【作者】 王庆；

【导师】 鲁植雄；

【作者基本信息】 南京农业大学 ， 农业机械化工程， 2010， 硕士

【摘要】 近年来,我国农业机械化事业迅速发展,农机装备总量、农机作业水平、先进技术应用水平不断提高,对促进粮食增产、农民增收、农业增效发挥了重要作用。轮式拖拉机是实现农业机械化和现代化不可缺少的重要动力机械,随着新兴科学技术的不断发展,采用机电液一体化技术是拓宽拖拉机功能、提高其技术性能以及解决其所面临诸多技术难题的最佳选择方案,并且已经成为现代拖拉机的主要技术发展趋势。本文选择了某一中等马力的轮式拖拉机为研究对象,设计一套电控液压动力转向系统的机械和液压部分。该套转向系统对于改善轮式拖拉机的操纵性、降低驾驶员的劳动强度具有重要意义。论文的主要工作包括：分析了轮式拖拉机转向系统的发展过程,以及各种转向系统的特点及其工作原理,介绍了所设计的电控液压动力转向系统的结构及其工作原理。根据车辆的理想转向特性,设计了一套新的轮式拖拉机的转向机构,在所选轮式拖拉机的结构参数的基础上,确定了该套转向机构主要组成部分的结构尺寸,利用Solidworks软件支持鼠标动态拖动的功能,对所设计的转向机构进行了运动模拟,从而得到了优化后的转向机构的其余构件的结构尺寸。利用Matlab软件得到了所设计的转向机构的转向特性曲线。分析了轮式拖拉机转向系统的力学特性,计算得到转向系统的工作时要能承受的最大阻力矩。采用虚拟样机技术,应用Adams软件对所设计的转向机构进行了动力学分析,得到转向机构工作时液压缸要能产生的最大工作推力。通过最大工作推力完成了转向动力缸的设计。至此,转向机构各组成部分的结构参数设计完毕,应用Pro/E软件建立了转向机构的三维模型,并进行了运动模拟仿真,证明了机械部分设计的正确性。应用Ansys软件,把通过Adams仿真得到的力作为边界载荷条件施加在油缸活塞杆上,对活塞杆进行有限元分析,得出活塞杆在受力最大时刻的应力应变分布情况,为活塞杆材料的选择等提供了可靠依据。设计了电控液压动力转向系统的液压系统,绘制了液压系统原理图,对液压系统的各个组成元件的结构和工作原理进行了介绍,对液压系统静态特性进行了分析。基于Amesim软件建立了液压系统的仿真模型,验证了模型建立的正确性,并对液压系统动态特性进行了仿真分析。以学校的液压实验室为基础,搭建了液压系统的实验平台,介绍了所选用传感器的工作原理和基于Labview虚拟仪器技术的数据采集设备。得到了实验数据和图形,验证了液压系统设计的正确性。最后,对本论文的研究工作和成果进行了总结,展望了下一步的研究工作。更多还原

【Abstract】 Recently, total amount of farm machinery and equipment, the level of agricultural machine works,and the increasing level of advanced technology applications, because of the rapid development of China’s agricultural mechanization. They are very important for the promotion of grain production, increasing the income of peasants and the benefit of agricultural.Wheeled tractor is important and indispensable power machinery for achieving mechanization and modernization of agriculture, with the continuous development of new science and technology, mechanic-electro-hydraulic integration technology is the best option in broadening the tractor’s ability, improving their technical performance and solving the numerous technical difficulties which they are facing, and has become a major technology trends for modern tractor.This paper selected a medium-horsepower wheeled tractor as the research object, and designed the mechanical and hydraulic parts of an electronic hydraulic power steering system. This set of steering is of great significance for improving manipulative and reducing the driver’s labor intensity. The main work includes:Analyze the development process of the wheeled tractor’s steering system, various steering system’s characteristics and working principle. Introduce the structure and working principle of the electronic hydraulic power steering system that I devised. According to the ideal characteristics of the vehicle steering, I have designed a new steering mechanism for wheel tractor. On the basis of the structural parameters of wheeled tractor that I selected, I definite the structure size of the main components of this set of steering mechanism. Make use of Solidworks software’s which it supports dynamic drag the mouse, simulate the steering mechanism’s movement, and so obtain the structure size of the remaining elements of optimized steering mechanism. Get the steering characteristic curves of the steering mechanism by taking advantage of Matlab software. Analyze mechanical properties of wheeled tractor’s steering system, calculate what the maximum resistance torque the steering system must be able to withstand when it working. Using virtual prototyping technology,carry out steering mechanism dynamics analysis by Adams software. Get the maximum thrust that steering hydraulic cylinders must be able to generate when it working. Complete the design of steering cylinder by the maximum thrust. Thus, the design of the structural parameters of the various components of Steering mechanism is completed. Establish the three-dimensional model of the steering mechanism by Pro/E software, and conduct a simulation exercise, prove the correctness of the design of the mechanical parts.Apply the simulation result which can be available from Adams to the cylinder and make a FEM analysis. So we can see the distributing situation of stress and strain.Designed hydraulic system of a electronic hydraulic power steering system, draw the Schematic drawing of the hydraulic system. The various components of the hydraulic system components, structure and working principle are introduced; analyze the Static characteristics of the hydraulic system. Establish the simulation model of the hydraulic system based on Amesim software, verify the correctness of the simulation model, conducted a simulation analysis of dynamic characteristics of hydraulic systems.Based on hydraulic laboratory of our school, set up the experimental platform of the hydraulic system, make a description of the selected sensor’s working principle and Data Acquisition Equipment based on Labview Virtual Instrument. Obtained experimental data and graphics, Verify the correctness of the hydraulic system design.Finally, summarizes the research work and achievements of this paper, looking for the next step of the research work.更多还原