The effects of gear oil on energy savings are examined using four-roller ma
chine and FZG gear machine. The influences of lubricating oil viscosity and
extreme-pressure additives, as well as load and rotational speed on fricti
on loss are experimented,It has become clear that the lower friction coeffi
cient is obtained by four-roller machine, and the smaller electric power co
nsumption by FZG gear machine. It has also become clear that the addition o
f friction modifier such as an organic molybdenum additive is effective in
energy savings. Furthermore, when the friction loss in the gear is calculat
ed, the friction coefficient at 100% or 120% slide/roll ratio measured with
four-roller machine is very sufficient.