Rolling bearing is a kind of mechanical element which is widely used in mechanical transmission. It is generally composed of rolling elements, inner ring, outer ring and cage. When the bearing is working, the inner ring (outer ring) often rotates while the other ring remains fixed, the rolling body rotates and revolves along the raceway, and the cage moves in a circular motion with the revolution of the rolling body. The movement conditions are mainly rolling and sliding friction. Due to the friction will cause local thermal deformation, accelerate the wear of the surface of the parts, resulting in an increase in the running error and even the main shaft being scrapped. In order to ensure the safe and reliable operation of the bearing, in order to minimize friction and wear when the bearing is working, and avoid the failure caused by pitting corrosion on the bearing surface, the bearing must be lubricated. Normal lubrication can significantly improve the fatigue life and friction, wear, temperature and vibration of rolling bearings. Analysis of the causes of bearing damage shows that about 40% of the bearing damage is related to poor lubrication. The content of the lubrication design of rolling bearing mainly includes: the determination of the reasonable lubrication method, the correct selection of the lubricant, the quantitative calculation of the amount of the lubricant and the determination of the oil change interval. Rolling bearing lubrication can generally be divided into three categories: oil lubrication, grease lubrication and solid lubrication according to the type of lubricant used. The three lubrication methods of rolling bearings and their characteristics and applications are discussed in detail below: 1. Oil lubrication When rolling bearings work under high temperature and high speed conditions, oil lubrication must be used. Commonly used lubricating oils are mechanical oil, high-speed mechanical oil, turbine oil, compression bell-ting ⒈ 溲 饔 饔 bald push cylinder oil, etc. When lubricating oil is used, the viscosity of the lubricating oil is the premise for the formation of the lubricating oil film. In order to form a lubricating oil film of sufficient thickness between the raceway and the contact surface of the rolling elements, the viscosity of the oil should ensure that it does not lose its minimum viscosity at the working temperature. . Therefore, when selecting lubrication, the viscosity of the oil should ensure that it can provide sufficient lubrication for the bearing at operating temperature. Generally speaking, low-viscosity lubricating oil should be used when the bearing speed is high; when the bearing is under heavy load, higher-viscosity lubricating oil should be used. According to the different structure of the lubricating system used in oil lubrication, oil lubrication can be divided into the following categories: 1) Oil bath lubricating oil bath lubrication is one of the most commonly used and very simple lubrication methods, suitable for low and medium speed operation bearing. The lubricating oil is carried by the rotating bearing parts and lubricates the bearings before flowing back into the oil tank. When lubricating with this method, attention should be paid to the control of the oil quantity. The height of the oil level should be slightly lower than the center line of the rolling element of the lowermost bearing. Excessive oil quantity will cause excessive temperature rise and agitation, and insufficient oil quantity will cause the early stage of the bearing If it fails, it is recommended to check (maintain) the proper oil level with an oil level indicator. 2) Drip oil lubrication Drip oil lubrication is to use the weight of the lubricating oil to drip onto the friction pair drop by drop. A needle valve type oil filling cup is provided at the oil supply part. This lubrication method is mostly used on friction pairs that are small in number and easy to approach, such as the lubrication of machine tool guide rails, bearings, gears, chains and other parts. When the bearing parts need to supply lubricating oil quantitatively, drip oil lubrication can be used, and the amount of oil dripping is generally one drop every 38 seconds, because too much oil will cause the temperature rise of the bearing to increase. 3) Circulating oil lubrication When the bearing running speed is high, the bearing temperature rise will increase accordingly, resulting in the aging of the oil. The use of circulating oil lubrication can effectively prevent the occurrence of the above phenomenon. The lubricating oil is sent to the bearing parts through the oil pump, and an oil inlet is installed at one end of the bearing, and the lubricating oil after the lubricating oil is applied to the Mü bearing can be recycled after being filtered and cooled. Since the lubricating oil can take away a certain amount of heat during the circulation process, it can ensure that the bearing can always work at a lower temperature, so this method is suitable for bearing parts with high rotation speed. However, it should be noted that the oil outlet should be larger than the oil inlet so that there is no residual oil left in the bearing seat. 4) Oil injection lubrication When the bearing is running at high speed with low to medium load, the rolling elements and cage also rotate at a relatively high speed to form an air vortex around the bearing. In order to ensure that a sufficient amount of lubricating oil is supplied to the bearings running at high speed, the lubricating oil must be sprayed into the bearing from one end of the bearing and lubricated by the method of high pressure injection. After lubrication, the oil will flow back into the other end. In order to effectively lubricate the bearing, care should be taken that the position of the high-pressure nozzle is located between the inner ring and the center of the cage, the injection speed of the lubricating oil should not be lower than 15m/s, and the oil should be injected directly into the bearing.u200bu200b