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PART.1
Low temperature bearings are not the bearings that run stably in high temperature environment corresponding to high temperature bearings, but refer to the design of special materials and structures to reduce the friction coefficient, so as to reduce friction heating, so that the bearings remain low temperature in long-term operation.
PART.2
Bearings whose operating temperature is below -60℃ are low-temperature bearings. Mainly used in all kinds of liquid pump, such as liquefied natural gas pump, liquid nitrogen (hydrogen, oxygen) pump, butane pump, rocket missile liquid pump, spacecraft and so on.
Bearing operating temperature is an important index of the world bearing brand
The operating temperature of low-temperature bearings reflects the material technology and processing level of bearing processing. Its measurement is mainly based on the temperature difference between the bearing outer ring and the injection cooling oil during operation.
Lower operating temperature means longer service life and higher performance of bearings. The world famous bearing manufacturers, relying on their own advantages, strive to achieve comparative advantages of low-temperature bearings in many fields. Take Timken self-alting roller bearings as an example. After rigorous testing, the company’s operating temperature of such products is lower than similar products in the market, about 15.5 degrees Celsius, while other internationally renowned brands are above 19 degrees Celsius.
For the phenomenon of bearing stuck at low temperature, the external factor is the change of temperature, and the internal factor is the different thermal expansion coefficient of shaft, frame and material. When the temperature range is large, the shrinkage rate of different materials is different, resulting in the gap becoming smaller and stuck. Therefore, for a wide range of equipment, including equipment used at low temperatures, it is necessary to calculate the expansion coefficient of the material, while trying to use materials with similar expansion coefficient, the effect will be better.
In addition, in the structural design, try to avoid the use of a tapered roller bearing structure at both ends of the shaft. With this structure, the longer the distance between the two bearings, the more likely it is to get stuck. If one end of the shaft is installed with a pair of conical bearings, the axial movement of the shaft is constrained as the positioning of the shaft, and the other end of the shaft is used with the rolling bearing to limit the radial force only. In the axial direction, the axial movement can be moved within a certain range with the axial temperature.
Low temperature bearings are commonly used in stainless steel bearing steel 9Cr18, 9Cr18Mo manufacturing, also can choose beryllium bronze, ceramic and other materials manufacturing; Operating temperature Extremely low temperature conditions (limit temperature -253℃) : operating limit temperature requirements at -253℃, can choose 6Cr14Mo material but must be used in a vacuum environment.
Note: In the use of low-temperature bearings, attention should be paid to burns caused by poor lubrication, so attention should be paid to the selection of appropriate lubricants.
Post time: Apr-20-2022