【作者】 弓永军；

【导师】 杨华勇； 周华；

【作者基本信息】 浙江大学 ， 机械电子控制工程， 2005， 博士

【摘要】 本论文针对三类典型的纯水液压控制阀,从理论分析、样机研制及实验研究等多方面对其工作性能进行了全面而系统的研究。研制出了国内首套高压大流量纯水液压控制阀气蚀特性实验台架,并针对纯水液压控制阀中最典型的节流阀口,研究了不同结构对阀口的流量一压差特性、出口压力及流量系数的影响;同时系统地研究了气蚀特性、密封技术及材料选择等关键技术,并集成地应用这些关键技术,完成了系列高压大流量纯水液压控制阀的结构设计、样机制造及性能优化等方面的研究,取得了一些具有创新性的结果。 研制出了一种基于多级分压、高压引流补偿和分离原则的气蚀抑制新结构和一种能够实现微量调节的轴向三角通槽式节流阀口结构、提出了一种基于敏感腔设置、阻尼器优化以及特殊力放大机构的灵敏控制方法;从流场控制的角度提出了纯水液压控制阀的参数优化设计方法:第一,利用弧形阀芯过渡面,改善节流槽内的压力分布,即:在紧靠阀芯与阀套形成的喷口处的微小区域内形成高于背压的压力峰值,从而抑制气蚀的发生。第二,增大阀套出口直径及锥度,减小出口位置偏差可以有效抑制出口漩涡形成,从而降低了气蚀现象的发生。在以水为工作介质的多级节流阀口、异形结构阀口的气蚀特性试验中,发现刚发生气穴现象时的气穴系数在0.35～0.5之问,与油压系统的气穴系数相近,这一现象在公开文献中未见报道,可为纯水液压控制阀节流阀口的设计提供依据。 本博士论文的主要内容可分为7章,现分述如下: 第一章为纯水液压传动的发展历程及研究现状。能源结构的变化趋势和人类可持续发展的时代要求,是纯水液压技术发展的外在要求;而纯水液压技术本身所具有的介质来源广泛、环境友好、清洁安全的独特优势,则是纯水液压技术崛起的内在动力。本章首先介绍了水液压技术的定义及基本特征;其次归纳了水液压技术的发展历程及其研究内容和难点,并就纯水液压传动在行走机械、食品、医药、娱乐、造纸等场合的应用进行举例说明;最后给出了目前国内外纯水液压控制阀的研究现状、典型代表、关键问题及应用前景;并说明了目前纯水液压控制阀存在的问题及开展纯水液压控制阀关键技术研究的目的、意义及对策。 第二章为纯水液压控制阀气蚀实验系统的搭建。本章首先介绍了纯水液压控制阀气蚀试验系统的设计思想、气蚀实验装置的设计要求,以及气蚀特性实验的测量原理及方法;然后针对测量中可能的误差来源进行分析。 第三章为纯水液压控制阀防气蚀阀口特性研究。水的汽化压力高,可压缩性小,密度大,这使得纯水液压阀中存在严重的气蚀腐蚀和拉丝侵蚀现象,从而导致阀很快失效。要减小或更多还原

【Abstract】 In this thesis, theoretical and experimental studies of the three kinds of water hydraulic valve are comprehensively and systemically dealt with. The test rig of cavitation performance in water hydraulic control valve is first developed interiorly with higher pressure and larger flow. The cavitation phenomenon at the orifice is investigated which is the base of water hydraulic control valve structure design, and the rule is studied which different structures influence the valve characteristic and flux coefficient. At the same time, the key problem are researched as cavitation resistance, seal technology, selected material and so on. The structural design of the water hydraulic control valve, the fabrication and the optimization of the prototype are discussed in detail, and as a result, some important and creative conclusions are achieved as follows:Some new-style structure are designed and the water hydraulic control valve prototype are manufactured. The test results show the over shoot was smaller than 30%, adjusting time was shorter than 500 ms, the control accuracy was 90.7% under 14MPa. Dynamic and static experiments show that the performance of the valves accomplished the expectation. The method are put forward which parameter are optimized from the view of flow field control. The first method is to amend the pressure distribution at the throttle orifice by increasing arc transition surface, the second method is to augment the exit diameter and the taper which can restrain the cavitation extent. The cavitation test results show that the cavitation coefficient is between 0.35 and 0.5 which is close to the value in oil system, also it show that the flux coefficient with two-stage throttle configuration is lower than the flux coefficient with one-stage throttle configuration, but its cavitation resistance is better. The test results show the orifice with sphericity or ellipse structure have preferable rigidity and stronger cavitation resistance.The main contents of this thesis could fall into seven chapters as the followings.Chapter 1 introduces the development and the present status of water hydraulic. Firstly, the definition and the characteristics of water hydraulic is introduced. Furthermore, the historical background of water hydraulic is discussed in tenns of the trends of the trends of the energy resource structure and the needs of the human sustainable development. Its content of the water hydraulic in research and difficulty are sum up. Water hydraulic has been proved successfully in entertainment facilities, food industry, paper machinery, under water tools, fire fighting, and itsapplication are illustrated. In addition, the present status of water hydraulic valve , structure types, typical representations ,the key problems are described as well as intention, meaning and measure of the thesis.Chapter 2 presents a novel apparatus to measure the cavitation . Firstly, the design idea and the design demand are introduced . The experimental apparatus and system to investigate the cavitation are described. The uncertainty in the experimental measurement was analyzed.Chapter 3 studies the performance of the cavitation resistance at the valve orifice. Water has the characteristic as higher vaporization pressure, lower compressibility and higher density. So, there are serious cavitation corrupt in water hydraulic valve, this is a very important causation result in invalidation. In order to reduce or eliminate the status, the appropriate structure design must be considered as well as the suitable material. Firstly, it is introduced which different media performance impact on cavitation erosion. Secondly, the measurement and principle are concluded which can ease or prevent cavitation erosion. Additionally, the experimental study of the valve orifice are carry through with different structure and some conclusion are obtained which can instruct the design of water hydraulic valve.Chapter 4 is about the principle of water hydraulic valve and the development of prototype. Water hydraulic valve is the key component of water hydraulic technology. The difficult problem must be conquered as erode, leakage, cavitation, impulsion, and so on. So, the structure, material, machining technology must be studied in order to manufacture the water hydraulic valve with good property. In water hydraulic valve, many novelty structure and material are adopted. Firstly, three kinds of water hydraulic valve are introduced which are developed by myself. Secondly, some conclusion are sum up about structure , machining art and material.Chapter 5 introduce optimization of the water hydraulic valves. Some parameters are obtained by designer experience in the process of water hydraulic structure design which are elective in a certain extent. The optimize design is mostly measurement to advance the water hydraulic hydraulic valve performance. The chapter develop the optimization design on the basis of aforementioned chapter. Some software are utilized to enhance reliability and efficiency including Matlab/Simulink, Amesim and Fluent. Firstly, the system simulation and flow simulation are carry through on the base of actual structure parameters. Then, the simulation results are analyzed and the parameters are optimized in order to ameliorate performance of thewater hydraulic valve.Chapter 6 studies the performance of the prototype through the experiment. Firstly, the testing rig are introduced including mostly instrument ,meter and its demarcator. Secondly, the experiment item and principle are particularized. Finally, the experiment are accomplished and the experimental results are analyzedChapter 7 is the conclusion and expectation which summarizes and concludes the thesis in many aspects including numerical analysis, system design, fabrication of the prototype, performance testing, etc. Additionally water hydraulic components future development and application are expected.更多还原