Research On Cushion Plunger Structure Of High-speed Pneumatic Cylinder

Pneumatic cylinders are common pneumatic actuators,and their high-speed development occupies an important position to improve industry efficiency.However,the cylinder will occur to impact and rebound at the end of stroke when the working conditions change,even if the cylinder is in a good cushion state.So the cushion problems have constrained the development of high-speed cylinder.The objective of this thesis is to design a kind of cushion plunger structure which has a stronger ability to adapt to the changes of working conditions.The simulation software was developed using the MFC framework and MSChart graphics controls in language Visual C ++.The mathematical models of energy,flow and movement for the cushion motion were established,which were based on the gas dynamics.These models were solved by Runge-Kutta method.The dynamic characteristics curves of pressure,velocity and displacement were obtained.Cushion test was conducted under the same conditions as the simulation,which was proved that the simulation program and mathematical model are proper.The test bench of high-speed cylinder was set up to research on the cushion performance.Signals acquisition was with the help of sensors and the data collection program was based on Matlab/Simulink.Analyzed the effect on cushion properties when the supply pressure,mass load and maximum speed changed.From the view of energy conservation,the unbalanced relationship and the trend of absorbed energy and impact energy was studied.Then the destroyed mechanism of cushion properties was revealed.Analyzed the change rule of the exhaust throttle area with the displacement by modeling and simulation,and this rule was applied to the structural design of the cushion plunger.Improved the traditional cushion,a new cushion idea was proposed.Three kinds of plunger structures including staged type,parabolic type and equally spaced type were designed and made.The experimental results show that the staged type structure can adapt to the changes in supply pressure and the maximum rate of ±20%,and the change range of mass load is ±60%.The parabolic type structure can adapt to supply pressure change from-40%to +17%,and the maximum speed change from-50%to +25%.The equally spaced type structure can adapt to the change range of supply pressure is ±10,and the maximum speed change from-23%to +12%.