JPS588536B2 - magnetron - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetron, and more particularly to an improvement in the magnet mounting structure thereof.

A general magnetron has a structure as shown in FIG.

That is, an oscillating unit main body comprising a cathode 11, an anode vane 12, a cylindrical anode body 13, pole pieces 14, 15, a cathode stem 16, and an output antenna 17; a cylindrical permanent magnet 19, 20, a magnetic yoke 21 surrounding them and forming a magnetic circuit;
22, screws 23, 24 which tightly tighten these two yokes 21, 22 together and serve as means for attaching the magnetron, and a heat sink 25 fixed to the outer periphery of the anode body.

In such a magnetron, the permanent magnet is sandwiched between the main body and the yoke, and is mechanically fixed by the strong clamping force between the two.

However, although such a magnet fixing structure is practical when the magnet itself is mechanically strong, it cannot be used when the magnet is relatively fragile, such as the rare magnets that have been developed recently.

This is because the clamping force between the main body and the yoke applies undesirable stress to the magnet, and in extreme cases there is a risk that it may crack.

The present invention provides a magnetron having a structure that allows stable operation without applying undesirable stress to the magnet.

In other words, its feature is that a magnetic yoke is firmly fixed to the oscillating unit body, and the permanent magnet is held in this yoke so that it can be attached to a specified position without applying large mechanical stress to the magnet. It is.

A hanging magnet is held in such a manner that it is simply suspended from a yoke.

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

The embodiment shown in FIGS. 2 and 3 has the following structure.

The oscillating unit main body 30 includes a cylindrical anode body 31 and an anode vane 32.
, a cathode 33, a cathode stem 34 that holds the cathode, an output antenna 35, and non-magnetic sealing bodies 36 and 37 that airtightly seal the openings at both ends of the anode body.

An electron action space 38 is formed between the cathode 33 and the anode vane 32 .

Therefore, a U-shaped magnetic yoke 39 is mechanically fixed to the outer periphery of the anode body 31 by welding or the like.

A flat magnetic yoke is coupled to the end of the yoke 39.

Then, outside the vacuum region of the main body 30, a cylindrical permanent magnet 4 is placed coaxially with the central axis of the main body and close to the electron action space.
1.42 are mechanically held on the yokes 39, 40, respectively, by cylindrical holders 43, 44 made of a non-magnetic material such as aluminum.

In addition, inner concave pole pieces 45 and 46 are fixed to the outer sides of the sealing bodies 36 and 37 of the main body, respectively, corresponding to the electronic action space.

There is a slight distance between the magnet 4L 42 and the main body,
The magnet is held in such a way that a narrow air gap 47.47 is provided here.

The cylindrical obliterator 44 is provided with a collar 48 to which a magnet is secured at one end, and a plurality of protrusions 4 at the other end.
9, 49, . . . are provided, and with the magnet housed inside, the magnet is passed through a through hole provided in the yoke, bent and twisted, and fixed to the yoke.

The yokes 39 and 40 are magnetically connected to magnetic poles located on the outside of the magnet, and form part of a magnetic circuit.

In the magnetron of the present invention having the structure described above, the magnet is held in such a way that it is suspended from the yoke fixed to the main body of the oscillator, so strong mechanical stress is not applied to the magnet itself, and the magnetron can be operated reliably. protected.

Also, since the magnet can be assembled without being in direct contact with the main body,
Heat associated with operation is not easily transferred to the magnet, and stable operation can be obtained even when the magnet has a relatively large temperature coefficient.

In particular, if a gap is provided between the magnet and the main body as in the above embodiment, heat conduction from the main body to the magnet can be further suppressed.

In this way, the present invention allows even relatively fragile magnets such as rare magnets to be used satisfactorily.

The permanent magnet used in the present invention has an outer diameter that is sufficiently smaller than the outer diameter of the main body of the oscillating unit, that is, the anode body thereof, so it is light in weight, and the means for holding the magnet in the yoke does not force the yoke to strongly hold it. It is not necessary to construct the magnet so that it is pulled.

In the magnetron of the embodiment shown in FIGS. 4 and 5, a cylindrical magnet 41 and a ring-shaped pole piece 45 joined to this magnet are fixed together to a yoke 39 with a holder 43.
It is placed close to the sealed body 36 with a slight gap 47 between them.

A cooling air guide device 52 is provided on a part of the cooling fins 51 attached to the outer periphery of the anode body 31 to divide the cooling air and guide it into the gap.

As a result, the cooling air passes through the air gap 47, the cathode stem 34, the outer surface of the magnet 41, and the wall surface of the central hole as indicated by the arrow 53.

In this way, the magnet and cathode stem 34 are efficiently cooled.

The yoke 39 is arranged diagonally so as not to obstruct the passage of cooling air, is attached so as to be in contact with the side surface of the positive body, and is mechanically fixed to the main body.

Cooling fins are fitted on the outside of them.

This magnetron also exhibits the same effects as those of the above-mentioned embodiments, and also effectively cools the magnet.

[Brief explanation of drawings]

Fig. 1 is a half sectional view showing the general structure, Fig. 2 is a longitudinal sectional view showing an embodiment of the present invention, Fig. 3 is a perspective view of the main part of the structure shown in Fig. FIG. 5 is a longitudinal sectional view of a main part showing another embodiment, and FIG. 5 is a top view of the one shown in FIG. 4. 30...Oscillating unit main body, 33...Cathode, 32
...Anode vane, 38...Electron action space, 41,42...Magnet, 39,40...
... Yoke, 43, 44... Holder (holding means).

Claims (1)

[Claims] 1. An oscillating unit main body having a cathode anode vane and a cylindrical anode body whose opposing spaces form an electron action space and whose interior is a vacuum region, and disposed coaxially with the main body above the main body outside the vacuum region. a permanent magnet that is mechanically held by the cylindrical anode body of the main body, surrounds the main body and the permanent magnet, and is magnetically connected to the outer magnetic pole of the permanent magnet to form a magnetic path. 1. A magnetron comprising a magnetic yoke, wherein the permanent magnet is held and fixed to the magnetic yoke by a holder so as to form a gap between the magnet and the main body.