JPH0815053B2 - Magnetron - Google Patents

Description

TECHNICAL FIELD The present invention relates to a magnetron used in microwave heating equipment such as a microwave oven.

2. Description of the Related Art A magnetron used in a microwave heating device such as a microwave oven is usually configured as shown in FIG. 3, and an anode cylinder 1 is directed toward a cathode 2 located on a central axis. It has a large number of rectangular anode vanes 3a, 3b, 3c ... Which form a cavity resonator by protruding, on the inner peripheral surface, and has a mortar-shaped first pole piece 4 at one opening end, and Second mortar-shaped second magnetic pole pieces 5 are attached to the other open ends. In addition, the elongated microwave output lead-out conductor 6 having the base end fixed to the anode vane 3a, which is one of the anode vanes, has a circular through hole 7 formed in the inclined surface of the first magnetic pole piece 4. To the microwave output terminal 8 which also serves as an exhaust pipe.

The cavity resonator has a magnetron oscillation frequency of 2
Since high-order harmonic components having a frequency equivalent to double or triple are accumulated, a cylindrical harmonic component is provided on the output terminal side so that these harmonic components are not taken out to the microwave output terminal 8 together with the fundamental wave component. A choke 9 for blocking wave components is provided, and the choke 9 has a length L corresponding to an electrical length of 1/4 of the wavelength λ of the harmonic wave to be blocked.

The microwave output terminal 8 is an insulating ring made of ceramic.
It is sealed to the eyelet-shaped first metal tube 11 through 10.
The outer peripheral edge of the flange of the metal tube 11 is hermetically sealed to the open end of the anode cylinder 1. Reference numerals 12 and 13 denote cathode terminal lead-out conductors, which penetrate a stem insulator (not shown) hermetically sealed to an eyelet-shaped second metal tube 14 which covers the second magnetic pole piece 5 with a flange portion in an airtight manner. Extends outside the tube.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the conventional magnetron configured as described above, the microwave output terminal portion has the cylindrical harmonic component blocking choke, which not only increases the manufacturing cost but also increases the output terminal portion. It is difficult to shorten the side. In particular, in the case where various types of chokes are provided to prevent the leakage of a plurality of higher harmonic components, the electrode structure becomes more complicated, which makes it more difficult to reduce the cost and downsize.

Means for Solving the Problems The present invention has been made to solve the above-mentioned conventional problems, and according to the magnetron of the present invention, a magnetic pole provided at one opening end of the anode cylinder. The through hole of the piece is not circular but is a slot having an elongated planar shape. The conductor is configured to penetrate the slot substantially along the longitudinal direction of the slot, and the conductor is partially covered by a tongue-shaped portion extending from the peripheral edge of the slot.

Operation With this structure, the tongue-shaped portion can play the role of a choke that prevents leakage of harmonic components to the output terminal portion side. Therefore, the choke structure on the output terminal portion side can be simplified and the space can be reduced. Is possible.

EXAMPLES Next, the present invention will be described in more detail with reference to the examples shown in the drawings.

As shown in FIG. 1, the mortar-shaped magnetic pole piece 15 provided at one opening end of the anode cylinder 1 contacts the microwave output lead-out conductor 16 extending from the anode vane as described above. It has a through hole 17 that allows it to pass through without
The slot 17 is not a circle but a slot having an elongated planar shape. The conductor 16 penetrates the slot substantially along the longitudinal direction of the slot and is partially covered by a tongue-shaped portion 18 extending from the peripheral edge of the slot. However, the tongue-shaped portion 18 is formed by cutting and raising a part of the pole piece 15, that is, the edge portion of the pole piece 15 when the slot is formed, and the tip edge bent so as to cover the conductor portion traversing the slot from above. And the protrusion length L substantially matches the electrical length of 1/4 of the wavelength of the harmonic wave to be blocked.

The microwave energy generated in the cavity resonator is transmitted to the microwave output terminal portion through the microwave output lead-out conductor 16, but in the process of passing through the through hole 17 formed of the slot, the choking action by the tongue portion 18 is generated. As a result, the harmonic component, which is formed by the size of the protrusion length L, is attenuated.

In the embodiment shown in FIG. 2, the tongue-like portion 18 formed by cutting and raising the magnetic pole piece 15 is located approximately in the middle in the longitudinal direction of the through hole 17, which is a slot, and the protruding length L thereof.
Is almost equal to the electrical length of 1/4 of the wavelength of the harmonic wave to be blocked.

Of course, in addition to such a choke structure, for example, a cylindrical choke structure as shown in FIG. 3 may be used together to block different harmonic components.

EFFECTS OF THE INVENTION As described above, according to the present invention, a choke for attenuating a harmonic component leaking from the cavity resonator to the output terminal portion is provided with a long and narrow through hole formed in the pole piece and this through hole. Since it is composed of the tongue-shaped portion extending from the peripheral edge, a space for it is not required, and it is possible to reduce the manufacturing cost and downsize the magnetron. Further, it becomes possible to dispose various choke members while keeping the space in the pipe to a minimum.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part of a magnetron embodying the present invention, and FIG. 2 is a perspective view of an essential part of another embodiment of the present invention.
The figure is a partial cross-sectional view of a conventional magnetron. 1 ... Anode cylinder, 15 ... Pole piece, 16 ... Microwave output derivation conductor, 17 ... Through hole, 18 ... Tongue-shaped part.

Claims (1)

[Claims] 1. A through hole penetrating an elongated microwave output lead-out conductor extending from an anode vane, which is formed in a pole piece provided at one opening end of an anode cylinder, has an elongated planar shape. The magnetron, wherein the conductor has a slot, and the conductor penetrates the slot substantially along a longitudinal direction of the slot and is partially covered by a tongue-shaped portion extending from a peripheral edge of the slot.