Bearing Life
Basic rating life of a rolling bearing per ISO 281 — the life that 90 % of bearings are expected to reach — with an a₁ factor for higher reliability.
Adjusted life L_na5,197h
- Basic life L₁₀
- 452.1 million rev
- Basic life L₁₀h
- 5,197 h
- Load ratio C / P
- 7.68
- Calendar life
- 1.8 years
- P ≤ 0.5·C — beyond this the ISO 281 estimate is unreliable
- Target ≥ 20,000 h for continuously running general machinery
METHOD
How it is calculated
L₁₀ = (C / P)^p [million rev] p = 3 ball, 10/3 roller L₁₀h = 10⁶ · L₁₀ / (60 · n) L_na = a₁ · L₁₀
ASSUMPTIONS & NOTES
- C is the dynamic load rating from the bearing catalogue.
- Equivalent load P = X·F_r + Y·F_a; take X and Y from the catalogue for the bearing type and F_a/F_r ratio.
- The a_ISO factor for lubrication and contamination (ISO 281:2007) is not included.
Results are for preliminary design and checking; base the final design on the governing standard and safety factors.
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