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] The present invention relates to a heat sink having a structure imitating the roots of a tree, which structure is suitable for generating turbulent flow and thus has a high heat dissipation effect.

Background Art

[0002] Heat sinks are used to release heat generated by heat-generating elements of electronic devices and the like. As heat sinks, there are many types in which a plurality of fin-shaped heat dissipation parts are erected on the surface opposite to one surface of the base part in contact with the heat-generating body, or a plurality of pin-shaped (prismatic or cylindrical) heat dissipation parts are erected. In recent years, the performance of electronic devices, automotive parts, etc. has been remarkably improved. The heat generation amount of the electronic components mounted on these has increased, and the heat generation density has also increased due to the progress of miniaturization and thinning of electronic devices, etc. Therefore, it has become increasingly important to keep the heat-generating components mounted on electronic devices, etc. at an appropriate temperature. For this reason, the demand for heat sinks with high heat dissipation effects is constantly increasing. Inventions related to heat sinks, which are indispensable for electronic devices and the like, have been filed in large numbers, including the following Patent Documents 1 and 2.

[0003] The natural air-cooled heat sink according to the invention disclosed in Patent Document 1 includes a base and a stepped fin structure having n (n = 2, 3, ···) steps erected on the base. The fin structure of the i (i = 2, 3, ···, n) -th step of the stepped fin structure is erected with the fin structure of the (i - 1) -th step as a base, and the total cross-sectional area of the fin structure of the i -th step is smaller than the total cross-sectional area of the fin structure of the (i - 1) -th step. In the heat sink of this invention, since the total cross-sectional area of the fin structure closer to the base is larger, the conduction heat resistance decreases, and the heat diffusion performance and heat conduction performance increase. On the other hand, the heat dissipation surface area of the fin structure far from the base is increased, and the heat dissipation performance increases.

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

[0005] [Patent Document 1] Japanese Patent Publication No. 2017-17178 [Patent Document 2] Japanese Patent Publication No. 2016-27598 [Overview of the project] [Problems that the invention aims to solve]

[0006] According to the heat sink disclosed in Patent Document 1, it is possible to achieve a balance between thermal diffusion performance, thermal conduction performance, and heat dissipation performance, thereby lowering the temperature of the heat-generating element. However, the following problems exist. Specifically, firstly, the design primarily relies on natural air cooling. However, since heat sinks can utilize various cooling methods such as air cooling, liquid cooling, misting, and solid (dry ice powder), a structure that can be used with any of these methods is desirable. Secondly, because the wind only blows in one direction, turbulence does not occur. Therefore, with upright, wall-like fins, a temperature difference occurs between the side where the wind blows and the opposite side. Thirdly, referring to Figures 1 and 5 of Patent Document 1, it can be seen that there are multiple interface surfaces. It is thought that heat loss occurs at these interface surfaces due to obstruction of heat transfer. Fourthly, the individual fins and pins do not appear to have any innovations compared to existing designs. A predominantly linear structure is employed, but it is not adapted to environments such as air cooling, liquid cooling, and misting.

[0007] The heat sink disclosed in Patent Document 2 can generate turbulence, thus improving heat dissipation. However, judging from Figures 1 and 2 of Patent Document 2, there are too many straight lines. This does not generate sufficient turbulence. The inventor's concerns regarding "straight lines" will be discussed later.

[0008] Conventional heat sink structures, including those described in Patent Document 1, generate very little turbulence, even if they have a large number of densely packed fins or pins, because their shape is regular. Patent Document 2 shows ingenuity in the arrangement of fins and the shape of pins to consider the generation of turbulence, but the generation of turbulence is not sufficient. Because of these problems, conventional heat sink structures cannot fully utilize their surface area, and therefore the heat distribution tends to concentrate at the center, as shown by the ellipse bp in Figure 5(1).

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

[0010] To solve the above problems, the heat sink of the present invention is It comprises a base portion having a contact surface that comes into contact with the object to be cooled, and a heat dissipation portion provided on the side of the base portion opposite to the contact surface, The heat dissipation section is characterized by comprising a porous section and a pin structure section.

[0011] This invention is inspired by the structure of trees. Tree roots require a large amount of water. Similarly, heat sinks require a large amount of heat dissipation. Although the directions of "intake" and "exit" are different, the intended function is the same. Although the detailed structure of tree roots differs depending on the tree species, they all share a common structure that requires water, consisting of a continuous xylem, taproot, and fibrous roots, and all trees absorb water very efficiently. This structure can be applied to heat dissipation, whether using air cooling or liquid cooling, which is essential for heat sinks.

[0012] Tree roots do not have straight sections, but here I would like to state the inventor's view on "straightness." The inventor has never before observed a straight line in the parts of a living organism that sustain life. There are probably various reasons for this, but one possible reason is as follows: A single organism forms cells one by one, and these aggregates form tissue. It is presumed that a non-linear shape is advantageous for the tissue formed in this way to perform its functions most efficiently (e.g., heat dissipation, heat retention, circulation, etc.). In the case of heat retention, special chemical substances are produced to prevent heat loss or insulation, but even then, the body is designed to efficiently distribute heat throughout the tissue or living organism. In the case of heat dissipation, the structure of human lung tissue and the body also works to dissipate heat and retain warmth. The structure of the lungs of mammals, including humans, branches out from the trachea to the alveoli, and this structure is similar to that of tree roots, where fibrous roots branch out from the main root to the ends. In the embodiments described below, the heat sink of the present invention is applied to the roots of a tree, and it is important to adopt a structure that mimics that of a living organism. Not limited to tree roots or mammalian lungs, there are likely other suitable tissues and structures in nature. When mimicking living organisms, the key point to consider is that the medium (air or liquid in the case of a heat sink) must be in contact with the tissue (the heat dissipation part of the heat sink) for as long as possible, and the shape must be winding or curved to create the best possible form for generating turbulence. In addition, since an intricate surface can be realized, there is also the advantage of being able to freely adjust the surface area.

[0013] The method for manufacturing the heat sink of the present invention is as follows: The base portion and the heat dissipation portion are formed using a 3D printer. The heat sink of this invention has many parts that do not exhibit a geometric shape, and moreover, it has a structure that is continuously connected like the roots of a tree, with no boundaries whatsoever. Until 3D printers were put into practical use, there were no suitable means to realize such a unique shape and structure for an industrial product. However, now that 3D printing technology using aluminum powder such as AlSi10Mg, which can also be used as a heat dissipation material, and copper as raw materials has become widespread, it has become possible to manufacture heat sinks with a continuous structure like the roots of a tree. Incidentally, while there are various methods for 3D printing, the basic principle is to gradually form 3D structures in the smallest possible units. This is similar to the formation of biological tissue. From this perspective, it can be said that using a 3D printer to manufacture the heat sink of this 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 pace, 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 with a high heat dissipation effect that surpasses that of conventional products. [Brief explanation of the drawing]

[0015] [Figure 1] This diagram illustrates the structure of the heatsink in this embodiment. [Figure 2] This is a diagram illustrating an air-cooling unit equipped with a heatsink according to this embodiment. [Figure 3] This diagram illustrates the shape of the heat sink in this embodiment, from the base portion (corresponding to the woody part of a tree) to the porous portion (corresponding to the main root of a tree). [Figure 4] This figure illustrates the shape of the pin structure (corresponding to the root hairs of a tree) of the heat sink in this embodiment. [Figure 5](1) shows the general fin or pin shape of a conventional heat sink, and (2) is a diagram showing the portion that is efficiently cooled. [Figure 6] It is a diagram showing a further development example of the heat sink of the present embodiment.

Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the heat sink of the present invention will be described while referring to the accompanying drawings. Note that the following embodiments are merely examples, and the scope of rights of the present invention is determined based on the claims.

[0017] As shown in FIG. 1, the heat sink 1 is composed of a base portion 2 and a heat radiating portion 3. FIG. 2 is a diagram showing the basic structure of the air-cooling unit 10 using the heat sink 1. One surface of the base portion 2 is in contact with the Peltier module 11 which is the object to be cooled. The surface of the base portion 2 on the opposite side of the contact surface with the Peltier module 11 is continuous with the heat radiating portion 3. The heat radiating portion 3 is formed of a porous portion 31 and a pin structure portion 32 continuous with this, and an air-cooling fan 12 is positioned near the tip portion of the pin structure portion 32. Note that FIG. 2 is an example of an air-cooling unit, but in the case of liquid cooling, a method such as surrounding the entire heat sink with a container and circulating a liquid with a pump may be employed.

[0018] The base portion 2 corresponds to the trunk of a tree in relation to the roots. This portion is made flat in order to closely adhere to the Peltier module 11 well like grafting. It is necessary to make it as thin as possible in order to efficiently dissipate the heat generated by the Peltier module 11, but it is designed by adjusting to the most suitable thickness in terms of structure and efficiency. By continuously forming with the density changing to the porous portion 31 of the heat radiating portion 3, the loss of heat transfer due to the boundary surface with the heat radiating portion 3 is reduced.

[0019] The porous section 31 of the heat dissipation section 3 corresponds to the main root of a tree. In many conventional heat sinks, fins or pins are directly erected from the base section. However, in heat sink 1, there is a porous section 31 that extends seamlessly from the base section 2, and the pin structure section 32 extends seamlessly from this porous section 31. In other words, the pin structure section 32, which corresponds to the fins or pins of conventional products, is not directly disposed on one side of the base section 2, but is indirectly disposed on the base section 2 via the porous section 31. The porous section 31, which was not present in conventional products, is necessary to generate turbulence and to achieve a larger surface area than the base section 2. Like the roots of a tree, the porous section 31 is interposed, becoming less dense from the center outward from the base section 2 (corresponding to the wood), and further, to increase the overall surface area of ​​the root, it transitions continuously to the pin structure section 32, minimizing the occurrence of an interface between the porous section 31 and the pin structure section 32. Because heatsink 1 has this structure, it has higher heat dissipation efficiency even if it has the same volume as a conventional heatsink. The pin structure portion 32 of the heat dissipation section 3 is a necessary part for achieving a large surface area.

[0020] Figure 3(1) illustrates a typical shape from the base portion 2 to the porous portion 31, but it should be molded in a shape that is most suitable for the cooling medium, such as air cooling or liquid cooling. A cluster structure (as shown in (2) to (4)) is also possible (although the clusters are drawn regularly in this example, the arrangement of these clusters does not need to be regular).

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

[0022] On the other hand, it can also be argued that using a 3D printer makes it possible to create heatsinks that continuously and freely change shape, much like the roots of a tree. The concept of "continuous change" is extremely important for the heat sink of this invention. And for continuous change to occur, there must be no interface. If there is an interface, a significant loss of heat transfer occurs at that interface. Furthermore, without an interface, it can receive air or liquid flow from multiple directions. This makes heat dissipation more efficient by air or liquid flow from various directions, giving flexibility to the structure of the air-cooled or water-cooled unit. Moreover, it is possible to create various shapes, including cluster structures (see Figures 3(2)~(4)), to adapt to various environments such as sandy soil, waterside, rocky areas, fertile soil, and soil, and an efficient structure can be adopted for each cooling method, such as natural air cooling, air cooling, liquid cooling, spray (mist), or solid (dry ice powder).

[0023] Using a 3D printer also has the following benefits: In other words, since objects formed by 3D printing can be considered as a collection of points, it is possible to create lighter products than metal products made by mold processing, etc. Regarding breathability, micro-level processing can be freely performed depending on the design, so optimal breathability can be achieved.

[0024] Heatsink 1 can dissipate heat generated over a wide area. (Gray area in Figure 2) AP is the part that is cooled efficiently. In contrast, many heatsinks currently on the market have the following problems: Figure 5(1) shows a structure common to most current heatsinks 100, but even though the fin or pin structure is dense, it has a regular shape. As a result, turbulence is hardly generated, and the large surface area is not fully utilized. Consequently, 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 heatsink 1 should be understandable.

[0025] The basic structure and effects of heatsink 1 have been described above, but this is merely one embodiment of the present invention. In terms of basic structure, the base portion 2 is usually flat in order to be in close contact with the heat source or coolant. However, if the mating object (Peltier element, LSI, semiconductor, or other object requiring heat dissipation) has irregularities or flexibility in shape, the shape of the base portion 2 does not need to be flat, and it can be adapted to the object to be heated. Figures 3(3) and 3(4) show an example of this.

[0026] As a further development of the heat sink 1, as shown in Figure 6, the porous portion 31 or the pin structure portion 32 may be made into a hollow framework, and the inside of the cavity may be filled with a liquid such as pure water, similar to 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, we can expect demand for a product that exhibits a higher heat dissipation effect than conventional products. [Explanation of Symbols]

[0028] 1: Heatsink 2: Base section (the part corresponding to the wood of a tree) 3: Heat dissipation part 31: Porous part (the part corresponding to the main root) 32: Pin structure (part corresponding to the root hairs)

Claims

1. A base portion having a contact surface that comes into contact with the object to be cooled, This base portion includes a heat dissipation section provided on the side opposite to the contact surface, The heat dissipation section is characterized by comprising a porous section corresponding to the main root of a large tree and a pin structure section corresponding to fibrous roots, and by a continuous change without any interface.

2. The heat sink according to claim 1, characterized in that the base portion takes a shape that conforms to the shape of the heat source or cooler in close contact with it.

3. The heat sink according to claim 1, characterized in that the inside of the framework of the porous portion and the pin structure portion is hollow, and the inside of the hollow is filled with liquid.

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

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