Patent Publication Number: US-2013248144-A1

Title: Fan module

Description:
FIELD OF THE INVENTION 
     The present invention relates to a fan module, and more particularly to a fan module that allows at least one cross-flow fan to create largely increased air flow volume, has reduced overall volume, provides upgraded heat dissipation performance, and effectively overcomes the problems of vibration and noise caused by excessively long blades as found in the conventional fan module. 
     BACKGROUND OF THE INVENTION 
     Due to the constant progress in the electronic technological fields, the density of transistors on various kinds of chips, such as the central processing unit and other executing elements, also increases to enable faster data processing speed. However, more power is consumed and more heat is produced by these chips during high-speed operation thereof. For the central processing unit to work stably, it has become an important issue as how to develop a high-efficient heat dissipation means for dissipating the produced heat. 
     To maintain high-efficient heat dissipating function, it is inevitable to keep increasing the volume and accordingly the weight of the heat dissipation means. However, in the design of currently very popular notebook computers, tablet computers, smart mobile phones, smart hand-held electronic devices and the like, the limited internal space thereof is always a bottleneck to the heat dissipation means design. 
       FIG. 1  shows a conventional fan module  1 , which includes a centrifugal fan  10 , a heat pipe  11 , and a heat radiation unit  12 . The conventional fan module  1  uses the centrifugal fan  10  to produce flowing air, which carries away heat absorbed by the heat radiation unit  12  to thereby achieve the purpose of lowering temperature. The performance of the fan module  1  is determined by the air pressure and air flow volume produced by the centrifugal fan  10  as well as the area of the heat radiation unit  12  available for heat exchange. When the heat radiation unit  12  has larger heat exchange area by having longer radiation fins, better heat removal effect can be achieved. However, the long radiating fins tend to increase the overall volume of the fan module, and a big fan module just fails to meet the demands for compact, slim and light weight notebook computers and the like. 
     To meet the demands for compact, slim, and light weight electronic devices, all related elements of the electronic devices are minimized in dimensions. That is, the centrifugal fan in the fan module must also be miniaturized. However, the air flow volume that can be produced by the volume-reduced centrifugal fan is also reduced to largely adversely affect the heat removal effect thereof. Further, the miniaturized centrifugal fan usually has thin but large-area fan blades, which tend to produce more vibration and noise when the centrifugal fan operates. 
     As a result, it has become a target of many related manufacturers to effectively upgrade the performance of the heat radiation unit without increasing the volume thereof. 
     In brief, the conventional fan module has the following disadvantages: (1) having a relatively big volume; (2) providing low heat dissipation ability; and (3) tending to produce vibration and noise during operation thereof. 
     It is therefore tried by the inventor to develop an improved fan module to overcome the drawbacks in the conventional fan module. 
     SUMMARY OF THE INVENTION 
     A primary object of the present invention is to effectively solve the above-mentioned problems by providing a fan module having at least one cross-flow fan, so that the fan module can have reduced volume while the cross-flow fan can create largely increased air flow volume. 
     Another object of the present invention is to provide a fan module that provides upgraded heat dissipation performance and effectively overcomes the problems of vibration and noise caused by swaying of excessively long blades. 
     To achieve the above and other objects, the fan module according to the present invention includes a heat transfer unit, a heat radiation unit, and at least one cross-flow fan. The heat transfer unit has an end attached to a heat source. The heat radiation unit is connected to another opposite end of the heat transfer unit and has an air-in side and an air-out side communicable with the air-in side. The cross-flow fan is located against the heat radiation unit, and includes a frame and a centrifugal fan blade assembly. The frame has an air outlet facing toward the air-in side of the heat radiation unit, a plurality of air inlets, and a plurality of frame sections. The air inlets are respectively arranged between two adjacent frame sections and communicate with the air outlet. The frame sections are respectively configured as a receiving recess, and the receiving recesses are communicable with one another to together define a receiving space. The receiving space communicates with the air outlet and the air inlets, and is used to receive the centrifugal fan blade assembly therein. 
     The fan module with the above design can be used in a limited space, and the cross-flow fan thereof not only creates largely increased air flow volume, but also enables effectively reduced volume of the fan module. Further, the problems of vibration and noise caused by the swaying long blades as found in the conventional fan module can also be effectively improved. 
    
    
     
       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 perspective view of a conventional fan module; 
         FIG. 2A  is an exploded perspective view of a fan module according to a first embodiment of the present invention; 
         FIG. 2B  is an assembled view of  FIG. 2A ; 
         FIG. 3A  is an exploded perspective view of a fan module according to a second embodiment of the present invention; 
         FIG. 3B  is an assembled view of  FIG. 3A ; and 
         FIG. 4  is an exploded perspective view of a fan module according to a third embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will now be described with some preferred embodiments thereof and with reference 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. 2A and 2B , which are exploded and assembled perspective views, respectively, of a fan module  2  according to a first embodiment of the present invention. As shown, the fan module  2  in the first embodiment includes a heat transfer unit  20 , a heat radiation unit  21 , and at least one cross-flow fan  22 . 
     The heat transfer unit  20  includes a heat-absorbing section  201  and a heat-dissipating section  202 . The heat-absorbing section  201  is attached to a heat source  24 , such as a central processing unit, south bridge and north bridge chipsets, a graphics chip, or an executing unit. The heat-absorbing section  201  absorbs heat produced by the heat source  24  and the absorbed heat is transferred to the heat-dissipating section  202 . The heat transfer unit  20  can be a heat pipe, a heat spreader, or any element capable of transferring heat. In the illustrated first embodiment, the heat transfer unit  20  is configured as a heat pipe but is not necessarily limited thereto. 
     The heat radiation unit  21  is connected to the heat-dissipating section  202  of the heat transfer unit  20 , and has an air-in side  213  and an air-out side  214  communicating with the air-in side  213 . The heat radiation unit  21  can be a radiating fin assembly, a heat sink, or any element capable of radiating heat. In the illustrated first embodiment, the heat radiation unit  21  is configured as a radiating fin assembly but is not necessarily limited thereto. In the first embodiment, the heat radiation unit  21  includes a plurality of radiating fins  211 , and any two adjacent radiating fins  211  together define an air-guiding passage  212  between them. All the air-guiding passages  212  communicate with both of the air-in side  213  and the air-out side  214 . 
     The cross-flow fan  22  is located against the heat radiation unit  21 , and includes a frame  221  and a centrifugal fan blade assembly  222 . The frame  221  has an air outlet  2212  facing toward the air-in side  213  of the heat radiation unit  21 , a plurality of air inlets  2211 , and a plurality of frame sections  2213 . The air inlets  2211  are respectively arranged between two adjacent frame sections  2213  and communicate with the air outlet  2212 . The frame sections  2213  are respectively configured as a receiving recess  2213   a,  and the receiving recesses  2213   a  are communicable with one another to together define a receiving space  2214 . The receiving space  2214  communicates with the air outlet  2212  and the air inlets  2211 , and is used to receive the centrifugal fan blade assembly  222  therein. 
     The centrifugal fan blade assembly  222  includes a shaft  2221  and a plurality of impellers  2223 . The impellers respectively include a plurality of blades  2223   a  circumferentially spaced on the shaft  2221 , and are separately received in the receiving recesses  2213   a  of the frame sections  2213 . The frame  221  further includes a first end plate  2215  and a second end plate  2216  that are separately located at two opposite ends of the frame  221 . The first and the second end plate  2215 ,  2216  respectively have a shaft hole  2217  provided thereon. The shaft  2221  is sequentially extended through the impellers  2223  with two opposite ends of the shaft  2221  extending into the two shaft holes  2217 . 
     The cross-flow fan  22  further includes a motor  23 , which is arranged to one side of the first end plate  2215  or the second end plate  2216  and is connected to the centrifugal fan blade assembly  222  for driving the latter to rotate. When the motor  23  of the cross-flow fan  22  drives the centrifugal fan blade assembly  222  to rotate, air outside the frame  221  is guided into the receiving recesses  2213   a  via the air inlets  2211  to flow through the fan impellers  2223  before being blown out of the frame  221  via the air outlet  2212  and forced into the heat radiation unit  21  via the air-in side  213  thereof. The air forced into the heat radiation unit  21  flows through the air-guiding passages  212  between the radiating fins  211  toward the air-out side  214 . The heat transferred from the heat-dissipating section  202  to the radiating fins  211  will be carried away by the air to dissipate into external environment via the air-out side  214 , so as to provide enhanced heat dissipation performance and achieve good heat dissipation effect. 
     With the design of the present invention, the centrifugal fan blade assembly  222  and the shaft  2221  can still extend transversely in a limited mounting space, so that the cross-flow fan  22  not only creates largely increased air flow volume and accordingly upgraded heat dissipation performance, but also effectively enables reduced volume of the fan module  2 . Further, the present invention also overcomes the problems of vibration and noise caused by the swaying long blades in the conventional fan module designed for increasing heat dissipation performance. 
       FIGS. 3A and 3B  are exploded and assembled perspective views, respectively, of a fan module according to a second embodiment of the present invention. As shown, the fan module in the second embodiment is generally structurally similar to the first embodiment, except that, in the second embodiment, the cross-flow fan  22  further includes at least one side plate  2218 , which is arranged at the air outlet  2212  of the frame  221  against the air-in side  213  of the heat radiation unit  21 . When the motor  23  of the cross-flow fan  22  drives the centrifugal fan blade assembly  222  to rotate, air outside the frame  221  is guided into the receiving recesses  2213   a  via the air inlets  2211  to flow through the fan impellers  2223  before being blown out of the frame  221  and forced into the heat radiation unit  21  via the air-in side  213  thereof. The air forced into the heat radiation unit  21  flows through the air-guiding passages  212  between the radiating fins  211  toward the air-out side  214 . Meanwhile, heat will be carried away from the radiating fins  211  by the air to the air-out side  214  and be dissipated into external environment, so as to provide enhanced heat dissipation performance and achieve good heat dissipation effect. 
     Please refer to  FIG. 4  that is an assembled perspective view of a fan module according to a third embodiment of the present invention. As shown, the fan module in the third embodiment is generally structurally similar to the previous embodiments, except that, in the third embodiment, two or more cross-flow fans  22  are parallelly arranged side by side. With this arrangement, the heat can also be carried away from the radiating fins  211  by air flows to the air-out side  214  of the heat radiation unit  21  and be dissipated into external environment to achieve the purpose of heat dissipation. In the illustrated third embodiment, two cross-flow fans  22  are shown. However, it is understood the number of the cross-flow fans  22  is not necessarily limited to two. 
     According to the above description, the fan module of the present invention is superior to the conventional one because it has largely reduced overall volume, eliminates the occurrence of vibration and noise during operation, and provides enhanced heat dissipation performance. 
     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.