JPH0214112Y2 - - Google Patents

Description

[Detailed description of the invention] This invention has sufficient vibration resistance and is designed to prevent characteristic deterioration due to changes in ambient temperature.
This invention relates to a traveling wave tube with an improved method of fixing the tube within a package.

Generally, in a traveling wave tube using a periodic magnetic field focusing device, a package structure is often used in which each part of the traveling wave tube is supported and fixed on a single board and the surrounding area is covered with a cover. An example of such a traveling wave tube is shown in FIG. In FIG. 1, a traveling wave tube 1 is housed in a package 4 consisting of a base plate 2 and a cover 3. As shown in FIG. The traveling wave tube tube 1 consists of an electron gun 5, a slow wave circuit 6 surrounded by a periodic magnetic field focusing device, a collector 7, and output sections 8 and 9. are supported and fixed on the substrate 2 by supports 10, 11, and 12, respectively. Input/output section 8, 9
A lead wire 13 for supplying input power is drawn out to the outside of the cover 3. In such a configuration, the heat generated in each part of the electron gun, slow wave circuit, and collector is conducted to the substrate 2 via the supports 10, 11, and 12, and is further transferred to a heat sink (not shown) to which the substrate 2 is attached. ) is transmitted by conduction. Such traveling wave tubes are required to have sufficient vibration resistance and temperature resistance so that their characteristics do not deteriorate due to vibrations and shocks during transport or use, as well as changes in ambient temperature.

Therefore, in order to meet these requirements, the support structure for each part must be such that each part is supported on the board with sufficient strength, the heat generated in each part can be sufficiently dissipated to the board, and the required surroundings can be maintained. It is required that the structure is such that deformation due to differences in thermal expansion of each member does not occur within a temperature range. In particular, electron guns must be prevented from bending due to vibration, shock, or changes in ambient temperature. If bending occurs, the electron beam will collide with the slow-wave circuit, which will not only deteriorate the electrical characteristics, but also cause gas release, deteriorating the vacuum inside the tube, and even cause local melting of the slow-wave circuit. This will cause it to become inoperable. In order to avoid such problems, various structures have been conventionally used to support the electron gun.

As an example, the structure shown in FIG. 2 is known. FIG. 2 shows the structure of the traveling wave tube near the electron gun, and the space between the electron gun 5 and the substrate 2 is filled with an insulating filler 14 such as silicone rubber. In such a configuration, the electron gun 5 is connected to the substrate 2
Since it is firmly fixed to the base, it has sufficient vibration resistance to withstand severe vibrations and shocks. Furthermore, the collector and slow wave circuit are also firmly fixed to the substrate for heat dissipation and vibration resistance. Therefore, due to differences in the coefficient of thermal expansion of each part of the traveling wave tube, the substrate, the support, etc., differences in the amount of thermal expansion occur in each part due to changes in ambient temperature, and as a result, the traveling wave tube This will cause the ball to bend slightly. However, if the length of the traveling wave tube is short, or if the diameter of the electron beam is sufficiently small compared to the diameter of the electron beam passage hole in the slow wave circuit and there is enough room for the beam to pass through, Even if a slight bend occurs in the wave tube bulb, beam transmission will not deteriorate, and therefore the above-mentioned problems will not occur. However, high frequency
When a traveling wave tube with high output, high gain, and high efficiency (interaction efficiency) is required, the length of the traveling wave tube becomes longer, or the diameter of the electron beam relative to the diameter of the electron beam passage hole is required. As the ratio increases, the beam transmission margin becomes smaller. In such cases, the curvature of the traveling wave tube sensitively affects beam transmission. That is, the beam transmission changes significantly within the required ambient temperature range, and the electrical characteristics no longer meet the required performance, or in worse cases, become inoperable.

Furthermore, as another conventional example, the structure shown in FIG. 3 is known. In this case, the metal member 15 on the slow wave circuit side of the electron gun 5 is placed on a pedestal 16 fixed to the substrate 2, and further held down from above by a metal band 17. Other parts of the electron gun 5 are covered with a filler 14 such as silicone rubber for electrical insulation, but are left open from the substrate 2. Similarly to the electron gun, the slow wave circuit 6 is placed on a pedestal 18 and is held down by a metal cover 19 from above. The collector 7 is firmly fixed to the substrate 2 via a support 12. In such a configuration, the electron gun 5 is supported by the pedestal 16, and is guided by the pedestal 16 and the metal band 16 so that it can slide on the pedestal 16 in the central axis direction. It's getting old. Therefore, even if a difference in thermal expansion occurs between each part of the traveling wave tube and the substrate due to a change in ambient temperature, the difference will be absorbed by the slow wave circuit 6 when the pedestal 18
This can be absorbed by sliding the electron gun 5 on the pedestal 16, so that the traveling wave tube does not bend. In other words, the characteristics do not deteriorate due to changes in ambient temperature.
In this case, the electron gun pedestal 16 and the slow wave circuit pedestal 18
Needless to say, the relative positions of the traveling wave tubes must be precisely aligned so that the central axis of the traveling wave tube can be supported without bending. However, in this structure, the electron gun is supported on the slow wave circuit side, so the electron gun is likely to bend around this support position due to vibrations and shocks. In particular, such a support structure is insufficient when severe conditions are required for vibration and shock, such as when mounted on a satellite.

The object of this invention is to provide a traveling wave tube which eliminates all of these conventional drawbacks.

According to this invention, it is possible to obtain, by a simple method, a traveling wave tube having a support structure for an electron gun that can withstand severe vibration and impact conditions and that does not cause characteristic deterioration even with changes in ambient temperature. .

Next, this invention will be explained using examples. Fourth
The figure shows an embodiment of this invention, in which a metal or insulating cylinder 20 is arranged around the electron gun 5,
The space between the cylinder 20 and the electron gun 5 is filled with an insulating filler 14 such as silicone rubber. Then, a second cylinder 21 made of metal or an insulator is disposed outside this cylinder 20, and this second cylinder 21 is made of metal or an insulator and fits therein.
The space between the second cylinder 21 and the substrate 2 is filled with an adhesive filler 22, and the second cylinder 21 is adhered and fixed to the substrate 2. The slow wave circuit 6 and the collector 7 are supported on a substrate (not shown) as in the conventional example shown in FIG.

In such a configuration, the first cylinder 20 is fixed to the electron gun 5 via the insulating filler 14, and is guided by the second cylinder 21 in the central axis direction and slides inside the second cylinder 21. can do. Therefore, if a difference in thermal expansion occurs between each part of the traveling wave tube and the substrate due to a change in ambient temperature, this difference will cause the slow wave circuit 6 to move over the pedestal 18 and the electron gun. 5 is absorbed by sliding inside the second cylinder 21, so that no bending occurs in the traveling wave tube. However, in this case, the second cylinder 2
1 and the slow wave circuit pedestal 18 must be precisely aligned in height from the substrate 2 and in a direction perpendicular to the longitudinal direction on the substrate 2 so that the central axis of the traveling wave tube does not bend. be. In the case of this invention, unlike the conventional example shown in FIG. 3, in which the electron gun holder 16 is directly attached to the substrate 2, the second cylinder 21 is fitted into the first cylinder 20, and then the Since the space between the second cylinder 21 and the substrate 2 is filled with an adhesive filler 22 to adhere and fix the second cylinder 21 to the substrate 2, the relative positional relationship between the second cylinder 21 and the slow wave circuit pedestal 18 can be determined. It can be matched easily and precisely. Therefore, the characteristics do not deteriorate due to changes in ambient temperature.

Furthermore, in this invention, the second cylinder 21 can be placed at any position in the longitudinal direction of the substrate 2 so as to support the vicinity of the center of gravity of the electron gun 5. Therefore, by supporting the vicinity of the center of gravity of the electron gun, it is possible to sufficiently withstand vibrations and shocks. Furthermore, the first and second cylinders 20, 21
By selecting a material with good thermal conductivity for the adhesive filler 22, it is also possible to improve the dissipation of heat generated by the electron gun by conduction to the substrate.

As is clear from the above description, according to this invention, a traveling wave tube with excellent temperature characteristics and vibration/shock resistance can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram for explaining the structure of a traveling wave tube, Fig. 2 is a partially cutaway cross-sectional view showing the structure near the electron gun of a conventional traveling wave tube, and Fig. 3 is a schematic diagram for explaining the structure of a conventional traveling wave tube. FIG. 4 is a partially cutaway sectional view showing the structure. FIG. 4 is a partially cutaway sectional view showing the main part of the embodiment of this invention. 2...Package board, 5...Electron gun, 6...
Slow wave circuit, 7... Collector, 14... Insulating filler, 20... Cylinder, 21... Cylinder (second cylinder),
22...Adhesive filler.

Claims (1)

[Scope of utility model registration request] A cylinder is disposed around the electron gun, and a second cylinder is fitted into the cylinder, the inside of which is filled with an insulating filler so as to be able to slide outward in the axial direction.
A traveling wave tube having an electron gun support structure in which a cylinder is fixed to the package substrate by filling an adhesive filler into the gap between the cylinder and the package substrate.