What is the primary function of a thrust bearing in a main engine?

The primary function of a thrust bearing in a main engine is to support vertical forces, which refers to the axial loads that are generated due to the rotation of the shaft and other dynamics within the engine. Thrust bearings are designed specifically to handle these axial loads, ensuring that the shaft remains properly positioned and can rotate smoothly. This is crucial for the overall functioning of the engine, as it allows for efficient power transmission and helps maintain the engine's structural integrity during operation.

While minimizing friction, allowing axial movement, and applying pressure to the rotor can be functions associated with different types of bearings or components in a mechanical system, the unique purpose of thrust bearings is to support the vertical forces exerted as the engine operates, which is why this answer is accurate.