Plain bearings are simple mechanical components that allow for smooth motion between two surfaces. They consist of a shaft that rotates within a cylindrical sleeve, often made of materials like bronze, plastic, or steel. These bearings reduce friction and wear, enabling efficient movement in machines and vehicles. Unlike ball bearings or roller bearings, plain bearings do not have rolling elements. Instead, they rely on a lubricating film to minimize contact between the surfaces. This design makes them suitable for various applications, including automotive engines and industrial machinery, where durability and low maintenance are essential.