A flanged pulley to drive or be driven by a flat belt

Only the input is driven; every other part of this model moves by physics (MuJoCo), and its ratios are measured. Run it live, change its parameters, or switch the friction off to see the output stop.

Modelled as

Front view, shafts level, gravity on. Two flanged pulleys, the flanges 1 cm above the rim and 4 cm apart. The smaller (radius 6 cm) is on the driving shaft, turned at 40 rpm (the one driven joint). The larger (radius 9 cm), 32 cm away, carries a load (a damper). A tensioned flat belt of links on real contact runs between the flanges of both and drives the larger by friction.

Measured

The large pulley turns at 0.6645 of the small one's speed against 0.6739 from the pitch radii, r + 0.2 (slip 1.4%), over 1 to 5.5 s. The belt stays on (radial deviation 0.26 cm, lateral 0). The deepest contact is 1.6 mm, inside the belt's soft contact.

Notes

Brown gives no sizes. The flanges keep the belt from running off sideways.

Film (MP4) · Still (PNG) · Spec (YAML) · Model (MJCF)