Air blower and cleaner

Abstract

An air blower includes a motor including a shaft, an impeller fixed to the shaft, and a motor housing disposed radially outwardly of the motor. The impeller includes an impeller base that extends radially outwardly at an axially lower position. The impeller base includes a boss section fixed to the shaft. The motor housing includes an upper surface cylindrical section that extends axially upward from a radially inner end of the motor housing upper surface. At least a portion of a radially inner surface of the upper surface cylindrical section is radially opposed to a radially outer surface of the shaft or the boss section, and an axially upper end of the upper surface cylindrical section is disposed over an axially lower end of the impeller base and over an upper end of a bearing.

What is claimed is: 
     
         1 . An air blower comprising:
 a motor including a shaft disposed along a central axis extending vertically;   an impeller that is disposed over the motor and fixed to the shaft; and   a motor housing that is disposed outwardly of the motor in a radial direction;   the motor including a bearing that supports the shaft rotatably with respect to the motor housing;   the impeller including:
 an impeller base that extends outwardly in the radial direction at a lower position in an axial direction; and 
 a plurality of blades disposed on an upper surface of the impeller base; 
   the impeller base including:
 a boss section fixed to the shaft; and 
 a lower surface recess on an outer side of the boss section in the radial direction, the lower surface recess being included in a lower surface of the impeller base and recessed upwardly in the axial direction; 
   the motor housing including:
 a motor housing upper surface that is disposed under the impeller base, and opposed to the lower surface of the impeller base in the axial direction; and 
 an upper surface cylindrical section in a cylindrical shape, the upper surface cylindrical section extending upward in the axial direction from an inner end of the motor housing upper surface in the radial direction; wherein 
   at least a portion of a radially inner surface of the upper surface cylindrical section is opposed to a radially outer surface of the shaft or the boss section in the radial direction; and   an upper end of the upper surface cylindrical section in the axial direction is disposed over a lower end of the impeller base in the axial direction and over an upper end of the bearing.   
     
     
         2 . The air blower according to  claim 1 , wherein the radially inner surface of the upper surface cylindrical section has a uniform radial distance from the radially outer surface of the shaft or the boss section over an entire area in the radial direction. 
     
     
         3 . The air blower according to  claim 1 , wherein the radially inner surface of the upper surface cylindrical section has a larger radial distance from the shaft or the boss section at an upper position in the axial direction. 
     
     
         4 . The air blower according to  claim 1 , wherein the radially inner surface of the upper surface cylindrical section includes:
 a first inner surface section that has a uniform radial distance from the radially outer surface of the shaft or the boss section over an entire area in the radial direction; and   a second inner surface section that is connected to an upper end of the first inner surface section in the axial direction, and has a larger radial distance from the shaft or the boss section at an upper position in the axial direction.   
     
     
         5 . The air blower according to  claim 1 , wherein the impeller base includes a lower surface projection in a cylindrical shape, the lower surface projection being disposed outwardly of the upper surface cylindrical section in the radial direction, and extending downward in the axial direction. 
     
     
         6 . The air blower according to  claim 5 , wherein a radially inner surface of the lower surface projection extends outwardly in the radial direction at a lower position in the axial direction. 
     
     
         7 . The air blower according to  claim 5 , wherein a radially outer surface of the lower surface projection extends outwardly in the radial direction at an upper position in the axial direction. 
     
     
         8 . The air blower according to  claim 5 , wherein an axially lower surface of the lower surface projection is connected to the lower surface of the impeller base and extends in a direction perpendicular to the central axis. 
     
     
         9 . The air blower according to  claim 1 , wherein
 the motor housing includes an inner surface projection that extends inwardly in the radial direction from a radially inner surface of the motor housing; and   an upper surface of the bearing in the axial direction is in contact with a lower surface of the inner surface projection in the axial direction.   
     
     
         10 . The air blower according to  claim 9 , wherein the upper surface cylindrical section extends upwardly in the axial direction from the inner surface projection. 
     
     
         11 . The air blower according to  claim 1 , wherein the upper surface of the bearing in the axial direction is disposed over the lower end of the impeller base in the axial direction. 
     
     
         12 . The air blower according to  claim 1 , wherein
 the motor housing further includes a bearing retainer in a cylindrical shape, which extends along the central axis;   a radially inner surface of the bearing retainer retains a radially outer surface of the bearing; and   the upper surface cylindrical section is connected to the bearing retainer.   
     
     
         13 . The air blower according to  claim 12 , wherein the bearing includes:
 an upper bearing; and   a lower bearing that is disposed under the upper bearing in the axial direction; and   the radially inner surface of the bearing retainer retains radially outer surfaces of the upper bearing and the lower bearing.   
     
     
         14 . A cleaner comprising the air blower according to  claim 1 .