JPH07101595B2 - Microwave tube collector structure - Google Patents

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 in an electron gun section. For example, a traveling-wave tube mounted on an artificial satellite employs a potential-decreasing collector structure that operates by lowering the collector potential below the potential of the high-frequency action section in order to improve power utilization efficiency.

This type of collector structure is conventionally constructed as shown in FIG. 5 and FIG.
Reference numerals 3 and 4 denote first, second, third, and fourth collector electrodes arranged in series along the tube axis, and their peripheral edge portions (flange portions) 1a, 2a, 3a, and 4a are ceramic electrode columns 5. , 6, 7, 8, 9 are electrically insulated and held from each other. In addition, 10 is an end plate for connection connected to the high frequency acting part,
Reference numeral 11 is a heat shield plate, 12 is a support cylinder, 13 is a collector support substrate, 14 is a heat transfer support plate, 15 and 16 are ceramic electrode columns, and 17 and 18 are vacuum envelopes.

(1) As described above, the plurality of collector electrodes 1, 2, 3, 4 are made of ceramic electrode columns 5, 6,
7, 8, and 9 are electrically insulated from each other and stacked and fixed. Further, there is one in which a washer made of a soft metal such as copper is sandwiched between the collector electrode and the ceramic electrode support, and the washer is tightened to improve the contact property and the heat radiation property (Shokai Sho 61-119240). issue). (2) Further, in order to further improve heat dissipation, a structure in which the peripheral edge of the collector electrode and the ceramic electrode support are brazed is also known. In this case, for the collector electrode, (a) choose a metal whose coefficient of thermal expansion is close to that of ceramics, or (b) reduce the thickness of the joint or make a notch to reduce the stress of ceramics due to the difference in thermal expansion. It is necessary to prevent the ceramics from cracking during brazing by using a method such as relaxation.

[0005]

However, the conventional collector structure as described above has the following disadvantages.
In the case of (1) above, the contact between the ceramic and the washer is not perfect, and there is a contact resistance between the ceramic and the washer or between the ceramic and the collector electrode, so the heat dissipation is poor. Further, since the components are tightened and fixed, thermal expansion during operation may rub the contact portion to generate fine metal powder, impairing withstand voltage characteristics. In the case of the above (2)-(a), heat dissipation is impaired because the metal (cobal etc.) having a thermal expansion coefficient close to that of the ceramic has a small thermal conductivity. In case of (2)-(b) above,
Originally, the purpose is to weaken the strength of the component and to relieve the thermal stress, so the mechanical strength of the collector structure may be reduced.

The present invention has been made to solve the above-mentioned inconveniences, and an object of the present invention is to provide a collector structure for a microwave tube which is excellent in heat radiation characteristics, mechanical strength, and withstand voltage characteristics.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a plurality of collector electrodes are vertically arranged in a collector vacuum envelope along a tube axis at predetermined intervals, and their peripheral portions are electrically connected to each other by ceramic electrode columns. A collector structure of a microwave tube which is insulated and held, and a metal spacer is brazed to each end face of adjacent electrode columns, and the peripheral edge of the collector electrode is sandwiched between these spacers. is there.

[0008]

According to the present invention, the heat dissipation characteristics of the collector electrode,
Excellent mechanical strength and withstand voltage characteristics.

[0009]

DETAILED 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 helix type traveling wave tube, and is configured as follows.

That is, if the same parts as those in the conventional example (FIG. 5) are designated by the same reference numerals, the reference numeral 10 in the figure is a connecting end plate connected to a high frequency acting part (not shown). Through the support cylinder 12 to the collector support substrate 1
3 is provided. Further, a funnel-shaped heat shield plate 11 is arranged along the tube axis at a predetermined distance from the connection end plate 10. Corresponding to this heat shield plate 11, first, second,
The third and fourth collector electrodes 1, 2, 3, 4 are coaxially arranged in a row at a predetermined interval from the upstream side of the electron beam to the downstream side,
The respective peripheral edge portions (flange portions) 1a, 2a, 3a, 4a are insulated from each other and held by ceramic electrode columns 5, 6, 7, 8, 9.

In this case, as is apparent from FIG. 2, for example, when holding the peripheral edge portion 1a, metal spacers 19 and 20 are brazed to the end faces of the adjacent electrode columns 5 and 6, respectively. A peripheral edge portion 1a of the collector electrode 1 is held between the spacers 19 and 20. The peripheral portion 1a, that is, the collector electrode 1 is made of copper, and the spacers 19 and 20 are made of a metal having a coefficient of thermal expansion at brazing temperature smaller than that of copper and larger than that of ceramics, for example, an iron-nickel alloy such as kovar. In addition, also in the case of the other peripheral portions 2a, 3a, 4a,
It is retained exactly as above. The peripheral portions 11a of the heat shield plate 11 and the collector support substrate 13 are also the spacers 19 and 20 on the end faces of the electrode columns 5 and 15 in the same manner as above.
It is held between (not shown in the figure for convenience). Further, the heat transfer support plate 14 fixed to the collector vacuum envelopes 17 and 18 also has the electrode columns 9 and 16 similarly to the above.
It is held between spacers 19 and 20 (not shown in the figure for convenience) of the end faces.

In the above-mentioned embodiment, as is apparent from the figure, a convex portion is formed at one end of the electrode pillar and a concave portion is formed at the other end thereof, and the convex portion penetrates the peripheral portion of the collector electrode and the spacer. , Are fitted and positioned in the recesses of the adjacent electrode columns.

As a result of the above construction, the coefficient of thermal expansion decreases in the order of the collector electrodes 1, 2, 3, 4, spacers 19, 20, ceramic electrode columns 5, 6, 7, 8, 9. Since the stress generated on the electrode columns 5, 6, 7, 8, 9 is small, compared to the case where the collector electrodes 1, 2, 3, 4 and the electrode columns 5, 6, 7, 8, 9 are directly brazed. The electrode columns 5, 6, 7, 8 and 9 are unlikely to crack. Therefore, it is not necessary to thin the collector electrodes 1, 2, 3, 4 or make notches to reduce the strength.
It also has excellent mechanical strength. Further, since the spacers 19 and 20 may be extremely thin, the decrease in heat conduction is negligible. Further, the electrode columns 5, 6, 7, 8, 9 and the spacer 1
Between 9 and 20, or the electrode columns 5, 6, 7, 8, 9
Since no electrical gap is generated between the collector electrodes 1, 2, 3, and 4, a large local electric field is not generated by the induction of the electrode columns 5, 6, 7, 8, and 9. Therefore, discharge is unlikely to occur and the withstand voltage characteristic is improved. Due to the existence of the spacers 19 and 20, collector electrodes 1, 2, and
The heat transfer between the electrodes 3, 4 and the electrode columns 5, 6, 7, 8, 9 is improved. (Other embodiments)

3 and 4 are other embodiments of the present invention, and the same effects as the above embodiments can be obtained. That is, although the metal spacers 19 and 20 are plate-shaped in the above embodiment, cup-shaped metal spacers 21 and 22 may be used as shown in FIG. The cup-shaped metal spacers 21 and 22 have an electric field shielding function and can improve withstand voltage characteristics.

As described above, the embodiment of FIG. 1 has a shape in which the convex portion is formed at one end of the electrode column and the concave portion is formed at the other end, and the convex portion is fitted into the concave portion of the adjacent electrode column. But
As shown in FIG. 4, the electrode support 2 has a flat end surface without unevenness.
3,24,25,26,27 and metal spacers 28,2
You may use 9,30.

[0016]

According to the present invention, the metal spacers are brazed to the respective end faces of the adjacent electrode columns, and the peripheral portion of the collector electrode is sandwiched between the spacers. , It is possible to provide a microwave tube collector structure having excellent mechanical strength and withstand voltage characteristics.

[Brief description of drawings]

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

FIG. 2 is an enlarged cross-sectional view showing a main part of FIG.

FIG. 3 is a sectional view showing a main part according to another embodiment of the present invention.

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

FIG. 5 is a cross-sectional view showing a collector structure of a conventional microwave tube.

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

[Explanation of symbols]

1, 2, 3, 4 ... Collector electrodes 1a, 2a, 3a, 4
a ... peripheral part, 5, 6, 7, 8, 9 ... electrode support column, 17, 1
8 ... Collector vacuum envelope, 19, 20 ... Spacer.

Claims (2)

[Claims] 1. A microwave in which a plurality of collector electrodes are arranged in series in a collector vacuum envelope along a tube axis at predetermined intervals, and each peripheral portion is electrically insulated and held by ceramic electrode columns. In the collector structure of the tube, a metal spacer is brazed to each end face of the adjacent electrode columns, and the peripheral portion of the collector electrode is sandwiched between the spacers. Tube collector structure. 2. The collector structure for a microwave tube according to claim 1, wherein the spacer is made of a metal having a coefficient of thermal expansion higher than that of ceramics at a brazing temperature.