【作者】 麻井伟；

【导师】 姚平喜；

【作者基本信息】 太原理工大学 ， 机械工程， 2007， 硕士

【摘要】 液压平衡阀是平衡回路中的关键元件，在现代工程机械特别是起重运输机械中应用广泛。其性能的好坏直接影响整机的性能，如果设计的不合理，将使设备的作业受到限制，同时给整机的稳定性、动臂及机架的刚性带来不良影响。传统的平衡阀存在着许多缺点，如低频抖动，控制压力偏高，工作平稳性差以及系统功率损失严重等，特别是其调定背压是固定不变的，当负载产生的压力比平衡阀调定的压力高(大负载)的时候，系统的低频抖动不能完全消除，当负载产生的压力比平衡阀调定的压力低(小负载)时，存在控制压力过高，功率损耗大的问题。针对这些缺陷，本文提出了一种新型的负载敏感平衡阀。本文中负载敏感平衡阀是在总结传统平衡阀设计经验，分析平衡阀最新发展成果的基础上设计出的一种新型的平衡阀。该平衡阀应用了负载敏感原理，将油缸下腔压力信号反馈到阀内，使阀芯的开口大小随负载变化，从而根本上解决目前平衡阀存在背压不能随负载动态变化的问题。本文对负载敏感平衡阀的原理进行了深入阐述，对其结构进行了全面设计，特别是对该阀的关键零部件进行了详细的计算。通过对阀口的设计计算，对平衡弹簧的设计计算，提出采用双弹簧以适应非线性阀口的不同区段的负载，从而极大地改善了该阀的调节性能及控制性能。设计中将给出不同弹簧作用下阀芯位移与节流阀芯开口量的函数关系图线以及节流口实际面积与理论面积的对比图。采用Matlab／Simulink软件对该平衡阀进行了动静态仿真分析。仿真结果表明，输入为阶跃负载信号和阶跃流量信号时，系统均在1s左右达到稳态，与其它平衡阀产品(如文献轻载1.5s，重载2.1s)相比有明显提高。本文最后结合该阀的特点设计出了一套完整的试验方案。本文的创新点在于提出了一种全新原理的平衡阀(该阀已申请发明专利，申请号：200610102007.X)，并对该阀进行了比较全面的分析。更多还原

【Abstract】 Hydraulic counterbalance valve is a key element in the hydraulic balanced loop , which is applied abroad in modern engineering mechanism especially in elevating machinery. The performance of the complete appliance is influenced by the property of the counterbalance valve, so, if the design is irrational, the working of the equipment is confined, at the same time, the stability of the complete appliance and the rigidity of the movable beam and the frame are effected badly. There are many pieces of disadvantage in conventional counterbalance valves, such as whipping in Low Frequency, the high control pressure, the bad working stability, the large power loss, and especially the changeless backpressure set up. When pressure brought by load is higher (large load) than pressure set up by counterbalance valve, systemic Low Frequency whipping can’t be eliminated clearly, but when lower (small load), the control pressure is very high and the power loss is very large. Aiming at the disadvantage above, a new sort of load- sensing counterbalance valve is researched in this paper.The load-sensing counterbalance valve in this paper is a new kind of counterbalance valve which is designed on the basis of summary of the designing experience of conventional counterbalance valves and the analysis of the latest outcome. The load-sensing theory is applied in this designing, which the pressure signal from the lower cavity of hydraulic cylinder is fed back to the valve to make the size of valve plug uncork change according to the load change in order to solve the exiting problem that the backpressure can’t change with the load pressure thoroughly.In this paper, the theory of load sensing counterbalance valve is elaborated, its structure is detailed and especially, its key parts are computed in detail. According to design calculation of the valve port and compensating spring, dual spring and non-linear valve port are adopted to adapt to various section load, so as to the regulation performance and control performance of the valve are ameliorated hugely. The functional relationship graphic between spool traverse and axial relief with various springs function and the comparison diagram between real area of orifice and theoretical are given in this design.Static state and dynamic emulation about the new counterbalance valve are carried out by the software Matlab/Simulink. The outcome of emulation proves that with the step load signal or step flow signal, system can reach steady state all the time in about ls,which is obviously improved compared with other counterbalance valve products (such as literature: at fractional load 1.5s and burden 2.1s).A whole suite of testing program is thought out at last in this paper in view of the characteristic of this valve. The innovation points of this paper are that a kind of counterbalance valve (it has been declared patent of invention and the application number of patent is 200610102007.X) with completely new theory is brought forward and complete analyses are carried out it.更多还原