A friction energy approach to quantifying lubrication under fretting sliding

摘要

The problem of a proper lubrication under low-speed small oscillatory movement can be a decisive factor for the reliability of various components. There is a need to characterise the lubricious behaviour of the interface under oil-bath fretting wear conditions for ball bearing applications. Fast and reliable methods to quantify this behaviour for broad range of mechanical conditions are proposed and validated. Pure sliding reciprocation induces mixed lubrication mode. It was found that transient film profiles depend on the non-Newtonian response of the oils and the type of motion. Running-in period has a crucial importance for the tribofilm formation, and is a result of the interplay of the oil-sliding surfaces interface and is directly connected with the total energy dissipated from the contact region. The stability of structured tribofilm in steady-state period relies on the balance between the competitive processes: replenishment of the oil to the contact and ejection of the oil pending the oscillatory movement. The phenomenon of starvation was observed when the system was moved away from dynamical equilibrium and the growth of the dissipated energy was spotted. A proposed methodology provides the evaluation of the lubrication properties of the oil in a quantitative way.