Correct option is D
Anti-friction bearings are designed to reduce friction between moving parts using rolling elements (balls or rollers). They typically include ball bearings and roller bearings, which operate with minimal friction compared to sliding contact bearings.
Among the given options:
· Double-row ball bearings, needle roller bearings, and taper roller bearings are all types of anti-friction bearings as they use rolling elements.
· Thrust bearings, however, can be of different types, including fluid film thrust bearings, which work on hydrodynamic or hydrostatic lubrication principles, making them not purely anti-friction bearings.
Although some thrust bearings (e.g., thrust ball bearings and thrust roller bearings) use rolling elements, other thrust bearings (such as fluid film thrust bearings and plain thrust bearings) rely on a lubricant film rather than rolling elements, leading to higher friction compared to anti-friction bearings.
