1. Oil cup drip lubrication
A lubrication method of lubricating bearings by dripping oil through the fuel saving port in the oil cup The advantages of oil cup drip lubrication are simple structure, convenient use, and fuel efficiency. Moreover, the fuel supply can be adjusted through the fuel saving port, and the recommended oil drop rate is usually one drop every 3-8 seconds, as excessive oil can cause an increase in bearing temperature. The disadvantage is that there is a certain requirement for the viscosity of the lubricating oil, and high viscosity lubricating oil cannot be used, without heat dissipation function. Oil cup drip lubrication is suitable for low-speed, light load, and low-temperature working environments.
2. Oil bath (immersion in oil) lubrication
A lubrication method in which the bearing part is immersed in lubricating oil and the oil is carried into other parts of the bearing after the bearing operates. Oil bath lubrication is one of the most common and convenient lubrication methods.
Considering the stirring loss and temperature rise during oil bath lubrication, there should be certain limitations on the height at which the bearing part penetrates into the lubricating oil for horizontal shafts. Generally, the oil level is controlled near the center of the rolling element at the bottom 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 enter the bearing and damage it. Oil bath (immersion) is generally suitable for low-speed or medium speed applications and is more commonly used on low-speed bearings
Experience: Separable reinforcement 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 elements. If the temperature of the bearings in the oil bath system is relatively high, the dripping method, splashing or circulating oil system can be used instead.
3. Splash lubrication
A lubrication method in which oil splashes into bearings through other moving 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 from the oil tank into the bearing and damage the bearing.
In splash lubrication, oil splashes onto the bearing through the rotating body (impeller or "oil slinger") mounted on the shaft, and the bearing is not submerged in oil.
Experience: In gearboxes, gears and bearings often share the same oil tank with gears that serve as oil slingers. Due to the possible differences in viscosity between gear oil and bearing requirements, as well as the presence of wear particles from gears in the oil, separable lubrication systems or methods 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, transported to the parts of the bearing that need lubrication, and then returned to the oil tank through the return port, filtered and reused.
Circulating oil provides sufficient lubrication, easy control of oil supply, and strong heat dissipation and impurity removal capabilities. Circulating oil lubrication is suitable for applications aimed at heat dissipation or impurity removal, as well as high-speed, high-temperature, and heavy-duty situations, with high reliability in use. Circulating oil lubrication is an ideal lubrication method. But it requires an independent fuel supply system, and the manufacturing cost is relatively high. The oil supply system consists of an oil pump, cooler, filter, oil tank, oil pipeline, 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 part of the bearing.
Oil mist lubrication has low mixing loss and temperature rise, is fuel-efficient, and contains fewer impurities in the oil. In addition, the airflow generated during oil mist spraying has a certain cooling effect, which can effectively prevent impurities from entering or being discharged. However, the cost of lubrication equipment is relatively high, and there are certain requirements for the viscosity of the oil used. Generally, it should not exceed 340mm 2/s, otherwise the atomization effect will not be achieved. In addition, if the seal is not tight during lubrication, some oil mist may dissipate into the air and pollute the environment. If necessary, an oil and 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 spray lubricating oil into the bearing and lubricate it. When the bearing is running at high speed, the rolling elements and the cage also rotate at a considerable speed, forming air vortices around the bearing. If a general lubrication method is used, the lubricating oil is not easy to reach the lubrication part. On the other hand, due to the centrifugal force generated at high speeds, it is difficult for lubricating oil to remain in the lubrication area. To ensure sufficient and not excessive lubricating oil supply to high-speed running bearings, lubricating oil must be forcibly sprayed into the bearing from one end for lubrication, and then re flowed 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 injection 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 injected directly into the bearings.
7. Oil air 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 supplies it to the bearings. This method is suitable for high-speed applications, such as machine tools, and is generally less used in the refining and chemical industries.

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