JP2978816B2 - Radiation cooled traveling wave tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation cooling type traveling wave tube having a radiation cooling fin on the outer periphery of a collector, and more particularly, to an improvement in radiation cooling effect in a high temperature environment and prevention of supercooling in a low temperature environment to improve reliability. The present invention relates to a radiation-cooled traveling-wave tube that can improve the performance.

[0002]

2. Description of the Related Art Traveling-wave tubes are used for microwave amplification in microwave satellite communications. In particular, for traveling wave tubes used in satellite transponders, in addition to small size, light weight and high efficiency, vibration and shock applied during launching of rockets, attitude control of satellites, etc., and operation of satellites It is required to have a performance that can withstand a severe environment such as a temperature cycle in which a temperature difference greatly varies depending on the environment.

On the other hand, a traveling wave tube generates heat of 100 W or more, and generates a large amount of heat among devices used for a repeater of an artificial satellite. For this reason, the heat dissipation design of a traveling wave tube is an important matter for a satellite.

[0004] There are a conduction cooling type and a radiation cooling type as a heat dissipation control method for a traveling wave tube mounted on a satellite. In the conduction cooling type, heat generated in the collector of the traveling wave tube is transmitted to the main body of the satellite by conduction, and is radiated to outer space by a heat treatment mechanism of the satellite. On the other hand, in the radiation cooling type, a radiation fin is attached to the collector of the traveling wave tube in a state where the radiation fin is exposed to outer space, and heat generated in the collector is directly radiated from the radiation fin to outer space by radiation.

An advantage of the radiation cooling type is that the heat generated in the collector is not transmitted to the satellite, so that the heat treatment capacity of the satellite can be small. For this reason, it is said that this radiant cooling type will be the mainstream in the next generation traveling wave tube. In the case of higher output, the heat generated from the collector increases, so the radiant cooling type has a structure in which the heat radiation part of the collector is exposed to outer space and heat is released, rather than the conduction cooling type that radiates heat from the collector to the inside of the satellite through the substrate surface. Is more suitable.

First, a helical traveling wave tube will be described as a conventional radiation cooled traveling wave tube with reference to FIG.

As shown in the block diagram of FIG. 5, an electron gun 91 of a traveling wave tube 90 transmits an accelerated electron beam to a slow wave circuit 92.
Radiate to The slow-wave circuit 92 gradually amplifies and outputs a separately input microwave as the interaction of the incident electron beam progresses, and outputs the electron beam that has completed the interaction with the microwave to the collector 3. .

[0008] The collector 3 captures the input electron beam by the collector electrode 93, and the heat generated at this time is
The heat is radiated to outer space by a plurality of radiating fins 94 arranged in the meridian direction around the outer periphery of the cylindrical collector 3. The heat dissipated by the radiation fins 94 toward the traveling wave tube is blocked by a heat shield 95 provided between the collector 3 and the slow wave circuit 92 in a plane.

Next, with reference to FIG. 6, a description will be given of heat dissipation of the radiation-cooled traveling wave tube in the satellite.

A traveling wave tube 90 shown in the configuration explanatory view of FIG. 6A is provided with radiation fins 94 for releasing heat generated in the collector 3 projecting from the satellite panel 1 serving as the outer wall of the satellite to the outside of the satellite. Dissipates the generated heat directly into outer space. Further, the traveling wave tube 90 is provided with a heat shield 95, and blocks heat dissipated by the radiation fins 94 so as not to return to the inside of the satellite.

The heat dissipating fins 94 for dissipating heat are shown in FIG.
As is clear from FIG. 6 (A) and FIG. 6 (B), it is formed in a rectangular thin plate shape and is coplanar with the central axis of the collector 3 in the meridian direction of the outer periphery of the cylindrical collector 3 and 8
The sheets are arranged at equal intervals around the outside of the collector 3.

Since the use of the radiation-cooled traveling-wave tube reduces the thermal load on the satellite due to this structure, the radiation-cooled traveling-wave tube is required for a satellite requiring a high output of several hundred watts, such as a broadcasting satellite. Is suitable.

Recently, the number of traveling wave tubes mounted on the repeater of an artificial satellite has increased due to the increase in the number of channels.
The satellite launched in 1965 was equipped with two traveling-wave tubes, while the satellite launched in 1997 was equipped with three traveling-wave tubes.
Four traveling wave tubes were mounted by high-density mounting. Due to such a large number of traveling wave tubes, there is an increasing demand for a radiation cooling type even for traveling wave tubes having a small output of several tens to hundreds of watts.

However, when a large number of radiant cooling type traveling wave tubes are mounted side by side and adjacent to each other as described above, the radiation fins 94 described with reference to FIG. When the plane including the central axis of the collectors of the radiation cooling type traveling wave tubes arranged side by side is used as the mounting surface, the heat dissipating surface on the disposing surface side of the heat dissipating fins 44 is replaced by the fins 42 on the disposing surface side.
And a fin 45 of an adjacent radiation-cooled traveling wave tube facing it, a closed space is formed, and heat stays in this closed space to deteriorate the heat radiation function.

As a result, the radiation capability of each radiating fin is reduced, causing an excessive rise in temperature of the traveling wave tube. Excessive temperature rise has a significant adverse effect on the performance and reliability of the traveling wave tube, such as causing the release of occluded gas contained in the microwave tube components and causing a decrease in the degree of vacuum in the traveling wave tube. .

On the other hand, another technique for forced cooling is as follows.
For example, it is described in JP-A-58-44755. In this structure, a part of the radiation fin is divided into a bimetal structure, and only the part of the bimetal structure among the arranged radiation fins curves into the surrounding fluid for cooling in a high temperature environment, and By greatly disturbing the flow, an improvement in the heat radiation effect is realized.

However, this technology relates to heat radiation by a fluid, and since the radiation by the heat radiation surface in space where there is no fluid air is a radiation cooling type, the size and direction of the heat radiation surface with respect to space are Affect the effect.

[0018]

The above-mentioned conventional radiation-cooled traveling wave tube has the following problems.

The first problem is that when a plurality of radiant cooling type traveling wave tubes are mounted side by side and adjacent to each other, the heat radiation function is deteriorated.

The reason is that when the plane including the central axis of the collectors of the radiation cooling type traveling wave tubes arranged side by side is used as the disposition surface, the heat dissipating surface on the disposing surface side of the heat dissipating fin is different from the heat dissipating fin on the disposing surface side. This is because a closed space is formed between the radiating fins of the adjacent radiation cooling type traveling wave tubes facing each other, and heat stays in this closed space.

The second problem is that when the satellite enters the backside of the earth that does not receive sunlight, the insulation of the high voltage part may be reduced.

The reason is that when the satellite enters the back side of the earth where it does not receive sunlight, the satellite is cooled, but it is further cooled by radiation cooling type radiating fins and used for insulation of high voltage parts. This is because the temperature of the resin used is lower than the minimum allowable temperature of the insulating function.

An object of the present invention is to efficiently dissipate the heat generated by a collector in a high-temperature environment even when a plurality of radiation-cooled traveling wave tubes are mounted side by side and adjacently, while preventing overcooling in a low-temperature environment. It is an object of the present invention to provide a radiation-cooled traveling wave tube that can be used.

[0024]

A radiation-cooled traveling wave tube according to the present invention is a radiation-cooled traveling wave tube having a radiation fin for radiation cooling on the outer periphery of a collector. To face the space side, and in a low-temperature environment, so as to face at least one of the outer peripheral surface of the collector and the surface of the radiation fin of the adjacent radiation cooling type traveling wave tube,
The heat radiating fin has a heat radiating surface formed by laminating a high thermal expansion material on one surface and a low thermal expansion material on the other surface.

One specific means of the radiation cooling type traveling wave tube according to the present invention has a plurality of radiation cooling fins provided on the outer peripheral surface of a cylindrical collector in the meridian direction of the collector. In the radiation-cooled traveling wave tube, the radiation fin has any one of a plane parallel and perpendicular to an arrangement surface formed by a plurality of radiation-cooled traveling wave tubes disposed adjacent to each other. Except for the above, a heat-dissipating surface constituted by bonding a low-thermal-expansion material on a surface close to the mounting surface and a high-thermal-expansion material on a surface near a surface perpendicular to the mounting surface is provided.

Further, as another means, in a radiant cooling type traveling wave tube having radiant cooling radiating fins which form a surface perpendicular to the axial direction of the collector on the outer periphery of the collector, the radiating fins are arranged in a high temperature environment. The surface on the outer space side has a high thermal expansion material, and the surface on the satellite body side has a heat radiating surface configured by laminating a low thermal expansion material, and the heat radiating surface has a high emissivity surface on the outer space side. In addition, the effect can be increased by treating the surface of the satellite body side with the respective reflecting surfaces.

As described above, with the bimetal structure, the heat dissipating fins can be reduced in a high-temperature environment by reducing the heat retention area surrounded by the heat dissipating fins and maximizing the heat dissipating surface facing the outer space. It is possible to enlarge the heat retention area surrounded by the radiation fins and minimize the radiation surface facing the outer space.

[0028]

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

FIG. 1 is a structural explanatory view showing an embodiment of the present invention. 1 (A) and FIG.
As shown in the AA cross-sectional view in FIG. 1A of FIG. 1A, the cylindrical collector 3 of the radiation-cooled traveling wave tube 2 projecting from the satellite panel 1 into the outer space is formed by a meridian around the outside. It is assumed that the radiating fin 4 has eight radiating fins 4 having a surface in the direction and having an angle of 45 degrees with the adjacent one. Further, a flat plate of a heat shield 5 is provided between the radiation fin 4 and the satellite panel 1 perpendicularly to the center axis of the traveling wave tube 2 to block heat emitted from the radiation fin 4 toward the satellite panel 1. And Further, a plurality of traveling wave tubes 2 are arranged adjacent to each other in the horizontal direction, and form a plane as an arrangement surface.

As shown in FIG. 1B, the radiation fins 4 include fins 41 perpendicular to the installation surface, fins 42 on the installation surface, and fins 4 provided between them.
There are 3,44. Further, as shown in an enlarged view of a portion B which is a tip portion of the fin 44 in FIG. 1 (C) in FIG.
A high-thermal-expansion material 6 such as copper, stainless steel, or aluminum is used on the surface on one side, and a low-thermal-expansion material 7 such as tungsten or molybdenum is used on the surface on the fin 42 side on the disposition surface. I have.

Next, with reference to FIG. 1 and FIG. 2, the effect exerted by using such two materials having different expansion rates will be described.

In a high-temperature environment in which a satellite in an orbit around the earth is irradiated with sunlight and the surface temperature reaches approximately 200 degrees Celsius, the fins 43 and 44 extend from the high thermal expansion material 6 to the low thermal expansion material 7. The bimetal effect that exceeds elongation
As shown in FIG. 2 (A), the fin 42 approaches the surface of the fin 42 on the arrangement surface and is deformed to be substantially parallel. Therefore, the effective area of the heat radiation fins 4 in the direction perpendicular to the installation surface radiating to the outer space increases as compared with the normal temperature environment on the earth shown in FIG. Since the heat stagnation area is reduced, more heat of the collector 3 can be dissipated by radiation.

On the other hand, in a low-temperature environment in which the satellite in orbit around the earth is not irradiated with sunlight and the surface temperature reaches approximately minus 50 degrees Celsius, the fins 43 and 44 cause the shrinkage of the high thermal expansion material 6 to be low. Due to the bimetallic effect exceeding the shrinkage of the thermal expansion material 7, as shown in FIG. 2C, the fin 41 approaches the surface of the fin 41 perpendicular to the mounting surface and is deformed so as to be substantially parallel. Therefore, the effective area of the heat radiation fins 4 in the direction perpendicular to the installation surface radiating to the outer space is reduced as compared with the normal temperature environment on the earth shown in FIG. Since the heat stagnation area increases, the amount of the heat of the collector 3 escaping to the outer space decreases, so that supercooling can be prevented.

In the above description, the number of fins is eight.
Although the sheets are arranged at equal intervals, the number, position, size, and the like are arbitrary, and the above description does not limit the present invention.

Next, another embodiment different from the above description will be described with reference to FIGS. FIG.
FIG. 9A is a main configuration diagram (A), a partially enlarged view (B), and a perspective view (C) showing another embodiment different from FIG.

FIGS. 3A and 3C show a state in a high-temperature environment. A radiation-cooled traveling wave tube 2 has an outer periphery around a cylindrical collector 3 projecting from a satellite panel 1 into outer space. In addition, a radiation fin 11 which forms a plane perpendicular to the central axis of the collector 3 is provided, and a heat shield 12 having a plane parallel to the radiation fin 11 is provided between the radiation fin 11 and the satellite panel 1.

As shown in FIG. 3B in which the heat radiation fin 11 is enlarged from a portion C at the tip of the heat radiation fin 11 in FIG. On the side surface, a high thermal expansion material 13 such as copper, stainless steel, or aluminum is used.
A low thermal expansion material 14 such as tungsten or molybdenum is used on the surface of the satellite body. Therefore, FIG.
The radiation fin 11 shown in FIG.
Is greater than the low thermal expansion material 14.

Next, with reference to FIG. 3 and FIG. 4, the effect exerted by using such two materials having different expansion rates will be described.

In a high-temperature environment in which a satellite in orbit around the earth is irradiated with sunlight and the surface temperature reaches approximately 200 degrees Celsius, the heat radiation fins 11 expand the high thermal expansion material 13 and expand the low thermal expansion material 14. 3 and 4A, the surface of the radiating fin 11 is deformed so as to be substantially parallel to the surface of the heat shield 12. As shown in FIG. Therefore, as compared with the normal temperature environment on the earth shown in FIG.
Is increased, so that more heat of the collector 3 can be dissipated by radiation.

On the other hand, in a low-temperature environment in which the satellite in orbit around the earth is not irradiated with sunlight and the surface temperature reaches approximately minus 50 degrees Celsius, the heat radiation fin 11 causes the high thermal expansion material 13 to shrink with low thermal expansion. Due to the bimetallic effect exceeding the shrinkage of the material 14, the collector 14 is deformed so as to approach the outer peripheral surface of the collector 3 until it becomes substantially parallel as shown in FIG. As a result, the effective area of the radiating fins 11 with respect to the outer space opposite to the collector 3 increases as compared with the normal temperature environment on the earth shown in FIG.
The radiation amount of the radiation fins 11 to the outer peripheral surface increases.

Therefore, one side of the high thermal expansion material 13 is subjected to a surface treatment such as anodic oxidation for increasing the emissivity, and the other side of the low thermal expansion material 14 is subjected to a mirror surface treatment such as nickel plating for increasing the reflectance. In the case of application, the direction of heat dissipation is only from the surface of the high thermal expansion material 13 with increased emissivity.
The interior of the satellite is less affected by the heat of the collector 3 because it does not receive heat from the
Receives the heat of the collector 3 from the radiating fins 11 and makes it difficult for the heat of the collector 3 to escape to outer space, thereby preventing overcooling.

In the above description, only one surface perpendicular to the center axis of the collector is illustrated and the outside of the collector in the vertical direction is curved by the bimetal effect. However, other shapes such as the center axis of the collector are used. A plurality of fins may be provided on the outer periphery in a vertical plane, and in a low-temperature environment, the fins may be configured to surround the outer periphery of the collector with the plurality of fins.

[0043]

As described above, according to the present invention, the following effects can be obtained.

The first effect is that, in a high-temperature environment, a decrease in output and a decrease in the degree of vacuum in the metal cylindrical envelope are prevented, so that the operation is stabilized and the life can be extended. .

The reason for this is that the radiating fins of the collector projecting outside the satellite have a bimetal effect, and in a high-temperature environment, reduce or eliminate the area where heat stays, while reducing the effective area for radiation to outer space. Because it can be enlarged.

The second effect is that, in a low-temperature environment, the temperature of the resin used for insulating the high-voltage portion can be prevented from falling below the minimum allowable temperature for the insulating function, and the life can be extended. It is.

The reason is that the radiation fins of the collector projecting outside the satellite have a bimetal effect, and in a low-temperature environment, at least one of the radiation fins of the collector and the outer periphery radiates the heat radiated by the radiation fins of the collector. This is because it is possible to prevent supercooling by minimizing the heat that escapes to the outer space by receiving the heat.

[Brief description of the drawings]

FIG. 1 is a main configuration diagram (A), a partial cross-sectional view (B), and a partial enlarged view (C) showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an effect in FIG. 1;

FIG. 3 is a main configuration diagram (A), a partially enlarged view (B), and a perspective view (C) showing an embodiment different from FIG. 1;

FIG. 4 is an explanatory diagram of an effect in FIG. 3;

FIG. 5 is a configuration explanatory view showing an example of the related art.

FIG. 6 is a side view (A) and a partial front view (B) of a main structure showing an example of the conventional art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Satellite panel 2, 90 Traveling wave tube 3 Collector 4, 11, 94 Radiation fin 5, 12, 95 Heat shield 6, 13 High thermal expansion material 7, 14 Low thermal expansion material 41-45 Fin 91 Electron gun 92 Slow wave circuit 93 Collector electrode

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoichi Kawakami 2-12-5 Iwamotocho, Chiyoda-ku, Tokyo Research Institute for Next-Generation Satellite Communications and Broadcasting Systems Co., Ltd. (56) References JP-A-5-82030 ( JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) H01J 23/033

Claims (4)

(57) [Claims] 1. A radiation cooling type traveling wave tube having radiation cooling fins on the outer periphery of a collector, wherein the surface of the radiation fin faces the outer space side in a high temperature environment, and the outer peripheral surface of the collector in a low temperature environment. The radiation fins are formed by bonding a high thermal expansion material to one surface and a low thermal expansion material to the other surface so as to face at least one of the surfaces of the radiation fins of the adjacent radiation cooled traveling wave tube. A radiation-cooled traveling wave tube comprising a surface. 2. A radiation cooling type traveling wave tube having a plurality of radiation cooling fins provided on the outer peripheral surface of a cylindrical collector in the meridian direction of the collector, wherein the radiation fins are arranged adjacent to each other. Except for a radiation fin having a surface parallel or perpendicular to an arrangement surface formed by a plurality of radiation-cooled traveling wave tubes, a low thermal expansion material is provided on a surface close to the arrangement surface, and A radiation-cooled traveling-wave tube, comprising: a heat-dissipating surface formed by laminating a high-thermal-expansion material on a surface closer to a surface perpendicular to an arrangement surface. 3. A radiation cooling type traveling wave tube having radiation cooling fins that form a surface perpendicular to the axial direction of the collector on the outer periphery of the collector. A radiant cooling type traveling-wave tube, comprising: a heat-dissipating surface formed by laminating a high-thermal-expansion material and a low-thermal-expansion material on the surface of the satellite body. 4. A radiation-cooled traveling wave tube according to claim 3, wherein the heat radiation surface is treated to have a high emissivity surface on the outer space side and a reflective surface on the satellite body side. .