Heat Sinks and Cooling Devices

Abstract

To provide a cooling device that suppresses stagnation of the flow of fluid while increasing cooling efficiency by increasing the number of flow channels partitioned by fins.SOLUTION: A heat sink 1α is used together with a fluid flow generation device that generates the flow of fluid with the rotation around a central axis extending vertically. The heat sink includes a body part which has an upper surface opposed in the vertical direction to the fluid flow generation device, and a fin which extends upwards from the upper surface and partitions multiple flow channels. Each of the multiple flow paths obtained from the multiple flow channels has an inlet 131 to which the fluid discharged from the fluid flow generation device flows and an outlet 132 which discharges the fluid that has flown thereto from the inlet to the outside. A portion of the multiple fluid paths has a first branch part which branches from the first fluid path on the downstream side relative to the inlet, and a first confluent part which joins the second fluid path that has a different inlet on the downstream side relative to the first branch part.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present invention relates to a heat sink and a cooling device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is known a cooling device that includes a heat sink thermally connected to a heat generating element, and an electric fan device that blows cooling air to the heat sink (see, for example, Patent Document 1).

[0003] The heat sink comprises a heat receiving portion that receives heat from a heat sink, a plurality of heat dissipation fins, and a cooling air passage through which cooling air is blown. The cooling air passage is formed along the heat dissipation fins. The electric fan device comprises a centrifugal impeller. The impeller draws in air and expels it toward the cooling air passage. The air flowing through the cooling air passage exchanges heat with the heat sink and functions as a main cooling medium that removes heat from the heat generating body. The air that has been warmed by heat exchange with the heat sink is discharged to the outside from the downstream end of the cooling air passage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-23281 A Summary of the Invention [Problem to be solved by the invention]

[0005] By the way, it is expected that increasing the number of heat dissipation fins will increase the heat dissipation area and increase the cooling capacity. However, simply increasing the number of heat dissipation fins and increasing the number of cooling air ducts may cause poor air flow. In particular, in a cooling air duct that is long from the inlet to the outlet, if heat dissipation fins are placed in the middle of the air duct to branch the air duct and increase the number of branches, the air flow is likely to stagnate.

[0006] An object of the present invention is to provide a technique that can increase the number of flow paths defined by fins to improve cooling efficiency while suppressing stagnation of the fluid flow. [Means for solving the problem]

[0007] An exemplary heat sink of the present invention is used with a fluid flow generating device that generates a fluid flow by rotating around a central axis extending vertically. The heat sink has a main body having an upper surface facing the fluid flow generating device in the vertical direction, and fins extending upward from the upper surface and dividing a plurality of flow paths. The upper surface includes a flat area in which the fins are not provided and which faces the fluid flow generating device. The fins are arranged around the flat area. Four areas divided by an X-axis and a Y-axis that intersect with each other at an intersection point between the central axis and the upper surface and extend in a direction in which the upper surface spreads are defined as a first area, a second area, a third area, and a fourth area in the order of being in the opposite direction to the rotation direction of the fluid flow generating device. Each of a plurality of fluid paths obtained from the plurality of flow paths has an inlet through which the fluid discharged from the fluid flow generating device flows in, and an outlet through which the fluid that entered from the inlet is discharged to the outside. The outlet of each of the plurality of fluid paths is provided in the first area. The plurality of fluid paths include a short-distance path that passes through the second region and the first region from the inlet to the outlet, and a long-distance path that passes through the third region, the second region, and the first region from the inlet to the outlet. The long-distance path is configured using a long-distance flow path that extends from the third region to the second region. In a plan view from above, the long-distance flow paths are arranged in a direction away from the intersection. Among the plurality of long-distance flow paths, an outermost long-distance flow path that is located at a position farthest from the intersection in the second region has a junction part that merges with the other flow paths in at least one of the second region and the third region.

[0008] An exemplary cooling device of the present invention includes a heat sink having the above-described configuration and the fluid flow generating device. Effect of the Invention

[0009] According to the exemplary embodiment of the present invention, the number of flow paths defined by the fins can be increased to improve cooling efficiency, while preventing stagnation of the fluid flow. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a plan view of a cooling device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a view of FIG. 1 with the cover removed. [Diagram 3] FIG. 3 is a vertical cross-sectional view of a fluid flow generating device according to an embodiment of the present invention. [Figure 4] FIG. 4 is a simplified cross-sectional view of a cooling device according to an embodiment of the present invention. [Diagram 5] FIG. 5 is a plan view of a heat sink according to an embodiment of the present invention. [Figure 6] FIG. 6 is a diagram for explaining a main path and a sub path of the heat sink according to the embodiment of the present invention. [Figure 7] FIG. 7 is a diagram for explaining details of the sub-route according to the embodiment of the present invention. [Figure 8] FIG. 8 is a diagram for explaining a branching portion and a junction portion in a main route according to an embodiment of the present invention. [Figure 9] FIG. 9 is a diagram focusing on the third main path and the fourth main path shown in FIG. [Figure 10] FIG. 10 is a diagram focusing on the first main path and the second main path shown in FIG. [Figure 11] FIG. 11 is a diagram focusing on the 10th main path shown in FIG. [Figure 12] FIG. 12 is a plan view of the heat sink of the first modified example. [Figure 13] FIG. 13 is a diagram for explaining details of the main path in the heat sink of the first modified example. [Figure 14] FIG. 14 is a plan view of a heat sink according to a second modified example. [Figure 15]FIG. 15 is a diagram for explaining details of the main path in the heat sink of the second modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In this specification, a direction parallel to a central axis C of a fluid flow generating device 2 used with a heat sink 1 as shown in FIG. 3 is referred to as an "axial direction", a direction perpendicular to the central axis C is referred to as a "radial direction", and a direction along a circular arc centered on the central axis C is referred to as a "circumferential direction".

[0012] In this specification, the shape and positional relationship of each part will be described assuming that the axial direction is the up-down direction and that the side on which the fluid flow generating device 2 is provided with respect to the heat sink 1 is the upside. However, this definition of the up-down direction is not intended to limit the orientation of the heat sink and cooling device according to the present invention when used.

[0013] In addition, in this specification, "upstream" and "downstream" generally refer to upstream and downstream in the flow direction of the fluid from the inlet 131 to the outlet 132 shown in Figure 2 by rotating the fluid flow generating device 2.

[0014] <1.Cooling device> Fig. 1 is a plan view of a cooling device 100 according to an embodiment of the present invention. Fig. 1 is a top view of the cooling device 100. As shown in Fig. 1, the cooling device 100 includes a heat sink 1 and a fluid flow generating device 2. The cooling device 100 further includes a cover 3.

[0015] The heat sink 1 is used together with the fluid flow generating device 2. The heat sink 1 is a heat dissipating member made of a metal material having excellent thermal conductivity, such as aluminum, copper, an aluminum alloy, or a copper alloy. FIG. 2 is a view of FIG. 1 with the cover 3 removed. In FIG. 2, the fluid flow generating device 2 is shown in a simplified form. As shown in FIG. 2, the heat sink 1 has a main body 10 and fins 11. The main body 10 and the fins 11 are the same member.

[0016] The main body 10 has a rectangular shape when viewed from above. However, the main body 10 may have a shape other than a rectangle, for example, a polygonal shape other than a rectangle. The main body 10 has an upper surface 10a that faces the fluid flow generating device 2 in the up-down direction. The upper surface 10a extends in a direction perpendicular to the up-down direction. The upper surface 10a may be a flat surface, or may have an uneven surface. A peripheral wall 10b is provided on the periphery of the upper surface 10a, extending upward except for one of the four sides.

[0017] The fins 11 extend upward from the upper surface 10a. A plurality of the fins 11 are provided on the upper surface 10a. In a plan view from above, the shapes of the fins 11 vary. For example, in a plan view from above, some fins 11 are linear, other fins 11 are curved such as an arc, and still other fins 11 are shaped having linear portions and curved portions. The fins 11 may be dot-shaped in a plan view from above. The dot-shaped fins may be, for example, cylindrical, prismatic, or pyramidal.

[0018] The fins 11 define a plurality of flow paths 12. The flow paths 12 are paths through which a fluid passes. The flow paths 12 are formed at positions sandwiched between two fins 11. The flow paths 12 are also formed at positions sandwiched between the fins 11 and the peripheral wall 10b. In this embodiment, the flow paths 12 are groove-shaped. The fluid flowing through the flow paths 12 comes into contact with the fins 11 and exchanges heat with the fins 11. In detail, the fluid absorbs heat from the fins 11. In other words, the fins 11 are heat dissipation fins.

[0019] In Fig. 2, thick dashed lines diagrammatically show a plurality of fluid paths 13 obtained from a plurality of flow paths 12. Note that Fig. 2 shows only some of the plurality of fluid paths 13 obtained from a plurality of flow paths 12. Each of the plurality of fluid paths 13 has an inlet 131 and an outlet 132. Each fluid path 13 is a path that a fluid follows from a certain inlet 131 to a certain outlet 132.

[0020] The inlet 131 is a point into which the fluid discharged from the fluid flow generating device 2 flows. The outlet 132 is a point from which the fluid that entered from the inlet 131 is discharged to the outside. Here, the outside means the outside of the heat sink 1. In other words, the fluid path 13 is a path along which the fluid discharged from the fluid flow generating device 2 follows until it reaches the outside of the heat sink 1. The fluid passing through each fluid path 13 exchanges heat with the fins 11.

[0021] As shown in FIG. 2, the fluid flow generating device 2 generates a fluid flow by rotating around a central axis C extending vertically. The open arrows in FIG. 2 indicate the fluid flow. In the fluid flow generating device 2, the direction in which the fluid flows in is different from the direction in which the fluid is discharged. In this embodiment, the direction in which the fluid flows in is the vertical direction, and the direction in which the fluid is discharged is a direction perpendicular to the vertical direction. In this embodiment, the rotation direction RD of the fluid flow generating device 2 rotating around the central axis C is clockwise. However, the rotation direction of the fluid flow generating device 2 may be counterclockwise. When the rotation direction of the fluid flow generating device 2 is counterclockwise, the arrangement and shape of the fins 11 are changed.

[0022] The fluid may be, for example, a gas or a liquid. The gas may be, for example, air. The liquid may be, for example, water or a coolant liquid. In this embodiment, the fluid is air.

[0023] Moreover, the fluid flow generating device 2 is, for example, a fan or a pump. In this embodiment, the fluid flow generating device 2 is a centrifugal fan that takes in air from above and discharges the air in a direction perpendicular to the up-down direction. According to this configuration, by driving the fluid flow generating device 2, air is taken into the cooling device 100 from the outside, and the taken-in air exchanges heat while passing through each fluid path 13 and is discharged to the outside. This air flow can efficiently cool the object to be cooled.

[0024] Fig. 3 is a vertical cross-sectional view of a fluid flow generating device 2 according to an embodiment of the present invention. For ease of understanding, a part of a main body 10 of a heat sink 1 is also shown in Fig. 3. As shown in Fig. 3, the fluid flow generating device 2 has a motor 20, an impeller 21, and a support part 22.

[0025] The motor 20 has a shaft 201, a stator 202, and a rotor 203. The shaft 201 extends vertically along a central axis C. The shaft 201 is rotatably supported by a bearing 204 disposed radially outward of the shaft 201. The bearing 204 is accommodated in a covered cylindrical bearing holder 205 supported by the support portion 22 and held by the bearing holder 205. Note that in this embodiment, the bearing 204 is a sleeve bearing, but the bearing may be of another type, for example, a ball bearing.

[0026] The stator 202 is annular about a central axis C. The stator 202 is disposed radially outward of a bearing holder 205 and fixed to the bearing holder 205. The rotor 203 is cylindrical about a central axis C. An annular magnet 203a is fixed to a radially inner surface of the rotor 203. The magnet 203a is disposed radially outward of the stator 202 with a gap therebetween. By supplying a drive current to the stator 202, a rotational torque is generated between the magnet 203a and the stator 202. This causes the rotor 203 to rotate relative to the stator 202.

[0027] The impeller 21 has an impeller cup 211 and a plurality of blades 212. The impeller cup 211 is cylindrical with a bottom and centered on a central axis C, and is fixed to the shaft 201. The rotor 203 is fixed to a radially inner surface of the impeller cup 211. That is, the impeller 21 rotates together with the rotation of the rotor 203.

[0028] Each blade 212 extends from a radially outer surface of the impeller cup 211 in a direction away from the central axis C. The blades 212 are arranged at intervals in the circumferential direction. The direction away from the central axis C may be parallel to the radial direction or may be inclined relative to the radial direction. Air flow is generated by the rotation of each blade 212.

[0029] The support part 22 that supports the motor 20 is fixed to the lower surface of the cover 3. For this reason, in this embodiment, the fluid flow generating device 2 is disposed at a distance from the upper surface 10a of the main body part 10 in the vertical direction. However, the support part 22 may be integrated with the cover 3. This makes it possible to reduce the number of parts and reduce costs. Furthermore, the support part 22 may be attached to the upper surface 10a. In other words, the upper surface 10a that faces the fluid flow generating device 2 in the vertical direction may be in contact with the fluid flow generating device 2.

[0030] 1, the cover 3 covers an upper surface 10a of the body 10 of the heat sink 1. The cover 3 is made of a metal material having excellent thermal conductivity, such as iron or an iron alloy. The cover 3 is attached to the body 10 of the heat sink 1 by a fixing method, such as screws or brazing.

[0031] A circular cover opening 3a penetrating in the vertical direction is provided near the center of the cover 3. The fluid flow generating device 2 attached to the lower surface of the cover 3 is exposed to the outside of the cooling device 100 through the cover opening 3a. When the fluid flow generating device 2 is driven, fluid flows from the outside to the inside of the cooling device 100 through the cover opening 3a. Furthermore, when the fluid flow generating device 2 is driven, the fluid drawn into the inside passes through a fluid path 13 formed in the heat sink 1 and is discharged to the outside of the cooling device 100 from a portion where the peripheral wall 10b is not provided.

[0032] Fig. 4 is a simplified cross-sectional view of a cooling device 100 according to an embodiment of the present invention. As shown in Fig. 4, the main body 10 has a cooled object accommodating portion 101 for accommodating an object to be cooled on the lower surface 10c side. The object to be cooled is an object to be cooled, and in the example shown in Fig. 4, this corresponds to the heating element 4 and the substrate 5 on which the heating element 4 is mounted. Examples of the heating element 4 include heat generating elements such as semiconductor chips and transistors.

[0033] In this embodiment, the cooled object accommodating portion 101 has an element accommodating portion 101a and a substrate accommodating portion 101b. However, only one of the element accommodating portion 101a and the substrate accommodating portion 101b may be provided. The element accommodating portion 101a is a recess in which the lower surface 10c of the main body portion 10 is recessed upward, and accommodates at least a part of the heat generating element, which is the heat generating body 4. The heat generating body 4 accommodated in the element accommodating portion 101a is preferably in contact with the main body portion 10. Note that the heat generating body 4 and the main body portion 10 only need to be in thermal contact with each other, and may be configured such that, for example, thermal grease is interposed between the heat generating body 4 and the main body portion 10. The substrate accommodating portion 101b is a portion that accommodates the substrate 5, and the substrate 5 accommodated in the substrate accommodating portion 101b is preferably in thermal contact with the main body portion 10.

[0034] The fluid passing through the multiple fluid paths 13 by driving the fluid flow generating device 2 exchanges heat with the heat sink 1 and takes heat from the object to be cooled. This cools the object to be cooled. The fluid warmed by the heat exchange with the heat sink 1 is discharged to the outside of the cooling device 100 through the outlet 132 of the fluid path 13. In this embodiment, since a wide range of the heat sink 1 used together with the fluid flow generating device 2 can be cooled by the fluid, the object to be cooled can be cooled efficiently. In addition, in this embodiment, a cooled object accommodating portion 101 for accommodating the object to be cooled is provided on the lower surface side of the heat sink 1 that can cool a wide range, and restrictions on the arrangement of the object to be cooled can be reduced.

[0035] <2. Heat sink details> (2-1. Overview of fluid path) FIG. 5 is a plan view of a heat sink 1 according to an embodiment of the present invention. FIG. 5 is a view of the heat sink 1 as seen from above. The dashed arrows in FIG. 5 indicate the flow of fluid. In this embodiment, the flow of fluid is an air flow, that is, wind. In FIG. 5, as in FIG. 2, some of the multiple fluid paths 13 obtained from the multiple flow paths 12 are shown by thick dashed lines. The white arrow RD in FIG. 5 indicates the rotation direction of the fluid flow generating device 2.

[0036] 5, four regions R1, R2, R3, and R4 are defined by an X-axis and a Y-axis that intersect with each other at an intersection CP between the central axis C and the upper surface 10a and extend in the direction in which the upper surface 10a spreads. These regions are designated as a first region R1, a second region R2, a third region R3, and a fourth region R4 in the order of their directions opposite to the rotation direction RD of the fluid flow generating device 2. The direction in which the upper surface 10a spreads is perpendicular to the up-down direction. The rotation direction RD is a clockwise direction, and the direction opposite to the rotation direction RD is a counterclockwise direction.

[0037] In this embodiment, the X-axis and the Y-axis are perpendicular to each other. However, the X-axis and the Y-axis do not have to be perpendicular to each other. Furthermore, in this embodiment, the X-axis and the Y-axis do not divide the upper surface 10a of the main body 10 evenly into four. However, the X-axis and the Y-axis may divide the upper surface 10a of the main body 10 evenly into four.

[0038] 5, in a plan view from above, the inlet 131 of each fluid path 13 is provided in at least one of the four regions R1, R2, R3, and R4. Each inlet 131 may be provided in only one of the four regions R1, R2, R3, and R4, or may be provided across multiple regions.

[0039] In this embodiment, from the first region R1, a first inlet 131a, a second inlet 131b, a third inlet 131c, a fourth inlet 131d, a fifth inlet 131e, a sixth inlet 131f, a seventh inlet 131g, an eighth inlet 131h, a ninth inlet 131i, a tenth inlet 131j, an eleventh inlet 131k, and a twelfth inlet 131l are provided in order according to the rotation direction RD of the fluid flow generating device 2.

[0040] The first inlet 131a and the second inlet 131b are provided in the first region R1. The third inlet 131c, the fourth inlet 131d, the fifth inlet 131e, and the sixth inlet 131f are provided in the fourth region R4. The seventh inlet 131g and the eighth inlet 131h are provided in the third region R3. The ninth inlet 131i is provided across the third region R3 and the second region R2. The tenth inlet 131j, the eleventh inlet 131k, and the twelfth inlet 131l are provided in the second region R2.

[0041] 5, in a plan view from above, the outlet 132 of each fluid path 13 is provided in the first region R1. In particular, the outlets 132 of all of the multiple fluid paths 13 are provided in the first region R1. That is, in the heat sink 1 of this embodiment, the outlets 132 of each fluid path 13 are provided biased in a specific direction.

[0042] In this embodiment, in the first region R1, a first outlet 132a, a second outlet 132b, a third outlet 132c, a fourth outlet 132d, a fifth outlet 132e, a sixth outlet 132f, a seventh outlet 132g, an eighth outlet 132h, a ninth outlet 132i, a tenth outlet 132j, and an eleventh outlet 132k are provided, in that order from upstream to downstream in the rotation direction RD of the fluid flow generating device 2.

[0043] In this embodiment, a configuration in which only one fluid path 13 is obtained for one inlet 131 and a configuration in which multiple fluid paths 13 are obtained for one inlet 131 are mixed. However, the present invention is not limited to such a configuration, and for example, a configuration in which only one of the former configuration and the latter configuration is provided may be used. In the former configuration, the relationship between the inlet 131 and the outlet 132 is always one-to-one. In the latter configuration, for example, a configuration in which the outlet 132 is shared by multiple fluid paths 13 may be included. In addition, the latter configuration may include a configuration in which the outlet 132 is different for each of the multiple fluid paths 13.

[0044] 5, for example, for the seventh inlet 131g provided in the third region R3, only one fluid path 13 is obtained from the seventh inlet 131g to the third outlet 132c. For the sixth inlet 131f provided in the fourth region R4, a total of three fluid paths 13 are obtained: a fluid path 13 from the sixth inlet 131f to the first outlet 132a, and two fluid paths 13 from the sixth inlet 131f to the second outlet 132b.

[0045] The first inlet 131a, the second inlet 131b, the third inlet 131c, the fourth inlet 131d, the fifth inlet 131e, the sixth inlet 131f, the tenth inlet 131j, and the eleventh inlet 131k are shared among the multiple fluid paths 13. The first outlet 132a, the second outlet 132b, the seventh outlet 132g, the eighth outlet 132h, the tenth outlet 132j, and the eleventh outlet 132k are shared among the multiple fluid paths 13.

[0046] In this embodiment, the fins 11 include Y-shaped fins 11a and 11b. By providing the Y-shaped fins 11a and 11b on the upper surface 10a, the rigidity of the heat sink 1 can be improved. Furthermore, by forming the flow path 12 with the Y-shaped fins 11a and 11b, it is possible to easily guide the fluid in different directions. In this embodiment, the number of the Y-shaped fins 11a and 11b is two, but it may be other than two. One of the two Y-shaped fins 11a exists across the third region R3 and the fourth region R4. The other of the two Y-shaped fins 11b exists across the first region R1 and the fourth region R4.

[0047] In the heat sink 1, in a plan view from above, in at least some of the fluid paths 13 having the inlets 131 in the fourth region R4, the direction of the fluid flow changes at an acute angle midway. As shown in Fig. 5, in this embodiment, the fourth region R4 is provided with four inlets 131, namely, the third inlet 131c, the fourth inlet 131d, the fifth inlet 131e, and the sixth inlet 131f. Of these four inlets 131, the fluid path 13 having the third inlet 131c as the inlet 131 and the fluid path 13 having the fourth inlet 131d as the inlet 131 have the direction of the fluid flow change at an acute angle midway.

[0048] The term "midway" refers to a position or region between the inlet 131 and the outlet 132. In other words, in at least a part of the fluid path 13 having the inlet 131 in the fourth region R4, the flow direction of the fluid changes at an acute angle downstream of the inlet 131. In this embodiment, the flow direction of the fluid does not change at an acute angle at the inlet 131. In addition, the change in the flow direction of the fluid at an acute angle refers to a state in which the angle between the flow direction of the fluid upstream of a certain position or narrow region and the flow direction of the fluid downstream of the boundary becomes an acute angle. The narrow region is a narrow region having a length of 1 / 5 or less of the total length of the fluid path 13 in each fluid path 13. The narrow region is preferably a narrow region having a length of 1 / 8 or less of the total length of the fluid path 13 in each fluid path 13.

[0049] Here, as a comparative example to this embodiment, consider a case where the fluid path 13 extends only in the direction along the rotation direction RD of the fluid flow generating device 2. In this case, it is considered that the fluid flow in the fluid path having the inlet 131 in the fourth region R4 becomes poor because the distance to the outlet 132 provided in the first region R1 becomes long. In other words, it is considered that the fluid flowing through the fluid path will contribute less to cooling.

[0050] On the other hand, according to the configuration of this embodiment, at least a part of the fluid path 13 having the inlet 131 in the fourth region R4 is formed so as to change the direction of the fluid flow at an acute angle. For this reason, the distance to the outlet 132 can be shortened for at least a part of the fluid path 13 having the inlet 131 in the fourth region R4, thereby improving the flow of the fluid. That is, according to this configuration, the degree of contribution of the fluid flowing through the fluid path 13 having the inlet 131 in the fourth region R4 to cooling can be increased. In addition, according to this configuration, the fluid path 13 can be formed in a wide range of the fourth region R4, which is easily a dead space in the past, and the range through which the fluid flows can be widened, thereby improving the cooling efficiency. In addition, in this configuration, the direction of the fluid flow changes at an acute angle downstream of the inlet 131, and the direction of the fluid flow can be changed more efficiently than in a configuration in which the direction of the fluid flow changes abruptly at the inlet of the path.

[0051] (2-2. Main and sub-routes) Fig. 6 is a diagram for explaining the main path 13M and the sub path 13S of the heat sink 1 according to the embodiment of the present invention. Fig. 6 is a plan view of the heat sink 1 as seen from above, similar to Fig. 5. In Fig. 6, the thick solid lines are provided to make it easier to roughly grasp the types of the fluid paths 13, and are not necessarily intended as boundaries for distinguishing the types of the fluid paths 13. Also, the main path 13M, the sub path 13S, and the auxiliary path 13A shown by the thick dashed lines in Fig. 6 are merely examples of a plurality of paths.

[0052] At least some of the multiple fluid paths 13 formed on the upper surface 10a of the main body 10 are divided into a main path 13M and a sub path 13S. In this embodiment, some of the multiple fluid paths 13 are divided into the main path 13M and the sub path 13S. In detail, the multiple fluid paths 13 are divided into the main path 13M, the sub path 13S, and the auxiliary path 13A.

[0053] The main path 13M is a fluid path 13 in which the fluid flows in the same direction as the rotation direction RD of the fluid flow generating device 2. The fluid flows in the same direction as the rotation direction RD, when viewed from above in a plan view, refers to a state in which the fluid flowing through the point of interest flows at an inclination in the same direction as the rotation direction RD of the fluid flow generating device 2 with respect to a virtual line connecting the central axis C and the point of interest of the fluid path 13. In the main path 13M, the fluid flows in the same direction as the rotation direction RD of the fluid flow generating device 2 over the entire range or almost the entire range. For example, when the flow direction of the fluid is changed to adjust the discharge direction of the fluid near the outlet 132, this may be the case for almost the entire range. In this embodiment, in the main path 13M, the fluid flows in the same direction as the rotation direction RD of the fluid flow generating device 2 over the entire range.

[0054] In this embodiment, the fluid path 13 having an inlet 131 in the fourth region R4, the third region R3 or the second region R2 and an outlet 132 which is any one of the first outlet 132a, the second outlet 132b, the third outlet 132c, the fourth outlet 132d, the fifth outlet 132e, the sixth outlet 132f, and the seventh outlet 132g (see Figure 5) is the main path 13M.

[0055] As a preferred embodiment, the main path 13M includes at least a portion of the fluid path 13 having the inlet 131 in the third region R3. In detail, the main path 13M includes a plurality of fluid paths 13 having the seventh inlet 131g, the eighth inlet 131h, and the ninth inlet 131i at their inlets 131, at least a portion of which is present in the third region R3. This allows the main path 13M to cool a wide range including not only the first region R1 and the second region R2, but also the third region R3.

[0056] The sub-path 13S is a fluid path 13 having a portion where the flow direction of the fluid changes at an acute angle from the rotation direction of the fluid flow generating device 2 to the opposite direction. The fluid flows in the opposite direction to the rotation direction RD, when viewed in a plan view from above, meaning that the fluid flowing through a point of interest in the fluid path 13 flows at an angle opposite to the rotation direction RD of the fluid flow generating device 2 with respect to an imaginary line connecting the central axis C and the point of interest. The portion where the flow changes at an acute angle is downstream of the inlet 131. The portion where the flow changes at an acute angle is a certain position or a narrow area of ​​the fluid path 13.

[0057] In this embodiment, the fluid path 13 having an inlet 131 in the fourth region R4 or the first region R1 and an outlet 132 serving as the tenth outlet 132j ​​or the eleventh outlet 132k (see FIG. 5) is the sub-path 13S. With this configuration, a wide range of the heat sink 1 can be cooled using the main path 13M, while an even wider range of the heat sink 1 can be cooled by arranging the sub-path 13S in an area of ​​the heat sink 1 where it is difficult to arrange the main path 13M.

[0058] As a preferred embodiment, the sub-path 13S includes at least a part of the fluid paths 13 having the inlet 131 in the first region R1, in addition to at least a part of the fluid paths 13 having the inlet 131 in the fourth region R4. In detail, the sub-path 13S includes a plurality of fluid paths 13 having the third inlet 131c and the fourth inlet 131d (see FIG. 5) in the fourth region R4 at the inlet 131. The sub-path 13S also includes a plurality of fluid paths 13 having the first inlet 131a and the second inlet 131b (see FIG. 5) in the first region R1 at the inlet 131. In this configuration, the fluid can be sent from the first region R1 to the fourth region R4, and the fourth region R4, which is difficult to cool by the main path 13M, can be cooled efficiently.

[0059] The auxiliary path 13A is a fluid path 13 having a portion where the fluid flow direction changes from the rotation direction RD of the fluid flow generating device 2 to the opposite direction. However, in the auxiliary path 13A, the fluid flow direction does not change at an acute angle. That is, the auxiliary path 13A is different from the main path 13M and the sub path 13S. The portion where the fluid flow direction changes from the rotation direction RD to the opposite direction is located downstream of the inlet 131.

[0060] In this embodiment, the fluid path 13 having the inlet 131 in the second region R2 and the outlet 132 being the eighth outlet 132h or the ninth outlet 132i (see FIG. 5) is the auxiliary path 13A. The auxiliary path 13A does not necessarily have to be provided. However, by providing the auxiliary path 13A, a wide range of the heat sink 1 can be cooled.

[0061] As described above, in this embodiment, the Y-shaped fin 11b is provided across the first region R1 and the fourth region R4. The Y-shaped fin 11b has a portion in the first region R1 that extends linearly toward the outlet 132. By providing the Y-shaped fin 11b, the sub-path 13S can be formed in a manner that distinguishes it from other types of paths. In this embodiment, the other types of paths are the auxiliary paths 13A. Note that, when it is not necessary to completely distinguish it from other types of paths, a V-shaped fin may be disposed instead of the Y-shaped fin 11b. When the Y-shaped fin 11b of this embodiment is replaced with a V-shaped fin, a part of the sub-path 13S and a part of the auxiliary path 13A merge with each other.

[0062] In this embodiment, the Y-shaped fin 11b existing across the first region R1 and the fourth region R4 has a portion extending linearly toward the outlet 132 disposed closer to the fourth region R4 than the center in the direction in which the multiple outlets 132 are arranged. However, this arrangement may be changed. For example, the portion extending linearly toward the outlet 132 may be disposed in the center in the direction in which the multiple outlets 132 are arranged. In this case, a configuration may be adopted in which the auxiliary path 13A is not provided.

[0063] (2-3. Details of the alternative route) Fig. 7 is a diagram for explaining details of the sub-path 13S according to the embodiment of the present invention. Fig. 7 is a diagram showing an enlarged portion of the heat sink 1 as viewed from above. At least some of the multiple sub-paths 13S have a sub-path junction 133 that merges with other sub-paths 13S. In this embodiment, each of the multiple sub-paths 13S has a sub-path junction 133 that merges with other sub-paths 13S.

[0064] In each sub-path 13S, the sub-path junction 133 is provided downstream of the inlet 131. The sub-path junction 133 can be formed by interrupting the fin 11 that divides the flow path 12 before it reaches from the inlet 131 to the outlet 132. In a plan view from above, the sub-path junction 133 is the downstream end of the fin 11 that is interrupted before it reaches the outlet 132. At the sub-path junction 133, fluid is collected from multiple fluid paths 13, so the flow rate increases. As a result, stagnation of the fluid flow can be suppressed in the sub-path 13S that has a portion where the fluid flow is switched at an acute angle.

[0065] As shown in Fig. 7, in this embodiment, there is a junction region 30 where fluids that have passed through each of the sub-path junctions 133 gather. Upstream of the junction region 30, there are a first pre-junction flow path 12a, a second pre-junction flow path 12b, a third pre-junction flow path 12c, and a fourth pre-junction flow path 12d in the order according to the rotation direction RD. Downstream of the junction region 30, there are a first post-junction flow path 12e and a second post-junction flow path 12f in the order according to the rotation direction RD. That is, the number of flow paths 12 is reduced after the junction compared to before the junction. This makes it possible to suppress stagnation of the flow of the fluid due to a lack of flow rate.

[0066] The first pre-junction flow path 12a and the second pre-junction flow path 12b join together before joining the third pre-junction flow path 12c and the fourth pre-junction flow path 12d. That is, the fluid flowing through the first pre-junction flow path 12a joins with the fluid flowing through the second pre-junction flow path 12b, and then joins with the fluid flowing through the third pre-junction flow path 12c and the fourth pre-junction flow path 12d. The fluid flowing through the second pre-junction flow path 12b joins with the fluid flowing through the first pre-junction flow path 12a, and then joins with the fluid flowing through the third pre-junction flow path 12c and the fourth pre-junction flow path 12d.

[0067] However, the present invention is not limited to this, and may be configured such that, for example, the fluids flowing through the first pre-junction flow path 12a, the second pre-junction flow path 12b, the third pre-junction flow path 12c, and the fourth pre-junction flow path 12d are simultaneously joined. In this embodiment, the first pre-junction flow path 12a has a step in which the height of the flow path in the vertical direction increases from upstream to downstream. The step is caused, for example, by a component disposed on the lower surface 10c side of the main body 10. Due to this step, the flow of the fluid may be reduced in the first pre-junction flow path 12a. In this embodiment, the first pre-junction flow path 12a and the second pre-junction flow path 12b are joined at an early stage, so that the reduction in the flow of the fluid described above can be suppressed.

[0068] (2-4. Details of the main route) Fig. 8 is a diagram for explaining branching portions 134a to 134d and joining portions 135a to 135c in a main path 13M according to an embodiment of the present invention. Fig. 8 is a diagram showing a top view of the heat sink 1. In Fig. 8, a thick dashed line indicates the main path 13M.

[0069] As shown in FIG. 8, the main paths 13M include a first main path 13M1, a second main path 13M2, a third main path 13M3, a fourth main path 13M4, a fifth main path 13M5, a sixth main path 13M6, a seventh main path 13M7, an eighth main path 13M8, a ninth main path 13M9, a tenth main path 13M10, and an eleventh main path 13M11.

[0070] The first main path 13M1 is a fluid path from the fifth inlet 131e to the first outlet 132a. The second main path 13M2 is a fluid path from the fifth inlet 131e to the second outlet 132b. The third main path 13M3 is a fluid path from the sixth inlet 131f to the first outlet 132a. The fourth main path 13M4 is one of two fluid paths from the sixth inlet 131f to the second outlet 132b. The fifth main path 13M5 is the other of two fluid paths from the sixth inlet 131f to the second outlet 132b. In a plan view from above, the fourth main path 13M4 is located outward from the intersection CP relative to the fifth main path 13M5. Details of the inlet 131 and the outlet 132 are shown in FIG. 5.

[0071] The sixth main path 13M6 is a fluid path from the seventh inlet 131g to the third outlet 132c. The seventh main path 13M7 is a fluid path from the eighth inlet 131h to the fourth outlet 132d. The eighth main path 13M8 is a fluid path from the ninth inlet 131i to the fifth outlet 132e. The ninth main path 13M9 is a fluid path from the tenth inlet 131j to the sixth outlet 132f. The tenth main path 13M10 is a fluid path from the tenth inlet 131j to the seventh outlet 132g. The eleventh main path 13M11 is a fluid path from the eleventh inlet 131k to the seventh outlet 132g. Details of the inlet 131 and the outlet 132 are shown in FIG. 5.

[0072] At least some of the multiple main paths 13M have at least one of a branch portion and a junction portion. At the branch portion, the fluid path 13 is divided into at least two. At the junction portion, at least two fluid paths 13 are junctioned. The branch portion and the junction portion are generated at the ends of the fins 11 that form the flow paths 12 in a plan view from above.

[0073] 8, in this embodiment, some of the main paths 13M have at least one of branching portions 134a to 134d and merging portions 135a to 135c. The branching portions 134a to 134d and the merging portions 135a to 135c will be described in detail with reference to FIGS.

[0074] Fig. 9 is a diagram focusing on the third main path 13M3 and the fourth main path 13M4 shown in Fig. 8. As shown in Fig. 9, the third main path 13M3 has two branching portions 134a, 134b and one merging portion 135a. The fourth main path 13M4 has two branching portions 134a, 134b and two merging portions 135a, 135b.

[0075] The third main path 13M3 and the fourth main path 13M4 have a branching portion 134a that branches off from the fifth main path 13M5 downstream of the sixth inlet 131f. In other words, at least a portion of the multiple fluid paths 13 has a first branching portion 1341 that branches off from the first fluid path 13a downstream of the inlet 131. In the example shown in FIG. 9, the fifth main path 13M5 is the first fluid path 13a, and the number of the first fluid paths 13a is one. However, the number of the first fluid paths 13a may be multiple. Also, in the example shown in FIG. 9, the branching portion 134a is the first branching portion 1341.

[0076] The third main path 13M3 and the fourth main path 13M4 have a junction 135a where they join the first main path 13M1 and the second main path 13M2, which have the fifth inlet 131e as their inlet 131, downstream of the branching portion 134a. In other words, at least a part of the multiple fluid paths 13 has a first junction 1351 where they join the second fluid path 13b, which has a different inlet 131, downstream of the first branching portion 1341. In the example shown in FIG. 9, the first main path 13M1 and the second main path 13M2 are the second fluid paths 13b, and the number of the second fluid paths 13b is two. However, the number of the second fluid paths 13b may be one or three or more. In the example shown in FIG. 9, the junction 135a is the first junction 1351.

[0077] According to this embodiment, the cooling efficiency can be improved by increasing the number of flow paths 12 partitioned by the fins 11 using the first branching portion 1341. According to this embodiment, while improving the cooling efficiency, it is possible to suppress stagnation of the fluid flow due to the branching of the previous fluid path 13 at the first junction 1351 provided downstream of the first branching portion 1341.

[0078] Further, the third main path 13M3 and the fourth main path 13M4 further have a branch portion 134b that branches off the fluid path 13 downstream of the junction 135a. In other words, some of the multiple fluid paths 13 have a second branch portion 1342 that branches off the fluid path 13 downstream of the first junction 1351. In the example shown in FIG. 9, the branch portion 134b is the second branch portion 1342. The fluid path 13 branches off due to the second branch portion 1342. In detail, the third main path 13M3 and the fourth main path 13M4 are separated. In this embodiment, the number of the second branch portion 1342 is one, but the number of the second branch portion 1342 may be more than one.

[0079] According to this configuration, by providing the second branch portion 1342 that branches off the fluid path 13, the range in which the fluid flows can be expanded. This allows the cooling area in the heat sink 1 to be expanded. However, the second branch portion 1342 does not necessarily have to be provided. In this case, for example, the first main path 13M1 and the third main path 13M3 may not be provided.

[0080] Further, the third main path 13M3 further includes a junction 135b that joins with the fifth main path 13M5 that is separated from the branch 134a, in addition to the junction 135a. As described above, in the example shown in FIG. 9, the branch 134a is the first branch 1341, the junction 135a is the first junction 1351, and the fifth main path 13M5 is the first fluid path 13a. That is, some of the multiple fluid paths 13 further include a second junction 1352 that joins with the first fluid path 13a that is separated from the first branch 1341, in addition to the first junction 1351. In the example shown in FIG. 9, the junction 135b is the second junction 1352. According to this configuration, the second junction 1352 different from the first junction 1351 can also suppress stagnation of the flow of the fluid.

[0081] Fig. 10 is a diagram focusing on the first main path 13M1 and the second main path 13M2 shown in Fig. 8. As shown in Fig. 10, the first main path 13M1 has one branching portion 134b and one merging portion 135a. The second main path 13M2 has one branching portion 134b and two merging portions 135a and 135b.

[0082] Specifically, the first main path 13M1 and the second main path 13M2 join the third main path 13M3 and the fourth main path 13M4 at a joining portion 135a. The first main path 13M1 and the second main path 13M2 branch off at a branch portion 134b. The second main path 13M2 joins the fifth main path 13M5 at a joining portion 135b.

[0083] Here, attention is focused on the second main path 13M2. The second main path 13M2 has a branch portion 134b that branches off from the first main path 13M1 downstream of the fifth inlet 131e. That is, the branch portion 134b can be regarded as the above-mentioned first branch portion 1341. The branch portion 134b has the functions of the first branch portion 1341 and the second branch portion 1342. In the example shown in FIG. 10, the first main path 13M1 is the above-mentioned first fluid path 13a.

[0084] The second main path 13M2 has a fifth main path 13M5 having the sixth inlet 131f as its inlet 131 and a junction 135b that joins the fifth main path 13M5 downstream of a branching portion 134b that functions as a first branching portion 1341. That is, the junction 135b can be regarded as a first junction 1351. The junction 135b functions as the first junction 1351 and the second junction 1352. In this case, the fifth main path 13M5 is the above-mentioned second fluid path 13b.

[0085] In this embodiment, at least a part of the main path 13M has the first branching portion 1341 and the first merging portion 1351. As a result, even if the inlets 131 for the main path 13M, which tends to make the fluid path 13 long, are not provided in large numbers due to space restrictions, the first branching portion 1341 and the first merging portion 1351 are provided, so that the range in which the main path 13M is provided can be expanded while suppressing stagnation of the fluid flow. As a result, the cooling efficiency of the heat sink 1 can be improved.

[0086] The first branching portion 1341 and the first junction portion 1351 may be provided in the sub-path 13S and the auxiliary path 13A.

[0087] In this embodiment, at least a part of the long-distance path 13LD, which passes through the third region R3 and the second region R2 from the inlet 131 to the outlet 132 among the multiple fluid paths 13, has a first branching portion 1341 and a first merging portion 1351. In detail, the long-distance path 13LD is a fluid path 13 that passes through at least the third region R3, the second region R2, and the first region R1. The long-distance path 13LD may be a fluid path 13 that passes through the fourth region R4, the third region R3, the second region R2, and the first region R1.

[0088] In the present embodiment, the second main path 13M2, the third main path 13M3, and the fourth main path 13M4 have a first branch portion 1341 and a first junction portion 1351. The second main path 13M2, the third main path 13M3, and the fourth main path 13M4 are long-distance paths 13LD that pass through the fourth region R4, the third region R3, the second region R2, and the first region R1.

[0089] For the fluid flowing along the rotation direction RD of the fluid flow generating device 2, the long-distance path 13LD is prone to stagnation of the fluid flow because the distance from the inlet 131 to the outlet 132 is long. For this reason, in the conventional wisdom, it was not easy to configure a branching section by arranging fins 11 in the fluid path 13 in the long-distance path 13LD. However, in this embodiment, a first junction 1351 is provided to compensate for the stagnation of the fluid flow that may occur due to the provision of the first branching section 1341. For this reason, the fins 11 that configure a branching section can be arranged in the long-distance path 13LD as well, and the cooling efficiency can be improved.

[0090] In addition, the first branching portion 1341 and the first junction portion 1351 may be provided in the short-distance path 13SD that passes only through the second region R2 and the first region R1, or only through the first region R1. FIG. 11 is a diagram focusing on the tenth main path 13M10 shown in FIG. 8. As shown in FIG. 11, in this embodiment, the tenth main path 13M10, which is the short-distance path 13SD, has the first branching portion 1341 and the first junction portion 1351. In detail, the branching portion 134c is the first branching portion 1341. The ninth main path 13M9 is the first fluid path 13a. The junction portion 135c is the first junction portion 1351. One of the fluid paths 13 with the eleventh inlet 134k (see FIG. 5) as an inlet is the second fluid path 13b. The branch portion 134d is a second branch portion 1342 provided downstream of the first junction portion 1351.

[0091] In this embodiment, when the inlets 131 and the outlets 132 shared among the multiple fluid paths 13 are counted as one each, the number of the outlets 132 in the long-distance path 13LD is the same as the number of the inlets 131. In detail, the inlets 131 of the long-distance path 13LD include a fifth inlet 131e, a sixth inlet 131f, a seventh inlet 131g, an eighth inlet 131h, and a ninth inlet 131i (see FIG. 5), and the number of the inlets 131 of the long-distance path 13LD is five. The outlets 132 of the long-distance path 13LD include a first outlet 132a, a second outlet 132b, a third outlet 132c, a fourth outlet 132d, and a fifth outlet 132e (see FIG. 5), and the number of the outlets 132 of the long-distance path 13LD is also five. According to this configuration, it is possible to prevent the long-distance path 13LD from branching more than necessary, and to suppress stagnation of the flow of the fluid.

[0092] In this embodiment, at least a part of the long-distance path 13LD has an inlet 131 in the fourth region R4. In detail, the first main path 13M1, the second main path 13M2, the third main path 13M3, the fourth main path 13M4, and the fifth main path 13M5, which are part of the long-distance path 13LD, have the inlet 131 in the fourth region R4. This makes it possible to actively use the fourth region R4 as a passage for the fluid, thereby improving the cooling efficiency.

[0093] <3. Modifications> (3-1. First Modified Example) FIG. 12 is a plan view of the heat sink 1α of the first modification. FIG. 12 is a view of the heat sink 1α as seen from above. The heat sink 1α of the first modification also has fins 11α that divide a plurality of flow paths 12α on the upper surface 10aα of the main body 10α, as in the above embodiment. A plurality of fluid paths 13α are obtained by the plurality of flow paths 12α. The plurality of fluid paths 13α are divided into a main path 13Mα, a sub-path 13Sα, and an auxiliary path 13Aα. A plurality of the main path 13Mα, the sub-path 13Sα, and the auxiliary path 13Aα are provided. Note that in FIG. 12, only a portion of the plurality of fluid paths is indicated by thick lines.

[0094] In the first modified example, the fluid flows in the main path 13Mα in the same direction as the rotation direction RD of the fluid flow generating device 2. The sub-path 13Sα has a portion where the fluid flow direction switches from the rotation direction RD of the fluid flow generating device 2 to the opposite direction. The heat sink 1α of the first modified example has one Y-shaped fin 11bα, which is different from the above-mentioned embodiment. The Y-shaped fin 11bα arranged across the first region R1 and the fourth region R4 separates the sub-path 13Sα from the auxiliary path 13Aα.

[0095] Fig. 13 is a diagram illustrating details of the main path 13Mα in the heat sink 1α of the first modified example. As shown in Fig. 13, a part of the main path 13Mα has a first branching portion 1341α that constitutes a branching point with the first fluid path 13aα, and a first merging portion 1351α that is provided downstream of the first branching portion 1341α and constitutes a merging point with the second fluid path 13bα.

[0096] In the first modification, only a part of the long-distance path 13LDα passing through the fourth region R4, the third region R3, the second region R2, and the first region R1 has the first branch portion 1341α and the first junction 1351α. In the first modification, there is no main path 13Mα having a second branch portion downstream of the first junction 1351α. In the first modification, there is no main path 13Mα having a second junction portion that joins the first fluid path 13aα branched off at the first branch portion 1341α.

[0097] The inlets 131α and outlets 132α shared among multiple fluid paths 13α are counted as one each. In this case, in the first modification, the number of outlets 132α and the number of inlets 131α in the long-distance path 13LDα are both six, which is the same. The long-distance path 13LDα includes the fluid path 13α that passes through all four regions R1 to R4 and the fluid path 13α that passes through the third region R3, the second region R2, and the first region R1.

[0098] In the first modified example shown in Fig. 13, the long-distance path 13LDα is configured using a long-distance flow path 121α extending across the second region R2 and the third region R3. The upstream end of the long-distance flow path 121α may be located on the boundary between the third region R3 and the fourth region R4, may be located in the fourth region R4, or may be located in the third region R3. The downstream end of the long-distance flow path 121α is located in the first region R1.

[0099] In a plan view from above, the long-distance flow paths 121α are arranged in a direction away from the intersection point CP. Among the long-distance flow paths 121α, the outermost long-distance flow path 121aα located at the farthest position from the intersection point CP in the second region R2 has a junction portion 135aα that joins with other flow paths 12α in at least one of the second region R2 and the third region R3. In this modification, in detail, the outermost long-distance flow path 121aα has the junction portion 135aα in the third region R3. By providing the junction portion 135aα, it is possible to suppress stagnation of the flow of the fluid. Note that a similar junction portion 135a (see FIG. 8) is also present in the above embodiment.

[0100] (3-2. Second Modification) FIG. 14 is a plan view of the heat sink 1β of the second modified example. FIG. 14 is a view of the heat sink 1β as seen from above. The heat sink 1β of the second modified example also has fins 11β that divide a plurality of flow paths 12β on the upper surface 10aβ of the main body portion 10β, as in the above-described embodiment. A plurality of fluid paths 13β are obtained by the plurality of flow paths 12β. The plurality of fluid paths 13β are divided into a main path 13Mβ, a sub path 13Sβ, and an auxiliary path 13Aβ. A plurality of main paths 13Mβ, a sub path 13Sβ, and an auxiliary path 13Aβ are provided. Note that in FIG. 14, only a portion of the plurality of fluid paths 13β is indicated by thick lines.

[0101] In the second modified example, the main path 13Mβ also flows in the same direction as the rotation direction RD of the fluid flow generating device 2. The sub path 13Sβ has a portion where the fluid flow direction switches from the rotation direction RD of the fluid flow generating device 2 to the opposite direction. In the second modified example, as in the first modified example, one Y-shaped fin 11bβ is provided to separate the sub path 13Sβ and the auxiliary path 13Aβ.

[0102] Fig. 15 is a diagram illustrating details of the main path 13Mβ in the heat sink 1β of the second modified example. As shown in Fig. 15, a part of the main path 13Mβ has a first branching portion 1341β that constitutes a branching point with the first fluid path 13aβ, and a first merging portion 1351β that is provided downstream of the first branching portion 1341β and constitutes a merging point with the second fluid path 13bβ.

[0103] In the second modification, only a part of the long-distance path 13LDβ that passes through the fourth region R4, the third region R3, the second region R2, and the first region R1 has the first branch 1341β and the first junction 1351β. In the second modification, there is no main path 13Mβ that has a second branch downstream of the first junction 1351β.

[0104] In the second modified example, the main path 13Mβ having the first branch 1341β and the first junction 1351β has the second junction 1352β that joins the first fluid path 13aβ that is separated by the first branch 1341β. In the second modified example, there is a main path 13Mβ having a third branch 1343 that branches off the fluid path 13. There is no junction where the fluid joins before or after the third branch 1343. The main path 13Mβ having the third branch 1343 is a short-distance path 13SDβ that passes only through the second region R2 and the first region R1. In the short-distance path 13SDβ, fluid is less likely to stagnate than in the long-distance path 13LDβ, so it is easy to provide a branch without providing a junction.

[0105] The inlets 131β and the outlets 132β shared among multiple fluid paths 13β are each counted as one. In this case, in the second modified example, the number of outlets 132β in the long-distance path 13LDβ is less than the number of inlets 131β. In detail, the number of outlets 132β is four, and the number of inlets 131β is five. For this reason, in the long-distance path 13LDβ, it is possible to prevent the fluid path 13β from branching more than necessary, and to suppress stagnation of the fluid flow.

[0106] 15, the outermost long-distance flow passage 121aβ also has junctions 135aβ and 135bβ. In detail, the outermost long-distance flow passage 121aβ has junctions 135aβ and 135bβ that merge with other flow passages in the second region R2 and the third region R3.

[0107] <4. Points to note> Various technical features disclosed in this specification may be modified in various ways without departing from the spirit of the technical creation. Furthermore, multiple embodiments and modifications shown in this specification may be combined to the extent possible. [Industrial Applicability]

[0108] The present invention can be used in cooling devices configured for use in vehicles, home appliances, office equipment, and the like. [Explanation of symbols]

[0109] 1, 1α, 1β... heat sink 2. Fluid flow generating device 10, 10α, 10β... Main body 11, 11α, 11β...fin 12, 12α, 12β... flow path 13, 13α, 13β... Fluid path 121aα, 121aβ...Outermost long distance flow path 121α···Long distance flow path 13LD, 13LDα, 13LDβ...long-distance pathway 100...Cooling device 131, 131α, 131β...Entrance 132, 132α, 132β...exit 135aα, 135aβ, 135bβ...junction C...Central axis CP...intersection R1...1st area R2...Second area R3...Third area R4...4th area RD: Rotation direction

Claims

1. A heat sink used with a fluid flow generating device that generates a fluid flow by rotating about a central axis extending vertically, a main body having an upper surface facing the fluid flow generating device in a vertical direction; fins extending upward from the upper surface and defining a plurality of flow paths; having the upper surface includes a flat area that is free of the fins and faces the fluid flow generating device; the fins are disposed around the periphery of the flat region; When four regions defined by an X-axis and a Y-axis that intersect with each other at an intersection point between the central axis and the upper surface and extend in a direction in which the upper surface spreads are defined as a first region, a second region, a third region, and a fourth region in the order of being opposite to the rotation direction of the fluid flow generating device, Each of the plurality of fluid paths obtained from the plurality of flow paths includes: an inlet into which the fluid discharged from the fluid flow generating device flows; an outlet for discharging the fluid that has entered through the inlet to the outside; having The outlet of each of the plurality of fluid paths is provided in the first region, The plurality of fluid paths include a short path from the inlet to the outlet that passes through the second region and the first region; a long distance path passing through the third region, the second region, and the first region from the inlet to the outlet; Including, The long-distance path is configured using a long-distance flow path extending from the third region to the second region, In a plan view from above, the long-distance flow passages are arranged in a direction away from the intersection, A heat sink, wherein an outermost long-distance flow path among the plurality of long-distance flow paths, which is located at a location in the second region farthest from the intersection, has a junction portion in at least one of the second region and the third region where the outermost long-distance flow path merges with other flow paths.

2. The heat sink of claim 1 , wherein the fluid flow generator discharges fluid in a direction perpendicular to the vertical direction.

3. A heat sink according to claim 1 or 2; the fluid flow generating device; A cooling device having

4. the fluid is air; 4. The cooling device according to claim 3, wherein the fluid flow generating device is a centrifugal fan that takes in the air from above and discharges the air in a direction perpendicular to the up-down direction.

Images