JPH10290091A - Working method for sealing part in heat pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to reinforce a softened part by a method wherein one end of a heat pipe comprising a group wick is pressure-welded and worked in a wave shape perpendicularly to its axial direction so as to be welded and sealed up and its pressure-welded and worked part is deformed by performing a pressure-welding and working operation or the like again. SOLUTION: A drawing and working operation in the direction of arrows is executed to one end of a heat pipe body 10, a pressure-welded part 16 is formed to be a cylindrical shape or a flat board shape, the side at the tip part f the pressure-welded part 16 is made hollow so as to become an injection part 12 for a working liquid, and a group wick is formed on its inner wall. Then, a stress is applied to the up-and-down direction of the pressure-welded part 16, the pressure-welded part 16 is pressure-welded and worked to be a wave shape or a step shape, and the injection part 12 is welded and sealed up by a welding material 14. In addition, the pressure-welded part 16 is pressure- welded and worked again so as to deform its shape. Thereby, a softened part can be restored to a resistant amount which is equal to, or more than, that in a part which is not welded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pipe provided as a part of a cooling device for electronic equipment and the like, and more particularly to a method for processing a sealing portion for hermetically sealing the inside.

[0002]

2. Description of the Related Art In personal computers and small portable electronic devices,
Heat generation of electronic components has become a problem, and various heat radiating devices have been proposed and provided. Above all, it is known that a heat radiating device including a micro heat pipe can obtain a more efficient heat radiating action than a heat radiating device having only a heat sink. In this heat pipe, hydraulic fluid is injected into the internal space,
The heat transfer effect is obtained by completely sealing this inlet.

[0003] The complete sealing of the inlet is performed as follows. FIG. 5 shows a conventional method of processing a heat pipe hermetically sealed portion. In FIG. 5, the heat pipe includes a main body 10 serving as a container and an inlet 12 for injecting a working fluid (not shown). The heat pipe is made of a material having good thermal conductivity such as copper or aluminum in a cylindrical or flat shape, and has a hollow inside and a group wick 20 provided on the inner wall as shown in FIG.

The group wick 20 has a structure in which a large number of fine grooves are provided on the inner wall of the main body for circulation of the hydraulic fluid, and is processed so as to sufficiently function the capillary phenomenon of the hydraulic fluid. Therefore, the corner of the groove is formed as sharp as possible. The above group wick 20
For a heat pipe having a diameter of about 4 mm, a depth (height) of about 0.15 mm and a width of about 0.2 mm are generally used.

A method of processing the above heat pipe will be described. A working fluid is injected from a working fluid inlet 12 provided at one end of a cylindrical heat pipe main body 10, and thereafter, electron beam welding, argon welding, silver brazing, or the like is performed. The injection port is sealed by the welding material 14 of FIG.

[0006]

However, the following problems occur in the heat pipe configured as described above. First, the "softening" effect of the material forming the heat pipe occurs due to the "smoothing" effect due to the high temperature of each welding and brazing operation performed when sealing the injection port 12, and this "softening"
It reduces the strength of the tubing forming 10 and has a significant effect on the durability of the heat pipe.

That is, as shown in FIG. 6, heat shock, which is a thermal shock during actual use, is repeated, so that volume expansion pressure due to vaporization of the working fluid and liquid freezing at a low temperature are repeated, and stress is applied. As a result, the above-described injection port 12 portion, that is, the softened portion gradually expands. When this operation is repeated, the softened portion is ruptured, and the sealing is not maintained, so that the hydraulic fluid leaks, of course, the heat transfer effect as a heat pipe is not obtained, and the heat radiation effect is not obtained. Causes malfunction.

In addition to the method of simply sealing the injection port 12 with the welding material 14, there is a method of crushing and closing the injection port 12. This is performed by crushing the vicinity of the inlet 12 in the axial direction. At this time, since the inside of the heat pipe has a wick structure, it is not easily crushed. For this reason, the wick passage can be blocked by pressing the heat pipe in a wave shape or a step shape in the axial direction of the heat pipe. Is inferior in reliability, so that the press-contact portion near the inlet 12 is inevitably long.
In general, sufficient sealing can be obtained even if the press-contact portion becomes long, and the performance as a heat pipe is maintained. However, as described above, the problem of heat shock due to softening at the time of welding occurs.

In view of the above problems, an object of the present invention is to provide a heat pipe in which a softened portion is reinforced and excellent effects can be obtained in any environment.

[0010]

In order to solve the above-mentioned problems, according to the present invention, after one end of a heat pipe having a group wick is pressure-welded in a wavy or stepwise shape perpendicular to the axial direction and welded and sealed. A method for processing a sealed portion of a heat pipe, wherein the pressed portion is deformed by re-pressing or the like or deformed by folding back.

[0011]

FIG. 1 shows a heat pipe according to a first embodiment of the present invention. FIG. 1 shows a cylindrical heat pipe, which is arranged in the order of processing steps. In FIG. 1, a shows a front view and a side view of the main body 10 of the heat pipe in an initial state.

FIG. 2B shows a front view and a side view of the main body 10 of FIG. 1A after one end is drawn in the direction of the arrow. In this b, the tip of the press-contact portion 16 to be subjected to the drawing process is the working fluid inlet 12 (not shown).

The heat pipe is made of a material having good thermal conductivity such as copper or aluminum in a cylindrical or flat shape, and has a hollow inside and a group wick 20 provided on the inner wall as shown in FIG. The group wick 20 has a structure in which a large number of microgrooves are provided on the inner wall of the main body for circulation of the hydraulic fluid, and is processed so as to sufficiently function the capillary phenomenon of the hydraulic fluid. The corners of the grooves are formed as sharp as possible.

C is an enlarged view of the portion A of b,
The figure after stress is applied to the press contact portion 16 shown in FIG. Here, c1 shows a side view, and c2 shows a top view of c1. In the present embodiment, the groove of the group wick is completely closed because the press contact portion 16 is stepped as shown by c1.

In FIG. 1D, the injection port 12 shown in FIG. 1C is welded or brazed, and the injection port 12 is sealed with a welding material 14. This welding is typically performed by electron beam welding, argon welding, silver brazing, or the like.

Thereafter, the press contact portion 16 is again subjected to press contact processing to finally form the press contact portion 16 as shown by e. In the first embodiment, the re-welding process
The cross-sectional shape of the press contact portion 16 is a curved surface as shown by e2 in FIG.

Next, a second embodiment is shown in FIG. In FIG. 2, the following points are different from those described in FIG. First, at c1, the press contact portion 16 is step-shaped, but in this embodiment, it is wave-shaped. 2
First, the shape at the time of the re-welding process has been changed from a curved surface shape into an S-shape as a front sectional view. Except for the above-mentioned parts, the description is omitted because it is the same as or equivalent to the first embodiment. In each of the above embodiments,
The first-stage pressure welding shown in c1 has the same effect regardless of whether it is stepped or wavy, and may be interchanged with each other. It is something.

FIG. 3 shows a third embodiment. In this embodiment, the same effect as in the first embodiment is obtained by folding the vicinity of the tip of the injection port 12 in place of the re-welding process. The other configuration is the same as or equivalent to that of the first embodiment, and a description thereof will be omitted. In the third embodiment, if the durability of the tube material is allowed, the re-welding process may be performed and then the turning process may be performed as in the first embodiment.

FIG. 4 shows a fourth embodiment. In FIG. 4, the re-welding process in the first embodiment is performed again in a wave-like manner, and the other parts are the same as or equivalent to those of the first embodiment, and therefore description thereof is omitted.

In the above embodiment, as shown in FIG. 1B, the vicinity of the injection port 12 is used as the pressure contact portion 16. However, depending on the diameter of the tube of the main body 10, this portion is not drawn and the main body 10 is not drawn. The same effect can be obtained even if the above-mentioned respective sealing processes are performed as a heat pipe having the same dimensions as above.

[0021]

According to the above configuration, the following effects can be obtained. First, by pressing, re-pressing, and turning back,
The crystal of the material of the main body 10 is deformed and fractured to form an altered layer, the work hardening of the material proceeds, and the softened portion is restored to the same or higher withstandability as the unwelded portion.

Further, even if the press-contact portion 16 expands beyond the outer shape of the heat pipe due to expansion of dimensions due to press-welding or softening during welding, it can be easily accommodated within the outer diameter of the main body 10 by the re-press-welding process. In addition, it can be easily attached to and inserted into a radiator such as a radiation fin. further,
The effect that the end of the heat pipe does not always need to be drawn can be obtained.

[Brief description of the drawings]

FIG. 1 shows a manufacturing process of a heat pipe according to a first embodiment of the present invention.

FIG. 2 shows a part of a manufacturing process of a heat pipe according to a second embodiment of the present invention.

FIG. 3 shows a part of a manufacturing process of a heat pipe according to a third embodiment of the present invention.

FIG. 4 shows a part of a manufacturing process of a heat pipe according to a fourth embodiment of the present invention.

FIG. 5 shows a conventional heat pipe.

FIG. 6 shows a conventional heat pipe in which a pressure contact portion is expanded.

FIG. 7 shows a sectional view of a heat pipe.

[Explanation of symbols]

 In the drawings, the same reference numerals indicate the same or corresponding parts. DESCRIPTION OF SYMBOLS 10 Main body 12 Inlet 14 Welding material 16 Press-contact part 20 Wick

Claims (5)

[Claims] 1. A heat pipe having a working fluid inlet at one end and having a wick therein, the vicinity of the working fluid inlet of the heat pipe is crushed by press working, and the inlet is welded. A method of processing a sealed portion of a heat pipe, wherein the pressed portion is deformed again. 2. A heat pipe having a working fluid inlet at one end and having a wick therein, the vicinity of the working fluid inlet of the heat pipe is crushed by press working, and the inlet is welded. A method for processing a sealed portion of a heat pipe, wherein the press-processed portion is turned back. 3. The method for processing a sealed portion of a heat pipe according to claim 1, wherein the pressing is performed by crushing in a wavy shape perpendicular to the axial direction. 4. The method for processing a sealed portion of a heat pipe according to claim 1, wherein the pressing process is performed by crushing in a wave shape perpendicular to the axial direction. 5. A heat pipe having a working fluid inlet at one end and a wick therein, the vicinity of the working fluid inlet is drawn, and the vicinity of the working fluid inlet of the heat pipe is pressed in a wavy or stepped manner. Processing, welding the relevant inlet,
A method of processing a sealed portion of a heat pipe, wherein the pressed portion is deformed or turned again.