Abstract:
A fan frame device includes a plastic frame member and a metal reinforcing member. The inner side of the frame defines a flow path for receiving a fan wheel. The metal reinforcing member is joined to the frame member integrally. The inner side of the frame is arranged to have a largest diameter so that the flow passage provides more space for accommodating a larger sized fan wheel. Hence, strength of the frame is reinforced, vibration and noise are reduced during a fan wheel running and integral effect of heat dissipation is enhanced largely.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention is related to a fan frame device and particularly to a fan frame, which provides a plastic frame member and a metal reinforcing member.  
         [0003]     2. Brief Description of the Related Art  
         [0004]     The fan is an essential part of air-cooling radiator device and plays an important role for heat dissipation effect. The fan is the only movable part in the radiator device. Meanwhile, noise of the radiator device is influenced directly by the fan. The fan induces air to move through the cooling fins with a specific speed and a specific way for heat exchange being performed between the air and the cooling fins such that accumulated heat at the cooling fins can be carried away to achieve heat removal with forced convection.  
         [0005]     Air flow and air pressure are factors deciding how powerful a fan is. The air flow refers a product of an area of the air passing through and a velocity of the air passing through the area. When the velocity is constant, larger outer diameter of the fan wheel leads to larger flowing area and more air flow can be induced. More air flow allows the cool air absorbs more heat so that the moving air can carry with more heat and effect of heat dissipation is enhanced. The air pressure refers addition of a static pressure and a dynamic pressure of the air so that greater air pressure enhances air-delivering capability of the fan.  
         [0006]     In order to promote the gross effect of heat dissipation, the big sized fan has been employed to enhance heat dissipation efficiency. However, due to space limitation, not all the cooling systems are able to use the big sizes fan even if the smaller sized fan is unable to reach the expect effect of heat dissipation.  
         [0007]     The inventor has found that if the inner side of the fan frame, i.e., the flow path of air, is increased radially under a condition of the size of the fan frame being unchanged, that is, the material between the outer side and the inner side becomes thinner. In other words, the air inlet and the air outlet areas can be increased and a bigger size fan wheel can be mounted to the inner side for generating more air flow.  
         [0008]     Further, the inventor has found that most part of a fan frame is made of plastics and a little part of the fan frame is made of metal. The fan frame with plastic material is light but the strength thereof becomes weak in case of the fan frame being made thinner. The plastic fan frame is easy to become deformed in case of being subjected to a fore and to become soft in case of being subjected to a high ambient temperature for a long period of time. As a result, normal operation of the fan is affected substantially.  
         [0009]     The metal fan frame provides enough strength but it is heavy and easy to produce louder noise while the air passing the fan frame to hit the inner wall of the fan frame. In addition, the metal fan frame is more costly than the plastic fan frame and manufacturing process of the metal fan frame is more complicated than the plastic fan frame.  
       SUMMARY OF THE INVENTION  
       [0010]     In order to solve the preceding problems, an object of the present invention is to provide a fan frame device with which the inner side of the fan frame member expands toward the outer side thereof to the most for the flow path thereof being able to accommodate a fan wheel with a bigger diameter and promoting heat dissipation effect.  
         [0011]     Another object of the present invention is to provide a fan frame structure in which the fan frame is composed of a plastic frame member and a metal reinforcing member for strengthening the fan frame and lessening noise and vibration.  
         [0012]     Accordingly, the fan frame device according to the present invention includes a plastic frame member and a metal reinforcing member. The frame member has an outer side and an inner side. The inner side of the frame member defines a flow path for accommodating a fan wheel. The metal reinforcing member is joined to the frame integrally. The inner side of the frame is arranged to have a largest diameter so that the flow path provides more space for accommodating a larger size fan wheel. Hence, strength of the frame is reinforced, vibration and noise are reduced during a fan wheel running and integral effect of heat dissipation is enhanced largely. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     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:  
         [0014]      FIG. 1  is a perspective view of the first embodiment of a fan frame device according to the present invention;  
         [0015]      FIG. 2  is a fragmentary sectional view along line A-A of  FIG. 1 ;  
         [0016]      FIG. 3  is a perspective view illustrating a metal reinforcing member being disposed between the inner side and the outer side of the first embodiment of a fan frame according to the present invention;  
         [0017]      FIG. 4  is a perspective view of the metal reinforcing member being disposed at the outer side of the first embodiment of a fan frame device according to the present invention;  
         [0018]      FIG. 5  is a plan view of the first embodiment of a fan frame device according to the present invention illustrating the first type discontinuously shaped metal reinforcing member;  
         [0019]      FIG. 5A  is an enlarged view of the dashed circle area of  FIG. 5 ;  
         [0020]      FIG. 6  is another plan view of the first embodiment of a fan frame device according to the present invention illustrating the second type discontinuously shaped metal reinforcing member;  
         [0021]      FIG. 7  is a further plan view of the first embodiment of a fan frame device according to the present invention illustrating the third type discontinuously shaped metal reinforcing member;  
         [0022]      FIG. 7A  is an enlarged view of the dashed circle area of  FIG. 5 ;  
         [0023]      FIG. 8  is a perspective view illustrating the fourth type discontinuously shaped metal reinforcing member of the first embodiment of a fan frame device according to the present invention;  
         [0024]      FIG. 9  is a perspective view illustrating two fan wheels being mounted in series to the first embodiment of a fan frame device according to the present invention;  
         [0025]      FIG. 10  is a perspective view illustrating the first type arrangement of the second embodiment of a fan frame device according to the present invention;  
         [0026]      FIG. 11  is a perspective view illustrating the second type arrangement of the second embodiment of a fan frame device according to the present invention;  
         [0027]      FIG. 12  is a perspective view illustrating the third type arrangement of the second embodiment of a fan frame device according to the present invention;  
         [0028]      FIG. 13  is a perspective view illustrating the metal reinforcing member in the first type arrangement of the second embodiment of a fan frame device according to the present invention shown in  FIG. 10  providing ventilating apertures;  
         [0029]      FIG. 14  is a perspective view illustrating the second type arrangement of the second embodiment of a fan frame device according to the present invention shown in  FIG. 11  providing air apertures;  
         [0030]      FIG. 15  is a perspective view illustrating the third type arrangement of the second embodiment of a fan frame device according to the present invention shown in  FIG. 12  providing air apertures;  
         [0031]      FIG. 16  is a diagram illustrating characteristics of the fan with fan frame of the invention and the conventional fan frame in a way of air pressure curves with respect to flow rate; and  
         [0032]      FIG. 17  is a diagram illustrating characteristics of the fan with fan frame of the invention and the conventional fan frame in a way of noise curves with respect to fan speed. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0033]     Referring to  FIGS. 1 and 2 , the first embodiment of a fan frame device according to the present invention provides a frame member  11 , which has an inner frame side  111  and an outer frame side  112 . The inner frame side  111  defines a flow path  113  for receiving a fan wheel  12 . An inlet  114  and an outlet  115  of the flow path  113  are formed at the front side and the rear side of the frame member  11  respectively. The outer frame side  112  defines the size of the frame member  11 . The frame member  11  is made of plastics and integrally joined to a metal reinforcing member  13  as a single piece by means of, for instance, the plastic frame member  11  being joined to the metal reinforcing member  13  preset in a molding tool during injection molding being performed.  
         [0034]     The plastic frame member  11  provides a gross volume greater than the metal reinforcing member  13 . Each of the four sides of the frame member  11  provides the shortest distance between the frame inner side  111  and the frame outer side  112 , that is, spots a, b, c, d indicated by an arrow respectively are the shortest distances between the frame inner side  111  and the frame outer side  112  such that the inner side  111  expands radially to the most. That is, dimension of the outer side  112  is the same as the conventional fan frame but the inner side  11  provides a diameter greater than that of the conventional fan frame such that the spots a, b, c, and d are thinnest areas of the frame member  11 .  
         [0035]     The preceding metal reinforcing member  13  can be disposed next to the frame inner side  111  to face the fan wheel  12  as shown in  FIG. 1  after the plastic frame  11  being joined to the metal reinforcing member  13 . In other words, the inner side  111  is the metal reinforcing member  13 .  
         [0036]     Referring to  FIG. 3 , the metal reinforcing member  13  can be disposed between the frame inner side  111  and the frame outer side  112  and exposes at the four thinnest areas a, b, c and d. That is, the thinnest areas a, b, c and d are formed by the metal reinforcing member  13 . Referring to  FIG. 4 , the metal reinforcing member  13  can be disposed at the frame outer side  112 , that is, the metal reinforcing member  13  constitutes the frame outer side  112 .  
         [0037]     The preceding metal reinforcing members  13  are belonged to annular type metal reinforced members  13 . It is noted that discrete type metal reinforcing member  13  can be employed except the preceding annular type.  
         [0038]     Referring to  FIGS. 5 and 5 A, the metal reinforcing member  13  is belonged to discrete type. The metal reinforcing member  13  is composed of a pair of metal reinforcing member parts and the two metal reinforced member parts are fixedly joined oppositely at the thinnest areas (a, b) and (c, d) respectively without exposure. Next, referring to  FIG. 6 , the metal reinforcing member parts are fixedly joined oppositely to the frame member  11  and expose at the thinnest areas (a, b) and (c, d) respectively. That is, the metal reinforcing member  13  constitute the thinnest areas a, b, c and d. Further, referring to  FIGS. 7 and 7 A, the metal reinforcing member  13  is composed of two pair of metal reinforcing member parts and the four metal reinforced member parts are fixedly joined at the four thinnest areas (a, b, c and d respectively without exposure. Further, referring to  FIG. 8 , the metal reinforcing member parts are fixedly joined to frame member  11  and expose at the thinnest areas (a, b) and (c, d) respectively. That is, the metal reinforcing member  13  constitute the thinnest areas a, b, c and d.  
         [0039]     Referring to  FIG. 9 , two fan wheels  12  are capable of being arranged in series in the frame  11  instead of a single fan wheel  12  in the first embodiment. Of course, it is feasible that more than two fan wheels  12  in series are arranged in the frame member  11  in case of enough space being available in the frame  11 .  
         [0040]     Referring to FIGS.  10  to  15 , the second embodiment of a fan frame device according to the present invention is illustrated. The entire structure and functions of the second embodiment is almost the same as the preceding embodiment. The difference of the second embodiment from the preceding embodiment is in that the metal reinforcing member  13  provides a shape the same as the frame member  11  and is disposed next to the inlet  114  as shown in  FIG. 10 , next to the outlet  115  as shown in  FIG. 11  or between the inlet  114  and the outlet  115  as shown in  FIG. 13 . It is noted that the frame member  11  is divided into two portions and the metal reinforcing member  13  is sandwiched by the two portions of the frame member  11 .  
         [0041]     Referring to FIGS.  13  to  15 , the metal reinforcing member  13  in  FIG. 13  is almost the same as that shown in  FIG. 10 , the metal reinforcing member  13  in  FIG. 14  is almost the same as that shown in  FIG. 11  and the metal reinforcing member  13  shown in  FIG. 15  is almost the same as that shown in  FIG. 12 . The difference of the metal reinforcing member  13  shown in FIGS.  11  to  13  respectively from that shown in FIGS.  10  to  12  is in that a plurality of apertures  131  are provided at the lateral sides of the metal reinforcing member  13  for admitting fluid and increasing air flow induced by the fan.  
         [0042]     Furthermore, the metal reinforcing member  13  in the preceding embodiments can be made of high strengthen compound material such as polymeric fiber and/or carbon fiber and/or plastic fiber and/or carbon-plastic fiber instead of metal.  
         [0043]     Referring to  FIG. 16 , curve of the air pressure in relation to flow rate is for the fan F 1 , which provides the fan frame of the present invention, and curve of the air pressure in relation to flow rate is for the fan F 2 , which provides the conventional fan frame. Due to the diameter of the inner side in the fan frame of the present invention is greater than that of the conventional fan frame and a bigger sized fan wheel is able to be mounted to the fan frame of the present invention, the air pressure induced by the fan F 1  is greater than that induced by the fan with the conventional fan frame under a condition of the same flow rate and, by the same token, the air flow of the fan F 1  is greater than that of the fan with the conventional fan frame under a condition of the same air pressure. Hence, entire fan characteristics of the fan F 1  are much higher than those of the fan F 2 .  
         [0044]     Referring to  FIG. 17 , curve of noise in relation to fan speed for the fan F 1  provides the fan frame of the present invention and curve of noise in relation to fan speed for the fan F 2  provides the conventional fan frame. Taking a range of fan speed between 6,000 rpm and 16,000 rpm for explanation, it can be seen the noise of the fan F 1  is between 23 dBA and 45 dBA but the noise of the fan F 2  is between 26 dBA and 49 dBA. That is, the fan F 1  generates lower noise than the fan F 2  because of the fan frame of the present invention is composed of a plastic frame and a metal member.  
         [0045]     As the foregoing, it is appreciated that comparing to the prior art, the fan frame structure of the application has the following advantages:  
         [0046]     1. The plastic frame member  11  is joined to the metal reinforcing member  13 , which also can be made of compound material, intimately for lessening noise generated from the fluid impacting the frame member  11  and diminishing consonant vibrations during the fan wheel  12  running in addition to intensifying strength thereof.  
         [0047]     2. The frame member  11  is integrally joined to the metal reinforcing member  13  or the compound member provides higher strength such that the inner side  111  of the frame member  11  can be arranged to expand radially and outwardly toward the outer sides  112  to the most to obtain the bigger diameter of the inner side  111  than the prior art. In this way, the inlet and outlet of the frame member  11  becomes larger and more flow rate and higher air pressure can be obtained. Further, the flow passage  113  surrounded by the inner side  111  becomes more space for accommodating larger fan wheel  12  and increasing the flow rate.  
         [0048]     3. The thinnest spots a, b, c and d of the frame member  11  can be obtained once the inner side of the frame member  11  expands radially toward the outer sides  112  to the most under support of the metal frame  15 . Hence, it is capable of overcoming the deficiency of the conventional plastic fan frame providing insufficient strength and being easily deformed after being subjected to heat for a long period of time.  
         [0049]     4. Due to the volume of the plastic frame member  11  is more than that of the metal reinforcing member  13 , the entire fan frame of the present invention is lighter than the conventional metal fan frame so that not only the cost of the fan frame can be lowered but also it is capable of overcoming the problems of noise and vibrations, which the conventional metal fan frame is unable to breakthrough.  
         [0050]     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.