JPS62115627A - Manufacture of magnetron - Google Patents

Abstract

PURPOSE:To facilitate the welding work while improving the welding performance so as to eliminate a crack or a pin hole completely, by extending the projecting part of an anode terminal section longer than the projecting part of a sealing member, then securing it by welding. CONSTITUTION:An end section 1a of an anode cylinder 1 made of copper is formed while being projected further than the end section of a magnetic pole 9 then vacuum sealed through arc welding. Consequently, the copper material of the anode cylinder is vacuum sealed in such shape as sealed through brazing. As a result, generation of defective welding, crack or pin hole is eliminated resulting in a highly reliable magnetron.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for manufacturing a magnetron.

In general, magnetrons are widely used for heating or defrosting foods by being attached to microwave ovens or defrosting machines because they efficiently generate high-frequency output.

FIG. 1 is a cross-sectional view showing an example of a conventional magnetron. In the figure, 1 is an anode cylinder made of oxygen-free copper, for example, and has a plurality of radially divided anodes on its inner surface. A vane 2 forming a resonant cavity is provided, and the anode cylinder 1 and the vane 2 constitute an anode 3. A working space 4 formed by the tips of a plurality of vanes 2 is formed on the central axis of the anode 3, and within this working space 4, a thermoelectron emitter formed of, for example, thorium tungsten or the like in a spiral shape is formed. A cathode 5 is arranged. In this case, a working space 4 with a predetermined distance is formed between the thermionic emission cathode 5 and the tip of the vane 2 . Further, 6 and 7 are end shields arranged at both ends of the thermionic emission cathode 5, respectively, to prevent electrons from deviating in the direction of the central axis. Further, side sabots h8a, 8b and a center support 8c are fixed to the bottom surface of the end shield 7, respectively, to fixedly support the thermionic emission cathode 5 and supply operating current. The other end sides of these side supports 8a, 8b and center support 8c extend outward. Cone-shaped magnetic poles 9 and 10 are fixedly arranged at both ends of the anode cylinder 1, respectively, and form a magnetic path that converges a uniform magnetic flux within the working space 4.

Further, vacuum sealing members 11 and 12 made of, for example, iron are provided on the screen sides of the cone-shaped magnetic poles 9 and 10, respectively, for vacuum sealing the inside of the anode cylinder 1. Alternatively, they are fixed to the end of the anode 1 by arc welding, and cylindrical permanent magnets 13 and 14 are arranged on the outer surface of the vacuum sealing members 11 and 12, respectively. Further, an arm-shaped choke 15 for preventing noise leakage is fixed to the inner surface of the vacuum sealing member 11, and an output side insulator 16 formed in a cylindrical shape made of ceramic or the like is fixed to the outer surface of the choke. It is connected. At the tip of this output side insulator 16, an exhaust pipe 17 made of a copper pipe is provided.
is fixed, and this exhaust pipe 17 is hermetically pressure-welded to an antenna conducting wire 18 connected to one end of the vane 2. Further, the outer surface of the exhaust pipe 17 is covered with a metal cover 19, which protects the press-contact portion of the exhaust pipe 17, prevents sparks due to electric field concentration, and functions as a high-frequency antenna. It will be taken outside. Further, a plurality of aluminum heat sinks 20 extending in the tube diameter direction are fitted and arranged on the outer peripheral surface of the anode cylinder 1.
The outer peripheral surfaces of the permanent magnets 13 and 14 are covered by a yoke 21 for forming a magnetic path. Furthermore, permanent magnet 1
A gasket 22 formed of metal mesh or the like to prevent radio wave leakage is disposed on the outer surface of the gasket 2.
2 is held and fixed between the end of the yoke 21 and the outer peripheral surface of the vacuum sealing member 11 by a gasket receiver 23 for preventing falling off.

In the magnetron configured in this way, a side support 8a which also serves as a lead wire is connected to an external terminal (not shown).
When an input is supplied between the anode 8b and the center support 80, the thermionic emission cathode 5 is heated, and when a predetermined voltage is supplied to the anode 3, thermionic emission cathode 5 emits thermoelectrons. These thermoelectrons act within the magnetic field of the magnetic poles 9 and 1o to generate high frequency oscillation, and this output is radiated through the antenna conductor 18 into the oven of a microwave oven, for example.

Now, FIGS. 2(a) and 2(b) are diagrams showing the sealed part between the anode cylinder and the magnetic pole of the magnetron. For example, the magnetic poles 9 and 10 made of iron material are arranged at the end of the anode cylinder 1 made of steel material,
This is an example of a conventional magnetron having a joining structure in which the outer peripheral end of the magnetron is joined to vacuum-seal the inside of the anode cylinder 1.
1.12 is a vacuum sealing member made of iron material.

According to such a joint structure, in order to vacuum seal the inside of the anode cylinder 1, when the joint part is welded by arc welding, an alloy is formed with only steel and iron materials. As shown by symbol A in (c), only the very thin part at the tip of the copper and iron is welded. For this reason, pinholes or cranks are likely to occur in this welded part, and depending on welding defects, the anode cylinder 1
It has disadvantages such as the inability to keep the inside vacuum-tight.

In contrast, in the present invention, as shown in FIGS. 3(a) and 3(b), the end 1a of the anode cylinder 1 made of steel is connected to the magnetic pole 9.1.
It is formed to protrude larger than the end of the 0, and is vacuum sealed by arc welding.

According to such a configuration, the steel material of the anode cylinder is vacuum-sealed in a shape similar to that of soldering, as shown in FIGS. 4(a) and 4(b), respectively. Become.

Therefore, the aforementioned welding defects, cracks, and pinholes are eliminated, and a reliable magnetron can be obtained.

As explained above, according to the magnetron manufacturing method according to the present invention, welding work becomes extremely easy, welding performance is greatly improved, there are no cracks or pinholes in the welded part, and quality and reliability are improved. can be significantly improved. Furthermore, extremely excellent effects such as significantly lower production costs and parts unit prices can be obtained.

[Brief explanation of drawings]

Figure 1 is a sectional view of the main parts of an example of a conventional magnetron.
Figures 2(a), (b), and (C) are cross-sectional views of main parts showing an example of a conventional magnetron, and Figures 3(a), (b), and 4(a) and (b) are main part sectional views of a conventional magnetron. FIG. 1 is a sectional view of a main part of an example of a magnetron according to the invention. DESCRIPTION OF SYMBOLS 1... Anode cylinder, 3... Anode, 9, 10... Magnetic pole, 11, 12... Vacuum sealing member, 13° 14... Permanent magnet, 21... Yoke, 22...・Gasket, 2
3...Gasket receiver. To 4 Agent Patent Attorney ± 4゛ Katsuo Kawa (%',. Figure 1 Procedural Amendment (Method) September 22, 1985

Claims (1)

[Claims] 1. A method for manufacturing a magnetron in which a sealing member for maintaining a vacuum inside the anode cylinder is welded and fixed to both ends of an anode cylinder, wherein the protrusion of the anode end is fixed to the protrusion of the sealing member. A method for manufacturing a magnetron, which is characterized by making the magnetron protrude longer than before and fixing it by welding.