JPS61206135A - Electron tube output section - Google Patents

Abstract

PURPOSE:To obtain an electron tube output section to be assembled easily with small member by employing such exhaust tube as having coaxial double cylindrical section coupled integrally with a bottomed cylindrical member to be brazed through the bottom face while providing a stepped section to be fitted with the exhaust tube around the central hole in the bottom face. CONSTITUTION:A bottomed cylindrical member 14 having coaxial double cylindri cal section is provided with a stepped section 14b to be fitted with an exhaust tube 2a at the position transiting from the bottom face to the innercircum ferential cylindrical section 14a. The exhaust tube 2a made of expensive non- oxygen copper can be shortened while at the position where the exhaust tube 2a is brazed to the bottomed cylindrical member 14, just required volume of brazing material is punched from rolled foil into washer shape then burried previously at the stepped section 14b and fused. Consequently, expensive material can be saved. Furthermore when brazing the exhaust tube 2a to the bottomed cylindrical member 14, conventional regulation of the position of the exhaust tube 2 is not required because of the stepped section 14b resulting in simplifica tion of the assembling work and jig.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an output section of an electron tube, particularly a magnetron, which facilitates the installation work of an exhaust pipe, reduces the amount of related parts used, and reduces the cost.

[Background of the invention]

FIG. 2 shows an example of the output section of a conventional magnetron.

In this figure, 1 is an antenna, 2 is an exhaust pipe, 3 is an insulating cylinder, 4 is a bottomed cylinder, 5.6 is a brazing material, and 7 is a cover. The output part of this shape is constructed by sealing a bottomed cylinder 4 to the upper end of an insulating cylinder 3 that insulates the output part from the magnetron body with a hard brazing material 5 mainly composed of silver and copper. An exhaust pipe 2 made of oxygen-free copper or the like is sealed in the center hole of the bottom surface with a hard brazing material 6 similar to the above. In addition, the cover 7 is used to protect the sealed cut portion of the exhaust pipe 2 that is cut so as to hold and support the antenna 1, and to ensure an appropriate degree of coupling with a waveguide (not shown). It is a cover over the metal part.

As is well known, in a magnetron, unnecessary harmonics are generated in addition to the desired fundamental wave, so the two dimensions of the exhaust pipe 2 that sandwich the antenna 1 are set to 1/4 of the wavelength of the harmonics whose leakage is to be prevented. It functions as a choke against these harmonics. Furthermore, as proposed in Japanese Patent Application No. 54-97265, an inexpensive iron material is used for the material of the bottomed cylindrical body 4 in order to reduce the cost. In order to cope with the increase in the coefficient of expansion of both parts to be brazed, the ends to be brazed are made thin so that they are easily deformed, and a highly reliable hermetic sealing structure is achieved. There is.

The brazing material 6 used for brazing the bottomed cylindrical body 4 and the exhaust pipe 2 is a ring-shaped hard solder wire mainly composed of silver and copper. The ring-shaped brazing filler metal 6 will be deformed and its diameter will become larger, and it will melt at a position that is a little further outward than the actual location to be brazed, so use a larger amount of brazing filler metal than is really necessary for brazing. On the other hand, the brazing filler metal 5 used at the location where the bottomed cylinder 4 and the insulating cylinder 3 are brazed is made by rolling out the filler metal into a foil and punching it into a washer shape. Because it is inserted into the brazed area,
You only need the amount you need and enough.

As mentioned above, in order to provide a tick function for the purpose of preventing radio wave leakage of unnecessary harmonics, one dimension is adjusted to a fairly high precision using an assembly jig (not shown) so that it is 1/4 wavelength of the target harmonic. However, there have been cases where the exhaust pipe 2 has not been placed in the specified position and has been brazed, resulting in a defect.

[Purpose of the invention]

An object of the present invention is to provide an electron tube output section which is easy to assemble and requires a small amount of parts by modifying the conventional structure which has caused various problems as described above.

[Summary of the invention]

In order to achieve the above object, in the present invention, the bottomed cylindrical body to which the exhaust pipe is brazed is provided with coaxial double inner and outer cylindrical parts that are integrally connected through the bottom surface, and around the center hole of the bottom surface. That is, a stepped part into which the exhaust pipe fits is provided at the transition point from the bottom surface to the inner circumferential cylindrical part, and the exhaust pipe is fitted here.
It was fixed by brazing. With this structure, it is possible to insert a washer-shaped piece punched from a foil-shaped brazing filler metal into the brazed area in advance, which allows the exhaust pipe to be made from expensive oxygen-free copper. It is possible to save money by shortening the length of the exhaust pipe, and it is also possible to save on the amount of expensive brazing material mainly composed of silver and copper used to braze the exhaust pipe and the bottomed cylindrical body. .

[Embodiments of the invention]

FIG. 1 is a diagram showing an embodiment of the present invention. The bottomed cylindrical body 14 having a coaxial double cylindrical portion is provided with a stepped portion 14b that fits into the exhaust pipe 2a at a transition point from the bottom surface to the inner circumferential cylindrical portion 14a. Note that other symbols in the figure are the same as in FIG. 2. As can be clearly seen from this figure, the exhaust pipe 2a made of expensive oxygen-free copper is shorter than the conventional exhaust pipe 2 shown in FIG. At each point, just the required amount of brazing filler metal is punched out from a rolled foil to form a washer shape, embedded in the stepped portion 14b in advance, and then melted. Materials can be saved. Furthermore, in the work of brazing and fixing the exhaust pipe 2a to the bottomed cylindrical body 14, since the stepped portion 14b is provided, there is no need to adjust the position of the exhaust pipe 2 as in the past, and the assembly work is also simplified. The assembly jig also becomes easier.

〔Effect of the invention〕

As explained above, according to the present invention, when assembling the electron tube output section, the amount of expensive materials used and the number of assembly steps are reduced, resulting in an extremely large cost reduction effect for mass-produced products such as magnetrons. It will be done.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing an example of an output section of a conventional magnetron.

Claims (1)

[Claims] An antenna for deriving the output from the cavity resonator, an exhaust pipe that holds the antenna end at the sealing cut point, and the exhaust pipe is fitted and supported around the center hole on the bottom surface, and the lower end of the outer cylinder is used for insulation from the electron tube body. In an electron tube output section consisting of a bottomed cylinder brazed to an insulating cylinder, the bottomed cylinder consists of a coaxial double inner and outer cylinder part integrally connected via the bottom surface, and the bottom center hole surrounding the bottom center hole. That is, the electron tube output section is characterized in that a stepped section into which the exhaust pipe fits is provided at the transition point from the bottom surface to the inner circumferential cylindrical section, and the exhaust pipe is fitted therein and fixed by brazing.