Patent Publication Number: US-10330120-B2

Title: Boost fan structure

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a fan structure and in particular to a boost fan structure. 
     Description of Prior Art 
     The heat generated by the current popular electronic device is getting increasingly large. For a heat dissipating fan providing forced air flow, a performance index of the heat dissipating fan such as reduced wind pressure loss, increased wind pressure, and reduced noise is urgently required. In this regard, a counter rotating fan or a serially connected fan is commonly used in the current industry to meet the performance. However, the above-mentioned fan has a huge volume, occupying a larger operating space. 
     For a traditional counter rotating fan, the fixing of its outer frame (including the front frame and the rear frame) is performed to position and secure the fan via the penetration of long screws or the latch design, or by the screws between the front frame and the rear frame. However, the above-mentioned fixing of the outer frame is only suitable for the air channel without an arced shape. If the air channel has a slope or a curvature change (used to guide air flow to increase the wind pressure and reduce the noise) and the above-mentioned fixing method is used, the molding regarding the frame manufacturing cannot be made, which causes difficulty in manufacturing. Therefore, how to design a fan which can maintain the arc of the air channel and meet the requirements of molding and fastening during the manufacturing process is the motivation of the inventor. 
     In view of this, the inventor pays special attention to research with the application of related theory and tries to improve and overcome the above disadvantages regarding the above related art, which becomes the improvement target of the inventor. 
     SUMMARY OF THE INVENTION 
     One objective of the present invention is to provide a boost fan structure which simplifies the structure of the boost fan and decreases the whole volume and has the effects of increasing the wind pressure and reducing the noise. 
     Another objective of the present invention is to provide a boost fan structure in which the static blades of the body are exposed to a side of the frame in order to facilitate the demolding smoothly during the manufacturing process. Thus, the frame and the inner guider can form the base in an integral way to fulfill the purpose of simplifying the boost fan structure. 
     To achieve the above objectives, the present invention provides a boost fan structure which comprises a base, a motor driver set, a rotary blade set, and an outer shroud. The base has a frame and an inner guider. The inner guider has a body and a plurality of static blades. The body is disposed in the frame and has an annular curved surface and a receiving space. The static blades are formed on the annular curved surface and exposed to a side of the frame. The motor driver set is disposed in the receiving space. The rotary blade set is disposed on a side of the inner guider; the rotary blade set is driven by the motor driver set to rotate. The outer shroud has a shell having a curved inner wall. The shell covers the rotary blade set and the inner guider to be combined with the frame. 
     Compared with the prior art, the static blades of the inner guider of the boost fan structure of the present invention are formed on the annular curved surface of the body and exposed to a side of the frame, which facilitates the demolding of the inner guider during the manufacturing process. Also, the base can be formed integrally from the frame and the inner guider by injection molding. In this way, the effects of simplifying fan structure, shrinking the whole volume, and occupying less space are achieved. Besides, the static blade has arch-like surfaces and thus the cross section thicknesses of the static blade have an uneven distribution, which has a better effect of guiding air flow. In addition, the outer shroud of the present invention has a curved inner wall; the static blades are inclined disposed on the annular curved surface and spaced to each other with a vortex-like structure and have arch-like surfaces; the cross section thicknesses of each of the static blades have an uneven distribution. Therefore, a better effect of guiding air flow can be achieved. Consequently, plural air channels are formed between the outer shroud, the annular curved surface, and the static blades, which achieve the effects of reducing the wind resistance and the noise. 
    
    
     
       BRIEF DESCRIPTION OF DRAWING 
         FIG. 1  is a perspective schematic view of the boost fan structure of the present invention from one side; 
         FIG. 2  is an exploded schematic view of the boost fan structure of the present invention; 
         FIG. 3  is a perspective schematic view of the boost fan structure of the present invention from another side; and 
         FIG. 4  is an assembled cross-sectional view of the boost fan structure of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The detailed description and technical details of the present invention will be explained below with reference to accompanying drawings. However, the accompanying drawings are only for reference and explanation, but not to limit the scope of the present invention. 
     Please refer to  FIGS. 1-3 , which are a perspective schematic view of the boost fan structure of the present invention from one side, an exploded schematic view of the boost fan structure of the present invention, and a perspective schematic view of the boost fan structure of the present invention from another side, respectively. The boost fan structure  1  of the present invention comprises a base  10 , a motor driver set  20 , a rotary blade set  30 , and an outer shroud  40 . The motor driver set  20  is disposed in the base  10 . The rotary blade set  30  is driven by the motor driver set  20  to generate air vortices. The outer shroud  40  covers the rotary blade set  30  and assembled to the base  10 . In this way, the air flow generated by the rotary blade set  30  can flow through the outer shroud  40  and is guided by the base  10  to cause a change in the wind pressure. The boost fan structure  1  will be detained later. 
     The base  10  has a frame  11  and an inner guider  12 . The inner guider  12  has a body  121  and a plurality of static blades  122 . The body  121  is disposed in the frame  11  and has an annular curved surface  1211  and a receiving space  1210  formed in the annular curved surface  1211 . Also, the static blades  122  are directly formed on the annular curved surface  1211  and exposed to a side of the frame  11 . 
     In an embodiment of the present invention, the body  121  forms a supporting base  123  at the bottom of the receiving space  1210 . A side of the motor driver set  20  is pressed against the supporting base  123 . 
     The motor driver set  20  is disposed in the receiving space  1210 . The rotary blade set  30  is disposed on a side of the inner guider  12  and is driven by the motor driver set  20  to rotate. Besides, the outer shroud  40  has a shell  41  with a curved inner wall  401 ; the shell  41  covers the rotary blade set  30  and the inner guider  12  to be combined with the frame  11 . 
     In particular, as shown in  FIG. 2 , the frame  11  has a throughhole  110 . Further, a side of the body  121  is disposed through the throughhole  110  and the ends of the static blades  122  are individually extended through the throughhole  110  and formed out of the frame  11 , which completes the demolding during the manufacturing process. In this way, the frame  11  and the inner guider  12  can together form the base  10  in an integral way. 
     In the current embodiment, the static blades  122  are preferably inclined disposed on the annular curved surface  1211  and spaced to each other with a vortex-like structure. It is worth noting that each of the static blades  122  may have arch-like surfaces  1221  or the cross section thicknesses of each of the static blades  122  have an uneven distribution, which achieves a better effect of guiding air flow and reduces the wind resistance and the noise. 
     Moreover, in an embodiment of the present invention, the motor driver set  20  comprises a motor  21  and at least one bearing  22 . The rotary blade set  30  comprises a rotating shaft  31 , a cone body  32  and a plurality of blades  33  formed on the cone body  32 . Also, the shell  41  has a first opening  411 , a second opening  412  opposite to the first opening  411 , and a narrow-necked section  413  disposed between the first opening  411  and the second opening  412 . In the current embodiment, the size of the first opening  411  is smaller than that of the second opening  412  and thus a high wind pressure can be generated at the side of the first opening  411 . 
     Besides, a plurality of first fixing structures  111  is formed on a side of the frame  11  facing the shell  41 . A plurality of second fixing structures  414  is formed at the outer edge surface of the shell  41  which is near to the second opening  412  and corresponds to the first fixing structures  111 . The frame  11  and the shell  41  are fastened to each other through the first fixing structures  111  and the second fixing structures  414 . 
     In another embodiment, a first adhering structure (not shown) is formed on a side of the frame  11  facing the shell  41 . Also, a second adhering structure (not shown) is formed at the outer edge surface of the shell  41  which is near to the second opening  412  and corresponds to the first adhering structure. The first adhering structure and the second adhering structure are stuck to each other by coating an adhesive to combine the frame  11  and the shell  41 . Alternatively, the frame  11  and the shell  41  can be stuck and combined to each other directly through the adhesive. 
     Please refer to  FIG. 4 , which is an assembled cross-sectional view of the boost fan structure of the present invention. As shown in  FIG. 4 , the rotating shaft  31  of the rotary blade set  30  is combined to the motor  21  via the bearing  22 . Also, a plurality of air channels is formed between the outer shroud  40 , the annular curved surface  1211 , and the static blades  122 . Preferably, the end of the cone body  32  of the rotary blade set  30  is pressed against an end perimeter of the annular curved surface  1211  of the body  121  and thus a smooth guiding curved surface is formed. 
     In summary, the embodiments disclosed in the description are only used to explain the present invention, but not to limit the scope of the present invention. The scope of the present invention should be embraced by the accompanying claims and includes all the equivalent modifications and not be limited to the previous description.