JPH07201285A - Magnetron - Google Patents

Abstract

PURPOSE:To conduct the exhaust in a short time, and prevent the deterioration of the degree of vacuum after manufacturing a product by providing a hole or a notched part in a shield member where a brazed part of antenna ceramics is shielded to prevent formation of the sealed space within a magnetron. CONSTITUTION:A hole 10c is provided in a bar ring 10a of a shield member 10 fixed to a top shell 7 by brazing or the like. The hole 10c is provided at a part away from the part to be brazed on the tip part of the bar ring 10a. Thus, the hole is not covered with the brazing filter metal. This constitution prevents the spark between an antenna ceramics 8, a top shell 7, a brazed part 9 and an antenna, and prevents the deterioration of the exhaust speed or the deterioration of the degree of vacuum after manufacturing the product.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to magnetrons.
More specifically, it is possible to facilitate gas release in the gap between the brazing part of the antenna ceramics and the shield member that shields the brazing part, to shorten the exhaust time, and to reduce the degree of vacuum after commercialization. Not about a reliable magnetron.

[0002]

2. Description of the Related Art A magnetron generally used in a microwave oven has a structure as shown in FIG. That is, an anode portion, which is a cavity resonator, is formed from the even number of vanes 2 and the strap ring 3 that are radially provided on the inner circumference of the anode cylinder 1, and a high voltage is applied between the cathode portion and the filament portion 4. The magnetic field is applied in the direction perpendicular to the electric field (axial direction of the anode cylinder 1) via the pole piece 5 to apply the orthogonal electrostatic magnetic field.
The microwave energy generated at the anode part of the magnetron is radiated to the outside from the antenna 6 connected to the vane 2. A vacuum wall is formed around the antenna 6 by the top shell 7 brazed to the anode cylinder 1, the antenna ceramics 8 that transmits microwaves, and the seal portion 11.

Top shell 7 and antenna ceramics 8
In the brazing part 9 and the burrs of the brazing material are likely to occur, and a spark is likely to occur between the brazing material and the antenna 6. When a spark is generated, a pinhole is formed in the brazing part 9 between the top shell 7 and the antenna ceramics 8, or the antenna ceramics 8 is cracked and the vacuum wall is destroyed, so that the sparks do not occur in the brazing part. A shield member 10 made of a conductive material and electrically connected to the top shell 7 is provided on the inner circumference of the brazing portion. By doing so, the occurrence of sparks is prevented.

The shield member 10 for shielding the brazing portion of the antenna ceramics 8 shown in FIG. 4 and shown in Japanese Utility Model Publication No. 58-910, for example, is brazed to the top shell 7 by the burring portion 10a. It is a fixed ring-shaped metal. As described above, the shield member 10 has a function of preventing spark (discharge) between the antenna 6 and the brazing portion 9 of the antenna ceramics 8 and preventing cracking of the ceramic and formation of pinholes in the brazing portion. It is an essential component for improving reliability.

On the other hand, since the shield member 10 needs to be spaced apart from the antenna 6, it is necessary to make the inner diameter of the ring as large as possible. Therefore, the shield member 10
The front end portion 10b of the is fixed to the antenna ceramics 8 in a state of being close to or in contact therewith.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the magnetron provided with, the shield member 10
A space A surrounded by the top shell 7 and the antenna ceramics 8 is formed. Especially the tip 10 of the shield member 10
When the shield member 10 is fixed while b is in contact with the antenna ceramics 8, the space A becomes a hermetically sealed state, the gas in the space A does not easily escape during the exhaust of the magnetron, and the exhaust process takes a long time, and the product There is a problem that the gas remaining in the space A after being diffused diffuses to lower the degree of vacuum.

Particularly, when the degree of vacuum inside the magnetron is reduced after the product is commercialized, there are problems that electrical characteristics such as easy mode jumping are deteriorated and deterioration of the cathode is accelerated to shorten the life.

The present invention solves such a problem and provides a highly reliable magnetron in which a sealed space is not formed in the magnetron, exhaust can be performed in a short time, and the degree of vacuum is not lowered after being manufactured. With the goal.

[0009]

A magnetron according to the present invention has an output section consisting of an antenna connected to an anode section and an antenna ceramics which is a part of a vacuum wall provided around a part of the antenna. In the magnetron having, a shield member for shielding a brazing part between an end portion of the antenna ceramics and a top shell to the antenna is provided integrally with the top shell or fixed to the top shell, and the shield is provided. The member is provided with a hole or a notch.

[0010]

According to the present invention, since the shield member for shielding the brazing portion of the antenna ceramic is provided with the hole or the notch, the inner diameter of the shield member is made as large as possible so that the tip of the shield member contacts the antenna ceramic. However, the space surrounded by the shield member, the antenna ceramics, and the top shell does not become a hermetically sealed state. As a result, the gas in this space is quickly exhausted from the hole or notch provided in the shield member, and the exhaust time can be shortened. Does not spread.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the magnetron of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view of a portion to which a shield member of one embodiment of the magnetron of the present invention is fixed, and FIG. 2 is a partial cross-sectional view and a top of a portion of a magnetron of another embodiment of the present invention to which a shield member is fixed. FIG. 3 is an explanatory view of a shell portion, and FIG. 3 is a perspective view and an explanatory view of a shield member of still another embodiment of the magnetron of the present invention.

FIG. 1 is a view showing a portion of the shield member, and the other structure of the magnetron is the same as the structure shown in FIG. The present embodiment is characterized in that a hole 10c is provided in the burring 10a of the shield member 10 that is fixed to the top shell 7 by brazing or the like. Since the hole 10c is provided apart from the brazed portion of the tip of the burring 10a, it is not blocked by the brazing material during brazing. The hole 10c is not limited to the flat portion of the bar ring 10a, which is the flange portion on the bottom surface of the shield member 10, and may be provided at the base portion of the cylindrical ring or the cylindrical ring portion.
The point is that it is a hole that communicates with the space A surrounded by the shield member 10, the antenna ceramics 8 and the top shell 7.

For example, at an oscillation frequency of 2450 MHz, the output is
Inner diameter D of the shield member 10 in a 600 W magnetron
Is 9.5 to 11 mm, the width B of the burring 10a is 2 to 3 mm, and the diameter of the hole 10c at this time may be about 0.5 to 1.5 mm. The holes 10c do not need to be provided at equal intervals or the same size, and may be provided at random. In addition,
The thickness of the shield member is about 0.25 to 0.40 mm. This hole
10c can be formed at the same time when the shield member 10 is molded with a mold, and the number of steps does not increase because of the hole formation.
As a result, a spark between the antenna ceramics 8 and the brazing portion 9 between the top shell 7 and the antenna can be prevented, and the exhaust speed and the vacuum degree after the product is not reduced.

FIG. 2 (a) is a view showing a portion of a shield member of another embodiment of the magnetron of the present invention, and FIG. 2 (b) is a perspective view of a top shell portion and a sectional explanatory view thereof. The present embodiment is characterized in that the top shell 7 and the shield member 10 are integrally formed of the same material, and that the shield member 10 portion is provided with a hole 10c communicating with the space A similar to the previous embodiment. . That is, in the present embodiment, the tip of the top shell 7 and the antenna ceramics 8 are not brazed by butting, but the antenna ceramics 8 and the antenna ceramics 8 are brazed by the convex portions of the top shell 7 bent in a dogleg shape. The end portion bent in a dogleg shape is further bent to the antenna ceramics 8 side to form the shield member 10. The tip end side of the shield member 10 becomes a vacuum wall from the bent dogleg shape. Becomes irrelevant. Therefore, even if the hole 10c is formed in the bottom, the vacuum tube wall is not damaged, and the gas in the space A can be easily exhausted. The holes 10c can also be formed at the same time when the top shell 7 is formed by die processing, and the dimensional relationship such as the size of the holes is similar to that of the above-described embodiment.

FIGS. 3A and 3B show another embodiment of the shield member 10 portion in which the top shell 7 and the shield member 10 are integrally formed. FIG. 3A shows an example in which the hole 10c is provided not at the bottom of the shield member but at the bent portion, and the other points are the same as in the above embodiment. The hole 10c can be formed in such a bent portion by forming the hole 10c and then performing the bending process. Even if the bent portion is provided with the hole 10c, the interior of the magnetron communicates with the space A, so that the space A is quickly exhausted.

FIG. 3B shows an example in which a slit-shaped cut portion 10d is formed in the cylindrical ring portion of the shield member 10. If most of the antenna and the brazing portion are shielded, no spark is generated, and even with such a structure, the gas in the space A can be efficiently discharged. In order to form the cutout portion as in this embodiment, it is possible to easily form the cutout portion by adopting a processing method of performing a bending step after the cutout step. The width of the notch portion can be provided with slits of about 0.5 to 1.5 mm at intervals of about 2 to 5 mm with respect to the shield member of the above size. However, like the above-mentioned holes, it is not necessary to provide these slits at even intervals, and even if several slits are provided at random, it is sufficiently effective.

Both of these holes and notches may be provided, or they may be formed at random. In short, the cross-sectional area of the hole or notch is the magnetron of the above example (oscillation frequency is 2450MHz, the inner diameter of the shield member is 9.5 ~
(About 11.5 mm), if it is provided with a size of about ² to 20 mm ² , it is possible to obtain a magnetron that does not affect the exhaust speed or the deterioration of characteristics after commercialization.

[0018]

According to the present invention, although the shield member for shielding the brazing part of the antenna ceramics is provided, the exhaust in the magnetron can be exhausted in a short time, and the antenna and the antenna ceramics can be exhausted. It is possible to prevent sparks between the brazing part and a high-performance magnetron with high vacuum and high reliability without increasing the number of manufacturing steps.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a shield member portion of an embodiment of a magnetron of the present invention.

FIG. 2 is a cross-sectional explanatory view of an output part and an explanatory view of a top shell part of another embodiment of the magnetron of the present invention.

FIG. 3 is an explanatory view of a shield member and a top shell portion of another embodiment of the magnetron of the present invention.

FIG. 4 is an explanatory diagram of an example of a magnetron for a microwave oven.

[Explanation of reference numerals] 6 antenna 7 top shell 8 antenna ceramics 9 brazing portion 10 shield member 10c hole 10d notch portion

Claims (1)

[Claims] 1. A magnetron having an output part comprising an antenna connected to an anode part and an antenna ceramics part of a vacuum wall provided around a part of the antenna, the magnetron comprising: A shield member that shields the brazing portion of the end portion and the top shell to the antenna is provided integrally with the top shell or fixed to the top shell, and the shield member is provided with a hole or a notch portion. It is a magnetron.