Air sending device, air-conditioning apparatus, and refrigeration cycle device

Abstract

An air sending device is provided with a cross flow fan including an impeller in which a plurality of blades is arranged annularly. Each of the blades includes a pressure surface, a suction surface, an inner peripheral end face, and an outer peripheral end face. The pressure surface of the blade satisfies the following relationship: a curvature of a second pressure-surface side curved surface>a curvature of a third pressure-surface side curved surface>a curvature of a first pressure-surface side curved surface. When a first, a second, and a third pressure-surface side area of a surface of part of a pressure surface side of the blade are projected on a chord line connecting the inner and outer peripheral end of the blade, a length of the third pressure-surface side area>a length of the first pressure-surface side area>a length of the second pressure-surface side area.

1 . An air sending device provided with a cross flow fan including an impeller in which a plurality of blades are arranged annularly,
 wherein each of the blades includes a pressure surface, a suction surface, an inner peripheral end face, and an outer peripheral end face, and in a section perpendicular to a rotation shaft of the cross flow fan, the pressure surface is concave in a rotation direction of the cross flow fan, the suction surface is convex in the opposite direction to the rotation direction, the inner peripheral end face is arcuately formed on an inner peripheral side of the blade and connecting the pressure surface and the suction surface, and the outer peripheral end face is arcuately formed on an outer peripheral side of the blade and connecting the pressure surface and the suction surface,   the outer peripheral end face is located more forwardly than the inner peripheral end face in the rotation direction,   the pressure surface of the blade includes a first pressure-surface side curved surface, a second pressure-surface side curved surface, and a third pressure-surface side curved surface that are arranged in this order from the inner peripheral side of the impeller, and the first pressure-surface side curved surface, the second pressure-surface side curved surface, and the third pressure-surface side curved surface have different curvatures that satisfy the following relationship: the curvature of the second pressure-surface side curved surface>the curvature of the third pressure-surface side curved surface>the curvature of the first pressure-surface side curved surface, and   where of two parts of the blade into which the blade is divided with respect to an imaginary center plane extending through a center portion of the blade that is located at the center of the blade in a thickness direction of the blade, a surface of part of the blade that is located on a pressure surface side of the blade is divided into three areas at an inner peripheral end and an outer peripheral end of the second pressure-surface side curved surface, the three areas being provided as a first pressure-surface side area, a second pressure-surface side area, and a third pressure-surface side area that are arranged in this order from the inner peripheral side,   when the first pressure-surface side area, the second pressure-surface side area, and the third pressure-surface side area are projected on a chord line connecting the inner peripheral end and the outer peripheral end of the blade, a length of the first pressure-surface side area, a length of the second pressure-surface side area, and a length of the third pressure-surface side area satisfy the following relationship: the length of the third pressure-surface side area>the length of the first pressure-surface side area>the length of the second pressure-surface side area.   
     
     
         2 . The air sending device of  claim 1 , wherein
 the suction surface of the blade includes a first suction-surface side curved surface, a second suction-surface side curved surface, and a third suction-surface side curved surface that are arranged in this order from the inner peripheral side of the impeller, and the first suction-surface side curved surface, the second suction-surface side curved surface, and the third suction-surface side curved surface have different curvatures in which the curvature of the first suction-surface side curved surface is smaller than the curvatures of the second suction-surface side curved surface and the third suction-surface side curved surface, and   where of two parts of the blade into which the blade is divided with respect to the imaginary center plane, a surface of part of the blade that is located on a suction surface side of the blade is divided into three areas at an inner peripheral end and an outer peripheral end of the second suction-surface side curved surface, an innermost circumferential area of the three areas being provided as a first suction-surface side area, when a length of the first suction-surface side area that is projected on the chord line is defined as a length of the first suction-surface side area,   the length of the first pressure-surface side area is greater than the length of the first suction-surface side area, and a position at which an outer peripheral end of the first pressure-surface side curved surface is projected on the chord line is located on the inner peripheral side relative to a center of the chord line.   
     
     
         3 . The air sending device of  claim 2 , wherein
 the suction surface of the blade is formed satisfying the following relationship: the curvature of the second suction-surface side curved surface>the curvature of the third suction-surface side curved surface>the curvature of the first suction-surface side curved surface, and   where the surface of part of the blade that is located on the suction surface side of the blade is divided into three areas at an inner peripheral end and an outer peripheral end of the second suction-surface side curved surface, the three areas being provided as the first suction-surface side area, a second suction-surface side area, and a third suction-surface side area that are arranged in this order from the inner peripheral side, when the first suction-surface side area, the second suction-surface side area, and the third suction-surface side area are projected on the chord line, a length of the first suction-surface side area, a length of the second suction-surface side area, and a length of the third suction-surface side area satisfy the following relationship: the length of the third suction-surface side area>the length of the second suction-surface side area>the length of the first suction-surface side area.   
     
     
         4 . The air sending device of  claim 1 , wherein when a position on the pressure surface, at which a perpendicular distance from the pressure surface to the chord line is maximized, is projected on the chord line, while an other position on the suction surface, at which a perpendicular distance from the suction surface to the chord line is maximized, is projected on the chord line, the position projected on the chord line is located on an outer peripheral side relative to the other position projected on the chord line. 
     
     
         5 . The air sending device of  claim 1 , wherein at a position at which the blade has a maximum blade thickness, when a center of the maximum blade thickness is projected on the chord line, a position of the center projected on the chord line is located within an area in which the first pressure-surface side curved surface is projected on the chord line, while being located within an area between a position equivalent to 10% of the chord line and a position equivalent to 15% of the chord line from the inner peripheral end of the blade. 
     
     
         6 . An air-conditioning apparatus comprising: the air sending device of  claim 1 ; a housing configured to accommodate the air sending device therein; and a heat exchanger. 
     
     
         7 . A refrigeration cycle device comprising the air sending device of  claim 1 .