JP6132869B2 - heatsink - Google Patents

Description

  The present invention relates to a heat sink for cooling a heat generating element, for example.

In recent years, since the heat generation density of heat generating elements such as CPUs, LSIs, and power semiconductor elements has increased and become high temperature, the heat dissipation performance required for heat sinks has been increasing year by year.
The heat radiation performance of the heat sink increases as the heat radiation area per unit volume of the heat radiation fin provided on the heat sink increases.
The heat dissipating area per unit volume of the heat dissipating fins increases as the distance between adjacent heat dissipating fins decreases. Depending on the usage environment, there may be a lower limit on the distance between the radiating fins. Therefore, how to increase the heat dissipating area per unit volume of the heat dissipating fin within the restriction of the gap between the heat dissipating fins is the key to improving the heat dissipating performance of the heat sink.
Conventionally, a heat sink in which regular hexagonal fins are regularly arranged is known (see, for example, Patent Document 1).

FIG. 17 is a view showing the arrangement of the radiation fins 3 of the heat sink in the above-mentioned patent document.
In this heat sink, the arrangement of the plurality of radiating fins 3 is such that the side surfaces of the regular hexagonal first sides of the radiating fins 3 face the first side along the first direction which is the direction of the wind. The second side adjacent to the first side of the regular hexagon of each radiating fin is aligned with respect to the first side with respect to the first direction. The side wall surface of the second side and the side wall surface of the fifth side opposite to the second side are aligned in parallel along the second direction of the angle formed, and each side of the first direction Radiation fin 3 The sixth side adjacent to the first side of the regular hexagon faces the side wall surface of the sixth side and the sixth side along the third direction of the angle formed by the sixth side adjacent to the first side. The side wall surface of the third side is aligned in parallel.

Japanese Patent No. 3840970

  In the heat sink, for each of the first to sixth sides of the regular hexagon, the side surfaces of the corresponding sides of the adjacent radiation fins 3 are positioned on the extended surface of the side wall surface of the side, Therefore, as indicated by the hatched lines in FIG. 18, there is a problem that there is a limit to the improvement of the heat radiation area per unit volume of the heat radiation fin because the area of the empty area 7 is large between the adjacent heat radiation fins 3. .

  An object of the present invention is to solve such a problem, and while maintaining the lower limit of the distance between adjacent radiating fins provided to prevent clogging of dust, the radiating fins An object of the present invention is to obtain a heat sink capable of increasing the heat radiation area per unit volume and improving the heat radiation performance.

The heat sink according to the present invention is a heat sink in which a plurality of heat radiation fins are provided on a base,
Each of the radiating fins has a regular polygonal cross-sectional shape,
Further, the adjacent radiating fins are arranged such that the side surfaces face each other and the distance between the side surfaces, which is the distance between the side surfaces facing each other apart from each other, is equal.

  According to this invention, while maintaining the lower limit of the distance between the fin side surfaces provided to prevent clogging of dust, etc., the heat radiation area per unit volume of the heat radiation fin is increased, and the heat radiation performance is enhanced. Can do.

It is a disassembled perspective view which shows the heat sink of Embodiment 1 of this invention. It is a top view which shows the radiation fin and base of FIG. It is the figure which expanded the site | part of A of FIG. It is the schematic diagram which looked at the radiation fin in the heat sink of FIG. 2 in the paper surface perpendicular direction. When the circumscribed radius of the heat dissipating fin in the heat sink of FIG. 1 is r, the distance between the fin side surfaces is t, and r / t = α, 12α / (value obtained by dividing t from the heat dissipating area per unit volume of the heat dissipating fin. This is a graph with √3 + α) (3 + √3α) on the vertical axis and α on the horizontal axis. It is a top view which shows the radiation fin and base of the heat sink of Embodiment 2 of this invention. It is the figure which expanded the site | part of B of FIG. It is the schematic diagram which looked at the radiation fin in the heat sink of FIG. 6 in the paper surface perpendicular | vertical direction. In the heat sink of FIG. 6, when the circumscribed radius of the radiating fin is r, the distance between the fin side surfaces is t, and r / t = α, 8√2α which is a value obtained by dividing t from the radiating area per unit volume of the radiating fin. / (2 + √2α) is a graph with ² on the vertical axis and α on the horizontal axis. It is a top view which shows the radiation fin and base of the heat sink of Embodiment 3 of this invention. It is the figure which expanded the site | part of C of FIG. It is the schematic diagram which looked at the radiation fin in the heat sink of FIG. 10 in the paper surface perpendicular | vertical direction. When the circumscribed radius of the heat dissipating fin in the heat sink of FIG. 10 is r, the distance between the fin side surfaces is t, and r / t = α, 4α / (value obtained by dividing t from the heat dissipating area per unit volume of the heat dissipating fin. α + 1) is a graph with ² on the vertical axis and α on the horizontal axis. It is a top view which shows the radiation fin in the heat sink of Embodiment 4 of this invention. It is a top view which shows the radiation fin in the heat sink of Embodiment 5 of this invention. It is a top view which shows the radiation fin in the heat sink of Embodiment 6 of this invention. It is a figure which shows arrangement | positioning of the radiation fin of the conventional heat sink. It is the figure which showed the empty area | region without the radiation fin of the heat sink of FIG. 17 with the oblique line.

  Hereinafter, embodiments of the heat sink according to the present invention will be described with reference to the drawings. In the drawings, the same or equivalent members and parts will be described with the same reference numerals.

Embodiment 1 FIG.
FIG. 1 is an exploded perspective view showing a heat sink according to Embodiment 1 of the present invention.
The heat sink includes a base 2 on which the heating element 1 is installed, a plurality of radiating fins 3 provided on the back surface of the base 2, a jacket 4 in which the base 2 is accommodated, and a side surface facing the jacket 4. A refrigerant inlet portion 5 and a refrigerant outlet portion 6 are provided.

In this heat sink, the refrigerant enters the space between the jacket 4 and the base 2 through the refrigerant inlet 5 as shown by an arrow A in FIG. In this space, the refrigerant exchanges heat with the heat radiating fins 3 that have received heat from the heat generating elements 1, and the heat generating elements 1 are cooled through the heat radiating fins 3. The refrigerant that has received heat by heat exchange with the heat radiating fins 3 is directly discharged to the outside of the heat sink through the refrigerant outlet portion 6.
The refrigerant may be liquid, gas, or gas-liquid mixture. Further, depending on the environment in which the heat sink is installed, the jacket 4 is not necessarily required and may be omitted.

FIG. 2 is a plan view showing the radiation fins 3 and the base 2 in FIG. 1, and FIG. 3 is an enlarged view of a portion A in FIG.
The radiating fin 3 is a regular hexagon having a circumscribed circle radius r in cross-sectional shape. The heat dissipating fins 3 are arranged such that six heat dissipating fins 3 are adjacent to each other around one heat dissipating fin 3. Each side of one radiating fin 3 faces each side of each surrounding radiating fin 3.
The distance between the side surfaces that face each other and face each other at a distance is called the distance between the side surfaces, and this value is t.

In addition, the radiation fin 3 may form a corner R (roundness) at the corner. In this case, the circumscribed circle radius r may be a circumscribed circle radius with respect to the cross-sectional shape of the radiation fin 3 before the corner R is attached.
Further, the heat radiating fins 3 may be tapered from the base 2 in the vertical direction. In this case, the distance t between the side surfaces is the side surface at the average height of the tapered fin 3 (for example, the height at the intermediate portion when the radiator fin 3 is linearly inclined). What is necessary is just a distance.

FIG. 4 is a schematic view of the heat dissipating fin 3 of FIG. 2 as viewed in the direction perpendicular to the paper surface. FIG. 5 shows the circumscribed radius of the heat dissipating fin 3 in the heat sink of Embodiment 1 as r, the distance between the fin side surfaces as t, r / When t = α, 12α / (√3 + α) (3 + √3α), which is the value obtained by dividing t from the heat radiation area per unit volume of the radiation fin 3, is plotted on the vertical axis, and α is plotted on the horizontal axis. It is a graph.
From FIG. 4, when the height of the heat radiating fin 3 is set to h, the volume of the heat radiating fin 3 in the region of the repeating unit of the heat radiating fin 3, which is the region surrounded by the dotted line in FIG. be able to.

  (√3 + α) (3 + √3α) h (1)

  Further, assuming that heat is radiated from the heat radiating fins 3 to the refrigerant from the side, the heat radiating area in the repeating unit of the heat radiating fins 3 can be expressed by equation (2).

  12rh ... (2)

From Formula (1) and Formula (2), the heat radiation area per unit volume in the repeating unit region of the heat radiation fin 3 is
12 rh / {(√3r + t) (3r + √3t) h}
= (1 / t) {12α / (√3 + α) (3 + √3α)} (3)
However, α = r / t.

From equation (3), when 12α / {(√3 + α) (3 + √3α)} takes a maximum value for an arbitrary t, the heat dissipating area of the heat dissipating fin 3 per unit volume at that t is the maximum. I understand that
From FIG. 5, 12α / {(√3 + α) (3 + √3α)} has a maximum value of 1.0 when α = 1.7. Further, when the range of α in which the surface area per unit volume is 70% to 100% of the maximum value is obtained from the equation (3), 0.506 ≦ α ≦ 5.93, and α = t / r relationship Therefore, it can be modified as 0.169t ≦ r ≦ 1.98t.

  From the above, by setting the circumscribed cylindrical radius r of the radiating fin 3 to be 0.1169t ≦ r ≦ 1.98t with respect to an arbitrary distance t between side surfaces, per unit volume in the region of the repeating unit of the radiating fin 3 Since the heat radiation area can be set to 70% to 100% of the maximum value, the restriction on the lower limit of the distance t between the side surfaces provided to prevent clogging of dust and the like is set. However, the heat radiation performance can be particularly improved within the constraints.

Embodiment 2. FIG.
6 is a plan view showing the base 2 provided with the radiation fins 3 in the heat sink according to Embodiment 2 of the present invention, and FIG. 7 is an enlarged view of a portion B in FIG.
The radiating fin 3 in the second embodiment is a square with a cross-sectional shape of a circumscribed circle radius r, and the radiating fin 3 is arranged such that four radiating fins 3 are adjacent to one radiating fin 3, In this arrangement, the distance between the side surfaces of adjacent radiating fins 3 is t.
Other configurations are the same as those of the heat sink of the first embodiment.

In addition, the radiation fin 3 may form a corner R (roundness) at the corner. In this case, the circumscribed circle radius r may be a circumscribed circle radius with respect to the cross-sectional shape of the radiation fin 3 before the corner R is attached.
Further, the heat radiating fins 3 may be tapered from the base 2 in the vertical direction. In this case, the distance t between the side surfaces is the distance between the side surfaces at the average height of the tapered radiating fins 3 (for example, the height at the intermediate portion when the radiating fins 3 are linearly inclined). It may be a distance.

FIG. 8 is a schematic view of the radiating fins 3 in the heat sink of the second embodiment when viewed in the direction perpendicular to the paper surface.
FIG. 9 shows a value obtained by dividing t from the heat radiation area per unit volume of the heat radiation fin 3 when the circumscribed radius of the heat radiation fin 3 is r, the distance between the fin side surfaces is t, and r / t = α. 2α / (2 + √2α) ² is a graph with ² on the vertical axis and α on the horizontal axis.

  When the height of the radiating fin 3 is set to h, the volume of the region of the repeating unit of the radiating fin 3 is expressed by equation (4).

(2 + √2α) ² h (4)

  Further, assuming that heat is radiated from the radiating fins 3 to the refrigerant from the side, the radiating area in the repeating unit of the radiating fins 3 is expressed by the equation (5).

  8√2rh ... (5)

  From the equations (4) and (5), the heat radiation area of the heat radiation fin 3 per unit volume in the repetitive unit region of the heat radiation fin 3 is expressed by the equation (6).

8√2 rh / {(2 + √2α) ² h}
= (1 / t) {8√2α / (2 + √2α) ² } (6)
However, α = r / t.

From equation (6), it can be seen that when 8√2α / (2 + √2α) ² takes the maximum value for an arbitrary t, the heat dissipating area of the heat dissipating fin 3 per unit volume at that t is maximized.
From FIG. 9, 8√2α / (2 + √2α) ² takes a maximum value of 1.0 when α = 1.39. Furthermore, when the range of α in which the surface area per unit volume of the radiating fin 3 is 70% to 100% of the maximum value is obtained from Equation (6), 0.413 ≦ α ≦ 4.84, and α = t From the relationship of / r, it can be transformed to 0.207t ≦ r ≦ 2.42t.

From the above, the heat radiation area per unit volume of the radiation fin 3 can be maximized by setting the range of the circumscribed cylinder radius r of the radiation fin 3 to 0.207t ≦ r ≦ 2.42t with respect to an arbitrary distance t between side surfaces. When the restriction of the lower limit value provided in order to prevent clogging with dust etc. is set in the distance t between the side surfaces, which is the gap between the radiating fins 3, Even so, the heat dissipation performance can be particularly improved within the constraints.
Since the heat radiation area per unit volume of the heat radiation fin 3 is increased, the heat radiation performance of the heat sink is improved.

Embodiment 3 FIG.
FIG. 10 is a plan view showing the base 2 provided with the radiation fins 3 in the heat sink of Embodiment 3 of the present invention, and FIG. 11 is an enlarged view of a portion C in FIG.
The radiating fins 3 in the third embodiment are equilateral triangles having a circumscribed circle radius of r, and the radiating fins 3 are arranged so that three radiating fins 3 are adjacent to each other around one radiating fin 3. In this arrangement, the distance between the side surfaces of the radiation fins 3 is t.
Other configurations are the same as those of the heat sink of the first embodiment.

In addition, the radiation fin 3 may form a corner R (roundness) at the corner. In this case, the circumscribed circle radius r may be a circumscribed circle radius with respect to the cross-sectional shape of the radiation fin 3 before the corner R is attached.
Further, the heat radiating fins 3 may be tapered from the base 2 in the vertical direction. In this case, the distance t between the side surfaces is the distance between the side surfaces at the average height of the tapered radiating fins 3 (for example, the height at the intermediate portion when the radiating fins 3 are linearly inclined). It may be a distance.

FIG. 12 is a schematic view of the radiating fins 3 in the heat sink of Embodiment 3 as viewed in the direction perpendicular to the paper surface.
FIG. 13 shows the relationship between the radiation area per unit volume of the radiation fin 3 and t when the circumscribed radius of the radiation fin 3 in the heat sink of Embodiment 3 is r, the distance between the fin side surfaces is t, and r / t = α. 4 is a graph in which 4α / (α + 1) ² of the value obtained by dividing is taken on the vertical axis and α is taken on the horizontal axis.

  When the height of the radiating fin is set to h, the volume of the region of the repeating unit of the radiating fin 3 is expressed by equation (7).

  (3r + 3t) (√3r + √3t) h (7)

  Further, assuming that heat is radiated from the radiating fins 3 to the refrigerant from the side, the radiating area in the repeating unit of the radiating fins 3 is expressed by equation (8).

  12√3 rh (8)

  From Formula (7) and Formula (8), the heat radiation area per unit volume is represented by Formula (9).

12√3 rh / {(3r + 3t) (√3r + √3t) h}
= (1 / t) {4α / (α + 1) ² } (9)
Where α = r / t

From equation (9), it can be seen that when 4α / (α + 1) ² takes the maximum value for a given fin side surface distance t, the heat radiation area per unit volume at that t is maximized.
From FIG. 13, 4α / (α + 1) ² takes a maximum value of 1.0 when α = 0.987.
Furthermore, when the range of α in which the surface area per unit volume is 70% to 100% of the maximum value is obtained from the equation (9), 0.292 ≦ α ≦ 3.42, and α = t / r relationship Therefore, it can be modified as 0.292t ≦ r ≦ 3.42t.

From the above, by setting the range of the circumscribed cylinder radius r of the radiation fin 3 to 0.292 t ≦ r ≦ 3.42 t with respect to the distance t between the fin side surfaces, which is a gap between any adjacent radiation fins, per unit volume The heat radiation area can be 70% to 100% of the maximum value.
Therefore, even when a lower limit constraint is provided in order to prevent dust and the like from being clogged in the gap t between the fin side surfaces, the empty area without the radiation fin 3 is minimized within the constraint. The heat radiation area per unit volume of the radiation fin 3 can be increased, and the heat radiation performance of the heat sink is improved.

Embodiment 4 FIG.
FIG. 14 is a plan view showing heat radiation fin 3 of the heat sink according to the fourth embodiment of the present invention.
The radiating fin 3 of the fourth embodiment has a regular hexagonal cross section, and has an uneven portion 3a on its side surface.
Other configurations are the same as those of the heat sink of the first embodiment.
According to the heat sink of this embodiment, since the uneven portion 3a is provided on the side surface of the radiation fin 3, the flow of the refrigerant flowing between the adjacent radiation fins 3 is agitated, and compared with the heat sink of the first embodiment. Heat dissipation is further promoted.

Embodiment 5. FIG.
FIG. 15 is a plan view showing heat radiation fin 3 of the heat sink according to the fifth embodiment of the present invention.
The heat radiating fin 3 of the fifth embodiment has a regular triangular cross section, and has a concavo-convex portion 3a on its side surface.
Other configurations are the same as those of the heat sink of the third embodiment.
According to the heat sink of this embodiment, since the uneven portion 3a is provided on the side surface of the radiation fin 3, the flow of the refrigerant flowing between the adjacent radiation fins 3 is agitated, compared with the heat sink of the third embodiment. Heat dissipation is further promoted.

Embodiment 6 FIG.
FIG. 16 is a plan view showing heat radiation fin 3 of the heat sink according to the sixth embodiment of the present invention.
The radiating fin 3 of the sixth embodiment has a regular quadrangular cross section, and an uneven portion 3a is formed on the side surface thereof.
According to the heat sink of this embodiment, since the uneven portion 3a is provided on the side surface of the radiation fin 3, the flow of the refrigerant flowing between the adjacent radiation fins 3 is agitated, compared with the heat sink of the second embodiment. Heat dissipation is further promoted.

  In each of the embodiments, the case where the cross-sectional shape is a hexagonal shape, a quadrangular shape, and a triangular shape has been described. However, the present invention may be any heat dissipating fin having a regular polygonal cross section. There may be.

  DESCRIPTION OF SYMBOLS 1 Heating element, 2 base, 3 radiation fin, 3a uneven | corrugated | grooved part, 3b 1st through-hole, 3c 2nd through-hole, 4 jacket, 5 refrigerant | coolant inlet, 6 refrigerant | coolant outlet, 7 vacant area, 8 blocks, 8a small block.

Claims (3)

A heat sink having a plurality of heat dissipating fins on the base,
Each of the radiating fins has a regular polygonal cross-sectional shape,
Further, the adjacent radiating fins are arranged such that the side surfaces are opposite to each other and the distance between the side surfaces, which is the distance between the side surfaces facing each other apart from each other, is equal.
The cross-sectional shape of the radiating fin is a regular hexagon having a circumscribed circle radius of r, and when the distance between the side surfaces is t, between the circumscribed circle radius r and the distance between the side surfaces t,
A heat sink satisfying 0.169t ≦ r ≦ 1.98t. A heat sink having a plurality of heat dissipating fins on the base,
Each of the radiating fins has a regular polygonal cross-sectional shape,
Further, the adjacent radiating fins are arranged such that the side surfaces are opposite to each other and the distance between the side surfaces, which is the distance between the side surfaces facing each other apart from each other, is equal.
The cross-sectional shape of the radiation fin is an equilateral triangle having a circumscribed circle radius of r, and when the distance between the side surfaces is t, between the circumscribed circle radius r and the distance between the side surfaces t,
A heat sink satisfying 0.292t ≦ r ≦ 3.42t. Wherein the said side of the heat radiating fins, the heat sink according to claim 1 or claim 2 uneven portion is formed.

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