Patent Publication Number: US-7717679-B2

Title: Structure of balancing fan

Description:
BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   The present invention generally relates to a structure of a balancing fan, and more particularly to a structure of a fan capable of dynamically balancing rotation of the fan. 
   2. Description of Related Art 
   Referring to  FIG. 1 , the rotation of the fan  21  is not stable due to the manufacturing process, for example, formation of different sizes of the blades  22  and the differential thickness of the hub. These factors directly affect the rotation of the fan  21 . Thus, not only the operation noise is increased but also the rotation efficiency is limited. This may even cause damage to the fan itself. 
   To overcome the above defects, some proposed a hub equipped with a ring side and a top side. The ring side has an upper flange and a lower flange, a lower side and an inner side. The ring side has a plurality of holes aligned correspondingly, and an axle is jointed to the top side. A plurality of blades is disposed around the outer side of the ring side. At least one weight block is securely positioned in the corresponding hole. Thus, the non-uniform weight distribution caused by the different sizes of the blades  22  may be overcome. The weight block is securely positioned in the hole of the lighter part to balance the whole weight of the fan for stabilizing the rotation of the fan. 
   However, the above conventional fan has the holes on the ring side correspondingly, the blades of the fan may have different sizes and the holes may not be positioned corresponding to the lighter blades, and therefore a weight block may be required to be disposed on the lighter side of the fan. Thus, the overall weight of the fan may be over-weighted or insufficient. The user may have to redo the weighing work for effectively using the weight block to overcome the problems due to non-uniform weight distribution, and thus this scheme is substantially unpractical. 
   Accordingly, in the view of the foregoing, how to balance and stabilize the rotation of the fan is an important issue for manufacturers in the field. 
   SUMMARY OF THE INVENTION 
   To overcome the above defects of the conventional art, the present invention provides a structure of a fan. The fan comprises a hub equipped with a rotation balancing unit. The rotation balancing unit comprises a guiding portion with a movable weight member such that the movable weight member moves along with the guiding portion while the hub rotates to balance the rotation of the fan. 
   According to an aspect of the present invention, the non-uniform weight distribution of the fan can be compensated using the movable weight member during the rotation without requiring the weight member. 
   According to another aspect of the present invention, the weight distribution of the fan is controlled to provide the dynamic balance to the rotation of the fan. 
   The fan according to another embodiment of the present invention comprises a hub and a rotation balancing unit. The hub has a top portion and a ring portion. The ring portion is positioned around the top portion. The rotation balancing unit is positioned among the outer side of the top portion and the inner side of the ring portion and has a guiding portion and at least one movable weight member. The movable weight member is positioned on the inner side of the guiding portion such that the movable weight member can move along the guiding portion when the hub rotates to provide a dynamic balancing effect to the rotation of the fan. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     For a more complete understanding of the present invention, reference will now be made to the following detailed description of preferred embodiments taken in conjunction with the following accompanying drawings. 
       FIG. 1  is a sectional side view showing the rotation of the conventional fan. 
       FIG. 2  is a top view of a fan according to a preferred embodiment of the present invention. 
       FIG. 3  is a sectional side view of a fan according to a preferred embodiment of the present invention. 
       FIG. 4  is view showing the installation of the fan into the frame according to a preferred embodiment of the present invention. 
       FIG. 5  is a view showing the installation the fan on the radiator according to a preferred embodiment of the present invention. 
       FIG. 6  is a top view showing the operation of the fan according to a preferred embodiment of the present invention. 
       FIG. 7  is a sectional side view showing the operation of the fan according to a preferred embodiment of the present invention. 
       FIG. 8  is a view showing a guiding portion according to a preferred embodiment of the present invention. 
       FIG. 9  is a view of a guiding portion according to another preferred embodiment of the present invention. 
       FIG. 10  is a view showing a guiding portion according to yet another preferred embodiment of the present invention. 
   

   DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 2 and 3 , the fan  10  comprises a hub  11  and a rotation balancing unit  12 . The hub  11  comprises a top portion  111  and a ring portion  112 . The ring portion  112  is positioned around and jointed to the top portion  111 . The ring portion  112  comprises a plurality of blades  113  extending outwardly from the outer side thereof. 
   The rotation balancing unit  12  is positioned among the top portion  111  and the ring portion  112 . The rotation balancing unit  12  is positioned on the outer side of the top portion  111  as shown in the figure. The rotation balancing unit  12  comprises a guiding portion  121  and a movable weight member  122 . The guiding portion  121  is positioned continuously along the inner side of the top portion  111 . The guiding portion  121  in the present embodiment is comprised of a groove. The guiding portion  121  has one indented side facing the top portion  111  and an elastic hook  1211  formed on another side thereof. The above structure and features are merely for purpose of demonstrating the embodiment of the present invention and is not intended for limiting the scope of the present invention. The opening of the groove may be sealed by a cap (not shown). The movable weight member  122  is positioned in the guiding portion  121 . The movable weight member  122  in the present embodiment may be but no limitedly comprised of a roller ball. Alternatively, the movable weight member  122  may be comprised of a plurality of small sized beads, such as pellets, powder, or liquid. 
   An axle  13  is connected to the inner sidewall of the top portion  111  of the fan  10 , and the axle  13  is fitted into an axial sleeve  141  of the base  14 , as shown in  FIG. 7 . Thus, the fan  10  can be axially and movably positioned on the base  14 . The base  14  may be connected in the frame  15 , as shown in  FIG. 4 , or the base  14  may be connect to the radiator  16 , as shown in  FIG. 5 . Referring to  FIGS. 6 and 7 , when the fan  10  rotates, the movable weight member  122  rotates or moves along with the rotation of the hub  11  and the guiding portion  121 . Thus, when the hub  11  rotates, the movable weight member  122  rotates or moves in the guiding portion  121  such that the weight of the movable weight member  122  may be evenly distributed on the hub  11  and thereby overcome the problem of the non-uniform weight distribution of the fan. Thus, the rotation of the fan  10  may be stabilized. In other words, the problems such as vibration or noise due to non-uniform weight distribution of the fan  10  may be effectively overcome by using the movable weight member  122  of the present invention, wherein the movable weight member  122  rotates or moves in the guiding portion  121  such that the weight of the movable weight member  122  may be evenly distributed on the hub  11  providing dynamic balance for stabilizing the operation of the fan  10 . Thus not only the noise is reduced but also the problems due to non-uniform weight distribution can be overcome. 
   The guiding portion  121  is positioned on the outer side of the top portion  111 , but the positioning of the guiding portion  121  is not limited thereto. Alternatively, the guiding portion  121   b  may also be positioned along the inner sidewall of the top portion  111  as shown in  FIG. 8 . Alternatively, the guiding portion  121   c  may also be positioned along the inner sidewall of the ring portion  112  as shown in  FIG. 9 . 
   Referring to  FIG. 10 , the above guiding portion  121   a  can be a guiding sleeve positioned on the outer sidewall of the top portion  111  of the hub  11 , and the guiding sleeve may enclose the movable weight member  122 . The movable weight member  122  may move along in the guiding sleeve. 
   While the invention has been described in conjunction with a specific best mode, it is to be understood that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations in which fall within the spirit and scope of the included claims. All matters set forth herein or shown in the accompanying drawings are to be interpreted in an illustrative and non-limiting sense.