KR19990033681A - Anode assembly of magnetron - Google Patents

Abstract

The present invention provides an anode assembly of a magnetron that improves noise characteristics, especially in low bands. The present invention includes a cylindrical positive electrode body, a plurality of vanes disposed radially toward the center of the inner surface of the positive electrode body, coupled to the upper and lower portions of the positive electrode body, and having a central hole formed at a central portion thereof. And a second magnetic pole piece, wherein the anode assembly of the magnetron comprises a diameter of the center hole of the first and second magnetic pole pieces smaller than the diameter of the working space determined by the vane. According to the present invention, in the magnetic field convergence of the permanent magnet by the two magnetic pole pieces, the magnetic field is distributed in a straight line from the ends of the two magnetic pole pieces located in the working space, so that the magnetic field can be maintained uniformly, and thus low The noise characteristic in the frequency band can be improved.

Description

Anode assembly of magnetron

The present invention relates to a magnetron for a microwave oven, and more particularly, to an anode assembly of a magnetron having improved noise characteristics in a low band.

In general, as shown in FIG. 1, a magnetron for a microwave oven has a plurality of vanes 2 radially assembled on an inner wall of a cylindrical anode body 1, and is formed on the upper and lower portions of the vanes 2. The annular inner strap 3 and the outer strap 4 are electrically and mechanically fixed to the step grooves.

An antenna 5 is connected to one vane of the plurality of vanes 2 to draw energy of high frequency generated inside the anode body 1 to the outside, and has a funnel shape at the upper and lower openings of the anode body 1. The first and second magnetic pole pieces 6 and 7 for magnetic field convergence are arranged to face each other.

On both sides of the positive electrode body 1, the filament 8, which is a negative electrode, is fixed to the upper end shield 9 and the lower lower shield 10 by the upper end shield, and the upper end shield 9 and The lower shield 10 is supported and fixed by a metal center lead 11 and a side lead 12, and at the bottom of the center lead 11 and the side lead 12, a cathode ceramic 13 and an electrical input terminal are provided. The in terminal terminal 14 is provided.

The upper and lower portions of the anode body 1 are fixed to the upper shield cup 15 and the lower shield cup 16, and the upper shield cup 15 has an antenna ceramic 17 and an exhaust pipe 18. The other end of the antenna 5 is connected to the exhaust pipe 18.

A plurality of heat dissipation fins 19 are disposed on the outer circumferential portion of the cathode body 1, and the other end of the heat dissipation fins 19 is mechanically coupled to the lower yoke 20 having the exhaust hole, and the lower yoke 20 is provided. Near the top of the upper yoke 21 is coupled by a bolt.

A ring-shaped permanent magnet 22 is disposed on the outer circumferential portion of the upper shield cup 15 between the upper yoke 21 and the upper end of the positive electrode body 1, and the lower yoke 20 and the lower end of the positive electrode body 1 are disposed. A ring-shaped permanent magnet 23 is also disposed on the outer circumferential portion of the lower shield cup 16 therebetween.

In the drawings, reference numerals 24 and 25 denote choke coils and filter cases forming an input stage filter unit which serves to apply power to the cathode and prevent unwanted high frequency flowing in reverse.

In the magnetron of a general microwave oven configured as described above, when a predetermined electric energy is supplied to the terminal 14 electrically connected to the center lead 11 and the side lead 12, the filament 8 generates heat and heat electrons. Will emit.

The radiated hot electrons are the direct current high voltage applied between the filament 8 and the vane 2 and the permanent magnets 22 and 23 disposed on the outer surfaces of the upper shield cup 15 and the lower shield cup 16. By the influence of the constant magnetic flux distribution formed in the working space by the acceleration and rotation in the working space.

The hot electrons accelerated and rotated in this way, when the phase speed of the high frequency electric field between the vanes and the vanes are synchronized with the rotational speed of the electrons, the energy of the electrons is moved into the high frequency electric field and converted into micro energy. It is radiated into the cavity of the microwave oven to heat food.

At this time, a high frequency electric field is formed between the vanes 2 arranged radially on the anode body 1, and particularly, at the end of the vanes 2 closer to the filament 8, the gap between adjacent vanes is narrower, so that a high frequency is generated. An electric field is formed.

However, according to the conventional magnetron for microwave oven, as shown in FIG. 2, the first and second magnetic pole pieces 6 (for magnetic field convergence) respectively coupled to the upper and lower portions of the positive electrode body 1 ( The diameter D1 of the center hole of 7) is slightly larger than the diameter D2 of the working space C (typically, the center hole diameter D1 of the magnetic pole piece is 9.1 mm, and the diameter D2 of the working space is 9.0 mm). Accordingly, there is a problem that the magnetic field distribution in the working space is non-uniform, causing severe noise, particularly in a low frequency band in the range of 30 MHz to 1 GHz.

Therefore, the technical problem to be achieved by the present invention, that is, the object of the present invention is to solve the above problems of the conventional anode assembly of the magnetron, by making the magnetic field distribution in the working space uniformly formed in a straight line An anode assembly of a magnetron to improve noise characteristics in a low frequency band is provided.

1 is a longitudinal cross-sectional view of a typical microwave magnetron.

2 is a cross-sectional view showing main parts of an anode assembly of a conventional magnetron;

3 is a cross-sectional view showing main parts of the anode assembly of the magnetron according to the present invention;

Explanation of symbols on the main parts of the drawings

One; Anode body 2; Bain

6, 7; First and second magnetic pole pieces 9 and 10; Upper and lower end shield

C; Space

The object of the present invention is a cylindrical positive electrode body, a plurality of vanes disposed radially toward the center on the inner peripheral surface of the positive electrode body, the magnetic field is coupled to the upper and lower portions of the positive electrode body, the center hole is formed in the center In the anode assembly of the magnetron including the first and second magnetic pole pieces for the procedure, the diameter of the center hole of the first and second magnetic pole pieces is smaller than the diameter of the working space determined by the vane By providing an anode assembly of a magnetron according to the invention.

According to the present invention as described above, in the magnetic field convergence of the permanent magnet by the first and second magnetic pole pieces, the magnetic field between the ends (peripherals) of the first and second magnetic pole pieces located in the working space is distributed in a straight line. Therefore, the magnetic field can be kept uniform, and therefore the noise characteristics in the low frequency band can be improved.

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

3 shows an anode assembly of a magnetron according to the present invention, and according to FIG. A plurality of vanes (2) arranged radially toward the top, and the first and second magnetic pole pieces (6) (7) for funnel-shaped magnetic field convergence coupled to the upper and lower portions of the positive electrode body (1) and having a central hole formed in the center thereof. ) Is included.

An annular inner strap 3 and an outer strap 4 are electrically and mechanically fixed to stepped grooves formed on the upper and lower portions of the vanes 2, and one vane of the plurality of vanes 2 has an antenna. (5) is connected.

In addition, both ends of the filament 8, which is a cathode part, are fixed to both ends by upper and lower end shields 9 and 10 on the central axis of the working space C whose size is set by the vanes 2 described above. The upper and lower end shields 9 and 10 are supported by the center lead 11 and the side lead 12, and form a strong electric field in the working space C by the power applied thereto. .

As described above, the magnetic fields of the permanent magnets 22 and 23 are introduced into the working space in which the electric field is formed by the first and second magnetic pole pieces 6 and 7 provided at the upper and lower portions of the anode body 1. This causes the cycloidal motion of the electrons in the working space C, which is converted into microwave energy by the subsequent action and drawn out to the outside through the antenna 5.

At this time, a uniform magnetic field distribution in the working space C at the time of magnetic field convergence by the magnetic pole pieces 6 and 7 is required. To this end, in the present invention, the size of the center hole of the magnetic pole pieces 6 and 7 is made smaller than the size of the working space to induce a uniform magnetic field distribution, which is the magnetic pole pieces 6 and 7 in the magnetron. This is based on the theory that the magnetic field distribution in the working space becomes more uniform when the central hole size of the is smaller than the size of the working space (C).

That is, as shown in the drawing, the magnetic field is reduced by making the center hole diameter D1 of the magnetic pole pieces 6 and 7 smaller than before, so that the center hole edges of the magnetic pole pieces 6 and 7 are in the working space C. It is to be formed in a straight line. Here, the center hole diameter D1 of the pole piece should not be in contact with the upper and lower end shields 9 and 10 located in the working space, so that it is required to be made sufficiently small as possible. Preferably it is preferably formed to have a diameter of about 8.7mm to 8.9mm, most preferably 8.8mm in the illustrated example.

The operation of the anode assembly according to the present invention as described above is the same as in the prior art, but the present invention has a uniform magnetic field distribution in the working space C in the magnetic field convergence by the magnetic pole pieces 6 and 7. The occurrence of noise in the low frequency band due to the nonuniform distribution of the same magnetic field can be reduced.

As described above, the anode assembly of the magnetron according to the present invention has a magnetic field of the permanent magnet by the first and second magnetic pole pieces by sufficiently reducing the center hole size of the magnetic pole pieces within a range not in contact with the upper and lower end shields. In the procedure, since the magnetic field is distributed in a straight line from the ends (peripherals) of the first and second magnetic pole pieces located in the working space, the magnetic field can be kept uniform, thereby improving the noise characteristics in the low frequency band. have. This can greatly reduce product defects caused by noise, which is a great help for quality improvement.

In the above, one embodiment for carrying out the anode assembly of the magnetron according to the present invention has been illustrated and described, but the present invention is not limited to the above-described embodiment, and deviates from the gist of the present invention as claimed in the following claims. Without this, any person skilled in the art to which the present invention pertains may make various changes.

Claims (2)

A cylindrical positive electrode body, a plurality of vanes disposed radially toward the center on the inner circumferential surface of the positive electrode body, and the first and second magnetic pole pieces for magnetic field convergence coupled to the upper and lower parts of the positive electrode body and the center hole is formed in the center thereof In the anode assembly of a magnetron comprising a, The diameter of the center hole of the first and second pole pieces is smaller than the diameter of the working space determined by the vane anode assembly of the magnetron. The anode assembly of a magnetron according to claim 1, wherein the diameters of the center holes of the first and second pole pieces are in the range of 8.7 mm to 8.9 mm.