Propeller Fan and Air Conditioner Equipped with the Same

Abstract

In order to suppress that a velocity in the vicinity of a bell mouth is lowered to induce non-uniformity in velocity at an outlet of a blade and an outlet of the bell mouth caused by adoption of a forward-swept blade which makes a tip vortex small as means for noise reduction, in a blade of a propeller fan, a trailing edge portion which has been rotationally projected on a plane passing through a rotational axis is formed from the rotational axis toward a blade tip portion so as to bend from the suction side to the discharge side with a first curvature, and is further formed so as to bend with a second curvature which is smaller than the aforementioned first curvature with an inflection point interposed.

1 . A propeller fan, comprising:
 a rotational axis serving as a center of rotation; and   a plurality of blades provided around the rotational axis,   a bell mouth being arranged outside in an outer radial direction of the plurality of blades, wherein   each of the plurality of blades is formed by   a trailing edge portion formed on the rear relative to a rotation direction, a leading edge portion formed on the front relative to the rotation direction, a blade tip portion formed from a tip portion in an outer radial direction of the trailing edge portion toward a tip portion in an outer radial direction of the leading edge portion,   the trailing edge portion which has been rotationally projected on a plane passing through the rotational axis is formed from the rotational axis toward the blade tip portion so as to bend from the suction side to the discharge side with a first curvature, and further is formed so as to bend with a second curvature which is smaller than the first curvature with an inflection point interposed.   
     
     
         2 . The propeller fan according to  claim 1 , wherein
 on an end face of the bell mouth which is closest to the blade, a position which is an end portion in a discharge direction and where an angle is changed in an outer radial direction almost matches a position of the inflection point, viewing from above a rotation plane.   
     
     
         3 . The propeller fan according to  claim 1 , wherein
 the trailing edge portion which has been rotationally projected on a plane vertical to the rotational axis is formed to be convex in a reverse rotation direction from the rotational axis toward the blade tip portion, and is formed linearly or to be convex in the rotation direction with the inflection point interposed.   
     
     
         4 . The propeller fan according to  claim 1 , wherein
 each of the plurality of blades is,   a blade force acts on a part formed with the first curvature in the trailing edge portion so as to direct in an outer radial direction relative to a direction of the rotational axis and a blade force acts on a part formed with the second curvature in the trailing edge portion so as to direct in an inner radial direction relative to the direction of the rotational axis.   
     
     
         5 . The propeller fan according to  claim 1 , comprising:
 a guard which lets air pass toward the discharge side of the blade, prevents mixing of a foreign material which exceeds a predetermined size and is apart from the propeller with a distance exceeding a predetermined length.   
     
     
         6 . An air conditioner, comprising:
 a housing having a suction port and a discharge port of air;   a heat exchanger arranged in the housing; and   a fan which is arranged upstream or downstream of the heat exchanger and sucks air on the outside of the housing through the suction port and discharges the air through the discharge port, wherein   the propeller fan according to  claim 1  has been used as the fan.