Required loads in. Three feasible conical-bearing candidates out.
This public case closes the gap between saying that AURA supports inverse design and showing a reproducible, bounded result. The design question starts with required performance and a locked shaft interface—not a preselected bearing geometry.
1. Requirements and fixed decisions
| Input | Value | Role in this case |
|---|---|---|
| Support architecture | Opposed conical pair | Axial stiffness projected to the machine axis as Knormal sin²α. |
| Pressure basis | Absolute | Supply candidates are evaluated against pa = 1.0 bar absolute. |
| Radial criterion | Er,req ≤ 0.70 | Required radial equilibrium ratio must remain inside the screening limit. |
| Axial criterion | Ez,req ≤ 0.70 | Required axial equilibrium ratio must remain inside the screening limit. |
| Operating speed | 20,000 rpm | Recorded as a downstream machine requirement; not used to rank this static inverse search. |
2. Search and ranking
- Generate. The solver evaluates 4,032 combinations across bounded cone angle, length, clearance, supply pressure and feed configuration while preserving the 30 mm shaft interface.
- Reject. Invalid physical/model states are removed before feasibility scoring; 630 combinations were rejected in this run.
- Filter. Both radial and axial screening criteria must pass. The run returned 399 feasible states.
- Rank. The published set deliberately represents three engineering preferences: balanced margin, compact envelope and lower supply pressure.
3. Candidate comparison
| Candidate | Geometry | Supply / flow | Static outputs | Required ratios |
|---|---|---|---|---|
| Balanced margin Top-ranked balanced state | α 60° · L 32.0 mm C 20 µm · Rout 70.43 mm | 5.0 bar abs 2.72 m³/h | Kr 10.38 N/µm Ka 65.17 N/µm Wr,max 145.39 N Wa,max 912.35 N | Er 0.385 Ez 0.276 |
| Compact envelope Smallest published radial envelope | α 50° · L 22.4 mm C 20 µm · Rout 41.70 mm | 8.0 bar abs 4.35 m³/h | Kr 9.50 N/µm Ka 30.62 N/µm Wr,max 133.03 N Wa,max 428.69 N | Er 0.421 Ez 0.588 |
| Lower pressure Lowest published supply pressure | α 60° · L 48.0 mm C 30 µm · Rout 98.14 mm | 3.0 bar abs 2.45 m³/h | Kr 6.48 N/µm Ka 60.54 N/µm Wr,max 136.06 N Wa,max 1,271.27 N | Er 0.412 Ez 0.198 |
Why three answers? Inverse design does not remove engineering judgment. It makes the trade-off explicit. A compact state requires more pressure and flow; the lower-pressure state needs a much larger radial envelope; the balanced state retains the largest minimum screening margin of the published set.
4. Controlled handoff
What can move downstream
Case identity, fixed interface, geometry, absolute-pressure basis, feed architecture, static load capacities, projected stiffnesses, flow estimate and screening criteria can enter the machine-configuration record.
What is still missing
Manufacturing tolerances, frequency-dependent coefficients, thermal and pneumatic transients, complete rotor eigenanalysis, stability margin, uncertainty propagation and case-level experimental correlation.
5. Reproducibility record
The public JSON record contains inputs, search counts, constraints, all three candidates and the evidence boundary. The solver remains proprietary, but the published result is no longer an unsupported capability statement.