JP2713187B2 - Method of assembling electron gun for traveling wave tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates relates to a method of assembling a traveling wave tube for electron guns is a microwave tube, particularly electrostatic traveling-wave tube
Enabling vibration resistance strength of Koju body and the electron gun for a traveling wave tube
It relates to an assembling method .

[0002]

2. Description of the Related Art FIG. 5 shows an example of a traveling wave tube which has been used relatively frequently. The traveling wave tube 5 shown in FIG.
1 includes a high-frequency circuit 53 formed in a spiral shape, an electron gun 52 mounted coaxially with the high-frequency circuit 53, and a metal vacuum envelope (case) 51A containing these. .

FIGS. 6 and 7 show the electron gun 5 in FIG.
It is the perspective view and sectional drawing which expanded the case part of 2 partly. In the traveling wave tube 51 shown in FIG. 5, an electron beam is formed from an electron gun 52 (not shown), and a high-frequency wave introduced from an input line 56 while passing through a high-frequency circuit (helix) 53 and the electron beam Interact with each other to perform high frequency amplification. The amplified high frequency is taken out from the output line 57, and the electron beam after the interaction is captured by the collector 54. Reference numeral 55 denotes a focusing magnetic field device for collecting the electron beam at the center and stably passing the electron beam through the high-frequency circuit (helix) 53.

In the electron gun section 52, reference numerals 58,
Numerals 59, 60 and 61 indicate ceramic insulating cylinders. The ceramic insulating cylinders 58 to 61 form a vacuum envelope 51A portion of the electron gun portion 52. At both ends along the central axis, one metal electrode (anode electrode) 62,
The other electrode 64 is sealed by brazing so as to maintain vacuum tightness.

Here, reference numeral 65 denotes a Wehnelt electrode for narrowing electrons emitted from the cathode electrode 67 into a thin electron beam, and reference numeral 66 denotes a cylindrical support for supporting the Wehnelt electrode 65 via the sealing dish member 63. . Further, the amount of the electron beam is controlled by changing the potential between the anode electrode 62 and the cathode electrode 67. Further, reference numeral 71 indicates an exhaust pipe.

The inside of the traveling wave tube 51 is evacuated to a high degree of vacuum of about 10 ^-9 Torr through the exhaust pipe 71 during the manufacturing process, and then the exhaust pipe 71 is pressure-sealed. .

In order to operate the traveling wave tube 51,
A filament voltage of several V for heating the cathode electrode 67 and a potential several KV higher than the cathode potential are applied to the anode electrode 62 and the helix 53. A potential lower by several KV than the helix potential is applied to the collector 54 to reduce power consumption. Here, since the case 51A has the same potential as the helix 53, the case 51A is generally operated using the potential of the helix 53 as the ground potential. Therefore, the potentials of the cathode 67 and the collector 54 become high with respect to the case 51A. Reference numeral 7
Reference numerals 2 and 73 denote insulating members such as silicon rubber for insulating the high voltage between the electron gun 52 and the collector 54.

In the structure of this type of traveling wave tube 51, the structure in which the electrodes of the electron gun portion 52 are brazed and sealed with a plurality of ceramic insulating cylinders 58 to 61 interposed therebetween is particularly used.
It has excellent vibration resistance and vacuum tightness, and has been used relatively frequently.

On the other hand, in response to recent demands for downsizing, it is difficult to braze the electron gun section 52 for downsizing, so that downsizing is performed while maintaining vibration resistance. Was one of the important issues.

FIGS. 6 and 7 show the electron gun 5 in FIG.
2 shows a conventional support structure of Wehnelt electrode 65 inside. Here, the inner and outer diameters of the ceramic insulating cylinders 58 to 61 for miniaturizing the electron gun section 52 are kept small, and as a result, the cylindrical support 66 supporting the enclosing dish member 63 and Wehnelt electrode 65 is formed. Laser welding is used for welding. In other words, if there is a space in the weld, resistance welding in which the weld is sandwiched between tweezers is used. However, since the electron gun 52 is reduced in size and there is no space, the laser welding is performed. Welding is used. Reference numeral 74 denotes a laser welding nugget indicating a welding position by laser welding.

[0011]

However, in the joining by the laser welding, since the joining can be performed only at the end faces of the sealing plate member 63 and the cylindrical support 66, the welding strength is insufficient, and there is a problem in the vibration resistance. Was. As a countermeasure, a method of increasing the welding power by increasing the laser output can be considered, but there is a limit in increasing the laser output because the thin-walled member is melted.

A method for solving such inconvenience is disclosed in Japanese Unexamined Patent Application Publication No.
-82207. 8 and 9 show the main points.

In FIG. 8, a plurality of recesses 85, 85 are formed around the joint, and the recesses 85 are irradiated with a laser, thereby increasing the melting area of the members 81, 82 to be welded. The welding strength can be improved.

In the conventional example shown in FIG. 9, the concave portion 85 shown in FIG.
Shows an example in which is cut into a square shape.

However, in such a conventional example,
The thickness of the welding member must be large enough to provide the concave portion. Therefore, it is practically impossible to weld a thin welding member having a thickness of, for example, 0.3 mm or less. It is possible.

For this reason, the cylindrical support 66 accompanying the miniaturization.
In the laser welding of the portion, in the above-described conventional example, the joining strength is insufficient, and therefore, the laser welding portion is easily cracked by vibration or impact, and the cylindrical support 66 supporting the Wehnelt electrode is formed by the traveling wave tube. Inclining with respect to the pipe axis. When this happens,
The electron beam emitted from the cathode 67 collides with the high-frequency circuit (helix) 53 and heats the high-frequency circuit. The heating of the high frequency circuit (helix) 53
Gas generation is caused, and the degree of vacuum in the sphere inside the traveling wave tube is deteriorated due to the generation of gas, thereby causing a disadvantage that the function of the traveling wave tube is stopped. That is, there is an inconvenience that the durability is reduced due to the miniaturization.

[0017]

An object of the present invention is to provide a method for assembling an electron gun for a traveling-wave tube which can solve the disadvantages of the prior art and can effectively secure the vibration resistance and durability of the electron gun even if it is miniaturized. Is its purpose.

[0018]

According to the first aspect of the present invention, a cathode electrode for emitting electrons, a Wehnelt electrode for forming electrons emitted from the cathode electrode into a thin electron beam, An anode electrode for controlling the amount, and a sealing plate member for supporting the Wehnelt electrode with a cylindrical support and supporting the cylindrical support in a fitted state within a central cylindrical protrusion. In the electron gun, the one end face of the cylindrical support and the protruding end face of the enclosing dish are set to the same plane, and a plurality of through holes are provided on a side surface of a fitting portion between the cylindrical support and the enclosing dish. In addition, a configuration is adopted in which one end face of these cylindrical supports and the joining end faces of the plurality of through holes with the sealing plate are welded by laser welding.

According to the second aspect of the present invention, a cathode electrode for emitting electrons, a Wehnelt electrode for forming electrons emitted from the cathode electrode into a thin electron beam, and an anode electrode for controlling the amount of electrons extracted from the cathode electrode An electron gun equipped with an enclosing plate member that supports the Wehnelt electrode with a cylindrical support and that supports the cylindrical support in a fitted state within a central cylindrical protrusion. One end face of the support and the projecting end face of the enclosing dish are formed by the same end face having relatively large irregularities in a continuous state, and the cylindrical support body at each crest and each valley bottom of the same end face having the concavo-convex shape. And the sealing plate are welded by laser welding.

The third aspect of the invention adopts a configuration in which the same end face of the uneven shape is the same end face of the sinusoidal shape.

This aims to achieve the above-mentioned object.

[0022]

[Operation] A cylindrical support for supporting Wehnelt electrodes at the other end, and an enclosing plate member for supporting one end of the cylindrical support in a fitted state in a cylindrical projection formed in the center in advance. Is fixed at two locations along the center axis, unlike the case of fixing only the end face in the conventional example, which sufficiently responds to vibration from any direction. be able to.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

1 and 2, reference numeral 1 denotes a cylindrical support, and reference numeral 2 denotes an enclosing plate member. The cylindrical support 1 and the enclosing dish member 2 show an improved version of the cylindrical support 66 and the enclosing dish member 63 disclosed in FIGS.

This will be described in more detail.
Has a function of holding the Wehnelt electrode 3, which is a part of the electron gun, at the other end 1B. This cylindrical support 1
Is connected to the enclosing dish member 2 with one end thereof fitted to the center of the enclosing dish member 2. The enclosing dish member 2 is formed in a disk shape, and has a cylindrical protruding portion 2A at a central portion for fitting and supporting one end of the cylindrical support 1 described above. The surroundings of the sealing dish member 2 are supported by a ceramic insulating cylinder constituting an electron gun.

The end face 1Aa of one end of the cylindrical support 1 and the protruding end face 2Aa of the cylindrical protruding portion 2A of the enclosing dish member 2 are set to the same plane. The cylindrical support 1 and the sealing dish member 2
On the side of the fitting part of the
Is provided.

Then, one end 1 of the cylindrical support 1
The joining end faces of the plurality of through holes 10 with the enclosing dish member 2 are welded at predetermined intervals by laser welding. In the end face 1Aa of the cylindrical support 1,
It is welded to the enclosure plate member 2 at ten locations. Also,
At four surrounding through holes 10 provided on the side surface of the fitting portion between the cylindrical support 1 and the sealing plate member 2, arrows A in FIG.
A laser beam for welding is irradiated from the direction, and the irradiated portion is welded.

Laser welding can be performed even in a narrow space in which conventional tweezers for resistance welding do not enter, so that it can be effectively used for integration of members when downsizing. In this embodiment, welding is performed by irradiating a laser to the end surface joint portion of the cylindrical support 1 and the joint portion exposed on the side surface of the cylinder from the tube axis direction. Reference numeral 14 denotes a nugget formed by laser welding. The plate thickness of the cylindrical support 1 and the enclosing plate member 2 is about 0.3 [mm], and depending on the laser output, the size of the nugget 14 is approximately the same as the plate thickness of the two together (about 0.6 mmφ).

As described above, according to the present embodiment, the end portion 1Aa of the cylindrical support 1 is laser-welded to the enclosing plate member 2 in the same manner as in the conventional example. Laser welding is also performed on the four surrounding through-holes 10 provided on the side surface of the fitting portion of the enclosing plate member 2, so that the two fixing points are two places along the central axis at the four surrounding places. Unlike the case of only the end face in the conventional example, it is possible to cope with vibrations from any direction. Therefore, according to the present embodiment, even when the size of the electron gun is reduced, the vibration resistance and the durability of the electron gun can be improved more than the conventional case. Equipment The electron gun can be obtained.

Next, another embodiment will be described with reference to FIGS.

The other embodiment shown in FIGS. 3 and 4 shows an end face (one end face) 1A of one end 11A of a cylindrical support 11. FIG.
1Aa and the protruding end surface 12Aa of the cylindrical protruding portion 12A of the enclosing dish member 12 are formed with a relatively large undulating and continuous concavo-convex identical end surface 20, and each crest 21 and each valley bottom 22 of the concavo-convex identical end surface. This is characterized in that the cylindrical support 11 and the sealing dish member 12 are welded by laser welding.

In this case, in this embodiment, the concavo-convex identical end face 20 is formed of a sinusoidal concavo-convex identical end face. In this embodiment, the fixing by laser welding at the bottom of each valley of the same end surface 20 of the concavo-convex shape functions similarly to the fixing by laser welding of the four surrounding through holes in the embodiment of FIG. 1 described above. It has become. Other configurations are the same as those of the embodiment of FIG. 1 described above.

In this manner, the same operation and effect as those of the embodiment shown in FIG. 1 are provided. In addition, the fitting portion between the cylindrical support 11 and the enclosing plate member 12 is short, so that laser welding can be performed. This is effective when a through hole having a size only is not provided.

[0034]

According to the present invention as described in the foregoing, as compared with laser welding only circumferentially in conventional planar, since there is provided a laser welding points distributed in the axial direction of the tube, which
In the traveling-wave tube electron gun formed by the method described above , stress is dispersed particularly against impact and vibration in the direction perpendicular to the tube axis, and the vibration resistance is improved. As a result, the Wehnelt electrode does not incline or decenter with respect to the tube axis even when shock or vibration is applied to the traveling wave tube, so that a stable beam transmission characteristic can be obtained . An assembly method can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a joint portion between a cylindrical support for supporting Wehnelt electrodes and an enclosing plate member according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a joint between the cylindrical support and the sealing dish member disclosed in FIG. 1;

FIG. 3 is a perspective view showing a joint portion between a cylindrical support for supporting Wehnelt electrodes and an enclosing dish member according to another embodiment of the present invention.

FIG. 4 is a partial cross-sectional view showing a joint portion between the cylindrical support and the sealing dish member disclosed in FIG. 3;

FIG. 5 is a partially omitted cross-sectional view showing an example of a traveling wave tube incorporating an electron gun in a conventional example.

6 is a perspective view showing a joint portion between a cylindrical support for supporting Wehnelt electrodes and a sealing plate member in the conventional example shown in FIG. 5;

FIG. 7 is a cross-sectional view showing a joining portion between a cylindrical support and an enclosing dish member in the conventional example disclosed in FIG.

8A and 8B are explanatory views showing a joining portion between a cylindrical support for supporting a Wehnelt electrode and a supporting member in another conventional example, FIG. 8A is a cross-sectional view thereof, and FIG. (A)
FIG.

FIG. 9 is a cross-sectional view showing a modification of FIG. 8A in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical support body 1A One end 1Aa One end end face 1B Other end 2 Enclosing dish member 2A Cylindrical protrusion 2Aa Projection end face 3 Wehnelt electrode 10 Through hole 62 Anode electrode 65 Wehnelt electrode 67 Cathode electrode

Claims (3)

(57) [Claims] 1. A cathode electrode for emitting electrons, a Wehnelt electrode for forming electrons emitted from the cathode electrode into a thin electron beam, an anode electrode for controlling an amount of electrons extracted from the cathode electrode, and a Wehnelt electrode. A traveling wave comprising a cylindrical support for supporting the electrode at the other end, and a sealing plate member for fitting and supporting one end of the cylindrical support in a cylindrical projection formed in the center in advance. In the electron gun for a tube, an end face of one end of the cylindrical support and a protruding end face of a cylindrical protrusion of the enclosing dish member are set on the same plane, and a fitting portion between the cylindrical support and the enclosing dish member is provided. A plurality of through holes are provided on the peripheral side surface of the cylindrical support, and thereafter, the joining end surfaces of the end portions of the cylindrical support and the plurality of through hole portions with the sealing plate member are welded by laser welding. to <b r /> Method of assembling electron gun for traveling wave tube. 2. A cathode electrode for emitting electrons, a Wehnelt electrode for forming electrons emitted from the cathode electrode into a thin electron beam, an anode electrode for controlling an amount of electrons extracted from the cathode electrode, and a Wehnelt electrode. A traveling wave comprising a cylindrical support for supporting the electrode at the other end, and a sealing plate member for fitting and supporting one end of the cylindrical support in a cylindrical projection formed in the center in advance. In the tube electron gun, the end face of one end of the cylindrical support and the protruding end face of the cylindrical protruding portion of the enclosing dish member are aligned, and each end face is formed into the same concavo-convex end face processed into a concavo-convex shape. A method for assembling an electron gun for a traveling wave tube, comprising: welding the cylindrical support and the sealing plate member at each of the crests and valleys of the concavo-convex end surface by laser welding. 3. The method for assembling an electron gun for a traveling wave tube according to claim 2, wherein said concavo-convex identical end face is a sinusoidal concavo-convex identical end face.