US20110168358A1

US20110168358A1 - Lap-joined heat pipe structure and thermal module using same

Info

Publication number: US20110168358A1
Application number: US12/687,100
Authority: US
Inventors: Chun-Ming Wu
Original assignee: Asia Vital Components Co Ltd
Current assignee: Asia Vital Components Co Ltd
Priority date: 2010-01-13
Filing date: 2010-01-13
Publication date: 2011-07-14

Abstract

A lap-joined heat pipe structure includes at least one first heat pipe having at least a first heat absorbing section in contact with a heat source and at least a first heat transfer section; and at least one second heat pipe having at least a second heat absorbing section in contact with and connected to the first heat transfer section and at least a second heat transfer section. The second heat transfer section is connected to a heat dissipation unit, so that a thermal module using the lap-joined heat pipe structure is formed. The first and the second heat pipe are connected to each other at the first heat transfer section and the second heat absorbing section, which are lap-joined to each other. With the lap-joined heat pipe structure, heat transfer efficiency can be largely increased and only a reduced heat dissipation space is needed.

Description

FIELD OF THE INVENTION

The present invention relates to a lap-joined heat pipe structure and a thermal module using the same; and more particularly, to a lap-joined heat pipe structure and a thermal module using the same that enables upgraded heat transfer efficiency of the heat pipe and requires only reduced heat dissipation space.

BACKGROUND OF THE INVENTION

With the rapid development in the information, communication and photoelectric industries, all kinds of electronic devices have advanced and compact designs. On the other hand, to meet the requirements for highly quick operating speed, high working frequency, and miniaturization in size, the electronic devices now have higher and higher heating density. Therefore, heat dissipating efficiency has become an important factor in deciding the stability of electronic devices. Since the heat pipe and thermal pad have the property of high heat transfer efficiency, they have become the heat transfer elements most widely applied in electronic devices.
The heat pipe and thermal pad are mainly a sealed vacuum copper pipe or plate internally provided on inner wall surfaces with a wick structure to exert a capillary pressure. The heat pipe or thermal pad has an evaporator section, at where a working fluid filled in the heat pipe or thermal pad absorbs heat from a heat source, such as a central processing unit (CPU), and is vaporized. The vapor flows from the evaporator section to a condenser section of the heat pipe or thermal pad and is cooled thereat by, for example, radiating fins and fans, to condense into liquid, which flows back to the evaporator section under the capillary pressure of the wick structure to complete a closed recirculation in the heat pipe or the thermal pad.
Conventionally, when a relatively long heat transfer distance exists between the heat source of the electronic device and a thermal module, a heat pipe with a large diameter is selected for use in order to meet required heat transfer efficiency. However, as having been mentioned above, the current electronic devices are usually miniaturized in design to thereby have very limited internal receiving space. It might be uneasy to receive the large-diameter heat pipe in the limited internal space of the electronic device and accordingly, causes difficulty in the layout of different mechanisms in the electronic device. Further, when the heat pipe transfers heat to a relatively distant location, the heat transfer power would become weak due to an excessive length or too many bends or a relatively thin wall thickness of the heat pipe. As a result, the heat transfer performance of the heat pipe is largely reduced.
In brief, the conventional heat pipe for electronic devices has the following disadvantages: (1) having low heat transfer efficiency; (2) being limited by available heat dissipation space in the electronic devices; (3) having low flexibility in adaptation to the mechanism layout in the electronic devices and having restricted usability; (4) failing to enable further slimmed electronic devices; (5) providing low heat transfer power; and (6) having high bad yield.
It is therefore tried by the inventor to develop an improved heat pipe structure to eliminate the disadvantages in the conventional heat pipe or thermal pad.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a lap-joined heat pipe structure and a thermal module using the same, so as to upgrade the heat transfer efficiency of heat pipes.
Another object of the present invention is to provide a lap-joined heat pipe structure and a thermal module using the same, so as to save the space needed for heat dissipation.
To achieve the above and other objects, the lap-joined heat pipe structure according to the present invention includes at least one first heat pipe and at least one second heat pipe. The first heat pipe has at least a first heat absorbing section in contact with a heat source and at least a first heat transfer section. The second heat pipe has at least a second heat absorbing section in contact with and connected to the first heat transfer section and at least a second heat transfer section. The second heat transfer section is connected to a heat dissipation unit, so that a thermal module using the lap-joined heat pipe structure is formed. The first and the second heat pipe are connected to each other at the first heat transfer section and the second heat absorbing section, which are lap-joined to each other. With the lap-joined heat pipe structure, the space needed for heat dissipation via the heat pipes can be effectively reduced, and the heat transfer efficiency of the heat pipes can be largely increased.
In brief, the present invention provides the following advantages: (1) largely upgraded heat transfer efficiency; (2) effectively reduced space needed for heat dissipation; (3) effectively slimmed heat sink; (4) allowing flexible and varying mechanism layout in electronic devices; and (5) effectively increased productivity and good yield of heat pipes.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

FIG. 1 is an assembled perspective view of a thermal module using lap-joined heat pipe structure according to a first embodiment of the present invention;

FIG. 2 is an assembled perspective view of a thermal module using lap-joined heat pipe structure according to a second embodiment of the present invention;

FIG. 2 a is a fragmentary and enlarged front view showing a lap joint of a first and a second heat pipe of the lap-joined heat pipe structure for the thermal modules of FIGS. 1 and 2;

FIG. 3 is an assembled perspective view of a thermal module using lap-joined heat pipe structure according to a third embodiment of the present invention; and

FIG. 3 a is a fragmentary and enlarged front view showing a lap joint of a first and a second heat pipe of the lap-joined heat pipe structure for the thermal module of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described with some embodiments thereof. For the purpose of easy to understand, elements that are the same in the embodiments are denoted by the same reference numerals.
Please refer to FIG. 1 that is an assembled perspective view of a thermal module using lap-joined heat pipe structure according to a first embodiment of the present invention. The thermal module is generally denoted by reference numeral 1 herein. As shown, the thermal module 1 in the first embodiment includes a first heat pipe 11, a second heat pipe 12, and at least one heat dissipation unit 13.
In the illustrated first embodiment, the heat dissipation unit 13 is a heat sink and includes a heat receiving portion 131 and a heat radiating portion 132. And, the heat radiating portion 132 includes a plurality of radiating fins 1321.
Please also refer to FIG. 2 that is an assembled perspective view of a thermal module using lap-joined heat pipe structure according to a second embodiment of the present invention. The second embodiment is generally structurally similar to the first embodiment, except that the heat dissipation unit 13 thereof is a radiating fin assembly formed from a plurality of sequentially stacked radiating fins 1321.
In the first embodiment, the radiating fins 1321 are extended from the heat receiving portion 131 in a direction opposite to the heat receiving portion 131.
In the second embodiment, the radiating fins 1321 each include a first flange 1321 a and a second flange 1321 b corresponding to the first flange 1321 a.
In both the first and the second embodiment, the first heat pipe 11 includes at least a first heat absorbing section 111 and at least a first heat transfer section 112. The first heat absorbing section 111 is in contact with at least one heat source 2.
In both the first and the second embodiment, the second heat pipe 12 includes at least a second heat absorbing section 121 and at least a second heat transfer section 122. The second heat absorbing section 121 is in contact with and connected to the first heat transfer section 112. In the first embodiment, the second heat transfer section 122 is connected to the heat receiving portion 131 of the heat dissipation unit 13. And, in the second embodiment, the second heat transfer section 122 is connected to the radiating fins 1321 of the heat dissipation unit 13.
Please refer to FIG. 2 a. In both the first and the second embodiment, the first heat transfer section 112 of the first heat pipe 11 is provided with a first flat area 1121, and the second heat absorbing section 121 of the second heat pipe 12 is provided at one side facing toward the first heat transfer section 112 with a second flat area 1211. The first flat area 1121 of the first heat transfer section 112 and the second flat area 1211 of the second heat absorbing section 121 are flatly attached to each other to form a lap joint thereat. That is, the first heat pipe 11 and the second heat pipe 12 are lap-joined at the first and the second flat area 1121, 1211. Further, a heat conductive medium 3, such as thermal grease, thermal adhesive, thermal pad, or tin solder, is applied between the second heat absorbing section 121 and the first heat transfer section 112 to avoid thermal resistance caused by voids therebetween. Moreover, to enhance the binding strength therebetween, the first and the second heat pipe 11, 12 can be connected to each other by welding, clamp coupling, snap fitting, or adhesive bonding.
The second heat transfer section 122 of the second heat pipe 12 is connected to the heat dissipation unit 13 by welding, tight fitting or buckling.
As can be seen from FIGS. 1 and 2, heat produced at the heat source 2 can be transferred from the heat source via the first heat pipe 11 and the second heat pipe 12 to a remote location to dissipate therefrom. More specifically, the heat produced by the heat source 2 is absorbed by the first heat absorbing section 111 at one end of the first heat pipe 11 and then transferred to the first heat transfer section 112 located at an opposite end of the heat pipe 11. Since the first heat transfer section 112 of the first heat pipe 11 is connected to the second heat absorbing section 121 of the second heat pipe 12 via the lap joint between the first and the second heat pipe 11, 12, the heat transferred to the first heat transfer section 112 is further transferred to the second heat absorbing section 121, from where the heat is further transferred to the second heat transfer section 122 of the second heat pipe 12. As having been mentioned above, the second heat transfer section 122 is connected to the heat dissipation unit 13 that provides a relatively large heat radiating area, allowing the heat transferred from the second heat transfer section 122 to the heat dissipation unit 13 to quickly dissipate into ambient environment.
Please refer to FIG. 3 that is an assembled perspective view of a thermal module using lap-joined heat pipe structure according to a third embodiment of the present invention, and to FIG. 3 a that is a fragmentary and enlarged view showing a lap joint of the heat pipe structure. As shown, the thermal module 1 in the third embodiment includes at least one heat pipe 11, at least one second heat pipe 12, and a heat dissipation unit 13. The first heat pipe 11 includes a first heat absorbing section 111, a first heat transfer section 112, and a third heat absorbing section 113. The first and the third heat absorbing section 111, 113 are separately connected to two opposite ends of the first heat transfer section 112, and are respectively in contact with and connected to at least a heat source 2. The second heat absorbing section 121 of the second heat pipe 12 is in contact with and lap-joined to the first heat transfer section 112 of the first heat pipe 11. A heat conductive medium 3 is applied between the lap-joined second heat absorbing section 121 and the first heat transfer section 112. To ensure a firm connection therebetween, the second heat absorbing section 121 and the first heat transfer section 112 are further connected to each other by welding, clamp coupling, snap fitting, or adhesive bonding. The second heat transfer section 122 of the second heat pipe 12 is connected to the heat dissipation unit 13, which can be a heat sink or a radiating fin assembly. In the illustrated third embodiment, the heat dissipation unit 13 is a radiating fin assembly. However, it is understood the heat dissipation unit 13 is not restricted to the radiating fin assembly but can be other functionally equivalent heat dissipating structure.
Heat produced by the heat sources 2 is absorbed by the first heat absorbing section 111 and the third heat absorbing section 113 of the first heat pipe 11 and transferred to the first heat transfer section 112. With the first heat transfer section 112 being lap-joined to the second heat absorbing section 121, the heat is further transferred from the first heat transfer section 112 to the second heat absorbing section 121, and then further transferred via the second heat pipe 12 to the second heat transfer section 122. Finally, the heat is transferred from the second heat transfer section 122 to the heat dissipation unit 13, from where the heat is dissipated into ambient environment.
The present invention has been described with some preferred embodiments thereof and it is understood that many changes and modifications in the described embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.

Claims

1. A lap-joined heat pipe structure, comprising:

at least one first heat pipe including at least a first heat absorbing section and at least a first heat transfer section; the first heat absorbing section being in contact with at least a heat source; and

at least one second heat pipe including at least a second heat absorbing section and at least a second heat transfer section; the second heat absorbing section being in contact with and connected to the first heat transfer section, and the second heat transfer section being connected to a heat dissipation unit.

2. The lap-joined heat pipe structure as claimed in claim 1, wherein the first heat transfer section of the first heat pipe is formed with a flat area, and the second heat absorbing section of the second heat pipe is correspondingly provided on a side facing toward the first heat transfer section with a flat area; and the first and the second heat pipe are lap-joined to each other at the flat area of the first heat transfer section and the flat area of the second heat absorbing section.

3. The lap-joined heat pipe structure as claimed in claim 1, further comprising a thermal conductive medium applied between the second heat absorbing section and the first heat transfer section.

4. The lap-joined heat pipe structure as claimed in claim 1, wherein the first heat pipe and the second heat pipe are fixedly connected to each other in a manner selected from the group consisting of welding, clamp coupling, snap fitting, and adhesive bonding.

5. The lap-joined heat pipe structure as claimed in claim 1, wherein the heat dissipation unit is a heat sink.

6. The lap-joined heat pipe structure as claimed in claim 1, wherein the heat dissipation unit is a radiating fin assembly.

7. The lap-joined heat pipe structure as claimed in claim 3, wherein the thermal conductive medium is selected from the group consisting of thermal grease, thermal adhesive, thermal pad, and tin solder.

8. A thermal module using lap-joined heat pipe structure, comprising:

at least one heat dissipation unit having a heat receiving portion and a heat radiating portion, the heat radiating portion including a plurality of radiating fins;

a first heat pipe including at least a first heat absorbing section and at least a first heat transfer section; the first heat absorbing section being in contact with at least a heat source; and

a second heat pipe including at least a second heat absorbing section and at least a second heat transfer section; the second heat absorbing section being in contact with and lap-joined to the first heat transfer section, and the second heat transfer section being connected to the heat receiving portion of the heat dissipation unit.