JP2002190400A - Microwave apparatus and controlling method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microwave apparatus, which bearing a magnetron, is a moving type, assuring for longer service life of the magnetron and higher reliability. SOLUTION: The microwave apparatus of moving type which comprises the magnetron is provided, and a means is provided by which a filament of the magnetron is always electrified and heated at all times, when the microwave device is moved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a microwave device using a magnetron as an oscillation tube, and more particularly to a microwave device having a moving mechanism and a control method thereof.

[0002]

2. Description of the Related Art In general, as a microwave device using a magnetron as an oscillating tube, there are known industrial devices such as a cooking device, a sterilizing device, a drying device, and a plasma device of a semiconductor manufacturing apparatus.

[0003] When used for cooking, sterilization, drying, etc., the object is heated using microwaves (high frequency) generated by a magnetron, so that the heating efficiency is high, so that it is not only for home use, but also for leisure use and further for business use. It is also heavily used.

In the case of leisure or business use, there is a case where a magnetron and a drive power supply are mounted on a moving object such as a camper or a bullet train or an aircraft, and these vehicles or aircraft are used as microwave devices. Ari, in such a microwave device, it is required to ensure the reliability of the magnetron against vibrations and shocks generated accompanying the movement.

FIG. 7 is a sectional view showing an example of a magnetron cathode structure used in a microwave device. In FIG. 7, reference numeral 86 denotes an insulator, and the insulator 86 is formed of alumina ceramic or the like. Cathode supports 87 and 88 made of a refractory metal such as molybdenum are inserted through two through holes 861 provided in the insulator 86, and the cathode supports 87 and 88 are insulated via a metal fitting 89. It is brazed and fixed to the body 86 in an airtight manner.

[0006] One end of a substantially cylindrical sealing metal body 90 having a flange portion brazed to the anode cylinder is brazed and fixed to the insulator 86. Further, upper and lower end shields 91 and 92 made of molybdenum or the like are fixed to the respective tips of the cathode supports 87 and 88, and both ends of the filament 93 are fixed to the upper and lower end shields 91 and 92 by brazing. I have. This filament 9
Reference numeral 3 denotes a cathode support 88 extending through a through hole provided in the lower end shield 92, and penetrates a position substantially corresponding to the central axis.

FIG. 8 is a sectional view of a core wire 931 constituting the filament 93 shown in FIG. The filament 93 is generally formed by spirally shaping a high melting point metal wire mainly containing tungsten (W), and the surface layer 932 of the core wire 931 is formed with a carbonized layer in order to obtain good electron emission characteristics.

[0008] As a technique related to the magnetron having the structure as shown in FIGS.
Japanese Unexamined Patent Publication No. 96030 and Japanese Unexamined Patent Publication No. Hei 7-220865 and Japanese Unexamined Patent Publication No. 2000-291957 as techniques related to the control of microwave ovens, and Japanese Unexamined Patent Publication No. 2000-291957 as Japanese Unexamined Patent Publication No. JP-A-2000-52845 is known.

[0009]

In the above-described microwave device of the prior art, in particular, a microwave device mounted with a magnetron and moving, as described above, the reliability of the magnetron with respect to the vibration and shock generated accompanying the movement is described. Is an issue.

A magnetron is a kind of electron tube, but since most of the vacuum envelope is made of a metal material such as molybdenum and ceramic, it is compared with other cathode ray tubes having a glass envelope. High mechanical strength against external impact.

However, the material and shape of the filament in the magnetron are substantially the same as those in other electron tubes.
Countermeasures against vibration and shock have a problem common to electron tubes.

On the other hand, in the magnetron filament, the surface layer of the core wire has a carbonized layer in order to obtain good electron emission characteristics as described above with reference to FIG. Since this carbonization treatment is a high-temperature treatment in a vacuum, for example, a high-temperature treatment of two hundred and several hundred degrees Kelvin, the core wire itself is recrystallized, the filament becomes brittle, and measures against vibration and impact become an issue.

As a countermeasure, for example, there is a means for preventing the brittleness by lowering the carbonization temperature, but in this method, the electron emission characteristics are lowered, and this is not a preferable countermeasure. In addition, a method of fixing the magnetron itself and a measure for improving the breaking strength of the filament have been studied, but further measures have been a problem.

On the other hand, from another point of view, as part of the above measures, the impact strength in transporting and handling the magnetron is specified by JIS, and is currently specified to be 100 G or less. Therefore, use beyond this is limited in terms of reliability.

Because of these restrictions, the field of application of the microwave device using the magnetron is limited. In order to expand the field of use, it is necessary to extend the life of the magnetron and ensure high reliability. Has become.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a microwave device having a long-life and highly reliable magnetron.

[0017]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for continuously heating a magnetron filament by means of, for example, energizing heating while moving a microwave device equipped with the magnetron. This makes it possible to provide a microwave device equipped with a long-life and highly reliable magnetron by preventing the fragility of the microwave.

A typical configuration of the present invention is described as follows. That is, (1) a magnetron, a drive power supply unit for the magnetron, a moving mechanism for mounting and moving the magnetron and the drive power supply unit, and a heating mechanism unit for heating a filament of the magnetron when the magnetron is moved. It is characterized by. (2) In the above (1), the heating of the filament is energization heating for energizing the filament. (3) In the above (1) or (2), the moving mechanism is a car, a train, an aircraft, or another moving body. (4) In the above (1), the driving power supply unit of the magnetron is further provided with a protection circuit for a high-voltage transformer inserted into the anode circuit of the magnetron. (5) A microwave apparatus comprising: a magnetron; a driving power supply unit for the magnetron; a moving mechanism for mounting and moving the magnetron and the driving power supply unit; and a heating mechanism for heating a filament of the magnetron when the magnetron moves. As a control method, the filament is always energized and heated while the magnetron is moving.

With the above-described configuration, of the problems to be solved by the magnetron, it is possible to prevent the occurrence of disconnection due to the movement caused by the weakening of the filament, and to mount a long-life and highly reliable magnetron. It is possible to provide a microwave device that has been used.

It should be noted that the present invention is not limited to the above configuration and the configuration of the embodiment described later, and various changes can be made without departing from the technical idea of the present invention.

[0021]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram for explaining the configuration of the microwave device of the present invention. In FIG. 1, reference numeral 1 denotes a magnetron. The magnetron 1 is driven by a drive power supply unit 2 and oscillates a predetermined microwave. Reference numeral 3 denotes a moving mechanism on which the magnetron 1 and the drive power supply unit 2 are mounted.

Reference numeral 4 denotes a heating mechanism, which is mounted on the moving mechanism 3 together with the magnetron 1 and the driving power supply 2 and heats the filament of the magnetron 1 when the moving mechanism 3 is started. This heating can be performed according to a predetermined schedule before the start of the start, but the heating is always performed at least during the movement. The heating mechanism 4 can also be integrated into the drive power supply 2. 5
Is a housing that houses the magnetron 1 and is mounted on the moving mechanism 3. Reference numeral 6 denotes a microwave device.

In the microwave device 6, at least during the movement from the start of the movement, the filament of the magnetron is always in a heated state, and the disconnection failure can be remarkably reduced as compared with the conventional non-heating system.

That is, the present inventors conducted a comparative experiment on the breaking strength of the filament with respect to the vibration and impact applied to the magnetron, when the filament was heated and when it was not heated as in the prior art.

In the experiment, a magnetron was fixed to a sample mounting table, and the load value at which the filament was disconnected under the conditions shown in Table 1 was measured under the conditions shown in Table 1 using a test machine capable of changing the impact load by changing the falling angle of the hammer.

[0027]

[Table 1] As is apparent from Table 1, the conventional filament non-heated samples C and D were broken at 415 G as with the load of 395 G, respectively, whereas the samples A and B in which the filaments were electrically heated at the rated value were loaded. Even if it exceeds 580 G, there is no breakage yet, and it can be confirmed that the impact resistance is remarkably excellent, and the improvement of the breakage strength of the filament has become clear as compared with the conventional case.

Next, FIGS. 2A and 2B show a specific example of a camper car according to an embodiment of the microwave apparatus of the present invention. FIG. 2A is a side view, and FIG. FIG.

2 (a) and 2 (b), reference numeral 7 denotes a vehicle body which is a moving mechanism, in which a plurality of seats 7a are arranged, and a part of these seats 7a is forward and backward. It is possible to slide. Reference numeral 8 denotes a cabin. The cabin 8 is mounted in the vehicle main body 7 while the vehicle main body 7 is moving, and is pulled out and used when necessary while the vehicle is stopped. The cabin 8 has a shower room in the rear part 8a and a front part 8b
Is a kitchen space in which a microwave oven 9 using a magnetron as an oscillation tube is installed.

The microwave oven 9 has a drive power supply and a heating mechanism. The heating mechanism is interlocked with a start switch for running the vehicle main body 7, and is configured to always energize the magnetron filament while the vehicle main body 7 starts running. 8c is a caster of the cabin 8, and 10 is a microwave device.

In the microwave device 10 having such a configuration,
From the start of traveling, during traveling, at the time of direction change including stopping and retreating, and depending on the road surface conditions, large and small vibrations and impacts are applied to the magnetron, causing wire breakage of the filament,
Since the filament is constantly heated during the movement, disconnection failure can be remarkably reduced as compared with the conventional non-heating method.

Here, in this embodiment, the heating of the filament is performed by electric heating. However, this heating method is preferable in consideration of the structure of the magnetron which is a vacuum tube.

In the above embodiment, the camping car has been described as a vehicle. However, it is needless to say that the present invention can be applied to all other moving microwave devices such as other vehicles, aircraft other than vehicles, and ships.

Next, a specific configuration example of the magnetron used in this embodiment will be described. FIG. 3 is a diagram showing a cross-sectional structure of an example of the magnetron used in the microwave device of the present invention.

In FIG. 3, reference numeral 11 denotes a filament serving as a thermoelectron emission source, 12 denotes a plurality of anode vanes, 13 denotes an anode cylinder (anode cylinder), 14 and 14a denote annular permanent magnets, and 15 and 15a denote shallow dishes. Magnetic poles, 16 and 16a are yokes, 17 is an antenna lead, 18 is an antenna, 19 is an exhaust pipe, 20 is an antenna cover, 21 is an insulator, 22 is an exhaust pipe support, 23 is a working space, and 24 and 25 are inside. And outer straps, 26 and 27 are cap-shaped upper and lower sealing metals,
28 is a metal gasket, 29 is an output section, and this output section 2
9 is the antenna lead 17, the antenna 18, the exhaust pipe 1
9 and an antenna cover 20.

Numeral 30 denotes a magnetic circuit part, which is provided with the permanent magnets 14, 14a, which are magnetic sources, and shallow dish-shaped magnetic poles 15, 15a,
Further, yokes 16 and 16a are included. 31 is an upper end shield, 32 is a lower end shield, 33 and 34 are cathode leads (33 is a center lead, 34 is a side lead), 35 is an input side ceramic, 36 is a cathode terminal, 37
Is a lead-out lead, and 38 is a cathode portion. The cathode portion 38 is a cathode filament 11, which serves as a thermionic emission source, upper and lower end shields 31, 32, and a cathode lead 3.
3, 34, etc.

An anode section 39 includes a plurality of anode vanes 12, an anode cylinder 13, inner and outer straps 24 and 25, and the like. 41 is a choke coil, 42 is a feedthrough capacitor, 43 is a filter case,
Reference numeral 4 denotes a lid, and 45 denotes a cooling fin.

In FIG. 3, the spiral filament 11
A plurality of anode vanes 12 are fixed to the anode cylinder 13 by brazing or the like, or are integrally formed with the anode cylinder 13 by extrusion molding.

Above and below the anode cylinder, magnetic poles 15 and 15a made of a ferromagnetic material such as soft iron and a cylindrical permanent magnet 14,
14a is arranged.

The magnetic flux generated from the permanent magnets 14 and 14a passes through the magnetic poles 15 and 15a, enters the working space 23 formed between the filament 11 and the anode vane 12, and gives a necessary DC magnetic field in the axial direction.

The yokes 16, 16a are provided with permanent magnets 14, 14,
a, which constitutes a magnetic circuit through which the magnetic flux of a passes. The magnetic circuit includes yokes 16, 16a, permanent magnets 14, 14a,
And the magnetic poles 15 and 15a.

The filament 11 having a negative high voltage
The electrons emitted from the electrodes form a high-frequency electric field in each anode vane 12 while performing a circular motion under the action of the electric and magnetic fields.

The formed high-frequency electric field is applied to the antenna lead 1
The signal reaches the antenna 18 through the antenna 7 and is output from the antenna cover 20 to an external device.

The filament 11 is generally made of thorium oxide (ThO 2) in consideration of electron emission characteristics and workability.
Is used and supported by an upper end shield 31, a lower end shield 32, and cathode leads 33 and 34.

The cathode leads 33 and 34 are generally made of molybdenum (Mo) from the viewpoint of heat resistance and workability.
A terminal board 36 brazed to the upper surface of the input ceramic 35 with a silver solder or the like is connected to external lead-out leads 37 connected to the choke coil 41.

A filter structure comprising a filter case 43 for supporting a choke coil 41 and a feedthrough capacitor 42 and a lid 44 for closing the filter case is mounted below the magnetron.

The choke coil 41 connected to the external leads 37, 37 constitutes an LC filter with the feedthrough capacitor 42, and suppresses low frequency components transmitted from the cathode lead. Note that the high frequency component is
And its lid 44 is shielded.

The cooling fins 45 installed on the outer periphery of the anode cylinder 13 dissipate heat accompanying the operation of the magnetron.

Next, FIGS. 4 and 5 are views showing the cross-sectional structure of another example of the magnetron used in the microwave device of the present invention. FIG. 4 is a plan view of a main part of the anode, and FIG. A-
FIG. 3 is a sectional view taken along line A.

In FIG. 4 and FIG.
5, eight anode vanes 52, one example of which is shown in FIG. 5, are arranged so as to protrude from the anode cylinder 53 toward the filament 51 with a length L1 and a height H1.
Reference numeral 2 denotes inner and outer straps 64, 6 having two different diameters.
5 are connected to every other in strap storage grooves 521 and 522 at both upper and lower edges of the anode vane 52 on the filament 51 side.

The anode vane 52 is an anode cylinder 53
Has notches 523, 524 at the upper and lower edges of the side.
The cut depth H2 is related to the inductance of the anode vane. D1 is the inside diameter of the anode cylinder 53, and D2 is the outside diameter.

The above structure is called a multi-segment anode structure, which is a cavity resonator divided by a plurality of anode vanes. The resonance frequency is determined by the capacitance and inductance of each resonator, that is, the magnetron. Oscillation frequency is determined.

Specifically, the inductance is determined by the specifications of the anode vane and the anode cylinder, while the capacitance is determined by the capacitance determined by the size of the space formed by the adjacent anode vanes and the upper and lower ends of the anode vane. There are both capacitances formed between the inner and outer straps disposed on the surface, and the oscillation frequency is determined by these capacitances and the inductance. In the examples shown in FIGS. 24
An anode structure 50 mH _Z.

Furthermore, the upper and lower ends of the spiral filament 51 disposed at the center of the anode cylinder 53 are fixed to an output end shield (upper end shield) 71 and an input end shield (lower end shield) 72, respectively. Have been. Then, the output side and input side end shields 7
Reference numerals 1 and 72 are supported by rod-shaped cathode leads 73 and 74.

FIG. 6 is a circuit diagram showing an example of a drive circuit constituting a drive power supply section and a heating mechanism section of the magnetron used in the microwave device of the present invention. The input terminal 75, the first switch 76, Transformer 77, magnetron 78, timer 79, electromagnet relay 80, second switch 81, high voltage transformer 82, capacitor 83, diode
C.

The driving circuit having the above configuration operates as follows. First, a predetermined voltage is applied to the input terminal 75. At this time, the first switch 76 is connected to the primary preheating terminal 771 of the heater transformer 77. Timer-7
9 is set to OFF, so that the electromagnetic relay 80
Does not operate, and therefore the second switch 81 is also open. By this voltage application, the filament 781 of the magnetron 78 is electrically heated.

In this state, the filament 781 is moved by moving the microwave device as shown in FIGS.
Disconnection can be prevented.

On the other hand, when the timer 79 is set to ON, the electromagnet relay 80 operates, the second switch 81 closes, the high voltage transformer 82 operates, and the secondary Side capacitor 83 and diode 8
A high voltage is applied to the anode 782 of the magnetron 78 via the half-wave voltage rectifying circuit constituted by 4 to start oscillation.

The operation of the electromagnet relay 80 closes the second switch 81, and at the same time, the first switch 76 also operates the primary operation terminal 772 of the heater transformer 77.
Switch to the side, the filament 78 of the magnetron 78
1 is energized and heated at the operating voltage, and the operating voltage on the operating terminal 772 side is constantly applied during the oscillation of the magnetron 78.

In the circuit shown in FIG. 6, when the magnetron 78 is oscillated by the timer 79, the input terminal 75
The timer is set to operate about 5 seconds after the application of a predetermined voltage. However, if the setting of the timer -79 is turned off, the heater transformer 77 is always connected to the preheating terminal 771 side. Therefore, although the filament 781 is in the state of energization and heating, the high voltage transformer 82 is in the OFF state and does not oscillate the microwave.

Therefore, in the circuit shown in FIG. 6, the breaking of the filament 781 due to the movement of the microwave device is prevented.
It can be easily realized by turning off the timer -79.

Here, in the circuit configuration of FIG. 6, both the first switch 76 and the second switch 81 are connected to the electromagnet relay 80.
, But the first switch 76 is always operated
2 is turned on and off with respect to the electromagnet relay 8.
A value of 0 controls the second switch 81 to turn ON / OFF the anode voltage application, and the same effect can be obtained.

When the microwave device in which the magnetron is oscillating is moved, there is a possibility that the filament of the magnetron and the anode may come into contact with each other due to vibration or impact. When the filament comes in contact with the anode, a short-circuit current flows on the secondary side of the high-voltage transformer connected to the anode, and the high-voltage transformer may be burned.

As one of the measures, a protection circuit having a function of attaching a thermoswitch to the high-voltage transformer to sense the temperature of the high-voltage transformer and turning off the anode voltage while the filament heating is continued in the event of an abnormality is added. A highly reliable microwave device can be realized.

The present invention is not limited to the above-described embodiment, and various changes can be made without departing from the technical idea of the present invention.

[0066]

As described above, according to the present invention,
By heating the magnetron filament mounted on the microwave device during the movement of the microwave device, disconnection of the filament can be prevented. And a microwave device equipped with a magnetron can be used in a wider range of industries.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a microwave device according to the present invention.

FIG. 2 (a) shows a specific example of a camper of one embodiment of the microwave apparatus of the present invention, and FIG.
(B) is a schematic plan view.

FIG. 3 is a sectional view of an example of a magnetron used in the microwave device of the present invention.

FIG. 4 is a plan view of a main part of an anode part of another example of the magnetron used in the microwave device of the present invention.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a circuit diagram illustrating an example of a driving circuit of the microwave device according to the present invention.

FIG. 7 is a sectional view showing an example of a magnetron cathode structure used in a conventional microwave device.

8 is a sectional view of a core wire constituting the filament shown in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 78 Magnetron 2 Drive power supply part 3 Moving mechanism 4 Heating mechanism part 6, 10 Microwave device 7 Vehicle body 8 Cabin 9 Microwave oven 11 Filament 12 Anode vein 76 First switch 77 Heater transformer 79 Timer-80 Electromagnetic relay 81 Second switch 82 High voltage transformer 83 Capacitor 84 Diode 781 Filament 782 Anode.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshio Furutaki 3350 Hayano, Mobara-shi, Chiba F-term (reference) in Hitachi Electronics Devices, Ltd. 3K086 AA06 AA10 BA08 CD30 DB30 FA06 FA07 3L086 AA01 BA10 CC30 DA16 DA18 DA30 3L113 AB07 AC12 AC43 AC63 DA18 DA24 DA30

Claims (7)

[Claims] 1. A magnetron, a driving power supply for the magnetron, a moving mechanism for mounting and moving the magnetron and the driving power supply, and a heating mechanism for heating a filament of the magnetron when the magnetron moves. A microwave device characterized by the above-mentioned. 2. The microwave apparatus according to claim 1, wherein the heating of the filament is energization heating for energizing the filament. 3. The microwave apparatus according to claim 1, wherein the moving mechanism is an automobile. 4. The microwave apparatus according to claim 1, wherein the moving mechanism is a train. 5. The microwave apparatus according to claim 1, wherein said moving mechanism is an aircraft. 6. The microwave device according to claim 1, wherein the driving power supply unit of the magnetron further includes a protection circuit for a high-voltage transformer inserted into an anode circuit of the magnetron. 7. A micro-motor comprising: a magnetron; a driving power supply for the magnetron; a moving mechanism for mounting and moving the magnetron and the driving power supply; and a heating mechanism for heating a filament of the magnetron when the magnetron is moved. A method for controlling a microwave device, wherein the magnetron constantly heats a filament while moving.