Overview
ISO 20015:2017 - "Spherical plain bearings - Method for the calculation of static and dynamic load ratings" specifies standardized methods to calculate static load ratings and dynamic load ratings for spherical plain bearings within the size ranges covered by ISO 12240‑1, ISO 12240‑2 and ISO 12240‑3. Rod ends (ISO 12240‑4) are explicitly excluded. The standard defines terms, symbols and calculation procedures for radial, angular contact radial and thrust spherical plain bearings, and includes informative annexes explaining factors and a worked calculation example.
Key topics and requirements
- Scope and definitions: clear definitions for static and dynamic conditions, including static radial/axial and dynamic radial/axial load ratings.
- Calculation methods: prescriptive formulae for:
- Radial spherical plain bearings (static and dynamic)
- Angular contact radial spherical plain bearings (static and dynamic)
- Thrust spherical plain bearings (static and dynamic)
- Geometrical parameters: calculations use bearing dimensions such as bore (d), outer diameter (D), sphere diameter and ring widths (B, C, S1, S2) as defined in ISO 12240 series.
- Material and design factors (f): the standard requires use of factors (f0r, fr, f0a, fa) that depend on sliding materials, surface treatments, heat treatment and design features (seals, lubrication grooves). These factor values are not defined in ISO 20015 and should be obtained from the manufacturer.
- Annexes: Annex A explains the influence of materials and design on the f factors; Annex B provides a calculation example to illustrate application.
Applications and users
ISO 20015:2017 is practical for:
- Bearing manufacturers - to supply standardized load rating data and to define the f factors for product ranges.
- Design and mechanical engineers - to size and specify spherical plain bearings for machines, hydraulic cylinders, pivots and articulating joints where spherical plain bearings are used.
- Procurement and quality teams - to compare supplier data and ensure compliance with ISO load‑rating calculation methods.
- Standards and testing bodies - for harmonized reporting of static and dynamic load capacities.
Practical uses include generating consistent static and dynamic load rating values for product datasheets and engineering specifications; engineers use these ratings to determine allowable loads and to ensure compatibility between bearing geometry and application loads.
Related standards
- ISO 12240‑1, ‑2, ‑3 - dimensional definitions for radial, angular contact radial and thrust spherical plain bearings
- ISO 12240‑4 - rod ends (excluded from ISO 20015 calculations)
- ISO 6811 - vocabulary for spherical plain bearings
Keywords: ISO 20015:2017, spherical plain bearings, static load rating, dynamic load rating, ISO 12240, bearing load calculation, radial bearings, thrust bearings, angular contact bearings.