JP2851860B2 - Method for manufacturing a magnetron filament support structure - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron used as a microwave oscillating device, and more particularly to a magnetron filament support structure suitable for heating equipment such as a microwave oven.

[Conventional technology]

The filament, the magnetron's thermionic emission source,
For example, it consists of a spiral of thorium-tungsten wire,
One end is connected to a center lead arranged along the axis of the spiral, and the other end is connected to a side lead arranged on the side of the spiral, so that power is supplied through the center lead and the side lead. ing.

As described in Japanese Patent Application Laid-Open No. 63-10429, for example, a filament supporting structure of this type of conventional magnetron is configured such that the filament is moved in the axial direction (magnetron) through a pair of end shields made of a refractory metal material such as tungsten. The center lead and the filament, the side lead and the filament are not directly fixed, and the other end of the side lead is particularly fixed to the lower end shield. The filament is fixed to the lower end shield at a portion different from the fixing portion.

FIG. 4 is an explanatory view of a filament supporting structure of a magnetron according to the prior art, wherein (a) is a longitudinal sectional view, (b) is a top view of a lower end shield, 1 is a filament, 1a is one end of the filament, and 1b is The other end of the filament, 2 is a center lead, 3 is a side lead, 40 is a lower end shield, 40a is a groove, 40b is a center hole, 5 is an upper end shield, and 6 is a weld.

As shown in FIG. 1A, the filament 1 is fixed at one end 1a to an upper end shield 5 to which a center lead 2 inserted through the center hole 40b of a lower end shield 40 is fixed. 1b is fixed to the lower end shield 40.

As shown in FIG. 2B, the lower end shield 40 has a ring-shaped groove 40 on the surface facing the end shield.
a is formed, and the other end of the filament 1 is welded by using the inner wall of the groove 40a as a melting white to form a welded portion 6.

The side lead 3 is fixed to the lower end shield 40, and the filament 1 and the side lead 3 are electrically connected via the lower end shield 40.

[Problems to be solved by the invention]

In the above-mentioned conventional technology, the electrical connection between the filament and the side lead is performed through two fixed portions, that is, a welded portion between the filament and the lower end shield and a connection portion between the lower end shield and the side lead. It is difficult to suppress the variation in quality in

In the known magnetron, when welding the end shield and the filament using a laser welding method, when the laser irradiation light is projected on the filament,
There is a problem of damaging the filament.

In addition, in the known magnetron, it is necessary to provide a ring-shaped groove in the lower end shield to secure a molten white for welding the end shield, which complicates the structure of the lower end shield. In addition, there is a problem that the operation of assembling the filament supporting structure cannot be simplified.

SUMMARY OF THE INVENTION The present invention solves such a problem. It is an object of the present invention to make the second end shield simple, and to perform the laser welding between the second end shield, the filament, and the side lead. It is an object of the present invention to provide a method for manufacturing a magnetron filament support structure that does not damage the magnet.

[Means for solving the problem]

In order to achieve the above object, a method for manufacturing a magnetron filament support structure according to the present invention includes a helical filament, a first end shield made of a refractory metal connected to one end of the filament, and a filament. A second high-melting-point metal connected to the other end
An end shield, a center lead passing through the axis of the helical filament and supporting the first end shield at an end, and supporting the second end shield; A method for manufacturing a magnetron filament support structure comprising a lead to be welded again, a step of pre-chamfering a surface of the side lead end opposite to a surface facing the filament, and a laser from the chamfered portion side. Means for manufacturing a filament support structure through a step of irradiating and a step of melting the chamfered portion and laser welding the other end of the filament and the end of the side lead.

In the above-mentioned means, a laser welding means is used for welding the side lead end and the other end of the filament, and the side of the side lead end opposite to the surface facing the filament is chamfered in advance, and the chamfered portion is formed. Laser irradiation is performed from the side, the chamfered portion is melted by this laser irradiation, and the other end of the filament and the side lead end are laser-welded.

That is, at the time of laser welding, laser irradiation is performed from the chamfered portion side of the side lead end, and the chamfered portion of the side lead end is easily melted by irradiating the laser beam for a short time, and the fused portion is attached to the other end of the filament. In this way, laser welding between the side lead end and the other end of the filament can be performed. At the time of this laser welding, the other end side of the filament is not directly irradiated with laser light, so that the laser welding operation can be simplified without damaging the filament,
In addition, laser welding between the side lead end and the other end of the filament can be reliably performed.

In this case, the second end shield supported by the side lead ends may be of a simple shape for preventing unnecessary diffusion of electrons, so that the manufacture of the second end shield is simplified and the manufacturing cost is reduced. Become.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of a method for manufacturing a magnetron filament support structure according to the present invention,
(A) is a longitudinal sectional view, (b) is a top view of a lower end shield, 1 is a filament, 1a is one end of the filament, 1b is the other end of the filament, 2 is a center lead, 3
Is a side lead, 4 is a lower end shield (second end shield), 4a is a side lead insertion hole, 4b is a center lead insertion hole, 5 is an upper end shield (first end shield), and 6 is a welded portion.

In FIG. 1, a filament 1 is a spiral having a wire diameter of about 0.4 to 0.6 mm and made of a material such as thorium / tungsten, and has a disk-shaped upper end shield made of a molybdenum material at one end 1a and the other end 1b. 5. The lower end shield 4 is provided.

The center lead 2 is made of molybdenum having a wire diameter of 1.0 to 2.0 mm, one end of which is fixed to an insulator (not shown) constituting a part of a magnetron vacuum vessel, and the other end of which is the center of the upper end shield 5. Into the upper end shield 5
I support.

The side lead 3 has one end fixed to the insulator constituting a part of the vacuum container of the magnetron, and the other end extending to the vicinity of the other end of the filament 1 through an insertion hole 4 a provided in the lower end shield 4. I have.

As shown in FIG. 1, the end (the other end) 3a of the side lead 3 is provided with a chamfered portion in advance on the side opposite to the surface facing the other end of the filament 1. Then, after the end of the chamfered portion is made to face the other end of the filament 1, laser light is irradiated from the chamfered portion side to melt the tip end region of the chamfered portion, and the other end of the filament 1 at the fused portion. Is welded in a form holding the wire, and laser welding is performed.

The chamfered end 3a of the side lead 3 is sharpened at an angle of about 45 degrees with respect to the axial direction of the side lead 3, and the distance between the sharp end and the point where the filament 1 is in contact is d, the line of the filament 1 About 1/2 of the diameter, in this case +0.8 to + 0.2m
m, is preferred.

According to this embodiment, it is possible to relatively easily support the filament by laser welding, and it is not necessary to provide welding lowers on the lower end shield 4, so that a simple end shield can be employed.

FIG. 2 is a sectional view of an essential part for explaining another embodiment of the present invention, in which the lower end shield 41 is formed as a ring-shaped member made of a bar.

FIG. 3 is a sectional view of a principal part for explaining still another embodiment of the present invention. In this embodiment, the lower end shield 42 is a ring-shaped body of a band-shaped material.

In the embodiment shown in FIGS. 2 and 3, the lower end shield has a simpler shape, thereby facilitating the manufacture of parts and reducing costs.

Note that the shape of the sharp end of the side lead is not limited to the shape shown in the above-described embodiment. For example, a tongue-like shape may be used as long as a chamfered portion is provided in advance on the side opposite to the surface facing the filament 1. Or other shapes.

〔The invention's effect〕

As described above, according to the method for manufacturing the magnetron filament support structure of the present invention, the laser welding means is used for welding the side lead end and the other end of the filament. The opposite surface and the opposite surface are chamfered in advance, laser irradiation is performed from the chamfered portion side, the chamfered portion is melted by this laser irradiation, and the other end of the filament and the side lead end are laser-welded Therefore, the chamfered portion of the side lead end is easily welded by irradiating the laser beam for a short time, the welded portion reaches the other end of the filament, and the side lead end and the other end of the filament are connected. Laser welding of
During this laser welding, the other end of the filament is not directly irradiated with laser light, so that the filament is not damaged, the laser welding operation can be simplified, and the side lead end and the filament can be reliably connected. There is an effect that laser welding with the other end side can be performed.

Further, according to the method for manufacturing a filament supporting structure of a magnetron of the present invention, it is possible to make the second end shield supported by the end of the side lead a simple shape for preventing unnecessary diffusion of electrons. Therefore, there is an effect that the manufacture of the second end shield is simplified and the manufacturing cost is reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a method for manufacturing a magnetron filament support structure according to the present invention, FIG. 2 is a cross-sectional view of a principal part explaining another embodiment of the present invention, and FIG. FIG. 4 is an explanatory view of a filament supporting structure of a magnetron according to a conventional technique. 1 ... filament, 1a ... one end of the filament, 1b ...
... the other end of the filament, 2 ... the center lead, 3 ...
Side lead, 4 ... Lower end shield, 4a ... Side lead insertion hole, 4b ... Center lead insertion hole, 5 ... Upper end shield, 6 ... Welded part.

Continuation of the front page (56) References Japanese Utility Model Sho 55-71443 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01J 9/04 H01J 23/04

Claims (1)

(57) [Claims] 1. A helical filament, a first end shield made of a refractory metal connected to one end of the filament, and a second end shield made of a refractory metal connected to the other end of the filament. A center lead that passes through the axis of the helical filament and supports the first end shield at an end, and supports the second end shield, and the end is laser-welded to the other end of the filament. A method of manufacturing a filament supporting structure of a magnetron comprising a side lead and a side opposite to the surface of the side lead end opposite to the filament in advance, and irradiating a laser from the chamfered portion side. Process, the chamfered portion ヲ melt,
A method for manufacturing a filament supporting structure for a magnetron, comprising manufacturing a filament supporting structure through a step of laser welding the other end of the filament and the end of the side lead.