JP2001283744A - Magnetron apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetron apparatus capable of improving oscillation efficiency. SOLUTION: The magnetron apparatus is provided with a vacuum tube part 1 having a negative electrode filament 20 in a cylindrical positive electrode 11, and magnets 22a, 22b arranged on both ends of the cylindrical positive electrode 11 of the vacuum tube part 1. And a magnetic circuit part 2, which is composed of yokes 25a, 25b surrounding the cylindrical positive electrode 11 and the magnets 22a, 22b, is provided. In a position of an axial direction of the tube of the cylindrical positive electrode 11, a maximum position of temperature distribution of the negative electrode filament 20, and a minimum position of magnetic flux density distribution of the magnetic circuit part 2 are substantially made the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron device used for microwave heaters such as microwave ovens, industrial heaters and the like.

[0002]

2. Description of the Related Art A conventional magnetron device includes a vacuum tube portion, a magnet disposed on both ends of a cylindrical anode of the vacuum tube portion, and a magnetic circuit portion including a cylindrical anode and a yoke surrounding the magnet. Things.

[0003]

SUMMARY OF THE INVENTION In recent years, from the viewpoint of energy saving worldwide, improvement of the oscillation efficiency of the magnetron device has been demanded. However, in the above magnetron device, the oscillation efficiency of about 73% is limited, and it is difficult to further improve the oscillation efficiency. Note that the oscillation efficiency is a ratio of a DC input (anode voltage × anode current) applied between the anode and the cathode of the vacuum tube unit to microwave power radiated from the antenna of the vacuum tube unit.

The present invention has been made in view of the above, and provides a magnetron device capable of improving the oscillation efficiency.

[0005]

A magnetron device according to the present invention comprises: a vacuum tube section having a cathode filament in a cylindrical anode; and magnets disposed on both ends of the cylindrical anode of the vacuum tube section; In a magnetron device including a magnetic circuit portion including a cylindrical anode and a yoke surrounding the magnet, a position at which a temperature distribution of the cathode filament is highest in a position in a tube axis direction in the cylindrical anode and the magnetic field. The position where the magnetic flux density distribution of the circuit portion is the lowest is substantially the same.

With this configuration, the loss of electron motion in the cylindrical anode is reduced, and the oscillation efficiency can be improved.

Further, the magnets arranged at both ends of the cylindrical anode have different magnetic forces.

According to this configuration, the oscillation efficiency can be improved by a simple means of merely changing the magnetic force of the magnet in the magnetic circuit after the vacuum tube is manufactured.

[0009]

Embodiments of the present invention will be described below.

As shown in FIG. 1, a magnetron device according to an embodiment of the present invention includes a vacuum tube 1 and a magnetic circuit 2.
And a radio wave leakage prevention unit 3. The position where the temperature distribution of the cathode filament 20 is the highest in the tube axis direction of the vacuum tube unit 1 and the position where the magnetic flux density distribution of the magnetic circuit unit 2 is the lowest are substantially defined. It is the same.

The vacuum tube section 1 includes a plurality of anode vanes 12 disposed on the inner surface of a circular cylindrical anode 11, an output conductor 13 extending from the anode vane 12, and both ends of the cylindrical anode 11. And the pole pieces 1 and 15
Flanges 16a, 1
7a, an insulating ring 18 sequentially provided on the eyelet tube 16 on the side of the output wire 13, and an output antenna 19 to which the end of the output wire 13 is electrically connected. And a pair of center leads 21a and side leads 21b provided at the end of the eyelet-shaped tube 17.
, A cathode filament 23 provided at the other end of the pair of center leads 21 a and the side leads 21 b, and a plurality of cooling tubes provided at the outer periphery of the cylindrical anode 11. And fins 24. The cathode filament 20 is formed by spirally forming a tungsten wire, and is formed by an end hat 10a provided at the other end of the center lead 21a and an end hat 10b provided at the other end of the side lead 21b. Is supported among them.

The magnetic circuit section 2 includes a cylindrical anode 1 of the vacuum tube section 1.
And ring-shaped magnets 22a, 22b arranged on both ends of
And iron yokes 25a and 25b surrounding the cylindrical anode 11 and the magnets 22a and 22b. Also,
The magnets 22a and 22b are made of a material such as ferrite or rare earth and Alnico (registered trademark).

[0013] The radio wave leakage prevention unit 3 includes a filter case 2
6, a cathode stem 23 having a pair of stem terminals 21
And a high-voltage capacitor 27 having a terminal 27 a provided on the filter case 26, and a pair of choke coils 28 provided between the stem terminal 21 and the terminal 27 a of the high-voltage capacitor 27.

In the magnetron device according to the present invention, one of the magnets 22a and 22b disposed at both ends of the cylindrical anode 11,
For example, the material or volume of the magnet 22b is made different.
In this embodiment, the magnet 22a and the magnet 22b are formed of the same material of ferrite, and the volume of the magnet 22b is set to 1.35 to 1.65 times the volume of the magnet 22a, so that the inside of the cylindrical anode 11 is reduced. The position where the temperature distribution of the cathode filament 20 is the highest and the position where the magnetic flux density distribution of the magnetic circuit portion 2 is the lowest at the position in the tube axis direction are substantially the same.

Next, the operation and effect of the magnetron device will be described.

The magnetron device of the present invention has a cylindrical anode 1
1, the cathode filament 20 at a position in the tube axis direction.
Is substantially the same as the position where the temperature distribution becomes the highest and the position where the magnetic flux density distribution of the magnetic circuit portion 2 becomes the lowest, so that the loss of electron motion in the cylindrical anode 11 is reduced,
Oscillation efficiency can be improved.

Further, since the magnets 22a and 22b arranged at both ends of the cylindrical anode 11 have different magnetic forces, after the vacuum tube 1 is manufactured, for example, the magnets 22b
Oscillation efficiency can be improved by a simple means that only varies the magnetic force of the magnetic field. As a result, an increase in the cost of the magnetron device can be minimized.

[0018]

Next, a description will be given of an embodiment in which the above effects of the present invention have been confirmed.

The magnetron device of the present invention uses the configuration shown in FIG. 1 and makes the magnetic force of one of the magnets 22a and 22b different, so that the magnetic force ratio of the magnet 22b / the magnet 22a (hereinafter, referred to as "magnet energy ratio") is zero. 9 to 2.0 and the oscillation efficiency, and in the magnet energy ratio, the temperature distribution of the cathode filament 20 and the magnetic flux density distribution of the magnetic circuit unit 2 at the position in the tube axis direction in the cylindrical anode 11 Were examined, the results shown in FIGS. 2 and 3 were obtained.

FIG. 2 shows the relationship between the magnet energy ratio and the oscillation efficiency. FIG. 2 shows that the magnet energy ratio is 1.35-1.
65 (equivalent to the present invention), the oscillation efficiency is improved, and the oscillation efficiency is 75% at a magnet energy ratio of 1.5.
And was the largest. Note that the oscillation efficiency at a magnet energy ratio of 1.0 (conventionally equivalent product) is 73%.

FIG. 3A shows the temperature distribution (curve A) of the cathode filament 20 and the magnetic circuit portion 2 at a position in the tube axis direction in the cylindrical anode 11 at a magnet energy ratio of 1.5.
FIG. 3A shows the relationship with the magnetic flux density distribution (curve B) of FIG.
Accordingly, the position Q where the temperature distribution of the cathode filament 20 is the highest and the position m where the magnetic flux density distribution of the magnetic circuit portion 2 is the lowest in the tube axial direction position in the cylindrical anode 11 are substantially the same. . From this, it is understood that the loss of the electron motion in the cylindrical anode 11 is reduced and the oscillation efficiency can be improved.

On the other hand, FIG. 3B shows a temperature distribution (curve C) of the cathode filament 20 and a magnetic flux of the magnetic circuit portion 2 at a position in the tube axis direction in the cylindrical anode 11 at a magnet energy ratio of 1.0. FIG. 3B shows the relationship with the density distribution (curve D). From FIG. 3B, the position Q where the temperature distribution of the cathode filament 20 is highest at the position in the tube axis direction inside the cylindrical anode 11 and the magnetic circuit portion 2 The position m where the magnetic flux density distribution is the lowest is shifted from the position m. The displacement occurs because the heat of the cathode filament 20 is released by heat conduction to the center lead 21a and the side lead 21b between the pole piece 15 and the cathode stem 23, so that the tube in the cylindrical anode 11 is dissipated. It is considered that the position Q at which the temperature distribution of the cathode filament 20 is highest in the axial direction is displaced from the center of the anode vane 12 (see FIG. 3) to the pole piece 14 side.

Therefore, the magnetron device according to the present invention has a structure in which the temperature distribution of the cathode filament 20 at the position Q in the tube axis direction in the cylindrical anode 11 is the highest.
By making the position m where the magnetic flux density distribution of the magnetic circuit portion 2 becomes minimum substantially the same, the loss of electron motion in the cylindrical anode 11 is reduced, and the oscillation efficiency, which has been limited to 73%, is reduced. It can be improved to 75%.

In the above embodiment, the cylindrical anode 11
The magnet 22a and the magnet 22b arranged at both ends of the above have been described by changing the material or volume of one of the magnets 22a and 22b, but the present invention is not limited to this, and the magnetic poles arranged at both ends of the cylindrical anode 11 are described. Magnetic materials having different magnetic forces by changing the material or volume of one of the pieces 14 and 15 or magnets having different magnetic force by changing the material or volume of one of the iron yokes 25a and 25b surrounding the magnets 22a and 22b are also applicable. it can.

[0025]

As described above, according to the present invention, the position where the temperature distribution of the cathode filament is highest in the position in the tube axis direction in the cylindrical anode and the position where the magnetic flux density distribution of the magnetic circuit portion is lowest are as follows. By making the positions substantially the same, the oscillation efficiency can be improved.

Further, since the magnets arranged at both ends of the cylindrical anode have different magnetic forces, the increase in cost of the magnetron device can be minimized, and the oscillation efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a magnetron device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a magnet energy ratio and an oscillation efficiency in the magnetron device.

FIG. 3 is a diagram showing a relationship between a temperature distribution of a cathode filament and a magnetic flux density distribution of a magnetic circuit unit in the magnetron device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum tube part 2 Magnetic circuit part 11 Cylindrical anode 20 Cathode filament 22a, 22b Magnet 25a, 25b Yoke

Continued on the front page (72) Inventor Takeshi Ishii 1-1, Sachimachi, Takatsuki-shi, Osaka, Japan Inside Matsushita Electronics Corporation (72) Inventor Takanori Handa 1-1, Sachimachi, Takatsuki-shi, Osaka, Matsushita Electronics Corporation F term (reference) 5C029 FF12

Claims (3)

[Claims] 1. A vacuum tube part having a cathode filament in a cylindrical anode, and magnets arranged on both ends of the cylindrical anode of the vacuum tube part, and a yoke surrounding the cylindrical anode and the magnet A position where the temperature distribution of the cathode filament is highest and a position where the magnetic flux density distribution of the magnetic circuit portion is lowest in the tube axial direction position in the cylindrical anode. And a magnetron device substantially identical to each other. 2. The magnetron device according to claim 1, wherein the magnets disposed at both ends of the cylindrical anode have different magnetic forces. 3. The magnetron device according to claim 2, wherein the magnetic force of the magnet is changed by changing a material or a volume.