JPH01124939A - Magnetron - Google Patents

Abstract

PURPOSE:To make it possible to suppress the generation of unwanted radiated electromagnetic waves in a working space by short-circuiting a large number of rectangular anode vanes at every other locations only on the one side of the cathode terminal lead out side with a pair of anode straps of smaller and larger diameters. CONSTITUTION:A large number of rectangular anode vanes 3a, 3b,... projecting from positions divided by an equal angle on the inner circumference of an anode cylinder 1 toward a cathode side 2 are short-circuited at every other locations on the cathode terminal lead out side only of two sides along the direction of the projection by means of a pair of anode straps 4a, 5a of smaller and larger diameter. However, when a mean radius of the paired anode straps 4a, 5a is assumed to be Rs and the inside radius of the anode cylinder to be Ra, they are set in the relationship of Rs>=Ra/2.2. This makes it possible to reduce the difference in the high frequency electric field intensity on the microwave lead out side edge of the anode vane and to suppress unwanted high frequency radiation amount produced by leakage of high intensity, high frequency electric field locally into a working space.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetron used in microwave heating equipment such as a microwave oven.

BACKGROUND ART In general, a magnetron as described above is constructed as shown in FIG. The vanes 3a, 3b, 3c, . . . are a pair of pressure equalizing rings 4a, 5a; 4b having a small diameter and a large diameter on each of the two sides along the protruding direction.

5b, every other one is short-circuited. Then, one of the many anode vanes, for example, anode vane 3.
One end of an elongated microwave output conductor 6 is fixed to a, and the other end of this conductor 6 is fixed to a tip-off portion of a metal exhaust pipe 7. 8 is a cap-shaped microwave output terminal, 9 is a ceramic insulating ring, 10 is a metal tube for sealing,
Reference numeral 11 indicates a magnetic pole piece, and 12a and 12b indicate lead members for leading out the cathode terminal.

Problems to be Solved by the Invention Incidentally, in the magnetron configured as described above, a pair of pressure equalizing rings 4b and 5 are provided on the side of the microwave output deriving section.
The high-frequency electric field distribution differs as shown in Fig. 4 depending on whether or not the equalizing rings 4b and 5b are provided, and the high-frequency distribution characteristic a when a pair of pressure equalizing rings 4b and 5b is provided is the same as that when not provided. It has a strong high-frequency electric field part that cannot be detected.

In this way, in conventional magnetrons, a strong high-frequency electric field is generated, especially on the side of the microwave output derivation section, so a large potential difference occurs between positions along the protruding direction of the anode vane, and this causes a high-frequency electric field in the working space. There was a problem in that the noise was locally strong and it was easy to generate unnecessary harmonic radiation (noise).

Means for Solving the Problems The present invention was made to reduce the occurrence of such unnecessary radiation, and includes a large number of rectangular anode vanes protruding toward the cathode from equiangularly divided positions on the circumferential surface of the anode cylinder. are short-circuited every other time by a pair of pressure equalizing rings with a small diameter and a large diameter only on one side on the cathode terminal outlet side of the two sides along the protruding direction, and the average of the pair of pressure equalizing rings is Between the radius Rs and the inner radius Ra of the anode cylinder, Rs≧Ra/2.
Let there be two relationships.

Function: With this configuration, it is possible to reduce the potential difference between positions along the protruding direction of the anode vane, and it is possible to reduce the generation of noise mixed into the microwave output.

Embodiments Next, the present invention will be explained in detail with reference to embodiments shown in the drawings.

Referring to FIG. 1, a large number of rectangular anode vanes 3at, 3be, 3c, . A pair of pressure equalizing rings 4a having a small diameter and a large diameter only on the cathode terminal outlet side of the two sides along the .

Every other one is short-circuited by 5a. Among the many anode vanes, for example, anode vane 3a
One end of an elongated microwave output conductor 6 is fixed to the wafer, and the other end of the conductor 6 is fixed to a tip-off portion of a metal exhaust pipe 7, as in the prior art. however,
When the average radius of the pair of pressure equalizing rings 4 a e 4 b is Rs, and the inner radius of the anode cylinder 1 is Ra, Rs≧Ra
/ 2 , 2 relationship is set.

The fifth harmonic unnecessary discharge resistance with respect to the average radius Rs of the pair of pressure equalizing rings 4a and 5a has the relationship shown in 2nd rM, and when Rs is Ra/2.2, it is -27.5 dB of the standard, and R8 is By exceeding Ra/2, 2, the standard is exceeded. That is, when Rs≧Ra/2, 2, the high-frequency potential difference between both ends of the anode vane in the protruding direction is small, and the generation of unnecessary radio waves in the working space is suppressed.

Effects of the Invention Since the present invention is configured as described above, it is possible to reduce the difference in high frequency electric field strength at the edge of the microwave lead-out bond of the anode vane, and to reduce harmonics caused by locally strong high frequency electric field leaking into the working space. Unnecessary waves (withstanding capacity) can be suppressed. Also, since only one pair of equalizing rings is used, the manufacturing process can be simplified and material costs can be reduced.

[Brief explanation of the drawing]

Figure 1 is a side cross-sectional view of the main parts of a magnetron embodying the present invention, Figure 2 is a characteristic diagram showing the relationship between the average radius of a pair of pressure equalizing rings and the amount of unnecessary harmonic radiation, and Figure 3 is a conventional FIG. 4 is a side cross-sectional view of a portion of the magnetron, and is a high-frequency electric field distribution characteristic diagram along the protruding direction of the anode vane. 1... Anode cylinder, 2... Cathode N 3a
, 3b: Old: Anode vane, 4a: Small diameter pressure equalizing ring s5a: Large diameter equalizing ring, 8: Old...
・Microwave output terminal. Name of agent: Patent attorney Toshio Nakao
Shoulder Jin, Figure 2, F “-Gong/E Dark Handcrafted Mystery (~) Figure 3, Figure 4

Claims (1)

[Claims] A large number of rectangular anode vanes protrude toward the cathode from equiangularly divided positions on the circumferential surface of the anode cylinder. A pair of large-diameter pressure equalizing rings short-circuit every other ring,
A magnetron characterized in that the average radius Rs of the pair of pressure equalizing rings and the inner radius Ra of the anode cylinder have a relationship of Rs≧Ra/2.2.