U.S. patent application number 12/399031 was filed with the patent office on 2010-03-11 for fan impeller and heat dissipating device having the same.
This patent application is currently assigned to FU ZHUN PRECISION INDUSTRY (SHEN ZHEN) CO., LTD.. Invention is credited to Jer-Haur Kuo, Shu-Min Li, Shu-Yuan Xu, Xin-Xiang Zha.
Application Number | 20100059210 12/399031 |
Document ID | / |
Family ID | 41798205 |
Filed Date | 2010-03-11 |
United States Patent
Application |
20100059210 |
Kind Code |
A1 |
Li; Shu-Min ; et
al. |
March 11, 2010 |
FAN IMPELLER AND HEAT DISSIPATING DEVICE HAVING THE SAME
Abstract
A heat dissipation device includes an electric fan having a fan
impeller with a hub and a heat sink. A plurality of main blades and
subsidiary blades extend radially and outwardly from the hub and
alternate with each other. The electric fan forms an air inlet and
an air outlet. The main blades have connecting portions on the hub
which are extended towards a center of the hub at the air outlet.
The subsidiary blades have a smaller radial length than the main
blades. The subsidiary blades each have a connecting edge on the
hub which is extended toward the center of the hub adjacent to the
air outlet. The fan impeller drives more air to the center of the
air outlet, whereby more air can flow to a center of the heat
sink.
Inventors: |
Li; Shu-Min; (Shenzhen City,
CN) ; Zha; Xin-Xiang; (Shenzhen City, CN) ;
Xu; Shu-Yuan; (Shenzhen City, CN) ; Kuo;
Jer-Haur; (Tu-Cheng, TW) |
Correspondence
Address: |
PCE INDUSTRY, INC.;ATT. Steven Reiss
288 SOUTH MAYO AVENUE
CITY OF INDUSTRY
CA
91789
US
|
Assignee: |
FU ZHUN PRECISION INDUSTRY (SHEN
ZHEN) CO., LTD.
Shenzhen City
CN
FOXCONN TECHNOLOGY CO., LTD.
Tu-Cheng
TW
|
Family ID: |
41798205 |
Appl. No.: |
12/399031 |
Filed: |
March 6, 2009 |
Current U.S.
Class: |
165/121 ;
416/203 |
Current CPC
Class: |
F04D 29/38 20130101 |
Class at
Publication: |
165/121 ;
416/203 |
International
Class: |
F04D 29/38 20060101
F04D029/38; F28F 13/00 20060101 F28F013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 5, 2008 |
CN |
200810304389.3 |
Claims
1. A fan impeller for generating airflow, comprising: a hub forming
an air inlet and an air outlet at two opposite sides thereof, the
hub having a diameter gradually decreasing along an axial direction
from the air inlet towards the air outlet; a plurality of main
blades extending radially and outwardly from an outer
circumferential surface of the hub, the main blades each having a
connecting edge on the hub, the connecting edge of each main blade
extending towards a center of the hub at the air outlet; and a
plurality of subsidiary blades extending radially and outwardly
from the outer circumferential surface of the hub, the main blades
and the subsidiary blades being alternately arranged around the
hub, each of the subsidiary blades having a smaller radial length
than each of the main blades, each of the subsidiary blades having
a connecting edge on the hub, the connecting edge of the each
subsidiary blade extending towards the center of the hub at the air
outlet, the main blades and the subsidiary blades cooperatively
driving the airflow to a center of the air outlet when the impeller
is rotated.
2. The fan impeller as claimed in claim 1, wherein the main blade
has a greater axial length than the subsidiary blade.
3. The fan impeller as claimed in claim 1, wherein a radial length
of each of the subsidiary blades decreases along an axial direction
from the air inlet towards the air outlet.
4. The fan impeller as claimed in claim 1, wherein the hub defines
a receiving space adjacent to the air inlet.
5. The fan impeller as claimed in claim 4, wherein the hub is
bowl-shaped, the hub forms an inner surface surrounding the
receiving space, and a diameter of the receiving space defined by
the inner surface decreases along an axial direction from the air
inlet towards the air outlet.
6. A heat dissipating device comprising: a heat sink comprising a
plurality of heat dissipating fins; and an electric fan mounted on
the heat sink for generating airflow flowing through the fins of
the heat sink to take away heat from the heat sink, the electric
fan comprising: a hub forming an air inlet and an air outlet, the
air outlet being located between the air inlet and the heat sink,
the hub having a diameter gradually decreasing along an axial
direction from the air inlet towards the air outlet; a plurality of
main blades extending radially and outwardly from an outer
circumferential surface of the hub, the main blades each having a
connecting edge on the hub, the connecting edge of each main blade
extending towards a center of the hub at the air outlet; and a
plurality of subsidiary blades extending radially and outwardly
from the outer circumferential surface of the hub, the blades and
the subsidiary blades being alternately arranged around the hub,
the subsidiary blades each having a smaller radial length than each
of the main blades, the subsidiary blades each having a connecting
edge on the hub, the connecting edge of the each subsidiary blade
extending towards the center of the hub at the air outlet, the main
blades and the subsidiary blades driving the airflow to a center of
the air outlet when the impeller is rotated.
7. The heat dissipating device as claimed in claim 6, wherein each
of the main blades has a greater axial length than each of the
subsidiary blades.
8. The heat dissipating device as claimed in claim 6, wherein a
radial length of each of the subsidiary blades decreases along an
axial direction from the air inlet towards the air outlet.
9. The heat dissipating device as claimed in claim 6, wherein an
end of the hub defines a receiving space adjacent to the air
inlet.
10. The heat dissipating device as claimed in claim 9, wherein the
hub is bowl-shaped, and the hub forms an inner surface surrounding
the receiving space, and a diameter of the receiving space defined
by the inner surface decreases along an axial direction from the
air inlet towards the air outlet.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] Relevant subject matter is disclosed in co-pending U.S.
patent application Ser. No. 12/325,281 filed on Dec. 1, 2008 and
entitled "FAN IMPELLER AND HEAT DISSIPATING DEVICE INCORPORATING
THE SAME". The co-pending U.S. patent application is assigned to
the same assignee as the instant application. The disclosure of the
above-identified co-pending application is incorporated herein by
reference.
BACKGROUND
[0002] 1. Technical Field
[0003] The disclosure relates to a heat dissipating device, and
particularly to an electric fan having an improved fan impeller and
a heat dissipation device having such a fan impeller.
[0004] 2. Description of Related Art
[0005] With continuing development of electronic technology, a
heat-generating electric component such as CPU (central processing
unit) is generating more and more heat which requires immediate
dissipation. Generally, a heat sink is thermally attached to the
CPU, and an electric fan is mounted on the heat sink for providing
an airflow to cool the CPU.
[0006] A typical electric fan includes a fan impeller having a
cylindrical-shaped sidewall and a plurality of blades extending
radially from the sidewall of the fan impeller. A bottom wall of
the fan impeller facing the heat sink is flat and is perpendicular
to the sidewall. When the blades rotate to generate an airflow
flowing to the heat sink, the bottom wall of the fan impeller
prevents the airflow from flowing to a center of the heat sink just
under the fan impeller of the electric fan. FIG. 6 shows a flow
field 92 of the airflow produced by a typical electric fan
simulated by a computational fluid dynamics (CFD) software. The
flow field 92 includes a central dark region through which almost
no air flows and a surrounding bright region through which a strong
air flows. It is found that most of the airflow flows out from a
circumference of the impeller and an amount of the airflow at the
center of the heat sink is approximately zero. However, the center
of the heat sink is usually attached to the heat-generating
electric component and has more heat than other portion of the heat
sink. Thus, the airflow provided by the typical electric fan cannot
efficiently dissipate heat of the heat sink absorbed from the
heat-generating electric component.
[0007] Therefore, a heat dissipation device having an improved fan
impeller is desired to overcome the above describe
shortcomings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is an isometric, exploded view of a heat dissipating
device, according to a first embodiment.
[0009] FIG. 2 is an isometric view of a fan impeller of the heat
dissipating device of FIG. 1.
[0010] FIG. 3 is a plan view of the fan impeller of FIG. 2.
[0011] FIG. 4 is an isometric view of the fan impeller of FIG. 2,
but viewed from another aspect.
[0012] FIG. 5 is a view of an airflow field of the fan impeller of
FIG. 2 simulated by a computational fluid dynamics software.
[0013] FIG. 6 is a view of an airflow field of a prior fan impeller
simulated by a computational fluid dynamics software.
DETAILED DESCRIPTION OF THE EMBODIMENT
[0014] Referring to FIG. 1, a heat dissipating device 10 according
to a first embodiment is shown. The heat dissipating device 10 is
assembled to a heat source (not shown), such as a CPU, for
dissipating heat of the heat source. The heat dissipating device 10
includes a heat sink 4, an electric fan 1, two fixing members 7 for
fixing the electric fan 1 onto the heat sink 4, and two heat pipes
8. The electric fan 1 is mounted on the heat sink 4 and generates
an airflow flowing through the heat sink 4 to take away heat from
the heat sink 4.
[0015] The heat sink 4 includes a base plate 6 and a heat
dissipating body 5 located on the base plate 6. The base plate 6
defines two first receiving grooves 61 in an upper surface 62
thereof. The two first receiving grooves 61 are semi-circular. A
bottom surface 63 of the base plate 6 is used for thermally
contacting with a heat source such as a CPU for absorbing heat
therefrom. The heat dissipating body 5 includes a plurality of
parallel fins 51 spaced from each other. Two adjacent fins 51
define an airflow channel therebetween. Two second receiving
grooves 55 are defined at a bottom portion 54 of the heat
dissipating body 5 corresponding to the two first receiving grooves
61, respectively. The two second receiving grooves 55 are
semi-circular. Each first receiving groove 61 and a corresponding
second receiving groove 55 cooperatively define a circular
receiving channel. The heat dissipating body 5 defines an elongated
groove 53 through a middle of a top portion 56 thereof. The groove
53 is perpendicular to each of the fins 51. Two holes 52 are
defined in the heat dissipating body 5 and symmetrically located at
two opposite sides of the groove 53. Each heat pipe 8 is U-shaped
and includes a condenser section 81 and an evaporator section 82.
The condenser section 81 of each heat pipe 8 is received in one of
the two holes 52. The evaporator section 82 of each heat pipe 8 is
received in one of the two receiving channels. The two fixing
members 7 are symmetrically mounted on a top of the heat
dissipating body 5. The electric fan 1 is fixed onto the fixing
members 7 by screws (not shown).
[0016] Referring also to FIGS. 2-4, the electric fan 1 includes a
fan bracket 2 and a fan impeller 3 received in the fan bracket 2.
The fan impeller 3 includes a hub 31, a plurality of main blades 32
and subsidiary air-guiding blades 33 extending radially and
outwardly from an outer circumferential surface of the hub 31. The
hub 31 is bowl-shaped and includes a bottom wall 317 and a sidewall
314 extending upwardly and outwardly from the bottom wall 317. An
air inlet 311 is formed at a top side of the fan bracket 2 and an
air outlet 312 is formed at a bottom side of the fan bracket 2. The
air outlet 312 is provided adjacent to and faces the heat sink 4.
The bottom wall 317 of the hub 31 is located at the air outlet 312.
The sidewall 314 tapers from the air inlet 311 towards the air
outlet 312. Accordingly, an outer diameter of the hub 31 gradually
decreases along an axial direction from the air inlet 311 towards
the air outlet 312. The hub 31 defines a receiving space 313
adjacent to the air inlet 311. An inner surface 315 of the hub 31
surrounds the receiving space 311. A diameter of the receiving
space 313 defined by the inner surface 315 decreases along the
axial direction from the air inlet 311 towards the air outlet 312.
Each main blade 32 has a connecting side edge 34 on the sidewall
314, and the connecting side edge 34 is extended from the sidewall
314 of the hub 31 at the air inlet 311 towards a center of the hub
31 at the air outlet 312. Each subsidiary air-guiding blades 33 is
located between two adjacent main blades 32. Each subsidiary
air-guiding blades 33 has a much smaller radial length (i.e.,
height) than each main blade 32. A radial length of the subsidiary
air-guiding blades 33 decreases along the axial direction from the
air inlet 311 towards the air outlet 312. The subsidiary
air-guiding blades 33 has a connecting side edge 35 on the sidewall
314, and the connecting side edge 35 is extended from the sidewall
314 of the hub 31 towards a center of the hub 31 at the air outlet
312. The connecting side edge 34 of the main blade 32 has a greater
axial length than the connecting side edge 35 of the subsidiary
air-guiding blades 33. The main blade 32 has a much greater radial
length than the subsidiary air-guiding blades 33. The main blades
32 and the air-guiding blades 33 cooperatively drive the airflow to
a center of the hub 31 at the air outlet 312 when the fan impeller
3 is rotated.
[0017] FIG. 5 shows a flow field 91 of the airflow produced by the
fan impeller 3 simulated by a computational fluid dynamics
software. The flow field 91 includes a central dark region through
which almost no air flows and a surrounding bright region through
which a strong air flows. The dark region of the flow field 91 is
smaller and more uniform than the dark region of the flow field 92
generated by the conventional fan impeller of FIG. 6. When the fan
impeller 3 rotates, the airflow flows from the air inlet 311
towards the heat sink 4. Due to the diameter of the outer
circumference of the hub 31 decreasing along a direction from the
air inlet 311 towards the air outlet 312, more airflow can flow to
the center of the air outlet 312. In addition, the main blades 32
and the air-guiding blades 33 can drive more air of the airflow to
flow to the center of the air outlet 312. Therefore, an amount of
the air of the airflow driven by the fan impeller 3 to the center
of the heat sink 4 is increased. The hub 31 occupies a smaller
space than a conventional hub. Thus the main blades 32 can have a
relatively larger size. Accordingly, the amount of airflow
generated by the main blades 32 is increased in comparison with the
prior art.
[0018] It will be obvious that, within the scope of the invention,
many variations are possible to those skilled in the art. The scope
of protection of the invention is not limited to the example given
herein.
* * * * *