一种新型的装载机电驱泵控液压转向系统

传统装载机的负荷敏感转向系统存在较高的溢流损失和节流损失，转向过程中能量损耗较大.为提高转向系统的能量利用率，提出一种电驱闭式泵控液压转向系统，采用电控方向盘代替原转向系统中的转向阀和方向盘直接控制同步伺服电机，同步伺服电机转速直接由电控方向盘控制，使液压泵输出转向所需的流量到转向液压缸中.研究中，为验证该系统的可行性，首先建立联合仿真模型；然后构建该转向系统的试验测试样机进行验证，并对比原负荷传感转向系统与改进系统在相同转向工况下的工作特性.由试验结果可知，电驱闭式泵控液压转向系统消除负荷敏感转向系统的溢流损失和节流损失，并降低了转向系统的待机能耗，比负荷传感转向系统节能约56%，提高了转向系统的响应速度，使转向过程更加平稳、迅速. 

A Novel of Pump Controlled Electric-Hydraulic Steering System for Wheel Loaders

The load sensing steering system, which is generally utilized in traditional wheel loaders, uses the fixed displacement pump to supply the hydraulic oil. However, there are a large overflow and throttling loss during the steering process. In order to improve the energy efficiency, a constant pump driven steering system was proposed. The constant pump was designed to be driven by servo motor, independently and directly used to supply the required flow for the proposed steering system. The steering speed of electric controlled steering wheel was adopted to control the speed of servo motor. Firstly, a co-simulation model of pump controlled electric-hydraulic steering system was established to analyze the feasibility of the steering system. Then, a test prototype of steering system was established to validate its dynamic characteristics. Finally, compared with the traditional load sensing steering system, the characteristics of pump controlled electric-hydraulic steering system were concluded. The results show that, based on the pump controlled electric-hydraulic steering system, the throttling losses can be reduced, the overflow losses can be eliminated during the steering process, and the energy consumption can be decreased by 56%. Apart from that, the shock and fluctuation of pressure can also be reclined, improving the system stability.