JP2698106B2 - Manufacturing method of magnetron - Google Patents

Description

The present invention relates to a method for producing a magnetron.

(B) Conventional technology A method for manufacturing a general magnetron will be described with reference to FIG. First, a magnetron will be described. (1) is an oxygen-free copper cylindrical anode body, and a plurality of vanes (2) are integrally formed from the inner surface toward the center. (3) is a cathode disposed in a space surrounded by the tip of the vane, and has a filament (4). (5) and (6) are a pair of magnetic pole pieces mounted on both opening edges of the anode body (1), and (7) are air gaps on one opening edge of the anode body (1) via the sealing metal (8). The hermetically sealed cathode stem supports the cathode leads (9) (10) supporting the cathode (3). (11) is the anode body (1)
An oxygen-free copper exhaust pipe hermetically sealed to the other opening edge via a sealing metal (12) and an insulator (13). One end of the exhaust pipe (14) is connected to the vane (2) and the other end is exhausted. An antenna lead inserted into a pipe (11), and the exhaust pipe (11) is sealed at a predetermined position (15) together with an antenna lead (14) by a sealing cutting tool (1).
The sealing is cut off by 6), and the inside of the magnetron is kept in a vacuum.

The magnetron is composed of the above. The exhaust pipe (11) is connected to the coupling device of the vacuum device, that is, the exhaust pipe (11) is inserted into the suction pipe (17) of the vacuum device, and the tightening ring (18) is sucked. Tube (1
7) Tighten to the outer circumference of the cooling chamber (19) formed at the outer peripheral tip, and place O between the intake pipe (17) and the tightening ring (18).
The exhaust pipe (11) is hermetically attached by elastically deforming the ring (20).

Then, electricity is supplied to the filament (4), and the vacuum device is operated while the magnetron is heated to 400 to 600 ° C., which is higher than the temperature at the time of use, to evacuate the air inside the magnetron. That is, the magnetron is heated in order to improve the exhaust efficiency and promote the release of the gas adhering to the surface of each member constituting the magnetron.

Since the exhaust pipe (11) is made of oxygen-free copper, its thermal conductivity is high, and the heat of the magnetron is also transmitted to the coupling device of the vacuum device, but the O-ring (20) is generally made of synthetic rubber, Since the operating temperature is about 250 ° C, the O-ring (20)
May be damaged. Therefore, a water supply pipe (21) and a drain pipe (22) are connected to a cooling chamber (19) at the outer periphery of the tip of the intake pipe (17), and the O-ring (20) is cooled by passing cooling water through the cooling chamber (19). It has become.

However, when cooling water is passed through the cooling chamber (19), the exhaust pipe (11) is also cooled. Since the exhaust pipe (11) is made of oxygen-free copper with high thermal conductivity, the effect of this cooling is restricted. There is a drawback that the temperature rise is suppressed and the gas adsorbed on the surface cannot be completely discharged even to the deposition metal (12).

That is, the temperature distribution of the magnetron will be described with reference to FIG. 2. A, B, C, D, E and F are respectively a cathode-side sealing metal (8), an anode body (1) and an output-side sealing in FIG. Temperature measurement points at the end of the exhaust pipe (11), at the center of the exhaust pipe (11), and at the other end of the exhaust pipe (11). Is the temperature distribution. From FIG. 2, the temperature at the temperature measurement point D at one end of the exhaust pipe (11) is about 250 ° C.
It can be seen that the temperature is lower than about 300 ° C. in actual use. This temperature measurement point D is a part constituting the antenna after the sealing of the exhaust pipe (11) is cut off.
In the above-described evacuation process, the gas remaining adsorbed on the surface is released, so that the degree of vacuum of the magnetron is reduced and the normal oscillation operation is hindered.

(C) Problems to be Solved by the Invention The present invention has been made in view of the above-mentioned drawbacks, and is directed to a magnetron that can suppress the influence of cooling from the vacuum apparatus side and produce a high-quality magnetron free from a vacuum degree defect. It is an object to provide a manufacturing method.

(D) Means for Solving the Problems In order to solve the above problems, a magnetron exhaust pipe having a plurality of vanes and a cathode disposed in a space surrounded by the vane tips is made of a highly conductive material. A part composed of a low thermal conductive material and a part composed of a low thermal conductive material. A part composed of a high conductive material is connected to the anode body side, and a part composed of a low thermal conductive material is connected to a vacuum device. Then, the vacuum device is operated while the inside of the anode body is heated to discharge the gas in the anode body, and the highly conductive material portion of the exhaust pipe is sealed off together with the antenna lead.

(E) Action The low thermal conductive material portion of the exhaust pipe is airtightly mounted on a vacuum device by an O-ring, and air is exhausted into the inside while heating the magnetron, while the O-ring is cooled by cooling water. And prevent deterioration due to the influence of heat from the magnetron. The cooling water also cools the low thermal conductivity material portion, but the cooling water exerts less influence on the high conductivity material portion side. Therefore, each component of the magnetron becomes hot, and the gas adsorbed on the surface of each component is almost completely released.

(F) Embodiment One embodiment of the present invention will be described below in detail with reference to FIG.
Note that the same parts as those in the related art are denoted by the same reference numerals, and description thereof is omitted.

An exhaust pipe (23) is an oxygen-free copper metal pipe (2) having a sealing part (24a) air-tightly attached to an insulator (13) at one end.
4) and a connection pipe (25) made of a low heat conductive material such as iron or ceramic which is hermetically joined to the other end of the exhaust pipe by brazing or the like, and the metal pipe (24)
Is formed to have a length such that the other end extends outward from a predetermined position (15) where the sealing cut is performed.

Thus, the connection pipe (25) of the exhaust pipe (23) is hermetically attached to the coupling device of the vacuum device, and the filament (4) is energized in the same manner as in the prior art. Discharge the cooling room (19)
Protect the O-ring (20) by passing cooling water through it.

The connection pipe (25) is cooled by the cooling water, but since the connection pipe is made of a low heat conductive material,
The effect of cooling by the cooling water on the metal pipe (24) side is reduced. Therefore, the anode body (1), the pole pieces (5) (6),
Sealing metal (8) (12), cathode stem (17), insulator (1
3) and the temperature of the metal pipe (24) becomes high, and the gas adsorbed on the surface of each member is almost completely released.

When the inside of the magnetron reaches a predetermined degree of vacuum, a predetermined position (26) of the metal pipe (24) is crushed together with the antenna lead (14) with the sealing cutting tool (16) to perform sealing and cutting, and the magnetron is evacuated. To hold.

An example of a temperature distribution in which the connection pipe (25) is made of mild steel is shown by a solid line in FIG. From FIG. 2, it can be seen that this example has a higher overall temperature than the conventional one shown by the broken line.
Among the measurement points A, B, C, and D in the portion constituting the magnetron held in a vacuum, the temperature is about 470 ° C. at the lowest measurement point D, and the gas adsorbed on the surface of each component is almost completely. It can be seen that it is released. Therefore, no gas is released from the surface of each component during use, and the degree of vacuum inside the magnetron does not decrease.

(G) Effects of the Invention As described above, according to the present invention, the influence of cooling water cooling on magnetron components such as the anode body and the highly conductive material portion of the exhaust pipe during the exhaust process is reduced, and the magnetron configuration is reduced. Parts can be heated to a sufficiently high temperature,
The gas adsorbed on the surface of each component can be almost completely released, and therefore, there is an effect that the degree of vacuum failure can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view for explaining a magnetron manufacturing process according to an embodiment of the present invention, FIG. 2 is a temperature distribution diagram of the magnetron, and FIG.
FIG. 1 is a sectional view illustrating a conventional magnetron manufacturing process. (1) Anode body, (14) Antenna lead, (23)
... exhaust pipe, (24) ... metal pipe (highly conductive material part), (25) ... connecting pipe (low thermal conductive material part).

Claims (1)

(57) [Claims] 1. A magnetron exhaust pipe having a plurality of vanes and a cathode disposed in a space surrounded by vane tips, a portion made of a highly conductive material and a portion made of a low heat conductive material. The part made of a highly conductive material is connected to the anode body side, and the part made of a low heat conductive material is connected to a vacuum device, and the vacuum device is heated while heating the anode body. A method for manufacturing a magnetron, wherein the gas is discharged from the anode body by being activated, and the highly conductive material portion of the exhaust pipe is sealed off together with the antenna lead.