JPS6323868Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a magnetron, particularly to a magnetron stem structure.

In general, magnetrons are widely used for heating or defrosting foods by being attached to microwave ovens or defrosting machines because they efficiently generate high-frequency output.

FIG. 1 is a sectional view of essential parts of an example of a conventional magnetron. In the figure, 1 is an anode cylinder formed into a cylindrical shape from, for example, oxygen-free copper,
Vanes 2 forming a plurality of radially divided resonant cavities are provided on the inner wall surface of the anode cylinder 1, and the anode 3 is formed by the anode cylinder 1 and the vanes 2.
is configured. A working space 4 formed by a plurality of vanes 2 is formed on the central axis of this anode 3, and inside this working space 4, a thermionic electron beam formed with a thorium-containing tungsten wire or the like in a spiral shape is formed. A radiation cathode 5 is arranged. In this case, the working space 4 is between the thermionic emission cathode 5 and the tip of the vane 2, and a space having a predetermined distance is formed. Further, 6 and 7 are end shields fixedly arranged at both ends of the thermionic emission cathode 5, respectively, to prevent electrons from deviating in the direction of the central axis. Furthermore, this end shield 7 has a side support 8a and a center support 8a.
b are fixed, respectively, to fixedly support the thermionic emission cathode 5 and supply current for its operation. The other end sides of these side supports 8a and center support 8b extend outward via a ceramic spacer 9. In this case, the ceramic spacer 9 connects the side port 8a and center support 8b to each other to prevent thermionic emission cathode 5 from breaking due to external impact. Cone-shaped magnetic poles 10 and 11 are fixedly arranged on both ends of the anode 3, respectively, and form a magnetic path that converges a uniform magnetic flux within the working space 4. Furthermore, the cone-shaped magnetic pole 1
Vacuum sealing members 12 and 13 made of iron material, for example, for vacuum-sealing the inside of the anode 33 are fixed to the ends of the anode 3 by arc welding or the like, respectively, on the outer surfaces of the anodes 0 and 11. Vacuum sealing member 1
Cylindrical permanent magnets 14 and 15 are placed on the outer surfaces of 2 and 13.
are placed close to each other. Further, an output side insulator 16 formed in a cylindrical shape of ceramic or the like is fixedly arranged on the outer surface side of the upper vacuum sealing member 12, and the tip of this output side insulator 16 is provided with an exhaust gas made of a copper pipe. A pipe 17 is fixed, and an antenna conducting wire 18 connected to one end of the vane 2 is hermetically welded to this exhaust pipe 17. Further, the outer surface of the exhaust pipe 17 is covered with a metal cover 19, which protects the press-contact portion of the exhaust pipe 17, prevents sparks due to electric field concentration, and functions as a high frequency antenna. A heat sink 20 made of an aluminum plate is fitted onto the outer peripheral surface of the anode 3, and is covered together with the outer peripheral surfaces of the permanent magnets 14 and 15 by a yoke 21 for forming a magnetic path. Further, an input side insulator 22 formed of ceramic or the like is fixedly arranged on the outer surface side of the lower vacuum sealing member 13, and this input side insulator 22 is provided with the side supports.
The center support 8a and the center support 8b are arranged through the
This side support 8a, center support 8b
A choke coil 23 for preventing leakage of unnecessary radio waves is connected to the tip. The end of the lower vacuum sealing member 13 is provided with the side support 8.
a, center support 8b, shield case housing the input side insulator 22 and choke coil 23;
The hole 24a of the base 24 is fitted to block unnecessary radio waves leaking from the input section.

In the magnetron configured in this way,
When a predetermined input is supplied from an external terminal (not shown) through the choke coil 23, the thermionic emission cathode 5
When the anode 3 is heated and a predetermined voltage is supplied to the anode 3, thermoelectrons are emitted from the thermionic emission cathode 5. Then, these thermoelectrons act within the magnetic field of the working space 4 to generate high frequency oscillation, and this output is transmitted through the antenna conductor 18 to the exhaust pipe 17 and the metal cover 1.
9, the radiation is emitted into the oven of a microwave oven, for example.

However, in the magnetron having the above configuration, the lower vacuum sealing member 13 is composed of a cylindrical portion 13a, a flat portion 13b, and a maximum outer diameter portion 13c, as shown in FIG. 13c has a magnetic pole 11 sandwiched between the flat plate part 13b and the anode 3 and is fixed to the end of the anode 3, and the flat plate part 13b has a permanent magnet 15 attached to the outer surface of the yoke 2.
1, and the cylindrical portion 13a is held by the seal.
It is configured to be forcibly press-fitted into the hole 24a of the case 24. For this reason, the side support 8
a, the entire stem structure consisting of the center support 8b, the vacuum sealing member 13, and the insulator is pushed toward the anode 3 side. At this time, an uneven force is applied to the vacuum sealing member 13, and a part of the flat part 13b, especially the part A that does not contact the magnetic pole 11, is deformed, and the central axis of the cathode 5 is largely eccentric with respect to the anode 3. There is. In addition, the anode 3 was exposed to high temperature during vacuum evacuation.
Since the pressure inside is reduced, the flat part 13b is deformed,
The relative positions of the cathode 5 and anode 3 may move or may deform unevenly and become eccentric. Furthermore, when attaching the choke coil 23 to the side support 8a and center support 8b for preventing the propagation of unnecessary radio waves from the cathode 5 to the outside, the side support 8a and the center support 8b are
An external force was applied to the vacuum sealing member 13 through the vacuum sealing member 13, causing eccentricity as described above.

Therefore, the object of the present invention was to provide a magnetron having a stem structure that prevents eccentricity of the cathode and fluctuations in relative position with respect to the central axis of the anode. It's about doing.

In order to achieve this purpose, the magnetron according to the present invention has a vacuum sealing member provided with a plurality of axial tabs. The magnetron according to the present invention will be described in detail below with reference to the drawings.

2A, 2B, 2C and 2D are a sectional view of a main part, a sectional view -', a bottom view of a main part, and a side view of a main part showing an example of a magnetron according to the present invention, particularly a lower vacuum sealing member. In these figures, the lower vacuum sealing member 25 consists of a cylindrical part and a flange part integral with the cylindrical part, and a flat part 25 of the flange part extends from the cylindrical part 25a.
Four tabs 25c projecting in the radial direction of the tube along the axial direction are formed by press molding over a portion of b.

According to such a configuration, the vacuum sealing member 25
The tube axis direction is reinforced by providing four tabs 25c along the tube axis direction, so even if force is applied in the tube axis direction, eccentricity and relative imbalance between the cathode 5 and anode 3 are prevented. No positional fluctuation occurs at all, and good characteristics can be obtained. Further, since the tab 25c is provided so as to protrude inside the vacuum sealing member 25, there is no possibility of interfering with the fitting with the hole 24a of the shield case 24, and the permanent magnet 15
There is no fear that the tab 25c will come into contact with the inside of the holder. Furthermore, since the turbo 25c is provided at a location close to the cylindrical portion 25a side of the flat portion 25b, there is no risk that the turbo 25c will ride on the magnetic pole 11 as shown in FIG. Member 25
It can be used for positioning. Note that the turbo 25c may be provided as long as possible in the radial direction of the flat portion 25b, and in that case, it is preferable that the magnetic pole 11 is also provided with a recessed portion at a position facing the turbo. In this case, the vacuum sealing member is even more strongly reinforced and becomes less likely to deform.

As explained above, the magnetron according to the present invention has a plurality of tabs provided in the lower vacuum sealing member along the tube axis direction, thereby effectively reinforcing the magnetron.
The extremely excellent effect of suppressing the eccentricity of the central axis and fluctuations in the relative position between the cathode and the anode, and greatly improving quality and reliability, can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part showing an example of a conventional magnetron, and FIGS. 2 a, b, c, and d are cross-sectional views of main parts showing an example of a magnetron according to the present invention, particularly a vacuum sealing member, and -' cross-sectional views. They are a bottom view of the main part and a side view of the main part. 1... Anode cylinder, 2... Vane, 3... Anode,
4... Working space, 5... Cathode, 6... Upper end shield, 7... Lower end shield, 8a...
Side support, 8b... Center support, 9
... Ceramic spacer, 10 ... Upper magnetic pole, 1
1... Lower magnetic pole, 12... Upper vacuum sealing member, 1
3... Lower vacuum sealing member, 13a... Cylindrical part, 1
3b...Flat part, 13c...Maximum outer diameter part, 14,
15... Permanent magnet, 16... Insulator, 17... Exhaust pipe, 18... Antenna conductor, 19... Metal cover, 20... Heat sink, 21... Yoke, 22...
Insulator, 23...Choke coil, 24... Sea
lower case, 25...lower vacuum sealing member, 25a
... Cylindrical part, 25b... Flat part, 25c... Tubular part.

Claims (1)

[Scope of utility model registration request] A cylindrical anode having a plurality of vanes arranged radially around the cathode is disposed at both ends of the magnetic pole and is vacuum-sealed to guide the magnetic flux of the permanent magnet to the center of the anode. In a magnetron having at least vacuum sealing members on the input and output sides, the vacuum sealing member on the input side consists of a cylindrical part and a flange part integral with the cylindrical part, and the flange part is along the tube axis direction of the cylindrical part and A magnetron characterized by a plurality of tabs protruding from the inside of a vacuum over a flat part of the magnetron.