Simulation And Analysis Of The Cushioning Process In The Blank End Of Excavator Armcylinder

An compact hydraulic excavator is a widely used engineering vehicle with high degree of integration, multi-function, high efficiency and energy saving, easy operation. The hydraulic cylinder, as its work equipment, compared to other engineering machinery’s hydraulic cylinders, has high speed, high pressure and high impact. The performance of the hydraulic cylinder’s cushioning device directly influences the reliability of the hydraulic cylinder.There are three main research methods for hydraulic cylinder cushioning process: theoretical analysis, experiments and CFD (computational fluid dynamics), which complement each other. Compared to the first two methods, CFD has its own advantages:it can easily get the whole field data; through post-processing, a lot of visual results can be acquired, e.g. velocity vectors, pressure distributions and streamlines, providing a good view of the fluid flow patterns.Experimental and simulation studies on the LG660excavator armcylinder cushioning process have been conducted.From the experimental results, it can be seen that in the blank end of the armcylinder with a tapered cushion piston and a throttle valve,there is a peak pressure at the beginning of the cushioning process and the following changes of pressure is not smooth enough.A numerical work has been performed to analyze the fluid flow in a cylinder. Dynamic mesh model was used to simulate piston motion, k-ε turbulence model was used to predict the incompressible fluid flow in the cylinder. They were solved with finite volume method and commercial CFD code FLUENT. Velocity and pressure distributions are presented to show the fluid flow. It is found that the simulation result has an approximate peak pressure with experiment data but lacks a continus holding pressure.