US20120305224A1

US20120305224A1 - Heat sink

Info

Publication number: US20120305224A1
Application number: US13/513,507
Authority: US
Inventors: Sung Jin Kim; Juwan Kim; Dong-Kwon Kim
Original assignee: Korea Advanced Institute of Science and Technology KAIST
Current assignee: Korea Advanced Institute of Science and Technology KAIST
Priority date: 2009-12-02
Filing date: 2009-12-02
Publication date: 2012-12-06
Also published as: WO2011068259A1; CN102713486A

Abstract

A heat sink provided. In the heat sink in accordance with an embodiment of the present invention, a heat dissipation plate forms a channel between each of stages by isolating a plurality of heat dissipating fins in equal intervals and arranging the heat dissipating fins in a multi-stage circle shape. Then, the heat sink forms a path between the sequentially isolated heat dissipating fins at each of the stages. Also, a centrifugal fan alternatively blocks the channel and path at each of the stages through a rotation by a plurality of blades arranged in a multi-stage circle shape to be positioned between the channels. Then, the centrifugal fan is capable of inflowing outer air to discharge the air by generating a pressure difference of inter/outer air through a combination of the blade and the heat dissipation plate.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates generally to heat sinks. More particularly, the invention relates to a heat sink for enhancing cooling efficiency due to the improvement of air flow generated by splitting zones of heat dissipation fins, which are configured with a multi-stage concentric circle shape after the heat dissipation fins and blades are arranged in a multi-stage circle shape and mutually combined.
2. Description of the Related Art
Due to the current trend toward highly integration, highly efficiency, miniaturization of semiconductor chips, packages, and the like, electronic components become highly efficient rapidly. Accordingly, there have been various attempts to maintain efficiency of electronic components by efficiently and rapidly discharging heat generated while operating the electronic components. This heat discharging is associated with the development in the electronic components.
Particularly, as the capacity of CPUs and peripheral electronic elements become relatively large, heat amount is extremely increased.
To stably secure functions of electronic components, cooling means have been adopted.
To solve the aforementioned problems in the prior art, Korean Laid-Open Patent Publication No. 2004-52010 entitled “Apparatus for cooling electronic chip” that was previously proposed discloses a terminal base transfers the heat by directly contacting to a heated element such as a CPU. Heat pipes are soldered to an upper part of the terminal base. Heat radiating blocks are soldered to an end of the heat pipe. A fan motor supplies a cooling fluid to the heat radiating block by placing to a center of the heat radiating block. A base frame fixes the fan motor and the terminal base. A fan cover efficiently inflows/discharges the cooling fluid by blocking a majority portion excepting the upper center of the part installing the fan motor. The fan cover formed to a lower side of the heat pipe is formed as one body by soldering to the heat pipe. Thus, the heat of the heat pipe is transferred/discharged to the air.
In the above mentioned apparatus, heat generated from heating elements such as CPUs is conducted through the terminal base to the heat pipes, and then moved to the heat radiating blocks that are formed at each of ends of the heat pipes. The heat moved to the heat radiating blocks drive the fan motor and creates a forced convection current to be cooled.
Also, Korean Laid-Open Patent Publication No. 2004-52010 entitled “Apparatus for cooling computer parts and method of manufacturing the same” that was previously proposed discloses The apparatus includes a heat transferring block capable of being thermally coupled to the heat generating parts to conduct the heat generated by the heat dissipating parts, at least one heat pipe, each including a block coupling portion thermally coupled to the heat transferring block and a fin coupling portion formed of a generally curved shape composed essentially of one or more circular arc portions, and a plurality of heat dissipating fins, each having at least one perforation hole. The geometry of the curvature of the entirety of the fin coupling portion is shaped so that the geometry alone would not allow the heat pipe to be inserted through the perforation hole of the heat dissipating fins. The fin coupling portion of the heat pipe passes through each of the at least one perforation hole of the plurality of heat dissipating fins. Each of the heat dissipating fins are spaced apart from one another along the fin coupling portion and positioned to the fin coupling portion.
When heat is transferred to the heat transferring block, it escapes through the air through the heat pipe at parts excepting combination parts with the heat transferring block. As a result, the heat is cooled. The plurality of heat dissipating fins can cool electronic components by passing air flow generated from a cooling fan thereinto and discharging the air flow to the outside in a spiral shape with respect to a rotary shaft of the cooling fan.
However, in the above-mentioned apparatus for cooling, there is a problem in that outer air inflows according to a rotary shaft of a fan employing an axial fan and passes heat dissipating fins to be discharged toward an axial direction, thereby reducing cooling efficiency.
In other words, the temperature of the heat dissipating fins is cooled through the axial fan, which is mounted on upper parts of the heat dissipating fins where the heat generated from heating components such as CPUs is transferred. The upper parts of the heat dissipating fins first face with wind created by the axial fan to be cooled, and then lower parts thereof become cooled sequentially.
In this case, the power of the wind by the axial fan is decreased by interference of the heat dissipating fins, thereby reducing cooling efficiency.
Due to the interference of the heat dissipating fins, the cooling power on the lower parts of the heat dissipating fins positioned at a region close to a CPU is reduced. For this reason, the temperature is high on the lower parts of the heat dissipating fins located at a region close to a CPU. To the contrary, on upper parts of the heat dissipating fins located at a region far from the CPU, the temperature is relatively low. As a result, heat discharging efficiency is reduced.

BRIEF SUMMARY OF THE INVENTION

Accordingly, the present invention is to address the above-mentioned problems and/or disadvantages and to offer at least the advantages described below.
An aspect of the present invention is to provide a heat sink. Particularly, one aspect of the present invention is to provide a heat sink for improving inflow and discharging of air by repeatedly splitting each of stages of heat dissipation fins by rotating a centrifugal fan after the centrifugal fan for arranging the heat dissipation fins in a multi-stage concentric circle shape and a heat dissipation plate are mutually combined.
Embodiments of the present invention provide a heat sink comprising: a heat dissipation plate forming a channel between each of stages by isolating a plurality of heat dissipating fins in equal intervals and arranging the heat dissipating fins in a multi-stage circle shape, forming a path between the sequentially isolated heat dissipating fins at each of the stages; and a centrifugal fan alternatively blocking the channel and path at each of the stages through a rotation by a plurality of blades arranged in a multi-stage circle shape to be positioned between the channels, inflowing outer air to discharge the air by generating a pressure difference of inter/outer air through a combination of the blade and the heat dissipation plate.
In some embodiments of the present invention, the heat dissipation plate includes a second flange in which the heat dissipation fins are mounted vertically upward with respect to the second flange, and a motor is set vertically upward on an upper surface of the second flange.
In some embodiments of the present invention, the centrifugal fan prepares a first flange in which the blades are mounted vertically downward with respect to the blade to form an inflow hole and is rendered to be rotated by fixing a rotary shaft of the motor by a connection hole of a combination block after positioning the combination block supported by a rib at a center of the inflow hole.
In some embodiments of the present invention, the path is a space between the sequentially isolated heat dissipation fins at equal intervals and has a virtual arc shape which is radiated outwardly from a center of the second flange under the condition that the heat dissipation fins are arranged in a multi-stage concentric circle shape.
In some embodiments of the present invention, the blades are arranged to be crossed between the channels and paths of each of stages in the heat dissipation plate.
In some embodiments of the present invention, the heat dissipation fins and blades have an incline line on one side thereof, and the incline lines has an angle inside from outside thereof toward a rotational direction of the heat dissipation plate.
Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

ADVANTAGEOUS EFFECTS

As above mentioned, a heat sink according to the present invention, after the centrifugal fan for arranging heat dissipation fins in a multi-stage concentric circle shape and a heat dissipation plate are mutually combined, repeatedly splits each of stages of heat dissipation fins by rotating a centrifugal fan to generate an internal/external pressure difference of the heat sink, so that external air flow is increased, thereby improving cooling efficiency.
Furthermore, the heat sink according to the present invention is formed by superimposing the centrifugal fan and dissipation plate, thereby minimizing a volume. As a result, the miniaturization of products is possible.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded, perspective view illustrating a heat sink in accordance with an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a heat sink in accordance with an embodiment of the present invention.

FIG. 3 is a side sectional view illustrating a heat sink in accordance with an embodiment of the present invention.

FIG. 4 is a front view illustrating a heat dissipation plate of a heat sink in accordance with an embodiment of the present invention.

FIG. 5 is a front view illustrating a centrifugal fan of a heat sink in accordance with an embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a heat sink in accordance with an embodiment of the present invention.

FIG. 7 is a photograph showing an experimental test of a heat sink in accordance with an embodiment of the present invention.


<Brief explanation of essential
parts of the drawings>

	10: Heat sink,	100: Centrifugal Fan,
	110: First Flange,	111: Inflow Hole,
	120: Rib,	130: Combination Block,
	131: Connection Hole,	140: Blade,
	150: Incline Line,	200: Heat Dissipation Plate,
	210: Second Flange,	220: Motor,
	221: Rotary Shaft,	230: Heat Dissipation fin,
	240: Channel.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary, non-limiting embodiments of the present invention will now be described more fully with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, the disclosed embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The principles and features of this invention may be employed in varied and numerous embodiments without departing from the scope of the invention.
Furthermore, well known or widely used techniques, elements, structures, and processes may not be described or illustrated in detail to avoid obscuring the essence of the present invention. Although the drawings represent exemplary embodiments of the invention, the drawings are not necessarily to scale and certain features may be exaggerated or omitted in order to better illustrate and explain the present invention.
FIG. 1 is an exploded, perspective view illustrating a heat sink in accordance with an embodiment of the present invention. FIG. 2 is a perspective view illustrating a heat sink in accordance with an embodiment of the present invention. FIG. 3 is a side sectional view illustrating a heat sink in accordance with an embodiment of the present invention. FIG. 4 is a front view illustrating a heat dissipation plate of a heat sink in accordance with an embodiment of the present invention. FIG. 5 is a front view illustrating a centrifugal fan of a heat sink in accordance with an embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating a heat sink in accordance with an embodiment of the present invention. FIG. 7 is a photograph showing an experimental test of a heat sink in accordance with an embodiment of the present invention.
As shown in FIGS. 1 to 6, a heat sink 10 according to the present invention comprises a heat dissipation plate 200 and a centrifugal fan 100.
The heat sink 10 generates a pressure difference of inter/outer air to inflow outer air thereinto. Then, the heat sink discharges outer air to the outside, so that a heat exchanging mechanism occurs.
The heat dissipation plate 200 includes a second plate flange 210. A motor 220 is fixed vertically upward at a center of an upper surface of the second flange 210. A rotary shaft 221 of the motor is positioned upward.
And, a heat dissipation fin 230 with a face is mounted to be located upright on the upper surface of the second flange 210
In this case, a plurality of heat dissipation fins 230 are isolated at a predetermined interval and arranged in a circle at the same time. Between isolated spaces of the heat dissipation fins 230, a path 250 for inducing air flow is formed.
The path 250 is a space between the sequentially isolated heat dissipation fins 230 at equal intervals and has a virtual arc shape which is radiated outwardly from a center of the second flange 210 under the condition that the heat dissipation fins 230 are arranged in a multi-stage concentric circle shape.
The plurality of heat dissipation fins with a circular structure are arranged in the multi-stage concentric circle shape, thereby slowing down air flow between each of the stages, so that a channel 240 for heat exchanging in the heat dissipation fin 230 is formed.
The channel 240 is at least one or more, and the following descriptions will be given on the assumption that the number of the channel 240 is four and formed as four stages in the present invention.
And, the centrifugal 100 includes a first plate flange 110. A plurality of blades 140 with faces that are vertically downward 110 are mounted on a lower surface of the first flange
The blades 140 are arranged in a multi-stage concentric circle shape to be positioned between the channels 240. The position of the blade 140 at each of the stages is arranged to be crossed, so that the blade 140 alternatively interrupts the channel 240 and path 250 at each of the stages.
One side of the heat dissipation fin 230 and blade 140 has an incline line. The incline line has an angle inside from outside thereof toward a rotational direction of the centrifugal fan 100. Accordingly, air can smoothly flow at a step type at each of the stages of the channel 240.
Moreover, the centrifugal fan 100 forms an inflow hole 111 at a center of the first flange 110. The centrifugal fan 100, after positioning a combination block 130 supported by a rib 120 at a center of the inflow hole 111, is rendered to be rotated by fixing the rotary shaft 221 of the motor 220 by the connection hole 131 of the combination block 130 in the heat dissipation plate 200.
The heat sink 10 with above-mentioned structure according to the present invention is adheredly mounted to an electronic component for requiring a cooling system.
Hereinafter, the heat sink according to the present invention will be described in more detail later.
In advance, the following descriptions will be given on the assumption that the channel 240 located most inside the blades 140 and heat dissipation fin 230 arranged in a multi-stage concentric circle shape is a first stage, and the channels located outside the first stage are a second step, and a third step, respectively.
When the rotary shat 221 is rotated by applying a drive signal to the motor 220, the first flange 110 rotates the blade 140 in line with the combination block, which is fixed in one entity with the rotary shaft 221.
Here, the blade 140 becomes rotated in each of the channels 240 of the heat dissipation plate 200.
Outer air inflows into the inflow hole 111 of the centrifugal fan 100, and then inflows into the channel of the second stage through the path 250 of the first stage. The inflown air flows to the channels between front and rear sides of two heat dissipation fins 230 located at the channel 240 of the second stage through the blade 140 of the second stage.
At this time, the air is thermally conducted and then flows to channel 240 of the third step through the path 250. This process is repeatedly performed, so that the air is discharged to the outside through the path 250, which is located most outside.
Like this, when air flow is performed in the heat dissipation fin 230, the heat dissipation plate 200 receiving heat through the second flange 200 adhered to an electronic component for requiring cooling can be cooled by inflowing outer air.
Experimental embodiments of a heat power in the heat sink 10 according to the present invention will be described below under the following condition.
A heater is connected to a bottom surface of the heat sink 10. Then, heat is provided to set up a general heat environment of electronic components. To measure heat temperature varied depending on the number of revolutions of the centrifugal fan in the heat sink 10, an apparatus for measuring heat is prepared.
The value measured by the above apparatus is shown in Table 1.

	TABLE 1

	RPM of	Thermal
	heat sink	resistance (K/W)

	550	0.87152
	580	0.83054
	710	0.76863
	720	0.75675
	815	0.70693
	850	0.67474
	965	0.62133
	1015	0.60006
	1075	0.57428
	1100	0.53267
	1190	0.51314

By substituting the measured value into the formula 1 and then dividing the difference between the maximum temperature and the temperature of external fluid by the heat amount applied to the heat sink 10, thermal resistance is measured, there is given:
$R = \frac{(T_{\max} - T_{bnin})}{Q} (where Q = Q_{heater} - Q_{loss})$
The following graph shows the deducted results.
As well known in the above, we found that the temperature becomes dramatically reduced as the RPM of the heat sink 10 is increased. In this case, we proved excellent cooling efficiency of the heat sink 10.
While this invention has been particularly shown and described with reference to an exemplary embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A heat sink comprising:

a heat dissipation plate forming a channel between each of stages by isolating a plurality of heat dissipating fins in equal intervals and arranging the heat dissipating fins in a multi-stage circle shape, forming a path between the sequentially isolated heat dissipating fins at each of the stages; and

a centrifugal fan alternatively blocking the channel and path at each of the stages through a rotation by a plurality of blades arranged in a multi-stage circle shape to be positioned between the channels, inflowing outer air to discharge the air by generating a pressure difference of inter/outer air through a combination of the blade and the heat dissipation plate.

2. The heat sink of claim 1, wherein the heat dissipation plate includes a second flange in which the heat dissipation fins are mounted vertically upward with respect to the second flange, and a motor is set vertically upward on an upper surface of the second flange.

3. The heat sink of claim 2, wherein the centrifugal fan prepares a first flange in which the blades are mounted vertically downward with respect to the blade to form an inflow hole and is rendered to be rotated by fixing a rotary shaft of the motor by a connection hole of a combination block after positioning the combination block supported by a rib at a center of the inflow hole.

4. The heat sink of claim 1, wherein the path is a space between the sequentially isolated heat dissipation fins at equal intervals and has a virtual arc shape which is radiated outwardly from a center of the second flange under the condition that the heat dissipation fins are arranged in a multi-stage concentric circle shape.

5. The heat sink of claim 1, wherein the blades are arranged to be crossed between the channels and paths of each of stages in the heat dissipation plate.

6. The heat sink of claim 1, wherein the heat dissipation fins and blades have an incline line on one side thereof, and the incline lines has an angle inside from outside thereof toward a rotational direction of the heat dissipation plate.