ROUND AXIAL FAN WITH BALANCING STRUCTURE

A round axial fan with balancing structure includes a hub, a ring-shaped band located around an outer side of the hub, and a plurality of blades extended between the hub and the ring-shaped band. At least one removable area is defined on the ring-shaped band for serving as a balancing area. By determining and removing one or more balancing areas at appropriate locations from the ring-shaped band, uneven weight distribution of the components of the round axial fan can be adjusted to enable stable rotation of the fan without producing vibration. The provision of the balancing area on the ring-shaped band of the round axial fan also enables reduced material and labor costs for adjusting the weight distribution of the fan.

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Description
FIELD OF THE INVENTION

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 distribution of the round axial fan, so that the round axial fan can rotate stably and the material and labor costs for balancing the fan can be reduced.

BACKGROUND OF THE INVENTION

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.

Cooling fans can be generally divided into two types, namely, axial fans and centrifugal fans. A round axial fan is one type of the axial 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.

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 10 includes a hub 11 and a ring-shaped band 12. At least one blade 13 is provided between the hub 11 and the ring-shaped band 12. The radius of the hub 11 relative to a center of the round axial fan 10 is smaller than the radius of the ring-shaped band 12 relative to the center of the round axial fan 10. At least one recess 111 is formed on the hub 11. In the case the round axial fan 10 tilts during rotation due to uneven weight distribution of the fan 10, weights are directly fitted in correct recesses 111 to balance the weight distribution of the fan 10. However, since there is a difference between the radii of the hub 11 and the ring-shaped band 12, the weights fitted in the recesses 111 on the hub 11 must be several times as heavy as the ring-shaped band 12 to reach the required balance. Therefore, the cost for providing the weights on the hub 11 is high. Further, with the weights fitted on the hub 11, the round axial fan 10 in rotating is still subject to tilting due to the uneven weight distribution of the ring-shaped band 12 and the large radius thereof. As a result, the abrasion and vibration of the central shaft of the round axial fan 10 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 10.

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.

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

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 weight distribution and accordingly stable rotation thereof.

Another object of the present invention is to provide a round axial fan with balancing structure, so that material and labor costs for adjusting the weight distribution of the round axial fan can be reduced.

A further object of the present invention is to provide a round axial fan with balancing structure, in which a shielding member is attached to at least one balancing area provided on the fan, so that the function of the round axial fan to produce airflow is not adversely affected by the balancing area when the same is removed from the fan to balance the weight distribution of the fan.

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 at least one removable area defined on the ring-shaped band for serving as a balancing area. By determining and removing one or more balancing areas at appropriate locations from the ring-shaped band, it is able to adjust an overall weight distribution of the round axial fan for the same to rotate stably.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 1 is a perspective view showing a conventional round axial fan with balancing structure;

FIG. 2 is a top perspective view showing a round axial fan with balancing structure according to a first preferred embodiment of the present invention;

FIG. 3 is a bottom perspective view of the round axial fan with balancing structure according to the first preferred embodiment of the present invention;

FIG. 4 is a sectioned side view of the round axial fan with balancing structure according to the first preferred embodiment of the present invention;

FIG. 5A is a sectioned side view of a round axial fan with balancing structure according to a second preferred embodiment of the present invention;

FIG. 5B is a sectioned side view of a round axial fan with balancing structure according to a third preferred embodiment of the present invention;

FIG. 6A is a top perspective view showing a round axial fan with balancing structure according to a fourth preferred embodiment of the present invention;

FIG. 6B is a bottom perspective view of the round axial fan with balancing structure according to the fourth preferred embodiment of the present invention; and

FIG. 6C is a sectioned side view of the round axial fan with balancing structure according to the fourth preferred embodiment of the present invention.

 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described with some preferred embodiments thereof and with reference to the accompanying drawing. For the purpose of easy to understand, elements that are the same in the preferred embodiments are denoted by the same reference numerals.

Please refer to FIGS. 2, 3 and 4 that are front perspective, rear 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 20 includes a hub 30 and a ring-shaped band 40 located around an outer side of the hub 30 to thereby define an annular flow passage 31 between the hub 30 and the ring-shaped band 40. The ring-shaped band 40 has a first end face 41 and a second end face 42 respectively located at an upper and a lower side of the ring-shaped band 40. A radius of the first end face 41 relative to a center of the hub 30 may be larger than, equal to, or smaller than a radius of the second end face 42 relative to the center of the hub 30. In the illustrated first preferred embodiment, the radius of the first end face 41 relative to the center of the hub 30 is equal to the radius of the second end face 42 relative to the center of the hub 30.

In the annular flow passage 31, there is provided a plurality of blades 50. The blades 50 each have a radially inner end 51 connected to an outer circumferential surface of the hub 30 and a radially outer end 52 connected to an inner circumferential surface of the ring-shaped band 40. The blades 50 in rotating are able to guide airflow to move, so as to produce air convection to carry away heat produced by a heat-producing element. On the ring-shaped band 40, there is defined at least one removable area that can be removed from the ring-shaped band 40 to serve as a balancing area 60. A shielding member 61 is attached to an outer surface of the at least one balancing area 60 provided on the ring-shaped band 40, so as to effectively stop airflow from entering into a void at the balancing area 60 when it is removed from the ring-shaped band 40.

The at least one balancing area 60 is defined on the ring-shaped band 40 for adjusting uneven eight distribution of the round axial fan 20 when the same shows an unbalanced state and/or vibrates while rotating due to uneven weight distribution of the hub 30, the ring-shaped band 40 or the blades 50, or between the first end face 41 and the second end face 42 of the ring-shaped band 40. The at least one balancing area 60 may be defined on the first end face 41 of the ring-shaped band 40, as shown in FIG. 2; or be defined on the second end face 42 of the ring-shaped band 40, as shown in FIG. 3; or be defined on both of the first and the second end 41, 42 of the ring-shaped band 40, as shown in FIG. 4. In the illustrated first preferred embodiment, when uneven weight distribution of the hub 30, the ring-shaped band 40 or the blades 50, or between the first end face 41 and the second end face 42 of the ring-shaped band 40 is found, one or more of the at least one balancing area 60 at appropriate positions are removed from the ring-shaped band 40 to form one or more holes thereon, so as to adjust the weight distribution of the hub 30, the ring-shaped band 40 or the blades 50, allowing the round axial fan 20 to be quickly adjusted for rotating in a balanced state. By performing the weight distribution adjustment on the ring-shaped band 40 instead of the hub 30, the number of required balancing areas 60 can be effectively reduced to achieve the purpose of saving the labor and material costs for adjusting the weight distribution of different components of the round axial fan 20. Further, the condition of a tilted round axial fan 20 during rotation thereof caused by non-uniform radius and weight distribution of the hub 30 and the ring-shaped band 40 can be avoided to enable further saving of the material and labor costs.

FIG. 5A is a sectioned side view of a round axial fan with balancing structure according to a second preferred embodiment of the present invention. In the second preferred embodiment, a radius of the first end face 41 relative to a center of the hub 30 can be larger than a radius of the second end face 42 relative to the center of the hub 30 according to actual need, and the at least one balancing area 60 is defined on the first end face 41. Alternatively, according to a third preferred embodiment of the present invention as shown in FIG. 5B, the radius of the second end face 42 relative to the center of the hub 30 can be larger than the radius of the first end face 41 relative to the center of the hub 30 according to actual need, and the at least one balancing area 60 is defined on the second end face 42. By determining and removing one or more balancing areas 60 at appropriate locations from the ring-shaped band 40, the uneven weight distribution of the hub 30, the ring-shaped band 40 or the blades 50, or between the first end face 41 and the second end face 42 of the ring-shaped band 40 can be adjusted for the whole round axial fan 20 to rotate in a balanced manner.

FIGS. 6A, 6B and 6C illustrate a fourth preferred embodiment of the present invention. Since the components and the connection relation therebetween in the fourth embodiment are generally similar to those in the previous embodiments, they are not repeatedly described herein. However, the fourth embodiment is different from the previous embodiments in that the first end face 41 and the second end face 42 include a first radially outward extended end flange 411 and a second radially outward extended end flange 421, respectively; and the at least one balancing area 60 is defined on the first end flange 411 at the first end face 41 of the ring-shaped band 40 as shown in FIG. 6A, or on the second end flange 421 at the second end face 42 of the ring-shaped band 40 as shown in FIG. 6B, or on both of the first and the second end flange 411, 421 at the first and the second end face 41, 42 of the ring-shaped band 40, respectively, as shown in FIG. 6C. When the balancing area 60 is removed from the first and/or the second end flange 411, 421 for the purpose of adjusting the weight distribution of the hub 30, the ring-shaped band 40 or the blades 50, or between the first end face 41 and the second end face 42 of the ring-shaped band 40, a notch is formed on the first and/or the second end flange 411, 421 to achieve the same function of adjusting the overall weight distribution of the round axial fan 20 for the same to rotate in a balanced manner.

In conclusion, the round axial fan with balancing structure according to the present invention has the following advantages: (1) by defining the balancing area or areas on the ring-shaped band, the labor and material costs required to adjust the weight distribution of different components of the round axial fan can be reduced; (2) by defining the balancing area or areas 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) the material needed for balancing the round axial fan can be saved; (4) the labor cost for balancing the round axial fan can be reduced; and (5) the service life of the round axial fan can be prolonged.

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.

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 at least one removable area defined on the ring-shaped band for serving as a balancing area; whereby, by determining and removing one or more balancing areas at appropriate locations from the ring-shaped band, an overall weight distribution of the round axial fan can be adjusted to enable stable rotation of the fan.

2. 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.

3. The round axial fan with balancing structure as claimed in claim 2, wherein the first end face and the second end face include a first and a second radially outward extended end flange, respectively.

4. The round axial fan with balancing structure as claimed in claim 2, wherein the at least one balancing area is provided on the first end face.

5. The round axial fan with balancing structure as claimed in claim 2, wherein the at least one balancing area is provided on the second end face.

6. The round axial fan with balancing structure as claimed in claim 2, wherein the at least one balancing area is provided on both of the first and the second end face.

7. The round axial fan with balancing structure as claimed in claim 3, wherein the at least one balancing area is provided on the first end flange at the first end face, and a notch is formed on the first end flange when the balancing area is removed therefrom.

8. The round axial fan with balancing structure as claimed in claim 3, wherein the at least one balancing area is provided on the second end flange at the second end face, and a notch is formed on the second end flange when the balancing area is removed therefrom.

9. The round axial fan with balancing structure as claimed in claim 3, wherein the at least one balancing area is provided on both of the first and the second end flange at the first and the second end face, respectively; and a notch is formed on each of the first and the second end flange when the balancing area is removed therefrom.

10. The round axial fan with balancing structure as claimed in claim 2, 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.

11. The round axial fan with balancing structure as claimed in claim 2, 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.

12. The round axial fan with balancing structure as claimed in claim 2, 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.

13. The round axial fan with balancing structure as claimed in claim 1, further comprising a shielding member attached to an outer surface of the at least one balancing area.

Patent History
Publication number: 20120219419
Type: Application
Filed: Feb 28, 2011
Publication Date: Aug 30, 2012
Inventor: Wen-Hao Liu (New Taipei City)
Application Number: 13/036,649
Classifications
Current U.S. Class: With Weight-balancing Means (416/144)
International Classification: F01D 25/04 (20060101);