Heat sink material

Abstract

To provide a heat sink member with excellent heat dissipation by using a graphite-copper composite material in which scaly graphite particles are laminated.SOLUTION: A heat sink member 10 includes a first heat sink 11 on which a heat source is placed on an upper surface, and a second heat sink 12 extending downward from a lower surface of the first heat sink 11, and the first heat sink 11 and the second heat sink 12 contain scaly graphite particles laminated via a copper layer, are made of a graphite-copper composite material having a thermal conductivity in a direction perpendicular to a stacking direction of the scaly graphite particles that is greater than the thermal conductivity in the stacking direction, and is arranged such that the lamination direction of the scaly graphite particles is horizontal.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a heat sink member used in a heat sink for cooling a heat source such as a semiconductor element, for example an IGBT. [Background technology]

[0002] Conventionally, heat sinks are used to cool heat sources such as semiconductor elements such as IGBTs. Heat sinks use a heat sink plate (heat dissipation substrate) as a component for dissipating heat generated from the heat source.

[0003] For example, Patent Document 1 describes an invention related to a heat dissipation substrate made of a Cu-C composite (graphite-copper composite material), in which thin-film Cu layers are formed on the front and back sides of the Cu-C composite material to deal with stress generated by temperature increases.

[0004] Furthermore, Patent Documents 2 and 3 describe inventions relating to a heat sink made of a graphite-copper composite material in which flake graphite particles are stacked, and mention the difference in thermal conductivity depending on the stacking direction of the flake graphite particles. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-142569 A [Patent Document 2] JP 2019-192890 A [Patent Document 3] JP 2020-113758 A Summary of the Invention [Problem to be solved by the invention]

[0006] With the recent advances in new technologies such as IOT, AI, and electric vehicles, there is a demand for even higher thermal conductivity in heat sinks used as heat dissipation components for heat sinks. Heat sinks made of graphite-copper composite materials with laminations of flake graphite exhibit high thermal conductivity, but when used as heat sink components, attention must be paid to the lamination direction of the flake graphite particles.

[0007] The present invention is intended to solve the above-mentioned problems of the conventional art, and provides a heat sink member with excellent heat dissipation properties by using a graphite-copper composite material in which flake graphite particles are laminated. [Means for solving the problem]

[0008] In order to solve the above problems, the heat sink member of the present invention is a heat sink member consisting of a first heat dissipation plate on whose upper surface a heat source is placed, and a second heat dissipation plate extending downward from the lower surface of the first heat dissipation plate, wherein the first heat dissipation plate and the second heat dissipation plate are made of a graphite-copper composite material containing flake graphite particles stacked via a copper layer, the thermal conductivity of which in a direction perpendicular to the stacking direction of the flake graphite particles is greater than the thermal conductivity in the stacking direction, and the stacking direction of the flake graphite particles is arranged so that it is horizontal.

[0009] Also preferably, the first heat dissipation plate and the plurality of second heat dissipation plates are integrally formed.

[0010] Also preferably, the first heat dissipation plate and the plurality of second heat dissipation plates are joined together.

[0011] It is also preferable that the first heat dissipation plate is arranged so that the stacking direction of the flake graphite particles in the central portion where the heat source is placed is perpendicular to the stacking direction of the flake graphite particles on both sides of the central portion.

[0012] Also preferably, the heat exchanger includes a turbulence generating portion for generating a turbulent flow between the plurality of second heat dissipation plates.

[0013] Also preferably, the second heat sink is extended upward so as to surround both ends of the first heat sink.

[0014] Also preferably, a step is provided on the periphery of the upper surface of the first heat sink.

[0015] Also preferably, the heat sink device has a holding portion for holding the distance between the second heat sinks. Effect of the Invention

[0016] The heat sink member of the present invention is a heat sink member consisting of a first heat sink plate on which a heat source is placed on the upper surface, and a second heat sink plate extending downward from the lower surface of the first heat sink plate. The first heat sink plate and the second heat sink plate are graphite-copper composite materials containing scaly graphite particles stacked via a copper layer, and having a higher thermal conductivity in a direction perpendicular to the stacking direction of the scaly graphite particles than in the stacking direction. The flake graphite particles are arranged so that the stacking direction is horizontal. Therefore, the arrangement is such that the thermal conductivity in the vertical direction is high, and heat generated from the heat source placed on the upper surface can be effectively dissipated in the vertical direction.

[0017] Furthermore, when the first heat sink plate and multiple second heat sink plates are integrally molded, there is no need to join the heat sink plates together, and heat can be dissipated smoothly at the boundary between the first heat sink plate and the second heat sink plate.

[0018] In addition, when a first heat sink plate and multiple second heat sink plates are joined together, by making the first heat sink plate and the second heat sink plate separate bodies, it is possible to combine the directionality of the magnitude of thermal conduction in various ways.

[0019] Furthermore, when the first heat dissipation plate is arranged so that the stacking direction of the flake graphite particles in the central portion where the heat source is placed is perpendicular to the stacking direction of the flake graphite particles on both sides of the central portion, the directionality of the magnitude of thermal conduction can be changed between the central portion and both sides, thereby varying the vertical heat dissipation and horizontal heat dissipation as necessary.

[0020] Furthermore, if a turbulence generating section that generates turbulence between multiple second heat sinks is provided, turbulence can be generated in the fluid (air, water) between the second heat sinks, thereby effectively cooling the second heat sinks.

[0021] Furthermore, when the second heat sink is extended upward so as to surround both ends of the first heat sink, the heat generated by the heat source can be dissipated without being dissipated to the surroundings.

[0022] In addition, if a step is provided on the peripheral edge of the upper surface of the first heat sink, a gap can be created between the mounting plate and the first heat sink using the step, thereby preventing warping of the first heat sink due to thermal expansion.

[0023] Furthermore, if a holding portion is provided to maintain the spacing between multiple second heat sinks, it is possible to prevent the joint between the second heat sink and the first heat sink from peeling off due to force being applied to the second heat sink.

[0024] Thus, according to the present invention, a heat sink member having excellent heat dissipation properties can be provided by using a graphite-copper composite material in which flake graphite particles are laminated. [Brief description of the drawings]

[0025] [Figure 1] FIG. 2 is a perspective view showing a graphite-copper composite material used in a heat sink member according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view showing a heat sink member and a mounting plate according to the first embodiment. [Diagram 3] FIG. 2 is a perspective view showing an attached state of the heat sink member according to the first embodiment. [Figure 4] FIG. 11 is a perspective view showing a heat sink member according to a second embodiment. [Diagram 5] FIG. 11 is a perspective view showing a heat sink member according to the third and fourth embodiments. [Figure 6] FIG. 11 is a perspective view showing a heat sink member according to the fifth and sixth embodiments. [Figure 7] FIG. 13 is a perspective view showing a heat sink member according to the seventh and eighth embodiments. [Figure 8] FIG. 13 is a perspective view showing a heat sink member according to a ninth embodiment. [Figure 9] FIG. 23 is a perspective view showing a heat sink member according to a tenth embodiment. [Figure 10] FIG. 15 is a cross-sectional view showing the heat sink members according to the eleventh and twelfth embodiments. [Figure 11] 13A and 13B are a front view and a side view, respectively, showing a heat sink member according to a thirteenth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Next, a heat sink member according to an embodiment of the present invention will be described. The heat sink member according to this embodiment has a heat source placed on the upper surface thereof via an insulating layer. The heat source may be a semiconductor element such as an IGBT. The material is a graphite-copper composite material.

[0027] (Graphite-copper composite material) The graphite-copper composite material used in this embodiment will be described with reference to Fig. 1. Fig. 1(A) is a perspective view showing a graphite-copper composite material 9. The graphite-copper composite material 9 contains flake graphite particles stacked with copper layers interposed between them. In Fig. 1(A), the ellipses denoted by reference numeral 1 are schematic representations of flake graphite particles, and the straight lines denoted by reference numeral 2 are schematic representations of layers of stacked flake graphite particles. In the following figures, only the ellipses and straight lines are shown, and the reference numerals are omitted.

[0028] 1(A), the flake graphite particles 1 are stacked from bottom to top, and the white arrow Z indicates the stacking direction of the flake graphite particles. The black arrows X and Y are perpendicular to the white arrow Z and are perpendicular to the stacking direction of the flake graphite particles.

[0029] Comparing the thermal conductivity of the graphite-copper composite material 9 in each direction, the thermal conductivity in the directions of the black arrows X and Y is greater than the thermal conductivity in the direction of the white arrow Z. In other words, the thermal conductivity in the direction (X, Y) perpendicular to the stacking direction of the flake graphite particles 2 is greater than the thermal conductivity in the stacking direction (Z). This is because, while heat is easily conducted between adjacent flake graphite particles 2 in the direction (X, Y) where the flake graphite particles 2 with high thermal conductivity are adjacent to each other, there is a copper layer between the upper and lower flake graphite particles 2, which has a lower thermal conductivity than graphite.

[0030] 1(B) shows a state in which the graphite-copper composite material 9 has been cut. In this manner, the graphite-copper composite material 9 can be cut to a desired length and thickness to form a plate-like material.

[0031] The graphite-copper composite material 9 is a sintered body obtained using flake graphite particles and copper particles as raw materials, and can be produced by pretreating the graphite particles to obtain the desired flake graphite particles, mixing them with predetermined copper particles to form a molding raw material, molding this, and sintering it under predetermined conditions.

[0032] The pretreatment of graphite particles is called lamination, and is carried out by applying shear force to the graphite particles to reduce their thickness. For example, JP 2019-94248 A discloses a method for producing thin-layer graphite.

[0033] Flake graphite particles and copper particles are mixed in a specified ratio and wet-mixed with an organic solvent to obtain a molding material. The molding material is then filled into a specified mold and sintered by multi-axis electric current sintering. The multi-axis electric current sintering method uses a multi-axis electric current sintering device that has a vertical pressure axis and two horizontal electric current axes, and sintering is performed with a uniform temperature distribution, making it possible to produce composite materials of stable quality.

[0034] Next, a heat sink member using a graphite-copper composite material 9 will be described. Several embodiments with different stacking directions (Z) of the flake graphite particles will be described below, but in all of the embodiments, the stacking direction (Z) of the flake graphite particles is horizontal, not vertical. This is because a configuration that reduces thermal conduction in the vertical direction is not suitable for dissipating heat generated by a heat source placed on the upper surface. The white arrows in each drawing indicate the stacking direction (Z) of the flake graphite particles (hereinafter simply referred to as the "stacking direction").

[0035] (Embodiment 1) 2 is a perspective view showing the heat sink member 10 and the mounting plate 3 according to the first embodiment. The mounting plate 3 is a plate material for mounting the heat sink member 10, and may be made of, for example, a copper plate. A hole H is formed in the center of the mounting plate 3 for inserting the heat sink member 30. A flange 4 is formed around the periphery of the hole H by press forming or the like. In addition, holes 5 are formed in the four corners of the mounting plate 3 for fixing the mounting plate 3 to a heat sink container (not shown) or the like.

[0036] The heat sink member 10 is composed of a first heat dissipation plate 11 and a second heat dissipation plate 12. The first heat dissipation plate 11 has an upper surface on which a heat source is placed. The second heat dissipation plate 12 extends downward from the lower surface of the first heat dissipation plate 11. In this embodiment, the number of second heat dissipation plates 12 is four, and they are arranged side by side in the left-right direction in FIG. 2. However, the number of second heat dissipation plates is not particularly limited.

[0037] The first heat sink 11 and the second heat sink 12 are integrally molded. The integral molding method may be such that the bottom surface of the graphite-copper composite material 9 manufactured in a rectangular parallelepiped shape is partially removed in a groove-like manner.

[0038] The stacking directions of the first heat sink 11 and the second heat sink 12 are both the front-to-back direction (depth direction) in Fig. 2. Therefore, the thermal conductivity in the up-down and left-right directions is greater than the thermal conductivity in the front-to-back direction (depth direction), and the heat generated by the heat source placed on the upper surface can be smoothly dissipated downward, while the four second heat sinks 12 can be effectively utilized while dissipating heat in the left-to-right direction.

[0039] 3 is a perspective view showing the mounting state of the heat sink member 10 according to the first embodiment. The first heat dissipation plate 11 of the heat sink member 10 is inserted through the hole H of the mounting plate 3, and the upper part of the first heat dissipation plate 11 is positioned so as to slightly protrude from the flange 4. At this time, the upper side surface of the first heat dissipation plate 11 and the inner side surface of the flange 4 are in contact with each other, and are fixed by brazing or soldering. In the case of a water-cooled heat sink, since there is a risk that cooling water will permeate the inside of the heat dissipation plate, it is preferable to previously plate the heat sink member 10 (with copper, nickel, etc.) to prevent the permeation of water. The mounting plate 3 and the method of mounting the heat sink member to the mounting plate 3 are the same in the following embodiments, so a description thereof will be omitted.

[0040] (Embodiment 2) 4 is a perspective view showing a heat sink member 20 according to a second embodiment. The heat sink member 20 is composed of a first heat dissipation plate 21 and a second heat dissipation plate 22. The first heat dissipation plate 21 has an upper surface on which a heat source is placed. The second heat dissipation plate 22 extends downward from the lower surface of the first heat dissipation plate 21. In this embodiment, the number of second heat dissipation plates 22 is four, and they are arranged side by side in the left-right direction in FIG. 2. However, the number of second heat dissipation plates is not particularly limited.

[0041] As shown in Fig. 4(A), the first heat sink 21 and the second heat sink 22 are joined at a joint 6. As shown in Fig. 4(B), a graphite-copper composite material 9 manufactured in a rectangular parallelepiped shape is cut to form the plates 21 and 22, and the upper surface of the second heat sink 22 is joined to the lower surface of the first heat sink 21. Examples of joining methods include brazing and diffusion bonding with copper powder sandwiched between the plates.

[0042] The stacking directions of the first heat sink 21 and the second heat sink 22 are both the front-to-back direction (depth direction) in Fig. 4. Therefore, the thermal conductivity in the up-down and left-right directions is greater than the thermal conductivity in the front-to-back direction (depth direction), and the heat generated by the heat source placed on the upper surface can be smoothly dissipated downward, while the four second heat sinks 22 can be effectively utilized while dissipating heat in the left-to-right direction.

[0043] (Embodiment 3) Fig. 5(A) is a perspective view showing a heat sink member 30 according to a third embodiment. The heat sink member 30 is composed of a first heat dissipation plate 31 and a second heat dissipation plate 32. The first heat dissipation plate 31 is for placing a heat source on its upper surface. The second heat dissipation plate 32 extends downward from the lower surface of the first heat dissipation plate 31. In this embodiment, the number of second heat dissipation plates 32 is four, and they are arranged side by side in the left-right direction in Fig. 5(A). However, the number of second heat dissipation plates is not particularly limited.

[0044] The first heat sink 31 and the second heat sink 32 are integrally molded. The integral molding method may be such that the bottom surface of the graphite-copper composite material 9 manufactured in a rectangular parallelepiped shape is partially removed in a groove-like manner.

[0045] The stacking directions of the first heat sink 31 and the second heat sink 32 are both the left-right direction in Fig. 5(A) . Therefore, the thermal conductivity in the up-down direction and the front-back direction (depth direction) is greater than the thermal conductivity in the left-right direction, and the heat generated by the heat source placed on the upper surface can be smoothly dissipated downward, while the entire length of the second heat sink 32 can be effectively utilized while dissipating heat in the front-back direction (depth direction).

[0046] (Embodiment 4) Fig. 5(B) is a perspective view showing a heat sink member 40 according to the fourth embodiment. The heat sink member 40 is composed of a first heat dissipation plate 41 and a second heat dissipation plate 42. The first heat dissipation plate 41 is for placing a heat source on its upper surface. The second heat dissipation plate 42 extends downward from the lower surface of the first heat dissipation plate 41. In this embodiment, the number of second heat dissipation plates 42 is four, and they are arranged side by side in the left-right direction in Fig. 5(B). However, the number of second heat dissipation plates is not particularly limited.

[0047] 5(B), the first heat sink 41 and the second heat sink 42 are joined at a joint 6. The graphite-copper composite material 9 manufactured in a rectangular parallelepiped shape is cut to form the plates 41 and 42, and the upper surface of the second heat sink 42 is joined to the lower surface of the first heat sink 41. Examples of the joining method include brazing and diffusion bonding with copper powder sandwiched between them.

[0048] The stacking directions of the first heat sink 41 and the second heat sink 42 are both the left-right direction in Fig. 5(B) . Therefore, the thermal conductivity in the up-down direction and the front-back direction (depth direction) is greater than the thermal conductivity in the left-right direction, and the heat generated by the heat source placed on the upper surface can be smoothly dissipated downward, while the entire length of the second heat sink 42 can be effectively utilized while dissipating heat in the front-back direction (depth direction).

[0049] (Embodiment 5) Fig. 6(A) is a perspective view showing a heat sink member 50 according to a fifth embodiment. The heat sink member 50 is composed of a first heat dissipation plate 51 and a second heat dissipation plate 52. The first heat dissipation plate 51 has an upper surface on which a heat source is placed. The second heat dissipation plate 52 extends downward from the lower surface of the first heat dissipation plate 51. In this embodiment, the number of second heat dissipation plates 52 is four, and they are arranged in the left-right direction in Fig. 6(A). However, the number of second heat dissipation plates is not particularly limited.

[0050] 6(A), a first heat sink 51 and a second heat sink 52 are joined at a joint 6. A graphite-copper composite material 9 manufactured in a rectangular parallelepiped shape is cut to form the plates 51 and 52, and the upper surface of the second heat sink 52 is joined to the lower surface of the first heat sink 51. Examples of joining methods include brazing and diffusion bonding with copper powder sandwiched between them.

[0051] The stacking direction of the first heat sink 51 is the front-rear direction (depth direction) in FIG. 6(A). Therefore, the thermal conductivity in the up-down direction and the left-right direction is greater than the thermal conductivity in the front-rear direction (depth direction), and the heat generated by the heat source placed on the upper surface can be smoothly dissipated downward, and the four second heat sinks 52 can be effectively utilized while dissipating heat in the left-right direction. On the other hand, the stacking direction of the second heat sink 52 is the left-right direction in FIG. 6(A). Therefore, the thermal conductivity in the up-down direction and the front-rear direction (depth direction) is greater than the thermal conductivity in the left-right direction, and the heat generated by the heat source placed on the upper surface can be smoothly dissipated downward, and the entire length of the second heat sink 52 can be effectively utilized while dissipating heat in the front-rear direction (depth direction).

[0052] (Embodiment 6) Fig. 6(B) is a perspective view showing a heat sink member 60 according to the sixth embodiment. The heat sink member 60 is composed of a first heat dissipation plate 61 and a second heat dissipation plate 62. The first heat dissipation plate 61 is for placing a heat source on its upper surface. The second heat dissipation plate 62 extends downward from the lower surface of the first heat dissipation plate 61. In this embodiment, the number of second heat dissipation plates 62 is four, and they are arranged side by side in the left-right direction in Fig. 6(B). However, the number of second heat dissipation plates is not particularly limited.

[0053] 6(B), the first heat sink 61 and the second heat sink 62 are joined at a joint 6. The graphite-copper composite material 9 manufactured in a rectangular parallelepiped shape is cut to form the plates 61, 62, and the upper surface of the second heat sink 62 is joined to the lower surface of the first heat sink 61. Examples of joining methods include brazing and diffusion bonding with copper powder sandwiched between them.

[0054] The stacking direction of the first heat sink 61 is the left-right direction in FIG. 6(B). Therefore, the thermal conductivity in the up-down direction and the front-back direction (depth direction) is greater than the thermal conductivity in the left-right direction, and the heat generated by the heat source placed on the upper surface is smoothly dissipated downward, and the entire length of the second heat sink 62 can be effectively utilized while dissipating heat in the front-back direction (depth direction). On the other hand, the stacking direction of the second heat sink 62 is the front-back direction (depth direction) in FIG. 6(B). Therefore, the thermal conductivity in the up-down direction and the left-right direction is greater than the thermal conductivity in the front-back direction (depth direction), and the heat generated by the heat source placed on the upper surface is smoothly dissipated downward, and the left and right side surfaces of the second heat sink 62 can be effectively utilized while dissipating heat in the left-right direction.

[0055] (Embodiment 7) Fig. 7(A) is a perspective view showing a heat sink member 70 according to a seventh embodiment. The heat sink member 70 is composed of a first heat dissipation plate 71 and a second heat dissipation plate 72. The first heat dissipation plate 71 has an upper surface on which a heat source is placed. The second heat dissipation plate 72 extends downward from the lower surface of the first heat dissipation plate 71. In this embodiment, the number of second heat dissipation plates 72 is four, and they are arranged side by side in the left-right direction in Fig. 7(A). However, the number of second heat dissipation plates is not particularly limited.

[0056] 7(A), the first heat sink 71 is divided into three parts, a central part 71a on which a heat source is placed, and two side parts 71b, 71b of the central part 71a, which are joined at a joint 6. The first heat sink 71 and the second heat sink 72 are joined at the joint 6. A graphite-copper composite material 9 manufactured in a rectangular parallelepiped shape is cut to form the plates 71a, 71b, 72, and the upper surface of the second heat sink 72 is joined to the lower surface of the first heat sink 71. Examples of the joining method include brazing and diffusion bonding with copper powder sandwiched between them.

[0057] The stacking direction of the center portion 71a of the first heat sink 71 is the left-right direction in FIG. 7(A). Therefore, the thermal conductivity in the up-down direction and the front-back direction (depth direction) is greater than the thermal conductivity in the left-right direction, and the heat generated by the heat source placed on the upper surface is smoothly dissipated downward, and the entire length of the second heat sink 72 can be effectively utilized while dissipating heat in the front-back direction (depth direction). The stacking direction of both side portions 71b, 71b of the first heat sink 71 is the front-back direction (depth direction) in FIG. 7(A). Therefore, the thermal conductivity in the up-down direction and the left-right direction is greater than the thermal conductivity in the front-back direction (depth direction), and the heat generated by the heat source placed on the upper surface is smoothly dissipated downward, and the four second heat sinks 72 can be effectively utilized while dissipating heat in the left-right direction. In this way, in the first heat sink 71 of the heat sink member 70, the stacking direction in the center portion 71a and the stacking direction in both side portions 71b, 71b are perpendicular to each other.

[0058] 7(A), the second heat sink 72 has a larger thermal conductivity in the up-down and left-right directions than in the front-to-back direction (depth direction), and the heat generated by the heat source placed on the upper surface can be smoothly dissipated downward, while the left and right side surfaces of the second heat sink 72 can be effectively utilized while dissipating heat in the left-to-right direction.

[0059] (Embodiment 8) Fig. 7(B) is a perspective view showing a heat sink member 80 according to the eighth embodiment. The heat sink member 80 is composed of a first heat dissipation plate 81 and a second heat dissipation plate 82. The first heat dissipation plate 81 is for placing a heat source on its upper surface. The second heat dissipation plate 82 extends downward from the lower surface of the first heat dissipation plate 81. In this embodiment, the number of second heat dissipation plates 82 is four, and they are arranged side by side in the left-right direction in Fig. 7(B). However, the number of second heat dissipation plates is not particularly limited.

[0060] 7(B), the first heat sink 81 is divided into three sections, a central section 81a on which a heat source is placed, and two side sections 81b, 81b of the central section 81a, which are joined at a joint 6. The first heat sink 81 and the second heat sink 82 are joined at a joint 6. A graphite-copper composite material 9 manufactured in a rectangular parallelepiped shape is cut to form the plates 81a, 81b, 82, and the upper surface of the second heat sink 82 is joined to the lower surface of the first heat sink 81. Examples of the joining method include brazing and diffusion bonding with copper powder sandwiched between them.

[0061] The stacking direction of the center portion 81a of the first heat sink 81 is the front-rear direction (depth direction) in FIG. 7(B). Therefore, the thermal conductivity in the up-down direction and the left-right direction is greater than the thermal conductivity in the front-rear direction (depth direction), and the heat generated by the heat source placed on the upper surface can be smoothly dissipated downward, and the four second heat sinks 82 can be effectively utilized while dissipating heat in the left-right direction. The stacking direction of both side portions 81b, 81b of the first heat sink 81 is the left-right direction in FIG. 7(B). Therefore, the thermal conductivity in the up-down direction and the front-rear direction (depth direction) is greater than the thermal conductivity in the left-right direction, and the heat generated by the heat source placed on the upper surface can be smoothly dissipated downward, and the entire length of the second heat sink 82 can be effectively utilized while dissipating heat in the front-rear direction (depth direction). In this way, in the first heat sink 81 of the heat sink member 80, the stacking direction in the center portion 81a and the stacking direction in both side portions 81b, 81b are perpendicular to each other.

[0062] 7(B), the second heat sink 82 has a stacking direction in the left-right direction. Therefore, the thermal conductivity in the up-down direction and the front-back direction (depth direction) is greater than the thermal conductivity in the left-right direction, and the heat generated by the heat source placed on the upper surface can be smoothly dissipated downward, while the entire length of the second heat sink 82 can be effectively utilized while dissipating heat in the front-back direction (depth direction).

[0063] (Embodiment 9) FIG. 8 is a perspective view showing a heat sink member 90 according to a ninth embodiment. The heat sink member 90 is composed of a first heat dissipation plate 91 and a second heat dissipation plate 92. The first heat dissipation plate 91 has an upper surface on which a heat source is placed. The second heat dissipation plate 92 extends downward from the lower surface of the first heat dissipation plate 91. In this embodiment, the number of second heat dissipation plates 92 is four, and they are arranged in the left-right direction in FIG. 8. However, the number of second heat dissipation plates is not particularly limited. The stacking direction in the heat sink member 90 may be the front-rear direction (depth direction) or the left-right direction, that is, the horizontal direction, and is not particularly shown.

[0064] Between the second heat sinks 92, turbulent flow generating sections 7 having a semicircular cross section are provided to connect the second heat sinks 92. The turbulent flow generating sections 7 generate turbulent flow between adjacent second heat sinks 92. There may be areas between adjacent second heat sinks 92 where the heat transfer efficiency is poor, and in order to suppress this, turbulent flow generating sections 7 generate turbulent flow in the flow of air or water. Note that the turbulent flow generating sections 7 do not need to be members having a semicircular cross section that connect the second heat sinks 92 as in the tenth embodiment, and may be, for example, members that form irregularities on the surface of the second heat sinks 92.

[0065] (Embodiment 10) FIG. 9 is a perspective view showing a heat sink member 100 according to a tenth embodiment. The heat sink member 100 is composed of a first heat dissipation plate 101 and a second heat dissipation plate 102. The first heat dissipation plate 101 is for placing a heat source on the upper surface. The second heat dissipation plate 102 is extended downward from the lower surface of the first heat dissipation plate 101. In this embodiment, the number of second heat dissipation plates 102 is four, and they are arranged in the left-right direction in FIG. 9. However, the number of second heat dissipation plates is not particularly limited. The stacking direction in the heat sink member 100 may be the front-rear direction (depth direction) or the left-right direction, that is, the horizontal direction, and is not particularly shown.

[0066] The upper portions of the left and right ends of the second heat sink 102 extend upward to surround both ends of the first heat sink 101. This allows the heat generated from the heat source to be dissipated without dissipating to the surroundings.

[0067] (Embodiment 11) FIG. 10(A) is a cross-sectional view showing a heat sink member 110 according to an eleventh embodiment. The heat sink member 110 is composed of a first heat dissipation plate 111 and a second heat dissipation plate 112. The first heat dissipation plate 111 is for placing a heat source on the upper surface. The second heat dissipation plate 112 is extended downward from the lower surface of the first heat dissipation plate 111. In this embodiment, the number of second heat dissipation plates 112 is four, and they are arranged in the left-right direction in FIG. 10(A). However, the number of second heat dissipation plates is not particularly limited. The stacking direction in the heat sink member 110 may be the front-rear direction (depth direction) or the left-right direction, that is, the horizontal direction, and is not particularly illustrated.

[0068] A step 200 is provided on the periphery of the upper surface of the first heat dissipation plate 111. The step 200 can be formed by cutting the periphery of the upper surface of the first heat dissipation plate 111. The mounting plate 8 to which the heat sink member 111 is attached does not have a flange, and the lower surface of the mounting plate 8 and the horizontal surface of the step 200 of the first heat dissipation plate 111 are fixed by brazing or soldering. At this time, a gap is provided between the vertical surface of the step 200 of the first heat dissipation plate 111 and the end surface of the mounting plate 8. In this way, by providing a gap using the step, it is possible to prevent the first heat dissipation plate from warping due to thermal expansion.

[0069] (Embodiment 12) FIG. 10B is a cross-sectional view showing a heat sink member 120 according to the twelfth embodiment. The heat sink member 120 is composed of a first heat dissipation plate 121 and a second heat dissipation plate 122. The first heat dissipation plate 121 is for placing a heat source on the upper surface. The second heat dissipation plate 122 is extended downward from the lower surface of the first heat dissipation plate 121. In this embodiment, the number of the second heat dissipation plates 122 is four, and they are arranged in the left-right direction in FIG. 10B. However, the number of the second heat dissipation plates is not particularly limited. The stacking direction in the heat sink member 120 may be the front-rear direction (depth direction) or the left-right direction, that is, the horizontal direction, and is not particularly illustrated.

[0070] A step 200 is provided on the periphery of the upper surface of the first heat dissipation plate 121. The step 200 can be formed by forming the upper part of the first heat dissipation plate 121 as a separate body smaller than the lower part and joining them at the joint 6. The mounting plate 8 to which the heat sink member 121 is attached does not have a flange, and the lower surface of the mounting plate 8 and the horizontal surface of the step 200 of the first heat dissipation plate 121 are fixed by brazing or soldering. At this time, a gap is provided between the vertical surface of the step 200 of the first heat dissipation plate 121 and the end surface of the mounting plate 8. In this way, by providing a gap using the step, it is possible to prevent the first heat dissipation plate from warping due to thermal expansion.

[0071] (Embodiment 13) FIG. 11 shows (A) a front view and (B) a side view of a heat sink member 130 according to a thirteenth embodiment. The heat sink member 130 is composed of a first heat dissipation plate 131 and a second heat dissipation plate 132. The first heat dissipation plate 131 is for placing a heat source on the upper surface. The second heat dissipation plate 132 is extended downward from the lower surface of the first heat dissipation plate 131. In this embodiment, the number of second heat dissipation plates 132 is four, and they are arranged in the left-right direction in FIG. 11(A). However, the number of second heat dissipation plates is not particularly limited. The stacking direction in the heat sink member 130 may be the front-rear direction (depth direction) or the left-right direction, that is, the horizontal direction, and is not particularly shown.

[0072] 11, the first heat sink 131 and the second heat sink 132 are joined at a joint 6. A graphite-copper composite material 9 manufactured in a rectangular parallelepiped shape is cut to form the plates 131 and 132, and the upper surface of the second heat sink 132 is joined to the lower surface of the first heat sink 131. Examples of the joining method include brazing and diffusion bonding with copper powder sandwiched between them.

[0073] A holding portion 13 is provided at the lower ends of the plurality of second heat sinks 132. The holding portion 13 is composed of a main body 13a extending in a direction penetrating the plurality of second heat sinks 132, and a plurality of holding pieces 13b, 13c standing upright from the main body 13a. The lower ends of the second heat sink 132 are inserted between the holding pieces 13b, 13c or between the holding pieces 13c, 13c. The plurality of holding pieces 13b, 13c are arranged so that the lower ends of the second heat sink 132 fit therein, and the holding portion 13 maintains the spacing between the plurality of second heat sinks 132.

[0074] By providing the holding portion 13 to maintain the spacing between the second heat sinks 132, it is possible to prevent the joints 6 between the second heat sinks 132 and the first heat sinks 132 from peeling off when force is applied to the second heat sinks 132. For example, when the heat sink member 130 is handled, it is assumed that strong forces are applied to the second heat sinks 132 from both sides in the directions shown by the arrows in FIG. 11(A). In this case, if the holding portion 13 is not provided, the second heat sinks 132 on both sides would bend inward and the joints 6 would peel off. However, if the holding portion 13 is provided, the strong forces from both sides are absorbed by the holding portion 13 while maintaining the spacing between the second heat sinks 132, so that the joints 6 do not peel off.

[0075] The turbulent flow generating part 7 stands upright from the main body 13a of the holding part 13 and generates turbulent flow between the multiple second heat sinks 132. The action and effect of the turbulent flow generating part 7 is the same as in the ninth embodiment. Of course, it is also possible to provide only the holding piece without providing the turbulent flow generating part 7.

[0076] The heat sink member according to this embodiment is a heat sink member consisting of a first heat sink plate on which a heat source is placed on the upper surface, and a second heat sink plate extending downward from the lower surface of the first heat sink plate. The first heat sink plate and the second heat sink plate are graphite-copper composite materials containing flake graphite particles stacked via a copper layer, and having a higher thermal conductivity in a direction perpendicular to the stacking direction of the flake graphite particles than in the stacking direction. The flake graphite particles are arranged so that the stacking direction is horizontal. Therefore, the arrangement is such that the thermal conductivity in the vertical direction is high, and heat generated from the heat source placed on the upper surface can be effectively dissipated in the vertical direction.

[0077] Furthermore, when the first heat sink plate and multiple second heat sink plates are integrally molded, there is no need to join the heat sink plates together, and heat can be dissipated smoothly at the boundary between the first heat sink plate and the second heat sink plate.

[0078] Furthermore, when a first heat sink plate and multiple second heat sink plates are joined together, by making the first heat sink plate and the second heat sink plate separate bodies, it is possible to combine the directionality of the magnitude of thermal conduction in various ways.

[0079] Furthermore, when the first heat dissipation plate is arranged so that the stacking direction of the flake graphite particles in the central portion where the heat source is placed is perpendicular to the stacking direction of the flake graphite particles on both sides of the central portion, the directionality of the magnitude of thermal conduction can be changed between the central portion and both sides, thereby varying the vertical heat dissipation and horizontal heat dissipation as necessary.

[0080] Furthermore, if a turbulence generating section that generates turbulence between multiple second heat sinks is provided, turbulence can be generated in the fluid (air, water) between the second heat sinks, thereby effectively cooling the second heat sinks.

[0081] Furthermore, when the second heat sink is extended upward so as to surround both ends of the first heat sink, the heat generated by the heat source can be dissipated without being dissipated to the surroundings.

[0082] In addition, if a step is provided on the peripheral edge of the upper surface of the first heat sink, a gap can be created between the mounting plate and the first heat sink using the step, thereby preventing warping of the first heat sink due to thermal expansion.

[0083] Furthermore, if a holding portion is provided to maintain the spacing between multiple second heat sinks, it is possible to prevent the joint between the second heat sink and the first heat sink from peeling off due to force being applied to the second heat sink.

[0084] Thus, according to the present invention, a heat sink member having excellent heat dissipation properties can be provided by using a graphite-copper composite material in which flake graphite particles are laminated.

[0085] Although the heat sink member according to the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various other modifications are possible. [Explanation of symbols]

[0086] 1. Flake-like graphite particles 2 layers 3 Mounting plate 4 Flanges 5 holes 6 Joint 7 Turbulence generation section 8 Mounting plate 9 Graphite-copper composite material 13 Holding part 10,20,30,40,50,60,70,80,90 Heat sink material 11, 21, 31, 41, 51, 61, 71, 81, 91 First heat sink 12,22,32,42,52,62,72,82,92 Second heat sink 100, 110, 120 130 Heat sink material 101,111,121 131 First heat sink 102,112,122 132 Second heat sink 200 steps

Claims

1. A heat sink member including a first heat dissipation plate on an upper surface of which a heat source is placed, and a second heat dissipation plate extending downward from a lower surface of the first heat dissipation plate, The first heat sink member and the second heat sink member are made of a graphite-copper composite material containing flake graphite particles stacked via a copper layer, the thermal conductivity of which in a direction perpendicular to the stacking direction of the flake graphite particles is greater than the thermal conductivity in the stacking direction, and the stacking direction of the flake graphite particles is arranged so that it is horizontal.

2. 2. The heat sink member according to claim 1, wherein the first heat dissipation plate and the plurality of second heat dissipation plates are integrally formed.

3. 2. The heat sink member according to claim 1, wherein the first heat dissipation plate and the plurality of second heat dissipation plates are joined together.

4. The heat sink member according to claim 3, characterized in that the first heat dissipation plate is arranged so that the stacking direction of the flake graphite particles in the central portion where the heat source is placed is perpendicular to the stacking direction of the flake graphite particles on both sides of the central portion.

5. 2. The heat sink member according to claim 1, further comprising a turbulence generating portion for generating turbulence between the second heat sink plates.

6. 2. The heat sink member according to claim 1, wherein the second heat sink plate extends upward so as to surround both ends of the first heat sink plate.

7. 2. The heat sink member according to claim 1, wherein a step is provided on the peripheral edge of the upper surface of the first heat sink.

8. 4. The heat sink member according to claim 3, further comprising a holding portion for holding the spacing between the second heat sink plates.

Images