盾构机推进液压系统的改进

The Optimization of the Shield Machine Propulsion Hydraulic System

盾构机推进液压系统由于比例变量泵调速+比例减压阀调压节能比高而在工程中得到了广泛应用,但此系统中的比例变量泵在高低压推进与拼装模式转换过程中,泵中比例阀存在较大的换向振动冲击,导致推进与拼装模式转换时发生泵站元件、密封装置和管路损坏等风险。在比例变量泵供油口和比例换向阀之间增加减压阀,使泵中比例换向阀按需平稳换向;在速度控制上,比例变量泵最低供油量不能满足微速推进复杂工况的要求,因此采用变量泵与微速阀联合控制的方法;在油缸锁紧保压控制上,液控单向阀控制口从主换向阀中位机能“B”口与油缸有杆腔之间的油路引入,一旦主换向阀发生故障,将导致液控单向阀控制口油路不能导通并无法关闭,正在拼装管片的油缸也将受到液压油泄漏导致油压降低顶管片油缸活塞杆松动带来的安全隐患。液控单向阀控制口从高压过滤器出油口与主换向阀中位机能“P”口之间的油路由一个独立小换向阀引入,使液控单向阀控制口油路操作变得简单安全,避免了紧急情况下油缸活塞杆松动造成管片脱落的风险。分析改进前后液压系统的工作原理,通过和实际应用对比,验证了改进后系统的节能、安全和稳定等优点,为盾构机推进液压系统的开发提供参考。

Proportional variable pump controlled speed regulation+proportional pressure relief valve pressure regulation of the shield machine propulsion hydraulic system is widely used in engineering due to the high energy-saving ratio,but during the conversion process between high and low pressure propulsion and assembly modes of the proportional variable pump in this system,there is a significant reversing vibration impact on the proportional valve in the pump,which will lead the damaged risks of pump station components,sealing devices and pipelines when the propulsion and assembly modes are switched.The pressure relief valve were added between the proportional variable pump supply port and the proportional reversing valve to make the proportional directional valve in the pump reversing smoothly as needed.In terms of speed controlling,the minimum oil supply of proportional variable pump cannot meet the requirements of complex conditions of micro-speed propulsion,so the joint control of variable pump and micro-speed valve was adopted to meet the stable micro-speed propulsion of the shield machine.In terms of hydro-cylinder locking controlling,the liquid control check valve control port was introduced from the oil circuit between the middle function"B"port of main reversing valve and the piston rod chamber of the hydro-cylinder.Once the main reversing valve is faulty,it will cause the control port oil loop for the liquid control check valve unclosed,and the hydro-cylinder assembling the tube segment will also be subject to the safety hazard caused by the loosening of the piston rod of the head segment cylinder.The control port of the liquid control valve and the oil circuit between the oil outlet of the high-pressure filter and the middle function"P"port of the main return valve was introduced by a separate small return valve,the operation of the control circuit was simple and safe,the tube segment shedding risk of the piston rod caused by the loose hydro-cylinder under an emergency condition was avoided.Through analyzing the working principle for the hydraulic system before and after the improvement,and comparing with practical application,it verifies that the system has the advantages of energy saving,safety and perfection,which can provide reference for the research of the propulsion hydraulic system for the shield machine.