JPS63131439A - Manufacture of helix type traveling-wave tube - Google Patents

Abstract

PURPOSE:To obtain a slow-wave circuit being in contact with an insulating support bar at a wide surface and having a good heat capacity by winding a helix lengthy conductor having a rectangular cross section tapered at the predetermined angle on one face so that the tapered face is faced to the outside. CONSTITUTION:First, a helix lengthy conductor 21 made of a high-melting point metal such as molybdenum is prepared. This conductor 21 bas a rectangular cross section tapered at the predetermined angle theta in the lengthy direction and on a face 21a opposite to one face O. This conductor 21 is wound on a core metal 22 having the predetermined diameter. In this case, the conductor 21 is wound in the direction that the tangential line of this tapered face 21a intersects the reference face O, with the tapered face 21a faced to the outside. Thereby, the conductor 21 is set parallel or nearly parallel with a helical axis C with the tapered face 21a made the outer face of the helix while generating torsion. This outer periphery is brought into contact with an insulating support bar 23, and the contact face is soldered as required. Accordingly, a slow-wave circuit made of the helix conductor 21 having a practically wide width along an electron beam path can be obtained.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a traveling wave tube for oscillating or amplifying microwaves, and particularly to a method for manufacturing a helix of a helix type slow wave circuit. Regarding.

(Prior Art) As is well known, a helical traveling wave tube has a structure in which a helical conductor constituting a slow wave circuit is arranged around an electron beam path, allowing the electron beam to interact with a high frequency wave. This helical conductor is generally made by winding, for example, a molybdenum wire having a circular cross section in a helical manner at a predetermined pitch, or by winding a ribbon-shaped conductor having a rectangular cross section. In particular, the latter slow-wave circuit structure using a helical conductor with a rectangular cross section consists of three ceramic insulating support rods, 12.12. A ribbon-shaped helix conductor 13 is sandwiched inside the . In a slow wave circuit using such a helix conductor, the width of the helix conductor along the beam path can be widened and the thickness in the radiation direction can be made thin, so the coupling efficiency of the high single frequency electric field and the electron beam is high. The contact area between the insulating support rod and the insulating support rod can be made relatively large, resulting in excellent heat dissipation.

However, especially in a traveling wave tube that operates in a frequency band of 1o2 or more, the helical diameter of the helical conductor is small and the helical pitch is also small.

As shown in FIG. 7, this helical conductor has a rectangular cross section.
3a is wound at a predetermined pitch.

Then, the wound helix is twisted at an angle θ with respect to the helical axis C, as shown in FIG. Therefore, the inner and outer surfaces of the helical conductor 13 are oblique to the helical axis C. The angle of this twist becomes larger where the pitch interval is wider than where the helical pitch is smaller.

(Problems to be Solved by the Invention) When a helical conductor having a rectangular cross-section is wound in a helical manner as described above, the occurrence of twisting is unavoidable.

If the outer periphery of the helical conductor is supported by an insulating support rod, it will come into contact with the support rod only at the outermost point 13b of the outer surface of the helical conductor, resulting in extremely insufficient mechanical and thermal contact. For this reason, it is difficult to maintain a stable helix pitch, and there are disadvantages in that sufficient heat dissipation performance cannot be obtained.

The present invention solves the above-mentioned disadvantages and provides a helix conductor in which the outer surface of the helical conductor is parallel to the helical axis and contacts the insulating support rod over a wide area, thereby providing good heat dissipation and high mechanical support strength. An object of the present invention is to provide a method for manufacturing a traveling wave tube having a shaped slow wave circuit.

[Structure of the Invention (Means for Solving Problems) This invention provides a process for manufacturing a helix that interacts with an electron beam at high frequencies. This is a method for manufacturing a traveling wave tube in which a length conductor is wound with its tapered surface facing outward.

(Function) According to the present invention, due to the twist caused by the winding of the helical conductor, the tapered surface formed on the elongated conductor becomes parallel or almost parallel to the helical axis and is located on the outer surface of the helix. Therefore, it is possible to increase the mechanical and thermal contact area between the outer surface parallel to the axis of the helix and the insulating support rod that comes into contact with the outer surface. In this way, a traveling wave tube with excellent characteristics can be manufactured.

(Example) An example will be described below with reference to the drawings. Identical parts are designated by the same reference numerals.

FIG. 1 shows the completed state of the helix type slow wave circuit of this embodiment. First, a long helix conductor 21 made of a melting point metal such as molybdenum is prepared as shown in FIG. This elongated helix conductor 21 has an angular cross-sectional shape in which a surface 21a opposite to the longitudinal direction of the conductor and one surface 0 is a tapered surface forming a predetermined angle θ.

Then, this long helix conductor 21 is wound around a core bar 22 of a predetermined diameter, as shown in FIG. In that case, the tapered surface 21a of the conductor 21 is placed on the outside, and the conductor 21 is wound in the direction in which the tangent to this tapered surface intersects with the reference plane 0.

As a result, the helix conductor is twisted while its tapered surface 21g becomes the outer surface of the helix and becomes parallel or nearly parallel to the helical axis C, as shown in FIG.

This outer peripheral surface is brought into contact with a ceramic support rod 23 for supporting the helix, and the contact surfaces are brazed if necessary.

In this way, a slow wave circuit consisting of a helical conductor that is substantially wide in the direction along the electron beam path is created.

In the embodiment shown in FIGS. 4 and 5, the long helix conductor 21 has a parallelogram in cross section. Then, it is wound in the same manner as shown in FIG. 3 to obtain a helical slow wave circuit structure whose outer surface is parallel to the helical axis C.

[Effects of the Invention] As explained above, according to the present invention, due to the twist caused by winding the helical conductor, the outer surface becomes parallel or almost parallel to the helical axis, making contact with the insulating support rod over a wide area. is obtained. In this way, a helical slow wave circuit with good thermal conductivity (high mechanical support strength) can be obtained. Therefore, a traveling wave tube with excellent operating characteristics can be manufactured.

[Brief explanation of the drawing]

Figure 1 is a vertical sectional view of the main part showing one embodiment of the present invention,
The figure is a perspective view showing the material, FIG. 3 is a perspective view showing the manufacturing process, FIGS. 4 and 5 are perspective views and vertical sectional views of main parts showing other embodiments of the present invention, and FIG. 7 is a perspective view showing a main part of the conventional structure, FIG. 7 is a perspective view showing the state at the time of manufacture, and FIG. 8 is a sectional view of the helix. 21... Long conductor for helix, 21a... Tapered surface, 22... Core metal, 23... Insulating support rod. C...
spiral axis. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 7

Claims (1)

[Claims] In a method for manufacturing a traveling wave tube having a helix-shaped slow-wave circuit that interacts with an electron beam at high frequency, the step of manufacturing the helix includes forming a long conductor for the helix with a rectangular cross section and at least one side tapered at a predetermined angle. . A method of manufacturing a traveling wave tube, comprising winding the tube so that the tapered surface faces outward.