Patent attributes
Whereas for each propeller blade of a radiator fan, an attachment angle θ1 at a propeller blade base portion, projected onto a plane parallel to an attachment surface of the propeller blades with respect to the boss is set in a range of 35 to 45°, an attachment angle θ2 of a propeller blade tip portion is set in a range of 15 to 22°. Seven propeller blades and a chord length Ct of the propeller blade tip portion, and an outer circumference length π×Df of the propeller blades are set to satisfy a relationship 0.65<7Ct/(π×Df)<0.85. A tip broadening ratio of the propeller blades is set to within a range Ct/Cb=1.5 to 2.1, based on the chord length Ct at the propeller blade tip portion, and a chord length Cb at the propeller blade base portion. A fan sweep angle θ3 is set in a range of 15 to 25°.
