Research On Pumping Mechanism And Heat Dissipation Mechanism Of Rotary Lip Seal

Currently the design of rotary lip seal in our country mainly depends on thetraditional way of experience designing and rough macro analysis and the performanceof oil seal is unforeseen. We can know whether it is qualified only by experiment but itis both time-consuming and laborious. Many people have studied the oil seal, but theymerely care about the sealing mechanism and heat production which are affected by theimportant parameters of the oil. In this article, a2-D axisymmetric finite element modelis established using the finite element software for the rotary lip seal. The influence ofimportant parameters on the contact width and the contact pressure distribution isobtained. Moreover, based on results of the finite element analysis, pumping rate andthe amount of heat generated are estimated using a theoretical analysis method. Basedon the analysis above, a2-D axisymmetric model of the lip of the oil seal and the shaftis established using CFD software. The influence of the important parameters ontemperature distribution of the lip is gotten.The results of finite element software and theory analysis show that, the maximumamount of Cauchy stress and contact stress are located at the tip of the lip seal and theCauchy stress and contact stress decrease quickly from the tip of the seal to the air sideand oil side. With the increase of the interface of the shaft and seal the contact width,pumping rate and heat production increase while the maximum amount of contact stressincreases at first and then decreases. With the different spring stiffness coefficient, thecontact pressure distributions are similar and the inner diameter is decrease with theincrease of spring stiffness. With the increase of spring stiffness coefficient, the amountof heat increases quickly, whereas, the pumping rate rarely changes. With the increaseof the distance along the shaft between the center of the spring and the tip of oil seal, thecontact width and the amount of heat generation decrease, while the pumping rateincreases. The pumping rate and contact width decreases whereas the heat generationincreases slowly with the increase of contact surface angel of the air of the oil seal. Asthe shaft speed increases, the amount of heat and pumping rate increase rapidly.The results of numerical simulation of CFD show that, the maximum temperatureis concentrated in the lip of the oil seal and the temperature decreases not only from thelip to the center of the shaft but also from the lip to the oil and air side of the oil seal.The temperature of the shaft is higher than the oil and the temperature of the air side is higher than the oil side. With the same speed of the shaft， the maximum temperature ofthe lip increases with the increase of the interference between the shaft and seal, springstiffness coefficient, whereas, the maximum temperature of the lip decreases slowlywith the increase of the angle of air side. The maximum temperature of the lip increaseslinearly with the increase of shaft speed.