KR100292483B1 - Structure for preventing the high order harmonic waves in magnetron - Google Patents

Abstract

PURPOSE: A structure for preventing generation of harmonics in a magnetron is provided to prevent the generation of harmonics by improving a structure of a magnetron. CONSTITUTION: A magnetron is formed with a cylindrical anode body, a multitude of vanes(2') arranged within the cylindrical anode body, a filament for forming a cathode portion, and an antenna for emitting high frequency energy to an outside. A vane(2') has a predetermined area and a predetermined thickness. The vane(2') has a curved upper portion and a curved lower portion. The curved upper portion and the curved lower portion of the vane(2') are formed by curves having predetermined radiuses. Grooves(H) combined with an inner strap(N) and an outer strap(T) are formed on an upper end portion and a lower end portion of the vane(2'), respectively.

Description

Harmonic generation prevention structure of magnetron {STRUCTURE FOR PREVENTING THE HIGH ORDER HARMONIC WAVES IN MAGNETRON}

The present invention relates to a harmonic generation prevention structure of a magnetron, and more particularly, to a harmonic generation prevention structure of a magnetron to prevent the generation of unnecessary harmonics as well as simplify the structure.

In general, a microwave oven puts food into a cooking chamber for cooking food, and then fires the food by firing high frequency (MICROWAVE) in the cooking chamber to cook. The high frequency emitted to the cooking chamber in the microwave is made by the magnetron (MAGNETRON).

1 is a cross-sectional view showing an example of the magnetron, as shown in the magnetron, a plurality of vanes 2 are assembled radially inside a cylindrical anode body 1 having a predetermined internal space. Resonant cavities are formed from the anode body 1 and the vanes 2. In addition, a filament 3, which is a cathode, is installed at the center of the anode main body 1 to form an interaction space between the vane 2 and the filament 3. The vanes 2 are formed in a straight plate having a rectangular cross section so as to have a predetermined length, and the vanes 2 are coupled to the inner diameter of the anode main body 1 so as to be equally spaced from each other, and between the vanes 2. The interval of is formed to be in resonance with the desired frequency band to form a resonator. In addition, an inner strap N and an outer strap T are coupled to upper and lower portions of the vanes 2 to stabilize the resonant frequency. The anode body 1 is an anode and the filament 3 forms a cathode to form a two-pole vacuum tube. 2 is a front view and a side view of the vane.

The filament (3), which is the cathode portion, emits hot electrons by flowing a current between the center lead (4) and the side lead (5) coupled thereto, and the released hot electrons are applied to the strong electric field and the permanent magnet applied between the cathode and the anode. The high frequency energy is generated by the magnetic field.

Then, in order to apply the magnetic flux to the working space, the magnetic closing circuit is composed of the permanent magnet 6, the box pole 7, the defect pole 8, the upper yoke plate 9 and the lower yoke plate 10, and the filament 3 And an antenna 11 installed at the side of the anode main body 1 and connected to the vanes 2 to extract and radiate high frequency energy generated in the working space.

The cylindrical ceramic 12 and the acyl 13 are hermetically coupled to the antenna 11 so as to be positioned above the yoke top plate 9, and emit unnecessary electromagnetic waves inside the acyl 13. An output side choke 14 for suppressing the coupling is coupled, and a gasket 15 for preventing electromagnetic leakage when the magnetron is mounted on the side of the microwave is coupled to the side.

In addition, between the anode main body 1 and the inside of the yoke lower plate 10, a cooling fin 16 for dissipating heat converted by high frequency energy that is not emitted out is provided, and the lower part of the lower yoke plate 10 is provided. Filter box 17 is coupled to prevent unnecessary harmonic components leaking to the input. In addition, the F chamber 18, the f ceramic 18, and the ceramic spacer 20 are coupled to the inside of the filter box 17 to support the filament 3, which is a cathode part.

The magnetron as described above is mounted inside the machine room of the microwave to emit high frequency into the cooking chamber.

On the other hand, microwaves generally heat the food using electromagnetic waves in the 2.45 GHz band, where harmonics are generated in addition to the fundamental wave. Among the harmonic components, the fifth harmonic component (12.25 GHz), which is a five-fold band of the fundamental wave 2.25 GHz, corresponds to the 11.7 to 12.7 GHz band of the broadcasting satellite program, thereby restricting the leakage of the fifth harmonic.

The magnetron has a structure for reducing the radiation or leakage of unnecessary electromagnetic waves, such as the fifth harmonic included in the oscillation output, in particular, and a metallic cylindrical choke having a length of almost lambda / 4 having an unnecessary harmonic wavelength is disposed.

However, the conventional structure for suppressing the generation of unnecessary harmonics in the magnetron is to install several chokes 14 made of a metallic cylinder to suppress unnecessary electromagnetic waves transmitted or radiated through the antenna 11 to additionally use the component. Not only that, there is a problem that the production cost is increased due to the addition of the assembly process, thereby lowering the assembly productivity.

Accordingly, it is an object of the present invention to provide a harmonic generation prevention structure of a magnetron that not only prevents generation of unnecessary harmonics but also simplifies the structure.

1 is a cross-sectional view showing the structure of a typical magnetron,

2 is a front view and a side view showing the vanes of the conventional magnetron,

3 is a perspective view illustrating a vane constituting the magnetron harmonic generation preventing structure and a coupling structure thereof of the present invention;

4 is a front view and a side view showing the structure of the vanes constituting the magnetron harmonic generation prevention structure of the present invention,

5 is a perspective view showing another embodiment of the vane constituting the magnetron harmonic generation prevention structure of the present invention,

6 is a front view and a side view showing another embodiment of the vane constituting the magnetron harmonic generation prevention structure of the present invention,

7 is a front view showing the flow of the electromagnetic field between the vanes in the magnetron harmonic generation prevention structure of the present invention.

(Explanation of symbols for the main parts of the drawing)

One ; Anode body 2 ', 2 "; vane

3; Filament 11; antenna

14; Chouk

In order to achieve the object of the present invention as described above, the anode body is formed in a cylindrical shape to form an anode portion, a plurality of vanes are formed to have a predetermined thickness and area and are arranged radially inside the anode body and assembled; And an antenna that forms an interaction space with the vanes in the center of the anode body and is coupled to connect with the vane and the filament constituting the cathode portion to extract the high frequency energy generated in the interaction space and radiate to the outside. A magnetron comprising; The vane has a phase difference in which the upper and lower parts are symmetric about a horizontal center line, and the vanes are formed to be bent such that the total of the field strengths between the vanes and the vanes becomes zero.

The upper and lower portions of the bent vanes are provided with a harmonic generation preventing structure of the magnetron, characterized in that formed in a curved surface having a predetermined radius of curvature.

The upper and lower portions of the bent vanes are provided with a harmonic generation prevention structure of the magnetron, characterized in that it has a straight surface.

Hereinafter, the magnetron harmonic generation prevention structure of the present invention will be described according to the embodiment shown in the accompanying drawings.

The magnetron harmonic generation preventing structure of the present invention is formed in a cylindrical shape to form an anode main body 1 and a predetermined thickness and area, and a plurality of radially arranged inside the anode main body 1 assembled Two vanes (2) and the filament (3) and the vanes (2) which are installed to form an interaction space with the vanes (2) at the center of the anode main body (1) and form a cathode part, The antenna 11 which extracts the high frequency energy generated in the interaction space and radiates to the outside is the same as the conventional art. As shown in FIG. 3, each of the plurality of vanes 2 ′ radially arranged and assembled in the inner diameter of the anode main body 1 has a phase difference in which the upper and lower parts are symmetric about the horizontal center line It is formed to be bent.

As shown in FIG. 4, the vanes are formed to have a predetermined area and a predetermined thickness, and the bent upper and lower portions are formed as curved surfaces having a predetermined radius of curvature. In addition, the upper and lower ends of the vanes 2 'are formed with grooves H to which the inner strap N and the outer strap T are coupled as in the prior art.

In addition, as another embodiment of the present invention, as shown in Figure 5, the upper and lower portions of the bent vane is formed to have a straight surface. In addition, the vanes 2 "bent in a straight line are formed to have a predetermined area and a predetermined thickness, as shown in Fig. 6, and the upper and lower bent portions have a straight surface and are bent inward to each other. In the upper and lower ends of the vanes 2 ″, grooves H to which the inner strap N and the outer strap T are coupled are formed, as in the prior art.

Hereinafter, the effects of the magnetron harmonic generation prevention structure of the present invention will be described.

First, between each vane 2 'and vanes 2' assembled to be radially arranged in the inner diameter of the anode body 1 formed in a cylindrical shape, the vane 2 'becomes a resonance space to make a resonance with respect to a desired frequency band, that is, 2.45 GHz. In the arrangement, the vanes 2 'and the vanes 2' form a resonator. In such a structure, hot electrons are emitted by flowing a current between the center lead 4 and the side lead 5 coupled to the filament 3 which is the cathode, and the hot electrons are discharged from the strong electric field applied between the cathode and the anode. The magnetic field by the permanent magnet generates high frequency energy in the interaction space, which is the space between the vane and the filament (3). From the high frequency energy generated in the interaction space, the resonant frequency set in the resonator of the vane 2 ', that is, the high frequency energy corresponding to the 2.45 GHz band is resonated in the resonator and externally through the antenna 11 installed in the vane 2'. Is radiated to. In the resonator, not only the 2.45 GHz band frequency but also harmonics plurally multiplying together, in which the harmonics resonating together as well as the fifth harmonic band, which is the regulation region, are not interfered with each other by the phase difference between the upper and lower vanes 2 '. It is canceled or eliminated. FIG. 7 schematically shows the interaction flow of the electromagnetic field strength E5 in which the shape of the vanes 2 'according to the present invention dissipates or cancels harmonics such as the fifth harmonic. As shown in FIG. The distribution of the electromagnetic field is made along the phase of the surface, which forms a symmetrical surface around the line of symmetry, and the sum of the field strengths in the region becomes zero. That is, the current formula (I) of the harmonics to be suppressed in the vanes, for example, the fifth harmonic, is expressed as follows.

이식에서 오른쪽 텀(Term)이 제로, 즉 '0'이 되어야 한다.I =

The right term in the transplant should be zero, ie '0'.

The main parameter for canceling the harmonics in the curved vanes 2 'is the height h of the curved surface, which can be obtained by calculation. That is, the sum of the intensity of the electromagnetic field between the vanes 2 'and the vanes 2' of the fifth harmonic, which is to be extinguished as described above, should be zero in total, and the conditions for becoming zero are derived to a constant value. The curved surface is calculated by a proportional expression of the wavelength and phase value of the resonant circuit made between the actual vane 2 'and the vane 2' with a constant value, that is, a phase value and a wavelength that makes the intensity of the electromagnetic field zero. We can get the height of. Of course, the actual dimensions inside the resonator, such as the diameter of the circle consisting of the vane (2 ') and the inner surface forming the resonant circuit should be known.

As described above, by forming the curved surface of the vane 2 'properly, it is possible to prevent the generation of unnecessary harmonics such as the fifth harmonic. In addition, it is possible to eliminate the use of the choke 14 made of a metallic cylinder provided on the side of the antenna 11 in order to suppress the generation of unnecessary harmonics.

As described above, the harmonic generation prevention structure of the magnetron according to the present invention forms the shape of each vane assembled and arranged radially in the inner diameter of the anode main body so that the upper and lower parts are curved to form a symmetrical shape so that they are unnecessarily resonated. By preventing the generation of harmonics, such as the fifth harmonic, it is possible to fundamentally prevent the generation of unnecessary harmonics in the resonance space, whereby the use of a choke made of a metallic cylinder installed on the side of the antenna to suppress the leakage of unnecessary harmonics. By eliminating this, the number of parts is reduced and the structure is simplified, thereby reducing production costs and improving assembly productivity.

Claims (3)

An anode body formed in a cylindrical shape to form an anode portion, a plurality of vanes formed to have a predetermined thickness and area and arranged radially inside the anode body, and the vanes in the center of the anode body; A magnetron formed to form an interaction space and coupled to the filament forming the cathode portion and connected to the vane, and an antenna configured to extract high frequency energy generated in the interaction space and radiate to the outside; The vane has a phase difference in which the upper and lower parts are symmetric about a horizontal center line, and the vanes are formed to be bent such that the sum of the field strengths between the vanes and the vanes becomes zero. The structure of claim 1, wherein the upper and lower portions of the bent vanes are formed in a curved surface having a predetermined radius of curvature. The structure of claim 1, wherein the upper and lower portions of the bent vanes are formed to have a straight surface.

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