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Swash (wobble) plate: Ø40 plates at 10, 15 and 20° with a ball-end follower

How do I make a swash plate (wobble plate) drive with 3D printed parts? · Hardware · basis: Swash plate geometry: a follower at radius r on a plate tilted θ moves r·sin θ each side (stroke 2r·sin θ); Ø5 shaft

Long Earth Society build part. Multi-cylinder drive from one shaft, used on the LES rigs. The engines

Exact dimensions. Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part. Mating features

sizes
3 in table

Notes

  • A disc fixed at an angle on a shaft; a follower pressed against it reciprocates once per turn.
  • Stroke = 2 × r × sin θ for a follower at radius r. At the Ø40 rim: 6.9 mm at 10°, 10.4 mm at 15°, 13.7 mm at 20°.
  • Several followers spaced around one plate drive several cylinders from one shaft.
  • The follower is an 8 mm square pushrod with a Ø8 ball end and a Ø3 hole in its tail.

Sizes

platetiltstroke at rim (r 20)stroke at r 18
Ø4010°6.9 mm6.3 mm
Ø4015°10.4 mm9.3 mm
Ø4020°13.7 mm12.3 mm

Mating features

Drawn at the exact size. Open press, slide, run and socket features by your process's clearance; leave designed gaps and clamp fits as drawn.

featureexactmates withfitfiles
hub boreØ5Ø5 shaftslideswash-plate-*
set-screw holeØ2.5M3 tap drilldesignedswash-plate-*
follower tail holeØ3Ø3 pinrunswash-follower-*

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

WikipediaSwashplatewebCC BY-SA 4.0 (text)
Long Earth SocietyEngine and rig builds on extrusion framesweb, videoLES site

Free files

★ Free files 4 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json

swash-plate-40-10degswash (wobble) plate Ø40, 10° tilt, 6.9 mm stroke at the rim, Ø5 shaft, Ø2.5 set-screw holeSTEP · STL
swash-plate-40-15degswash (wobble) plate Ø40, 15° tilt, 10.4 mm stroke at the rim, Ø5 shaft, Ø2.5 set-screw holeSTEP · STL
swash-plate-40-20degswash (wobble) plate Ø40, 20° tilt, 13.7 mm stroke at the rim, Ø5 shaft, Ø2.5 set-screw holeSTEP · STL
swash-follower-8x30swash follower: 8 mm square pushrod with a Ø8 ball end, Ø3 tail holeSTEP · STL

Plain text: sheet.txt · JSON: /api/geometry?object=swash-plate

Swash (wobble) plate: Ø40 plates at 10, 15 and 20° with a ball-end follower, isometric render of a generated part
Render of swash-plate-40-15deg from the free STEP; not to scale.

How it fits

Goes in or on

Stirling shafts and rodsØ5 shaft through the hub

Alternatives

Scotch yokesingle-cylinder sine motionEccentric and strapsingle strap drive

Also needed

Shafts, D-flats, set-screw collars, E-clips and…locate the plate on the shaft

You might also need

Ball bearings, 683 to 6210 and flanged F6xx (ISO 15), isometric render of a generated part
Ball bearings, 683 to 6210 and flanged F6xx (ISO 15)44 sizes★ 44 files

Questions

How much stroke does a swash plate give?

Stroke = 2 × r × sin θ for a follower at radius r on a plate tilted θ: Ø40 plate, follower at r = 18, 15° gives 9.3 mm.

Can one plate drive more than one cylinder?

Yes. Space followers around the plate; each one reaches top of stroke at a different shaft angle, set by its position around the plate.