U.S. patent application number 11/308234 was filed with the patent office on 2006-12-28 for cooling fan.
Invention is credited to Ching-Bai Hwang, Guo-Wen Zhang, Xi-Jian Zhu.
Application Number | 20060292020 11/308234 |
Document ID | / |
Family ID | 37567607 |
Filed Date | 2006-12-28 |
United States Patent
Application |
20060292020 |
Kind Code |
A1 |
Hwang; Ching-Bai ; et
al. |
December 28, 2006 |
COOLING FAN
Abstract
A cooling fan includes a motor (30) for generating an airflow,
and a housing (10) defining a space (40) for receiving the motor
therein. The housing defines an air inlet (57) through which the
airflow flows into the housing. The motor has a plurality of fan
blades (31) extending radially outwards from a periphery thereof.
The motor is mounted under the air inlet. The air inlet is so
configured or positioned that the fan blades are unevenly exposed
to an ambient air through the air inlet. The housing further has an
air outlet (56) through which the airflow flows out of the fan. The
air outlet is oriented perpendicular to the air inlet.
Inventors: |
Hwang; Ching-Bai; (Shenzhen,
CN) ; Zhu; Xi-Jian; (Shenzhen, CN) ; Zhang;
Guo-Wen; (Shenzhen, CN) |
Correspondence
Address: |
NORTH AMERICA INTELLECTUAL PROPERTY CORPORATION
P.O. BOX 506
MERRIFIELD
VA
22116
US
|
Family ID: |
37567607 |
Appl. No.: |
11/308234 |
Filed: |
March 14, 2006 |
Current U.S.
Class: |
417/423.13 |
Current CPC
Class: |
F04D 29/4213 20130101;
F04D 29/4226 20130101 |
Class at
Publication: |
417/423.13 |
International
Class: |
F04B 17/00 20060101
F04B017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 24, 2005 |
CN |
200510035548.0 |
Claims
1. A cooling fan comprising: a motor for generating an airflow; and
a housing defining a space for receiving the motor therein; wherein
the housing defines a noncircular air inlet for air flowing into
the housing therethrough when the motor is operated in a top wall
thereof, and an air outlet for the air to leave the housing, the
air inlet being oriented perpendicular to the air outlet, the
housing having a front side, a rear side and two lateral sides
between the front and rear sides.
2. The cooling fan as claimed in claim 1, wherein a center of the
air inlet is laterally offset from a center of the motor.
3. The cooling fan as claimed in claim 1, wherein the air inlet is
elliptic or irregular.
4. The cooling fan as claimed in claim 1, wherein the housing
comprises a cover defining the air inlet therein and a base for
mounting the cover thereon, the base defines an opening parallel to
the air inlet.
5. The cooling fan as claimed in claim 4, wherein a center of the
opening is laterally offset from the center of the motor.
6. The cooling fan as claimed in claim 5, wherein the opening is
elliptic or irregular.
7. The cooling fan as claimed in claim 1, wherein the air inlet is
located at the front side of the housing.
8. The cooling fan as claimed in claim 7, wherein housing defines
an additional air outlet at one of the lateral sides of the
housing, the additional air outlet is oriented perpendicular to the
air outlet and the air inlet.
9. A cooling fan comprising: a motor having a plurality of blades
for generating an airflow; and a housing defining a space for
receiving the motor therein, the housing defining an air inlet
therein; wherein a distance between a circumference of the air
inlet and a center of the motor is various along a circumferential
direction of air inlet.
10. The cooling fan as claimed in claim 9, wherein the air inlet is
noncircular.
11. The cooling fan as claimed in claim 10, wherein the air inlet
is elliptic or irregular.
12. The cooling fan as claimed in claim 9, wherein a center of the
air inlet is radially offset from a center of the motor.
13. The cooling fan as claimed in claim 9, wherein the housing
defines an air outlet perpendicular to the air inlet, and a
plurality of fins is received in the air outlet of the housing.
14. The cooling fan as claimed in claim 9, wherein the housing
defines two air inlets at a front side and a lateral side of the
housing, respectively.
15. A cooling fan comprising: a hosing having a top wall, a rear
side, a front side and two lateral sides between the rear side and
the front side, an air inlet defined in the top wall through which
air flows into the housing, and an air outlet through which the air
leaves the housing, the air outlet being oriented perpendicular to
the air inlet; and a motor rotatably received in the housing under
the air inlet, having a plurality of fan blades extending radially
outwardly from a periphery of the motor, when the motor rotates,
the fan blades drawing the air into the housing via the air inlet
and expelling the air out of the housing via the air outlet;
wherein the fan blades are unevenly exposed to an ambient air
through the air inlet.
16. The cooling fan as claimed in claim 15, wherein the air inlet
is circular and has a center, the motor is circular and has a
center, the center of the air inlet is laterally offset from the
center of the motor.
17. The cooling fan as claimed in claim 15, wherein the air inlet
is elliptic and has a center, the motor is circular and has a
center, the center of the air inlet is coincidental with the center
of the motor.
18. The cooling fan as claimed in claim 15, wherein the air inlet
is elliptic and has a center, the motor is circular and has a
center, the center of the air inlet is laterally offset from the
center of the motor.
19. The cooling fan as claimed in claim 15, wherein the air inlet
has an irregular shape.
20. The cooling fan as claimed in claim 16, wherein the housing
further has a second outlet, the second outlet is oriented
perpendicular to the air inlet and the air outlet.
21. The cooling fan as claimed in claim 16, wherein when the fan
blades rotate along a clockwise direction as viewed from a top of
the fan, the center of the air inlet is located near a right side
of the housing than the center of the motor.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to a cooling fan,
and more particularly to a design of an air inlet of a centrifugal
cooling fan (blower) in order to improve performance thereof.
DESCRIPTION OF RELATED ART
[0002] With continuing development of the electronic technology,
electronic packages such as CPUs are generating more and more heat
that is required to be dissipated immediately. Conventional cooling
fans are commonly used for cooling the CPUs and other
heat-generating electronic components.
[0003] A conventional cooling fan typically can be classified into
two types: axial fan and centrifugal fan (blower). The blower is
more suitably used in a laptop computer since it has a flat
configuration and a large air flow rate. A blower comprises a motor
and a housing receiving the motor therein. The housing defines at
least an air inlet and an air outlet. The inlet and outlet are
oriented to be perpendicular to each other. An airflow generated by
the motor flows into the housing via the air inlet and out of the
housing through the air outlet. The motor comprises a stator and a
rotor being rotatable with respect to the stator. The rotor
includes a plurality of fan blades extending radially from an
outer-periphery of the rotor and a shaft extending downwardly
thereof. The stator includes a bearing ratatably receiving the
shaft therein. The most direct and effective way to improve cooling
and heat dissipation efficiency of the cooling fan (blower) is to
increase the air flow rate thereof. Increasing the air flow rate
can be achieved by different measures, for example, by increasing
the revolution speed (i.e. rpm (revolutions per minute)) of the fan
or by increasing the size of the fan.
[0004] Increasing the revolution speed of the fan increases the air
flow rate of the fan; therefore, the cooling and heat dissipation
effectiveness is relatively improved. However, increasing the
revolution speed of the fan causes a bearing of the fan to wear
quickly. Furthermore, heat produced by friction between a shaft and
the bearing of the fan causes the bearing to be damaged quickly,
resulting in short service life of the cooling fan. On the other
hand, to increase the size of the fan is not practical since the
computer industry has required the computer components to be
smaller and smaller.
[0005] Furthermore, keeping the fan blades in balance is another
important factor to be taken into account when wishing to increase
the air flow rate by increasing the revolving speed of the fan. If
the fan blades are not arranged in precise balance, the blades will
vibrate when operating the cooling fan at a high speed, which
affects the operation quality of the cooling fan and its service
life. Nevertheless, a precise balance of the fan blades means a
high manufacturing cost. Therefore, it is not a good idea to
increase the air flow rate of the cooling fan simply by increasing
the revolving speed of the fan blades. Further, increasing the
revolving speed of the fan blades also results in consuming more
power and increasing more heat.
[0006] Therefore, it is desired to design a blower which can
increase the amount of airflow without either increasing the
revolving speed of the fan or increasing the size of the
blower.
SUMMARY OF INVENTION
[0007] According to a preferred embodiment of the present
invention, a cooling fan comprises a motor for generating an
airflow, and a housing defining a space for receiving the motor
therein. The housing defines an air inlet for enabling the airflow
to enter the housing. The air inlet is circular and has a center.
The center of the air inlet is laterally offset from a center of
the motor. By such design, the airflow can be more smoothly drawn
into the housing through the air inlet. Accordingly, air flow rate
of the cooling fan is increased, whereby the cooling and heat
dissipation efficiency of the cooling fan is improved.
[0008] Other advantages and novel features of the present invention
will be drawn from the following detailed description of a
preferred embodiment of the present invention with attached
drawings, in which:
BRIEF DESCRIPTION OF DRAWINGS
[0009] FIG. 1 is an isometric, assembled view of a cooling fan in
accordance with a preferred embodiment of the present
invention.
[0010] FIG. 2 is an isometric, explored view of the cooling fan of
FIG. 1;
[0011] FIG. 3 is similar to FIG. 1, but showing a second embodiment
of the cooling fan;
[0012] FIG. 4 shows a third embodiment of the cooling fan; and
[0013] FIG. 5 shows a forth embodiment of the cooling fan.
DETAILED DESCRIPTION
[0014] Referring to FIGS. 1-2, a cooling fan according to a
preferred embodiment of the present invention includes a housing 10
and a motor 30 received in the housing 10. The cooling fan is a
centrifugal fan which is also called as a blower.
[0015] The housing 10 includes a base 20 and a cover 50 mounted on
the base 20. Together the base 20 and cover 50 defines a space 40
for receiving the motor 30 therein. The base 20 is approximately
planar and has a circular rear side. Four mounting portions 28
extend outwardly from the base 20 for securing the base 20 with the
cover 50. The mounting portions 28 are arranged along a
circumferential periphery of the base 20. Each mounting portion 28
defines a mounting hole 29 therein for extension of a fixing
element (not labeled), such as a rivet. A protrusion 21 extends
outwardly from a front edge of the base 20. A plurality of fins 22
is arranged on the protrusion 21. A flow channel 23 is defined
between each two adjacent fins 22.
[0016] A central tube 24 extends upwardly from a central portion of
the base 20 for supporting the motor 30 thereon. An opening 25 is
defined in the base 20 around the central tube 24. The opening 25
is circular and has a center at A. The center A is laterally offset
from a center of a curvature of the circular rear side of the base
20. Three ribs 27 connect the base 20 and the central tube 24, and
separate the opening 25 into three portions.
[0017] The cover 50 includes a top wall 51 and a sidewall 53
extending downwardly from an outer-periphery of the top wall 51.
The top wall 51 has a shape and size similar to the base 20. A
circular shaped air inlet 57 is defined in the top wall 51 and
communicates with the space 40 of the housing 10. The air inlet 57
has a center at B. The center B of the air inlet 57 is laterally
offset from the center A of the opening 25 of the base 20. An ear
58 extends outwardly from the outer-periphery of the sidewall 53
for connection with a corresponding mounting portion 28 of the base
20. The ear 58 defines a through hole 59 for being aligned with the
mounting hole 29 of the corresponding mounting portion 28. A flange
55 extends outwardly from a front edge of the cover 50
corresponding to the protrusion 21 of the base 20. Together the
flange 55 and protrusion 21 define an air outlet 56 receiving the
fins 22 therein. The air outlet 56 communicates with the air inlet
57 via the space 40 of the housing 10, and is perpendicular to the
air inlet 57.
[0018] The motor 30 is received in the housing 10 and supported by
the central tube 24. The motor 30 is located under the air inlet
57. The motor 30 is circular and defines a center at C. A plurality
of fan blades 31 extends radially and outwardly from an
outer-periphery of the motor 30. An outer edge of the fan blades 31
defines a circle V. A center of the circle V is coincidental with
the center C of the motor 30 and the center A of the opening 25 of
the base 20, but is laterally offset from the center B of the air
inlet 57 of the cover 50.
[0019] During assembly, the cover 50 fixedly secures with the base
20 and together defines the space 40 therein. The fixing elements
extend through the through holes 59 of the cover 50 and the
mounting holes 29 of the base 20 to secure the cover 50 with the
base 20. The motor 30 is received in the housing 10 and supported
by the central tube 24. The center C of the motor 30 is laterally
offset from the center B of the air inlet 57; thus, a distance
between the circumference of the air inlet 57 and the center C of
the motor 30 is various. Since the center of the circle V is
coincidental with the center A of the opening 25, and the center A
is laterally offset from the center of the curvature of the
circular rear side of the base 20; thus, the center of the circle V
is laterally offset from the center of the curvature of the
circular rear side base 20. In this embodiment, the center of the
circle V is located close to a left lateral side of the base 20 as
viewed from FIGS. 1 and 2. Thus, a wedge-shaped interspace is
defined between the inner surface of the sidewall 53 and the circle
V. The distance between the inner surface of the sidewall 53 of the
housing 10 and the circle V increases along the rotation direction
of the motor 30. In this embodiment, the motor 30 rotates clockwise
as viewed from FIG. 1.
[0020] During operation of the cooling fan, the protrusion 21 of
the base 20 is thermally connected with a heat generating device
(not shown). A power supply (not shown) provides a voltage to the
motor 30 to drive the motor 30 to rotate. Then the rotary motor 30
brings an airflow flowing through the air inlet 57 into the housing
10. The fan blades 31 push the airflow flowing along the rotation
direction of the motor 30, and finally form an airflow having a
relatively larger amount and pressure. The airflow flows through
the flow channels 23 of the fins 22 in the air outlet 56, and take
away the heat of the fins 22 absorbed from the heat generating
device. Since the center B of the air inlet 57 is laterally offset
from the center C of the motor 30, the air inlet 57 and the motor
30 are not concentric to each other. By such design, the fan blades
31 are unevenly exposed to an ambient air through the air inlet 57,
and the air can be more smoothly drawn into the space 40 via the
air inlet 57 by the fan blades 31. Turbulence of the airflow
generated at the air inlet 57 can be reduced. Thus, the flow loss
of the airflow decreases, and finally improves the pressure and
velocity of the airflow. Accordingly, the amount of airflow (or air
flow rate) of the cooling fan is increased, and finally improves
the cooling and heat dissipation efficiency of the cooling fan. The
center B of the air inlet 57 is located near a right lateral side
of the base than the center C of the motor 30 as viewed from FIG.
1.
[0021] FIG. 3 illustrates the cooling fan in accordance with a
second embodiment of the present invention. Except for the air
inlet 357 of the cover 350, other parts of the cooling fan in
accordance with the second embodiment are substantially the same as
the cooling fan of the previous embodiment. The air inlet 357 is
noncircular, and has an elliptic shape. The center of the air inlet
357 is coincidental with the center C of the motor 30. Then the air
inlet 357 has a shaped different from that of the motor 30. The fan
blades 31 are unevenly exposed to the ambient air through the air
inlet 357. Thus, the air inlet 357 can more smoothly guide the
airflow flowing into the space 40 of the housing, and reduces the
flow loss of the airflow and improves the amount of airflow. In a
modification of this embodiment, the center B of the air inlet 357
can be laterally offset from the center C of the motor 30.
[0022] Referring to FIG. 4, it illustrates the cooling fan in
accordance with a third embodiment of the present invention.
Similar to the previous embodiments, the cooling fan also comprises
the cover 450 having an air inlet 457 and the motor 30 received
therein. The difference of the third embodiment over the previous
embodiments is that the air inlet 457 is irregular shaped. The
shape of the air inlet 457 is neither circular nor elliptic. By
such design the fan blades non-uniformly exposed through the air
inlet.
[0023] Referring to FIG. 5, in this embodiment the cooling fan
having a pair of air outlets 556. The two air outlets 556 are
perpendicular to the air inlet 557 of the cover 550 and
perpendicular to each other. Thus, the airflow generated by the
cooling fan is separated into two sub-flows which flow out the
housing in two perpendicular directions through the outlets 556.
Then the airflow can be sufficiently utilized to dissipate heat
generated by the different devices arranged at different positions.
In this embodiment, the geometry relationship between the air inlet
557 and the motor is the same as the first embodiment.
[0024] Each of the previous embodiments of the cooling fan defines
a circular shaped opening 25 in the base 20 of the cooling fan. The
center A of the opening 25 is coincidental with the center C of the
motor 30. The opening 25 acts as a second air inlet for improving
the air flow rate of the fan. The shape of the opening 25 can be
various as circular, elliptic or irregular. Furthermore, the center
A of the opening 25 may be laterally offset from the center C of
the motor 30 as the center B of the air inlet 57 of the first
embodiment.
[0025] It is understood that the invention may be embodied in other
forms without departing from the spirit thereof. Thus, the present
example and embodiment is to be considered in all respects as
illustrative and not restrictive, and the invention is not to be
limited to the details given herein.
* * * * *