Blower and vacuum cleaner

Abstract

A blower includes an impeller rotatable about a central axis extending in a vertical direction, a motor on a lower side of the impeller that rotates the impeller about the central axis, and a duct including an airflow passage in an inner space, a suction port through which a fluid flows in the inner space, and an air outlet through which the fluid is discharged from the inner space, the impeller being accommodated in the duct. The impeller includes blades arranged in a circumferential direction, an annular shroud that connects upper portions of the blades and includes an opening opposing the suction port in an axial direction, and a base plate that connects lower portions of the blades and extends in a radial direction. The duct includes a cover covering at least a portion of the blade and an upper portion of the shroud. An inner diameter of the shroud is equal to or larger than an outer diameter of the base plate. The cover includes a projection that projects axially downward from a bottom surface of the cover and is on a radial interior of an inner circumferential surface of the shroud.

What is claimed is: 
     
         1 . A blower comprising:
 an impeller rotatable about a central axis extending in a vertical direction;   a motor that is positioned on a lower side of the impeller and rotates the impeller about the central axis; and   a duct including an airflow passage in an inner space, a suction port through which a fluid flows in the inner space, and an air outlet through which the fluid is discharged from the inner space, the impeller being accommodated in the duct; wherein   the impeller includes:
 a plurality of blades arranged in a circumferential direction; 
 a shroud that has an annular shape, connects upper portions of the plurality of blades, and includes an opening located opposite to the suction port in an axial direction; and 
 a base plate that connects lower portions of the plurality of blades and extends in a radial direction; wherein 
   the duct includes a cover covering at least a portion of the plurality of blades and an upper portion of the shroud;   an inner diameter of the shroud is equal to or larger than an outer diameter of the base plate; and   the cover includes a projection that projects axially downward from a bottom surface of the cover and is disposed on a radial interior of an inner circumferential surface of the shroud.   
     
     
         2 . The blower according to  claim 1 , wherein an outer circumferential surface of the projection is radially opposed to the inner circumferential surface of the shroud. 
     
     
         3 . The blower according to  claim 2 , wherein a lower side in the axial direction is wider than an upper side in the axial direction in a radial gap between the outer circumferential surface of the projection and the inner circumferential surface of the shroud. 
     
     
         4 . The blower according to  claim 1 , wherein each of the plurality of blades includes:
 a blade first region located on a radial exterior of the projection; and   a blade second region vertically opposed to the projection; and   an upper end of the blade first region is located above an upper end at a radially outer end of the blade second region.   
     
     
         5 . The blower according to  claim 1 , wherein the blade includes a protrusion that protrudes axially upward on a radial exterior of the projection. 
     
     
         6 . The blower according to  claim 1 , wherein a lower end of the inner circumferential surface of the shroud and a lower end of a radially outer end of the projection have an identical or substantially identical height in the axial direction. 
     
     
         7 . The blower according to  claim 1 , wherein a radially outer end of each of the plurality of blades extends to a radial exterior of an outer circumference of the base plate. 
     
     
         8 . The blower according to  claim 1 , wherein a radially inner end of each of the plurality of blades extends to a radial interior of the suction port. 
     
     
         9 . The blower according to  claim 1 , further comprising a motor housing located below the base plate, wherein
 the base plate includes a base plate protrusion protruding downward from a bottom surface of the base plate; and   an axial gap between a lower end of the base plate protrusion and a top surface of the motor housing is narrower than an axial gap between the bottom surface of the base plate and the top surface of the motor housing.   
     
     
         10 . The blower according to  claim 9 , wherein
 the base plate protrusion is located at a radially outer edge of the base plate; and   a groove is located on the top surface of the motor housing, is vertically opposed to the base plate protrusion, and has a radial width larger than a radial width of the base plate protrusion.   
     
     
         11 . A vacuum cleaner comprising the blower according to  claim 1 .