Patent Publication Number: US-9897094-B2

Title: Axial flow fan

Description:
TECHNICAL FIELD 
     The present disclosure is related to a fan, and more particularly, to an axial flow fan. 
     BACKGROUND 
     When the conventional axial flow fan is assembled, the impeller is mounted in the housing via an opening of the housing. Thus, a maximum outer diameter of the impeller cannot be larger than an inner diameter of the opening. Such structure limits the size of the maximum outer diameter of the impeller and the inner diameter of the opening, the shape of the impeller and the shape of the housing cannot be designed flexibly to suit the practical demand. 
     SUMMARY OF THE INVENTION 
     The present invention provides an axial flow fan. The axial flow fan includes an impeller and a fan frame. The impeller has a maximum outer diameter. The fan frame includes a first body and a second body. The first body includes a plurality of connecting elements and a base. The connecting elements are connected to the base. The second body is a hollow body, and used for disposing around the impeller. The second body includes a flow passage having a minimum inner diameter. The minimum inner diameter of the flow passage is not larger than the maximum outer diameter of the impeller. 
     The axial flow fan of the invention utilizes the first body and the second body to combine to form the fan frame so that the minimum inner diameter of the flow passage is not larger than the maximum outer diameter of the impeller. Therefore, the size of the second body does not restrict the maximum outer diameter of the impeller, and the shape of the impeller and the shape of the fan frame can be designed flexibly according to the practical demand. Furthermore, using a first combining portion and a second combining portion, the first body and the second body can be combined or disassembled. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The details of one or more embodiments of the disclosure are set forth in the accompanying drawings and the description below. Other features and advantages of the disclosure will be apparent from the description, drawings and claims. 
         FIG. 1  is a cross-sectional view of an axial flow fan in accordance with some embodiments. 
         FIG. 2  is an exploded perspective view of a fan frame from a first view angle in accordance with some embodiments. 
         FIG. 3  is a combined perspective view of an axial flow fan from a first view angle in accordance with some embodiments. 
         FIG. 4  is an exploded perspective view of a fan frame from a second view angle in accordance with some embodiments. 
         FIG. 5  is a combined perspective view of an axial flow fan from a second view angle in accordance with some embodiments. 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAIL DESCRIPTION 
       FIG. 1  is a cross-sectional view of an axial flow fan in accordance with some embodiments.  FIG. 2  is an exploded perspective view of a fan frame from a first view angle in accordance with some embodiments.  FIG. 3  is a combined perspective view of an axial flow fan from a first view angle in accordance with some embodiments. Referring to  FIG. 1 ,  FIG. 2  and  FIG. 3 , in an embodiment, the axial flow fan  10  includes an impeller  20  and a fan frame  30 . The impeller  20  has a maximum outer diameter D 1 . In an embodiment, the impeller  20  is a narrow structure on the top and a wide structure on the bottom. The fan frame  30  includes a first body  40  and a second body  50 . The first body  40  includes a plurality of connecting elements  401  and a base  402 . The connecting elements  401  are connected to the base  402 . In an embodiment, the connecting elements  401  can be static blades or connecting ribs. The second body  50  is a hollow body, and used for disposing around the impeller  20 . The second body  50  includes a flow passage  60  having a minimum inner diameter D 2 . The minimum inner diameter D 2  of the flow passage  60  is not larger than the maximum outer diameter D 1  of the impeller  20 . 
     That is, the second body  50  is a narrow structure on the top and a wide structure on the bottom, and the minimum inner diameter D 2  is on the top of the second body  50 . Because the minimum inner diameter D 2  of the flow passage  60  is not larger than the maximum outer diameter D 1  of the impeller  20 , the impeller  20  cannot be mounted from the top of the second body  50 . Thus, the impeller  20  is mounted on the base  402  of the first body  40  firstly, then the second body  50  is mounted around the impeller  20 . The second body  50  and the first body  40  combine to form the axial flow fan  10 . 
     The axial flow fan  10  of the invention utilizes the first body  40  and the second body  50  to combine to form the fan frame  30  so that the minimum inner diameter D 2  of the flow passage  60  is not larger than the maximum outer diameter D 1  of the impeller  20 . Therefore, the size of the second body  50  does not restrict the maximum outer diameter D 1  of the impeller  20 , and the shape of the impeller  20  and the shape of the fan frame  30  can be designed flexibly according to the practical demand. 
     The first body  40  further includes a first side wall  41 , a first edge  42  and at least one first combining portion  43 ,  44 . The first edge  42  is formed on the first side wall  41 . The at least one first combining portions  43 ,  44  are formed on the first edge  42 , and extend along the first side wall  41  and the first edge  42 . In an embodiment, the first body  40  includes four first combining portions  43 ,  44 . Two first combining portions  43  are the same structures, and two first combining portions  44  are the same structures. 
     The second body  50  includes a second side wall  51 , a second edge  52  and at least one second combining portion  53 ,  54 . The second edge  52  is formed under the second side wall  51 . The at least one second combining portions  53 ,  54  are formed on the second edge  52 , and extend along the second side wall  51  and the second edge  52 . The disposing places of the at least one second combining portion  53 ,  54  are corresponding to those of the at least one first combining portion  43 ,  44  so as to combine the at least one first combining portion  43 ,  44  and the at least one second combining portion  53 ,  54 , respectively. In an embodiment, the second body  50  includes four second combining portions  53 ,  54 . Two second combining portions  53  are the same structures, and are corresponding to the two first combining portions  43 . Two second combining portions  54  are the same structures, and are corresponding to the two first combining portions  44 . 
     The second edge  52  defines a first opening  55 . An inner diameter D 3  of the first opening  55  is larger than the maximum outer diameter D 1  of the impeller  20 . As stated in the above, the impeller  20  is mounted on the base  402  of the first body  40  firstly, then via the first opening, the second body  50  is mounted around the impeller  20  so as to smoothly assemble the impeller  20  and the second body  50 . 
     In an embodiment, the first combining portion  43  includes a first extending portion  431  extending along the first side wall  41  and the first edge  42 . That is, the first extending portion  431  extends along a peripheral direction of the first side wall  41 . A first guiding slot  436  is defined between the first extending portion  431  and the first edge  42 . The second combining portion  53  includes a limiting protrusion  531  extending along the second side wall  51  and the second edge  52 . By appropriate positioning, the second body  50  is disposed on the first body  40 , and a force is exerted appropriately to rotate the first body  40  or the second body  50  so that the limiting protrusion  531  is mounted in the first guiding slot  436 , and the first extending portion  431  is disposed on the limiting protrusion  531  so as to combine the first body  40  and the second body  50 . 
     The first extending portion  431  includes a first positioning recess  432  formed on the inner wall of the first extending portion  431 . The second combining portion  53  further includes a first positioning protrusion  532  formed above the limiting protrusion  531 . The disposing place of the first positioning protrusion  532  is corresponding to that of the first positioning recess  432 , and the shape of the first positioning protrusion  532  is corresponding to that of the first positioning recess  432 . Therefore, after the limiting protrusion  531  is mounted in the first guiding slot  436 , the first positioning protrusion  532  is mounted in the first positioning recess  432  to position and combine the first body  40  and the second body  50 . 
     The first extending portion  431  further includes a first positioning hook  433  extending downward. The limiting protrusion  531  includes a second positioning hook  533  extending upward. After the limiting protrusion  531  is mounted in the first guiding slot  436 , the first positioning hook  433  is disposed outside of the second positioning hook  533  so that the first positioning hook  433  and the second positioning hook  533  are locked and positioned each other to further position and combine the first body  40  and the second body  50 . 
     The first combining portion  43  further includes a second positioning protrusion  434  disposed on an inner side of the first side wall  41 , and extending inward. The second combining portion  53  further includes a second extending portion  534  formed on the second edge  52  and extending downward. The second extending portion  534  includes a second guiding slot  535 . The disposing place of the second extending portion  534  is corresponding to that of the second positioning protrusion  434 , and the shape of the second positioning protrusion  434  is corresponding to that of the second guiding slot  535 . Therefore, when the limiting protrusion  531  is mounted in the first guiding slot  436 , on the inner side of the first side wall  41 , the second positioning protrusion  434  is mounted in the second guiding slot  535  so as to further position and combine the first body  40  and the second body  50 . 
     Using the above structures of the first combining portion  43  and the second combining portion  53 , the first body  40  and the second body  50  can be combined smoothly. After the first body  40  and the second body  50  are assembled, the first body  40  and the second body  50  can be disassembled by an exerted force appropriately to rotate the first body  40  and the second body  50  in a reverse direction. Thus, the first body  40  and the second body  50  can be disassembled, and the structures of the first combining portion  43  and the second combining portion  53  will not be broken. 
     Because the structure of the first combining portion  43  is different from that of the first combining portion  44 , and the structure of the second combining portion  53  is different from that of the second combining portion  54 , the first combining portion  44  and the second combining portion  54  are shown from different view angle.  FIG. 4  is an exploded perspective view of a fan frame from a second view angle in accordance with some embodiments.  FIG. 5  is a combined perspective view of an axial flow fan from a second view angle in accordance with some embodiments. Referring to  FIG. 4  and  FIG. 5 , with reference to the structures in the first combining portion  43  and the second combining portion  53  shown in  FIG. 2  and  FIG. 3 , similar components in the first combining portion  44  and the second combining portion  54  are labeled with the same component numbers. The first combining portion  44  further includes a third positioning protrusion  441  disposed on an inner side of the first side wall  41 , and extending inward. The disposing level of the third positioning protrusion  441  is the same as that of the first extending portion  431 . The second combining portion  54  further includes a second positioning recess  541 . The second positioning recess  541  includes an inlet and a turning area. After the third positioning protrusion  441  enters into the second positioning recess  541  via the inlet of the second positioning recess  541 , a force is exerted appropriately to rotate the first body  40  or the second body  50  so that the third positioning protrusion  441  is mounted in the second positioning recess  541  so as to further position and combine the first body  40  and the second body  50 . 
     Using the structure of the third positioning protrusion  441  and the second positioning recess  541 , the first body  40  and the second body  50  can be combined and assembled only from a specific position so as to prevent the mistake during assembling and to improve the assembling efficiency and quality. 
     While the embodiment of the present invention have been illustrated and described, various modifications and improvements can be made by those skilled in the art. The embodiments of the present invention are therefore described in an illustrative but not restrictive sense. It is intended that the present invention may not be limited to the particular forms as illustrated, and all modifications that maintain the spirit and scope of the present invention are within the scope as defined in the appended claims.