JP2000031680A - Plate heat pipe and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] By providing a low-cost heat pipe excellent in heat transport capacity and heat resistance, it is extremely thin with a thickness of 1 mm or less by compensating for the drawbacks of conventional heat pipes with a laminated plate structure. I do. [Constitution] A non-crimped portion of a required pattern having a flat surface on one side and a trapezoidal cavity on a cross-section, and a container made of two pieces of laminated metal plates and a center of a main portion of the non-crimped portion. A plate-shaped heat pipe is characterized in that a wick is fixed in the vicinity and a working fluid is sealed in the trapezoidal cavity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat radiating device for electronic components used in electronic equipment, and more particularly to a thin and wide plate-shaped heat pipe for radiating electronic components in information electronic equipment, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Information electronic devices such as notebook PCs meet the demand for light weight and thinness, and with the integration of functions,
The heat generation density of electronic components such as U has become extremely high, and a thin and wide heat pipe has been required for heat distribution of these heat generation components.

Conventionally, a wide heat pipe is a plate-shaped heat pipe made by a so-called roll bonding method in which a container is made of a laminated plate having a non-pressed portion in a required pattern and then a hollow expansion portion is formed by fluid pressure. Has been proposed.

[0004]

However, in such a conventional plate-shaped heat pipe, the limit of thickness reduction is about 3 mm in order to stabilize required heat transport and stabilize the expansion process, and at the same time, the thickness of the heat pipe is reduced. The wick of the heat pipe of the structure is
Since it is composed only of the expansion section grooves of the plywood, it has a large thermal resistance and a small amount of heat transport per unit volume, and is unsuitable for a portable device whose installation direction is not fixed.

On the other hand, in order to make a normal heat pipe thin, the steam passage of the working fluid must be reduced to near the limit of the required heat flow rate, the precision of the internal area must be controlled during processing, and the container material must be controlled. It is necessary to make the thickness extremely small, but even with these controls, the width of a practical heat pipe is sufficient to withstand the external mechanical pressure on the container and the internal pressure caused by the gas-liquid two-phase change. It was at most about 10 mm at most, far from wide heat pipes.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a heat pipe having an extremely thin thickness of 1 mm or less and excellent heat transfer capability and heat resistance characteristics by compensating for the drawbacks of a conventional heat pipe having a laminated plate structure. The purpose is to provide it at low cost.

[0007]

In order to solve the above-mentioned problems, according to the present invention, a plate is formed by joining a first metal plate and a second metal plate, and the first metal plate and the second metal plate are connected to each other. The mating surface with the second metal plate has a crimped portion and a non-pressed portion, and at least one metal plate of the non-pressed portion is a trapezoidal cavity, and a flat wick is arranged in the trapezoidal cavity. A plate-shaped heat pipe having a heat pipe structure.

According to a second aspect of the present invention, there is provided a container which is flat on one side and has a non-pressed portion of a required pattern having a trapezoidal cavity in cross section on the other side. A wick is fixed near the center of the main part of the crimping portion, and a working fluid is sealed in the trapezoidal cavity.

[0009] The container may be made by a method of forming a hollow inflatable portion by fluid pressure after producing a laminated plate having a non-pressed portion, or after inserting a wick into the container,
The heat pipe may be fixed by pressing, the heat pipe may be formed in a loop shape, or the heat pipe portion may be constituted by a plurality of independent heat pipes. Further, the second metal plate may have a comb shape.

[0010] In this manufacturing method, a plate to be a laminated plate is formed by printing an anti-pressing agent on either one of the first metal plate and the second metal plate, and a fluid pressure is applied to the non-pressing portion. To form a semicylindrical cross-section hollow portion, a round wick is inserted and arranged in the semicylindrical cross-section hollow portion, and the entire plate is pressed to form the semicylindrical hollow portion into a trapezoidal hollow portion shape. The round wick is crushed into a flat wick, and the flat wick is fixed between the first metal plate and the second metal plate. The operation is performed by injecting a working fluid after depressurizing the inside through the remaining wick insertion port which is press-bonded by welding.

[0011]

FIG. 1 is a view showing a first embodiment of the present invention, and FIG. 2 is a sectional structural view of FIG. In FIGS. 1 and 2, a plate 1 serving also as a container is formed of two metal plates, a first metal plate 2 and a second metal plate 3 made of copper, aluminum, or the like. The second metal plate 3 has a crimp portion and a non-crimp portion of a required pattern such as
Is swelled in a trapezoidal shape, and a flat wick 5 made of a mesh, a braided wire, or the like is installed substantially in the center of the trapezoidal cavity 4 at a portion indicated by a dotted line in FIG. 2 and is fixed between the metal plates 3.

The trapezoidal cavity 4 is filled with a working fluid such as pure water or ammonia (not shown) in an amount of 10% to 50% of the volume of the cavity after the pressure is reduced. Forming a pipe.

Next, a method of assembling the plate-shaped heat pipe of the above embodiment will be described. 0.3mm thickness with different elongation and thickness
On one of the surfaces of the two metal plates 2 and 3 is printed ink such as colloidal graphite or the like which is an anti-pressing agent in a required pattern, and then a laminated plate is formed. Here, the places where the anti-pressing agent is printed are a “day character” portion and a wick insertion opening (not shown). Thereafter, by applying a fluid pressure to the non-compression-bonded portion, a well-known kamaboko-shaped cross-section hollow portion 6 is formed.

FIG. 3 is a cross-sectional view in which a round wick 7 obtained by rounding a mesh having a wire diameter of about 0.1 mm into an outer shape of 2 mm from an insertion opening corresponding to the number of wicks (not shown) is inserted.
In this state, since the outer thickness of the semicylindrical cavity 6 is about 4 mm, the round wick 7 can be easily inserted.

Next, the entire plate 1 is pressed to form a trapezoidal cavity 6 having a trapezoidal cavity 4 having a thickness of 1 mm as shown in FIG. 2, and a round wick 7 is crushed and flattened. Is fixed between the first metal plate 2 and the second metal plate 3, and at the same time, the wick insertion opening (not shown) is crushed except one place, and the first metal plate 2 is ultrasonically welded. And the second metal plate 3 are crimped.

Then, after depressurizing the inside from the remaining wick insertion port, a working fluid is injected, and the wick insertion port is sealed according to the above-described steps.

The operation of the heat pipe having such a structure as shown in the first embodiment is performed in spite of the narrow steam passage.
It has been confirmed by the present applicants in Japanese Patent Application No. 09-369414 that it exhibits excellent heat pipe characteristics with low thermal resistance and high maximum heat transport limit.

That is, when a part of the plate-shaped heat pipe is heated, the working fluid in the heating part takes away the latent heat of evaporation and evaporates, and the vapor flow passes through the trapezoidal space 4 to reduce the temperature of the plate. The return path of the condensed working fluid is mainly the flat wick 5 and a plurality of loop-shaped heat pipes are formed through the flat wick 5, so that the slag is formed. Even if a flow is generated, there is no capillary pressure or scattering limit due to the vapor flow pressure in a normal heat pipe, and it is possible to minimize the container narrow wall interval.

Next, a second embodiment and a third embodiment of the present invention will be described with reference to FIGS. The second embodiment shown in FIG. 4 forms three independent straight heat pipes, and the third embodiment shown in FIG. 5 forms a comb-shaped heat pipe and has a flat shape. The wick 5 is not inserted in the common part of the comb teeth. In the second and third embodiments, the configuration of the loop heat pipe described in the first embodiment is 3
Although the configuration of the loop heat pipe is limited, for example, only around the flat wick 5 of each of the individual heat pipes, the basic configuration and operation of the heat pipe are as follows.
The description is omitted because it is the same as the embodiment.

In the first to third embodiments, one of the two metal plates is a flat plate. However, depending on the purpose, both may be expanded. In, the container of the two laminated plate structure,
Although it is made by the roll bond method, at least one of the two metal plates is a plate that has been previously press-molded with a semicircular cross section and is bonded to another by ultrasonic welding or the like. can get.

The flat wick 5 can be selected as appropriate, such as a sintered metal or a glass fiber coated with metal, and the effect of the present invention is not limited.

[0022]

As described above in detail, according to the present invention, a plate composed of two metal plates having an outer shape selected according to a required container width and a wick selected according to a required container thickness are provided. By combining with the material, it is not necessary to insert and remove the core for each processing necessary for precision control which is indispensable for flat sheet processing, especially for thin sheet processing, and heating shaping to correct dent deformation after completion of heat pipe, etc. Since it is possible to obtain a loop-shaped heat pipe exhibiting excellent characteristics of working fluid reflux, it is possible to obtain a thin and wide plate-shaped heat pipe that can be made as thin as possible.

Further, since it is hardly deformed, there is little variation in individual characteristics, and it has a number of excellent characteristics such that it can be used by allowing bending after completion of the heat pipe.

[Brief description of the drawings]

FIG. 1 is a perspective view of a heat pipe according to a first embodiment of the present invention.

FIG. 2 shows a sectional structural view of FIG.

FIG. 3 shows a structural view during an assembling process of FIG. 2;

FIG. 4 shows a perspective view of a heat pipe according to a second embodiment.

FIG. 5 is a perspective view of a heat pipe according to a third embodiment.

[Explanation of symbols]

 In the drawings, the same reference numerals indicate the same or corresponding parts. Reference Signs List 1 plate 2 first metal plate 3 second metal plate 4 trapezoidal cavity 5 flat wick 6 semicylindrical cavity 7 round wick

Claims (8)

[Claims] A plate is formed by joining a first metal plate and a second metal plate, and a crimping portion and a non-crimping portion are formed on a mating surface between the first metal plate and the second metal plate. A plate-shaped heat pipe having at least one metal plate of the non-press-bonded portion as a trapezoidal cavity, a flat wick disposed in the trapezoidal cavity, and a heat pipe structure. 2. A container which is flat on one side and has a non-crimped portion of a required pattern having a trapezoidal cavity in cross section, and a container made of two pieces of laminated metal plates as a whole. A plate-shaped heat pipe wherein a wick is fixed near the center of the section, and a working fluid is sealed in the trapezoidal cavity. 3. The plate-shaped heat according to claim 1, wherein the container is formed by a method of forming a hollow inflatable portion by fluid pressure after forming a laminated plate having a non-pressed portion. pipe. 4. The plate-shaped heat pipe according to claim 1, wherein the wick is inserted into the container and then fixed by pressing. 5. The plate-shaped heat pipe according to claim 1, wherein the heat pipe is formed in a loop shape. 6. The plate-shaped heat pipe according to claim 1, wherein the heat pipe portion comprises a plurality of independent heat pipes. 7. The plate-shaped heat pipe according to claim 1, wherein the second metal plate has a comb shape. 8. A plate to be a laminated plate by printing an anti-pressing agent on one of the surfaces of the first metal plate and the second metal plate, and applying a fluid pressure to a non-pressing portion to form a plate. A round wick is inserted and arranged in the hollow section, and the round wick is crushed by pressing the entire plate and making the hollow section into a trapezoidal shape. It becomes a flat wick, the flat wick is fixed between the first metal plate and the second metal plate, and at the same time, the insertion port into which the wick is inserted is crushed except for one place, and crimped by welding, A method for manufacturing a plate-shaped heat pipe, wherein a working fluid is injected after depressurizing the inside through the remaining wick insertion port.