液压缸是液压系统重要元件，其动静态特性直接影响液压系统正常工作性能。由于具有密封件的第一代液压缸摩擦力大、动态性能差，不适应高频工作的液压伺服系统，制约了液压缸向高速方向发展，第二代间隙密封液压缸采用恒间隙密封技术，摩擦力减小，动态响应提高，但容积效率降低。为此，在第一代和第二代基础上，经过多年努力，研发出无密封件并采用压力自补偿变间隙密封技术的第三代液压缸，通过理论分析、数学建模、仿真研究、试验验证及应用，第三代液压缸动静态性能好，容积效率高，工作寿命长，适用于高频响、高速度的液压传动及液压伺服系统。压力自补偿变间隙密封技术可以推广到其他具有微小变形要求的液压元件中，使制造业和液压技术在创新上前进一步。
Hydraulic cylinder is an important component of the hydraulic system. It directly affects the static and dynamic characteristics of the hydraulic system. The first generation of hydraulic cylinder with rubber seals has great friction and poor dynamic performance. Hence, it is not adapted to the hydraulic system with high frequency and restricts the development of high-speed hydraulic cylinder. The second generation of hydraulic cylinder with clearance gap seals uses constant gap sealing technology to decrease the friction and improve the dynamic response, but the volume efficiency is reduced. After years of researches,the third generation of hydraulic cylinder without seals using pressure self-compensation and variable clearance technology is developed on the basis of the first and second generation of hydraulic cylinders. After theoretical analysis, mathematical modeling, simulation research, experimental verification and applications, it is proved that the third generation of hydraulic cylinder had perfect static and dynamic characteristics and long working life. It is well applied to high frequency response and high-speed hydraulic transmission and hydraulic servo system. These technologies can be extended to other hydraulic components that require small deformation, and can make the manufacturing and the hydraulic technology go forward.
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