KR19990008952A - magnetron - Google Patents

Abstract

The present invention relates to a magnetron, and by forming the outer lower end of the top shield in a chamfered or curved shape to facilitate fastening with the filament, not only can the assembly of the top shield and the filament be improved, but also the image between the filament and the vane The lower separation distance is the same to prevent unnecessary harmonics.

Description

magnetron

The present invention relates to a magnetron for generating microwaves, and more particularly, to a magnetron formed by chamfering or curving the outer lower end of the top shield to facilitate fastening of the top shield and the filament.

In general, magnetron generates ultra-high frequency by high voltage supplied from outside, and it is 915MHz that is used in magnetron, industrial heating range, continuous wave radar that generates high frequency of 2450MHz used for medical, microwave and other heating. The magnetron generates a high frequency, and the present invention relates to a magnetron used in a microwave oven.

As a general magnetron used in the microwave oven, as shown in FIG. 1, a plurality of (generally, even numbers) forming a cavity resonator to induce a high frequency component inside the anode body 10 formed in a cylindrical shape by a copper pipe or the like. The vanes 13 are arranged at equal intervals in the axial direction, and the anode body 10 and the vanes 13 constitute the anode portion.

On the front end side of the vane 13, the inner and outer pressure equalizing ring 15 and the outer pressure equalizing ring 17 are alternately connected to the vanes 13, respectively, on the upper and lower portions thereof, and on the center axis of the anode body 10, respectively. The working space 23 is formed between the front end of the plurality of vanes 13 and the filament 20.

In addition, in the working space 23, a filament 20 formed of a mixture of tungsten (W) and thorium oxide (ThO ₂ ) and wound in a spiral shape is disposed coaxially with the anode body 10. The filament 20 is heated by an operating current provided from the outside to emit hot electrons.

In addition, a top shield 25 having an outer lower end portion is perpendicular to the upper side of the filament 20, as shown in FIG. 2, in order to prevent radiated hot electrons from radiating upward in a central axis direction. An end shield 27 is fastened to the lower side of the filament 20 to prevent the emitted hot electrons from radiating downward in the central axis direction.

In addition, the first filament electrode 30, which is a molten-density central support body, is welded to the lower end of the top shield 25 at the center of the end shield 27, and the bottom of the end shield 27 is welded to the center of the end shield 27. A molybdenum second filament electrode 33 is welded to the surface.

Here, the first filament electrode 30 and the second filament electrode 33 are connected to the power supply terminal 37 through a through hole formed in the insulating ceramic 35 supporting and fixing the filament 20 of the magnetron. It is a cathode support electrically connected to the first external connection terminal 40 and the second external connection terminal 43 to supply a current to the filament 20, the first filament electrode 30 passes through the central axis of the filament 20 While supporting the top shield 25.

In addition, the upper pole piece 45 and the lower poly 47 which form a magnetic path in both openings of the anode body 10 to uniformly form the magnetic flux in the working space 23 between the filament 20 and the vanes 13. Is welded and fixed, the upper poly 45 and the lower poly 47 are funnel-shaped magnetic bodies.

The upper shield cup 50 and the lower shield cup 53 are tightly welded to the upper and lower portions of the upper poly 45 and the lower poly 47, respectively, and the upper shield cup 50 and the lower shield cup are welded to each other. At the upper and lower parts of 53, the antenna ceramic 55 and the insulating ceramic 35 are closely attached and welded to seal the inside of the anode body 10 in a vacuum state.

In addition, an exhaust pipe 62 made of copper material is bonded to an upper end of the antenna ceramic 55, and an antenna 63 is provided at an inner central portion of the exhaust pipe 62 to output high frequency oscillated in the cavity resonator. The antenna 63 is derived from the vanes 13 and extends axially through the central portion of the upper pole piece 45, and its end is fixed in the exhaust pipe 62.

In addition, the outer surface of the exhaust pipe 62 protects the welding fixing portion of the exhaust pipe 62, prevents sparks generated by electric field concentration, serves as a high frequency antenna, and serves as a window for outputting high frequency to the outside. The antenna ceramic 55 and the antenna cap 57 is covered.

In addition, an upper yoke 60 and a lower yoke 61 are installed outside the anode body 10 to determine the amount of magnetic flux in the anode body 10 so as to connect the returned magnetic flux. Between the 10 and the lower yoke 61, a plurality of aluminum cooling fins 65 are fitted by the clamp member 67 fixed to the anode body 10 and the lower yoke 61, and the magnet A The upper yoke 60 and the lower yoke 61 for forming a path | route together with the 70 and the magnet K 73 are covered.

In the magnetron configured as described above, when an external power source is provided to the first external connection terminal 40 and the second external connection terminal 43 through the power supply terminal 37, the first external connection terminal 40 and the first filament are provided. A closed circuit composed of an electrode 30, a top shield 25, a filament 20, an end shield 27, a second filament electrode 33, and a second external connection terminal 43 is constructed to form a filament 20. The operating current is supplied.

Then, the filament 20 is heated by the operating current provided to the filament 20 to emit hot electrons from the filament 20, thereby forming an electron group by the released hot electrons.

On the other hand, in the working space 23 between the filament 20 and the vanes 13 by the driving voltage applied to the second filament electrode 33 and the anode portion (that is, the anode body 10 and the vane 13). A strong electric field is formed, and the magnetic flux generated by the magnet A 70 and the magnet K 73 is guided along the lower poly 47 to the working space 23 and the upper poly 45 through the working space 23. As it proceeds to, a high magnetic field is formed in the working space 23.

Therefore, the hot electrons emitted from the surface of the hot filament 20 into the working space 23 travel toward the vanes 13 in the horizontal direction by the strong electric field present in the working space 23 and simultaneously in the working space 23. The strong magnetic field is applied to the vanes 13 by the circular motion in a helical direction by the force perpendicular to the direction of travel.

The group of electrons formed by the movement of the electrons interferes with the vanes 13 at a period equal to the inverse of the multiple of the periodic high frequency oscillation frequency, and by this action, the vanes 13 face each other, that is, in the resonator. A resonance component consisting of an capacitance component, which is a capacitance component acting between opposing vanes 13, and an opposing body 10, which connects the opposing vanes 13 and the anode body 10, connects the same, so that the resonance frequency is T-. The high frequency (2450 MHz) determined by 1 is induced from the vanes 13.

Then, the high frequency induced from the vane 13 is transmitted to the exhaust pipe 62 through the antenna 63, provided to the microwave through a wave guide, and then the cavity of the microwave through the dispersing device. The food is cooked by the frictional heat generated when the food molecules in the cavity are vibrated about 2.4 billion times per second.

However, the magnetron according to the related art has an outer lower end portion of the top shield formed at right angles, so that it is difficult to fasten the top shield and the filament, so that the assembly of the top shield and the filament is poor, and thus the image between the filament and the vane is poor. There was a problem in that unnecessary harmonics were generated because the lower separation distance was changed.

Accordingly, the present invention has been made to solve the above problems, and can improve the assemblability of the top shield and the filament in the chamfered or curved shape of the outer lower end of the top shield, as well as between the filament and the vane It is an object of the present invention to provide a magnetron that can prevent unnecessary harmonics by making the upper and lower separation distances the same.

In order to achieve the above object, the magnetron according to the present invention is a magnetron having a top shield fastened to an upper side of the filament to prevent hot electrons emitted from the filament from radiating upward in the direction of the central axis. The outer lower end of the top shield is characterized in that it is formed in a chamfered or curved shape to facilitate.

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

2 is a view showing a top shield of a magnetron according to the related art;

3 is a view showing a top shield of a magnetron according to a first embodiment of the present invention;

4 is a diagram illustrating a top shield of a magnetron according to a second embodiment of the present invention.

Explanation of symbols for the main parts of the drawings

10: bipolar body 13: vane

20,85,95: filament 23: working space

25, 80, 90: top shield 27: end shield

30,83,93: first filament electrode 33: second filament electrode

45: toppolis 47: bottompolis

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view showing a top shield of a magnetron according to a first embodiment of the present invention, as can be seen by comparing the shape of the top shield 25 of FIG. In the shape of the top shield 80 according to the first embodiment of the present invention, the outer lower end portion is formed in a chamfer shape.

4 is a diagram illustrating a top shield of a magnetron according to a second embodiment of the present invention, which is compared with the shape of the top shield 25 of FIG. 2, which shows a conventional top shield of a magnetron. As can be seen, in the shape of the top shield 90 according to the second embodiment of the present invention, the outer lower end portion is formed in a curved shape.

The magnetron according to the present invention having the structure as described above will be described in more detail with reference to FIGS. 3 to 4.

First, in the magnetron according to the first embodiment of the present invention, the first filament electrode 83 is welded to the center of the top shield 80, and the outer lower end of the top shield 80 is formed in a chamfer shape. As the top shield 80 and the filament 85 are easily fastened, and the top shield 80 and the filament 85 are easily fastened, the assemblability of the top shield 80 and the filament 85 is improved. do.

Therefore, since the upper and lower separation distances between the filament 85 and the vanes are the same, unnecessary harmonics are prevented because the upper and lower separation distances between the filaments 85 and the vanes are not the same.

Meanwhile, in the magnetron according to the second embodiment of the present invention, the first filament electrode 93 is welded to the center of the top shield 90, and the outer lower end of the top shield 90 is formed in a curved shape. The fastening of the top shield 90 and the filament 95 is easy, and the fastening of the top shield 90 and the filament 95 facilitates the assembly of the top shield 90 and the filament 95. .

Therefore, since the upper and lower separation distances between the filament 95 and the vanes are the same, unnecessary harmonics are prevented because the upper and lower separation distances between the filaments 95 and the vanes are not the same.

As described above, the magnetron according to the present invention may not only improve the assemblability of the top shield and the filament by forming the outer lower end in a chamfered or curved shape, but also have the same upper and lower separation distances between the filament and the vane. By doing so, it is possible to prevent unnecessary harmonics in advance.

Claims (2)

In a magnetron having a top shield fastened to an upper side of the filament to prevent hot electrons emitted from the filament from radiating upward in the direction of the central axis, the outer lower end of the top shield has a chamfered shape to facilitate fastening with the filament. Magnetron, characterized in that formed. In the magnetron having the top shield fastened to the upper side of the filament to prevent the hot electrons emitted from the filament to radiate upward in the direction of the central axis, the outer lower end of the top shield in a curved shape to facilitate fastening with the filament Magnetron, characterized in that formed.