JP2000274974A - Method for sealing end part of heat pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive improvement of production efficiency by omitting drawing work in sealing an end part for injecting and discharging working fluid into and from a heat pipe. SOLUTION: In the case that condensable working fluid is injected after noncondensable gas is exhausted from the inside and a metal pipe material 3 of which an outside diameter is approximately constant over all length is sealed, the pipe material 3 is located on an arcuate recess receiving surface 7. The pipe material 3 is crushed by a punch 9 radially from the state, and a crush part is formed in a shape being parallel with the recess receiving surface 7 and having close contact with each inside wall surface along a whole circumference at the crushed part. An edge part of the crushed part is melted and connected to integrate together the wall surfaces of the pipe material 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a heat pipe for transporting heat as latent heat of vaporization of a working fluid.
In particular, the present invention relates to a method for sealing an end of a container for injecting and discharging a working fluid.

[0002]

2. Description of the Related Art As is well known, a heat pipe is one in which a condensable fluid such as pure water or alcohol is sealed as a working fluid in a container such as a hermetically sealed metal pipe. Therefore, the end of the container needs to be completely sealed so as not to cause inflow of air and leakage of the working fluid. In particular, at the end of the working fluid injection / discharge side,
When the heating expelling method is adopted as the working fluid enclosing means, the sealing is performed while continuously discharging the working fluid vapor, so that a more airtight sealing method is required.

Therefore, in the prior art, as an example, a copper pipe material having one end sealed in advance is prepared, and the opening end of the pipe material is swaged (drawn) so as to be coaxial with the center axis of the pipe material. A small-diameter portion is formed on the upper portion, and the small-diameter portion is crushed in a radial direction by a punch and a die to form a flat crushed portion in which the inner wall surfaces are in close contact with each other. There is a sealing method that closes together. In this type of sealing method, the drawing process is performed by setting the outer diameter of the small diameter portion in advance so that the flat crushed portion does not protrude outward in the radial direction of the container.

That is, in a heat pipe having a structure in which the maximum width of the flat crushed portion is larger than the outer diameter of the container, the flat crushed portions are damaged by, for example, catching together in a state in which a large number of the flat crushed portions are housed. Not only might there be
This is because the substantial outer diameter of the container is increased, and accordingly, an occupied space is increased, which causes inconvenience. In other words, the above-mentioned conventional sealing method employs a means for reducing the diameter of a part of the container by performing drawing in order to prevent the flat crushed portion from protruding.

[0005]

As described above, in the above-mentioned conventional sealing method, not only the step of sealing the opened end of the pipe material but also the step of reducing the diameter of the pipe material is indispensable. One step is required in addition to the step and the welding step. Along with that, in the above conventional sealing method,
There was a disadvantage that production efficiency was poor.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for sealing an end of a heat pipe, which can improve production efficiency.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a method of exhausting a non-condensable gas from the inside, then injecting a condensable working fluid, and reducing the outer diameter to the entire length. In sealing a substantially constant metal pipe material over the entirety, the pipe material is arranged on an arc-shaped concave receiving surface, and the pipe material is crushed in a radial direction by a punch so as to follow the concave receiving surface. It is characterized in that a crushed portion is formed in such a shape that the inner wall surfaces are in close contact with each other over the entire circumference at the crushed portion, and the tip end portion of the crushed portion is fusion-bonded.

Therefore, according to the present invention, it is possible to form a crushed portion having a structure that does not protrude outward in the radial direction of the container by making the concave receiving surface have a structure corresponding to the outer diameter of the pipe material. It is possible. Therefore, it is possible to close the opening end of the pipe material without performing the drawing process, and therefore, the productivity is excellent.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIG.
This will be described with reference to FIG. First, a pipe material 3 made of copper or an alloy thereof, stainless steel, aluminum, an alloy thereof, or the like is prepared as a material of the container 2 of the heat pipe 1. More specifically, the pipe member 3 has a straight shape, and has a constant outer diameter and a constant thickness over its entire length. Further, one end of the pipe member 3 is sealed in advance by appropriate means, whereas the other end (opening end portion 4) of the pipe member 3 has a flat end surface, and The structure is orthogonal to the central axis of the material 3.

Then, a non-condensable gas such as air is exhausted from the inside through the opening side end 4 and a predetermined working fluid is injected into the pipe member 3 to form a heat pipe.
Next, a crushing process is performed on a portion of the pipe material 3 where a non-crushed portion 5 having a predetermined dimension is left from the opening side end portion 4 to form a crushed portion 6 whose inner wall surfaces are crimped. As shown in FIG. 1, the processing is performed by forming a die 8 having a concave receiving surface 7 on an opening end 4.
Is installed, and the punch 9 whose tip portion forms an arc surface is pressed against the pipe material 3 from the outside in the radial direction.

The concave receiving surface 7 of the die 8 is a straight groove having a U-shaped cross section having a depth of about the outer diameter of the pipe material 3 to be formed, and the bottom surface portion 10 having an arc shape. The curvature is set to be the same as the curvature of the outer peripheral surface of the pipe material 3. In addition, a pair of side surface portions 11 in the concave receiving surface 7
Both are flat surfaces and each has a vertical posture. The distance between the side portions 11 is set to be substantially the same as the outer diameter of the pipe material 3. That is, the die 8 has a structure in which the pipe member 3 can be moved in the radial direction from the opening on the upper surface thereof and can be disposed in close contact with the bottom surface 10 of the concave receiving surface 7.

On the other hand, the punch 9 is a prismatic block having a certain length in the depth direction in FIG. 1 and having flat surfaces whose left and right side surfaces are parallel to each other. The cross section in the left-right direction in FIG. 1 at the front end has an arc-shaped structure. The curvature of the arc surface is
The curvature is set larger than the curvature of the outer surface of the pipe material 3.
The left and right side surfaces in FIG. 2 at the tip of the punch 9 are each formed as an inclined surface 12, that is, tapered so that the lateral dimension decreases toward the lower side in FIG. Structure. Each inclined surface 12
Is set to be longer than the outer diameter of the pipe material 3.

As shown in FIG. 1, the punch 9 is configured so as to be vertically lowered and raised in a posture in which the center line in the width direction thereof coincides with the center line in the width direction of the die 8. The distance between the outer surface of the punch 9 and the outer surface of the concave receiving surface 7 at the lowest position is 2 mm of the wall thickness of the pipe material 3.
The setting is slightly narrower than twice.

Accordingly, a punch 9 is provided on the upper surface of the pipe member 3.
When the punch 9 is further pushed toward the die 8 from the state where the end portions of the pipes 3 are in contact with each other, as shown in FIG. The inner wall surface of the upper surface of the pipe member 3 comes into close contact with the inner wall surface of the lower surface portion and the inner wall surface of the side surface immediately before the tip of the punch 9 reaches the lowermost position, starting to be recessed toward the axis.
In this case, deformation near the outer diameter of the pipe 3 is restricted by contacting the vicinity of the boundary from the side surface to the upper surface of the pipe 3 with the side 11 of the concave receiving surface 7.

When the distance between the punch 9 and the die 8 is further reduced from the above state to the lowest position, the entire inner wall surface of the deformed portion on the upper surface of the pipe member 3 becomes the inner wall surface of the lower surface and the side surface. It is crimped to the whole, and this part becomes the crushed part 6. The crushing portion 6 has an inner surface that follows the shape of the tip of the punch 9 and an outer surface that follows the outer surface shape of the pipe member 3, and has a maximum width (a radial dimension of the pipe member 3).
Has a structure substantially equal to the outer diameter of the pipe material 3. In other words, the structure is such that the pipe member 3 does not protrude outward in the radial direction. As described above, the pipe member 3 is pressed and sealed at the crushed portion 6 at the opening end 4 thereof.

Next, the crushed pipe material 3 is welded. Specifically, the pipe material 3 is held in a posture in which the end provided with the crushed portion 6 is directed upward, and in this state, the non-crushed portion 5 remaining on the distal end side from the crushed portion 6 is heated and melted and joined. I do. As the means, for example, gas welding in which the base material is melted by a gas flame can be mentioned. In this case, since the non-crushed portion 5 has a substantially cylindrical shape, the molten metal generated by heating fills the hollow portion, and the molten metal above the hollow portion has a hemispherical shape above the crushed portion 6. Solidifies.

FIGS. 5 and 6 show the state after the crushing and welding are performed as described above. As shown here, the crimped portion remains as it is, and the molten metal Is solidified in the state of a plug, and the pipe material 3 is formed by both the crimped portion and the welded portion.
Are hermetically sealed. As a result, the heat pipe 1 has a structure in which the width of the crushed portion 6 is substantially equal to the outer diameter of the container 2.
Is completed.

Next, another embodiment of the present invention will be described with reference to FIGS. The example shown here is an example in which the non-crushing part 5 is not provided. The same members as those in the above specific example are denoted by the same reference numerals, and detailed description thereof will be omitted. A pipe material 3 having the same structure as that of the above specific example is prepared, and the opening side end 4 is crushed by a punch 9 and a die 8 and pressed. This die 8 and punch 9
The one having the same structure as the specific example shown in FIG. 1 is employed.

The pipe material 3 is provided inside the concave receiving surface 7 of the die 8.
The opening side end 4 is set. In that case, the distal end surface of the pipe material 3 is arranged so as to coincide with the boundary between the distal end portion of the punch 9 and the right inclined surface 12 in FIG. 2, and the punch 9 is lowered from that state, and The pipe material 3 is crushed from the outer surface side. As a result, a crushed portion 6 having a U-shaped cross section in which the inner wall surfaces are in close contact with each other is formed at the end of the pipe material 3. In other words, the joint surface between the inner wall surfaces of the crushed portion 6 has a structure in which the end surface of the pipe material 3 appears, that is, as shown in FIG. It has a structure in which one of the imitating walls is not provided.

Next, welding is performed along the joining portion of the tip end surface of the pipe material 3. As an example of the welding means, TIG (inert gas tungsten arc) welding is employed. As the TIG welding machine, a conventionally known TIG welding machine is employed. Although not particularly shown, a welding machine main body equipped with a control device, a welding power supply for supplying power to the welding machine body, and a flexible tube are used. It has a welding torch connected to the welding machine body. Further, the welding torch is configured to supply a shielding gas such as argon (Ar) to the outside from a gas nozzle provided at a tip portion thereof. Further, the welding torch is provided with a tungsten electrode ( (Both not shown) are provided.

Then, welding is performed on the pipe material 3 using the TIG welding machine having the above configuration. First, the pipe member 3 is held horizontally, or the pipe member 3 is held upright so that the end on the side of the crushing section 6 is on the lower side.
The tungsten electrode of the welding torch is arranged at a predetermined distance from the end face of the welding torch. Further, an arc is generated between the pipe member 3 and the tungsten electrode while a shield gas is supplied from the gas nozzle toward the end face of the crushed portion 6 in a state where the filler wire as the filler material is arranged between the two.

In this state, the welding torch is moved along the U-shaped joint surface. Then, a part of the filler wire and the pipe material 3 is melted, and a droplet adheres in a state of covering the joint surface, and the droplet is cooled naturally and solidified as it is. As a result, a weld bead is formed along the joint surface, and the pipe material 3 is hermetically sealed by the welded portion and the crushed portion 6 to form the heat pipe 1.

According to this specific example, it is possible to form the crushed portion 6 at the more distal end position by the amount that the non-crushed portion 5 is not provided at the end of the pipe material 3, so that the same pipe material 3 can be made of a material However, there is an advantage that the heat pipe 1 having a substantially longer overall length can be manufactured as compared with the specific example shown in FIG.

[0024]

As is apparent from the above description, according to the present invention, when sealing a pipe material serving as a heat pipe container, the pipe material is arranged on an arc-shaped concave receiving surface and a punch is provided. Is formed by crushing in the radial direction, forming a crushed portion having a shape along the concave receiving surface and closely contacting the inner wall surfaces over the entire circumference at the crushed portion, and then melting and joining the tip portion. Since it is possible to form a crushed portion having a structure that does not protrude outward in the radial direction of the pipe material, it is not necessary to perform a drawing step, and thus it is possible to improve productivity.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an arrangement relationship among a punch, a die, and a pipe material.

FIG. 2 is a schematic view showing the structure of a punch.

FIG. 3 is a schematic view showing a state where the punch is lowered into a concave receiving surface.

FIG. 4 is a schematic view showing a state in which the punch is raised from within the concave receiving surface.

FIG. 5 is a schematic view showing a completed heat pipe with a part cut away.

FIG. 6 is a sectional view taken along a center axis of the heat pipe having the structure shown in FIG.

FIG. 7 is a schematic diagram showing a partially completed structure heat pipe having no crushing portion, with a part cut away.

8 is a cross-sectional view of the heat pipe having the structure shown in FIG. 7, taken along a central axis.

9 is a schematic view showing an end face of a crushed portion in the heat pipe having the structure shown in FIG. 7;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Heat pipe, 3 ... Pipe material, 4 ... Open side end part, 6 ... Crushed part, 7 ... Concave receiving surface, 8 ... Dies, 9
... a punch.

Claims (1)

[Claims] 1. An arc-shaped concave receiving surface for sealing a metal pipe material into which a condensable working fluid is injected after exhausting a non-condensable gas from the inside and whose outer diameter is substantially constant over its entire length. While arranging the pipe material on the upper side, the pipe material is crushed in the radial direction by a punch, the shape is along the concave receiving surface, and the inner wall surfaces are in close contact with each other over the entire circumference at the crushed portion. A method for sealing an end of a heat pipe, wherein a crushed portion is formed, and a tip portion of the crushed portion is fusion-bonded.