Rolling-bearing rating life
A clear explanation of basic L10 rating life and the information it does not provide.
ENGINEERING PRINCIPLE
Basic rating life relates dynamic capacity to equivalent dynamic load using an exponent that depends on bearing type.
L₁₀ = (C/P)^p × 10⁶ revolutionsVariables and units
- C = dynamic rating (N)
- P = equivalent dynamic load (N)
- p = 3 for radial ball bearings
Worked example
With C = 19,500 N, P = 6,500 N and p = 3, L10 = 27 million revolutions. At 1,450 rpm this is about 310 hours.
Calculation method
- Determine equivalent dynamic load for the duty cycle.
- Use the correct bearing-type exponent and capacity from the catalogue.
- Convert revolutions to service hours at the actual speed.
Practical applications
- Motor bearings
- Gearbox supports
- Rotating process machinery
Review boundary and reference
- L10 is a statistical basic-life rating, not a guaranteed service life.
- Lubrication, contamination, reliability and alignment can dominate field performance.
Formula and displayed units independently checked for the stated conditions. This is not a code-compliance design method.
Source: ISO 281:2007, Rolling bearings — Dynamic load ratings and rating life.