The Research On Sealing And Friction Performance Of Cylinder Sealed By A PTFE Composite

The cylinder is the main actuator in the pneumatic system.Owing to the friction,its use in high-precision control,low-speed operation,stable driving and other occasions is greatly limited.PTFE composites have low friction,low wear and other excellent characteristics,and perform well in the sealing field.Therefore,applying it to the cylinder seal to reduce the friction and improve the sealing performance,which is great significance for the practical application of the cylinder.This dissertation researches the sealing and friction performances of PTFE composites under the cylinder sealing conditions at first,then designs the sealing ring.Finally,the reducing friction and sealing effect of PTFE composites in cylinder seal are verified by the experiments.The main contents are as follows:(1)The mathematical model of cylinder leakage is established,and analyzes the influencing factors of leakage.The model of coaxial seal is created by combining the characteristics of PTFE composites.The sealing performance of PTFE composites is analyzed after simulating the piston sealing conditions by finite element software,which obtains the reference value of designing sealing ring and setting experimental conditions for friction performance of PTFE composites.(2)A PTFE composite is selected,and its friction mechanism with aluminum alloy material of cylinder is analyzed according to the theory of friction.Experimental conditions are set on the basis of the friction conditions at piston seal and the sealing performance of the PTFE composites,the friction performance of PTFE composites is tested by the friction tester,which concludes the friction performance of PTFE composites under the piston seal and obtains the reference value of designing sealing ring.(3)The sealing ring is designed on the basis of the research results of the sealing and friction performances of the PTFE composites,and the processed sealing ring is inserted into the tested cylinder.(4)The test-bed for cylinder sealing performance and friction performance is built to test the cylinder sealed by PTFE composites.And the experimental result verifies the effect of PTFE composites on reducing friction by comparing with rubber sealed cylinder.