挖掘机控制阀操纵性能改善研究及速度调定系统设计

发布时间：2018-05-26 15:26

本文选题：挖掘机 + 先导阀　；参考：《西南交通大学》2017年硕士论文

【摘要】：工程机械行业的不断发展和工作环境的持续变化,对挖掘机的工作性能和效率提出了更高的要求。针对目前挖掘机执行机构的速度调定需要更换多路阀阀芯的问题,.根据先导阀和多路阀的静态数学模型,计算得到执行机构液控回路各控制参数之间的关系,并以此为依据,应用电液比例控制技术将挖掘机液控先导的控制方式更换为电控先导。在电控先导的基础上设计了一套执行机构的速度调定系统,该系统既能根据驾驶员的操纵习惯和工作环境的要求调定单个执行机构的运动速度,还能调定两个执行机构复合运动的速度,无需更换多路阀阀芯,提高了执行机构速度调定的可靠性和灵活性。本文以某中型液压挖掘机为研究对象,主要研究内容如下:(1)通过数学推导的方法,推导出了减压式先导阀触头下降位移与手柄操纵角之间关系的精确计算公式,与现有的线性近似计算公式比较,在手柄操纵角小于20°时,精确计算公式和线性近似计算公式的计算结果基本相等,但操纵角大于20°后,线性近似计算公式的计算误差越来越大。为了提高减压式先导阀的微调操控性能,提出了一种压盘的两段式结构。根据减压式先导阀的静态特性建立其数学模型,得到了输出先导压力与手柄操纵角之间的关系曲线。(2)利用AMESim仿真得到了不同工况下多路阀输出流量与阀芯位移之间的关系,并以此为边界条件,通过Fluent仿真分析多路阀工作时阀芯上稳态液动力的大小,进而分析了稳态液动力的影响因素及其对多路阀工作的影响。计算得到稳态液动力与阀芯位移之间的关系,进而建立多路阀的静态数学模型,得到了先导压力与多路阀阀芯位移之间的关系曲线。(3)基于本文设计的电控先导系统,对挖掘机执行机构速度调定系统的组成及工作原理、硬件选型、步进电机控制和软件设计等方面进行了详细的介绍,调试员能够通过电控手柄上的正负按钮和确定按钮对执行机构的速度进行调定,并保证执行机构按照调定后的速度工作。
[Abstract]:The continuous development of the engineering machinery industry and the continuous change in the working environment put forward higher requirements for the working performance and efficiency of the excavator. In view of the current speed setting of the actuating mechanism of the excavator, the problem of replacing the valve spool is needed. According to the static mathematical model of the pilot valve and the multichannel valve, the liquid control loop of the actuator is calculated. On the basis of controlling the relation between parameters and using the electro-hydraulic proportional control technology, the control mode of the hydraulic control pilot of the excavator is replaced by the electronic control pilot. On the basis of the electronic control pilot, a set of speed setting system of the actuator is designed. The system can not only adjust the single executive according to the driver's control habit and the working environment. The speed of the movement of the mechanism can also adjust the speed of the compound movement of the two actuators, without replacing the multiple valve spool, and improving the reliability and flexibility of the speed adjustment of the actuator. In this paper, a medium hydraulic excavator is used as the research object. The main contents are as follows: (1) the decompression pilot valve is derived by mathematical deduction. The accurate calculation formula of the relation between the drop displacement of the contact and the control angle of the handle is compared with the existing linear approximate formula. When the handle angle of the handle is less than 20 degrees, the calculation results of the exact calculation formula and the linear approximate formula are basically equal, but the calculation error of the linear approximate calculation formula is getting bigger and bigger after the control angle is greater than 20 degrees. In order to improve the micro control performance of the pressure relief pilot valve, a two stage structure of the pressure plate is proposed. According to the static characteristic of the pressure relief pilot valve, the mathematical model is set up, and the relation curve between the output pilot pressure and the handle angle is obtained. (2) the output flow and the valve core displacement of the multiple valve under different working conditions are obtained by AMESim simulation. The relationship between the steady-state liquid power on the valve core and the influence factors of the steady-state liquid power and its influence on the work of multiple valves are analyzed by Fluent simulation, and the relationship between the steady liquid power and the valve core displacement is calculated, and the static mathematical model of the multi-channel valve is established. The relationship curve between the pilot pressure and the displacement of the multi-channel valve spool is obtained. (3) based on the electronic control system designed in this paper, the composition and working principle of the speed adjustment system of the excavator actuator, the selection of hardware, the control of the stepping motor and the software design are introduced in detail. The debugger can pass the positive control of the control handle. The negative button and the confirmation button adjust the speed of the actuator and ensure that the actuator works according to the adjusted speed.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU621

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