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 RPMWorm ISO VGHypoid ISO VG
600 – 3600460460
Under 600680460

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.

AUTOMOTIVE GREASESINDUSTRIAL GREASES