JP6799503B2 - Heat pipe and its manufacturing method - Google Patents

Description

The present invention relates to a heat pipe and a method for manufacturing the same.

A heat pipe is known as a device for cooling heat-generating components such as a CPU (Central Processing Unit) mounted on an electronic device. A heat pipe is a device that transports heat by utilizing the phase change of a working fluid.

As an example, a heat pipe is proposed in which plates having meandering grooves on one side are arranged in a grid pattern at a crossing angle of 90 degrees, and a working fluid is sealed in a tunnel of meandering grooves. This heat pipe has a structure in which the steam pipe and the liquid pipe are not separated (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2001-165582

However, in the above heat pipe, the vapor diffusion from the evaporation part and the return of the condensed working fluid pass through the same tunnel. Therefore, the working fluid evaporates near the heat generating portion and spreads along the tunnel of the groove, but the presence of the working fluid in the tunnel hinders the spread of steam. Also, when the working fluid that has been cooled, condensed and liquefied after the steam spreads returns to the evaporation section, it collides with the steam from the evaporation section. Since evaporation and condensation do not operate as a cycle in this way, heat dissipation is not good.

The present invention has been made in view of the above points, and an object of the present invention is to provide a heat pipe having improved heat dissipation.

The heat pipe is a heat pipe including a steam layer for moving vapor vaporized by the working fluid and a liquid layer for moving the working fluid liquefied by the steam, and the liquid layer has one surface. A plurality of first bottomed holes recessed from the side and arranged apart from each other, a plurality of second bottomed holes recessed from the other surface side, the first bottomed hole and the second bottomed hole. A first pore formed by partially communicating with the bottomed hole and a second pore formed by partially communicating with the side surface of the adjacent second bottomed hole. The vapor layer is composed of a first metal layer provided, and the steam layer is a second metal layer formed in a frame shape on one surface of the first metal layer so as to expose the plurality of first bottomed holes. It is a requirement that it consists of.

According to the disclosed technique, it is possible to provide a heat pipe having improved heat dissipation.

It is a figure which illustrates the heat pipe which concerns on 1st Embodiment. It is a figure (the 1) explaining the function of each part of the heat pipe which concerns on 1st Embodiment. It is a figure (the 2) explaining the function of each part of the heat pipe which concerns on 1st Embodiment. It is a figure which illustrates the manufacturing process of the heat pipe which concerns on 1st Embodiment. It is a figure which illustrates the heat pipe which concerns on the modification 1 of the 1st Embodiment. It is a figure which illustrates the heat pipe which concerns on the modification 2 of the 1st Embodiment. It is a figure which illustrates the heat pipe which concerns on the modification 3 of the 1st Embodiment. It is a figure which illustrates the heat pipe which concerns on the modification 4 of the 1st Embodiment. It is a figure which illustrates the heat pipe which concerns on 2nd Embodiment. It is a figure which illustrates the manufacturing process of the heat pipe which concerns on 2nd Embodiment. It is a figure which illustrates the heat pipe which concerns on the modification 1 of the 2nd Embodiment.

Hereinafter, modes for carrying out the invention will be described with reference to the drawings. In each drawing, the same components may be designated by the same reference numerals and duplicate description may be omitted.

<First Embodiment>
[Structure of heat pipe according to the first embodiment]
First, the structure of the heat pipe according to the first embodiment will be described. FIG. 1 is a diagram illustrating a heat pipe according to the first embodiment, FIG. 1 (b) is a plan view, and FIG. 1 (a) is a cross-sectional view taken along the line AA of FIG. 1 (b). Is.

With reference to FIG. 1, the heat pipe 1 is an omnidirectional heat pipe having a structure in which four layers of metal layers 11 to 14 are laminated. The metal layers 11 to 14 are made of, for example, copper having excellent thermal conductivity, and are directly bonded to each other by solid phase bonding or the like. The thickness of each of the metal layers 11 to 14 can be, for example, about 50 μm to 200 μm. The material of the metal layers 11 to 14 is not limited to copper, and may be formed from a material having high thermal conductivity such as stainless steel, aluminum, and magnesium alloy. Here, the planar shape of the heat pipe 1 (the shape seen from the normal direction of the upper surface 14a of the metal layer 14) is rectangular as an example.

In FIG. 1, the stacking direction (thickness direction) of the metal layers 11 to 14 is the Z direction, the direction parallel to one side of the upper surface 14a of the metal layer 14 is the X direction, and the X direction in the upper surface 14a of the metal layer 14. The orthogonal direction is the Y direction (the same applies to the following figures). Further, in the present embodiment, for convenience, the metal layer 14 side of the heat pipe 1 is the upper side or one side, and the metal layer 11 side is the lower side or the other side. Further, the surface of each part on the metal layer 14 side is defined as the upper surface or one surface, and the surface on the metal layer 11 side is defined as the lower surface or the other surface.

In the heat pipe 1, the metal layer 11 of the first layer (the other outermost layer) and the metal layer 14 of the fourth layer (one outermost layer) are solid metal layers in which no holes or grooves are formed.

The metal layer 12 is laminated on the upper surface of the metal layer 11. The second metal layer 12 has a bottomed hole 121 recessed from the metal layer 13 side (upper surface side of the metal layer 12) toward a substantially central portion in the Z direction, and a metal layer 11 side (lower surface side of the metal layer 12). ) To the substantially central portion in the Z direction, and a plurality of bottomed holes 122 are arranged. Further, a pore 123 in which the bottomed hole 121 and the bottomed hole 122 are partially communicated with each other is arranged.

The metal layer 12 has a through hole 12x penetrating in the Z direction, which is composed of a bottomed hole 121, a bottomed hole 122, and a pore 123.

The plurality of bottomed holes 121 are arranged in a matrix. The plurality of bottomed holes 121 include, for example, rows arranged at predetermined intervals in the X direction and columns arranged at predetermined intervals in the Y direction. However, the rows do not necessarily have to be along the X direction, and the columns do not necessarily have to be along the Y direction.

Further, the rows and columns do not necessarily have to be orthogonal to each other. For example, the planar shape of the region where the columns are provided diagonally with respect to the rows and a plurality of bottomed holes 121 are arranged is a parallel quadrilateral shape as a whole. There may be. Further, the number of bottomed holes 121 included in each row and each column does not have to be the same. For example, the planar shape of the region where the plurality of bottomed holes 121 are arranged may be trapezoidal as a whole. .. Further, the plurality of bottomed holes 121 may be arranged in a staggered pattern.

One bottomed hole 122 is provided corresponding to each bottomed hole 121. The corresponding bottomed holes 121 and the bottomed holes 122 are arranged so as to overlap each other in a plan view, and the bottom surfaces partially communicate with each other to form the pores 123. That is, the plurality of bottomed holes 122 are arranged in a matrix corresponding to the plurality of bottomed holes 121, and the bottom surfaces of the bottomed holes 121 and the bottomed holes 122 that overlap in a plan view are in contact with each other. It communicates in the Z direction. However, the bottomed holes 121 and the bottomed holes 122 do not necessarily have to be arranged so as to completely overlap each other in a plan view as long as the bottom surfaces are arranged so as to communicate with each other through the pores 123. Absent.

The bottomed holes 121 are arranged apart from each other. That is, the bottomed holes 121 adjacent to each other in the X direction and the Y direction do not communicate with each other. On the other hand, the bottomed holes 122 adjacent to each other in the X direction and the Y direction are partially communicated with each other in the X direction and the Y direction through the pores 125. That is, all the bottomed holes 122 arranged in a matrix communicate with each other through the pores 125.

The area of the portion of the bottomed hole 121 that opens on the upper surface side of the metal layer 12 is smaller than the area of the portion of the bottomed hole 122 that opens on the lower surface side of the metal layer 12. The bottomed hole 121 is formed, for example, substantially hemispherically, and has a circular planar shape. In this case, the diameter φ ₁ of the portion of the bottomed hole 121 that opens to the metal layer 13 side can be, for example, about 25 μm.

The bottomed hole 122 is formed, for example, substantially hemispherically, and has a circular planar shape. In this case, the diameter phi ₂ of the portion opening to the lower surface of the metal layer 12 of the bottomed hole 122 is larger than the diameter phi ₁ of the portion opening to the upper surface side of the metal layer 12 of the bottomed hole 121, for example, 50 [mu] m Can be a degree.

The position where the bottomed hole 121 and the bottomed hole 122 communicate with each other (the position of the pore 123) is closer to the upper surface side of the metal layer 12 than the center in the thickness direction of the metal layer 12, for example, D ₁ : D _2. Can be about 3: 7. Diameter phi ₃ of the pores 123 is less than the diameter phi ₂ of the diameter phi ₁ and the bottomed holes 122 of the bottomed hole 121, for example, may be about 15 [mu] m.

However, the planar shape of the bottomed holes 121 and 122 is not limited to a circle, and may be any shape such as an ellipse or a polygon. Further, the bottomed hole 121 is not limited to a substantially hemispherical shape, and may have an arbitrary tapered shape in which the inner wall widens from the pore 123 side toward the upper surface side of the metal layer 12. Similarly, the bottomed hole 122 is not limited to a substantially hemispherical shape, and may have an arbitrary tapered shape in which the inner wall widens from the pore 123 side toward the lower surface side of the metal layer 12.

The width W _{1 in} the X direction, the width W _{2 in the} Y direction, and the height H ₁ in the Z direction of the pore 125 are each smaller than the diameter φ _{2 of the} bottomed hole 122. The width W ₁ of the pores 125 in the X direction can be, for example, about 20 μm. The width W ₂ of the pores 125 in the Y direction can be, for example, about 20 μm. The height H ₁ of the pores 125 in the Z direction can be, for example, about 10 μm.

The metal layer 13 is laminated on the upper surface of the metal layer 12. The third metal layer 13 has through holes 13x that expose the through holes 12x arranged in a matrix, and is formed in a frame shape. The metal layer 14 is laminated on the metal layer 13 so as to cover the frame portion formed by the metal layer 13.

FIG. 2 is a diagram (No. 1) for explaining the functions of each part of the heat pipe according to the first embodiment, and shows a cross section corresponding to FIG. 1 (a).

As shown in FIG. 2, in the heat pipe 1, the metal layer 11 and the metal layer 14 are layers that serve as outer walls. Further, in the heat pipe 1, the metal layer 13 formed in a frame shape becomes a steam layer. Specifically, the metal layer 13 (steam layer) has a gas phase portion 21 surrounded by the upper surface of the metal layer 12 and the lower surface of the metal layer 14 in the through hole 13x of the metal layer 13. The gas phase portion 21 is a region where the vaporized steam Cv of the working fluid C is moved from the high temperature side to the low temperature side.

Further, in the heat pipe 1, the metal layer 12 becomes a liquid layer. Specifically, the metal layer 12 (liquid layer) has a liquid flow path portion 22 and a ventilation portion 23. The liquid flow path portion 22 is composed of a bottomed hole 122 that communicates in the X direction and the Y direction in the metal layer 12. The liquid flow path portion 22 (bottomed hole 122) is a region for moving the working fluid C liquefied on the low temperature side to the high temperature side.

Further, the ventilation portion 23 is composed of the bottomed holes 121 and the pores 123 that communicate with the bottomed holes 122 in the metal layer 12. The ventilation portion 23 is a region that partitions the gas phase portion 21 and the liquid flow path portion 22 and moves the working fluid C generated in the gas phase portion 21 to the liquid flow path portion 22.

The liquid flow path portion 22 is filled with the working fluid C in the initial state (a state in which the heat pipe 1 is not in contact with the heat generating component). The type of the working fluid C is not particularly limited, but it is preferable to use a fluid having a high vapor pressure and a large latent heat of vaporization in order to efficiently cool the heat-generating component by the latent heat of vaporization. Examples of such fluids include ammonia, water, chlorofluorocarbons, alcohols, and acetone.

FIG. 3 is a diagram (No. 2) for explaining the functions of each part of the heat pipe according to the first embodiment, FIG. 3 (b) is a plan view, and FIG. 3 (a) is FIG. 3 (b). It is sectional drawing which follows the line BB.

As shown in FIG. 3, in the heat pipe 1, through holes 12x (bottomed holes 121 and 122, pores 123) are evenly arranged when viewed from the normal direction of the upper surface 14a of the metal layer 14. Therefore, a heat generating component such as a semiconductor device can be arranged at an arbitrary position on the outer surface of the metal layer 11, and the position where the heat generating component is arranged becomes the heat generating portion. In FIG. 3, as an example, the lower left of the metal layer 11 is a heat generating portion H (evaporation portion).

In FIG. 3, when the temperatures of the metal layers 11 and 12 near the heat generating portion H rise, the working fluid C in the liquid flow path portion 22 near the heat generating portion H is vaporized (evaporated) to generate vapor Cv. The generated steam Cv moves to the gas phase portion 21 via the ventilation portion 23 and spreads over the entire gas phase portion 21. The portion away from the heat generating portion H becomes the condensing portion G, and the vapor Cv is liquefied in the condensing portion G.

As a result, the heat generated in the heat generating portion H moves to the condensing portion G and is dissipated. The working fluid C liquefied in the condensing portion G is sucked into the liquid flow path portion 22 through the aeration portion 23 by the capillary force of the pores 123. The working fluid C sucked into the liquid flow path portion 22 moves through the liquid flow path portion 22 to a place where the working fluid C is insufficient, that is, a heat generating portion H, due to the capillary force of the pores 125. After that, by repeating the evaporation and condensation cycles in the same manner, the temperature rise of the heat generating portion H is suppressed.

[Method for manufacturing a heat pipe according to the first embodiment]
Next, the method for manufacturing the heat pipe according to the first embodiment will be described. FIG. 4 is a diagram illustrating a heat pipe manufacturing process according to the first embodiment, and shows a cross section corresponding to FIG. 1 (a).

First, in the step shown in FIG. 4A, the metal sheet 120 is prepared, the resist layer 310 having the opening 310x is formed on the upper surface of the metal sheet 120, and the opening 320x is provided on the lower surface of the metal sheet 120. The resist layer 320 is formed. The opening 310x is formed so as to expose the upper surface of the metal sheet 120 at a position corresponding to the bottomed hole 121 shown in FIG. 1 (b). Further, the opening 320x is formed so as to expose the lower surface of the metal sheet 120 at a position corresponding to the bottomed hole 122 shown in FIG. 1 (b).

The metal sheet 120 is a member that finally becomes the metal layer 12, and can be formed of, for example, copper, stainless steel, aluminum, magnesium alloy, or the like. The thickness of the metal sheet 120 can be, for example, about 50 μm to 200 μm. As the resist layers 310 and 320, for example, a photosensitive dry film resist or the like can be used. The openings 310x and 320x can be formed, for example, by exposing and developing the resist layers 310x and 320.

Next, in the step shown in FIG. 4B, the metal sheet 120 exposed in the opening 310x is half-etched from the upper surface side of the metal sheet 120, and the metal sheet 120 exposed in the opening 320x is half-etched. Half-etch from the bottom surface side of. As a result, the bottomed hole 121 is formed on the upper surface side of the metal sheet 120, and the bottomed hole 122 is formed on the lower surface side. Further, the bottom surfaces of the bottomed hole 121 and the bottomed hole 122 are partially communicated with each other in the Z direction to form a pore 123, and a through hole 12x composed of the bottomed hole 121, the bottomed hole 122, and the pore 123 is formed. Will be done. Further, in the bottomed holes 122 adjacent to each other in the X direction and the Y direction, the side surfaces thereof partially communicate with each other in the X direction and the Y direction, and pores 125 are formed. For half-etching of the metal sheet 120, for example, a ferric chloride solution can be used. After that, the resist layers 310 and 320 are peeled off with a stripping solution to complete the metal layer 12 in which the through holes 12x are arranged in a matrix.

Next, in the step shown in FIG. 4C, a frame-shaped metal layer 13 having a through hole 13x is formed. The metal layer 13 can be formed by preparing a metal sheet and removing unnecessary portions of the metal sheet by etching. Alternatively, the metal layer 13 may be formed by preparing a metal sheet and removing unnecessary portions of the metal sheet by press working or laser processing.

Next, in the step shown in FIG. 4D, solid metal layers 11 and 14 having no holes or grooves are prepared. Then, the metal layers 11, 12, 13, and 14 are sequentially laminated, and solid phase bonding is performed by pressurization and heating. As a result, the adjacent metal layers are directly joined to each other, and the heat pipe 1 having the gas phase portion 21, the liquid flow path portion 22, and the ventilation portion 23 is completed. Then, after exhausting the inside of the liquid flow path portion 22 using a vacuum pump or the like, the working fluid C is injected into the liquid flow path portion 22 from an injection port (not shown), and then the injection port is sealed.

Here, the solid-phase bonding is a method in which objects to be bonded are heated and softened in a solid-phase (solid) state without being melted, and further pressurized to give plastic deformation for bonding. It is preferable that all the materials of the metal layers 11 to 14 are the same so that the adjacent metal layers can be satisfactorily bonded by solid phase bonding.

Thus, the heat pipe 1, and the liquid channel 22 through which the gas phase 21 and the working fluid through the gas-steam is divided. Therefore, the diffusion of the vapor Cv from the heat generating portion H (evaporation portion) side and the return of the working fluid C condensed on the condensing portion G side form separate layers and do not collide with each other. As a result, evaporation and condensation operate as a cycle, and heat dissipation can be improved.

Further, in the heat pipe 1, through holes 12x (bottomed holes 121 and 122, pores 123) are evenly arranged when viewed from the normal direction of the upper surface 14a of the metal layer 14. Therefore, there is no distinction between the heat generating portion H (evaporation portion) and the condensing portion G, and a heat generating component such as a semiconductor device can be arranged at an arbitrary position on the outer surface of the metal layer 11 to form the heat generating portion H. Then, the vapor Cv evaporated in the vicinity of the heat generating portion H spreads in all directions, and the portion having a low temperature becomes the condensing portion G to condense the steam. With such a structure, it is possible to realize a heat pipe having uniform heat diffusion performance in all directions and having no attitude dependence.

Further, in the heat pipe 1, a liquid flow path portion 22 and a ventilation portion 23 are formed in one metal layer. Therefore, the heat pipe 1 can be made thinner.

<Modification 1 of the first embodiment>
In the first modification of the first embodiment, an example in which a support column is provided is shown. In the first modification of the first embodiment, the description of the same components as those of the above-described embodiment may be omitted.

5A and 5B are views illustrating the heat pipe according to the first modification of the first embodiment, FIG. 5B is a plan view, FIG. 5A is a line AA of FIG. 5B. It is a cross-sectional view along.

With reference to FIG. 5, the heat pipe 1A is provided with a support column 15 inside a metal layer 13 formed in a frame shape. In the example of FIG. 5, four columns 15 are provided, but the columns 15 may be one to three or five or more.

By providing the columns 15 inside the metal layer 13 formed in the frame shape in this way, when the heat pipe 1A is manufactured, the metal layers 11, 12, 13, and 14 are manufactured in the step of FIG. 4 (d). It is possible to prevent the metal layer 14 from being crushed when the metal layers 14 are sequentially laminated and pressurized. Further, when the heat pipe 1A is operating, it is possible to prevent the metal layer 14 from being deformed and the gas phase portion 21 from being crushed.

<Modification 2 of the first embodiment>
In the second modification of the first embodiment, an example is shown in which a plurality of bottomed holes are provided on the upper surface side of the metal layer 12 with respect to one bottomed hole 122. In the second modification of the first embodiment, the description of the same components as those of the above-described embodiment may be omitted.

6A and 6B are views illustrating the heat pipe according to the second modification of the first embodiment, FIG. 6B is a partial plan view, and FIG. 6A is a CC of FIG. 6B. It is a partial sectional view along the line.

In the heat pipe 1B shown in FIG. 6, the second metal layer 12 has bottomed holes 121a and 121b recessed from the upper surface side of the metal layer 12 toward the substantially central portion in the Z direction, and the lower surface side of the metal layer 12. A bottomed hole 122 is formed that is recessed toward a substantially central portion in the Z direction. Further, pores 123a and 123b in which the bottomed holes 121a and 121b and the bottomed holes 122 partially communicate with each other are arranged.

The metal layer 12 has a through hole 12y penetrating in the Z direction, which is composed of bottomed holes 121a and 121b, bottomed holes 122, and pores 123a and 123b.

That is, in each through hole 12y, bottomed holes 121a and 121b are provided for one bottomed hole 122. The corresponding bottomed holes 121a and 121b and the bottomed holes 122 are arranged so as to overlap each other in a plan view. Then, the bottom holes 121a and the bottom surfaces of the bottom holes 122 are partially communicated with each other to form the pores 123a. Further, the bottom holes 121b and the bottom surfaces of the bottom holes 122 are partially communicated with each other to form pores 123b.

The bottomed holes 121a and the bottomed holes 121b that are adjacent to each other in the X direction are arranged apart from each other. Further, the bottomed holes 121a adjacent to each other in the Y direction and the bottomed holes 121b adjacent to each other in the Y direction are arranged apart from each other.

The area of the portion of the bottomed holes 121a and 121b that opens on the upper surface side of the metal layer 12 is smaller than the area of the portion of the bottomed hole 122 that opens on the lower surface side of the metal layer 12. The bottomed holes 121a and 121b are formed in a substantially hemispherical shape, for example, and have a circular planar shape. The positions where the bottomed holes 121a and 121b and the bottomed holes 122 communicate with each other (positions of the pores 123a and 123b) are on the upper surface side of the metal layer 12 rather than the center in the thickness direction of the metal layer 12.

However, the planar shape of the bottomed holes 121a and 121b is not limited to a circle, and may be any shape such as an ellipse or a polygon. Further, the bottomed holes 121a and 121b are not limited to a substantially hemispherical shape, and may have an arbitrary tapered shape in which the inner wall widens from the pores 123a and 123b side toward the upper surface side of the metal layer 12.

In this way, in each through hole 12y, two bottomed holes 121a and 121b may be provided on the upper surface side of the metal layer 12 with respect to one bottomed hole 122. In this case, since the sizes of the pores 123a and 123b can be made smaller than the size of the pores 123 of the first embodiment, the capillary force when sucking the working fluid C from the gas phase portion 21 into the liquid flow path portion 22. Can be increased.

It should be noted that three or more bottomed holes may be provided on the upper surface side of the metal layer 12 with respect to one bottomed hole 122. Further, a plurality of bottomed holes provided on the upper surface side of the metal layer 12 with respect to one bottomed hole 122 may have different sizes (for example, different diameters).

<Modification 3 of the first embodiment>
Modification 3 of the first embodiment shows an example of changing the density of bottomed holes. In the third modification of the first embodiment, the description of the same components as those of the above-described embodiment may be omitted.

FIG. 7 is a view illustrating the heat pipe according to the modified example 3 of the first embodiment, and is a plan view corresponding to FIG. 1 (b). However, in FIG. 7, only the bottomed hole 121 provided on the upper surface side of the metal layer 12 with respect to the bottomed hole 122 in the metal layer 12 is shown, and the bottomed hole 122 and the pore 123 are not shown. ing.

In the heat pipe 1C shown in FIG. 7, the high-density region Hd in which the bottomed holes 121 are arranged at high density and the low-density region Ld in which the bottomed holes 121 are arranged at low density alternate in the X direction and the Y direction. Is located in. In the high-density region Hd, for example, a plurality of bottomed holes 121 can be provided for one bottomed hole 122.

Like the heat pipe 1C, the density of the bottomed holes 121 does not necessarily have to be uniform, and a high-density region Hd and a low-density region Ld may be provided. In this case, the effect of improving the heat diffusion efficiency from the heat generating portion can be expected. Further, the effect of improving the vaporization efficiency of the working fluid and the efficiency of returning the liquefied working fluid to the liquid layer can be expected.

The regions having different densities are not limited to two types, and three or more regions having different densities may be included.

<Modification 4 of the first embodiment>
In the modified example 4 of the first embodiment, an example of changing the size of the bottomed hole is shown. In the modified example 4 of the first embodiment, the description of the same component as that of the above-described embodiment may be omitted.

FIG. 8 is a view illustrating the heat pipe according to the modified example 4 of the first embodiment, and is a plan view corresponding to FIG. 1 (b). However, in FIG. 8, only the bottomed holes 121c and 121d provided on the metal layer 13 side with respect to the bottomed holes 122 in the metal layer 12 are shown, and the bottomed holes 122 and the pores 123 are not shown. ing.

In the heat pipe 1D shown in FIG. 8, the area of the portion opened on the upper surface side of the metal layer 12 is large (for example, a large diameter) bottomed hole 121c, and the area of the portion opened on the upper surface side of the metal layer 12 is small. Bottomed holes 121d (for example, with a small diameter) are arranged alternately in the X direction and the Y direction. The bottomed holes 121c and 121d can be formed in a substantially hemispherical shape, for example, like the bottomed holes 121.

Like the heat pipe 1D, the area of the opening portion of each bottomed hole opened on the upper surface side of the metal layer 12 does not necessarily have to be the same, and the opening portion is opened with the bottomed hole 121c having a large area of the opening portion. It may have a bottomed hole 121d having a small portion area. In this case, the effect of improving the vaporization efficiency of the working fluid and the efficiency of returning the liquefied working fluid to the liquid layer can be expected.

The area of each bottomed hole opened on the metal layer 13 side is not limited to two types, and may be three or more types.

<Second Embodiment>
In the second embodiment, an example of further thinning the heat pipe is shown. In the second embodiment, the description of the same components as those in the above-described embodiment may be omitted.

[Structure of heat pipe according to the second embodiment]
First, the structure of the heat pipe according to the second embodiment will be described. 9A and 9B are views illustrating the heat pipe according to the second embodiment, FIG. 9B is a plan view, and FIG. 9A is a sectional view taken along the line AA of FIG. 9B. Is.

With reference to FIG. 9, the heat pipe 2 differs from the heat pipe 1 (see FIG. 1) in that the metal layers 13 and 14 are replaced with the one-layer metal layer 25, and the other points are the heat pipe 1 and the heat pipe 1. The same is true. That is, the heat pipe 2 is an omnidirectional heat pipe having a structure in which three layers of metal layers 11, 12, and 25 are laminated. The metal layers 11, 12, and 25 are made of, for example, copper, stainless steel, aluminum, magnesium alloy, etc., and are directly bonded to each other by solid phase bonding or the like.

The metal layer 25 includes a rectangular flat plate portion 251 having an upper surface 25a and a lower surface 25b, and a side wall portion 252 protruding from the outer peripheral portion of the lower surface 25b of the flat plate portion 251 toward the metal layer 12. The metal layer 25 has a concave shape in which the flat plate portion 251 and the side wall portion 252 are integrally formed. The side wall portion 252 has an opening 25x that exposes the through holes 12x arranged in a matrix, and is formed in a frame shape on the outer peripheral portion of the lower surface 25b of the flat plate portion 251. The lower surface of the side wall portion 252 of the metal layer 25 is directly joined to the outer peripheral portion of the upper surface of the metal layer 12.

The total thickness T ₁ of the metal layer 25 can be, for example, about 50 μm to 200 μm. The total thickness T ₁ of the metal layer 25 may be, for example, the same as the thickness of the metal layers 11 and 12. The thickness T ₂ of the side wall portion 252 of the metal layer 25 can be, for example, about half of the thickness T ₁ .

The side wall portion 252 of the metal layer 25 becomes a vapor layer, and has a gas phase portion 21 (see FIG. 2) surrounded by the upper surface of the metal layer 12 and the lower surface 25b of the metal layer 25 in the opening 25x of the side wall portion 252. ing. The gas phase portion 21 is a region where the vaporized steam Cv of the working fluid C is moved from the high temperature side to the low temperature side.

[Method for manufacturing a heat pipe according to the second embodiment]
Next, a method for manufacturing the heat pipe according to the second embodiment will be described. FIG. 10 is a diagram illustrating a heat pipe manufacturing process according to the second embodiment, and shows a cross section corresponding to FIG. 9A.

First, the steps of FIGS. 4 (a) and 4 (b) of the first embodiment are executed to prepare the metal layer 12.

Next, in the step shown in FIG. 10A, the metal sheet 250 is prepared, a solid resist layer 330 is formed on the entire upper surface of the metal sheet 250, and a rectangular opening 340x is formed on the lower surface of the metal sheet 250. A frame-shaped resist layer 340 is formed. The resist layer 340 is formed so as to cover the region where the side wall portion 252 is to be formed.

The metal sheet 250 is a member that finally becomes the metal layer 25, and can be formed of, for example, copper, stainless steel, aluminum, magnesium alloy, or the like. The thickness of the metal sheet 250 can be, for example, about 50 μm to 200 μm. As the resist layers 330 and 340, for example, a photosensitive dry film resist or the like can be used. The opening 340x can be formed, for example, by exposing and developing a resist layer 340.

Next, in the step shown in FIG. 10B, the metal sheet 250 exposed in the opening 340x is half-etched from the lower surface side of the metal sheet 250 to form a bottomed opening 25x on the center side, and the metal sheet 250 is formed. A side wall portion 252 that surrounds the opening 25x is formed on the outer peripheral side. For half-etching of the metal sheet 250, for example, a ferric chloride solution can be used. After that, the resist layers 330 and 340 are peeled off with a peeling liquid to form a metal layer 25 having a frame-shaped side wall portion 252 surrounding the opening 25x on the outer peripheral portion of the lower surface 25b of the flat plate portion 251.

In FIG. 10A, a solid resist layer 330 is formed on the entire lower surface of the metal sheet 250, and a frame-shaped resist layer 340 having a rectangular opening 340x is formed on the upper surface of the metal sheet 250. You may. In this case, in FIG. 10B, the metal sheet 250 exposed in the opening 340x is half-etched from the upper surface side of the metal sheet 250 to form the opening 25x.

Next, a solid metal layer 11 having no holes or grooves is prepared, and the metal layers 11, 12, and 25 are sequentially laminated in the same manner as in the step of FIG. 4D, and pressurized and heated. Solid phase bonding is performed by. As a result, the adjacent metal layers are directly joined to each other, and the heat pipe 2 provided with the gas phase portion 21, the liquid flow path portion 22, and the ventilation portion 23 is completed. Then, after exhausting the inside of the liquid flow path portion 22 using a vacuum pump or the like, the working fluid C is injected into the liquid flow path portion 22 from an injection port (not shown), and then the injection port is sealed. It is preferable that all the materials of the metal layers 11, 12, and 25 are the same so that the adjacent metal layers can be satisfactorily bonded by solid phase bonding.

In this way, the metal layers 13 and 14 in the heat pipe 1 may be replaced with the one metal layer 25 to form the heat pipe 2. In the heat pipe 2, since the bottomed hole and the opening are formed by half etching without using bending or molding, it is easy to reduce the thickness. In the heat pipe 2, for example, if the metal layers 11, 12, and 25 are all formed to have a thickness of 50 μm, a thin heat pipe having a total thickness of 150 μm can be realized. Other effects are as shown in the first embodiment.

<Modification 1 of the second embodiment>
In the first modification of the second embodiment, an example in which a support column is provided is shown. In the first modification of the second embodiment, the description of the same components as those of the above-described embodiment may be omitted.

11A and 11B are views illustrating the heat pipe according to the first modification of the second embodiment, FIG. 11B is a plan view, and FIG. 11A is a line AA of FIG. 11B. It is a cross-sectional view along.

Referring to FIG. 11, the heat pipe 2A is different from the heat pipe 2 (see FIG. 9) in that the metal layer 25 is replaced with the metal layer 25A, and is the same as the heat pipe 2 in other points. That is, the heat pipe 2A is an omnidirectional heat pipe having a structure in which three layers of metal layers 11, 12, and 25A are laminated. The metal layers 11, 12, and 25A are made of, for example, copper, stainless steel, aluminum, magnesium alloy, etc., and are directly bonded to each other by solid phase bonding or the like.

The metal layer 25A is provided inside a rectangular flat plate portion 251 having an upper surface 25a and a lower surface 25b, a side wall portion 252 protruding from the outer peripheral portion of the lower surface 25b of the flat plate portion 251 toward the metal layer 12, and the side wall portion 252. It is equipped with a support column 253. The flat plate portion 251 and the side wall portion 252 and the support column 253 are integrally formed. The side wall portion 252 has an opening 25x that exposes the through holes 12x arranged in a matrix, and is formed in a frame shape on the outer peripheral portion of the lower surface 25b of the flat plate portion 251. The support column 253 projects from the lower surface 25b of the flat plate portion 251 exposed in the opening 25x toward the metal layer 12. In the example of FIG. 11, four columns 253 are provided, but one to three columns or five or more columns may be provided. The lower surface of the side wall portion 252 of the metal layer 25A is directly joined to the outer peripheral portion of the upper surface of the metal layer 12. Further, the lower surface of each column 253 of the metal layer 25A is directly joined to a predetermined position on the upper surface of the metal layer 12.

To produce the metal layer 25A, for example, a metal sheet is prepared, a solid first resist layer is formed on the entire upper surface of the metal sheet, and the outer peripheral portion of the lower surface of the metal sheet (the portion serving as the side wall portion 252). And the second resist layer is selectively formed in the forming portion of the support column 253. Then, the portion exposed from the second resist layer on the lower surface side of the metal sheet is half-etched. As a result, a bottomed opening 25x is formed on the central side, a side wall portion 252 surrounding the opening 25x is formed on the outer peripheral side, and a support column 253 is formed in the opening 25x. For half-etching of the metal layer 25A, for example, a ferric chloride solution can be used. Then, by peeling the first and second resist layers with a stripping liquid, the metal layer 25A in which the flat plate portion 251 and the side wall portion 252 and the support column 253 are integrally formed is completed.

By providing the support 253 inside the side wall portion 252 formed in the frame shape of the metal layer 25A in this way, when the heat pipe 2A is manufactured, the metal layer 11 is formed in the same process as in FIG. 4D. It is possible to prevent the metal layer 25A from being crushed when the 12 and 25A are sequentially laminated and pressed. Further, when the heat pipe 2A is operating, it is possible to prevent the metal layer 25A from being deformed and the gas phase portion 21 from being crushed. Other effects are as shown in the first embodiment and the second embodiment.

Although the preferred embodiment has been described in detail above, it is not limited to the above-described embodiment, and various modifications and substitutions are made to the above-described embodiment without departing from the scope of claims. Can be added.

For example, the first embodiment and the modified examples 1 to 4 can be carried out in appropriate combinations. Further, the second embodiment and the modified example 1 and the modified examples 2 to 4 of the first embodiment can be carried out in an appropriate combination.

1,1A, 1B, 1C, 1D Heat pipe 11, 12, 13, 14, 25, 25A Metal layer 12x, 12y Through hole 13x Through hole 14a Upper surface of metal layer 14 15 Strut 21 Gas phase part 22 Liquid flow path part 23 Ventilation part 25a Upper surface of metal layers 25 and 25A 25b Lower surface of metal layers 25 and 25A 25x Openings 121, 121a, 121b, 121c, 121d, 122 Bottomed holes 123, 123a, 123b, 125 Pore 251 Flat plate part 252 Side wall part 253 props

Claims (13)

A heat pipe comprising a steam layer for moving vapor vaporized by the working fluid and a liquid layer for moving the working fluid liquefied by the steam.
The liquid layer has a plurality of first bottomed holes recessed from one surface side and arranged apart from each other, a plurality of second bottomed holes recessed from the other surface side, and the first bottomed hole. The first pore formed by partially communicating the bottomed hole and the second bottomed hole and the side surface of the adjacent second bottomed hole were formed by partially communicating with each other. Consists of a first metal layer with a second pore and
The steam layer is a heat pipe comprising a second metal layer formed in a frame shape so as to expose the plurality of first bottomed holes on one surface of the first metal layer. .. A heat pipe comprising a steam layer for moving vapor vaporized by the working fluid and a liquid layer for moving the working fluid liquefied by the steam.
The liquid layer has a plurality of first bottomed holes recessed from one surface side and arranged apart from each other, a plurality of second bottomed holes recessed from the other surface side, and the first bottomed hole. The first pore formed by partially communicating the bottomed hole and the second bottomed hole and the side surface of the adjacent second bottomed hole were formed by partially communicating with each other. Consists of a first metal layer with a second pore and
The heat pipe is characterized in that the steam layer is composed of a concave-shaped second metal layer formed on one surface of the first metal layer. The claim is characterized in that the area of the portion of the first bottomed hole that opens on the one surface side is smaller than the area of the portion of the second bottomed hole that opens on the other surface side. The heat pipe according to 1 or 2. The inner wall of the first bottomed hole widens from the first pore side toward the one surface side.
The heat pipe according to any one of claims 1 to 3, wherein the second bottomed hole widens the inner wall from the first pore side toward the other surface side. The heat pipe according to any one of claims 1 to 4, wherein a plurality of the first bottomed holes communicate with one of the second bottomed holes. The first to fifth aspects of claim 1 to 5, wherein the first bottomed hole has a region where the first bottomed hole is arranged at a high density, and the first bottomed hole has a region where the first bottomed hole is arranged at a low density. The heat pipe according to any one item. The heat pipe according to any one of claims 1 to 6, wherein the first bottomed hole includes a bottomed hole having a portion having a different area on the one surface side. The concave-shaped second metal layer is characterized in that a flat plate portion and a side wall portion protruding from the outer peripheral portion of the flat plate portion toward the first metal layer are integrally formed. Item 2. The heat pipe according to item 2. A step of forming a second metal layer forming a vapor layer for moving vapor vaporized by the working fluid, and a step of forming a first metal layer forming a liquid layer for moving the working fluid liquefied by the vapor. A method for manufacturing a heat pipe, comprising a step of joining the second metal layer on one surface of the first metal layer.
The step of forming the first metal layer is
The first metal sheet is half-etched from one surface side to form a plurality of first bottomed holes, the first metal sheet is half-etched from the other surface side, and the second bottomed holes are formed. A second fine particle formed by forming a plurality of the first pores and partially communicating with the first bottomed hole and partially communicating with the side surface of the adjacent second bottomed hole. Has a process of forming holes,
The step of forming the second metal layer is
A method for manufacturing a heat pipe, which comprises a step of forming a through hole penetrating a second metal sheet in the thickness direction. A step of forming a second metal layer provided with a side wall portion forming a vapor layer for moving vapor vaporized by the working fluid, and a first metal layer forming a liquid layer for moving the working fluid liquefied by the steam. A method for manufacturing a heat pipe, comprising a step of forming the first metal layer and a step of joining the second metal layer on one surface of the first metal layer.
The step of forming the first metal layer is
The first metal sheet is half-etched from one surface side to form a plurality of first bottomed holes, the first metal sheet is half-etched from the other surface side, and the second bottomed holes are formed. A second fine particle formed by forming a plurality of the first pores and partially communicating with the first bottomed hole and partially communicating with the side surface of the adjacent second bottomed hole. Has a process of forming holes,
The step of forming the second metal layer is
It has a step of half-etching the second metal sheet from one surface or the other surface side to form a bottomed opening on the center side and a side wall portion surrounding the opening on the outer peripheral side. A method for manufacturing a heat pipe. The claim is characterized in that the area of the portion of the first bottomed hole that opens on the one surface side is smaller than the area of the portion of the second bottomed hole that opens on the other surface side. The method for manufacturing a heat pipe according to 9 or 10. The inner wall of the first bottomed hole widens from the first pore side toward the one surface side.
The heat pipe according to any one of claims 9 to 11, wherein the second bottomed hole widens the inner wall from the first pore side toward the other surface side. Production method. The method for manufacturing a heat pipe according to any one of claims 9 to 12, wherein a plurality of the first bottomed holes communicate with one of the second bottomed holes. ..

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