Cooling devices for electronic devices

Abstract

To provide a cooling device for an electronic apparatus that can obtain good heat radiation performance when there is an obstacle on the leeward side of a fan that sends air for heat radiation.SOLUTION: A cooling device for an electronic apparatus comprises a heat sink, a fan, a duct, a branch wall, branch ribs, and main ribs. The branch wall is provided in the duct and divides an exhaust direction from an exhaust port into two, and has two plate-like parts continuous to each other on their one sides that are inclined in an air blowing direction of the fan to be separated from each other toward the downstream side in the air blowing direction. The plurality of branch ribs are provided side by side in a thickness direction and projecting from the branch wall, have a crest plate-like shape in which the most projecting apex has an acute angle, and are inserted between the fins. The main ribs are, of the plurality of branch ribs, adjacent to the fins erected on a rear face of a base part in contact with an electronic component, and have a larger volume than that of the other branch ribs.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a cooling device for an electronic device. [Background technology]

[0002] Conventionally, electronic devices such as PCs (Personal Computers) include components that become hot, such as CPUs (Central Processing Units). Such components are generally fitted with heat sinks for heat dissipation, and fans and ducts are installed to ensure an appropriate flow of gas (air) around the heat sink (see, for example, Patent Document 1), with the positions of the intake and exhaust holes of the ducts being determined.

[0003] Depending on the amount and arrangement of components housed in the electronic device's housing, there may be components (obstacles) located downwind of the fan that prevent the gas from passing through smoothly. This undesirably reduces heat dissipation performance.

[0004] Furthermore, fans commonly used in these applications are axial fans (propeller fans), and due to their mechanical design, the airflow speed tends to be slower in the area downstream of the rotating shaft. Also, the electronic components that are the targets of heat dissipation by the heat sink are generally positioned so that they touch the center of the base, and the fins erected in that area tend to become hotter than the other fins. Furthermore, if the electronic components touch multiple points on the base, the fins in the dispersed locations will become hotter. Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the present invention is to provide a cooling device for electronic equipment that can obtain good heat dissipation performance when there is an obstacle downwind of a fan that blows air for heat dissipation. [Means for solving the problem]

[0006] A cooling device for electronic devices according to an embodiment includes a heat sink, a fan, a duct, a branch wall, a branch rib, and a main rib. The heat sink has a base that receives heat from electronic components and has multiple fins arranged in a thickness direction and standing on the base. The fan rotates to blow air, creating an air flow between the fins. The duct covers the heat sink and the fan and has an intake port on the upstream side of the fan's airflow direction and an exhaust port on the downstream side. The branch wall is provided in the duct to bisect the exhaust direction from the exhaust port, and has two plate-shaped portions that are continuous with each other on one side and are inclined with respect to the airflow direction so that they move away from each other toward the downstream side of the fan's airflow direction. A plurality of branch ribs are arranged in a line in the thickness direction and protrude from the branch wall. The most protruding rib has a mountain-shaped plate shape with an acute angle and is inserted into the gaps between the fins. The main rib is one of the multiple branch ribs adjacent to the fin that stands on the backside of the base at a position where the electronic components come into contact, and has a larger volume than the other branch ribs. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing an example of the appearance of a duct according to the first embodiment. [Figure 2] FIG. 2 is a perspective view schematically illustrating an example of the structure of an electronic device to which a duct is attached. [Figure 3] FIG. 3 is a perspective view showing an example of a ventilation hole provided in an electronic device. [Figure 4] FIG. 4 is a plan view illustrating the shape of the duct. [Figure 5] FIG. 5 is a vertical cross-sectional side view illustrating the shape of the duct. [Figure 6] FIG. 6 is a vertical cross-sectional side view illustrating the positional relationship between the duct and components near the exhaust port. [Figure 7] FIG. 7 is a plan view illustrating the shape of the duct of the second embodiment. [Figure 8] FIG. 8 is a plan view illustrating the shape of the duct of the third embodiment. [Figure 9]FIG. 9 is a plan view illustrating the shape of the duct of the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] (First embodiment) The embodiments will be described with reference to the drawings. FIG. 1 is a perspective view showing an example of the appearance of a cooling device 200 according to a first embodiment. FIG. 2 is a perspective view showing an example of the structure of an electronic device 100 to which the cooling device 200 is attached. For ease of explanation, a three-dimensional coordinate system is also shown in the drawings. In the three-dimensional coordinate system, the width direction (left-right direction) of the cooling device 200 and the electronic device 100 is defined as the X-axis direction, the depth direction (front-back direction) is defined as the Y-axis direction, and the height direction (up-down direction) is defined as the Z-axis direction. The positive direction of the Y-axis is the direction from the rear side to the front side of the electronic device 100, and the positive direction of the Y-axis is defined as the "forward" direction. The positive direction of the Z-axis is the direction from bottom to top.

[0009] 1, cooling device 200 includes duct 1, heat sink 2, and fan 3. Duct 1 has a generally box-like shape and covers heat sink 2 and fan 3, which blows air to heat sink 2. Fan 3 blows air in the negative direction (rearward) of the Y axis. An air intake 11 is provided in duct 1 at a position upstream of the air blowing direction of fan 3, and an air exhaust 12 is provided downstream of it.

[0010] Hereinafter, the term "upstream side" simply refers to the upstream side (upwind) based on the airflow direction (negative direction of the Y axis) of the fan 3. Similarly, the term "downstream side" simply refers to the downstream side (downwind) based on the airflow direction of the fan 3.

[0011] The heat sink 2 is attached to a heat-generating electronic component. This "heat-generating electronic component" is, for example, a CPU (Central Processing Unit). The heat generated by the CPU is conducted to the heat sink 2, and the heat from the heat sink 2 is dissipated into the surrounding gas (air). This prevents malfunctions due to overheating of the CPU.

[0012] The heat sink 2 comprises a base 21 and a plurality of fins 22. The base 21 receives the heat generated by the electronic components. A plurality of fins 22 are arranged upright on the base 21 in a line in the thickness direction. The fins 22 are adjacent to each other at a predetermined interval. The base 21 contacts the CPU, and the heat of the CPU is conducted therethrough. The fins 22 dissipate the heat conducted from the base 21, which is continuous with the fins 22, into the air (heat dissipation).

[0013] The heat sink 2 is fixed onto frames 41 to 43, which are layered at predetermined intervals, with helical springs 44 and screws 45. Between the frames 41 and 42, a motherboard 101 (see FIG. 2) is sandwiched.

[0014] The fan 3 is an axial flow fan, a propeller fan with one or more propellers around a rotating shaft. The fan 3 continuously blows air with the rotating propeller. The air blown by the rotation of the fan 3 creates an air flow between the fins 22. The air blown by the fan 3 carries the heat dissipated by the fins 22 and base 21 downstream, promoting heat dissipation. In this way, the fan 3 cools the heat sink 2.

[0015] In this embodiment, the intake port 11, fan 3, heat sink 2, and exhaust port 12 are arranged in this order from upstream to downstream in the airflow direction of fan 3. The gas (air) taken in by fan 3 through intake port 11 and sent out flows mainly around the fins 22 of heat sink 2, removing heat from the fins 22, and is discharged from exhaust port 12.

[0016] Duct 1 allows the air blown by fan 3 to efficiently dissipate heat from heat sink 2, improving the heat dissipation effect. Specifically, duct 1 surrounds the periphery of heat sink 2, defining the area through which the air blown by fan 3 flows to cool heat sink 2. The gas inside duct 1 is replaced by gas taken in from intake port 11 as fan 3 rotates, and is then pushed out from exhaust port 12. This allows the gas around heat sink 2 to be quickly replaced.

[0017] For the purpose of the function of the cooling device 200 as described above, it is desirable that there are no parts (obstacles) that obstruct exhaust air downwind of the exhaust port 12. However, depending on the size of the electronic device 100 equipped with the cooling device 200, the arrangement of the built-in components, etc., an obstacle may be located downstream of the exhaust port 12.

[0018] As shown in FIG. 2, the electronic device 100 includes a motherboard 101, a CPU 102, a memory 103, a solid state drive (SSD) 104, a riser card 105, expansion boards 106 and 107 such as I / O boards, and a housing 110.

[0019] The housing 110 houses the above-mentioned components (motherboard 101, CPU 102, memory 103, SSD 104, riser card 105, and expansion boards 106 and 107 such as I / O boards).

[0020] The motherboard 101 is an example of a board on which electronic components (CPU 102 in this embodiment) are mounted, the heat of which is dissipated by the heat sink 2. The memory 103 and SSD 104 also generate heat in accordance with their operation. This heat is also dissipated by the flow of air inside the housing 110, which is created by the airflow of the fan 3.

[0021] The expansion boards 106 and 107 can be directly connected to the motherboard 101, but in that case, the expansion boards 106 and 107 stand upright on the motherboard 101, which requires the height dimension of the housing 110 to be increased, resulting in an increase in the size of the electronic device 100. To prevent this, the riser card 105 is used.

[0022] The riser card 105 mediates the connection between the expansion boards 106, 107 and the motherboard 101. The riser card 105 has one or more slots that accept the insertion of the expansion boards 106, 107, and is inserted into the slots provided in the motherboard 101. The riser card 105 allows the expansion boards 106, 107 to be positioned and connected approximately parallel to the motherboard 101, rather than standing upright on the motherboard 101. This makes it possible to reduce the height dimension of the housing 110.

[0023] With the above-described arrangement, the expansion boards 106, 107 are located downstream of the exhaust port 12 in the airflow direction of the fan 3. In this case, if the exhaust direction from the exhaust port 12 were backward (negative direction on the Y axis), the expansion boards 106, 107 would become an obstacle that blocks the exhaust. Therefore, in this embodiment, the exhaust direction is configured to avoid the expansion boards 106, 107.

[0024] 3 is a perspective view showing an example of ventilation holes 161 to 167 provided in electronic device 100. This perspective view shows electronic device 100 as seen from the rear side.

[0025] Electronic device 100 includes duct 1, heat sink 2 and fan 3 covered by duct 1, motherboard 101, and housing 110. Housing 110 houses motherboard 101 and duct 1, and housing 110 is provided with ventilation holes 161 to 167 for intake and exhaust.

[0026] The housing 110 includes a front cover 111, a rear cover 112, and an I / O panel 113. The front cover 111 is a part that makes up the front side of the housing 110. The front cover 111 is provided with ventilation holes 161 to 163. The rear cover 112 is a part that makes up the rear side of the housing 110. The rear cover 112 is provided with ventilation holes 164 and 165. The ventilation hole 164 is located at the top of the rear side of the housing 110. The ventilation hole 165 is located at the bottom of the rear side of the housing 110.

[0027] The I / O panel 113 constitutes a part of the rear surface of the housing 110. The I / O panel 113 is provided with ventilation holes 166 and 167. The ventilation holes 166 and 167 are located at the bottom of the rear surface of the housing 110. The ventilation hole 166 is an opening that receives the insertion of a connector into the I / O board (expansion boards 106 and 107).

[0028] Each of the ventilation holes 161 to 167 takes in or exhausts gas (air). Among them, the ventilation holes 164 to 166 provided on the rear side of the housing 110 are mainly responsible for exhausting air.

[0029] In electronic device 100 of this embodiment, expansion boards 106 and 107 are disposed behind CPU 102. Therefore, exhaust port 12 of duct 1 is divided by branch wall 13 and branch ribs 14 and 15 into exhaust port 121 that opens toward the upper rear and exhaust port 122 that opens toward the lower rear so that exhaust air avoids expansion boards 106 and 107 (see FIG. 1 ).

[0030] The shapes of the branch wall 13 and the branch ribs 14, 15 will now be described in more detail with reference to Figures 4 and 5. Figure 4 is a plan view illustrating the shape of the duct 1. Figure 5 is a vertical cross-sectional side view illustrating the shape of the duct 1. The cross section in Figure 5 is taken along line AA in Figure 4.

[0031] Branch wall 13 is disposed inside the edge of exhaust port 12, and divides exhaust port 12 into exhaust port 121 and exhaust port 122. Branch wall 13 has a substantially V-shaped cross section in side view, and the bent portion protrudes toward heat sink 2. This divides the flow direction of the gas that has passed through heat sink 2 into two.

[0032] More specifically, the branch wall 13 has two plate-shaped portions 131 and 132. The plate-shaped portions 131 and 132 are continuous with each other at their upstream edges. The plate-shaped portions 131 and 132 are inclined with respect to the airflow direction of the fan 3 so that the distance between them increases toward the downstream side. The first plate-shaped portion 131 guides the gas flow obliquely upward. The second plate-shaped portion 132 guides the gas flow obliquely downward. As a result, the branch wall 13 guides the exhaust air so as to avoid a partial range downstream of itself, thereby branching the exhaust air.

[0033] The angle formed by the two plate-like portions 131, 132 of the branch wall 13 and the airflow direction (negative direction of the Y-axis) of the fan 3 is 45° or more, and the angle formed by the two plate-like portions 131, 132 is a right angle (90°) or an obtuse angle slightly larger than that. The angle setting of this branch wall 13 is determined taking into consideration the lifespan of the mold, ease of manufacturing, etc.

[0034] The branch ribs 14, 15 are erected on the surface of the branch wall 13 facing the heat sink 2. A plurality of the branch ribs 14, 15 are arranged side by side in the left-right direction at approximately regular intervals. More specifically, a plurality of the branch ribs 14, 15 are arranged side by side in the thickness direction at intervals that allow the branch ribs 14, 15 to be inserted between the fins 22. At least the tip portions of the branch ribs 14, 15 are inserted between the fins 22.

[0035] The branch ribs 14, 15 are provided so as to protrude from the surface of the branch wall 13 facing the heat sink 2 by a distance greater than the distance between the branch wall 13 and the heat sink 2. The branch ribs 14, 15 have a thickness equal to or less than the distance between the fins 22 of the heat sink 2, and have a generally mountain-shaped plate shape. The mountain-shaped edges of the branch ribs 14, 15 may be straight or curved.

[0036] The mountain-shaped edges of the branch ribs 14, 15 are inclined with respect to the airflow direction. The angle formed by the mountain-shaped edges of the branch ribs 14, 15 and the airflow direction of the fan 3 (negative direction of the Y-axis) is effectively in the range of 20 to 45 degrees, and more preferably about 30 degrees. The angle of the mountain-shaped edge at the apex 141, which is the most protruding part, is an acute angle.

[0037] The angle settings of the branch ribs 14, 15 described above are determined based on the results of simulating the cooling effect so that the desired effect can be obtained and the mold can be designed accordingly.

[0038] For example, if the angle formed by the mountain-shaped edges of the branch ribs 14, 15 and the airflow direction of the fan 3 is too large, the desired effect cannot be obtained, and it is desirable that the angle be at least 45° or less to obtain the desired effect.

[0039] Furthermore, if the angle between the mountain-shaped edges of the branch ribs 14, 15 and the airflow direction of the fan 3 is too small (for example, less than 20°), the tops 141 of the branch ribs 14, 15 become too sharp, which is undesirable as it makes filling defects more likely to occur during molding. Furthermore, in this case, if the branch ribs 14, 15 are made long (the dimension from the top 141 to the base is large) in order to ensure a sufficient height dimension at the base, the branch ribs 14, 15 will no longer fit within the exhaust port 121 in a plan view (viewed from the negative Z-axis direction), and the structure of the mold will become complicated.

[0040] In order to avoid the above-mentioned inconveniences and obtain the desired effect while being able to mold using a mold with a simple structure that is less likely to cause filling defects, it is desirable that the angle between the mountain-shaped edges of the branch ribs 14, 15 and the air blowing direction of the fan 3 be between 20° and 45°, and preferably around 30°.

[0041] If the thickness of the base of the branch ribs 14, 15 is 3 mm or less, sink marks are unlikely to occur, and there is no need to apply a mold recess. Furthermore, because there are no walls above or below the branch ribs 14, 15, they can be molded using a standard cavity and core. Therefore, the tips of the branch ribs 14, 15 can be formed with a sharp shape.

[0042] Here, the difference between the branch rib 14 and the branch rib 15 will be described. The branch rib 14 has a thickness less than the spacing between the fins 22 of the heat sink 2, while the branch rib 15 has a thickness approximately equal to the spacing between the fins 22 of the heat sink 2.

[0043] The branch rib 15 is an example of a main rib, and has a larger volume than the other branch ribs 14. The branch rib 15 of this embodiment has a thickness that allows it to contact the adjacent fins 22. In addition, the protruding length of the branch rib 15 from the branch wall 13 is longer than the protruding length of the other branch ribs 14.

[0044] The branch rib 15 is provided at a position adjacent to a fin 22 of the multiple branch ribs 14 that is thought to be prone to becoming hot. The fin 22 that is thought to be prone to becoming hot stands on the backside of the base portion 21 at a position where it will come into contact with a heat-generating electronic component. This embodiment is based on the assumption that the electronic component will come into contact with the center of the base portion 21, and the branch rib 15 is provided at the center in the arrangement direction of the branch ribs 14 (X-axis direction), and is adjacent to the fin 22 that stands at the center of the heat sink 2.

[0045] The duct 1 including the branch ribs 14, 15 is made of a material with high thermal conductivity. An example of this material with high thermal conductivity is what is called a high thermal conductive resin. A high thermal conductive resin is a resin with high thermal conductivity. It should be noted that not the entire duct 1, but only a portion thereof (for example, the branch wall 13, the branch ribs 14, and the branch ribs 15, or at least the branch rib 15) may be made of a metal with high thermal conductivity (for example, copper or aluminum). By using branch ribs 14, 15 made of a material with high thermal conductivity, heat dissipation from the branch ribs 14, 15 and each portion of the duct 1 connected to them can be expected.

[0046] 6 is a vertical cross-sectional side view illustrating the positional relationship between the duct 1 and the components (expansion boards 106, 107) near the exhaust ports 12 (121, 122). The cross section in FIG. 6 is taken along line BB in FIG. 4. As shown here, the exhaust direction of the exhaust ports 121, 122 is set so that the exhaust passes around the nearby components (expansion boards 106, 107) and avoids them.

[0047] In such a configuration, when electronic device 100 is powered on and operates, CPU 102, SSD 104, etc. generate heat and their temperatures rise. When fan 3 operates and blows air, the gas inside duct 1 and housing 110 flows and is ventilated, so heat is removed from CPU 102, etc., preventing them from overheating.

[0048] Branch wall 13 and branch ribs 14, 15 divide the flow direction of air that has been heated through heat sink 2 and is discharged from exhaust port 12 into exhaust port 121 and exhaust port 122. Simulations have shown that ventilation is more efficient and heat buildup in CPU 102 and the like is more suppressed when branch wall 13 and branch ribs 14, 15 are present than when there are no branch wall 13 and branch ribs 14, 15 and obstructions (expansion boards 106, 107) have an effect.

[0049] In this way, duct 1 allows the exhaust to avoid obstacles even if they are present downwind of duct 1, so that heat generated inside electronic device 100 can be dissipated appropriately.

[0050] Furthermore, in the cooling device 200 described above, the branch ribs 14, 15 are made of a material with high thermal conductivity, and therefore easily receive heat dissipated by the fins 22. This can promote heat dissipation by the fins 22. Furthermore, the branch rib 15 has a larger volume than the other branch ribs 14, and therefore can further promote heat dissipation from the neighboring fins 22. The fin 22 adjacent to the branch rib 15 stands on the back surface of the base portion 21 at a position where it contacts a heat-generating electronic component, and therefore tends to require a large amount of heat dissipation, but the promotion of heat dissipation by the branch rib 15 makes it easier to avoid overheating.

[0051] The above-described embodiment can be modified as needed by partially changing the configuration or functions of each of the above-described devices. Therefore, several modifications of the above-described embodiment will be described below as other embodiments. The following mainly describes differences from the above-described embodiment, and the same reference numerals will be used for common features with the content already described, and detailed description will be omitted. The modifications described below may be implemented individually or in appropriate combination.

[0052] (Second embodiment) 7 is a plan view illustrating the shape of the duct 1 of the second embodiment. In this embodiment, a branch rib 16 is provided as an example of a main rib instead of the branch rib 15 of the first embodiment.

[0053] This embodiment is based on the assumption that heat-generating electronic components will come into contact with two locations near the edges of the base portion 21, rather than the center. In this assumption, the fins 22 near the edges are likely to become hot. Therefore, branch ribs 16, which are main ribs, are provided at two locations near the edges to promote heat dissipation from the fins 22 near the edges.

[0054] As in this embodiment, it is assumed that the fins 22 are likely to become hot depending on the position on the base portion 21 where the heat-generating electronic components touch, and the volume of the branch ribs 16 adjacent to the fins 22 is increased by making them thicker and longer than the other branch ribs 14, and the branch ribs 16 are brought into contact with the fins 22, thereby improving heat dissipation performance.

[0055] (Third embodiment) 8 is a plan view illustrating the shape of a duct 1 according to a third embodiment. In this embodiment, branch ribs 171 to 175 are provided instead of the branch ribs 14 and 15 of the first embodiment. The branch rib 171 is an example of a main rib in this embodiment.

[0056] The branch ribs 171 to 175 have different protruding lengths from the branch wall 13. The branch ribs 171, which is the main rib, have the longest protruding lengths of the branch ribs 171 to 175, and the other branch ribs 172 to 175 are set so that the closer they are to the branch rib 171, the longer they are, and the farther they are, the shorter they are. The branch ribs 171 form a pair and are adjacent to the fins 22 that stand in the center of the heat sink 2. In other words, an imaginary line connecting the tops of the branch ribs 171 to 175 forms a mountain shape.

[0057] According to this configuration, the branch ribs 171 to 175 do not come into contact with the fins 22, which makes assembly easier than in the first embodiment, and also makes up for the reduced heat dissipation performance that would otherwise result from not coming into contact with the fins 22.

[0058] (Fourth embodiment) 9 is a plan view illustrating the shape of a duct 1 according to a fourth embodiment. In this embodiment, branch ribs 181 to 185 are provided instead of the branch ribs 171 to 175 of the third embodiment. An example of a main rib in this embodiment is the branch rib 181. The other branch ribs 182 to 185 are the same as the branch ribs 172 to 175.

[0059] The branch rib 181 has a thickness that allows it to contact the fins 22, unlike that of the third embodiment.

[0060] According to this configuration, the heat dissipation performance can be improved compared to the third embodiment.

[0061] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0062] 100...Electronic equipment, 101...Motherboard, 102...CPU, 103...Memory, 104...SSD, 105...riser card, 106,107...expansion board, 110... housing, 111... front cover, 112... rear cover, 113...I / O panel, 161~167...ventilation holes, 200...Cooling device, 1...duct, 11...intake port, 12, 121, 122...exhaust port, 13 ... branch wall, 131, 132 ... plate-shaped portion, 14...branch rib, 141...top, 15...branch rib (main rib), 151...top, 16... Branch rib (main rib), 171... Branch rib (main rib), 172~175... Branch rib, 181... Branch rib (main rib), 182~185... Branch rib, 2...heat sink, 21...base portion, 22...fin, 3...fans, 41~43...Frame, 44...Heavy coil spring, 45...Screw. [Prior art documents] [Patent documents]

[0063] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-283171 [Patent Document 2] Patent Publication No. 2021-185592

Claims

1. a heat sink having a base portion that receives heat from electronic components and has multiple fins arranged in a thickness direction; a fan that creates an air flow between the fins by rotating the fan; a duct that covers the heat sink and the fan and has an air intake port on an upstream side and an air exhaust port on a downstream side in the airflow direction of the fan; a branch wall provided in the duct to divide the direction of exhaust air from the exhaust port into two, the branch wall having two plate-like portions that are continuous with each other on one side and are inclined with respect to the air blowing direction so as to move away from each other toward a downstream side in the air blowing direction of the fan; a plurality of branch ribs arranged in a thickness direction, protruding from the branch wall, each having a mountain-shaped plate shape with an acute angle at its most protruding apex, and inserted into the gaps between the fins; Among the plurality of branch ribs, a main rib is adjacent to the fin standing on the back surface of the base portion at a position where the electronic component comes into contact, and has a volume larger than that of the other branch ribs; A cooling device for electronic devices comprising:

2. The main rib has a thickness that touches the adjacent fins. The cooling device for electronic devices according to claim 1 .

3. The length of the main rib projecting from the branch wall is longer than the length of the other branch ribs projecting from the branch wall. The cooling device for electronic devices according to claim 1 .

4. The main rib is adjacent to the fin standing in the center of the heat sink. The cooling device for electronic devices according to claim 1 .

5. The protruding lengths of the branch ribs are set so that the closer they are to the main rib, the longer they are, and the farther they are from the main rib, the shorter they are. An imaginary line connecting the tops of the branch ribs forms a mountain shape. The cooling device for electronic devices according to claim 1 .

6. At least the main rib of the branch ribs is made of a material with high thermal conductivity. The cooling device for electronic devices according to claim 1 .

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