Abstract:
A fan housing for surrounding the rotor of a fan. The fan housing has a first frame and a second frame. The first frame includes at least one extending part with a first engaging member. The second frame includes a guide slot and a second engaging member corresponding to the first engaging member to enable the first and second frames to be detachably assembled together.

Description:
BACKGROUND  
       [0001]     The invention relates to a fan housing, and in particular, to a fan housing provided with engaging members.  
         [0002]      FIG. 1  depicts a conventional fan, wherein the fan  1  has a top cover  12 , a base  13  and a motor  14 . The top cover  12  has through holes  121 . The base  13  has holes  131  corresponding to the through holes  121  of the top cover  12 . Screws  15  pass through the through holes  121  into the holes  131  to join the top cover  12  and the base  13  together.  
         [0003]      FIG. 2  depicts another conventional fan, wherein the fan  2  has a top cover  22 , a base  23  and a motor  24 . The top cover  22  has engaging parts  221 . The base  23  has grooves  231  corresponding to the engaging parts  221  of the top cover  22 . The top cover  22  and the base  23  are joined together with the grooves  231  engaged by the engaging parts  221 .  
         [0004]     The described fans present some significant problems. For the first mentioned fan, the screws  15  joining the top cover  12  and the base  13  may loosen after long-term use. Furthermore, screwing is labor consuming. For the second mentioned fan, the engaging parts  221  engaging the grooves  231  may loosen or even break after long-term use. As a possible result, the fan is not maintained in position and the performance of the electronic device beside the fan is negatively influenced.  
       SUMMARY  
       [0005]     To solve the described problems, the invention provides a fan housing provided with engaging member.  
         [0006]     The fan housing in accordance with an exemplary embodiment of the invention is used to surround a rotor of a fan. The fan housing comprises a first frame and a second frame. The first frame comprises at least one extending part and an engaging hole defined by the extending part. The second frame comprises a guide slot and a protrusion corresponding to the extending part and the engaging hole respectively. The first and second frames are detachably assembled, with the extending part inserted into the guide slot, and the protrusion disposed in the engaging hole. The first frame is a top cover of the fan housing and defines an air inlet. An edge of the air inlet is straight to prevent a backflow in the fan. The second frame is a base of the fan housing, and the first and second frames are assembled via the engaging members to form an air outlet. The second frame comprises an opening serving as an air inlet. The fan is provided with an air inlet or two air inlets. The fan may be a centrifugal fan or an axial fan. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:  
         [0008]      FIG. 1  depicts a conventional fan;  
         [0009]      FIG. 2  depicts another conventional fan;  
         [0010]      FIG. 3  is an exploded perspective view of a fan in accordance with an embodiment of the invention; and  
         [0011]      FIG. 4  is an exploded perspective view of a fan in accordance with another embodiment of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0012]     Referring to  FIG. 3 , a fan  3  in accordance with an embodiment of the invention is a single-intake centrifugal fan which comprises a first frame  31 , a second frame  32 , a stator base  33 , and a rotor  37 .  
         [0013]     The first frame  31  comprises an extending part  311  and an air inlet  314 . The extending part  311  has a first engaging member (e.g. an engaging hole)  312 . The air inlet  314  has a block  315  which is straight to prevent a backflow in the fan  3 . The extending part  311  extends from a periphery of the first frame  31 . The number of the extending parts  311  may be plural. As shown in  FIG. 3 , four extending parts  311  are provided in this embodiment.  
         [0014]     The second frame  32  comprises an air outlet  35  and a guide slot  321  corresponding to the extending part  311  of the first frame  31 . A second engaging member (e.g. a protrusion)  322  is provided on an inner wall  3212  of the guide slot  321 . A plurality of ribs  3211  are provided on both side walls  3213  of the guide slot  321 . The protrusion  322  has an inclined surface  3221 . The guide slot  321  and the protrusion  322  are disposed at an outer surface of the second frame  32 . The number of the guide slots  321  and the protrusions  322  may be plural. As shown in  FIG. 3 , four guide slots  321  and protrusions  322  are provided in this embodiment.  
         [0015]     When the extending part  311  is inserted into the guide slot  321 , the inclined surface  3221  facilitates the protrusion  322  to engage with the engaging hole  312 . Furthermore, ribs  3211  in the guide slot  321  abut the extending part  311  and help relieve excessive strain.  
         [0016]     The first frame  31  in this embodiment is the top cover of the single-intake centrifugal fan  3 , while the second frame  32  is the base. The stator base  33  is disposed in the second frame  32  for receiving an external stator (not shown). The rotor  37  is disposed around the stator base  33  to generate an interaction therebetween. The first frame  31  and the second frame  32  are assembled via the first engaging member  312  and the second engaging member  322  to house the rotor  37 . Airflow enters the air inlet  314  of the first frame  31  and exits from the air outlet  35  of the second frame  32 . The first and second frames  31 ,  32  are both formed by injection molding, pressing or cutting.  
         [0017]      FIG. 4  depicts a dual-intake centrifugal fan  4  in accordance with another embodiment of the invention, wherein the same references will be used for elements which are identical or similar to those shown in  FIG. 3 . In this embodiment, an opening serving as another air inlet  36  is provided on the second frame  32 . Thus, airflow enters the air inlets  314 ,  36  and exits from the air outlet  35 . The second frame  32  further comprises a plurality of connecting parts  34  connecting the stator base  33  and the second frame  32 . The connecting parts  34  also support the stator base  33 . Furthermore, the air inlet  314  has no straight edge.  
         [0018]     It is understood that various fans (e.g. single-intake centrifugal fans, dual-intake centrifugal fans, and axial fans) are applicable to the invention.  
         [0019]     For both the prior art and the invention, the fan housing provides the rotor of the fan with protection. The fan housing of the invention, however, does not have problems presented in the prior art. The invention prevents using screws for joining the frames loosening after long-term use and the process for screwing required. The invention also avoids the potential breakage of the protrusion and the potential loosening of the protrusion. Furthermore, the invention provides ribs to secure the extending part tightly in the guide slot, even if the guide slot is larger than the extending part due to the manufacturing tolerance. In sum, the invention provides strong engaging members, improves the manufacturing speed and saves labor.  
         [0020]     While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.