| The hydraulic cylinder is an important executive component widely used in the hydraulic system of industrial equipment such as machine tools and construction machinery.The sealing structure of the hydraulic cylinder is a key component that affects the performance of the hydraulic cylinder.The common sealing structures of hydraulic cylinders mainly include contact seals(seal ring seals),gap seals and piston ring seals.Among them,the gap seal uses the tiny radial gap between the piston and the cylinder to achieve the sealing effect,and has a simple structure and low friction and wear.However,when the sealing gap is constant,there is a contradiction that the load pressure increases and the leakage volume increases,which hinders the promotion and application of gap sealing technology.Therefore,on the basis of summarizing and analyzing the existing hydraulic cylinder variable-clearance sealing technology,this article proposes a hydraulic cylinder variable-clearance sealing structure,which can adaptively adjust the sealing gap according to the pressure change,eliminating or reducing the pressure caused by the increase in pressure.The problem of increased leakage,and can be suitable for double-acting hydraulic cylinders.The main research contents are as follows:(1)A new type of variable gap sealing structure suitable for double-acting hydraulic cylinders is proposed,and the basic structure of the involved piston,piston deformation and sealing gap compensation mechanism are studied.Based on the theory of thin-walled cylinder mechanics,the flow field is established The force model of the sealing structure deduces the calculation formula of the piston radial deformation displacement in the piston deformation area,and obtains the piston radial deformation law that affects the sealing gap,which provides theoretical basis and technical support for design and manufacturing.(2)Analyze the influencing factors of the deformation characteristics of the proposed variable gap seal structure.Using ANSYS numerical simulation methods,in-depth study of the width and thickness of the piston deformation area,the width and depth of the pressure equalizing groove on the piston surface,the pressure value of the low pressure chamber,and the influence of different piston materials and material parameters on the radial deformation displacement of the piston,Determine the sensitive factors to piston deformation and the optimal range of related parameters,and lay the foundation for the optimization of the seal structure.(3)For the proposed variable gap seal structure,the calculation formulas for internal leakage and friction are derived based on the theory of fluid mechanics.Using Fluent software and dynamic mesh simulation technology,the corresponding flow field pressure distribution,internal leakage performance analysis and friction performance analysis are carried out,and the impact of key factors such as the width and thickness of the piston deformation zone and the piston movement speed on the sealing performance are studied.Compare with theoretical calculation results. |
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