Abstract:
A cooling fan with dynamic and static blades includes a fan and a static blade device. The fan has a fan frame with two lateral sides forming an inlet and an outlet respectively and provides dynamic blades in the fan frame. The static blades are mounted at the outlet and extend into the outlet of fan frame to reduce distance between the dynamic blades and the static blades for saving space thereof.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention is related to a cooling fan with dynamic and static blades and particularly to a fan in which the dynamic blades being arranged to separate from the static blades.  
         [0003]     2. Brief Description of the Related Art  
         [0004]     The conventional axial flow fan can be divided into single stage blade type and double stage blade type. The axial flow fan with single stage blades is a fan with dynamic blades and the axial flow fan with double stage blades is a fan with dynamic blades integrally arranged with static blades for offering fluid a propelling force by way of the dynamic and static blades rotating with the fan shaft.  
         [0005]     The preceding fan with dynamic blades provides the outward direction of air flow has to be inclining with the axis of the fan based on the principle of fluid mechanics such that the outward fluid flows divergently instead of being concentrative. In this way, the direction of air flowing is inconsistent with the cooling fins and it results in increasing resistance and lowering air flow passing through the cooling fins such that unfavorable heat dissipation effect with loud noise is obtained.  
         [0006]     The fan with dynamic blades integral with static blades improves the deficiency of the dynamic blade fan and a static blade stage is added in the fan at the rear side of the dynamic blades. The hollow frame of the fan is shared with the dynamic blades and the static blades and the static blades are able to rectify the diverging air flow from the dynamic blades to concentrate the air flow outward the fan. In this way, the direction of air flow is approximately parallel to the axial direction of the fan and consistent with the direction of the cooling fan for increasing air flow passing through the cooling fins and attenuating noise.  
         [0007]     However, the fan with dynamic blades integral with static blades still faces many problems in practice. Due to the dynamic blades being arranged integrally with the static blades, the fan is suitable for being operated in a specific environment only in order to maintain favorable work condition, high efficiency, sufficient flow rate and low noise. Further, either the dynamic blades or the static blades is damaged, both the blades have to be replaced at the same time such that high maintenance and repair costs results in a great burden to the user.  
         [0008]     Taiwanese Patent Official Gazette No. 488497 entitled FAN WITH SUPERCHARGING FLOW GUIDE DEVICE Referring and No. 523652 entitled COMPOSITE FAN WITH FAN FRAME disclose the static blades are disposed to separate from the dynamic blades for promoting air flow rate and air pressure and suitable for different environment needs.  
         [0009]     The problem of the preceding prior art is in that a large distance is created between the dynamic blades and the static blades after assembling to each other and it reduces kinetic energy of the fluid. A clearance between the assembled parts leads the fluid to overflow before reaching the static blades and it is unfavorable for increasing air pressure.  
       SUMMARY OF THE INVENTION  
       [0010]     A main object of the present invention is to a cooling fan with dynamic and static blades in which the static blades are independent from the dynamic blades and extend toward the dynamic blades to shorten distance between them and to save the space of the fan.  
         [0011]     In order to achieve the preceding object, the cooling fan with dynamic and static blade includes a fan, having a fan frame with a hollow flow passage, the flow passage having an inlet at a lateral side of the fan and an outlet at another lateral side of the fan frame; a support seat, being disposed near the outlet and joined with a plurality of dynamic blades; and at least a static blade device, being mounted to the outlet, providing a hollow frame member with a plurality of static blades, the static blades extending axially toward one of the lateral sides and into the outlet for reducing a space between the dynamic blades and the static blades. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     The detail structure, the applied principle, the function and the effectiveness of the present invention can be more fully understood with reference to the following description and accompanying drawings, in which:  
         [0013]      FIG. 1  is a disassembled perspective view of a preferred embodiment of a cooling fan with dynamic and static blades according to the present invention;  
         [0014]      FIG. 2  is a disassembled perspective view similar to  FIG. 1  illustrating the preceding embodiment being projected from another direction;  
         [0015]      FIG. 3  is a perspective view of the preceding embodiment;  
         [0016]      FIG. 4  is a sectional view of the preceding embodiment;  
         [0017]      FIG. 5  is a sectional view similar to  FIG. 4  illustrating another type of the hub thereof;  
         [0018]      FIG. 6  is a disassembled perspective view of another preferred embodiment of a cooling fan with dynamic and static blades according to the present invention;  
         [0019]      FIG. 7  is a perspective view of the preceding embodiment;  
         [0020]      FIG. 8  is a disassembled perspective view similar to  FIG. 6  illustrating the preceding embodiment being projected from another direction;  
         [0021]      FIG. 9  is an assembled perspective view illustrating the preceding embodiment being projected from another direction;  
         [0022]      FIG. 10  is a sectional view of the preceding embodiment; and  
         [0023]      FIG. 10   a  is an enlarged diagram of the part of dash circle in  FIG. 10 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]     Referring to FIGS.  1  to  4 , the first preferred embodiment of a cooling fan with dynamic and static blades according the present invention includes a fan  11  and at least a static blade device  12 . The fan  11  has a fan frame  111  with a hollow passage  112  and the passage  112  provides an inlet  113  at a side of the fan frame  111  and an outlet  114  at another side of the frame  111 . A bearing seat  115  is disposed near the outlet  114  with a dynamic blade  116  being movably attached to the bearing seat  115 .  
         [0025]     The static blade device  12  has a hollow frame member  121  with a plurality of static blades  122  being disposed inside. Each of the static blades  122  connects with the inner wall of the frame member  121  at an end thereof and extends to a common position, which is the center of the frame member  121  in the present embodiment, at the other end thereof respectively to connect with a hub  123  in a way of being perpendicular to the outer wall of the hub  123 . Alternatively, the other ends of the static blades  122  extend to the common position and join at the common position (not shown). The static blades  122  extrude outward the frame member  121  axially.  
         [0026]     Besides, the fan frame  111  has receiving parts  117  such as through holes and the frame member  121  provides joining parts  124  corresponding to the receiving parts  117 . The joining parts  124  can be locks, threaded fasteners or any other engaging means such as adhesives attached to the receiving parts  117 .  
         [0027]     The static blade device  12  is arranged to face the outlet  114  of the fan  11  and mounted to the outlet  114  with the joining parts  124  engaging with the receiving parts  117 . Meanwhile, the static blades extend into the outlet  114 , that is, extend into the flow passage  112  such that space between the dynamic blades  116  and the static blades  122  is reduced and the fluid passes through the static blades  122  without decreasing kinetic energy of the fluid after passing through the dynamic blades  116 . Further, comparing to the prior art, the fan of the present invention is more capable of allowing the fluid flowing along the axial direction of the fan in addition to increasing fluid pressure.  
         [0028]     Furthermore, the static fan device  12  is available for the fan  11  being joined to a radiator or the like, that is, the frame member  121  of the static blade device  12  provides joining parts corresponding to the radiator or the like. The joining parts can be locking pieces, threaded fasteners or any other engaging devices as well (not shown). Besides, the static blades  122  can be either integrally made with the frame member  121  and/or the hub  132  or an independent piece.  
         [0029]     In addition, the hub  123  of the static blade device  12  can be hollow except solid from standpoint of material reduction. The outer wall of the hub  123  can be provided a conical shape as shown in  FIG. 5  for the fluid being guided to concentrate toward the shaft thereof.  
         [0030]     Referring to FIGS.  6  to  10  and  FIG. 10   a , another embodiment of a cooling fan with dynamic and static blades according the present invention is illustrated. The entire structure and function almost the same as the first embodiment so that the identical parts are designated with the same numerals and no details will be described further. The difference of the present embodiment is in that the hollow fame member  121  opposite to a side of the fan frame  111  provides a protruding baffle part  125  corresponding to the flow passage  112  and the baffle part  125  is mounted to the fan  11  with the static blade device  12  such that the baffle part  125  extends into the flow passage  112  to prevent from the fluid flowing outward via the joining seam between the static blade device  12  and the fan  11 .  
         [0031]     It is appreciated that the cooling fan with dynamic and static blades according the present invention has overcome problems resided in the prior art. The static blades  122  project outward the frame member  121  and that means the frame member  121  can be thinner than that in the conventional fan. The static blades  122  extending into the inlet  113  of the fan  11  not only increases the fluid pressure but also allows the gross thickness of the fan  11  and the static blade device  12  being smaller than of the prior art. Further, the baffle part  125  is capable of preventing from fluid decrease caused by overflow and keeping flow rate of the fluid into the inlet  113 .  
         [0032]     While the invention has been described with referencing to preferred embodiments thereof, it is to be understood that modifications or variations may be easily made without departing from the spirit of this invention, which is defined by the appended claims.