ISO 281-2007 PDF

Full title and description

ISO 281:2007 — Rolling bearings — Dynamic load ratings and rating life. Specifies internationally agreed methods for calculating basic dynamic load ratings and rating life (L10 and modified rating life) for conventional rolling bearings manufactured from commonly used high‑quality hardened bearing steel, and sets exclusions and applicability limits for those calculation methods.

Abstract

ISO 281:2007 defines the methods to determine basic dynamic radial and axial load ratings for ball and roller bearings, the calculation of basic rating life (defined for 90 % reliability) and modified rating life accounting for different reliabilities, lubrication conditions, contaminated lubricants and fatigue loading. The standard excludes effects such as wear, corrosion and electrical erosion and does not apply where rolling elements operate directly on a shaft or housing surface unless that surface is fully equivalent to a bearing raceway.

General information

• Status: Published (International Standard; confirmed following periodic review).
• Publication date: 22 February 2007 (Edition 2, 2007).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 21.100.20 — Rolling bearings.
• Edition / version: Edition 2 (2007).
• Number of pages: 51 pages.

Core bibliographic details and confirmation status are recorded by ISO.

Scope

Specifies calculation methods for basic dynamic load ratings and rating life for rolling bearings within the size ranges covered by relevant ISO bearing publications. Applies to bearings of conventional design made from commonly used, high‑quality hardened bearing steel produced to good manufacturing practice. Covers radial and thrust (axial) ball bearings and radial and thrust roller bearings, and provides procedures for deriving equivalent dynamic loads and modified rating life factors. Does not address wear, corrosion, electrical erosion or non‑conventional designs where rolling elements run directly on non‑raceway surfaces.

Key topics and requirements

• Definitions and symbols for load ratings and life calculations (basic dynamic radial and axial load ratings).
• Formulas and procedures to calculate dynamic equivalent radial and axial loads for bearings under combined or variable loading.
• Calculation of basic rating life (L10), conventionally associated with 90 % reliability, and the mathematical life model used (life in revolutions and hours).
• Methods to calculate modified rating life accounting for different reliability targets, lubrication conditions, lubricant contamination and fatigue loads.
• Limits of applicability: material and design assumptions (conventional hardened bearing steel and conventional raceway geometries) and exclusions (wear, corrosion, electrical erosion, non‑raceway operation of rolling elements).
• Data and factors required for practical life estimates (load factors, geometry parameters, contact stress / fatigue limits as applicable).

Typical use and users

Used by bearing designers and manufacturers, mechanical design and rotating‑equipment engineers, reliability and maintenance engineers, tribologists, standards committees and technical purchasers to size bearings, estimate fatigue life and compare bearing options for machinery and equipment. Also used as a normative reference in product specifications and technical procurement documents.

Related standards

Related and predecessor documents include ISO 281:1990 and its amendments, technical specification ISO/TS 16799 (withdrawn, replaced by ISO 281:2007), and explanatory technical reports such as ISO/TR 1281‑1 which provide background and derivation notes for the equations and factors in ISO 281:2007. Users often consult other bearing and lubrication standards alongside ISO 281 when performing detailed bearing life and reliability assessments.

Keywords

rolling bearings, dynamic load rating, basic dynamic load rating, basic rating life, L10 life, modified rating life, equivalent dynamic load, fatigue limit, bearing life calculation, bearing design.

FAQ

Q: What is this standard?

A: ISO 281:2007 is an International Standard that specifies calculation methods for the basic dynamic load ratings and rating life of conventional rolling bearings.

Q: What does it cover?

A: It covers formulas and procedures for deriving basic dynamic radial and axial load ratings, calculating basic rating life (L10) and modified rating life for different operating and lubrication conditions, and defines applicability limits and exclusions (for example, it does not address wear, corrosion or electrical erosion).

Q: Who typically uses it?

A: Bearing manufacturers, mechanical design engineers, reliability engineers, maintenance planners, tribologists and standards writers use ISO 281:2007 to size bearings, estimate fatigue life and specify bearing requirements in design and procurement.

Q: Is it current or superseded?

A: ISO 281:2007 is the currently published edition (Edition 2, 2007) and, according to ISO records, the document was reviewed and confirmed (remains current) during the ISO five‑year review cycle (confirmation noted in 2021).

Q: Is it part of a series?

A: ISO 281 relates to a body of ISO documents on rolling bearings. There are predecessor editions and related technical specifications and technical reports (for example ISO 281:1990, ISO/TS 16799:1999 and explanatory reports such as ISO/TR 1281‑1) that provide supplementary information and historical context.

Q: What are the key keywords?

A: Rolling bearings, dynamic load rating, basic rating life, L10, modified rating life, equivalent dynamic load, fatigue limit, lubrication, bearing life calculation.