Abstract:
Electronic devices and fans thereof are provided. An electronic device comprises a fan cavity and separately disposed heat sources. A fan is disposed in the fan cavity with a frame shaped according to the profile of the fan cavity. The frame also includes an extended portion formed according to the relative position of the fan cavity and separated heat sources, optimizing the heat dissipation.

Description:
BACKGROUND  
       [0001]     The invention relates to fans, and in particular, to fans for electronic devices.  
         [0002]     Typically, when designing an axial fan, airflow outlet/inlet size thereof is increased to raise airflow. Generally, conventional fans utilize a square frame, as shown in  FIG. 1A . Due to limitations of the frame  10 , the extended ramp  11  design of the airflow outlet/inlet cannot be optimized to maximize airflow.  
         [0003]     Conventionally, the center of the fan is aligned with a heat source to optimize heat dissipation.  FIG. 1B  is a sectional diagram of the fan frame in  FIG. 1A  along line a-a.  FIG. 1B  shows an airflow field generated by the fan in  FIG. 1A . In  FIG. 1B , the notation ‘w’ represents the airflow field, ‘ 13 ’ represents the center line of the fan, and ‘ 1   a ’ represents a heat source. The fan is disposed in system  1 , and the heat source la is on the center line  13 .  
         [0004]     The heat source  1   a  cannot always be directly on the center line  13  of the fan because other components in the system occupy the same space. In such cases, a new fan of a larger size or with a higher rotational speed is required, raising production costs and generating relatively more noise.  
         [0005]     Accordingly, U.S. Pat. No. 6,386,843 discloses a fan capable of dissipating heat from a plurality of heat sources. Referring to  FIG. 2 , the fan  20  has a ramp  21  formed on the frame and an extended portion  22  on its side, thereby improving heat dissipation capability. The shape of the frame is basically square. Thus, the square frame is not suitable when system space is limited.  
       SUMMARY  
       [0006]     Fans and electronic devices utilizing the same are provided. An exemplary embodiment of an electronic device comprises a housing, a heat source, and a fan. The housing comprises a fan cavity. The heat source is disposed in the housing. The fan is disposed in the fan cavity. The fan comprises a frame. The frame comprises an airflow outlet, an airflow inlet, and a first extended portion. The first extended portion is disposed at the airflow outlet or the airflow inlet. An inclined angle, an entending direction or a position of the first extended portion is adjusted according to a position or a shape of the fan cavity or the heat source.  
         [0007]     An exemplary embodiment of a fan, for dissipating heat from a heat source, comprises a frame and a blade. The frame comprises an airflow outlet, an airflow inlet, and a first extended portion. The first extended portion is disposed at the airflow outlet or the airflow inlet. An inclined angle, an entending direction or a position of the first extended portion is adjusted according to the position of the heat source. The blade is disposed on the frame.  
         [0008]     Some embodiments of an electronic device comprise a housing, a heat source, and a fan. The heat source is disposed in the housing. The fan is disposed in the housing. The fan comprises a frame with an extended portion near the heat source.  
         [0009]     Some embodiments of an electronic device comprise a housing, a plurality of heat sources, and a fan. The heat sources are disposed in the housing. The fan is disposed in the housing. The fan comprises a frame with an extended portion near each heat source. The extended portion is disposed at an airflow inlet or an airflow outlet of the fan.  
         [0010]     Some embodiments of an electronic device comprise a housing and a fan, wherein the housing comprises a fan cavity with a fan disposed therein. The fan comprises a frame, and the shape of the frame is adjusted according to that of the fan cavity.  
         [0011]     Some embodiments of a fan comprise a frame and a blade. The frame comprises an airflow outlet, an airflow inlet, a first extended portion, and a second extended portion. The first extended portion is disposed at the airflow outlet. The second extended portion is disposed at the airflow inlet. The blade is disposed on the frame. Inclined angles of the first and the second extended portions are different. Extended depths of the first and the second extended portions are different.  
         [0012]     Some embodiments of a fan, for dissipating heat from a heat source, comprise a frame and a blade. The frame comprises an airflow outlet, an airflow inlet, and a first extended portion. The first extended portion is disposed at the airflow outlet. An inclined angle or an entending direction of the first extended portion is adjusted according to a position of the heat source. The blade is disposed on the frame. Sectional areas of the airflow inlet and the airflow outlet are different. Shapes of the airflow inlet and the airflow outlet are different.  
         [0013]     Some embodiments of a fan comprise a frame and a blade. The frame comprises an airflow outlet, an airflow inlet, a first extended portion, and a second extended portion. The first extended portion is disposed at the airflow outlet. The second extended portion is disposed at the airflow inlet. The blade is disposed on the frame. The frame is circular, oval, equilateral polygonal, scalene polygonal, trapezoidal, sectorial, or irregular shaped. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0014]     Fans and electronic devices can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:  
         [0015]      FIG. 1A  is a three-dimensional diagram of a conventional fan frame.  
         [0016]      FIG. 1B  is a sectional diagram of the fan frame in  FIG. 1A  along line a-a.  
         [0017]      FIG. 2  is a top view of a fan disclosed in U.S. Pat. No. 6,386,843.  
         [0018]      FIG. 3A  is a schematic diagram of airflow field related to an embodiment of an electronic device.  
         [0019]      FIG. 3B  is a three-dimensional diagram of the fan frame in  FIG. 3A .  
         [0020]      FIG. 3C  is a sectional diagram of the fan frame in  FIG. 3B  along line b-b.  
         [0021]      FIG. 4A  is a schematic diagram of airflow field related to an embodiment of an electronic device.  
         [0022]      FIG. 4B  is a top view of the fan frame in  FIG. 4A .  
         [0023]      FIG. 4C  is a sectional diagram of the fan frame in  FIG. 4B  along line c-c.  
         [0024]      FIG. 5  is a top view of an embodiment of a fan.  
         [0025]      FIG. 6  is a diagram of an embodiment of a fan frame.  
         [0026]      FIG. 7A  is a schematic diagram of airflow field related to an embodiment of an electronic device.  
         [0027]      FIG. 7B  is a top view of the fan in  FIG. 7A .  
         [0028]      FIG. 7C  is a sectional diagram of the fan frame in  FIG. 7B  along line d-d.  
         [0029]      FIG. 7D  is a sectional diagram of the fan frame in  FIG. 7B  along line e-e.  
         [0030]      FIG. 7E  is a diagram of an embodiment of a fan frame.  
         [0031]      FIG. 7F  is a sectional diagram of the fan frame in  FIG. 7E  along line f-f.  
         [0032]      FIG. 8A  is a top view of an embodiment of a fan frame.  
         [0033]      FIG. 8B  is a schematic diagram of an embodiment of an electronic device utilizing the fan in  FIG. 8A . 
     
    
     DETAILED DESCRIPTION  
       [0034]      FIG. 3A  is a schematic diagram of airflow field related to an embodiment of an electronic device.  FIG. 3B  is a three-dimensional diagram of the fan frame in  FIG. 3A .  FIG. 3C  is a sectional diagram of the fan frame in  FIG. 3B  along line b-b. A stator and a blade are not shown in FIGS.  3 B˜ 3 C for simplicity.  
         [0035]     As shown in  FIG. 3A , the electronic device  2  comprises a housing  2   a , a plurality of heat sources  2   b  and  2   c , and a fan  30 . The heat sources  2   b  and  2   c  and the fan  30  are disposed in the housing  2   a . Due to space limitations, the heat sources  2   b  and  2   c  are disposed separately. The housing  2   a  comprises a fan cavity  2   d  for accommodating the fan  30 . The scope of an airflow field w is modified by adjusting the shape of a frame  31  of the fan for heat dissipation in a limited space.  
         [0036]     As shown in FIGS.  3 A= 18   3 C, the fan  30  is an axial fan with a rectangular frame  31 . The frame  31  comprises an airflow outlet  31   b , an airflow inlet  31   c , two extended portions  31   d  and  31   e , and a bushing  33 . A stator coil  32  is wound at the bushing  33 , and a blade  35  is connected with the bushing  33  through a pivot  34 . The extended portion  31   d  is disposed at the airflow outlet  31   b . The inclined angle of the extended portion  31   d  is adjusted according to the relative position of the fan cavity  2   d  and the heat sources  2   b  and  2   c . Suppose two heat sources spaced the same distance are disposed in  FIGS. 1B and 3A , the airflow field w in  FIG. 3A  is larger due to the extended portion  31   d.    
         [0037]     Referring to  FIGS. 3A and 3D , the extended portion  31   e  is disposed at the airflow outlet  31   c . The two extended portions  31   d  and  31   e  are on the same side. The inclined angle of the extended portion  31   e  is adjusted according to the position of the fan cavity  2   d  for increasing airflow to improve heat dissipation.  
         [0038]     In  FIG. 3B , four positioning holes are formed at the four corners of the frame  31  respectively. The frame  31  can be positioned in the electronic device  2  via the four positioning holes. The locations of the four positioning holes can be adjusted when necessary. In the following disclosed embodiments, the four positioning holes are omitted for simplicity.  
         [0039]      FIG. 4A  is a schematic diagram of airflow field related to an embodiment of an electronic device.  FIG. 4B  is a top view of the fan frame in  FIG. 4A .  FIG. 4C  is a sectional diagram of the fan frame in  FIG. 4B  along line c-c. A stator and a blade are not shown in FIGS.  4 B˜ 4 C for simplicity.  
         [0040]     As shown in  FIG. 4A , the electronic device  3  comprises a housing  3   a , a major heat source  3   b , a minor heat source  3   c , and a fan  40 . The heat sources  3   b  and  3   c  and the fan  40  are disposed in the housing  3   a . The fan faces the major heat source  3   b . In comparison of  FIGS. 3A and 4A , the two heat sources  3   b  and  3   c  are spaced farther (D&gt;p), the fan  40  has an extended portions with larger inclined angles, and thus the scope of the airflow field w in  FIG. 4A  is larger.  
         [0041]     As shown in FIGS.  4 B˜ 4 C, the frame  41  of the fan  40  is similar to the previously described frame  31 . The frame  41  is rectangular. The frame  41  comprises an airflow outlet  41   c , an airflow inlet  41   d , and two extended portions  41   a  and  41   b . The extended portions  41   a  and  41   b  are disposed at the airflow outlet  41   c  and the airflow inlet  41   d  respectively. The main difference between this and previously described frames is that the extended portions  41   a  and  41   b  have different inclined angles (θ 1  and θ 2 ) and extended depths (d 1  and d 2 ). As shown in  FIG. 4C , the extended depths (θ 1  and θ 2 ) are distances from the airflow outlet  41   c  or the airflow inlet  41   d  to the extended portions  41   a  or  41   b . The inclined angles (θ 1  and θ 2 ) represent the included angle between the wall of the extended portions and the connected vertical walls.  
         [0042]     Referring to  FIG. 4A , the extended portions  41   a  and  41   b  are formed with different inclined angles (θ 1  and θ 2 ). Thus, the airflow outlet  41   c  and the airflow inlet  41   d  have different sectional areas and shapes, and the center of the blade is not located at the center of the frame. The frame design can be modified according to positions and sizes of heat sources and the fan cavity, thus optimizing heat dissipation.  
         [0043]      FIG. 5  is a top view of an embodiment of a fan. The fan  50  comprises a frame  51  and a blade  52 , and the frame  51  comprises an extended portion  51   a . The main difference between this and previously described frames is described in the following. The frame  51  is trapezoidal. The extended portion  51   a  is formed along the edges of the airflow outlet or the airflow inlet. The shapes of the airflow outlet and the airflow inlet are basically sectorial for dissipating heat from separated heat sources.  
         [0044]      FIG. 6  is a diagram of an embodiment of a fan frame. The frame  61  comprises an extended portion  61   a  on its two sides, thus adjusting the scope of the airflow field to suit various kinds of heat sources.  
         [0045]      FIG. 7A  is a schematic diagram of airflow field related to an embodiment of an electronic device.  FIG. 7B  is a top view of the fan in  FIG. 7A .  FIG. 7C  is a sectional diagram of the fan frame in  FIG. 7B  along line d-d.  FIG. 7D  is a sectional diagram of the fan frame in  FIG. 7B  along line e-e.  
         [0046]     As shown in  FIG. 7A , the electronic device  4  comprises a housing  4   a  and a plurality of heat sources  4   b  and  4   c . The heat sources  4   b  and  4   c  and the fan  70  are disposed in the housing  4   a . Due to space limitations, the heat sources  4   b  and  4   c  are disposed separately. The housing  4   a  comprises a fan cavity  4   d  on its side for accommodating the fan  70 . The airflow inlet and the airflow outlet are not parallel, so the airflow direction is changed. The scope of an airflow field w is modified by adjusting the shape of a frame  71  of the fan for heat dissipation in limited space.  
         [0047]     As shown in FIGS.  7 A˜ 7 D, the frame  71  comprises an extended portion  71   a  formed at the airflow outlet  71   c  and another extended portion  71   b  formed at the airflow inlet  71   d . The main difference between this and previously described frames is described in the following. The frame  71  is oval. The inclined angles and depths of the extended portions are adjusted according to the heat sources  4   b  and  4   c  and the fan cavity  4   d  in the housing  4   a , thus changing the scope of the airflow field to suit various kinds of heat sources.  
         [0048]      FIG. 7E  is a diagram of an embodiment of a fan frame.  FIG. 7F  is a sectional diagram of the fan frame in  FIG. 7E  along line f-f. As shown in  FIGS. 7E and 7F , the frame  71  of the fan  70  comprises a plurality of segments of different inclined angles. Shapes of any two adjacent segments are different, and axial heights of any two adjacent segments are different. The extended portions  71   a  and  71   b  are disposed at the airflow outlet  71   c . According to heat dissipation requirements, the extended portions  71   a  and  71   b  can comprise a plurality of segments. The distance between each segment and the end of the blade can be different, and height of each segment can be different. Thus, the scope of the airflow field can be adjusted to suit various kinds of heat sources.  
         [0049]     The shape of the frame can be optimized according to the fan cavity in the system.  FIG. 8A  is a top view of an embodiment of a fan frame.  FIG. 8B  is a schematic diagram of an embodiment of an electronic device utilizing the fan in  FIG. 8A .  
         [0050]     In  FIG. 8B , the electronic device  5  comprises a fan cavity  5   a  for accommodation of the fan  80  in  FIG. 8A . The fan cavity  5   a  has an irregular shape. By forming an extended portion  81   a  on the frame  81 , the shape of the frame  81  is changed to suit the fan cavity  5   a . The fan  8  dissipates heat generated by heat sources  5   b ,  5   c , and  5   d.    
         [0051]     The fan cavity  5   a  in  FIG. 8B  can be circular, oval, rectangular, trapezoidal, sectorial, equilateral polygonal, scalene polygonal, or irregular shaped, and the shape of the frame  81  can be changed accordingly.  
         [0052]     While the invention has been described by way of example and in terms of several embodiments, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.