Shortcomings of bearing grease
Grease has many advantages in bearing use, but it also has the following disadvantages:
(1) The grease is semi-solid and does not flow at normal temperature, so it is difficult to grease or change the grease on the friction parts, and the cleaning of the bearings is not very convenient.
(2) It is difficult to separate moisture, dust, and abrasive debris. In the case of lubricating oil, the impurities generally sink to the lower part or are easily removed by the oil filter.
(3) The stirring resistance is large, so the heat generation is large and the cooling effect is poor. However, it should be noted here that this has a close relationship with the lubrication method. If the lubricating oil is lubricated with a fully immersed (or semi-immersed) oil bath, the grease will consume less power than the oil. For example, the British Journal of Friction and Lubrication reported in 1973, 6th issue: With a rolling bearing with a diameter of 100, the rotational speed is 1500r/min, and it is lubricated with grease. There are many examples of energy consumption in China, such as the fire-resistant tunnel of the Chongqing Iron and Steel Company Refractory Plant. The motor power of the kiln induced draft fan is grease compared to the lubricating oil using N68, and the bearing temperature is 4~6 °C lower.
(4) Not suitable for high speed. In general, the normal mineral oil grease is only allowed to use the transfer speed to become the DN value (bearing inner diameter mm × rotation speed r / min) is less than 300,000 mm · r / min. With the development of grease technology, synthetic lubrication can be used with a DN value of 500,000 to 600,000 or even 1 million. The fastest example of the use of grease is the launch bearing of the high-altitude unmanned jet reconnaissance aircraft (reported by Japan's "Defense Technology" in 1984), which is lubricated with grease in order to reduce the weight of the aircraft. Bearing inner diameter ф25mm, temperature 200 °C, speed 4600r / min, DN value is 1.8 million, with synthetic oil grease to meet the life expectancy of 30min
(5) The stirring resistance is large, so the heat generation is large and the cooling effect is poor.
(1) The grease is semi-solid and does not flow at normal temperature, so it is difficult to grease or change the grease on the friction parts, and the cleaning of the bearings is not very convenient.
(2) It is difficult to separate moisture, dust, and abrasive debris. In the case of lubricating oil, the impurities generally sink to the lower part or are easily removed by the oil filter.
(3) The stirring resistance is large, so the heat generation is large and the cooling effect is poor. However, it should be noted here that this has a close relationship with the lubrication method. If the lubricating oil is lubricated with a fully immersed (or semi-immersed) oil bath, the grease will consume less power than the oil. For example, the British Journal of Friction and Lubrication reported in 1973, 6th issue: With a rolling bearing with a diameter of 100, the rotational speed is 1500r/min, and it is lubricated with grease. There are many examples of energy consumption in China, such as the fire-resistant tunnel of the Chongqing Iron and Steel Company Refractory Plant. The motor power of the kiln induced draft fan is grease compared to the lubricating oil using N68, and the bearing temperature is 4~6 °C lower.
(4) Not suitable for high speed. In general, the normal mineral oil grease is only allowed to use the transfer speed to become the DN value (bearing inner diameter mm × rotation speed r / min) is less than 300,000 mm · r / min. With the development of grease technology, synthetic lubrication can be used with a DN value of 500,000 to 600,000 or even 1 million. The fastest example of the use of grease is the launch bearing of the high-altitude unmanned jet reconnaissance aircraft (reported by Japan's "Defense Technology" in 1984), which is lubricated with grease in order to reduce the weight of the aircraft. Bearing inner diameter ф25mm, temperature 200 °C, speed 4600r / min, DN value is 1.8 million, with synthetic oil grease to meet the life expectancy of 30min
(5) The stirring resistance is large, so the heat generation is large and the cooling effect is poor.
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