液气复合驱动液压挖掘机动臂运行特性及能效

液压挖掘机作业中，大质量动臂举升储存的势能经液压阀口节流转化为热能耗散，不仅浪费能源，还使液压油温度升高，需附加冷却系统降温，增加了机器的成本和复杂性。为解决上述问题，在原有负载敏感驱动回路的基础上，提出基于三腔液压缸的工作装置自重液气平衡势能回收利用方法，三腔液压缸中一个油腔与液压蓄能器直接连通，存储利用工作装置的势能。研究中，首先根据前期的仿真结果，建立了基于三腔液压缸的液压挖掘机测试样机，通过试验，分析对比了分别采用两腔液压缸和三腔液压缸驱动动臂的运行特性与能效特性，测试结果表明，增加液气储能容腔后，提高了系统运行的平稳性，动臂运行过程中的能耗降低48.5%，峰值功率降低64.7%，节能效果显著。新的方法也同样适用于各类液压缸驱动的重载举升装置。

Operating Characteristics and Energy Efficiency of Hydraulic-gas Combined Driving Hydraulic Excavator Boom

In the hydraulic excavator operation process, potential energy of large mass stored in lifting phase is converted into heat energy and dissipated, which not only wastes energy, but also increases the temperature of the hydraulic oil. Additional cooling equipment is required to reduce the temperature so the cost and complexity of the machine is increased. In order to solve the above problems, the potential energy recovery method of hydraulic-gas self-weight balancing using three-chamber hydraulic cylinder is proposed on the basis of the load sensing driving circuit. A chamber of the three-chamber cylinder is directly connected with a hydraulic accumulator in order to store and reuse the potential energy of the boom. Based on the simulation results, a prototype of hydraulic excavator based on three-chamber hydraulic cylinder is established. The operating characteristics and energy efficiency characteristics of the boom driven by two-chamber hydraulic cylinder and the three-chamber hydraulic cylinder are studied experimentally. The test results show that the stability of the system is improved after adding a hydraulic-gas storage chamber and 48.57% of the energy consumption could be reduced as well as 64.76% of the peak power could be reduced. The energy saving effect is remarkable. The new method can also be used in various types of heavy lifting devices driven by hydraulic cylinders.