Heat sink

Abstract

To provide a heat sink having a structure suitable for generation of a turbulent flow following the roots of trees and having a high heat radiation effect.SOLUTION: A heat sink 1 includes a base part 2 having a contact surface in contact with an object to be cooled, and a heat radiation part 3 provided on a surface opposite to the contact surface in the base part 2, and the heat radiation part 3 includes a porous part 31 corresponding to a main root of a large tree and a pin structure part 32 corresponding to a fibrous root, and continuously changes without having a boundary surface. Since the heat sink 1 does not have a geometric shape but has a highly flexible shape, it is manufactured by a 3D printer that forms a 3D structure little by little in the smallest possible unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This heat sink has a structure modeled after tree roots, which is suitable for generating turbulent flow and therefore has a high heat dissipation effect. [Background technology]

[0002] Heat sinks are used to release heat generated by heat-generating elements in electronic devices. Many heat sinks have multiple fin-shaped heat dissipation parts or multiple pin-shaped (rectangular or cylindrical) heat dissipation parts on the opposite side of one side of the base that comes into contact with the heat-generating element. In recent years, the performance of electronic devices, automotive parts, etc. has improved significantly, and the amount of heat generated by the electronic components installed in these devices has increased. At the same time, the heat density has also increased due to the progress in miniaturization and thinning of electronic devices. Therefore, it is becoming increasingly important to maintain the heat-generating components installed in electronic devices at an appropriate temperature. For this reason, the demand for heat sinks with high heat dissipation efficiency is only increasing. Many inventions relating to heat sinks, which are essential for electronic devices, have been filed, including Patent Documents 1 and 2 listed below.

[0003] The natural-cooling heat sink according to the invention disclosed in Patent Document 1 comprises a base and an n-stage (n=2, 3, . . .) stepped fin structure erected on the base, with the i-th (i=2, 3, . . . , n)-th fin structure of the stepped fin structure erected on the (i-1)-th fin structure as a base, and the total cross-sectional area of ​​the i-th fin structure is smaller than the total cross-sectional area of ​​the (i-1)-th fin structure. In this heat sink, the total cross-sectional area of ​​the fin structures closer to the base is larger, thereby reducing conductive thermal resistance and improving thermal diffusion and conduction performance. On the other hand, the heat dissipation surface area of ​​the fin structures farther from the base is increased, thereby improving heat dissipation performance.

[0004] The invention disclosed in Patent Document 2 aims to provide a heat sink that can improve heat dissipation, and comprises a plate-shaped base portion having a contact surface that comes into contact with the object to be cooled, and a plurality of heat dissipation portions erected on the surface of the base portion opposite the contact surface, and the heat dissipation portions are shaped to be bent or curved multiple times along a direction perpendicular to the opposite surface. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2017-17178 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-27598 Summary of the Invention [Problem to be solved by the invention]

[0006] The heat sink disclosed in Patent Document 1 is capable of achieving both thermal diffusion performance, thermal conduction performance, and heat dissipation performance, thereby lowering the temperature of the heat-generating element. However, it has the following problems. First, the design focuses on natural cooling. However, heat sinks can be cooled by various methods, including air cooling, liquid cooling, mist (mist), and solid (dry ice powder), so a structure that can be used with all of these methods is desirable. Second, because the air only blows in one direction, turbulence does not occur. Therefore, with upright wall-like fins, a temperature difference occurs between the side where the air blows and the opposite side. Third, referring to Figures 1 and 5 of Patent Document 1, it can be seen that there are multiple boundary surfaces. It is likely that losses occur due to the obstruction of heat transfer at these boundary surfaces. Fourth, the individual fins and pins do not represent any innovations on existing designs. A primarily linear structure is adopted, but the shape is not adapted to environments such as air cooling, liquid cooling, and mist cooling.

[0007] The heat sink disclosed in Patent Document 2 can generate turbulence, thereby improving heat dissipation. However, looking at Figures 1 and 2 of Patent Document 2, there are too many straight lines, which does not generate enough turbulence. The inventor's concerns about "straight lines" will be discussed later.

[0008] In conventional heat sink structures, including those described in Patent Document 1, even if numerous fins or pins are densely packed, they have a regular shape, so turbulence is hardly generated. Patent Document 2 takes into consideration the generation of turbulence by devising fin arrangements and pin shapes, but the generation of turbulence is insufficient. Due to these problems, conventional heat sink structures are unable to fully utilize their surface area, and as a result, heat distribution tends to be concentrated at the center of the ellipse bp in Figure 5(1).

[0009] In view of these problems, the present invention aims to propose a heat sink with a heat dissipation section that has a novel structure modeled after tree roots in order to fully utilize the heat dissipation effect.Moreover, the present invention aims to achieve this objective from the perspective that it is important to break away from the conventional heat dissipation section structure that has a geometric shape consisting of almost straight lines (with some circular arcs). [Means for solving the problem]

[0010] In order to solve the above problems, the heat sink of the present invention has: a base portion having a contact surface that comes into contact with an object to be cooled; and a heat dissipation portion provided on a surface of the base portion opposite to the contact surface, The heat dissipation portion is characterized by comprising a porous portion and a pin structure portion.

[0011] This invention was inspired by the structure of trees. Tree roots require a large amount of water. Similarly, a heat sink needs to dissipate a large amount of heat. Although the direction of "input" and "output" differs, the intended function is the same. Although the detailed structure of tree roots varies depending on the species, they all share a common structure that requires water, consisting of xylem, taproot, and fibrous roots, and all trees absorb water very efficiently. This structure can be applied to the heat dissipation required for heat sinks, whether they are air-cooled or liquid-cooled.

[0012] There are no straight parts in the roots of a tree, but here I would like to explain the inventor's view on "straight lines." The inventor has never seen a straight line in the parts of an organism that maintain life. There are probably various reasons for this, but one possible reason is as follows: an organism forms cells one by one, and these cells aggregate to form tissues. It is speculated that a non-linear shape is advantageous for these tissues to perform their tasks (such as heat dissipation, insulation, circulation, etc.) most efficiently. In the case of keeping warm, special chemicals are produced to prevent heat loss or insulation, but even so, the tissue or organism is designed to efficiently disperse heat throughout the organism. In the case of heat dissipation, the structure of human lung tissue and the body also works to disperse heat and retain heat. The lung structure of mammals, including humans, branches from the trachea and leads to the alveoli, and this structure is similar to that of tree roots, where fibrous roots branch out from the taproot and reach the terminal ends. In the following embodiment, the heat sink of the present invention is applied to tree roots, but the adoption of a biologically-based structure is important. There are likely other suitable tissues and structures in nature, not limited to tree roots or mammalian lungs. When imitating a living organism, attention should be paid to the fact that the medium that needs to be dispersed as much as possible (air or liquid in the case of a heat sink) must be in contact with the tissue (the heat dissipation portion in the case of a heat sink) for as long as possible, and a shape that is twisted or curved and optimal for generating turbulence must be pursued. Another advantage is that the ability to realize complex surfaces allows for the surface area to be freely adjusted.

[0013] The method for manufacturing a heat sink of the present invention includes the steps of: The base portion and the heat dissipation portion are formed using a 3D printer. The heat sink of the present invention does not have a geometric shape in most parts, and has a continuous structure like the roots of a tree, with no boundaries. Until 3D printers became practical, there were no suitable means to realize such unique shapes and structures as industrial products. However, with the spread of 3D printer technology using aluminum powder such as AlSi10Mg, which can also be used as a heat dissipation material, and copper as raw materials, it has become possible to manufacture heat sinks with a continuous structure like the roots of a tree. By the way, there are various methods for 3D printers, but the basic principle is to gradually form 3D tissue in the smallest possible units. This is similar to the formation of biological tissue. From this point of view, it can be said that using a 3D printer to manufacture the heat sink of the present invention is inevitable. The inventor predicts that with the advent of 3D printers, industrial products with mechanical structures modeled after living organisms will appear at an accelerating rate in the future, and the heat sink of the present invention is one such industrial product modeled after living organisms. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a heat sink having a high heat dissipation effect that surpasses that of conventional products. [Brief explanation of the drawings]

[0015] [Figure 1] 1A and 1B are diagrams illustrating the structure of a heat sink according to an embodiment of the present invention. [Figure 2] 1A and 1B are diagrams illustrating an air-cooling unit equipped with a heat sink according to an embodiment of the present invention. [Figure 3] 3 is a diagram illustrating an example of the shape of a heat sink according to the present embodiment, from a base portion (corresponding to the xylem of a tree) to a porous portion (corresponding to the taproot of a tree). FIG. [Figure 4] 3A and 3B are diagrams illustrating examples of the shape of pin structures (corresponding to the roots of a tree) of the heat sink of this embodiment. [Figure 5](1) shows the typical fin or pin shape of a conventional heat sink, and (2) shows the part that is cooled efficiently. [Figure 6] 10A and 10B are diagrams illustrating further development examples of the heat sink of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the heat sink of the present invention will be described with reference to the accompanying drawings. The following embodiments are merely examples, and the scope of the present invention is determined by the claims.

[0017] As shown in FIG. 1, the heat sink 1 comprises a base portion 2 and a heat dissipation portion 3 . 2 is a diagram showing the basic structure of an air-cooling unit 10 using a heat sink 1, with one surface of a base 2 in contact with a Peltier module 11, which is the object to be cooled. The surface of the base 2 opposite the surface in contact with the Peltier module 11 is continuous with a heat dissipation section 3, which is formed from a porous section 31 and a pin structure section 32 continuing from the porous section 31, and an air-cooling fan 12 is located near the tip of the pin structure section 32. Note that Figure 2 shows an example of an air-cooled unit, but in the case of liquid cooling, a method such as enclosing the entire heat sink in a container and circulating the liquid with a pump can be used.

[0018] If we compare the base part 2 to a tree, it corresponds to the xylem relative to the roots. This part is made flat so that the Peltier module 11 can be attached tightly, like a graft. It needs to be as thin as possible to efficiently dissipate the heat generated by the Peltier module 11, but it is designed with an optimal thickness adjusted for both structure and efficiency. By continuously changing the density to form the porous part 31 of the heat dissipation part 3, heat transfer loss at the interface with the heat dissipation part 3 is reduced.

[0019] The porous portion 31 of the heat dissipation unit 3 corresponds to the taproot of a tree. In many conventional heat sinks, fins or pins are erected directly from the base. However, in the heat sink 1, the porous portion 31 is continuous with the base 2 without any boundaries, and the pin structure 32 is continuous with this porous portion 31 without any boundaries. In other words, the pin structure 32, which corresponds to the fins or pins of conventional products, is not directly disposed on one side of the base 2, but is indirectly disposed on the base 2 via the porous portion 31. The porous portion 31, which does not exist in conventional products, is necessary to generate turbulence and achieve a larger surface area than the base 2. Like the roots of a tree, the porous portion 31 becomes sparser from the center of the base 2 (corresponding to the xylem) to the outside, and then transitions continuously to the pin structure 32 to increase the surface area of ​​the entire root, minimizing the boundary between the porous portion 31 and the pin structure 32. Because the heat sink 1 has this structure, it has a higher heat dissipation efficiency even if it has the same volume as a conventional heat sink. The pin structure 32 of the heat dissipation part 3 is a part necessary for realizing a large surface area.

[0020] 3(1) shows an example of a general shape from the base portion 2 to the porous portion 31, but it may be formed in a shape that is most suitable for a cooling medium such as air cooling or liquid cooling. Cluster structures such as those shown in (2) to (4) may also be used (the clusters are drawn as regular patterns, but the clusters do not need to be regular).

[0021] 4 shows an example of the shape of the pin structure 32. This part should not have a straight pin structure, but should have a structure with (1) branches or dispersion, or (2) twists, depending on the cooling medium, such as air cooling or liquid cooling. This is because, compared to a straight structure, the surface area is larger and it is more suitable for generating turbulence. However, as with the porous portion 31, the problem is that it has a non-geometric, irregular shape and cannot be formed using a mold, etc. Therefore, the use of a 3D printer is essential.

[0022] On the other hand, it can also be said that it was only by using a 3D printer that it became possible to create a heat sink whose shape can be continuously and freely changed like the roots of a tree. The "continuous change" mentioned here is crucial for the heat sink of the present invention. Furthermore, to achieve this continuous change, there must be no boundaries. If there were boundaries, there would be the disadvantage of increased heat transfer loss at those boundaries. Furthermore, the absence of boundaries allows for wind and liquid flow from multiple directions. This allows for efficient heat dissipation through wind and liquid flow from various directions, providing greater flexibility in the design of the air-cooled or water-cooled unit. Furthermore, various shapes, including cluster structures (see Figures 3(2)-(4)), can be created to accommodate various environments, such as sandy soil, waterside, rocky areas, fertile soil, and soil. This allows for efficient designs for various cooling methods, including natural air cooling, air cooling, liquid cooling, spray (mist), and solid (dry ice powder).

[0023] The use of 3D printers also has the following benefits: In other words, because the objects formed by 3D printers can be considered as a collection of points, it is possible to create products that are lighter than metal products made by mold processing, etc. In terms of breathability, it is also possible to freely process at the micro level depending on the design, so optimal breathability can be achieved.

[0024] The heat sink 1 can dissipate the generated heat over a wide area. The ap is the part that is cooled efficiently. In contrast, many heat sinks currently on the market have the following problems. Figure 5(1) shows a structure common to most current heat sinks 100. Even if the fin or pin structure is dense, it has a regular shape. As a result, there is almost no turbulence, and the large surface area is not fully utilized. Therefore, the heat distribution tends to concentrate in the center, as shown by the ellipse bp in Figure 5(1), and only the gray area cp inside the dashed line in Figure 5(2) is efficiently cooled. Comparing this with the gray area ap inside the dashed line in Figure 2, the high heat dissipation performance of the heat sink 1 is clear.

[0025] The basic structure and effects of the heat sink 1 have been described above, but this is merely an embodiment of the present invention. As a basic structure, the base part 2 is usually kept flat to be in close contact with the heat source or cooling body, but if the other side (Peltier, LSI, semiconductor, or other object that requires heat dissipation) has irregularities or freedom of shape, the shape of the base part 2 does not need to be flat, and it is better to make it a shape that conforms to the object to dissipate heat. Figure 3 (3) and (4) are examples of this.

[0026] As a further development of the heat sink 1, the porous portion 31 or the pin structure portion 32 may be made into a hollow skeleton as shown in Fig. 6, and the hollow may be filled with a liquid such as pure water like a heat pipe structure. This can further promote heat dissipation. [Industrial Applicability]

[0027] By providing a heat sink with a novel structure that applies biological structures to mechanical structures, demand is expected to grow for a product that exhibits greater heat dissipation effects than conventional products. [Explanation of symbols]

[0028] 1: Heat sink 2: Base (corresponding to the wood of the tree) 3: Heat dissipation part 31: Porous part (corresponding to the taproot) 32: Pin structure part (corresponding to the root of the hair)

Claims

1. a base portion having a contact surface that comes into contact with the object to be cooled; a heat dissipation portion provided on a surface of the base portion opposite to the contact surface, The heat sink is characterized in that the heat dissipation portion is made up of a porous portion corresponding to the taproot of a large tree and a pin structure portion corresponding to the roots of the tree, and is continuously changing without having any boundary surface.

2. 2. The heat sink according to claim 1, wherein the base portion has a shape adapted to the shape of a heat source or cooling body that is in close contact with the base portion.

3. 2. The heat sink according to claim 1, wherein the inside of the porous portion and the skeleton of the pin structure is hollow, and the inside of the hollow is filled with a liquid.

4. A method for manufacturing the heat sink according to any one of claims 1 to 3, comprising the steps of: A method for manufacturing a heat sink, comprising forming the base portion and the heat dissipation portion using a 3D printer.

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