Design and Rig Test of Hydro-Pneumatic Spring for Heavy Off-Road Vehicles

Abstract In order to meet the requirements of heavy off-road vehicles for long-stroke elastic elements, a new type of double-chamber hydro-pneumatic spring was innovatively designed. According to the structure and working characteristics, the mathematical models of the spring under two working conditions are established, and its stiffness characteristics are analyzed. The force and displacement data of the spring at different frequencies were obtained by rig test. The static friction, damping and elastic force of the spring are separated. Based on the data of elastic force and displacement, the polytropic exponent of hydro-pneumatic spring under different working conditions is identified by curve fitting. The structure and theoretical model of double-chamber hydro-pneumatic spring designed in this paper provide support for the application of hydro-pneumatic spring in long-stroke off-road vehicle.