Linear bearing is a kind of linear motion system, which is used for the combination of linear stroke and cylindrical shaft. Because the bearing ball contacts with the bearing jacket point and the steel ball rolls with the minimum friction resistance, the linear bearing has less friction and is relatively stable, and does not change with the bearing speed, so it can achieve a smooth linear motion with high sensitivity and accuracy. The consumption of linear bearings also has its limitations. The main reason is that the impact load capacity of bearings is poor, and the bearing capacity is also poor. Secondly, the vibration and noise of linear bearings are larger when they move at high speed. The automatic selection of linear bearings is included. Linear bearings are widely used in sliding parts of precision machine tools, textile machinery, food packaging machinery, printing machinery and other industrial machinery. 
Because the bearing ball contacts with the bearing point, the use load is small. The steel ball rotates with minimal friction resistance, so that it can achieve high precision and smooth motion.
Plastic linear bearing is a kind of linear motion system with self-lubrication characteristics. The biggest difference between plastic linear bearing and metal linear bearing is that the metal linear bearing is rolling friction, and the point contact between bearing and cylindrical shaft is point contact, so it is suitable for low load and high speed motion; while plastic linear bearing is sliding friction, and the surface contact between bearing and cylindrical shaft is surface contact, so it is suitable for high load, medium and low speed motion. 。