Abstract:
A heat dissipating fan has a round disk. The bottom of the round disk has a receiving portion concave upwards for receiving a motor  14.  A periphery of the round disk has a plurality of cambered extending blades which are arranged regularly. The plurality of blades extends along a cambered path. Each blade has a convex surface and a concave surface. Each convex surface has a protruding flow guide opposite to the concave surface of the blade; and at a connection of the flow guide and the blade has at least one cambered surface.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a heat dissipating fan, and especially to a heat dissipating fan having cambered blades each having a convex surface.  
         BACKGROUND OF THE INVENTION  
         [0002]    In order to match the compact size of current notebook computer, air flow of heat dissipating fan is changed from the longitudinal output to a transversal output (such as a blower). The prior art heat dissipating fan is illustrated in FIGS. 8 and 9. The periphery of the rotary disk  81  is extended with blades  82  with cambered surfaces. Each blade  82  has a tilt wind cutting angle α. Furthermore, wind is guided along the cambered surface of the blade and wind pressure is boosted so that air is boosted to be pushed out. However, this kind of fan has only the function of absorbing air at the upper side and outputting air from the lateral side. Therefore, it only dissipates heat at a single direction. It is not suitable for the device which needs to dissipate heat at the upper and lower sides. Furthermore, the blade  82  only cuts a little air in a cutting angle α. Although the noise generated is smaller, the absorbing air is small. Next, this heat dissipating fan is made by injecting plastics for reducing cost. However, the molds used in injection must match with the cambered surface of the blade  82  having a complex shape. Therefore, the mold can not be formed by an upper and a lower mold. Thus, a plurality of mold cores (not shown) must be designed to be inserted into the blades  82 . However, the mold has a complex structure and a high cost. This is not suitable for the parts necessary to reduce cost.  
           [0003]    Another prior art design is illustrated in FIGS. 10 and 11, in that a plurality of straight blades  92  are protruded slightly from the periphery of the rotary disk  91  so that air is absorbed at the upper and lower sides. As a result, heat is dissipated from the upper and lower sides. In manufacturing, the complex structure of the mold in the cutting type heat dissipating fan is improved. The mold can be formed by an upper and lower molds. However, as this kind of blades  92  rotates, instead of cutting air, they beat air to induce a large amount of air. Furthermore, as the blades  92  beat air, the air at the upper and lower edges of the blades will be extruded out so as to be formed with a resisting force. This resisting force will affect the load of the motor (not shown), and thus, the lifetime of the motor is reduced.  
         SUMMARY OF THE INVENTION  
         [0004]    Accordingly, the primary object of the present invention is to provide a heat dissipating fan, wherein by the cambered surfaces of the blades, air from the upper and lower wind inlets can be driven so as to have a preferred heat dissipating effect.  
           [0005]    To achieve above objects, the present invention provides a heat dissipating fan, the cambered surface of the blade will cut air and increase the flow guiding. Therefore, noise is reduced and moreover, the air will not be turbulent to the upper and lower sides. The resistance to the absorbed air is reduced and further air is increased. Thus, the load of the motor is reduced, thereby causing the lifetime of the motor to be prolonged.  
           [0006]    The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a perspective view of the first embodiment in the present invention.  
         [0008]    [0008]FIG. 2 is a top view of the first embodiment in the present invention, wherein the arrow indicates the direction of air flow.  
         [0009]    [0009]FIG. 3 is a lateral view of the first embodiment of the present invention, wherein the arrow shows the direction of air flow.  
         [0010]    [0010]FIG. 4 is a schematic view showing the application of the first embodiment of the present invention.  
         [0011]    [0011]FIG. 5 is a cross sectional view along the line V-V of FIG. 4.  
         [0012]    [0012]FIG. 6 is a lateral view of the second embodiment of the present invention.  
         [0013]    [0013]FIG. 7 is a lateral view of the third embodiment of the present invention.  
         [0014]    [0014]FIG. 8 is a perspective view of a prior art heat dissipating fan.  
         [0015]    [0015]FIG. 9 is a lateral view of FIG. 8.  
         [0016]    [0016]FIG. 10 is a perspective view of another prior art heat dissipating fan.  
         [0017]    [0017]FIG. 11 is a lateral view of FIG. 10. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    Referring to FIGS.  1  to  5 , the heat dissipating fan of the present invention is illustrated. The heat dissipating fan of the present invention is installed to a casing  10 . The top of the bottom of the casing  10  has respective wind inlets  13 . The lateral side of the casing  10  has a wind outlet  12 . The inner side of the wind inlet at the bottom of the casing  10  is installed with a retaining disk  13 . The center of the retaining disk  13  is installed with a motor  14 . The motor  14  has a rotary shaft  141  extending upwards. The upper end of the rotary shaft  141  is combined to a center of a round disk. The bottom of the round disk  20  has a receiving portion  22  concave upwards. The motor  14  is received in the receiving portion  22 . The periphery of the round disk  20  has a plurality of cambered extending blades  21 . The plurality of blades  21  are extended counterclockwise (viewing downwards). An angle of 15 to 75 degrees is formed between each blade and the normal line L at the connection of the round disk. Each blade is installed with a convex surface  211  and a concave surface  212 . The middle portion of one side of the convex surface  211  has a flow guide  213  projected at an opposite position of the concave surface  212  of the blade  21 . At the connecting portion of the flow guide  213  and the blades  21  has a cambered surface  214 .  
         [0019]    It should be appreciated that as the present invention is driven by the motor  14  so as to rotate counterclockwise (viewing downwards), the periphery of the casing  10  is formed with a turbulent space H. Each blade  21  at the periphery of the round disk  20  will cut the wind at the front end of the rotating path. As the air is cut, it is pushed forwards by the convex surface  211  of the blade  21 . Then, the air is driven away, while air at other portion flows into the wind inlet  11 . Another, the air cut away flows to the opening end of the blade  21  along the cambered surface  214  of the convex surface  211  (as FIGS. 2 and 3). After the air is left from the blade  21 , it become as a boosting pressure in the turbulent space H of the casing  10 . Then the boosted air is vented out from the wind outlet  12 .  
         [0020]    In one application of the present invention, it is installed within a notebook computer (not shown), since as the present invention is driven by a motor  14 , the flow guide  213  of the blade  12  will separate a space into two cambered surfaces  214  so that air flows from the upper and lower wind inlets  11  are driven by the blade  21 . The upper and lower side of the blade  21  can cut the air. Therefore, the upper and lower wind inlets  11  of the casing  10  have the function of absorbing heat. Therefore, in the present invention, air is inputted from the upper and lower sides so as to have a preferred heat dissipating effect. Furthermore, as each blade  21  cuts air, air flows to the inner side thereof and the outer edge (as illustrated in FIG. 3) of the blade  21 . The cut air do not flow to the upper and lower sides and therefore, it makes no resistance force to the absorbed air from the wind inlet  11 . When the resistance of the inlet air is decreased, the load of the motor  14  is also reduced. Thus, the lifetime of the motor  14  will increase. The blade  21  of the present invention cuts air by the cambered surface  214  thereof to increase the guide of air. It is not by beating, and thus noise is reduced. Next, since the blade  21  of the present invention has no complex curved surface, it can be made by an upper and a lower mold so that the cost is low.  
         [0021]    In summary, the blades  21  of the heat dissipating fan according to the present invention may drive the air from the upper and lower wind inlets  11  so as to have a preferred heat dissipating effect. The cambered surface  214  of the blade  21  will cut air and increase the flow guiding. Therefore, noise is reduced and moreover, the air will not be turbulent to the upper and lower sides. The resistance to the absorbed air is reduced and further air is increased. Thus, the load of the motor  14  is reduced, thereby causing the lifetime of the motor  14  to be prolonged. Furthermore, by the design of the flow guide  213  of the blade  21 , the mold can be designed easily and therefore, manufacturing cost is increased.  
         [0022]    Of course, many embodiments may embody the present invention. One of the embodiment is illustrated in FIG. 6, which is the second embodiment of the present invention. In the present invention, the flow guide  32  of the blade  31  is installed at the bottom edge. Only an upper cambered surface  34  is formed between the flow guide  32  and the convex surface  33 . That is, the blade  31  has a preferred effect to drive air from the upper wind inlet (not shown) so that the present invention has the same function as the prior art.  
         [0023]    Referring to FIG. 7, a third embodiment of the present invention is illustrated. In this embodiment, a flow guide  41  is installed to be near the top edge of the blade  42  so that the each blade  42  has different cambered surface  43 , thereby causing the flow guides  41  of the blade  42  to have different widths in the upper and lower sides to match the areas of the wind inlets (not shown).  
         [0024]    The present invention are thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.