In the liquid lubrication conditions, the sliding surfaces are separated from lubricating oil without direct contact, but also can greatly reduce the friction losses and wear surface, the film also has a certain vibration absorption ability. But the starting frictional resistance is large. Shaft is bearing part is called the journal, and the journal mating parts called bush. In order to improve the friction properties of the surface of the pad on the inner surface of the casting antifriction material layer is called the bearing bush. Bearings and bearing liner materials collectively known as the sliding bearing material. Common sliding bearing materials bearing alloy (also known as white metal or babbitt), cast iron, copper and aluminum alloy, powder metallurgy materials, plastics, rubber, hardwood and carbon - graphite, polytetrafluoroethylene (PTFE ), modified POM (POM), and the like. Bearing applications generally carried out at low speed heavy working conditions, maintenance or filling oil and difficult to operate the site.