| 摘要 |
<p>A machine element such as a fan impeller is made by moulding or casting the blade ring wheel of plastic material or soft metal on a metallic tubular hub. The hub is made of a metal tube section which is deformed by radial forces to a polygonal shape and by axial forces to form a peripheral bulge in the centre. The blade ring wheel is joined to this bulge. The cold forming of the hub results in work hardening and improves its strength. The new method produces a reliable connection of hub and wheel at low cost.</p> |
