JP2001111276A - Heat sink and hood for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cooling efficiency by efficiently introducing cooling air to a cooling fin in a heat sink. SOLUTION: This heat sink is formed of a material superior in thermal conductivity and is provided with a plurality of radiation fins on the upper surface of a base part 1. An air-lead guide part 4, composed of inclined surface having gradually increased height toward the top edge, is provided on at least one side edge of the base part 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat sink and a hood for a heat sink.

[0002]

2. Description of the Related Art Conventionally, a heat sink used for cooling a heating element such as a CPU is formed of a material having good thermal conductivity such as aluminum, and is attached to the heating element via an adhesive or a heat conductive compound. It consists of a base part in contact and a plurality of radiating fins standing upright on the upper surface of the base part.

[0003] Cooling air is blown into a housing for accommodating a substrate on which the CPU and the like are mounted, for example, by a cooling fan or the like, and heat generated from the heat generating element is radiated from the radiating fins through the base portion.

[0004]

However, in recent years, the heat sink has been increasing in size with an increase in the amount of heat generated in the heating element, and the thickness of the base portion has also increased with the decrease in the chip size. I have. Increasing the thickness of the base portion is indispensable for promoting heat diffusion.However, when the thickness of the base portion is increased, the cooling air blown to the heat sink side collides with the end face of the base portion. Since it is blown upward and cannot pass between the radiation fins, the amount of air supplied to the space between the radiation fins decreases, and the cooling efficiency decreases. Further, the rising airflow functions as an air curtain for the cooling airflow toward the radiation fins, so that the amount of cooling airflow to the radiation fins is reduced, and as a result, the cooling efficiency is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and provides a heat sink and a heat sink hood capable of improving cooling efficiency by efficiently guiding cooling air to cooling fins. With the goal.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a heat sink formed of a material having excellent heat conductivity and having a plurality of radiating fins 2, 2,... This is achieved by providing a heat sink in which at least one side edge of the base portion 1 is provided with a wind guide portion 4 having an inclined surface whose height gradually decreases as approaching the leading edge.

The heat sink 3 is fixed on the heating element 10 in such a manner that one edge of the heat guide 3 is substantially perpendicular to the flow direction A of the cooling air. By forming the wind guide portion 4, the edge perpendicular to the cooling air becomes thin, so that the cooling air does not collide with the end face of the base portion 1 and is not blown up. As indicated by A ′, the air is gradually raised along the air guide 4 and is guided between the radiating fins 2.

As shown in FIG. 3 (a), the air guide 4 may be formed in a rectangular area having one side to which the cooling air is applied, but as shown in FIG. In this configuration, it is possible to form a trapezoidal shape in which the dimension in the width direction gradually increases as approaching the edge, and in such a configuration, the side walls 4a, 4a of the air guide unit 4 transfer the cooling air to the center of the heat sink 3. Since it functions as a side guide leading to the portion, the cooling efficiency of the heating element 10 can be further improved. In this case, as shown in FIG. 2 (a), if the side walls 4a, 4a of the air guide 4 are formed by inclined surfaces that are gradually opened upward, the cooling air blows up at the side walls 4a. Can be reduced as much as possible.

The radiating fins 2 may have a suitable cross-sectional shape. As shown in FIGS. 3C and 3D, the heat-radiating fins 2 are formed in a thin shape having a middle and high cross-sectional shape at a central portion. The direction of the maximum inclination line of the wind guide unit 4, that is,
By arranging the cooling air flow direction A so that the longitudinal center line thereof is aligned, it is possible to improve the heat exchange efficiency of each radiating fin 2 while minimizing an increase in pressure loss.

Further, as shown in FIG.
When the skirt portion 5 having a downwardly inclined surface extends forward and downward from the leading edge of the fin, the cooling air flowing along the mounting board 11 can be guided between the radiating fins 2 and 2, The amount of air supplied between the two can be increased.

Further, as shown in FIG. 7, at least one edge of the base portion 1 is covered with the eaves 6 so that a collision occurs at the leading edge of the base portion 1 and the flow direction is changed upward. Since the wind can be reflected again between the radiation fins 2 and 2 by the eaves portion 6 as shown by the arrow B, the cooling efficiency can be improved. It is sufficient that the eaves portion 6 is provided in a range where the upward flow at the leading edge of the base portion 1 can be reflected. Note that the leading edge of the base portion 1 may be a mere vertical rising edge as in the conventional case, or may be the one provided with the wind guide portion 4 as described above.

[0012]

1 and 2 show an embodiment of the present invention. The heat sink 3 is made of a material having good thermal conductivity, such as aluminum or an aluminum alloy.
.. formed upright. The manufacture of the heat sink 3
It can be made by casting, cold forging, cutting, or the like.

The base 1 has a predetermined thickness t,
A stud insertion hole 1a for fixing to the heating element 10 is provided through the center. Opposition 2 of this base part 1
A wind guide section 4 is formed at the periphery. The wind guide portion 4 is formed in a trapezoidal region that gradually narrows as it approaches the center of the base portion 1 in plan view, and its surface gradually increases as it approaches the center portion of the base portion 1 from the leading edge. The inclined surface reaches the thickness of the part. It is also possible to set the thickness at the leading edge of the inclined surface to 0, and to form the leading edge as a knife edge. However, in order to prevent turning up during transport and mounting work, the thickness at the peripheral edge is set to mm. It is desirable to have a degree or a round surface. Further, both side walls 4a, 4a of the wind guide unit 4 are inclined surfaces connecting the surface of the base unit 1 and the surface of the wind guide unit 4.

The radiating fin 2 has a thin shape having a thickness of about 0.5 mm, a length of about 5 mm, and a height of about 21 mm. (A line segment drawn from an arbitrary point on the surface of the portion 4 in a direction in which the inclination angle becomes the maximum), that is, along a direction parallel to the edge adjacent to the edge where the wind guide portion 4 is formed. Are arranged at an equal pitch with a gap of about 2 mm. The heat radiation fins 2, 2,... Are aligned in a straight line along the maximum inclination line direction, and are arranged at a predetermined pitch in a direction orthogonal to the maximum inclination line direction. Is formed. Each radiation fin 2 has an elongated rectangular cross section as shown in FIG. 3 (b), but has a central portion curved outward as shown in FIG. 3 (c), or as shown in FIG. 3 (d). As described above, the fins 2, 2
The pressure loss of the cooling air passing through the gap can be reduced.
Further, the radiating fins 2 that interfere with the circular area concentric with the stud insertion hole 1a are cut out to form a nut receiving recess 3a.

Although the radiating fins 2 are formed in the shape of a thin piece in the illustrated example, they may be formed in a commonly used plate shape or pin shape. Further, in FIG. 1, the wind guide portion 4 is formed at the front and rear end edges to maintain compatibility of the mounting posture, but may be formed only at the side edge facing the flow direction of the cooling air. Further, although the air guide 4 is formed in a trapezoidal area in plan view in FIG. 1, the entire edge may be inclined forward and downward as shown in FIG. Further, the heat radiation fins 2 are arranged on the upper surface of the base portion 1 where the wind guide portions 4 are not provided, but may also be erected on the wind guide portions 4 as shown in FIG. it can. In addition, when the wind guide unit 4 is formed in a trapezoidal shape and the side wall 4a is an inclined surface, the radiating fins 2 can be erected on the side wall 4a.

As shown in FIGS. 1 and 2, the heat sink 3 has a heating element mounted on the mounting board 11 so that the direction of the maximum inclination line of the air guide 4 coincides with the flow direction A of the cooling air. 10 is used fixed on. In the fixed state, the longitudinal direction of the radiating fins 2 substantially coincides with the flow direction A of the cooling air, and the cooling air that has proceeded as shown by the arrow A ′ in FIG. It is gently guided along the surface to the upper surface of the base portion 1 and passes between the radiation fins 2.

FIG. 4 shows a modification of the second embodiment of the present invention for improving the efficiency of heat exchange with cooling air. In the following embodiments, components that are substantially the same as those in the above-described embodiments are given the same reference numerals in the drawings, and descriptions thereof are omitted.

In this embodiment, a high heat transfer body 12 having better heat conductivity than at least the material forming the base 1 is fixed to the base 1. In this embodiment, the base portion 1 and the radiation fins 2 are manufactured by aluminum die casting, and the high heat transfer body 12 is manufactured by copper or aluminum. As shown in FIG. 4B, the high heat transfer body 12 is fixed on a central rear surface of the base portion 1 and in a slightly wider range than the heating element 10.

Therefore, in this embodiment, when the heat sink 3 is fixed on the heating element 10, the high heat transfer body 12 exposed on the back surface from the base portion 1 is formed by the heating element 1.
Directly abuts 0. As a result, the heat generated from the heating element 10 is quickly transmitted to the high heat transfer body 12 and diffused through the high heat transfer body 12, so that the thermal resistance at the contact interface with the heating element 10 is reduced, and The effect is improved. In addition, high heat transfer body 1
Even when a metal material having a large specific gravity is used for 2, the overall weight can be reduced by combining it with a lightweight heat conductor.

As shown in FIG. 4B, the high heat transfer body 12 may be a rectangular plate,
As shown in FIG. 4 (c), a plurality of stripes can be arranged. Further, the fixing to the base portion 1 is performed when a fitting groove is previously formed in the base portion 1 and the high heat transfer body 12 is mechanically fitted thereto, or when the heat sink 3 is formed by a casting method. The outsert molding of the high heat transfer body 12 can also be performed.

Although FIG. 4 shows the case where the high heat transfer body 12 is exposed only on the back surface of the base portion 1, it can also be exposed on the surface of the air guide 4 as shown in FIG. .

FIG. 6 shows a third embodiment of the present invention.
This embodiment shows a deformation for effectively guiding the cooling air to the cooling air flow path between the radiation fins 2, 2, and a skirt portion 5 extends forward from the front end of the air guiding guide portion 4. You. The surface of the skirt portion 5 is formed by a downwardly inclined surface, and the front end extends to near the surface of the mounting board 11.

Therefore, in this embodiment, since the cooling air flowing along the surface of the mounting board 11 can be guided between the radiating fins 2, 2, the cooling air can be effectively used. The skirt portion 5 can be formed integrally with the base portion 1 as shown in FIG.
As shown in FIG. 6B, another member can be fixed to the base portion 1 by caulking, or can be fixed using screws.

FIG. 7 shows a fourth embodiment of the present invention.
In this embodiment, a heat sink hood 9 having a rectangular cylindrical frame 7 is fixed to one side edge of the heat sink 3. The bottom wall 7b of the main body tube portion 7 is provided with a notch 7c through which a boss 1b protruding from the back surface of the base portion 1 of the heat sink 3 can be inserted, and the boss 1b is inserted through the notch 7c. After fitting the part 7 to one end of the heat sink 3, the tip of the boss 1 b is caulked and fixed to the heat sink 3.

The hood 9 includes a baffle tube portion 8 extending forward from the front end of the main body tube portion 7. The air guide tube portion 8
A skirt portion 5 having a hollow rectangular cross section having an opening area gradually expanding toward the front, extending downward and approaching the mounting board 11 side, and an inclined side wall 9a expanding on both sides;
The cooling air flowing toward the heat sink 3 is guided to a cooling air flow path between the radiating fins 2 and 2.

Further, the ceiling wall 7a of the main body cylindrical portion 7 is in contact with the upper end 2a of the radiation fin 2, and the eave portion 6 extends rearward from the rear end of the ceiling wall 7a. The eaves portion 6 abuts against the leading edge of the base portion 1 of the heat sink 3, or reflects the cooling air turned upward by the inclined surface of the wind guide portion 4 or the skirt portion 5 again to the surface side of the base portion 1. It is provided in order to make it.

Therefore, in this embodiment, since the cooling air flowing in the area not inserted between the radiation fins 2 can be guided between the radiation fins 2 and used for cooling, the cooling efficiency can be improved. Also, as shown by the arrow B in FIG. 7A, the upwardly directed cooling air can be reflected again by the eaves 6 and returned to the space between the radiating fins 2, so that the cooling air can be effectively used. . Furthermore, since the hood 9 is fitted and fixed to the front edge of the heat sink 3, the heat sink 3
It is easier to install than when the entire upper surface is large, and does not increase the cost.

[0028]

As is apparent from the above description, according to the present invention, since the cooling air can be effectively guided between the radiation fins, the cooling efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing the present invention.

FIGS. 2A and 2B are side views of FIG. 1, wherein FIG. 2A is a view in the direction of arrow 2A in FIG. 1, and FIG. 2B is a sectional view taken along line 2B-2B in FIG.

3A and 3B are views showing a modification of FIG. 1, wherein FIG. 3A is a plan view showing the vicinity of a wind guide unit, FIG. 3B is a plan view showing a radiation fin, and FIG. 3C is a modification of the radiation fin. Plan view, (d)
It is a top view which shows the other deformation of a radiation fin.

FIG. 4 is a diagram showing a second embodiment of the present invention, in which (a)
Is a sectional view corresponding to FIG. 2B, FIG.
(C) is a rear view showing the deformation of (b).

5A and 5B are diagrams showing a modification of FIG. 4, wherein FIG.
And (b) is a back view.

FIG. 6 is a diagram showing a third embodiment of the present invention, in which (a)
2 is a cross-sectional view corresponding to FIG. 2B, and FIG. 2B is a cross-sectional view showing a modification of FIG.

FIG. 7 is a diagram showing a fourth embodiment of the present invention, in which (a)
7B is a cross-sectional view corresponding to FIG. 2B, and FIG. 7B is a view taken in the direction of arrow 7B in FIG. 7A.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base part 2 Heat radiation fin 3 Heat sink 4 Wind guide part 5 Skirt part 6 Eave part 7 Main body cylinder part 7a Ceiling wall 8 Wind guide cylinder part 9 Hood

Claims (7)

[Claims] 1. A heat sink formed of a material having excellent heat conductivity and having a plurality of radiating fins erected on an upper surface of a base portion, wherein at least one edge portion of the base portion gradually becomes closer to a leading edge. A heat sink provided with a wind guide portion formed of an inclined surface having a reduced height. 2. The heat sink according to claim 1, wherein the wind guide portion has a trapezoidal shape in a plan view, the dimension of which in the width direction gradually increases as approaching the leading edge. 3. The heat sink according to claim 2, wherein both side walls of said air guide are formed as inclined surfaces which are gradually opened upward. 4. The radiating fin according to claim 1, wherein the radiating fin is formed in the shape of a thin plate having a middle and high cross-sectional shape at a central portion, and is arranged along the direction of the maximum inclined line of the wind guide portion. heatsink. 5. The heat sink according to claim 1, wherein a skirt portion having a downwardly inclined surface is extended from a leading edge of the air guide portion. 6. A heat sink formed of a material having excellent heat conductivity and having a plurality of radiating fins erected on an upper surface of a base portion, wherein an upper portion of one side edge of the base portion is covered by an eave portion, and a base portion is provided. A heat sink that reflects the cooling air that has turned upward at the leading edge of the base toward the surface of the base at the eaves. 7. An air guide tube portion having an opening area gradually increasing from a main tube portion having a hollow rectangular cross section toward the tip, and a plurality of radiating fins are erected on a base portion. A heat sink hood that is fitted and fixed to one edge of the heat sink that is provided. The cooling wall, which collides with the front end of the base portion and changes direction upwards, is reflected between the radiation fins on the ceiling wall of the main body cylindrical portion. Hood for heat sink with eaves to be extended.