JPH04277444A - Structure of collector of microwave tube - Google Patents

Abstract

PURPOSE:To eliminate risk of melting and vaporization of a metal of the surface where an electron beam runs against, equip the whole collector with an excellent heat emitting characteristic relieve thermal stresses on the way, lessen the risk of breakage, and construct the whole structure in light weight. CONSTITUTION:The collector structure of a microwave tube is configured so that collector electrodes 5-8 are formed from an inclining functional material in which the contents of W/Mo and Cu vary gradually, and also that the W or Mo is situated on the side which is bombarded with electron beam. Thus the intended purpose will be achieved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collector structure for a microwave tube suitable for use in traveling wave tubes, klystrons, and the like.

0002

2. Description of the Related Art Generally, a microwave tube has a high frequency acting section such as a slow wave circuit and a collector structure arranged downstream of an electron beam of an electron gun section. For example, traveling wave tubes mounted on artificial satellites employ multistage collector structures that operate by lowering the collector potential in order to increase power usage efficiency.

In this type of collector structure, a plurality of collector electrodes are stacked and fixed while being electrically insulated by a ring-shaped insulating support such as ceramic. These collector electrodes and insulating supports are covered by a collector envelope, which is a surrounding member. By the way, there are three types of materials that have been conventionally used for the collector electrode and the collector envelope as described below. (1) Each collector electrode is made of tungsten (W) or molybdenum (Mo). (2) Each collector electrode is made of copper (Cu). (3) The collector envelope is made of stainless steel and Kovar (product name).

0004

[Problems to be Solved by the Invention] However, when the above materials are used, the following problems occur. Above (1)
In this case, heat conduction is poor, and if the material is made thicker to improve heat conduction, it will become heavier.

In the case of (2) above, the mechanical strength is weak;
If you make the material thicker to increase its mechanical strength, it will become heavier. Furthermore, when the mechanical strength is increased, cracks occur in the ceramic due to the difference in thermal expansion between the insulating support and the ceramic. In the case of (3) above, heat conduction is poor and there is a large difference in thermal expansion between the collector electrode and the collector envelope.

The present invention solves the above-mentioned disadvantages, and provides a collector structure for a microwave tube that has excellent heat dissipation characteristics, reduces the risk of breakage due to thermal stress being alleviated midway, and is lightweight as a whole. The purpose is to provide

[0007]

[Means for Solving the Problems] In the present invention, the collector electrode is made of a functionally graded material in which the contents of W or Mo and Cu gradually change, and the W or Mo is located on the side that is hit by the electron beam. This is the collector structure of a microwave tube.

[0008]

[Operation] According to this invention, there is no fear that the metal on the surface that is hit by the electron beam will melt or evaporate, and the heat conductivity from the W or Mo surface that is hit by the electron beam to the Cu is good, so the heat is dissipated from the entire collector. It has excellent properties and reduces the risk of breakage because thermal stress is alleviated during the process, making it possible to reduce the overall weight.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. The embodiment shown in FIG. 1 is an application of the present invention to a helical traveling wave tube, and is constructed as follows.

That is, the reference numeral 1 in the figure is a connecting end plate connected to a high frequency action section (not shown), and this connecting end plate 1
A collector support plate 4 is provided through a high heat resistance bellows 2 and a thin support cylinder 3. and the funnel-shaped first
, second, third, and fourth collector electrodes 5, 6, 7, and 8, and a bottom electrode 9 of the fourth collector electrode 8 are arranged at predetermined intervals from the upstream side to the downstream side of the electron beam, and are each made of a ring-shaped ceramic material. They are electrically insulated and stacked on top of each other by insulating supports 10, 11, 12, and 13, and are fixed to the collector support plate 4. Each collector electrode and the insulating support are brazed. Furthermore, these plurality of collector electrodes 5,
6, 7, 8 and a bottom electrode 9 and an insulating support 10, 11,
12 and 13 are covered by collector envelopes 14 and 15, and the bottom electrode 9 is held by the collector envelope 15 via a disc-shaped insulating support 16.

In the above case, each collector electrode 5, 6, 7,
8 and the bottom electrode 9, as shown enlarged in the circle in FIG. 1, are both made of a functionally graded material in which the content of W (tungsten) or Mo (molybdenum) and Cu (copper) gradually changes. In addition, W or Mo is located on the side that is hit by the electron beam. For convenience, only the first collector electrode 5 is shown enlarged in a circle in FIG. 1, but the other collector electrodes 6
, 7, 8 and the bottom electrode 9, needless to say, the same is true.

[0012] Here, the functionally graded material will be explained as follows.
Generally, when two materials A and B are joined together, the advantages of both materials can be utilized, but the disadvantage is that they are prone to bending and peeling due to the difference in coefficient of thermal expansion. However, functionally graded materials gradually change the quality of the material from A to B at the interface to solve the above-mentioned problems. For details, please refer to the magazine "Industrial Materials" Vol. 38, No. 12, No. 14 (January 1990).
Published in October and November of the same year). In this embodiment, the first, second, third, and fourth collector electrodes 5
, 6, 7, 8, and the bottom electrode 9 of the fourth collector electrode 8, the functionally graded material described above is used. As a result of employing such a functionally graded material, the present invention provides the following excellent effects when compared with the prior art. Compared to (1) described in the prior art, this embodiment is lighter when heat conduction is the same. Compared to (2), this embodiment is lighter when the mechanical strength is the same. Compared to (2), even if the mechanical strength is increased, the difference in thermal expansion is small, so cracking of the ceramic is less likely to occur. Compared to (3), this example has better heat conduction. Compared to (3), this embodiment has a smaller difference in thermal expansion between the collector electrode and the collector envelope. (Other Embodiments) Next, other embodiments of the present invention will be described, and the same effects as those of the above embodiments can be obtained.

First, referring to the embodiment shown in FIG. 2, in the collector structure shown in FIG.
The peripheral edges of the third and fourth collector electrodes 17, 18, 19, 20 and the bottom electrode 21 are respectively connected to the ring-shaped insulating support 2.
2, 23, 24, 25 and a disc-shaped insulating support 26, and are fixed to the collector envelopes 27, 28 by brazing. And, just like the above embodiment, each collector electrode 17, 18, 19, 20 and the bottom electrode 21 are made of a functionally graded material. Furthermore, in this embodiment, the collector envelopes 27 and 28, which are enclosing members, are each made of a functionally graded material in which the contents of W or Mo and Cu gradually change, as shown in the enlarged circles. In addition, W or Mo is located on the side that is hit by the electron beam. For convenience, only the collector envelope 27 is shown enlarged in a circle in FIG. 2, but it goes without saying that the same is true for the collector envelope 28 as well.

Next, referring to the embodiments shown in FIGS. 3(a) and 3(b), the collector structure shown in FIGS. A cylindrical collector envelope 34 is provided through insulators 30, 31, 32, and 33. In this case, the collector envelope 34 is made of W or Mo and Cu as shown enlarged in the circle.
It is composed of a functionally graded material whose content gradually changes.
In addition, W or Mo is located on the side that is hit by the electron beam. Therefore, if the temperature of the collector electrode 29 rises during operation,
Due to the difference in thermal expansion between the collector electrode 29 and the collector envelope 34, the collector electrode 29, the insulators 30, 31, 32, 3
3. The contact of the collector envelope 34 is improved, and heat conduction is improved.

Next, regarding the embodiment shown in FIG. 4, the collector structure shown in FIG. A radiator 37 is provided protrudingly. in this case,
The collector electrode 35 is made of a functionally graded material in which the contents of W or Mo and Cu gradually change, and W or Mo is located on the side that is hit by the electron beam. Furthermore, radiator 3
7 is made of Cu.

Finally, referring to the embodiment shown in FIG.
The collector structure in FIG. 5 is also not a multi-stage type, and an inverted U-shaped tightening member 40 is provided on the outer periphery of the collector electrode 38 with a cylindrical ceramic insulator 39 interposed therebetween. It is fixed to a base plate 42 with screws 41. In this case, as in the embodiment shown in FIG.
o is located on the side that is hit by the electron beam. Furthermore, the tightening member 40 is also made of W or Mo and C as shown enlarged in the circle.
It is made of a functionally graded material whose content gradually changes, but contrary to the collector electrode 38, Cu is located on the inside and W or Mo is located on the outside. Therefore, if the temperature of the collector electrode 38 rises during operation, the collector electrode 38
The difference in thermal expansion between the insulator 39 and the insulator 39 improves the contact between the two, making it difficult for the insulator 39 to be damaged. Reference numeral 43 in the figure represents a heat transfer member. Note that the collector electrode in each of the above embodiments may be coated with carbon, titanium carbide, titanium nitride, or the like on all or part of its surface, if necessary.

[0017]

[Effects of the Invention] According to the present invention, the collector electrode includes W
Or, since it is composed of a functionally graded material in which the contents of Mo and Cu gradually change, and W or Mo is located on the side that is hit by the electron beam, there is a risk that the metal on the side that is hit by the electron beam will melt or evaporate. There is no. Also, W or M where the electron beam hits
Since heat conductivity is good from o to Cu, the heat dissipation characteristics of the entire collector are excellent. Furthermore, since the thermal stress is relieved during the process, there is less risk of breakage. Moreover, the weight of the entire collector structure can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a collector structure of a microwave tube according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a collector structure of a microwave tube according to a first other embodiment of the present invention.

FIGS. 3(a) and 3(b) are a vertical cross-sectional view and a cross-sectional view showing a collector structure of a microwave tube according to a second other embodiment of the present invention, and FIG. Cut along line A-A' and viewed in the direction of the arrow.

FIG. 4 is a cross-sectional view showing a collector structure of a microwave tube according to a third other embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a collector structure of a microwave tube according to a fourth alternative embodiment of the present invention.

[Explanation of symbols]

5-8... Collector electrode, 10-13... Insulating support, 14
, 15... Collector envelope.

Claims (1)

[Claims] 1. A collector structure of a microwave tube having a collector electrode disposed downstream of an electron beam of a high frequency working part, wherein the collector electrode is made of W or Mo and Cu.
It is composed of a functionally graded material whose content gradually changes.
A collector structure for a microwave tube, wherein the W or Mo is located on a side that is hit by the electron beam.