Bell-mouth structure of air blower

Abstract

A bell-mouth structure of an air blower provided around a blade wheel of an axial-flow air blower for guiding air from an air suction side of the blade wheel to an air blow-out side including an air blow-out wall portion that intercommunicates with an air blow-out opening and extends substantially along an axial direction of the blade wheel, and a slope wall portion that intercommunicates with the air blow-out wall portion and slopes to an air suction opening so as to expand in diameter. When the overall height of the bell-mouth is represented by H, the height of the slope wall portion is represented by h and a slope angle of the slope wall portion is represented by β, the bell mouth structure is configured so as to satisfy 0.33≦h/H≦0.42 and 60°≦β≦70°.

1 . A bell-mouth structure of an air blower that is provided around a blade wheel of an axial-flow air blower and guides air from an air suction side of the blade wheel to an air blow-out side of the blade wheel, comprising:
 an air blow-out wall portion that intercommunicates with an air blow-out opening and extends substantially along an axial direction of the blade wheel; and   a slope wall portion that intercommunicates with the air blow-out wall portion and slopes to an air suction opening so as to expand in diameter, wherein when the overall height of the bell-mouth is represented by H, the height of the slope wall portion is represented by h and a slope angle of the slope wall portion is represented by β, the bell mouth structure is configured so as to satisfy 0.33≦h/H≦0.42 and 60°≦β≦70°.   
     
     
         2 . The bell mouth structure according to  claim 1 , wherein when the diameter of an opening of a connecting portion between the air blow-out wall portion and the slope wall portion is represented by D and the diameter of the blade wheel is represented by d, 1.02<D/d<1.03 is satisfied. 
     
     
         3 . The bell mouth structure according to  claim 1 , wherein when the height from the air suction opening to the position of a blade out of blades of the blade wheel which is nearest to the air suction opening is represented by hL, 0.24≦hL/h≦0.4 is satisfied. 
     
     
         4 . The bell mouth structure according to  claim 1 , wherein when the height from the air suction opening to a position of a blade out of blades of the blade wheel which is nearest to the air blow-out opening is represented by hZ, 0.875≦hZ/H≦0.925 is satisfied. 
     
     
         5 . The bell mouth structure according to  claim 1 , wherein the axial-flow air blower is a propeller fan. 
     
     
         6 . The bell mouth structure according to  claim 5 , wherein the blade wheel of the propeller fan is disposed so as to be perfectly overlapped with the bell mouth in side view. 
     
     
         7 . An air conditioner comprising:
 a heat exchanger;   an axial-flow air blower having a blade wheel for blowing air to the heat exchanger; and   a bell mouth that is provided around the blade wheel of the air blower and guides air from an air suction side of the blade wheel to an air blow-out side, wherein the bell mouth has an air blow-out wall portion that intercommunicates with an air blow-out opening and extends substantially along an axial direction of the blade wheel, and a slope wall portion that intercommunicates with the air blow-out wall portion and slopes to an air suction opening so as to expand in diameter, and when the overall height of the bell-mouth is represented by H, the height of the slope wall portion is represented by h and a slope angle of the slope wall portion is represented by β, the bell mouth is configured so as to satisfy 0.33≦h/H≦0.42 and 60°≦β≦70°.