Heat sink, method for manufacturing heat sink and electronic equipment

Abstract

To provide a heat sink which can be improved in cooling efficiency.SOLUTION: A heat sink 1 comprises a solid base portion 10 and a heat sink main body portion 20. The base portion 10 includes a mounting surface 13 on which a heat generating element 5 is placed. The heat sink main body portion 20 is laminated on the base portion 10 on the side opposite to the mounting surface 13. The heat sink main body portion 20 includes a first end surface 21 and a second end surface 22. The heat sink main body portion 20 is provided with a plurality of through-holes 24 through which the coolant 14 can pass. The plurality of through-holes 24 extend from the first end surface 21 to the second end surface 22, and are arranged in a direction away from the mounting surface 13. The plurality of through-holes 24 do not intersect, merge, or branch off from one another.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a heat sink, a method for manufacturing a heat sink, and an electronic device. [Background technology]

[0002] For example, Japanese Patent Laid-Open Publication No. 2005-228948 (Patent Document 1) discloses a heat sink formed by casting. The heat sink in Patent Document 1 includes a base on which a heat generating element is placed, and a number of fins supported by the base. In this heat sink, the heat generating element is cooled by flowing a coolant through through holes formed in the fins. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-228948 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the heat sink disclosed in Patent Document 1, the through holes are formed by a casting method, and therefore the through holes may be branched. When the through holes are branched, the refrigerant merges or branches at the branching points of the through holes, causing a pressure loss of the refrigerant. As a result, there is a problem that sufficient cooling efficiency cannot be obtained. The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide a heat sink capable of improving cooling efficiency, a manufacturing method thereof, and an electronic device. [Means for solving the problem]

[0005] The heat sink of the present disclosure includes a solid base portion and a heat sink main body portion. The base portion includes a mounting surface on which a heat generating element is placed. The heat sink main body portion is laminated to the base portion on the side opposite the mounting surface. The heat sink main body portion includes a first end surface and a second end surface opposite the first end surface. The heat sink main body portion is provided with a plurality of through holes through which a coolant can pass. The plurality of through holes extend from the first end surface to the second end surface and are arranged in a direction away from the mounting surface. The plurality of through holes do not intersect, merge, or branch off from one another.

[0006] A method of manufacturing the heat sink of the present disclosure includes forming a base portion and forming a heat sink body portion by a three-dimensional additive manufacturing process.

[0007] The electronic device of the present disclosure includes the heat sink of the present disclosure and an electronic device that is placed on the placement surface and is a heat generating body. Effect of the Invention

[0008] According to the present disclosure, the pressure loss of the coolant in the multiple through holes can be reduced, and as a result, the cooling efficiency of the heat sink can be improved. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic perspective view of a heat sink according to a first embodiment. [Diagram 2] 2 is a schematic cross-sectional view of the heat sink according to the first embodiment taken along the cross-sectional line II-II shown in FIG. [Diagram 3] 2 is a schematic rear view of the heat sink according to the first embodiment. FIG. [Figure 4] FIG. 11 is a schematic front view of a heat sink according to a modified example of the first embodiment. [Diagram 5] FIG. 3 is a flowchart showing a method for manufacturing the heat sink according to the first embodiment. [Figure 6] 3 is a schematic diagram showing a step of a method for manufacturing the heat sink according to the first embodiment. FIG. [Figure 7] 7 is a schematic view showing a step subsequent to the step shown in FIG. 6 in the method of manufacturing the heat sink according to the first embodiment. [Figure 8] FIG. 2 is a schematic cross-sectional view of a heat sink of a first comparative example. [Figure 9] FIG. 11 is a schematic cross-sectional view of a heat sink of a second comparative example. [Figure 10] FIG. 11 is a schematic perspective view of a heat sink according to a second embodiment. [Figure 11] 11 is a schematic cross-sectional view of the heat sink according to the second embodiment taken along the cross-sectional line XI-XI shown in FIG. [Figure 12] FIG. 11 is a schematic perspective view of a heat sink according to a first modified example of the second embodiment. [Figure 13] 13 is a schematic cross-sectional view of a heat sink according to a first modified example of the second embodiment, taken along the cross-sectional line XIII-XIII shown in FIG. 12. [Figure 14] FIG. 11 is a schematic perspective view of a heat sink according to a second modified example of the second embodiment. [Figure 15] FIG. 11 is a schematic perspective view of a heat sink according to a third embodiment. [Figure 16] 16 is a schematic cross-sectional view of the heat sink according to the third embodiment taken along the cross-sectional line XVI-XVI shown in FIG. 15. [Figure 17] FIG. 11 is a schematic perspective view of a heat sink according to a fourth embodiment. [Figure 18] 18 is a schematic cross-sectional view of the heat sink according to the fourth embodiment taken along the cross-sectional line XVIII-XVIII shown in FIG. 17. [Figure 19] 18 is a schematic cross-sectional view of the heat sink according to the fourth embodiment taken along the cross-sectional line XIX-XIX shown in FIG. 17. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described. Note that the same reference numerals are used to refer to the same components, and the description thereof will not be repeated.

[0011] Embodiment 1

[0012] A heat sink 1 according to a first embodiment will be described with reference to Fig. 1 to Fig. 4. As shown in Fig. 1 and Fig. 2, the heat sink 1 is disposed, for example, in a duct 8 through which a coolant 14 flows. The coolant 14 is, for example, a liquid such as an antifreeze liquid (e.g., an ethylene glycol aqueous solution) or water, or a gas such as air. The heat sink 1 includes a base portion 10 and a heat sink main body portion 20.

[0013] The base portion 10 includes an end face 11 , an end face 12 opposite to the end face 11 , a mounting face 13 , a side face 15 , and a side face 16 opposite to the side face 15 . In addition, in Fig. 1, the directions along the mounting surface 13 are the x-axis direction and the y-axis direction. That is, the horizontal direction in Fig. 1 is the x-axis direction, the up-down direction in Fig. 1 is the z-axis direction, and the x-axis, y-axis, and z-axis are perpendicular to each other.

[0014] The end face 11 and the end face 12 are spaced apart from each other in the direction in which the through holes 24 extend (y direction), i.e., in the direction in which the coolant 14 flows. The end face 11 and the end face 12 are, for example, both end faces of the base part 10 in the direction in which the coolant 14 flows. The end face 11 is, for example, the end face of the base part 10 on the inflow side of the coolant 14. The end face 12 is, for example, the end face of the base part 10 on the outflow side of the coolant 14. The end face 11 and the end face 12 are, for example, surfaces perpendicular to the direction in which the through holes 24 extend. That is, the end face 11 and the end face 12 are, for example, surfaces parallel to the xz plane, and extend in the x direction and the z direction. The mounting face 13 is connected to the end face 11 and the end face 12. The heating element 5 is mounted on the mounting face 13.

[0015] The base portion 10 is solid. The base portion 10 does not have a through hole, a blind hole, or a slit. Therefore, the base portion 10 can efficiently spread the heat from the heating element 5 throughout the entire base portion 10. The thickness t of the base portion 10 is 1 is, for example, 1 mm or more and 10 mm or less.

[0016] The base portion 10 is formed of a material having high thermal conductivity. The base portion 10 is formed of a metal such as copper (Cu) or aluminum (Al). The base portion 10 is formed by a three-dimensional additive manufacturing method such as a powder bed process, a directed energy deposition process, a fused deposition modeling process, or a binder jet process.

[0017] The heat sink body 20 is laminated on the base portion 10 on the side opposite to the mounting surface 13. The heat sink body 20 may be integrally formed with the base portion 10.

[0018] The heat sink main body 20 includes a first end face 21, a second end face 22 opposite to the first end face 21, a first face 23a, a second face 23b opposite to the first face 23a, and a third face 23c opposite to the mounting face 13. The first end face 21 and the second end face 22 are spaced apart from each other in the direction in which the through holes 24 extend (y direction), that is, in the direction in which the refrigerant 14 flows (y direction). The first end face 21 and the second end face 22 are, for example, both end faces of the heat sink main body 20 in the direction in which the refrigerant 14 flows. The first end face 21 is, for example, an end face of the heat sink main body 20 on the inflow side of the refrigerant 14, and is connected to the end face 11 of the base part 10. The second end face 22 is, for example, an end face of the heat sink main body 20 on the outflow side of the refrigerant 14, and is connected to the end face 12 of the base part 10. The first end face 21 may be flush with the end face 11. The second end face 22 may be flush with the end face 12. The first end face 21 and the second end face 22 are each, for example, a surface perpendicular to the direction in which the multiple through holes 24 extend. That is, the first end face 21 and the second end face 22 are each a surface parallel to the xz plane and extend in the x direction and the z direction.

[0019] The heat sink body 20 is formed of a material having high thermal conductivity. The heat sink body 20 is formed of a metal such as copper (Cu) or aluminum (Al). The heat sink body 20 may be formed of the same material as the base portion 10. The thickness t of the heat sink body 20 is 2 is the thickness t of the base portion 10 1The thickness t of the heat sink body 20 is larger than 2 is, for example, 1.5 mm or more and 100 mm or less. The heat sink main body 20 is, for example, a metal block. The heat sink main body 20 is formed by a three-dimensional additive manufacturing method such as a powder bed process, a directed energy deposition process, a fused deposition modeling process, or a binder jet process.

[0020] The heat sink body 20 is provided with a plurality of through holes 24 through which the refrigerant 14 can pass. The plurality of through holes 24 extend from the first end surface 21 to the second end surface 22. The heat sink body 20 is not provided with blind holes, cavities, or slits. In this specification, the blind hole means a hole in which one end of the hole is connected to the external space of the heat sink 1 and the other end of the hole is closed, such as the blind hole 27 shown in FIG. 8. In this specification, the cavity means a closed hole separated from the external space of the heat sink 1, such as the cavities 18 and 26 shown in FIG. 8 and FIG. 9. The slits are formed in the cross-sectional direction of the through hole 24, and are formed at predetermined intervals in the direction in which the refrigerant 14 flows to form fins. The heat sink body 20 is provided with only a plurality of through holes 24. The plurality of through holes 24 are, for example, straight through holes. The plurality of through holes 24 do not intersect, merge, or branch off from each other.

[0021] The multiple through holes 24 are arranged in a direction away from the mounting surface 13 (-z direction). For example, as shown in Figs. 1 and 3, the multiple through holes 24 are arranged in a staggered pattern. As shown in Fig. 4, the multiple through holes 24 may be arranged in a square lattice pattern. In a plan view of the mounting surface 13, the mounting surface 13 overlaps the multiple through holes 24. The multiple through holes 24 are arranged below the mounting surface 13.

[0022] The ratio of the area of ​​the through holes 24 in the first end face 21 (the sum of the cross-sectional areas of the through holes 24) to the area of ​​the first end face 21 (including the area of ​​the through holes 24) is, for example, 20% or more. The ratio of the area of ​​the through holes 24 in the second end face 22 to the area of ​​the second end face 22 is, for example, 20% or more. The diameter d of each of the through holes 24 is, for example, 1 mm or more. The interval g between two adjacent through holes 24 among the through holes 24 is, for example, 0.5 mm or more. Therefore, when the heat sink 1 is manufactured by a three-dimensional additive manufacturing method, the through holes 24 can be prevented from being clogged with metal powder 37 (see FIGS. 6 and 7).

[0023] 1 and 2, an electronic device 2 of the present embodiment includes a heat sink 1, an electronic device 6, and a duct 8. The electronic device 6 is placed on a placement surface 13 and is a heat generating body 5. The electronic device 6 is not particularly limited, but is, for example, a power semiconductor element, an antenna element, or an antenna transceiver module. The duct 8 defines a flow path of a coolant 14. The coolant 14 flows through the duct 8. The duct 8 is provided with an opening 9. The heat sink 1 is fitted into the opening 9.

[0024] An example of a method for manufacturing the heat sink 1 of this embodiment by a 3D printer will be described with reference to Fig. 5 to Fig. 7. The heat sink 1 is manufactured by, for example, a three-dimensional additive manufacturing method. With reference to Figs. 6 and 7, a three-dimensional additive manufacturing apparatus 30 used in a powder bed type three-dimensional additive manufacturing method, which is one of the three-dimensional additive manufacturing methods, mainly includes a laser light source 31, an optical scanning device 33, a movable table 34, a plate 35, a tank 36 that stores metal powder 37, a stage 38, and a squeegee 39.

[0025] 5 and 6, a method for manufacturing the heat sink 1 of the present embodiment includes forming (S1) the base portion 10. The base portion 10 is formed by, for example, a three-dimensional additive manufacturing method.

[0026] Specifically, a plate 35 is placed on a movable table 34. An opening 35a is provided in the plate 35. Metal powder 37 is supplied from a tank 36 onto a stage 38. The metal powder 37 on the stage 38 is spread in the opening 35a of the plate 35 using a squeegee 39. The laser light source 31 emits a laser beam 32. The optical scanning device 33 scans the laser beam 32 toward the metal powder 37 in the opening 35a of the plate 35. The laser beam 32 scanned by the optical scanning device 33 is irradiated onto the metal powder 37 in the opening 35a of the plate 35. The metal powder 37 is melted by irradiation with the laser beam 32, and solidifies after irradiation with the laser beam 32. In this manner, the base portion 10 is formed.

[0027] 5 and 7, the method for manufacturing the heat sink 1 of the present embodiment includes forming (S2) the heat sink main body 20. The heat sink main body 20 is formed by, for example, a three-dimensional additive manufacturing method.

[0028] Specifically, a plate 35 is placed on another plate 35. An opening 35a is provided in the plate 35. Metal powder 37 is supplied from a tank 36 onto a stage 38. The metal powder 37 on the stage 38 is spread in the opening 35a of the plate 35 using a squeegee 39. The laser light source 31 emits a laser beam 32. The optical scanning device 33 scans the laser beam 32 toward the metal powder 37 in the opening 35a of the plate 35. The laser beam 32 scanned by the optical scanning device 33 is irradiated onto the metal powder 37 in the opening 35a of the plate 35. The metal powder 37 melts when irradiated with the laser beam 32, and solidifies after irradiation with the laser beam 32. The steps from placing the other plate 35 to irradiating the metal powder 37 with the laser beam 32 are repeated. In this manner, the heat sink main body 20 having a plurality of through holes 24 is formed.

[0029] In this embodiment, the heat sink main body 20 is formed after the base 10, but the base 10 may be formed after the heat sink main body 20. The three-dimensional additive manufacturing method is not limited to the powder bed method, and may be a directed energy deposition method, a fused deposition model method, a binder jet method, or the like.

[0030] The operation of the heat sink 1 of this embodiment will be described while comparing it with a heat sink 1a of a first comparative example and a heat sink 1b of a second comparative example.

[0031] 8, the heat sink 1a of the first comparative example is manufactured by a casting method. Therefore, as shown in Fig. 8, a cavity 18 is formed inside the base portion 10. In addition to the through hole 24, a cavity 26 and a blind hole 27 are formed in the heat sink main body 20.

[0032] When the cavities 18, 26 are formed inside the heat sink 1a, the thermal resistance of the heat sink 1a increases. The cooling efficiency of the heat sink 1a decreases. Furthermore, when the cavities 18, 26 are formed inside the heat sink 1a, the rigidity of the heat sink 1a decreases, and the vibration resistance of the heat sink 1a decreases. Therefore, when the heat sink 1a is used in a vibration environment, the heat sink 1a may vibrate, causing the position of the heating element 5 relative to the heat sink 1a to shift, or the heat sink 1a may be damaged.

[0033] Furthermore, when the blind holes 27 are formed in the heat sink body 20, a pressure loss occurs in the coolant 14 at the blind holes 27. This reduces the cooling efficiency of the heat sink 1a.

[0034] 9, in order to eliminate the cavity 26 and the blind hole 27 in the heat sink 1a of the first comparative example, in the heat sink 1b of the second comparative example, a slit 29 is formed between the first end face 21 and the second end face 22. The slit 29 is connected to the cavity 26 and the blind hole 27, and the cavity 26 and the blind hole 27 become the through hole 24.

[0035] However, the cavity 18 remains in the base portion 10. Therefore, the thermal resistance of the heat sink 1b increases. In addition, in the heat sink 1b, the multiple through holes 24 intersect, merge, or branch, so the pressure loss of the refrigerant 14 in the multiple through holes 24 is high. Therefore, the cooling efficiency of the heat sink 1b decreases. In addition, the cavity 18 remains in the base portion 10, and the slit 29 is formed in the heat sink main body portion 20. Therefore, the rigidity of the heat sink 1b decreases, and the vibration resistance of the heat sink 1b decreases. When the heat sink 1b is used in a vibration environment, the heat sink 1b may vibrate, causing the position of the heating element 5 relative to the heat sink 1b to shift, or the heat sink 1b may be damaged.

[0036] In contrast, in the heat sink 1 of this embodiment, the base portion 10 is solid, and no blind holes or cavities are formed in the base portion 10 as in heat sinks manufactured by casting. Since the base portion 10 is thinner than the heat sink main body 20, the rigidity of the base portion 10 decreases if there are blind holes or cavities in the base portion 10. However, no blind holes or cavities are formed in the base portion 10 of the heat sink 1 of this embodiment. Therefore, the rigidity of the base portion 10 can be sufficiently ensured. Furthermore, since there is no reduction in the heat dissipation area due to blind holes and cavities, the cooling efficiency of the heat sink 1 can be improved. Moreover, no blind holes, cavities, or slits are formed in the heat sink main body 20. Since blind holes, cavities, and slits have a lower heat dissipation effect than the through holes 24, providing a plurality of through holes 24 in the heat sink main body 20 instead of the blind holes, cavities, and slits can dissipate heat from the heat generating element 5 more efficiently. Since no blind holes, cavities, or slits are provided in the heat sink main body 20 of this embodiment, a plurality of through holes 24 can be efficiently formed in the heat sink main body 20. Therefore, the cooling efficiency of the heat sink 1 can be improved. Furthermore, the through holes 24 do not intersect, merge, or branch off from one another, which reduces the pressure loss of the coolant 14 in the through holes 24. As a result, the cooling efficiency of the heat sink 1 is improved.

[0037] The effects of the heat sink 1, the method for manufacturing the heat sink 1, and the electronic device 2 of the present embodiment will be described.

[0038] The heat sink 1 of this embodiment includes a solid base portion 10 and a heat sink main body portion 20. The base portion 10 includes a mounting surface 13 on which a heat generating element 5 is placed. The heat sink main body portion 20 is laminated on the base portion 10 on the side opposite to the mounting surface 13. The heat sink main body portion 20 includes a first end surface 21 and a second end surface 22 opposite to the first end surface 21. The heat sink main body portion 20 is provided with a plurality of through holes 24 through which the refrigerant 14 can pass. The plurality of through holes 24 extend from the first end surface 21 to the second end surface 22, and are arranged in a direction away from the mounting surface 13. The plurality of through holes 24 do not intersect, merge, or branch off from one another.

[0039] Therefore, when the refrigerant 14 flows through the through holes 24, the thermal resistance of the heat sink 1 decreases. Also, the pressure loss of the refrigerant 14 in the through holes 24 decreases. As a result, the cooling efficiency of the heat sink 1 improves. Also, since the rigidity of the heat sink 1 improves, the vibration resistance of the heat sink 1 improves. Even if the heat sink 1 is used in a vibration environment, the position of the heating element 5 relative to the heat sink 1 is prevented from shifting and the heat sink 1 is prevented from being damaged.

[0040] In the heat sink 1 of this embodiment, the heat sink body 20 is not formed with any blind holes, cavities, or slits.

[0041] Therefore, when the coolant 14 flows through the through holes 24, the thermal resistance of the heat sink 1 decreases. Also, the pressure loss of the coolant 14 in the through holes 24 decreases. As a result, the cooling efficiency of the heat sink 1 improves. Also, the rigidity of the heat sink 1 improves, and therefore the vibration resistance of the heat sink 1 improves.

[0042] In the heat sink 1 of this embodiment, the heat sink body 20 is provided with only a plurality of through holes 24.

[0043] Therefore, when the coolant 14 flows through the through holes 24, the thermal resistance of the heat sink 1 decreases. Also, the pressure loss of the coolant 14 in the through holes 24 decreases. As a result, the cooling efficiency of the heat sink 1 improves. Also, the rigidity of the heat sink 1 improves, and therefore the vibration resistance of the heat sink 1 improves.

[0044] In the heat sink 1 of this embodiment, the heat sink body 20 is integrally formed with the base portion 10.

[0045] Therefore, the base portion 10 and the heat sink body portion 20 can be formed continuously. The heat sink 1 can be manufactured in a shorter time. The cost of the heat sink 1 is reduced.

[0046] In the heat sink 1 of this embodiment, the heat sink body 20 is formed from the same material as the base portion 10.

[0047] The heat sink 1 can be manufactured using fewer types of materials, thus reducing the cost of the heat sink 1.

[0048] In the heat sink 1 of the present embodiment, the plurality of through holes 24 are straight through holes.

[0049] Therefore, when the coolant 14 flows through the plurality of through holes 24, the pressure loss of the coolant 14 in the plurality of through holes 24 is reduced, and the cooling efficiency of the heat sink 1 is improved.

[0050] In the heat sink 1 of the present embodiment, the multiple through holes 24 are arranged in a staggered pattern.

[0051] The staggered arrangement of the through holes 24 allows the number of through holes 24 provided in the first end face 21 and the second end face 22 to be increased compared to the arrangement of the through holes 24 in a square lattice pattern. This increases the contact area between the refrigerant 14 flowing through the through holes 24 and the heat sink main body 20. In addition, the flow rate of the refrigerant 14 in each of the through holes 24 decreases, reducing the pressure loss of the refrigerant in the through holes 24. As a result, the cooling efficiency of the heat sink 1 is improved.

[0052] The method for manufacturing the heat sink 1 of the present embodiment includes forming the base portion 10 (S1) and forming the heat sink main body portion 20 by three-dimensional additive manufacturing (S2).

[0053] Therefore, the heat sink body 20 without blind holes, cavities, and slits can be easily manufactured. In addition, even if the aspect ratio of the through holes 24 is large, the through holes 24 can be easily formed in the heat sink body 20. When the aspect ratio of each of the through holes 24 is large, the contact area between the refrigerant 14 flowing through the through holes 24 and the heat sink body 20 increases. Therefore, the heat sink 1 with improved cooling efficiency can be easily manufactured. In this specification, the aspect ratio of each of the through holes 24 means, for example, the ratio of the longitudinal length of each of the through holes 24 to the diameter of each of the through holes 24.

[0054] In the method for manufacturing the heat sink 1 of this embodiment, the base portion 10 is formed by a three-dimensional additive manufacturing method.

[0055] Therefore, it is possible to easily form a solid base portion 10. Therefore, the thermal resistance of the heat sink 1 is reduced. Also, the rigidity of the heat sink 1 is improved. It is possible to easily manufacture the heat sink 1 having improved cooling efficiency and improved vibration resistance.

[0056] In this embodiment, the heat sink 1 having the plurality of through holes 24 is manufactured by a 3D printer, so that a heat pipe having the plurality of through holes 24 with a small diameter and linearity that cannot be formed by machining can be formed. As a result, a heat pipe having a high thermal conductivity is obtained, and a heat sink 1 with high cooling efficiency can be formed. A plurality of through holes 24 having a more uniform diameter and longer can be formed in the heat sink main body 20 at low cost.

[0057] The electronic device 2 of this embodiment includes the heat sink 1 of this embodiment and an electronic device 6. The electronic device 6 is placed on the placement surface 13 and is a heat generating body 5.

[0058] Since the electronic device 2 is provided with the heat sink 1, it has improved cooling efficiency and improved vibration resistance.

[0059] Embodiment 2

[0060] A heat sink 1 according to a second embodiment will be described with reference to Figures 10 and 11. The heat sink 1 of this embodiment has a similar configuration to the heat sink 1 of the first embodiment, but differs mainly in the following respects.

[0061] In this embodiment, the cross-sectional area of ​​the multiple through holes 24 decreases with increasing distance from the mounting surface 13. In this specification, the cross-sectional area of ​​the through holes 24 means the cross-sectional area of ​​a cross section perpendicular to the longitudinal direction (y direction) of the through holes 24. The cross-sectional area of ​​the through holes 24 may be, for example, the area of ​​the through holes 24 at the first end face 21 or the area of ​​the through holes 24 at the second end face 22. Therefore, the cooling efficiency of the heat sink 1 is improved for the following reasons.

[0062] When the refrigerant 14 flows through the through hole 24, a velocity boundary layer of the refrigerant 14 is formed on the surface of the heat sink main body 20 that defines the through hole 24. The thickness of the velocity boundary layer decreases as the cross-sectional area of ​​the through hole 24 decreases. On the other hand, due to the difference between the temperature of the heat sink main body 20 and the temperature of the refrigerant 14, a temperature boundary layer is formed on the surface of the heat sink main body 20 that defines the through hole 24. The thickness of the velocity boundary layer decreases as the thickness of the temperature boundary layer decreases. When the thickness of the temperature boundary layer decreases, the heat transfer coefficient from the surface of the heat sink main body 20 that defines the through hole 24 to the refrigerant 14 increases. Therefore, when the cross-sectional area of ​​the through hole 24 decreases, the heat transfer coefficient from the surface of the heat sink main body 20 that defines the through hole 24 to the refrigerant 14 increases. In this embodiment, the heat transfer coefficient from the surface of the heat sink main body 20 that defines the multiple through holes 24 to the refrigerant 14 increases as it moves away from the mounting surface 13.

[0063] The temperature of the heat sink main body 20 decreases with increasing distance from the mounting surface 13 on which the heating element 5 is placed. Therefore, the difference between the temperature of the surface of the heat sink main body 20 that defines the multiple through holes 24 and the temperature of the refrigerant 14 decreases with increasing distance from the mounting surface 13.

[0064] In general, when the product of the heat transfer coefficient from the surface of the heat sink main body 20 that defines the multiple through holes 24 to the refrigerant 14 and the difference between the temperature of the surface of the heat sink main body 20 that defines the multiple through holes 24 and the temperature of the refrigerant 14 increases, the amount of heat dissipated from the heat sink main body 20 to the refrigerant 14 increases. As the distance from the mounting surface 13 increases, the difference between the temperature of the surface of the heat sink main body 20 that defines the multiple through holes 24 and the temperature of the refrigerant 14 decreases, but in this embodiment, the heat transfer coefficient from the surface of the heat sink main body 20 that defines the multiple through holes 24 to the refrigerant 14 increases as the distance from the mounting surface 13 increases. Therefore, even in the part of the heat sink main body 20 that is far from the mounting surface 13, heat can be efficiently dissipated from the surface of the heat sink main body 20 that defines the multiple through holes 24 to the refrigerant 14. Therefore, the cooling efficiency of the heat sink 1 is improved.

[0065] 12 and 13, in the first modification of the present embodiment, the cross-sectional area of ​​the plurality of through holes 24 increases with increasing distance from the mounting surface 13. Therefore, for the following reason, the refrigerant 14 can flow more reliably through the plurality of through holes 24.

[0066] If the cross-sectional areas of all the through holes 24 are reduced in order to maximize the heat transfer coefficient from the surface of the heat sink main body 20 that defines the through holes 24 to the refrigerant 14, the through holes 24 may become clogged with metal powder 37 (see FIGS. 6 and 7) discharged from the three-dimensional additive manufacturing device. If the through holes 24 become clogged, the refrigerant 14 cannot flow through the through holes 24, and the heating element 5 cannot be cooled. However, in the first modified example of this embodiment, the cross-sectional areas of the through holes 24 increase with increasing distance from the mounting surface 13. Therefore, clogging of all the through holes 24 is prevented. In this way, the refrigerant 14 can be more reliably flowed through at least some of the through holes 24.

[0067] 14, in heat sink 1 of the second modified example of this embodiment, the cross-sectional area of ​​the plurality of through holes 24 varies in the direction (x direction) along mounting surface 13 of first end face 21. Therefore, when heat generating body 5 has a temperature distribution in the above direction (x direction), heat sink 1 of the second modified example of this embodiment can efficiently cool heat generating body 5.

[0068] For example, in FIG. 14, the heat generating element 5 has a temperature distribution in which the temperature of the heat generating element 5 increases toward the -x direction and decreases toward the +x direction. As already described, as the cross-sectional area of ​​the plurality of through holes 24 decreases, the heat transfer coefficient from the surface of the heat sink main body 20 that defines the plurality of through holes 24 to the refrigerant 14 increases. In the second modification of this embodiment, the through holes 24 with a higher heat transfer coefficient are arranged in correspondence with the portion of the heat generating element 5 having a higher temperature. The through holes 24 with a lower heat transfer coefficient are arranged in correspondence with the portion of the heat generating element 5 having a lower temperature. Therefore, when the heat generating element 5 has the above temperature distribution, the heat sink 1 of the second modification of this embodiment can efficiently cool the heat generating element 5.

[0069] The electronic device 2 of the present embodiment has a similar configuration to the electronic device 2 of the embodiment 1, but instead of the heat sink 1 of the embodiment 1, it has the heat sink 1 of the present embodiment, the heat sink 1 of the first variant of the present embodiment, or the heat sink 1 of the second variant of the present embodiment.

[0070] The effects of the heat sink 1 of this embodiment will be described.

[0071] In the heat sink 1 of this embodiment, multiple through holes 24 are provided in a direction away from the mounting surface 13, i.e., in the -z direction in Figures 10 and 11, and the cross-sectional area of ​​the multiple through holes 24 decreases as the distance from the mounting surface 13 increases.

[0072] Therefore, even in a portion of the heatsink body 20 far from the mounting surface 13, heat can be efficiently dissipated from the surface of the heatsink body 20 that defines the multiple through holes 24 to the refrigerant 14. The cooling efficiency of the heatsink 1 is improved.

[0073] In the heat sink 1 of the present embodiment, the cross-sectional area of ​​the plurality of through holes 24 increases with increasing distance from the mounting surface 13.

[0074] This prevents clogging of all of the through holes 24. The refrigerant 14 can flow through at least some of the through holes 24 more reliably.

[0075] In the heat sink 1 of the present embodiment, the cross-sectional area of ​​the plurality of through holes 24 changes in the direction along the mounting surface 13 of the first end surface 21.

[0076] Therefore, when the heat generating element 5 has a temperature distribution in the above-mentioned direction, the heat sink 1 can efficiently cool the heat generating element 5.

[0077] Embodiment 3

[0078] A heat sink 1 according to a third embodiment will be described with reference to Figures 15 and 16. The heat sink 1 of this embodiment has a similar configuration to the heat sink 1 of the first embodiment, but differs mainly in the following respects.

[0079] In the heat sink 1 of this embodiment, the end faces 11, 12 are inclined with respect to the mounting surface 13 so that the end faces 11, 12 protrude as they approach the mounting surface 13. Therefore, the size of the base portion 10 increases in the direction in which the end faces 11 and 12 are spaced apart from each other (the y direction). The base portion 10 can further spread the heat from the heat generating body 5. The cooling efficiency of the heat sink 1 is improved.

[0080] The first end face 21 and the second end face 22 are inclined with respect to the mounting surface 13 so that the first end face 21 and the second end face 22 protrude toward the mounting surface 13. Therefore, the size of the heat sink main body 20 increases in the direction (y direction) in which the first end face 21 and the second end face 22 are spaced apart from each other. The heat sink main body 20 can further spread the heat from the heat generating element 5. In addition, the contact area between the coolant 14 flowing through the multiple through holes 24 and the heat sink main body 20 increases. The cooling efficiency of the heat sink 1 is improved.

[0081] The electronic device 2 of the present embodiment has a similar configuration to the electronic device 2 of the first embodiment, but instead of the heat sink 1 of the first embodiment, it has the heat sink 1 of the present embodiment.

[0082] The effects of the heat sink 1 of this embodiment will be described.

[0083] In the heat sink 1 of the present embodiment, the first end face 21 is inclined with respect to the mounting surface 13 so that the first end face 21 protrudes more as it approaches the mounting surface 13.

[0084] The size of the heat sink main body 20 increases in the direction (y direction) in which the first end face 21 and the second end face 22 are spaced apart from each other. The heat sink main body 20 can further spread the heat from the heat generating body 5. In addition, the contact area between the coolant 14 flowing through the multiple through holes 24 and the heat sink main body 20 increases. As a result, the cooling efficiency of the heat sink 1 improves.

[0085] Embodiment 4

[0086] A heat sink 1 according to embodiment 4 will be described with reference to Figures 17 to 19. The heat sink 1 of this embodiment has a similar configuration to the heat sink 1 of embodiment 1, but differs mainly in the following respects.

[0087] In the heat sink 1 of this embodiment, the mounting surface 13 includes a first mounting area 13a on which the electronic device 6 is mounted, and a second mounting area 13b on which the electronic device 6b is mounted. The second mounting area 13b is disposed with respect to the first mounting area 13a in a direction intersecting the direction in which the through holes 24 extend (y direction) and the direction in which the base portion 10 and the heat sink main body portion 20 are stacked (z direction) (for example, the x direction perpendicular to these directions).

[0088] The through holes 24 include a plurality of first through holes 24a and a plurality of second through holes 24b. The plurality of first through holes 24a are arranged on the opposite side of the first mounting area 13a with respect to the base portion 10. In a plan view of the mounting surface 13, the first mounting area 13a overlaps with the plurality of first through holes 24a. The plurality of first through holes 24a are arranged below the first mounting area 13a. The plurality of second through holes 24b are arranged on the opposite side of the second mounting area 13b with respect to the base portion 10. In a plan view of the mounting surface 13, the second mounting area 13b overlaps with the plurality of second through holes 24b. The plurality of second through holes 24b are arranged below the second mounting area 13b.

[0089] The first cross-sectional area of ​​each of the plurality of first through holes 24a is different from the second cross-sectional area of ​​each of the plurality of second through holes 24b. For example, the first cross-sectional area of ​​each of the plurality of first through holes 24a is smaller than the second cross-sectional area of ​​each of the plurality of second through holes 24b. The diameter of each of the plurality of first through holes 24a is smaller than the diameter of each of the plurality of second through holes 24b. Therefore, the heat transfer coefficient of each of the plurality of first through holes 24a is larger than the heat transfer coefficient of each of the plurality of second through holes 24b.

[0090] The electronic device 2 of the present embodiment has a similar configuration to the electronic device 2 of the first embodiment, but differs from the electronic device 2 of the first embodiment in the following points.

[0091] The electronic device 2 of the present embodiment includes the heat sink 1 of the present embodiment instead of the heat sink 1 of the first embodiment.

[0092] In the electronic device 2 of the present embodiment, the heat generating element 5 includes an electronic device 6 and an electronic device 6b. The electronic device 6b is not particularly limited, but may be, for example, a power semiconductor element, an antenna element, or an antenna transmission / reception module.

[0093] The electronic device 6 is placed on the first mounting area 13a. In a plan view of the mounting surface 13, the electronic device 6 overlaps with the multiple first through holes 24a. The multiple first through holes 24a are arranged below the electronic device 6. The electronic device 6b is placed on the second mounting area 13b. In a plan view of the mounting surface 13, the electronic device 6b overlaps with the multiple second through holes 24b. The multiple second through holes 24b are arranged below the electronic device 6b. The electronic device 6 generates a larger amount of heat than the electronic device 6b.

[0094] As already described, when the cross-sectional area of ​​the plurality of through holes 24 is reduced, the heat transfer coefficient from the surface of the heat sink main body 20 that defines the plurality of through holes 24 to the refrigerant 14 is increased. In this embodiment, the plurality of first through holes 24a having a higher heat transfer coefficient are arranged for the electronic device 6 having a larger amount of heat generation among the electronic devices 6, 6b. The plurality of second through holes 24b having a lower heat transfer coefficient are arranged for the electronic device 6b having a smaller amount of heat generation among the electronic devices 6, 6b. Therefore, the electronic device 6 and the electronic device 6b can be efficiently cooled.

[0095] The effects of the heat sink 1 and the electronic device 2 of this embodiment will be described.

[0096] In the heat sink 1 of this embodiment, the mounting surface 13 includes a first mounting region 13a and a second mounting region 13b. The multiple through holes 24 include a multiple first through holes 24a and a multiple second through holes 24b. The multiple first through holes 24a are arranged on the opposite side of the base portion 10 from the first mounting region 13a. The multiple second through holes 24b are arranged on the opposite side of the base portion 10 from the second mounting region 13b. The first cross-sectional area of ​​each of the multiple first through holes 24a is different from the second cross-sectional area of ​​each of the multiple second through holes 24b.

[0097] Therefore, when the heat generating body 5 has a temperature distribution, the heat sink 1 can efficiently cool the heat generating body 5. Also, when the heat generating body 5 includes a plurality of electronic devices 6, 6b having different amounts of heat generation, the heat sink 1 can efficiently cool the plurality of electronic devices 6, 6b.

[0098] In the electronic device 2 of the present embodiment, the heat generating body 5 includes a first electronic device (electronic device 6) placed on the first mounting area 13a and a second electronic device (electronic device 6b) placed on the second mounting area 13b. The first electronic device has a larger amount of heat generation than the second electronic device. The first cross-sectional area of ​​each of the multiple first through holes 24a is smaller than the second cross-sectional area of ​​each of the multiple second through holes 24b.

[0099] A plurality of first through-holes 24a having a higher thermal conductivity are arranged for the first electronic device (electronic device 6) which generates a larger amount of heat than the second electronic device (electronic device 6b). A plurality of second through-holes 24b having a lower thermal conductivity are arranged for the second electronic device which generates a smaller amount of heat than the first electronic device. This allows the first electronic device and the second electronic device to be efficiently cooled.

[0100] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) a solid base portion including a mounting surface on which the heating element is placed; a heat sink main body portion laminated on the base portion on the side opposite to the mounting surface, The heat sink body includes a first end surface and a second end surface opposite the first end surface, The heat sink body is provided with a plurality of through holes through which a coolant can pass, the plurality of through holes extend from the first end surface to the second end surface and are arranged in a direction away from the mounting surface, A heat sink, wherein the plurality of through holes do not intersect, merge or branch off from one another. (Appendix 2) 2. The heat sink of claim 1, wherein the heat sink body does not have blind holes, cavities, or slits formed therein. (Appendix 3) The heat sink according to claim 1 or 2, wherein only the plurality of through holes are provided in the heat sink main body. (Appendix 4) 4. The heat sink according to claim 1, wherein the heat sink body is integrally formed with the base. (Appendix 5) 5. The heat sink of claim 1, wherein the heat sink body is formed from the same material as the base. (Appendix 6) 6. The heat sink of claim 1, wherein the plurality of through holes are straight through holes. (Appendix 7) 7. The heat sink according to claim 1, wherein the through holes are arranged in a staggered pattern. (Appendix 8) 8. The heat sink of claim 1, wherein a cross-sectional area of ​​the plurality of through holes decreases with increasing distance from the mounting surface. (Appendix 9) 8. The heat sink of claim 1, wherein a cross-sectional area of ​​the plurality of through holes increases with increasing distance from the mounting surface. (Appendix 10) 8. The heat sink according to claim 1, wherein a cross-sectional area of ​​the plurality of through holes varies in a direction along the mounting surface of the first end face. (Appendix 11) 11. The heat sink of claim 1, wherein the first end surface is inclined with respect to the mounting surface so that the first end surface protrudes toward the mounting surface. (Appendix 12) The mounting surface includes a first mounting area and a second mounting area, The plurality of through holes includes a plurality of first through holes and a plurality of second through holes, the first through holes are disposed on an opposite side of the base portion from the first mounting area, the second through holes are disposed on an opposite side of the base portion from the second mounting area, 12. The heat sink of any one of claims 1 to 11, wherein a first cross-sectional area of ​​each of the plurality of first through holes is different from a second cross-sectional area of ​​each of the plurality of second through holes. (Appendix 13) 13. A method for manufacturing the heat sink according to any one of claims 1 to 12, comprising the steps of: forming the base portion; and forming the heat sink body by three-dimensional additive manufacturing. (Appendix 14) 14. The method of claim 13, wherein the base portion is formed by the three-dimensional additive manufacturing method. (Appendix 15) The heat sink according to any one of claims 1 to 12, An electronic device that is placed on the placement surface and is the heat generating body. (Appendix 16) The heat sink according to claim 12; The heating element is provided. the heating element includes a first electronic device placed on the first mounting area and a second electronic device placed on the second mounting area; the first electronic device generates more heat than the second electronic device; The first cross-sectional area is smaller than the second cross-sectional area.

[0101] The disclosed embodiments 1 to 4 and their modified examples should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is indicated by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0102] 1, 1a, 1b heat sink, 2 electronic device, 5 heating element, 6, 6b electronic device, 8 duct, 9 opening, 10 base portion, 11, 12 end face, 13 mounting surface, 13a first mounting area, 13b second mounting area, 14 refrigerant, 15, 16 side face, 18, 26 cavity, 20 heat sink main body portion, 21 first end face, 22 second end face, 23a first surface, 23b second surface, 23c third surface, 24 through hole, 24a first through hole, 24b second through hole, 27 blind hole, 29 slit, 30 three-dimensional additive manufacturing device, 31 laser light source, 32 laser light, 33 optical scanning device, 34 movable table, 35 plate, 35a opening, 36 tank, 37 metal powder, 38 stage, 39 Squeegee.

Claims

1. a solid base portion including a mounting surface on which the heating element is placed; a heat sink main body portion laminated on the base portion on the side opposite to the mounting surface, The heat sink body includes a first end surface and a second end surface opposite the first end surface, The heat sink body is provided with a plurality of through holes through which a coolant can pass, the plurality of through holes extend from the first end surface to the second end surface and are arranged in a direction away from the placement surface, A heat sink, wherein the plurality of through holes do not intersect, merge or branch off from one another.

2. The heat sink of claim 1 , wherein the heat sink body is free of blind holes, cavities and slits.

3. The heat sink according to claim 1 , wherein only the plurality of through holes are provided in the heat sink body.

4. The heat sink of claim 1 , wherein the heat sink body is integrally formed with the base.

5. The heat sink of claim 1 , wherein the heat sink body is formed from the same material as the base.

6. The heat sink of claim 1 , wherein the plurality of through holes are straight through holes.

7. The heat sink according to claim 1 , wherein the plurality of through holes are arranged in a staggered pattern.

8. The heat sink according to claim 1 , wherein a cross-sectional area of ​​the plurality of through holes decreases with increasing distance from the mounting surface.

9. The heat sink of claim 1 , wherein a cross-sectional area of ​​the plurality of through holes increases with increasing distance from the mounting surface.

10. The heat sink according to claim 1 , wherein a cross-sectional area of ​​the plurality of through holes varies in a direction along the mounting surface of the first end surface.

11. The heat sink according to claim 1 , wherein the first end surface is inclined with respect to the mounting surface so that the first end surface protrudes toward the mounting surface.

12. The mounting surface includes a first mounting area and a second mounting area, The plurality of through holes includes a plurality of first through holes and a plurality of second through holes, the first through holes are disposed on an opposite side of the base portion from the first mounting area, the second through holes are disposed on an opposite side of the base portion from the second mounting area, The heat sink of claim 1 , wherein a first cross-sectional area of ​​each of the plurality of first through holes is different from a second cross-sectional area of ​​each of the plurality of second through holes.

13. A method for manufacturing the heat sink according to any one of claims 1 to 12, comprising the steps of: forming the base portion; and forming the heat sink body by three-dimensional additive manufacturing.

14. The method of claim 13 , wherein the base portion is formed by the three-dimensional additive manufacturing process.

15. The heat sink according to any one of claims 1 to 12; An electronic device that is placed on the placement surface and is the heat generating body.

16. The heat sink of claim 12; The heating element is provided. the heat generating body includes a first electronic device placed on the first mounting area and a second electronic device placed on the second mounting area; the first electronic device generates more heat than the second electronic device; The first cross-sectional area is smaller than the second cross-sectional area.

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