Equivalent dynamic bearing load
kN
Mechanics · Bearings
Bearing Equivalent Dynamic Load Calculator
Combine radial and axial load components with bearing-specific dynamic factors before a basic rating-life calculation.
Created v1.0
By Thibaut Grzelak, Mechanical Analysis Engineer
03
MetricResults
Radial contribution
kN
Axial contribution
kN
View calculation detailsFormulas, SI conversion, numerical substitution and resultsOpen ↓
Calculation note
Full calculation details
X and Y are user-supplied dynamic factors from documentation applicable to the bearing. Fr and Fa represent the studied load case. The model selects neither a bearing type nor an e threshold and does not replace manufacturer data. Some catalogues impose piecewise rules based on Fa/Fr or e, and sometimes a minimum load; this result only applies the entered factors. Variable-load spectra, shock and additional dynamic effects are excluded.
01Formulas and symbols
Formulas used
P
X × Fr + Y × FaEquivalent dynamic bearing loadXFr
X × FrRadial-load contributionYFa
Y × FaAxial-load contribution02Assumptions and limits
Scope of validity
- X and Y are user-supplied dynamic factors from documentation applicable to the bearing.
- Fr and Fa represent the studied load case.
- The model selects neither a bearing type nor an e threshold and does not replace manufacturer data.
- Some catalogues impose piecewise rules based on Fa/Fr or e, and sometimes a minimum load; this result only applies the entered factors.
- Variable-load spectra, shock and additional dynamic effects are excluded.
03Validation example
Reference numerical case
- Fr = 5 kN, Fa = 2 kN, X = 0.56 and Y = 1.60.
- XFr = 2.8 kN and YFa = 3.2 kN.
- P = 6.0 kN.
04Frequently asked questions
Questions about the calculation
Where do X and Y come from?
Use the manufacturer catalogue or technical data for the bearing type, geometry and applicable load conditions.
Can X = 1 and Y = 0 always be used?
No. They represent only the initial purely radial example here. Axial load or another regime may require different factors.
Is P the basic dynamic load rating C?
No. P is the applied equivalent dynamic load; C is a bearing rating used later in the L10 relation.
05References
Technical references
- ISO 281:2007, Rolling bearings — Dynamic load ratings and rating life.
- ISO/TR 1281-1:2021, explanatory notes on ISO 281.
- Bearing manufacturer data for X, Y and their conditions of application.