KR980009628U - magnetron - Google Patents

Abstract

The present invention relates to a magnetron having high efficiency while maintaining stable operating characteristics, and includes a filament 17 for emitting hot electrons, magnets 41 and 43 for generating magnetic flux, and generated in the magnets 41 and 43. Pole pieces 33 and 35 for inducing a magnetic flux, yokes 53 and 55 for connecting the magnetic flux returned from the magnets 41 and 43, and a plurality of vanes 15 are arranged to generate microwaves. In the magnetron comprising an anode cylinder 13, a working space 12 formed between the vanes 15 and the filaments 17, and filament electrodes 23 and 25 for supplying power to the filaments 17, The magnet 43 is fixed to the magnet 43 so that the magnetic flux formed in the working space 12 is suppressed to reduce the amount of magnetic flux of the magnets 41 and 43. By reducing the amount of magnetic flux, a constant The amount of magnets 41 and 43 necessary to supply the magnetic flux can be reduced.

Description

magnetron

1 is a longitudinal sectional view of a conventional magnetron,

Figure 2 is a longitudinal cross-sectional view of the magnetron according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

12: working space 13: anode cylinder 15: vane

17: filament 20: upper shield hat 21: lower shield hat

23: first filament electrode 25: second filament electrode

29, 31: External connection terminal 33, 35: Upper and lower pole piece

37, 39: upper and lower shield cup 41, 43: magnet

44: magneto-government 45: antenna ceramic

47: exhaust pipe 49: antenna

51 antenna cap 53,55: upper and lower yokes

57: cooling fin

The present invention relates to a magnetron having high efficiency while maintaining stable operating characteristics.

In general, as shown in FIG. 1, a conventional magnetron includes a plurality of (even) pieces of a plurality of resonant cavities that form a plurality of resonant cavities so as to induce high frequency components inside a cylindrical body 13 formed in a cylindrical shape by a copper pipe or the like. The vanes 15 are arranged at equal intervals in the axial direction, and the anode cylinder 13 and the vanes 15 constitute the anode portion.

In addition, near the distal end side of the vane 15, inner and outer regulating rings 15a and 15b are connected to each other in the vane 15 so as to obtain a constant resonance frequency by varying the capacitance in the upper and lower portions, respectively. A working space 12 is formed between the front end portions of the plurality of vanes 15 and the filaments 17 near the central axis of the anode cylinder 13.

In the working space 12, a filament heater 17 (hereinafter referred to as a filament) wound in a spiral shape by mixing and sintering tungsten (W) and thorium oxide (Th02) so as to generate high heat is provided with the anode body 13. It is arranged coaxially.

Upper and lower shield hats 20 and 21 are fixed to both ends of the filament 17 so as to prevent radiation of hot electrons, which do not contribute to oscillation, from being radiated in the central axis direction. The first filament electrode 23, which is a central support made of molybdenum, is welded to the lower end of the upper shield hat 20 through a through hole formed in the center portion, and molybdenum is formed on the bottom surface of the lower shield hat 21 at the center portion. The second second filament electrode 25 is welded and fixed.

The first filament electrode 23 supports the upper shield hat 20 while passing through the central axis of the filament 17, and the first and second filament electrodes 23 and 25 are cathodes of the magnetron. Is electrically connected to the first and second external connection terminals 29 and 31, which are connected to a power supply terminal (not shown), through a through hole formed in the insulating ceramic 27 supporting and securing the current to the filament 17. It is a cathode support.

In addition, the top and bottom of the funnel shape, which is a magnetic body that forms a magnetic flux on both side openings of the anode cylinder 13 to form a magnetic flux uniformly in the working space 12 formed by the filaments 17 and the vanes 15. The pole pieces 33 and 35 are welded and welded.

Upper and lower shield cups 37 and 39 are hermetically welded to upper and lower portions of the upper and lower pole pieces 33 and 35, respectively, and upper and lower portions of the upper and lower shield cups 37 and 39, respectively. The antenna ceramic 45 and the insulating ceramic 27 are hermetically welded to seal the inside of the anode cylinder 13 with a vacuum.

In addition, a cylindrical antenna ceramic 45 for insulating the antenna cap, which will be described later, is joined to the upper opening end of the upper shield cup 37 constituting the output of the magnetron, and to the upper end of the antenna ceramic 45. An exhaust pipe 47 made of copper is joined, and near the inner center portion of the exhaust pipe 47 is an antenna 49 derived from the vane 15 so as to output a high frequency oscillated in the resonance cavity. The end of the antenna 49 is fixed in the exhaust pipe 47 while extending axially through the through hole.

In addition, the outer surface of the exhaust pipe 47 protects the welded and fixed portion of the exhaust pipe 47 as well as prevents sparking due to electric field concentration and acts as a high frequency antenna, and simultaneously emits a high frequency output to the outside. The antenna ceramic 45 and the antenna cap 51 are placed on it.

In the magnetron configured as described above, first, when power is applied through the first and second external connection terminals 29 and 31, the first external connection terminal 29 → the first filament electrode 23 → the upper shield. The hat 20 is formed by the filament 17, the lower shield hat 21, the second filament electrode 25, the second external connection terminal 31, and a closed circuit is supplied to the filament 17. Heated.

When the filament 17 is heated to a high temperature, it begins to emit hot electrons into the working space 12.

At this time, a strong electric field is formed in the working space 12 between the vane 15 and the outer surface of the filament 17 by the driving voltage applied to the second filament electrode 25 and the anode. Starting at (15) it leads to filament (17).

On the other hand, the magnetic flux generated from the magnet (not shown) is guided toward the working space 12 along the lower pole piece 35, and proceeds to the upper pole piece 33 through the working space 12 to form a magnetic path to form the working space ( 12) High magnetic flux density is formed.

Therefore, the hot electrons emitted from the surface of the hot filament 17 into the working space 12 travel toward the vane 15 or the anode body 13 by the strong electric field present in the working space 12 and at the same time the working space ( 12) It receives a force perpendicular to the direction of travel due to the strong magnetic flux density present in the circle and moves in a circular direction as the electrons advance toward the anode.

The movement of the electrons is made in all the working spaces 12, and the electrons form a group of electrons according to the structural resonance circuit of the vanes 15, and the vanes 15 are repeatedly carried out to the vanes 15, which are high potentials. ) Generates a 2450 MHz (fundamental wave) microwave, which is a resonant frequency corresponding to the speed at which the electron group rotates.

However, in the conventional magnetron in which the magnetic path is formed in the structure as described above, since the material of the magnet fixing part for fixing the magnet is a ferromagnetic material, the magnetic flux formed in the working space 12 leaks through the magnet fixing part and thus the working space 12 Since the magnetic flux density is lowered, there is a problem that a large amount of magnet is required to compensate for this.

Therefore, the present invention has been made to solve the above problems, and the object of the present invention is to supply the magnetic flux of a certain intensity in the working space by reducing the leakage flux by using a non-magnetic material of the magnet fixing part made of stainless steel It is to provide a magnetron that can reduce the amount of magnet needed to.

In order to achieve the above object, the magnetron according to the present invention is a filament for emitting hot electrons, a magnet for generating magnetic flux to maintain rotational motion by deflecting electrons emitted from the filament, and a magnet to induce magnetic flux generated in the magnet. A pole body forming a pole, a yoke for determining the amount of magnetic flux to connect the magnetic flux returned from the magnet, an anode body having a plurality of vanes arranged to generate microwaves by surrounding the filament from the outside, and the vanes and the filaments A magnetron comprising a working space formed therebetween, an antenna for inducing microwaves generated in the anode cylinder, and a filament electrode for supplying power to the filament, wherein the magnet suppresses leakage of magnetic flux formed in the working space. To reduce the magnetic flux of the magnet It is characterized in that the magnetism of the nonmagnetic material is fixed.

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

The same reference numerals are attached to the same parts as in the conventional configuration.

As shown in Fig. 2, inside the anode cylinder 13 formed in a cylindrical shape by a copper pipe or the like, a plurality of (even) vanes 15 forming a plurality of resonant cavities to induce high frequency components are axially oriented. It is arrange | positioned at equal intervals toward and the anode part is comprised by these anode cylinder 13 and the vane 15. As shown in FIG.

In addition, a working space 12 is formed between the front end portions of the plurality of vanes 15 and the filaments 17 near the central axis of the anode cylinder 13, and generates high heat in the working space 12. A filament heater 17 (hereinafter referred to as a filament) wound and spirally wound by mixing and sintering tungsten (W) and thorium oxide (ThO 2) is disposed coaxially with the anode cylinder 13.

Upper and lower shield hats 20 and 21 are fixed to both ends of the filament 17 so as to prevent radiation of hot electrons, which do not contribute to oscillation, from being radiated in the central axis direction. In the center part, the first filament electrode 23, which is a central support body made of phybdenum, is welded and fixed to the lower end of the upper shield hat 20 through a through hole formed in the center part, and on the bottom surface of the lower shield hat 21. The second filament electrode 25 made of molybdenum is welded and fixed.

The first filament electrode 23 supports the upper shield hat 20 while passing through the central axis of the filament 17, and the first and second filament electrodes 23 and 25 support and fix the cathode of the magnetron. Electrically connected to the first and second external connection terminals 29 and 31 connected to the power supply terminals 30b and 32b through the through holes formed in the 27, the current is supplied to the filament 17.

One end of the choke coils 30 and 32 is electrically connected to the first and second external connection terminals 29 and 31, and the other end of the choke coils 30 and 32 is formed on the sidewall of the box filter. The ferrites 30a and 32a, which absorb noise, are inserted and fixed in the choke coils 30 and 32 in the choke coils 30 and 32. .

In addition, the top and bottom of the funnel shape, which is a magnetic body that forms a magnetic flux on both side openings of the anode cylinder 13 to form a magnetic flux uniformly in the working space 12 formed by the filaments 17 and the vanes 15. The pole pieces 33 and 35 are welded together.

Upper and lower seal cups 37 and 39 are hermetically welded to upper and lower portions of the upper and lower pole pieces 33 and 35, respectively, and the anodes are formed on outer surfaces of the upper and lower shield cups 37 and 39, respectively. Ring-shaped upper and lower magnets 41 and 43 are arranged in the cylinder 13 to maintain a constant magnetic field distribution. The lower magnet 43 is fixed to one side of the lower magnet 43 and leaks at the same time. In order to suppress the magnetic flux, a magnet fixing part 44 made of a non-magnetic material of stainless steel is fixed.

In addition, the outer and outer yoke (53, 55) for determining the amount of magnetic flux in the anode cylinder 13 is connected to the outside of the anode cylinder 13, the anode cylinder 13 And a plurality of aluminum cooling fins 57 are disposed between the upper yoke and the lower yoke 55 by a clamp member 55a fixed to the anode cylinder 13 and the lower yoke 55. The upper and lower yokes 53 and 55 for forming a porcelain are formed together with the 41 and 43.

Hereinafter, the effect of the magnetron configured as described above will be described.

First, when power is applied through the first and second external connection terminals 29 and 31, the first external connection terminal 29 → the first filament electrode 23 → the upper shield hat 20 → the filament 17 The closed circuit is formed by the lower shield hat 21, the second filament electrode 25, and the second external connection terminal 31, and an operating current is supplied to the filament 17 to be heated.

When the filament 17 is heated to a high temperature, it begins to emit hot electrons into the working space 12.

At this time, a strong electric field is formed in the working space 12 between the vane 15 and the outer surface of the filament 17 by the driving voltage applied to the second filament electrode 25 and the anode. Starting at (15) it leads to filament (17).

On the other hand, the magnetic flux generated from the two upper and lower magnets (41, 43) is guided toward the working space 12 along the lower pole piece 35, the guided magnetic flux through the working space 12, the upper pole piece ( 33, the working space 12 is distributed in a magnetic circuit consisting of the upper yoke 53, the lower yoke 55, the upper pole piece 33, the lower pole piece 35, and the working space 12. High magnetic flux density is formed inside.

At this time, the magnetic flux density of a certain intensity must be formed in the working space 12 to supply stable microwave energy during power generation, as well as increase efficiency.

Therefore, in the present invention, the magnetic flux formed in the working space 12 is leaked by changing the material of the magnet fixing part 44 from the existing ferromagnetic material to the nonmagnetic material of stainless steel so as to suppress leakage of the magnetic flux through the magnet fixing part 44. By reducing the amount of magnetic flux, it is possible to supply a magnetic flux density of a certain intensity into the working space 12 while minimizing the amount of magnetic flux of the magnets 41 and 43 required to supply the magnetic flux to the working space 12.

Therefore, the hot electrons emitted from the surface of the hot filament 17 into the working space 12 travel toward the vane 15 or the anode body 13 by the strong electric field present in the working space 12 and at the same time the working space ( 12) It moves in a circular direction as it progresses toward the anode by receiving a force perpendicular to the direction of travel by the uniform magnetic flux density present in it.

All of the movement of the electrons is made in the working space 12, and the electrons form a group of electrons along the structural resonance circuit of the vane 15, and the vanes 15 are repeatedly carried out to the high potential vane 15. Generates a 2450 MHz band (fundamental wave) microwave, which is a resonant frequency corresponding to the speed at which the electron group rotates. When 4KV of operating voltage Va is applied to both ends of the filament 17 and the vane 15, the magnetron It has a high efficiency of more than 70%.

On the other hand, in one embodiment of the present invention has been described by taking the material of the magnet fixing portion 44 as a non-magnetic material to suppress the leakage flux in the working space 12, by reducing the height of the magnet fixing portion 44 The leakage flux can also be suppressed.

According to the magnetron according to the present invention as described above, by using the magnetic material of the stainless steel non-magnetic material of the stainless steel to reduce the amount of magnetic flux leakage can reduce the amount of magnet required to supply a constant magnetic flux in the working space It has an outstanding effect.

Claims (2)

Filaments 17 for emitting hot electrons, magnets 41 and 43 for generating magnetic flux to maintain rotational motion by deflecting electrons emitted from the filaments 17, and magnetic fluxes generated in the magnets 41 and 43 The yoke (53, 55) and the filament (17) to determine the amount of magnetic flux to connect the magnetic flux returning from the magnet (41, 43) and the pole pieces (33, 35) to form a magnetic path to guide the In the anode cylinder 13, a plurality of vanes 15 are arranged so as to generate microwaves, the working space 12 formed between the vanes 15 and the filaments 17, and in the anode cylinder 13 In the magnetron composed of an antenna 49 for inducing generated microwaves and filament electrodes 23 and 25 for supplying power to the filament 17, the magnet 43 is formed in the working space 12. The magnets 41 and 43 by suppressing leakage of magnetic flux To reduce the magnetic flux magnetron, it characterized in that the magnet fixing part (44) of non-magnetic material is fixed. The magnetron according to claim 1, wherein the magnet fixing part (44) is fixed to one side of the lower magnet (43). ※ Note: This is to be disclosed based on the first application.