Heat dissipation materials

Abstract

To provide a heat dissipation member which prevents a pressure loss while suppressing temperature difference between heat generators.SOLUTION: A heat dissipation member 1 comprises: a tabular base part 2 which extends in a first direction along a flow direction of a coolant and also in a second direction perpendicular to the first direction, and has a thickness in a third direction perpendicular to the first direction and the second direction; and at least one fin group 3A to 3C respectively made up of a plurality of pin fins 30A to 30C protruding in a columnar shape from the base part 2 to one side in the third direction. Here, a surface area with which the coolant can come into contact is defined as the surface area of each of the pin fins. Then, the surface area of the pin fins disposed at least in one region is larger than the surface areas of the pin fins in other regions.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a heat dissipation member. [Background technology]

[0002] Conventionally, a liquid cooling jacket is used to cool a heat generating body. The liquid cooling jacket has a sealing body. The sealing body has a plate-shaped main body and a plurality of pin fins. The plurality of pin fins protrude from the main body. When a fluid flows between adjacent ones of the plurality of pin fins, heat from the heat generating body is transferred to the fluid (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-1051 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, in a liquid cooling jacket, when multiple heat generating elements are arranged in the direction of fluid flow, there are problems with the temperature difference that occurs between the heat generating elements and the pressure loss due to the pin fins.

[0005] In view of the above circumstances, an object of the present disclosure is to provide a heat dissipation member that can suppress pressure loss while suppressing the temperature difference between heating elements. [Means for solving the problem]

[0006] An exemplary heat dissipation member of the present disclosure has a plate-shaped base portion that extends in a first direction along the direction in which a refrigerant flows and in a second direction perpendicular to the first direction and has a thickness in a third direction perpendicular to the first and second directions, and at least one fin group consisting of a plurality of pin fins that protrude in a columnar shape from the base portion to one side in the third direction. The surface area of ​​the pin fins that can come into contact with the refrigerant is defined as the surface area of ​​the pin fins, and the surface area of ​​the pin fins arranged in at least one region is larger than the surface area of ​​the pin fins arranged in another region. Effect of the Invention

[0007] According to the exemplary heat dissipation member of the present disclosure, it is possible to suppress the pressure loss while suppressing the temperature difference between the heat generating bodies. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing the configuration of a heat dissipation member according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing a configuration of a heat dissipation member according to a modified example of the first embodiment. [Diagram 3] FIG. 3 is a schematic diagram showing an example of a pin fin formed as a square pillar. [Figure 4] FIG. 4 is a schematic diagram showing an example of a pin fin formed in a truncated cone shape. [Diagram 5] FIG. 5 is a schematic diagram showing an example of a pin fin formed as a semi-cylinder. [Figure 6] FIG. 6 is a diagram showing a configuration of a heat dissipation member according to a modified example of the first embodiment. [Figure 7] FIG. 7 is a diagram showing an example in which the pin fin and the base portion are formed as an integrated member. [Figure 8] FIG. 8 is a diagram showing an example in which the pin fins and the base portion are formed as separate members. [Figure 9] FIG. 9 is a diagram showing an example of the configuration between adjacent fin groups. [Figure 10] FIG. 10 is a diagram showing the configuration of a heat dissipation member according to the second embodiment. [Figure 11] FIG. 11 is a diagram showing a configuration of a heat dissipation member according to a modified example of the second embodiment. [Figure 12] FIG. 12 is a diagram showing the configuration of a heat dissipation member according to the third embodiment. [Figure 13] FIG. 13 is a schematic diagram showing an example of a pin fin having projections and recesses formed on the surface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Exemplary embodiments of the present disclosure will now be described with reference to the drawings.

[0010] In the drawings, the first direction is the X direction, X1 is one side of the first direction, and X2 is the other side of the first direction. The first direction is along the direction F in which the refrigerant W flows, and the downstream side is F1 and the upstream side is F2. The second direction perpendicular to the first direction is the Y direction, and Y1 is one side of the second direction and Y2 is the other side of the second direction. The third direction perpendicular to the first and second directions is the Z direction, and Z1 is one side of the third direction and Z2 is the other side of the third direction. The above perpendicular includes an intersection at an angle slightly deviated from 90 degrees. The above directions do not limit the direction when the heat dissipation member 1 is incorporated into various devices. The number, size, and arrangement of pin fins, which will be described later, shown in the drawings are merely examples.

[0011] <1. First embodiment> Fig. 1 is a diagram showing a configuration of a heat dissipation member 1 according to a first embodiment of the present disclosure. The upper part in Fig. 1 is a plan view of the heat dissipation member 1 as viewed from one side in the third direction, and the lower part in Fig. 1 is a side view of the heat dissipation member 1 as viewed from one side in the second direction.

[0012] The heat dissipation member 1 is a device for cooling a plurality of heat generating elements 4A, 4B, and 4C arranged in a first direction. The heat generating elements 4A, 4B, and 4C are, for example, power transistors of an inverter provided in a traction motor for driving wheels of a vehicle. The power transistor is, for example, an IGBT (Insulated Gate Bipolar Transistor). In this case, the heat dissipation member 1 is mounted on the traction motor. Note that the number of heat generating elements may be any number other than three.

[0013] Heat dissipation member 1 has a base portion 2 and a heat dissipation fin portion 10. Heat dissipation fin portion 10 has an upstream fin group 3A, a central fin group 3B, and a downstream fin group 3C.

[0014] The base portion 2 has a plate shape that extends in a first direction and a second direction and has a thickness in a third direction. The base portion 2 is made of a metal having high thermal conductivity, for example, a copper plate.

[0015] The upstream fin group 3A, the central fin group 3B, and the downstream fin group 3C are arranged in this order on one side of the third direction of the base portion 2, from the other side in the first direction (upstream side) to one side in the first direction (downstream side).

[0016] The upstream fin group 3A, the central fin group 3B, and the downstream fin group 3C are each composed of a plurality of pin fins 30A, 30B, and 30C. The pin fins 30A, 30B, and 30C protrude in a columnar shape toward one side in the third direction from one side surface 21 in the third direction of the base portion 2. The pin fins 30A, 30B, and 30C are cylindrical and extend in the third direction. The pin fins 30A, 30B, and 30C are arranged in regions RA, RB, and RC of the base portion 2, respectively.

[0017] In each of the regions RA, RB, and RC, rows of pin fins 30A, 30B, and 30C aligned in the second direction are arranged side by side in the first direction.

[0018] That is, the heat dissipation member 1 has at least one fin group 3A, 3B, 3C composed of a plurality of pin fins 30A, 30B, 30C protruding in a columnar shape on one side in the third direction from the base portion 2. The number of fin groups may be two, four or more, or may be one.

[0019] The heat generating elements 4A, 4B, 4C are in direct or indirect contact with the other side surface 22 in the third direction of the base portion 2. When viewed in the third direction, the heat generating elements 4A, 4B, 4C overlap with the fin groups 3A, 3B, 3C, respectively (the dashed line in the upper part of FIG. 1).

[0020] Coolant W is supplied to the upstream fin group 3A from the upstream side of the upstream fin group 3A, so that the coolant W flows through the fin groups 3A, 3B, and 3C in order, and is discharged downstream from the downstream fin group 3C. At this time, heat generated from the heat generating elements 4A, 4B, and 4C is transferred to the coolant W via the base portion 2 and the fin groups 3A, 3B, and 3C, respectively. This cools the heat generating elements 4A, 4B, and 4C. The heat dissipating member 1 is attached to a water jacket (not shown). The water jacket covers the heat dissipating member 1 from one side in the third direction. The coolant W flows between the water jacket and the base portion 2.

[0021] Here, when multiple heating elements are arranged side by side in the direction in which the refrigerant W flows, such as heating elements 4A, 4B, and 4C, the following problem occurs. When the heating element arranged on the upstream side is cooled by the refrigerant W, the temperature of the refrigerant W rises due to heat transfer. Therefore, the temperature of the refrigerant W increases toward the downstream side, and the cooling performance on the downstream side decreases.

[0022] Therefore, in the present embodiment, the relationship of the diameters DA, DB, and DC of the pin fins 30A that make up the upstream fin group 3A, the diameters DB of the pin fins 30B that make up the central fin group 3B, and the diameters DC of the pin fins 30C that make up the downstream fin group 3C is DA < DB < DC. That is, the diameter of the pin fins becomes thicker for the downstream fin groups. Note that the diameter DA of each of the pin fins 30A arranged in the region RA is the same, the diameter DB of each of the pin fins 30B arranged in the region RB is the same, and the diameter DC of each of the pin fins 30C arranged in the region RC is the same. Also, the individual third-direction lengths in the respective regions RA, RB, and RC of the pin fins 30A, 30B, and 30C are the same, and the third-direction lengths of the pin fins 30A, 30B, and 30C are the same.

[0023] As a result, on the downstream side where the temperature of the refrigerant W increases and improvement of the cooling performance is required, by increasing the diameters DB and DC of the pin fins 30B and 30C, the Reynolds number of the refrigerant W flowing around the pin fins increases, and the heat transfer coefficient increases. Therefore, the cooling performance can be improved on the downstream side. On the other hand, on the upstream side where the cooling performance is sufficient, by reducing the diameter DA of the pin fins 30A, the pressure loss is reduced. Thereby, the increase in the pressure loss at the location where the diameter is increased can be reduced, and the overall pressure loss can be suppressed.

[0024] That is, it is possible to suppress the overall pressure loss while improving the overall cooling performance. By improving the cooling performance, the temperature difference between the heat generating bodies 4A, 4B, and 4C can be suppressed, and the temperature of the downstream heat generating body 4C, which is likely to have a high temperature, can be lowered.

[0025] In other words, with the above-described configuration, it is as follows. The cross-sectional area in a cross-section extending perpendicular to the third direction is the cross-sectional area of the pin fins 30A, 30B, and 30C. Since the pin fins 30A, 30B, and 30C are cylindrical, the cross-sectional area is constant at any position in the third direction. Since the relationship of the diameters is DA < DB < DC, the cross-sectional area of the pin fin 30B is larger than the cross-sectional area of the pin fin 30A, and the cross-sectional area of the pin fin 30C is larger than the cross-sectional area of the pin fin 30B. That is, at the same position in the third direction, the cross-sectional areas of the pin fins 30B and 30C arranged in at least one of the regions RB and RC are larger than the cross-sectional area of the pin fin 30A arranged in another region RA.

[0026] By increasing the cross-sectional areas of the pin fins 30B and 30C, the Reynolds number of the flow of the refrigerant W increases, and the heat transfer coefficient increases. At locations where the need for cooling performance is high, the cross-sectional areas of the pin fins 30B and 30C are increased to improve the cooling performance, and at locations where the need for cooling performance is low, the cross-sectional area of the pin fin 30A is decreased to reduce the pressure loss. Therefore, the overall cooling performance can be improved while suppressing the overall pressure loss. As a result, the pressure loss can be suppressed while suppressing the temperature difference between the heat generating bodies 4A, 4B, and 4C.

[0027] Further, the heat radiating member 1 has pin fins 30A, 30B, and 30C whose cross-sectional areas increase as it goes toward one side in the first direction, which is the downstream side where the refrigerant W flows. When the variation in the heat generation amounts of the heat generating bodies 4A, 4B, and 4C arranged for each of the fin groups 3A, 3B, and 3C is small, the cooling performance can be improved on the downstream side where the temperature of the heat generating body tends to be high, and the variation in the temperature of the heat generating body can be suppressed.

[0028] Additionally, multiple fin groups 3A, 3B, 3C are arranged in the first direction. The cross-sectional areas of the individual pin fins 30A, 30B, 30C in the same fin group are the same, and the cross-sectional areas of the individual pin fins 30A, 30B, 30C in each fin group 3A, 3B, 3C are different. By making the cross-sectional areas of the pin fins 30A, 30B, 30C different depending on the heat generation amount of the heat generating elements 4A, 4B, 4C arranged in each fin group 3A, 3B, 3C, it is possible to suppress the variation in temperature of the heat generating elements 4A, 4B, 4C.

[0029] Furthermore, the cross-sectional area of ​​each pin fin 30A, 30B, 30C is larger in the fin group on one side in the first direction, which is the downstream side of the flow of the refrigerant W. When the variation in the amount of heat generated by the heating elements 4A, 4B, 4C arranged in each fin group 3A, 3B, 3C is small, the cooling performance can be improved on the downstream side where the temperature of the heating elements tends to be high, and the variation in temperature of the heating elements can be suppressed.

[0030] It is not necessarily the case that the cross-sectional area of ​​each pin fin 30A, 30B, 30C is larger in the fin group on one side of the first direction. For example, if a heat generating element that generates a large amount of heat is located on the upstream side, the cross-sectional area of ​​each pin fin 30A, 30B, 30C is made larger in the fin group on the other side of the first direction, that is, the upstream side. The relationship between the cross-sectional areas is adjusted according to the heat generating element.

[0031] Also, in the same fin group, the cross-sectional area of ​​some of the pin fins may be made larger.

[0032] <2. Various embodiments of pin fins> As described above, the pin fins 30A, 30B, 30C are cylindrical, and the diameters DB, DC of the pin fins 30B, 30C arranged in at least one of the regions RB, RC are larger than the diameter DA of the pin fin 30A arranged in another region RA. This makes it possible to increase the Reynolds number and the heat transfer coefficient by increasing the pin fin diameter in areas where improved cooling performance is highly required.

[0033] However, the shape of the pin fins is not limited to a cylindrical shape. For example, as shown in FIG. 2, the pin fins 301A, 301B, and 301C arranged in the regions RA, RB, and RC may be elliptical columnar. In this case, as shown in FIG. 2, the pin fins 301A, 301B, and 301C are arranged such that the major diameters DA1, DB1, and DC1 of the pin fins 301A, 301B, and 301C are along the second direction, and the magnitude relationship of the major diameters is DA1 < DB1 < DC1. That is, the major diameter of the pin fins is increased toward the downstream side, increasing the Reynolds number and the heat transfer coefficient, and improving the cooling performance.

[0034] In addition, when the pin fins 301A, 301B, and 301C are arranged such that the minor diameters of the pin fins 301A, 301B, and 301C are along the second direction, the minor diameter may be made longer toward the downstream.

[0035] That is, the pin fins 301A, 301B, and 301C are elliptical columnar, and the major diameter or minor diameter of the pin fins 301B and 301C arranged in at least one of the regions RB and RC is longer than the major diameter or minor diameter of the pin fin 301A arranged in another region RA. Thereby, in a location where there is a high need to improve the cooling performance, by increasing the major diameter or minor diameter of the pin fins, the Reynolds number and the heat transfer coefficient can be increased.

[0036] Further, as shown in FIG. 3, the pin fin may be a square columnar 302. Note that the pin fin may be a triangular column or a polygon having five or more sides (for example, a hexagonal column, etc.). That is, the pin fin is prism-shaped. Thereby, the heat transfer coefficient can be adjusted by adjusting the cross-sectional area of the prism.

[0037] Further, as shown in FIG. 4, the pin fin may be a frustum-shaped pin fin 303. Although FIG. 4 shows a frustum-shaped pin fin, the pin fin may also be a frustum-shaped pyramid, etc. For example, when the pin fin is frustum-shaped, the cross-sectional area of the circular cross-section located at the same third direction position is adjusted.

[0038] 5, the pin fins may be semi-cylindrical pin fins 304. The pin fins 304 have a flat surface portion 304A and a curved surface portion 304B. The flat surface portion 304A is joined to the base portion 2. The curved surface portion 304B faces the direction F in which the refrigerant W flows. Note that semi-cylindrical pin fins may be implemented that are shaped only on the other side (upstream side) in the first direction of the cylindrical pin fins extending in the third direction described above.

[0039] The pin fins of the various shapes described above may be combined. In this case, the relationship between the cross-sectional areas of the pin fins may be adjusted at different positions in the third direction. In other words, the relationship between the cross-sectional areas does not necessarily have to be adjusted at the same position in the third direction.

[0040] <3. Arrangement of pin fins in the fin group> In the fin groups 3A, 3B, and 3C shown in Fig. 1, the pin fins 30A, 30B, and 30C are arranged in a so-called staggered pattern. That is, in at least one of the fin groups 3A, 3B, and 3C, the pin fins 30A, 30B, and 30C arranged in the second direction are set as fin rows, and between the pin fins in one fin row that are adjacent to each other in the first direction, the pin fins in the other fin row are arranged. This enhances the turbulence effect in the fin group, and improves the cooling performance.

[0041] 6, in at least one of the fin groups 3A, 3B, 3C, pin fins 30A, 30B, 30C arranged in the second direction may be configured as a fin row, and the second direction positions of the pin fins in adjacent fin rows in the first direction may be the same. This can reduce pressure loss more than when the pin fins are arranged in a staggered pattern.

[0042] Note that the second direction positions of the pin fins being aligned does not necessarily mean that the center positions of the pin fins are exactly aligned, but also means that the centers of the pin fins are slightly misaligned, and the same applies below.

[0043] In addition, the above pin fin arrangements may be combined in multiple fin groups.

[0044] <4. Method for forming heat dissipation member> The heat dissipation member 1 is formed, for example, by integrally forming the pin fins 30A, 30B, 30C and the base portion 2 by forging. In this case, as shown in Fig. 7, the pin fins 30A, 30B, 30C and the base portion 2 are configured as an integral member. As a result, the joints between the pin fins 30A, 30B, 30C and the base portion 2 are made of the same material as the pin fins 30A, 30B, 30C and the base portion 2, so that the thermal conductivity at the joints can be made higher than that of brazing, which will be described later.

[0045] Also, the heat dissipation member 1 may be formed, for example, by brazing the pin fins 30A, 30B, and 30C to the base portion 2. In this case, as shown in FIG. 8, the pin fins 30A, 30B, and 30C and the base portion 2 are joined by a brazing material 5. That is, the pin fins 30A, 30B, and 30C and the base portion 2 are configured as separate members. This makes it easy to change the specifications of some of the pin fins. For example, this is effective in the case where some of the pin fins and the base portion are formed by forging, and the remaining pin fins are fixed to the base portion by brazing.

[0046] <5. Fin group configuration> In the configuration shown in FIG. 1, the configuration between the fin groups 3A and 3B is as follows. The heat dissipation member 1 has a first fin group 3B on one side in the first direction of the fin groups 3A and 3B adjacent to each other in the first direction, and a second fin group 3A on the other side in the first direction. The second direction positions of the pin fins are the same for the row PB of the pin fins 30B arranged in the second direction on the furthest side in the first direction in the first fin group 3B, and the row PA of the pin fins 30A arranged in the second direction on the furthest side in the first direction in the second fin group 3A. This can reduce pressure loss in the row PB of the pin fins arranged in the first fin group 3B on the furthest side in the other direction in the first direction. The same configuration is also used between the fin groups 3B and 3C shown in FIG. 1.

[0047] 9, the fin rows PA, PB may be arranged in a so-called staggered pattern between the fin groups 3A, 3B. That is, the heat dissipation member 1 has a third fin group 3B on one side in the first direction in the fin groups 3A, 3B adjacent to each other in the first direction, and a fourth fin group 3A on the other side in the first direction. In the row PB of pin fins arranged in the second direction on the furthest side in the first direction in the third fin group 3B, and the row PA of pin fins arranged in the second direction on the furthest side in the first direction in the fourth fin group 3A, the pin fins in one row of pin fins are arranged between the pin fins in the other row of pin fins that are adjacent to each other in the second direction. This makes it easier to generate turbulence in the row PB of pin fins on the furthest side in the other first direction in the third fin group 3B, thereby improving the cooling performance.

[0048] <5. Second embodiment> Fig. 10 is a plan view showing a configuration of a heat dissipation member 1 according to a second embodiment of the present disclosure. In Fig. 10, a plurality of heat generating elements (not shown) are arranged along the flow direction of the refrigerant W, similarly to Fig. 1.

[0049] The individual cylindrical pin fins 30A arranged in region RA and constituting the upstream fin group 3A have the same diameter in region RA. Similarly, the individual cylindrical pin fins 30B arranged in region RB and constituting the central fin group 3B have the same diameter in region RB, and the individual cylindrical pin fins 30C arranged in region RC and constituting the downstream fin group 3C have the same diameter in region RC. The pin fins 30A, 30B, 30C also have the same diameter.

[0050] The lengths of the sides of the regions RA, RB, and RC in the first direction are the same. The lengths of the sides of the regions RA, RB, and RC in the second direction are the same. In other words, the areas of the regions RA, RB, and RC are the same.

[0051] In the regions RA, RB, and RC, the number of pin fins 30A, 30B, and 30C arranged in the first direction in the rows arranged in the second direction is the same. In the example of FIG.

[0052] 10, the number of pin fins 30A, 30B, 30C aligned in the second direction is 4 or 5 in region RA, 6 in region RB, and 7 or 8 in region RC. That is, the number of pin fins 30A, 30B, 30C aligned in the second direction is greater in the downstream region.

[0053] As a result, the number of pin fins 30A, 30B, 30C in each region RA, RB, RC increases in the more downstream region. Here, the cross-sectional area of ​​the pin fin is defined as the cross-sectional area of ​​a section that spreads perpendicularly to the third direction and is located at the same third direction position. The sum of the cross-sectional areas of the pin fins 30A, 30B, 30C in each region RA, RB, RC is divided by the area of ​​each region RA, RB, RC to calculate the arrangement density, which is the cross-sectional area of ​​the pin fins per unit area of ​​the base portion 2, for each region RA, RB, RC. The magnitude relationship of the arrangement density of each region RA, RB, RC is the arrangement density of region RA < the arrangement density of region RB < the arrangement density of region RC.

[0054] In this way, the pin fins are arranged at a higher density in the downstream region. As a result, the spacing between the pin fins is narrowed toward the downstream side where improved cooling performance is required, and the flow rate of the refrigerant W flowing between the pin fins is increased, thereby improving cooling performance. In the example of FIG. 10, the spacing t1 between the pin fins in the second direction is narrowed. On the other hand, on the upstream side where cooling performance is sufficient, the spacing between the pin fins is widened, reducing pressure loss. Therefore, the overall cooling performance can be improved while suppressing the overall pressure loss.

[0055] In other words, in this embodiment, the arrangement density of the pin fins 30B, 30C arranged in at least one of the regions RB, RC is higher than the arrangement density of the pin fins 30A arranged in another region RA, where the cross-sectional area of ​​the pin fins per unit area of ​​the base portion 2 is the arrangement density. By increasing the arrangement density of the pin fins, the interval between adjacent pin fins becomes narrower, the flow rate of the coolant W increases, and the cooling performance improves. By increasing the arrangement density of the pin fins 30B, 30C in places where the cooling performance is highly required, the cooling performance is improved, and by decreasing the arrangement density of the pin fins 30A in places where the cooling performance is less required, the pressure loss can be reduced. Therefore, the pressure loss can be reduced while suppressing the temperature difference between the heat generating bodies.

[0056] Furthermore, the number of pin fins 30A, 30B, 30C per unit area of ​​the base portion 2 is greater in at least one of the regions RB, RC than in another region RA. If the cross-sectional area of ​​each pin fin is the same in at least one of the regions RB, RC and the other region RA, the arrangement density can be adjusted by the number of pin fins per unit area.

[0057] Furthermore, the number of pin fins 30A, 30B, 30C aligned in the second direction per unit length in the second direction is greater in at least one region RB, RC than in another region RA. This allows the flow speed of the refrigerant W flowing between the pin fins to be adjusted by adjusting the interval t1 between adjacent pin fins in the second direction, thereby adjusting the cooling performance.

[0058] Moreover, the heat dissipation member 1 has pin fins 30A, 30B, 30C arranged at a higher density toward one side in the first direction, which is the downstream side along which the refrigerant W flows. When the temperature of the refrigerant W increases toward the downstream side and improved cooling performance is required toward the downstream side, by increasing the arrangement density of the pin fins, it is possible to suppress temperature variation in the heating elements arranged along the flow direction. Furthermore, by decreasing the arrangement density of the pin fins on the upstream side, where improved cooling performance is less required, pressure loss can be reduced.

[0059] In addition, the arrangement density of the pin fins in each of the multiple fin groups 3A, 3B, 3C arranged in the first direction is different. By varying the arrangement density of the pin fins in each of the fin groups 3A, 3B, 3C according to the heat generation amount of the heat generating element, it is possible to suppress the variation in temperature of the heat generating element.

[0060] Furthermore, the pin fins are arranged more densely in the fin groups 3A, 3B, 3C on one side in the first direction, which is the downstream side of the flow of the refrigerant W. When the variation in the amount of heat generated by the heat generating elements arranged in each of the fin groups 3A, 3B, 3C is small, the cooling performance can be improved on the downstream side where the temperature of the heat generating elements tends to be high, and the variation in temperature of the heat generating elements can be suppressed.

[0061] It is not necessarily the case that the density of the pin fins is higher in the fin groups on one side of the first direction. For example, if a heat generating element that generates a large amount of heat is located on the upstream side, the density of the pin fins is increased in the fin groups on the other upstream side of the first direction, and the density relationship is adjusted according to the heat generating element.

[0062] Furthermore, in the same group of fins, the arrangement density may be increased in some areas.

[0063] Fig. 11 is a plan view showing a heat dissipation member 1 according to a modified example of the second embodiment. The configuration shown in Fig. 11 differs from the configuration shown in Fig. 10 in that the number of pin fins 30A, 30B, 30C aligned in the second direction is the same in the regions RA, RB, RC, that is, four or five. Meanwhile, the number of pin fins 30A, 30B, 30C aligned in the second direction aligned in the first direction in the row is six in the region RA, seven in the region RB, and eight in the region RC, and the number of pin fins is greater in the downstream region. This increases the arrangement density of the pin fins in the downstream region.

[0064] In other words, the number of pin fins 30A, 30B, 30C arranged in the second direction per unit length in the first direction is such that at least one of the regions RB, RC has more than the other region RA. Thereby, by adjusting the interval t2 between adjacent pin fins in the diagonal direction inclined from the first direction and the second direction, the flow velocity of the refrigerant W flowing between the pin fins can be adjusted, and the cooling performance can be adjusted.

[0065] Note that the adjustment of the arrangement density of the pin fins shown as examples in FIGS. 10 and 11 may be implemented in combination.

[0066] Also, regarding the various embodiments of the pin fins described above, the arrangement form of the pin fins in the fin group, the method of forming the heat radiating member, and the configuration between the fin groups, it is possible to implement them by applying them to the second embodiment.

[0067] Note that, as shown in the first embodiment (FIG. 1, etc.), it is also possible to adjust the arrangement density of the pin fins by adjusting the cross-sectional area of each individual pin fin. For example, in the example of FIG. 1, the number of pin fins 30A, 30B, 30C is the same in the regions RA, RB, RC, but by setting the diameters of the pin fins 30A, 30B, 30C as DA < DB < DC, the arrangement density becomes higher in the downstream region.

[0068] <6. Third Embodiment> FIG. 12 is a diagram showing the configuration of the heat radiating member 1 according to the third embodiment of the present disclosure. The upper part of FIG. 12 shows a plan view seen from one side in the third direction, and the lower part of FIG. 12 is a side view seen from one side in the second direction. In the lower part of FIG. 12, the side cross-section of the water jacket 6 is also shown. Also, in FIG. 12, a plurality of heat generating bodies (not shown in the same way as FIG. 1) are arranged along the flow direction of the refrigerant W.

[0069] The individual cylindrical pin fins 30A arranged in region RA and constituting the upstream fin group 3A have the same diameter in region RA. Similarly, the individual cylindrical pin fins 30B arranged in region RB and constituting the central fin group 3B have the same diameter in region RB, and the individual cylindrical pin fins 30C arranged in region RC and constituting the downstream fin group 3C have the same diameter in region RC. The pin fins 30A, 30B, 30C also have the same diameter.

[0070] As shown in the lower part of FIG. 12, the relationship in magnitude between the lengths ha, hb, and hc of the pin fins 30A, 30B, and 30C in the third direction arranged in each of the regions RA, RB, and RC is as follows: ha <hb<hcとしている。

[0071] Further, a lower surface (the other side surface in the third direction) 61A of a top surface portion 61 of the water jacket 6, which functions as a cover portion that covers the heat dissipation member 1 from one side in the third direction, faces the top surfaces (one side surface in the third direction) of the pin fins 30A, 30B, 30C in the third direction. Gaps ta, tb, tc are provided between the lower surface 61A and the top surfaces of the pin fins 30A, 30B, 30C, respectively. Note that no gap may be provided between the top surface of the pin fin 30C, which has the longest length in the third direction, and the lower surface 61A.

[0072] 12, the surface area of ​​pin fins 30A, 30B, 30C that can come into contact with refrigerant W is the sum of the area of ​​the circumferential surface and the area of ​​the top surface. Therefore, the surface area of ​​pin fin 30A < the surface area of ​​pin fin 30B < the surface area of ​​pin fin 30C, and the surface area of ​​the pin fins is larger the further downstream the region. As a result, the area for heat transfer is larger the further downstream the cooling performance needs to be improved, thereby improving cooling performance.

[0073] On the other hand, on the upstream side where the cooling performance is sufficient, the length of the pin fins in the third direction can be shortened to increase the space between the lower surface 61A of the water jacket 6 and the top surfaces of the pin fins, thereby reducing pressure loss. Therefore, the overall cooling performance can be improved while suppressing the overall pressure loss.

[0074] In other words, the surface area of ​​the pin fins that can contact the refrigerant W is defined as the surface area of ​​the pin fins, and the surface area of ​​the pin fins 30B, 30C arranged in at least one of the regions RB, RC is greater than the surface area of ​​the pin fin 30A arranged in the other region RA. Increasing the surface area of ​​the pin fins that can contact the refrigerant W improves cooling performance. In areas where cooling performance is highly required, the surface area of ​​the pin fins is increased to improve cooling performance, and in areas where cooling performance is less required, the surface area of ​​the pin fins is decreased to reduce pressure loss. Therefore, pressure loss can be reduced while suppressing the temperature difference between heating elements.

[0075] Moreover, the heat dissipation member 1 has pin fins 30A, 30B, 30C whose surface area increases toward one side in the first direction, which is the downstream side of the flow of the refrigerant W. In the case where the temperature of the refrigerant W increases toward the downstream side and improved cooling performance is required toward the downstream side, the surface area of ​​the pin fins can be increased to suppress temperature variation of the heating elements arranged along the flow direction. Furthermore, in the upstream side where improved cooling performance is less required, the surface area of ​​the pin fins can be reduced to reduce pressure loss.

[0076] Fin groups 3A, 3B, 3C are arranged in the first direction, and the surface area of ​​each pin fin 30A, 30B, 30C in the same fin group is the same, but the surface area of ​​each pin fin is different for each fin group. By making the surface area of ​​the pin fins different depending on the heat generation amount of the heat generation element arranged for each fin group, it is possible to suppress variation in temperature of the heat generation element.

[0077] Furthermore, the surface area of ​​each pin fin is larger in the fin groups 3A, 3B, 3C located on one side in the first direction, which is the downstream side of the flow of the refrigerant W. When there is little variation in the amount of heat generated by the heat generating elements arranged in each fin group, it is possible to improve the cooling performance on the downstream side where the temperature of the heat generating elements tends to be high, and to suppress variation in the temperature of the heat generating elements.

[0078] Furthermore, the third direction lengths hb, hc of the pin fins 30B, 30C arranged in at least one of the regions RB, RC are longer than the third direction length ha of the pin fin 30A arranged in the other region RA. The surface area of ​​the pin fins can be adjusted by adjusting the third direction lengths of the pin fins 30A, 30B, 30C. Furthermore, the shorter the third direction length of the pin fin is, the longer the gap between the top surface of the pin fin and the top surface portion 61 of the water jacket 6 becomes, thereby reducing pressure loss.

[0079] It is not necessarily the case that the surface area of ​​the pin fins is larger for fin groups on one side of the first direction. For example, if a heat generating element that generates a large amount of heat is located on the upstream side, the surface area of ​​the pin fins is made larger for fin groups on the other upstream side of the first direction, and the size relationship of the surface areas is adjusted according to the heat generating element.

[0080] Also, in the same fin group, the surface area of ​​the pin fins may be increased in some regions.

[0081] The surface area of ​​the pin fin may be adjusted by providing irregularities on the surface of the pin fin. FIG. 13 is a diagram showing an example of a pin fin with irregularities formed on its surface. In the example of the pin fin 30 shown in FIG. 13, grooves extending in the third direction are formed on the surface of the pin fin 30, thereby providing recesses 30R and protrusions 30T on the surface of the pin fin 30. The method of forming the irregularities is not limited to this, and various methods can be implemented, such as providing hemispherical irregularities on the surface of the pin fin. Also, only one of the recesses and protrusions may be formed on the surface of the pin fin.

[0082] 12, the surface area of ​​the pin fin may be made different in the regions RA, RB, and RC by forming irregularities on the surface of the pin fin. Note that, for example, in the upstream region RA, the surface area of ​​the pin fin may be made narrower by not forming irregularities on the surface of the pin fin.

[0083] In other words, the surface area of ​​the pin fin differs between at least one of the regions RB, RC and another region RA due to at least one of the concave portions formed on the surface of the pin fin by recessing radially inward and the convex portions formed on the surface of the pin fin by protruding radially outward. Note that the radial direction is the radial direction with respect to the central axis of the pin fin. As a result, in areas where there is a high need for improved cooling performance, the surface area of ​​the pin fin can be increased by the unevenness of the surface, thereby improving cooling performance, and in areas where there is a low need for improved cooling performance, the surface area of ​​the pin fin can be reduced by the unevenness of the surface, thereby reducing pressure loss.

[0084] Furthermore, the various pin fin embodiments, the arrangement of the pin fins in the fin group, the method of forming the heat dissipation member, and the configuration between the fin groups described above can be applied to the third embodiment.

[0085] <7.Other> The embodiments of the present disclosure have been described above. Note that the scope of the present disclosure is not limited to the above-described embodiments. The present disclosure can be implemented by adding various modifications to the above-described embodiments without departing from the spirit of the invention. In addition, the matters described in the above-described embodiments can be appropriately combined in any manner without causing any contradiction.

[0086] For example, a vapor chamber or a heat pipe may be provided between the heat generating element and the heat dissipating member. [Industrial Applicability]

[0087] The present disclosure can be utilized for cooling various heat generating bodies. [Explanation of symbols]

[0088] 1 Heat dissipation material 2 Base 3A Upstream fin group 3B Central fin group 3C Downstream fin group 4A, 4B, 4C Heating elements 5 Brazing material 6 Water Jacket 10 Heat dissipation fin section 21 3rd direction one side 22 3rd direction other side 30 Pinfin 30A, 30B, 30C Pinfin 30R recess 30T protrusion 61 Top section 61A Bottom 301A, 301B, 301C Pinfin 302,303,304 Pinfin RA,RB,RC area W Refrigerant

Claims

1. a plate-shaped base portion that extends in a first direction along a direction in which the refrigerant flows and in a second direction perpendicular to the first direction, and has a thickness in a third direction perpendicular to the first direction and the second direction; At least one fin group including a plurality of pin fins protruding in a columnar shape from the base portion to one side in a third direction; having A plurality of fin rows, each having a plurality of pin fins arranged in a second direction, are arranged in a first direction; The pin fin has an elliptical cylindrical shape with a major axis along the second direction, The surface area that the refrigerant can contact is defined as the surface area of ​​the pin fins, A heat dissipation member in which the long diameter of the pin fins arranged in at least one region is longer than the long diameter of the pin fins arranged in another region, such that the surface area of ​​the pin fins arranged in the at least one region is larger than the surface area of ​​the pin fins arranged in the other region.

2. The heat dissipation member according to claim 1 , wherein the pin fins have a surface area that increases toward one side in a first direction, which is a downstream side in which the coolant flows.

3. The fin group is arranged in a first direction, The surface area of ​​each of the pin fins in the same fin group is the same; The heat dissipation member according to claim 1 or 2, wherein a surface area of ​​each of the pin fins in each of the fin groups is different.

4. The heat dissipation member according to claim 3 , wherein the surface area of ​​each of the pin fins is larger in the fin groups closer to one side in a first direction, which is a downstream side in which the coolant flows.

5. The heat dissipation member according to claim 1 , wherein a third direction length of the pin fins arranged in the at least one region is longer than a third direction length of the pin fins arranged in the other region.

6. A heat dissipation member as described in any one of claims 1 to 4, wherein the surface area of ​​the pin fin differs between the at least one region and the other region due to at least one of a recess formed radially inward on the surface of the pin fin and a protrusion formed radially outward on the surface of the pin fin.

7. A heat dissipation member as described in any one of claims 1 to 6, wherein in at least one of the at least one fin groups, the pin fins arranged in the second direction are arranged as a fin row, and between the fin rows adjacent to each other in the first direction, the pin fins in one of the fin rows are arranged between the pin fins in the other fin row that are adjacent to each other in the second direction.

8. A heat dissipation member described in any one of claims 1 to 7, wherein in at least one of the at least one fin groups, the pin fins arranged in the second direction are considered to be a fin row, and the second direction positions of the pin fins are the same between adjacent fin rows in the first direction.

9. The heat dissipation member according to claim 1 , wherein at least any one of the pin fins and the base portion are configured as an integral member.

10. The heat dissipation member according to claim 1 , wherein at least any of the pin fins and the base portion are configured as separate members.

11. The fin groups adjacent to each other in the first direction include a first fin group on one side in the first direction and a second fin group on the other side in the first direction, A heat dissipation member described in any one of claims 1 to 10, wherein the second direction positions of the pin fins in the row of pin fins in the first fin group lined up in the second direction on the other side of the first direction and the row of pin fins in the second fin group lined up in the second direction on the one side of the first direction are the same.

12. a third fin group on one side in the first direction and a fourth fin group on the other side in the first direction, among the fin groups adjacent to each other in the first direction, A heat dissipation member as described in any one of claims 1 to 10, wherein a row of pin fins in the third fin group that is aligned in the second direction on the other side of the first direction, and a row of pin fins in the fourth fin group that is aligned in the second direction on the other side of the first direction, are arranged between the pin fins in one row of pin fins that are adjacent to each other in the second direction.

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