DIN Standards Committee Petroleum and Natural Gas Industries
DIN ISO 281
Rolling bearings - Dynamic load ratings and rating life (ISO 281:2007)
Wälzlager - Dynamische Tragzahlen und nominelle Lebensdauer (ISO 281:2007)
Overview
This International Standard specifies methods of calculating the basic dynamic load rating of rolling bearings within the size ranges shown in the relevant ISO publications, manufactured from contemporary, commonly used, high quality hardened bearing steel, in accordance with good manufacturing practice and basically of conventional design as regards the shape of rolling contact surfaces. This document also specifies methods of calculating the basic rating life, which is the life associated with 90 % reliability, with commonly used high quality material, good manufacturing quality and with conventional operating conditions. In addition, it specifies methods of calculating the modified rating life, in which various reliabilities, lubrication condition, contaminated lubricant and fatigue load of the bearing are taken into account. This International Standard does not cover the influence of wear, corrosion and electrical erosion on bearing life. This document is not applicable to designs where the rolling elements operate directly on the shaft or housing surface, unless that surface is equivalent in all respects to the bearing ring (or washer) raceway it replaces. Double-row radial bearings and double-direction thrust bearings are, when referred to in this document, presumed to be symmetrical. Further limitations concerning particular types of bearings are included in the relevant clauses. The following corrections have been made with respect to DIN ISO 281:2009-01: a) The German translation in 5.1.2.3 regarding the calculation of the basic dynamic radial load rating for a tandem arrangement ("Anzahl der Lager multipliziert mit der 0,7fachen Tragzahl eines einreihigen Lagers" shall be changed to read: "Anzahl Lager hoch 0,7 multipliziert mit der Tragzahl eines einreihigen Lagers" ("number of bearings to the power of 0,7 times the rating of one single-row bearing")). b) The German translation in 7.1.2.3 regarding the calculation of the basic dynamic radial load rating for a tandem arrangement ("Anzahl der Lager multipliziert mit der (7/9)-Potenz der Tragzahl eines einreihigen Lagers" shall be changed to read: "Anzahl Lager hoch 0,7 multipliziert mit der Tragzahl eines einreihigen Lagers" ("number of bearings to the power of 7/9, times the rating of one single-row bearing")). This document (ISO 281:2007) has been prepared by Technical Committee ISO/TC 4/SC 8 "Load ratings and life"), the secretariat of which is held by DIN (Germany). The responsible German Committee is Working Committee NA 118-01-08 "Tragzahlen und Lebensdauer" ("Load ratings and life") of the Rolling Bearings and Plain Bearings Standards Committee (NAWGL).
