Heat sink and heat sink manufacturing method

Abstract

A heat sink according to the present invention comprises a base and a plurality of fins. The base has a main surface. The base has a flat plate shape. The plurality of fins protrude from the main surface of the base. Each of the plurality of fins has a first portion and a second portion. In the first portion, the surface area of a cross section orthogonal to the thickness direction decreases as the distance from the base increases in the thickness direction of the base. In the second portion, the surface area of a cross section orthogonal to the thickness direction increases as the distance from the first portion increases in the thickness direction. The second portion includes a distal end surface in the thickness direction.

Description

Heat sink and method for manufacturing a heat sink

[0001] The present disclosure generally relates to a heat sink and a method for manufacturing a heat sink, and more particularly to a heat sink having a plurality of fins and a method for manufacturing a heat sink.

[0002] Patent Document 1 discloses a heat sink. This heat sink includes fins on a base portion, thermally connects the base portion to a heat generating body, and cools the heat generating body. In this heat sink, the density occupied in the space of the fins is greater at the tip portion than at the root portion of the fins.

[0003] Japanese Patent Application Laid-Open No. 2000-260916

[0004] In a heat sink, improvement of heat dissipation performance is desired.

[0005] A heat sink according to an aspect of the present disclosure includes a base and a plurality of fins. The base has a main surface. The shape of the base is flat. The plurality of fins protrude from the main surface of the base. Each of the plurality of fins has a first portion and a second portion. In the first portion, the area of a cross section orthogonal to the thickness direction decreases as the distance from the base in the thickness direction of the base increases. In the second portion, the area of a cross section orthogonal to the thickness direction increases as the distance from the first portion in the thickness direction increases. The second portion includes a tip surface in the thickness direction.

[0006] A method for manufacturing a heat sink according to an aspect of the present disclosure is a manufacturing method for forming the heat sink by additive manufacturing.

[0007] According to the present disclosure, it is possible to improve the heat dissipation performance of the heat sink.

[0008] Figure 1 is a schematic cross-sectional view illustrating a heat sink according to an embodiment. Figure 2 is a perspective view showing the same heat sink. Figure 3 is a front view showing the same heat sink. Figure 4 is a schematic cross-sectional view showing the same heat sink. Figure 5 is a schematic cross-sectional view showing the same heat sink. Figure 6 is a schematic cross-sectional view showing the same heat sink. Figure 7 is a schematic cross-sectional view showing the same heat sink. Figure 8 is a schematic cross-sectional view showing the same heat sink. Figure 9 is a schematic cross-sectional view showing the same heat sink. Figure 10 is a schematic cross-sectional view showing the same heat sink. Figure 11 is a schematic cross-sectional view showing the same heat sink. Figure 12 is a schematic cross-sectional view showing the same heat sink. Figure 13 is a schematic plan view showing the same heat sink. Figure 14 is a graph showing the height and cross-sectional area ratio of the multiple fins provided by the heat sink. Figure 15 is a schematic cross-sectional view showing the edge fins provided by the heat sink of Modification 1.

[0009] Preferred embodiments of this disclosure will be described in detail below with reference to the drawings. Common elements in the embodiments described below are denoted by the same reference numerals, and redundant descriptions of common elements may be omitted. The embodiments and modifications described below represent only a portion of the various embodiments of this disclosure. Furthermore, the embodiments and modifications described below can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved. It is also possible to combine the configurations of the embodiments and modifications as appropriate.

[0010] The figures described in this disclosure are schematic diagrams, and the ratios of the size and thickness of each component in each figure do not necessarily reflect the actual dimensional ratios. Furthermore, the arrows indicating directions in the drawings are examples only and are not intended to specify the direction in which the heat sink 1 is used. Also, the arrows indicating directions in the drawings are for illustrative purposes only and do not represent actual structures.

[0011] (Embodiment) (1) Overview First, an overview of the heat sink 1 according to this embodiment will be described with reference to Figure 1.

[0012] The heat sink 1 is thermally connected to an object 9, such as a semiconductor component, which is a heat-generating element, and dissipates the heat transferred from the object 9.

[0013] As shown in Figure 1, the heat sink 1 comprises a base 2 and a plurality of fins 3.

[0014] The base 2 has a main surface 21 and a main surface 21A opposite to the main surface 21. The shape of the base 2 is flat. The main surfaces 21 and 21A are arranged in the thickness direction D1 of the flat base 2. In this embodiment, the thickness direction D1 is perpendicular to the main surface 21 and perpendicular to the main surfaces 21 and 21A.

[0015] Multiple fins 3 protrude from the main surface 21 of the base 2.

[0016] Each of the multiple fins 3 has a first portion 301 and a second portion 302.

[0017] In the first part 301, the area of ​​the cross-section perpendicular to the thickness direction D1 becomes smaller as the distance from the base 2 increases in the thickness direction D1 of the base 2.

[0018] In the second portion 302, the area of ​​the cross-section perpendicular to the thickness direction D1 increases as it moves further away from the first portion 301 in the thickness direction D1. The second portion 302 includes a tip surface 32 in the thickness direction D1.

[0019] In this disclosure, "orthogonal (perpendicular)" means not only a state where the angle between two objects is exactly 90 degrees, but also a state where the two objects intersect within a certain range of difference. In other words, the angle between two orthogonal objects falls within a certain range of difference from 90 degrees (for example, 10 degrees or less). That is, "orthogonal" in this disclosure includes cases where the angle between two objects is between 80 degrees and 100 degrees.

[0020] Furthermore, in the following explanation, the cross-section perpendicular to the thickness direction D1 of the fin 3 (first portion 301 and second portion 302) may be simply referred to as the "cross-sectional surface." Also, the area of ​​the cross-section perpendicular to the thickness direction D1 of the fin 3 (first portion 301 and second portion 302) may be simply referred to as the "cross-sectional area."

[0021] The fins 3 of the heat sink 1 in this embodiment have a shape in which the cross-sectional area decreases as it moves away from the base 2, and then increases again. This makes it easier to transfer heat from the base 2 to the fins 3 by making the cross-sectional area of ​​the base portion of the fins 3 relatively large. In this embodiment, the first portion 301 extends from the main surface 21 of the base 2 along the thickness direction D1, and the second portion 302 is connected to the first portion 301 at the boundary 33 and extends from the boundary 33 along the thickness direction D1 away from the base 2 and the first portion 301 to the tip surface 32. Furthermore, by making the cross-sectional area near the boundary 33 between the first portion 301 and the second portion 302 of the fins 3 relatively small, the airflow resistance to the wind passing between the multiple fins 3 can be reduced, thereby improving heat dissipation performance. In addition, by making the cross-sectional area of ​​the tip portion of the fins 3 relatively large, the heat dissipation performance at the tip surface 32, for example, can be improved. In other words, the heat sink 1 of this embodiment can improve heat dissipation performance.

[0022] (2) Details The detailed configuration of the heat sink 1 according to this embodiment will be described below with reference to Figures 1 to 14.

[0023] The heat sink 1 is thermally connected to an object 9, such as a semiconductor component, which is a heat-generating element, and dissipates the heat transferred from the object 9. In this embodiment, the heat sink 1 is thermally connected to the object 9 by being placed on top of the object 9. However, it is not essential that the heat sink 1 is provided on top of the object 9.

[0024] The material of heat sink 1 is mainly aluminum. However, the material of heat sink 1 may also be mainly other metals such as iron.

[0025] The heatsink 1 comprises a base 2 and a plurality of fins 3.

[0026] The shape of the base 2 is flat. As shown in Figure 2, the shape of the base 2 in this embodiment is a rectangular flat plate. The base 2 has a main surface 21. The main surface 21 may be a flat surface or an uneven surface. In the heat sink 1 of this embodiment, the surface of the base 2 opposite to the main surface 21 (main surface 21A) is thermally connected to the object 9.

[0027] As shown in Figures 1 to 3, the multiple fins 3 protrude from the main surface 21 of the base 2. Each fin 3 has a first portion 301 and a second portion 302.

[0028] The first portion 301 includes a root portion that is continuous with the base 2. The cross-sectional area decreases as it moves away from the base 2 in the thickness direction D1 of the base 2.

[0029] The second portion 302 is continuous with the first portion 301. In the second portion 302, the cross-sectional area increases as it moves away from the first portion 301 in the thickness direction D1. The second portion 302 includes a tip surface 32 in the thickness direction D1. The tip surface 32 is the tip surface of the fin 3. The first portion 301 is located between the second portion 302 and the base 2, and the second portion 302 is further away from the base 2 than the first portion 301.

[0030] The cross-sectional area of ​​the fin 3 decreases from the first end 31, which is the end on the base 2 side, toward the tip surface 32, and then increases. In the fin 3 of this embodiment, the cross-sectional area of ​​the fin 3 decreases from the first end 31, which is the end on the base 2 side, toward the tip surface 32, becomes minimal, and then increases. The cross-sectional area of ​​the fin 3 becomes minimal at the boundary 33 between the first part 301 and the second part 302.

[0031] Here, "the cross-sectional area of ​​fin 3 decreases" means not only that the cross-sectional area of ​​fin 3 decreases in a strictly continuous manner, but also that the cross-sectional area of ​​fin 3 increases in some parts. "The cross-sectional area of ​​fin 3 decreases" means that, when the distance between the base 2 and the cross-section is a predetermined distance (for example, about 2 mm), the cross-sectional area should decrease on average as the cross-section moves further away from the base 2. Conversely, "the cross-sectional area of ​​fin 3 increases" means not only that the cross-sectional area of ​​fin 3 increases in a strictly continuous manner, but also that the cross-sectional area of ​​fin 3 decreases in some parts. "The cross-sectional area of ​​fin 3 increases" means that, when the distance between the base 2 and the cross-section is a predetermined distance (for example, about 2 mm), the cross-sectional area should increase on average as the cross-section moves further away from the base 2.

[0032] Next, with reference to Figures 3 to 14, the relationship between the distance between the cross-sections of the base 2 and fins 3 of the heat sink 1 in this embodiment and the cross-sectional area of ​​the cross-sections will be explained.

[0033] In this embodiment, the distance Z1 (see Figure 3) between the tip surface 32 of the fin 3 and the main surface 21 of the base 2 (in other words, the first end 31 of the fin 3) is 10 mm. However, the distance Z1 can be set as appropriate. Figures 4 to 12 are schematic cross-sectional views showing the cross-sections of multiple fins 3 when the distance from the base 2 to the cross-section is 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, and 9 mm. Figure 13 is a schematic plan view showing the tip surface 32 of multiple fins 3.

[0034] The island-like regions shown in Figure 4 represent multiple cross-sections of the multiple fins 3. As shown in Figures 4 to 8, in the first portion 301 of the fin 3, the cross-sectional area decreases as it moves away from the base 2 in the thickness direction D1 of the base 2.

[0035] Here, viewed from the thickness direction D1, the first portion 301 does not overlap with the edge portion 22 (see Figure 5) of the main surface 21 of the base 2. In other words, the first portion 301 is not located on or above the edge portion 22. The absence of the first portion 301 on or above the edge portion 22 allows air to flow more easily between the multiple fins 3 of the heat sink 1, thereby improving the heat dissipation performance of the heat sink 1.

[0036] The edge portion 22 is an area within a predetermined distance X2 from the edge of the main surface 21 of the base 2. The predetermined distance X2 is, for example, 10% (or about 10%) of the distance X1 between the center and the edge of the main surface 21 of the base 2. However, the predetermined distance X2 may be 5% (or about 5%) of the distance X1, or 20% (or about 20%) of the distance X1, and may be set as appropriate.

[0037] As shown in Figures 9 to 13, in the second portion 302 of the fin 3, the cross-sectional area increases as it moves away from the base 2 in the thickness direction D1 of the base 2.

[0038] Here, as shown in Figures 9 to 13, the cross-section of the second portion 302 widens towards the edge 22 of the base 2 as it moves away from the first portion 301 in the thickness direction D1 (i.e., as it approaches the tip surface 32). This allows for an increase in the surface area (or volume) of the second portion 302, while suppressing an increase in airflow resistance near the center of the heat sink 1, thereby further improving the heat dissipation performance of the heat sink 1.

[0039] Furthermore, in this embodiment, the cross-section of the second portion 302 widens towards the edge 22 closest to the root portion (first end 31) of the fin 3 as it moves away from the first portion 301 in the thickness direction D1. For example, in the examples of Figures 9 to 13, the first fin 3A and the second fin 3B, which will be described later and are included in the plurality of fins 3, widen towards the edge 22 closest to the root portion of the fin 3 in the lower part of the paper in the figures.

[0040] As shown in Figure 13, the plurality of fins 3 includes a first fin 3A and a second fin 3B. In this embodiment, the first fin 3A and the second fin 3B are two adjacent fins 3 among the plurality of fins 3. The tip surface 32 of the first fin 3A and the tip surface 32 of the second fin 3B are continuous. This makes it easier for air to flow between the plurality of fins 3, and increases the surface area (or volume) of the second portion 302, thereby further improving the heat dissipation performance of the heat sink 1.

[0041] In this embodiment, a portion of the tip surface 32 of the first fin 3A and a portion of the tip surface 32 of the second fin 3B are continuous. Furthermore, a portion of the tip surface 32 of the first fin 3A and a portion of the tip surface 32 of the second fin 3B are continuous at the upper part of the edge 22 of the main surface 21 of the base 2. Also, as shown in Figure 13, not only the tip surfaces 32 of the first fin 3A and the second fin 3B, but also the tip surfaces 32 of two adjacent fins 3 among the multiple fins 3 may be continuous. In other words, the tip surfaces 32 of three or more fins 3 among the multiple fins 3 may be continuous.

[0042] Graph G1 in FIG. 14 is a graph showing the height and cross-sectional area ratio of a plurality of fins 3 provided in the heat sink 1. More specifically, graph G1 shows the total cross-sectional area of the plurality of fins 3 (i.e., the cross-sectional area of the heat sink 1) when the distance between the base 2 and the cross-section is 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, and the total cross-sectional area of the plurality of fins 3 (or the total area of the tip surfaces 32 of the plurality of fins 3, that is, the cross-sectional area of the heat sink 1) when the distance between the base 2 and the cross-section is 10 mm, and shows the area ratio with respect to the area of the main surface 21 of the base 2. Note that the area of the main surface 21 of the base 2 is the area including the portion where the plurality of fins 3 are formed. When the main surface 21 is square, the area of the main surface 21 is (X1 × 2). ,

[0046] , ,

[0045] ,

[0044] , , ,

[0048] , ,

[0047] is as follows.

[0043] For example, the portion where the distance between the base 2 and the cross-section is less than 5 mm is the first portion 301, the portion where the distance between the base 2 and the cross-section is 5 mm is the boundary 33 between the first portion 301 and the second portion 302, and the portion where the distance between the base 2 and the cross-section is 5 mm or more is the second portion 302. As shown in graph G1, in the first portion 301, the cross-sectional area becomes smaller as it moves away from the base 2 in the thickness direction D1 of the base 2. Also, in the second portion 302, the cross-sectional area becomes larger as it moves away from the first portion 301 in the thickness direction D1.

[0044] (3) Method for manufacturing a heat sink Next, a method for manufacturing the heat sink 1 of the present embodiment will be described.

[0045] In the method for manufacturing the heat sink 1 of the present embodiment, the heat sink 1 is formed by additive manufacturing (AM). Specifically, the material of the heat sink 1 is prepared, and the heat sink 1 is manufactured by forming the material by additive manufacturing.

[0046] Thereby, the heat sink 1 that can improve the heat dissipation performance can be manufactured relatively easily.

[0047] (4) Modified example Hereinafter, modified examples of the above embodiment will be listed.

[0048] (4.1) Modification 1 As shown in Figure 15, the heat sink 1 of Modification 1 further comprises edge fins 4 separate from the plurality of fins 3.

[0049] The edge fins 4 protrude from the edge 22 of the main surface 21 of the base 2. The height of the edge fins 4 from the base 2 to the tip 41 in the thickness direction D1 is lower than the height of each of the multiple fins 3 from the base 2 to the tip surface 32. The edge fins 4 also have a tapered shape. More specifically, the edge fins 4 are formed so that their height increases from the edge of the main surface 21 of the base 2 towards the inside of the main surface 21 (for example, the central part) to facilitate the intake of air moving upward from below the base 2 into the interior of the heat sink 1 (between the multiple fins 3). In other words, the side surface of the edge fins 4 that faces the edge of the base 2 is inclined to become higher as it approaches the center of the base 2. Preferably, the inclination angle of the side surface of the edge fins 4 that faces the edge of the base 2 is 45° or less.

[0050] This allows air to flow in more easily from below or diagonally below the heatsink 1, for example, thereby further improving the heat dissipation performance of the heatsink 1.

[0051] (4.2) Other Modified Examples The heat sink 1 may have fins other than the plurality of fins 3 and edge fins 4, which are not shown. The fins not shown are, for example, general rectangular plate-shaped fins.

[0052] The tip surface 32 of the second portion 302 of the fin 3 may be anodized, such as black anodizing, or painted black with spray paint. In other words, the fin 3 may be formed such that the emissivity of the tip surface 32 of the fin 3 is higher than the emissivity of the surface of other parts of the fin 3 (for example, the first portion 301). Furthermore, not only the tip surface 32, but a predetermined range of the second portion 302 including the tip surface 32 may be anodized, such as black anodizing, or painted black with spray paint.

[0053] (Aspects) As is clear from the embodiments and modifications described above, the heat sink (1) according to the first aspect comprises a base (2) and a plurality of fins (3). The base (2) has a main surface (21). The shape of the base (2) is flat. The plurality of fins (3) protrude from the main surface (21) of the base (2). Each of the plurality of fins (3) has a first portion (301) and a second portion (302). In the first portion (301), the area of ​​the cross-section perpendicular to the thickness direction (D1) decreases as it moves away from the base (2) in the thickness direction (D1). In the second portion (302), the area of ​​the cross-section perpendicular to the thickness direction (D1) increases as it moves away from the first portion (301) in the thickness direction (D1). The second portion (302) includes a tip surface (32) in the thickness direction (D1).

[0054] According to this embodiment, it is possible to improve heat dissipation performance.

[0055] In the heat sink (1) according to the second embodiment, the plurality of fins (3) in the first embodiment include a first fin (3A) and a second fin (3B). The tip surface (32) of the first fin (3A) and the tip surface (32) of the second fin (3B) are continuous.

[0056] According to this embodiment, it is possible to improve heat dissipation performance.

[0057] In the heat sink (1) according to the third embodiment, in the first or second embodiment, the first portion (301) does not overlap with the edge (22) of the main surface (21) of the base (2) when viewed from the thickness direction (D1).

[0058] According to this embodiment, it is possible to improve heat dissipation performance.

[0059] The heat sink (1) according to the fourth embodiment further comprises, in any of the first to third embodiments, an edge fin (4) separate from the plurality of fins (3). The edge fin (4) protrudes from the edge (22) of the main surface (21) of the base (2). In the edge fin (4), the height from the base (2) to the tip in the thickness direction (D1) is lower than the height from the base (2) to the tip surface (32) of each of the plurality of fins (3). The shape of the edge fin (4) is tapered.

[0060] According to this embodiment, it is possible to improve heat dissipation performance.

[0061] In the heat sink (1) according to the fifth embodiment, in any of the first to fourth embodiments, the cross-section of the second portion (302) widens towards the edge (22) of the main surface (21) of the base (2) as it moves away from the first portion (301) in the thickness direction (D1).

[0062] According to this embodiment, it is possible to improve heat dissipation performance.

[0063] In the heat sink (1) according to the sixth embodiment, in any of the first to fifth embodiments, the tip surface (32) of each of the plurality of fins (3) is anodized or painted black.

[0064] According to this embodiment, it is possible to improve heat dissipation performance.

[0065] Configurations other than those in the first embodiment are not essential to the heatsink (1) and can be omitted as appropriate.

[0066] The seventh embodiment is a method for manufacturing a heat sink (1) in which a heat sink (1) according to any of the first to sixth embodiments is formed by additive manufacturing.

[0067] According to this embodiment, a heat sink (1) capable of improving heat dissipation performance can be manufactured relatively easily.

[0068] 1 Heat sink 2 Base 21 Main surface 22 Edge 3 Fin 3A First fin 3B Second fin 301 First part 302 Second part 32 Front surface 4 Edge fin D1 Thickness direction

Claims

1. A heat sink comprising: a flat base having a main surface; and a plurality of fins protruding from the main surface of the base, wherein each of the plurality of fins has a first portion whose cross-sectional area perpendicular to the thickness direction decreases as it moves away from the base in the thickness direction; and a second portion whose cross-sectional area perpendicular to the thickness direction increases as it moves away from the first portion in the thickness direction, the second portion including a tip surface in the thickness direction.

2. The heat sink according to claim 1, wherein the plurality of fins include a first fin and a second fin, and the tip surface of the first fin and the tip surface of the second fin are continuous.

3. The heat sink according to claim 1, wherein, when viewed from the thickness direction, the first portion does not overlap with the edge of the main surface of the base.

4. The heat sink according to claim 1, further comprising edge fins separate from the plurality of fins, wherein the edge fins protrude from the edge of the main surface of the base, and the height from the base to the tip in the thickness direction is lower than the height from the base to the tip surface of each of the plurality of fins, and the edge fins are tapered in shape.

5. The heat sink according to claim 1, wherein the cross-section of the second portion widens towards the edge of the main surface of the base as it moves away from the first portion in the thickness direction.

6. The heat sink according to claim 1, wherein the tip surface of each of the plurality of fins is anodized or painted black.

7. A method for manufacturing a heat sink, comprising forming the heat sink according to any one of claims 1 to 6 by additive manufacturing.

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