| abstract |
A lubricating oil composition for wet clutches or wet brakes, which comprises a base oil and an inorganic phosphorus compound which may contain sulfur and/or oxygen atom(s) as the constituent element(s) or an amine salt of said compound, or which comprises a base oil, said inorganic phosphorus compound or amine salt thereof, and further an organic polyol compound having at least two hydroxyl groups in its molecule. This composition realizes excellent friction characteristics in wet clutches and brakes, in particular, a high µd (coefficient of kinetic friction) and a high µs (coefficient of static friction), a satisfactory suppression of vibration in lock-up clutches, an excellent persistence of the effect of vibration suppression, and the temperature-independency of the coefficients of friction. Hence this composition is useful as shock absorber oil, power steering oil, hydraulic suspension oil and so forth. |