| 摘要 |
An engine cooling system includes a ring-type cooling fan (10) that includes a central hub (12), a plurality of blades (11) projecting radially from the hub (12) and an outer circumferential ring (15) connected to the blade tips (17). In one aspect of the invention, the outer ring (15) includes a flared rim (28) at the outlet side (10b) of the fan (10) that improves the stackability and stability of multiple fans. In another aspect of the invention, each of the blades (11) includes a support vane (30) defined on the rear face (25) of the blade (11). The support vane (30) is curved to follow the curvature of the airflow (F) across the back (25) of the fan blades (11). Each support vane (30) originates at the blade root (19) and terminates at the trailing edge (11b) of the blade in the first half of the blade length. The support vanes (30) provide first mode stiffness for the fan (10). In certain embodiments, a support ring (35) is defined at the central hub (12) inboard of the support vanes (30). A vane support superstructure (37) is configured between the support vanes (30) and the support ring (35) to react the aerodynamic loads experienced by the support vanes (30). A further support superstructure (37) can be configured between the support ring (35) and the central hub (12). Other features of the invention provide a stress-reducing blend region (20) between the blade tips (17) and the flared rim (28) of the outer ring (15), and an improved blade geometry. |
