Study On Sealing Performance And Tribological Characteristics Of Surface Textured Rotary Oil Seals

The rotary oil seal is widely used in rotating machinery because of its simple structure,convenient installation and stable sealing performance,which plays the role of external dustproof and internal leakage prevention.The development of the equipment manufacturing industry requires a rotating oil seal under the conditions of grease lubrication and oil lubrication to have lower friction torque and friction temperature rise.In order to meet the above requirements,In this paper,the theoretical and experimental research on the rotating oil seal is carried out,the rectangular micro-texture with inclined feature is introduced on the surface of the rotating shaft,and the sealing performance and friction characteristics of the textured rotating oil seal are studied systematically.Based on the two-dimensional axisymmetric finite element model of rotating oil seal,the effect of interference and medium pressure on the static contact characteristics of the oil seal is analyzed,and numerical simulation of the temperature field of the seal was carried out.The results show that the contact pressure generated by the interference contact is the main source of the total contact pressure when there is no pressure difference.The ratio of the small interference is up to 90%,and the proportion is gradually decreased with the increase of the interference.The proportion of spring is gradually increasing;When there is a pressure drop,the medium pressure is the main source of total contact pressure,and its proportion increases with the increase of the medium pressure.The interference and the proportion of the spring are gradually decline.The temperature field simulation shows that the temperature difference between the two sides of the friction interface is not large,the temperature gradient of the lip contact area is large,and the axial position is equidistant from the center of the lip,and the air side axis temperature is greater than the medium side axis temperature.A rotary oil seal sealing performance test platform was built to realize on-line measurement of friction torque,interface temperature and reverse pumping rate.For the two types of oil seals of common type and pressure type,the sealing performance and tribological properties of the surface textured rotary oil seal under dry friction,grease lubrication and oil lubrication were tested.The results show that under the dry friction state,the friction torque and contact interface temperature of the common oil seal/texture shaft are larger than the smooth one,and the texture has a friction increasing effect;Under the condition of grease lubrication,the frictional torque of the textured shaft is reduced by 11%-45% compared with the smooth one,and the temperature under the lip can be reduced by 7%-22%.Under oil lubrication conditions,the reverse pumping rate of the texture shaft can reach 10 times of the smooth one for ordinary oil seals,both the friction torque and the lip temperature are larger than the smooth shaft,indicating that the texture is not conducive to improving sealing performance and friction characteristics.For pressure-resistant oil seals,the friction torque of the textured shaft can be 34% higher than that of the smooth shaft at low speeds.At medium and high speeds,the frictional torque of the textured shaft can be reduced by 15%-25% compared with the smooth one,and the temperature under the lip can be reduced by 10%-14%.The performance advantage of surface texture is obvious.The research results of the paper provide an effective method for prolonging the service life of oil seals and improving the sealing performance of oil seals,which provides a reference for designers to select and optimize micro-texture design.