Overview
ISO 12167-1:2023 - "Plain bearings - Hydrostatic plain journal bearings with drainage grooves under steady‑state conditions - Part 1" defines calculation procedures for the design and assessment of oil‑lubricated hydrostatic plain journal bearings with drainage grooves. The standard covers steady‑state conditions and includes the design of the required lubrication system, including calculation of restrictor (capillary) data. It provides engineering methods to determine eccentricity, load‑carrying capacity, stiffness, lubricant flow rates, pumping and frictional power, and temperature/viscosity effects for hydrostatic bearings.
Key topics and technical requirements
- Calculation procedures for assessing a given bearing design and for designing a bearing from optional parameters (geometry, speed, load, lubricant).
- Lubrication system design, including restrictor sizing (capillaries) and pump feed pressure (system p = constant).
- Performance outputs: eccentricity, load‑carrying capacity, stiffness, lubricant flow rate, pumping power, frictional power, and temperature rise.
- Approximation methods: theoretical basis uses Reynolds equation; practical calculations rely on approximations derived from the Hagen–Poiseuille law (pressure‑driven flow) and Couette flow (drag flow due to shaft rotation). Annex A describes the approximation method and Annex B gives an example.
- Assumptions and boundary conditions: laminar flow, Newtonian incompressible lubricant, isoviscous behaviour in parts, rigid surfaces, constant axial clearance, constant pressure over recess areas, and no normal motion between surfaces.
- Design limits and similarity ranges: eccentricity range ε = 0…0.5 (typical practice), bearing width/diameter ratio B/D ≈ 0.3–1, recess depths typically 10–100× clearance gap height. The document also assumes an approximate optimal restrictor ratio ξ ≈ 1 for stiffness calculations.
- Normative linkage: references ISO 12167‑2:2021 (characteristic values used in calculations).
Practical applications and users
ISO 12167-1:2023 is intended for:
- Bearing designers creating hydrostatic plain journal bearings with drainage grooves.
- Rotating‑equipment and machine tool engineers specifying bearing performance (stiffness, damping, load capacity).
- Lubrication system designers sizing pumps and restrictors for oil‑fed hydrostatic bearings.
- Maintenance and reliability engineers assessing operating margins (temperatures, power losses, minimum film pressure).
- CAE and mechanical engineering teams implementing standardized calculation routines in design tools.
Use cases include high‑precision machine tool spindles, precision rotary tables, large slow‑speed shafts, and other applications where low wear, high stiffness and quiet operation are required.
Related standards
- ISO 12167‑2:2021 - Characteristic values for calculations of oil‑lubricated plain journal bearings with drainage grooves.
- Other parts of the ISO 12167 series (see ISO catalogue) for complementary guidance on hydrostatic plain bearings.
Keywords: ISO 12167-1:2023, hydrostatic plain journal bearings, drainage grooves, oil‑lubricated bearings, bearing calculation, restrictor design, lubrication system, load‑carrying capacity, pumping power, Reynolds equation.