Information
-
Patent Grant
-
6653755
-
Patent Number
6,653,755
-
Date Filed
Wednesday, May 30, 200123 years ago
-
Date Issued
Tuesday, November 25, 200320 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Ponomarenko; Nicholas
- Cuevas; Pedro J.
Agents
- Blakely, Sokoloff, Taylor & Zafman LLP
-
CPC
-
US Classifications
Field of Search
US
- 310 67 R
- 310 66
- 310 64
- 310 58
- 310 40 R
- 310 10
-
International Classifications
- H02K132
- H02K324
- H02K518
- H02K520
- H02K900
-
Abstract
A fan assembly is described having a circular arrangement of fins located around a circular arrangement of blades. Air leaving tips of the blades has high velocity to efficiently break down a convection barrier layer on each of the fins. By breaking down the convection barrier layer, more heat is transferred from the fins to the air. An additional set of blades is located around the fins and an additional set of fins is located around the additional set of blades. Each fin is attached to a respective turn of a coiled heat pipe. The heat pipe has an end which is thermally connected to a processor of a computer.
Description
BACKGROUND OF THE INVENTION
1). Field of the Invention
This invention relates to a fan assembly for a computer.
2). Discussion of Related Art
A computer usually includes a logic processor which, when operated, generates heat. Logic processors are becoming faster and are generating more heat. Logic processors require cooling in order to maintain functional dignity.
Components that are frequently used for cooling logic processors include fans and heat sinks. In one example, a spreader plate of a heat sink is attached to a logic processor and heat is conducted through the spreader plate to fins attached to the spreader plate. A fan is mounted over the fins and blows air over the fins. The air flows generally in a direction along an axis of rotation of blades of the fan and does not have high speed when leaving the blades. The fins are usually in the form of an extruded bank and are generally located in line.
Due to low velocity of the air when leaving the fan and other factors such as incompatibility of geometries of such a fan and a set if such fins, the air decelerates dramatically before flowing over the fins. Because of a low velocity of the air flowing over the fins, a limited amount of heat can be transferred.
Furthermore, such an arrangement does not optimize the number of fins in a given volume, which makes such an arrangement less suitable for locating within the small confines of a housing of a mobile computer such as a notebook computer.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described by way of example with referenced to the accompanying drawings wherein:
FIG. 1
is a top plan view of a fan assembly for a computer according to an embodiment of the invention;
FIG. 2
is a cross-sectional side view on
2
—
2
in
FIG. 1
; and
FIG. 3
is a cross-sectional side view of a computer having a logic processor connected to a heat pipe of the fan assembly.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 and 2
of the accompanying drawings illustrate a fan assembly
10
for a computer, according to an embodiment of the invention. The fan assembly
10
includes a stationary subassembly
12
and a rotating subassembly
14
. An electric motor
16
includes some components forming part of the stationary subassembly
12
and some components forming part of the rotating subassembly
14
.
The stationary subassembly
12
includes an injection-molded housing
18
, a heat pipe
20
, an inner set of fins
22
, and an outer set of fins
24
.
The fan housing
18
includes a base
26
and sidewalls
28
. A lefthand portion of the base
26
has a circular periphery and a righthand portion of the base
26
has a rectangular periphery. The sidewalls
28
extend upwardly from peripheries of the base
26
. No sidewall is formed on a long edge of the rectangular portion of the base
26
so as to form an exit port
30
above the long edge of the rectangular portion of the base
26
.
The heat pipe
20
is a flat heat pipe which is formed into a spiral shape having outer and inner turns
32
and
34
respectively. The outer turn is larger than and located externally of the inner turn
34
. An outer edge of the outer turn
32
of the heat pipe
20
is secured to upper edges of the sidewalls
28
. The housing
18
and the heat pipe
20
form a stator component shroud defining an enclosure
36
. An opening within the inner turn
34
forms a central inlet port
38
into the enclosure. A gap externally of the inner turn
34
and internally of the outer turn
32
forms an outer inlet port
40
into the enclosure
36
. Air can enter the enclosure
36
through the inlet ports
38
and
40
and exit the enclosure
36
through the exit port
30
.
The fins
22
and
24
are all mounted to the heat pipe
20
and extend from the heat pipe
20
downwardly into the enclosure
36
. The inner fins
22
are all mounted to the inner turn
34
and the outer fins
24
are all mounted to the outer turn
32
. The inner fins
22
form an inner circular arrangement. The outer fins
24
form an outer circular arrangement around the circular arrangement of the inner fins
22
.
The electric motor
16
includes a shaft
42
, a stator
44
, a rotating housing
46
, and windings
48
. The shaft
42
is mounted to the base
26
and the stator
44
is mounted to the shaft
42
. The shaft
42
and the stator
44
form part of the stationary subassembly
12
and are located within the enclosure
36
. The stator
44
has a plurality of salient magnets (not shown) thereon. The windings
48
are secured directly to the rotating housing
46
. The rotating housing
46
is located over the stator
44
with the windings
48
located adjacent the salient magnets on the stator
44
. The rotating housing
46
is mounted to the shaft
42
through a bearing (not shown). The rotating housing
46
is rotatable about an axis
50
extending through the base
26
, the shaft
42
, the stator
44
, and the central inlet port
38
.
Alternating currents can be applied to the windings
48
to create magnetic fields within the rotating housing
46
and through the salient magnets of the stator
44
. By selectively alternating the currents in the windings
48
, rotation can be imparted onto the rotating housing
46
. The windings
48
rotate together with the rotating housing
36
about the axis
50
. The rotating housing
46
and the windings
48
thus form part of the rotating subassembly
14
.
The rotating subassembly
14
further includes a disk-shaped rotor component
52
, an inner set of fan blades
54
, and an outer set of fan blades
56
. The rotor component
52
has a central opening
58
located over the shaft
42
. The rotor component
52
is mounted to the rotating housing
46
as to be rotatable together with the rotating housing about the axis
50
.
The blades
54
and
56
are mounted to the stator component
52
and extend upwardly therefrom. The inner blades
54
are located in an inner circular arrangement adjacent the rotating housing
46
, below the central inlet port
38
. The inner fins
22
are located around the blades
54
. The outer blades
56
are located in a circular arrangement in a gap around the inner fins
22
and within the outer fins
24
and below the outer inlet port
40
. The outer fins
24
, are located around the outer blades
56
. A volute
58
is defined between the outer fins
24
and the sidewalls
28
.
FIG. 3
illustrates a computer
62
including a computer housing
64
and a logic processor
66
. The logic processor
66
is mounted within the computer housing
64
. The computer
62
further includes the fan assembly
10
of
FIGS. 1 and 2
. The fan assembly
10
is mounted within the computer housing
64
. An end of the heat pipe
20
located distant from the fan housing
18
of the fan assembly
10
is located adjacent the processor
66
. An end of the heat pipe
20
is thermally connected to the processor
66
.
In use, electronic signals are transmitted to and from the processor
66
. Operation of the processor
66
causes heat to be generated by the processor
66
. The heat is conducted to a liquid on a wicking layer on an inner surface of the heat pipe
20
. The liquid is heated and evaporates from the wicking layer. A vapor so created flows down the heat pipe
20
to the fan assembly
10
and into the turns
32
and
34
. Heat is transferred from the vapor through a wall of the heat pipe
20
to the fins
22
and
24
.
The rotating subassembly
14
is rotated by alternating the currents and the windings
48
. The blades
54
and
56
are inclined so that they draw air in through the inlet ports
38
and
40
upon rotation. The blades
54
draw air into the central inlet port
38
and the blades
56
draw air into the outer inlet port
40
.
The blades
54
expel the air in a radial direction away from the axis
50
. The air flows from the blades
54
over the fins
22
. The air has high velocity when leaving tips of the blades
54
and when subsequently flowing over the fins
22
. Because of the high velocity, a convection barrier layer on a fin
22
is broken down. Heat can then more effectively be transferred from the fin
22
to the air flowing over the fin
22
when the convection barrier layer is broken down.
The air flowing over the fins
22
then flows over the blades
56
. The air from the fins
22
is mixed with air that is drawn in by the blades
56
through the outer inlet port
40
. The mixture of air is then expelled by the blades
56
over the fins
24
in a radial direction away from the axis
50
. Again, because of high velocity of the air when leaving the blades
56
and when subsequently flowing over the fins
24
, a barrier layer over a fin
24
is more effectively broken down resulting in more efficient transfer of heat from the blade
24
to the air flowing over the blade
24
.
The air flows in radial directions
70
off the fins
24
. Some of the air flowing in the radial directions
70
flows into the volute
58
where the air is collected. The air flows in the volute
58
in tangential directions
72
to the exit port
30
. All the air leaves the enclosure
38
through the exit port
30
. The air leaving through the exit port
30
flows in a direction
74
away from the axis
50
and substantially in a plane of the blades
54
and
56
and the fins
22
and
24
as seen in FIG.
2
.
It can thus be seen that the fan assembly
10
provides for efficient cooling of the processor
66
. The high velocities of the air from tips of the blades
54
and
56
are used to more efficiently cool the fins
22
and
24
. The fins
22
and
24
are located in concentric circular arrangement close to tips of the blades
54
and
56
to ensure that air with high velocity flows over the fins
22
and
24
. A larger number of fins can also be positioned in such concentric circular arrangements than would be the case when, for example, utilizing an extruded bank of fins on one side of the fan assembly
10
, which makes the assembly
10
suitable for locating within the small confines of a mobile computer such as a notebook computer.
Other assemblies may prove suitable for purposes of cooling processors. One assembly may for example utilize only a single circular arrangement of blades and a single circular arrangement of fins. Another assembly may for example utilize a semicircular arrangement of fins surrounding a circular arrangements of fins. The semicircular arrangement of fins would in such an embodiment typically be located near an exit port. It may also be possible that a fan assembly may include a blank of extruded fins located in a row.
While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative and not restrictive of the current invention, and that this invention is not restricted to the specific constructions and arrangements shown and described since modifications may occur to those ordinarily skilled in the art.
Claims
- 1. A fan assembly for a computer, comprising:a stator component; a rotor component mounted to the stator component for rotation about an axis; a first set of blades mounted to the rotor component, the blades expelling air therefrom in a radial direction away from the axis upon rotation of the rotor component; a first set of fins mounted to the stator component in an arrangement at least partially surrounding the first set of blades; and a second set of blades mounted to the rotor component around the first set of fins, air leaving the first set of blades passing over the first set of fins, whereafter the air is expelled by the second set of blades.
- 2. The fan assembly of claim 1 wherein the arrangement of the first set of fins is substantially circular.
- 3. The fan assembly of claim 2 wherein the fins of the first set of fins entirely surround the first set of blades.
- 4. The fan assembly of claim 1 wherein the fins of the first set of fins entirely surround the first set of blades.
- 5. The fan assembly of claim 1 further comprising:a second set of fins mounted to the stator component, the air being expelled by the second set of blades passing over the second set of fins.
- 6. The fan assembly of claim 5 wherein the second set of fins are in an arrangement at least partially surrounding the second set of blades.
- 7. The fan assembly of claim 6 wherein the arrangement of the second set of fins is substantially circular.
- 8. The fan assembly of claim 1 wherein the stator component includes a heat pipe.
- 9. The fan assembly of claim 8 wherein the heat pipe includes a length located adjacent subsequent ones of the fins of the first set of fins.
- 10. The fan assembly of claim 9 wherein the fins of the first set of fins are mounted to the length of the heat pipe.
- 11. The fan assembly of claim 1 wherein the stator component is a shroud forming an enclosure with the blades and the fins in the enclosure, the shroud having an inlet port to allow air into the enclosure and an exit port allowing air out of the enclosure.
- 12. The fan assembly of claim 11 wherein the inlet port allows air into the enclosure substantially in direction of the axis and the exit port allows air out of the enclosure substantially in a direction away from the axis.
- 13. The fan assembly of claim 12 wherein at least 90% of air from the enclosure is expelled to one side of the shroud out of the exit port.
- 14. The fan assembly of claim 12 wherein at least some of the fins of the first set of fins are located between at least some of the blades of the first set of blades and the exit port.
- 15. The fan assembly of claim 11 wherein the shroud includes a heat pipe.
- 16. A fan assembly for a computer, comprising:a stationary subassembly including a stator component and first and second sets of fins mounted to the stator component each set of fins forming at least a partial circular arrangement with the first set of fins located within the circular arrangement of the second set of fins; and a rotating subassembly including a rotor component rotatably mounted to the stator component and first and second sets of blades mounted to the rotor component so as to be rotatable together with the rotor component, each set of blades forming a circular arrangement with the first set of blades located within the circular arrangement of the first set of fins and the second set of blades located within a circular gap defined outerly of the circular arrangement of the first set of fins and internally of the circular arrangement of the second set of fins.
- 17. The fan assembly of claim 16 wherein the stator component includes a heat pipe.
- 18. The fan assembly of claim 16 wherein the stator component is a shroud forming an enclosure with the blades and the fins in the enclosure, the shroud having an inlet port to allow air into the enclosure and an exit port allowing air out of the enclosure.
US Referenced Citations (45)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2002317789 |
Oct 2002 |
JP |