Air blowing apparatus and vacuum cleaner

Abstract

An air blowing apparatus according to an embodiment of the disclosure includes: a motor including a shaft extending vertically along a central axis; an impeller fixed to the shaft; and an impeller cover surrounding an upper and an outer side in a radial direction of the impeller and including a suction inlet at a center. The impeller includes multiple movable vanes, a lower shroud, and an upper shroud including a first raised portion and a second raised portion. A clearance in the axial direction between a lower surface of the impeller cover and at least one of the first and the second raised portion is smaller than a clearance in the axial direction between the lower surface of the impeller cover and the upper shroud on the inner side in the radial direction of the first raised portion.

What is claimed is: 
     
         1 . An air blowing apparatus comprising:
 a motor which includes a shaft disposed along a central axis extending vertically;   an impeller which is fixed to the shaft; and   an impeller cover which surrounds an upper side and an outer side in a radial direction of the impeller and which includes a suction inlet at a center, wherein   the impeller includes
 a plurality of movable vanes which are disposed in a circumferential direction, 
 a lower shroud which is disposed on the lower side of the movable vanes, 
 an upper shroud which is disposed on the upper side of the movable vanes and which includes a through hole penetrating in an axial direction, 
   the upper shroud includes
 a first raised portion which protrudes upward from an upper surface of the upper shroud and which extends in the circumferential direction, 
 a second raised portion which is disposed on the outer side in the radial direction of the first raised portion, which protrudes upward from the upper surface of the upper shroud, and which extends in the circumferential direction, and 
   a clearance in the axial direction between a lower surface of the impeller cover and at least one of the first raised portion and the second raised portion is smaller than a clearance in the axial direction between the lower surface of the impeller cover and the upper shroud on the inner side in the radial direction of the first raised portion.   
     
     
         2 . The air blowing apparatus according to  claim 1 , wherein
 the second raised portion is disposed on an outer edge in the radial direction of the upper shroud.   
     
     
         3 . The air blowing apparatus according to  claim 1 , wherein
 an upper end of the first raised portion is disposed higher than an upper end of the second raised portion.   
     
     
         4 . The air blowing apparatus according to  claim 1 , wherein
 the upper shroud includes a plurality of upper shroud wall portions which are disposed in the circumferential direction and which connect the first raised portion and the second raised portion together.   
     
     
         5 . The air blowing apparatus according to  claim 4 , wherein
 an inner end in the radial direction of each of the upper shroud wall portions is disposed in front of a corresponding outer end in the radial direction of the upper shroud wall portion in a rotational direction of the impeller.   
     
     
         6 . The air blowing apparatus according to  claim 4 , wherein
 a height in the axial direction of an upper end of each of the upper shroud wall portions is equal to a height in the axial direction of the upper end of the first raised portion.   
     
     
         7 . The air blowing apparatus according to  claim 4 , wherein
 the number of the upper shroud wall portions and the number of the movable vanes are different from each other.   
     
     
         8 . The air blowing apparatus according to  claim 4 , wherein
 at least one of the upper shroud wall portions is disposed between the adjacent movable vanes in the circumferential direction.   
     
     
         9 . The air blowing apparatus according to  claim 4 , wherein
 the upper shroud includes a plurality of upper side balance correcting portions which are formed by the first raised portion, the second raised portion, and the plurality of upper shroud wall portions, and   a shape of each of the upper side balance correcting portions is asymmetric with respect to the central axis.   
     
     
         10 . The air blowing apparatus according to  claim 4 , wherein
 the upper shroud includes a plurality of upper side balance correcting portions which are formed by the first raised portion, the second raised portion, and the plurality of upper shroud wall portions, and   at least one of the upper side balance correcting portions is provided with a weight.   
     
     
         11 . The air blowing apparatus according to  claim 8 , wherein
 a lower side balance correcting portion is formed on the outer side in the radial direction of the motor.   
     
     
         12 . The air blowing apparatus according to  claim 11 , wherein
 the motor includes
 a rotor unit which includes a lidded cylindrical rotor holder fixed to the shaft and opened upward, 
 a stator unit which faces the rotor unit in the radial direction, and 
 a bearing which rotatably supports the shaft relative to the stator unit, and 
   the rotor holder includes the lower side balance correcting portion.   
     
     
         13 . A vacuum cleaner comprising the air blowing apparatus according to  claim 1 .