JPS5930778B2 - vacuum container - Google Patents

Description

[Detailed description of the invention] TECHNICAL FIELD The present invention relates to improvements in vacuum containers, particularly in envelopes.

A variety of materials are used for the envelopes of vacuum containers, but copper is used in some fields.

For example, pure copper has traditionally been used for transmitting tubes and magnetron envelopes.

However, with the recent miniaturization of devices, there is a desire to reduce the thickness of the members constituting the envelope as much as possible.

Furthermore, the material constituting this type of vacuum container must be sufficiently resistant to atmospheric pressure and must not undergo thermal deformation.

The present invention is aimed at satisfying the above-mentioned needs, and is intended to provide at least a portion of the envelope, that is, a portion that is required to be thinner, or a portion that is required to have strength and the ability to withstand thermal deformation. It is formed from a precipitation type copper alloy.

That is, the present invention uses chromium and zirconium alone or in combination in an amount of 0.3 to 2% by weight, and at least one selected from the group consisting of magnesium silicon, germanium, and boron.
．． This is a vacuum vessel in which at least a portion of the envelope is formed of a precipitated copper alloy of 0.005 to 0.1 and the remainder substantially made of copper.

Chromium and zirconium contribute to improved strength and heat resistance, but degrade electrical and thermal conductivity.

Therefore, the above numerical values are set based on the balance of these characteristics.

Silicon, magnesium, germanium, and boron improve strength and heat resistance when added in small amounts; however, when added in large amounts, thermal conductivity deteriorates, so the above values were set.

Preferably it is 0.01 to 0.05%. The precipitation type copper alloy of the present invention is produced by melting an alloy having the above-mentioned composition structure, and then
It is obtained by heating to 1000°C, preferably 930 to 980°C, solution treatment, and then cold working.

The desired plate is subjected to the usual hot processing before solution treatment,
It is permissible to process the material into various shapes such as rods.

In this case, the hot working temperature is preferably 700 to 800°C.

If solution treatment is performed at too high a temperature, precipitates will collect at grain boundaries and crystal grains will become coarse.

These phenomena must be avoided because they cause roughness during processing and cracking during bending.

If the solution treatment temperature is low, ductility may be insufficient or cracks may occur during press working.

Further, in cold working, it is desirable that the working rate is 60 or more.

Four examples of the precipitation type copper alloys used in the present invention and their characteristic values are shown in Table 1 below.

A magnetron envelope will be described below as an example of a vacuum vessel.

Recently, as magnetrons have become popular for use in microwave ovens, efforts have been made to make them more compact.

The practical use of rare earth magnets as permanent magnet materials has significantly contributed to the miniaturization of magnetrons.

The special feature of this magnet is that it can be installed very close to the electron working space of the magnetron.

On the other hand, however, as the magnetic force decreases significantly as the temperature rises, the actual situation is that this magnet must be placed outside the members constituting the vacuum envelope of the magnetron, that is, outside the vacuum region.

This contradicts the above-mentioned arrangement of the magnet as close to the electron action space as possible.

In order to solve this problem, it is necessary to reduce the thickness of the members constituting the vacuum envelope as much as possible.

However, the material constituting the vacuum envelope must be able to withstand atmospheric pressure sufficiently and not undergo thermal deformation, and hitherto it has not always been possible to obtain a material suitable for this purpose.

The magnetron of the embodiment shown in FIGS. 1 to 5 has the following structure.

Cylindrical rare earth permanent magnets 12, 13 are arranged on both upper and lower sides of the oscillating unit main body 11, and a cross-blowing radiator 14 is fixed to the outer periphery of the main body L1, and cooling air flows from the direction of the arrow 15. It looks like this.

A shield box 16 is fixed to one end of the main body 11, and a cathode input terminal 17 is provided.

This shield box 16 is made of a magnetic material, and an open bent cylindrical portion 18 at the center of the bottom is fitted into the root portion of the radiator 14.

The outer magnetic pole S of one magnet 12 is magnetically coupled to the shield box 16 via a cylindrical magnetic body 23.

Further, a magnetic yoke plate 19 is disposed so as to surround the outside of the radiator 14, and a portion thereof is extended laterally to form a magnetron mounting bracket 20, 20, . . .

The outer magnetic pole N of the other magnet 13 is coupled to the bottom of the yoke plate 19 via a disc-shaped magnetic body 24 .

A gasket 22 made of a fine metal wire mesh is fitted to the base of the output antenna section 21, which forms a part of the main body U, and is connected to a high frequency coupler (not shown).

An insulating plate 2 is installed inside the upper opening of the shield box 16.
A conductive lid 26 with a number 5 is fitted, and a number of ventilation holes 27 are bored in the side wall.

Cathode connection terminals 29 and 30 provided on the cathode stem 28 forming a part of the main body L1 are connected to the cathode input terminal 17 via a choke coil (not shown) and a feedthrough capacitor 31.

The main body of the oscillating unit is made up of a plurality of anode vanes 52 arranged and fixed radially inside a cylindrical anode body 51.

These constitute a resonant cavity. An electron emitting cathode 53 is arranged on the tube axis, and a cylindrical electron action space 54 is formed between the cathode 53 and the anode vane 52.

Near the inner ends of the anode vanes, upper and lower pairs of strap rings (equalizing rings) 55, 56, and 57, 5B are fixed to short-circuit every other anode vane.

This strap ring is made of a magnetic material such as iron, its surface is plated with copper or silver to improve electrical conductivity, and it is brazed in contact with a copper anode vane at a predetermined position.

Now, sealing metal bodies 61 and 62 are respectively sealed to the open ends of the cylindrical anode body 51 so as to airtightly close these ends.

On the side of the cathode stem 28 extending outward along the tube axis, a thin sealing metal body 61 is drawn into a substantially cup shape, and an annular magnetic pole piece 63 such as iron is provided at the center of the bottom.
is hermetically soldered.

Further, an exhaust pipe 64 is fixed at a location offset from the central axis.

The outer peripheral portion 61a extends while contacting the inner peripheral wall of the anode body 51, and is further bent outward along the edge of the anode body.

The outer periphery of the end of the anode body is scraped to form a step, and the tip 51a has a thickness approximately equal to that of the sealed metal body 61, and the entire circumference of the joint between the two is in an inert gas atmosphere. Arc welding is performed inside to create an airtight seal.

This welded portion is designated by the reference numeral 65. A metal cylinder 66 constituting a part of the cathode stem 28 is fixed to the central opening of the pole piece 63, and an insulating tube 67 made of ceramic, a terminal plate 68, an insulator 69, and a terminal plate 70 are fixed in this order. .

A center support rod 71 and a support cylinder 72 that support the cathode 53 pass through the pole piece 63.

A dielectric spacer 73 is interposed between the support rod 71 and the support tube 72 in order to maintain a coaxial positional relationship between the two and to prevent transmission of unnecessary microwaves.

Now, on the outside of the iron pole piece 63, a permanent magnet 12, which is a combination of two pieces, is arranged so as to surround the metal cylinder 66.

This magnet 12 is bound by a ring 76 made of a non-magnetic material such as aluminum, and the stepped portion 6 of the sealing metal body 61
It is fitted inside 1b and is mechanically held.

As described above, the magnetic body 23 is in contact with the outer magnetic pole S of the permanent magnet, and the outer peripheral edge of this negative body 23 is brought into contact with the bottom of the shield box 16, and is fixed by the cut and raised piece 16a.

At the other end of the anode body 51 on the side of the output antenna part, a sealing full body 62 is formed with a recessed central part, and is hermetically sealed.

An output antenna portion 21 is provided in a protruding manner at a location away from the central axis of the sealed metal body 62, and an output antenna rod 86 having one end connected to one of the anode vanes passes through it.

Further, inside the central recess 62a of the sealing metal body 62, there is an iron ring-shaped pole piece 88 having an inclined surface 87, and a flat disc-shaped iron auxiliary pole piece 8 fitted inside the pole piece 88.
9 is inserted, and a cylindrical permanent magnet 13 is further inserted.

The pole piece 88 and the auxiliary pole piece 89 form a substantially disc-shaped pole piece 81 joined to the inner magnetic pole of the cylindrical magnet 13.

Now, the cylindrical anode body 51 is formed of copper or an alloy containing copper as a main component, and the sealing metal body 6L62 that is hermetically sealed thereto contains chromium and zirconium alone or in a combination of 0.3~ It is formed of a precipitated copper alloy consisting of 0.005 to 0.1 weight of at least one selected from the group consisting of 2 weight weight hereditary silicon, magnesium, germanium, and boron, and the remainder being substantially copper. Ru.

The inventor has developed an oscillation frequency of 2450MHz and an output power of 800W.
To give an example implemented in a magnetron, the anode body is made of copper, its diameter (outer diameter) is 40 mm, and its wall thickness is 40 mm.
On the other hand, the sealing metal body was made of a precipitated copper alloy consisting of 0.65% chromium, 0.4% zirconium, 0.03% silicon, and the balance copper and had a thickness of 0.7 mvt.

Since the magnetron with the above structure is made of a special precipitated copper alloy as a sealed metal body, it has much higher mechanical strength than pure copper, and even if the wall thickness is made very thin, it can be used in a vacuum. It can be put to practical use as a member constituting a part of an envelope.

This made it possible to place the magnet outside the vacuum envelope as close as possible to the electron action space.

Of course, even if it is made thin, it will not be dented by atmospheric pressure, maintains its properties as a non-magnetic material, and can be perfectly arc welded to the anode body.

Furthermore, the thermal conductivity is sufficient for practical use, so the heat generated by the cathode etc. is effectively conducted to the anode body.
It is possible to suppress the temperature rise of the magnet.

In the magnetron of this embodiment, the magnetic circuit is constructed as schematically shown in FIG.

Note that the magnetic circuit portion composed of a magnetic yoke plate and the like is omitted in the figure.

Both the upper and lower magnets 12 and 13 are cylindrical rare earth magnets of the same shape and size, and the pole piece 63 connected to the magnet 12 on the cathode stem side has a perforated ring shape with a flat surface facing the working space. I am doing it.

On the other hand, the pole piece 81 connected to the magnet 13 on the output antenna side is a ring-shaped pole piece 8 having an inclined surface 87.
8 and an auxiliary pole piece 89 fitted inside thereof, the pole piece is a plate-like pole piece without holes, with the surface facing the working space substantially forming a concave shape.

And magnetic stop rings 55, 56, 57゜58
In combination with this, a uniformly distributed magnetic field is obtained in the working space 54.

In this case, on the cathode stem side, the diameter d2 of the center hole of the pole piece 63 is larger than the diameter d1 of the center hole of the magnet 12.
are formed with small dimensions, which also contributes to uniformity of the magnetic field distribution in the working space.

In the embodiment shown in FIG. 6, the pole piece 6 on the cathode stem side
This was done in order to solve the problem that the temperature of the magnet 12 tends to rise because the heat conductivity of magnet 3 is not very good.

That is, a copper or copper alloy plate 92 similar to the sealing metal bodies 61 and 62 of the previous embodiment is placed on the inside of an iron pole piece 63 with a thin stainless steel spacer 91 having poor thermal conductivity interposed therebetween. be.

This plate 92 is arranged so as to surround the pole piece 63, and is brazed to the sealing metal body 61 at a position extending further outward from the position corresponding to the magnet 12, that is, at a position 93.

As a result, the heat generated near the cathode is quickly transmitted to the sealing metal body 61 by the plate 92, and further radiated to the radiator via the anode body 51.

Temperature increases in the pole pieces and magnets are therefore avoided.

This also exhibits substantially the same function as that provided by extending the sealing metal body to the inside of the pole piece.

Although the present invention has been described above using the magnetron envelope as an example, the present invention is not limited to this.

[Brief explanation of the drawing]

Fig. 1 is a half-sectional view showing one embodiment of the present invention, Fig. 2 is a side view thereof, Fig. 3 is an enlarged longitudinal sectional view of the main part, Fig. 4 is a perspective view showing the magnet, and Fig. 5 is its side view. FIG. 6 is a longitudinal sectional view schematically showing a magnet circuit, and FIG. 6 is a longitudinal sectional view of a main part showing another embodiment of the present invention. 51... Cylindrical anode body, 52... Anode vane, 54... Electron action space, 6L62...
...Sealed metal body, 12,13...Permanent magnet.

Claims (1)

[Claims] 1 Chromium and zirconium alone or in combination from 0.3 to
2 weight ratio and at least one selected from the group consisting of silicon, magnesium, germanium, and boron at 0.00
A vacuum vessel in which at least a portion of an envelope is formed of a precipitated copper alloy having a thickness of 5 to 0.1 and the remainder being substantially copper.