U.S. patent application number 13/612885 was filed with the patent office on 2014-03-13 for fan impeller structure of centrifugal fan.
This patent application is currently assigned to ASIA VITAL COMPONENTS CO., LTD.. The applicant listed for this patent is Chun-Ming Wu. Invention is credited to Chun-Ming Wu.
Application Number | 20140072434 13/612885 |
Document ID | / |
Family ID | 50233457 |
Filed Date | 2014-03-13 |
United States Patent
Application |
20140072434 |
Kind Code |
A1 |
Wu; Chun-Ming |
March 13, 2014 |
FAN IMPELLER STRUCTURE OF CENTRIFUGAL FAN
Abstract
A fan impeller structure of centrifugal fan includes a hub, a
first blade body set and a second blade body set. The hub has an
extension section having a first side and a second side. The first
blade body set is disposed on the first side, while the second
blade body set is disposed on the second side. The first blade body
set defines multiple first air inlets and multiple first air
outlets. The second blade body set defines multiple second air
inlets and multiple second air outlets. The first air outlets of
the first blade body set or the second air outlets of the second
blade body set are selectively arranged at unequal intervals so as
to effectively reduce noise.
Inventors: |
Wu; Chun-Ming; (New Taipei
City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Wu; Chun-Ming |
New Taipei City |
|
TW |
|
|
Assignee: |
ASIA VITAL COMPONENTS CO.,
LTD.
New Taipei City
TW
|
Family ID: |
50233457 |
Appl. No.: |
13/612885 |
Filed: |
September 13, 2012 |
Current U.S.
Class: |
416/198R |
Current CPC
Class: |
F04D 29/281 20130101;
F04D 29/666 20130101; F04D 29/30 20130101; F04D 17/162
20130101 |
Class at
Publication: |
416/198.R |
International
Class: |
F04D 29/28 20060101
F04D029/28 |
Claims
1. A fan impeller structure of centrifugal fan, comprising: a hub
having an extension section, the extension section having a first
side and a second side; a first blade body set disposed on the
first side, the first blade body set including multiple first blade
bodies, the first blade bodies defining therebetween multiple first
air inlets and multiple first air outlets, the first air outlets
being arranged at unequal intervals; and a second blade body set
disposed on the second side, the second blade body set including
multiple second blade bodies, the second blade bodies defining
therebetween multiple second air inlets and multiple second air
outlets.
2. The fan impeller structure of centrifugal fan as claimed in
claim 1, wherein the first blade body set extends from the first
side of the extension section in a direction away from the hub,
each first blade body having a first end and a second end, the
first air inlet being defined between the first ends of each two
adjacent first blade bodies, the first air outlet being defined
between the second ends of each two adjacent first blade bodies,
the second blade body set extending from the second side of the
extension section in a direction away from the hub, each second
blade body having a third end and a fourth end, the second air
inlet being defined between the third ends of each two adjacent
second blade bodies, the second air outlet being defined between
the fourth ends of each two adjacent second blade bodies.
3. The fan impeller structure of centrifugal fan as claimed in
claim 2, wherein the first ends together define a first pitch
circle, a tangent of the first pitch circle at the first end being
defined as a first tangent, the first blade body having a first
blade body central line, a tangent of the first blade body central
line at the first end being defined as a second tangent, the second
tangent intersecting the first tangent to contain a first air
incoming angle, the second ends together defining a second pitch
circle, a tangent of the second pitch circle at the second end
being defined as a third tangent, a tangent of the first blade body
central line at the second end being defined as a fourth tangent,
the third tangent and the fourth tangent containing a first air
outgoing angle, the third ends together defining a third pitch
circle, a tangent of the third pitch circle at the third end being
defined as a fifth tangent, the second blade body having a second
blade body central line, a tangent of the second blade body central
line at the third end being defined as a sixth tangent, the fifth
tangent intersecting the sixth tangent to contain a second air
incoming angle, the fourth ends together defining a fourth pitch
circle, a tangent of the fourth pitch circle at the fourth end
being defined as a seventh tangent, a tangent of the second blade
body central line at the fourth end being defined as an eighth
tangent, the seventh tangent and the eighth tangent containing a
second air outgoing angle.
4. The fan impeller structure of centrifugal fan as claimed in
claim 3, wherein the first air incoming angle is larger than or
equal to the second air incoming angle.
5. The fan impeller structure of centrifugal fan as claimed in
claim 3, wherein the first air outgoing angle is larger than or
equal to the second air outgoing angle.
6. The fan impeller structure of centrifugal fan as claimed in
claim 3, wherein the first air incoming angle is smaller than or
equal to the second air incoming angle.
7. The fan impeller structure of centrifugal fan as claimed in
claim 3, wherein the first air outgoing angle is smaller than or
equal to the second air outgoing angle.
8. The fan impeller structure of centrifugal fan as claimed in
claim 2, wherein the second end has a height larger than that of
the fourth end.
9. The fan impeller structure of centrifugal fan as claimed in
claim 2, wherein the fourth end has a height larger than that of
the second end.
10. The fan impeller structure of centrifugal fan as claimed in
claim 1, wherein the first blade body has a length larger than that
of the second blade body.
11. The fan impeller structure of centrifugal fan as claimed in
claim 1, wherein the second blade body has a length larger than
that of the first blade body.
12. The fan impeller structure of centrifugal fan as claimed in
claim 2, wherein the first end is aligned with the third end.
13. The fan impeller structure of centrifugal fan as claimed in
claim 3, wherein the first end is not aligned with the third end
and the first and second air inlets are not aligned with each
other.
14. The fan impeller structure of centrifugal fan as claimed in
claim 1, wherein the number of the first blade bodies is more than
the number of the second blade bodies.
15. The fan impeller structure of centrifugal fan as claimed in
claim 1, wherein the number of the second blade bodies is more than
the number of the first blade bodies.
16. The fan impeller structure of centrifugal fan as claimed in
claim 1, wherein the second blade bodies of the second blade body
set are arranged at equal intervals or unequal intervals.
17. A fan impeller structure of centrifugal fan, comprising: a hub
having an extension section, the extension section having a first
side and a second side; a first blade body set disposed on the
first side, the first blade body set including multiple first blade
bodies, the first blade bodies defining therebetween multiple first
air inlets and multiple first air outlets, the first air outlets
being arranged at equal intervals; and a second blade body set
disposed on the second side, the second blade body set including
multiple second blade bodies, the second blade bodies defining
therebetween multiple second air inlets and multiple second air
outlets, the second air outlets being arranged at unequal
intervals.
18. The fan impeller structure of centrifugal fan as claimed in
claim 17, wherein the first blade body set extends from the first
side of the extension section in a direction away from the hub,
each first blade body having a first end and a second end, the
first air inlet being defined between the first ends of each two
adjacent first blade bodies, the first air outlet being defined
between the second ends of each two adjacent first blade bodies,
the second blade body set extending from the second side of the
extension section in a direction away from the hub, each second
blade body having a third end and a fourth end, the second air
inlet being defined between the third ends of each two adjacent
second blade bodies, the second air outlet being defined between
the fourth ends of each two adjacent second blade bodies.
19. The fan impeller structure of centrifugal fan as claimed in
claim 18, wherein the first ends together define a first pitch
circle, a tangent of the first pitch circle at the first end being
defined as a first tangent, the first blade body having a first
blade body central line, a tangent of the first blade body central
line at the first end being defined as a second tangent, the second
tangent intersecting the first tangent to contain a first air
incoming angle, the second ends together defining a second pitch
circle, a tangent of the second pitch circle at the second end
being defined as a third tangent, a tangent of the first blade body
central line at the second end being defined as a fourth tangent,
the third tangent and the fourth tangent containing a first air
outgoing angle, the third ends together defining a third pitch
circle, a tangent of the third pitch circle at the third end being
defined as a fifth tangent, the second blade body having a second
blade body central line, a tangent of the second blade body central
line at the third end being defined as a sixth tangent, the fifth
tangent intersecting the sixth tangent to contain a second air
incoming angle, the fourth ends together defining a fourth pitch
circle, a tangent of the fourth pitch circle at the fourth end
being defined as a seventh tangent, a tangent of the second blade
body central line at the fourth end being defined as an eighth
tangent, the seventh tangent and the eighth tangent containing a
second air outgoing angle.
20. The fan impeller structure of centrifugal fan as claimed in
claim 19, wherein the first air incoming angle is larger than or
equal to the second air incoming angle.
21. The fan impeller structure of centrifugal fan as claimed in
claim 19, wherein the first air outgoing angle is larger than or
equal to the second air outgoing angle.
22. The fan impeller structure of centrifugal fan as claimed in
claim 19, wherein the first air incoming angle is smaller than or
equal to the second air incoming angle.
23. The fan impeller structure of centrifugal fan as claimed in
claim 19, wherein the first air outgoing angle is smaller than or
equal to the second air outgoing angle.
24. The fan impeller structure of centrifugal fan as claimed in
claim 18, wherein the second end has a height larger than that of
the fourth end.
25. The fan impeller structure of centrifugal fan as claimed in
claim 18, wherein the fourth end has a height larger than that of
the second end.
26. The fan impeller structure of centrifugal fan as claimed in
claim 17, wherein the first blade body has a length larger than
that of the second blade body.
27. The fan impeller structure of centrifugal fan as claimed in
claim 17, wherein the second blade body has a length larger than
that of the first blade body.
28. The fan impeller structure of centrifugal fan as claimed in
claim 18, wherein the first end is aligned with the third end.
29. The fan impeller structure of centrifugal fan as claimed in
claim 19, wherein the first end is not aligned with the third end
and the first and second air inlets are not aligned with each
other.
30. The fan impeller structure of centrifugal fan as claimed in
claim 17, wherein the number of the first blade bodies is more than
the number of the second blade bodies.
31. The fan impeller structure of centrifugal fan as claimed in
claim 17, wherein the number of the second blade bodies is more
than the number of the first blade bodies.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to a fan impeller
structure of a centrifugal fan, and more particularly to a
double-layer fan impeller structure of a centrifugal fan in which
at least one layer of blades of the upper and lower layers is
selectively arranged at unequal intervals so as to lower the single
tone of the blade passing frequency (BPF) and greatly reduce
noise.
[0003] 2. Description of the Related Art
[0004] Along with the rapid development of electronic industries,
the performance of the electronic components has been more and more
enhanced. The electronic components have operated at higher and
higher speed. In the meantime, the heat generated by the electronic
components has become higher and higher. In case the heat is not
dissipated in time, the operation performance of the electronic
components will be deteriorated. In some more serious cases, the
electronic components may even burn out. In order to dissipate the
heat, a miniaturized centrifugal fan is installed in a limited
space of the system for carrying away the heat. The centrifugal fan
includes a frame body, a fan hub and multiple blade bodies
annularly disposed around outer circumference of the fan hub. Each
of upper and lower sides of the frame body is formed with an air
inlet. A lateral side of the frame body is formed with an air
outlet. In operation, the blade bodies rotate to drive the ambient
air to flow. The axial airflow going into the frame body from the
air inlet is turned to radial airflow, which is exhausted from the
air outlet.
[0005] When the centrifugal fan operates, the non-uniform wake
flowing out from the fan impeller will interact with the tongue to
make noise. In the case that the gap between the fan impeller and
the tongue is relatively narrow, the noise will be affected by the
tongue oscillation caused by the impact of the non-uniform wake
onto the tongue and the pressure difference around the tongue. In
the case that the gap is 20% the radius of the fan impeller, only
the non-uniform wake will affect the major noise source and the
non-uniform wake only has little affection on the major noise
source. In addition, the wake strength can be lowered by means of
adding short vanes between the blades. This can minimize the
affection of the non-uniform wake on the pressure turbulence and
the noise. According to the above, the conventional technique has
the following shortcomings: [0006] 1. The structural design is
limited. [0007] 2. The ratio of upper incoming air volume to lower
incoming air volume cannot be flexibly designed according to the
characteristics. [0008] 3. The noise is loud.
SUMMARY OF THE INVENTION
[0009] It is therefore a primary object of the present invention to
provide a fan impeller structure of centrifugal fan, which can
effectively reduce noise.
[0010] To achieve the above and other objects, the fan impeller
structure of centrifugal fan of the present invention includes a
hub, a first blade body set and a second blade body set.
[0011] The hub has an extension section. The extension section has
a first side and a second side. The first blade body set is
disposed on the first side. The first blade body set includes
multiple first blade bodies. The first blade bodies define
therebetween multiple first air inlets and multiple first air
outlets. The first air outlets are arranged at unequal intervals.
The second blade body set is disposed on the second side. The
second blade body set includes multiple second blade bodies. The
second blade bodies define therebetween multiple second air inlets
and multiple second air outlets. The second air outlets are
arranged at equal intervals.
[0012] Still to achieve the above and other objects, the fan
impeller structure of centrifugal fan of the present invention
includes a hub, a first blade body set and a second blade body
set.
[0013] The hub has an extension section. The extension section has
a first side and a second side. The first blade body set is
disposed on the first side. The first blade body set includes
multiple first blade bodies. The first blade bodies define
therebetween multiple first air inlets and multiple first air
outlets. The first air outlets are arranged at unequal intervals.
The second blade body set is disposed on the second side. The
second blade body set includes multiple second blade bodies. The
second blade bodies define therebetween multiple second air inlets
and multiple second air outlets. The second air outlets are
arranged at unequal intervals.
[0014] Still to achieve the above and other objects, the fan
impeller structure of centrifugal fan of the present invention
includes a hub, a first blade body set and a second blade body
set.
[0015] The hub has an extension section. The extension section has
a first side and a second side. The first blade body set is
disposed on the first side. The first blade body set includes
multiple first blade bodies. The first blade bodies define
therebetween multiple first air inlets and multiple first air
outlets. The first air outlets are arranged at equal intervals. The
second blade body set is disposed on the second side. The second
blade body set includes multiple second blade bodies. The second
blade bodies define therebetween multiple second air inlets and
multiple second air outlets. The second air outlets are arranged at
unequal intervals.
[0016] The first air outlets of the first blade body set or the
second air outlets of the second blade body set are selectively
arranged at unequal intervals. This can lower the single tone of
the blade passing frequency (BPF). Moreover, the double-layer fan
impeller structure can increase the blade passing frequency (BPF)
and lower sound pressure weighting so as to greatly reduce noise.
In addition, the upper and lower blades can be more flexibly
designed according to the boundary condition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The structure and the technical means adopted by the present
invention to achieve the above and other objects can be best
understood by referring to the following detailed description of
the preferred embodiments and the accompanying drawings,
wherein:
[0018] FIG. 1 is a perspective view of a first embodiment of the
fan impeller structure of centrifugal fan of the present
invention;
[0019] FIG. 2 is a top view of the first embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0020] FIG. 2a is an enlarged view of circled area 2a of FIG.
2;
[0021] FIG. 3 is a bottom view of the first embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0022] FIG. 3a is an enlarged view of circled area 3a of FIG.
3.
[0023] FIG. 4 is a top view of a second embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0024] FIG. 5 is a bottom view of the second embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0025] FIG. 6 is a top view of a third embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0026] FIG. 7 is a bottom view of the third embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0027] FIG. 8 is a top view of a fourth embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0028] FIG. 9 is a bottom view of the fourth embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0029] FIG. 10 is a side view of a fifth embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0030] FIG. 11 is a side view of a sixth embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0031] FIG. 12 is a top view of a seventh embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0032] FIG. 13 is a top view of an eighth embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0033] FIG. 14 is a top view of a ninth embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0034] FIG. 15 is a top view of a tenth embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0035] FIG. 16 is a top view of an eleventh embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0036] FIG. 17 is a top view of a twelfth embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0037] FIG. 18 is a top view of a thirteenth embodiment of the fan
impeller structure of centrifugal fan of the present invention;
[0038] FIG. 19 is a top view of a fourteenth embodiment of the fan
impeller structure of centrifugal fan of the present invention;
and
[0039] FIG. 20 is a top view of a fifteenth embodiment of the fan
impeller structure of centrifugal fan of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0040] Please refer to FIGS. 1, 2, 2a, 3 and 3a. FIG. 1 is a
perspective view of a first embodiment of the fan impeller
structure of centrifugal fan of the present invention. FIG. 2 is a
top view of the first embodiment of the fan impeller structure of
centrifugal fan of the present invention. FIG. 2a is an enlarged
view of circled area 2a of FIG. 2. FIG. 3 is a bottom view of the
first embodiment of the fan impeller structure of centrifugal fan
of the present invention. FIG. 3a is an enlarged view of circled
area 3a of FIG. 3. According to the first embodiment, the fan
impeller structure 1 of centrifugal fan of the present invention
includes a hub 11, a first blade body set 12 and a second blade
body set 13.
[0041] The hub 11 has an extension section 111 having a first side
1111 and a second side 1112. The extension section 111 extends from
the circumference of the hub 11 in a direction away from the hub
11.
[0042] The first blade body set 12 is disposed on the first side
1111. The first blade body set 12 includes multiple first blade
bodies 121. The first blade bodies 121 define therebetween multiple
first air inlets 122 and multiple first air outlets 123. The first
air outlets 123 are arranged at unequal intervals.
[0043] The second blade body set 13 is disposed on the second side
1112. The second blade body set 13 includes multiple second blade
bodies 131. The second blade bodies 131 define therebetween
multiple second air inlets 132 and multiple second air outlets 133.
The second air outlets 133 are arranged at equal intervals.
[0044] The first blade body set 12 extends from the first side 1111
of the extension section 111 in a direction away from the hub 11.
Each first blade body 121 has a first end 1211 and a second end
1212. The first air inlet 122 is defined between the first ends
1211 of each two adjacent first blade bodies 121. The first air
outlet 123 is defined between the second ends 1212 of each two
adjacent first blade bodies 121. The second blade body set 13
extends from the second side 1112 of the extension section 111 in a
direction away from the hub 11. Each second blade body 131 has a
third end 1311 and a fourth end 1312. The second air inlet 132 is
defined between the third ends 1311 of each two adjacent second
blade bodies 131. The second air outlet 133 is defined between the
fourth ends 1312 of each two adjacent second blade bodies 131.
[0045] The first ends 1211 together define a first pitch circle
124. A tangent of the first pitch circle 124 at the first end 1211
is defined as a first tangent 125. The first blade body 121 has a
first blade body central line 1213. A tangent of the first blade
body central line 1213 at the first end 1211 is defined as a second
tangent 126. The second tangent 126 intersects the first tangent
125 to contain a first air incoming angle 12a. The second ends 1212
together define a second pitch circle 127. A tangent of the second
pitch circle 127 at the second end 1212 is defined as a third
tangent 128. A tangent of the first blade body central line 1213 at
the second end 1212 is defined as a fourth tangent 129. The third
tangent 128 and the fourth tangent 129 contain a first air outgoing
angle 12b. The third ends 1311 together define a third pitch circle
134. A tangent of the third pitch circle 134 at the third end 1311
is defined as a fifth tangent 135. The second blade body 131 has a
second blade body central line 1313. A tangent of the second blade
body central line 1313 at the third end 1311 is defined as a sixth
tangent 136. The fifth tangent 135 intersects the sixth tangent 136
to contain a second air incoming angle 13a. The fourth ends 1312
together define a fourth pitch circle 137. A tangent of the fourth
pitch circle 137 at the fourth end 1312 is defined as a seventh
tangent 138. A tangent of the second blade body central line 1313
at the fourth end 1312 is defined as an eighth tangent 139. The
seventh tangent 138 and the eighth tangent 139 contain a second air
outgoing angle 13b. In this embodiment, the first air incoming
angle 12a is larger than or equal to the second air incoming angle
13a.
[0046] The first blade body central line 1213 extends along the
first blade body 121 and has a curvature equal to that of the first
blade body 121. The second blade body central line 1313 extends
along the second blade body 131 and has a curvature equal to that
of the second blade body 131. The first blade body central line
1213 is a longitudinal central line of the thickness of the first
blade body 121. That is, on the basis of the first blade body
central line 1213, the widths extend from the first blade body
central line 1213 to two sides of the first blade body 121 are
equal to each other. Similarly, the second blade body central line
1313 is a longitudinal central line of the thickness of the second
blade body 131. That is, on the basis of the second blade body
central line 1313, the widths extend from the second blade body
central line 1313 to two sides of the second blade body 131 are
equal to each other.
[0047] Please now refer to FIGS. 4 and 5. FIG. 4 is a top view of a
second embodiment of the fan impeller structure of centrifugal fan
of the present invention. FIG. 5 is a bottom view of the second
embodiment of the fan impeller structure of centrifugal fan of the
present invention. The second embodiment is partially identical to
the first embodiment in structure and thus will not be repeatedly
described hereinafter. The second embodiment is different from the
first embodiment in that the first air outgoing angle 12b is
smaller than or equal to the second air outgoing angle 13b.
[0048] Please now refer to FIGS. 6 and 7. FIG. 6 is a top view of a
third embodiment of the fan impeller structure of centrifugal fan
of the present invention. FIG. 7 is a bottom view of the third
embodiment of the fan impeller structure of centrifugal fan of the
present invention. The third embodiment is partially identical to
the first embodiment in structure and thus will not be repeatedly
described hereinafter. The third embodiment is different from the
first embodiment in that the first air incoming angle 12a is
smaller than or equal to the second air incoming angle 13a.
[0049] Please now refer to FIGS. 8 and 9. FIG. 8 is a top view of a
fourth embodiment of the fan impeller structure of centrifugal fan
of the present invention. FIG. 9 is a bottom view of the fourth
embodiment of the fan impeller structure of centrifugal fan of the
present invention. The fourth embodiment is partially identical to
the first embodiment in structure and thus will not be repeatedly
described hereinafter. The fourth embodiment is different from the
first embodiment in that the first air outgoing angle 12b is larger
than or equal to the second air outgoing angle 13b.
[0050] Please now refer to FIG. 10. FIG. 10 is a side view of a
fifth embodiment of the fan impeller structure of centrifugal fan
of the present invention. The fifth embodiment is partially
identical to the first embodiment in structure and thus will not be
repeatedly described hereinafter. The fifth embodiment is different
from the first embodiment in that the second end 1212 has a height
larger than that of the fourth end 1312.
[0051] Please now refer to FIG. 11. FIG. 11 is a side view of a
sixth embodiment of the fan impeller structure of centrifugal fan
of the present invention. The sixth embodiment is partially
identical to the first embodiment in structure and thus will not be
repeatedly described hereinafter. The sixth embodiment is different
from the first embodiment in that the fourth end 1312 has a height
larger than that of the second end 1212.
[0052] Please now refer to FIG. 12. FIG. 12 is a top view of a
seventh embodiment of the fan impeller structure of centrifugal fan
of the present invention. The seventh embodiment is partially
identical to the first embodiment in structure and thus will not be
repeatedly described hereinafter. The seventh embodiment is
different from the first embodiment in that the first blade body
121 has a length larger than that of the second blade body 131.
[0053] Please now refer to FIG. 13. FIG. 13 is a top view of an
eighth embodiment of the fan impeller structure of centrifugal fan
of the present invention. The eighth embodiment is partially
identical to the first embodiment in structure and thus will not be
repeatedly described hereinafter. The eighth embodiment is
different from the first embodiment in that the second blade body
131 has a length larger than that of the first blade body 121.
[0054] Please now refer to FIG. 14. FIG. 14 is a top view of a
ninth embodiment of the fan impeller structure of centrifugal fan
of the present invention. The ninth embodiment is partially
identical to the first embodiment in structure and thus will not be
repeatedly described hereinafter. The ninth embodiment is different
from the first embodiment in that the first end 1211 is aligned
with the third end 1311, while the first and second air outlets
123, 133 are not aligned with each other.
[0055] Please now refer to FIG. 15. FIG. 14 is a top view of a
tenth embodiment of the fan impeller structure of centrifugal fan
of the present invention. The tenth embodiment is partially
identical to the first embodiment in structure and thus will not be
repeatedly described hereinafter. The tenth embodiment is different
from the first embodiment in that the first end 1211 is not aligned
with the third end 1311 and the first and second air inlets 122,
132 are not aligned with each other.
[0056] Please now refer to FIG. 16. FIG. 16 is a top view of an
eleventh embodiment of the fan impeller structure of centrifugal
fan of the present invention. The eleventh embodiment is partially
identical to the tenth embodiment in structure and thus will not be
repeatedly described hereinafter. The eleventh embodiment is
different from the tenth embodiment in that the first end 1211 is
not aligned with the third end 1311 and the first and second air
inlets 122, 132 are not aligned with each other.
[0057] Please now refer to FIG. 17. FIG. 17 is a top view of a
twelfth embodiment of the fan impeller structure of centrifugal fan
of the present invention. The twelfth embodiment is partially
identical to the first embodiment in structure and thus will not be
repeatedly described hereinafter. The twelfth embodiment is
different from the first embodiment in that the number of the first
blade bodies 121 is more than the number of the second blade bodies
131.
[0058] Please now refer to FIG. 18. FIG. 18 is a top view of a
thirteenth embodiment of the fan impeller structure of centrifugal
fan of the present invention. The thirteenth embodiment is
partially identical to the first embodiment in structure and thus
will not be repeatedly described hereinafter. The thirteenth
embodiment is different from the first embodiment in that the
number of the second blade bodies 131 is more than the number of
the first blade bodies 121.
[0059] Please now refer to FIG. 19. FIG. 19 is a top view of a
fourteenth embodiment of the fan impeller structure of centrifugal
fan of the present invention. The fourteenth embodiment is
partially identical to the first embodiment in structure and thus
will not be repeatedly described hereinafter. The fourteenth
embodiment is different from the first embodiment in that the first
air outlets 123 are arranged at equal intervals, while the second
air outlets 133 are arranged at unequal intervals. The
characteristic of this embodiment can be combined with the
characteristics of the second to thirteenth embodiments to achieve
other aspects of the fan impeller structure.
[0060] Please now refer to FIG. 20. FIG. 20 is a top view of a
fifteenth embodiment of the fan impeller structure of centrifugal
fan of the present invention. The fifteenth embodiment is partially
identical to the first embodiment in structure and thus will not be
repeatedly described hereinafter. The fifteenth embodiment is
different from the first embodiment in that the first air outlets
123 are arranged at unequal intervals and the second air outlets
133 are also arranged at unequal intervals. The characteristic of
this embodiment can be combined with the characteristics of the
second to thirteenth embodiments to achieve other aspects of the
fan impeller structure.
[0061] The present invention has been described with the above
embodiments thereof and it is understood that many changes and
modifications in the above embodiments can be carried out without
departing from the scope and the spirit of the invention that is
intended to be limited only by the appended claims.
* * * * *