Patent Publication Number: US-9890795-B2

Title: Cooling fan structure

Description:
FIELD OF THE INVENTION 
     The present invention relates to a cooling fan structure, and more specifically, to a cooling fan structure including a stator-blade unit set that is exchangeable according to different high impedance systems to achieve different levels of high static pressure without increasing any mold-making cost. 
     BACKGROUND OF THE INVENTION 
     As the advancement of electronic industry, various electronic elements now produce more heat than before when they operate. Therefore, natural convection is no longer sufficient for removing waste heat. In order to lower the temperature in a computer system, more than one cooling fan is generally disposed in the computer system to dissipate the heat produced by the electronic elements of the computer system. Normally, the cooling fans are mainly installed close to the heat-generating elements to lower the temperature thereof. Alternatively, the cooling fans are installed at an air inlet or an air outlet to facilitate flowing of air in the computer system. Thus, cooling fans have now become an indispensable part in the computer systems. 
     Please refer to  FIGS. 1 and 2 , which are perspective views of two conventional single-rotor blade fans  1 . As shown, the single-rotor blade fan  1  has a rotor  10  and a stator  11 . The rotor  10  includes a fan blade unit  101  having a row of fan blades spaced on a periphery thereof, whereas the stator  11  has a plurality of stator blades  111 , as shown in  FIG. 1 , or ribs  112 , as shown in  FIG. 2 , spaced on a periphery thereof. With theses arrangements, the single-rotor blade fan causes the air to flow out of the fan blade unit  101  of the rotor  10  at an angle against the stator blades  111 , so that the airflow turns to work and the fan  1  provides improved heat dissipation effect. However, the single-rotor blade fan  1 , due to its design, has relatively low pressure in the high back pressure zone, and accordingly, has relatively poor heat dissipation effect when being used with high impedance systems. 
     Please refer to  FIG. 3 , a fan module  2  is disclosed to include a housing  20 , a first and a second set of stator blades  21 ,  22 , a motor  23 , and a rotor blade unit  24 . The housing  20  has a passage  25 , two ends of which respectively form an air inlet  251  and an air outlet  252 . The first and second set of stator blades  21 ,  22  are provided on an inner wall surface of the housing  20  and located in the passage  25 . The motor  23  is arranged in the passage  25  and has a rotor  26 . The rotor blade unit  24  includes a hub  241 , a first and a second set of rotor blades  242 ,  243 . The hub  241  is fixedly mounted around the rotor  26 . The first and second sets of rotor blades  242 ,  243  are circumferentially spaced on the hub  241 . The first set of rotor blades  242  is located between the air inlet  251  and the first set of stator blades  21 , whereas the second set of rotor blades  243  is located between the first and the second set of stator blades  21 ,  22 . However, the above-mentioned structure does not disclose how the first set of rotor blades  242  is arranged between the air inlet  251  of the housing  20  and the first set of stator blades  21 , nor does it disclose how the second rotor blades  243  are arranged between the first set of stator blades  21  and the second set of stator blades  22 . Therefore, a person of ordinary skill in the art just could not implement the fan module  2  according to the above-mentioned structure. 
     SUMMARY OF THE INVENTION 
     To solve the above problems, a primary object of the present invention is to provide a cooling fan structure including a stator-blade unit set that is exchangeable according to different impedance systems to achieve different levels of static pressure. 
     Another object of the present invention is to provide a cooling fan structure that largely saves the fan&#39;s mold-making cost. 
     A further object of the present invention is to provide a practicable cooling fan structure. 
     A still further object of the present invention is to provide a cooling fan assembling method that enables a cooling fan structure to have a stator-blade unit set exchangeable according to different impedance systems to achieve different levels of static pressure. 
     A still further object of the present invention is to provide a cooling fan assembling method that enables the assembled cooling fan structure to exchange a stator-blade unit set with another one without increasing any mold-making cost. 
     A still further object of the present invention is to provide a cooling fan assembling method that includes practicable steps for assembling a cooling fan structure. 
     To achieve the above and other objects, the cooling fan structure provided according to the present invention includes a housing, a multistage fan wheel, and a stator-blade unit set. The housing is integrally formed and includes a first frame, a second frame, and a connecting spacer set connected to between the first and second frames to space them apart by a predetermined distance and define an open space therebetween. The first frame internally defines a first receiving space, whereas the second frame internally defines a second receiving space; and the first and the second receiving space are axially communicable with the open space. The multistage fan wheel is located is in the housing and includes a hub, around which a group of first rotor blades and a group of second rotor blades are formed and axially spaced, such that a bladeless zone is defined on the hub between the first and the second rotor blades. The first rotor blades are located in the first receiving space, the second rotor blades are located in the second receiving space, and the bladeless zone is located in the open space. The stator-blade unit set includes a first and a second stator-blade unit, which are radially removably assembled into the open space of the housing to circumferentially close the open space. The first and the second stator-blade unit respectively have a first and a second inner wall surface and a first and a second free end. A plurality of first air-guiding members is provided on the first inner wall surface to radially extend into the open space, whereas a plurality of second air-guiding members is provided on the second inner wall surface to radially extend into the open space; and the first and the second free end are located in the open space corresponding to the bladeless zone of the multistage fan wheel. 
     To achieve the above and other objects, the cooling fan assembling method provided according to the present invention includes the following steps: 
     Provide a housing. The housing includes a first and a second frame, and a connecting spacer set connected to between the first and the second frame to define an open space therebetween. The first frame internally defines a first receiving space, whereas the second frame internally defines a second receiving space; and the first and the second receiving space are axially communicable with the open space. 
     Fit a multistage fan wheel in the housing. The multistage fan wheel includes a hub, around which a group of first rotor blades and a group of second rotor blades are formed and axially spaced to define a bladeless zone therebetween, such that the first rotor blades are located in the first receiving space, the second rotor blades are located in the second receiving space, and the bladeless zone is located in the open space. 
     Provide a stator-blade unit set. The stator-blade unit set includes a first and a second stator-blade unit, which are radially removably assembled into the open space of the housing to circumferentially close the open space, so that the stator-blade unit set and the housing together form an integral body. 
     When assembling the cooling fan according to the method of the present invention, first fit the multistage fan wheel in the housing; and then, provide the first and the second stator-blade unit and radially assemble them into the open space of the housing to close the open space, so that the stator-blade unit set and the housing together form an integral body. In this way, the stator-blade unit set is freely exchangeable according to different high impedance systems to achieve different levels of high static pressure. Therefore, in the present invention, unlike the conventional cooling fan structures, the cost of making a whole new mold for forming another fan frame with a different stator-blade unit set can be saved. 
     Compared to Taiwan Invention Patent Pub. No. 201416560A, the present invention has provided clear steps, based on which a person of ordinary skill in the art can assemble the stator-blade unit set to the housing to form the cooling fan structure while achieving the aforesaid effects. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein 
         FIG. 1  is an assembled, partially sectioned perspective view of a first conventional cooling fan structure; 
         FIG. 2  is an assembled, partially sectioned perspective view of a second conventional cooling fan structure; 
         FIG. 3  is an assembled sectional view of a third conventional cooling fan structure; 
         FIG. 4A  is an exploded perspective view of a cooling fan structure of the present invention according to a first embodiment thereof; 
         FIG. 4B  is an assembled perspective view of the cooling fan structure of  FIG. 4A , viewed from a front left side thereof; 
         FIG. 5  is an assembled perspective view of the cooling fan structure of  FIG. 4A , viewed from a front right side thereof; 
         FIG. 6  is an assembled sectional view of the cooling fan structure of  FIG. 4A ; 
         FIG. 7  is an exploded perspective view of the cooling fan structure of the present invention according to a second embodiment thereof; 
         FIG. 8  is an exploded perspective view of the cooling fan structure of the present invention according to a third embodiment thereof; 
         FIG. 9  is an exploded perspective view of the cooling fan structure of the present invention according to a fourth embodiment thereof; 
         FIG. 10  is an assembled perspective view of the cooling fan structure of the present invention according to a fifth embodiment thereof; and 
         FIG. 11  is a flowchart showing the steps included in a cooling fan assembling method according to a preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will now be described with some preferred embodiments thereof and by referring to the accompanying drawings. For the purpose of easy to understand, elements that are the same in the preferred embodiments are denoted by the same reference numerals. 
     Please refer to  FIGS. 4A, 4B, 5, and 6 , which are exploded and assembled perspective views, and assembled sectional view, respectively, of a cooling fan structure  3  according to a first embodiment of the present invention. As shown, the cooling fan structure  3  includes a housing  30 , a multistage fan wheel  31 , and a stator-blade unit set  32 . The housing  30  is integrally formed and includes a first and a second frame  301 ,  302 , and a connecting spacer set  303  connected to between the first and second frames  301 ,  302  to space them apart by a predetermined distance and define an open space  304  therebetween. 
     The first frame  301  internally defines a first receiving space  3011 , whereas the second frame  302  internally defines a second receiving space  3021 ; and the first and the second receiving space  3011 ,  3012  are axially communicable with the open space  304 . A rear end of the second frame  302  opposite to the first frame  301  is provided with a base  33 , a central portion of which is forwardly extended to form a bearing cup  331 . The base  33  also includes a plurality of supporting portions  332  radially outward extended therefrom. In the illustrated first embodiment, the supporting portions  332  are respectively in the form of a rib. 
     The connecting spacer set  303  includes a first and a second connecting spacer  3031 ,  3032 , which are located on the housing  30  at two diagonally opposite positions. The first connecting spacer  3031  has a first and a second lateral face  3031   a ,  3031   b , whereas the second connecting spacer  3032  has a third and a fourth lateral face  3032   a ,  3032   b.    
     The multistage fan wheel  31  is located in the housing  30  and fitted around the bearing cup  331 , and includes a hub  311  having a group of first rotor blades  312  and a group of second rotor blades  313  formed therearound. The first rotor blades  312  are axially spaced from the second rotor blades  313 , such that a bladeless zone  314  is defined around the hub  311  between the first and the second rotor blades  312 ,  313 . The first rotor blades  312  are located in the first receiving space  3011 ; the second rotor blades  313  are located in the second receiving space  3021 ; and the bladeless zone  314  is located in the open space  304 . 
     The stator-blade unit set  32  includes a first and a second stator-blade unit  321 ,  325 , which are radially removably assembled into the open space  304  of the housing  30  to circumferentially close the open space  304 . The first and the second stator-blade unit  321 ,  325  respectively have a first and a second inner wall surface  322 ,  326 , and a first and a second free end  324 ,  328 . A plurality of first air-guiding members  323  is provided on the first inner wall surface  322  to radially extend into the open space  304 , whereas a plurality of second air-guiding members  327  is provided on the second inner wall surface  326  to radially extend into the open space  304 . The first and the second free end  324 ,  328  are located in the open space  304  corresponding to the bladeless zone  314  of the multistage fan wheel  31 . 
     Two ends of the first stator-blade unit  321  respectively form a first and a second end face  321   a ,  321   b , whereas two ends of the second stator-blade unit  325  respectively form a third and a fourth end face  325   a ,  325   b . The first and the second end face  321   a ,  321   b  of the first stator-blade unit  321  are respectively in contact with the first and the third lateral face  3031   a ,  3032   a  of the connecting spacer set  303 , whereas the third and the fourth end face  325   a ,  325   b  are respectively in contact with the second and the fourth lateral face  3031   b ,  3032   b  of the connecting spacer set  303 . 
     Please refer to  FIGS. 4A, 4B, 5, and 6  again. In the illustrated first embodiment, the first and the second rotor blades  312 ,  313  are oriented in the same direction, the number of the first and of the second rotor blades  312 ,  313  are the same, and the first and the second air-guiding member  323 ,  327  are respectively in the form of a fan blade. With these arrangements, the stator-blade unit set  32  is freely exchangeable according to different impedance systems to achieve different static pressure effects. Therefore, unlike the conventional cooling fan structure, in the present invention, the cost of making a whole new mold for forming a fan frame with a different stator-blade unit set can be saved. 
     Please refer to  FIG. 7 , which is an exploded perspective view of the cooling fan structure according to a second embodiment of the present invention. The cooling fan structure  3  in the second embodiment is generally structurally similar to the first embodiment except that, in this second embodiment, the first and the second rotor blades  312 ,  313  are oriented in two different directions. 
     Please refer to  FIG. 8 , which is an exploded perspective view of the cooling fan structure according to a third embodiment of the present invention. The cooling fan structure  3  in the third embodiment is generally structurally similar to the first embodiment except that, in this third embodiment, the first and the second rotor blades  312 ,  313  are different in number, such that the first and the second rotor blades  312 ,  313  are not correspondingly spaced on the hub  311 . 
     Please refer to  FIG. 9 , which is an exploded perspective view of the cooling fan structure according to a fourth embodiment of the present invention. The cooling fan structure  3  in the fourth embodiment is generally structurally similar to the first embodiment except that, in this fourth embodiment, the first and the second air-guiding member  323 ,  327  are respectively in the form of a rib. 
     Please refer to  FIG. 10 , which is an assembled perspective view of the cooling fan structure according to a fifth embodiment of the present invention. The cooling fan structure  3  in the fifth embodiment is generally structurally similar to the first embodiment except that, in this fifth embodiment, the supporting portions  332  outwardly extended from the base  33  are respectively in the form of a fan blade. 
     Please refer to  FIG. 11 , which is a flowchart showing the steps S 1 , S 2  and S 3  included in a cooling fan assembling method according to a preferred embodiment of the present invention. 
     In the step S 1 , a housing is provided. The housing includes a first and a second frame, and a connecting spacer set connected to between the first and the second frame to define an open space therebetween; the first frame internally defines a first receiving space, whereas the second frame internally defines a second receiving space; and the first and the second receiving space are axially communicable with the open space. 
     More specifically, in the step S 1 , a housing  30  is provided first. The housing  30  includes a first and a second frame  301 ,  302 , and a connecting spacer set  303  connected to between the first and the second frame  301 ,  302  to define an open space  304  therebetween. The first and the second frame  301 ,  302  respectively internally define a first and a second receiving space  3011 ,  3021 , which are axially communicable with the open space  304 . 
     In the step S 2 , a multistage fan wheel is fitted in the housing. The multistage fan wheel includes a hub, around which a group of first rotor blades and a group of second rotor blades are formed and axially spaced to define a bladeless zone therebetween, such that the first rotor blades are located in the first receiving space, the second rotor blades are located in the second receiving space, and the bladeless zone is located in the open space. 
     More specifically, in the step S 2 , a multistage fan wheel  31  is fitted in the housing  30 . The multistage fan wheel  31  includes a hub  311 , around which a group of first and a group of second rotor blades  312 ,  313  are formed and axially spaced to define a bladeless zone  314  therebetween, such that the first rotor blades  312  are located in the first receiving space  3011 , the second rotor blades  313  are located in the second receiving space  3021 , and the bladeless zone  314  is located in the open space  304 . 
     In the step S 3 , a stator-blade unit set is provided. The stator-blade unit set includes a first and a second stator-blade unit, which are radially removably assembled into the open space of the housing to circumferentially close the open space, so that the stator-blade unit set and the housing together form an integral body. 
     More specifically, in the step S 3 , a stator-blade unit set  32  is provided. The stator-blade unit set  32  includes a first and a second stator-blade unit  321 ,  325 , which are radially removably assembled into the open space  304  of the housing  30  to circumferentially close the open space  304 , so that the stator-blade unit set  32  and the housing  30  together form an integral body. 
     According to the above embodiment, the stator-blade unit set  32  is removably connected to the housing  30  by press-fitting. In practical implementation, however, the stator-blade unit set  32  can be removably connected to the housing  30  in other different ways, including but not limited to riveting, snap-fitting, bonding, screwing, and fixing with external elements. 
     When assembling the cooling fan structure  3  according to the method of the present invention, first fit the multistage fan wheel  31  in the housing  30 ; and then, provide the first and the second stator-blade unit  321 ,  325  and radially removably assemble them into the open space  304  of the housing  30  to circumferentially close the open space  304 , so that the stator-blade unit set  32  and the housing  30  together form the cooling fan structure  3 . In this way, the stator-blade unit set  32  is freely exchangeable according to different high impedance systems to achieve different levels of high static pressure. Therefore, unlike the conventional cooling fan structure, in the present invention, the cost of making a whole new mold for forming another fan frame with a different stator-blade unit set can be saved. 
     Compared to Taiwan Patent Pub. No. 201416560A, the present invention has provided clear steps, based on which a person of ordinary skill in the art can assemble the stator-blade unit set  32  to the housing  30  to form the cooling fan structure  3  while achieving the aforesaid effects. 
     The present invention has been described with some preferred embodiments thereof and it is understood that many changes and modifications in the described embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.