Sliding bearing is used to work under sliding friction. The sliding bearing is stable, reliable and noise free. Under the condition of liquid lubrication, the sliding surface is separated by the lubricating oil without direct contact, and the friction loss and surface wear can be greatly reduced, and the oil film also has a certain absorption capacity. But the starting friction resistance is larger. The part supported by the shaft is called the journal, and the part matching the journal is called the bearing bush. Generally used in relatively small mechanical equipment, high speed, such as motor, gear box and so on, the application of sliding bearings in low speed heavy load conditions, or maintenance and injection of lubricating oil difficult operation parts, such as the propulsion shaft of the ship.