U.S. patent application number 09/998706 was filed with the patent office on 2003-06-05 for cooling system for electronics with improved thermal interface.
Invention is credited to DeHoff, Robert E., Hartenstine, John, Sarraf, David B., Todd, John J. JR..
Application Number | 20030102108 09/998706 |
Document ID | / |
Family ID | 25545491 |
Filed Date | 2003-06-05 |
United States Patent
Application |
20030102108 |
Kind Code |
A1 |
Sarraf, David B. ; et
al. |
June 5, 2003 |
Cooling system for electronics with improved thermal interface
Abstract
A heat pipe system including a heat transfer block and a heat
pipe coupled to the heat transfer block by a clip. By utilizing a
clip to couple the heat pipe to the heat transfer block, a higher
degree of thermal coupling may be achieved, thereby allowing more
heat to be transferred from the heat transfer block to the heat
pipe. The heat pipe system has particular application in
transferring heat away from heat-producing electronic components,
such as computer chips.
Inventors: |
Sarraf, David B.;
(Elizabethtown, PA) ; DeHoff, Robert E.; (Mt. Joy,
PA) ; Hartenstine, John; (Landisville, PA) ;
Todd, John J. JR.; (Elizabethtown, PA) |
Correspondence
Address: |
Samuel W. Apicelli
Duane Morris LLP
P.O. Box 1003
Harrisburg
PA
17108-1003
US
|
Family ID: |
25545491 |
Appl. No.: |
09/998706 |
Filed: |
November 30, 2001 |
Current U.S.
Class: |
165/80.3 ;
165/104.33; 257/715; 257/E23.088; 361/700 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H01L 23/427 20130101; F28D 15/0283 20130101; H01L 2924/00 20130101;
H01L 2924/0002 20130101; F28D 15/0266 20130101 |
Class at
Publication: |
165/80.3 ;
165/104.33; 361/700; 257/715 |
International
Class: |
F28F 007/00; F28D
015/00; H05K 007/20; H01L 023/34 |
Claims
What is claimed is:
1. A heat pipe system comprising: a heat transfer block; and, a
heat pipe coupled to the heat transfer block by a clip.
2. The heat pipe system of claim 1, wherein the clip includes a
main surface and two side surfaces disposed substantially
orthogonal to the main surface.
3. The heat pipe system of claim 1, wherein the heat transfer block
includes at least one clip channel disposed therein for receiving
the clip.
4. The heat pipe system of claim 1, wherein the heat transfer block
includes at least two clip channels disposed therein for receiving
the clip.
5. The heat pipe system of claim 1, wherein the heat transfer block
includes at least one heat pipe channel disposed therein for
receiving the heat pipe.
6. The heat pipe system of claim 5, wherein the heat pipe includes
a main portion and a pinchoff portion, wherein the pinchoff portion
is disposed in the heat pipe channel.
7. The heat pipe system of claim 5, wherein the heat pipe is
coupled to the heat pipe channel by solder.
8. The heat pipe system of claim 5, wherein the heat pipe is
coupled to the heat pipe channel by epoxy.
9. The heat pipe system of claim 5, wherein the heat pipe is
coupled to the heat pipe channel by friction.
10. The heat pipe system of claim 5, wherein the heat pipe is
coupled to the heat pipe channel by at least one fastener.
11. The heat pipe system of claim 2, wherein the heat transfer
block includes at least one clip channel disposed therein for
receiving the clip, such that the two side surfaces of the clip are
disposed in the at least one clip channel.
12. The heat pipe system of claim 11, wherein the clip is coupled
to the at least two clip channels by solder.
13. The heat pipe system of claim 11, wherein the clip is coupled
to the at least two clip channels by epoxy.
14. The heat pipe system of claim 11, wherein the clip is coupled
to the at least two clip channels by friction.
15. The heat pipe system of claim 11, wherein the heat pipe is
coupled to the heat pipe channel by at least one fastener.
16. The heat pipe system of claim 2, wherein the heat transfer
block includes at least two clip channels disposed therein for
receiving the clip, such that the two side surfaces of the clip are
disposed in the at least two clip channels.
17. The heat pipe system of claim 16, wherein the clip is coupled
to the at least two clip channels by solder.
18. The heat pipe system of claim 16, wherein the clip is coupled
to the at least two clip channels by epoxy.
19. The heat pipe system of claim 16, wherein the clip is coupled
to the at least two clip channels by friction.
20. The heat pipe system of claim 16, wherein the heat pipe is
coupled to the heat pipe channel by at least one fastener.
21. The heat pipe system of claim 1, wherein the clip includes a
top surface and bottom surface with at least two tabs extending
orthogonally from the bottom surface.
22. The heat pipe system of claim 21, wherein the heat transfer
block includes at least two channels for receiving the at least two
tabs in the clip.
23. The heat pipe system of claim 1, wherein the clip extends
substantially across an entire top surface of the heat transfer
block.
24. A computer comprising: at least one electronic component; a
heat transfer block disposed adjacent to the at least one
electronic component; and, a heat pipe coupled to the heat transfer
block by a clip.
25. A method for cooling a heat-producing element, comprising the
steps of: disposing a heat transfer block adjacent the
heat-producing element; coupling the heat transfer block to a heat
pipe using a clip.
26. A method for manufacturing a heat pipe assembly, comprising the
steps of: forming a heat transfer block with at least one heat pipe
channel and at least one clip channel disposed therein; bonding a
heat pipe to the heat pipe channel; and bonding a clip to the at
least one clip channel, such that the clip overlies at least a
portion of the heat pipe.
27. The method of claim 26, wherein the steps of bonding the heat
pipe and bonding the clip comprise bonding by solder.
28. The method of claim 26, wherein the steps of bonding the heat
pipe and bonding the clip comprise bonding by epoxy.
29. The method of claim 26, wherein the steps of bonding the heat
pipe and bonding the clip comprise bonding by fasteners.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a method and apparatus for
a heat pipe system for removing heat from electronic equipment, and
in particular, a heat pipe system for removing heat from a laptop
computer.
DESCRIPTION OF THE RELATED ART
[0002] A basic heat pipe comprises a closed or sealed envelope or a
chamber containing an isotropic liquid-transporting wick and a
working fluid capable of having both a liquid phase and a vapor
phase within a desired range of operating temperatures. When one
portion of the chamber is exposed to relatively high temperature it
functions as an evaporator section. The working fluid is vaporized
in the evaporator section causing a slight pressure increase
forcing the vapor to a relatively lower temperature section of the
chamber defined as a condenser section. The vapor is condensed in
the condenser section and returned through the liquid-transporting
wick to the evaporator section by capillary pumping action.
[0003] Because it operates on the principle of phase changes rather
than on the principles of conduction or convection, a heat pipe is
theoretically capable of transferring heat at a much higher rate
than conventional heat transfer systems. Consequently, heat pipes
have been utilized to cool various types of high heat-producing
apparatus, such as electronic equipment (See, e.g., U.S. Pat. Nos.
5,884,693, 5,890,371, and 6,076,595).
[0004] Heat pipe assemblies are often used to remove heat from the
Central Processing Unit (CPU) and other high power chips in
computers. Maintenance of a good contact between the CPU (or other
chip) and the heat pipe assembly is essential for insuring good
overall heat transfer.
[0005] Some conventional heat pipe assemblies create a contact
between the CPU (or other chip) and a portion of the heat pipe
through a heat transfer plate. Such heat transfer plates are
disposed either above or below the CPU or chip, and are typically
centered on the CPU or chip by guide members on the heat transfer
plate which interface with guide members on the CPU or chip.
[0006] Most conventional heat transfer plates comprises metal
blocks with at least one tunnel or recess therein for receiving a
flattened end of the associated heat pipe. FIG. 1 shows such a
conventional heat pipe system 200. The heat pipe system 200
includes a heat transfer block 210, a heat pipe 220, and a heat
dissipation structure 230. In a typical environment, such heat pipe
system 200 would be disposed in proximity to a heat-producing
apparatus (e.g. CPU, chip, etc.), such that the heat transfer block
210 would be in direct contact with the heat-producing apparatus.
The heat transfer block 210 includes a tunnel 211 therein for
receiving a flattened portion 221 of the heat pipe 220. The heat
pipe 220 also includes a crimped end or `pinchoff` portion 222
disposed at one end of the flattened portion 221. An end of the
heat pipe 220 opposite the flattened portion 221 is coupled to the
heat dissipation structure 230 (e.g., fin block). During
manufacture of the heat pipe system shown in FIG. 1, the flattened
portion 221 of the heat pipe 220 is inserted into the tunnel 211 in
the heat transfer block 210, and is secured therein.
[0007] Since this tunnel 211 in the heat transfer block 210 must be
made large enough to receive the flattened end 221 of the heat pipe
220, and the pinchoff portion 222 of the heat pipe, the tunnel must
be made at least as wide as the pinchoff. Since the pinchoff 222 is
almost always wider than the flattened portion 221 of the heat pipe
220, the flattened portion of the heat pipe does not fit snugly in
the tunnel 211, and thus, a poor heat contact is created between
the flattened portion of the heat pipe and the heat transfer block
210. Due to the poor heat contact between the flattened portion of
the heat pipe 220 and the heat transfer block 210, maximum heat
cannot be transferred from the CPU or chip to the heat pipe through
the heat transfer plate.
[0008] Therefore, there is currently a need for a heat pipe system
for effectively transferring maximum heat from a CPU (or other
chip) to a heat pipe assembly in a computer.
SUMMARY OF THE INVENTION
[0009] The present invention is a heat pipe system including a heat
transfer block and a heat pipe coupled to the heat transfer block
by a clip.
[0010] The above and other advantages and features of the present
invention will be better understood from the following detailed
description of the exemplary embodiments of the invention which is
provided in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a perspective view showing a conventional heat
pipe system.
[0012] FIG. 2 is a perspective view showing a heat pipe system
according to a first exemplary embodiment of the present
invention.
[0013] FIG. 3 is a perspective view showing a magnified version of
the heat pipe system shown in FIG. 2.
[0014] FIG. 4 is a perspective view showing an exploded and
magnified version of the heat pipe system shown in FIG. 2.
[0015] FIG. 5 is a perspective view showing a heat pipe system
according to a second exemplary embodiment of the present
invention.
[0016] FIG. 6 is a perspective view showing an exploded version of
the heat pipe system shown in FIG. 5.
[0017] FIG. 7 is a perspective view showing a heat pipe system
according to a third exemplary embodiment of the present
invention.
[0018] FIG. 8 is a perspective view showing an enlarged of the heat
pipe system shown in FIG. 7.
DETAILED DESCRIPTION
[0019] The present invention comprises an improved apparatus and
method for transferring heat from a heat-producing electronic
equipment (e.g., CPU or other computer chip) to a heat pipe through
the use of a heat transfer plate. By attaching the heat pipe to the
heat transfer plate through a clip placed in the center of the heat
transfer plate, maximum heat transfer from the heat transfer plate
to the heat pipe can be achieved.
[0020] Referring to FIG. 2, there is shown a heat pipe system 100
according to a first exemplary embodiment of the present invention.
The heat pipe system 100 comprises a heat transfer block 110, a
heat pipe 120, and a heat dissipation structure 130.
[0021] The heat transfer block 110 includes a channel 111 therein
for receiving a flattened portion 121 of the heat pipe 120. The
heat pipe 120 also includes a pinchoff portion 122 disposed at one
end of the flattened portion 121. An end of the heat pipe 120
opposite the flattened portion 121 is coupled to the heat
dissipation structure 130 (e.g., fin block). One end of the channel
111 of the heat transfer block 110 has a flared portion 112 for
receiving the pinchoff portion 122 of the heat pipe 120. A clip
member 140 overlies and secures the flattened portion 121 of the
heat pipe 120 in the channel 111. It will be noted that the clip
member 140 includes a main surface 141, and two side surfaces 142,
143 disposed orthogonal to the main surface. The main surface 141
primarily overlies the flattened portion 121 of the heat pipe 120,
and the two side surfaces 142, 143 primarily reside in clip
channels 113, when the clip 140 is coupled to the heat transfer
block 110.
[0022] FIG. 3 shows an enlarged view of the heat pipe 120 and heat
transfer block 110 of the heat pipe system 100 according to the
first exemplary embodiment of the present invention. It will be
noted that the flattened portion 121 of the heat pipe is secured in
the channel 111 of the heat transfer block 110 by the clip member
140.
[0023] FIG. 3 explicitly shows that the two side surfaces 142, 143
of the clip are received in clip channels 113 formed in the heat
transfer block 110. It will be noted that although the clip
channels 113 are formed as channels of a specific length which is
less then the length of the transfer block 110, the clip channels
may also be formed as full-length channels, such as channel 111. As
will be understood by those skilled in the art, forming the clip
channels 113 as full-length channels may reduce the expense of
producing the heat transfer block 110 by allowing the transfer
block to be formed completely by extrusion processes. The flattened
portion 121 of the heat pipe 120 and the clip 140 may be secured in
the channel 111 and the clip channels 113 respectively by fasteners
(e.g., screws, bolts, stakes, rivets, etc.), solder, epoxy or other
known materials.
[0024] Alternatively, the flattened portion 121 of the heat pipe
120 and the clip 140 may be secured in the channel 111 and the clip
channels 113 by the surface friction of the flattened portion and
the clip 140 against the walls of the channel 111 and the clip
channels 113. In order to accomplish a tight friction contact
between the channel 111 and the flattened portion 121 of the heat
pipe 120, the channel is made only slightly wider than the
flattened portion, so that the flattened portion fits snugly in the
channels. To effect a tight friction contact between the clip 140
and the clip channels 113, the side surfaces 142, 143 of the clip
are splayed out (i.e., away from the main surface) slightly, so
that the side surfaces of the clip are urged against the clip
channel walls when the clip is disposed in the heat transfer block
110.
[0025] The heat transfer block 110 also includes guide members 114
with openings 115 formed therein for securing the heat transfer
block to a CPU or chip. Typically, a CPU or chip will include
complementary guide members, such as posts, which may be received
in the openings 115 in order to secure the heat transfer block 110
to the CPU or chip.
[0026] The above-described heat pipe system 100 may be formed by
various methods. For example, the heat transfer block 110 may be
formed as a single substantially uniform part which is later milled
to create the heat pipe channel 111 and clip channels 113. Once the
milled part has been manufactured, the heat pipe 120 and clip 140
may be bonded to the heat transfer block 110 by the methods
discussed above (e.g., solder, epoxy, friction, fasteners), or by
other means known to those skilled in the art. Alternatively, the
heat transfer block 110 may be formed with the heat pipe channel
111 and the clip channels 113 already formed therein, by a process
such as extrusion.
[0027] Since, in the present invention, the flattened portion 121
of the heat pipe 120 fits tightly within the channel 111 in the
heat transfer block 110, and is further secured using clip 140,
maximum heat transfer from the heat transfer block to the heat pipe
can be achieved. As explained above, in conventional heat pipe
systems such maximum heat transfer could not be realized due to the
fact that the flattened portion of the heat pipe did not fit snugly
within the channel (See FIG. 1). Thus, the present invention it is
submitted that the present invention represents a significant
advance in heat transfer technology.
[0028] FIG. 4 shows an enlarged and exploded view of the heat pipe
120 and heat transfer block 110 of the heat pipe system 100
according to the first exemplary embodiment of the present
invention. FIG. 4 clearly shows that the channel 111 includes a
flared portion 112 which is wider than the rest of the channel. As
stated above, this flared portion 112 operates to receive the
pinchoff portion 122 of the heat pipe 120. FIG. 4 also clearly
shows the clip channels 113. Although the clip channels 113 are
oval-shaped in FIG. 4, it will be understood that these channels
may take various geometrical shapes (e.g., rectangles, etc.).
[0029] One of the main reasons for utilizing the channel structure
111 described above is to provide a means of applying downward
pressure on the heat transfer block 110. The downward pressure must
be applied at the physical center of the CPU or chip to which the
transfer block 110 is coupled to assure that the transfer block is
seated squarely on the CPU or chip without creating a gap
therebetween. Often times when the transfer block 110 is not seated
squarely on the CPU or chip a wedge-shaped gap is formed between
the transfer block and the CPU or chip. Such a gap could result in
poor thermal contact between the CPU or chip and the transfer block
110, and could, in the case of a CPU having an exposed silicon die,
cause cracking or splaying from the edges of the die, and
subsequently reduce heat transfer area or cause electrical
malfunction. The downward pressure cannot be applied through the
wall of the heat pipe because the wall is often made of a thin
metal (e.g., Copper) sheet which does not have sufficient tensile
strength to transfer the force without deformation of the metal.
Such deformation may result in diminution of the contact pressure,
and reduction in heat pipe performance due to the local reduction
in vapor flow area. The channel structure 111 is designed to
circumvent the deformation problem, while allowing pressure to be
applied at the center of the CPU or chip to which the transfer
block 110 is coupled.
[0030] Additionally, in the first exemplary embodiment described
above, the heat pipe 120 is disposed at the physical center of the
CPU or chip, the region of maximum heat production. Location of the
heat pipe 120 in this region produces a heat pipe system 100 with a
low thermal resistance.
[0031] Referring to FIG. 5, there is shown a heat pipe system 300
according to a second exemplary embodiment of the present
invention. Similar to the heat pipe system 100, the heat pipe
system 300 includes a heat transfer block 310, a heat pipe 320, and
a heat dissipation structure (not shown). However, the heat pipe
system 300 includes only a single clip channel 313 for receiving a
clip 340.
[0032] FIG. 5 shows that the heat transfer block 310 includes a
channel 311 therein for receiving a flattened portion 321 of the
heat pipe 320. The heat pipe 320 also includes a pinchoff portion
322 disposed at one end of the flattened portion 321. An end of the
heat pipe 320 opposite the flattened portion 321 is coupled to the
heat dissipation structure (not shown). One end of the channel 311
of the heat transfer block 310 has a flared portion 312 for
receiving the pinchoff portion 322 of the heat pipe 320. A clip
member 340 overlies and secures the flattened portion 321 of the
heat pipe 320 in the channel 311. It will be noted that the clip
member 340 includes a main surface 341, and two side surfaces 342,
343 disposed orthogonal to the main surface. The main surface 341
primarily overlies the flattened portion 321 of the heat pipe 320,
and the two side surfaces 342, 343 primarily reside in single clip
channel 313, when the clip 340 is coupled to the heat transfer
block 310.
[0033] It will be noted that the two side surfaces 342, 343 of the
clip are received in a single clip channel 313 formed in the heat
transfer block 310. The flattened portion 321 of the heat pipe 320
and the clip 340 may be secured in the channel 311 and the single
clip channel 313 respectively by fasteners (e.g., screws, bolts,
etc.), solder, epoxy or other known materials.
[0034] Alternatively, the flattened portion 321 of the heat pipe
320 and the clip 340 may be secured in the channel 311 and the
single clip channel 313 by the surface friction of the flattened
portion and the clip 340 against the walls of the channel 311 and
the single clip channel 313. As stated above with respect to the
first exemplary embodiment, in order to accomplish a tight friction
contact between the channel 311 and the flattened portion 321 of
the heat pipe 320, the channel is made only slightly wider than the
flattened portion, so that the flattened portion fits snugly in the
channels. To effect a tight friction contact between the clip 340
and the single clip channel 313, the side surfaces 342, 343 of the
clip are splayed out (i.e., away from the main surface) slightly,
so that the side surfaces of the clip are urged against the clip
channel walls when the clip is disposed in the heat transfer block
310.
[0035] The heat transfer block 310 also includes guide members 314
with openings 315 formed therein for securing the heat transfer
block to a CPU or chip. Typically, a CPU or chip will include
complementary guide members, such as posts, which may be received
in the openings 315 in order to secure the heat transfer block 310
to the CPU or chip.
[0036] As described above with reference to the heat pipe system
100 of the first exemplary embodiment, the heat pipe system 300 may
be formed by various means such as milling and extrusion.
[0037] Referring to FIGS. 7 and 8, there is shown a heat pipe
system 400 according to a second exemplary embodiment of the
present invention. Similar to the heat pipe system 100, the heat
pipe system 400 includes a heat transfer block 410, a heat pipe
420, and a heat dissipation structure 430. However, the heat pipe
system 400 includes a flattened clip member 440 which extends
across the heat transfer block 410 with tabs 441, 442 formed
therein for being received in respective channels 451, 452 of the
heat transfer block (See FIG. 8).
[0038] FIG. 7 shows that the heat transfer block includes a channel
411 therein for receiving a flattened portion 421 of the heat pipe
420. A clip member 440 overlies and secures the flattened portion
421 of the heat pipe 420 in the channel 411. It will be noted that
the clip member 440 includes a top surface 445, and a bottom
surface 446 with tabs 441, 442 extending orthogonally therefrom
(See FIG. 8).
[0039] The flattened portion 421 of the heat pipe 420 and the clip
440 may be secured in the channel 411 and the clip channels 451,
452 respectively by fasteners (e.g., screws, bolts, etc.), solder,
epoxy or other known materials.
[0040] Alternatively, the flattened portion 421 of the heat pipe
420 and the clip 440 may be secured in the channel 411 and the clip
channels 451, 452 by the surface friction of the flattened portion
and the clip 440 against the walls of the channel 411 and the clip
channels 451, 452. As stated above with respect to the first
exemplary embodiment, in order to accomplish a tight friction
contact between the channel 411 and the flattened portion 421 of
the heat pipe 420, the channel is made only slightly wider than the
flattened portion, so that the flattened portion fits snugly in the
channels. Similarly, to effect a tight friction contact between the
clip 440 and the clip channels 451, 452, the channels are made only
slightly wider than the respective tabs 441, 442.
[0041] The heat transfer block 410 also includes guide members 414
with openings 415 formed therein for securing the heat transfer
block to a CPU or chip. Typically, a CPU or chip will include
complementary guide members, such as posts, which may be received
in the openings 415 in order to secure the heat transfer block 410
to the CPU or chip.
[0042] As described above with reference to the heat pipe system
100 of the first exemplary embodiment, the heat pipe system 400 may
be formed by various means such as milling and extrusion.
[0043] Although the invention has been described in terms of
exemplary embodiments, it is not limited thereto. Rather, the
appended claims should be construed broadly, to include other
variants and embodiments of the invention which may be made by
those skilled in the art without departing from the scope and range
of equivalents of the invention.
* * * * *