JP2001332180A - Magnetron - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easy-to-produce magnetron capable of keeping the characteristics of a cavity resonator as desired which changes when miniaturized with the smaller diameter of a cylindrical anode. SOLUTION: The magnetron comprises adjacent vanes 2a protruded from the inner periphery face of the cylindrical anode 1 and the cavity resonator R having predetermined characteristics, formed in a space encircled by the inner periphery face of the cylindrical anode 1. Each vane 2a is arranged in inclination to the direction of the diameter of the cylindrical anode 1 corresponding to the smaller diameter of the cylindrical anode 1.

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 heating device such as a microwave oven, a radar, and the like, and more particularly to an anode structure thereof.

[0002]

2. Description of the Related Art Generally, a magnetron anode is shown in FIG.
It is configured as shown in FIG. That is, a cathode portion (filament) (not shown) is provided on the inner peripheral surface of the cylindrical anode body 1.
Are arranged toward the center axis where
Zero vanes 2 are radially arranged, and a cavity resonator R is formed by a space surrounded by two adjacent vanes 2 and the inner peripheral surface of the cylindrical anode body 1. Large and small straps 3 and 4 for connecting the vanes 2 to each other are attached to the upper and lower inner peripheral sides of each vane 2.

As these anode materials, expensive oxygen-free copper or equivalents are used so as to withstand repeated use as vacuum tubes at high temperatures. In particular, since the cylindrical anode body 1 occupies 70 to 80% of the amount of oxygen-free copper used in the magnetron, reducing the diameter of the cylindrical anode body 1 reduces the size and weight of the magnetron and the cost of raw materials. Is desirable.

[0004]

As described above, the length of the vanes 2 protruding from the inner peripheral surface of the cylindrical anode body 1, that is, the length in the radial direction is reduced to reduce the diameter of the cylindrical anode body 1. Attempts have been frequently made to reduce the diameter of the unit cavity resonator R shown in FIG. 5 because the creepage length l of the unit cavity resonator R shown in FIG. The resonance frequency of the resonator R (24 in the case of a microwave oven)
50 MHz), and the original characteristics cannot be obtained.

Japanese Patent Application Laid-Open No. 11-167876 (H01J 23/20) discloses that the area of the opposing surface of an adjacent vane is larger than that of a flat vane parallel to the axial direction of the cylindrical anode body as described above. It is disclosed that a curved surface or an inclined surface is formed with respect to an axial direction so as to have a large area.

However, in the configuration disclosed in the above-mentioned publication, the joint portion is complicated because the vane itself is processed into a curved surface shape or the vane is joined to the curved surface direction of the inner peripheral surface of the cylindrical anode body without any gap. Since it must be processed into a curved shape and carefully joined together, it is not easy to manufacture.

Accordingly, the present invention has been made to solve such a problem, and the characteristics of the cavity resonator, which changes when the size of the cylindrical anode body is reduced due to a reduction in the diameter or the like, is changed to a desired characteristic. It is an object of the present invention to provide a magnetron that can be maintained at a low temperature and that can be easily manufactured.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a method of forming a cylindrical anode body, comprising: an adjacent vane projecting from an inner peripheral surface of the cylindrical anode body; In a magnetron in which a cavity is formed in a space surrounded by a surface, the vanes are arranged to be inclined with respect to the radial direction of the cylindrical anode body.

Further, a cavity resonator having predetermined characteristics is formed in a space surrounded by adjacent vanes of each vane projecting from the inner peripheral surface of the cylindrical anode body and the inner peripheral surface of the cylindrical anode body. In the above magnetron, each of the vanes is arranged in an inclined shape with respect to the radial direction of the cylindrical anode body in accordance with the degree of diameter reduction of the cylindrical anode body.

Further, the tip surface of each of the inclined vanes is formed so as to face the center of the cylindrical anode body.

Further, the present invention is characterized in that the cylindrical anode body and each of the vanes arranged obliquely with respect to the radial direction are integrally formed by punching.

[0012]

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

FIG. 1 is a plan view showing an anode part of the present embodiment,
FIG. 2 is an explanatory view of the unit cavity resonator, and FIG. 3 is a longitudinal half sectional view showing the entire configuration of a magnetron for a microwave oven to which the present embodiment is applied. The same reference numerals as those in FIGS. The corresponding part is shown.

In the present embodiment, as shown in FIG. 1, each of the vanes 2a disposed on the inner peripheral surface of the cylindrical anode body 1 has a diameter corresponding to the diameter of the cylindrical anode body 1. It is arranged in an inclined shape according to the degree of miniaturization. The cavity resonator R is formed by a space surrounded by the two vanes 2 a which are arranged adjacent to each other in an inclined manner and the inner peripheral surface of the cylindrical anode body 1. Large and small straps 3, 4 connecting the vanes 2a every other one above and below the inner peripheral side of each vane 2a.
Is attached. Further, the tip surface 2b of each of the vanes 2a arranged in an inclined manner is formed so as to face the center direction of the cylindrical anode body 1.

Most of the microwave current flowing through the vane 2a constituting the cavity resonator R and the inner peripheral surface of the cylindrical anode body 1 is concentrated on the surface by the skin effect. According to the present embodiment, at this time, since the microwave current flows along the surface of the vane 2a which is arranged inclined with respect to the radial direction, the electrical length of the microwave is obtained with a smaller diameter than the conventional shape. be able to. In other words, the inductance L of the unit cavity resonator R, which is reduced due to the reduction in the diameter of the cylindrical anode body 1, is perpendicular to the inner peripheral surface of the conventional cylindrical anode body 1 by the vanes 2 a arranged inclined with respect to the radial direction. It can be equivalent to Vane 2.

As a result, the characteristics of the cavity resonator R, which change when the size is reduced, can be maintained as in the prior art, and the size and weight of the magnetron can be reduced, and the cost of raw materials can be reduced.

Further, since each of the vanes 2a does not need to be inclined in the axial direction of the cylindrical anode body 1 while remaining in a flat plate shape, the vanes 2a themselves may be processed into a curved surface shape or the inside of the cylindrical anode body 1 may be formed. Since there is no need to process the joint portion with the peripheral surface into a complicated curved surface shape, manufacture is easy.

Further, as described above, since each vane 2a does not need to be inclined in the axial direction of the cylindrical anode body 1 while being in the form of a flat plate, punching can be performed. If the vanes 1a and the vanes 2a arranged obliquely with respect to the radial direction are integrally formed by punching, the production can be further facilitated.

Furthermore, each vane 2a arranged in an inclined manner
Is formed so as to face the center direction of the cylindrical anode body 1, the working space can be kept substantially coaxial, so that stable oscillation is not impaired.

As shown in FIG. 3, the central axis of the cylindrical anode body 1 of the anode portion constructed as described above is arranged in a space (working space) surrounded by each vane 2a. The filament 5 which is installed in the direction and constitutes the cathode part is arranged. The filament 5 has both ends supported by end leads 6 and 7.

As described above, large and small straps 3 and 4 for connecting the vanes 2a to each other are attached to the upper and lower sides of the inner periphery of each vane 2a, and one of the vanes 2a has an antenna. The conductor 8 is connected.

Magnetic pole pieces 9 and 10 are arranged on the output side and the cathode side of the cylindrical anode body 1, respectively. The pole piece 9 on the upper side in the figure is provided with a through hole 9a through which the antenna conductor 8 passes. Have been. At the upper end of the cylindrical anode body 1, a top shell 11 which is a sealing metal fixed to the cylindrical anode body 1 with the magnetic pole piece 9 interposed therebetween is provided. A stem metal 12 which is a sealing metal fixed to the sandwiching tubular anode body 1 is provided.

At the upper end of the top shell 11, an output-portion-supporting antenna ceramic 13 is fixedly attached by brazing, and an output pipe 14 fixed to the antenna ceramic 13 and joined to the antenna conductor 6 is provided. ing. An antenna cap 15 is press-fitted into the output pipe 14. On the other hand, a stem ceramic 16 for supporting the end leads 6 and 7 is fixed to the stem metal 12. Thus, a two-pole vacuum tube of the magnetron is formed.

Annular magnets 17 and 18 are arranged above and below the cylindrical anode body 1, respectively, and cooling fins 19 are attached to the outer peripheral surface of the cylindrical anode body 1. The cylindrical anode body 1, the annular magnets 17, 18 and the cooling fins 19 are surrounded by a yoke 20, and a lower part of the yoke 20 surrounds a stem ceramic 16 protruding from the yoke 20, and a shield case incorporating a filter circuit 21. 22 are provided. A gasket 23 is provided on the upper surface of the yoke 20 so as to be in close contact with the joint of the microwave oven. A gasket ring 24 holding the gasket 23 is press-fitted into the top shell 11.

In the above configuration, the filaments 5 and 1
Microwaves are generated in a space (action space) between the zero vane 2a and propagate through the antenna conductor 8 from the vane 2a,
The light is radiated from the output pipe 14 through the antenna cap 15 to the space inside the microwave oven. In the working space, a microwave is generated by applying a magnetic field perpendicular to the electric field.

Next, the operation of the present embodiment will be described in more detail using the unit cavity resonator R in the magnetron of the present embodiment shown in FIG.

Considering the cavity resonator R as an LC equivalent circuit, the creepage length l of the pair of vanes 2a and the inner peripheral surface of the cylindrical anode body 1 is equal to the inductance L, and the distance between the vanes 2a and the strap 3 , 4 and between the straps 3, 4 and the vane 2a correspond to the capacitance C.

As shown in FIG. 5, the conventional cavity resonator has
The vanes 2 are radially arranged from the inner peripheral surface of the cylindrical anode body 1 toward the central axis, and the creepage length l is the creepage length of the pair of vanes 2 and the inner peripheral surface of the tubular anode body 1 itself.

On the other hand, in the present embodiment, the vanes 2a are arranged obliquely with respect to the radial direction from the inner peripheral surface of the cylindrical anode body 1 in accordance with the degree of diameter reduction of the cylindrical anode body 1. Therefore, the microwave current flowing on the surface due to the skin effect flows along the shape of the vanes 2a arranged in an inclined manner, and it is possible to compensate for the creeping length 1 reduced by the reduction in the diameter of the cylindrical anode body 1. Become.

As a result, the characteristics of the cavity resonator R, which change when the size of the cylindrical anode body 1 is reduced due to a reduction in diameter or the like, can be maintained as in the prior art.

[0031]

As described above, according to the present invention, cavity resonance occurs in a space surrounded by adjacent vanes of each vane projecting from the inner peripheral surface of the cylindrical anode body and the inner peripheral surface of the cylindrical anode body. In the magnetron formed by forming a vessel, by arranging each vane obliquely to the radial direction of the cylindrical anode body,
Since the anode portion such as a cylindrical anode body can be downsized with respect to the characteristics of the cavity resonator, it is possible to contribute to space saving and resource saving such as downsizing and weight reduction of magnetron and reduction of raw material cost. In addition, since each vane does not need to be inclined in the axial direction of the cylindrical anode body while maintaining the flat shape, the vane itself may be processed into a curved shape, or a joint portion with the inner peripheral surface of the cylindrical anode body may be formed. Since it is not necessary to work on a complicated curved surface shape, manufacture is easy.

Further, a cavity resonator having predetermined characteristics is formed in a space surrounded by adjacent vanes of each vane projecting from the inner peripheral surface of the cylindrical anode body and the inner peripheral surface of the cylindrical anode body. In the magnetron, each vane is fixedly determined, particularly in a microwave oven or the like, by arranging each vane in an inclined shape corresponding to the degree of diameter reduction of the cylindrical anode body with respect to the radial direction of the cylindrical anode body. Since the anode part such as a cylindrical anode body can be downsized while maintaining the characteristics of the cavity resonator, space saving such as downsizing and weight reduction of magnetron and cost reduction of raw materials can be achieved.
Contribute to resource saving. Further, similarly to the above, since each vane does not need to be inclined in the axial direction of the cylindrical anode body while being in a flat shape, the vane itself may be processed into a curved shape, or may be formed with the inner peripheral surface of the cylindrical anode body. Since it is not necessary to process the joint portion into a complicated curved shape, manufacture is easy.

Furthermore, since the tip end surface of each of the vanes arranged in an inclined manner is formed so as to face the center of the cylindrical anode body, the working space can be kept substantially coaxial. Also, stable oscillation is not impaired.

Further, as described above, since each vane does not need to be inclined in the axial direction of the cylindrical anode body while being in a flat plate shape, punching can be performed. If the vanes arranged obliquely with respect to the radial direction are integrally formed by punching, the production can be further facilitated.

[Brief description of the drawings]

FIG. 1 is a plan view showing an anode section of a magnetron according to an embodiment of the present invention.

FIG. 2 is an explanatory view of the unit cavity resonator of FIG. 1;

FIG. 3 is a longitudinal half sectional view showing the entire configuration of a magnetron for a microwave oven to which the embodiment is applied.

FIG. 4 is a plan view of a conventional anode unit.

FIG. 5 is an explanatory diagram of the unit cavity resonator of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical anode body 2, 2a Bain 2b Tip surface 3, 4 Strap 5 Filament 6, 7 End lead 8 Antenna conductor 9, 10 Magnetic pole piece 11 Top shell 12 Stem metal 13 Antenna ceramic 14 Output pipe 15 Antenna cap 16 Stem ceramic 17 , 18 Ring magnet 19 Cooling fin 20 Yoke 21 Filter circuit 22 Shield case 23 Gasket 24 Gasket ring R Cavity resonator l Creepage length

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Noriyuki Murao 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Kazuki Miki 2-5-5 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Inventor Setsuo Hasegawa 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. 5C029 KK05 LL02

Claims (4)

[Claims] 1. A magnetron comprising: a cavity formed by a space surrounded by adjacent vanes of each vane projecting from an inner peripheral surface of a cylindrical anode body and an inner peripheral surface of the cylindrical anode body; A magnetron, wherein each vane is arranged inclined with respect to the radial direction of the cylindrical anode body. 2. A cavity resonator having predetermined characteristics is formed in a space surrounded by adjacent vanes of each vane projecting from the inner peripheral surface of the cylindrical anode body and the inner peripheral surface of the cylindrical anode body. The magnetron according to claim 1, wherein each of the vanes is arranged in an inclined shape with respect to a radial direction of the cylindrical anode body according to a degree of diameter reduction of the cylindrical anode body. 3. The magnetron according to claim 1, wherein a tip end surface of each of the inclined vanes is formed so as to face a center direction of the cylindrical anode body. 4. The method according to claim 1, wherein the cylindrical anode body and each of the vanes arranged obliquely with respect to the radial direction are integrally formed by punching. Magnetron.