秸秆深埋还田开沟灭茬机设计与试验

秸秆还田是农作物秸秆综合利用最为直接的形式,深埋还田能打破犁底层、培肥地力,并提高土壤抗旱保墒能力。在秸秆深埋还田时,由于作物根茬未粉碎,深开沟的同时会出现大块土垡。秸秆深埋后还需对根茬和土垡进行二次粉碎,增加了作业成本。为满足秸秆深埋还田开沟灭茬碎土的需求,设计研制了一种集开深沟、碎土、灭茬等多道工序的用于秸秆深埋还田的开沟灭茬机。以导向铲入土深度、灭茬刀转速、灭茬深度为试验因素,机器的作业阻力和灭茬碎土率为试验指标,进行了三因素三水平正交试验。结果表明导向铲入土深度和灭茬深度对作业阻力有极显著影响,灭茬刀转速对灭茬碎土率有极显著影响。在开沟深度为35 cm时,导向铲入土深度、灭茬刀转速和灭茬深度分别为100 mm、340 r/min和60 mm时,开沟灭茬机的作业性能最好,作业阻力为21.6 k N、灭茬碎土率为96.3%、开沟深度稳定性为92.4%。试验表明该机具有很好的开沟、灭茬、碎土效果,该研究为秸秆深埋还田机具的研制和配备提供参考。

Design and experiment of combine machine for deep furrowing, stubble chopping, returning and burying of chopped straw

Abstract: Returning and deep burying of crop straw into soil is an effective way to utilize and recycle the resource of straw, to decrease pollution and increase soil fertility. Deep furrowing is the key operation of the technology. The burying quality of present machine is decreased for there is no stubble breaking device and large soil blocks are lifted together with the undetached stubbles, and the operation cost increases for the shattering of stubbles and soil blocks after straw burying. A combine machine for deep furrowing, stubble chopping, returning and burying of chopped straw was developed in this study to solve above problems. The machine thus combined the functions of stubble cleaning and furrow opening. The machine consisted of a furrowing plow, a guide shovel and a stubble breaking unit. The furrowing plow was designed to cut at different depths into the soil. Critical components of the machine, such as furrowing plow of beak type, shovel guide and stubble breaking unit, were designed to withstand the tillage resistance. The 3D (three-dimensional) models of shovel guide and furrowing plow were set up and the structural strength analyses were carried out using Solidworks and ANSYS software respectively. A gear reduction transmission system was designed to control the rotational speed of the smasher shaft from the PTO (power take off). Field performance evaluation test was carried out in Jilin Province. An orthogonal experiment of 3 factors with 3 levels was conducted to investigate the effects of depths of guide shovel, rotary speed of stubble breaking blade and depth of stubble breaking on tillage resistance and rate of stubble cutting and soil breaking. The depth of guide shovel was selected as 100, 150 and 200 mm; the rotary speed was set at 260, 300 and 340 r/min and the depth of stubble smasher was at 60, 70 and 80 mm respectively. Analysis of variance (ANOVA) showed that the rotary speed of stubble breaking blade had significant effect on the rate of stubble cutting and soil breaking at probability level of 1%; the depths of guide shovel and stubble breaking had significant effects on the resistance force at 1% level of significance as well. So, it could be inferred from the statistical analysis result that the rotary speed of stubble breaking blade had no influence on the tillage resistance, while the depths of soil cut of both guide shovel and stubble breaking influenced the resistance, and consequently affected the tillage power requirement of the machine. The evaluated results further showed that the optimum tillage resistance and the rate of stubble cleaning and soil breaking were 21.6 kN and 96.3% respectively at a rotary speed of 340 r/min and depths of the guide shovel and stubble cleaning of 100 and 60 mm respectively. Results of the strength analysis showed that the structural strength of the machine was adequate for the service condition. It could be concluded that the developed combine machine is efficient in deep furrowing, shattering soil, breaking stubble and burying chopped corn straw with a good operation quality.