U.S. patent application number 12/944173 was filed with the patent office on 2012-05-17 for round axial fan with balancing structure.
Invention is credited to Wen-Hao Liu.
Application Number | 20120121410 12/944173 |
Document ID | / |
Family ID | 46047916 |
Filed Date | 2012-05-17 |
United States Patent
Application |
20120121410 |
Kind Code |
A1 |
Liu; Wen-Hao |
May 17, 2012 |
ROUND AXIAL FAN WITH BALANCING STRUCTURE
Abstract
A round axial fan with balancing structure includes a hub; a
ring-shaped band located around an outer side of the hub to thereby
define an annular flow passage between the hub and the ring-shaped
band; a plurality of blades located in the annular flow passage;
and a plurality of recesses circumferentially spaced on and along
the ring-shaped band, each of the recesses internally defining a
receiving space for at least one balancing element to fit therein.
With these arrangements, it is able to achieve weight balance of
the round axial fan for the latter to rotate in a balanced state
and to avoid any vibration due to unbalanced rotation of the round
axial fan.
Inventors: |
Liu; Wen-Hao; (Sinjhuang
City, TW) |
Family ID: |
46047916 |
Appl. No.: |
12/944173 |
Filed: |
November 11, 2010 |
Current U.S.
Class: |
415/220 |
Current CPC
Class: |
F04D 29/326 20130101;
F04D 29/329 20130101; F04D 29/662 20130101 |
Class at
Publication: |
415/220 |
International
Class: |
F04D 29/52 20060101
F04D029/52 |
Claims
1. A round axial fan with balancing structure, comprising: a hub; a
ring-shaped band located around an outer side of the hub to thereby
define an annular flow passage between the hub and the ring-shaped
band; a plurality of blades located in the annular flow passage,
the blades respectively having a radially inner end connected to an
outer circumferential surface of the hub and a radially outer end
connected to an inner circumferential surface of the ring-shaped
band; and a plurality of recesses circumferentially spaced on and
along the ring-shaped band, each of the recesses internally
defining a receiving space for at least one balancing element to
fit therein; whereby a weight distribution of the round axial fan
can be adjusted by fitting the balancing elements in right ones of
the recesses for the round axial fan to rotate in a balanced
state.
2. The round axial fan with balancing structure as claimed in claim
1, further comprising a magnetic ring fitted to an inner
circumferential surface of the hub.
3. The round axial fan with balancing structure as claimed in claim
1, further comprising a central shaft located at a center of the
hub.
4. The round axial fan with balancing structure as claimed in claim
1, wherein the recesses are circumferentially spaced on and along
end faces of the ring-shaped band.
5. The round axial fan with balancing structure as claimed in claim
1, wherein the ring-shaped band has a first end face and a second
end face separately located at two opposite sides of the
ring-shaped band.
6. The round axial fan with balancing structure as claimed in claim
5, wherein the recesses are circumferentially spaced on and along
at least one of the first or/and the second end face of the
ring-shaped band.
7. The round axial fan with balancing structure as claimed in claim
5, wherein a radius of the first end face relative to a center of
the hub is equal to a radius of the second end face relative to the
center of the hub.
8. The round axial fan with balancing structure as claimed in claim
5, wherein a radius of the first end face relative to a center of
the hub is larger than a radius of the second end face relative to
the center of the hub.
9. The round axial fan with balancing structure as claimed in claim
5, wherein a radius of the second end face relative to a center of
the hub is larger than a radius of the first end face relative to
the center of the hub.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a balancing structure, and
more particularly to a round axial fan using such balancing
structure to enable quick adjustment of the weight balance of the
round axial fan, so that the round axial fan can rotate stably and
material and labor costs therefor can be reduced.
BACKGROUND OF THE INVENTION
[0002] Electronic information products, including computers, have
now become very popular among consumers and provide very wide
applications. Consumers' wide demands also lead to rapid technical
development in the electronic information industry. While the
current electronic information products have increasingly upgraded
computing speed and access capacity, the heat produced by the
components in the electronic information products during high-speed
operation thereof also increases. To remove the heat produced by
the components from the electronic information products, heat sinks
and cooling fans are usually provided in the electronic information
products at positions of heat source.
[0003] A round axial fan is one of many different types of cooling
fans. The round axial fan includes a hub, a plurality of blades
radially outward extended from the hub, and a ring-shaped band
integrally connected to the radially outer ends of the blades. The
round axial fan is formed by injection molding. In the process of
injection molding, there are times the injection-molding material
is not uniformly injected to thereby result in uneven weight
distribution of the hub, the blades or the ring-shaped band. The
uneven weight distribution of the hub, the blades or the
ring-shaped band has adverse influence on the balanced rotation of
the round axial fan. That is, when the weight distribution of the
hub, the blades or the ring-shaped band is uneven, the whole round
axial fan would tilt during rotation to result in abrasion and
vibration of the central shaft of the round axial fan relative to
the bearing cup of the base supporting the round axial fan. The
abrasion and vibration of the central shaft not only produces
noise, but also accelerates the fatigue of the central shaft of the
round axial fan to shorten the service life thereof. The fan device
using the round axial fan would have reduced overall quality and
provide poor heat dissipation effect.
[0004] To solve the problem of uneven weight distribution of the
round axial fan, there are manufacturers who try to adjust the
uneven weight distribution by locally providing weights on the hub
of the round axial fan. FIG. 1 is a perspective view showing a
conventional round axial fan with balancing structure. The
conventional round axial fan 70 includes a hub 71 and a ring-shaped
band 72. At least one blade 73 is provided between the hub 71 and
the ring-shaped band 72. A plurality of recesses 711 is formed on
the hub 71, and weights can be fitted in the recesses 711. The
radius of the hub 71 relative to a center of the round axial fan 70
is smaller than the radius of the ring-shaped band 72 relative to
the center of the round axial fan 70. In the case the round axial
fan 70 tilts during rotation due to uneven weight distribution of
the fan 70, weights are directly fitted in correct recesses 711 to
balance the weight distribution of the fan 70. However, since there
is a difference between the radii of the hub 71 and the ring-shaped
band 72, the weights fitted in the recesses 711 on the hub 71 must
be several times as heavy as the ring-shaped band 72 to reach the
required balance. Therefore, the cost for providing the weights on
the hub 71 is high. Further, with the weights fitted on the hub 71,
the round axial fan 70 in rotating is still subject to tilting due
to the uneven weight distribution of the ring-shaped band 72 and
the large radius thereof. As a result, the abrasion and vibration
of the central shaft of the round axial fan 70 relative to the
bearing cup on the base of the fan is increased and requires more
time and labor to adjust the overall weight distribution of the
round axial fan 70.
[0005] In brief, the conventional round axial fan with balancing
structure has the following disadvantages: (1) By fitting the
weights on the hub, increased material for the weights is needed to
achieve the purpose of balancing the fan; (2) the balance achieved
by fitting the weights on the hub is easily adversely affected by
the large radius and the uneven weight distribution of the
ring-shaped band; and (3) additional material and labor costs are
required to adjust the weight distribution of the round axial
fan.
[0006] It is therefore tried by the inventor to develop an improved
round axial fan with balancing structure in order to overcome the
disadvantages in the prior art.
SUMMARY OF THE INVENTION
[0007] A primary object of the present invention is to provide a
round axial fan with balancing structure, so that the round axial
fan can be quickly adjusted to achieve balanced rotation and avoid
damaged blades during rotation of the fan.
[0008] To achieve the above and other objects, the round axial fan
with balancing structure according to the present invention
includes a hub; a ring-shaped band located around an outer side of
the hub to thereby define an annular flow passage between the hub
and the ring-shaped band; a plurality of blades located in the
annular flow passage, the blades respectively having a radially
inner end connected to an outer circumferential surface of the hub
and a radially outer end connected to an inner circumferential
surface of the ring-shaped band; and a plurality of recesses
circumferentially spaced on and along the ring-shaped band, each of
the recesses internally defining a receiving space for at least one
balancing element to fit therein. With these arrangements, it is
able to adjust a weight distribution of the round axial fan for the
latter to rotate in a balanced state.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] 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
[0010] FIG. 1 is a perspective view showing a conventional round
axial fan with balancing structure;
[0011] FIG. 2 is a perspective view showing a round axial fan with
balancing structure according to a first preferred embodiment of
the present invention;
[0012] FIG. 3 is a sectioned side view of FIG. 2;
[0013] FIG. 4 is an exploded sectional view showing the round axial
fan of the present invention is assembled to a base to provide a
fan device;
[0014] FIG. 5 is an assembled view of FIG. 4;
[0015] FIG. 6 is a top perspective view of the fan device of FIG. 5
with a balancing element to be tight-fitted in one of many recesses
formed on the round axial fan;
[0016] FIG. 7 is a sectional view of FIG. 6;
[0017] FIG. 8 is a sectioned side view of a round axial fan with
balancing structure according to a second preferred embodiment of
the present invention;
[0018] FIG. 9 is a sectioned side view of a round axial fan with
balancing structure according to a third preferred embodiment of
the present invention;
[0019] FIG. 10 is a sectioned side view of a round axial fan with
balancing structure according to a fourth preferred embodiment of
the present invention; and
[0020] FIG. 11 is a sectioned side view of a round axial fan with
balancing structure according to a fifth preferred embodiment of
the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] The present invention will now be described with some
preferred embodiments thereof and with reference to the
accompanying drawings. For the purpose of easy to understand,
elements that are the same in the preferred embodiments are denoted
by the same reference numerals.
[0022] Please refer to FIGS. 2 and 3 that are perspective and
sectioned side views, respectively, of a round axial fan with
balancing structure according to a first preferred embodiment of
the present invention. As shown, the round axial fan 10 includes a
hub 20 and a ring-shaped band 30 located around an outer side of
the hub 20 to thereby define an annular flow passage 31 between the
hub 20 and the ring-shaped band 30. The ring-shaped band 30 has a
first end face 32 and a second end face 33 respectively located at
an upper and a lower side of the ring-shaped band 30. A radius of
the first end face 32 relative to a center of the hub 20 may be
larger than, equal to, or smaller than a radius of the second end
face 33 relative to the center of the hub 20. In the illustrated
first preferred embodiment, the radius of the first end face 32
relative to the center of the hub 20 is equal to the radius of the
second end face 33 relative to the center of the hub 20.
[0023] In the annular flow passage 31, there are provided a
plurality of blades 40. The blades 40 are spaced along an outer
circumferential surface of the hub 20, i.e. a surface of the hub 20
facing toward the ring-shaped band 30, to radially outward extend
and connect to an inner circumferential surface of the ring-shaped
band 30, i.e. a surface of the band 30 facing toward the hub 20.
More specifically, the blades 40 each have a radially inner end 41
connected to the outer circumferential surface of the hub 20 and a
radially outer end 42 connected to the inner circumferential
surface of the ring-shaped band 30. A plurality of recesses 34 is
formed on the first end face 32 of the ring-shaped band 30. The
recesses 34 are circumferentially spaced along the first end face
32 and respectively define a receiving space 341 therein.
[0024] Please refer to FIGS. 4 and 5 at the same time. In the first
preferred embodiment, the hub 20 internally defines a rearward
opened hollow space for a magnetic ring 21 to fitly bear on an
inner circumferential surface of the hub 20. A central shaft 22 is
provided in the magnetic ring 21 to locate at a center thereof and
is therefore also located at the center of the hub 20. The round
axial fan 10 can be assembled to a base 50. The base 50 has a
forward extended bearing cup 51 formed thereon for receiving the
central shaft 22 therein, and a stator 52 fitted around an outer
side of the bearing cup 51. The round axial fan 10 is
concentrically assembled to the base 50 with the central shaft 22
serving as a center, so as to complete a fan device.
[0025] When the fan device is supplied with electric current and
turned on, an electromagnetic induction effect between the magnetic
ring 21 on the round axial fan 10 and the stator 52 on the base 50
is produced, bringing the hub 20 and the ring-shaped band 30 to
rotate about the central shaft 22 on the base 50. When the round
axial fan 10 rotates, it guides airflow to move and accordingly
produces air convection to dissipate heat produced by a
heat-producing object.
[0026] Please refer to FIGS. 6 and 7 at the same time. The recesses
34 are circumferentially spaced along the first end face 32 of the
ring-shaped band 30. Each of the recesses 34 internally defines a
receiving space 341 for at least one balancing element 60 to
tightly fit therein. When the round axial fan 10 shows an
unbalanced state and/or vibrates while rotating due to uneven
weight distribution of the hub 20, the ring-shaped band 30 or the
blades 40, at least one balancing element 60 can be tightly fitted
in at least one of the recesses 34 to adjust the weight
distribution of the hub 20, the ring-shaped band 30, or the blades
40, so that the round axial fan 10 can rotate in a balanced state.
Compared to the weight distribution adjustment conducted on the hub
20 in the prior art, the weight distribution adjustment conducted
on the ring-shaped band 30 in the present invention is more
effective because a longer arm of force is available. Therefore,
the purpose of adjusting the weight distribution of the hub 2, the
ring-shaped band 30 or the blades 40 can be achieved with less
number of balancing elements 60 to save the material thereof, and
the condition of a tilted round axial fan 10 during rotation
thereof caused by non-uniform radius and weight distribution of the
hub 20 and the ring-shaped band 30 can be avoided to thereby save
the time and labor for mounting the round axial fan 10.
[0027] By fitting the balancing element or elements 60 in suitable
recess or recesses 34 to accurately adjust the weight distribution
of the hub 20, the ring-shaped band 30 or the blades 40 when there
is any weight difference existing in the hub 20, the ring-shaped
band 30 or the blades 40, the round axial fan 10 can always rotate
in a balanced and stable state to protect the blades 40 from damage
during rotation thereof and to reduce undesired abrasion and
vibration of the components of the round axial fan 10, so as to
extend the usable life of the round axial fan 10.
[0028] FIGS. 8 and 9 are sectioned side views of second and third
preferred embodiments, respectively, of the round axial fan
according to the present invention. In the second preferred
embodiment as shown in FIG. 8, the recesses 34 are provided on the
second end face 33 of the ring-shaped band 30; and in the third
preferred embodiment as shown in FIG. 9, the recesses 34 are
provided on both the first and the second end face 32, 33 of the
ring-shaped band 30. In both cases of the second and third
embodiments, the balancing elements 60 are tight-fitted in the
recesses 34. In the case non-uniform weight distribution is found
in the hub 20, the ring-shaped band 30 or the blades 40, or between
the first and the second end face 32, 33 of the band 30, such
non-uniform weight distribution can be adjusted by fitting at least
one balancing element 60 in at least one of the recesses 34, so
that the round axial fan 10 can rotate in a balanced state.
[0029] The radius of the first end face 32 relative to the center
of the hub 20 can be larger than the radius of the second end face
33 relative to the center of the hub 20 according to actual need,
as a fourth preferred embodiment of the present invention shown in
FIG. 10. In this case, the recesses 34 are formed on the first end
face 32. Alternatively, the radius of the second end face 33
relative to the center of the hub 20 can be larger than the radius
of the first end face 32 relative to the center of the hub 20
according to actual need, as a fifth preferred embodiment of the
present invention shown in FIG. 11. In the latter case, the
recesses 34 are formed on the second end face 33. By suitably
fitting the balancing elements 60 in the right recesses 34, the
weight distribution of the hub 20, the ring-shaped band 30 or the
blades 40 can be adjusted for the whole round axial fan 10 to
rotate in a balanced manner.
[0030] In conclusion, the round axial fan with balancing structure
according to the present invention has the following advantages:
(1) by fitting the balancing elements on the ring-shaped band to
adjust the weight distribution of different components of the round
axial fan, the number of the balancing elements to be used can be
reduced; (2) by fitting the balancing elements on the ring-shaped
band to adjust the weight distribution of different components of
the round axial fan, it is able to avoid adverse influence on the
balance of the round axial fan by the large radius and uneven
weight of the ring-shaped band; (3) material for the balancing
elements can be reduced; (4) cost for mounting the round axial fan
can be reduced; and (5) the service life of the round axial fan can
be prolonged.
[0031] The present invention has been described with some preferred
embodiments thereof and it is understood that many changes and
modifications in the described 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.
* * * * *