| Pneumatic technology is more and more widely used in the automotive,medical equipment,robotics and other industries due to its high speed,safety and cleanliness.With the implementation of the China Manufacturing 2025 strategy,cylinders are used more widely in smart factories,and the high precision of the cylinders requires higher requirements for the dynamic friction characteristics of the cylinders.Therefore,in-depth study of the friction characteristics of the seal ring and its mechanism can lay a foundation for improving the performance and service life of the cylinder.In this paper,the typical cylinder sealing ring is taken as the research object.The theoretical analysis,numerical simulation and experimental research are combined to carry out the experimental research on the dynamic friction characteristics of the cylinder.Firstly,based on the research of dynamic and static friction model,a Lu Gre friction prediction model is established by considering the effect of contact area.The steady-state model is developed by considering the contact area based on the dynamic friction model of the cylinder,and the static parameters of the friction model of the seal are characterized.In addition,for the aging behavior of the cylinder seal material,the influence law of the aging on the parameters of the cylinder friction model is revealed,which lays a theoretical foundation for the study of the friction behavior of the cylinder service process.Secondly,a dynamic friction simulation model of rubber sealing material was established by using the finite element method.Based on the stress-strain experimental data of sealing rubber material,the constitutive model of nitrile rubber material was developed.Then,the finite element model of friction process was developed by ABAQUS software.The influence law of aging on the dynamic contact area in rubber friction process were studied by experiment and simulation method.Thirdly,considered the influence of the surface quality and dimensional accuracy of the cylinder,a multi-scale simulation model of cylinder friction is developed.The three-dimensional topography of the cylinder surface was obtained by DXS160 digital microscope.Then,the rough surface characterization model was established.Based on this,the macro-micro simulation model of the cylinder dynamic in friction process was established under complex conditions,the influence of surface roughness and dimensional accuracy on the friction behavior were studied.The results provides a theoretical basis for the design of high performance cylinder seal and friction performance.Finally,an experimental study on the dynamic friction characteristics of the seal was carried out under complex conditions.Based the hot-humid aging tests of the sealing ring and sealing material,the influence of aging on the compression set rate,stress-strain and elongation at break of the sealing material was revealed.The FTIR infrared spectroscopy was used to analyze the hot-humid aging mechanism of the rubber sealing material.Then,the intrinsic relationship between molecular structure and macroscopic mechanical properties was reveal.Based on the self-made friction experimental platform,the experimental study on the contact characteristics and friction characteristics of sealing materials under aging and other factors was carried out,and the simulation results was verified. |
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