ISO 281:2007(E)
© ISO 2007 – All rights reserved iii
Contents Page
Foreword............................................................................................................................................................ iv
Introduction ........................................................................................................................................................ v
1 Scope ..................................................................................................................................................... 1
2 Normative references ........................................................................................................................... 1
3 Terms and definitions........................................................................................................................... 2
4 Symbols ................................................................................................................................................. 4
5 Radial ball bearings .............................................................................................................................. 6
5.1 Basic dynamic radial load rating......................................................................................................... 6
5.2 Dynamic equivalent radial load ........................................................................................................... 9
5.3 Basic rating life ................................................................................................................................... 10
6 Thrust ball bearings............................................................................................................................ 10
6.1 Basic dynamic axial load rating ........................................................................................................ 10
6.2 Dynamic equivalent axial load........................................................................................................... 12
6.3 Basic rating life ................................................................................................................................... 13
7 Radial roller bearings ......................................................................................................................... 13
7.1 Basic dynamic radial load rating....................................................................................................... 13
7.2 Dynamic equivalent radial load ......................................................................................................... 15
7.3 Basic rating life ................................................................................................................................... 16
8 Thrust roller bearings......................................................................................................................... 16
8.1 Basic dynamic axial load rating ........................................................................................................ 16
8.2 Dynamic equivalent axial load........................................................................................................... 19
8.3 Basic rating life ................................................................................................................................... 19
9 Modified rating life .............................................................................................................................. 20
9.1 General................................................................................................................................................. 20
9.2 Life modification factor for reliability ............................................................................................... 20
9.3 Life modification factor for systems approach ............................................................................... 21
Annex A (informative) Detailed method for estimating the contamination factor ..................................... 32
Annex B (informative) Calculation of the fatigue load limit ......................................................................... 42
Annex C (informative) Discontinuities in the calculation of basic dynamic load ratings......................... 47
Bibliography ..................................................................................................................................................... 51
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