JPS6327417Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a traveling wave tube device using a periodic magnetic field device for electron beam focusing. Relatively long slow wave circuits (high frequency circuits) such as traveling wave tube devices
In an electron tube that allows an electron beam to pass through the interior of the tube, a periodic magnetic field device is generally used as one means for focusing the electron beam. FIG. 1 is a sectional view showing an example of a conventional periodic magnetic field device used in a traveling wave tube device. A conventional traveling wave tube device will be explained below with reference to FIG. The tube 1 includes an electron gun 11 that emits an electron beam, a slow wave circuit 12 that makes the electron beam interact with a high frequency, and a collector 13 that captures the electron beam. It is housed inside a tubular outer circumferential tube body 14 forming a section. The periodic magnetic field device 2 has a cylindrical shape as a whole, and has an outer circumferential tube body 14.
are arranged coaxially along the axis of. The periodic magnetic field device 2 is composed of a plurality of permanent magnets 21 magnetized in the axial direction and an annular magnetic pole piece 22 interposed between the permanent magnets 21, and has a periodicity for focusing an electron beam on the axis. Generates a magnetic field. As shown in FIG. 2, the permanent magnet 21 has a cylindrical shape and includes a pair of semicircular permanent magnets 24 and 25.

Generally, when it is desired to increase the allowable power of the collector 13 or when it is desired to lower the voltage of the collector 13 than the voltage of the slow wave circuit in order to improve the overall efficiency of the traveling wave tube device, the outer diameter of the collector 13 is It is larger than the outer diameter. For this reason, the required number of annular magnetic pole pieces 22 are inserted in advance along the outer periphery of the outer tube 14 before the collector 13 is attached during the manufacturing process of assembling the tube 1, and the evacuation of the tube 1 is completed. After that, a pair of permanent magnets 21 consisting of permanent magnets 24 and 25 divided into semicircular shapes are respectively interposed between magnetic pole pieces 22, and a periodic magnetic field device 2 is arranged on the outer circumferential tube body 14. . However, such a structure has the following drawbacks. That is, in order to achieve good electron beam focusing and to stably fix the periodic magnetic field device 2 on the axis of the outer circumferential tube 14, the total length of the outer circumferential tube 14 that houses the slow wave circuit 12 and the total length of the periodic magnetic field device 2 must be made equal to However, since the periodic magnetic field device 2 is formed of a large number of permanent magnets 21 and magnetic pole pieces 22, the overall length of the periodic magnetic field device 2 varies within a certain dimension. On the other hand, when the outer circumferential tube 14 of the bulb 1 is long, it is difficult to make it from a single long and thin metal tube. The total length of the body 14 also tends to vary, making it difficult to match the total length of the outer circumferential tube body 14 with the total length of the periodic magnetic field device 2. Therefore, in the manufacturing process of combining the permanent magnet 21 with the tube 1, the thickness A method is used to adjust the total length of the periodic magnetic field device 2 by separately preparing several types of permanent magnets 21 with different sizes, but this requires preparing permanent magnets 21 for size adjustment in advance, which is uneconomical and permanent. Permanent magnet 21 for adjusting the size of the magnet 21
The magnetic field strength of the converted part may change.
It was difficult to obtain the required magnetic field strength. Furthermore, if the total length of the periodic magnetic field device 2 becomes slightly shorter than the total length of the outer circumferential tube 14, the periodic magnetic field device 2 may shift in the axial direction on the outer circumferential tube 14, or the permanent magnet 2
1. It is difficult to obtain good electron beam focusing due to the rotation of the magnetic pole piece 22. As a result, the current transmittance of the tube deteriorates, the slow wave circuit 12 is burnt out, and the life of the tube 1 is adversely affected. There was a drawback that caused

The purpose of the present invention is to eliminate the above-mentioned drawbacks of conventional devices with a simple structure, and to make it possible to adjust minute axial positions of the periodic magnetic field device and the tube without replacing the permanent magnets. An object of the present invention is to provide a traveling wave tube device that can prevent directional positional deviation and stably maintain electron beam focusing of a tube for a long period of time.

Hereinafter, an embodiment of the present invention will be explained based on FIGS. 3 and 4. The tube 1 includes an electron gun section 11, a slow wave circuit 12, and a collector 13 in an outer peripheral container, just like the conventional type. The periodic magnetic field device 2 includes a plurality of permanent magnets 21 including permanent magnet pieces 24 and 25 divided into semicircular shapes, an annular magnetic pole piece 22 having an inner diameter smaller than the inner diameter of the permanent magnets 21, and an electron gun 11 side. The periodic magnetic field device 2 is composed of an annular magnetic pole piece 26 disposed at the end on the collector 13 side.
The total length of the tube is designed in advance to be slightly shorter than the total length of the outer circumferential tube body 14. The outer diameter of the annular magnetic pole piece 26 is larger than the outer diameter of the permanent magnet 21, and is divided into two parts at the extended portion 23 to form a thread. That is, the magnetic pole disc 27 and the magnetic pole cylinder 28, which are divided into two, are assembled with a screw to form an annular magnetic pole piece 26. The required number of annular magnetic pole pieces 22 and 26 are inserted along the outer periphery of the outer circumferential tube 14 during the manufacturing process for assembling the bulb 1, and the inner circumferential portion of the annular magnetic pole piece 26 is inserted into the outer circumferential end of the outer circumferential tube 14. After completing the evacuation work of the tube, a pair of permanent magnet pieces 24 and 25 divided into semicircular shapes are placed between the annular magnetic pole pieces 22 and 26 and between the annular magnetic pole pieces 22. The permanent magnets 21 are arranged so that the same magnetic poles face each other. When fixing the inner circumferential portion of the annular magnetic pole piece 26 to the outer circumferential end of the outer circumferential tube body 14 with a solid material (not shown) such as epoxy resin, the adhesive material has low heat resistance, so the tube will be heated at high temperatures. After the evacuation of the ball 1 is completed, the magnetic pole cylinder 28 forming a part of the annular magnetic pole piece 26 may be fixed. Periodic magnetic field device 2
Fine dimensional adjustment in the axial direction of the part where the permanent magnet 21 and the annular magnetic pole piece 22 are stacked can be made by rotating the magnetic pole disk 27, and the periodic magnetic field device 2 can be firmly held and fixed on the outer circumferential tube body. I can do it. That is, the annular magnetic pole piece 22 and the permanent magnet 21 can be held and fixed so that they do not move. For example, collector 13
Taking the side as an example, when the magnetic pole disk 27 is rotated, since the magnetic pole cylinder 28 is fixed to the outer peripheral end of the outer tube 14, the magnetic pole disk 27 rotates along the threaded portion.
If the permanent magnet 2 is moved and the magnetic pole disk 27 is rotated in the direction away from the collector 13 side, the permanent magnet 2
1 and the annular magnetic pole piece 22 are strongly tightened in the axial direction and are firmly held. When the total axial length of the periodic magnetic field focusing device 2 is approximately 30 cm, the minute dimension adjustment range can be adjusted.
It is practical to set the thickness to 0.5 mm to 1 mm. Since the outer diameter of the magnetic pole disk 27 is larger than the outer diameter of the permanent magnet 1, the outer periphery of the magnetic pole disk 27 can be grasped by hand and rotated easily.

However, with this structure, the permanent magnet 21
It is possible to make minute dimensional adjustments in the axial direction of the periodic magnetic field focusing device 2 without replacing the magnetic field focusing device 2, and there is no need to separately prepare permanent magnets 21 with different thicknesses, which is economical and allows the magnetic field of the periodic magnetic field focusing device 2 to be adjusted in advance. distribution can be given on the tube axis. In addition, since the magnetic pole pieces 26 disposed at both ends of the outer circumferential tube 14 are firmly held by the outer circumferential tube 14 via the magnetic pole cylinders 27, no axial displacement of the periodic magnetic field device 2 occurs. A stable current transmittance of the tube can be obtained. It is of course possible to coat the outer periphery of the periodic magnetic field device 2 with resin or the like in order to more firmly hold and fix the periodic magnetic field device 2.

In this embodiment, the magnetic pole pieces 26 are arranged at both ends of the electron gun 11 side and the collector 13 side, but it is not always necessary to arrange the magnetic pole pieces 26 at both ends, and the axial dimension of the periodic magnetic field focusing device 2 can be adjusted. Although the range is halved, it is also possible to arrange the magnetic pole piece 26 only at the end on the collector 13 side.

As explained above, according to the present invention, it is possible to easily adjust the dimensions of the periodic magnetic field device and the tube in the axial direction, securely hold and fix them, maintain stable current transmittance over a long period of time, and increase the overall length. This method is highly effective when applied to high-gain traveling wave tubes in which axial dimension adjustment is difficult.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional traveling wave tube device, FIG. 2 is a perspective view of the permanent magnet shown in FIG. 1, and FIG. 3 is a longitudinal sectional view of a traveling wave tube device according to the present invention. FIG. 4 is an enlarged vertical cross-sectional view of FIG. 3, with some parts missing. 1...Tube, 2...Periodic magnetic field device, 11...Electron gun, 12...Slow wave circuit, 13...Collector, 1
4... Outer circumferential tube body, 21... Annular permanent magnet, 22,
26...Magnetic pole piece, 23...Extended portion protruding in the axial direction on the inner periphery of the magnetic pole pieces 22, 26, 24, 25...
Permanent magnet pieces 27, 28 are formed by dividing the cylindrical permanent magnet 21 into semicircular shapes; a magnetic pole disk and a magnetic pole cylinder are formed by dividing the magnetic pole piece 26 in the radial direction.

Claims (1)

[Scope of utility model registration request] A tube 1 including an electron gun 11, a slow wave circuit 12, a collector 13, and an elongated outer circumferential tube 14 surrounding the slow wave circuit portion, and a plurality of axially arranged tubes coaxially located outside the outer circumferential tube 14. The electron gun 1 is equipped with a periodic magnetic field device 2 in which permanent magnets 21 magnetized to
The annular magnetic pole piece 26 at the end on the 1 side and the collector 13 side is connected to the magnetic pole cylinder 28 and the permanent magnet 21 fixed on both ends of the outer circumferential tube body 14 by brazing or adhesive.
The magnetic pole cylinder 28 and the magnetic pole disk 27 are assembled by screwing together, and the magnetic pole disk 27 has a magnetic pole cylinder 28 having a thread formed on its outer periphery. A traveling wave tube device characterized by being able to move upward.