The correct selection of lubricating materials is the key to do a good job of equipment lubrication. The selection of lubricating materials should be reasonable according to the motion properties of friction pairs, the material composed of friction pairs, the working load, the working temperature, the matching gap, the lubrication method and the lubrication device. Lubrication materials are classified according to the use of the occasion. To firmly grasp the specifications, grades, performance and scope of application of various lubricating materials, correct selection.
1. General principles of selection
(1) According to the load size of the friction pair. The load is large, the lubricating oil viscosity should be large; The penetration of grease cone should be small. The adhesion and extreme pressure properties of lubricant should also be considered for low speed heavy load friction pair in boundary lubrication state.
(2) According to the motion speed of the friction pair. For the friction pair with high speed and light load, the lubricating oil with low viscosity or the grease with large cone penetration should be selected. Considering the role of centrifugal force, the rolling bearing should choose a lubricating oil with larger viscosity or a grease with smaller coning degree within the permissible range of temperature rise. For low-speed heavy load friction pairs, lubricants with larger viscosity or greases with smaller coning degree should also be selected, and lubricating materials containing oil additives and extreme pressure additives should be used as far as possible.
(3) According to the manufacturing accuracy of the friction pair. For friction pairs with high precision and small clearance, lubricating oil with small viscosity or grease with large taper should be selected. For gear drives and wire ropes with low accuracy, lubricants with larger viscosity or greases with smaller cone penetration should be selected.
(4) According to the material of the friction pair. The material hardness of the friction pair is low, should choose the viscosity of large, oily lubricating oil or a small coning degree of grease, the material hardness of the friction pair is high, should choose a small viscosity of the oil or a large coning degree of grease.
(5) According to the position, direction and working state of the friction pair. For working and friction pairs in vertical and non-horizontal directions, lubricating oil with higher viscosity should be selected, and lubricating grease should be selected if necessary. For parts that are not easy to refuel for a long time, use grease as much as possible.
(6) According to the working environment and working temperature. Machinery working in water or wet environment should be selected with good oil, rust prevention and good anti-emulsification performance of lubricating oil or grease. The working temperature is high, and the lubricating oil with high flash point, high viscosity, good oxidation stability and high temperature resistance or the lubricating grease with small cone penetration, high drop point and high temperature resistance should be selected. Low working temperature should be selected low pour point, small viscosity of water-free lubricating oil or cone penetration, low temperature resistance and grease. Large temperature changes should be selected with large viscosity index, low pour point of the lubricating oil or a wide range of temperature applicable grease. The machinery working in the working environment with corrosive media should choose lubricating materials with good corrosion and rust resistance. The chemical fertilizer industry and the machinery working in the presence of ammonia gas should use lubricating oil with good ammonia resistance. Food processing machinery should be used harmless to the human body suitable for food machinery lubrication lubricants and greases.
(7) According to the lubrication device selection of wear. The oil holes and oil nozzles of artificial oil injection should use lubricating oil with appropriate viscosity; The lubricating parts of oil line and felt oil absorption should be selected with less viscosity. The thin oil circulation lubrication system should choose the lubricating oil with low viscosity and good oxidation stability. Centralized dry oil lubrication system should choose grease with large cone penetration.
2. Selection of lubricating materials for common friction pairs and equipment
The operation and maintenance instructions of various mechanical equipment recommend suitable lubricating materials. In principle, it should be used according to the required varieties and grades. In order to solve the problem of domestic and temporary lack of substitution of oil for oral equipment and improve the lubrication effect, it is necessary to combine the nature of the original lubricating materials and the requirements of equipment lubrication, and select materials with equivalent or better performance.
