ABSTRACT
Hydrodynamic lubrication develops a ¨uid Ÿlm due to shearing action in the lubricant caused by relative motion between two surfaces. In contrast, hydrostatic lubrication achieves a ¨uid Ÿlm via the supply of lubricant under pressure from an external source. ˜ere is no physical contact during start-up and shutdown. Hydrostatic bearings are typically used when an application requires full Ÿlm lubrication and is unable to develop an adequate Ÿlm hydrodynamically. Since hydrostatic lubrication does not require relative motion between the bearing surfaces to develop a ¨uid Ÿlm pressure to support a load, this makes hydrostatic bearings particularly well suited to very low speed, reversing, or even zero speed operation. Other advantages of hydrostatic bearings over other bearing types include low friction, high stiµness, long life, and high load capacity. ˜e main disadvantage of hydrostatic bearings is the cost and complexity of an external pressurized lubricant supply system.
