4 : 1 · slim wrist, one-sided carrier

A short 4 : 1 with a single-sided carrier and four planets, for a robot wrist.

Robot joints & actuators4 : 14 planetsRing held

Build it with your AI

Using the CheapCADTools connector, design a 4 : 1 planetary gear set in Planetary Gear Designer: module 1 mm, 20° pressure angle, spur teeth, a 21-tooth sun, 21-tooth planets and a 63-tooth ring, four planets, a profile shift of 0.2 on the planets, face width 8 mm. The sun: a 5 mm bore with a D-flat 0.5 mm deep. The carrier: a one-sided (cantilevered) carrier. The carrier's output: a 5 mm bore. Set an input torque of 0.45 N·m. Check the design, apply any Auto-fix it suggests, then export every part (the sun, a planet, the ring and the carrier) as STEP and STL and give me the download link.

Paste it into Claude, ChatGPT or any AI app with the CheapCADTools connector, and it designs this planetary set with you, checks it and hands you the files. How to connect your AI.

What's in this design

Sun

21 teeth · no shift · tip Ø22.99 mm · face 8 mm · bore Ø5 mm D-flat (0.5 mm flat) · no hub

Planets · 4

21 teeth · shift +0.2 · tip Ø23.39 mm · face 8 mm · bore Ø5.3 mm on a Ø5 mm pin · print 4

Ring

63 internal teeth · shift −0.4 · outside Ø76.57 mm · rim 5 mm below the roots

Carrier

cantilevered (one disc) · disc Ø60.8 × 5 mm · 4 pins Ø5 × 13.5 mm · output bore Ø5 mm

The set · Module 1 · 20° · spur

4 : 1 reduction: the ring is held, the sun is the input and the carrier the output.

Notes

Hardware: 4 × planet pin Ø5 × 13.5 mm.
Cantilevered pins: AGMA 6123 §10.7.3 keeps this to low face width to diameter ratios; retain each planet on its pin.

The link opens the whole set in the Planetary Gear Designer's 3D view. Change the teeth, the number of planets or stages, which member is held, the carrier, bores or hubs, then download STL, STEP or the carrier's DXF and SVG.

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