Hydrostatic shallow-pocket liquid thrust bearing — fixed reference geometry

Reference-geometry calculator (Ø40mm bearing, 5µm film — fixed, matching the original) for a hydrostatic shallow-pocket liquid thrust bearing fed through a small central inlet hole. Vary pocket/inlet diameter, pressures and viscosity.

✓ validated against legacyoriginal: /calculators/c11_1a.htm

Hydrostatic shallow-pocket liquid thrust bearing — fixed reference geometry — original diagram from /calculators/c11_1a.htm

Pocket diameter, 2R₁10⁻³ mInlet diameter, 2R₂10⁻³ mSupply pressure, pₛ10⁶ PaAmbient pressure, pₐ10⁶ PaViscosity, ηPa·s

Load capacity, F283.4 N

Dimensionless load, F′0.564

Inherent stiffness, S = −dF/dh24.2 10⁶ N/m

Flow rate, Q0.232 10⁻³ l/min

Dimensionless flow, Q′1.549

Pressure factor, β0.66

The legacy "please login" demo lock froze D0/H0/H2 to these exact values. Per docs/phase6/OWNER-DECISIONS-BACKLOG.md K4, this fixed geometry is kept exactly as in the original and only the inputs that were already free under the lock are exposed. Generalizing it is a deliberate future decision for Anton, not made here.

Method & references

The larger the pocket 2R₁, the larger the load capacity and self-aligning capability.
A smaller inlet 2R₂ favors self-alignment but may cause a local pressure drop from inertia forces.
FIXED GEOMETRY: bearing diameter 40 mm, film thickness 5 µm, pocket depth = film thickness — the original demo lock froze these three together.

The computation is a literal port of the original client-side JavaScript from /calculators/c11_1a.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.

Hydrostatic shallow-pocket liquid thrust bearing — fixed reference geometry — Engineering ABC