Performance Simulation And Test Of Water-based Lubricated Contact Sealing Elements

In order to achieve higher pressure and higher flow rate of the hydraulic system,the equipment must have a sealed working chamber that does not leak.For some oil-lubricated motion friction pairs,gap sealing methods,such as oil pressure sliding valves,are often used.However,for low-viscosity water-based media,its viscosity is low and it is easy to leak.The gap sealing method can not meet the sealing requirements.Contact sealing is an inevitable choice to realize high pressure and large flow of water-based system.Therefore,the choice of contact seals is critical to the proper functioning of water-based hydraulic components and systems.Rubber material is widely used in sealing field because of its characteristics of high elasticity and large deformation to compensate leakage gap,but the lubrication property of rubber material is not good when the starting resistance is large and the speed of movement is fast.At present,the development trend of sealing technology at home and abroad is to combine self-lubricating materials such as poly tetra fluoroethylene(PTFE)into slip rings with rubber seals,which can replace the shape of sliding rings according to the use environment and equipment.For example,the market more mature circle of Grail and Stefan and so on.However,there is little research on the diversity ofthe composite seals shortly after the appearance of the seals.In this paper,a T-type composite seal is selected for analysis,which provides the original data for the design of relevant hydraulic components and the development of seal types.In this paper,the properties and characteristics of rubber materials and PTFE are introduced and analyzed,the causes of oil film formation and the formula for calculating the thickness of oil film are studied,and the formulas of friction force and leakage amount are calculated according to the fluid dynamics.The method of reducing leakage is analyzed theoretically.The finite element model of T-type composite seal is established by using ANSYS software,and the effects of different media pressure,seal clearance,friction coefficient and seal structure on seal performance are simulated.The curve of contact stress distribution on the contact surface is obtained.The contact force and friction force of the contact surface under various working conditions are obtained by curve fitting and formula calculation.A reciprocating sealing performance test bench was developed.Based on the experimental principle and measurement accuracy requirements,a measurement plan was developed,and key experimental instruments and components were selected.The value of the friction force under different medium pressures when the moving speed of the plunger rod is constant is calculated through experiments.The experimental data shows that the friction force increases with the increaseof the medium pressure when the friction speed is constant,which is consistent with the trend of the simulation calculation.Provides raw friction reference data and calculation methods for the design of water-based hydraulic components and hydraulic systems.