SBIR-STTR Award

Solid lubrication offers significant advantages for rolling element bearings and machinery exposed to extreme conditions. A major constraint is that current designs for such bearings are based on hydrodynamic lubrication (oil and grease). The challenge is to identify a new concept that focuses the requirements for the effective use of solids and a methodology for solid lubricant-bearing system integration. The concept being proposed is that the bearing and lubricant are interdependent and compatibility involving (1) environment (2) lubricant-bearing interface and (3) bearing design parameters is a critical factor. For bearing operation targeted at 1000/1500 degree F and dn in excess of 1m, the opportunity to pursue this concept will emphasize emerging complex sulfur containing compounds (e.g. Oxythiomolybdates) coupled with technical ceramics as the primary Phase I effort. Critical interfaces will involve roller race, roller-separator and separator-land with solid lubricant replenishment from multiple sites on land-separator with solid lubricant replenishment from multiple sites on land-separator components. Analyses will include thermal effects and load limits. The results will establish important life controlling properties and preliminary design guides for solid lubricated high temperature bearings.

The objective of this project is to develop a self-contained, solid lubricated rolling bearing (30 - 40 mm bore) having the following performance characteristics: operating capability in the 1000 - 1500 deg F range; suitable for the speed range of 40,000 - 50,000 rpm; compatible with gas turbine engine structure; minimum life of three five hours. This effort will center on vital design parameters including (1) bearing hybridization to obtain compatibility with engine structure, and (2) reservoir modifications of separator/land areas to achieve reduced friction, increased damping and accelerated heat dissipation. The innovations of phase I, e.g., The integration of complex molybdate solid lubricant and critical bearing surfaces susceptible to rolling/sliding contact are also essential to the phase II effort. Full scale bearing tests will also be conducted to evaluate bearing performance life and assess dimensional changes and condition of the lubricant-bearing system after exposure to the severe operating conditions.