Patent Publication Number: US-8992174-B2

Title: Fan assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This Application claims priority of Taiwan Patent Application No. 100102548, filed on Jan. 25, 2011, the entirety of which is incorporated by reference herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a fan assembly, and in particular, to a fan assembly utilizing a centrifugal fan to generate an airflow to a channel structure, wherein the airflow flows out from the channel structure. 
     2. Description of the Related Art 
     A conventional household fan utilizes a motor to drive an axial-flow fan to rotate, and then an airflow is generated by the rotating axial-flow fan. The household fan has large blades to generate enough airflow. However, the larger blades have greater torque, and an extending direction and a rotating direction of the blade have an acute angle therebetween. Thus, it is very dangerous; especially if children touch the rotating blades. 
     To solve the above problem, US Patent App. publication No. 20090060710 discloses a fan  100  as shown in  FIG. 1 . An axial-flow fan  110  is disposed in a base  120 , and air is drawn via an air inlet  121  of the side wall of the base  120 . The air flows into an annular nozzle  130  along a flow path F 1 . Finally, the air flows out from the annular nozzle  130  and is discharged at the inner side of the annular nozzle  130  to flow along a flow direction D 1 . 
     Because the axial-flow fan  110  is disposed in the base  120 , children cannot touch the axial-flow fan  110 . Moreover, the inner side of the annular nozzle  130  is a hollow space, and thus the annular nozzle  130  will not block light due to the hollow space. 
     However, the above design has many disadvantages, and thus the exhaust efficiency of the fan  100  is very weak. In  FIG. 1 , the axial-flow fan  110  draws air along the axial direction and generates airflow along the axial direction. Since the blade of the axial-flow fan  100  is disposed downwardly, and the motor  111  is located between the blade and the annular nozzle  130 , the airflow is guided upwardly to the annular nozzle  130 . However, all of the components (such as the motor  111 ) of the axial-flow fan  110  will occupy almost all of the space inside of the base  120 , and thus the airflow will flow in a narrow channel G. Thus, the exhaust efficiency is decreased because the airflow is blocked in the narrow channel G. Moreover, the air inlet  121  is disposed on the side wall of the base  120 , and the direction of air flowing into the air inlet  121  via the side wall is perpendicular to the intake direction of airflow toward the annular nozzle  130 . Thus, the intake efficiency is decreased. 
     Please also refer to  FIG. 2 , which is an enlarged view of the part A of  FIG. 1 . The annular nozzle  130  has an air outlet  132  disposed at the intake side  131 , and thus the airflow flowing out from the air outlet  132  will flow from the intake side  131  to the exhaust side  133 . In the figures, the airflow is blocked by the annular inner side wall of the annular nozzle  130 , and the airflow volume of the air outlet  132  is decreased. Moreover, since the airflow of the annular nozzle  130  flows out from the air outlet  132  after rotation, the wind pressure and the exhaust airflow volume are decreased hugely. Thus, the exhaust efficiency of the fan  100  is decreased. 
     BRIEF SUMMARY OF THE INVENTION 
     To solve above problems of the prior art, the object of the invention is to provide a fan assembly. The fan assemble utilizes a centrifugal fan and an improved channel structure to raise the exhaust efficiency and has the advantages of the prior art. 
     For the above object, an embodiment of the invention provides a fan assembly including a channel structure and a centrifugal fan. The channel structure includes a housing and at least one slit. The housing includes an accommodating space and a flow channel adjacent to each other. The slit is extended along the flow channel, wherein the flow channel is communicated with an outside of the housing via the slit. The centrifugal fan is disposed in the accommodating space, and the centrifugal fan draws air along an axial direction of the centrifugal fan and generates an airflow into the flow channel along a radial direction of the centrifugal fan. The airflow flows out from the slit to the outside of the housing. 
     In an embodiment, the housing includes at least one air inlet corresponding to the centrifugal fan in the axial direction, and the centrifugal fan draws air from the outside of the housing via the air inlet along the axial direction. 
     In an embodiment, the channel structure includes at least one guide channel adjacent to the centrifugal fan. The speed of the airflow generated by the centrifugal fan can be increased by the guide channel. The guide channel guides the airflow generated by the centrifugal fan to enter the flow channel along the radial direction. 
     In an embodiment, the guide channel includes a first guide channel and a second guide channel. The airflow guided by the first guide channel flows along a first direction, and the airflow guided by the second guide channel flows along a second direction. The first direction is different from the second direction. 
     In an embodiment, the channel structure includes a separator. The first guide channel and the second guide channel are separated by the separator, and the first guide channel and the second guide channel are crossed in the axial direction. 
     In an embodiment, the channel structure is substantially an annular structure, and the first guide channel guides the airflow to flow into the flow channel of the annular structure along a clockwise direction. The second guide channel guides the airflow to flow into the flow channel of the annular structure along a counter clockwise direction. 
     In an embodiment, the centrifugal fan includes a motor, a hub, a plurality of first blades and a plurality of second blades. The motor is disposed in the hub. The first blades and the second blades are disposed around the hub corresponding to the first guide channel and the second guide channel, respectively. 
     In an embodiment, the centrifugal fan further includes a connection element in the shape of a disk. The connection element is connected to the hub and the first and second blades. The connection element is disposed between the first and second blades. 
     In an embodiment, the centrifugal fan includes a first motor, a first hub, a plurality of first blades, a second motor, a second hub, and a plurality of second blades. The first motor, the first hub and the first blades correspond to the first guide channel. The second motor, the second hub and the second blades correspond to the second guide channel. The first and second motors are disposed in the first and second hubs, respectively. The first and second blades are disposed around the first and second hubs, respectively. 
     In an embodiment, the first and second motors are separated by the separator. 
     In an embodiment, the flow channel includes a channel portion and a gradually narrowed terminal portion. 
     In an embodiment, the terminal portion is gradually narrowed from an end of the terminal portion close to the channel portion to another end of the terminal portion away from the channel portion. The slit is disposed on an edge of the terminal portion away from channel portion. 
     In an embodiment, the slit is disposed on the channel portion, and the housing has an overlapped part parallel to a flowing direction of the airflow adjacent to the slit. 
     In an embodiment, the channel structure is substantially an annular structure. An inner side of the annular structure has an air space. The slit is extended around the inner side of the annular structure and the air space. 
     In an embodiment, the fan assembly further includes a base. The channel structure is supported by the base. 
     In an embodiment, the centrifugal fan is disposed at an end of the channel structure adjacent to the base, or at another end of the channel structure opposite to the base. 
     In an embodiment, the channel structure includes a plurality of annular structures. The centrifugal fan is disposed at a connecting portion of the annular structures. 
     In an embodiment, the channel structure includes an annular structure and a plurality of guide structures. The guide structures are connected to an inner annular surface of the annular structure. The centrifugal fan is disposed on a connecting portion of the guide structure and located at the center of the annular structure. 
     In an embodiment, the guide structures include a first guide structure along a longitudinal direction and a second guide structure along a transverse direction. 
     In an embodiment, the channel structure is substantially an annular structure. The annular structure has an air space therein. The air space has an intake side and an exhaust side. When the airflow flows out from the slit to the outside of the housing, air is driven in the air space to move from the intake side to the exhaust side. Moreover, the direction of the airflow flowing out from the slit is the same as the direction of the air moving in the air space. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG. 1  is a cross-sectional view of a conventional fan; 
         FIG. 2  is an enlarged view of the part A of  FIG. 1 ; 
         FIG. 3  is a perspective view of a fan assembly of the first embodiment of the invention; 
         FIG. 4  is a cross-sectional view of a fan assembly of the first embodiment of the invention; 
         FIG. 5  is a partially cross-sectional view of the channel structure of the second embodiment of the invention; 
         FIG. 6  is a partially cross-sectional view of the channel structure of the third embodiment of the invention; 
         FIG. 7  is a schematic diagram of the fan assembly of the fourth embodiment of the invention; 
         FIG. 8  is a cross-sectional view along the line AA of  FIG. 7 ; 
         FIG. 9  is a schematic diagram of the fan assembly of the fifth embodiment of the invention; 
         FIG. 10  is a schematic diagram of the fan assembly of the sixth embodiment of the invention; 
         FIG. 11  is a schematic diagram of the fan assembly of the seventh embodiment of the invention; and 
         FIG. 12  is a schematic diagram of the fan assembly of the eighth embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 3 and 4 , a fan assembly  1  includes a base  200 , a channel structure  300  and a centrifugal fan  400 . The base  200  can be disposed on the ground or a table. The channel structure  300  is supported by the base  200 . The channel structure  300  includes a housing  300 ′ and at least a slit  321 . The housing  300 ′ is a hollow annular structure. The housing  300 ′ has an accommodating space  307  and a flow channel  304  therein. The flow channel  304  and accommodating space  307  are adjacent to each other. The slit  321  is extended along the flow channel  304 . The flow channel  304  is communicated with the outside of the housing  300 ′ via the slit  321 . The centrifugal fan  400  is disposed in the accommodating space  307 . The centrifugal fan  400  draws air along an axial direction D 3 , and generates an airflow to the flow channel  304  along an radial direction D 3   a . Next, the airflow flows out of the housing  300 ′ via the slit  321 . 
     The housing  300 ′ of the channel structure  300  further includes a plurality of air inlets  308 . The accommodating space  307  is communicated with the flow channel  304  and the air inlets  308 . The air inlets  308  correspond to the centrifugal fan  400  in the axial direction D 3 , and the centrifugal fan  400  can draw air from the outside of the housing  300 ′. 
     The channel structure  300  is substantially an annular structure. The channel structure  300  has an air space S 1  therein. The slit  321  is disposed around the inner side of the annular structure, and the slit  321  encloses the air space S 1 . The annular structure of the housing  300 ′ has an inner side wall  306 , which is adjacent to the flow channel  304 , at the inner side of the annular structure. The annular structure has an outer side wall  305  at the outer side of the annular structure. The channel structure  300  is disposed on the base  200 . The centrifugal fan  400  is disposed in the channel structure  300  adjacent to an end of the base  200 . The airflow generated by the centrifugal fan  400  flows out from the slit  321  of the channel structure  300 , and the airflow drives the air in the air space S 1  to move from an intake side  301  to an exhaust side  302  along the flow direction D 2 . 
     The flow channel  304  has a channel portion  310  and a terminal portion  320 . The flow channel  304  is formed in the inside of the channel portion  310  and the terminal portion  320 . The channel portion  310  is a U shaped structure and is close to the intake side  301 . The terminal portion  320  is close to the exhaust side  302  and connected to the channel portion  310 . The terminal portion  320  is a V-shaped structure. The terminal portion  320  is gradually narrowed from the intake side  301  to the exhaust side  302 . The cross section of the channel portion  310  is substantially in a rectangular shape. The slit  321  is disposed at an edge of the terminal portion  320  away from the channel portion  310 . 
     When the airflow generated by the centrifugal fan  400  flows to the flow channel  304  in the channel structure  300 , the airflow will flow out from the terminal portion  320  or the slit  321  of the channel portion  310 . Therefore, the pressure of the airflow is raised, and the air in the air space S 1  moves from the intake side  301  to the exhaust side  302 . In the embodiment, the airflow between the flow channel  304  and the slit  321  is smooth, and the airflow does not flow to the slit  321  during rotation as the prior art. Therefore, the exhaust airflow volume of the fan assembly is greater. 
     In the embodiment, the centrifugal fan  400  includes a motor  410  and an impeller  420 . The motor  410  and the impeller  420  are disposed in the accommodating space  307 . The motor  410  includes a shaft  411  along a rotating axis AX 1 . The shaft  411  drives the impeller  420  to rotate about the rotating axis AX 1 . Alternatively, the centrifugal fan  400  includes a fan case (not labeled), and the inside of the fan case is the accommodating space  307 . 
     When the impeller  420  is rotated, the centrifugal fan  400  draws air to the impeller  420  along the axial direction D 3 , which is parallel to the rotating axis AX 1 . Then the airflow flows toward the flow channel  304  along the radial direction D 3   a . The radial direction D 3   a  is perpendicular to the rotating axis AX 1  in the figure. Finally, the airflow flows out from the housing  300 ′ via the slit  321 . In  FIG. 4 , the air inlets  308  correspond to the impeller  420 . Namely, the air inlets  308  are arranged in parallel to the inlet surface  422  of the impeller  420 . Therefore, when the impeller  420  is rotated, the air is drawn from the air inlets  308  along the axial direction D 3  without being blocked by any component. The airflow intake efficiency of the fan assembly  1  is improved compared to the prior art. 
       FIG. 5  is a partially cross-sectional view of the channel structure of the second embodiment of the invention. The difference between the second embodiment and the first embodiment is described below. The cross section of the flow channel  304   a  is in a winged shape. The cross section of a channel portion  310   a  is in an arc shape. The edge of a terminal portion  320   a  is tilted, and the cross section of an inner side wall  306   a  of a housing  300   a ′ is extended straightly along a direction that is substantially parallel to the flow direction D 2 . By the above structure, the airflow flows out from the slit  321   a  more easily, and the air in the air space S 1  flows smoothly. 
       FIG. 6  is a partially cross-sectional view of the channel structure of the third embodiment of the invention. The difference between the third embodiment and the first embodiment is described below. The cross section of a flow channel  304   b  is in a winged shape. The cross section of a channel portion  310   b  is substantially in an arc shape, and the cross section of a terminal portion  320   b  is in a V shape. 
     A slit  321   b  is disposed on the channel portion  310 . The channel portion  310  further includes a slit channel  322  communicated with the slit  321   b . The housing  300   b ′ has an overlapped part parallel to a flowing direction of the airflow adjacent to the slit  321   b . The inner side wall  306   b  of the housing  300 ′ includes a first inner wall  3061  and a second inner wall  3062  adjacent to the flow channel  304   b  at the inner side wall  306   b  of the housing  300   b ′. The first inner wall  3061  and the second inner wall  3062  are substantially parallel to the flow direction D 2  and overlapped to each other. The overlapped part of the first inner wall  3061  and the second inner wall  3062  forms the slit channel  322 , and thus the slit channel  322  is substantially parallel to the flow direction D 2 . The slit  321   b  is formed at the edge of the slit channel  322 . By the above structure, the airflow flows out from the slit  321   b  more easily, and the air in the air space S 1  flows more smoothly. 
     Please refer to  FIGS. 7 and 8 .  FIG. 7  is a schematic diagram of the fan assembly of the fourth embodiment of the invention.  FIG. 8  is a cross-sectional view along the line AA of  FIG. 7 . The difference between the fourth embodiment and the first embodiment is described below. A channel structure  300   c  includes a first guide channel  330  and a second guide channel  340 . The first guide channel  330  and the second guide channel  340  are adjacent to a centrifugal fan  400   c , and guide the airflow generated by the centrifugal fan  400   c  to flow into the flow channel  304  along the radial direction. The airflow guiding direction of the first guide channel  330  is different from that of the second guide channel  340 . The centrifugal fan  400   c  further includes a fan case  430 . The fan case  430  has a separator  431  therein. The inside of the fan case  430  is divided into a first space S 2  and a second space S 3  by the separator  431 . The fan case  430  also has a first flow inlet  432  and a second flow inlet  433 . The first flow inlet  432  is communicated with the first space S 2 . The second flow inlet  433  is communicated with the second space S 3 . The impeller  420  is disposed in the fan case  430  and generates airflow. 
     In the embodiment, an impeller  420   c  includes a hub  423 , a connection element  424 , a plurality of first blades  425 , and a plurality of second blades  426 . A motor  410   c  is disposed in the hub  420   c . The first blades  425  and the second blades  426  are disposed around the hub  423 . One side of the hub  423  is close to the first flow inlet  432 . The other side of the hub  423  is close to the second flow inlet  433 . The connection element  424  is disk-shaped. An inner end of the connection element  424  is connected to the hub  423  and an outer end of the connection element  424  is connected to the first blades  425  and the second blades  426 . The first blades  425  and the second blades  426  are disposed on two opposite sides of the connection element  424 , respectively. Namely, the connection element  424  is disposed between the first blades  425  and the second blades  426 . The first flow inlet  432  is close to the first blades  425 , and the second flow inlet  433  is close to the second blades  426 . 
     The inside of the fan case  430  is divided into the first space S 2  and the second space S 3  by the connection element  424  and the separator  431 . The separator  431  can further separate the first guide channel  330  from the second guide channel  340 . Moreover, the first blades  425  are located at the first space S 2  and correspond to the first guide channel  330 . The second blades  426  are located at the second space S 3  and correspond to the second guide channel  340 . The airflow generated by the first blades  425  and the second blades  426  flows to the first space S 2  as a first airflow, and flows to the second space S 3  as a second airflow. 
     The first guide channel  330  is communicated with the first space S 2  and the flow channel  304 , and the second guide channel  340  is communicated with the second space S 3  and the flow channel  304 . The first guide channel  330  and the second guide channel  340  are crossed in an inlet direction, which can be the axial direction, of the centrifugal fan  400   c . Namely, the first airflow flows into the flow channel  304  via the first guide channel  330  so that the first airflow is guided to flow along a first direction D 5 . The second airflow flows into the flow channel  304  via the second guide channel  340  so that the second airflow is guided to flow along a second direction D 6 . The second direction D 6  is different from the first direction D 5 . Thus, the speed of the airflow generated by the centrifugal fan  400   c  can be increased. Because the flow channel  304  is an annular structure, the first direction D 5  may be a counter clockwise direction and the second direction D 6  may be a clockwise direction. Alternatively, the first direction D 5  may be a clockwise direction, and the second direction D 6  may be a counter clockwise. 
     Please refer to  FIG. 9 , which is a schematic diagram of the fan assembly of the fifth embodiment of the invention. The difference between the fifth embodiment and the fourth embodiment is described below. A fan case  430   d  is separated into a first space S 2  and a second space S 3  only by a separator  431   d . A centrifugal fan  400   d  includes a first motor  410   d  and a first impeller  420   d  corresponding to the first guide channel  330  (shown in  FIG. 7 ). The centrifugal fan  400   d  further includes a second motor  410   e  and a second impeller  420   e  corresponding to the second guide channel  340  (shown in  FIG. 7 ). The first motor  410   d  and the second motor  410   e  are separated by the separator  431   d , and a first hub  423   d  and a second hub  423   d  are separated by the separator  431   d , too. The first impeller  420   d  and the second impeller  420   e  are disposed in the first space S 2  and the second space S 3 . The first impeller  420   d  includes the first hub  423   d  and a plurality of first blades  425   d . The second impeller  420   e  includes the second hub  423   e  and a plurality of second blades  425   e . The first motor  410   d  and the second motor  410   e  are disposed in the first hub  423   d  and the second hub  423   e , respectively. The first blades  425   d  and the second blades  425   e  are disposed around the first hub  423   d  and the second hub  423   e , respectively. The first impeller  420   d  and the second impeller  420   e  are rotated in opposite directions. 
     Accordingly, by the separated channels, the airflow can be guided into the flow channels in opposite directions by the centrifugal fans of the fourth and the fifth embodiments. The airflow can be guided more efficiently in contrast to the prior art, wherein the airflow flows to the flow channel in a single direction. 
     Please refer to  FIG. 10 , which is a schematic diagram of a fan assembly if of the sixth embodiment of the invention. The difference between the sixth embodiment and the first embodiment is described below. A centrifugal fan  400   f  is disposed at the other end, opposite to a base  200   f , of a channel structure  300   f . The centrifugal fan  400   f  is disposed at the top side of the channel structure  300   f . The centrifugal fan  400   f  can be disposed horizontally, so the axial direction D 4  can be vertically downward, as shown in  FIG. 10 . Therefore, the centrifugal fan  400   f  can be disposed at a high position to prevent children from touching. Furthermore, a flow channel  304   f  is an annular structure in a C shape, and the two opposite sides of the centrifugal fan  400   f  are close to the two ends of the flow channel  304   f . Namely, the centrifugal fan  400   f  generates the airflow to the two ends of the flow channel  304   f . Therefore, the exhaust efficiency can be further improved. 
     Please refer to  FIG. 11 , which is a schematic diagram of a fan assembly  1   g  of the seventh embodiment of the invention. The difference between the seventh embodiment and the first embodiment is described below. A channel structure  300   g  is constituted by a plurality of annular structures  300   h . A centrifugal fan  400   g  is disposed on the connecting portion of the annular structures  300   h . The annular structures  300   h  are disposed around the centrifugal fan  400   g . The connecting portion of the annular structures  300   h  has an accommodating space  307   g . The accommodating space  307   g  is communicated with a plurality of flow channels  304   g  of the annular structures  300   h . The centrifugal fan  400   g  is disposed in the accommodating space  307   g . The annular structures  300   h  are disposed at the same plane or at different planes. When the annular structures  300   h  are disposed at the same plane, the area of a slit  321   g  is increased and the area of the cross section of all of the flow channels  304   g  is increased. Thus, the airflow of the fan assembly  1   g  can be increased by raising the rotating speed of the centrifugal fan  400   g . When the annular structures  300   h  are disposed at different planes, the airflow of the fan assembly  1   g  can be increased and the airflow can flow in different directions. Thus, the flowing area of the airflow can be increased. 
     Please refer to  FIG. 12 , which is a schematic view of a fan assembly  1   i  of the eighth embodiment of the invention. The difference between the eighth embodiment and the seventh embodiment is described below. The channel structure  300   i  includes an annular structure  3001  and a plurality of guide structures  3002 , and  3003 . The guide structures  3002  and  3003  are connected to the inner annular surface  3001   a  of the annular structure  3001 . A centrifugal fan  400   i  is disposed on a jointing portion of the guide structures  3002  and  3003  at the center of the annular structure  3001 . The guide structures  3002  can be extended along a longitudinal direction D 7 , and the guide structures  3003  can be extended along a transverse direction D 8 . The extending path of the guide structures  3002  and  3003  can be combined or separated. The slit  321   i  may be extended along the extending path of the guide structures  3002 , and  3003 . 
     In conclusion, since the invention utilizes the centrifugal fan and the improved channel structure, the space between the blade of the centrifugal fan and the flow channel will not be blocked by any component, such as a motor. In the invention, the airflow generated by the centrifugal fan can be guided by the guide channels directly without any bended path and may not be blocked by the motor as the prior art. The guide channel does not have to bend because of components such as a motor, and thus the airflow can flow smoothly. Moreover, the speed of the airflow generated by the centrifugal fan can be increased due to the guide channels of the invention. Preferably, the first and the second guide channels of the invention are stacked to each other, and thus the airflow can be guided to the flow channel in clockwise and counterclockwise directions respectively by the first and the second guide channels. Compared with the prior art wherein the airflow can be transmitted to the annular nozzle only in a single direction, the airflow of the invention can be transmitted more efficiently in two opposite directions. 
     While the invention has been described by way of example and in terms of preferred embodiment, 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.