Rectilinear motion of slide produced by the rotation of screw

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

A lead-screw lies along x in two bearings and turns on its axis (16 rpm, the only driven joint): a right-hand thread of pitch 1.6 cm, 7.5 turns, a ridge 0.9 cm wide at the core and 0.3 at its tip, laid in 24 convex segments a turn. The slide carries a half-nut (drawn cut away at the front) whose 3-turn thread fills the screw groove with 0.04 cm clear each flank; the slide can only run along its rail. Each turn of the screw runs the slide one pitch, 1.6 cm. A weak spring (5 N/m, standing for the cut) keeps the same flanks loaded.

Measured

Slide speed against the screw: -0.0025 m/rad in both windows (ideal -0.002546 = the pitch over 2 pi, sign from the hand of the thread and the turn), r2 1.0000; travel 0.18..3.93 cm; max penetration 0.06 mm.

Notes

Only the threads touch; the lead is not imposed, it comes from flank contact.

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