抄録
The rheological properties of solidified lubricant oils and solidified traction oils used in continuously variable transmissions (CVTs) under pressure were evaluated by observing large plastic deformation of metal microspheres (about 0.07 mm), occurring due to non-hydrostatic pressurization in these oils using a diamond-anvil pressure cell. The solidification pressure values obtained by observing aluminum sphere deformation were almost equal to those extrapolated from high-pressure viscosity (2GPa for lubricant oils and 0.6GPa for traction oils); thus, aluminum sphere deformation experiments are effective for evaluating solidification pressure. Shear stresses of the solidified oils could be estimated up to 9 GPa from the deformed Cu spheres based on several assumptions. The obtained stresses for traction oils were almost equal to the mean shear stress obtained from a traction test between 1.0 GPa and 1.7 GPa and were below it for pressures above 1.7 GPa. The stress values for ester oils and vegetable oils were small.
