US20100025013A1

US20100025013A1 - Heat dissipation device

Info

Publication number: US20100025013A1
Application number: US12/326,112
Authority: US
Inventors: Xin-Xiang Zha
Original assignee: Fuzhun Precision Industry Shenzhen Co Ltd; Foxconn Technology Co Ltd
Current assignee: Fuzhun Precision Industry Shenzhen Co Ltd; Foxconn Technology Co Ltd
Priority date: 2008-07-31
Filing date: 2008-12-02
Publication date: 2010-02-04
Also published as: CN101641005B; CN101641005A

Abstract

An exemplary heat dissipation device includes a plurality of parallel fins, a heat pipe extending through the fins, and a guiding structure formed on each of the fins. An airflow channel is formed between every two neighboring fins for an airflow flowing therethough. The guiding structure is formed for guiding the airflow to flow to the heat pipe. A space is defined within the guiding structure and has a width decreasing gradually along a flowing direction of the airflow. An opening is defined in the guiding structure for communicating airflow at two opposite sides of each fin. A height of the guiding structure decreases gradually from the opening towards other sides of the guiding structure.

Description

BACKGROUND

1. Technical Field
The disclosure relates to heat dissipation devices, and particularly to a heat dissipation device with improved fin structure for achieving a high heat-dissipation efficiency.
2. Description of related art
With the advance of large scale integrated circuit technology, and the wide spread of use of computers in all trades and occupations, in order to meet the required improvement in data processing load and request-response times, high speed processors have become faster and faster, which causes the processors to generate redundant heat. Redundant heat which is not quickly removed will have tremendous influence on the system security and performance. Usually, people install a heat sink on the central processor to assist its heat dissipation, whilst also installing a fan on the heat sink, to provide a forced airflow to increase the heat dissipation.
FIG. 8 shows a conventional heat dissipation device 1. The heat dissipation device 1 includes a fin unit 2, a heat pipe 4 extending through the fin unit 2, and a cooling fan (not shown) arranged at a side of the fin unit 2 so as to generate an airflow towards the fin unit 2. The fin unit 2 includes a plurality of fins stacked together. Each fin is planar and parallel to each other. A flow channel 3 is formed between two adjacent fins. The heat pipe 4 includes an evaporating section for thermally connecting with a heat-generating component and condensing sections extending into through holes of the fin unit 2 and thermally connecting with the fins.
During operation of the heat-generating component, the heat pipe 4 absorbs heat generated by the heat-generating component. The heat is transferred from the evaporating section to the condensing sections and then on to the fins of the fin unit 2. At the same time, the airflow generated by the cooling fan flows through the flow channels 3 to exchange heat with the fins. The heat is dissipated to the surrounding environment by the airflow. Thus, heat dissipation of the heat-generating component is accomplished.
For enhancing the heat dissipation effectiveness of this heat dissipation device 1, the heat dissipation area of the fin unit 2 needs to be increased. One way to increase the heat dissipation area of the fin unit 2 is to accommodate more fins or to increase the size of each fin. However, this increases the weight of the heat dissipation device 1, which conflicts with the requirement for light weight and compactness. Another way to increase the heat dissipation area of the fin unit 2 is reducing the spacing distance of two adjacent fins, so that the fin unit 2 can accommodate more fins. This way may avoid increasing the volume of heat dissipation device 1; however, reducing the spacing between two adjacent fins of the fin unit 2 will increase the flow resistance, which not only influences the heat dissipation effect but also increases the noise. Also, due to the planar shape of each fin of the fin unit 2, the airflow flows evenly through every part of the fin. However, such an even airflow distribution on the fin cannot effectively take heat from the fin which usually is concentrated at a particular portion of the fin. Thus, the airflow of the conventional heat dissipation device 1 cannot effectively dissipate the heat in the fins of the fin unit 2. Therefore, the airflow flowing through the fin unit 2 cannot sufficiently assist the heat dissipation of the heat-generating component. Furthermore, due to the influence of viscosity, a laminar air envelope may form at lateral sides of each fin, when the airflow flows through the fin unit 2. The flowing speed of the airflow in the laminar envelope is nearly zero; in the laminar envelope, the main way of heat dissipation of the fins is by heat radiation and the heat exchange effect between the fin unit 2 and the airflow is thus greatly reduced. Accordingly, the heat dissipation effectiveness of the conventional heat dissipation device 1 is limited.
It is thus desirable to provide a heat dissipation device which can overcome the described limitations.

SUMMARY

The present invention relates to a heat dissipation device. According to an exemplary embodiment of the present invention, the heat dissipation device includes a plurality of parallel fins, a heat pipe extending through the fins, and a guiding structure. An airflow channel is formed between every two neighboring fins for an airflow flowing therethough. The guiding structure is formed on each of the fins for guiding the airflow flowing to the heat pipe. A space is defined between the guiding structure and has a width decreasing gradually along a flowing direction of the airflow. At least one opening is defined in the guiding structure for communicating airflow at two opposite sides of each fin. A height of the guiding structure decreases gradually from the at least one opening towards other sides of the guiding structure.
Other advantages and novel features of the present invention will become more apparent from the following detailed description of embodiment when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an assembled, isometric view of a heat dissipation device in accordance with a first embodiment.

FIG. 2 is an isometric view of a fin of the heat dissipation device of FIG. 1.

FIG. 3 is a view similar to FIG. 2, but shown from a different aspect.

FIG. 4 is an isometric view of a fin in accordance with a second embodiment.

FIG. 5 is a view similar to FIG. 4, but shown from a different aspect.

FIG. 6 is an isometric view of a fin in accordance with a third embodiment.

FIG. 7 is a view similar to FIG. 6, but shown from a different aspect.

FIG. 8 is a side view of a conventional heat dissipation device.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made to the drawings to describe the various embodiments in detail.
Referring to FIG. 1, a heat dissipation device according to a first embodiment includes a heat sink 10 and a heat pipe 12. The heat pipe 12 includes an evaporation section 121 thermally contacting with an electronic component 14 and a condenser section 122 extending through a central portion of the heat sink 10. The evaporation section 121 absorbs heat generated by the electronic component 14. The heat is transferred from the evaporation section 121 to the condenser section 122, and then on to the heat sink 10. A cooling fan (not shown) is arranged at one side (i.e., right side of this embodiment) of the heat sink 10 for generating an airflow towards the heat sink 10 as indicated by arrows F.
The heat sink 10 includes a plurality of fins 11 arranged side by side and parallel to each other. Referring to FIG. 2 and FIG. 3, each of the fins 11 includes a rectangular main body 110 which has a reference surface 1101 and a base surface 1102. A flow channel 13 is formed between every two neighboring fins 11 to channel the airflow generated by the fan. A through hole 1104 is defined in each of the main body 110 of the fins 11 for receiving the condenser section 122 of the heat pipe 12. The shape and size of the through hole 1104 can change according to the heat pipe 12. A circular flange 1105 extends outwardly from a border of the through hole 1104 of the reference surface 1101 of each fin 11 towards the base surface 1102 of an adjacent fin 11, and a length of the flange 1105 is nearly equal to a distance between the two adjacent fins 11. When the heat sink 10 is assembled together, the flanges 1105 of each fin 11 contact the border of the through hole 1104 of the base surface 1102 of the adjacent fin 11. Thus, the through holes 1104 cooperatively form a columned space for the heat pipe 12 extending through, and the flanges 1105 enclose and contact with the heat pipe 12, which enlarges the contacting surface area between the heat pipe 12 and the fins 11. So, heat absorbed by the heat pipe 12 can be quickly transferred to the fins 11 for further dissipation.
A guiding structure 113 includes two spaced first and second guiding members 1131, 1132 located adjacent the through hole 1104 and protruding from the reference surface 1101 of each fin 11. Two concave hollows 1151, 1152 corresponding to the two guiding members 1131, 1132 are formed in the base surface 1102 of the fin 11. The first guiding member 1131 and the second guiding member 1132 locate at a top side and a bottom side of the through hole 1104, respectively. The first and second guiding members 1131, 1132 are substantially symmetric to a horizontal axis X-X (FIG. 3) which extends through a center of the through hole 1104 of the fin 11. Each of the first guiding member 1131 and the second guiding member 1132 is substantially straight, and extends aslant from a position adjacent to the flange 1105 towards a corner of the main body 110, i.e., the first guiding member 1131 extending upward and rightward towards a top corner located at a right side of the fin 11 adjacent to the fan, the second guiding member 1132 extending downward and rightward towards a bottom corner located at the right side of the fin 11 adjacent to the fan. A distance between the first guiding member 1131 and the axis X-X decreases gradually along the direction of the airflow (as indicated by the arrows F). Similarly, a distance between the second guiding member 1132 and the axis X-X also decreases gradually along the direction of the airflow. Thus, the first guiding member 1131 and the second guiding member 1132 cooperatively define a tapered space 1133 therebetween.
The first guiding member 1131 and the second guiding member 1132 cooperatively form a converged side 114 adjacent to the flange 1105 and a diverged side 118 facing the airflow. The airflow flows into the tapered space 1133 via the diverged side 118 of the guiding members 1131, 1132. The first guiding member 1131 and the second guiding member 1132 guide the airflow towards the converged side 114. Thus, the airflow is concentrated at the area of each fin 11 near to the heat pipe 12. That is, the airflow first flows through the diverged side 118 of the guiding members 1131, 1132, then the converged side 114 and finally the heat pipe 12.
Each of the first and second guiding members 1131, 1132 includes a linear inner side 116 facing the space 1133 and an opposite curved outer side 117 away from the space 1133. The inner sides 116 of the guiding members 1131, 1132 extend aslant along the main body 110 and face the airflow to guide the airflow to the flange 1105 and the through hole 1104. The inner sides 116 function as windward sides of the guiding members 1131, 1132. The outer side 117 is about C-shaped and smoothly connects with the main body 110 of each fin 11. Each of the first and second guiding members 1131, 1132 defines an opening 112 in the inner side 116 for communicating with the space 1131. Airflow channels 13 at opposite sides of each fin 11 communicate with each other via the openings 112. A height of each of the guiding members 1131, 1132 decrease from the inner side 116 towards the outer side 117. A maximal height of each of the guiding members 1131, 1132 is smaller than the distance between two adjacent fins 11. When the heat sink 10 is assembled together, the guiding members 1131, 1132 are spaced from the adjacent fin 11. In this embodiment, the maximal height of each of the guiding members 1131, 1132 equals to a half of the distance between two adjacent fins 11, and an outmost surface of each of the guiding members 1131, 1132 is located at a middle of the airflow channel 13 between the two adjacent fins 11.
During operation of the heat dissipation device, the evaporation section 121 of the heat pipe 12 absorbs heat generated by the heat-generating component 14. Working fluid contained in the heat pipe 12 absorbs heat and evaporates substantially and moves to the condenser section 122. Evaporated working fluid at the condenser section 122 releases the heat to the fins 11 and thus is condensed. Finally, the condensed working fluid flows back to the evaporation section 121 to begin another cycle. By this way, the working fluid absorbs/releases amounts of heat. The heat generated by the heat-generating component 14 is thus transferred by the heat pipe 12 to the fins 11 almost immediately.
As the fins 11 are likely to have significant heat resistance, a hot area is formed around the through holes 1104, which is adjacent to condenser section 122 of the heat pipe 12 in the fins 11. The temperature in this hot area is higher compared to the rest of the fins 11. After the forced airflow generated by the fan flows into the airflow channel 13, the first guiding member 1131 and the second guiding member 1132 guide a part of the airflow, which is closer to the reference surface 1101 of each fin 11, to flow to the hot area around the heat pipe 12. Thus, the heat in this area can be efficiently carried away by the portion of airflow. Width of the space 1133 formed between the first guiding member 1131 and the second guiding member 1132 decreases gradually along the direction of the airflow, which results in the speed of the airflow being increased to thereby increasing heat dissipation efficiency of the heat sink 10. Due to the influence of viscosity, a laminar air envelope will be formed on the reference surface 1101 of each fin 11, when the airflow passes through the flow channel 13, but if the airflow meets a barrier during its flowing process, a vortex is formed around the barrier. The guiding members 1131, 1132 act as a barrier arranged in the airflow channel 13, which cause the airflow to form turbulences, thereby destroying the laminar air envelope possibly formed on the reference surface 1101 of each fin 11. The other part of the airflow, which is closer to the base surface 1102 of each fin 11, passes through the airflow channel 13 near the base surface 1102. Arrangement of the concave hollows 1151, 1152, which function as the guiding members 1131, 1132, causes the other part of the airflow to generate turbulences, thereby to prevent the possible laminar air envelop from forming on the base surface 1102. Heat exchange effect between the airflow and the fins 11 is therefore improved. The heat dissipation efficiency of the heat sink 10 is thus increased. The concave hollows 1151, 1152 are formed when the fin 11 is stamped to form the first and second guiding members 1131, 1132.
FIG. 4 and FIG. 5 illustrate a fin 11 a in accordance with an alternative embodiment. The difference of the second embodiment over the first embodiment is that the first and the second guiding members 1131 a, 1132 a are curved, and surround a part of the through hole 1104. Two concave hollows 1151 a, 1152 a corresponding to the two guiding members 1131 a, 1132 a are formed in the base surface 1102 of the fin 11 a. Each of the first and second guiding members 1131 a, 1132 a includes an curved inner side 116 a facing the space 1133 a, an opposite curved outer side 117 a away from the space 1133 a, a linear windward side 111 interconnected between ends of the inner side 116 a and the outer side 117 a adjacent to the fan, and a linear leeward side 119 interconnected between ends of the inner side 116 a and the outer side 117 a away from the fan. A distance between the inner sides 116 a of the first and the second guiding members 1131 a, 1132 a decreases from the windward sides 111 towards the leeward sides 119. The height of each of the first and the second guiding members 1131 a, 1132 a also decreases from the windward side 111 towards the leeward side 119. The leeward sides 119 of the first and the second guiding members 1131 a, 1132 a connect smoothly with the main body 110 of each fin 11 a. An opening 112 a is defined in the windward side 111 of each of the first and the second guiding members 1131 a, 1132 a and faces the airflow. Airflow channels 13 at opposite sides of each fin 11 communicate with each other via the openings 112 a.
The first guiding member 1131 a and the second guiding member 1132 a cooperatively form a converged side 114 a in rear of the flange 1105 and a diverged side 118 a facing the airflow. The airflow first flows through the diverged sides 118 a of the guiding members 1131 a, 1132 a, then the heat pipe 12 and finally the converged sides 114 a. That is, the first guiding member 1131 a and the second guiding member 1132 a are capable of guiding the airflow to flow to and concentrate at the area near the heat pipe 12 in each fin 11 a. When the airflow flows through the space 1133 a, the airflow is concentrated. The concentrated airflow with a higher speed flows through the flanges 1105 to take the heat away from condenser section 122 the heat pipe 12 timely.
FIG. 6 and FIG. 7 illustrate a fin 11 b in accordance with another alternative embodiment. The difference of the third embodiment over the second embodiment is that the first guiding member 1131 a and the second guiding member 1132 a are integrated together at the leeward sides 119 of the second embodiment to form an integral guiding structure 113 b of the third embodiment. A concave hollow 115 b corresponding to the guiding structure 113 b is formed in the base surface 1102 of each fin 11 b. The guiding structure 113 b is generally arc-shaped, and includes a middle portion 1131 b and two sloping side portions 1132 b extending forwardly from the middle portion 1131 b. The middle portion 1131 b is curved and forms a converged side 114 b in rear of the heat pipe 12. The two sloping side portions 1132 b each including a linear windward side 111 b facing the airflow. A diverged side 118 b is defined between the windward sides 11 lb. Two openings 112 b are defined in the windward sides 111 b of the sloping side portions 1132 b respectively. The height of the guiding structure 113 b decreases gradually from the windward sides 111 b of the sloping side portions 1132 b towards the middle portion 1131 a.
It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

Claims

1. A heat dissipation device comprising:

a plurality of parallel fins with an airflow channel formed between every two neighboring fins for an airflow flowing therethough;

a heat pipe extending through the fins; and

a guiding structure being formed on each of the fins for guiding the airflow flowing to the heat pipe, a space being defined within the guiding structure and having a width decreasing gradually along a flowing direction of the airflow, at least one opening being defined in the guiding structure for communicating airflow at two opposite sides of each fin, a height of the guiding structure decreasing gradually from the at least one opening towards other sides of the guiding structure.

2. The heat dissipation device of claim 1, wherein the guiding structure comprises two guiding members protruding from a reference surface of each fin, the two guiding members arranged symmetrically to the heat pipe.

3. The heat dissipation device of claim 2, wherein each of the guiding members comprises a linear inner side facing the space and an opposite curved outer side, the at least one opening having two in number, the openings being defined in the inner sides of the two guiding members respectively, the height of each guiding member with respect to the reference surface of the each fin decreasing gradually from the inner side towards the outer side.

4. The heat dissipation device of claim 3, wherein the outer sides of the guiding members smoothly connect with the reference surface of each fin.

5. The heat dissipation device of claim 3, wherein the guiding members cooperatively form a converged side adjacent to the heat pipe and a diverged side facing the airflow, the airflow flowing first into the space via the diverged side, then being guided towards the converged side, and finally being concentrated at an area of each fin near to the heat pipe.

6. The heat dissipation device of claim 2, wherein each of the guiding members comprises a curved inner side facing the space, an opposite curved outer side away from the space, a windward side interconnected between ends of the inner side and the outer side facing the airflow, and a leeward side interconnected between ends of the inner side and the outer side away from the airflow, the at least one opening having two in number, the openings being defined in the windward sides of the guiding members respectively.

7. The heat dissipation device of claim 6, wherein the height of each guiding member with respect to the reference surface of each fin decreases gradually from the windward side towards the leeward side.

8. The heat dissipation device of claim 7, wherein the leeward sides of the guiding members smoothly connect with the reference surface of each fin.

9. The heat dissipation device of claim 6, wherein the guiding members cooperatively form a diverged side facing the airflow and a converged side in rear of the heat pipe, and the airflow flows into the space via the diverged side and then is concentrated at the converged side after flowing through the heat pipe.

10. The heat dissipation device of claim 1, wherein the guiding structure comprises a middle portion and two sloping side portions extending from the middle portion, and the middle portion is curved and forms a converged side in rear of the heat pipe, the two sloping side portions each comprising a linear windward side facing the airflow, the at least one opening having two in number, the openings being defined in the windward sides of the sloping side portions, respectively, a diverged side being formed between the linear windward sides of the sloping side portions.

11. The heat dissipation device of claim 10, wherein the guiding structure protrudes from a reference surface of each fin, the height of the guiding structure decreasing gradually from the windward sides of the sloping side portions towards the middle portion.

12. A heat dissipation device comprising:

a plurality of fins arranged side by side, each fin defining a hole, a flange extending from a reference surface of the each fin around the hole, an airflow channel being formed between every two neighboring fins for an airflow flowing therethough;

a heat pipe extending through the hole and thermally connecting with the flange; and

two guiding members protruding from the reference surface for guiding the airflow flowing to the heat pipe, a space being defined between the two guiding members and having a width decreasing gradually along a flowing direction of the airflow, each of the guiding members comprising a linear windward side facing the airflow, two openings being defined in the windward sides of the two guiding members respectively, the openings being configured for communicating the airflow at two opposite sides of each fin.

13. The heat dissipation device of claim 12, wherein the two guiding members are arranged symmetrically to the heat pipe, each of the guiding members comprising a linear inner side functioning as the windward side and an opposite curved outer side, the openings being defined in the inner sides of the two guiding members respectively, a height of each guiding member decreasing gradually from the inner side towards the outer side.

14. The heat dissipation device of claim 12, wherein the two guiding members are arranged symmetrically to the heat pipe, each of the guiding members comprising a curved inner side facing the space, an opposite curved outer side away from the space, the windward side interconnected between ends of the inner side and the outer side facing the airflow, and a leeward side interconnected between ends of the inner side and the outer side away from the airflow, a height of each guiding member decreasing gradually from the windward side towards the leeward side.