【作者】 宋海涛；

【导师】 吴晓光；

【作者基本信息】 中国地质大学 ， 机械设计及理论， 2008， 硕士

【摘要】 全液压钻机由于具有结构紧凑、传动平稳、操纵简单以及容易实现无级变速等优点,在工程施工、地质勘探、瓦斯抽采等领域得到了广泛应用。国内钻机目前大多采用传统的定量泵+溢流阀的阀控液压系统,系统油液温度容易升高,能量损失较为严重,因而有逐渐被具有节能性的新型液压控制系统取代的趋势。目前全液压钻机中采用的节能控制系统一般为负载敏感液压系统。因此,非常有必要对负载敏感液压系统的动态特性展开研究。论文以负载敏感液压系统的动态特性为着眼点,结合ZDY6000L型履带式瓦斯抽采钻机的液压系统,从理论建模和数字仿真两个方面展开研究,主要工作如下:1.对履带钻机的液压系统进行理论分析和数学建模。履带钻机的液压系统主要有5个重要回路,结合钻机的不同工况,分析了各个回路的执行机构、工况特点和负载特性。在分析负载敏感液压系统工作原理的基础上,运用功率键合图的建模方法,对负载敏感液压系统的回转系统进行了建模,分别绘出了系统在恒流和恒压两个工作状态的功率键合图模型。并整理出了负载敏感液压系统的数学模型。2.对系统中关键液压元件负载敏感阀和限压阀进行建模,并建立负载敏感回转液压回路的简化模型。在对两个液压元件工作原理分析的基础上,使用仿真软件AMESim分别对这两个液压元件进行建模,并经过仿真表明所建立的液压元件的AMESim模型模拟工作特性与实际的液压元件工作特性相一致。利用AMESim软件建立了钻机负载敏感回转回路液压系统的模型(负载敏感阀的压差设定为2MPa),并对负载敏感液压系统的工作特性进行了仿真。仿真结果显示,钻机在待机状态时系统输出为低压小流量,正常工况时系统输出恒定流量且系统压力随负载压力的变化而变化并始终比负载压力高出某一固定值,超载工况时系统输出为高压小流量。仿真结果验证了钻机回转回路在应用负载敏感液压系统后稳定、节能的特点。3.系统研究了负载反馈油管对液压系统动态特性的影响。结合所建的回转系统AEMSim模型进行仿真,当油管直径为6mm时,负载反馈油管长度在0.5m到10m范围内负载反馈油管越长,系统响应速度越慢,但是稳定性越好;当油管长度超过10m时,系统失去负载敏感特性,响应速度变慢,稳定性变差。4.对ZDY6000L型履带钻机进行了实验研究。重点测试了钻机回转回路的工作特性以及应用负载敏感液压控制系统后的能量利用率,实验结果表明钻机在应用了负载敏感液压系统后回转系统稳定性好、回转效率较高。且系统在高压力工作区的效率要高于低压力工作区,特别是在大扭矩低速钻进工况效率较高,达到50%以上。本文以履带钻机负载敏感液压系统为研究对象,对其动态特性进行了仿真研究,该研究为负载敏感液压系统的设计提供了一定的依据,为进一步利用数字仿真法对负载敏感液压系统的动态特性研究奠定了基础。更多还原

【Abstract】 Hydraulic drill is widely used in the area of construction, earth exploration and gas drainage due to the advantage of compact structures, stable motion, easy operation and feasibility to change the velocity. However, the domestic hydraulic systems mainly use the traditional pump-valve control system, resulting in the oil temperature rising and severe energy loss. Therefore, the traditional way of valve adjustment is going to be replaced by an ideal energy saving hydraulic system. The most popular energy saving control system nowadays is load sensing hydraulic system. Therefore, it is necessary to study such system and analyze the factors that may affect the dynamic performance of the system, providing some foundation to the future design.Taking the ZDY6000L crawler drill as an example, focusing on the dynamic performance of the load sensing hydraulic system, this paper mainly deals with the theoretical modeling and digital simulation. The main work is summarized below.Firstly the paper deals with theoretical analysis and mathematical modeling of the crawler drill’s hydraulic system. The hydraulic system is mainly composed of five full circuits. Combined with drills’ different condition, the paper analyzes the operation structure, work condition and load characteristics. Based upon the load sensing work principle analysis, with the power bond method, the model of the rotation part of the hydraulic system is built and the system’s power bond model under constant current and constant voltage is depicted. Mathematical model of the load sensing hydraulic system is obtained.Secondly the paper builds the model for key hydraulic component of load sensing and pressure control valve and set up the simple model of load sensing rotation circuit. After we understand the working principle of the hydraulic components, commercial software package AMESim is used to build the model of these two components. Simulation results agree well with the real situation. The paper employs the AMESim to build the drill’s load sensing hydraulic rotation circuits model and do the simulation to obtain the system’s working performance (the pressure difference of load sensing valve is 2MPa). The simulation results shows that: 1) the output of the system of waiting-for-work condition is low pressure and small amount of flow rate; 2) the output of the normal working condition is constant amount of flow rate and pressure changing with the load pressure, always higher than the load pressure by certain amount; 3) the output of the overload condition is also high pressure and small amount of flow rate. The simulation confirms the stability and energy saving characteristics of the drill’s rotation circuits after the application of the load sensing hydraulic system.Thirdly the paper involves with the effect of load feedback pipe on dynamic performance of hydraulic system. Simulation is made on the model of rotation system in AMESim environment. The results indicate that while the pipe length is in the range of 0.5m to 10m, the longer the feedback pipe, the slower the response, the better the stability of the system; while the pipe length is longer than 10m, the system lost load sensing attributes, the response trend to slow and the stability is getting worse.Fourthly the paper shows the experiments study on ZDY6000L crawler drill. We mainly test the drill’s rotation circuits’ performance and energy utilization rate when we apply the load sensing hydraulic control system. The experiments show that the drill’s performance, including stability and high rotation efficiency, is much better. Furthermore, the system’s working efficiency is higher at high pressure work place than that of low pressure, especially at the high torque and low velocity working condition, even up to 50%.In conclusion, this paper mainly focuses on the crawler drill’s load sensing hydraulic system, simulates the dynamic performance, and provides the fundamental information of designing the load sensing system and numerical simulation of dynamic performance of the load sensing hydraulic system.更多还原