Patent Publication Number: US-8113774-B2

Title: Fan frame and heat dissipation fan incorporating the fan frame

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to fan frames, and more particularly to a new and improved fan frame for use in connection with a heat dissipation fan which typically intends for dissipating heat from electronic components. 
     2. Description of Related Art 
     A typical heat dissipation fan generally comprises a fan frame, and a stator and a rotor received in the fan frame. The fan frame incorporated in the heat dissipation fan generally includes a bracket, a central tube and a plurality of ribs. The central tube locates in a center of the bracket for installing the rotor and the stator thereon. The ribs interconnect the central tube with the bracket for fastening the central tube in place. The bracket, the central tube and the ribs are integrally molded to form the fan frame. 
     However, such integrally molded structure of the fan frame has many disadvantages. As the fan develops, some parts of the fan frame of the fan need special features to meet special requirements; for example, the central tube and the ribs require a high strength while the bracket does not. However, because the bracket, the central tube and the ribs are integrally molded, the fan frame needs to be wholly molded by a material having a high strength to satisfy the special requirement of the central tube and the ribs. This results in a high cost of the fan frame. When some parts of the fan frame are damaged and need to be replaced, the whole fan frame must be replaced due to the integrity of the fan frame, which results in a high maintenance cost for the fan incorporating the fan frame. Additionally, a fan which incorporates a fan frame having a large air inlet can produce a large amount of airflow, and a fan which incorporates a fan frame having a small air outlet can produce a high air pressure. However, when there is a requirement to replace a fan with a large amount of airflow with a fan with a high air pressure or vice versa, the original fan must be totally discarded; this also increases the cost. 
     What is needed, therefore, is a new fan frame of a heat dissipation fan which can overcome the above-mentioned disadvantages. 
     SUMMARY 
     The present invention relates to a fan frame. According to an exemplary embodiment of the present invention, the fan frame includes a bracket and a base. The bracket includes a sidewall, an air inlet defined in a top side of the sidewall and an opposite air outlet defined in a bottom side of the sidewall. The sidewall defines a plurality of first locking units thereon. The base includes a main body, a plurality of ribs and a plurality of second locking units. Each rib has a fixed end connected with the main body and an opposite free end. Each second locking unit is formed at the free end of a corresponding rib. The second locking units are detachably interlocked with the first locking units to mount the base to the bracket to thereby form the fan frame. The base and the bracket are made of different materials, wherein the material for forming the base has a strength higher than that for forming the bracket. 
     The present invention relates, in another aspect, to a heat dissipation fan. According to an embodiment of the present invention, the heat dissipation fan includes a fan frame, a stator a stator mounted to the base and received in the fan frame and a rotor rotatable with respect to the stator. The fan frame includes a bracket and a base. The bracket includes a sidewall, an air inlet defined in a top side of the sidewall and an opposite air outlet defined in a bottom side of the sidewall. The sidewall defines a plurality of first locking units thereon. The base includes a main body, a plurality of ribs and a plurality of second locking units. Each rib has a fixed end connected with the main body and an opposite free end. Each respective second locking unit is formed at the free end of each respective rib. The second locking units are detachably interlocked with the first locking units to mount the base to the bracket. 
     Other advantages and novel features of the present invention will become more apparent from the following detailed description of embodiment when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  an assembled, isometric view showing a heat dissipation fan in accordance with a first exemplary embodiment of the present invention; 
         FIG. 2  is an exploded, isometric view of the heat dissipation fan of  FIG. 1 ; 
         FIG. 3  is an isometric view of a fan frame of the heat dissipation fan of  FIG. 1 ; 
         FIG. 4  is a cross-section view of the fan frame of  FIG. 3 ; 
         FIG. 5  is an assembled, isometric view showing a heat dissipation fan in accordance with a second exemplary embodiment of the present invention; 
         FIG. 6  is an exploded, isometric view of the heat dissipation fan of  FIG. 5 ; 
         FIG. 7  is an isometric view of a fan frame of the heat dissipation fan of  FIG. 5 ; and 
         FIG. 8  is a cross-section view of the fan frame of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Reference will now be made to the drawings to describe the various present embodiments in detail. 
     Referring to  FIG. 1  and  FIG. 2 , a heat dissipation fan according to an exemplary embodiment includes a rotor  40 , a stator  30  in respective to which the rotor  40  is rotatable, and a fan frame  20  receiving the rotor  40  and the stator  30  therein. 
     The fan frame  20  comprises a rectangular bracket  22  and a base  24  detachably mounted on a bottom side of the bracket  22 . 
     Referring to  FIG. 3 , the bracket  22  comprises a top plate  221 , an opposite bottom plate  223  and a sidewall  225  interconnecting the top plate  221  with the bottom plate  223 . The top plate  221  extends horizontally outwardly from a top end of the sidewall  223 . The bottom plate  223  extends horizontally outwardly from a bottom end of the sidewall  223 . The bracket  22  is molded by plastic material, and includes an air inlet  228  and an air outlet  229 . The air inlet  228  and the air outlet  229  are located at opposite sides of the bracket  22 , wherein the air inlet  228  is defined in a central portion of the top plate  221 , and the air outlet  229  is defined in a central portion of the bottom plate  223 . Four mounting holes  226  are defined in four corners of the top plate  221  and four corners of the bottom plate  223  respectively. The sidewall  225  interconnects an inner periphery of the top plate  221  and an inner periphery of the bottom plate  223 . The sidewall  225  includes a top portion  225   a , a bottom portion  225   b  and a middle portion  225   c  interconnecting the top portion  225   a  with the bottom portion  225   b . The top portion  225   a  and the bottom portion  225   b  of the sidewall  225  each have an inner diameter larger than an inner diameter of the middle portion  225   c  of the sidewall  225 . Four first locking units  227  are formed on the sidewall  225  near the four corners of the top plate  221  and the bottom plate  223  respectively. Each of the first locking units  227  comprises a block  2273  formed on the middle portion  225   c  of the sidewall  225 , a first hole  2271  defined on the top portion  225   a  of the sidewall  225  and a second hole  2272  defined on the bottom portion  225   b  of the sidewall  225 . As shown in  FIG. 4 , a plurality of recesses  222  are defined in a bottom surface of the bottom plate  223  and surround the air outlet  229 . Each of the recesses  222  communicates with a corresponding second hole  2272  of the first locking unit  227 . 
     Referring back to  FIG. 2 , in the present embodiment, the base  24  is formed from a different material based on the designed strength requirement, such as metal or fiber-reinforced plastic. The material for forming the base  24  has a strength higher than that for forming the bracket  22 . The base  24  comprises a circular main body  240 , a central tube  243  extending upwardly from a top surface of the main body  240  and a plurality of ribs  242  extending outwardly from a periphery of the main body  240 . Each of the ribs  242  has a fixed end  2421  connected with the main body  240 , and an opposite free end  2422 . A plurality of second locking units  245  are formed on the free ends  2422  of the ribs  242  in one-to-one manner. Each of the second locking units  245  comprises a pole  2451 , a hook  2452  and a nub  2453 . The pole  2451  extends upwardly and perpendicularly from the free end  2422  of the corresponding rib  242 . Each of the poles  2451  has a size substantially equals to a size of the second hole  2272  of the first locking unit  227 . Each of the hooks  2452  extends inwardly from a top end of the pole  2451  towards the central tube  243 . An inclined guiding surface  2456  is formed on a top surface of the hook  2452 . A receiving trough  2455  is formed on an inner side surface of the pole  2451  immediately below the hook  2452  and faces to the central tube  243 . The receiving trough  2455  is configured for receiving a corresponding block  2273  of the first locking unit  227  therein. Each of the nubs  2453  extends outwardly and horizontally from the free end  2422  of the corresponding rib  242 . The nub  2453  has a shape and a size substantially similar to the shape and the size of the recess  222  of the bottom plate  223  of the bracket  22 . 
     Referring also to  FIG. 4 , in assembly, the base  24  is placed at a bottom side of the bracket  22  with the second locking units  245  of the base  24  aligned with the first locking units  227  of the bracket  22 . The base  24  is pressed towards the bracket  22  until the poles  2451  extend through the second holes  2272  of the first locking units  227  and the hooks  2452  engage in the first holes  2271  of the first locking units  22 . Meanwhile, each nub  2453  is received in the corresponding recess  222  and abuts against the bottom plate  223  of the bracket  22 . Finally, the stator  30  is mounted around the central tube  243 , and the rotor  40  is rotatably disposed around the stator  30 . A shaft (not shown) of the rotor  40  extends downwardly through a bearing (not shown) which has been mounted in the central tube  243  beforehand. 
     In assembly of the present fan frame  20 , each hook  2452  of the second locking unit  245  of the base  24  firstly is elastically deformed by the corresponding block  2273  of the first locking unit  227  when traveling from the second hole  2272  towards the first hole  2271 , and then returns to its original state to protrude inwardly in the first hole  2271  after traveling through the corresponding block  2273 . The corresponding block  2273  is engaged in the receiving trough  2455  formed adjacent to a bottom of the hook  2452 , thereby securely mounting the base  24  to the bracket  22 . 
     In the present embodiment, the fan frame  20  is comprised of two parts, i.e., the bracket  22  and the base  24 . When one part of the fan frame  20  is damaged and needs to be replaced or repaired, the hooks  2452  of the second locking units  245  of the base  24  are caused to disengage from the first holes  2271  of the first locking units  227 . Then, the base  24  is dismounted from the bracket  22 . Therefore, the base  24  is separated from the bracket  22 . The damaged bracket  22  or base  24  can be replaced by another new bracket  22  or base  24 . Furthermore, according to the requirement, the base  24  can be assembled with another bracket  22  having a larger air inlet to form a new fan frame in order to increase the amount of airflow of the heat dissipation fan incorporating the fan frame. Alternatively, the base  22  can be assembled to another bracket  22  having a smaller air outlet to form another fan frame in order to increase the air pressure of the heat dissipation fan incorporating the fan frame. 
       FIG. 5  and  FIG. 6  show a heat dissipation fan according to a second embodiment. The heat dissipation fan comprises a fan frame  20   a , and two stators  30  and two rotors  40  received in the fan frame  20   a . The stators  30  and the rotors  40  are arranged symmetrically at top side and bottom side of the fan frame  20   a , respectively. Each of the stators  30  and each of the rotors  40  have substantially the same configurations as the stator  30  and the rotor  40  of the previous first embodiment. 
     The fan frame  20   a  comprises a bracket  22  and a base  24   a  detachably mounted on a waist position of the bracket  22 . 
     Referring also to  FIG. 7  and  FIG. 8 , the bracket  22  comprises a top plate  221 , a bottom plate  223  and a sidewall  225  interconnecting the top plate  221  with the bottom plate  223 . The sidewall  225  has a higher height than the sidewall  225  of the first embodiment. A plurality of first locking units  227  are formed on the sidewall  225  of the bracket  22 . As similar to the first embodiment, each of the first locking units  227  comprises a block  2273 , and a first hole  2271  and a second hole  2272  defined on a top side and a bottom side of the block  2273  respectively. The block  2273  is located at a position above the middle portion  225   c  of the sidewall  225 . 
     The base  24   a  comprises a circular main body  240 , two central tubes  243  extending oppositely from a top surface and a bottom surface of the main body  243  respectively, and a plurality of ribs  242  extending outwardly from a periphery of the main body  240 . Each of the ribs  242  comprises a fixed end  2421  connected with the main body  240 , and an opposite free end  2422 . A plurality of second locking units  245   a  are formed on the free ends  2422  of the ribs  242  respectively. Each of the second locking units  245   a  comprises a pole  2451   a  extending upwardly and perpendicularly from the free end  2422  of the rib  242 , a hook  2452   a  extending inwardly from a top end of the pole  2451   a , and a fixing post  2454   a  extending downwardly and perpendicularly from the free end  2422  of the rib  242 . A receiving trough  2455   a  is formed on an inner side surface of the pole  2451  and faces to the central tube  243 . The receiving trough  2455  is located just under the hook  2452   a , and is configured for receiving a corresponding block  2273  of the first locking unit  227  therein. 
     During assembly, the base  24   a  is placed at a bottom side of the bracket  22  with the second locking units  245   a  of the base  24   a  pointing to the first locking units  227  of the bracket  22 . The base  24   a  is pressed towards the bracket  22  until the poles  2451   a  extend through the second holes  2272  of the first locking units  227  and the hooks  2452   a  engage in the first holes  2271  of the first locking units  227 . The blocks  2273  of the first locking units  227  engage in the receiving troughs  2455   a  of the second locking units  245   a . Simultaneously, each post  2454   a  is received in the second hole  2272  of the corresponding first locking unit  227  and abuts against the bottom portion  225   b  of the sidewall  225  of the bracket  22 . The base  24   a  is securely mounted to the bracket  22  through the first locking units  227  and the second locking units  245   a  interlocked together. Each of the central tube  243  is assembled with a stator  30  and a rotor  40  around an outer periphery thereof. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.