Design Analysis And Optimization Of Leak-free Plunger Cylinder For Large Stroke Condition

After a long time of development,the sealing technology of hydraulic cylinder has been greatly improved in restraining leakage.However,the leakage problem has not been completely solved in practical engineering.To solve the problem of hydraulic cylinder leakage,the author’s team proposed a leak free plunger cylinder,which uses the seal of "top hat" structure to replace the traditional seal ring.In principle,there is no leakage.However,the structure of the leak free plunger cylinder will cause the elastic deformation of the seal when the plunger extends,which is subject to the deformation limit of the seal and is not easy to achieve a large stroke.In this paper,the non leakage piston cylinder with large stroke is designed,the finite element analysis and experimental verification are carried out,and the key component seals are optimized.In this paper,the leakage free piston cylinder is designed and analyzed to achieve a larger stroke in the working process of the piston cylinder.Based on the original straight tube structure,the laminated structure is designed,and the action principle of the laminated structure is analyzed.Based on the finite element method,the finite element simulation of the piston cylinder fast forward working condition of the straight cylinder seal and the laminated seal is carried out to verify the rationality of the design.Using ABAQUS software and Mooney Rivlin model,the deformation process of the seals with two structures is analyzed and calculated,and the strain,Mises stress and shear stress under different stroke are analyzed.The comparative analysis shows that the laminated seals can realize the working condition of large stroke of the plunger cylinder.The design experiment verifies the accuracy of the finite element simulation.In order to clearly get the deformation state of the seal under a large stroke,a double-layer plunger cylinder prototype is designed.The inner cylinder is a transparent cylinder,and the outer cylinder is a perforated steel cylinder.During the experiment,pictures were taken to obtain the deformation state of the seal at different positions during a large stroke.The experimental results and simulation results are compared and analyzed to verify the rationality of the laminated structure and the accuracy of the simulation results.The multi-objective optimization is carried out for the seal of the laminated structure,with the stacking angle and stacking distance as the optimization variables,and the minimum stress value at the inner stacking corner and the minimum stress value at the outer stacking corner as the optimization objectives.The optimal Latin hypercube design method was used to design the experiment.A total of 16 groups of experiments were designed,and the test results were obtained by finite element simulation;Based on the test results,the second-order response surface optimization model is established;Multi Island genetic algorithm is used to optimize the model,and the optimization results are obtained.According to the optimization results,the optimal size of laminated seals is determined.The finite element simulation of the optimized piston cylinder under fast forward and working conditions verifies the rationality of the optimized design.