| 摘要 |
A fan wheel or pre-guide wheel for axial or semi-axial air flow, especially for use with the cooling systems of motor vehicles. In order to provide for advantageous stream line flow, the leading surfaces of the fan wheel hub or an upstream pre-guide wheel hub are suitably rounded providing for a generally increasing hub diameter in the direction of the air flow. In order to simplify the casting or extrusion of the fan wheel so configured, the invention provides for a substantially cylindrical or conically decreasing hub diameter in the region of the fan hub lying generally behind each fan blade. For fan hubs of relatively low axial depth, for example with riveted fan blades, the gaps may remain uncovered without detrimental effects on the air stream. In one-piece cast fan wheels or pre-guide wheels, including a central hub and a plurality of vanes mounted thereon, the gaps are suitably covered by, especially, lightweight, unstressed segments which may be part of a single segment ring attached by suitable means to the hub of the fan. |
