A roller bearing is a type of mechanical component that reduces friction between moving parts. It consists of cylindrical rollers placed between two rings, known as the inner and outer races. These rollers help support loads and allow for smooth rotation or linear movement in machines and vehicles. Roller bearings are commonly used in various applications, including automobiles, industrial machinery, and electric motors. They come in different designs, such as tapered, cylindrical, and spherical, each suited for specific load and speed requirements. By minimizing friction, roller bearings enhance efficiency and prolong the lifespan of equipment.