Xem Studiomeasured geometryLibrary › Stirling engines › Free-piston ·
Flexure hub centring bush: Ø5 and Ø8 OD × Ø3 / Ø5 bore × 6
How do I centre a flexure with a 5 mm hub hole on a 3 mm rod? · Hardware · basis: OD = flexure leaf hub bore (Ø5 for Ø60/Ø80 leaves, Ø8 for Ø100), ID = rod or tube, 6 long = two 2 mm leaf hubs and the 2 mm hub washer between them
Long Earth Society build part. The connecting parts of the tri-clamp free-piston engine. 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
- 4 in table
Notes
- A plain sleeve that centres flexure leaves whose hub hole is bigger than the rod: the two leaf hubs and the hub washer between them sit on its OD, the rod runs through its bore, and the two hub collars (bore = rod) clamp its ends.
- Hub-bush-60-b3 and hub-bush-80-b3: Ø5 OD × Ø3 bore × 6 for Ø60 / Ø80 leaves on the Ø3 displacer rod. hub-bush-100-b3: Ø8 × Ø3 × 6. hub-bush-100-b5: Ø8 × Ø5 × 6 for Ø100 leaves on the 5 mm tube piston rod.
Sizes
| file | od_mm | bore_mm | length_mm | for |
|---|---|---|---|---|
| hub-bush-60-b3 | 5 | 3 | 6 | Ø60 leaves, Ø3 rod |
| hub-bush-80-b3 | 5 | 3 | 6 | Ø80 leaves, Ø3 rod |
| hub-bush-100-b3 | 8 | 3 | 6 | Ø100 leaves, Ø3 rod |
| hub-bush-100-b5 | 8 | 5 | 6 | Ø100 leaves, 5 mm tube |
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.
| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| centring bush OD | leaf hub bore (Ø5 / Ø8) | flexure leaf hub | slide | hub-bush-* |
| centring bush bore | Ø3 / Ø5 | Ø3 rod / 5 mm tube | slide | hub-bush-* |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| NASA NTRS | Free-piston Stirling convertor flexure bearing development and life testing | US Government work | |
| Long Earth Society | Tri-clamp Stirling engine builds | web, video | LES site |
| Wikipedia | Free-piston engine | web | CC BY-SA 4.0 (text) |
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
| hub-bush-60-b3 | centring bush Ø5 OD × Ø3 ID × 6: fills the two leaf hubs and the hub washer (Ø5 bores) and centres them on the Ø3 displacer rod; the b3 collars clamp its ends | STEP · STL |
| hub-bush-80-b3 | centring bush Ø5 OD × Ø3 ID × 6: fills the two leaf hubs and the hub washer (Ø5 bores) and centres them on the Ø3 displacer rod; the b3 collars clamp its ends | STEP · STL |
| hub-bush-100-b3 | centring bush Ø8 OD × Ø3 ID × 6: fills the two leaf hubs and the hub washer (Ø8 bores) and centres them on the Ø3 displacer rod; the b3 collars clamp its ends | STEP · STL |
| hub-bush-100-b5 | centring bush Ø8 × Ø5 × 6: centres the Ø100 leaves and hub washer on the 5 mm tube piston rod | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=flexure-hub-centring-bush
How it fits
Goes in or on
Planar spiral flexure bearing leavesOD = leaf hub boreConnects to
Crankshafts Ø3, Ø5 and Ø8 with full-length D-flatØ3 displacer rod or 5 mm tube in the boreAlso needed
Flexure hub collarscollars clamp the stack endsIn these build lists
Free-piston Stirling, 2 in tri-clampNo crank: piston and displacer each hang on a stack of spiral flexures, with a t…Questions
How do I fit a 5 mm flexure hub on a 3 mm rod?
On the Ø5 × Ø3 × 6 centring bush: the two leaf hubs and the hub washer sit on its OD, the rod passes its bore, and hub collars clamp the ends.
Why is there a b5 bush only for Ø100?
The Ø60 and Ø80 leaves already have a Ø5 hub bore for the 5 mm tube; only the Ø100 leaves (Ø8 hub bore) need a Ø8 × Ø5 bush.