Pad Preload (Tilting Pad Bearings)
A titling pad bearing parameter that quantifies how the radii of the pads differ from the journal radius. Preload is defined by the following formula:
where Mp is the bearing preload; Cb is the radial bearing clearance; and Cp is the radial pad clearance.
A preload of zero means there is a constant clearance around all pads, while a positive pad preload helps develop a converging oil film. Increasing the pad preload is a common means of eliminating pad flutter, even under light and nonload conditions. Negative preloads are generally avoided to prevent divergent oil films and pad flutter.