KR19990004563U - magnetron - Google Patents

Abstract

The present invention relates to a magnetron, by forming the inner upper end of the end shield in a chamfered or curved shape to facilitate fastening with the filament, it is possible to improve the assembly of the end shield and the filament. The upper and lower separation distances between the filaments and the vanes are 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 to chamfer or bend the inner upper end of the end shield to improve the assemblability of the end shield and the filament.

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

A general magnetron used in the microwave oven has a plurality of (generally, even numbers) forming a cavity resonator so as to induce a high frequency component inside the anode body 10 formed in a cylindrical shape by a copper pipe or the like as shown in FIG. 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.

The upper and lower parts of the vane 13 are alternately connected to the inner pressure equalizing ring 15 and the outer pressure equalizing ring 17 to the vanes 13, respectively, and are arranged on the center axis of the anode body 10. 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, the top shield 25 is fastened to prevent the emitted hot electrons from radiating upward in the direction of the central axis in the upper side of the filament 20, and the emitted hot electrons in the lower side of the filament 20 in the central axis. In order to prevent radiation to the lower side of the direction, as shown in FIG. 2, the end shield 27 whose inner upper end part is a rectangular shape is fastened.

In addition, the first filament electrode 30, which is a molten-density central support, 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 and fixed. 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. 1 is a cathode support electrically connected to the external connection terminal 40 and the second external connection terminal 43 to supply the current to the filament 20, the first filament electrode 30 penetrates the central axis of the filament 20 While supporting the top shield 25.

In addition, the upper pole piece 45 and the lower pole piece 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 pole piece 45 and the lower pole piece 47 are funnel-shaped magnetic bodies.

The upper shield cup 50 and the lower shield cup 53 are adhered to each other by welding to the upper and lower portions of the upper pole piece 45 and the lower pole piece 47, respectively, and the upper shield cup 50 and the lower shield are welded to each other. In order to seal the inside of the anode body 10 in a vacuum state, the ceramic ceramic 55 and the insulating ceramic 35 are closely attached and welded to the upper and lower portions of the cup 53.

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 welded 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.

The magnetron configured as described above has the first external connection terminal 40 and the first filament electrode 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. And a closed circuit composed of the top shield 25, the filament 20, the end shield 27, the second filament electrode 33, and the second external connection terminal 43, so that the filament 20 has an 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 pole piece 47 toward the working space 23 and through the working space 23 to the upper pole piece ( Proceeding to 45, 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 to the vane 13 in the horizontal direction by the strong electric field present in the working space 23 and are present in the working space 23. It receives a force perpendicular to the direction of travel by a strong magnetic field to reach the vanes 13 in a circular motion in a spiral.

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. The capacitance component, which is the capacitance component acting between the opposing vanes 13, and the inductance component composed of the opposing vanes 13 and the anode body 10 connecting them, constitute a parallel resonant circuit on the circuit, so that the resonance frequency is increased. The high frequency (2450 MHz) determined by is derived from the vane 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 inner upper end portion of the end shield formed at a right angle so that it is difficult to fasten the end shield and the filament, so that the assembly of the end shield and the filament is poor. There was a problem that unnecessary harmonics were generated because the lower separation distance was changed.

Therefore, the present invention is devised to solve the above problems, and by forming the inner upper end of the end shield in a chamfered or curved shape, it is possible to improve the assemblability of the end shield and the filament. It is an object of the present invention to provide a magnetron that can prevent unnecessary harmonics in advance by making the upper and lower separation distances between the filaments and the vanes the same.

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

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

2 is a view illustrating an end shield of a magnetron according to the related art;

3 is a view showing the end shield of the magnetron according to the first embodiment of the present invention,

4 is a view showing the end shield of the magnetron according to a second embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

10: bipolar body 13: vane

20, 85, 95: filament 23: working space

25: Top shield 27, 80, 90: End shield

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

45: upper pole piece 47: lower pole piece

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

FIG. 3 is a view illustrating an end shield of a magnetron according to a first embodiment of the present invention, as compared with the shape of the end shield 27 of FIG. In the shape of the end shield 80 according to the first embodiment of the present invention, the inner upper end portion is formed in a chamfer shape.

On the other hand, Figure 4 is a view showing the end shield of the magnetron according to the second embodiment of the present invention, and compared with the shape of the end shield 27 in Figure 2 showing the end shield of the magnetron according to the prior art As can be seen, the shape of the end shield 90 according to the second embodiment of the present invention is formed in the upper end portion is curved.

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 and fixed to the center portion of the end shield 80, and the inner upper end of the end shield 80 is formed in a chamfer shape. As the fastening with the filament 85 is easy, and as the fastening of the end shield 80 and the filament 85 is easy, the assembling property of the end shield 80 and the filament 85 is improved.

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 and fixed to the center portion of the end shield 90, and the inner upper end of the end shield 90 is formed in a curved shape. As the fastening with the filament 95 is easy, and as the fastening of the end shield 90 and the filament 95 is easy, the assembling property of the end shield 90 and the filament 95 is improved.

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 end shield and the filament by forming the inner upper end of the end shield in a chamfered or curved shape. By equalizing the upper and lower separation distance between the filament and the vane, there is an effect that can prevent unnecessary harmonics in advance.

Claims (2)

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