What are the commonly used materials for oil seals?

Common materials for oil seals are: nitrile rubber, fluorine rubber, silicone rubber, acrylate rubber, polyurethane, PTFE, etc.

Nitrile rubber (NBR)
It has good heat resistance and wear resistance, and is resistant to various lubricating oils, greases, oil and gas mixtures, etc., and is suitable for temperatures ranging from -30 to 120 degrees Celsius, but it cannot be used in phosphate ester hydraulic oils and gear oils containing extreme pressure additives. It is stable in gasoline and low aniline point mineral oil.

Polyacrylate Rubber (ACM)
Excellent oil resistance, heat resistance, wear resistance, ozone resistance, UV radiation resistance, especially resistant to extreme pressure fluids containing lubricating oil, gear oil, motor oil, motor oil, petroleum hydraulic oil, etc., suitable for -30~150 degrees Celsius scope work.

Fluororubber
Aging resistance, heat resistance, oil resistance, suitable for almost all lubricating oil, fuel oil, gasoline, not easy to harden in oil containing extreme pressure additives, but poor cold resistance, high temperature wear resistance, large permanent compression deformation, suitable for At temperature -20~250 degrees Celsius.

Silicone Rubber
With outstanding high and low temperature resistance, it can be used for a long time at 150 degrees Celsius without performance changes; it can be used continuously for 10,000 hours at 200 degrees Celsius, and can maintain its unique use flexibility and ozone resistance and resistance in the working temperature range of -70~260 degrees Celsius. weather and other advantages.

Teflon
It has outstanding chemical stability, thermal stability, friction reduction and self-lubrication, and its cracking temperature is above 400. Therefore, it can work normally in the temperature range of -200~300 degrees Celsius. Excellent corrosion resistance to chemicals, solvents, oxyhydroxides and acids, except free fluorine and alkali metals.

Nitrile rubber and fluororubber materials are widely used oil seals. The former has low cost, but the temperature resistance and sealing performance are significantly improved, but the cost is high, and it still has some bad commonalities of ordinary rubber materials, such as poor wear resistance. , short service life, particularly sensitive to the eccentric response of the shaft, etc., leakage is still relatively common. PTFE oil seal is a product with high technical content, and it is the direction of oil seal development in the future.

When selecting the material of the oil seal, the compatibility of the material to the working medium, the adaptability to the working temperature range and the ability of the lip to follow the rotating shaft at high speed must be considered. Generally, when the oil seal is working, the temperature of its lip is 20~50℃ higher than the temperature of the working medium, so it should be paid attention to when selecting the oil seal material. The working range of the oil seal is related to the material used for the oil seal: -40~120℃ when the material is nitrile rubber (NBR), -30~180℃ for acrylic rubber (ACM), and -25~300℃ for fluorine rubber (FPM).