JPS588537B2 - magnetron - Google Patents

Description

[Detailed description of the invention] The present invention relates to magnetrons.

Recently, magnetrons have been put into practical use that are made smaller and lighter by enclosing a small permanent magnet inside a vacuum container.

Since this magnetron has a structure in which the magnet is placed close to the working space on the tube axis, the output antenna terminal and the antenna feeder are protruded from the tube axis, which is the simplest structure.

However, since the output antenna terminal is offset from the tube axis, there is an inconvenience that the mounting method is limited when installing it in a microwave oven, etc., and the radiator that is attached to the outer periphery of the anode cylinder needs to be fixed in one direction. There are some inconveniences such as:

Therefore, an invention has already been proposed in which the output antenna terminal is aligned with the tube axis.

One of them is disclosed in Japanese Patent Application Laid-Open No. 50-147277, in which a space is created outside a magnetic end plate coupled to a permanent magnet on the output side, and an antenna feeder is mounted in a crank shape in this space. It is configured to be bent and connected to the antenna terminal on the tube axis.

However, this has the drawback that not only does the total length in the tube axis direction become long, but also the antenna feeder becomes unnecessarily long, making it difficult to match the load, and is therefore impractical.

Furthermore, the magnet disclosed in Japanese Utility Model Application Publication No. 53/2158 is one in which a permanent magnet is provided with an oblique cut groove or a through hole through which an antenna feeder passes.

However, this requires an extremely troublesome process of cutting grooves and through holes, and requires an increase in the amount of magnet material to be cut out, making it extremely impractical.

The present invention eliminates the drawbacks of the prior art as described above, and creates a magnetron in which the output antenna is positioned on the tube axis without increasing the total length in the tube axis direction and without performing complicated processing on the magnet. This is what we provide.

In other words, the feature is that a magnet structure consisting of a permanent magnet or a combination of a permanent magnet and a magnetic pole piece is arranged obliquely to the tube axis, and the antenna feeder is passed laterally along this magnet structure and placed on the tube axis. The antenna terminal is connected to the antenna terminal.

Examples thereof will be described below with reference to the drawings.

The embodiment shown in FIGS. 1 to 3 has the following structure.

An anode cylinder 11 made of a magnetic material such as soft iron has the function of a vacuum container, and one end is closed by a magnetic end plate 12, an output side sealing ring 13, and an output antenna terminal 14, and the other end is closed by a magnetic end plate 12, an output side sealing ring 13, and an output antenna terminal 14. It is closed by an end plate and a cathode input terminal (both not shown).

Inside this anode cylinder 11, a resonant cavity structure consisting of a highly conductive cylinder 15 such as copper and a large number of anode vanes 16 is provided, and an electron emitting cathode 17 is held on the tube axis C by a cathode lead 18. has been done.

The cathode lead 18 is fixed to a cathode input terminal (not shown).

An electron interaction space 19 is formed between the canard 17 and the anode vane 16 .

Therefore, in order to supply magnetic flux in a direction parallel to the tube axis to the working space 19, magnet assemblies 20, 20 are respectively arranged close to each other across the working space.

One magnet structure 20 consists of a cylindrical permanent magnet 22 and a ring-shaped magnetic pole piece 23 made of soft iron.
8 and is fixed by a retaining disk 24 which also serves as an end shield.

Now, the magnet structure 21 on the output side is obtained by cutting the cylindrical magnet material 25 diagonally at an angle other than 90° between the side surface and the magnetic pole faces 26a and 26b, as shown in FIG. 4 a+b. It is composed of a permanent magnet 26 and a disc-shaped magnetic pole piece 27 coupled to one end surface 26a of the permanent magnet 26.

The magnetic pole face 27a of the magnetic pole piece 27 has a recess in the center.

One cut surface 26a of the magnet 26 and the magnetic pole piece 2γ, that is, the magnetic pole face of this magnet structure, are aligned with the tube axis C, and the other cut surface 26b, that is, the magnetic pole surface of the magnet structure is positioned closer to the rock in the figure than the tube axis C. It is located offset to the side and is coupled to the magnetic end plate 12.

In this way, the magnet assembly 21 is arranged so that its longitudinal direction is substantially oblique to the tube axis C.

This magnet structure S1 is mechanically held and fixed by a press-molded projection 28 for positioning provided on the end plate 12 and a holding disc 29 which also serves as an end shield.

The antenna terminal 14 is positioned in line with the tube axis C,
It protrudes outward through a dielectric cylinder 30 and a sealing ring 13 that covers the end plate 12 and is hermetically sealed to the end of the anode cylinder 11 .

A conductive gasket ring 31 is provided on the outer periphery of the sealing ring 13.
is fitted.

The magnetic end plate 12 and the holding disk 29 each have a through hole 12a.
, 29a are formed, and the output antenna feeder 32 is arranged through these through holes.

One end of this antenna feeder 32 is coupled to a part of the resonant cavity, that is, near the outer end of the anode vane, an intermediate part 32a is guided laterally along the magnet structure 21, and the other end is connected to a tube. The antenna terminal 14 is extended in line with the axis C.
is combined with

The magnet assemblies 20 and 21, assembled as described above, are simultaneously magnetized by a parallel magnetic field in the direction of the tube axis.

Furthermore, a heat dissipation fin 33 is provided on the outer periphery of the anode cylinder 11.
is fixed.

In the above-described magnetron of the present invention, the output side magnet structure is arranged substantially obliquely to the tube axis, and the antenna feeder is led out along this and coupled to the antenna terminal on the tube axis. A magnetron having an antenna terminal aligned with the tube axis can be realized without increasing the total length in the tube axis direction.

This eliminates the need to make the antenna feeder undesirably long, and does not cause problems in matching characteristics with the load or high frequency losses.

Further, as shown in FIG. 4, the permanent magnet can be constructed by only a very simple cutting process, and does not impede workability or the efficiency of magnet material utilization.

In this way, it is extremely practical.

In the embodiment shown in FIGS. 5 and 6, the magnetic pole face 2 of the magnet 26 is
The shape of the magnetic pole piece 27 connected to 6a is made thicker on the corner 26c side, which is the small cutting angle of the magnet, so that the magnetic pole face 27 is tapered.
It is designed to form a.

As a result, the magnetic flux in the working space 19 is corrected so that it becomes more parallel to the tube axis.

Of course, the angle and surface shape of the tapered surface 27a can be designed to provide the best oscillation characteristics.

In the embodiment shown in FIG. 7, the magnet structure 21 includes a cylindrical permanent magnet 26 whose cut surface is at a right angle θ, magnetic pole pieces 27 with one surface tapered on both sides of the magnet, and a magnetic conductive material 41.
(Both are made of a magnetic material such as soft iron) bonded together.

Also in this case, one magnetic pole surface of the magnet structure 21, that is, the magnetic pole surface 27a facing the working space of the magnetic pole piece 270, is aligned with the tube axis C,
The end plate 1 is moved by shifting the other magnetic pole surface, that is, the back surface of the magnetic conductor 41 to the side opposite to the position of the antenna feeder 32 with respect to the tube axis.
It is combined into 2.

In this embodiment, the permanent magnet can be made into the simplest disk shape, so a lower cost magnet can be used.

In the embodiment shown in FIG. 9, the magnetic conductive body 41 shown in FIG. 7 is not used, and the magnetic end plate 12 itself is extruded obliquely from the back side to form an oblique magnet coupling portion 42.

This does not increase the magnetic resistance in the magnetic closed circuit, does not involve much difficulty in machining, and is easy to assemble, making it highly practical.

The embodiments shown in FIGS. 10a, b, and c relate to the shape of a permanent magnet, and as shown in FIG. Alternatively, 26b) is cut by setting an angle θ between the side surface in the short axis direction of the ellipse and the cut surface, that is, the magnetic pole surface, so that the planar shape of 26b is a perfect circle as shown in FIG.

This allows the magnetic pole surface of the permanent magnet to be made into a perfect circle, and since the long axis direction of this magnet is perpendicular to the antenna feeder, the magnetic pole surface can be made into a perfect circle without reducing the distance between the antenna feeder and the magnet. The cross-sectional area of the magnet can be increased to increase the force, and therefore a magnet with a short axial length and a large volume can be used.

In addition, in the present invention, the magnet structure may be composed of only permanent magnets, and the permanent magnets may be cylindrical or polygonal in cross section, or may be made of metal such as alnico magnets. In addition to magnets, it is also possible to use compression-molded powder such as Ceraminok magnets.

Further, the center of the magnetic pole face facing the working space is not limited to a case where it completely coincides with the tube axis, but it is naturally possible to have a case where the center is slightly deviated from the tube axis.

As described above, the present invention can realize a magnetron in which the tube axis and the antenna terminal axis are aligned without increasing the overall length of the magnetron.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing one embodiment of the present invention, Fig. 2 is a transverse sectional view taken at 2-2 in Fig. Figures illustrating a method of forming a magnet; Figure 5A is a top view, Figure 5B is a side view, Figure 5 is a cross-sectional view of main parts showing another embodiment of the present invention, and Figure 6 is a perspective view showing the magnetic pole pieces. 7 is a sectional view of a main part showing still another embodiment of the present invention, FIG. 8 is a perspective view showing the magnet, FIG. 9 is a sectional view of a main part showing still another embodiment, and FIG. The figure is a diagram showing the magnet shape and its formation method in another embodiment.
is a top view, b is a side view, and b is a side view. is a developed view of the cut surface. 11...Anote 5 cylinder, 12...
...Magnetic end plate, 16...Anode vane, 17
...Cathode, 14...Output antenna terminal, 32...Antenna feeder, 20.21
...Magnet structure, C...Tube shaft, 26...
...Permanent magnet, 27...Magnetic pole piece, 26a,
26b, 27a...Magnetic pole surface.

Claims (1)

[Claims] 1. A magnet structure including a permanent magnet disposed close to the working space between the cathode and the anode vane, a magnetic end plate connected to the outer magnetic pole surface of the magnet structure, and a magnetic end plate connected to the outer magnetic pole surface of the magnet structure. an antenna terminal provided on the tube axis outside the magnetic end plate;
An antenna feeder is provided to connect the resonant cavity made of the anode vane and the antenna terminal, and the magnet structure has one magnetic pole surface facing closely to the working space on the tube axis, and the other magnetic pole surface facing closely to the working space. The antenna feeder is connected to the magnetic end plate with its surface shifted from the tube axis to the side opposite to the position of the antenna feeder, and is arranged substantially obliquely to the tube axis, and the antenna feeder is located on the side of the magnet structure. The magnetron is connected to the above antenna terminal through the antenna terminal. 2. The magnet structure has a columnar or cylindrical permanent magnet whose magnetic pole surface is inclined with respect to the side surface.
Magnetron described in section. 3. The magnet structure according to claim 1, wherein the magnet structure includes a columnar or cylindrical permanent magnet having a magnetic pole surface perpendicular to the side surface, and a tapered magnetic pole piece coupled to the magnetic pole surface of this magnet. Magnetron 4 The magnet structure is a permanent magnet made of a columnar or cylindrical magnet material whose outer periphery is generally elliptical, and has a magnetic pole surface that is inclined with respect to the side surface in the short axis direction so that the magnetic pole surface is circular. A magnetron according to claim 2 comprising: