基于PWM高速开关阀先导液压桥路的比例阀性能研究

发布时间：2018-06-02 03:13

本文选题：高速开关阀 + 先导液压桥路　；参考：《兰州理工大学》2014年硕士论文

【摘要】：高速开关阀具有结构简单、抗污染能力强和价格低的优点,通常以多个高速开关阀构成液压桥路的形式,作为两级比例阀的先导级使用。然而,高速开关阀先导液压桥路存在死区过大和通流能力不足等问题,导致其用于高精度、大流量比例阀中时,存在主阀流量控制精度不高、响应速度较慢,甚至引起主阀芯振动,严重制约了其在比例阀中的使用范围。本文以高速开关阀先导液压桥路比例阀为研究对象,研究了其先导液压桥路的死区特性和空载流量特性,以及这些性能对主阀流量控制精度和响应速度的影响。分析了影响高速开关阀先导液压桥路比例阀控制精度和响应速度的因素,提出了用先导液压桥路差动流量法提高主阀控制精度,和双阀并联法提高主阀响应速度的方法。在综合考虑提高主阀流量控制精度和响应速度的结构和方法后,提出了六高速开关阀液压桥路为先导级,主阀采用矩形窗口和阀芯位移电反馈的比例阀结构思想。与四高速开关阀先导液压桥路比例阀相比,六高速开关阀先导液压桥路比例阀具有更高的控制精度,更快的响应速度,并有效减小了其主阀阀芯的振动。各章主要研究内容如下：第一章,综述了脉宽调制技术和高速开关阀技术在国内外的发展现状,介绍了以高速开关阀液压桥路为先导级的比例阀在工业领域中的应用,分析了其存在的不足之处,并提出了本文的研究内容和技术难点。第二章,论述了PWM(脉宽调制)高速开关阀先导液压桥路比例阀的结构和工作原理,分析了其优缺点。第三章,研究了高速开关阀先导液压桥路的死区特性、空载流量特性,并分析了由死区特性引起的高速开关阀先导桥路控制精度低的问题。第四章,论述了影响高速开关阀先导液压桥路比例阀控制精度的因素,提出了先导液压桥路采用差动流量结构,主阀采用矩形阀口和阀芯位移电反馈结构,提高主阀控制精度的方法,着重分析了先导液压桥路在差动流量模式下的控制性能。第五章,论述了高速开关阀先导液压桥路比例阀响应速度的影响因素,提出了先导液压桥路采用双阀并联结构,主阀采用能使控制腔体积变小的推杆结构,提高主阀响应速度的方法,着重分析了先导液压桥路在双阀并联模式下的控制性能。第六章,提出了将原来的四个高速开关阀改进为六个高速开关阀,构成先导液压桥路,主阀采用矩形窗口和阀芯位移电反馈的结构思想。论述了六高速开关阀先导液压桥路比例阀的工作原理和结构,仿真分析了六高速开关阀先导桥路的空载流量特性和对主阀芯运动的控制性能。最后,总结全文的主要研究成果,阐述了本论文的研究结论和创新点,对进一步的研究工作进行了展望。
[Abstract]:High-speed switch valve has the advantages of simple structure, strong anti-pollution ability and low price. It is usually used as the pilot stage of the two-stage proportional valve in the form of hydraulic bridge formed by multiple high-speed switching valves. However, there are some problems such as too large dead zone and insufficient flow capacity in the pilot hydraulic bridge of high speed switch valve, which leads to its high accuracy and low flow control accuracy and slow response speed when it is used in large flow proportional valve. Even causes the main valve core vibration, seriously restricted its use scope in the proportional valve. In this paper, the dead zone and no-load flow characteristics of the pilot hydraulic bridge are studied, and the effects of these characteristics on the flow control accuracy and response speed of the main valve are studied. The factors influencing the control accuracy and response speed of the proportional valve of the pilot hydraulic bridge of the high speed switch valve are analyzed. The method of improving the control accuracy of the main valve by differential flow method of the pilot hydraulic bridge and the method of increasing the response speed of the main valve by the parallel connection method of the two valves are put forward. After considering the structure and method of improving the flow control precision and response speed of the main valve, the paper puts forward the proportional valve structure thought of the hydraulic bridge of the six high speed switch valve as the leading stage, the main valve adopts the rectangular window and the electric feedback of the displacement of the valve core. Compared with the pilot hydraulic bridge proportional valve of four high speed switch valves, the pilot hydraulic bridge proportional valve of six high speed switch valves has higher control accuracy and faster response speed, and effectively reduces the vibration of its main valve core. The main contents of each chapter are as follows: In the first chapter, the development status of pulse width modulation technology and high speed switch valve technology at home and abroad is summarized. The application of proportional valve with hydraulic bridge circuit of high speed switch valve in industrial field is introduced, and its shortcomings are analyzed. The research contents and technical difficulties of this paper are also put forward. In the second chapter, the structure and working principle of PWM (Pulse width Modulation) high speed switch valve pilot hydraulic bridge proportional valve are discussed, and its advantages and disadvantages are analyzed. In chapter 3, the dead-zone characteristic and no-load flow characteristic of the hydraulic pilot bridge of high speed switch valve are studied, and the problem of low control precision of the pilot bridge of high speed switch valve caused by dead time characteristic is analyzed. In chapter 4, the factors that affect the control accuracy of the proportional valve of the pilot hydraulic bridge of the high speed switch valve are discussed. The differential flow structure of the pilot hydraulic bridge is put forward, and the electric feedback structure of the rectangular valve opening and the valve core displacement is used in the main valve. The control performance of pilot hydraulic bridge in differential flow mode is analyzed. In the fifth chapter, the factors influencing the response speed of the proportional valve in the pilot hydraulic bridge of the high speed switch valve are discussed, and the parallel structure of the pilot hydraulic bridge with two valves is proposed. The main valve adopts the push rod structure which can make the volume of the control chamber smaller. In order to improve the response speed of the main valve, the control performance of the pilot hydraulic bridge in the dual valve parallel mode is analyzed. In the sixth chapter, it is proposed that the original four high speed switch valves should be improved into six high speed switch valves to form a pilot hydraulic bridge. The main valve adopts rectangular window and electrical feedback of valve core displacement. This paper discusses the working principle and structure of the pilot hydraulic bridge proportional valve of the six high speed switch valve, and simulates and analyzes the no-load flow characteristics of the pilot bridge of the six high speed switch valve and its control performance to the movement of the main valve core. Finally, the main research results of this paper are summarized, the research conclusions and innovations of this paper are expounded, and the further research work is prospected.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH137.5

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