Which type of bearing uses the shaft as the inner race?

• A. Ball bearings
• B. Needle bearings
• C. Roller bearings
• D. Thrust bearings

Answer: (B)

Needle bearings are designed to use the shaft as the inner race, which is a key characteristic that distinguishes them from other types of bearings. These bearings consist of slender, elongated rollers (needles) that provide a large surface area for load distribution while minimizing friction. The design allows them to support heavy radial loads in a compact space, making them ideal for applications where space is limited.

In contrast, ball bearings, roller bearings, and thrust bearings typically have an inner race that is separate from the shaft. Ball bearings use spherical elements to reduce friction, roller bearings utilize cylindrical rollers, and thrust bearings are tailored for axial loads with raceways specifically designed for that purpose. Each of these bearing types relies on a dedicated inner race for proper functioning, emphasizing why needle bearings stand out in this context.