| 摘要 |
A radial type cooling fan for an electric motor (1, 3) has an impeller (4) with a plurality of stiff fan blades (41, 45) arranged on the impeller. Each blade is rotatably arranged around a turning axis (B-B, C-C) substantially parallel to the rotary axis (A-A) of the fan. The blades are arranged in such a way that the centrifugal force on the blade, caused by the rotation of the fan, strives to turn the blade around the turning axis in such a way that the angle of incidence of the blade is reduced. Further, the fan has spring members which are adapted to exert on the blade a torque which counteracts the turning of the blade caused by the centrifugal force. The blades are arranged such that the radially inner edge of each blade is positioned before the outer edge of the same blade in the direction of rotation. |
