| Symbol | κ |
|---|---|
| Unit | - |
| Attribute-ID | viscosity_ratio |
| Numeric ID | 14138 |
| Value Type | PMDouble |
The viscosity ratio κ can be determined as follows:
If the SKF/Heemskerk option is selected, the calculation is essentially the same as according to ISO 281; however, the determination of the kinematic reference viscosity at speeds < 1000 1/min is carried out using the factor n-0.83333333333 instead of the ISO factor n-0.83. This results in no discontinuity in the reference viscosity at speeds below and above 1000 1/min.
Note: For the calculation of the factor a_SKF for the SKF catalog service life, a formula deviating from ISO 281 is used to determine the reference viscosity (as long as the viscosity ratio is not specified by the user).
Heemskerk, R. EHD lubrication in rolling bearings – review of theory and influence on fatigue life. Stratto da Tribologia e Lubrificazione, 1980, 4, 3–7.