What type of bearing relies on rollers to reduce rolling friction?

• A. Plain bearing
• B. Friction bearing
• C. Cylindrical bearing
• D. Anti-friction bearing

Answer: (D)

The choice of anti-friction bearing as the correct answer arises from its design, which incorporates rolling elements, such as balls or rollers, to facilitate movement. This rolling mechanism significantly reduces friction compared to other types of bearings that rely on sliding surfaces. In an anti-friction bearing, the rolling elements rotate within the inner and outer rings of the bearing, allowing for smoother motion and decreased wear over time.

In contrast, plain bearings and friction bearings generally operate by sliding against each other, which results in higher friction levels and increased heat generation. While cylindrical bearings are often classified as a type of anti-friction bearing due to their roller elements, the term "anti-friction bearing" specifically refers to any bearing that uses rolling elements, making it the broad and accurate choice in this context. Thus, the fundamental mechanism of rolling versus sliding is crucial to understanding why anti-friction bearing is the appropriate response.