| 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. |
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