Effective Viscosity of Polymer Thickened Oils in Gear Lubrication

Some new insights on the special features of gear lubrication in relation to the effective viscosity of polymer thickened oils were obtained by experiments using an IAE gear tester. It was found that the load carrying capacity of multigrade oils correlates with the viscosity after a 60 min sonic shear stability test and the change of bulk viscosity during operation of a gear system can be calculated from the EHL film thickness and the assumed extent of viscosity loss in sheared area.