KR19980011651U - Magnetron's And Shield Structure - Google Patents

Abstract

The present invention relates to the end shield structure of the magnetron, wherein the cross-sectional area of the upper portion of the lower end shield is extended to a predetermined width between the anode vane and the lower pole piece, and a negative voltage is applied to the lower end shield to release the hot electrons into the working space. When a group of electrons due to spiral approach near the lower pole piece, it is applied to the lower end shield that extends in cross-section between the anode vane and the lower poly, causing phosphorus to generate a repulsive force in the electron group due to negative voltage. Therefore, since the collision between the electron group and the lower pole piece in the working space is prevented, damage to the lower pole piece due to the collision with the electron group is prevented.

Description

Magnetron End Shield Structure

The present invention relates to a magnetron, and more particularly, to an end shield structure of a magnetron suitable for preventing the lower pole piece from being damaged by an electron group in the working space.

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

On the other hand, Figure 1 is a cross-sectional view showing the structure of a conventional conventional magnetron.

As can be seen from the same figure, a plurality of (generally even) anode vanes 8 which form a cavity resonator to induce high frequency components inside the anode body 6 formed in a cylindrical shape by copper pipes or the like. It is arrange | positioned at equal intervals toward this axial direction, and the anode part is comprised by such a cathode body 6 and the anode vane 8.

In order to change the capacitance to obtain a uniform resonant frequency, inner and outer equalization rings 8a and 8b are alternately connected to the anode vanes 8 at upper and lower ends thereof, respectively, on the tip side of the anode vanes 8, respectively. On the central axis of the positive electrode body 6, a working space 10 is formed between the front ends of the plurality of positive electrode vanes 8 and the filaments 12.

In addition, in the working space 10, a filament 12 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 6. 12 is heated by an operating current provided from the outside to emit hot electrons.

On the other hand, the upper and lower end shields 14 and 16 are fixed to both ends of the filament 12 to prevent radiated hot electrons from radiating in the central axis direction. Molybdenum is formed at the center of the lower end shield 16. The first filament electrode 20, which is a central support of the welding, is welded and fixed to the lower end of the upper end shield 14 through a through hole formed in the center, and a second filament electrode made of molybdenum is formed on the bottom surface of the lower end shield 16. 22) is welded.

Here, the first and second external filament electrodes 20 and 22 are connected to the power supply terminals 28 and 30 through through holes formed in the insulating ceramic 18 supporting the cathode of the magnetron. A cathode support is electrically connected to the connection terminals 24 and 26 to supply current to the filament 12. The first filament electrode 20 supports the upper end shield 14 while passing through the central axis of the filament 12. do.

In addition, both sides of the anode body 6 are welded to the upper and lower polypolises 32 and 34 which form a magnetic path to uniformly form the magnetic flux in the working space 10 between the filament 12 and the anode vane 8. The upper and lower polypolises 32 and 34 are fixed, funnel-shaped magnetic bodies.

In addition, upper and lower shield cups 36 and 38 are adhered and welded to upper and lower portions of the upper and lower polices 32 and 34, respectively, and anode bodies 6 are disposed on upper and lower shield cups 36 and 38, respectively. The antenna ceramic 40 and the insulating ceramic 18 are brought into close contact with each other in order to seal the inside of the vacuum chamber under vacuum.

In addition, a cylindrical antenna ceramic 40 for insulating the antenna cap 42 to be described later is bonded to the upper opening end of the upper shield cup 36 constituting the output portion of the magnetron, and an upper end portion of the antenna ceramic 40 is connected. The exhaust pipe 44, which is a copper material, is bonded thereto, and an antenna 46 is provided at the inner central portion of the exhaust pipe 44 to output high frequency oscillated in the cavity resonator, and the antenna 46 has a bipolar vane 8. Derived from, it is penetrated through the central portion of the upper pole piece 32 and extends axially, the end is fixed in the exhaust pipe (44).

In addition, the outer surface of the exhaust pipe 44 protects the welded portion of the exhaust pipe 44, 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. An antenna ceramic 40 and an antenna cap 42 are covered.

The operation process of the magnetron made of the above-described members is as follows.

First, when an external power source is provided to the first and second external connection terminals 24 and 26 through the power terminals 28 and 30, the first external connection terminal 24, the first filament electrode 20, and the upper end are provided. A closed circuit composed of the shield 14, the filament 12, the lower end shield 16, the second filament electrode 22, and the second external connection terminal 26 is configured to supply an operating current to the filament 12.

Then, the filament 12 is heated by the operating current provided to the filament 12 to emit hot electrons from the filament 12, thereby forming an electron group by the released hot electrons.

At this time, in the working space 10 between the filament 12 and the anode vane 8 by the driving voltage applied to the second filament electrode 22 and the anode portion (that is, the anode body 6 and the anode vane 8). The strong electric field is formed, the magnetic field generated by the magnet A (2) and the magnet K (4) is guided along the lower pole piece 34 toward the working space (10) to the upper pole piece through the working space (10) Proceeding to 32, a high magnetic field is formed in the working space 10.

Therefore, the electron group formed by the hot electrons emitted from the filament 12 into the working space 10 is formed by the strong electric field and the high magnetic field formed in the working space 10, and thus the anode portion (the anode body 6 and the anode vane 8). It proceeds in a spiral rotational motion in the direction of), and this movement of the electron group is performed in all spaces of the working space 10.

Accordingly, the electron group formed of hot electrons is repeatedly moved toward the anode portion (the anode body 6 and the anode vane 8) according to the structural resonance circuit between the anode vane 8 and the cavity resonator. A high frequency of 2450 MHz, which is a resonance frequency corresponding to the speed of rotation, is induced from the anode vanes 8.

Then, the high frequency (2450 MHz) induced from the anode vanes 8 is transmitted to the exhaust pipe 44 through the antenna 46, provided to the microwave through the wave guide, and then electrons through the dispersing device. It is provided to the cavity of the stove to cook the food by the frictional heat generated by the molecules in the cavity vibrating about 2.4 billion times per second.

On the other hand, Figure 2 is a view showing the end shield structure of a conventional conventional magnetron.

1 and 2, when the electron group caused by the hot electrons emitted from the filament 12 reaches the point A during the spiral motion by the electric field and the magnetic field formed in the working space 10, It is attracted strongly by the lower pole piece 34, and eventually the electron group at the point A strikes the lower pole piece 34.

Due to the collision between the electron group and the lower pole piece 34, heat is generated in the lower pole piece 34, so that the lower pole piece 34 melts.

Accordingly, the present invention is conceived in view of the problems of the prior art as described above, and the end shield of the magnetron which can prevent the collision between the electron group and the lower pole piece in the working space by widening the cross-sectional area of the end shield in the magnetron. The purpose is to provide a structure.

The present invention to achieve the above object,

1 shows a cross-sectional view of a typical typical magnetron.

2 is a view illustrating an end shield structure of a conventional magnetron according to the related art.

3 is a view showing the end shield structure of the magnetron according to a preferred embodiment of the present invention

Explanation of symbols on the main parts of the drawings

2: Magnet A: Magnet K

6: anode body 8: anode vane

10: working space 12: filament

(14, 16): End shield 18: Insulated ceramic

(20, 22): filament electrode (24, 26): external connection terminal

(28, 30): Power stage (32, 34): Pole piece

(36, 38): Shield Cup 40: Antenna Ceramic

42: antenna cap 44: exhaust pipe

46: antenna

The above and other objects and various advantages of the present invention will become more apparent through the preferred embodiments of the present invention described below with reference to the accompanying drawings by those skilled in the art.

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

3 is a view showing the end shield structure of the magnetron according to a preferred embodiment of the present invention.

As can be seen with reference to Figure 3, the cross-sectional area of the upper side of the lower end shield 16 is extended between the anode vane 8 and the lower pole piece 34 is mounted, the negative voltage is applied to the lower end shield 16 It is authorized.

Therefore, when the electron group due to the hot electrons emitted to the working space 10 reaches the point A during the spiral motion, the cross-section that extends in cross section between the anode vane 8 and the lower pole piece 34 The negative force applied to the end shield 16 generates a repulsive force in the electron group.

Therefore, by using the present invention, since the collision between the electron group and the lower pole piece 34 in the working space 10 is prevented, the effect of preventing damage to the lower pole piece 34 due to the collision with the electron group. There is.

Claims (1)

A plurality of anode vanes, each of which is heated by an operating current to emit hot electrons, and forms a cavity resonator, each of which is formed at equal intervals toward the center axis direction, and the plurality of anode vanes are mounted therein; And upper and lower pole pieces forming a magnetic path to uniformly form magnetic flux in the working space between the filament and the plurality of anode vanes, the hot electrons emitted from the filament. A magnetron comprising an upper and a lower end shield for preventing radiation, wherein the lower end shield has an upper side extending in a predetermined width in a direction toward the anode vane and the lower pole piece. rescue.