JPH11201672A - Manufacture of heat pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing heat pipes with excellent performance efficiently. SOLUTION: The end of a pipe body 20 is crushed by a male die 10 and a female die 11, and it is turned through 90 degrees and is crushed by a male die 12 and a female die 13. Further it is turned through 90 degrees and is crushed by a male die 14 and a female die 15, and then it is sealed temporarily and the end thereof is welded and sealed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a heat pipe.

[0002]

2. Description of the Related Art A typical heat pipe has a structure in which both ends of a pipe body are sealed, and a proper amount of a working fluid (working fluid) is contained in a closed cavity.
In the heat pipe, heat is mainly transferred by the phase change and movement of the working fluid. Usually, copper, aluminum, stainless steel, or the like is often used as the material of the heat pipe container.

[0003] As a working fluid contained in the heat pipe, water, alcohol, an organic solvent or the like is used. As described above, since the heat pipe transfers heat by the phase change of the working fluid, in the case of a normal heat pipe, unnecessary gas such as air is removed from the sealed space as much as possible. In addition, mixing of oil and the like should be avoided as much as possible.

[0004] Therefore, in the production of the heat pipe, it is necessary to previously clean the inside of the heat pipe container appropriately to remove unnecessary oil components and the like and to remove unnecessary gas in the container. As a method of removing unnecessary gas, for example,
A method of degassing the inside of the container before injecting the working fluid, or injecting the working fluid from one end of a heat pipe container with one end sealed and then boiling the working fluid to eliminate the need to remain in the container A method is known in which a container is sealed while discharging a gas.

[0005]

In manufacturing a heat pipe, first, a pipe to be a container is prepared, and one end of the pipe is sealed by welding or the like. Next, after cleaning the inside, working fluid is injected from the other unsealed end, and then the unsealed end is sealed to obtain a predetermined heat pipe. Conventionally, as the method of sealing the other end, a method of directly sealing by ultrasonic welding or a method of temporarily sealing by temporarily pressing and then sealing by welding or the like. The method was known.

[0006] In ultrasonic welding, it is difficult to position the ultrasonic head used for the ultrasonic welding with the welded portion, and the consumable ultrasonic head is expensive, which is not desirable in terms of manufacturing cost. A method of temporarily sealing by temporarily pressing and then sealing by welding or the like is effective, but the shape of the sealing portion may be greatly expanded due to the pressing. In recent years, heat pipes are often used for relatively compact electric devices such as personal computers, and the external dimensions of the heat pipes have become strict due to the high mounting density inside these devices. For this reason, there is a case where it is necessary to perform an operation such as rounding a flat pressed portion to form a circular shape, and there is a problem in terms of manufacturing cost.

[0007] Therefore, it is conceivable to reduce the diameter of the portion to be pressed before the pressing and make it thinner, and then press the contact. However, there is a problem that the effective length of the heat pipe to be manufactured is shortened, and the number of work steps is increased, so that the manufacturing cost is increased. Further, if the pressure contact is performed in a form that is simply crushed into a flat plate shape, stress concentration occurs at the bent portion, and the strength of the sealing portion may decrease. In such a case, the pressure resistance and airtightness of the manufactured heat pipe may vary, which is not desirable.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a practical method for manufacturing a heat pipe, which enables efficient manufacturing with excellent workability. That is, the method of manufacturing a heat pipe of the present invention includes a step of injecting a working fluid from the other end of the pipe body having one end sealed, and the other end from a plurality of directions using a male mold and a female mold. A method of manufacturing a heat pipe including a step of caulking by crushing a plurality of times and a step of welding and sealing the other end. Prior to the step of injecting the working fluid, a step of reducing the diameter of the other end of the pipe body whose one end is sealed may be performed.

Preferably, the caulking step is performed a plurality of times by setting the direction in which the ends are crushed by the male mold and the female mold alternately and substantially vertically.

[0010]

FIG. 1 is a schematic diagram for explaining a caulking step in a method of manufacturing a heat pipe according to the present invention. Although not specifically mentioned in the following description, it goes without saying that the inside of the pipe body 20 is subjected to cleaning, degassing, and the like in the manufacturing process of the heat pipe. After the pipe body 20 is sealed, plating or the like may be further performed or bent. In FIG. 1, the cross section of the pipe body 20 is drawn by omitting the illustration of the internal cavity. Also, for the sake of brevity, the shapes of the pipe body 20, the male dies 10, 12, 14 and the female dies 11, 13, 15 are schematically illustrated.

A pipe body having one end sealed and having a predetermined amount of working fluid injected therein is prepared, and the other end thereof is sealed. A pipe body 20 shown in FIG. 1A shows an end portion of the pipe body on an unsealed side. As shown in FIG. 1A, the male mold 10 and the female mold 1
Crush with both dies. Then, pipe body 2
As shown in FIG. 1B, the male mold 12 and the female mold 1 are shifted from the arrangement direction of the male mold 10 and the female mold 11 by about 90 °.
3 crushes the pipe body 20 again. Further, this time, the pipe body 20 is squashed by the male mold 14 and the female mold 15 as shown in FIG. . In this manner, the pipe body 20 is crushed by the male mold and the female mold by shifting by about 90 °, and the end of the pipe body 20 is swaged.

The end of the pipe body 20 caulked as described above is in a temporarily sealed state. That is, if the pipe body 20 is excessively heated, the internal pressure increases and the seal is broken, but in a very short time, the pipe body 20
The cavity inside is substantially sealed. In this state, sealing may be performed as soon as possible by TIG welding or the like.

In the above example of the crimping step, the work of crushing with the male mold and the female mold is performed three times, but the number is arbitrary. In the above example, the shift angle in the front and rear crushing directions is set to about 90 °, but this angle may be set to about 90 °. Basically, it is desirable to shift by 90 ° from the viewpoint of the reliability of the temporary sealing.

In the caulking step, the number of times of crushing and the caulking force may be appropriately set according to the size and material of the pipe body 20. It is also effective to reduce the diameter of the crushed end prior to the above-described crimping step.

FIG. 2A is a diagram schematically showing the end shape of the pipe body 20 which has been subjected to the caulking step in the present invention. Assuming that the diameter of the pipe body 20 before caulking is D, the diameter of the tip portion after caulking is d, and the radius of the illustrated portion of the caulked portion is R or r, it is preferable to substantially satisfy the following equation ( FIG. 2B is an enlarged view of R and r in FIG. 2A. That is, 1/3 × D ≦ d ≦ 1/2 × D, 1 /
4 × D ≦ R ≦ １ ／ × D, 1/3 × R ≦ r ≦ R. When caulking is performed so as to satisfy this condition, the temporary sealing is more reliably performed, which is desirable.

According to the method for manufacturing a heat pipe of the present invention as described above, a heat pipe having excellent pressure resistance of the sealing portion and having stable performance and durability can be obtained. In addition, the sealing operation can be performed efficiently.

[0017]

As described above in detail, the method for manufacturing a heat pipe according to the present invention can provide an excellent heat pipe and also contributes to the manufacturing cost thereof.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a main part of a method for manufacturing a heat pipe according to the present invention.

FIG. 2 is a view showing an example of an end shape of a pipe body subjected to a caulking step in a method of manufacturing a heat pipe of the present invention.

[Explanation of symbols]

 10 Male type 11 Female type 12 Male type 13 Female type 14 Male type 15 Female type 20 Pipe body

Claims (3)

[Claims] 1. A step of injecting a working fluid from the other end of a pipe body having one end sealed, wherein said other end is crushed a plurality of times from a plurality of directions by a male mold and a female mold. A method for manufacturing a heat pipe, comprising a step of caulking and a step of welding and sealing the other end. 2. A step of reducing the diameter of the other end of the pipe body having one end sealed, a step of injecting a working fluid from the reduced diameter of the other end, and using a male mold and a female mold. Caulking by squashing the other end a plurality of times from a plurality of directions,
A method for manufacturing a heat pipe, comprising a step of welding and sealing the other end. 3. The method according to claim 1, wherein, in the caulking step, the direction in which the ends are crushed by the male mold and the female mold is alternately set to be substantially vertical, and is performed a plurality of times. A method for producing the heat pipe described in the above.