JPH09324993A - Manufacturing method of heat pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing heat pipes at low cost by simplifying manufacturing processes, reducing a number of processes and enhancing the productivity. SOLUTION: A heat pipe 10 is constructed such that a working liquid 11c hermetically fills a metallic tube 11 which has both ends sealed. While holding the heat pipe 10 substantially horizontally, the cross-sectional area of the heat pipe 10 is reduced in diameter at given positions in a lengthwise direction such that the inner walls of the heat pipe 10 are made come into contact with each other in such positions. Subsequently, the heat pipe 10 is cut and divided such that the diameter-reduced portions where the inner walls are made come into contact with each other remain at both ends of each divided heat pipe. The cut end faces of the divided heat pipes are welded and sealed so as to manufacture divisional heat pipes from the heat pipe 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pipe manufacturing method, and more particularly, by dividing a preliminarily manufactured long heat pipe, manufacturing of the heat pipe is facilitated and cost reduction is achieved by improving productivity. The present invention relates to a possible heat pipe manufacturing method.

[0002]

2. Description of the Related Art In recent years, electronic devices such as ICs and LSIs have been incorporated in high density, and the electronic devices themselves have been downsized. With this higher density and smaller size,
Local heat generation of electronic devices is increasing. Therefore, there is a demand for a technique for efficiently radiating the local heat generated by the electronic device. In order to meet such a demand, a method of cooling an element incorporated in an electronic device using a heat pipe has been proposed. For example, it is a method in which a relatively small heat pipe having an outer diameter of about 3 mmφ is thermally connected to the element and the metal substrate to radiate heat to the entire substrate. This heat pipe is used in a state in which a predetermined amount of a working liquid is injected into a metal pipe such as Cu having a wick formed therein, and the both ends are sealed and kept under reduced pressure.

Conventionally, as a method of manufacturing such a relatively thin heat pipe, a metal pipe such as Cu is prepared in advance, cut into a predetermined length, and one end is sealed by means such as welding. Cut. After that, deaeration is performed from one end side, the working fluid is injected, and finally, sealing is performed by a method such as ultrasonic welding. Then, the vicinity of the center of the welded portion is mechanically cut, and if necessary, the cut end surface is shaped into a circle to obtain a heat pipe of a desired size.
In addition to ultrasonic welding, brazing is partly used as a sealing method. These steps are generally performed independently of each other, and often include various steps such as straightening, pickling, and reducing in order to improve the characteristics of the heat pipe.
In particular, it is difficult to manage and control the injection amount of the hydraulic fluid, and to perform deaeration work prior to or simultaneously with the injection.

[0004]

As described above, a method for manufacturing a heat pipe having a relatively small diameter, in which the working fluid is injected and sealed in each metal tube cut into a predetermined length, is However, there are drawbacks in that not only the number of steps is time-consuming and time-consuming, but also extremely complicated and expensive.

An object of the present invention is to solve the above problems and to provide a method for manufacturing a heat pipe at a low cost by simplifying the manufacturing process and reducing the number of processes to improve the productivity. is there.

[0006]

The present invention has the following means to solve the above problems.

In the method for manufacturing a heat pipe according to claim 1 of the present invention, the heat pipe in which the working liquid is hermetically injected into the metal pipe whose both ends are sealed is held substantially horizontally and the length direction The cross-sectional area is reduced so that the inner wall surface of the pipe is in close contact at a predetermined position along the line, and the cutting end face is melted by dividing and cutting so that the part where the inner wall surface of the pipe is in close contact remains on both sides. , And manufacturing a plurality of divided heat pipes from the heat pipe.

The heat pipe manufacturing method according to the second aspect of the present invention is characterized in that the processing for reducing the diameter of the inner wall surface of the tube in a closely contacted state is pressing or drawing using a split jig.

In the method for manufacturing a heat pipe according to a third aspect of the present invention, the process of reducing the diameter of the inner wall surface of the pipe to a close contact state is performed by using a rotary chuck.

According to a fourth aspect of the present invention, the heat pipe manufacturing method is characterized in that the diameter of the inner wall surface of the pipe is reduced by bringing the metal pipe into contact with each other by rotating both ends or one end of the metal pipe. To do.

In the method for manufacturing a heat pipe according to a fifth aspect of the present invention, in the processing for reducing the inner wall surface of the pipe to a closely contacted state, tension is applied while locally heating the metal pipe so that the metal pipe is in a molten state or a semi-molten state. It is characterized in that it is given to reduce the diameter.

According to the method for producing a heat pipe of the present invention, a plurality of heat pipes are produced by dividing and cutting the completed heat pipe while keeping it airtight.
Injecting hydraulic fluid into metal tubes cut into a predetermined length for each one,
Compared with the conventional heat pipe manufacturing method in which the sealing is performed, the number of times of degassing and liquid volume control, which take time during the manufacturing process, is reduced, and the manufacturing process is significantly simplified. Since the number of steps is reduced, the productivity is improved, and as a result, the heat pipe can be manufactured at low cost.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for manufacturing a heat pipe according to the present invention will be described in detail with reference to an embodiment shown in FIGS. FIG. 1 shows a heat pipe 10 manufactured by a conventionally known method. As a conventional method, for example, FIG.
As shown in (1), one end 11a of the metal pipe 11 having a predetermined length is completely sealed by a method such as welding to make a sealed state. Metal tube 11
A plurality of grooves are provided on the inner peripheral surface of the. The predetermined length referred to in the present embodiment has a length that is a multiple of that of the split heat pipe 20 shown in FIG. 3 manufactured in the present embodiment. In addition, the metal tube 11 is pickled beforehand if necessary.

After that, the inside of the metal tube 11 is degassed from the open end 11b, the working fluid 11c is injected and filled, and further, a predetermined position is sealed off by a method such as ultrasonic welding to make a sealed state and a long length. Obtain the heat pipe 10. The cross-sectional area of the heat pipe 10 is reduced so that airtightness can be maintained over a predetermined length at a desired position in the lengthwise direction, that is, the inner wall surface of the pipe is in a close contact state. As a method of reducing the diameter, for example, an appropriate method as shown in FIGS. 4 (a) to 4 (d) can be applied.

In the method of reducing the diameter shown in FIG. 4 (a), the split die 12 is used for press working or drawing to make a cross section substantially circular and polygonal as shown by the arrow in FIG. 4 (a). The diameter is reduced so as to have a shape.

The method of reducing the diameter shown in FIG. 4B is to reduce the diameter using a jig such as a rotary chuck (not shown). The number of chucks is, for example, as shown in FIG.
As shown by the arrow (b), the diameter can be reduced from three directions so that the cross-sectional shape becomes a triangular shape, and it is also possible to reduce the diameter from four directions, five directions, or more. However,
The caulking in which the diameter is reduced from two directions is not preferable because there is a possibility that the reliability of maintaining the airtightness until the next melt-sealing may be reduced.

Further, as shown in FIG. 4C, the diameter can be partially reduced by rotating both ends or one end of the heat pipe 10. Furthermore, FIG.
This is an example of a method in which the material of the heat pipe 10 is locally heated so as to be in a molten state or a semi-molten state, and a slight tension is applied to reduce the diameter. In the method of FIG. 4 (a) or FIG. 4 (b), for example, as shown in FIG.
For example, if it is rotated by 60 ° and the diameter is reduced again in the same manner to form the circular reduced diameter portion 14, it becomes possible to improve the reliability of airtightness. The number of times is not limited, but if the number is too large, the processing time becomes long, so about 1 to 3 times is preferable. When a rotary chuck is used, it is effective to use a pneumatic type, a hydraulic type, an electric type, or the like because the diameter reduction process can be automated.

When the diameter is reduced as shown in FIG. 4C, it is possible to reduce the diameter while heating at room temperature or locally. As a heating method in the method of FIG. 4C or 4D, for example, high frequency induction heating, infrared heating, laser heating, electron beam heating, or the like can be applied. In this case, in order to prevent oxidation of the heat pipe 10, it is desirable to carry out in an inert gas atmosphere or in an air stream. Since it is preferable that the working fluid inside the heat pipe 10 is uniform, the diameter reducing step described above is performed in a state of being held horizontally.

Further, the above-mentioned FIG. 4 (a) to FIG. 4 (d).
Regarding the diameter reduction shown in the above, the case where the diameter reducing portion is one location has been described, but the diameter reduction is not limited to the above, but two locations or three
The diameters may be reduced at the same time. Then, the reduced diameter portion is cut and divided. As a method of division cutting, a method using a cutter using a normal blade, shearing, or a laser can be appropriately adopted.

At the time of cutting and dividing, the divided heat pipe 20 shown in FIG. 3 is obtained by dividing and cutting so that the inner wall surface of the metal tube 11 is reduced in a closely contacted state on both sides. There is no restriction on the length of the reduced diameter portion after the division, but it is better to leave a little for the melt sealing process of the end portion described later. It goes without saying that the length of each divided heat pipe 20 that is divided and manufactured can be set arbitrarily. In addition to having the same length, different lengths can be set. in this case,
For example, the length of the split heat pipe 20 can be controlled on the order of mm, which is advantageous in that it can be applied to manufacturing heat pipes of various lengths.

In order to maintain long-term reliability or high-temperature breaking strength of the heat pipe 20 divided by the above-mentioned method, the cut surface of the end portion is melted. The melting method is, for example, TI
Normal welding means such as G welding can be applied as it is. It goes without saying that, after melting, shaping the portion into a circular shape to adjust the appearance is also an effective means in terms of design. It is also possible to continuously automate the subsequent steps including the diameter reduction. As described above, according to the method for manufacturing a heat pipe of the present invention, it is possible to divide a relatively long heat pipe into a large number of heat pipes, thereby reducing the manufacturing cost. It is also possible to manufacture heat pipes of irregular length and irregular length. Hereinafter, the method for manufacturing the heat pipe of the present invention will be described more specifically based on examples.

(Embodiment 1) Using a copper tube having an outer diameter of 3 mmφ having 20 grooves inside, an inner diameter of 2.4 mmφ at the bottom of the groove, and a length of 550 mm, a length of 500 mm was obtained by a conventionally known method. A long heat pipe 10 was manufactured. By using the method shown in FIG. 1A, the long heat pipe 10 was held in a horizontal state, and the split jig 12 was used to reduce the diameter of the heat pipe 10 into a substantially circular cross section. The length of the diameter reduction processing was 5 mm, and the outer diameter was about 1.5 mmφ. The center portion subjected to the diameter reduction processing was cut into two parts with a cutter using a normal blade. The cut end faces were TIG-welded to manufacture two short split heat pipes 20. In addition, the diameter reduction processing by the split mold jig 12 was performed once. FIG. 6 shows the shape of the divided tip 15. As a result of conducting a thermal inspection on the obtained two divided heat pipes 20, both showed a healthy operation.

(Embodiment 2) The heat pipe 10 manufactured under the same conditions as in Embodiment 1 was held by the method shown in FIG. The diameter was reduced so that the cross section had a substantially triangular shape. The diameter of the reduced diameter is 5mm, and the length of one side is about 1.5.
It was mmφ. The center portion subjected to the diameter reduction processing was cut into two parts with a cutter using a normal blade. The cut end faces were TIG-welded to produce two split heat pipes 20. As a result of the heat inspection, both of them showed a sound operation.

(Embodiment 3) Under the same conditions as in Embodiment 2, the heat pipe 10 manufactured under the same conditions as in Embodiment 1 is reduced in diameter in a triangular shape by using a three-way chuck, and then the second reduction treatment is performed. I went. In the second diameter reduction processing, the portion subjected to the diameter reduction processing was rotated about 30 ° and the diameter was again reduced to a substantially circular shape. Reduced length is 5mm, outer diameter is about 1.5mmφ
Met. The center portion subjected to the diameter reduction processing was cut into two parts with a cutter using a normal blade. Both ends cut are TIG
Two split heat pipes 20 were manufactured by welding. As a result of the heat inspection, both of them showed a sound operation.

(Example 4) The heat pipe 10 manufactured under the same conditions as in Example 1 was held at the horizontal state by the method shown in Fig. 4C, and one end (left side) was rotated. Then, the diameter was reduced. The outer diameter after the diameter reduction processing was about 1.5 mmφ. YAG near the center of reduced diameter
It was cut using a laser and divided into two pieces. Also in the case of this example, TIG welding was performed and the end face shape was as shown in FIG.
As a result of the heat inspection, the two split heat pipes 20 were both good products, and the effect of the heat pipe manufacturing method of the present invention was clarified.

(Embodiment 5) The heat pipe 10 manufactured under the same conditions as in Embodiment 1 was held by the method shown in FIG. Was locally softened by applying a tension to reduce the diameter. In this case, it was performed in an Ar stream. Then Example 1
In the same manner as above, cutting with a cutter and TIG welding were performed to divide into two pieces. As a result of performing a liquid amount inspection and a heat inspection on the obtained split heat pipe 20, both were good products.

(Sixth Embodiment) The heat pipe 10 manufactured under the same conditions as in the first embodiment is held in a horizontal state, as shown in FIG.
By the method shown in (a), the split mold jig 12 was used to reduce the diameter so that the cross section was formed into two substantially circular shapes as shown in FIG. The diameter-reduced portion 16 had a length of 5 mm and an outer diameter of about 1.5 mmφ. The central portion of the reduced diameter processing portion 16 was cut into three parts by a cutter using a normal blade. 150mm, 200m in length by TIG welding the cut both ends
Three short heat pipes 20 of m and 150 mm were manufactured. As a result of performing a liquid amount test and a heat test on the obtained split heat pipes 20, all three were good products.

[0028]

As described above, according to the method for manufacturing a heat pipe of the present invention, a plurality of heat pipes are produced by dividing and cutting the heat pipe while keeping airtightness. Compared with the conventional heat pipe manufacturing method that injects and seals a working fluid into a metal tube that has been cut to a predetermined length, the number of degassing and liquid volume control operations that take time during the manufacturing process is less As a result, the manufacturing process is remarkably simplified, the productivity is improved by the reduced number of processes, and as a result, the heat pipe can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a heat pipe manufactured by a conventional method used in the heat pipe manufacturing method of the present invention.

FIG. 2 is a cross-sectional view showing a step in the state of manufacturing a heat pipe used in the method for manufacturing a heat pipe of the present invention by a conventional method.

FIG. 3 is a cross-sectional view showing an example of a heat pipe manufactured by the method for manufacturing a heat pipe of the present invention.

FIG. 4 (a) to FIG. 4 (d) are explanatory views showing respective embodiments of diameter reduction processing which is one step of the method for manufacturing a heat pipe of the present invention.

FIG. 5 is a cross-sectional view of a reduced diameter portion formed by the heat pipe manufacturing method of the present invention.

FIG. 6 is an explanatory view showing an end portion of a short heat pipe manufactured by the heat pipe manufacturing method of the present invention.

FIG. 7 is an explanatory view showing a reduced diameter portion formed by the heat pipe manufacturing method of the present invention.

[Explanation of symbols]

 10 heat pipe 11 metal pipe 11c hydraulic fluid 12 split jigs 13 and 14 reduced diameter portion 20 split heat pipe

Claims (5)

[Claims] 1. A heat pipe, in which a working fluid is hermetically injected into a metal pipe whose both ends are sealed, is held substantially horizontally, and the inner wall surface of the pipe is in close contact at a predetermined position along the length direction. To produce a plurality of split heat pipes from the heat pipe by dividing and cutting the inner wall surface of the pipe so that portions of the pipe inner wall that have been reduced in diameter are left on both sides, and the cut end faces are melted and sealed. A method for manufacturing a heat pipe, comprising: 2. The processing for reducing the diameter of the inner wall surface of the pipe to a close contact state,
The method for manufacturing a heat pipe according to claim 1, wherein the heat pipe is pressed or drawn using a split jig. 3. The processing for reducing the diameter of the inner wall surface of the pipe to a close contact state,
The method for manufacturing a heat pipe according to claim 1, wherein the method is performed using a rotary chuck. 4. The processing for reducing the diameter of the inner wall surface of the pipe to a close contact state,
The heat pipe manufacturing method according to claim 1, wherein the diameter of the metal pipe is partially reduced by rotating both ends or one end of the metal pipe. 5. The processing for reducing the diameter of the inner wall surface of the pipe to a close contact state,
The method for producing a heat pipe according to claim 1, wherein the metal pipe is locally heated so as to be in a molten state or a semi-molten state, and tension is applied to reduce the diameter.