Study On Effect Factors Of Reciprocating Lip Seals’ Performance

The pumping effect occurs when reciprocating lip seals working because of specialpressure distribution in the sealing area. In the sealing region, the flow of oil is largerduring the instroke because the oil film is thicker than the outstroke, therefore theleaked fluid during the outstroke will be pumped back during the instroke. In order tofigure out how the parameters such as hardness of seal material, the interference fit orthe reciprocating speed of the rod affect the pumping effect, a finite element model ofreciprocating lip seals was built. Mechanical analysis has been done based on the modeland the pressure distribution in the sealing zone was obtained. The pumping rate wascalculated by the function which derived from Reynolds function, and the effect of theparameters on the pumping rate was analyzed.During the operation of the seal, heat will be generated because of the frictionbetween the seal and the rod which can lead to high temperature in the lip. On one hand,high temperature will accelerate rubber aging and wear, on the other hand, hightemperature of the oil will affect the pumping rate. The temperature of the lip is affectedby the heat and temperature of the oil, in order to figure out the relationship between thelip temperature and the heat, a finite steady temperature field on the seal was built.The result shows that, as the hardness of the material increase, the contact widthremains the same, the maximum pressure of the contact area, axial force, both pressuregradient of the instroke and outstroke increase; the thick of oil film and pumping ratedecrease while the heat generation increase. When the interference fit increase, thewidth of the contact area, maximum of the pressure, axial force and the heat generationincrease.