What is the main purpose of bearings?

• A. Support load
• B. Transmit torque
• C. Reduce friction
• D. Store energy

Answer: (C)

Reducing friction between moving parts is the essential role of bearings. When two surfaces rub together, they create resistance, wear, and heat. Bearings provide a smooth interface between components—either through rolling elements like balls or rollers or through a lubricated sliding surface—so the shaft can rotate with much less resistance. This friction reduction enables smoother motion, higher speeds, and longer life for the machinery.

Bearings also support loads and help keep the shaft properly positioned, so they do carry radial and/or axial loads. However, the primary benefit driving their design is the drastic decrease in friction, not energy storage or other functions.