Research And Trial-manufacture Of Straw Returning And Tillage Machine For High Stubble Paddy Field

Rice is one of the major food crops in china, most of rice is cultivated in the Yangtze river basin, northeast and southern part of China. As the main producing area of rice, the Yangtze river basin usually has various multiple cropping of cropping systems, including rape-rice, wheat-rice, green manure-rice, the double cropping of rice, triple-cropping of rice and so on. Rice is planted immediately after the harvest of the previous crop. Farmer must cultivate the soil of paddy field quickly, in transitory and busy farming season. However the residual stalk of previous crop has led to great difficulties for paddy fields tillage. The research now is focused on the high-efficiency tillage to solve the straw returning to the paddy fields. Recently it is considered to be an important part in studying the sustainable production and the mechanization planting of rice.This paper aimed to achieve the high-efficiency stalk returning and tillage in paddy fields, a kind of tillage machine for paddy field, which has two helical rollers was developed in this study, carried out the general design, key parts design and analysis of the machine. The main research contents are the following aspects:(1) Based on the previous research of the straw returning and paddy field tillage machine in China and abroad, designed a paddy fields straw returning and tillage machine with two spiral roller,which is suitable for the high stalk residues. Analysed the working principles and working process, and put forward the overall performance index parameters and structure parameters, analysed selection of the matching power machine.(2)Testing of bending and axial compression on the mature rice stalk, maked an analysis the differences of mechanical performance in different growth parts of rice stalk. The test results showed that the diameter of rice stalk increase in turn, from top to root, mechanical performance also increase in turn, the maximum bending destructive of the stalk upper and lower part respective for6.07N and9.64N, the maximum compression destructive of the stalk upper and lower part respective for46.96N and69.35N, the required force by compression damage is much larger than it by bending damage at the same growth parts of the stalk.(3) Designed and analysed the key parts of the machine, including the power transmission system, working blade roller and its spiral horizontal blade, pressure stalk device, anti-wind grass device and the soil levelling device. Maked a focused analysis on the structure parameters and kinematic parameters of the spiral blade roller inclusive the spiral horizontal blade, and the analysis for arrangement of the left and right spiral horizontal blade on two curving blade. In the cut soil pitch to meet3～6cm, based on the analysis of the motion simulation, determined the working velocity range of this machine and articulated power machine is0.835～1.67m/s.(4) Completed the establishment of a solid model of the machine and its components based on Pro/E software, and analyzed the global interference checking and motion simulation. The normal cutting condition about the forward velocity region of the tractor, when the rotational speed of the tractor power output is720r/min.Analysed the influence of units forward speed on the quality of work when power machine provide the constant rotational speed.(5) Carried out numerical simulation of the blade roller cutting soil based on ANSYS/LS-DYNA, a display dynamics analysis software. Simulated the soil deformation, the cutting resistance and the power consumption in the process of cutting soil. Get the maximum cutting force is14104N, and maximum power consumption is6.4KW,while the blade roller rotating speed is300r/min and the forward velocity is1.1m/s.(6) The performance test of the developed straw returning and tillage machine in paddy field, the average of rice straw residual height is300mm in stubble paddy field. The results of field performance experiments indicated that the cultivator could complete many functions at one time such as covering the high straw, crashing earth, leveling off the surface etc, and the performance indexes of cultivator were as follows:straw coverage rate was94.19%, surface roughness after rotary tillage was25.0mm. The working quality of cultivator accorded with agronomic demand of rice seeding and transplanting.