JPH0521012A - Collector body structure for microwave tube - Google Patents

Abstract

PURPOSE:To provide the collector body structure of a microwave tube capable of stabilizing its signal amplification function and reducing its weight having firm structure to external force, and improving reliability. CONSTITUTION:Plural collector electrode 3, 4, 5, and 6 have funnellike parts 3a, 4a, 5a, and 6a and cylindrical parts 3b, 4b, 5b, and 6b in the collector body structure of a microwave tube. The end part of each cylindrical part is solder- supported with a ceramic envelope 8 and is surrounded with a cylindrical metallic envelope 10 continued to the ceramics envelope, and moreover a metallic support cylinder 11, having wall thickness thinner than that of the metallic envelope, is airtightly joined between the metallic envelope and a connecting end plate 1 connected to a high-frequency operation part.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Generally, in a microwave tube, a high frequency acting section such as a slow wave circuit and a collector structure are arranged downstream of an electron beam of an electron gun section. For example, a traveling wave tube mounted on an artificial satellite employs a multi-stage collector structure in which a collector potential is lowered to operate in order to improve power utilization efficiency.

This type of collector structure is conventionally constructed as shown in FIG. 7, and reference numeral 21 in the figure is a connection end plate connected to a high-frequency acting portion (not shown). A collector support ring 24 is provided via a plurality of support cylinders 22 and a high thermal resistance vacuum bellows 23. The collector support ring 24 includes a plurality of support rods 2
5, 25 ... Are projected in a circle shape at equal intervals.
Insulation pipes 26 are provided on the outer circumferences of the support rods 25, respectively.
The insulating cylinders 27, 28, 29, 30, and 31 are fitted to each other via and are fixed together with the heat transfer support plate 32 by a fixing nut 33.

A funnel-shaped heat shield plate 34 is arranged near the connecting end plate 21 along the tube axis, and its peripheral edge portion is sandwiched between and fixed to the collector supporting disk 24 and the insulating cylinder 27. . The funnel-shaped first, second, third and fourth collector electrodes 35, 36, 37, 38 and the bottom electrode 39 of the fourth collector electrode 38 are coaxial with the heat shield plate 34 and the electron beam upstream side. Are arranged in a row at a predetermined interval in the downstream side from each of the flanges, and the flange portions are attached to the supporting rods 25, 25 ...
It is sandwiched and fixed via 8, 29, 30, 31. Further, each collector electrode 35, 36, 37, 38, bottom electrode 39 and support rod 25, 25 ..., Insulating cylinder 27, 2
Collector envelope 4 so as to surround 8, 29, 30, 31, etc.
0 is provided and is fixed to the collector support disk 24.

[0005]

In normal operation,
The radiation-cooled collector structure radiates a large amount of heat from a small surface area, so that the collector envelope 40 has about 200 to 30.
Used at a high temperature of 0 ° C. On the other hand, the traveling wave tube main body needs to be kept at about 20 to 40 ° C., and a heat insulating structure is required between the collector structure and the traveling wave tube main body. Therefore, the emergence of a radiation-cooled collector structure, which has excellent heat insulating properties and a simple structure and a high support strength of the collector electrode, is desired.

The present invention has been made in order to satisfy the above-mentioned demands. It has excellent heat insulation properties, can stabilize the signal amplification function, can be reduced in weight, and has a structure that is strong against external force and is reliable. It is an object of the present invention to provide a collector structure for a microwave tube that also improves performance.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a plurality of collector electrodes each have a funnel-shaped portion and a cylindrical portion, each cylindrical end portion being brazed and supported by a ceramic envelope, and the cylindrical portion. The end is surrounded by a cylindrical metal envelope that is continuous with the ceramic envelope, and the wall thickness between the metal envelope and the connection end plate connected to the high-frequency working portion is thinner than the thickness of the metal envelope. It is a collector structure of a microwave tube in which a metal supporting cylinder is hermetically joined.

[0008]

According to the present invention, the heat insulating property is excellent, the signal amplifying function can be stabilized, the weight can be reduced, and the structure is robust against external force and the reliability is also improved.

[0009]

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

That is, reference numeral 1 in FIG. 1 is a connecting end plate connected to a high-frequency acting portion (not shown).
A funnel-shaped heat shield plate 2 is arranged along the tube axis at a predetermined interval. Furthermore, corresponding to this heat shield plate 2,
The first, second, third and fourth collector electrodes 3, 4, 5, 6 and the bottom electrode 7 of the fourth collector electrode 6 are coaxially arranged in series from the upstream side to the downstream side of the electron beam at a predetermined interval. Has been done. First, second, third and fourth collector electrodes 3, 4, 5,
Each of 6 is composed of funnel-shaped portions 3a, 4a, 5a, 6a and cylindrical portions 3b, 4b, 5b, 6b.
The ends of b, 5b, 6b are brazed to the inner surface of the ceramic envelope 8 in the direction perpendicular to the tube axis, and are joined and held by heat transfer and mechanically. In this case, a plurality of ring-shaped concavities and convexities 9 are concentrically formed on the inner surface of the ceramic envelope 8 and the ends of the cylindrical portions 3b, 4b, 5b, 6b are located in the ring-shaped recesses and brazed. ing. Further, the bottom electrode 7 of the fourth collector electrode 6 is brazed in close contact with the central portion of the inner surface of the ceramic envelope 8 as shown in the figure.

Further, each of the cylindrical portions 3b, 4b, 5b and 6b is surrounded by a cylindrical metal envelope 10, and a metal supporting cylinder 11 is ring-shaped between the metal envelope 10 and the connecting end plate 1. It is airtightly joined via the joining member 12. The metal supporting cylinder 11 is made of a material having a low thermal conductivity, such as stainless steel, titanium, or Kovar (trade name), and its thickness is thinner than that of the metal envelope 10, preferably 0.2.
The thickness is set in the range of 0.5 mm. The length in the tube axis direction is preferably set within the range of 10 to 60 mm. The peripheral portion of the heat shield plate 2 is brazed and supported by the ring-shaped joining member 12.

In the above case, the material of the ceramic envelope 8 is beryllia (BeO) or alumina (Al).
₂ O ₃ ) is used, and as the material of the metal envelope 10, for example, Kovar, which is easy to bond with ceramics, is used, and the thickness thereof may be in the range of 0.7 to 1 mm. The material of the ring-shaped joining member 12 is stainless steel or kovar.

During operation, electron beams are captured by the collector electrodes 3, 4, 5 and 6, but each electrode generates heat at that time. For this reason, the temperature of the metal envelope 10 also rises, and the heat is mainly radiated from the ceramic envelope 8 to the outer space, but a part of the heat is conducted through the metal supporting cylinder 11 to the connecting end plate 1. Flowing. However, in the present invention, since the metal supporting cylinder 11 is a thin plate and is made of a material having a small thermal conductivity, it is possible to suppress the heat conduction toward the high frequency acting portion through this. In the simulation by the present inventors, it was confirmed that the heat conduction in the direction of the high frequency acting portion was reduced to about 1/3 in the embodiment of the present invention as compared with the structure of FIG.

Further, in the conventional example shown in FIG. 7, the functions of heat insulation and collector electrode holding are provided by the support cylinder 22 and the vacuum bellows.
However, in the present invention, the metal supporting cylinder 11 has both a heat insulating function and a collector electrode holding function. As a result, a sufficiently large transverse rupture strength is obtained and the weight is about 1 / th compared to that of FIG.
Could be reduced to 5.

FIG. 2 shows a second embodiment of the present invention.
That is, the first, second, third and fourth collector electrodes 3, 4,
5 and 6, each of the cylindrical portions 3b, 4b, 5b, 6b has a concave portion 13 for ventilation and thermal strain dispersion as shown in the horizontal sectional view (a) of FIG. 3 and the vertical sectional view (b) thereof. The insulating ceramic rings 14, 15, 16 and 17 are mechanically held at predetermined intervals. In this embodiment, the ceramic rings 14, 15, 16, 17 and the cylindrical portions 3b, 4b, 5b, 6b and the metal envelope 10 are
It is joined by brazing. By adopting the ceramic rings 14, 15, 16, 17, the first, second,
The positional accuracy of the third and fourth collector electrodes 3, 4, 5, 6 and the mechanical strength of these assemblies are improved. The recess 13
Instead of, a slit or a through hole may be formed. Except for the ceramic rings 14, 15, 16 and 17, the structure is the same as that of the first embodiment.

FIG. 4 shows a third embodiment of the present invention. Instead of the metal supporting cylinder 11 in each of the above embodiments, a metal supporting cylinder 18 shown in FIG. 4 may be used. FIG. 5 is an enlarged sectional view showing A in FIG. 5, and FIG. 6 is an enlarged sectional view showing B. In order to maintain a high bending strength, a ring-shaped convex portion 19 and a shaft in the circumferential direction are provided. Directional protrusions 20 are provided.

[0017]

According to the present invention, each of the plurality of collector electrodes has a funnel-shaped portion and a cylindrical portion, and the end portion of each cylindrical portion is brazed and supported by the ceramic envelope, and the end portion of the cylindrical portion is also provided. Is surrounded by a cylindrical metal envelope continuous with the ceramics envelope, and a metal support thinner than the thickness of the metal envelope is further provided between the metal envelope and the connecting end plate connected to the high-frequency working portion. Since the cylinders are airtightly joined, there are the following advantages.

(1) The heat flow rate from the collector structure to the traveling wave tube main body side is reduced, and the temperature rise of the electron beam focusing magnet incorporated in the traveling wave tube is reduced. Magnetic field fluctuations are reduced. Therefore, the change in the orbit of the electron beam becomes small, and the signal amplification function of the traveling wave tube is stabilized. (2) The structure of the collector can be reduced in weight, and the structure is robust against external forces such as vibration and acceleration. (3) Reliability is improved because the structure is simple and the number of parts is small.

[Brief description of drawings]

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

FIG. 2 is a vertical sectional view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing a ceramic ring used in a second embodiment.

FIG. 4 is a perspective view showing a third embodiment of the present invention.

FIG. 5 is an enlarged sectional view showing a main part of the third embodiment.

FIG. 6 is an enlarged cross-sectional view showing a main part of the third embodiment.

FIG. 7 is a cross-sectional view showing a collector structure of a conventional microwave tube.

[Explanation of symbols]

1 ... end plate for connection, 3, 4, 5, 6 ... Collector electrode, 3a, 4a, 5a, 6a ... Funnel-shaped portion, 3b, 4b, 5b, 6b ... Cylindrical part, 8 ... Ceramic envelope, 10 ... Metal envelope, 11 ... Metal supporting cylinder.

Claims (2)

[Claims] 1. A collector structure of a microwave tube in which a plurality of collector electrodes are vertically arranged at a predetermined interval, wherein each of the plurality of collector electrodes has a funnel-shaped portion and a cylindrical portion, and an end portion of each cylindrical portion. Is brazed to and supported by a ceramics envelope, and the end of the cylindrical portion is surrounded by a cylindrical metal envelope that is continuous with the ceramics envelope. A collector assembly for a microwave tube, characterized in that a metal supporting cylinder thinner than the thickness of the metal envelope is airtightly joined to the end plate. 2. The collector structure for a microwave tube according to claim 1, wherein each of the plurality of collector electrodes has a cylindrical portion held at predetermined intervals by a ceramic ring having a recess or a through hole.