Abstract:
Disclosed herein is a blowing device for small-sized electronic appliances such as cleaning apparatuses. The blowing device comprises a housing, a centrifugal impeller, a guide vane, and a motor for rotating the centrifugal impeller. The centrifugal impeller comprises a shroud, a hub, and a plurality of impeller blades which have an average diameter 87˜93% of a diameter of the housing. The shroud and the hub of the centrifugal impeller, and the guide vane are optimally designed with respect to a size of the housing or an average diameter of the impeller blades, maximizing fan efficiency and heat dissipation of the motor.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a blowing device for small-sized electronic appliances such as cleaning apparatus, and, in particular, to a blowing device which comprises a centrifugal impeller and a guide vane optimally designed to maximize fan efficiency and heat dissipation of a motor without a diffuser.  
         [0003]     2. Description of the Related Art  
         [0004]      FIG. 1  is a perspective view illustrating a conventional blowing device, and  FIG. 2  is a cross-sectional view illustrating a main component of the conventional blowing device.  
         [0005]     The conventional blowing device comprises a housing  4  having an intake port  1  and a discharge port  2 , a centrifugal impeller  10  rotatably equipped within the housing  4 , and a motor  20  connected to the centrifugal impeller  10  via a shaft  21  to rotate the centrifugal impeller  10 .  
         [0006]     The intake port  1  of the housing  4  is located at the center of a front side of the housing  4 , and the discharge port  2  of the housing  4  is located at a rear side of the housing  4 .  
         [0007]     The centrifugal impeller  10  acts to blow air in a centrifugal direction. The centrifugal impeller  10  comprises a shroud  12  having an inlet  12 ′ communicated with the intake port  1  of the housing  4 , a hub  14  separated from the shroud  12  in an axial direction while being coupled to the shaft  21  of the motor  20  to integrally rotate with the shaft  21 , and a plurality of blades  16  radially disposed between the shroud  12  and the hub  14 .  
         [0008]     As the floor area ratio of the centrifugal impeller  10  to the housing  4  is increased, the centrifugal impeller  10  can have an increased blowing capacity. However, if the floor area ratio of the centrifugal impeller  10  to the housing  4  is excessive, the centrifugal impeller  10  can interfere with the housing  4 , and in particular, there occurs an increase in flow resistance of air blown from the centrifugal impeller  10  to the discharge port  2  of the housing  4 . Accordingly, the centrifugal impeller  10  is designed to maintain a predetermined distance G from the housing  4 .  
         [0009]     Here, the shroud  12 , the hub  14 , and the blades  16  are typically designed to have an identical outer diameter  10 D. For reference, the outer diameter of the blades  16  refers to a diameter of a circle which is defined by connecting distal ends of the plurality of blades  16 .  
         [0010]     In the mean time, the housing  4  is provided with a guide vane  30  to guide the air from the centrifugal impeller  10  to the discharge port  2  of the housing  4 .  
         [0011]     Operation of the conventional blowing device constructed as described above will be described as follows.  
         [0012]     When the motor  20  is driven, the centrifugal impeller  10  is rotated by rotational force of the motor  20 .  
         [0013]     Then, air outside the housing  4  is sucked into the centrifugal impeller  10  through the intake port  1  of the housing  4  and the inlet  12 ′ of the shroud  12 . The air sucked into the centrifugal impeller  10  is blown in the centrifugal direction of the centrifugal impeller  10  by the plurality of blades  16 , and is discharged from the centrifugal impeller  10 . The air discharged from the centrifugal impeller  10  is guided by the guide vane  30 , and is discharged from the housing  4  through the discharge port  2  of the housing  4 .  
         [0014]     As such, the centrifugal impeller  10  forcibly blows the air to generate blowing force.  
         [0015]     Meanwhile, the air discharged from the housing  4  can be introduced into the motor  20  for heat dissipation of the motor  20 .  
         [0016]     As such, since the conventional blowing device constructed as described above does not comprise a diffuser for distribution of air blown from the centrifugal impeller  10  to the guide vane  30 , and thus can be designed to have small dimensions, it is appropriate for small-sized electronic appliances such as cleaning apparatuses. However, the conventional blowing device has a problem in that absence of the diffuser causes the air discharged from the centrifugal impeller  10  not to smoothly flow to the guide vane  30 , and to leak to the intake port  1  of the housing  4  through a gap between the housing  4  and the shroud  12 , lowering fan efficiency.  
         [0017]     Additionally, the conventional blowing device has a problem in that, if the motor  20  is designed to dissipate heat using the air discharged from the housing  4 , the fan efficiency is lowered, causing insufficient heat dissipation of the motor  20 .  
         [0018]     Additionally, there is a problem in that air flow leaked from the intake port  1  of the housing  4  collides with air flow sucked through the intake port  1  of the housing  4 , causing severe flow noise.  
       SUMMARY OF THE INVENTION  
       [0019]     The present invention has been made to solve the above problems, and it is an object of the present invention to provide a blowing device which comprises a centrifugal impeller and a guide vane optimally designed to smoothly guide air from the centrifugal impeller to the guide vane, so that the blowing device can be reduced in dimensions and noise, while maximizing fan efficiency and heat dissipation of a motor.  
         [0020]     In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of a blowing device, comprising: a housing having an intake port and a discharge port, a shroud rotatably equipped within the housing and having an inlet communicated with the intake port of the housing, a hub separated from the shroud in an axial direction while being connected to the motor, and a plurality of impeller blades radially disposed between the hub and the shroud, wherein the impeller blades have an average diameter in the range of 87˜93% of a diameter of the housing.  
         [0021]     Each impeller blade may have a distal end perpendicular to the axial direction or slanted such that an outer diameter of the impeller blade is gradually decreased from the shroud to the hub.  
         [0022]     The shroud may have an outer diameter in the range of 103˜106% of the average diameter of the impeller blades.  
         [0023]     The hub may have an outer diameter in the range of 95˜98% of the average diameter of the impeller blades.  
         [0024]     An axial distance between a distal end of the shroud and a distal end of the hub may be in the range of 25˜50% of an axial height of the housing.  
         [0025]     The blowing device may further comprise: a guide vane including a guide vane plate opposite to the hub, and a plurality of guide vane blades radially disposed to the guide vane plate, wherein the guide vane blades have an outer diameter in the range of 103˜108% of the average diameter of the impeller blades.  
         [0026]     The guide vane plate may have an outer diameter in the range of 100˜102% of the average diameter of the impeller blades.  
         [0027]     The guide vane may have an axial height in the range of 100˜110% of the axial distance between the distal end of the shroud and the distal end of the hub.  
         [0028]     In accordance with another aspect of the present invention, a blowing device is provided, comprising: a housing having an intake port and a discharge port, a shroud rotatably equipped within the housing and having an inlet communicated with the intake port of the housing, a hub separated from the shroud in an axial direction while being connected to the motor, and a plurality of impeller blades radially disposed between the hub and the shroud, wherein the impeller blades have an average diameter in the range of 87˜93% of a diameter of the housing, the shroud has an outer diameter in the range of 103˜106% of the average diameter of the impeller blades, the hub has an outer diameter in the range of 95˜98% of the average diameter of the impeller blades, and an axial distance between a distal end of the shroud and a distal end of the hub is in the range of 25˜50% of an axial height of the housing.  
         [0029]     The blowing device may further comprise: a guide vane including a guide vane plate opposite to the hub, and a plurality of guide vane blades radially disposed to the guide vane plate, wherein the guide vane plate has an outer diameter in the range of 100˜102% of the average diameter of the impeller blades, the guide vane blades have an outer diameter in the range of 103˜108% of the average diameter of the impeller blades, and the guide vane has an axial height in the range of 100˜110% of the axial distance between the distal end of the shroud and the distal end of the hub.  
         [0030]     Each impeller blade may have a distal end perpendicular to the axial direction or slanted such that an outer diameter of the impeller blade is gradually decreased from the shroud to the hub.  
         [0031]     In accordance with yet another aspect of the present invention, a blowing device comprises: a housing having an intake port and a discharge port, a shroud rotatably equipped within the housing and having an inlet communicated with the intake port of the housing, a hub separated from the shroud in an axial direction while being connected to the motor, and a plurality of impeller blades radially disposed between the hub and the shroud, wherein the impeller blades have an average diameter smaller than a diameter of the shroud.  
         [0032]     Here, when outer diameters of the impeller blades refer to diameters of circles defined by connecting distal ends of the plurality of impeller blades, the average diameter of the impeller blades refers to an average of the outer diameters of the impeller blades in an axial direction.  
         [0033]     The hub may have a diameter smaller than the average diameter of the impeller blades.  
         [0034]     One of the advantages of the blowing apparatus constructed as described above is that the centrifugal impeller and the guide vane are optimally designed to allow air to smoothly flow from the centrifugal impeller to the guide vane without a diffuser, so that the blowing device can be reduced in dimensions and noise, while ensuring good fan efficiency and heat dissipation of a motor. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0035]     The foregoing and other objects and features of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:  
         [0036]      FIG. 1  is a perspective view illustrating a conventional blowing device;  
         [0037]      FIG. 2  is a cross-sectional view illustrating a main component of the conventional blowing device;  
         [0038]      FIG. 3  is a cross-sectional view illustrating a main component of a blowing device in accordance with a first embodiment of the present invention;  
         [0039]      FIG. 4  is a graph depicting fan efficiency according to variation in ratio of an average diameter of impeller blades to a diameter of a housing of the blowing device in accordance with the present invention;  
         [0040]      FIG. 5  is a graph depicting the fan efficiency according to variation in ratio of an outer diameter of a shroud to the diameter of the housing of the blowing device in accordance with the present invention;  
         [0041]      FIG. 6  is a graph depicting the fan efficiency according to variation in ratio of the outer diameter of the shroud to the average diameter of the impeller blades of the blowing device in accordance with the present invention;  
         [0042]      FIG. 7  is a graph depicting the fan efficiency according to variation in ratio of the outer diameter of the hub to the average diameter of the impeller blades of the blowing device in accordance with the present invention;  
         [0043]      FIG. 8  is a graph depicting the fan efficiency according to variation in ratio of an outer diameter of guide vane blades to the diameter of the housing of the blowing device in accordance with the present invention;  
         [0044]      FIG. 9  is a graph depicting the fan efficiency according to variation in ratio of the outer diameter of the guide vane blades to the average diameter of the impeller blades of the blowing device in accordance with the present invention;  
         [0045]      FIG. 10  is a graph depicting the fan efficiency according to variation in ratio of an outer diameter of a guide vane plate to the diameter of the housing of the blowing device in accordance with the present invention;  
         [0046]      FIG. 11  is a graph depicting the fan efficiency according to variation in ratio of the outer diameter of the guide vane plate to the average diameter of the impeller blades of the blowing device in accordance with the present invention;  
         [0047]      FIG. 12  is a graph depicting the fan efficiency according to variation in ratio of an axial height of the guide vane to an impeller height of a centrifugal impeller of the blowing device in accordance with the present invention;  
         [0048]      FIG. 13  is a graph depicting pressure coefficients of inventive and conventional blowing devices;  
         [0049]      FIG. 14  is a graph depicting the fan efficiency of the inventive and conventional blowing devices; and  
         [0050]      FIG. 15  is a cross-sectional view illustrating a blowing device in accordance with a second embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0051]     Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in which like reference numerals refer to like components throughout.  
         [0052]     It should be noted that although various embodiments can be realized within the scope of the invention, most preferred embodiments of the invention will be described hereinafter. Meanwhile, since the structure of a blowing device is the same as that of the conventional blowing device as described above, detailed description thereof will be omitted hereinafter.  
         [0053]      FIG. 3  is a cross-sectional view illustrating a main component of a blowing device according to a first embodiment of the invention.  
         [0054]     The blowing device according to the first embodiment of the invention comprises a housing  50  having an intake port  51  and a discharge port  42 , a centrifugal impeller  60  rotatably equipped within the housing  50  while being connected to a motor via a shaft  54  to generate blowing force from the intake port  51  to the discharge port  52  of the housing  50 , and a guide vane  70  equipped within the housing  50  to guide air blown by the centrifugal impeller  60  to the discharge port  52  of the housing  50 .  
         [0055]     The intake port  51  of the housing  50  is located at the center of a front side of the housing  50  so as to allow air to be sucked into the housing  50 . The outlet  52  of the housing  50  is located at a rear side of the housing  50 . Here, the rear side of the housing  50  can be entirely open.  
         [0056]     The housing  50  may be designed to have an axial height  50 H in the range of 20˜100% of a diameter  50 D of the housing  50 . Here, the diameter  50 D of the housing  50  refers to a diameter at a portion of the housing  50  where the centrifugal impeller  60  is located.  
         [0057]     The centrifugal impeller  60  comprises a shroud  62  having an inlet  62 ′ communicated with the intake port  51  of the housing  50 , a hub  64  separated from a rear side of the shroud  12  while being integrally coupled to the shaft  54  of the motor to rotate with the shaft  54 , and a plurality of impeller blades  66  radially disposed between the hub  64  and the shroud  62 .  
         [0058]     The shroud  62 , the hub  64 , and the impeller blades  66  are designed as follows in order to maximize fan efficiency and heat dissipation of the motor. For reference, since the size of the housing  50 , and an average diameter of the impeller blades  66  are references for designing the shroud  62 , the hub  64 , and the impeller blades  66 , the impeller blades  66  will be described first, and then the shroud  62  and the hub  64  will be described subsequently.  
         [0059]     The impeller blades  66  must be designed to maximize blowing capacity of the centrifugal impeller  60  while minimizing flow loss due to a narrow space between the housing  50  and the centrifugal impeller  60  under a predetermined condition of dimensions of the housing  50 . With regard to this,  FIG. 4  shows a graph depicting fan efficiency according to variation in ratio of an average diameter of the impeller blades  66  to the diameter  50 D of the housing  50 . As can be appreciated from  FIG. 4 , it is desirable that the impeller blades  66  have an average diameter in the range of 87˜93% of the diameter  50 D of the housing  50  in order to ensure an appropriate fan efficiency.  
         [0060]     Here, outer diameters of the impeller blades  66  refer to diameters of circles defined by connecting distal ends of the plurality of impeller blades  66 , and the average diameter  66 D of the impeller blades  66  refers to an average of the outer diameters of the impeller blades  66  in the axial direction. Here, the reason for using the average diameter  66 D of the impeller blades  66  is that, as the impeller blades  66  have the outer diameters gradually decreased from the shroud  62  to the hub  64 , the distal ends of the impeller blades  66  are slanted in the axial direction of the centrifugal impeller  60 .  
         [0061]     In addition, it is desirable that the average diameter  66   d  of the impeller blades  66  be smaller than a diameter  62 D of the shroud  62  in order to prevent air discharged from the centrifugal impeller  60  from being leaked to the intake port  51  of the housing  50  through a gap between the shroud  62  and the housing  50 .  
         [0062]     Next, it is desirable that the shroud  62  have not only the diameter  62 D larger than the average diameter  66 D of the impeller blades  66 , but also the following structure in consideration of interference with the housing  50 .  
         [0063]     With regard to this,  FIG. 5  shows a graph depicting the fan efficiency according to variation in ratio of an outer diameter  62 D of the shroud  62  to the diameter  50 D of the housing  50 . As can be appreciated from  FIG. 5 , it is desirable that the shroud  62  be designed to have an outer diameter  62 D greater than or equal to 90% of the diameter  50 D of the housing  50 . Additionally,  FIG. 6  shows a graph depicting the fan efficiency according to variation in ratio of the outer diameter  62 D of the shroud  62  to the average diameter of the impeller blades  66 . As can be appreciated from  FIG. 6 , it is desirable that the shroud  62  be designed to have the outer diameter  62 D greater than or equal to 103% of the average diameter of the impeller blades  66 .  
         [0064]     Additionally, in order to ensure that the ratio of the outer diameter  62 D of the shroud  62  to the average diameter of the impeller blades  66  is greater than or equal to a predetermined value under the predetermined condition of the size of the housing  50 , the ratio of the average diameter of the impeller blades  66  to the diameter  50 D of the housing  50  must be decreased. However, as described with reference to  FIG. 4 , the impeller blades  66  have the average diameter in the range of 87˜93% of the diameter  50 D of the housing  50 . Accordingly, it is desirable that the shroud  62  have the outer diameter  62 D in the range of 90˜95% of the diameter  50 D of the housing  50  while being in the range of 103˜106% of the average diameter  66 D of the impeller blades  66 .  
         [0065]     Next, it is desirable that the hub  64  be smaller than the impeller blades  66  in order to allow the air blown by the centrifugal impeller  60  to smoothly flow to the guide vane  70 . With regard to this,  FIG. 7  shows a graph depicting the fan efficiency according to variation in ratio of the outer diameter  64 D of the hub  64  to the average diameter of the impeller blades  66 . As can be appreciated from  FIG. 7 , it is desirable that the hub  64  have an outer diameter  64 D in the range of 95˜98% of the average diameter of the impeller blades  66 .  
         [0066]     With the structure as described above, the centrifugal impeller  60  has an impeller height  60 H in the range of 25˜50% of an axial height  50 H of the housing  50 . Here, the impeller height  60 H of the centrifugal impeller  60  refers to a distance defined by connecting a distal end of the hub  62  to a distal end of the hub  64  in the axial direction of the impeller  60 .  
         [0067]     The guide vane  70  comprises a plurality of guide vane blades  72  radially disposed at a rear side of the centrifugal impeller  60 , and a guide vane plate  74  opposite to the hub  64  to connect the plurality of guide vane blades  72 .  
         [0068]     The guide vane blades  72  and the guide vane plates  74  are also designed to optimize the fan efficiency and the heat dissipation of the motor, as described below.  
         [0069]      FIG. 8  shows a graph depicting the fan efficiency according to variation in ratio of an outer diameter  72 D of the guide vane blades  72  to the diameter  50 D of the housing  50 . The guide vane blades  72  are designed to have the outer diameter  72 D about 90% or 95% or more of the diameter  50 D of the housing  50 . Additionally,  FIG. 9  shows a graph depicting the fan efficiency according to variation in ratio of the outer diameter  72 D of the guide vane blades  72  to the average diameter of the impeller blades  66 . The guide vane blades  72  are designed to have the outer diameter  72 D less than 100% or 103% or more of the average diameter of the impeller blades  66 . Accordingly, in order to satisfy both conditions shown by the graphs of  FIGS. 8 and 9 , the guide vane blades  72  are designed to have the outer diameter  72 D in the range of 103˜108% of the average diameter of the impeller blades  66 .  
         [0070]     Here, the outer diameter  72 D of the guide vane blades  72  refers to a diameter of a circle defined by connecting distal ends of the guide vane blades  72 .  
         [0071]      FIG. 10  shows a graph depicting the fan efficiency according to variation in ratio of an outer diameter  74 D of the guide vane plate  74  to the diameter  50 D of the housing  50 . The guide vane plate  74  is designed to have the outer diameter  74 D about 90% of the diameter  50 D of the housing  50 . Additionally,  FIG. 11  shows a graph depicting the fan efficiency according to variation in ratio of the outer diameter  74 D of the guide vane plate  74  to the average diameter of the impeller blades  66 . The guide vane plate  74  is designed to have the outer diameter  74 D substantially the same as the average diameter of the impeller blades  66 . Accordingly, in order to satisfy both conditions shown by the graphs of  FIGS. 10 and 11 , the guide vane plate  74  is also designed to have the outer diameter  74 D in the range of 100˜102% of the average diameter of the impeller blades  66 .  
         [0072]     As shown in  FIG. 12 , an axial height  70 H of the guide vane  70  also influences the fan efficiency of the blowing device.  FIG. 12  shows a graph depicting the fan efficiency according to variation in ratio of the axial height  70 H of the guide vane  70  to the impeller height  60 H of the centrifugal impeller  60 . The guide vane  70  is designed to have the axial height  70 H in the range of 100˜110% of the impeller height  60 H of the centrifugal impeller  60 .  
         [0073]     Operation of the blowing device constructed as described above will be described as follows.  
         [0074]     When the motor is driven, the shroud  62 , the hub  64 , and the impeller blades  66  are integrally rotated to generate blowing force. Then, air outside the housing  50  is sucked into the centrifugal impeller  60  through the intake port  51  of the housing  50 , and the inlet  62 ′ of the shroud  62 . The air sucked into the centrifugal impeller  60  is discharged from the centrifugal impeller  60  in the centrifugal direction. The air discharged from the centrifugal impeller  60  is guided by the guide vane  30 , and is then discharged from the housing  50  to the outside through the discharge port  52  of the housing  50 .  
         [0075]     As shown in FIGS.  3  to  12 , the blowing device of the invention constructed as described above has the optimally designed centrifugal impeller  60  and guide vane  70 , so that the fan efficiency of the invention is enhanced in comparison to the conventional blowing device shown in  FIGS. 1 and 2 .  
         [0076]     With regard to this,  FIG. 13  shows a graph depicting relationship between pressure coefficient and flow coefficient of an inventive blowing device A and a conventional blowing device B, and  FIG. 14  shows a graph depicting relationship between the fan efficiency and the flow coefficient of the blowing devices A and B. As can be appreciated from  FIGS. 13 and 14 , the inventive blowing device A is excellent in pressure efficiency and fan efficiency to the conventional blowing device B.  
         [0077]     Additionally, when air discharged from the housing  50  flows into the motor in order to dissipate heat from the motor, the blowing device of the invention having the enhanced blowing force in comparison to the conventional blowing device can enhance the heat dissipation of the motor.  
         [0078]     Another embodiment of the invention will be described with reference to  FIGS. 13 and 14 , in which like elements will be denoted by like reference numerals, and detailed description thereof will be omitted.  
         [0079]      FIG. 15  is a cross-sectional view illustrating a blowing device according to a second embodiment of the invention.  
         [0080]     As shown in  FIG. 15 , in the blowing device according to the second embodiment, a centrifugal impeller  60  comprises a shroud  62 , a hub  64 , and a plurality of impeller blades  66 , which are optimally designed to ensure fan efficiency and heat dissipation of a motor.  
         [0081]     In particular, the impeller blades  66  are designed to have an average diameter in the range of 87˜93% of a diameter  50 D of the housing  50 , and to have distal ends perpendicular to the axial direction of the centrifugal impeller  60 .  
         [0082]     Here, since the impeller blades  66  have the distal ends perpendicular to the axial direction of the centrifugal impeller  60 , the impeller blades  66  have an identical outer diameter  66 D in the axial direction, and thus the average diameter of the impeller blades  66  is the outer diameter of the impeller blades  66 .  
         [0083]     As with the blowing device according to the first embodiment of the invention described with reference to FIGS.  3  to  14 , the blowing device according to the second embodiment of the invention constructed as described above can maximize the fan efficiency and heat dissipation of the motor.  
         [0084]     It should be understood that the embodiments and the accompanying drawings have been described for illustrative purposes and the present invention is limited by the following claims. Further, those skilled in the art will appreciate that various modifications, additions and substitutions are allowed without departing from the scope and spirit of the invention as set forth in the accompanying claims.