日产EX-200-2型液压挖掘机采用微机控制,具有自动化程度高、复合动作能力强、节能等优点,是一种集成度较高的机电一体化产品。该机采用了高速开关阀控制双联伺服变量柱塞泵,变量系统发生故障时常导致整机工作失常。故障定位和分析比较困难。这里介绍主泵伺服变量系统的原理,以及相关的各种传感器的作用和正常值范围,并提出了变量系统的常见故障模式及排除方法。 Nissan EX-200-2 hydraulic excavator adopts microcomputer control, has the advantages of high degree of automation, strong composite motion capability, energy saving, etc. It is a mechatronics product with high integration. The machine adopts a high-speed on-off valve to control the double-linked servo variable displacement plunger pump. When the variable system fails, it often causes the whole machine to malfunction. Fault location and analysis are more difficult. Here is the principle of the main pump servo variable system, and the role and range of normal values ​​of the various sensors, and the common failure modes and elimination methods of the variable system.