Heat sink

Abstract

To provide a heat sink with a heat transport member that can prevent the heat transport member from drying out even if an environmental temperature is lower than the fusion point of working fluid of the heat transport member without spoiling heat transport characteristics, and also smoothly actuates the heat transport member.SOLUTION: A heat sink comprises a heat transport member which has a heat reception part thermally connected to a heating body, and a heat radiation fin group which is thermally connected to a heat radiation part of the heat transport member and has a plurality of heat radiation fins arranged, wherein the heat transport member communicates from the heat reception part to the heat radiation part, and also has an internal space in which the working fluid is charged, and a heat transport body which has an internal space in which the working fluid is charged is provided at a connection part between the heat transport member and the heat radiation fins.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a heat sink for cooling heat generating bodies such as electric components and electronic components.

Background Art

[0002] With the increasing functionality of electronic devices, a large number of components, including heat generating bodies such as electronic components, are densely mounted inside the electronic devices. Also, with the increasing functionality of electronic devices, the amount of heat generated by heat generating bodies such as electronic components is increasing. As a means for cooling heat generating bodies such as electronic components housed inside an electronic device, heat transport members such as heat pipes and vapor chambers having an internal space in which a working fluid is enclosed under reduced pressure, and heat sinks provided with the above-described heat transport members such as heat sinks and vapor chambers may be used.

[0003] When the environmental temperature of a heat sink or a vapor chamber is lower than the melting point of a working fluid such as water, the working fluid enclosed in the internal space of the heat sink or the vapor chamber is frozen. Therefore, when the environmental temperature of the heat sink or the vapor chamber is lower than the melting point of the working fluid, when the heat sink or the vapor chamber receives heat from a heat generating body to be cooled, the working fluid is in a frozen state and the heat sink or the vapor chamber starts up.

[0004] As shown in FIG. 8, in a conventional heat sink 101, when a heat transport section 110 such as a heat sink or a vapor chamber receives a predetermined amount of heat Qin from a heat generating body 100 at a heat receiving section 141 with the working fluid in a frozen state, at the heat receiving section 141, the solid-phase working fluid 200 in a frozen state undergoes a phase change to a gaseous-phase working fluid 201. The gaseous-phase working fluid 201 flows from the heat receiving section 141 through a heat insulating section 142 of the heat transport section 110 to a heat radiating section 143 of the heat transport section 110 to which a heat radiating fin group 120 is directly connected. The gaseous-phase working fluid 201 that has flowed to the heat radiating section 143 undergoes a phase change to a liquid-phase working fluid 202 by the heat exchange action of the heat radiating fin group 120 and releases a predetermined amount of heat Qout as latent heat.

[0005] However, when the environmental temperature of the heat sink 101 is lower than the melting point of the working fluid, in the heat dissipation section 143, the liquid-phase working fluid 202 freezes and undergoes a phase change to the solid-phase working fluid 200. If the liquid-phase working fluid 202 freezes in the heat dissipation section 143, the working fluid cannot flow back from the heat dissipation section 143 to the heat receiving section 141, and the heat transport section 110 will dry out. Further, when the working fluid in the heat transport section 110 is frozen, after the solid-phase working fluid 202 stored in the heat dissipation section 143 changes to the liquid-phase working fluid 202, the liquid-phase working fluid 202 flows back from the heat dissipation section 143 to the heat receiving section 141, so it takes time to start the heat sink and the vapor chamber.

[0006] Therefore, in order to prevent the freezing of the working fluid, it has been proposed to use water containing glycols as the working fluid of the heat pipe (Patent Document 1). In Patent Document 1, by using water containing glycols as the working fluid, the melting point is lowered compared to pure water, so even if the usage environment of the heat sink and the vapor chamber is low temperature, the working fluid does not freeze and flows back from the heat dissipation section to the heat receiving section to prevent dry-out.

[0007] However, in Patent Document 1, since an organic solvent such as glycols is mixed with the water which is the working fluid, there is a problem that the heat transport characteristics of the heat pipe deteriorate. Further, in Patent Document 1, since the organic solvent is enclosed in the internal space of the heat pipe, there is a problem that the long-term reliability of the heat transport characteristics deteriorates.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] In view of the above circumstances, an object of the present invention is to provide a heat sink provided with a heat transport member that can prevent dry-out of the heat transport member and can smoothly start up the heat transport member even when the environmental temperature is lower than the melting point of the working fluid of the heat transport member without impairing the heat transport characteristics.

Means for Solving the Problems

[0010] The gist of the configuration of the heat sink of the present invention is as follows. [1] A heat transport member having a heat receiving portion that is thermally connected to a heat generating body, and a heat radiation fin group in which a plurality of heat radiation fins are arranged and that is thermally connected to the heat radiation portion of the heat transport member, The heat transport member has an internal space that communicates from the heat receiving portion to the heat radiation portion and in which a working fluid is enclosed, A heat sink in which a heat transport body having an internal space in which a working fluid is enclosed is provided at a connection portion between the heat transport member and the heat radiation fin. [2] The heat sink according to [1], wherein the heat transport body is thermally connected to the heat transport member and the heat radiation fin. [3] The heat sink according to [1] or [2], wherein the heat transport body is a heat pipe or a vapor chamber. [4] The heat sink according to any one of [1] to [3], wherein the heat transport body is provided over the entire area of the connection portion. [5] The heat sink according to any one of [1] to [4], wherein the heat transport body has a bent portion at a central portion in the extending direction of the heat transport body, one end of the heat transport body is located at the connection portion, and the other end of the heat transport body is thermally connected to the tip of the heat radiation fin. [6] The heat sink according to any one of [1] to [5], wherein the heat transport body is not provided at the heat receiving portion and the heat insulating portion of the heat transport member located between the heat receiving portion and the heat radiation portion. [7] The heat sink according to any one of [1] to [6], wherein the internal space of the heat transport member is integral. [8] The heat sink according to any one of [1] to [6], wherein the heat transfer member is a heat pipe group in which a plurality of heat pipes are arranged in parallel. [9] The heat sink according to any one of [1] to [8], wherein the heat radiating portion of the heat transfer member is wider than the heat receiving portion.

[0011] In the above aspect, among the heat transfer members, the portion thermally connected to the heat generating body to be cooled functions as the heat receiving portion, and the portion thermally connected to the heat radiating fins functions as the heat radiating portion of the heat transfer member. A heat transfer body, which is a member different from the heat transfer member, is provided at the connection portion between the heat transfer member and the heat radiating fins in the heat radiating portion. The heat transfer body has an internal space filled with a working fluid. Also, among the heat transfer members, the portion between the heat receiving portion and the heat radiating portion functions as a heat insulating portion. In the heat receiving portion of the heat transfer member, the working fluid receives heat from the heat generating body and undergoes a phase change from the liquid phase to the gas phase, and in the heat radiating portion of the heat transfer member, the gaseous working fluid releases latent heat and undergoes a phase change from the gas phase to the liquid phase. Also, in the above aspect, the gaseous working fluid flows from the heat receiving portion of the heat transfer member, through the heat insulating portion, to the heat radiating portion, and the liquid-phase working fluid flows from the heat radiating portion of the heat transfer member, through the heat insulating portion, to the heat receiving portion. Therefore, the heat of the heat generating body is transported by the heat transfer member from the heat receiving portion of the heat transfer member, through the heat insulating portion, to the heat radiating portion of the heat transfer member.

[0012] Also, in the above aspect, since the heat transfer body is provided between the heat radiating portion of the heat transfer member and the heat radiating fins, heat is transferred from the heat radiating portion of the heat transfer member to the heat radiating fins through the heat transfer body.

Advantages of the Invention

[0013] In the aspect of the heat sink of the present invention, a heat transporter having an internal space in which a working fluid is enclosed is provided at the connection part between the heat transport member and the heat radiation fins. When the environmental temperature is lower than the melting point of the working fluid, the working fluid of the heat transporter freezes. Therefore, the heat transporter functions as a heat insulator, suppressing heat transfer from the heat dissipation part of the heat transport member to the heat radiation fins. When the environmental temperature is lower than the melting point of the working fluid of the heat transport member, heat transfer from the heat dissipation part of the heat transport member to the heat radiation fins is suppressed, preventing the liquid-phase working fluid of the heat transport member from freezing and undergoing a phase change to a solid-phase working fluid at the heat dissipation part of the heat transport member. Even when the environmental temperature is lower than the melting point of the working fluid of the heat transport member, freezing of the liquid-phase working fluid of the heat transport member is prevented, so that the working fluid of the heat transport member can reflux from the heat dissipation part of the heat transport member to the heat receiving part, preventing dry-out of the heat transport member. Also, in the aspect of the heat sink of the present invention, when the environmental temperature is higher than the melting point of the working fluid of the heat transport member (for example, normal temperature), the working fluid of the heat transporter is not frozen, so heat transfer from the heat dissipation part of the heat transport member to the heat radiation fins via the heat transporter is smoothed. Also, due to the heat transport characteristics of the heat transporter, the heat dissipation part of the heat transport member is homogenized throughout, improving the fin efficiency of the heat radiation fins, and the heat sink exhibits excellent cooling performance.

[0014] Furthermore, in the aspect of the heat sink of the present invention, when the environmental temperature is higher than the melting point of the working fluid of the heat transport member (for example, normal temperature), since the working fluid of the heat transporter is not frozen, heat transfer from the heat dissipation part of the heat transport member to the heat radiation fins via the heat transporter is smoothed. Also, due to the heat transport characteristics of the heat transporter, the heat dissipation part of the heat transport member is homogenized throughout, improving the fin efficiency of the heat radiation fins, and the heat sink exhibits excellent cooling performance.

[0015] From the above, according to the aspect of the heat sink of the present invention, without impairing the heat transport characteristics, even when the environmental temperature is lower than the melting point of the working fluid of the heat transport member, dry-out of the heat transport member can be prevented, and the heat transport member can be started up smoothly.

[0016] According to an aspect of the heat sink of the present invention, since the heat transfer body is thermally connected to the heat transfer member and the heat radiation fins, when the ambient temperature is lower than the melting point of the working fluid, heat transfer from the heat radiating portion of the heat transfer member to the heat radiation fins is surely suppressed, and it is surely possible to prevent the working fluid in the liquid phase of the heat transfer member from freezing at the heat radiating portion of the heat transfer member.

[0017] According to an aspect of the heat sink of the present invention, since the heat transfer body is provided over the entire connection portion between the heat transfer member and the heat radiation fins, when the ambient temperature is lower than the melting point of the working fluid, the suppression effect of heat transfer from the heat radiating portion of the heat transfer member to the heat radiation fins is further improved, and it is further surely possible to prevent the working fluid in the liquid phase of the heat transfer member from freezing at the heat radiating portion of the heat transfer member.

[0018] According to an aspect of the heat sink of the present invention, the heat transfer body has a bent portion at the central portion in the extending direction of the heat transfer body, one end of the heat transfer body is located at the connection portion, and the other end of the heat transfer body is thermally connected to the tip of the heat radiation fin. Therefore, when the ambient temperature is normal temperature, heat is also transferred from the heat radiating portion of the heat transfer member to the tip of the heat radiation fin due to the heat transfer characteristics of the heat transfer body. Therefore, according to an aspect of the heat sink of the present invention, not only heat transfer from the heat radiating portion of the heat transfer member to the heat radiation fins but also heat transfer from the heat radiating portion of the heat transfer member to the tip of the heat radiation fin improves the fin efficiency of the heat radiation fins and further improves the cooling performance of the heat sink.

[0019] According to an aspect of the heat sink of the present invention, since the internal space of the heat transfer member is integrated, even if heat generation unevenness occurs in the heat generating body, the entire heat generating body can be cooled uniformly.

[0020] According to an aspect of the heat sink of the present invention, since the heat transfer member is a heat pipe group in which a plurality of heat pipes are arranged in parallel, the heat transfer characteristics of the heat transfer member are further surely improved.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0022] Hereinafter, the heat sink according to the embodiment of the present invention will be described with reference to the drawings. First, the heat sink according to the first embodiment of the present invention will be described. FIG. 1 is a perspective view for explaining the outline of the heat sink according to the first embodiment of the present invention. FIG. 2 is a side cross-sectional view for explaining the outline of the heat sink according to the first embodiment of the present invention. FIG. 3 is a plan view for explaining the outline of the heat sink according to the first embodiment of the present invention.

[0023] As shown in FIG. 1, the heat sink 1 according to the first embodiment of the present invention includes a heat transport member 10 having a heat receiving portion (evaporation portion) 41 that is thermally connected to the heat generating body 100, and a heat dissipation fin group 20 that is thermally connected to the heat transport member 10. In the heat sink 1, there is one heat transport member 10. The portion of the heat transport member 10 to which the heat dissipation fin group 20 is thermally connected is the heat dissipation portion (condensation portion) 42. At the heat dissipation portion 42 of the heat transport member 10, the heat dissipation fin group 20 is thermally connected to the heat transport member 10.

[0024] The heat transfer member 10 includes a container 19 having a hollow cavity and a working fluid flowing through the cavity. A wick structure (not shown) having capillary force is housed in the cavity. The container 19 is formed by overlapping one plate-like body 11 and the other plate-like body 12 facing the one plate-like body 11.

[0025] One plate-like body 11 is a plate-like member having side walls erected from a flat surface portion at the edge of the flat surface portion. The other plate-like body 12 is also a plate-like member having side walls erected from a flat surface portion at the edge of the flat surface portion. Therefore, both the one plate-like body 11 and the other plate-like body 12 are in a concave shape. By overlapping the concave one plate-like body 11 and the concave other plate-like body 12, the container 19 having a cavity is formed. Therefore, the shape of the container 19 is planar, and the heat transfer member 10 has a vapor chamber configuration. The cavity, which is the internal space of the container 19, is sealed from the external environment and is depressurized by a degassing process.

[0026] The internal space of the heat transfer member 10 communicates from the heat receiving portion 41 to the heat radiating portion 42, and a working fluid is enclosed in the internal space of the heat transfer member 10. Further, in the heat sink 1, the internal space of the heat transfer member 10 is integrated as a whole.

[0027] Among the outer surfaces of the container 19, the portion where the heat generating body 100, which is the object to be cooled, is thermally connected is the heat receiving portion 41. When the heat generating body 100 is thermally connected to the container 19, the heat generating body 100 is cooled by the cooling action of the heat sink 1. In the heat transfer member 10, since the heat generating body 100 is thermally connected to one end, one end of the heat transfer member 10 serves as the heat receiving portion 41. Further, the heat generating body 100 is thermally connected to the one plate-like body 11 among the outer surfaces of the container 19.

[0028] The heat transfer member 10 extends in a predetermined direction from the position of the heating element 100, and a heat radiation fin group 20 is thermally connected to the other end facing one end of the container 19. The other end of the heat transfer member 10 to which the heat radiation fin group 20 is thermally connected functions as a heat radiation part 42 of the heat transfer member 10.

[0029] The heat radiation part 42 of the heat transfer member 10 is wider than the heat receiving part 41. In the heat sink 1, the heat radiation part 42 of the heat transfer member 10 extends in a direction substantially orthogonal to the heat transfer direction H of the heat transfer member 10 (width direction W) along the plane direction of the heat transfer member 10. Also, the heat radiation part 42 of the heat transfer member 10 extends in two directions. In the heat sink 1, since the extending direction of the heat radiation part 42 is not parallel to the heat transfer direction H of the heat transfer member 10, the heat transported from the heat transfer member 10 is diffused by the heat radiation part 42 in a direction different from the extending direction of the heat transfer member 10. Therefore, an increase in the dimension of the heat sink 1 in the heat transfer direction H of the heat transfer member 10 can be prevented, and space saving of the heat sink 1 can be achieved. Also, since the heat radiation part 42 of the heat transfer member 10 is wider than the heat receiving part 41, the number of heat radiation fins 21 constituting the heat radiation fin group 20 can be increased.

[0030] In the heat transfer member 10, an intermediate part in the heat transfer direction H, which is located between the heat receiving part 41 located at one end of the container 19 and the heat radiation part 42 located at the other end of the container 19, functions as a heat insulation part 43. The heat insulation part 43 of the heat transfer member 10 is a part where neither the heat radiation fin group 20 nor the heating element 100 is thermally connected, and is a part where active heat input to the heat transfer member 10 and active heat radiation from the heat transfer member 10 do not occur. The heat transmitted from the heating element 100 to the heat receiving part 41 is transported from the heat receiving part 41 to the heat radiation part 42 through the heat insulation part 43 along the extending direction of the heat transfer member 10.

[0031] In the heat sink 1, the dimension of the heat insulation part 43 in the width direction W is substantially the same as the dimension of the heat receiving part 41 in the width direction W. Also, in the heat transfer member 10, the heat receiving part 41, the heat insulation part 43, and the heat radiation part 42 extend along the same plane.

[0032] In the heat sink 1, the heat radiation fin group 20 is formed by a plurality of heat radiation fins 21, 21, 21 ··· standing on the outer surface of the heat radiation part 42. From the above, a heat radiation fin group 20 in which a plurality of heat radiation fins 21, 21, 21 ··· are arranged is thermally connected to the heat radiation part 42 of the heat transport member 10. The heat radiation fins 21 are attached to the outer surface of the heat radiation part 42 such that their main surfaces are substantially parallel to the heat transport direction H of the heat transport member 10. A plurality of heat radiation fins 21, 21, 21 ··· are arranged in parallel at predetermined intervals along the heat radiation part 42 extending in a direction substantially orthogonal to the heat transport direction H of the heat transport member 10, thereby forming the heat radiation fin group 20. The heights of the plurality of heat radiation fins 21, 21, 21 ··· forming the heat radiation fin group 20 are all substantially the same.

[0033] The heat radiation fin group 20 is provided on one plate-like body 11 and the other plate-like body 12 of the container 19, respectively. From the above, at the other end in the heat transport direction H of the heat transport member 10, the heat radiation fins 21 are thermally connected to the container 19 in a state of being divided on both sides of the container 19 (that is, one plate-like body 11 and the other plate-like body 12).

[0034] As shown in FIGS. 1 to 3, in the heat sink 1, a heat transport body 30 is provided at the connection part 31 between the heat transport member 10 and the heat radiation fins 21 (heat radiation fin group 20). The heat transport body 30 is a member having an internal space filled with a working fluid. The internal space of the heat transport body 30 is depressurized by a degassing process. From the above internal structure, the heat transport body 30 is a member having a heat transport function. Also, the heat transport body 30 is a separate member from the heat transport member 10, and the internal space of the heat transport body 30 does not communicate with the internal space of the heat transport member 10.

[0035] The heat transfer body 30 is interposed between the heat transfer member 10 and the heat dissipation fins 21 (heat dissipation fin group 20). Further, the heat transfer body 30 is in contact with the heat transfer member 10 and the heat dissipation fins 21 (heat dissipation fin group 20), and is thermally connected to the heat transfer member 10 and the heat dissipation fins 21 (heat dissipation fin group 20). At the base of the heat dissipation fin 21 in contact with the heat transfer body 30, a notch 22 corresponding to the shape and size of the cross section of the heat transfer body 30 is provided at a position corresponding to the position of the heat transfer body 30. The heat transfer body 30 is inserted into the notch 22 and the space surrounded by the outer surface of the container 19. By providing the notch 22 in the heat dissipation fin 21, the thermal connectivity between the heat transfer body 30 and the heat dissipation fins 21 (heat dissipation fin group 20) and the thermal connectivity between the heat transfer member 10 and the heat dissipation fins 21 (heat dissipation fin group 20) are improved.

[0036] The heat transfer body 30 extends along the outer surface of the heat transfer member 10 in contact with the outer surface of the heat transfer member 10. In the heat sink 1, the heat transfer body 30 extends in a direction substantially orthogonal (width direction W) to the heat transfer direction H of the heat transfer member 10 along the planar direction of the heat dissipation portion 42 which is wider than the heat receiving portion 41. The heat transfer body 30 extends linearly from one end 51 to the other end 52 in the width direction W of the heat dissipation portion 42. One end 33 of the heat transfer body 30 is located at one end 51 in the width direction W of the heat dissipation portion 42, and the other end 34 of the heat transfer body 30 is located at the other end 52 in the width direction W of the heat dissipation portion 42.

[0037] Also, the heat transfer body 30 is provided in a partial region of the heat dissipation portion 42 of the heat transfer member 10 in the heat transfer direction H. In the heat sink 1, the heat transfer body 30 is provided at the center of the heat dissipation portion 42 in the heat transfer direction H, and the heat transfer body 30 is not provided at both ends of the heat dissipation portion 42 in the heat transfer direction H. From the above, the notch 22 is provided at the center of the base of the heat dissipation fin 21, and the notch 22 is not provided at both ends of the base of the heat dissipation fin 21. Therefore, at the center of the base of the heat dissipation fin 21, the heat dissipation fin 21 is in contact with the heat transfer body 30, and at both ends of the base of the heat dissipation fin 21, the heat dissipation fin 21 is in contact with the container 19.

[0038] Further, the heat transfer medium 30 is provided on the outer surfaces of one plate-like body 11 and the other plate-like body 12 of the container 19, respectively. In the heat sink 1, the heat transfer medium 30 provided on the outer surface of one plate-like body 11 and the heat transfer medium 30 provided on the outer surface of the other plate-like body 12 are provided at positions that overlap in a plan view with the container 19 interposed therebetween.

[0039] In the heat sink 1, the heat transfer medium 30 is a heat pipe 32. The shape of the heat pipe 32 is a tubular body. Also, the shape of the heat pipe 32 in the longitudinal direction is linear. The internal space of the heat pipe 32 is sealed from the external environment and is depressurized by a degassing process. The heat pipe 32 is a heat transfer medium 30 that transports heat along its longitudinal direction.

[0040] As shown in FIGS. 1 to 3, the heat transfer medium 30 is composed of a plurality of heat pipes 32, 32, 32,.... In FIGS. 1 to 3, for convenience of explanation, two heat pipes 32 are provided on the outer surfaces of one plate-like body 11 and the other plate-like body 12, respectively. The plurality of heat pipes 32, 32, 32,... are arranged in parallel along the heat transfer direction H of the heat transfer member 10.

[0041] The heat transfer medium 30 is not provided in the heat receiving portion 41 of the heat transfer member 10 and the heat insulating portion 43 of the heat transfer member 10 located between the heat receiving portion 41 and the heat radiating portion 42. The heat transfer medium 30 is provided only in the heat radiating portion 42 of the heat transfer member 10 and does not extend to the heat insulating portion 43 and the heat receiving portion 41.

[0042] In the heat sink 1, the heat of the heating element 100 is transported from the heat receiving portion 41, through the heat insulating portion 43, to the heat radiating portion 42 to which the heat radiating fin group 20 is thermally connected. The heat transported to the heat radiating portion 42 is transmitted from the container 19 to the heat radiating fins 21 through the heat pipe 32 which is the heat transfer medium 30, or is transmitted directly from the container 19 to the heat radiating fins 21. The heat transmitted to the heat radiating fins 21 is released to the external environment of the heat sink 1 by the heat exchange action of the heat radiating fins 21.

[0043] Inside the container 19, a wick structure (not shown) that generates capillary force is provided. The wick structure is provided, for example, over the entire inner surface of the container 19. Due to the capillary force of the wick structure, the working fluid that has undergone a phase change from the gas phase to the liquid phase at the heat dissipation part 42 of the heat transport member 10 refluxes from the heat dissipation part 42 of the heat transport member 10 to the heat receiving part 41 via the heat insulation part 43.

[0044] The type of the wick structure is not particularly limited, and examples thereof include a sintered body of metal powder such as copper powder, a metal mesh made of metal wires, a non-woven fabric, grooves (a plurality of fine grooves) formed on the inner surface of the container 19, or a combination thereof.

[0045] The gaseous working fluid can flow through the inside of the container 19 by a vapor flow path (not shown). The vapor flow path is the internal space of the container 19 and extends over the entire container 19. Therefore, the gaseous working fluid can flow over the entire container 19. Further, in the vapor flow path, pillars (not shown) as support parts may be provided as necessary to maintain the internally depressurized space of the container 19. The pillars are not particularly limited, and examples thereof include pillars made of a composite material in which a wick structure is coated around a columnar metal member (for example, a copper member) in order to reduce the flow path resistance when the liquid-phase working fluid refluxes, and sintered bodies of metal powder such as columnar copper powder.

[0046] Examples of the material of the container 19 include stainless steel, copper, copper alloy, aluminum, aluminum alloy, tin, tin alloy, titanium, titanium alloy, nickel, nickel alloy, etc. Examples of the material of the heat dissipation fins 21 include metal materials such as copper, copper alloy, aluminum, and aluminum alloy.

[0047] The working fluid enclosed in the internal space of the container 19 can be appropriately selected according to the compatibility with the material of the container 19, and examples thereof include water.

[0048] As the material of the container of the heat pipe 32, similar to the container 19 of the heat transport member 10, for example, stainless steel, copper, copper alloy, aluminum, aluminum alloy, tin, tin alloy, titanium, titanium alloy, nickel, nickel alloy, etc. can be mentioned. As the working fluid enclosed in the internal space of the container of the heat pipe 32, it can be appropriately selected according to the compatibility with the material of the container. For example, similar to the heat transport member 10, water can be mentioned. That is, the type of the working fluid of the heat transport body 30 can be the same as the type of the working fluid of the heat transport member 10.

[0049] Also, the heat sink 1 may be forced air-cooled by a blower fan (not shown) as necessary. By supplying the cooling air from the blower fan along the main surface of the heat radiation fins 21, the cooling function of the heat radiation fin group 20 is improved.

[0050] Next, the mechanism of the cooling function of the heat sink 1 will be described. First, a heat generating body 100, which is a body to be cooled, is thermally connected to one end of the container 19 of the heat transport member 10. When the heat transport member 10 receives heat from the heat generating body 100 at the heat receiving portion 41 located at one end of the container 19, heat is transferred from the heat generating body 100 to the liquid-phase working fluid enclosed in the internal space of the container 19 at the heat receiving portion 41 of the heat transport member 10, and the liquid-phase working fluid undergoes a phase change into a gas-phase working fluid. The gas-phase working fluid that has undergone a phase change from the liquid phase flows through the vapor flow path from the heat receiving portion 41 of the heat transport member 10, through the heat insulating portion 43 located at the central portion of the heat transport member 10, to the heat radiating portion 42 located at the other end of the container 19. By the gas-phase working fluid flowing from the heat receiving portion 41 located at one end of the container 19, through the heat insulating portion 43, to the heat radiating portion 42 located at the other end of the container 19, the heat from the heat generating body 100 is transported from one end of the heat transport member 10 to the other end. The gas-phase working fluid that has flowed from one end to the other end of the heat transport member 10 releases latent heat by the heat exchange action of the heat radiating fin group 20 that is thermally connected to the heat radiating portion 42 of the heat transport member 10, and undergoes a phase change from the gas phase to the liquid phase. The latent heat released from the working fluid is transmitted from the container 19 of the heat transport member 10 to the heat radiating fin group 20. The heat transmitted from the container 19 to the heat radiating fin group 20 is released from the heat radiating fin group 20 to the external environment of the heat sink 1. The working fluid that has released latent heat and undergone a phase change from the gas phase to the liquid phase flows back from the heat radiating portion 42 of the heat transport member 10, through the heat insulating portion 43, to the heat receiving portion 41 by the capillary force of the wick structure provided inside the container 19.

[0051] In the heat sink 1 according to the first embodiment of the present invention, a heat pipe 32, which is a heat transport body 30 having an internal space filled with a working fluid, is separately provided at a connection portion 31 between the heat transport member 10 and the heat radiation fins 21 (heat radiation fin group 20). When the ambient temperature of the heat sink 1 is lower than the melting point of the working fluid, the working fluid in the heat pipe 32 freezes. Therefore, the heat pipe 32 with the frozen working fluid functions as a heat insulating material, and as a result, the heat transfer from the heat radiation portion 42 of the heat transport member 10 to the heat radiation fins 21 (heat radiation fin group 20) is suppressed. When the ambient temperature of the heat sink 1 is lower than the melting point of the working fluid in the heat transport member 10, the heat transfer from the heat radiation portion 42 of the heat transport member 10 to the heat radiation fins 21 (heat radiation fin group 20) is suppressed by the heat pipe 32, thereby preventing the working fluid in the liquid phase of the heat transport member 10 from freezing and undergoing a phase change to the solid phase of the working fluid at the heat radiation portion 42 of the heat transport member 10. Thus, even when the ambient temperature of the heat sink 1 is lower than the melting point of the working fluid, the freezing of the working fluid in the liquid phase of the heat transport member 10 is prevented, so that the working fluid of the heat transport member 10 can reflux from the heat radiation portion 42 to the heat receiving portion 41 of the heat transport member 10, preventing the dry-out of the heat transport member 10. Further, in the heat sink 1, when the ambient temperature of the heat sink 1 is higher than the melting point of the working fluid in the heat transport member 10 (for example, normal temperature), the working fluid in the heat pipe 32 is not frozen, so that the heat transfer from the heat radiation portion 42 of the heat transport member 10 to the heat radiation fins 21 (heat radiation fin group 20) through the heat pipe 32 is smoothed. Also, due to the heat transport characteristics of the heat pipe 32, the heat radiation portion 42 of the heat transport member 10 is made uniform in temperature over the whole, so that the fin efficiency of the heat radiation fins 21 (heat radiation fin group 20) is improved, and the heat sink 1 exhibits excellent cooling performance.

[0052] Further, in the aspect of the heat sink 1, when the ambient temperature of the heat sink 1 is higher than the melting point of the working fluid in the heat transport member 10 (for example, normal temperature), the working fluid in the heat pipe 32 is not frozen, so that the heat transfer from the heat radiation portion 42 of the heat transport member 10 to the heat radiation fins 21 (heat radiation fin group 20) through the heat pipe 32 is smoothed. Also, due to the heat transport characteristics of the heat pipe 32, the heat radiation portion 42 of the heat transport member 10 is made uniform in temperature over the whole, so that the fin efficiency of the heat radiation fins 21 (heat radiation fin group 20) is improved, and the heat sink 1 exhibits excellent cooling performance.

[0053] From the above, according to the aspect of the heat sink 1, even if the environmental temperature of the heat sink 1 is lower than the melting point of the working fluid of the heat transport member 10 without impairing the heat transport characteristics of the heat transport member 10, the dry-out of the heat transport member 10 can be prevented, and the heat transport member 10 can be smoothly started up.

[0054] Also, according to the aspect of the heat sink 1, since the heat pipe 32 which is the heat transport body 30 is thermally connected to the heat transport member 10 and the radiation fins 21 (radiation fin group 20), when the environmental temperature of the heat sink 1 is lower than the melting point of the working fluid of the heat transport member 10, the heat transfer from the heat radiation part 42 of the heat transport member 10 to the radiation fins 21 (radiation fin group 20) is surely suppressed, and it is surely possible to prevent the liquid-phase working fluid of the heat transport member 10 from freezing at the heat radiation part 42 of the heat transport member 10. Also, according to the aspect of the heat sink 1, at both ends of the base of the radiation fin 21, since the radiation fin 21 is in contact with the container 19, when the environmental temperature of the heat sink 1 is at room temperature, the heat transfer property from the heat radiation part 42 of the heat transport member 10 to the radiation fins 21 (radiation fin group 20) is further improved.

[0055] Also, according to the aspect of the heat sink 1, since the internal space of the heat transport member 10 is integral, even if heat generation unevenness occurs in the heat generating body 100, the entire heat generating body 100 can be cooled uniformly.

[0056] Next, the heat sink according to the second embodiment example of the present invention will be described in detail. Since the heat sink according to the second embodiment example has the same main components as the heat sink according to the first embodiment example, the same components as those of the heat sink according to the first embodiment example will be described using the same reference numerals. FIG. 4 is a side cross-sectional view for explaining the outline of the heat sink according to the second embodiment example of the present invention.

[0057] In the heat sink 1 according to the first embodiment example, the heat pipe 32 as the heat transfer medium 30 was provided in a partial region of the connection part 31. However, as shown in FIG. 4, in the heat sink 2 according to the second embodiment example, the heat pipe 32 as the heat transfer medium 30 is provided in the entire area of the connection part 31.

[0058] As shown in FIG. 4, in the heat sink 2, the heat pipes 32 are provided at the central part and both ends of the heat radiation part 42 in the heat transfer direction H. From the above, in the heat sink 2, the heat transfer medium 30 is composed of a plurality of heat pipes 32, 32, 32... more than those in the heat sink 1. In FIG. 4, for the sake of convenience of explanation, four heat pipes 32 are provided on the outer surface of one plate-like body 11 and the outer surface of the other plate-like body 12, respectively. The plurality of heat pipes 32, 32, 32... are arranged in parallel along the heat transfer direction H of the heat transfer member 10. From the above, the notch parts 22 are provided at the central part and both ends of the base part of the heat radiation fins 21. Therefore, the heat radiation fins 21 are in contact with the heat pipes 32 at the central part and both ends of the base part of the heat radiation fins 21.

[0059] In addition, also in the heat sink 2, the shape of the heat pipe 32 in the longitudinal direction is linear, and the heat pipe 32 as the heat transfer medium 30 extends linearly from one end to the other end in the width direction of the heat radiation part 42. One end of the heat pipe 32 is located at one end in the width direction of the heat radiation part 42, and the other end of the heat pipe 32 is located at the other end in the width direction of the heat radiation part 42.

[0060] According to the aspect of the heat sink 2, since the heat transfer medium 30 is provided in the entire area of the connection part 31 between the heat transfer member 10 and the heat radiation fins 21 (heat radiation fin group 20), when the environmental temperature of the heat sink 2 is lower than the melting point of the working fluid of the heat transfer member 10, the function of the heat transfer medium 30 as a heat insulating material is further improved. Therefore, when the environmental temperature of the heat sink 2 is lower than the melting point of the working fluid of the heat transfer member 10, the effect of suppressing heat transfer from the heat radiation part 42 of the heat transfer member 10 to the heat radiation fins 21 (heat radiation fin group 20) is further improved, and it is possible to more reliably prevent the liquid-phase working fluid of the heat transfer member 10 from freezing at the heat radiation part 42 of the heat transfer member 10.

[0061] Next, the heat sink according to the third embodiment of the present invention will be described in detail. Since the heat sink according to the third embodiment has the same main components as the heat sinks according to the first and second embodiments, the same reference numerals will be used to describe the same components as those in the heat sinks according to the first and second embodiments. FIG. 5 is a side cross-sectional view for explaining the outline of the heat sink according to the third embodiment of the present invention. FIG. 6 is an exploded perspective view for explaining the structure of the heat transfer body and the heat radiation fin group of the heat sink according to the third embodiment of the present invention.

[0062] In the heat sinks 1 and 2 according to the first and second embodiments, the longitudinal shape of the heat pipe 32, which is the heat transfer body 30, was linear. However, as shown in FIGS. 5 and 6, in the heat sink 3 according to the third embodiment, one end 33 of the heat pipe 32 is located at the connection part 31, and the other end 34 of the heat pipe 32 is located on the tip of the heat radiation fin 21. The heat pipe 32, which is the heat transfer body 30, has a bent portion 35 at the central portion in its longitudinal direction, and both end portions (one end 33 and the other end 34) in its longitudinal direction are linear. In the heat sink 3, the heat pipe 32 has a U shape.

[0063] The heat pipe 32, which is the heat transfer body 30, has a bent portion 35 at the central portion in the longitudinal direction (elongation direction) of the heat pipe 32. One linear end 33 of the heat pipe 32 is located at the connection part 31 and is thermally connected to the base of the heat radiation fin 21 and the heat transfer member 10, and the other linear end 34 of the heat pipe 32 is thermally connected to the tip of the heat radiation fin 21. One end 33 and the other end 34 of the heat pipe 32 extend along the arrangement direction of the plurality of heat radiation fins 21, 21, 21 ··· and are thermally connected to the heat radiation fin group 20 over the entire longitudinal direction of the heat radiation fin group 20.

[0064] In the heat sink 3, when the ambient temperature of the heat sink 3 is normal temperature, not only heat is transferred from the heat radiating portion 42 of the heat transfer member 10 to the base of the heat radiating fins 21 (heat radiating fin group 20), but also heat is transferred from the heat radiating portion 42 of the heat transfer member 10 to the tips of the heat radiating fins 21 (heat radiating fin group 20) due to the heat transfer characteristics of the heat pipe 32 which is the heat transfer body 30. In the heat sink 3, since heat is also transferred from the heat radiating portion 42 of the heat transfer member 10 to the tips of the heat radiating fins 21 (heat radiating fin group 20), the fin efficiency of the heat radiating fins 21 (heat radiating fin group 20) is improved, and the cooling performance of the heat sink 3 is further improved.

[0065] Next, the heat sink according to the fourth embodiment of the present invention will be described in detail. Since the heat sinks according to the first to third embodiments and the heat sink according to the fourth embodiment have common main components, the same components as those of the heat sinks according to the first to third embodiments will be described using the same reference numerals. FIG. 7 is a perspective view for explaining the outline of the heat sink according to the fourth embodiment of the present invention.

[0066] In the heat sinks 1, 2, and 3 according to the first to third embodiments, the heat transfer member 10 is a vapor chamber in which the shape of the container 19 is planar and the entire internal space of the container 19 is integrated. However, as shown in FIG. 7, in the heat sink 4 according to the fourth embodiment, the heat transfer member 10 is a heat pipe group 60 in which a plurality of heat pipes 61, 61, 61... are arranged in parallel. Further, in the heat sinks 1, 2, and 3 according to the first to third embodiments, the heat transfer body 30 is a plurality of heat pipes 32, 32, 32... However, as shown in FIG. 7, in the heat sink 4 according to the fourth embodiment, the heat transfer body 30 is a vapor chamber 62 in which the shape of the container is planar and the entire internal space of the container is integrated. One vapor chamber 62 is provided.

[0067] As shown in FIG. 7, in the heat sink 4, since the heat transport member 10 has a configuration of a heat pipe group 60 in which a plurality of heat pipes 61, 61, 61... are arranged in parallel, the internal space as the heat transport member 10 is configured to be divided into a plurality of parts. The heat pipe 61 is a tubular body having a radial direction and a longitudinal direction. The heat pipe 61 is a member having an internal space in which a working fluid is enclosed, and the internal space of the heat pipe 61 is depressurized by a degassing process. From the above internal structure, the heat pipe 61 is a member having a heat transport function.

[0068] In the heat receiving portion 41 and the heat insulating portion 43 of the heat pipe group 60 which is the heat transport member 10, a plurality of heat pipes 61, 61, 61... are arranged in parallel along the radial direction of the heat pipe 61. On the other hand, corresponding to the fact that the heat radiating portion 42 of the heat transport member 10 is wider than the heat receiving portion 41 and the heat insulating portion 43, in the heat radiating portion 42 of the heat pipe group 60 which is the heat transport member 10, the heat pipe 61 is bent in an L shape. The heat pipe 61 located on the left side of the heat pipe group 60 is bent leftward at the heat radiating portion 42 and the heat radiating portion 42 extends leftward. The heat pipe 61 located on the right side of the heat pipe group 60 is bent rightward at the heat radiating portion 42 and the heat radiating portion 42 extends rightward.

[0069] As shown in FIG. 7, in the heat sink 4, a vapor chamber 62 which is a heat transport body 30 is provided at the connection portion between the heat pipe group 60 and the heat radiating fins 21 (heat radiating fin group 20). That is, the vapor chamber 62 is interposed between the heat pipe group 60 and the heat radiating fins 21 (heat radiating fin group 20). The shape of the vapor chamber 62 is plate-like. The vapor chamber 62 extends in a planar shape over substantially the entire heat radiating fin group 20 between the heat pipe group 60 and the heat radiating fin group 20.

[0070] Further, the vapor chamber 62 is a member having an internal space filled with a working fluid. The internal space of the vapor chamber 62 is depressurized by a degassing process. From the above internal structure, the vapor chamber 62 is also a member having a heat transport function. Further, the vapor chamber 62 is a separate member from the heat pipe group 60 which is the heat transport member 10, and the internal space of the vapor chamber 62 does not communicate with the internal space of the heat pipe group 60.

[0071] In the heat sink 4, a vapor chamber 62 extending in a planar shape is separately provided at a connection portion between the heat pipe group 60 and the heat radiation fins 21 (heat radiation fin group 20). When the ambient temperature of the heat sink 4 is lower than the melting point of the working fluid, the working fluid in the vapor chamber 62 freezes. Therefore, the vapor chamber 62 in which the working fluid has frozen functions as a heat insulating material, and as a result, heat transfer from the heat radiation portion 42 of the heat pipe group 60 to the heat radiation fins 21 (heat radiation fin group 20) is suppressed. When the ambient temperature of the heat sink 4 is lower than the melting point of the working fluid of the heat pipe group 60, heat transfer from the heat radiation portion 42 of the heat pipe group 60 to the heat radiation fins 21 (heat radiation fin group 20) is suppressed by the vapor chamber 62, thereby preventing the working fluid in the liquid phase of the heat pipe group 60 from freezing and undergoing a phase change to a solid-phase working fluid at the heat radiation portion 42 of the heat pipe group 60. Thus, even when the ambient temperature of the heat sink 4 is lower than the melting point of the working fluid of the heat pipe group 60, freezing of the working fluid in the liquid phase of the heat pipe group 60 is prevented, so that the working fluid of the heat pipe group 60 can reflux from the heat radiation portion 42 of the heat pipe group 60 to the heat receiving portion 41, preventing dry-out of the heat pipe group 60. Further, in the heat sink 4, when the ambient temperature of the heat sink 4 is lower than the melting point of the working fluid of the heat pipe group 60, the vapor chamber 62 extending in a planar shape functions as a heat insulating material, so that freezing of the working fluid of the heat pipe group 60 is suppressed. Thus, even when the ambient temperature of the heat sink 4 is lower than the melting point of the working fluid of the heat pipe group 60, since freezing of the working fluid of the heat pipe group 60 is suppressed, the time required for starting up the heat pipe group 60 can be shortened.

[0072] Also, in the aspect of the heat sink 4, when the environmental temperature of the heat sink 4 is higher than the melting point of the working fluid of the heat pipe group 60 (for example, normal temperature), since the working fluid in the vapor chamber 62 is not frozen, heat transfer from the heat dissipation part 42 of the heat pipe group 60 to the heat dissipation fins 21 (heat dissipation fin group 20) via the vapor chamber 62 is smoothed. Further, due to the heat transfer characteristics of the vapor chamber 62, the heat dissipation part 42 of the heat pipe group 60 is made isothermal throughout, so that the fin efficiency of the heat dissipation fins 21 (heat dissipation fin group 20) is improved, and the heat sink 4 exhibits excellent cooling performance.

[0073] From the above, also in the heat sink 4, without impairing the heat transfer characteristics of the heat transfer member 10, even when the environmental temperature of the heat sink 4 is lower than the melting point of the working fluid of the heat transfer member 10, dry-out of the heat transfer member 10 can be prevented, and the heat transfer member 10 can be smoothly started. Further, in the heat sink 4, since the heat transfer member 10 is a heat pipe group 60 in which a plurality of heat pipes 61, 61, 61 ··· are arranged in parallel, the heat transfer characteristics as the heat transfer member 10 are further surely improved.

[0074] Next, another embodiment of the present invention will be described. In the heat sinks of the above-described respective embodiments, heat dissipation fins were erected on both sides of the container, but an aspect in which heat dissipation fins are erected only on one surface of the container may also be used. Further, in the heat sinks of the above-described first to third embodiments, the heat transfer body was a plurality of heat pipes which are tubular bodies, but instead of this, one vapor chamber which is planar may be provided. Further, in the heat sink of the above-described fourth embodiment, one vapor chamber which is planar was provided as the heat transfer body, but instead of this, a plurality of heat pipes which are tubular bodies may be provided.

Industrial Applicability

[0075] The heat sink of the present invention can prevent dry-out even when the operating environment temperature is lower than the melting point of the working fluid. Therefore, it has high utility value especially in the field of cooling heat-generating bodies such as electronic components installed in a low-temperature environment.

Explanation of Reference Numerals

[0076] 1, 2, 3, 4 Heat sink 10 Heat transport member 20 Heat radiation fin group 21 Heat radiation fin 30 Heat transporter 31 Connection part 41 Heat receiving part 42 Heat radiation part 43 Heat insulation part

Claims

1. A heat transport member having a heat receiving portion thermally connected to a heating element, and a heat sink group in which a plurality of heat radiating fins are arranged and which is thermally connected to the heat radiating portion of the heat transport member, wherein the heat transport member has an internal space that communicates from the heat receiving portion to the heat radiating portion and in which a working fluid is enclosed, a heat transport body having an internal space in which a working fluid is enclosed is provided at a connection portion between the heat transport member and the heat radiating fins, the heat transport body is interposed between the heat transport member and the heat radiating fins, the heat transport body is in contact with the heat transport member and the heat radiating fins, the heat transport body is a heat pipe or a vapor chamber, when a heat transport body having an internal space in which a working fluid is enclosed is separately provided at the connection portion, when the environmental temperature is lower than the melting point of the working fluid, the working fluid of the heat transport body freezes, and the heat transport body in which the working fluid has frozen functions as a heat insulating material Heat sink.

2. The heat sink according to claim 1, wherein the heat transport body is provided over the entire area of the connection portion.

3. The heat sink according to claim 1 or 2, wherein the heat transport body has a bent portion at a central portion in the extending direction of the heat transport body, one end of the heat transport body is located at the connection portion, and the other end of the heat transport body is thermally connected to the tip of the heat radiating fin.

4. The heat sink according to any one of claims 1 to 3, wherein the heat transport body is not provided at the heat receiving portion and the heat insulating portion of the heat transport member located between the heat receiving portion and the heat radiating portion.

5. The heat sink according to any one of claims 1 to 4, wherein the internal space of the heat transport member is integral.

6. The heat sink according to any one of claims 1 to 4, wherein the heat transport member is a heat pipe group in which a plurality of heat pipes are arranged in parallel.

7. The heat sink according to any one of claims 1 to 6, wherein the heat radiating portion of the heat transport member is wider than the heat receiving portion.

Images