Rolling-Bearing Dynamic Equivalent Load P (ISO 281)

Combining the actual radial load Fr and thrust Fa into the single number a rating-life calculation needs (ISO 281). For a single-row deep-groove ball bearing, P = X Fr + Y Fa, with the e-ratio and thrust factor Y interpolated from the standard ISO 281 / SKF table on Fa/C0 (C0 the basic static rating). Below e the pure radial load governs (X = 1, Y = 0, P = Fr); above it X = 0.56 and Y applies. Fr = 1,000, Fa = 500, C0 = 5,000 gives Fa/C0 = 0.10 (e = 0.29, Y = 1.5), and since Fa/Fr = 0.5 > e, P = 0.56 x 1,000 + 1.5 x 500 = 1,310 lbf - 31% above the radial load, which by the cube law cuts L10 to about 44%. Drop the thrust and P = Fr = 1,000, exactly the P an L10 rating-life calculation takes. Deep-groove ball bearings, rotating inner ring; other types use the maker's factors. A planning estimate; ISO 281 and the bearing catalogue govern.

P = X Fr + Y Fa. Single-row deep-groove ball: interpolate e and Y from the ISO 281 / SKF table on Fa/C0 ([0.025,0.22,2.0]...[0.50,0.44,1.0]); if Fa/Fr <= e then X = 1, Y = 0 (P = Fr), else X = 0.56.

The ISO 281 dynamic equivalent load P = X Fr + Y Fa with the standard single-row deep-groove ball-bearing X/Y/e table vs Fa/C0 (ISO 281; SKF General Catalogue; Shigley's Mechanical Engineering Design), by name; feeds the bearing-l10-life and bearing-max-load tiles.

The equivalent-load relation and the deep-groove ball X/Y/e table are published ISO 281 / catalogue data; the radial and thrust loads and the static rating C0 come from the application and the bearing catalog.

Estimate. AHJ and licensed professional govern.

Field names used by the API: radial_load_lbf, thrust_load_lbf, static_rating_lbf, equivalent_load_lbf, e_ratio

• Equivalent load P = X Fr + Y Fa; X = 0.56 for Fa/Fr > e, else X = 1 and Y = 0ISO 281
• X/Y/e table single-row deep-groove ball, e and Y interpolated on Fa/C0 (0.025->0.50)ISO 281 / SKF catalogue
• Scope deep-groove ball, rotating inner ring V = 1; other bearing types use maker factorsscope of this tile