拖拉机液压系统多路阀结构设计及优化

发布时间：2018-07-22 11:50

【摘要】：拖拉机是我国农业机械中最主要的农机之一,液压系统作为一种传动技术,成为拖拉机的重要组成部分,而多路换向阀作为拖拉机液压系统中最核心的控制元件,其主要作用是控制多个执行机构动作,它决定了拖拉机的整机工作性能。但是目前国产拖拉机液压系统中多路换向阀存在泄漏量过多、压力损失严重、换向操纵力过大等问题,严重制约了多路换向阀以及农业机械装备的发展。针对上述问题,本课题以1002/1202系列履带拖拉机液压系统多路换向阀为研究对象,综述国内外多路换向阀发展现状,提出一种特殊形式的新型节流槽四位滑阀设计方案;采用理论分析、数值模拟和试验验证相结合的方法进行深入研究:构建新型节流槽的数学模型,采用粒子群优化算法对节流槽进行结构优化,得到节流槽的最优设计参数;采用Solidworks软件建立多路换向阀几何模型,基于计算流体动力学原理,利用Fluent流体仿真软件进行流体仿真分析,结果表明:新阀与原阀相比流道局部最大速度降低,压力损失减小,泄漏量也有所降低,能够使多路换向阀在工作过程中受到的稳态液动力减小,从而使得阀芯受到的最大稳态液动力小于换向操纵力,增强多路阀的工作平稳性;根据行业标准,制定试验方案并设计试验系统原理图,利用综合液压试验台对多路换向阀开展相关性能试验,试验表明:试验数据和仿真数据基本吻合,验证流场仿真的准确性和四位滑阀节流槽结构设计的合理性。本文通过对拖拉机液压系统多路换向阀四位滑阀节流槽结构开展优化设计,能够改善多路换向阀的阀口流量特性,提升整机工作性能。同时,采用的流场仿真和试验方法能够指导多路换向阀以及其他液压元件的设计,为相关产品的开发提供一定的数据支撑与理论指导。
[Abstract]:Tractor is one of the most important agricultural machinery in our country. As a transmission technology, hydraulic system becomes an important part of tractor, and multi-way reversing valve is the core control element in tractor hydraulic system. Its main function is to control the action of multiple actuators, which determines the working performance of the tractor. However, there are many problems in the hydraulic system of domestic tractor, such as excessive leakage, serious pressure loss and excessive reversing force, which seriously restrict the development of multi-way reversing valve and agricultural machinery equipment. In view of the above problems, this subject takes 1002 / 1202 series crawler tractor hydraulic system multi-way reversing valve as the research object, summarizes the domestic and international development situation of the multi-way reversing valve, and puts forward a special design scheme of a new type of four-position slide valve with throttle slot. Theoretical analysis, numerical simulation and experimental verification are used to study deeply. The mathematical model of new throttle is constructed, and the structure of throttle is optimized by particle swarm optimization algorithm, and the optimal design parameters of throttle are obtained. Based on the principle of computational fluid dynamics and fluent fluid simulation software, the geometry model of multi-channel reversing valve is established by Solidworks software. The results show that compared with the original valve, the local maximum velocity of the new valve decreases and the pressure loss decreases. The leakage rate is also reduced, which can reduce the steady state hydraulic power of the multi-way reversing valve in the course of operation, so that the maximum steady state hydraulic power of the valve core is less than that of the reversing operation force, so as to enhance the working stability of the multi-way valve; according to the industry standard, The test scheme was made and the schematic diagram of the test system was designed. By using the comprehensive hydraulic test bench, the related performance tests of the multi-way directional valve were carried out. The test results showed that the test data were basically consistent with the simulation data. The accuracy of flow field simulation and the rationality of the structure design of four-position slide valve throttle are verified. In this paper, by optimizing the structure of four position slide valve throttle slot in the hydraulic system of tractor, the flow characteristics of the valve orifice can be improved, and the working performance of the whole machine can be improved. At the same time, the flow field simulation and test method used can guide the design of multi-way reversing valve and other hydraulic components, and provide some data support and theoretical guidance for the development of related products.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S219.032.1

【参考文献】