JP2002022380A - Flat plate shaped heat pipe equipped with emboss wick - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat plate shaped heat pipe equipped with an emboss wick that is simplified and is easy in mass production. SOLUTION: In a flat plate shaped heat pipe where substantially only condensed fluid is encapsulated in a flat plate shaped hollow container 1, the foregoing hollow container 1 is formed with a flat plate shaped lower cover 2 and a flat plate shaped upper cover 3 having a recessed portion 4 recessed toward the foregoing flat plate shaped lower cover 2, and a porous sheet 5 is formed on an internal surface of the flat plate shaped upper cover 3 having the foregoing recessed portion 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pipe for transferring heat as latent heat of vaporization of a working fluid, and more particularly to a heat pipe in which a container in which a condensable working fluid is sealed has a flat plate shape.

[0002]

2. Description of the Related Art A flat heat pipe has a closed space formed by a container having a hollow flat plate structure. In the space, a non-condensable gas such as air is degassed and a condensable fluid is used as a working fluid. It is enclosed. This type of heat pipe has a flat surface, so the contact area with the heat exchange object is increased, resulting in improved heat transfer performance or heat exchange performance, and when used as a cooling means. Has such an advantage that a wide heat radiation area can be secured.

On the other hand, since the heat pipe has a structure in which only a condensable fluid is sealed in the closed space, the working fluid is condensed in a non-operating state or a cooling state in which no heat is input from the outside. The inside of the section becomes a high vacuum state. Conversely, if a large amount of heat is input from the outside, the working fluid evaporates and its volume increases, so that the internal pressure of the closed space increases. Therefore, in the flat heat pipe, the rigidity of the upper surface and the lower surface where the surface area is large is low, so that the upper surface and the lower surface are deformed to be depressed at the time of non-operation or at the time of manufacturing, or to the contrary. At times, deformation such as swelling of the upper and lower portions may occur.

In order to solve such inconvenience, in the invention described in Japanese Patent Application Laid-Open No. H11-287578, a plurality of columnar portions are integrally erected inside a thin container having an open upper end. A porous film that functions as a wick is formed by thermal spraying inside the container, and the opening of the container is then sealed. Has been proposed as a flat heat pipe in which is sealed as a working fluid.

[0005]

The flat-plate heat pipe described in the above publication has a structure in which a plurality of columnar portions are connected to a bottom surface portion and a top surface portion having a large area.
It is possible to prevent the dent deformation of the bottom portion and the upper surface portion when the internal pressure is reduced, and the swelling deformation of the bottom portion and the upper surface portion due to the increase of the internal pressure during operation. However, since the pillars are integrally formed inside a thin container, the structure of the container becomes complicated, and the productivity must be deteriorated. In addition, the flat heat pipe has a configuration in which a porous film functioning as a wick is formed by thermal spraying on the inner surface of a thin container having a plurality of columnar portions therein, thereby complicating the manufacturing process. Not only that, work with a low material yield was inevitable, and as a result, the productivity of the flat heat pipe was poor, and the production cost was high.

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical problems, and has as its object to provide a flat heat pipe which has good productivity and can be reduced in cost. is there.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, a first aspect of the present invention is a flat plate heat pipe in which substantially only a condensable fluid is sealed in a flat hollow container. In the above, the hollow container is formed by a flat lower lid and a flat upper lid having a concave portion recessed toward the flat lower lid, and a flat upper lid having the concave portion A flat heat pipe provided with an emboss wick, wherein a porous sheet is formed on the inner surface of the heat pipe.

Therefore, according to the first aspect of the present invention, a flat container can be formed by joining and integrating the flat upper lid and the flat lower lid. In order to make this into a heat pipe, ordinary degassing and sealing of the working fluid may be performed. Then, the porous sheet formed on the inner surface of the flat upper lid functions as a wick. Thus, according to the first aspect of the invention, it is possible to manufacture the container by laminating and fixing a plurality of parts,
The manufacturing workability is improved.

According to a second aspect of the present invention, in the configuration of the first aspect, the concave portion is located substantially at a center in a width direction of the flat upper cover and a longitudinal direction of the flat upper cover. A flat heat pipe provided with an emboss wick, wherein a plurality of the heat pipes are provided at predetermined intervals.

Therefore, according to the second aspect of the present invention, the concave portion formed in the flat upper lid can support the upper and lower portions of the hollow container as a support. As a result, deformation of the container at the time of manufacturing, non-operation, or operation can be prevented. Further, since the concave portion is formed integrally with the flat upper lid, the container can be manufactured by fixing the flat upper and lower lids as in the invention of claim 1. The manufacturing workability is improved.

Further, according to a third aspect of the present invention, there is provided the embossed wick according to the first or second aspect, wherein the concave portion is provided in contact with the flat lower lid. It is a flat plate type heat pipe provided.

Therefore, according to the third aspect of the present invention, the deformation of the container during manufacture, non-operation, or operation can be reliably prevented by contacting the concave portion with the flat lower lid.

According to a fourth aspect of the present invention, in the configuration of the first to third aspects, the porous sheet is embossed according to an inner shape of the flat upper cover. It is a flat heat pipe with an emboss wick.

Therefore, according to the fourth aspect of the present invention, the rigidity of the upper and lower lids having a large area is increased by embossing and fixing the porous sheet according to the shape of the inner surface of the flat upper lid. The deformation can be reliably prevented or suppressed, and at the same time, the recirculation or dispersibility of the working fluid to the inner surfaces of the upper and lower lids can be improved, and the heat transport ability can be improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a specific example of a flat heat pipe having an emboss wick according to the present invention will be described with reference to the drawings. First, the structure of the container (container) 1 will be described. In FIG. 1, the flat lower lid 2 is a thin plate made of a metal having good heat conductivity such as copper, and in the example shown in FIG. Is formed. Further, a concave portion 4 is provided in the flat upper cover 3 that matches the flat lower cover 2.

The concave portion 4 is formed by embossing, for example, and has a truncated conical cross section, and has a side wall 5 and a bottom wall 6. Further, the bottom wall portion 6 of the concave portion 4 has a structure in which the bottom wall portion 6 is in close contact with the flat lower lid 2. Further, a plurality of the concave portions 4 are provided substantially at the center in the width direction of the plate-like upper cover 3 and at regular intervals in the length direction of the plate-like upper cover 3.

Further, a porous sheet 7 is attached inside the flat upper cover 3. The porous sheet 7 is for forming a porous layer that functions as a wick for generating a capillary pressure to flow a working fluid described later, and is formed by sintering fine particles of metal or ceramics. ing. The porous sheet 7 has an outline conforming to the shape of the inside of the flat upper cover 3, that is, a rectangular shape as a whole and a portion corresponding to the concave portion 4. Is formed with a recessed portion 8 recessed in accordance with these contours. The porous sheet 7 having such a depression 8 can be manufactured by embossing, for example.

The heat pipe container 1 according to the present invention comprises:
The upper and lower plate-like lids 2 and 3 are fixedly integrated. That is, the porous sheet 7 is laminated and fixed inside the flat upper cover 3. This is because, for example, the flat upper cover 3 is made of copper and the porous sheet 7
Is formed by sintering copper fine particles, the porous sheet 7 is heated to a predetermined temperature with the porous sheet 7 placed on the inside of the plate-like upper cover 3, and the two are fixedly integrated by sintering. be able to.

Next, the flat upper lid 3 is placed on the flat lower lid 2. In this case, since the porous sheet 7 is formed with the concave portion 8 having a shape corresponding to the concave portion 4 of the flat upper lid 3, the distal end surface of the concave portion 8 is formed by the flat lower lid 2. Closely adhere to the inside. The upper and lower flat lids 2 and 3 are joined by appropriate means such as welding, brazing, and an adhesive.

FIGS. 2 and 3 show a longitudinal sectional side view and a schematic view of the container 1 thus constructed. As shown in FIGS. 1 and 2, a small-diameter pipe (nozzle) 9 communicating with the inside is attached to a predetermined location at the end of the container 1. A non-condensable gas such as air is exhausted from the inside of the container 1 through the nozzle 9, and a condensable working fluid such as water is sealed therein to form a heat pipe. Note that these deaeration and sealing operations may be performed according to a conventionally known method.

In the above-described flat plate heat pipe according to the present invention, the porous sheet 7 attached to the inside of the flat upper cover 3 functions as a wick and holds a liquid-phase working fluid. Therefore, for example, if the flat lower lid 2 is used as a heating section and a heating element such as a CPU (not shown) is attached thereto and the flat upper lid 3 is used as a heat radiating section, the working fluid is heated by the heat of the heating element. Then, the vapor flows and flows toward the flat upper cover 3 serving as a heat radiating portion, and radiates heat to the outside to condense. That is, the working fluid transports heat mainly as its latent heat. The condensed and liquefied working fluid is dripped toward the inner surface of the flat lower lid 2 and returns to the heat generating portion. At the same time, it is dispersed over the entire surface of the flat lower lid 2 by the capillary action of the wick.

Therefore, when the working fluid is not operating as a heat pipe, the working fluid is condensed and liquefied, so that the inside of the container 1 is at a vacuum pressure. Since the portion 4 is supported, deformation such as depression of the flat lids 2 and 3 is prevented. When the heat pipe is in operation, the pressure inside the container 1 increases, but since the concave portions 4 support the upper and lower flat lids 2 and 3, these lids 2 and 3 are supported. Is prevented from swelling outward.

In the above-described specific example, an example of a rectangular flat heat pipe has been described. However, the present invention is not limited to the above specific example, but may have any suitable shape such as a square shape or an elliptical shape. Can be applied to the flat plate type heat pipe. Further, in the present invention, instead of forming the porous layer by fixing the porous sheet, a structure functioning as a wick such as a narrow groove is formed on the inner surface of each lid, and this is combined with the frame member. This may constitute a heat pipe container. Further, the porous sheet, the porous layer or the wick may be provided on a part of the inner surface of the upper lid. In addition, the concave part
The shape is not limited to a truncated cone, but may be any shape that is concave, such as a cylinder or a prism.

[0024]

As described above, according to the first aspect of the present invention, a flat container can be formed by joining and integrating a flat upper lid and a flat lower lid. it can. In order to make this into a heat pipe, ordinary degassing and sealing of the working fluid may be performed. Then, the porous sheet formed on the inner surface of the flat upper lid functions as a wick. As described above, according to the first aspect of the present invention, it is possible to manufacture the container by laminating and fixing a plurality of parts, thereby improving the workability of the manufacture, and consequently producing a large number of inexpensive flat plate heat pipes. Will be possible.

According to the second aspect of the present invention, the first aspect is provided.
In addition to the effects of the invention, the concave portion formed in the flat upper lid can support the upper and lower portions of the hollow container as pillars. As a result, deformation of the container at the time of manufacturing, non-operation, or operation can be prevented. Also,
Since the concave portion is formed integrally with the flat upper lid, the container can be manufactured by fixing the flat upper and lower lids in the same manner as in the first aspect of the present invention. Workability is improved.

According to the third aspect of the present invention, in addition to the effects of the first and second aspects of the present invention, the concave portion is brought into contact with the flat lower cover, so that it can be manufactured, operated or operated. The deformation of the container at the time can be reliably prevented.

According to the fourth aspect of the present invention, in addition to the effects of the first to third aspects, the porous sheet further comprises:
The rigidity of the large-area upper and lower lids is increased by embossing and fixing them to the shape of the inner surface of the flat upper lid, and the deformation can be reliably prevented or suppressed, and at the same time, the upper and lower lids of the working fluid Can improve the reflux or dispersibility with respect to the inner surface, and can thereby improve the heat transport ability.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a flat heat pipe according to the present invention.

FIG. 2 is a vertical sectional side view taken along the line II-II in FIG.

FIG. 3 is an exploded schematic view showing a hollow container in an example of the flat plate heat pipe according to the present invention.

FIG. 4 is an enlarged vertical sectional side view showing an IV section in FIG. 2;

FIG. 5 is an enlarged longitudinal side view showing a V portion in FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Container, 2 ... Flat lower lid, 3 ... Flat upper lid
4 ... concave part, 5 ... porous sheet.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuji Saito 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Co., Ltd. (72) Inventor Tan Nuen 1-5-1, Kiba, Koto-ku, Tokyo Stock Company Inside Fujikura

Claims (4)

[Claims] 1. A flat heat pipe in which substantially only a condensable fluid is sealed in a flat hollow container, wherein the flat lower lid and a concave shape which is depressed toward the flat lower lid are provided. A flat container having an emboss wick, wherein the hollow container is formed by a flat upper cover having a concave portion, and a porous sheet is provided on an inner surface of the flat upper cover having the concave portion. heat pipe. 2. The method according to claim 1, wherein a plurality of the concave portions are provided at a substantially central position in a width direction of the flat upper cover and at predetermined intervals in a length direction of the flat upper cover. A flat heat pipe provided with the emboss wick according to claim 1. 3. The flat heat pipe provided with an emboss wick according to claim 1, wherein the concave portion is provided in contact with the flat lower lid. 4. The flat heat pipe provided with an emboss wick according to claim 1, wherein the porous sheet is embossed according to the shape of the inside of the flat upper body. .