U.S. patent application number 12/489413 was filed with the patent office on 2010-03-25 for heat dissipation device and centrifugal fan thereof.
This patent application is currently assigned to FURUI PRECISE COMPONENT (KUNSHAN) CO., LTD.. Invention is credited to Ching-Bai Hwang, Zhi-Hui Zhao.
Application Number | 20100071875 12/489413 |
Document ID | / |
Family ID | 42029245 |
Filed Date | 2010-03-25 |
United States Patent
Application |
20100071875 |
Kind Code |
A1 |
Hwang; Ching-Bai ; et
al. |
March 25, 2010 |
HEAT DISSIPATION DEVICE AND CENTRIFUGAL FAN THEREOF
Abstract
A centrifugal fan includes a housing and a plurality of blades
received in the housing. The housing includes a base wall and a
sidewall surrounding the base wall. The sidewall defines a first
air outlet and a second air outlet adjacent to the first air
outlet. An elongated air guiding plate is located between the first
air outlet and the second air outlet. The air guiding plate
includes an outer end away from the blades and an inner end
adjacent to the blades. A height of the inner end of the air
guiding plate in an axial direction of the centrifugal fan is
smaller than a height of the outer end of the air guiding
plate.
Inventors: |
Hwang; Ching-Bai; (Tu-Cheng,
TW) ; Zhao; Zhi-Hui; (Shenzhen City, CN) |
Correspondence
Address: |
PCE INDUSTRY, INC.;ATT. Steven Reiss
288 SOUTH MAYO AVENUE
CITY OF INDUSTRY
CA
91789
US
|
Assignee: |
FURUI PRECISE COMPONENT (KUNSHAN)
CO., LTD.
KunShan
CN
FOXCONN TECHNOLOGY CO., LTD.
Tu-Cheng
TW
|
Family ID: |
42029245 |
Appl. No.: |
12/489413 |
Filed: |
June 22, 2009 |
Current U.S.
Class: |
165/80.3 ;
165/121; 415/203 |
Current CPC
Class: |
H01L 23/3672 20130101;
H01L 2924/0002 20130101; G06F 1/203 20130101; H01L 2924/0002
20130101; H01L 23/467 20130101; F04D 29/4246 20130101; H01L 2924/00
20130101; F04D 29/422 20130101 |
Class at
Publication: |
165/80.3 ;
415/203; 165/121 |
International
Class: |
F28F 13/00 20060101
F28F013/00; F04D 29/40 20060101 F04D029/40; F28D 21/00 20060101
F28D021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 19, 2008 |
CN |
200810304561.5 |
Claims
1. A centrifugal fan comprising: a plurality of blades; a housing
for receiving the blades therein, the housing comprising a base
wall and a sidewall surrounding the base wall, the sidewall
defining a first air outlet and a second air outlet adjacent to the
first air outlet; and an elongated air guiding plate being located
between the first air outlet and the second air outlet, the air
guiding plate comprising an outer end away from the blades and an
inner end adjacent to the blades, a height of the inner end of the
air guiding plate in an axial direction of the centrifugal fan
being smaller than a height of the outer end of the air guiding
plate.
2. The centrifugal fan as described in claim 1, wherein a maximal
height of the air guiding plate is smaller than a height of the
sidewall.
3. The centrifugal fan as described in claim 1, wherein a distance
between the inner end of the air guiding plate and distal ends of
the blades is no smaller than one millimeter.
4. The centrifugal fan as described in claim 1, wherein an outline
of the base wall comprises an arced section, a first linear section
and a second linear section connected between two opposite ends of
the arced section, the first and second linear sections
corresponding to the first and second air outlets, respectively,
the air guiding plate extending inwardly from a junction of the two
linear sections towards the blades.
5. The centrifugal fan as described in claim 4, wherein an airflow
generated by the blades first reaches the first linear section and
then the second linear section, and an angle formed between the air
guiding plate and the first linear section is smaller than 45
degrees.
6. The centrifugal fan as described in claim 1, wherein the height
of the outer end of the air guiding plate is constant, while the
height of the inner end of the air guiding plate decreases
gradually from the outer end towards the blades.
7. The centrifugal fan as described in claim 6, wherein the air
guiding plate comprises a first lateral surface facing and adjacent
to the first air outlet and a confronting second lateral surface
facing and adjacent to the second air outlet, the first lateral
surface being parallel to the second lateral surface.
8. The centrifugal fan as described in claim 1, wherein a size of a
transverse section of the air guiding plate gradually increases
along a longitudinal direction from a topmost end of the air
guiding plate towards a bottommost end thereof.
9. The centrifugal fan as described in claim 8, wherein the air
guiding plate comprises a first lateral surface facing and adjacent
to the first air outlet and a confronting second lateral surface
facing and adjacent to the second air outlet, the first and second
lateral surfaces intersect with each other and thus forms a side
edge at the inner end of the air guiding plate.
10. A heat dissipation device comprising: a centrifugal fan
comprising a housing and a plurality of blades received in the
housing, the housing comprising a base wall and a sidewall
surrounding the base wall, the sidewall defining a first air outlet
and a second air outlet adjacent to the first air outlet, an
elongated air guiding plate being located between the first air
outlet and the second air outlet, the air guiding plate comprising
an outer end which is adjacent to a side edge of the base wall and
an inner end which is adjacent to the blades, a height of the inner
end of the air guiding plate in an axial direction of the
centrifugal fan being smaller than the height of the outer end of
the air guiding plate; and a first fin unit and a second fin unit
received in the first air outlet and the second fin unit,
respectively.
11. The heat dissipation device as described in claim 10, wherein a
minimal distance between the inner end of the air guiding plate and
the blades is one millimeter.
12. The heat dissipation device as described in claim 10, wherein
the height of the air guiding plate decreases gradually from the
outer end towards the inner end, a maximal height of the air
guiding plate is smaller than a height of the sidewall.
13. The heat dissipation device as described in claim 12, wherein
the air guiding plate comprises a first lateral surface facing and
adjacent to the first air outlet and a confronting second lateral
surface facing and adjacent to the second air outlet, the first
lateral surface being parallel to the second lateral surface.
14. The heat dissipation device as described in claim 12, wherein a
size of a transverse section of the air guiding plate gradually
increases along a longitudinal direction from a topmost end of the
air guiding plate towards a bottommost end thereof.
15. The heat dissipation device as described in claim 10, wherein a
distance between the inner end of the air guiding plate and the
blades is gradually increased along the axial direction of the
centrifugal fan from a bottom to a top thereof.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The disclosure relates to heat dissipation devices, and
particularly to a heat dissipation device having an improved
centrifugal fan.
[0003] 2. Description of Related Art
[0004] With continuing development of the electronic technology,
electronic components such as CPUs generate more and more heat that
is required to be dissipated immediately. Cooling fans are commonly
used in combination with heat sinks for cooling the electronic
components. Since most of electronic devices that contain
electronic components therein, such as a laptop computer, do not
have enough space therein, a centrifugal fan which requires only a
small space for installation is generally used.
[0005] Referring to FIG. 4, a heat dissipation device including a
centrifugal fan 90 in accordance with related art is shown. The
centrifugal fan 90 includes a housing 96 and an impeller 98
received in the housing 96. The housing 96 defines a first air
outlet 91 and a second air outlet 92 perpendicular to the first air
outlet 91. The first and second air outlets 91, 92 are both
rectangular. A first fin unit 93 and a second fin unit 94 are
arranged at the first and second air outlets 91, 92, respectively.
The first fin unit 93 and the second fin unit 94 absorb heat from
electronic components. In operation, the impeller 98 rotates to
drive the airflow to flow towards the first and second fin units
93, 94 via the first and second air outlets 91, 92 to cool the
electronic components continuously.
[0006] As indicated by arrows in FIG. 4, a difference of an amount
of air of the airflow at two ends of each air outlet 91, 92 is
huge, and thus a utilization efficiency of the airflow is low. In
addition, a flow direction of the airflow at a rear end of each air
outlet 91, 92 is substantially perpendicular to channels of the fin
units 93, 94. This deflection of the airflow may cause a loss in
kinetic energy of the airflow. Thus, an amount of air of the
airflow flowing towards the first and second fin units 93, 94 may
be greatly reduced. Heat dissipation efficiency of the heat
dissipation device will thereby be further decreased.
[0007] It is thus desirable to provide a heat dissipation device
which can overcome the described limitations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is an isometric, exploded view of a heat dissipation
device according to a first embodiment.
[0009] FIG. 2 is a top, assembled view of the heat dissipation
device of FIG. 1, with a top cover thereof omitted for purposes of
illustration.
[0010] FIG. 3 is an isometric view of a bottom casing of a
centrifugal fan of a heat dissipation device according to a second
embodiment.
[0011] FIG. 4 is a top view of a conventional heat dissipation
device with some parts thereof removed.
DETAILED DESCRIPTION
[0012] Reference will now be made to the drawing figures to
describe the present heat dissipation device in detail.
[0013] FIGS. 1-2 illustrate a heat dissipation device in accordance
with a first embodiment of the disclosure. The heat dissipation
device includes a first fin unit 20 and a second fin unit 30
thermally connecting with electronic component(s) (not shown) for
absorbing heat therefrom, and a centrifugal fan 10 for providing an
airflow flowing through the first and the second fin units 20, 30
to take the heat away.
[0014] The centrifugal fan 10 includes a housing 12 and an impeller
13 including a plurality of blades 131 rotatably disposed in the
housing 12. The housing 12 includes a bottom casing 11 and a top
cover 14 mounted on the bottom casing 11. The top cover 14 is
plate-shaped, which defines a through hole 15 at a center thereof
functioning as an air inlet for the centrifugal fan 10. The bottom
casing 11 includes a flat base wall 113, a sidewall 112 and an air
guiding plate 19 perpendicular to the top cover 14 and the base
wall 113 of the bottom casing 11. The base wall 113 defines a
through hole 16 at a center thereof, corresponding to the through
hole 15 of the top cover 14 and functioning as another air inlet
for the centrifugal fan 10.
[0015] An outline of the base wall 113 includes an arced section
114, a first linear section 115 and a second linear section 116.
The first and second linear sections 115, 116 are perpendicular to
each other, and intersect with each other. The sidewall 112 extends
upwardly and perpendicularly from the arced section 114 towards the
top cover 14. A first air outlet 17 and a second air outlet 18 are
defined corresponding to the first and second linear sections 115,
116 of the outline of the base wall 113, respectively. Each of the
first and second air outlets 17, 18 is rectangular. The first air
outlet 17 is perpendicular to the second air outlet 18. An air
channel 117 is formed between free ends of the blades 131 and an
inner surface of the sidewall 112 of the bottom casing 11. A width
of the air channel 117 is gradually increased along a clockwise
direction as viewed from FIG. 2 so as to increase the pressure of
the airflow wherein the blades 131 rotate clockwise.
[0016] The air guiding plate 19 is positioned adjacent to a joint
of the first air outlet 17 and the second air outlet 18. The air
guiding plate 19 is elongated, and includes an outer end 191
connected to a junction of the first and second linear sections
115, 116 of the outline of the base wall 113 and an inner end 192
extending inwardly from the outer end 191 towards the blades 131. A
minimal distance between the inner end 192 of the air guiding plate
19 and distal ends of the blades 131 is one millimeter. The air
guiding plate 19 and the base wall 113 of the bottom casing 11 are
integrally formed by injection molding process as a single piece.
Alternatively, the air guiding plate 19 and the base wall 113 can
be molded separately and then be assembled together.
[0017] The outer end 191 of the air guiding plate 19 has a
horizontal top side parallel to a top surface of the base wall 113,
while the inner end 192 of the air guiding plate 19 has a slanted
top side extending downwardly from a distal end of the top side of
the outer end 191 towards the top surface of the base wall 113.
Thus, a longitudinal height of the outer end 191 of the air guiding
plate 19 in an axial direction of the centrifugal fan 10 is
constant, while a longitudinal height of the inner end 192
decreases gradually from the outer end 191 towards the impeller 13.
A maximal longitudinal height of the air guiding plate 19 is
smaller than a longitudinal height of the sidewall 112. The air
guiding plate 19 has a first lateral surface 193 facing and
adjacent to the first air outlet 17 and a confronting second
lateral surface 194 parallel to the first lateral surface 193. The
second lateral surface 194 is adjacent to and faces the second air
outlet 18.
[0018] Referring to FIG. 2, the air guiding plate 19 extends
inwardly from the junction of the linear sections 115, 116 of the
outline of the base wall 113 towards the impeller 13. A first
expanded air passage 118 increasing in width from an inside of the
bottom casing 11 towards the first air outlet 17 is defined between
the first lateral surface 193 of the air guiding plate 19 and the
inner surface of one end of the sidewall 112 of the bottom casing
11 adjacent to the first air outlet 17. A second expanded air
passage 119 increasing in width from the inside of the bottom
casing 11 towards the second air outlet 18 is defined between the
second lateral surface 194 of the air guiding plate 19 and the
inner surface of another end of the sidewall 112 of the bottom
casing 11 adjacent to the second air outlet 18.
[0019] Each of the first and second fin units 20, 30 has a
rectangular configuration corresponding to the first and second air
outlets 17, 18, respectively. The first and second fin units 20, 30
are located at the first and second air outlets 17, 18 and
connected to a wider end of the first and second air passages 118,
119 respectively. In operation of the centrifugal fan 10, the
airflow is driven to flow to the first air outlet 17 firstly, then
pass across the air guiding plate 19 and finally reach the second
air outlet 18, whereby the airflow leaves the first and second air
outlets 17, 18 to take heat away from the first and second fin
units 20, 30 at the first and second air outlets 17, 18,
respectively. Without the air guiding plate 19, as indicated by the
arrows in FIG. 4, the flow direction of the airflow flowing towards
a right side of the first air outlet 91 is substantially parallel
to air passages in a right side of the first fin unit 93, while the
airflow flowing towards a left side of the first air outlet 91
forms an acute angle with air passages in a left side of the first
fin unit 93. Thus, more airflow easily flows into the first fin
unit 93 at the right side of the first air outlet 91, and a
relatively less airflow flows into the first fin unit 93 at the
left side of the first air outlet 91. Similarly, a flow direction
of the airflow flowing towards a bottom side of the second air
outlet 92 is substantially parallel to air passages in a bottom
side of the second fin unit 94, while the airflow flowing towards
an upper side of the second air outlet 12 forms an acute angle with
air passages in an upper side of the second fin unit 94.
[0020] By the provision of the air guiding plate 19 between the
first air outlet 17 and the second air outlet 18, as indicated by
arrows in FIG. 2 of the present disclosure, a portion of the
airflow which originally should flow towards the bottom side of the
second air outlet 18 impinges onto the first lateral surface 193 of
the air guiding plate 19 and is blocked by the guiding plate 19 to
flow back into the first fin unit 20 at the left side of the first
air outlet 17. Thus, an amount of air of the airflow flowing
towards the bottom side of the second air outlet 18 is decreased
and an amount air of the airflow flowing towards the left side of
the first air outlet 17 is accordingly increased, in comparison
with the conventional cooling fan of FIG. 4. Since the top side of
inner end 192 of the air guiding plate 19 extends downwardly from
the top side of the outer end 191 towards the base wall 113, there
is still a sufficient amount of air which can flow through the air
guiding plate 19 to reach the bottom side of the second outlet 18.
Preferably, an angle formed between a projection of the air guiding
plate 19 on the base wall 113 and the first linear section 115 of
the outline of the base wall 113 is smaller than 45 degrees.
Another portion of the airflow can flow through the top side of the
inner end 192 of the air guiding plate 19 to reach the second air
outlet 18, whereby a predetermined amount of air of the airflow
flowing to the second air outlet 18 can be ensured. An air pressure
at the left side of the first air outlet 17 almost equals to an air
pressure at the right side of the first air outlet 17, and an air
pressure at the bottom side of the second air outlet 18 almost
equals to an air pressure at the upper side of the second air
outlet 18, thereby increasing a heat exchange efficiency of the
first and second fin units 20, 30 at the first and second air
outlets 17, 18 with the airflow to increase a heat dissipation
efficiency of the heat dissipation device.
[0021] Furthermore, due to the blocking of the air guiding plate
19, an amount of air of the airflow leaves the cooling fan 10 from
the first air outlet 17 is more than that of the airflow leaves the
cooling fan 10 from the second air outlet 18. That is, the air
pressure of the airflow flowing through the first air outlet 17 is
larger than the air pressure of the airflow flowing through the
second air outlet 18. In use of the cooling fan, the first fin unit
20 located at the first air outlet 17 can absorb heat from a main
electronic component which generates more heat, such a CPU, while
the second fin unit 30 absorbs heat from a secondary electronic
component which generates less heat, such as a power chip; thus,
heat generated by the main electronic component and the secondary
electronic component can be efficiently carried away
simultaneously, thereby increasing utilization efficiency of the
airflow generated by the cooling fan 10.
[0022] FIG. 3 shows a bottom casing 40 of a centrifugal fan in
accordance with a second embodiment. The difference between this
bottom casing 40 and the bottom casing 11 illustrated in the first
embodiment lies in the air guiding plate 49. The air guiding plate
49 of this embodiment is a frustum of a triangular pyramid. The air
guiding plate 49 has a thickness increasing gradually along a
top-to-bottom direction thereof. That is, a size of a transverse
section of the air guiding plate 49 gradually increases along a
longitudinal direction from a topmost end towards a bottommost end
of the air guiding plate 49. The air guiding plate 49 includes a
first lateral surface 44 facing and adjacent to the first air
outlet 17 and an opposite second lateral surface 46 facing and
adjacent to the second air outlet 18. Both the first and second
lateral surfaces 44, 46 are inclined to the base wall 113. A
distance between the first and second lateral surfaces 44, 46 of
the air guiding plate 49 decreases gradually from an outer end 41
of the air guiding plate 49 which is adjacent to a lateral side of
the base wall 113 towards an inner end 42 which is adjacent to the
impeller 13 of the centrifugal fan. The first and second lateral
surfaces 44, 46 intersect with each other and thus form a side edge
45 at the inner end 42 of the air guiding plate 49. The side edge
45 is inclined to the base wall 113 and spaced from the impeller 13
with an increased distance along the bottom-to-top direction of the
air guiding plate 49. A height of the guiding plate 49 gradually
decreases along a direction from the outer end 41 toward the inner
end 42; thus, a top face (not labeled) inclined downwardly from the
outer end 41 toward the inner end 42.
[0023] When the airflow flows from the first air outlet 17 through
the air guiding plate 49 and towards the bottom side of the second
air outlet 18, a portion of the airflow impinges on the first
lateral surface 44 of the air guiding plate 49 and is blocked back
into the first fin unit 20 at the left side of the first air outlet
17. When the airflow impinges on the first and second lateral
surfaces 44, 46 of the air guiding plate 49, each impinged point is
a sound source that generated a narrow band noise. Because the
first and second lateral surface 44, 46 of the air guiding plate 49
are inclined to the base wall 113, the time at which each noise
generated is different. Therefore, the narrow band noises have
different frequencies. Thus, the noises will not be superposed to
generate a noise with a large amplitude. That is, the noise level
generated by the airflow blowing on the air guiding plate 49 near
the first and second air outlet 17, 18 is within a tolerable
range.
[0024] It is to be understood, however, that even though numerous
characteristics and advantages of the disclosure have been set
forth in the foregoing description, together with details of the
structure and function of the embodiments, the disclosure is
illustrative only, and changes may be made in detail, especially in
matters of shape, size, and arrangement of parts within the
principles of the invention to the full extent indicated by the
broad general meaning of the terms in which the appended claims are
expressed.
* * * * *