JP3035773B2 - Heat pipe and this processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-dissipating heat pipe used for information electronic equipment and the like, and a method for processing 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. In order to meet this demand, thin-plate heat pipes have been used for heat distribution of the heat-generating components.

In order to make a heat pipe thin,
It is necessary to reduce the steam passage of the working fluid to near the limit of the required heat flow rate, to control the accuracy of the internal area by inserting a core during processing, and to minimize the thickness of the container material.

[0004]

However, in order to withstand the mechanical pressure from the outside to the container and the internal pressure due to the gas-liquid two-phase change even if these operations are performed, the liquid generated due to the starting characteristics of the heat pipe is required. Since pools are generated partially in the axial direction of the heat pipe and cause an increase in thermal resistance, there is naturally a limit to the reduction in thickness, and conventionally the thickness of the material is 1.
Only 5mm or more could be realized.

In view of the above problems, the present invention has a thickness of 1 mm.
It is an object of the present invention to provide a heat pipe capable of obtaining a good effect and a processing means for the heat pipe, even if

[0006]

In order to solve the above-mentioned problems, the present invention not only eliminates the necessity of a core which is usually taken in and out for each processing, but also optimizes the working fluid reflux of the heat pipe. This makes it possible to provide an extremely inexpensive heat pipe that is extremely thin, having a thickness of 1 mm or less, and that has excellent heat transport capability and thermal resistance characteristics.

[0007] More specifically, in the first aspect, a flat container and a concave wall having a space around the entire width and length of the inside of the container so that at least one side near the center is depressed are formed. And a wick is formed between the heat pipe and the opposite wall . According to claim 2, in a heat pipe used for electronic equipment, one end of the container is subjected to squeezing as a working fluid injection port, and the other end is sealed by pressing or welding, and at least one surface of the container is in an axial direction. Forming a concave wall of a dimension shorter than the length dimension of
When the concave wall and the opposing wall are in contact with each other, a loop-shaped heat pipe is formed by the concave wall and the inner wall of the container, and the injection port is a heat pipe that is sealed after injection of the working fluid. According to a third aspect of the present invention, there is provided a heat pipe according to the first or second aspect, wherein the working fluid amount is enclosed by 25% or more of the volume in the container space. According to a fourth aspect of the present invention, at least a part of the inside of the container is provided with a wick made of groove processing or mesh.
The heat pipe described in (1). In claim 5, at least a part between the recessed wall and the opposing wall is welded.
To a heat pipe according to claim 4. According to a sixth aspect of the present invention, there is provided a method of processing a heat pipe in which a round bar-shaped heat pipe is pressed into a flat shape or after the press processing, at least a portion near a substantially central portion on one side is concavely processed. In claim 7, the heat pipe is 50
The method for processing a heat pipe according to claim 5, wherein the temperature is maintained at a temperature of not less than ° C.

[0008]

FIG. 1 is an overall perspective view of a heat pipe according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the heat pipe taken along line AA in the direction of the arrow. 1 and 2, the main body
10, a cylindrical pipe is cut into a predetermined length, one end is drawn, and the other is sealed, and a container is provided between the two ends.
It is 12. The drawing part 11 is a working fluid inlet.
In the assembly process, the inlet 16 is sealed and the inside of the main body 10 is sealed. On the inner wall of the container 12, a wick made of a groove (hereinafter referred to as "groove wick 13") is provided.

Next, the container 12 and the groove wick 13 will be described in detail below. A wall recessed near the center of the interior of the container 12 having the groove wick 13 on the inner wall (hereinafter referred to as a “concave wall 29”) is in contact with the opposing wall 28, and the side of the contact wall is the axis of the heat pipe. Forming a directional wick. At this time, the container 12 has only one side near the center of the flat main body 10 recessed, and this cross-sectional view is as shown in FIG. In addition, since the concave wall 29 has a length less than the effective length of the container 12, a loop-shaped heat pipe is formed over the entire circumference of the container 12, and the influence of the capillary pressure limit and the scattering limit. It has a small structure.

More specifically, the main body 10 has a thickness
A tube made of oxygen-free copper or phosphorous deoxidized copper with a diameter of about 0.18 mm and an outer diameter of about 3 mm to 15 mm is cut to a length of about 180 mm, and a groove of about 0.12 mm in height is applied to this inner surface. The concave wall 28 is pressed in the direction indicated by the arrow in FIG. 4, but is formed with a length less than the effective length of the container 12 serving as the heat transfer portion of the main body 10. Also, the main body 10
Is drawn to a small diameter for injection of a working fluid to form a drawn portion 11. Further, the other end of the main body 10 is drawn or pressed, and then welded or brazed to be sealed as a sealing portion 14.
12Depressurize the inside, inject a predetermined amount of working fluid such as pure water, press-fit the inlet 16 and cut and weld unnecessary parts to complete the heat pipe for a time, then flatten it to the desired final shape And concave surface processing are performed simultaneously or in separate steps.

Here, when ordinary flat press working is performed, as shown in FIG. 8, both sides have a gentle curved surface and a concave is formed inside. This is more noticeable when the main body 10 is deformed into an L shape as shown in FIG.

However, in the present invention, the container 12
By forming only one side of the concave wall 29 into a shape, the opposite wall 28
Since the wall surface is flattened, no special process is required if the width of the heat pipe is not wide. For wide heat pipes, heat pipe at least 50 ° C
By heating and increasing the vapor pressure of the working fluid to perform processing, the desired shape can be easily obtained.

[0013] Further, by having the above-mentioned loop-shaped heat pipe structure, when the steam passage must be set to be extremely small, the working fluid amount is relatively increased to 25% or more of the container space volume, thereby enabling the operation. The generation of the pressure fluctuation oscillating flow of the vapor bubbles due to the nucleate boiling of the liquid is promoted, and heat transfer can be performed effectively.

Next, the operation of the heat pipe of the present invention will be described with reference to FIG. FIG. 3 is a view for modeling and explaining the operation when the flat thickness of the heat pipe of the first embodiment is set to be small. For the sake of explanation, the inner wall of the container 12 has grooves or grooves. No wick 13 such as mesh is provided. In FIG. 3, the space shown inside the container 12 shows a gas phase, and the horizontal line shows a liquid phase. By heating the heat receiving part, the working fluid becomes nucleate boiling and becomes a vapor bubble, and at the same time a pressure vibration wave is generated. The heat transport is performed by the phenomenon in which all the vapor bubbles that have taken away expand and contract and move to the radiator side.

As described above, since the heat transport by the slag flow is performed, it is dominated by the surface tension of the working fluid. However, there is no capillary pressure or scattering limit caused by the vapor flow pressure in a normal heat pipe, and the It is possible to make the narrow wall interval as thin as possible. In FIG. 3 which is the model diagram, the role when a wick 13 such as a group or a mesh is provided is unclear, but the wick 13 is installed when it is not necessary to narrow the interval between the narrow walls of the container 12 to the limit. And an auxiliary role of pumping mainly the hydraulic fluid reflux in the axial direction,
Responsible for heat transfer in the cross-sectional direction.

The direction and shape of the concave wall 29 in the first embodiment are not particularly limited, but may be other shapes such as a triangle, a circle, or a trapezoid, or both walls may be subjected to concave wall processing to form a heat receiving structure. It is easy to appropriately perform such as supplementing with another collector or the like.

Further, the groove wick 13 used in the embodiment of the present invention may be changed to a wick such as a mesh or a wire, and as described in the model of FIG. However, the wick is not necessary for the entire inner surface, and there are cases where it is better not to have the wick for thinning. This example is shown in FIGS. 5 and 6 as the second and third embodiments, respectively. In the second and third embodiments, portions other than the presence / absence of the groove wick 13 are the same as or equivalent to those in the first embodiment, and a description thereof will be omitted.

In order to protect the recessed mutual wall from the internal pressure that can be put under the high temperature operation of the heat pipe, the wall may be welded by spot welding or the like. The heat pipe is not limited to pure water, and a similar thin heat pipe can be obtained using a known material.

[0019]

As described in detail above, according to the present invention, a pipe having an outer shape selected by a required container width,
After optimally combining wicks selected according to the required container thickness and completing a normal round bar heat pipe,
It is to be post-processed into a flat shape as required by the customer, so that not only standardization of the heat pipe process and suppression of inventory items, but also flat heat pipes that require special flatness, such as softening of material due to welding heat etc. Hardness can also be recovered by age hardening of processing.

In addition, the core and the heat pipe need not be specially corrected to correct the dent deformation after completion of the heat pipe, and also a loop-shaped heat pipe exhibiting excellent characteristics of hydraulic fluid reflux can be obtained. In addition, it is possible to obtain a heat pipe and a heat pipe processing method that can be made as thin as possible.

In addition, since the deformation processing is performed after the heat pipe is completed, there are many excellent characteristics such as a reduction in individual characteristic variations.

[Brief description of the drawings]

FIG. 1 shows a perspective view of a heat pipe of the present invention.

FIG. 2 is a cross-sectional view of the AA cross section of FIG.

3 shows an axial sectional view of FIG. 1;

FIG. 4 shows a state before press working of FIG. 2;

FIG. 5 is a sectional view of a heat pipe according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a heat pipe according to a third embodiment of the present invention.

FIG. 7 shows a perspective view of an L-shaped heat pipe.

FIG. 8 is a cross-sectional view showing a case where a normal concave shape is added to a container.

[Explanation of symbols]

 In the drawings, the same reference numerals indicate the same or corresponding parts. DESCRIPTION OF SYMBOLS 10 Main body 11 Drawing part 12 Container 13 (groove) wick 14 Sealing part 16 Injection port 28 Concave wall 29 Opposing wall

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F28D 15/02 102 F28D 15/02 F28D 15/02 101 F28D 15/02 106

Claims (7)

(57) [Claims] 1. A flat container and a concave wall formed by recessing at least one side near a substantially central portion of the container so as to have a space around the entire width and length of the container. C
A heat pipe that has formed an ic . 2. A heat pipe used in an electronic device, wherein one end of a container is drawn by using one end of a working fluid as an inlet for working fluid, and the other end is sealed by pressing or welding. A concave wall having a dimension shorter than the length dimension is formed, and the concave wall and the opposing wall are in contact with each other to form a loop-shaped heat pipe with the concave wall and the inner wall of the container, and the injection port is provided after the hydraulic fluid is injected. A heat pipe that has been sealed. 3. The heat pipe according to claim 1, wherein the amount of the working fluid is enclosed by 25% or more of the volume in the container space. 4. The heat pipe according to claim 1, wherein a wick made of groove processing or mesh is provided on at least a part of the inside of the container. 5. The heat pipe according to claim 1, wherein at least a portion between the recessed wall and the opposing wall is welded. 6. A method of processing a heat pipe in which a round rod-shaped heat pipe is pressed into a flat shape or after the above-described press processing, at least the vicinity of a substantially central portion on one side is concavely processed. 7. The method according to claim 6, wherein the heat pipe is maintained at a temperature of 50 ° C. or higher.