| 摘要 |
A fan, for a ventilation assembly has blades extending from a cup-shaped central hub. The hub has an annular side wall and a bottom wall defining a receptacle for an electric motor. The hub has internal ribs for ventilation of the motor. Each rib has a longitudinal portion which extends along the side wall, a radial portion which extends along the bottom wall and an intermediate portion having an arcuate, transversely protruding profile. The longitudinal portion has a profile whose spacing from the side wall of the hub increases, from a minimum value remote from the bottom wall to a maximum value adjacent the bottom wall. |
