Substrate structure and electronic device

Abstract

To increase a discharge flow rate of cooling air as compared with a case in which fins of a heat sink on the other side in a parallel direction have downstream-side tip positions in a flow direction located downstream in the flow direction from a tip position of a fin on one side in the parallel direction where a resistance part serving for resistance to discharge of the cooling air is present.SOLUTION: A substrate structure 70 has: a heat sink 100 which has a base part 110 where one surface 110A contacts an integrated circuit 62 fitted to an extension board 50 and a plurality of fins 120AA, AB, and B formed side by side in a parallel direction on the other surface 110B of the base part 110; a bracket 52 which is arranged downstream from the heat sink 100 and serves for resistance to discharge of cooling air R; and a raiser card 22 which is arranged downstream from the heat sink 100 and on one side and serves for resistance to the discharge of the cooling air R, and downstream-side tip positions 122AA, AB of fins 120AA, AB on the other side are located upstream from a tip position 122B of the fin 120B on the one side.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a substrate structure and an electronic device.

Background Art

[0002] Patent Document 1 and Patent Document 2 disclose a heat sink that is forced-air cooled by a cooling fan, and in particular, a technology related to a heat sink of an inverter device that converts AC power from a commercial power supply or the like into AC power of an arbitrary frequency and voltage and supplies power to an electric motor or the like.

[0003] In the technology of Patent Document 1, the tip position of the fins in the cooling air flow direction is such that the tip position of the fins located substantially in front of the cooling fan is positioned on the most upstream side, the tip positions of the fins on both sides in the width direction are positioned on the most downstream side, and inclined portions are provided on each fin so that the height from the base surface of the fin gradually increases from the tip position in the upstream side to the downstream side in the cooling air flow direction.

[0004] In the technology of Patent Document 2, on one surface of the base portion of the heat sink, heat-generating components are arranged, and on the other surface of the base portion, a plurality of fin portions and a component arrangement space are provided. In the side-end fin portion near this component arrangement space, an intake notch or an exhaust notch for intake or exhaust from the side surface is provided.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to increase the discharge flow rate of the cooling air discharged from the substrate as compared with a case where the tip position on the downstream side in the flow direction of the fins on the other side in the parallel direction in the heat sink is located on the downstream side in the flow direction from the tip position of the fins on one side in the parallel direction where there is a resistance portion that becomes a resistance to the discharge of the cooling air.

Means for Solving the Problems

[0007] A first aspect is a heat sink having a substrate to which a heat generating element is attached, a plate-shaped base portion having one surface in contact with the heat generating element, and a plurality of fins formed along the flow direction of the cooling air on the other surface of the base portion and arranged side by side in a parallel direction, a first resistance portion disposed on the downstream side in the flow direction with respect to the heat sink and serving as a resistance to the discharge of the cooling air, and a second resistance portion disposed on the downstream side in the flow direction and on one side in the parallel direction with respect to the heat sink and serving as a resistance to the discharge of the cooling air, wherein the tip position on the downstream side in the flow direction of the fins on the other side in the parallel direction is located on the upstream side in the flow direction from the tip position of the fins on one side, which is a substrate structure.

[0008] A second aspect is the substrate structure according to the first aspect, wherein the downstream end portion in the flow direction of the base portion of the heat sink has the other side in the parallel direction located on the upstream side in the flow direction from one side.

[0009] A third aspect is the substrate structure according to the second aspect, wherein a first heat generating component is attached to the downstream side with respect to the downstream end portion on the other side in the parallel direction of the base portion on the substrate.

[0010] A fourth aspect is the substrate structure according to any one of the first to fourth aspects, wherein the tip position of the fins disposed on the other side in the parallel direction in the heat sink is located on the upstream side in the flow direction stepwise or continuously toward the other side.

[0011] The fifth aspect is the substrate structure according to any one of the first to fourth aspects, wherein a second heat-generating component is attached upstream in the flow direction with respect to the upstream end in the flow direction on the other side in the parallel direction of the heat sink on the substrate.

[0012] The sixth aspect is the substrate structure according to any one of the first to fifth aspects, wherein the fins on the other side in the parallel direction in the heat sink are inclined toward the other side on the downstream side in the flow direction.

[0013] The seventh aspect is the substrate structure according to the sixth aspect, wherein the downstream side in the flow direction of the fins on one side in addition to the other side in the parallel direction in the heat sink is inclined toward the other side.

[0014] The eighth aspect is the substrate structure according to any one of the first to fifth aspects, wherein the fins on the other side in the parallel direction in the heat sink have a narrower interval on the downstream side than on the upstream side.

[0015] The ninth aspect is the substrate structure according to the eighth aspect, wherein the fins on the other side in the parallel direction in the heat sink are arranged obliquely toward the other side.

[0016] The tenth aspect is the substrate structure according to any one of the first to ninth aspects, wherein the other side in the parallel direction of the substrate is arranged above the one side in the direction of gravity.

[0017] The eleventh aspect is an electronic device to which the substrate structure according to any one of the first to tenth aspects is applied.

Advantages of the Invention

[0018] According to the substrate structure of the first aspect, the discharge flow rate of the cooling air discharged from the substrate increases as compared with the case where the tip position on the downstream side in the flow direction of the fins on the other side in the parallel direction in the heat sink is located downstream in the flow direction from the tip position of the fins on the one side in the parallel direction where there is a second resistance portion that becomes a resistance to the discharge of the cooling air.

[0019] According to the substrate structure of the second aspect, the discharge flow rate of the cooling air discharged from the substrate increases as compared with the case where the downstream end of the base portion of the heat sink is at the same position on the other side and one side in the parallel direction.

[0020] According to the substrate structure of the third aspect, the cooling effect of the first heat-generating component is improved as compared with the case where the first heat-generating component is arranged downstream of the downstream end of the other side of the base portion of the heat sink.

[0021] According to the substrate structure of the fourth aspect, the discharge flow rate of the cooling air increases as compared with the case where the tip position of the fins arranged on the other side in the parallel direction of the heat sink is located upstream in the flow direction toward one side.

[0022] According to the substrate structure of the fifth aspect, the cooling effect of the second heat-generating component is improved as compared with the case where the second heat-generating component is attached upstream of the upstream end of one side in the parallel direction of the heat sink.

[0023] According to the substrate structure of the sixth aspect, the discharge flow rate of the cooling air discharged from the substrate increases as compared with the case where the fins on the other side in the parallel direction of the heat sink are straight along the flow direction.

[0024] According to the substrate structure of the seventh aspect, the discharge amount of the cooling air discharged from the substrate increases as compared with the case where only the fins on the other side in the parallel direction of the heat sink are inclined toward the other side on the downstream side.

[0025] According to the substrate structure of the eighth aspect, the discharge flow rate of the cooling air discharged from the substrate increases as compared with the case where the interval between the downstream sides of the fins on the other side in the parallel direction of the heat sink is wider than the interval on the upstream side.

[0026] According to the substrate structure of the ninth aspect, the discharge flow rate of the cooling air discharged from the substrate increases as compared with the case where the fins on the other side in the parallel direction of the heat sink are arranged obliquely toward one side.

[0027] According to the substrate structure of the tenth aspect, the discharge flow rate of the cooling air discharged from the substrate increases as compared with the case where one side in the parallel direction of the substrate is arranged above the other side in the gravitational direction.

[0028] According to the substrate structure of the eleventh aspect, the cooling effect by the cooling air discharged from the substrate is improved as compared with the case where the tip position on the upstream side in the flow direction of the fins on the other side in the parallel direction in the heat sink is located downstream in the flow direction from the tip position of the fins on one side in the parallel direction where there is a second resistance portion that becomes a resistance to the discharge of the cooling air.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0030] <Embodiment> An electronic device to which a substrate structure according to an embodiment of the present invention is applied will be described.

[0031] [Electronic Device] First, the overall configuration of the electronic device will be described. Here, two orthogonal horizontal directions are defined as the X direction and the Y direction, which are indicated by arrows X and Y, respectively. The vertical direction orthogonal to the X direction and the Y direction is defined as the Z direction, which is indicated by arrow Z. Further, the flow direction in which the cooling air described later flows is indicated by arrow K.

[0032] As shown in FIG. 6, the electronic device 10 of the present embodiment is a server having an image processing function, but is not limited thereto.

[0033] Inside the housing 12 of the electronic device 10, a motherboard 20, fans 30, 32, and a power supply (not shown) are provided. The motherboard 20 is the main electronic circuit board in the present electronic device 10. Also, the inside of the housing 12 of the electronic device 10 is cooled by the cooling air R generated by the fans 30, 32.

[0034] An expansion board 50 (see also FIG. 2) is attached to the motherboard 20. In the present embodiment, the expansion board 50 is attached to the motherboard 20 via a riser card 22. Specifically, an insertion portion 54 (see also FIG. 2) formed on the lower side in the vertical direction of the expansion board 50 is inserted into an expansion slot 24 provided on the riser card 22 attached to the motherboard 20.

[0035] The expansion board 50 is fixed to the housing 12 by attaching a sheet metal bracket 52 provided at the end to the housing 12 with screws or the like.

[0036] In the present embodiment, the expansion board 50 has its board surface arranged along the vertical direction. Also, the fans 30, 32 are provided on the right side in FIG. 1, which is one side in the X direction with respect to the expansion board 50. Therefore, the flow direction K of the cooling air R is a direction from the right side to the left side in FIG. 1.

[0037] As shown in FIG. 2, a plurality of elements are attached to the expansion board 50. Also, an integrated circuit 60, which is an example of a heat-generating element, is attached to the central portion of the expansion board 50. The integrated circuit 60 in the present embodiment is an FPGA (field-programmable gate array), but is not limited thereto.

[0038] In addition, a heat sink 100 (see also FIG. 1) is attached to the extension board 50. The heat sink 100 is made of a metal material with good heat transfer characteristics such as aluminum, iron, and copper. In this embodiment, the heat sink 100 is fixed to the extension board 50 with a plurality of screws 90.

[0039] As shown in FIGS. 1 and 2, the heat sink 100 has a plate-shaped base portion 110 and a plurality of fins 120AA, 120AB, 120B.

[0040] As shown in FIG. 2, one surface 110A (see FIG. 1) of the base portion 110 of the heat sink 100 is in contact with the aforementioned integrated circuit 60. In addition, a plurality of fins 120AA, 120AB, 120B are formed on the other surface 1100B of the base portion 110.

[0041] Note that in this embodiment, one surface 110A (see FIG. 1) of the base portion 110 is in contact with the integrated circuit 60 via a thermal sheet, but it is not limited thereto. For example, grease may be applied to the integrated circuit 60 or the base portion 110.

[0042] As shown in FIGS. 1 and 2, the plurality of fins 120AA, 120AB, 120B are arranged in parallel. The parallel direction in which the plurality of fins 120AA, 120AB, 120B are arranged in parallel in this embodiment is the vertical direction (Z direction) (see FIGS. 2 and 6). In other words, the thickness direction of the base portion 110 of the heat sink 100 is the Y direction. Also, the lower side in the vertical direction is taken as one side of the parallel direction, and the upper side is taken as the other side of the parallel direction.

[0043] Note that although the fins 120AA, 120AB, and 120B have different lengths as will be described later, their other specifications are the same. Also, when there is no need to distinguish them, the AA, AB, and B after the reference numeral may be omitted and they may be described as fins 120.

[0044] The fins 120 have their thickness directions in the parallel direction (vertical direction), and their plate surfaces are formed along the flow direction K of the cooling air R (see FIG. 6). Note that the fins 120 do not necessarily have to completely coincide with the flow direction K. It is sufficient if the cooling air R (see FIG. 6) flows from the right side to the left side in FIG. 2, which is the flow direction K.

[0045] As described above, as shown in FIG. 1, a bracket 52 is provided on the downstream side of the flow direction K with respect to the extension board 50. This bracket 52 serves as a resistance to the discharge of the cooling air R to the downstream side (left side in the figure) of the extension board 50. In this embodiment, this bracket 52 is an example of the first resistance portion.

[0046] Also, a riser card 22 is arranged on one side (lower side) in the parallel direction (vertical direction) with respect to the extension board 50. This riser card 22 serves as a resistance to the discharge of the cooling air R on one side (lower side) in the parallel direction (vertical direction). In this embodiment, this riser card 22 is an example of the second resistance portion.

[0047] Here, the substrate structure 70 of this embodiment includes an extension board 50, a heat sink 100 having a plate-shaped base portion 110 and a plurality of fins 120AA, 120AB, 120B, a bracket 52 that serves as a resistance to the discharge of the cooling air R, and a riser card 22 that serves as a resistance to the discharge of the cooling air R.

[0048] Then, as shown in FIGS. 1 and 2, the tip positions 122AA, 122AB on the downstream side of the flow direction K of the fins 120AA, 120AB on the other side (upper side) in the parallel direction (vertical direction) of the heat sink 100 are located on the upstream side (right side in FIG. 2) of the flow direction K from the tip position 122B of the fins 120B on one side (lower side).

[0049] Further, the tip positions 122AA and 112B of the fins 120AA and 120AB arranged on the other side in the parallel direction are located stepwise on the upstream side in the flow direction toward the other side. Specifically, the tip positions 122AB of the two fins 120AB on the other side (upper side) in the parallel direction (vertical direction) are located further upstream than the tip position 122AA of the fins 120AA on one side.

[0050] Also, the downstream end 112 of the heat sink 100 in the base portion 110 in the flow direction K is such that the other end 112B in the parallel direction is located upstream in the flow direction than the one end 112A. Explaining from another perspective, a notch 113 that is cut out in a rectangular shape is formed at the other corner on the downstream side of the base portion 110 of the heat sink 100. Note that a screw hole 92 for a screw 90 (see FIG. 2) is formed in a portion 111 between the other end 112B of the base portion 110 of the heat sink 100 and the fin 120AB.

[0051] An extension portion 117 extending upstream is formed at the other end (upper end) in the parallel direction of the upstream end 116 of the base portion 110 of the heat sink 100 in the flow direction K, and a screw hole 92 for a screw 90 (see FIG. 2) is formed here. Also, two of the fins 120B on one side in the parallel direction have a short upstream side in the flow direction K of the base portion 110 of the heat sink 100, and the intermediate portion in the flow direction K is interrupted. And screw holes 92 for a screw 90 (see FIG. 2) are formed in portions 118 and 119 where these fins 120B are not formed.

[0052] As shown in FIGS. 2 and 6, a power semiconductor element 62 such as a power transistor is attached to the downstream side of the other end 112B of the downstream end 112 of the base portion 110 of the heat sink 100 in the extension board 50. Explaining from another perspective, the power semiconductor element 62 is attached to the notch 113 of the base portion 110 of the heat sink 100 in the extension board 50. Note that the power semiconductor element 62 is an example of a first heat generating component.

[0053] On the upstream side of the other end 116A of the upstream end 116 of the base portion 110 of the heat sink 100 in the expansion board 50, a power connector 64 is provided. From another perspective, on the upstream side of the upstream end 116 of the base portion 110 of the heat sink 100 in the expansion board 50, the power connector 64, connectors 65, and 66 are arranged side by side, and the power connector 64 is provided on the outermost side of these three connectors. Note that the power connector 64 is an example of a second heat-generating component.

[0054] [Operation] Next, the operation of this embodiment will be described.

[0055] As shown in FIG. 6, the heat of the integrated circuit 60 on the expansion board 50 is transferred to the heat sink 100, and when the cooling air R generated by the fans 30 and 32 flows through the heat sink 100 (see arrows R1 and R2), it is mainly dissipated by the fins 120. Thereby, the integrated circuit 60 is cooled.

[0056] On the downstream side in the flow direction K with respect to the expansion board 50, a bracket 52 is arranged. Since this bracket 52 becomes a resistance to the discharge of the cooling air R to the downstream side of the expansion board 50, the cooling air R that has flowed through the heat sink 100 is not discharged to the downstream side or the discharge flow rate is small. Therefore, the non-discharged cooling air R flows in the parallel direction, which is the vertical direction in this embodiment. Note that in this embodiment, the housing 12 also becomes a resistance to the discharge of the cooling air R.

[0057] On one side (lower side) in the parallel direction with respect to the expansion board 50, a riser card 22 is arranged. Since this riser card 22 becomes a resistance to the discharge of the cooling air R, the discharge flow rate to one side (lower side) is small (see arrow R4).

[0058] On the other side (upper side) in the parallel direction with respect to the expansion board 50, there is no or almost no resistance to discharge, so the discharge flow rate to the other side (upper side) increases (see arrow R3).

[0059] Here, according to the substrate structure 70 of the present embodiment, the tip positions 122AA and 120AB on the downstream side in the flow direction of the fins 120AA and 120AB on the other side in the parallel direction in the heat sink 100 are located upstream of the tip position 122B of the fin 120B on one side in the parallel direction in the flow direction.

[0060] Therefore, the open area on the other side (upper side) of the heat sink 100 increases. Also, as shown by the arrow R5, the flow of the cooling air R is directed toward the other side. Accordingly, the discharge flow rate of the cooling air R discharged from the expansion board 50 to the other side is larger than the case where the tip positions 122AA and 122AB of the fins 120AA and 120AB on the other side are located downstream of the tip position 122B of the fin 120B on one side. Note that the numbers of the arrows R3 and R4 in FIG. 6 represent the magnitudes of the discharge flow rates.

[0061] In addition, since the discharge flow rate of the cooling air R discharged from the expansion board 50 to the other side (see arrow R3) increases, the flow velocity of the cooling air R flowing through the heat sink 100, particularly the wind speed of the cooling air R1 on the other side, increases.

[0062] In this way, since the discharge flow rate of the cooling air R discharged from the expansion board 50 increases and the wind speed increases, the cooling effect of the integrated circuit 60 is enhanced and the temperature rise of the integrated circuit 60 is suppressed. Explaining from another perspective, the temperature rise of the integrated circuit 60 is suppressed more than the case where the tip positions 122AA and 120AB of the fins 120AA and 120AB on the other side are located downstream of the tip position 122B of the fin 120B on one side.

[0063] Further, in the present embodiment, the tip position 122AB of the fin 120AB is located further upstream than the tip position 122AA of the fin 120AA arranged on the other side in the parallel direction in the heat sink 100. Therefore, the open area on the other side (upper side) of the heat sink 100 becomes even larger and the flow of the cooling air R is further directed toward the other side (see arrow R5). Accordingly, the discharge flow rate of the cooling air R discharged from the expansion board 50 increases.

[0064] Further, the other end portion 112B in the parallel direction at the downstream end portion 112 in the flow direction K of the base portion 110 of the heat sink 100 of the present embodiment is located upstream in the flow direction from the one end portion 112A. Therefore, compared with the case where the downstream end portion 112 of the base portion 110 of the heat sink 100 is at the same position on the other side and the one side in the parallel direction, the discharge flow rate of the cooling air R discharged from the extension board 50 increases.

[0065] Also, in the present embodiment, a power semiconductor element 62 is attached to the downstream side with respect to the other end portion 112B in the parallel direction of the downstream end portion 112 of the base portion 110 of the heat sink 100 on the extension board 50. Since the fast cooling air R1 hits this power semiconductor element 62, a high cooling effect can be obtained. Therefore, compared with the case where the power semiconductor element 62 is attached to the downstream side with respect to the other end portion 112B in the parallel direction of the downstream end portion 112, the cooling effect of the power semiconductor element 62 is improved.

[0066] Also, in the present embodiment, a power connector 64 is provided on the upstream side with respect to the other end portion 116A in the parallel direction of the upstream end portion 116 of the base portion 110 of the heat sink 100 on the extension board 50. Since the fast cooling air R1 hits this power connector 64, a high cooling effect can be obtained. Therefore, compared with the case where the power connector 64 is attached to the downstream side with respect to the one end portion in the parallel direction of the upstream end portion 116, the cooling effect of the power connector 64 is improved.

[0067] Also, in the present embodiment, the extension board 50 is arranged with the parallel direction along the vertical direction, and the other side in the parallel direction is arranged on the upper side in the direction of gravity. The cooling air R that has been warmed by passing through the heat sink 100 and has a relatively small specific gravity tends to flow upward, that is, to the other side.

[0068] Therefore, compared with the case where the other side in the parallel direction of the extension board 50 is arranged on the lower side in the direction of gravity, the discharge flow rate of the cooling air R discharged from the extension board 50 increases.

[0069] <Modification Example of Heat Sink> Next, a modification example of the heat sink will be described. The same members as those of the heat sink 100 in the above embodiment are denoted by the same reference numerals, and redundant descriptions are omitted or simplified.

[0070] [First Modification Example] The heat sink 200 of the first modification example shown in FIG. 3 has a plate-like base portion 110 and a plurality of fins 120B and 220. The plurality of fins 120B and 220 are arranged side by side in parallel. Note that since the fins 120B on one side in the parallel direction are the same as those in the embodiment, the description thereof is omitted.

[0071] The tip position 224 on the downstream side in the flow direction K of the fins 220 on the other side (upper side) in the parallel direction (vertical direction) is located on the upstream side in the flow direction K from the tip position 122B of the fins 120B on one side (lower side).

[0072] For the fins 220 on the other side in the parallel direction, the downstream portion 222 in the flow direction K is inclined toward the other side. Also, the tip position 224 of the fins 220 on the other side is located on the upstream side as it goes toward the other side. From another perspective, the tip position 224 of the fins 220 on the other side is continuously located on the upstream side as it goes toward the other side.

[0073] (Function) Next, the function of this modification example will be described.

[0074] In the heat sink 200 of this modification example, for the fins 220 on the other side in the parallel direction, the downstream portion 222 in the flow direction K is inclined toward the other side.

[0075] Therefore, the flow of the cooling air flowing through the fins 220 on the other side of the heat sink 100 further faces the other side (see arrow R5 in FIG. 6). Therefore, compared with the case where the fins 220 on the other side in the parallel direction in the heat sink 200 are straight along the flow direction K, the discharge flow rate of the cooling air discharged from the extension board 50 increases (see arrow R3 in FIG. 6). In other words, compared with the case where the downstream portion 222 of the fins 220 is not inclined, the discharge flow rate of the cooling air discharged from the extension board 50 increases (see arrow R3 in FIG. 6).

[0076] Also, the tip position 224 of the fins 220 on the other side is located upstream of the tip position 122B of the fins 120B, and the tip position 224 of the fins 220 on the other side is located upstream as it faces the other side. Therefore, the flow of the cooling air flowing through the fins 220 on the other side of the heat sink 100 further faces the other side, and the discharge flow rate of the cooling air increases (see arrow R3 in FIG. 6).

[0077] And since the discharge flow rate of the cooling air discharged from the extension board 50 thus further increases, the cooling effect of the integrated circuit 60 becomes higher.

[0078] [Second Modified Example] The heat sink 300 of the second modified example shown in FIG. 4 has a plate-shaped base portion 110 and a plurality of fins 320, 220. Since the fins 220 on the other side in the parallel direction are the same as those in the first modified example, the description thereof is omitted.

[0079] The tip position 224 on the downstream side in the flow direction K of the fins 220 on the other side (upper side) in the parallel direction (vertical direction) is located upstream of the tip position 324 of the fins 320 on one side (lower side) in the flow direction K.

[0080] The fins 320 on one side in the parallel direction have the downstream portion 322 in the flow direction K inclined toward the other side. The positions of the tip positions 324 of the fins 320 on one side are the same, but the two fins 320A on the other side

[0081] Also, the tip position 324 of the fin 320 on the other side is located upstream as it goes toward the other side. Explaining from another perspective, the tip position 324 of the fin 320 on the other side is continuously located upstream as it goes toward the other side.

[0082] (Function) Next, the function of this modified example will be described.

[0083] In the heat sink 300 of this modified example, for the fin 320 on one side in the parallel direction, the downstream part 322 in the flow direction K is inclined toward the other side. Therefore, the flow of the cooling air flowing through the fin 320 on one side of the heat sink 100 further turns toward the other side (see arrow R5 in FIG. 6). Accordingly, compared with the case where only the fin 220 on the other side in the parallel direction in the heat sink 300 is straight along the flow direction K, the discharge flow rate of the cooling air discharged from the expansion board 50 increases (see arrow R3 in FIG. 6).

[0084] [Third Modified Example] The heat sink 400 of the third modified example shown in FIG. 5 has a plate-like base portion 110 and a plurality of fins 120B, 420A, 420B. The plurality of fins 120B, 420A, 420B are arranged in parallel. Note that since the fin 120B on one side in the parallel direction is the same as that in the embodiment, the description thereof is omitted.

[0085] The fins 420A, 420B on the other side in the parallel direction are each inclined toward the other side in the parallel direction as a whole, and the downstream tip positions 422A, 422B are located on the other side in the parallel direction than the upstream rear end positions 423A, 423B. Also, thereby, the interval in the parallel direction between the tip positions 422A, 422B of the fins 420A, 420B on the other side is narrower than the interval in the parallel direction of the rear end positions 423A, 423B.

[0086] The downstream tip positions 422AA, 422AB in the flow direction K of the fins 420A, 420B on the other side in the parallel direction are located upstream in the flow direction K than the tip position 122B of the fin 120B on one side (lower side).

[0087] Also, the tip position 422B of the fin 420B arranged on the other side in the parallel direction is located further upstream than the tip position 422A of the fin 420A on one side thereof.

[0088] (Function) Next, the function of this modification will be described.

[0089] The fins 420A and 420B on the other side in the parallel direction are each inclined entirely toward the other side in the parallel direction, and the interval in the parallel direction between the tip positions 422A and 422B of the fins 420A and 420B on the other side is narrower than the interval in the parallel direction between the rear end positions 423A and 423B. Therefore, the wind speed of the flowing cooling air R1 (see FIG. 6) discharged from between the fins 420A and 420B on the other side becomes even faster.

[0090] Therefore, compared with the case where the interval on the downstream side between the fins 420A and 420B on the other side in the parallel direction of the heat sink 400 is wider than the interval on the upstream side, the discharge flow rate of the cooling air discharged from the expansion board 50 increases (see arrow R3 in FIG. 6).

[0091] Also, as described above, the fins 420A and 420B on the other side in the parallel direction are each inclined entirely toward the other side in the parallel direction, and the flow of the cooling air further faces the other side (see arrow 5 in FIG. 6).

[0092] Therefore, compared with the case where the fins 420A and 420B on the other side in the parallel direction of the heat sink 400 are arranged obliquely toward one side, the discharge flow rate of the cooling air discharged from the expansion board 50 increases (see arrow R3 in FIG. 6).

[0093] <Others> Note that the present invention is not limited to the above-described embodiments and modifications.

[0094] For example, in the above-described embodiments and modified examples, although the extension board 50 and the base portions 110 of the heat sinks 100, 200, 300, and 400 are arranged with their plate surfaces along the vertical direction, the present invention is not limited thereto. The extension board 50 and the base portion 110 may be arranged along the horizontal direction or may be arranged obliquely with respect to the horizontal.

[0095] Also, for example, in the above-described embodiments and modified examples, although the fans 30 and 32 are provided outside the extension board 50 in the X direction and generate the cooling air R from the right side to the left side in the figure, the present invention is not limited thereto. The fan may be located anywhere and may be above, below, or on the back side of the extension board, etc. In that case, the cooling air R may be passed through the heat sink using a duct or the like.

[0096] Also, for example, in the above-described embodiments and modified examples, although an example of the first resistance portion is the bracket 52, the present invention is not limited thereto. The first resistance portion may be a component or member that is downstream of the heat sink such as a housing, a frame, a sub-board, and components provided on the board and that provides resistance to the discharge of the cooling air to the downstream side.

[0097] Also, for example, in the above-described embodiments and modified examples, although an example of the second resistance portion is the riser card 22, the present invention is not limited thereto. The second resistance portion may be a component or member that is downstream and on one side of the heat sink such as a housing, a frame, a bracket, and components provided on the board and that provides resistance to the discharge of the cooling air to the other side.

[0098] Also, for example, in the above-described embodiments and modified examples, although an example of the board is the extension board, the present invention is not limited thereto. A board other than the extension board, for example, a motherboard, may be used.

[0099] Also, for example, in the above embodiments and variations, an example of the heating element was the integrated circuit 60, but it is not limited thereto. The heating element may be any element that generates heat when energized, and for example, it may be a Central Processing Unit.

Explanation of Reference Numerals

[0100] 10 Electronic device 22 Riser card (an example of the second resistance part) 50 Expansion board (an example of the substrate) 52 Bracket (an example of the first resistance part) 60 Integrated circuit (an example of the heating element) 62 Power semiconductor element (an example of the first heat generating component) 64 Power connector (an example of the second heat generating component) 70 Substrate structure 100 Heat sink 110 Base part 110A One surface 112 Downstream end 112A One side end 112B The other side end 116 Upstream end 116A The other side end 120AA Fin 120AB Fin 120B Fin 122AA Tip position 122AB Tip position 122B Tip position 200 Heat sink 220 Fin 222 Downstream part 224 Tip position 300 Heat sink 320 Fin 320A Fin 322 Downstream part 324 Tip position 400 Heat sink 420A Fin 420B Fin Tip position of 422A Tip position of 422B Rear end position of 423A Flow direction of K Cooling air of R

Claims

1. a substrate to which a heating element is attached; a plate-shaped base portion having one surface in contact with the heating element; and a heat sink having a plurality of fins formed along the flow direction of the cooling air and arranged side by side in the parallel direction on the other surface of the base portion; a first resistance portion disposed on the downstream side of the heat sink in the flow direction, which serves as a resistance to the discharge of the cooling air flowing downstream in the flow direction; a second resistance portion disposed on the downstream side of the heat sink in the flow direction and on one side in the parallel direction, which serves as a resistance to the discharge of the cooling air flowing on one side in the parallel direction due to the resistance of the first resistance portion; characterized by comprising; the tip position on the downstream side in the flow direction of the fins on the other side in the parallel direction is located upstream in the flow direction from the tip position of the fins on one side in the parallel direction, a substrate structure.

2. the downstream end portion of the base portion of the heat sink in the flow direction has the other side in the parallel direction located upstream in the flow direction than the one side, the substrate structure according to claim 1.

3. a first heat-generating component is attached downstream of the downstream end portion of the base portion of the substrate on the other side in the parallel direction, the substrate structure according to claim 2.

4. the tip position of the fins disposed on the other side in the parallel direction of the heat sink is located upstream in the flow direction stepwise or continuously toward the other side, the substrate structure according to any one of claims 1 to 3.

5. a second heat-generating component is attached upstream of the upstream end portion of the heat sink on the other side in the parallel direction of the substrate in the flow direction, the substrate structure according to any one of claims 1 to 4.

6. the fins on the other side in the parallel direction of the heat sink have the downstream side inclined toward the other side in the flow direction, the substrate structure according to any one of claims 1 to 5.

7. in addition to the other side in the parallel direction of the heat sink, the downstream side of the fins on one side is inclined toward the other side, the substrate structure according to claim 6.

8. the fins on the other side in the parallel direction of the heat sink have the downstream interval narrower than the upstream interval, the substrate structure according to any one of claims 1 to 5.

9. The fins on the other side in the parallel direction in the heat sink are arranged obliquely toward the other side. The substrate structure according to claim 8.

10. The other side in the parallel direction of the substrate is arranged above the one side in the direction of gravity. The substrate structure according to any one of claims 1 to 9.

11. An electronic device to which the substrate structure according to any one of claims 1 to 10 is applied.

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