A good oil seal is particular, in addition to size, its sealing performance must be considered. Dongsheng sealing ring tells you the factors that affect the sealing performance of the oil seal, including oil pressure, lip rubber performance, structural parameters, lip interference, R value (distance from the sealing ring lip plane to the spring groove center plane), lip waist thickness, lip waist length, medium temperature, oil seal shaft speed, etc. may affect the sealing performance of the oil seal! Let us first understand the degree of influence of the surface roughness of the sealing ring shaft that affects the sealing performance of the oil seal?

According to the oil film lubrication theory, there is a layer of lubricating oil film between the shaft and the lip of the sealing ring (oil seal), about 0.0025mm, which is only 0.0025mm greasy, thus avoiding the dry friction between the shaft and the lip. The shaft surface roughness is related to the existence state of greasiness. If the surface roughness of the shaft is too large or greater than Ra0.9μm, the convex peak of the shaft surface will pass through the oil film and contact the oil seal lip of the sealing ring, forming dry friction, causing the surface wear of the lip and thickening of the oil film under the lip, resulting in seal failure; If the surface roughness of the shaft is too small or less than Ra0.12μm, the contact part between the lip and the shaft will be adsorbed by the surface recess of the shaft, which will cause the oil extrusion and the oil film destruction, formation of dry friction, resulting in wear of the lip of the oil seal ring. In general, a shaft surface roughness Ra of 0.2 to 0.6 μm is preferable. In addition, the ovality, eccentricity and runout of the shaft also directly affect the sealing performance of the skeleton shaft lip oil seal ring.