While a number of
viscous fluids have no doubt been used
as gear lubricants, most of
these, other than the petroleum or
synthetic oils, are deficient in desirable characteristics. However, glycerol has
been suggested as a lubricant and
carrier for molybdenum disulfide.
The specific application in this case was
on small gear sets of the
worm and hypoid
types. Also, molasses was used as a transmission gear lubricant in
France during World War II.
The London Transport Company has
experimented with an inhibited castor
oil in the axles of certain buses. The thought behind this use was to reduce
the fuel consumption of the vehicles. Low viscosity oils or synthetic fluids were previously tried but with
such lubricants the necessary
damping effect was absent so that proper shifting was not
possible. Caution is given
that this application of castor oil is only possible
under the stop and go
operation of busses and would
not be possible in over the
road vehicles. The axle in this case
consists of a worm drive with a bronze worm wheel.
Gear pumps depend upon the fluid being handled as the lubricants, and this is sometimes water. Also, water has been employed as lubricant in the case of some nonmetallic gears but has its
limitations. First, the temperature range over which water can be used is
limited. Next, it will contribute to rusting of the ferrous parts with which it
comes in contact unless inhibitors are present. Further, water affords little
protection against wear.
