron cathode assembly having the above structure, the tip ends of the center lead 4 and the side leads 5 whose lower ends are supported and fixed to the stem ceramic 7 are
A spiral filament 1 is sandwiched between the upper and lower end shields 2 and 3 to be supported and fixed. The filament 1 is formed by spirally forming a thorium tungsten wire and carbonizing its surface. Since it is formed by performing a treatment to increase the radiation efficiency of thermoelectrons,
There has been a problem that the filament 1 is broken due to external vibration or impact.

As a solution to this problem, a magnetron cathode assembly as shown in FIG. 2 has been proposed. That is, in the figure, 9 is an insulating spacer for fixing the center lead 4 and the side lead 5 and for preventing displacement of the cathode due to external vibration or impact, and 10 is for preventing displacement of the insulating spacer 9. It is a metal ring brazed to the side lead 5.

In the cathode assembly having such a configuration, the center lead 4 and the side lead 5 have different lengths, so that resonance points are different from each other due to external vibration. Therefore, it has the effect of increasing the vibration resistance strength of the entire cathode structure.

However, in the cathode assembly having such a configuration, since the spacer 9 is positioned by welding and fixing the metal ring 10 to the side lead 5, the welding position is likely to be varied in work, and the position of the spacer 9 is consequently a filament. The closer to 1, the greater the vibration damping effect described above, but the variation in this position causes variations in the strength of filament 1. In addition, weak welding itself may occur, causing a defect that the metal ring 10 falls off. The spacer 9 should be installed closer to the filament 1, but if it is too close,
As described above, when the filament 1 is brazed, the temperature rise causes damage, which is a limitation. Further, at the time of assembly, since the seal member 8 becomes an obstacle for welding and fixing the metal ring 10 after the stem assembly is completed, the side lead 5, the center lead 4, and the spacer 9 must be pre-processed in advance. There was a problem of increasing the number of manufacturing processes.

[Object of the Invention]

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to improve workability and reliability and to improve vibration resistance strength against vibration given from all directions. To provide a magnetron cathode assembly.

[Summary of the Invention] In order to achieve such an object, in the magnetron cathode assembly according to the present invention, a sleeve is inserted through a side lead so that both ends thereof come into contact with a stem ceramic and an insulating spacer.

Example of Invention

 Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a cross-sectional view of the essential portions corresponding to FIGS. 1 and 2 showing an embodiment of the magnetron cathode structure according to the present invention. Omit it. In the figure, a thick stainless sleeve 11 is inserted between the spacer 9 and the stem ceramic 7 in the side lead 5 without welding.

With this structure, the spacer 9 is positioned by the break point of the center lead 4 and the sleeve 11 whose one end abuts on the stem ceramic 7, and the spacer 9 can be positioned with the dimensional accuracy of the sleeve 11. Therefore, it is possible to further reduce the variation in the vibration isolation effect of the center lead 4 and the side lead 5. Also,
Since the sleeve 11 itself is thicker than the metal ring 10 shown in FIG. 2, the weight thereof is significantly increased. Therefore, energy such as resonance of the center lead 4 and the side leads 5 is absorbed, and the same structure as that of FIG. Even at the position of the spacer 9 of 5, the higher reinforcing effect can be obtained against the disconnection of the filament 1. Further, the metal ring 10 as a fixing means of the spacer 9 shown in FIG. 2 uses an expensive Ni material in order to enhance the weldability, but the sleeve 11 shown in FIG. 3 does not require welding and is therefore inexpensive. Since stainless steel can be used, a low cost and high reinforcing effect can be obtained. Further, this sleeve 11 is simply inserted and fitted into the side lead 5 without welding the metal ring 10 to the side lead 5 as shown in FIG. This is possible, and the pre-processing and assembling and the welding process using jigs and tools for welding as described above are not required, so that the number of manufacturing steps of the magnetron cathode assembly can be significantly reduced.

〔The invention's effect〕

As described above, according to the magnetron cathode structure of the present invention, the sleeve is inserted through the side lead so that both ends of the side wall contact the stem ceramic and the insulating spacer, so that the cathode structure is protected from external vibration and shock. On the other hand, vibration resistance is improved, and the expensive molybdenum center leads and side leads can be made thinner without lowering the strength of the filament. Since the manufacturing process can be shortened, there is an extremely excellent effect that a cheaper magnetron can be obtained.

[Brief description of drawings]

FIG. 1 and FIG. 2 are cross-sectional structural views of an essential part showing an example of a conventional magnetron cathode structure, and FIG. 3 is a cross-sectional structural view of an essential part of an embodiment of a magnetron cathode structure according to the present invention. 1 …… Filament 2 …… Upper end shield 3 ……
Lower end shield, 3a ... Circular hole, 4 ... Center lead, 5 ... Side lead, 6 ... Power supply terminal, 7 ...
… Stem ceramics, 8 …… Seal parts, 9 …… Spacers, 11 …… Sleeves.

Claims (1)

[Claims] 1. A filament for emitting thermoelectrons, an upper end shield and a lower end shield fixedly arranged at the upper and lower ends of the filament, and a center lead having one end connected and fixed to the upper end shield.
A side lead whose one end is connected and fixed to the lower end shield, a stem ceramic in which the other ends of the center lead and the side lead are planted, and a center lead and a side lead which are inserted through these in order to keep them at a predetermined interval A magnetron cathode assembly including an insulating spacer, wherein a sleeve is inserted through the side lead so that both ends of the side ceramic abut on the stem ceramic and the insulating spacer.