OID / ENGINEERING TOOLS
Viscosity selection
Determine the reference viscosity, check an oil, or select an approximate ISO VG class for the operating temperature.
The specific bearing's data is entered manually.
REFERENCE MATERIAL
How to determine the inputs
Open the explanation, pick the applicable table, or step through the worked example.
Methodology and limits of applicability
OID, ch. 5, §5.5; formulas (11), (11a), (11b)
κ = ν / ν₁; dm = (d + D) / 2
ν₁ = 45,000·n⁻⁰·⁸³·dm⁻⁰·⁵ at n < 1000
ν₁ = 45,000·n⁻⁰·⁸³·dm⁻⁰·⁵ at n < 1000
At n ≥ 1000: ν₁ = 4500·n⁻⁰·⁵·dm⁻⁰·⁵. ν₁ in mm²/s, n in min⁻¹, dm in mm.
Input coefficients and requirements must correspond to the specific construction and duty. Missing values are never substituted automatically.
The ν(T) diagram assumes mineral oil with VI ≈ 95. It is a reference point; verify the actual oil's working viscosity against its datasheet.
What limits this calculation:
- data-sheet ν(T) curves of specific oils, other than mineral oils with VI ≈ 95