KR0120633Y1 - Output terminal structure of magnetron - Google Patents

Abstract

The present invention relates to a magnetron used in a microwave heating device such as a microwave oven, in particular, by forming a resonance structure of 12.25 GHz between two pairs of first and second metal rings joined inside a metal tube that is an output of the magnetron. The structure of the output portion of the magnetron to prevent leakage of the fifth harmonic, the filament (5) for emitting hot electrons and the plurality of vanes to surround the filament (5) from the outside to form a resonant cavity near the center Fixed to the opening of the anode cylinder (1) having the arrangement (3) and the anode cylinder (1) to form a magnetic path so as to uniformly converge in the working space formed by the filaments (5) and the vanes (3). Metal pipes fixed to upper and lower portions of the funnel-shaped first and second magnetic pole pieces 15 and 17 and the first and second magnetic pole pieces 15 and 17 to seal the inside of the anode body 1 with a vacuum ( 17,19) and the output side An insulating tube 21 made of ceramic joined to an upper portion of the quick pipes 17 and 19 to form an output portion, an exhaust pipe 23 joined to an upper portion of the insulating tube 21 to form an output portion, and the exhaust pipe 23. In the magnetron having one end is fixed to the vane (3) and the other end is fixed to the vane (3) to output the high frequency oscillated in the resonant cavity, the magnetron inside the output side metal pipe (17, 19) The first and second metal rings 25 and 25 'are joined to each other to form a resonant structure of 12.25 GHz, so as to attenuate the fifth harmonic component leaking to the outside of the magnetron. By attenuating the fifth harmonic component, not only the wireless communication failure can be prevented, but also the structure can be reduced in size and the manufacturing cost can be reduced.

Description

Magnetron Output Structure

1 is a partial longitudinal sectional view of a conventional magnetron,

2 is a schematic longitudinal sectional view of a magnetron according to an embodiment of the present invention;

Figure 3 is an enlarged cross-sectional view of the output structure of the magnetron according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

1: anode body 3: vane

5: filament 7,9: upper and lower end hat

11: Outer lead wire 13: Center lead wire

15: the first stimulation part 17: the second stimulation part

19: metal pipe 21: insulated pipe

23: exhaust pipe 23: metal ring

25,25 ': First and second metal ring 27: Antenna

The present invention relates to a magnetron used in a microwave heating device such as a microwave oven. In particular, a resonance structure of 12.25 GHz is formed between two pairs of first and second metal rings joined inside a metal tube that is an output of the magnetron. The structure of the output portion of the magnetron to prevent leakage of the fifth harmonic.

In general, there is a representative magnetron of the prior art is the Korean Patent Application No. 90-3669 filed by the applicant.

As shown in FIG. 1, the magnetron described in the publication protrudes toward the filament 5 inside the anode cylinder 1 so as to attenuate a plurality of kinds of harmonic components leaking to the outside of the magnetron to form a resonance cavity. A plurality of (even) vanes 3 are arranged, and the first and second magnetic pole pieces 15 and 17 for magnetic field convergence are arranged opposite to each other at the open end portions of the anode cylinder 1.

In addition, upper and lower portions of the first and second magnetic pole pieces 15 and 17 include metal tubes 17 and 19 for sealing the inside of the anode cylinder 1 with a vacuum. 17 is hermetically welded to the middle portion of the anode portion 1 or both side opening ends of the anode cylinder 1, and the first cylinder for the harmonic choke while acting an exhaust pipe inside the output side ends of the metal pipes 17 and 19. 50 and another harmonic choke second cylinder 51 are hermetically fixed to one end of the metal tube 19 via an insulating tube 21 made of ceramic.

In addition, the flange 19a of the metal tube 19 is hermetically sealed to the upper opening end of the anode cylinder 1 in a state of hermetically covering the first magnetic pole piece 15 to generate a fundamental wave of 2450 MHz. Let's do it.

In the metal tube 19, a second metal tube 52 and a third metal tube 53 are fixed, and a flange portion 52a extends outward on one side of the second metal tube 52. ceiling the antenna 27 is a through hole and a flange portion (19a) of the second harmonic wavelength (λ ₂₎ once the said metal tube (19) cylindrical portion having a length (L1) corresponding to the λ _2/4 of a penetrating It is integrally connected to.

In the third metal tube 53, a flange portion 53a extends outwardly in the lower portion thereof, and a through hole through which the antenna 27 penetrates is formed in the ceiling thereof, similarly to the second metal tube 52. , is connected to one end a flange portion (53a) of the cylindrical portion (53b) having a length (L2) corresponding to the _third λ / 4 of a wavelength (λ ₃₎ of the third harmonic.

Here, the space constituted by the cylindrical portion of the metal pipes 17 and 19, the cylindrical portion 52b and the flange portion 52a of the second metal pipes 17 and 19 acts as the first choke means 55. The space constituted by the cylindrical portion 52b of the second metal tube 52 and the cylindrical portion 53b of the third metal tube 53 acts as the second choke means 56, thereby providing The length of the first choke means 55 is set so as to attenuate harmonics lower than that of the second choke means 56.

Further, in order to shield the leakage of harmonics, a first cylinder 50 having a height L3 from the upper end of the insulated tube 21 is welded to the upper opening of the insulated tube 21.

That is, in the case of a general magnetron, the second harmonic (4900 MHz) to the seventh harmonic (7350 MHz) are regulated or recommended standards, but in the magnetron, the fifth harmonic (12.25 GHz) at the second harmonic (4900 MHz), which has a relatively high leakage power, is used. For the purpose of suppressing the band, a method of forming a choke structure of 1/4 wavelength of each harmonic is mainly used at the output of the magnetron.

By the way, in the magnetron of this type, it is not possible to sufficiently shield the harmonic components leaking to the outside of the microwave output including harmonic components corresponding to the fundamental waves of the 2450 MHz band and the integral multiple of the fundamental waves, and especially the leakage of the fifth harmonic. Because of this severe, there was a problem that not only cause radio communication problems, but also harmful to the human body.

In addition, the hot electrons emitted from the filament (5) to the vanes (3) form an electric field, wherein the hot electrons collide with the vanes (3) to reflect them, and thus the upper part serving as the vanes (3) and the electron escape preventing plate and Radio frequency interference noise is generated between the lower end hats 7 and 9 in the cavity resonance region 57 composed of the first and second magnetic pole pieces 15 and 17, the vanes 3, and the anode cylinder 1, respectively. In addition to the occurrence of wireless communication failure, in order to shield the leaked harmonics, since the second and third metal pipes 52 and 53 must be separately manufactured and arranged in the metal pipe 19, the configuration is complicated and the manufacturing cost increases. There was a problem.

Therefore, the present invention is made to solve the above problems, the present invention is made to solve the above problems, the object of the present invention is a pair of two bonded to the inside of the metal tube which is the output of the magnetron. A 12.25 GHz resonance structure is formed between the first and second metal rings to attenuate the fifth harmonic component leaking to the outside of the magnetron, thereby not only preventing wireless communication interference, but also having a simple structure and miniaturization. To provide a magnetron output structure that can reduce the manufacturing cost.

In order to achieve the above object, the output structure of the magnetron according to the present invention is a filament for emitting hot electrons, an anode body having a plurality of vanes arranged to form a resonant cavity near the center by surrounding the filament from the outside, and the anode A funnel-shaped first and second pole pieces fixed to an opening of the cylinder to form a magnetic path to uniformly flux the magnetic flux in the working space formed by the filaments and vanes, and fixed to the upper and lower portions of the first and second pole pieces. A metal tube sealing the inside of the anode cylinder with holes, a ceramic insulated tube joined to an upper portion of the output side metal tube to form an output portion, an exhaust pipe joined to an upper portion of the insulated tube to form an output portion, and once in the exhaust pipe. The part is fixed and the other end is fixed to the vane and outputs the high frequency oscillated in the resonance cavity. A magnetron equipped with a meander, wherein the first and second metal rings form a resonant structure of 12.25 GHz and are joined to an inside of the output side metal tube to attenuate a fifth harmonic component leaking to the outside of the magnetron. .

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

2 is a schematic longitudinal cross-sectional view of a magnetron according to an embodiment of the present invention, Figure 3 is an enlarged cross-sectional view of the output structure of the magnetron according to an embodiment of the present invention, the same name for the same parts as the conventional configuration And the same reference numerals are omitted, and redundant description is omitted.

As shown in FIG. 2, a plurality of (even) vanes 3 forming a plurality of resonant cavities so as to attenuate harmonic components leaking to the outside inside the anode cylinder 1 formed in a cylindrical shape by a copper plate or the like. It is arrange | positioned at equal intervals toward this axial direction, and these anode cylinders 1 and the vane 3 comprise an anode part.

In addition, near the tip side of the vane 3, inner and outer equalization rings 3a and 3b are arranged to walk the vane 3 one by one to change the capacitance at the upper and lower portions to obtain a constant resonance frequency. A working space is formed by the tip of the plurality of vanes 3 near the central axis of the anode cylinder 1, and in this working space, a filament wound in a spiral shape of thorium → tungsten or the like so as to radiate hot electrons (5 ) Is disposed coaxially with the anode cylinder 1.

Upper and lower end hats 7 and 9 which do not contribute to oscillation are fixed to both ends of the filament 5, and an outer lead line 11 made of molybdenum is welded to the bottom surface of the lower end hat 9. The central lead wire 13, which is a central support made of molybdenum, is welded to the lower end of the upper end hat through a through hole formed in the central part.

Here, the center lead wire 13 is bent at two positions in the middle portion while penetrating the lower end hat 9 and the filament 5 in a non-contact manner, and the outer and center lead wires 13 are metal pipes 41. And the first and second external connection terminals 45 and 47 which are connected to a power supply terminal (not shown) through a through hole formed in the insulating ceramic 43 to supply an operating current to the filament 5. It is.

In addition, the first and second magnetic pole pieces having a funnel shape to form a magnetic flux on both side openings of the anode cylinder 1 so as to form a magnetic flux uniformly in the working space formed by the filaments 5 and the vanes 3 ( 15 and 17 are seated at positions cut inside the both ends of the anode cylinder 1 to bend and fix the remaining outer edges of the both ends, and are hermetically weld-bonded, and the first and second pole pieces 15 and 17 are fixed. In the upper and lower portions of), metal tubes 17 and 19 for sealing the inside of the anode cylinder 1 with a vacuum are formed in the middle of the first and second magnetic pole pieces 15 and 17 or on both sides of the anode cylinder 1. It is hermetically welded to the opening end, respectively.

In addition, a ring-shaped permanent magnet 35 is disposed adjacent to the first and second magnetic pole pieces 15 and 17 at a predetermined distance from the outer surfaces of the metal tubes 17 and 19, respectively. Inside the output side ends of the output metal pipes 17 and 19, in which the first magnetic pole pieces 15 are fitted on one side of the cylinder 1, the first and second metal rings 25 and 25 'are provided on the output metal pipes 17 and 19. Is bonded to form a resonator structure of 12.25 GHz band.

In addition, an insulating tube 21 made of a ceramic made of ceramic is joined to an output end opening end of the output side metal pipes 17 and 19 so as to form an output part, and a metal ring 23a to an upper end of the insulating pipe 21. ), An exhaust pipe 23 made of copper is fixed.

In addition, near the inner central portion of the exhaust pipe 23, an antenna 27 derived from one of the vanes 3 passes through a through hole of the first magnetic pole piece 15 so as to output high frequency oscillated in the resonance cavity. While extending to the end of the antenna 27 is fixed by the exhaust pipe (23).

In addition, a plurality of aluminum heat sinks 31 extending in the radial direction of the tube are fitted and disposed on the outer circumferential surface of the anode cylinder 1 by clamp members 33c fixed to the yokes 33a and 33b. ) Is covered with the permanent magnet 35 by the yoke (33a, 33b) to form a porcelain.

In addition, a first gasket (37) is formed between the open ends of the upper yokes (33a, 33b) of the output side permanent magnet (35) by a metal net to prevent radio leakage at high frequencies. It is arrange | positioned through the.

Hereinafter, the structure and the effect of the output portion of the magnetron, which is the subject of the present invention, will be described with reference to FIGS. 2 to 3.

Two pairs of the first and second metal rings 25 and 25 'are hermetically joined to the inside of the output side side end of the output metal pipe 17 and 19 in which the first magnetic pole piece 15 is fitted on one side of the anode cylinder. As shown in 'D' of FIG. 3, the resonator structure of 12.25 GHz is shielded to shield the fifth harmonic component with high leakage in the harmonic components of the magnetron corresponding to the integral multiple of the fundamental wave of 2450 MHz band.

In the output side metal pipes 17 and 19, a first metal ring 23a is joined to the metal pipes 17 and 19 to form a fourth harmonic choke structure as shown in FIG. The fourth harmonic component is shielded from the outside by attenuating the fourth harmonic component among the harmonic components of the magnetron corresponding to an integer multiple of the fundamental wave in the 2450 MHz band.

In addition, an insulating tube 21 made of ceramic, which joins the first and second metal rings 25 and 25 'to the output side metal pipes 17 and 19 to form an output part, has an upper side on the output side of the metal pipes 17 and 19. It is joined to the open end, and the exhaust pipe 23 made of copper is fixed to the upper end of the insulated tube 21 via the metal ring 23a, and is formed between the metal ring 23a and the exhaust pipe 23. As shown in 'B' of FIG. 3, a third harmonic choke structure is formed.

Accordingly, in the third harmonic choke structure formed between the metal ring 23a and the pipe 23, the third harmonic component leaking to the outside is attenuated by attenuating the third harmonic component corresponding to the integral multiple of the 2450 MHz band fundamental wave. Let's do it.

On the other hand, near the inner central portion of the exhaust pipe 23, the antenna 27 doped from one of the vanes 3 passes through the through hole of the first magnetic pole piece 15 so as to output high frequency oscillated in the resonance cavity. While extending to the end of the antenna 27 is fixed by the exhaust pipe 23, the second harmonic choke structure as shown in 'A' of FIG. 3 between the antenna 27 and the exhaust pipe 23, Form.

Therefore, in the second harmonic choke structure formed between the antenna 27 and the exhaust pipe 23, the second harmonic component corresponding to the integral multiple of the fundamental wave of the 2450 MHz band is attenuated to shield the second harmonic component leaked to the outside.

In general, the choke constitutes 1/4 wavelength of the frequency to be suppressed, so that the admittance of the part is zero (impedance is infinite) to suppress the propagation of the frequency.

However, since the capacitance exists in the choke opening, the capacitance of the opening can be neglected when the frequency is low, so the length of the choke is close to 1/4 wavelength, but the higher the frequency, the greater the influence of the capacitance and the actual choke length. Is considerably shorter than 1/4 wavelength.

That is, the degree of attenuation of the specific frequency is significantly affected by the capacitance of the choke opening, the position of the choke structure, and the coupling degree with the antenna.

Of course, if the capacitance of the choke opening is increased or the distance between the choke metal ring and the antenna is close to block the radio waves of the frequency, the coupling between the waveguide of the microwave oven and the antenna and the choke metal ring are close to each other. As the phase light changes, the fundamental wave oscillation action causes a considerable disadvantage to the characteristics of the microwave oven.

Therefore, in the present invention, as shown in 'D' of FIG. 3 instead of the conventional choke concept, the fifth harmonic component leaking to the outside of the magnetron has a resonance structure of 12.25 GHｚ inside the metal tube that is the output of the magnetron. By joining the first and second metal rings 25 and 25 'to be formed, the fifth harmonic component with high leakage can be effectively shielded while maintaining the characteristics of the conventional magnetron.

When power is applied through the first and second external connection terminals 45 and 47 in the magnetron having the output unit structure as described above, the second external connection terminal 47 → the center lead wire 13 → the upper end hat. (7)-> Filament (5)-> Lower End Hat (9)-> External Lead Wire (11)-> First External Connection Terminal (45)-A Closed Circuit is Composed to Operate the Filament (5) by Heating Current .

At this time, when a predetermined voltage is supplied to the anode cylinder 1, hot electrons are emitted from the filament 5, and the released hot electrons act in the magnetic fields of the first and second magnetic pole pieces 15 and 17. High frequency oscillation is performed.

Therefore, the high frequency is transmitted to the cavity of the microwave oven through the output unit with a frequency of 2450MHz band oscillated by the anode cylinder (1).

As described above, according to the output structure of the magnetron according to the present invention, the magnetron is formed by forming a resonance structure of 12.25 GHz between two pairs of the first and second metal rings joined inside the metal tube that is the output of the magnetron. By attenuating the fifth harmonic component leaking to the outside, not only the wireless communication failure can be prevented, but also the structure can be reduced in size, and the manufacturing cost can be reduced.

Claims (1)

A filament 5 for emitting hot electrons, an anode cylinder 1 having a plurality of vanes 3 arranged to form a resonant cavity near the center by surrounding the filament 5 from the outside, and the anode cylinder 1 Funnel-shaped first and second magnetic pole pieces 15 and 17 fixed to an opening of the first and second magnetic pole pieces 15 and 17 to form a magnetic path uniformly in the working space formed by the filaments 5 and the vanes 3, Metal tubes 19 and 41 fixed to upper and lower portions of the first and second magnetic pole pieces 15 and 17 and sealing the inside of the anode cylinder 1 with a vacuum; One end portion is fixed to the insulated pipe 21 made of ceramic, the exhaust pipe 23 joined to the upper portion of the insulated pipe 21 to form an output portion, and the exhaust pipe 23 is attached to the vane 3. Magnet equipped with an antenna 27 having a fixed end and outputting a high frequency transmitted in the resonance cavity In the ron, the first and second metal rings 25 and 25 'have a resonant structure of 12.25 GHz in order to attenuate the fifth harmonic component leaking to the outside of the magnetron inside the output metal pipes 17 and 19. The output structure of the magnetron, characterized in that formed and bonded.