Description:Abstract
A radial piston hydraulic motor has several components that encounter sliding or
rolling motion under lubricated conditions. When a hydrostatic, hydrodynamic or
elastohydrodynamic oil film separates the interacting surfaces, the wear and friction
are low provided of course the hydraulic fluid is free from the presence of
contaminants. Mixed lubrication may occur even at relatively high speed when using
low viscosity fluids and may result in increased friction which adversely affects the
operating efficiency of the hydraulic motor. Additionally, the increased heat
accumulation at different interfaces of the motor under extreme operating conditions
involving high pressures, high speeds and low viscosities can also lead to unstoppable
thermal process resulting in seizure. At low speeds, different tribological pairs operate
in boundary lubrication regime and are prone to wear. The associated high friction can
also result in low starting efficiency.
The research work reported here has thus focussed on addressing the above mentioned
questions so as to improve understanding of the tribological phenomena and find ways
for improving and alleviating hydraulic motor tribological components.
The results have shown that it is possible to reduce both the boundary friction and the
lift-off speed through proper choice of surface modification methods and their
application on motor components.