全水液压驱动压铸机压射控制关键技术研究

The die casting is an advanced precision molding technology with high efficiency and is widely used in the manufacture of mechatronics equipments. At present, the die casting machine is mostly driven by oil hydraulics, and has the disadvantage of pollution, leakage, flammability and explosion. Compared with the die casting machine powered by oil hydraulics, the die casting machine powered completely by water hydraulics has the prominent advantage of environmental protection and safety under high temperature. The injection system is a key part that determines the performance of the die casting machine, and has a direct effect on the surface quality of castings, contour size and compactness. This project focused on the injection system of the die casting machine powered by full water hydraulic, the large flow and high frequency proportional flow control valve that is necessary in the injection is studied in this project. Considering the physicochemical properties of water medium, hierarchical control structure of the valve ,interstage coupling form and structure parameters are optimum matched. The valve mouth shape, material matching and feedback form will be studied in this project to improve the control precision of the valve and restrain the effect of nonlinear factor such as hydrodynamic flow force, inertia force, frictional force and cavitation characteristics. The precise model of the whole system will be established, the coordinated control of pressure and velocity will be studied, and the method to restrain the system pressure shock will be proposed. The experimental platform will be built to verify the above theory. This project will lay a technical foundation for the development of die casting machine powered by full water hydraulic which has proprietary intellectual property rights , and also play a very important role in promoting the development of water hydraulic technology.

压铸是一种先进、高效的金属精密成型技术，广泛用于机电产品的制造。目前，压铸机主要由油液压驱动，存在污染、泄漏、易燃易爆等缺点。本项目提出一种全水液压驱动压铸机，同油压驱动相比，具有绿色环保，高温安全等突出优势。压射系统是决定压铸机性能好坏的关键，直接影响铸件的表面质量、轮廓尺寸和致密性等。本项目聚焦全水液压驱动压铸机压射系统，研究系统所需的大流量高频响比例流量控制阀，结合水的理化特性，确定阀的分级控制结构、级间耦合形式和结构参数的优化匹配；从阀口形状、材料配对、反馈形式等方面入手研究抑制液动力、惯性力、摩擦力和气穴特性等非线性的因素以提高阀的控制精度。建立压射系统的精确模型，研究压力和速度的分段协调控制及系统压力冲击的抑制方法；搭建试验平台，实验验证上述理论。项目将为水液压驱动压铸机这种具有我国自主知识产权的新装备的开发奠定技术基础，同时对推动水液压技术的发展具有重要意义。

全水液压驱动压铸机同油压驱动的相比，具有绿色环保，高温安全等突出优势。项目按照任务书的要求，对全水液压驱动压铸机的核心——压射系统——开展了系统深入研究，完成了规定的全部内容，主要成果如下：系统研究了高压大流量水压锥阀在空化作用下阀口液动力特性，获得了阀口不同参数对锥阀空化和液动力的影响规律；提出了一种适合压射系统工况的双U型非全周阀口，并研究了阀口参数对液动力的影响，参数优化后液动力得到了有效的补偿；建立了大流量水压比例插装阀精确的数学模型，设计了模糊PID控制策略。研制出水压比例先导阀和大流量水压比例插装阀的样机，其主阀通径为50mm，流量达到1100L/min（@压差=1MPa），响应时间为60 ms；搭建了纯水驱动压射系统模拟试验系统，提出了速度和压力复合控制策略，对水压比例流量阀在压射系统中的性能和控制策略进行了验证。上述成果为全水液压驱动压铸机的研制奠定了技术基础；气蚀对液动力影响的相关基础研究对水液压阀的设计具有普遍意义；同时，水压比例技术的研究促进了深海装备水液压技术的应用从开关控制迈向比例控制；高压大流量水压比例阀的研制成功引起行业的密切关注，被作为煤矿水液压支架数字智能化的核心部件而列入煤炭科工集团的重点项目。项目在International Journal of Heat and Mass Transfer、《液压与气动》等国内外核心期刊发表论文12篇，其中SCI检索4篇，EI检索3篇，获国际会议最佳论文1篇；申请专利6项，已授权专利4项；培养博士后、博士和硕士研究生10名，多名毕业生入选不同层次人才计划；同时主办570人参与的国际会议一次，参加国际会议两次；牵头制定水液压行业第一个标准《水液压系统通用技术条件》，该标准入选工信部2019年团体标准百强示范项目。