At the same time that these two bearing surfaces were being developed, highly cross linked polyethylene plastic liners were also developed.
Full-film conditions are when the bearing's load is carried solely by a film of fluid lubricant and there is no contact between the two bearing surfaces.
Brown's design embodied his effort to keep the two bearing surfaces of an axle, fixed and moving, apart.
This arrangement is usually more difficult to manufacture and service because two bearing surfaces or inserted sleeves complicate the design.
No interference fit is used in any instance and the pin 'floats' entirely on bearing surfaces.
They also offer more distance between the two bearing surfaces, which contributes to stiffness while allowing lighter components.
In practice, when bearing surfaces are pressed together, the fluid outflow is constricted.
This acidic build-up in the lubricating oil causes slow but ultimately damaging wear to bearing surfaces.
A preloaded bearing uses a spring or other compressive force to maintain bearing surfaces in contact despite reversal of direction.
Another application is thrust bearing surfaces of some production crankshafts.