Testing Research On Leakage And Seal Clearance Of The Variable Clearance Seal Hydraulic Cylinder

In order to solve internal leakage increasing with pressure of the traditional constant clearance seal cylinder,Professor Zhan and his research team from Wuhan University of Science and Technology proposed the variable clearance seal hydraulic cylinder which is called the third-generation hydraulic cylinder.In this paper,the internal leakage of such new type hydraulic cylinders was studied and the main work was as follows:(1)Considering the character of the variable clearance seal hydraulic cylinder and related test requirements,the test system was designed and the measurement and control software was programmed based on Lab VIEW.The hydraulic circuit of the test system was simulated based on AMESim and the results show that the test system runs smoothly and responds quickly.The results also show that the system is designed reasonably and it can meet the test requirements.(2)The static and dynamic internal leakage test methods were formulated and executed.From the curve fitting,the law between the static and dynamic internal leakage,average amount of the sealing clearance and the pressure was found.Meanwhile,the function between average amount of the sealing clearance and pressure in different stage was derived.Through comparative analysis,it can be discovered that the internal leakage of the variable clearance seal hydraulic cylinder declines obviously.The results show that using lip structure is effective to control the internal leakage.(3)A method based on Eddy Current Sensor for measuring the seal clearance between the lip's outer wall surface and cylinder's inner wall surface was designed.According to the characteristics of the structure,the sensor probe coil and the installation structure of the sensor were designed.Meanwhile,the test plan and result processing plan were also designed.