Abstract: A propeller fan includes a hub 1 and a plurality of blades 2, which are radially arranged on the outer circumference of the hub 1. A plurality of bent surface-shaped recesses 21 to 23 are formed on the positive pressure surface at a trailing edge 2b of each blade 2. The recesses 21 to 23 extend in the rotation direction of the fan and are arranged in a radial direction. Protrusions 24, 25 are each formed between adjacent pair of the recesses 21 to 23. The bent surfaces of the recesses 21 to 23 and the protrusions 24, 25 reduces air flow caused by centrifugal force. This allows the air flow on the positive pressure surface of the blade 2 to easily flow along the recesses 21 to 23. As a result, air flow does not concentrate on the outer periphery of the blade 2, which reduces the differences in the velocity and volume of air flow between the outer tip 2c of the blade 2 and the hub 1. Accordingly, the blade 2 functions as a whole.

Abstract: An air delivery unit includes a casing, an air delivery device arranged in a fan passage in the casing, and a fan guard that is arranged at an air outlet of the casing and has an air blowing surface having a grill structure and a hollow frame wall portion. An air blowing opening is formed in the frame wall portion of the fan guard. This structure allows the air to be blown also from the opening of the frame wall portion of the fan guard. This reduces the amount and the speed of the air blown from the air blowing surface of the fan guard having the grill structure. As a result, rise of static pressure of the air delivery device is suppressed and noise caused by interference between bars of an air blowing grill and the air is reduced.

Abstract: A propeller fan includes a hub 1 and a plurality of blades 2, which are radially arranged on the outer circumference of the hub 1. A plurality of bent surface-shaped recesses 21 to 23 are formed on the positive pressure surface at a trailing edge 2b of each blade 2. The recesses 21 to 23 extend in the rotation direction of the fan and are arranged in a radial direction. Protrusions 24, 25 are each formed between adjacent pair of the recesses 21 to 23. The bent surfaces of the recesses 21 to 23 and the protrusions 24, 25 reduces air flow caused by centrifugal force. This allows the air flow on the positive pressure surface of the blade 2 to easily flow along the recesses 21 to 23. As a result, air flow does not concentrate on the outer periphery of the blade 2, which reduces the differences in the velocity and volume of air flow between the outer tip 2c of the blade 2 and the hub 1. Accordingly, the blade 2 functions as a whole.