Abstract:
A centrifugal fan apparatus is disclosed in the present invention. The characteristics of the centrifugal fan apparatus lies in that the width of airflow channel defined between the rim of the impeller and the inner wall of the housing accommodating the impeller is uniform, and two airflow spaces defined between the axial cross section of the impeller and upper housing and lower housing respectively are not symmetry. Due to these two characteristics, the centrifugal fan apparatus is capable of making larger pressure difference to inducing higher flow rate and reducing noise while the centrifugal fan apparatus is operated. The present invention also provides a dust-collecting module that is formed by adopting the centrifugal fan apparatus with a designed dust-collecting casing, which is capable of being a sucker of a vacuum cleaner to collect dust of the surroundings for the purpose of environment cleaning.

Description:
CROSS REFERENCE TO RELATED PATENT APPLICATION 
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 11/536,285 filed on Sep. 28, 2006. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a centrifugal fan apparatus, and more particularly, to a low noise, high flow rate centrifugal fan apparatus with asymmetry fan housing design, which has an uniform airflow channel formed between the rim of its impeller and its housing, and is applicable to a dust-collecting module. 
       BACKGROUND OF THE INVENTION 
       [0003]    An autonomous vacuum cleaner, being a fully automated cleaning device, is a renovating device different from those conventionally vacuum cleaners and other sweeping devices, that is can clean a specific area autonomously without any human attention and thus is foreseen to be the future cleaning device replacing those conventional manual-operated vacuum cleaners and other cleaning devices. After the operation mode is set, an autonomous vacuum cleaner is able to maneuver around obstacles while performing a ground cleaning operation, even cleaning those usually considered as the dead spots of cleaning 
         [0004]    Although the autonomous vacuum cleaner is a great help to daily household cleaning, its function is limited by its power source, which is not an alternating current (AC) power source, and by its own interior space, which limited the same from adopting those air compressors used in those conventional vacuum cleaners. Therefore, as the autonomous vacuum cleaner only has limited power supply, a good centrifugal fan is essential for enabling the same to have good performance. Nonetheless, the centrifugal fan is beneficial for its operating noise is lower than those conventional air compressors. 
         [0005]    It is noted that current design of a centrifugal fan is focusing on low noise, high pressure difference and large flow rate while maintaining smooth operation. One such design is disclosed in TW Pat. No. M246471, which shows a centrifugal fan device and a vacuum cleaner adopting the same. However, as the housing of the aforesaid centrifugal fan device is not improved while no proper deflector is available in the airflow channel, it is prone to generate noise. Another such design is disclosed in EPC Pat. No. EP0943808, in which its casing is designed for enabling its air pressure cavity to run spirally to an outflow aperture whereas its casing tongue is made with a through curvature for separating the airflow of the intake end from that of the outflow end so that the efficiency of the aforesaid centrifugal fan device can be improved as turbulence is avoided. 
         [0006]    Generally, in those disclosed centrifugal fan devices, the convenience of attaching a dust-collecting box upon a centrifugal fan device is mostly cancelled out by the blocking of the smoothness of air flow in the centrifugal fan device&#39;s airflow channel. 
         [0007]    Therefore, it is in need of an improved centrifugal fan apparatus and a dust-collecting module that are freed from the foregoing drawbacks. 
       SUMMARY OF THE INVENTION 
       [0008]    It is the primary object of the present invention to provide a low noise, high flow rate centrifugal fan apparatus with asymmetry fan housing design, which has an uniform airflow channel formed between the rim of its impeller and its housing, and is applicable to a dust-collecting module. 
         [0009]    Another object of the invention is to provide a dust-collecting module capable of utilizing it specially designed casing to assemble a centrifugal fan apparatus of the invention so as to be able to perform a dust-collecting operation while maintaining the smoothness of airflow in the centrifugal fan apparatus. 
         [0010]    To achieve the above objects, the present invention provides a centrifugal fan apparatus, comprising: a housing with an accommodating space, having an intake hole and an outflow hole; an impeller, arranging in the accommodating space while enabling an airflow channel of uniform width to be formed between a rim of the impeller and a side wall of the housing; and a driving device, connected to the impeller for driving the same to rotate. 
         [0011]    Preferably, the accommodating space is divided into a first space and a second space by a virtual cross section passing the axial center of the impeller, referring as axial cross section hereinafter, whereas the first space is asymmetrical to the second space. Moreover, a helical airflow channel is extending from the second space and channeling to the outflow hole; and the sectional area of the helical airflow channel is increasing progressively from the beginning thereof to the outflow hole. 
         [0012]    Preferably, the housing further is composed of: a top shell, having the intake hole formed thereon; and a bottom shell, having the outflow hole formed therein, being connected to the top shell. 
         [0013]    Preferably, each blade used in the impeller is a blade selected from the group consisting of airfoil blades of signal-blade design and airfoil blades of dual-blade design. 
         [0014]    In a preferred aspect, to achieve the above objects, the present invention provides a centrifugal fan apparatus, comprising: a housing with an accommodating space, having an intake hole and an outflow hole; an impeller, arranging in the accommodating space while enabling the accommodating space to be divided into a first space and a second space by a virtual cross section passing the axial center of the impeller, referring as axial cross section hereinafter, whereas the first space is asymmetrical to the second space; and a driving device, connected to the impeller for driving the same to rotate. 
         [0015]    In addition, the present invention further provides a ducts-collecting module, comprising: a case, having a recess and a through hole channeling to the recess, and a side thereof being arranged with a groove hole channeling to the recess; a dust-collecting lid, connected to the groove hole; a box with a dust-collecting space, capable of being received in the recess for enabling the duct-collecting space to channel with the through hole and the groove hole; and a centrifugal fan apparatus, arranged upon the case, further comprising: a housing with an accommodating space formed therein, having an intake hole connected to the through hole and an outflow hole; an impeller, arranging in the accommodating space while enabling an airflow channel of uniform width to be formed between a rim of the impeller and a side wall of the housing; and a driving device, connected to the impeller for driving the same to rotate. 
         [0016]    Preferably, a filtering device is arranged between the centrifugal fan apparatus and the through hole. 
         [0017]    Preferably, the dust-collecting lid is further comprised of a roller with brush formed thereon. 
         [0018]    Preferably, a plurality of sliding grooves are formed on two side walls of the recess for enabling a plurality of protrusions formed on two sides of the box, corresponding to the two side wall of the recess, to abut against thereupon and thus enabling the box to slide in and out the recess. 
         [0019]    Yet, the present invention further provides a dust-collecting module, which comprises: a case, a case, having a recess and a through hole channeling to the recess, and a side thereof being arranged with a groove hole channeling to the recess; a dust-collecting lid, connected to the groove hole; a box with a dust-collecting space, capable of being received in the recess for enabling the duct-collecting space to channel with the through hole and the groove hole; and a centrifugal fan apparatus, arranged upon the case, further comprising: a housing with an accommodating space formed therein, having an intake hole connected to the through hole and an outflow hole; an impeller, an impeller, arranging in the accommodating space while enabling the accommodating space to be divided into a first space and a second space by a virtual cross section passing the axial center of the impeller, referring as axial cross section hereinafter, whereas the first space is asymmetrical to the second space; and a driving device, connected to the impeller for driving the same to rotate. 
         [0020]    Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1A  is an exploded diagram illustrating a centrifugal fan apparatus according to a preferred embodiment of the invention. 
           [0022]      FIG. 1B  is a schematic diagram showing a centrifugal fan apparatus of the invention. 
           [0023]      FIG. 2A  is a top view of an impeller having airfoil blades of signal-blade design according to the present invention. 
           [0024]      FIG. 2B  is a top view of an impeller having airfoil blades of dual-blade design according to the present invention. 
           [0025]      FIG. 3A  is a top view of a centrifugal fan apparatus according to the present invention. 
           [0026]      FIG. 3B  is a cross sectional view of a centrifugal fan apparatus according to the present invention. 
           [0027]      FIG. 4  is a P-Q curve diagram illustrating the comparison between a centrifugal fan apparatus of the invention and other conventional centrifugal fan apparatuses. 
           [0028]      FIG. 5  is a schematic diagram showing a dust-collecting module according to a preferred embodiment of the invention. 
           [0029]      FIG. 6A  is a schematic diagram showing a case of a ducts-collecting module according to a preferred embodiment of the invention. 
           [0030]      FIG. 6B  is an exploded diagram depicting a case of a ducts-collecting module according to a preferred embodiment of the invention. 
           [0031]      FIG. 7  is a schematic diagram showing a dust-collect lid according to a preferred embodiment of the invention. 
           [0032]      FIG. 8  is a side view of a second embodiment of a centrifugal fan apparatus according to the present invention. 
           [0033]      FIG. 9  is a bottom view of a second embodiment of a centrifugal fan apparatus according to the present invention. 
           [0034]      FIG. 10  is a schematic diagram showing a second of a dust-collecting module according to a preferred embodiment of the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0035]    For your esteemed members of reviewing committee to further understand and recognize the fulfilled functions and structural characteristics of the invention, several preferable embodiments cooperating with detailed description are presented as the follows. 
         [0036]    Please refer to  FIG. 1A  and  FIG. 1B , which are respectively an exploded view and a pictorial view of a centrifugal fan apparatus according to a preferred embodiment of the invention. As seen in  FIG. 1A  and  FIG. 1B , the centrifugal fan apparatus  1  is comprised of a housing  10 , an impeller  11  and a driving device  14 , in which the housing is further composed of a top shell  101  and a bottom shell  102 . Apart from the helical casing, as that disclosed in EPC Pat. No. EP0943808, the axial cross section of an accommodating space formed by the assembling of the top shell  101  and the bottom shell  102  is shaped as a disc, which is different from those of prior arts, whereas an intake hole  1011  is formed at the center of the top shell  101 ; and an outflow hole  1021  is formed at a side of the bottom shell  102 . 
         [0037]    Moreover, the impeller  11  is disposed inside the accommodating space, which is composed of: a back panel  110 ; a plurality of blades  113 , arranged on the back panel  110 ; and a top panel  112 , arranged over the plural blades  113 . The plural blades  113  can be arranged on the back panel  111  by manner as those illustrated in  FIG. 2A  and  FIG. 2B . However, it is only used as illustration and is not limited thereby. In  FIG. 2A , the plural blades  113  are radially arranged while each blade  113  used in the impeller  11  is an airfoil blade of signal-blade design. In  FIG. 2B , the plural blades  113   a,    113   b  are radially arranged while each blade used in the impeller l la are two offset airfoil blades  113   a,    113   b,  i.e. blade of dual-blade design. In addition, the driving device  14  is connected to the impeller  11  by a pin  12  and an interfacing panel  13  so that the impeller  11  can be driven to rotate by the driving device  14 . 
         [0038]    Please refer to  FIG. 3A , which is a top view of a centrifugal fan apparatus according to the present invention. In  FIG. 3A , the manner that the impeller  11  is being arranged inside the housing  10  is illustrated. As the axial cross section of the accommodating space of the housing  10  is shaped like a disc, an airflow channel  103  of uniform width D can be formed between a rim of the impeller  11  and a side wall of the housing  10 . Please refer to  FIG. 3B , which is a cross sectional view of a centrifugal fan apparatus according to the present invention. In  FIG. 3B , the accommodating space is being divided into a first space A 1  and a second space A 2  by a virtual cross section  8  passing the axial center of the impeller  11  while enabling the first space A 1  to be asymmetrical to the second space A 2 . As seen in  FIG. 1B  and  FIG. 3B , a helical airflow channel  1022  is formed in the second space A 2  by the bottom shell  102  whereas the sectional area of the helical airflow channel  1022  is increasing progressively from the beginning thereof to the outflow hole  1021 . In  FIG. 3B , two sections  1022   a,    1022   b  are shown whereas the section  1022   a  is at a position near the outflow hole  1021  and the section  1022   b  is at a position near the beginning thereof, in which the area of the section  1022   a  is larger than that of the section  1022   b.    
         [0039]    As there will be no obvious casing tongue by the housing design of the invention, most of the air flow will be discharged from the portion of the airflow channel under the impeller  11  so that no backflow will be generated between the intake and outflow and thus noise is reduced. Please refer to  FIG. 4 , which is a P-Q curve diagram illustrating the comparison between a centrifugal fan apparatus of the invention and other conventional centrifugal fan apparatuses. In  FIG. 4 , curve  90  represents the P-Q curve of a centrifugal fan apparatus of the invention, marked as MSL II; curve  91  represent the P-Q curve of a centrifugal fan apparatus disclosed in TW Pat. No. M246471, marked as RV-10; and curve  92  represent the P-Q curve of a centrifugal fan apparatus disclosed in EP0943808, marked as Karcher; and curve  93  represent the P-Q curve of a centrifugal fan apparatus of a current product, i.e. I-robot. As seen in  FIG. 4 , the performance of the centrifugal fan device of the invention is better than those other conventional centrifugal fan apparatuses, as the curve  90  is outperforming the curves  91 ,  92 ,  93 . In addition, the overall noise of the invention is about the same as that of Karcher, but is much better than that of RV-10 by about 10dB. Hence, the centrifugal fan apparatus of the invention is considered to be a low noise, high flow rate centrifugal fan apparatus. 
         [0040]    As the aforesaid centrifugal fan apparatus of the invention is capable of providing high flow rate while maintaining high pressure difference, the centrifugal fan apparatus is suitable to be adapted for a duct-collecting module. Please refer to  FIG. 5 , which is a schematic diagram showing a dust-collecting module according to a preferred embodiment of the invention. The duct-collecting module  2  is composed of a centrifugal fan apparatus  20  and a dust-collecting case  21 , in which the centrifugal fan apparatus  20  can be the one disclosed hereinbefore. Please refer to  FIG. 6A  and  FIG. 6B , which are respectively a schematic diagram and an exploded diagram showing a case of a ducts-collecting module according to a preferred embodiment of the invention. The ducts-collecting case  21  further comprises: a case  210 , having a recess  2104  and a through hole  2101  channeling to the recess  2104 ; a dust-collecting lid  212 ; and a box  211 ; wherein, a side of the case  210  is arranged with a groove hole  2102  channeling to the recess  2104 ; the through hole is channeled to the intake hole of the centrifugal fan apparatus  20  while an extractable filtering device is arranged between the through hole  2102  and the centrifugal fan apparatus  20 . 
         [0041]    The box  211  is formed with a dust-collecting space  2110 , which is capable of being received in the recess  2104  as a drawer while enabling the duct-collecting space to channel with the through hole  2102  and the groove hole  2101 . By which, a duct-collecting bag received in the duct-collecting space can be easily accessed and replaced as the box  211  can be easily pulled out of the recess  2104 . Please refer to  FIG. 7 , which is a schematic diagram showing a dust-collect lid according to a preferred embodiment of the invention. As seen in  FIG. 7 , an intake  2121  and an outflow  2120  are formed on the dust-collecting lid  212  while the intake  2121  is channeled with the groove hole  2101  of the case  210 . In addition, a roller, preferred formed with brush, can be arranged at the intake  2121  of the dust-collecting lid  212 . 
         [0042]    In this preferred embodiment of the invention, for enabling air flow to flow smoothly in its airflow channel, the intake hole of its centrifugal fan apparatus is connected to the dust-collecting case  212  through the dust-collecting lid  212  while arranging the opening of the groove hole  2101  of the case  210  at a side thereof instead of at the bottom thereof, by which the airflow channel is not twist for the consideration of improving dust-collecting efficiency and thus noise is reduced. Moreover, as the case  210  and the box  211  are structured as a drawer that the box  211  can be pull out of the case easily, not only it is good for noise reduction, but also it is good for dust cleaning and filer replacing. 
         [0043]    To sum up, the invention can provide a dust-collecting module capable of utilizing it specially designed casing to assemble a low noise, high flow rate centrifugal fan apparatus so as to be able to perform a dust-collecting operation while maintaining the smoothness of airflow in the centrifugal fan apparatus. 
         [0044]    Please refer to  FIG. 8 , which is a side view of a second embodiment of a centrifugal fan apparatus according to the present invention. Please refer to  FIG. 9 , which is a bottom view of a second embodiment of a centrifugal fan apparatus according to the present invention. In  FIG. 8  and  FIG. 9 , the centrifugal fan apparatus is similar to the centrifugal fan apparatus the disclosed in  FIG. 1A  and  FIG. 1B . The difference is the housing  30  having two outflow holes  31  that are respectively formed at two side of the bottom shell  32  and corresponded to each other. The rest structures of the housing  30  in the  FIG. 8  is the same as the housing  10  in the  FIG. 1A . 
         [0045]    In  FIG. 9 , the airflow of each outflow hole  31  is opposite to each other so that the housing  30  is able to keep balance when the airflow flows out of the housing  30 . The advantage of two outflow holes  31  is centrifugal fan apparatus having higher flow rate and lower noise. 
         [0046]    Please refer  FIG. 10 , which is a schematic diagram showing a second of a dust-collecting module according to a preferred embodiment of the invention. In  FIG. 10 , the dust-collecting case  41  is equal to the dust-collecting case  21  in the  FIG. 5 ,  6 A and  6 B. The centrifugal fan apparatus  40  in  FIG. 10  is equal to the centrifugal fan apparatus in the  FIGS. 8 and 9 . Due to the two outflow holes, the dust-collecting module in  FIG. 10  has more efficacy of cleaning and the advantage of higher flow rate and lower noise. 
         [0047]    While the preferred embodiment of the invention has been set forth for the purpose of disclosure, modifications of the disclosed embodiment of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.