JPH01146228A - Cavity combination type travelling-wave tube - Google Patents

Abstract

PURPOSE:To release the heat generated at a drift tube efficiently by burying a cooling plate which occupys from the drift tube to the outer periphery ot a pole piece in the pole piece, with its whole side surface contacting to the pole piece, and forming the cooling plate with a material of the heat conductiv ity higher than that of the pole piece. CONSTITUTION:In each pole piece, a copper plate 60 is buried being held by the pole pieces, and the whole surface of both sides of the copper plate 60 are contacted to the pole piece plates 62. Moreover, the inner side eud of the copper plate 60 is soldered to the outer periphery of a drift tube 38, the outer side end extends to the outside of the outer periphery wall of the pole piece, and plural cooling fins are soldered to the outer side end. When the travelling- wave tube is operated, the heat generated at the drift tube 38 is delivered to the copper plate 60 which is soldered to the drift tube, and released out of the tube through the cooling fins 42 furnished at the outer periphery wall of the copper plate 60 of the pole piece efficiently. Since the copper plate 60 is contacted to the pole piece plate 62 with the whole side surface which occupies a broad area, the heat of the pole piece is also released to the outside efticiently by the cooling fins 42 through the copper plate 60.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cavity-coupled traveling wave tube using a periodic permanent magnet (P'PM) electron beam focusing device, and more particularly to a cavity-coupled traveling wave tube using a periodic permanent magnet (P'PM) electron beam focusing device. This invention relates to improvements in the cooling structure of the high frequency circuit section of a wave tube.

BACKGROUND OF THE INVENTION Currently, various traveling wave tubes are used in fields such as communications and broadcasting. A traveling wave tube consists of an electron gun that emits an electron beam, a high-frequency circuit where the electron beam from the electron gun interacts with a high-frequency signal, a collector that captures the electron beam, and a periodicity that focuses the electron beam passing through the high-frequency circuit. It basically consists of a magnetic field device, etc. As such a traveling wave tube, there is a cavity-coupled traveling wave tube having a plurality of drift tubes in a high frequency circuit.

FIG. 3 is a longitudinal sectional view of a high frequency circuit section of an air-cooled cavity-coupled traveling wave tube using a periodic permanent magnet as a periodic magnetic field device. Moreover, FIG. 4 is a sectional view taken along the line AA in FIG. 3. 3 is a sectional view taken along line BB in FIG. 4.

According to FIG. 3, a pole piece 10 having a plurality of coupling holes 14 for cavity coupling around the periphery is provided with a drift tube 18 having an electron beam passage hole 16 in the center, and the pole piece 10 and the drift tube 18 is brazed. The pole piece 10 having the drift tube in the center is alternately brazed to the cavity envelope 11 to form a cavity 12 and constitute a high frequency circuit.

Furthermore, an annular permanent magnet 2 is provided on the outer periphery of the cavity envelope 11.
The pole piece 10 cooperates with the annular permanent magnet 20 to form a focusing device that focuses the electron beam passing through the drift tube onto the center axis of the drift tube 18.

Further, during operation of such a traveling wave tube, the drift tube is heated by body current and induced current. The heat is conducted from the drift tube 18 to the pole piece 10. In order to dissipate the heat conducted to the pole piece outside the traveling wave tube, there are many cooling fins 2 on the outer periphery of the pole piece lO.
2 is brazed.

In addition to the above-mentioned cooling means using the air cooling method, as a conventional technique, there is a water cooling method in which a heat pipe is passed through the pole piece 10 along the tube axis, and heat is dissipated and cooled by cooling water flowing inside the heat pipe. is also publicly known. (See US Pat. No. 4,471,266) Problems to be Solved by the Invention In the structure as described above, the pole piece forms a high frequency circuit and also forms a magnetic circuit. Therefore, iron is generally used as the material for pole pieces. However, iron has low thermal conductivity and cannot efficiently guide the heat generated in the drift tube to the cooling fins. As a result, when the traveling wave tube is in operation, the temperature of the drift tube gradually rises, causing problems such as deterioration of electrical characteristics due to thermal expansion of the drift tube and gas release within the high frequency circuit. . Additionally, the iron pole piece itself, which is heated via the drift tube, has a low thermal conductivity and therefore cannot be cooled sufficiently.

In addition, even when using a water cooling method in which a heat pipe is passed through a pole piece along the tube axis, cooling is achieved because the heat generated by the drift tube is similarly guided to the heat pipe via the iron pole piece and dissipated. It is insufficient. Furthermore, cooling methods using heat pipes have the disadvantage that they not only have a complicated structure and make the product expensive, but are also prone to problems such as water leaks and pipe breakage due to freezing of the cooling water. .

Therefore, the present invention aims to solve the above-mentioned drawbacks and provide an air-cooled coupled cavity traveling wave tube having a structure that can efficiently dissipate the heat generated in the drift tube. be.

Means for solving the problem, that is, according to the present invention, a periodic structure in which pole pieces supporting a drift tube on the inner periphery and provided with heat dissipation means on the outer periphery and annular permanent magnets are arranged alternately. In the cavity-coupled traveling wave tube equipped with a magnetic field device, a cooling plate extending from the drift tube to the outer periphery of the pole piece is embedded in the pole piece with its entire side surface in contact with the pole piece. , the cooling plate is formed of a material having higher thermal conductivity than the pole piece.

In a preferred embodiment of the invention, the cooling plate described above is a copper plate.

In the cavity-coupled traveling wave tube according to the present invention described above, a cooling plate extending from the drift tube to the outer periphery of the pole piece is embedded in the pole piece so as to be in contact with the pole piece on its entire side surface. There is. And the cooling plate is
The pole piece is made of a material with higher thermal conductivity than the pole piece. In other words, a heat conduction path is formed extending from the drift tube to the outer periphery of the pole piece. Therefore, the heat generated in the drift tube can be efficiently transmitted and dissipated outside the tube.

Furthermore, since the cooling plate is in contact with the entire surface of the pole piece, the heat of the pole piece can also be effectively radiated.

When iron is used as the pole piece body as in the past, as described above, in a preferred embodiment of the present invention, the cooling plate is formed of, for example, steel material, which has a much better thermal conductivity than iron material. In this case, the heat generated in the drift tube can be efficiently transmitted and dissipated outside the tube via the copper plate. Furthermore, since the pole piece body is made of iron as before, its function as a magnetic circuit is not impaired.

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

FIG. 1 is a longitudinal sectional view showing one embodiment of a high frequency circuit section according to the present invention, and FIG. 2 is a sectional view taken along line AA in FIG. Note that FIG. 1 is a sectional view taken along line BB in FIG. 2.

According to FIG. 1, each pole piece consists of a pair of pole piece plates 62 with a cooling plate 60, which is a copper plate, for example, sandwiched therebetween.
It consists of As in the conventional case, the drift tube 38 has an electron beam passage hole 36 and is brazed to the center of the pole piece. The pole piece has a coupling hole 34 around the drift tube 38, and is further brazed alternately with the cavity envelope 31 at the periphery to form a cavity 30 and constitute a high frequency circuit. . Further, the pole pieces are arranged alternately with annular permanent magnets 40 provided outside the cavity envelope 31 to constitute a periodic permanent magnet type focusing device.

As shown in FIG. 1, each pole piece is embedded so that a copper plate 60 is sandwiched therebetween. In other words, copper plate 6
The entire surfaces of both sides of 0 are joined to pole piece plates 62 on both sides. Furthermore, the inner end of the copper plate 60 is connected to the drift tube 3.
The outer peripheral portion of the pole piece 8 extends to the outside of the outer peripheral wall of the pole piece, and a plurality of cooling fins 42 are brazed to the outer peripheral portion of the pole piece. The cooling fin 42
is also brazed to the outer peripheral wall of the pole piece plate.

That is, in such a structure, when the traveling wave tube operates,
The heat generated in the drift tube 38 is transmitted through the copper plate 60 brazed to the drift tube, and is efficiently dissipated outside the tube by the cooling fins 42 provided on the outside of the outer peripheral wall of the copper plate 60 of the pole piece. In addition, the copper plate 60 has, on its entire side surface,
That is, since it is in contact with the pole piece plate 62 over a wide area, the heat of the pole piece is also efficiently dissipated outside the tube by the cooling fins 42 via the copper plate 60.

In the above embodiment, the cooling fins 42 for air cooling are provided at the outer end of the cooling plate.
It may also be connected to a heat vibrator or the like for water cooling.

Effects of the Invention As is clear from the above explanation, according to the present invention, the heat of the drift tube, which is heated most by the body current and induced current, can be efficiently dissipated outside the tube during operation of the traveling wave tube. can.

Therefore, heating of the drift tube can be prevented, and deterioration of electrical characteristics due to thermal expansion of the drift tube or gas release within the high frequency circuit can be suppressed.

Therefore, according to the present invention, a cavity-coupled traveling wave tube with high output and high reliability can be realized.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing one embodiment of the high frequency circuit section of the coupled cavity traveling wave tube according to the present invention, and FIG.
FIG. 3 is a vertical cross-sectional view of a high frequency circuit section of a conventional coupled cavity traveling wave tube; FIG. 4 is a cross-sectional view taken along A-A in FIG. 3; . [Main reference numbers] l0128...Pole piece 11.31...Cavity envelope 12.30...Cavity 14.34...Joining hole 18
．． 38...Drift tube 20.40...Permanent magnet

Claims (1)

[Claims] In a cavity-coupled traveling wave tube equipped with a periodic magnetic field device in which annular permanent magnets and pole pieces supporting a drift tube on the inner periphery and provided with heat dissipation means on the outer periphery are arranged alternately, the pole In the piece, a cooling plate reaching from the drift tube to the outer periphery of the pole piece is embedded in the pole piece with its entire side surface in contact with the pole piece, and the cooling plate has a thermal conductivity higher than that of the pole piece. A cavity-coupled traveling wave tube characterized by being formed of a material with high efficiency.