JPS60101841A - Magnetron cathode structure - Google Patents

Abstract

PURPOSE:To improve vibration resistance without sacrifice of insulation performance by constructing such that the projected portion of insulation spacer will engage with the engaging section of lower end shield at the outside of through- hole of lower end shield. CONSTITUTION:An insulation spacer 19 has a projected portion 19d at the outside of the section corresponding with a through-hole 13a of lower end shield 13. An engaging section 13c made of a hole to be engaged with said projected portion 19d is made in the lower shield 13. Since said projected portion 19d will engage with the engaging section 13c of lower end shield 13 for rhe vibration in all directions, strength of filament will increase. While since the insulation spacer 19 is not inserted into the through-hole 13a of lower end shield 13, the amount of metal to be adhered to said spacer 19 will decrease considerably resulting in improvement of reliability.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to the cathode structure of a magnetron used in a microwave oven, etc., and particularly to the structure of the cathode of a magnetron used in a microwave oven, etc.
Concerning the structure of increasing degrees.

[Background of the invention]

The virtual image structure of a conventional magnetron consists of a structure as shown in FIG. That is, the upper and lower ends of a filament 1 formed by spirally winding thorium tungsten or the like are fixed to an upper end shield 2 and a lower end shield 3, respectively. The upper end shield 2 is fixedly supported at one end of a center lead disposed through a through hole of the lower end shield 3, and the lower end shield 3 is fixedly supported at one end of a side lead 5. The other ends of the center lead 4 and the side leads 5 are inserted into holes 6a provided in the insulator 6, and the gold! It is brazed to the lower end of the insulator 6 via a member 7. A sealing member 8 is brazed to the upper end of the +1!1 edge 6, and this sealing member 8 is further sealed to an anode (not shown). See you again.

An insulating spacer 9 is attached to the center lead 4 and side lead 5.
The insulating spacer 9 is fixed to the side lead 5 via a metal pipe 10 to improve the strength of the filament t.

By the way, in such a structure, since the center lead 4 and the side leads 5 are read directly by the filament l having spring properties, the center lead 4 and the side leads 5 have a fixed 4fI.
The kRwJ numbers are different. However, in the structure shown in FIG. 1, in response to vibrations in the direction parallel to the plane of the paper, that is, in the direction of arrow AA', the insulating spacer 9 acts in the direction of fixing the center lead 4 and the side leads 5, so that the upper end cylindrical The displacement of filament 1 due to the vibration of 2 is small, and P
, the edge spacer 9 exhibits its full effect. however,
In response to vibrations in the direction perpendicular to the plane of the paper, a so-called glasses-shaped spacer such as the insulating spacer 9 cannot reduce the displacement of the upper end shield 2, so the strength of the filament is an issue when using a vibration-prone device. It became.

Therefore, in order to improve this drawback, a 4-structure structure as shown in FIG. An insertion portion 9a of an insulating spacer 9 is inserted into the hole 3a.This structure is effective against vibrations in all directions.

However, in such a structure, the brazing between the filament l and the upper and lower end shields 2.3 is sometimes difficult, for example by Ku M
Since the brazing filler metal powder consisting of o is melted while adhering to the end surface 9b of the insulating spacer 9, the insulation of the end surface 9b deteriorates. Furthermore, the filament performed to activate the filament 1 is significantly deteriorated. In particular, V8W
When the magnetron is driven under operating conditions where I't is large, microwave t* flows to the end face 9b where the insulation has deteriorated,
This causes sparks and abnormal heating, as well as abnormal gas emissions, resulting in inoperability.

[Purpose of the invention]

-41 An object of the present invention is to provide a highly reliable magnetron cathode structure that is effective against vibrations in all directions and does not deteriorate the insulation properties of the insulating spacer.

[Summary of the invention]

The present invention provides a filament, upper and lower end shields that respectively support and fix the upper and lower ends of the filament, a center lead that is disposed through a penetration yc of the lower end shield and supports and fixes the upper end shield, and a center lead that supports and fixes the upper end shield. In a magnetron cathode structure including side leads that support and fix an end shield, and insulating spacers inserted into the center lead and the side leads, the insulating spacer faces toward the lower end of the through hole of the lower end shield. and a protruding portion protruding from a portion corresponding to the through hole of the lower end shield toward the lower end shield side from the lower facing surface of the lower end shield with the outer cylinder, The end shield is characterized in that it has a retaining part that engages with the protruding part of the insulating spacer.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be explained with reference to FIG. 3 and FIG. 4 of the cylinder. Note that the same members as in FIGS. 1 and 2 are designated by the same reference numerals, and their explanations will be omitted.

Holes 19a and 19b are formed in the insulating spacer 19, into which the center lead and the side leads 5 are inserted. The insulating spacer 19 can be fixed to the center lead 4 or side lead 5 by using the bent portion of the center lead 4 or side lead 5, or by welding or simply inserting a metal pipe into the center lead 4 or side lead 5. It is possible.

The insulating spacer 19 has a lower end shield lower facing surface 190 facing the lower end surface 13b of the through hole 13a of the lower end shield 13, and a lower end surface 190 of the through hole 13 of the lower end shield 13.
It has a protruding portion 19d that protrudes toward the lower end shield 13 from the lower end shield lower facing surface 19C on the outer side of the portion corresponding to M.

Further, the lower end shield 13 is formed with an engaging portion 13c which is a hole in which the protruding portion 19d of the insulating spacer 19 engages.

Therefore, the insulating sheave f
I 9 +7) Projection m 19d is the lower end shield!
3, the movable waves of the filament I can be made small, and the filament breaking strength is improved, as in the conventional example shown in FIG. Also lower end shield 13
Since the insulating spacer 19 is not inserted into the through hole 138, the amount of metal that evaporates and adheres to the lower end shield lower surface 19C of the insulating spacer 19 through the through hole 13a is smaller than that in the conventional example shown in FIG. Significantly reduced and reliability improved. In addition, by reducing the metal layer, v
Even if the magnetron is operated under high swrt conditions, #
4 No normal phenomena occur.

5 and 6 show other embodiments of the invention. A hole 29a into which the center lead 4 is inserted is formed in the center of the insulating spacer 29, and an escape groove 29b into which the side lead 5 is inserted is formed by cutting out a portion of the outer periphery. The insulating spacer 29 also has a through hole 2 in the lower end shield 23.
An annular protrusion 29d that protrudes from the upper lower end shield 231111 of the lower end shield lower facing surface 29C is formed on the outside of the lower end shield lower facing fIi 29C facing the lower end surface 23b of 3a. The lower end shield 23 is formed with a cylindrical retaining portion 23C that engages with the inner diameter portion of the protruding portion 29d of the insulating spacer 29.

Even if formed in this way, the same effects as in the embodiment described above can be obtained. In other words, for vibrations in various directions, the protrusion 29
This is prevented by engaging the inner diameter portion of d and the outer circumference of the retaining portion 23C. Further, since the insulating spacer 29 is not inserted into the through hole 23a, the amount of metal that evaporates and adheres to the lower end shield lower facing surface 29C is reduced.

FIG. 7 shows a modification of the insulating spacer 29 shown in FIG. In this embodiment, the relief sleeves 29b into which the side leads 5 are inserted are formed symmetrically. When formed in this way, the side lead 5 can be inserted into either side of the relief 29b, making assembly easier.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the -/- insulating spacer is not inserted into the through hole of the lower end shield, and the protrusion of the insulating spacer outside the through hole of the lower end shield is inserted into the lower end. Since it is configured to be secured to the securing portion of the shield, it is possible to obtain a highly reliable magnetron that is effective against vibrations in all directions and does not deteriorate the insulation properties of the insulating spacer.

[Brief explanation of the drawing]

1 and 2 are sectional views of the conventional example, FIG. 3 is a sectional view showing an embodiment of the present invention, FIG. 4 is a perspective view of the insulating spacer shown in FIG. 3, and FIG. 5 is a sectional view of the insulating spacer of the present invention. FIG. 6 is a perspective view of the e5 edge spacer shown in FIG. M5, FIG. 7 is a modified example of the insulating spacer shown in FIG. Figure, (b) is a sectional view. l...Filament, 2...Top end shield, 4...Center lead, 5...Side lead,
15.23...Lower end shield, 13a, 2
3a...through hole, 13b, 23b...lower end surface, t3c, 23cm...engaging portion, 19, 29.
, , Insulating spacer, 19a, 2 (jlm-hole, 1
9b-・8-・・Hole, 29b・・Escape N, 19c, 29c・
...Lower end shield lower surface facing surface, 19d, 29
d... Protrusion. Figure 7 (CL) (b)

Claims (1)

[Claims] A filament, upper and lower end shields that respectively support and fix the upper and lower ends of the filament, a center lead that is disposed through a through hole in the lower end shield and that supports and fixes the upper end shield, and supports the lower end shield. The side leads to be fixed and at least the center 1. Do studies≠←? In the cathode structure of the magneto tube, the insulating spacer is connected to a lower surface opposing surface of the lower end shield opposite to the lower end surface of the through hole of the lower end shield, and an insulating spacer inserted in the lower end shield. The F end shield has a protruding portion that protrudes outward from a portion corresponding to the through hole and toward the lower end shield from the opposing surface of the lower surface of the lower end shield, and the F end shield has a retainer with which the protruding portion of the insulating spacer engages. having a joint,
The characteristic @polar structure of the magnetron.