Sliding bearings worked at sliding friction. Sliding bearings work smoothly, reliable, without noise. Under the liquid lubrication, the sliding surface is separated by oil, the surface without direct contact, this will reduce the friction loss and surface wearing, and the oil film also have a certain vibration absorption capacity, but the starting frictional resistance is large.
Sliding bearings always applied in high-speed, heavy-load, high precision or intermittent working conditions. The friction of sliding bearings depends on the sliding surface material, the working surface of sliding bearings are self-lubricating. 
 According to the material, sliding bearings are named metal sliding bearings and non-metal sliding bearings, non-metal are mainly plastic bearings, metal sliding bearings are most used three-layer composite bearings, the carbon steel as basis plate, sintering a layer of copper powder and a layer 0.03mm PTFE, the copper powder bond strength between steel and PTFE, and play a role in load and lubrication.