Impeller, air-sending apparatus, and cleaning machine

Abstract

An impeller includes a main plate spreading radially with respect to the center axis, a plurality of blades provided on an upper surface of the main plate and arranged side by side in a circumferential direction, a shroud connected to tops of the plurality of blades and having an intake port that is an opening extending upward, and a mount portion provided on the upper surface of the main plate and positioned on an inner side with respect to a radially outer end of the main plate. The mount portion has a plurality of recesses each being depressed downward from an upper surface of the mount portion and extending in a direction away from the center axis.

What is claimed is: 
     
         1 . An impeller that rotates on a center axis extending in a vertical direction, the impeller comprising:
 a main plate spreading radially with respect to the center axis;   a plurality of blades provided on an upper surface of the main plate and arranged side by side in a circumferential direction;   a shroud connected to tops of the plurality of blades and having an intake port that is an opening extending upward; and   a mount portion provided on the upper surface of the main plate and positioned on an inner side with respect to a radially outer end of the main plate,   wherein the mount portion has a plurality of recesses each being depressed downward from an upper surface of the mount portion and extending in a direction away from the center axis.   
     
     
         2 . The impeller according to  claim 1 ,
 wherein a radially inner end of each of the recesses is positioned on a forward side in a direction of rotation of the impeller with respect to a radially outer end of the recess.   
     
     
         3 . The impeller according to  claim 1 ,
 wherein a side surface of each of the recesses that is on the forward side in the direction of rotation includes a recess-widening part extending upward while inclining toward the forward side in the direction of rotation such that the recess is widened.   
     
     
         4 . The impeller according to  claim 1 ,
 wherein a side surface of each of the recesses that is on a backward side in the direction of rotation extends parallel to the center axis.   
     
     
         5 . The impeller according to  claim 1 ,
 wherein a distance from the center axis to a radially outer end of the mount portion is smaller than a distance from the center axis to a radially inner end of each of the blades.   
     
     
         6 . The impeller according to  claim 1 ,
 wherein the distance from the center axis to the radially outer end of the mount portion is smaller than a distance from the center axis to a radially outer end of the intake port.   
     
     
         7 . The impeller according to  claim 1 ,
 wherein a height of the mount portion at the radially outer end of the mount portion is smaller than a height of each of the blades on a radially inner side of the blade.   
     
     
         8 . The impeller according to  claim 1 ,
 wherein the mount portion includes
 the plurality of recesses arranged side by side in the circumferential direction; and 
 hills each provided between circumferentially adjacent ones of the recesses and projecting upward with respect to the recesses, and 
   wherein a circumferential length of each of the recesses at the radially outer end of the recess is smaller than a circumferential length of each of the hills at a radially outer end of the hill.   
     
     
         9 . The impeller according to  claim 1 ,
 wherein a circumferential opening angle of each of the recesses at the radially outer end of the recess with respect to the center axis is smaller than a circumferential angle formed between the radially inner ends of circumferentially adjacent ones of the blades with respect to the center axis.   
     
     
         10 . The impeller according to  claim 1 ,
 wherein a bottom surface of each of the recesses at the radially outer end of the recess is positioned above the upper surface of the main plate.   
     
     
         11 . The impeller according to  claim 1 ,
 wherein the mount portion includes an inclined part whose upper surface descends toward the radially outer side of the mount portion.   
     
     
         12 . The impeller according to  claim 1 ,
 wherein, letting a number of recesses be N1 and a number of blades be N2, a value expressed by N1/N2 falls within a range from 0.5 to 1.2.   
     
     
         13 . The impeller according to  claim 1 ,
 wherein the main plate is fixed to a shaft with a fixing member, the shaft being rotatable on the center axis,   wherein the mount portion is provided separately from the main plate,   wherein a lower surface of the mount portion is in contact with the upper surface of the main plate, and   wherein the upper surface of the mount portion is in contact with a lower surface of the fixing member.   
     
     
         14 . The impeller according to  claim 1 ,
 wherein the mount portion is a part of the main plate.   
     
     
         15 . An air-sending apparatus comprising:
 the impeller according to  claim 1 .   
     
     
         16 . A cleaning machine comprising:
 the air-sending apparatus according to  claim 15 .