JPS6032302B2 - How to manufacture a magnetron - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a magnetron, and more particularly to an improvement in a method for manufacturing a magnetron having a structure in which a permanent magnet is housed inside a ferromagnetic cylinder that also serves as a vacuum vessel.

In recent years, magnetrons for microwave ovens have generally been desired to be made smaller, and for this reason, improvements have been made to the arrangement of the magnets.

That is, magnets with good machinability based on Ee, Cr, and Co have been developed and are called spinodal magnets. This spinodal magnet has relatively good thermal conductivity,
Although the temperature coefficient of magnetic flux density is small, it is relatively expensive, so there is a demand for overall cost reduction by combining it with a magnetron manufacturing method that can be mass-produced. The present invention was made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a magnetron with good mass productivity.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the magnetron manufactured according to the present invention has an anode main body 2 tightly fixed inside a cylinder 1 made of ferromagnetic material such as Fe, which forms a part of a vacuum vessel and a magnetic path. In addition, both ends of the ferromagnetic cylinder 1 are hermetically sealed with sealing bodies 3 and 4 made of a ferromagnetic material such as Fe, and the inside thereof is a vacuum region. In other words, ferromagnetic cylinder 1
A vacuum container is formed by the sealed bodies 3 and 4. A through hole is bored in each of the sealed bodies 3 and 4, and a cathode stem 5 and an exhaust pipe 6 made of Cu are protruded so as to cover the through hole. Further, a plurality of radiator fins (not shown) are fixed to the outer periphery of the ferromagnetic cylinder 1. Further, an output portion 7 is provided to protrude from the ferromagnetic cylinder 1 in the lateral direction. The anode main body 2 is made of a cylindrical anode body 8 made of a non-magnetic material such as Cu.
A plurality of anode vanes 9 made of Cu and Th-W
A cathode body 10 is arranged. In this case, the length of the cylindrical anode body 8 and the width of the anode vane 9 are set to be the same. Furthermore, every other anode vane 9 is connected by two pairs of upper and lower strap rings 11, and an antenna conductor 12 made of Cu is fixed to one of the anode vanes 9, and this antenna conductor 12 is made of a ferromagnetic cylinder. 1 and is located within the output section 7. Further, an electron action space 13 is formed between the anode vane 9 and the cathode body 10, and a pair of permanent magnets 14,
15 is disposed coaxially with the cylindrical anode body 8, and each large opening at one end is closely fixed to the inner wall surface of the sealing bodies 3 and 4 by projection welding. In this case, each of the permanent magnets 14 and 15 is a spinodal magnet deep-drawn into a cup shape, and a ring-shaped bent portion 21 is formed at the large closed end, and a ring-shaped bent portion 21 is formed at the inner center. It has a through hole 16 and is arranged so that the through hole 16 is on the electron action space 13 side. Both ends of the cathode body 10 are fixed to an upper end hat 17 and a lower end hat 18 made of Mo, respectively, and this upper end hat 17 is made of Mo.
The lower end-hud 18 is supported by a cathode support 19 made of
is supported by two cathode supports made of Mo. The cathode supports 19 and 20 pass through the inner space of the permanent magnet 14 and the through hole of the sealing body 3, and are drawn out through the cathode stem 5 in an airtight manner. By the way, an example of the process of manufacturing the above permanent magnets 14 and 15 is shown in FIG. 2.

That is, after melting a material such as Fe, Cr, or Co, that is, a spinodal permanent magnet material, it is roughly rolled. The thickness at this time is drawn to be slightly thicker than the required final thickness, and then solution treatment and final rolling are performed. This plate material is deep drawn. This drawing process promotes ferromagnetic anisotropy in the drawing direction. If this is subjected to aging treatment and the surface dirt is cleaned by honing, permanent magnets 14 and 15 are completed. The method for manufacturing a magnetron according to the present invention is to roll a spinodal permanent magnet material in advance and then form it into a cup shape with a ring-shaped bent part integrally at one end with a large diameter by deep drawing. The ring-shaped bent portion is welded to the inner wall surface of the ferromagnetic sealed body.

Therefore, it is extremely easy to integrally mold the rig-shaped bent part for welding to the sealed body, and the magnetic contact area between the bent part and the sealed body is wide, resulting in a magnetron magnetic circuit with low magnetic loss. It is possible to create Further, there is no need to cut the magnet, and in addition to the above, the magnetron is excellent in mass production. In particular, since the permanent magnet is cup-shaped and has an integral bent part, stable welding is possible, and since the area of the welded part is large, it is easy for the heat of the magnet to escape outside the tube. Prevents the magnet from overheating. Also, because the crystals are aligned long in the longitudinal direction of the magnet due to deep drawing,
Magnetic force is enhanced. FIG. 3 shows a modification of the spinodal permanent magnet, in which an auxiliary permanent magnet 22 is press-fitted inside the permanent magnets 14 and 15. According to this, a substantially thick plate magnet can be easily manufactured.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a magnetron obtained according to the present invention, FIG. 2 is a process explanatory diagram showing an example of the magnetron manufacturing method of the invention, and FIG. 3 is a sectional view showing a modified example of a permanent magnet. 9... Anode vane, 1... Ferromagnetic cylinder, 3, 4... Sealing body, 14, 15...
- Permanent magnet, 21...Outward bending part. 3 figures, 1 figure, 2 figures

Claims (1)

[Claims] 1. A ferromagnetic sealing body is hermetically sealed to the open end of a ferromagnetic cylinder that has a plurality of anode vanes built inside and also serves as a vacuum vessel, and a cylindrical sealing body is sealed inside the ferromagnetic sealing body. In a method for manufacturing a magnetron in which an opening at one end of a permanent magnet is joined, a living-shaped outward bent part is formed at the opening at one end with a large diameter by deep drawing a spinodal permanent magnet material obtained by rolling the above-mentioned permanent magnet in advance. Form into a giblet cup shape,
A method for manufacturing a magnetron, characterized in that the outwardly bent portion of the cup-shaped spinodal permanent magnet is fixed to the inner wall surface of the ferromagnetic sealing body by welding.