Patent ID: 7044712

Claim:
An axial-flow fan comprising: a central hub connected with a driving shaft of a motor; and a plurality of blades extending radially along the circumference of the hub for blowing air toward an axial direction, the plurality of blades integrated with the hub into a single body, wherein assuming that a camber ratio at a blade root(cr 1 ) of each blade is the value obtained by dividing a maximum camber value at the blade root(cr 1 ) by a chord length, a camber ratio at a blade tip(cr 2 ) of each blade is the value obtained by dividing a maximum camber value at the blade tip by the chord length, and a percentage of decrease of the camber ratio is the value obtained by dividing a difference value between the camber ratio at the blade root(cr 1 ) and the camber ratio at the blade tip(cr 2 ) by the camber ratio at the blade root(cr 1 ), the percentage of decrease of the camber ratio is in a range between 33% and 85%, said camber ratio decreasing substantially proportionally along a length of each blade from said blade root toward said blade tip.