Impeller and blowing apparatus including the same

Abstract

An impeller includes a body portion having a tubular shape and a plurality of blade portions. The body portion is rotatable about a center axis. The plurality of blade portions protrude in a radial direction from an outer circumferential surface of the body portion and are arranged at intervals in a circumferential direction. When the blade portions rotate about the center axis, the impeller blows air in an axial direction. Each of the blade portions extends in the circumferential direction while being inclined to an upstream side in an air blowing direction toward a front side in a rotation direction. Each of the blade portions is curved to be convex toward a downstream side in the air blowing direction at the front side in the rotation direction with respect to a center in the circumferential direction.

What is claimed is: 
     
         1 . An impeller, comprising:
 a body portion having a tubular shape and being rotatable about a center axis; and   a plurality of blade portions protruding in a radial direction from an outer circumferential surface of the body portion and arranged at intervals in a circumferential direction; wherein   when the plurality of blade portions rotate about the center axis, the impeller blows air in an axial direction; and   each of the plurality of blade portions extends in the circumferential direction while being inclined to an upstream side in an air blowing direction toward a front side in a rotation direction, and each of the plurality of blade portions is curved to be convex toward a downstream side in the air blowing direction at the front side in the rotation direction with respect to a center in the circumferential direction.   
     
     
         2 . The impeller according to  claim 1 , wherein each of the plurality of blade portions is curved to be convex toward the upstream side in the air blowing direction at a rear side in the rotation direction with respect to the center in the circumferential direction. 
     
     
         3 . The impeller according to  claim 1 , wherein the outer circumferential surface of the body portion extends parallel or substantially parallel to the center axis on the upstream side in the air blowing direction with respect to an end at the front side in the rotation direction of each of the plurality of blade portions. 
     
     
         4 . The impeller according to  claim 1 , wherein an outer diameter of the body portion decreases toward the downstream side in the air blowing direction on the downstream side in the air blowing direction with respect to an end at the rear side in the rotation direction of each of the plurality of blade portions. 
     
     
         5 . The impeller according to  claim 1 , wherein a width of each of the plurality of blade portions in the radial direction at an end portion at the front side in the rotation direction is smaller than a width of each of the plurality of blade portions in the radial direction at an end portion at the rear side in the rotation direction. 
     
     
         6 . The impeller according to  claim 1 , wherein, in adjacent ones of the plurality of blade portions in the circumferential direction, an end portion of one of the blade portions at the front side in the rotation direction and an end portion of the other of the blade portions at the rear side in the rotation direction overlap each other when viewed from the axial direction. 
     
     
         7 . A blowing apparatus, comprising:
 the impeller according to  claim 1 ; and   a motor to rotate the impeller.   
     
     
         8 . A blowing apparatus, comprising:
 the impeller according to  claim 1 ;   an upstream impeller upstream of the impeller in an air blowing direction and aligned coaxially or substantially coaxially with the impeller; and   a motor to rotate each of the impeller and the upstream impeller.