1. Oil cup drip lubrication
A lubrication method that drips oil to the bearing through the oil saving port in the oil cup. The advantages of oil cup drip lubrication are simple structure, convenient use, and fuel efficiency. Moreover, the oil supply quantity can be adjusted by the oil saving port, and it is generally recommended to drop one drop every 3-8 seconds, as excessive oil quantity can cause an increase in bearing temperature rise. The disadvantage is that there are certain requirements for the viscosity of the lubricating oil, and lubricants with high viscosity cannot be used, and there is no heat dissipation function. Oil cup drip lubrication is suitable for low speed and light load working at low temperatures.
2. Oil bath (immersion) lubrication
A lubrication method in which the bearing is partially immersed in lubricating oil and the oil is introduced into other parts of the bearing after the bearing is running. Oil bath lubrication is one of the most commonly used and convenient lubrication methods.
Considering the stirring loss and temperature rise during oil bath lubrication, there should be a certain limit on the height of the bearing part invading the lubricating oil for the horizontal shaft. Generally, the oil level should be controlled near the center of the lowest rolling element of the bearing. Oil bath (immersion) lubrication provides sufficient lubrication, but the oil supply is difficult to adjust. If there is no filtering device in the oil tank, impurities can easily be brought into the bearing and damage the bearing. Oil bath (immersion) is generally suitable for low or medium speed applications, and is commonly used on low speed bearings
Experience: Detachable reinforcing ribs can be installed at the bottom of the bearing seat to reduce agitation and/or heat dissipation. The static oil level should be slightly lower than the center of the lowest rolling element of the bearing applied to the horizontal axis, and for the vertical axis, the static oil level should cover 50% -80% of the rolling element. If the temperature of the bearings in the oil bath system is relatively high, it can be changed to using a drip, splash, or circulating oil system.
3. Splash lubrication
A lubrication method that involves splashing oil into bearings through other operating parts. The splash lubrication oil supply is not easy to adjust, and the lubricating oil level should not be too high, otherwise it is easy to cause mixing loss and temperature rise, and it is also easy to bring impurities in the oil tank into the bearing to damage the bearing.
In splash lubrication, oil splashes onto the bearings through the rotating body (impeller or "oil throwing ring") installed on the shaft, and the bearings are not immersed in the oil.
Experience: In gearboxes, gears and bearings often share the same oil tank as the gear used as the oil throwing ring. Due to the fact that the viscosity of gear oil may differ from the requirements of bearings, and the oil contains wear particles from gears, a separable lubrication system or method can be used to improve bearing life.
4. Circulating oil lubrication
A lubrication method in which lubricating oil is sucked from the oil tank by an oil pump and transported to the parts of the bearing that require lubrication, then returned to the oil tank through the return port, filtered, and reused.
The circulating oil lubrication is sufficient, the oil supply quantity is easy to control, and the ability to dissipate heat and remove impurities is strong. Circulating oil lubrication is suitable for applications aimed at heat dissipation or impurity removal, as well as high-speed, high-temperature, and heavy-duty applications, with high reliability. Circulating oil lubrication is an ideal lubrication method. But it requires an independent oil supply system, and the manufacturing cost is relatively high. The oil supply system consists of oil pumps, coolers, filters, oil tanks, oil pipelines, etc. Circulating oil lubrication includes oil injection lubrication, forced lubrication and spray lubrication. They are classified from different perspectives.
5. Oil mist lubrication
A lubrication method in which lubricating oil is mixed with compressed air and a small amount of lubricating oil in an oil mist generator to form an oil mist, and then transported to the lubrication area of the bearing.
Oil mist lubrication has low stirring loss and temperature rise, is fuel-efficient, has fewer impurities in the oil, and the airflow generated during oil mist spraying has a certain cooling effect. It can also effectively prevent impurities from entering or discharging. However, the cost of lubrication devices is relatively high, and there are certain requirements for the viscosity of the oil used. Generally, it should not exceed 340mm2/s, otherwise the atomization effect will not be achieved. In addition, if the seal is not tight during lubrication, some oil mist may escape into the air and pollute the environment. If necessary, an oil gas separator should be used to collect the oil mist. Oil mist lubrication is suitable for high-speed applications.
6. Oil injection lubrication
A lubrication method that uses high-pressure injection to inject lubricating oil into the bearing and lubricate it. When the bearing runs at high speed, the rolling element and cage also rotate at a relatively high speed, forming air vortices around the bearing. If ordinary lubrication methods are used, the lubricating oil is not easy to reach the lubrication area. On the other hand, due to the centrifugal force generated at high speeds, it is difficult for the lubricating oil to remain in the lubrication area. To ensure sufficient but not excessive supply of lubricating oil to high-speed running bearings, it is necessary to forcefully spray lubricating oil into one end of the bearing for lubrication, and then re flow into the oil tank from the other end.
When designing the lubrication system, the position of the high-pressure nozzle should be located between the inner ring and the center of the cage, and the lubricating oil should be thrown out of the raceway through centrifugal action. In order to effectively lubricate bearings, the spraying speed of lubricating oil should not be less than 15m/s.
From the perspective of operating speed, oil injection lubrication is commonly used for bearings that operate at higher speeds under low or medium loads; From the direction of bearing force, oil injection lubrication is commonly used for bearings on vertical or inclined shafts, and lubricating oil is usually directly injected into the bearings.
7. Oil and gas lubrication
Oil air lubrication is usually suitable for situations where bearings operate at high speeds. The oil air lubrication system mixes a small amount of lubricating oil with a certain pressure of gas, and then supplies it to the bearings. This method is suitable for high-speed applications, such as machine tools, which are generally less commonly used in the refining and chemical industry.