Bearing Life (L10)

ISO 281 basic rating life L₁₀ = (C/P)ᵖ million revolutions, p = 3 (ball) or 10/3 (roller). At speed n, L₁₀ₕ = L₁₀·10⁶/(60·n). C, P in N; n in rpm.

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Give the basic static rating C₀ and a ball bearing’s X and Y are read off Shigley’s Table 11–1: e and Y₂ interpolate on Fa/C₀, with X₂ = 0.56. Clear C₀ to type a catalogue pair instead. V is 1 with the inner ring rotating, 1.2 with the outer. Below e the equivalent load is V·Fr alone, so P is never taken below the radial load. Bearings whose below-e rule is Fr + Y₁·Fa — spherical roller, double-row angular contact — need that pair entered when Fa/(V·Fr) ≤ e.