JP2020053570A - Heat dissipation structure - Google Patents

Abstract

To provide a heat dissipation structure capable of efficiently dissipating heat from a heat generating portion inside a housing of an electronic device or the like.SOLUTION: A heat dissipation structure 1 includes: a heat generating unit 2 provided inside a housing; an internal heat dissipation unit 3, provided inside the housing, receiving heat from the heat generating unit; an external heat dissipation unit 7, provided outside the housing, having a plurality of fins 7a having a main surface including a long side and a short side arranged side by side; a heat pipe 5 for transmitting heat from the internal heat dissipation unit to the external heat dissipation unit; and a blower 6 for blowing air to the fins in a direction along the short side of the fins.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat dissipation structure.

  2. Description of the Related Art A heat dissipating structure that dissipates heat from a heat generating portion inside a housing of an electronic device or the like is known. Patent Literature 1 discloses a heat radiating structure in which a heat generating portion arranged inside a housing, an air passage arranged outside the housing to allow air to flow by a motor fan, and a heat connecting the heat generating portion and the air passage. And a fin in a portion of the heat member located in the air passage.

JP 2008-165699 A

  The configuration diagram of the heat dissipation structure in Patent Document 1 shows a configuration in which the fin has a long side and a short side and a motor fan is arranged so that air flows in a direction along the long side of the fin. However, in such a configuration, there is a case where the heat generating portion disposed inside the housing cannot be efficiently dissipated.

  An object of the present disclosure is to provide a heat radiating structure that can efficiently radiate a heat generating portion inside a housing of an electronic device or the like in view of the above-described problem.

  A heat radiating structure according to a first aspect of the present invention includes: a heat generating portion provided inside a housing; an internal heat radiating portion provided inside the housing and receiving heat from the heat generating portion; An external heat dissipating part provided outside the fin and having a plurality of fins having a main surface composed of a long side and a short side arranged side by side, a heat pipe for transmitting heat from the internal heat dissipating part to the external heat dissipating part, And a blower for blowing air to the fin in a direction along the short side of the fin.

  According to the present invention, it is possible to efficiently radiate heat from a heat generating portion inside a housing of an electronic device or the like.

It is a figure explaining the outline of the present invention. FIG. 2 is a schematic diagram illustrating a structure of a heat dissipation structure according to the first embodiment. FIG. 2 is a schematic diagram illustrating a structure of a heat dissipation structure according to the first embodiment. FIG. 4 is a perspective view showing a positional relationship of a heat pipe with respect to an internal heat radiating portion and an external heat radiating portion in the heat radiating structure according to the first exemplary embodiment; FIG. 4 is a perspective view showing a positional relationship of a heat pipe with respect to an internal heat radiating portion and an external heat radiating portion in the heat radiating structure according to the first exemplary embodiment; FIG. 3 is a schematic diagram illustrating a mounting portion of a fixing member in a housing of the heat dissipation structure according to the first embodiment. FIG. 3 is a schematic diagram illustrating a configuration of a housing of the heat dissipation structure according to the first embodiment. FIG. 3 is a schematic diagram illustrating a configuration of an external heat radiating portion of the heat radiating structure according to the first embodiment. FIG. 4 is a schematic diagram showing an ideal shape of a heat radiation fin group in forced air cooling obtained by simulation. FIG. 9 is a schematic diagram showing a hatched area A in FIG. 8. It is a schematic diagram explaining the method of manufacturing a fin by a curling method in an external heat radiation part. It is a schematic diagram explaining the structure of the heat dissipation structure according to the second embodiment. It is a schematic diagram which shows the structure of the housing heat dissipation surface of the modification 1. It is a schematic diagram explaining arrangement | positioning of the heat pipe in the housing | casing heat radiation surface of the modification 1. FIG. 11 is a schematic diagram illustrating a configuration of a housing heat radiation surface according to a second modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description and drawings are appropriately omitted and simplified for clarity of explanation. In each of the drawings, the same elements are denoted by the same reference numerals, and repeated description will be omitted as necessary. Note that the right-handed XYZ coordinates shown in the figure are for convenience in describing the positional relationship of the components.

[Features of the present invention]
Prior to the description of the embodiments of the present invention, the features of the present invention will be outlined first. The present invention relates to a heat dissipation structure used for a housing of an electronic device or the like.

  FIG. 1 is a diagram illustrating an outline of the present invention. As shown in FIG. 1, the heat radiation structure 1 includes a heat generating part 2, an internal heat radiation part 3, an external heat radiation part 4, a heat pipe 5, and a blower 6.

  The heat generating section 2 is provided inside the housing 8. The internal heat radiating section 3 is provided inside the housing 8 and receives heat from the heat generating section 2. The external heat radiating portion 4 is provided outside the housing, and a plurality of fins 7a having a main surface including a long side and a short side are arranged side by side. The heat pipe 5 transmits heat from the internal heat radiating section 3 to the external heat radiating section 4. The blower 6 blows air to the fin 7a in a direction along the short side of the fin 7a. By doing so, the heat generating portion 2 inside the housing 8 can be efficiently dissipated.

[Embodiment 1]

Hereinafter, Embodiment 1 will be described.
The heat dissipating structure according to the first embodiment is used for, for example, an electronic device installed outdoors, for example, a wireless communication device such as an antenna.

  2 and 3 are schematic diagrams illustrating the structure of the heat radiation structure 101 according to the first embodiment. As shown in FIGS. 2 and 3, the heat radiation structure 101 includes a heat generating part 102, an internal heat radiation part 103, an external heat radiation part 107, a heat pipe 105, and a blower 106.

  The heat generating unit 102 is provided inside the housing 108. The heating unit 102 is, for example, an electronic board. The internal heat radiating section 103 is provided inside the housing 108 and receives heat from the heat generating section 102. The external heat radiating section 107 is provided outside the housing and has fins 107a. The heat pipe 105 transmits heat from the internal heat radiating section 103 to the external heat radiating section 107. The heat pipe 105 generally transports heat by a phase change (evaporation / condensation) of the working liquid sealed in a small amount in a pipe-shaped container. General heat pipes have very high thermal conductivity (5000-30000 W / mK), do not require external power to operate, have high heat responsiveness, and have no moving parts. There are features. The blower 106 blows air to the fins 107a. The external radiator 107 and the blower 106 are covered with a cover 109.

  4 and 5 are perspective views showing the positional relationship of the heat pipe 105 with respect to the internal heat radiating section 103 and the external heat radiating section 107 in the heat radiating structure 101. FIG. As shown in FIGS. 4 and 5, a plurality of heat pipes 105 are arranged side by side at predetermined intervals in a direction along the main surface 103 a of the internal heat radiating section 103. The internal heat dissipating section 103 and the heat pipe 105 are fixed by soldering, caulking, brazing, or the like. The heat pipe 105 is connected to the external heat radiating section 107 at an end opposite to the end connected to the internal heat radiating section 103. A fixing member 110 for fixing the heat radiation structure 101 to the housing 108 is provided between the internal heat radiation part 103 and the external heat radiation part 107 in the heat pipe 105. The fixing member 110 has a through hole 110a for penetrating the heat pipe 105 and a through hole 110b for screwing. The fixing of the fixing member 110 and the heat pipe 105 is performed by soldering, caulking, brazing, or the like. When the housing 108 is used for a wireless communication device such as an antenna, the housing 108 is installed outdoors exposed to rain and wind, so that waterproofness is required. The gap between the through hole 110a and the heat pipe 105 is filled with a waterproof member such as silicone.

  FIG. 6 is a schematic diagram illustrating a mounting portion of the housing 108 to which the fixing member 110 is attached. As shown in FIG. 6, the heat dissipation structure 101 is fixed to the housing 108 by inserting the heat dissipation structure 101 into the opening 112 formed in the housing 108 and fastening the housing 108 and the fixing member 110 with screws. can do. A packing portion 111 is provided at a peripheral portion of the opening 112 in the housing 108. As a result, the housing 108 and the fixing member 110 come into contact with each other via the packing 111. In this way, waterproofness and weather resistance can be ensured.

  FIG. 7 is a schematic diagram illustrating a configuration of the housing 108. As shown in FIG. 7, the housing 108 includes a cover 108a, a cover 108b, and a case 108c. The case portion 108c has a configuration in which a cavity is provided at the center. An arbitrary number of heat generating portions 102 that can be accommodated in the central cavity of the case portion 108c can be fixed to two surfaces of the internal heat radiating portion 103 where the cover portion 108a and the cover portion 108b face each other. After fixing the heat generating part 102 to the internal heat radiation part 103, the cover part 108a and the cover part 108b are fixed to the case part 108c. By providing a waterproof gasket at each of the contact portions of the cover portion 108a, the cover portion 108b, and the case portion 108c, waterproofness can be ensured. The case portion 108c and the heat dissipation structure 101 can be integrally processed. As a specific example, there is a method in which the heat pipe 105 is formed by being cast into the case portion 108c, or a method in which a through hole through which the heat pipe 105 passes is formed in the case portion 108c, and the gap is filled with a member such as silicone.

  Next, the configuration of the external heat radiating unit 107 will be described in detail. The present inventors have simulated that, for a forced air cooling type radiator having fins such as the external radiator 107, the flow of air in a direction along the short side of the main surface of the fins improves the heat radiation efficiency. Found by FIG. 8 is a schematic diagram showing the configuration of the external heat radiation unit 107. As shown in FIG. 8, the external heat radiating unit 107 includes a plurality of fins 107a having a main surface 107b including a long side 107bA and a short side 107bB, which are arranged in the X direction. The wind F1 from the blower 6 (see FIG. 3) flows in the direction along the short side 7bB of the fin 107a (that is, the Y direction).

  The heat pipes 105 are arranged in the fin 107a at a predetermined interval L1 in the center of the short side 107bB of the main surface 107b of the fin and in the direction along the long side 107bA of the main surface 107b of the fin 107a. . The predetermined interval L1 is set so that half the length of the predetermined interval L1 is shorter than the length L2 of the short side 107bB of the main surface 107b of the fin 107a (L1 / 2 <L2). Further, the length L2 of the short side 107bB of the main surface 107b of the fin 107a is set shorter than the length L3 between the fins located at one end and the other end in the direction in which the fins 107a are arranged.

  Increasing the number of the heat pipes 105 increases the heat transfer amount and improves the heat radiation performance. However, if the number of heat pipes 105 is excessively increased, the flow of the air in the gap between the adjacent fins 107a is obstructed, so that the heat radiation performance is reduced. Therefore, the number of heat pipes 105 is determined in consideration of the heat transport amount of the heat pipes 105 and the flow of wind between the fins 107a. Aluminum is generally selected as the material of the fin 107a, but copper may be selected. The fin 107a and the heat pipe 105 are fixed by soldering, caulking, brazing, or the like.

  FIG. 9 is a schematic diagram showing an ideal shape of the heat radiation fin group 907 in forced air cooling obtained by simulation. As shown in FIG. 9, the length Lx of the side 907bA of the main surface 907b, which is perpendicular to the air blowing direction, and the air blowing direction F It was found that the shorter the length Ly of the side 907bB along the line, the better the heat radiation efficiency (Lx> Ly, Lx> Lz). In addition, it was found that the shorter the length Lz of the side 907bA perpendicular to the air blowing direction than the length Ly of the side 907bB along the air blowing direction, the better the heat radiation efficiency (Ly> Lz). However, when the heat radiation fin group 907 has such a shape, heat radiation efficiency is good, but the number of fins 907a needs to be increased, and the length in the X direction becomes long.

  As shown in FIGS. 2 and 3, when the length of the external heat radiating portion 107 in the X direction increases, the length of the cover 109 covering the external heat radiating portion 107 and the blower 106 also needs to be increased. As the length of the cover 109 in the X direction increases, the size of the device increases accordingly. Therefore, when the present invention is applied to a wireless communication device having a limited device size, the length of the external radiator 107 in the X direction needs to be as short as possible. On the other hand, the dimensions of the cover 109 in the Z direction and the Y direction match the housing 108. Therefore, the dimensions of the external heat radiating portion 107 in the Z and Y directions need to be smaller than the dimensions of the cover 109 in the Z and Y directions. In the example of the wireless communication device illustrated in FIGS. 2 and 3, the length in the Z direction of the housing 108 is longer than the length in the Y direction. That is, in the external heat radiating portion 107, the length in the Z direction can be made somewhat longer than the length in the X direction and the Y direction.

  FIG. 10 is a schematic diagram showing a hatched area A in FIG. As shown in FIG. 10, the area A can be said to be an area allocated to radiate heat transmitted from a half portion of one heat pipe 105. The shape of the fin 107a in the region A is equivalent to the shape of the fin 907a shown in FIG. That is, in the region A, the length L4 (= L1 / 2) in the Z direction of the main surface 107a of the fin 107a is shorter than the length L2 in the Y direction (that is, the blowing direction F1).

  The length L3 between the fins located at one end and the other end in the direction in which the fins 107a are arranged in the external heat radiating unit 107 shown in FIG. 8 is equal to one end of the radiating fin group 907 shown in FIG. It can be shorter than the length Lx between the fins located at the other end. This is because in the external heat radiating unit 107 shown in FIG. 8, a plurality of heat pipes 105 are arranged at predetermined intervals in the Z direction, and the length of the fin 107a in the Z direction is set to the fin of the heat radiating fin group 907 shown in FIG. 907a is longer than the length in the Z direction. By doing so, it is possible to suppress the increase in the length in the x direction, which is strictly limited in space, while maintaining the heat radiation performance equal to that of the ideal heat radiation fin group 907 in forced air cooling. Thus, when the heat dissipation structure 101 according to the present embodiment is applied to a wireless communication device, an increase in device size can be suppressed.

  In the forced air cooling type radiator, the shorter the distance between adjacent fins, the larger the surface area and the better the heat radiation performance.However, when the distance between the fins is extremely narrow, the flow of wind Inhibits. For this reason, in the external heat radiating portion 107 shown in FIG. 8, the interval between the adjacent fins 107a is preferably set to about 0.5 mm or more. The fin 107a is generally manufactured by a method such as cutting, casting, or extrusion, but a gap of several mm is left in these methods. Therefore, when the distance between adjacent fins is reduced to about 0.5 mm, the fins may be formed by a curling method.

  FIG. 11 is a schematic diagram for explaining a method of manufacturing the fins 107a by the curling method in the external heat radiating unit 107. As shown in FIG. 11, in the curling method, the fins 107a provided with the bent portions 107d on at least one of the short sides 107bB are fitted one by one into the heat pipe 105 in the through holes 107c. The height h of the bent portion 107d in the direction in which the fins 107a are arranged is set to a desired fin interval (for example, 0.5 mm). With this configuration, when the fin 107a is fitted into the heat pipe 105 in the through hole 107c, the tip of the bent portion 107d of the fin 107a abuts on the adjacent fin 107a, and the fin interval does not approach the height h. Is regulated. Thereby, in the external heat radiating portion 107, the interval between the adjacent fins 107a can be set to a desired fin interval. In the fin 107a shown in FIG. 11, the bent portion 107d is formed by being bent substantially perpendicularly to the main surface 107b, but is not limited thereto. For example, the bent portion 107d may be bent at a predetermined curvature with respect to the main surface 107b. May be formed.

  Instead of using the curling method described above, when fitting the fins 107a one by one into the heat pipe 105 in the through holes 107c, the spacers may be inserted into the gaps between the adjacent fins 107a. The height of the spacer in the direction in which the fins 107a are arranged is set to a desired fin interval. In this manner, similarly to the case of the curling method, the spacer is regulated by the spacer so that the fin interval does not approach the height h.

[Embodiment 2]
Hereinafter, Embodiment 2 will be described.
FIG. 12 is a schematic diagram illustrating the structure of the heat dissipation structure 201 according to the second embodiment. The difference from the heat dissipation structure 101 according to the first embodiment (see FIG. 3) is that a heat dissipation portion is provided in a part of the housing. As shown in FIG. 12, the heat dissipation structure 201 further includes a housing heat dissipation surface 208d provided at a predetermined portion of a wall surface forming the housing 208. The housing heat radiating surface 208d faces the heat generating portion 202. There is no obstacle between the housing heat radiation surface 208d and the heat generating part 202. By doing so, the heat radiation performance can be further improved.

[Modification 1]
FIG. 13 is a schematic diagram illustrating a configuration of a modification of the heat dissipation surface of the housing. As shown in FIG. 13, in the heat radiation structure 301, the heat pipe 305 may be connected to the heat radiation surface 308 d of the housing provided at a predetermined portion of the wall surface forming the housing 308. The heat pipe 305 generally transports heat by a phase change of evaporation and condensation of the working liquid sealed in a small amount in a pipe-shaped container. FIG. 14 is a schematic diagram illustrating the arrangement of the heat pipe 305 on the housing heat radiation surface 308d. As shown in FIG. 14, a part of the heat pipe 305 may be embedded in the housing heat dissipation surface 308d. By doing so, the heat radiation performance can be further improved.

[Modification 2]
FIG. 15 is a schematic diagram illustrating a configuration of another modified example of the heat dissipation surface of the housing. As shown in FIG. 15, in the heat dissipation structure 401, when the case 408 has a cylindrical shape, the cover of the case 408 may be a case heat dissipation surface 408d. By doing so, the heat radiation performance can be further improved.

  It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist. Further, the plurality of examples described above can be implemented in combination as appropriate.

1, 101, 201, 301, 401 Heat radiating structure 2, 102, 202 Heat generating part 3, 103 Internal heat radiating part 5, 105, 305 Heat pipe 6, 106 Blower 7, 107 External heat radiating part 7a, 107a Fin 8, 108, 208, 308, 408 Case 208d, 308d, 408d Case heat radiation surface

Claims (6)

A heating section provided inside the housing;
An internal heat radiating unit provided inside the housing and receiving heat from the heat generating unit;
An external heat radiator provided outside the housing and having a plurality of fins having a main surface composed of a long side and a short side arranged side by side,
A heat pipe that transmits heat from the internal heat radiating section to the external heat radiating section,
And a blower for blowing air to the fin in a direction along a short side of the fin.   A plurality of the heat pipes are provided, and the heat pipes are arranged at predetermined centers in the fin at a center of a short side of the main surface of the fin and in a direction along a long side of the main surface of the fin. The heat dissipation structure according to claim 1, wherein The predetermined interval is set so that half the length of the predetermined interval is shorter than the length of the short side of the main surface of the fin,
The heat dissipation structure according to claim 2, wherein a length of a short side of the main surface of the fin is set shorter than a length between fins located at one end and the other end in the direction in which the fins are arranged.   The apparatus further includes a housing heat radiation surface provided at a predetermined portion of a wall surface forming the housing, wherein the housing heat radiation surface faces the heat generating portion, and is located between the housing heat radiation surface and the heat generating portion. The heat dissipation structure according to any one of claims 1 to 3, wherein no obstacle is present in the heat dissipation structure.   The heat dissipation structure according to claim 4, wherein a part of the heat pipe is embedded inside the housing heat dissipation surface.   The heat dissipation structure according to any one of claims 1 to 5, wherein the housing is a housing for a wireless communication device installed outdoors.