Heat dissipation structure

Abstract

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

Description

Technical Field

[0001] The present invention relates to a heat dissipation structure.

Background Art

[0002] A heat dissipation structure for dissipating heat from a heat generating part inside a housing of an electronic device or the like is known. In Patent Document 1, a heat dissipation structure includes a heat generating part disposed inside a housing, an air passage disposed outside the housing through which air is flowed by a motor fan, and a heat member connecting the heat generating part and the air passage, and a configuration having fins at a portion of the heat member located in the air passage is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration diagram of the heat dissipation structure in Patent Document 1, the fins have a shape having a long side and a short side, and a configuration in which a motor fan is arranged so that air flows in a direction along the long side of the fins is shown. However, with such a configuration, there are cases where the heat generating part disposed inside the housing cannot be efficiently dissipated.

[0005] An object of the present disclosure is to provide a heat dissipation structure capable of efficiently dissipating heat from a heat generating part inside a housing of an electronic device or the like in view of the above-described problems.

Means for Solving the Problems

[0006] The heat dissipation structure according to the first aspect of the present invention includes a heat generating part provided inside a housing, an internal heat dissipation part provided inside the housing and receiving heat from the heat generating part, an external heat dissipation part provided outside the housing and having a plurality of fins arranged side by side with a main surface composed of a long side and a short side, a heat pipe for transmitting heat from the internal heat dissipation part to the external heat dissipation part, and a blower for blowing air in a direction along the short side of the fins with respect to the fins.

Effects of the Invention

[0007] According to the present invention, the heat generating part inside the housing of an electronic device or the like can be efficiently dissipated.

Brief Description of the Drawings

[0008]

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[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. For the sake of clarity of explanation, the following description and drawings are appropriately omitted and simplified. In each drawing, the same reference numerals are assigned to the same elements, and duplicate explanations are omitted as necessary. Note that the right-handed XYZ coordinates shown in the figures are for convenience in explaining the positional relationship of the components.

[0010] [Features of the Present Invention] Prior to the description of the embodiments of the present invention, an overview of the features of the present invention will be first described. The present invention relates to a heat radiating structure used for a housing of an electronic device or the like.

[0011] FIG. 1 is a diagram for explaining the overview of the present invention. As shown in FIG. 1, the heat radiating structure 1 includes a heat generating part 2, an internal heat radiating part 3, an external heat radiating part 4, a heat pipe 5, and a blower 6.

[0012] The heat generating part 2 is provided inside the housing 8. The internal heat radiating part 3 is provided inside the housing 8 and receives heat from the heat generating part 2. The external heat radiating part 4 is provided outside the housing, and a plurality of fins 7a having a main surface composed of a long side and a short side are arranged side by side. The heat pipe 5 transmits heat from the internal heat radiating part 3 to the external heat radiating part 4. The blower 6 blows air in a direction along the short side of the fins 7a with respect to the fins 7a. By doing so, the heat generating part 2 inside the housing 8 can be efficiently cooled.

[0013] [Embodiment 1]

[0014] Hereinafter, Embodiment 1 will be described. The heat dissipation structure according to Embodiment 1 is used, for example, in an electronic device installed outdoors, such as a wireless communication device such as an antenna.

[0015] FIG. 2 and FIG. 3 are schematic diagrams for explaining the structure of the heat dissipation structure 101 according to Embodiment 1. As shown in FIGS. 2 and 3, the heat dissipation structure 101 includes a heat generating part 102, an internal heat radiating part 103, an external heat radiating part 107, a heat pipe 105, and a blower 106.

[0016] The heat generating part 102 is provided inside the housing 108. The heat generating part 102 is, for example, an electronic substrate. The internal heat radiating part 103 is provided inside the housing 108 and receives heat from the heat generating part 102. The external heat radiating part 107 is provided outside the housing and has fins 107a. The heat pipe 105 transmits heat from the internal heat radiating part 103 to the external heat radiating part 107. The heat pipe 105 is a general one that transports heat by the phase change (evaporation / condensation) of a small amount of working liquid enclosed in a pipe-shaped container. General heat pipes have characteristics such as a very high thermal conductivity (5000 - 30000 W / m·K), no need for external power to operate, high thermal responsiveness, and no moving parts. The blower 106 blows air against the fins 107a. The external heat radiating part 107 and the blower 106 are covered with a cover 109.

[0017] Figures 4 and 5 are perspective views showing the positional relationship of the heat pipe 105 with respect to the internal heat dissipation part 103 and the external heat dissipation part 107 in the heat dissipation structure 101. As shown in Figures 4 and 5, the heat pipes 105 are installed side by side at a plurality of predetermined intervals in the direction along the main surface 103a of the internal heat dissipation part 103. The internal heat dissipation part 103 and the heat pipe 105 are fixed by soldering, caulking, brazing, etc. The heat pipe 105 is connected to the external heat dissipation part 107 at the end opposite to the end connected to the internal heat dissipation part 103. Between the internal heat dissipation part 103 and the external heat dissipation part 107 in the heat pipe 105, a fixing member 110 for fixing the heat dissipation structure 101 to the housing 108 is installed. The fixing member 110 is formed with a through hole 110a for passing the heat pipe 105 therethrough and a through hole 110b for screwing. The fixing member 110 and the heat pipe 105 are fixed by soldering, caulking, brazing, etc. When the housing 108 is for a wireless communication device such as an antenna, the housing 108 is installed outdoors exposed to rain and wind, so waterproofness is required. The gap between the through hole 110a and the heat pipe 105 is filled with a waterproof member such as silicone.

[0018] Figure 6 is a schematic diagram showing the attachment part of the fixing member 110 in the housing 108. As shown in Figure 6, 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, the heat dissipation structure 101 can be fixed to the housing 108. A packing part 111 is provided at the peripheral part of the opening 112 in the housing 108. Thereby, the housing 108 and the fixing member 110 are in contact with each other via the packing part 111. By doing so, waterproofness and weather resistance can be ensured.

[0019] FIG. 7 is a schematic diagram showing the configuration of the housing 108. As shown in FIG. 7, the housing 108 is composed of a cover part 108a, a cover part 108b, and a case part 108c. The case part 108c has a configuration with a cavity in the center. On the two opposing surfaces of the internal heat dissipation part 103 where the cover part 108a and the cover part 108b face each other, any number of heat generating parts 102 that can be accommodated in the central cavity of the case part 108c can be fixed. After fixing the heat generating part 102 to the internal heat dissipation part 103, the cover part 108a and the cover part 108b are fixed to the case part 108c. Waterproofness can also be ensured by providing a waterproof gasket at each contact part of the cover part 108a, the cover part 108b, and the case part 108c. The case part 108c and the heat dissipation structure 101 can also be integrally processed. As a specific example, there are a method of forming the heat pipe 105 by casting it into the case part 108c, and a method of forming a through hole through which the heat pipe 105 passes in the case part 108c and filling the gap with a member such as silicone.

[0020] Next, the details of the configuration of the external heat dissipation part 107 will be described. The inventors have found through simulation that for a radiator of the forced air cooling type having fins such as the external heat dissipation part 107, the heat dissipation efficiency improves when the air flows in the direction along the short side on the main surface of the fins. FIG. 8 is a schematic diagram showing the configuration of the external heat dissipation part 107. As shown in FIG. 8, the external heat dissipation part 107 has a plurality of fins 107a arranged side by side in the X direction, each having a main surface 107b composed of a long side 107bA and a short side 107bB. The air F1 from the blower 6 (see FIG. 3) flows in the direction along the short side 7bB of the fin 107a (i.e., the Y direction).

[0021] Further, in the fins 107a, the heat pipes 105 are arranged side by side at a predetermined interval L1 at the center of the short side 107bB of the main surface 107b of the fins and along the long side 107bA of the main surface 107b of the fins 107a. The predetermined interval L1 is set such that half of 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 fins 107a (L1 / 2 < L2). Also, the length L2 of the short side 107bB of the main surface 107b of the fins 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.

[0022] Increasing the number of heat pipes 105 improves the heat transport amount and enhances the heat dissipation performance. However, if the number is increased too much, the flow of air in the gaps between adjacent fins 107a is obstructed, resulting in a decrease in the heat dissipation performance instead. Therefore, the number of heat pipes 105 is determined considering the heat transport amount of the heat pipes 105 and the air flow between the fins 107a. Generally, aluminum is selected as the material for the fins 107a, but copper may also be selected. The fins 107a and the heat pipes 105 are fixed by soldering, caulking, brazing, etc.

[0023] FIG. 9 is a schematic diagram showing the shape of an ideal heat dissipation fin group 907 in forced air cooling obtained by simulation. As shown in FIG. 9, it was found that the heat dissipation efficiency is better when the length Lz of the side 907bA perpendicular to the air blowing direction and the length Ly of the side 907bB along the air blowing direction F on the main surface 907b are shorter with respect to the length Lx between the fins located at one end and the other end in the direction in which the fins 907a are arranged (Lx > Ly, Lx > Lz). Also, it was found that the heat dissipation efficiency is better when the length Lz of the side 907bA perpendicular to the air blowing direction is shorter than the length Ly of the side 907bB along the air blowing direction (Ly > Lz). However, if the heat dissipation fin group 907 has such a shape, although the heat dissipation efficiency is good, it is necessary to increase the number of fins 907a, and the length in the X direction becomes longer.

[0024] As shown in FIGS. 2 and 3, when the length of the external heat radiation part 107 in the X direction becomes longer, it is necessary to also increase the length of the cover 109 that covers the external heat radiation part 107 and the blower 106 in the X direction. When the length of the cover 109 in the X direction becomes longer, the size of the device increases accordingly. Therefore, when applying it to a wireless communication device with a constraint on the device size, it is necessary to make the length of the external radiator 107 in the X direction as short as possible. On the other hand, the dimensions of the cover 109 in the Z and Y directions are made to match those of the housing 108. Therefore, the dimensions of the external heat radiation part 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 shown in FIGS. 2 and 3, the length of the housing 108 in the Z direction is longer than the length in the Y direction. That is, in the external heat radiation part 107, the length in the Z direction can be made relatively long compared to the lengths in the X and Y directions.

[0025] FIG. 10 is a schematic diagram showing the hatched area A in FIG. 8. As shown in FIG. 10, the area A can be said to be an area assigned to dissipate the heat transmitted from half of one heat pipe 105. The shape of the fins 107a in the area A is equivalent to the shape of the fins 907a shown in FIG. 9. That is, in the area A, the length L4 (= L1 / 2) in the Z direction on the main surface 107a of the fins 107a is shorter than the length L2 in the Y direction (i.e., the air blowing direction F1).

[0026] In the external heat dissipation part 107 shown in FIG. 8, the length L3 between the fins located at one end and the other end in the direction in which the fins 107a are arranged can be made shorter than the length Lx between the fins located at one end and the other end in the direction in which the fins 907a are arranged in the heat dissipation fin group 907 shown in FIG. 9. This is because in the external heat dissipation part 107 shown in FIG. 8, a plurality of heat pipes 105 are arranged side by side at a predetermined interval in the Z direction, and the length of the fins 107a in the Z direction is made longer than the length of the fins 907a in the Z direction of the heat dissipation fin group 907 shown in FIG. 9. By doing so, it is possible to suppress an increase in the length in the x direction, which is severely restricted in terms of space, while maintaining the heat dissipation performance equivalent to that of the ideal heat dissipation fin group 907 in forced air cooling. As a result, when the heat dissipation structure 101 according to the present embodiment is applied to a wireless communication device, an increase in the device size can be suppressed.

[0027] Further, in a radiator using the forced air cooling method, the smaller the interval between adjacent fins, the larger the surface area and the tendency for the heat dissipation performance to improve. However, if the interval between the fins is extremely narrowed, the flow of air is conversely obstructed. For this reason, in the external heat dissipation part 107 shown in FIG. 8, the interval between adjacent fins 107a is preferably about 0.5 mm or more. The fins 107a are generally manufactured by methods such as cutting, casting, and extrusion, but gaps of several millimeters are formed in these methods. Therefore, when the interval between adjacent fins is narrowed to about 0.5 mm, it may be formed by a curling method.

[0028] FIG. 11 is a schematic diagram for explaining a method of manufacturing the fins 107a by a curling method in the external heat radiation part 107. As shown in FIG. 11, in the curling method, the fins 107a each provided with a bent portion 107d on at least one of the short sides 107bB are fitted one by one into the heat pipe 105 at 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). In this way, when the fins 107a are fitted into the heat pipe 105 at the through holes 107c, the tip of the bent portion 107d of the fin 107a abuts on the adjacent fin 107a, and the fin interval is regulated so as not to approach the height h. Thereby, in the external heat radiation part 107, the interval between 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 perpendicular to the main surface 107b, but the present invention is not limited thereto, and for example, it may be formed by being bent with a predetermined curvature with respect to the main surface 107b.

[0029] Instead of using the curling method described above, when fitting the fins 107a one by one into the heat pipe 105 at the through holes 107c, spacers may be inserted into the gaps between 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 way, similarly to the case of the curling method, the fin interval is regulated by the spacer so as not to approach the height h.

[0030] [Embodiment 2] Hereinafter, Embodiment 2 will be described. FIG. 12 is a schematic diagram for explaining the structure of the heat dissipation structure 201 according to Embodiment 2. The difference from the heat dissipation structure 101 (see FIG. 3) according to Embodiment 1 is that a heat dissipation part 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 the wall surface constituting the housing 208. The housing heat dissipation surface 208d faces the heat generating part 202. There is no obstacle between the housing heat dissipation surface 208d and the heat generating part 202. By doing so, the heat dissipation performance can be further improved.

[0031] [Modification Example 1] FIG. 13 is a schematic diagram showing the configuration of a modification example of the housing heat dissipation surface. As shown in FIG. 13, in the heat dissipation structure 301, the housing heat dissipation surface 308d provided at a predetermined portion of the wall surface constituting the housing 308 and the heat pipe 305 may be connected. The heat pipe 305 is a general one that transports heat by the phase change of evaporation and condensation of a small amount of working liquid enclosed in a pipe-shaped container. FIG. 14 is a schematic diagram for explaining the arrangement of the heat pipe 305 on the housing heat dissipation surface 308d. As shown in FIG. 14, a part of the heat pipe 305 may be embedded inside the housing heat dissipation surface 308d. By doing so, the heat dissipation performance can be further improved.

[0032] [Modification Example 2] FIG. 15 is a schematic diagram showing the configuration of another modification example of the housing heat dissipation surface. As shown in FIG. 15, in the heat dissipation structure 401, when the housing 408 has a cylindrical shape, the lid of the housing 408 may be used as the housing heat dissipation surface 408d. By doing so, the heat dissipation performance can be further improved.

[0033] Note that the present invention is not limited to the above-described embodiments, and can be appropriately modified without departing from the gist. In addition, the plurality of examples described above can also be implemented in appropriate combinations.

Explanation of Reference Numerals

[0034] 1, 101, 201, 301, 401 Heat dissipation structure 2, 102, 202 Heating parts 3, 103 Internal heat dissipation parts 5, 105, 305 Heat pipes 6, 106 Blowers 7, 107 External heat dissipation parts 7a, 107a Fins 8, 108, 208, 308, 408 Housings 208d, 308d, 408d Housing heat dissipation surfaces

Claims

1. A heat generating part provided inside the housing, An internal heat radiating part provided inside the housing and receiving heat from the heat generating part, An external heat radiating part provided outside the housing, in which a plurality of fins having a main surface composed of a long side and a short side are arranged side by side, A heat pipe for transmitting heat from the internal heat radiating part to the external heat radiating part, A blower for blowing air in a direction along the short side of the fin with respect to the fin, Comprising: The heat pipe is fixed to the internal heat radiating part, Further comprising a housing heat radiating surface provided at a predetermined part of the wall surface constituting the housing, the housing heat radiating surface facing the heat generating part, A heat radiating structure in which a part of the heat pipe is embedded inside the housing heat radiating surface.

2. Comprising a fixing member fixed to the peripheral part of an opening formed in one surface of the housing, The heat radiating structure according to claim 1, wherein the heat pipe penetrates through the fixing member.

3. The heat generating part and the internal heat radiating part are plate-shaped, one or more heat generating parts are provided, and the heat generating part is in contact with one side or both sides of the internal heat radiating part. The heat radiating structure according to any one of claims 1 or 2.

4. Comprising a plurality of the heat pipes, and the heat pipes are fixed to the internal heat radiating part at a predetermined interval. The heat radiating structure according to any one of claims 1 to 3.

5. Comprising a plurality of the heat pipes, and the heat pipes are arranged side by side at a predetermined interval in a direction along the long side of the main surface of the fin at the center of the short side of the main surface of the fin in the fins. The heat radiating structure according to any one of claims 1 to 4.

6. The predetermined interval is set such that half of the length of the predetermined interval is shorter than the length of the short side of the main surface of the fin, The length of the short side of the main surface of the fin is set shorter than the length between the fins located at one end and the other end in the direction in which the fins are arranged. The heat radiating structure according to claim 5.

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