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Life Formula Spec Table
Life Formula KS Specifications — 5 sizes
KS B 2021ISO 281ISO 281:2007
KSLife Formula
5 sizes| Item | Exponent p | Formula | Unit | Note | Standard |
|---|---|---|---|---|---|
| Bearing (Ball) | 3 | L₁₀ = (Cr/P)³ × 10⁶ rev | rev | ∝ 1/n | KS B 2021 |
| Bearing (Roller) | 10/3 | L₁₀ = (Cr/P)^(10/3) × 10⁶ rev | rev | ∝ 1/n | ISO 281 |
| - | L_h = L₁₀ × 10⁶ / (60·n) | h | n: rpm | ISO 281 | |
| P | - | P = X·Fr + Y·Fa | N | X·Y: Bearing | ISO 281 |
| - | L_na = a₁·a₂·a₃·L₁₀ | h | ·· | ISO 281:2007 |
Reference section for the L₁₀ basic rating life formulas per ISO 281 / KS B 2021. Ball bearings use a load exponent p = 3; roller bearings use 10/3. Life in millions of revolutions equals (Cr/P)^p, where Cr is the basic dynamic load rating and P is the equivalent dynamic load. Life in hours is L_h = L₁₀·10⁶/(60n); corrected life is L_na = a₁·a₂·a₃·L₁₀. Equivalent dynamic load is P = X·Fr + Y·Fa, with X/Y factors looked up per bearing type.