ISO 6834:2022

Overview

ISO 6834:2022 - "Plain bearings - Thermo-hydrodynamic lubrication design charts for circular cylindrical bearings under steady‑state conditions" - provides a practical calculation procedure and design charts to determine the maximum bearing temperature and effective dynamic viscosity in the lubricant film of oil‑lubricated, statically loaded hydrodynamic plain journal bearings. Applicable to circular cylindrical bearings with an angular span Ω = 360° and width ratio B* in the range 0.5 to 1.5, the standard targets steady‑state, fluid‑lubricated operation. The procedure produces results that satisfy the energy balance without requiring complex numerical iteration, and its outputs can feed into ISO 7902‑1:2020 bearing performance calculations.

Key topics and technical requirements

• Calculation objective: determine maximum bearing temperature (T_B,max) and effective lubricant film viscosity (η_eff) under steady conditions.
• Design charts: bearing characteristics are read from charts that use four dimensionless numbers computed from bearing geometry, operating conditions and lubricant viscosity properties. Examples of dimensionless parameters appearing in the document include the S (Sommerfeld) number and Pe (Peclet) number.
• Model basis and equations (summarized in the standard): generalized Reynolds equation, energy equation for the lubricant film, temperature–viscosity relationship, film thickness and axial contraction formulas, zero‑net‑heat‑flow method for journal surface temperature, and load–film reaction balance.
• Inputs and preconditions: bearing dimensions (D, B, clearance), operating speed and load, lubricant supply temperature and viscosity data, and assumed boundary conditions for steady‑state hydrodynamic lubrication.
• Deliverables: maximum bearing temperature, effective dynamic viscosity in the film, and guidance on converting chart (dimensionless) results to dimensional values. Annex A provides calculation examples.

Applications and users

ISO 6834:2022 is useful for:

• Bearing designers and mechanical engineers performing thermal and tribological design of plain journal bearings.
• Rotating‑machinery OEMs and component suppliers validating bearing operating temperatures and lubricant selection.
• Tribologists and maintenance engineers assessing bearing life, lubrication regimes and thermal limits.
• Analysts seeking reliable input data (η_eff, T_B,max) for further hydrodynamic performance calculations (e.g., ISO 7902‑1:2020).

Keywords: ISO 6834:2022, thermo‑hydrodynamic lubrication, plain bearings, journal bearings, design charts, effective dynamic viscosity, maximum bearing temperature, Sommerfeld number, Peclet number.

Related standards

• ISO 7902‑1:2020 - Hydrodynamic plain journal bearing performance calculations (useful for further load/film analysis).
• ISO 4378‑1 - Terms, definitions and symbols for plain bearings (normative references used by ISO 6834:2022).