JPH02247950A - Magnetron - Google Patents

Abstract

PURPOSE:To reduce a number of airtight connection parts for enhancing reliability by providing a portion where an outer lead goes through an insulating ceramic with a flange part for being vacuum-tightly sealed thereto. CONSTITUTION:Outer leads 25 and 26 are respectively connected to cathodes 31 and 32 in airtight environment and exposed to the atmosphere while penetrating through an insulating ceramic 4. Flange parts 25a and 26a are provided on respective spots where the outer leads 25 and 26 penetrate through the insulating ceramic 4 on the cathode side and are brazed so as to close holes through which the outer leads 25 and 26 penetrate. Accordingly, those parts are airtightly sealed. By means of the airtight sealing, a number of other parts to be airtightly sealed is reduced so that reliability of a magnetron is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetron, and more particularly to a magnetron with an improved lead structure for input power.

[Conventional technology]

The conventional magnetron cathode structure is disclosed in Japanese Patent Application Laid-Open No. 62-9853.
As described in Publication No. 6, in FIG. 3, cathode leads 1 and 2 and external leads 5 and 6 were connected via relay plates 7 and 7. On the other hand, in the example described in Japanese Unexamined Patent Publication No. 62-49307, in FIG.
is connected to. Note that 4 and 14 indicate insulating ceramics.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into consideration the dependability of airtight joint parts, and in the example shown in FIG.
In the example shown in FIG. 4, the insulating ceramic 14 and the external leads 15, 16 . The external leads 15 and 16 and the cathode leads 11 and 12 require airtight joints at two locations each, which causes deterioration in reliability.The purpose of the present invention is to reduce the number of airtight joint locations and improve reliability. The purpose is to provide an improved magnetron.

[Means to solve problems]

For the above purpose, one end of the rod-shaped external lead is made into a flange shape. In other words, by making the diameter of the end of the external lead larger than the diameter of the hole through which the external lead passes through the insulating ceramic, the joint surface with the insulating ceramic is established and an airtight connection is achieved.

[Effect]

Since the flange surface of the external lead is hermetically sealed to cover the external lead through hole in the insulating ceramic, the reliability of this part is greatly improved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure is a sectional view of the main part of the cathode stem portion of the magnetron.

34 is a cathode that emits thermoelectrons, 35 is an anode that forms a cavity resonator inside, and a magnetic pole 33 that concentrates lines of magnetic force from outside the tube body into the action space formed by the cathode 34 and the anode 35; 54, and a sealing metal 33.degree. 36 is brought into contact with the cylindrical portion of the anode 35 so as to encompass these. Further, the ceramic as a sealing member holds the cathode 34 and has a cathode terminal 51 supplying the cathode electrode, an insulating ceramic 4 bonded to the sealing metal 44, and an antenna 40 extending from a specific vane of the anode 35. enclosure, said sealing metal 36
and an antenna ceramic 41 which is joined to an exhaust pipe support 42 that holds an exhaust pipe 43 and serves as a radiation window for generated microwaves.

Here, the cathode structure includes a filament 34.

Upper end shield 37 that prevents thermoelectrons from deviating in the tube axis direction. It is held by the lower end shield 38.

The upper end shield 37. The lower end shield 38 includes cathode leads 31. each made of a high melting point metal such as Mo.
The brazing is fixed at 32. Here filament 3
4 is made of a thorium tungsten wire whose surface is carbonized and is therefore brittle, so a spacer 39 made of an insulator is provided for the cathode leads 31 and 32 to be inserted inside the vacuum base in order to prevent breakage due to external vibrations. ing. Here, the sealing metal 44 and the external leads 25 and 26 are brazed to the metallized surface formed on the end surface of the insulating ceramic 4,
Further, the other end of the sealing metal 44 is hermetically welded to the anode 35. At this time, insulating ceramic 4 and external leads 25 and 26
The brazing is performed so that the flanges 25a and 28a formed on the external leads 25 and 26 block the holes through which the insulating ceramic external leads 25L26 pass. On the other hand, two cathode leads 31 and 32 are respectively fixed to the inner end surfaces of the external leads 25 and 26 inside the vacuum container to supply power to and support the filament. Here external lead 2
5.26 is formed with a recessed hole for positioning when the cathode lead 31.32 is fixed.

According to this embodiment, it is possible to reduce the number of hermetically sealed parts when constructing the vacuum container of the magnetron. Moreover, the third
Compared to the conventional example shown in FIGS. 4 and 4, the hermetic sealing structure of the main parts is simplified, so that a high degree of component accuracy and assembly accuracy are no longer strictly required.

〔Effect of the invention〕

According to the present invention, a highly reliable magnetron can be obtained since the number of hermetically sealed parts can be reduced.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of essential parts of one embodiment of the present invention, and FIG.
The main part perspective view, FIG. 3, and FIG. 4 are a perspective view and a sectional view of a conventional example, respectively. 31.32... Cathode lead, 4... Insulating ceramic, 25.26... External lead, 25a, 26a.
...Flange part, 44...Sealing metal. Fig. 1 4... Insulating ceramic 44... Seal S metal Fig. 4: Thread colored edge ceramic 1. ．． Figure 7: CP Hide 1 board

Claims (1)

[Claims] 1. Two cathode leads holding two end shields fixed to the upper and lower ends of a filament that emits thermionic electrons are arranged inside the vacuum of an insulating ceramic forming part of a vacuum envelope, and the insulating In a magnetron, two external leads that can penetrate the ceramic and lead out to the outside of the vacuum are electrically connected to the cathode lead, and the cathode lead side end of the external lead has a flange that is vacuum-tightly sealed to the insulating ceramic. A magnetron characterized by having a section.