INDUSTRIAL GREASES

Detail Description
Coefficient of Lubricant Friction or Duty Parameter is proportional to Viscosity x Speed/Load
- λ=H/S, where λ = Specific Film Thickness, H = Minimum Film Thickness,
S = Composite average surface roughness
Full Film Lubrication λ > 3
Mixed Film Lubrication 1< λ < 3
Boundary Lubrication λ < 1 - Approximately SUS = Kinematic Viscosity @ 40 ºC / 5
- Viscosity (cSt) = Dynamic Viscosity (cP) / Density (g/cc)
- Arrhenius law: Oxidation rate doubles for every 10 ºC rise in temperature.
SIMPLIFIED VISCOSITY SELECTION FOR WORM AND HYPOID GEARS
| Speed RPM | Worm ISO VG | Hypoid ISO VG |
| 600 – 3600 | 460 | 460 |
| Under 600 | 680 | 460 |
GEAR OILS
- Erichello Method:
Viscosity @ 40 ºC = 7000÷√V1
V1 = Pitch line velocity of the lowest speed gear in feet per minute (fpm) = 0.262 x speed (pinion RPM) X pinion diameter (inches) - If ambient at 95 ºF increase jump ISO Grade by one step.
- If ambient at 122 ºF increase ISO Grade by two.
