Research On Sealing And Friction Characteristics Of O-seal Ring

O seal ring is the common sealing device for cylinder. The sealing performance and friction performance of cylinder play an important role in stable movement and precise control. The research on the O seal ring includes the reliability analysis, the choices of the structure parameters of the sealing ring, the distribution of contact stress and lubrication and friction characteristics and relevant theory research. In this paper, according to the unilateral constrained O sealing ring, the stress field and temperature field are analyzed and the mathematical model of grease lubrication and friction properties are built.The two-dimensional axisymmetric finite element model of the rubber O seal ring is established with the help of software ANSYS. By analyzing the laws of the compression and the driven cavity gas pressure on the contact stress and Von Mises stress, a conclusion can be obtained that O seal ring can achieve reliable static sealing when the compression is greater than 10% and the driving pressure is less than 0.5Mpa. When considering the relative sliding speed, the heat generation mechanisms by friction and mechanical hysteresis of rubber seal ring are analyzed. The influence of temperature on the sealing contact stress is considered, and the temperature field result files are extracted into the structural field and two times coupling are realized. The rise of contact zone temperature has little effect on the contact stress. The compression of O-ring has great influence on the performance of static sealing.The contact stress distribution of the finite element is regarded as the initial condition, and the mathematical model including Reynolds equation, film thickness equation, viscosity temperature pressure equation and load balance equation are established. In order to improve the convergence of the iteration, the numerical solution of the whole equation is solved by using the multi grid numerical integration method. Through the C programming language, the changes trend between the lubricant film thickness and the relative sliding speed are achieved. The simulation results show that the gas pressure has little effect on the film thickness, but the contact stress is greatly affected. The relative sliding velocity has the greatest influence on the film thickness, and has little effect on the contact stress distribution. The film thickness in the contact center area is between one and two microns, which can be fully lubricated.A sliding friction model between the sealing ring and cylinder in rough rigid surface is established. The constitutive equation of rubber materials and the mathematical model of the surface of the cylinder are simplified. The essence of rubber friction is due to hysteretic friction. The sliding friction models of the hysteretic friction force in the sinusoidal surface and the random rough fractal surface are derived. Simulation results show that the increase of relative sliding and gas pressure can increase the friction force and the effect of sliding speed is greater. The friction coefficient increases with the sliding velocity. The trend between the friction coefficient and the relative slidng velocity is approximately two parabolic distributions when the relative slidng velocity is betweed 0.1 and 0.5m/s. The resulting change rule has certain engineering value for predicting the friction of cylinder.