Numerical research on the characteristics of variable annular gap cushioning for high speed hydraulic cylinder

When the high-speed hydraulic cylinder drives the parts to the stroke terminal, it is often accompanied by strong hydraulic shock. Cushioning is an important aspect in hydraulic cylinder performance, which can greatly reduce the vibration, noise and temperature rise of oil caused by hydraulic shock. In this paper, we presented a variable annular gap cushioning for hydraulic cylinder. Firstly, the working principle of the variable annular gap cushioning in hydraulic cylinder is provided. Secondly, the mathematical model and geometric model of the hydraulic cylinder are established, and the dynamic CFD simulation of the hydraulic cylinder is conducted. Based on the pressure and velocity characteristics of the hydraulic cylinder under different cushioning parameters, the optimal structural parameters of the variable annular gap cushioning can be determined. In addition, the simulation results show that the pressure peak value and pressure fluctuation obviously decrease under the optimal structural parameters of cushioning. The proposed cushion structure and numerical results have scientific and engineering value to promote the innovative development of hydraulic cylinder.