The rubber ring is compressed and elastically deformed to achieve the sealing effect. The elastic deformation force increases with the increase in compression. The excessive pressure between the friction pairs affects the thickness of the lubricating film and makes it smaller, which makes the sealing surface lacking. The oil is insufficiently lubricated, the friction force becomes large, and the temperature rise is too high, which causes the friction pair to sinter and lead to scrap. In addition, the elastic deformation of the rubber ring is too large, which will accelerate the plastic deformation and cause the rubber material to accelerate aging. Regarding the important influence, the materials generally used now include nitrile rubber, hydrogenated nitrile rubber, silicone rubber, fluororubber, etc.