What Is ISO 281?
ISO 281 is the international standard for calculating the rating life of rolling bearings. It defines the basic L10 life formula: L10 = (C/P)^p x 10^6 revolutions, where C is the basic dynamic load rating, P is the equivalent dynamic load, and p is the life exponent (3 for ball bearings, 10/3 for roller bearings).
Modified Rating Life
The modified life formula L10m = a1 x aISO x L10 incorporates reliability factor (a1), lubrication condition (kappa), and contamination level (eC). See the Bearing Selection Guide for worked examples.
Frequently Asked Questions
What does ISO 281 define?
ISO 281 defines the calculation method for the basic rating life (L10) of rolling bearings based on the dynamic load rating (C) and the equivalent dynamic load (P). It also covers the modified rating life (L10m) that accounts for reliability, lubrication, and contamination factors.