KR19990010071A - magnetron - Google Patents

Abstract

The present invention relates to a magnetron, and a choke 90 is formed on the top surface of the insulating ceramic 35 to block energy flowing out through the cathode, and passes through the filament 20. And a first negative electrode terminal 95 for connecting the first negative electrode 30 to an external power supply terminal (not shown) are electrically connected by the choke 90 to allow energy to flow out through the negative electrode. At the same time blocking the manufacturing cost is effective.

Description

magnetron

The present invention relates to a magnetron that oscillates microwaves by applying a high voltage, and more particularly, to a magnetron that can reduce manufacturing energy while attenuating microwave energy flowing out through the cathode terminal of the magnetron.

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

Conventional magnetrons used in the microwave oven have a plurality of (generally, forming cavity resonators so as to induce high frequency components inside the anode body 10 formed in a cylindrical shape by a copper pipe or the like as shown in FIG. Even-numbered 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 parts 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, which is 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.

On the other hand, the upper shield hat 25 and the lower shield hat 27 is fixed to both ends of the filament 20 in order to prevent the emitted hot electrons radiate in the direction of the central axis, respectively, of the lower shield hat 27 In the center portion, a first cathode 30, which is a central support made of molybdenum, is welded and fixed to the lower end of the upper shield hat 25 through a through hole formed in the middle portion, and the bottom surface of the lower shield hat 27 is made of molybdenum. 2 cathodes 33 are welded together.

Here, the first negative electrode 30 and the second negative 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. The cathode support is electrically connected to the terminal 40 and the second cathode terminal 43 to supply current to the filament 20. The first cathode 30 penetrates the central axis of the filament 20 while the upper shield hat ( 25).

In addition, the upper pole piece 45 and the lower pole piece 47 which form a magnetic path at both side 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.

In addition, upper and lower shield cups 50 and lower shield cups 53 are adhered to and welded to upper and lower portions of the upper pole piece 45 and the lower pole piece 47, respectively. In order to seal the inside of the anode body 10 in a vacuum state, upper and lower portions of the shield cup 53 are in contact with and welded to the ceramic ceramic 55 and the insulating ceramic 35.

In addition, a cylindrical antenna ceramic 55 for insulating the antenna cap 57 to be described later is joined to the upper opening end of the upper shield cup 50 constituting the output portion of the magnetron, and an upper end portion of the antenna ceramic 55 is joined. The exhaust pipe 62, which is a copper material, is joined to the inner central portion of the exhaust pipe 62, and an antenna 63 is provided to output the high frequency oscillated in the cavity resonator. Derived from, it is penetrated through the central portion of the upper pole piece 45 extends axially and the 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.

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 negative electrode terminal 40 and the first negative electrode ( 30), a closed circuit composed of the upper shield hat 25, the filament 20, the lower shield hat 27, the second cathode 33 and the second cathode terminal 43 is configured to operate the filament 20 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.

At this time, the driving voltage applied to the second cathode 33 and the anode portion (that is, the anode body 10 and the vane 13) is strong in the working space 23 between the filament 20 and the vane 13. An electric field is formed, and the magnetic field 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 the upper pole piece 45 through the working space 23. As it proceeds to the high magnetic field is formed in the working space (23).

Accordingly, 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 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. The capacitance component, which is the capacitance 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 resonance circuit on the circuit, and the parallel resonance circuit The high frequency (2450 MHz) determined by is derived from the vane 13.

Then, the high frequency (2450 MHz) induced from the vane 13 is transmitted to the exhaust pipe 62 through the antenna 63, provided to the electron lens through the wave guide, and then through the dispersing apparatus. It is provided as a cavity, and the food is cooked by the frictional heat generated when the molecules in the cavity vibrate about 2.4 billion times per second.

In the microwave oven configured as described above, as shown in FIG. 2, a choke ring 80 is mounted on the first cathode 30, and the choke ring 80 is connected to the first cathode 30 as described above. 30) to attenuate the fundamental wave and each harmonic flowing out through the first cathode 30 to the outside.

That is, when magnetron oscillation, energy of 2 to 3% is discharged to the outside through the first cathode 30. Since the energy adversely affects the magnetron efficiency and other characteristics, the choke ring is used as described above to attenuate it. It is attenuated.

However, the conventional magnetron that attenuates energy flowing out through the cathode by using the choke ring as described above has a problem in that the work process is difficult and the manufacturing cost is large by using the choke ring.

Accordingly, the present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a magnetron having low manufacturing cost while blocking energy flowing out through the cathode.

The magnetron according to the present invention for achieving this object, a magnetron comprising a cathode for supplying a current to the filament to emit hot electrons, and an insulating ceramic for sealing the interior of the positive electrode body in the center of the filament in a vacuum state To

A choke is formed on the upper surface of the insulating ceramic, and a negative electrode penetrating the filament and a negative electrode terminal for connecting the negative electrode to the outside are electrically connected by the choke, while the length of the choke is of a wavelength to be attenuated. It is characterized by being 1/2.

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

2 is a cross-sectional view showing the main parts of the magnetron shown in FIG. 1;

3 is a cross-sectional view showing the main portion of the magnetron according to the present invention.

Explanation of symbols for main parts of the drawings

20: filament 30: first cathode

33: second cathode 35: insulating ceramic

90: choke 95: first negative terminal

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

3 is a cross-sectional view of the main portion of the magnetron according to the present invention. In the magnetron according to the present invention, the lower shield hat 27 is fixed to the lower end of the filament 20 to prevent radiated hot electrons from radiating in the direction of the central axis. In the center of the lower shield hat 27, the first cathode 30, which is a central support made of molybdenum, penetrates the through hole formed in the center, and the second cathode of molybdenum is formed on the bottom of the lower shield hat 27. 33) is welded.

In addition, a lower pole piece 47 for forming a magnetic path is uniformly welded to the lower opening of the anode body 10 so as to uniformly form magnetic flux in the working space of the filament 20 and the vanes (not shown). The pole piece 47 is a funnel-shaped magnetic body.

In addition, a lower shield cup 53 is closely attached to the lower portion of the lower pole piece 47 to be welded thereto, and a lower portion of the lower shield cup 53 is used to seal the inside of the anode body 10 in a vacuum state. The insulating ceramic 35 is in close contact with each other and welded thereto.

In addition, a choke 90 is formed on an upper surface of the insulating ceramic 35, and the first negative electrode 30 and the first negative electrode 30 penetrating the filament 20 are external power terminals (not shown). ) Is connected to the first negative electrode terminal (95) by the choke (90).

In this case, the choke 90 is formed by forming a slot on the top surface of the insulating ceramic 35 and coating the slot with a metal film. The length of the choke 90 is a half of a wavelength to be attenuated. desirable.

The operation and effects of the magnetron according to the present invention made as described above will be described in detail.

The magnetron of the present invention forms a slot on the top surface of the insulating ceramic 35, forms a choke 90 by coating a metal film on the slot, and then passes through the first negative electrode terminal 95 through a through hole formed in the insulating ceramic 35. ) Is electrically connected to the choke 90.

In addition, the first cathode 30 is electrically connected to the choke 90 to penetrate through the filament 20, so that the first cathode 30 and the first cathode 30 are externally connected to power terminals (not shown). The first negative electrode terminal 95 for connecting to the axle) is electrically connected by the choke 90.

At this time, the length of the choke 90 is 1/2 of the wavelength to be attenuated, and blocks the energy flowing out through the cathode.

In addition, as the choke 90 is integrally formed with the insulating ceramic 35 as described above, the magnetron manufacturing process is easy and the manufacturing cost is reduced.

As described above, according to the present invention, a choke is formed on the upper surface of the insulating ceramic to block the energy flowing out through the cathode and at the same time reduce the manufacturing cost.

Claims (2)

In a magnetron comprising a cathode for supplying a current to the filament to emit hot electrons, and an insulating ceramic for sealing the interior of the positive electrode body in the center of the filament in a vacuum state, A choke is formed on the upper surface of the insulating ceramic, and a negative electrode penetrating the filament and a negative electrode terminal for connecting the negative electrode to the outside are electrically connected by the choke, while the length of the choke is of a wavelength to be attenuated. Magnetron, characterized in that 1/2. The method of claim 1, The choke is a magnetron, characterized in that the slot is formed on the upper surface of the insulating ceramic, the metal film is formed in the slot.