JPS5989997A - Heat pipe and manufacture thereof - Google Patents

Abstract

PURPOSE:To make the external appearance of the heat pipe excellent and to improve its reliability by a method wherein an aluminum alloy pipe whose outer periphery is covered with a metal other than aluminum is used as a tip pipe such that an operating liquid is sealed into the pipe and after the metal covered section is welded by a resistance welding method, while the tip pipe is cut in a sealed condition. CONSTITUTION:The heat pipe consists of an aluminum alloy vessel 1 applied with a wick in the axial direction, an aluminum alloy cap 2, the tip pipe 3 and a stainless sleeve 4. Further, the tip pipe 3 is attached with a valve 5 and is fixed to an operating liquid sealing device 7 through a pipe 6. The operating liquid is sealed into the tip pipe 3 after a predetermined degree of vacuum is obtained by opening the valve 5 and then the valve 5 is closed. After that, the sleeve fitted about the tip pipe 3 is pressed by a press and welded airtight to the pipe by a resistance-welding method and finally, the resistance-welded section is cut at a position inbetween the center of that section and the valve 5 so that is cut in a favorable sealed condition without spoiling the airtightness of the tip pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat pipe and a method for manufacturing the same. A heat pipe is usually composed of a main body container having a wick and a tip tube. The inside of the main body container is evacuated from the tip tube. After filling the fluid, the chip tube is sealed off. The main container is made of metals such as copper, stainless steel, and aluminum alloys, as well as non-metals.

The tip tube is made of metal that is easy to seal.

Further, as the working fluid, one of water, methanol, chlorofluorocarbon, ammonia, etc., which is compatible with the material of the main body container, is used.

The heat pipe composed of the main body container and the chip tube must be airtight, and even when the chip tube is sealed off, the inside and outside must be completely airtight after being sealed off.

Conventionally, in this "sealing" process, if the chip tube was made of a metal that could be made airtight by crimping, such as copper, the end would be soldered or brazed after the chip tube was sealed by crimping. In the case of metals such as stainless steel that cannot be kept airtight by pressing, the method used was to use plastic processing to narrow down the sealing part or make them fit flat, then join them using fusion welding or resistance welding, and then cut them. .

However, when the tip tube is made of aluminum or aluminum alloy, the same method as for stainless steel is generally used. However, fusion welding is prone to internal design defects at the joint (strict control of welding conditions is required to achieve a highly airtight seal.Also, resistance welding also tends to cause defects such as dust and burns). Defects were likely to occur, and it was difficult to seal it with high airtightness.

Also, a method has been proposed in which other metals that are easy to seal, such as copper or stainless steel, are joined to the main body container or chip tube made of aluminum or aluminum alloy by friction welding, and the other metal parts are sealed. When aluminum or aluminum alloy is used for the main body, ammonia is often used as the working fluid due to its compatibility.7 The vapor pressure of ammonia is 10 atm at 25°C and 50"C.
The problem is that the reliability of joining aluminum or aluminum alloy with other metals becomes a problem because the pressure is as high as 19 atmospheres. It becomes a heat pipe.

The purpose of this invention is to provide a more reliable and economical commercial chip tube and a method for sealing the same.

Hereinafter, one example of this invention will be explained with reference to figures.

In Fig. 1, (1) is a main container made of aluminum alloy with a groove wick machined in the axial direction, (2) is a cap made of aluminum alloy, (3) is a tip tube made of aluminum alloy, and (4) is a cap made of aluminum alloy. ) is a sleeve made of stainless steel. (11 to (31) are hermetically sealed in advance by fusion welding, and fitted with the tip tube (3) until the sleeve (4) is sealed with an appropriate fit.

In the 11-piece heat pipe described above, the pulp (5) is attached to the chip tube (3) as shown in Figure 2, and the pulp (5) is taken to the working fluid enclosure device (7) through the piping (61) and 4 = J. The heat pipe connected to the working fluid enclosing device (7) first fully opens the pulp (5), then vacuums the inside of the heat pipe to obtain the required degree of vacuum, then seals in the working fluid and seals the pulp (5). Close the heat pipe containing the working fluid and insert the chip tube (3) with the pulp (5) closed.
Shape the sleeve mating part using a press so that the inner wall of the tip tube is in close contact and flat. After that, as shown in Figure 3, the tip tube (31) formed by resistance welding is airtightly joined.Then, the joined tip tube is attached to the pulp (5
) side allows for good sealing without compromising airtightness.

FIG. 4 shows the sealed portion after cutting is completed.

Next, a more specific example of sealing off a tip tube made of an aluminum alloy will be described.

The tip tube (31 is an aluminum tip tube with an outer diameter of 6M and a wall thickness of 1 mm) (31 is airtightly joined to the main body container (1) made of aluminum alloy 6063 with a groove wick formed in the axial direction by arc welding. The sleeve (4) was fitted with metal at the position where all the cutting operations in step 3) were to be performed.

The chip tube (3) is sealed off via the pulp (5).
After evacuating the inside of the heat pipe to a vacuum of 0-5 TOrr or more, the required amount of liquid ammonia is filled.

At the same time as filling is finished, close the pulp (5) and pulp (5)
and the pipe (6). The portion covered by the sleeve (4) is pressed using a hydraulic press until the inner surface of the tip tube is bonded to Wj.

At this time, the width of the flat part is about 10 mm, and the length is about 15 mm.
degree. Using a condenser type resistance welder, we applied a diameter of 11 mm to the center of this flat part, applied it completely, applied a force of 590 kg, and applied a charging voltage of 330 V.

Performed resistance welding. Then, the sealing process was completed by cutting on the pulp (5) side from the center of the resistance welding area.

As a result, in the helium leak test, leakage II
Xl 0 8 std@atm, cc/sec 300
There was no problem in the pressure test of 3 minutes of atmospheric pressure, and after this, the leak i: IX10lX1 was found in the helium leak test.
It was possible to obtain an airtight joint of 0-8 etd-at/BθC or less.

In the embodiment mentioned above, the sleeve is made of stainless steel ε+.
Although an example using US304 has been described, other stainless steels may also be used. It is not limited to stainless steel, but may also be made of other metals. Further, instead of the sleeve, it may be coated with metal such as chip metal by plating or thermal spraying.

As explained above, the present invention is a tip tube made of aluminum or an aluminum alloy coated with another metal, flattened tightly, and resistance welded.

Utilizing the effect of suppressing rapid heat generation by coated metal,
A uniform and strong gas-liquid bond with few defects can be obtained, and at the same time, the appearance and reliability are the same as above.

Also, the sealing part is pressed down by the metal to be welded.

A sealed cut portion that can withstand the internal pressure of the cylinder is obtained compared to a sealed cut made only of aluminum alloy. Furthermore, it can be applied to high-strength aluminum alloys that cannot be made using fusion welding or friction welding.

It has various advantages, such as being suitable for mass production if it is carried out consecutively with pressing, resistance welding, and pressing and resistance welding, which can be completed in a relatively short time.

[Brief explanation of drawings]

Figure 1 is a sectional view showing the drawing of the heat pipe, Figure 2 is a schematic diagram showing the piping connection of the heat pipe, Figure 3 is an enlarged sectional view of the sealing part during resistance welding, and Figure 4 is the completed sealing. It is an enlarged view of the later sealing part. In the figure, (II is the main container, (2) is the cap, (3
) is a chip tube, (4) is a sleeve, (5) is a pulp, (
6) is piping. (7) is a working fluid four-person device, (8) is an electrode, and (9) is a resistance welding part. In the figure, corresponding parts are indicated by the same reference numerals. Agent Makoto Kuzuno - Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) A heat pipe characterized in that a tip tube is a vibrator made of aluminum or an aluminum alloy whose outer periphery is coated with another metal, a working fluid is sealed in the tip tube, and the coating is sealed. . (2) Made of aluminum or aluminum alloy 1
The outer periphery of the vibrator is coated with another metal and used as a tip tube, and after the working fluid is fully enclosed in the tube, the aluminum or aluminum alloy coated with another metal is made to adhere flatly by plastic working. A method for manufacturing a heat pipe, characterized in that the deformed part is sealed by joining by resistance welding.