JPH1073384A - Manufacture of u-shaped heat pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a U-shaped heat pipe with a sufficient heat characteristic by opening both ends of a U-shaped metal pipe to accurately deaerate the inside of the U-shaped metal pipe on both hands thereof separately. SOLUTION: A metal pipe 20 which has a groove formed on the inner circumferential surface thereof by an extrusion working is cut to a specified length. An intermediate part 21 of the pipe is bent almost at the right angle by a bending device to form a U-shaped metal pipe 20A. This pipe undergoes a compression working being opened in the form of a nozzle, for example, with a split mold jig to form a U-shaped metal pipe 20B. A working liquid 23 is injected into the U-shaped metal pipe 20B and the intermediate part 21 thereof is placed into a heated oil bath 25 to deaerate the inside of the U-shaped metal pipe 20B thereby enabling accurate deaeration of both hands of the U-shaped pipe separately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently manufacturing a U-shaped heat pipe.

[0002]

2. Description of the Related Art A heat pipe is a pipe in which a working fluid such as water is put in a metal pipe which has been decompressed. When one of the pipes is heated, the working fluid turns into steam and flows to the other. A good thermal conductor in which liquid returns to a heating portion and conducts heat by capillary action such as a wick or a groove disposed in a metal pipe, and has conventionally been used for cooling a heating portion. This heat pipe is used as a cooler 30, for example, as shown in FIG. The cooler 30 is configured by embedding a plurality of heat pipes 31 in a copper plate 32, arranging the plurality of heat pipes 31 vertically, and mounting a plurality of metal radiating fins 33 above the heat pipe 31.
The cooler 30 removes heat from the heating element 33 by attaching a heating element 33 made of a device such as a thyristor to a copper plate 32.

[0003]

In recent years, electronic devices and power devices equipped with devices such as transistors and thyristors tend to be highly integrated and have a large capacity, and the amount of heat generated has also increased. In the case of cooling a power device generating a large amount of heat, a high-performance cooler capable of rapidly and uniformly transporting a large amount of heat is required. The cooler 30 using the conventional heat pipe 31 shown in FIG.
Since the one heat absorbing portion is in a state of being buried in the copper plate 32 in a point manner, the above requirements cannot be sufficiently satisfied in terms of uniformity and quickness.

[0004] To meet the above demand, a cooler 40 as shown in FIG. 4 has been proposed. This cooler 40
Since the heat absorbing portion 42 at the intermediate portion of the U-shaped heat pipe 41 shown in FIG. 5 is embedded in the copper plate 43, the contact portion between the copper plate 43 and the heat absorbing portion 42 of the U-shaped heat pipe 41 becomes large, As a result, a large amount of heat can be quickly and uniformly transported. In FIG. 4, reference numeral 44 denotes a metal radiating fin.

[0005] The U-shaped heat pipe 41 used in the cooler 40 is manufactured as follows. A metal pipe formed with a groove on the inner peripheral surface manufactured by a method such as extrusion processing is cut into a predetermined length, one end is sealed by TIG welding, a working fluid is injected from the other end side, and then the inside of the metal pipe is cleaned. While degassing, the other end of the metal pipe is compressed into a conical shape by drawing, and the compressed portion is blown off by a laser. The melt section is melted and the inside of the metal pipe is sealed in a vacuum to form a long linear heat pipe. A U-shaped heat pipe is manufactured by bending both sides of the straight heat pipe at substantially right angles while keeping the middle portion of the heat pipe substantially straight.

[0006] This manufacturing method has the following disadvantages. In other words, in order to process a once-formed linear heat pipe, it must be carefully handled and the work efficiency does not increase. In addition, as a result of careful processing so as not to crush the inside of the pipe at the time of bending at a right angle, the radius of the bent portion is not formed uniformly, and when embedding a plurality of heat pipes in the copper plate 43, an irregular U-shaped There is a problem that the heat pipe 41 will be used.

In order to solve the above problems,
Other U-shaped heat pipe manufacturing methods have been proposed.
In this method, a metal pipe formed with a groove on the inner peripheral surface manufactured by a method such as extrusion processing is cut into a predetermined length, one end of which is sealed by TIG welding, and an intermediate portion thereof is kept substantially linear. Thus, both sides are bent at substantially right angles as shown in FIG. 6 to form a U-shaped metal pipe 51.

[0008] Since this method does not process the completed heat pipe, its handling is not special.
Since there is no problem in ordinary processing, the handling is easy, and a product which can sufficiently meet dimensional accuracy can be processed. The working fluid is injected from the other open end of the U-shaped metal pipe 51 formed as described above, and then the U-shaped bottom portion is heated to degas the inside of the metal pipe 51. afterwards,
The other end of the metal pipe 51 is compressed into a conical shape by drawing, and the compressed portion is blown off by a laser. The melted section is melted and the inside of the metal pipe is sealed in a vacuum, and the U-shaped heat pipe 41 is manufactured.

Although this U-shaped heat pipe is sufficiently satisfactory in dimensional accuracy, it has the following disadvantages. When the working fluid is injected from the other open end of the U-shaped metal pipe 51 and heated to degas the inside of the metal pipe 51, the inside of the metal pipe 51 on the sealed side is completely removed. It was found not to be degassed. That is, as shown in FIG. 7, the air on the sealed side is delayed since there is no passage for deaeration as long as the injected working fluid 52 remains on the sealed side. Since deaeration is completed at the other end that is open during that time, compression processing is started at the other end that is open at the time of completion, and the compressed portion is blown out by the laser. As a result, the metal pipe 5 on the sealed side
Since the degassing in 1 is incomplete, a U-shaped heat pipe having insufficient heat characteristics results.

An object of the present invention is to solve the above-mentioned problems and to provide a method for manufacturing a U-shaped heat pipe which can guarantee dimensional accuracy and has good thermal characteristics.

[0011]

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

According to a first aspect of the present invention, there is provided a method for manufacturing a U-shaped heat pipe, wherein a metal pipe having a predetermined length with both ends opened is bent into a substantially U-shape, and at least one end of the metal pipe is formed. The working fluid is injected, and then both ends of the metal pipe are compressed while the inside of the metal pipe is degassed, and the compressed portion is melted and sealed.

[0013] In the method for manufacturing a U-shaped heat pipe according to the second aspect of the present invention, before injecting the working fluid into the metal pipe,
It is characterized in that both ends of the metal pipe are compression-processed so as to open in a nozzle shape.

According to the method of manufacturing a U-shaped heat pipe according to the first aspect of the present invention, since the metal pipe formed in a U-shape is open at both ends, a working fluid is injected into the metal pipe to form a metal pipe. When the inside of the pipe is degassed, both ends of the metal pipe are degassed. Therefore, degassing is reliably achieved on both sides of the U-shape. By compressing and sealing each end after degassing, a U-shaped heat pipe having sufficient thermal characteristics is manufactured. In addition, since the U-shaped processing is performed at the stage of the metal pipe before it becomes a heat pipe, its handling is also easy, it can be performed by normal bending processing, and a dimensional accuracy that can sufficiently meet the demand. it can.

According to the method of manufacturing a U-shaped heat pipe according to the second aspect of the present invention, since both ends of the metal pipe are compressed in the form of a nozzle, it is easy to compress each end after degassing. Becomes

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a method for manufacturing a heat pipe according to the present invention will be described below in more detail with reference to FIG. 1 or FIG. FIG. 1 shows a U-shaped heat pipe 10 manufactured by the heat pipe manufacturing method of the present invention. The U-shaped heat pipe 10 has a middle portion bent at a substantially right angle to form a U-shape, and a U-shaped bottom portion serves as a heat absorbing portion 11. Both ends 1 of U-shaped heat pipe 10
2 is sealed, and a well-known working fluid is sealed inside the heat pipe 10 in a sealed state.

A method of manufacturing the above-mentioned U-shaped heat pipe 10 will be described below. As shown in FIG. 2A, a metal pipe 20 having a groove formed on an inner peripheral surface manufactured by a method such as extrusion processing is cut into a predetermined length. Metal pipe 2
As shown in FIG. 2B, the intermediate portion 21 is bent at a substantially right angle by a known bending machine (not shown) to form a U-shaped metal pipe 20A. Both ends 22 of the U-shaped metal pipe 20A are compression-processed into a state of being opened in a nozzle shape by, for example, a split jig to form a U-shaped metal pipe 20B as shown in FIG.

As shown in FIG. 2 (D), a working fluid 23 is injected into a U-shaped metal pipe 20B which has been compressed so that both ends are opened in the shape of a nozzle.
5 and the inside of the U-shaped metal pipe 20B is evacuated. As the working fluid 23, a known heat medium such as well-known water, alcohols, non-polluting freon, and antifreeze can be applied. When deaeration inside the metal pipe 20B is completed, FIG.
As shown in the figure, the both ends 22 are sealed and compressed in a conical shape by, for example, a split jig, and then the compressed portion is melted into a substantially arc shape by, for example, TIG welding to form an end portion 12 to form a U-shaped heat pipe. Complete 10

[0019]

As described above, according to the method for manufacturing a U-shaped heat pipe according to the first aspect of the present invention, since the metal pipe formed into a U-shape has both ends open, When the working fluid is injected into the metal pipe to degas the inside,
Both ends of the metal pipe are degassed. Therefore, the inside of the metal pipes on both sides of the U-shape can be reliably degassed. By compressing and sealing each end after the deaeration, the U-shape having sufficient thermal characteristics is obtained. Heat pipes are manufactured. In addition, since the U-shaped processing is performed at the stage of the metal pipe before it becomes a heat pipe, its handling is also easy, it can be performed by normal bending processing, and a dimensional accuracy that can sufficiently meet the demand. it can.

According to the method of manufacturing a U-shaped heat pipe according to the second aspect of the present invention, since both ends of the metal pipe are compressed in the form of a nozzle, compression of each end after degassing is easy. Becomes

[Brief description of the drawings]

FIG. 1 is a front view of a U-shaped heat pipe manufactured by one embodiment of a method for manufacturing a U-shaped heat pipe according to the present invention.

FIGS. 2A to 2E are explanatory views showing the steps of a method for manufacturing a U-shaped heat pipe according to an embodiment of the present invention.

FIG. 3 is a perspective view showing an example of a cooler using a conventional heat pipe.

FIG. 4 is a perspective view showing an example of a cooler using a U-shaped heat pipe.

FIG. 5 is an explanatory diagram showing an example of a U-shaped heat pipe.

FIG. 6 is an explanatory view showing one step of a conventional method of manufacturing a U-shaped heat pipe.

FIG. 7 is an explanatory view showing one step of a conventional method for manufacturing a U-shaped heat pipe.

DESCRIPTION OF SYMBOLS 10 U-shaped heat pipe 11 Heat-absorbing part 12 End 20 Metal pipe with groove formed on inner peripheral surface 20A U-shaped metal pipe 20B U-shaped metal pipe with both ends opened in nozzle shape 21 Intermediate part 22 End of metal pipe 23 Hydraulic fluid 25 Oil bath

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Murase 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd.

Claims (2)

[Claims] 1. A metal pipe having a predetermined length with both ends open is bent to form a substantially U-shape, a working fluid is injected from at least one end of the metal pipe, and then the inside of the metal pipe is degassed. A method of manufacturing a U-shaped heat pipe, comprising compressing both ends of the metal pipe and melting and sealing the compressed portion. 2. The U-shaped heat pipe according to claim 1, wherein before the working fluid is injected into the metal pipe, the metal pipe is compression-processed so that both ends of the metal pipe are opened in a nozzle shape. Production method.