Composite material worm wheel - has swaged bronze wheel rim mounted on cast iron hub

摘要

To save expensive bronze when producing large diameter worm wheels, the wheel hub (1) is made from cast iron, whilst only the rim (2) is made from bronze. The wheel rim and the hub are then assembled by deforming the rim axially so that radial flanges are formed (14) on either side of the wheel hub (1). In order to improve the fit between rim and hub, the rim is heated to about 400 deg.C whilst the hub is shrunk by cooling. The assembly is done in a spring loaded locating nest (3-7) which ensures that the hub and rim are held in the correct relative axial position when the rim deforming clamping load is applied.