Numerical Analysis And Experimental Research Of Variable Clearance Seal Hydraulic Cylinder

Variable clearance seal hydraulic cylinder,as the new type of cylinder,possesses numerous advantages such as small leakage,low friction,high volumetric efficiency,rapid frequency response and long working life.It has been testified that the sealability of variable clearance seal hydraulic cylinder improves gradually along with the adding differential pressure in previous studies of NSFC(Natural Science Foundation of China)program — Research on the Technology of Controlled-variable Clearance and Lubricating Mechanism of Sealing Surface Bionic Texture about High Speed Cylinder,and Hubei province key projects of natural science foundation — Basic Research of Clearance Seal Technology about Key Hydraulic Parts in High Speed Heavy Equipment.Therefore,based on these above projects,the deformation theory,the flow of irregular bilateral wedge and annular flow field,and the test of leakage of variable clearance seal hydraulic cylinder are regarded as the research object.The study is summarize as several following parts:(1)According to the force analysis of variable clearance seal piston lip,combined with elastic mechanics,structural mechanics,theoretical mechanics and other multidisciplinary knowledge,it can be confirmed that the loads of transmutative lip are composed of up and down surface distribution load,and axial uniform load.The deformation equation is derived,make it clear that the transformation caused by up and down surface distribution load is several times of which caused by axial uniform load.(2)The piston lip deformation has been analyzed by the method of uniflow fluid-solid coupling optimization simulation.The appropriate structures of piston are got from the simulation,and these structures would be applied in the test.(3)The lip deformation is fitted with two-stage linear function.The variable sealing fluid field is computed with hydromechanics to get the velocity and leakage of different gap.Make it sure that when the length of lip add about 2 millimeter,thequantity of the flow speed between cylinder block and the piston surface will decrease100 millimeters per second.(4)Four types of piston are measured at the performance test platform of hydraulic cylinder.Pressure,leakage and runtime of full lead are collected,used to compare with the calculating data in chapter four.The result of comparison is basically consistent with the theoretical analysis of variable clearance seal hydraulic cylinder.