JPH04237924A - Manufacture of helix type traveling wave tube - Google Patents

Abstract

PURPOSE:To enable easy welding operation to connect high frequency input/ output part and an edge of helix and to improve reliability without deteriorating characteristics, by providing a lazer beam penetration hole at an envelope. CONSTITUTION:A lazer beam penetrating hole 10 is provided-outside a wall of an envelope/beforehand and can easily irradiated an inner conductor of a coaxial line 2 and a welding part 8 of a helix side from outside with a lazer beam 9. From the hole 10, the lazer beam is radiated on the welding part 8 for the lazer welding of it. After that the hole 10 is sealed vacuum tight, and the envelope 1 returns to its original condition. After process forming of the hole 10, burrs formed on inner diameter of the envelope 10 when honing processing, can be removed. Thus, when a travelling wave tube toward high frequency band is with a small opening 7, or when distance from the opening 7 to the welding part 8 is long, welding work, to connect the high frequency in/out part and helix side can easily be operated, which can obtain high reliability.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a helical traveling wave tube, and more particularly to a method for welding an inner conductor of a coaxial line of a high frequency input/output section to an end of the helix.

0002

2. Description of the Related Art In a helix-type traveling wave tube, the high frequency input/output section usually consists of a coaxial line, and a laser welding method is used to weld the inner conductor of this coaxial line to the end of the helix. FIG. 2 is an explanatory diagram showing the laser beam irradiation method and internal structure used when welding the inner conductor of the coaxial line and the end of the helix in the high frequency input/output section of a conventional helix type traveling wave tube. 1 is the envelope, 2 is the coaxial line, 3 and 4 are the outer conductor and inner conductor of the coaxial line 2, respectively, 5 is the helix,
6 is a support rod, 7 is an opening of the envelope 1, 8 is a welded portion between the inner conductor 4 and the end of the helix 5, and 9 is a laser beam.

Conventionally, in order to weld the inner conductor 4 of the coaxial line 2 to the end of the helix 5, a method has been adopted in which a laser beam 9 is irradiated from the opening 7 to the welding part 8.

0004

[Problems to be Solved by the Invention] In order to weld the inner conductor of the coaxial line of the high frequency input/output section and the end of the helix, which has been adopted in the production of conventional helix-type traveling wave tubes, a laser beam is used to weld the end of the helix. In the method of irradiating the welding part from the opening of the
If the distance from the opening to the welding part is long, there is a problem in that welding is difficult.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a method that is easy to work with and can obtain highly reliable welding.

[0006]

[Means for Solving the Problems] The method of the present invention is such that a laser beam can be easily irradiated onto the welded portion of the inner conductor of the coaxial line of the high frequency input/output section and the end of the helix from the outside of the envelope in advance. A transmission hole is provided, and laser welding is performed by irradiating a laser beam from the transmission hole. After welding, the laser beam transmission hole is vacuum-tightly sealed.

[0007]

[Effect] According to the above method, regardless of the size of the opening or the distance from the opening to the welding area, it becomes easy to irradiate the welding area with the laser beam, and highly reliable welding can be obtained. .

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a laser beam irradiation method for welding the inner conductor of a coaxial line and the end of a helix in a high frequency input/output section of a helical traveling wave tube according to the present invention. In the figure, 1, 2, 7, 8, and 9 are the same as or correspond to the same reference numerals in FIG. 2, and 10 is a laser beam transmission hole provided in the envelope 1.

A laser beam transmission hole 1 is provided in advance in the side wall of the envelope 1 through which a laser beam 9 can be easily irradiated from the outside onto the welded portion 8 of the inner conductor 4 of the coaxial line 2 and the end of the helix 5.
0 is provided, and a laser beam is irradiated onto the welding portion 8 through this transmission hole 10 to perform laser welding on the welding portion 8.

After welding, the laser beam transmission hole 10
are vacuum-tightly sealed, and the envelope 1 is returned to its original state. Incidentally, by honing the inner diameter of the envelope 1 after processing and forming the transmission hole 10, the burrs created during the processing of the transmission hole 10 can be removed.

[0011]

[Effects of the Invention] As explained above, according to the present invention,
Even in the case of traveling wave tubes in the high frequency range with small openings or the distance from the opening to the welding part being long, welding work to connect the high frequency input/output part and the end of the helix can be easily carried out, improving reliability. You can get something expensive.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a laser beam irradiation method when welding an inner conductor of a coaxial line of a high-frequency input/output section of a helix type traveling wave tube and an end of a helix.

FIG. 2 is an explanatory diagram showing a laser beam irradiation method used when welding an inner conductor of a coaxial line and an end of a helix in a high-frequency input/output section of a conventional helix-type traveling wave tube.

[Explanation of symbols]

1 Envelope 2 Coaxial line 3 Outer conductor 4 Inner conductor 5 Helix 6 Support rod 7 Opening 8 Welded part 9 Laser beam 10 Laser beam transmission hole

Claims (1)

[Claims] Claim 1. A method for manufacturing a helix-type traveling wave tube in which the slow wave circuit consists of a helix and the high frequency input/output section consists of a coaxial line, the inner conductor of the coaxial line of the high frequency input/output section and the end of the helix being welded. 1. A method for manufacturing a helix-type traveling wave tube, which comprises irradiating a laser beam through a laser beam transmission hole provided in a helix envelope, and sealing the laser beam transmission hole vacuum-tight after welding.