Abstract
In this paper, as the first step to get a key to clarification of the mechanism of scoring in gear pairs, effect of surface roughness on the seizure limit of non-additive gear oil was examined by two-cylinder tests. As the result, the following conclusions are deduced : (1) In the lower range of specific slidings and the slower range of sliding velocities where seizure occurs in boundary lubrication, the seizure limit is not affected by surface roughness or rather it increases as surface roughness increases. (2) In the higher range of specific slidings where seizure tends to occur in mixed or full elastohydrodynamic lubrication regardless of surfaced roughness, the seizure limit decreases as surface roughness increases. (3) In order to increase the seizure limit in the higher range of specific slidings and the faster range of sliding velocities where seizure occurs easily and to decrease the frictional power loss, finishing the surface roughness fine is an effective means.
