The lubrication principal used by the Kingsbury thrust bearing is _________.

Correct Answer: Option C — wedge-shaped oil film

Kingsbury thrust bearings utilize the hydrodynamic principle of a wedge-shaped oil film. As the thrust collar rotates, oil is dragged into the space between the tilting pads and the collar. This converging geometry creates a high-pressure wedge that supports the axial load, preventing metal-to-metal contact during operation.