Patent Publication Number: US-7905708-B2

Title: Fan and impeller thereof

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 094142388 filed in Taiwan, Republic of China on Dec. 2, 2005, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The invention relates to a fan and an impeller thereof and, in particular, to a fan with a reinforced structure and an impeller thereof. 
     2. Related Art 
     Since the present electronic products are rapidly developed towards high performance, high frequency, high speed and more compact, the generated heat of the electronic products becomes greater. However, the electronic products may be unstable in the high temperatures, so that the reliability thereof is affected. Thus, the heat dissipation has become an important issue of the present electronic products. 
     The fan is a common heat dissipating device for the electronic product. As shown in  FIG. 1 , a conventional impeller  10  mainly includes a plurality of blades  101  and a hub  102 . The blades  101  are disposed around the hub  102 , and a connecting ring  12  is used to connect the blades  101 . The hub  102  is used for accommodating a motor (not shown), which drives the impeller  10  to rotate. 
     Since the need for heat dissipation is larger, the performance of the fan must be higher. In general, for increasing the airflow quantity, the size of the blades  101  is enlarged. To maintain the strength of the large-sized blades  101 , the prior art adopts metal blades or adds a circular rib  13  for strengthening the structure of the blades  101 . Herein, the circular rib  13  is disposed around the periphery of the blades  101 . 
     However, the impeller  10  has limited space. In the same capacity, to provide the circular rib  13  makes the blades  101  disposed inwardly, which leads to the reduced active surfaces of blades  101 . Thus, the airflow quantity and the air pressure are decreased. 
     Therefore, it is an important subject to provide a fan and an impeller thereof, which can provide large airflow quantity and have better structure strength. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, the invention is to provide a fan and an impeller thereof that can provide large airflow quantity and have better structure strength. 
     To achieve the above, a fan of the invention comprises an impeller and a motor. The impeller comprises a hub, a plurality of blades and a plurality of reinforced elements. The blades are disposed around the hub and at least one reinforced element is disposed between active surfaces of two adjacent blades. The blades and the reinforced elements are integrally formed as a single piece. The motor connects to the impeller for driving it to rotate. 
     To achieve the above, an impeller of the invention comprises a hub, a plurality of blades and a plurality of reinforced elements. The blades are disposed around the hub and at least one reinforced element is disposed between active surfaces of two adjacent blades. The blades and the reinforced elements are integrally formed as a single piece. 
     As mentioned above, the fan and impeller of the invention have at least one reinforced element on the active surfaces of the adjacent blades. In more detailed, one or more reinforced elements are disposed radially or axially between the adjacent blades. Herein, the reinforced elements can be located in misalignment and be integrally formed as a single piece with the blades to strengthen the structure of the blades. Compared with the prior art, since the reinforced elements are disposed on the active surfaces of the adjacent blades, the blades of the invention are unnecessary to be disposed inwardly under the condition of the same accommodation capacity. Thus, the fan of the invention can have larger blade area for providing larger airflow quantity and air pressure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will become more fully understood from the detailed description given herein below illustration only, and thus is not limitative of the present invention, and wherein: 
         FIG. 1  is a schematic illustration showing a conventional impeller with a circular rib; 
         FIG. 2  is a schematic illustration showing a fan according to an embodiment of the invention; 
         FIG. 3  is a schematic illustration showing an impeller according to an embodiment of the invention; 
         FIG. 4  is a sectional view of an impeller according to an embodiment of the invention; and 
         FIG. 5  is a schematic illustration showing an impeller according to another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements. 
     Referring to  FIG. 2 , a fan  3  according to an embodiment of the invention comprises an impeller  30  and a motor  31 . The fan  3  can be a centrifugal fan but this description is not meant to be construed in a limiting sense. 
     The impeller  30  comprises a hub  301 , a plurality of blades  302  and a plurality of reinforced elements  303 . The blades  302  are disposed around the hub  301 . The blades  302  and the hub  301  can be integrally formed as a single piece. The motor  31  can be accommodated in the hub  301  to drive the impeller  30  to rotate. Besides, the fan  3  may further comprise a fan frame  32 , which has at least one inlet  321  and one outlet  322 . The impeller  30  is accommodated in the fan frame  32 . When the impeller  30  rotates, an airflow is formed to enter from the inlet  321  and exit through the outlet  322 . 
     Referring to  FIG. 3  and  FIG. 4 , the impeller  30  comprises at least one reinforced element  303  on the active surfaces of the adjacent blades  302 . Particularly, a reinforced element  303  (as shown in  FIG. 3 ) can be disposed on the active surfaces of two adjacent blades  302 . Herein, the blades  302  and the reinforced element  303  are integrally formed as a single piece or correspondingly wedged to each other. In this embodiment, the adjacent reinforced elements  303  can be disposed in radial or axial misalignment. The reinforced elements  303  may be a rib without restricted shape and size. Furthermore, the reinforced elements  303  may cross through the blades  302  or may not cross through the blades  302 . 
     In addition, referring to  FIG. 5 , plural reinforced elements  303   a ,  303   b  can be disposed on the active surfaces of the adjacent blades  302 . The reinforced elements  303   a ,  303   b  connecting to the same active surface can be disposed axial misalignment. 
     The impeller  30 ,  30 ′ of the embodiment may further comprise a connecting portion  304 , which connects the blades  302  to the hub  301 . The connecting portion  304  is radially extended from the periphery of the hub  301  outwardly. The blades  302  are fixed to the connecting portion  304 . In the embodiment, the connecting portion  304  is integrally formed as a single piece with the hub  301  and the blades  302 . The connecting portion  304  is an arc structure, a plate structure or a structure with a circular rib. 
     The blades  302  can be made of plastic or metal. In addition, the blades  302  can be plate blades, forward leaning blades or backward leaning blades, and the cross section thereof can be arc, rod-like or wave-shaped. 
     With reference to  FIG. 3  and  FIG. 5 , the blades  302  of the embodiment may further comprise a connecting ring  305  formed on their tops or bottoms to avoid pressure leaking and strengthen the structure. In the embodiment, the connecting ring  305  may be disposed in radial misalignment with the reinforced elements  303  or  303   a.    
     In summary, the fan and impeller of the invention disposes at least one reinforced element on the active surfaces of the adjacent blades. In more detailed, one or more reinforced elements are disposed radially or axially between the adjacent blades. Herein, the reinforced elements can be located in misalignment and be integrally formed as a single piece with the blades to strengthen the structure of the blades. Compared with the prior art, since the reinforced elements are disposed on the active surfaces of the adjacent blades, the blades of the invention are unnecessary to be disposed inwardly under the condition of the same accommodation capacity. Thus, the fan of the invention can have larger blade area for providing larger airflow quantity and air pressure. 
     Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention.