TABLE 1. Types of Thrust bearings [Applied Tribology- Bearing Design and Lubrication] V. TILTING PAD THRUST BEARINGS Tilting Pad Thrust Bearings are designed to transfer high axial loads from rotating shafts with minimum power
loss, while simplifying installation and maintenance. Here the load carrying surfaces are completely separated
by an oil film, eliminating the risk of surface wear as long as a film of sufficient thickness is maintained. In
order to attain hydrodynamic (full-film) lubrication, the pad must sit at an angle to the oil flow so that a
converging ―wedge‖ is produced (refer figure 2a). Each bearing consists of a series of pads supported in a
carrier ring; each pad is free to tilt so that it creates a self-sustaining hydrodynamic film. The carrier ring may be
in one piece or in halves with various location arrangements. They are used increasingly in marine drives,
turbines, compressors and pumps. This flow constriction acts as a bottleneck, effectively slowing down the flow
rate across the pad from the inlet edge towards the trailing edge. The gradually reducing available volume in the
gap leads to a pressure build-up in the oil film giving rise to a force which ―lifts‖ the shaft. (Refer figure 2b).
Another contributory effect is the viscous flow resistance which prevents the oil from running out of the gap
instantaneously as the pressure increases.
Fig.2 a) A cut-away of a tilting pad
Fig.2 b) Pressure distribution within the thrust bearing and runner arrangement bearing
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IJARSE, Vol. No.4, Special Issue (01), March 2015 ISSN-2319-8354(E)
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