| 摘要 |
An impeller for a variable pitch axial flow fan in which the actuator is arranged to rotate the blades towards their maximum pitch angle, and the inherent blade turning moment of the blades when the impeller is rotating provides the restoring force for moving the blades towards their minimum pitch angle. The impeller avoids the need for blade counterweights and a heavy return spring, and so enables a relatively smaller and lighter hub to be used compared with those employed in equivalent impellers with counterweighted blades. |
