JPH1055761A - Magnetron - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform stable oscillation for a long time by forming a magnetron in which a getter having an opening part is disposed at a central part of an anode cylinder or a magnetic pole piece. SOLUTION: When a magnetron operates, a filament 6 is heated to approx. 1,700 deg.C, and a magnetic pole piece 5 is heated to approx. 300 deg.C by transmission heat. At this time, a getter 19 is heated to approx. 300 deg.C by the magnetic pole piece 5. While in operation, microwaves are generated in an actuation area, and the microwaves spreads on a surface of the magnetic pole piece 5 by surface skin effect. The surface of the magnetic pole piece 5 is plated by copper or nickel, and its resistance rate is approx. 10%, of the getter 19. In an aspect of this embodiment, since the circular getter 19 is arranged over an opening at the center of the magnetic pole piece 5, the getter 19 exists over the microwave spreading direction, and microwaves propagating on the surface of the magnetic pole piece 5 pass through the getter 19. Thus, stable oscillation of the magnetron is performed over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron used for a microwave heater such as a microwave oven.

[0002]

2. Description of the Related Art FIG. 3 shows a structure of a conventional general magnetron. Reference numeral 1 denotes an anode cylinder which is made of oxygen-free copper or the like and becomes a part of a vacuum wall (the wall surface of a vacuum vessel, the same applies hereinafter), and a plurality of vanes 2 are radially provided on the inner periphery thereof. Every other vane 2 is connected by a large and small diameter strap ring 3 to stabilize π mode oscillation. At both ends of the anode cylinder 1, pole pieces 5 for concentrating a magnetic field in an action space between the tip of the vane 2 and the cathode 4 provided at the center of the anode cylinder 1 are provided.

The cathode 4 is composed of a filament 6 in which, for example, a thorium tungsten wire is wound in a coil shape, and is provided in the center of the anode cylinder 1 in a space surrounded by the tip of each vane 2. And top hat 7 at both ends
And the end hat 8 are fixed, and the top hat 7 and the end hat 8 are respectively connected to the cathode leads 9. The cathode lead 9 is connected to an external lead 11 via a cathode stem 10 made of an insulator such as ceramic, and these form a cathode portion. The cathode stem 10 is fixed to the anode cylinder 1 via the cathode side metal cylinder 12. In addition,
The cathode side metal tube 12 and the cathode stem 10 constitute a vacuum wall on the input side.

One of the vanes 2 has an output antenna lead 1
The other end is electrically connected, and the other end passes through the central portion of the through-hole 14 of the pole piece 5, the output-side metal tube 15, the insulating tube 16 made of a ceramic cylinder or the like, and is a sealed portion of the exhaust pipe 17. Fixed. A cap (not shown) is placed over the sealing portion. The output side metal tube 15 is directly electrically connected to the anode cylinder 1, and the microwave power oscillated at the anode portion travels as a coaxial line with the output antenna lead 13 extending on the central axis of the output side metal tube 15, Radiated from its tip. The output-side metal tube 15, the insulating tube 16, and the exhaust pipe 17 constitute a vacuum wall on the output side.

[0005] A getter 18 is joined to the upper surface of the top hat 7 of the filament 6 to adsorb a small amount of gas generated in the tube. The getter 18 is made of titanium, zirconium, or the like. The getter 18 makes the oscillating portion of the magnetron a high vacuum and maintains stable oscillation.

[0006]

However, during operation of the magnetron, the temperature of the filament becomes high, and accordingly, the temperature of the top hat and the end hat becomes high. At this time, the fermentation reaches about 1700 ° C., and the getter joined to the top hat is also heated to a high temperature of about 1100 ° C. As described above, since the getter operates at a high temperature, there is a problem that the getter is plastically deformed when used for a long time.

In view of this, a configuration is conceivable in which the getter is provided on a pole piece or an anode cylinder operating at a low temperature instead of the top hat. However, since the pole piece and the anode cylinder are mainly heated by conduction heat, there is a problem that the temperature does not rise so much during the operation time actually used at home. Therefore, the getter may not be heated to a temperature at which the gas is well absorbed, and may not be able to absorb the gas in the magnetron. When the degree of vacuum in the magnetron decreases, oscillation efficiency decreases, and when the degree of vacuum further decreases, oscillation may be stopped.

Accordingly, the present invention provides a magnetron that suppresses a decrease in the degree of vacuum and performs stable oscillation.

[0009]

In order to solve the above-mentioned problems, the invention according to claim 1 includes an anode cylinder, a cathode arranged on the center axis of the anode cylinder, and a radial arrangement on the inner peripheral surface of the anode cylinder. And a pair of pole pieces disposed at both open ends of the anode cylinder.
A getter having an opening in the center is provided on the anode cylinder or the pole piece. When the magnetron operates, microwaves propagate by the skin effect on the surfaces of the anode cylinder and the pole piece. Since the getter has a closed loop shape, the getter exists in the microwave propagation direction, and the microwave passes through the getter. Therefore, the getter generates heat by itself and the operating temperature of the getter increases.

[0010] The invention according to claim 2 provides an anode cylinder, a cathode arranged on the center axis of the anode cylinder, a plurality of vanes radially arranged on the inner peripheral surface of the anode cylinder, and both of the anode cylinder. A magnetron including a pair of pole pieces disposed at an open end. An annular getter is provided on the pole piece. When the magnetron operates, the microwave propagates to the pole piece by a skin effect, passes through the getter, and self-heats the getter.

[0013] The invention according to claim 3 is characterized in that the anode cylinder, the cathode disposed on the center axis of the anode cylinder, a plurality of vanes radially arranged on the inner peripheral surface of the anode cylinder, and the anode cylinder A magnetron including a pair of pole pieces disposed at an open end. An annular getter is disposed on the inner surface of the anode cylinder. When the magnetron operates, the microwave propagates to the anode cylinder by a skin effect, passes through the getter, and the getter generates heat.

[0012]

An embodiment of the present invention will be described with reference to FIG. In addition, the same components as those in the related art are denoted by the same reference numerals, and description thereof is omitted.

In FIG. 1, reference numeral 19 denotes a getter provided on the pole piece 5, which is made of titanium, zirconium or the like. The getter 19 is formed in an annular shape, and its size is larger than the opening formed in the center of the pole piece 5. The getter 19 is attached along the periphery of the central opening of the pole piece 5.

When the magnetron operates, the fermenter 6 generates heat to about 1700 ° C., and the pole piece 5 is heated to about 300 ° C. by conduction heat. At this time, the getter 19 is heated to about 300 ° C. by the pole piece 5. During operation, a microwave is generated in the working space, and the microwave propagates on the surface of the pole piece 5 due to the skin effect. The surface of the pole piece 5 is plated with copper or nickel, and its resistivity is about 10% of that of the getter 19. In general, if there is a portion without the getter 19 in the microwave propagation direction, the microwave concentrates on that portion, and the microwave hardly flows on the surface of the getter 19. However, in this embodiment, since the annular getter 19 is provided along the central opening of the pole piece 5, the getter 19 exists in the microwave propagation direction and propagates on the surface of the pole piece 5. The passing microwave passes through the getter 19. And since the getter 19 generates self-heating,
The temperature of the getter 19 becomes higher than 300 ° C., and the gas absorption rate becomes faster.

The getter 19, which has generated heat, absorbs the gas generated from the vacuum tube components of the magnetron, and maintains a vacuum state in the magnetron. Therefore, the magnetron can oscillate stably for a long time.

FIG. 2 shows another embodiment. The same parts as those in the embodiment of FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 20 denotes a getter, which is provided on the anode cylinder 1. The getter 20 is made of titanium, zirconium, or the like, similarly to the getter 19 of FIG. Getter 20
Has an annular shape and is large enough to fit into the inner surface of the anode cylinder 1. This getter is large enough to abut the inner surface of the anode cylinder 1 without any gap, so that a getter 20 larger than the getter 18 provided in the top hat 7 can be provided as in the conventional case, and a large amount of gas in the magnetron can be absorbed. Can be.

When the magnetron operates, the fermenter 6 generates heat, and the conduction heat causes the anode cylinder 1 to move about 300 mm.
° C. The getter 20 is heated by the anode cylinder 1 to about 300
° C. When a microwave is generated from the working space, the microwave propagates on the surface of the anode cylinder 1 by a surface effect. Since the getter 20 is disposed over the inner surface of the anode cylinder 1, the microwave propagating on the anode cylinder 1 passes through the getter 20, and the getter 20 generates heat. At this time, the temperature of the getter 20 becomes higher than 300 ° C., and the getter 20 efficiently absorbs gas.

When the magnetron operates and the temperature inside the vacuum section becomes high, gas is generated from the components inside the vacuum section. This gas is absorbed by the getter 20, and the inside of the vacuum section is kept in a vacuum state. The getter 20 has a higher temperature than 300 ° C., but has a lower temperature than the getter 18 (about 1100 ° C.) provided in the top hat 7 as in the conventional case. Therefore, the getter 20 deteriorates slowly and can absorb gas for a long period of time. Furthermore, since a larger getter 20 can be disposed than disposed on the top hat 7,
Many gases can be absorbed, and the inside of the magnetron can be kept in a vacuum state for a long time.

The getter of the present invention only needs to have a configuration in which microwaves pass, and it is sufficient that the getters exist in the microwave propagation direction. Therefore, a closed-loop getter having an opening at the center may be used, and its shape may be a rectangle or a triangle. When the getter is disposed such that the entire bottom surface thereof is in contact with the inner surface of the anode cylinder 1, the anode cylinder 1 exists at the opening and the outer periphery of the getter. Therefore, when the magnetron operates, the microwave passes through the getter and the getter generates heat.

[0021]

According to the first aspect of the present invention, a getter having an opening in the center is provided on the anode cylinder or the pole piece.
Therefore, since the getter exists in the propagation direction of the microwave, the microwave passes through the getter during the operation of the magnetron. The getter self-heats and raises the operating temperature, so that the getter absorbs gas well and can maintain a vacuum state in the magnetron.

According to the second aspect of the present invention, the magnetic pole piece is provided with an annular getter. Then, during operation of the magnetron, microwaves propagating on the surface of the pole piece pass through the getter, and the getter self-heats and absorbs gas well. In addition, since the getter is disposed near the operation region of the magnetron, the gas in the operation region can be efficiently absorbed.
Therefore, the inside of the magnetron can be maintained in a vacuum state, and stable oscillation can be performed for a long time.

According to the third aspect of the present invention, an annular getter is provided on the inner surface of the anode cylinder. During operation of the magnetron, microwaves propagating on the surface of the anode cylinder pass through the getter, and the getter self-heats and absorbs gas well. Further, since there are many places where getters are provided in the anode cylinder, a large getter can be provided and a large amount of gas can be absorbed. Therefore, the inside of the magnetron can be maintained in a vacuum state, and stable oscillation can be performed for a long time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main body according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main body showing another embodiment of the present invention.

FIG. 3 is a sectional view of a main body of a conventional magnetron.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode cylinder 2 Bain 4 Cathode 5 Magnetic pole piece 7 Top hat 8 End hat 19 Getter 20 Getter

Claims (3)

[Claims] 1. An anode cylinder, a cathode arranged on a central axis of the anode cylinder, a plurality of vanes radially arranged on an inner peripheral surface of the anode cylinder, and both open ends of the anode cylinder. And a pair of magnetic pole pieces disposed on the anode cylinder or the pole piece, and a getter having an opening in the center of the magnetic pole piece. 2. An anode cylinder, a cathode arranged on a central axis of the anode cylinder, a plurality of vanes radially arranged on an inner peripheral surface of the anode cylinder, and both open ends of the anode cylinder. And a pair of magnetic pole pieces disposed on the magnetic pole piece, and an annular getter is disposed on the magnetic pole piece. 3. An anode cylinder, a cathode disposed on a center axis of the anode cylinder, a plurality of vanes radially arranged on an inner peripheral surface of the anode cylinder, and both open ends of the anode cylinder. And a pair of magnetic pole pieces disposed on the inner surface of the anode cylinder.