果园开沟施肥机开沟刀片理论与试验研究

发布时间：2018-05-21 04:36

本文选题：正弦指数曲线 + 组合型开沟刀片　；参考：《中国农业机械化科学研究院》2017年博士论文

【摘要】：机械化开沟施肥能够提高作业效率、降低人工劳动强度,是果园施肥作业的发展趋势。开沟刀片是开沟施肥机最重要的工作部件,目前存在功率消耗大、开沟深度不稳定等问题,无法满足果园开沟施肥的农艺要求。本文在分析现有研究成果的基础上,通过理论分析、模拟仿真和试验研究,设计出一种组合曲线型开沟刀片,探讨了刀片结构参数、作业参数与功率消耗和开沟质量的相互作用关系,揭示了其节能降耗微观机理,解决了果园开沟施肥机动力消耗大,开沟深度不稳定的问题。主要得到以下结论:(1)设计了一种"正弦指数曲线—圆弧"组合型开沟刀片。对组合曲线型开沟刀片进行了运动学和动力学分析,确定了刀盘转速、切土节距、刀片数量等主要技术参数;对开沟过程土壤切削机理进行研究,得出刀盘反转是深度开沟最适宜的开沟方式;通过对侧切面、正切面切土力学模型分析,建立了开沟刀片侧切刃参数、正切刃参数、运动参数与功率消耗的数学模型;以60Si2Mn作为刀片材料,遵循相应技术要求,以弯曲半径、弯折角、滑切角为变量,设计并加工了 15种结构不同的"正弦指数曲线—圆弧"组合型开沟刀片。(2)通过室内土槽试验,研究了 "正弦指数曲线—圆弧"组合型开沟刀片结构参数和工作参数对功率消耗和沟深稳定性的影响,在满足作业质量的前提下,结构参数对功率消耗的影响贡献由大到小为弯折角、滑切角和弯曲半径;对沟深稳定性的影响贡献由大到小为滑切角、折弯角和弯曲半径。采用非线性优化计算方法,确定了当弯折角为86.75°,弯曲半径为12 mm,滑切角为13.8°,前进速度为1.0 km/h、刀盘转速为200 r/min时,功率消耗和沟深稳定性取得最优值,并且认为刀盘转速200 r/min是正弦指数曲线型开沟刀片开沟作业的最佳转速。(3)利用光滑粒子流体动力学方法,采用修正的Drucker-Prager准则,建立了"土壤—开沟刀片"的三维动态仿真模型,对"正弦指数曲线—圆弧"组合型开沟刀片切削土壤的微观过程进行分析。研究表明,在开沟作业过程中,应力和应变随着开沟刀片与土壤接触面积和时间的增加而增大,在变化达到一定程度时,逐渐趋于稳定。选取了两种有代表性的工况进行仿真分析,得出了开沟过程功率消耗动态曲线图,揭示了土壤切削功率消耗微观机理。在开沟深度分别为400 mm和500 mm条件下,仿真模拟和土槽试验功率消耗误差在5%以内,且在转速200 r/min时功率有最小值,验证了仿真模型的正确性。(4)以开沟深度、刀盘转速和前进速度为试验因素,功率消耗和沟深稳定性为试验指标,对"正弦指数曲线—圆弧"组合型开沟刀片进行了田间试验。结果表明:开沟深度是影响功率消耗的最显著因素;前进速度是影响沟深稳定性的最主要因素。在两种开沟深度下,"正弦指数曲线—圆弧"组合型开沟刀片均表现出了比普通开沟刀片优良的性能。研究工作为开沟刀片节能降耗以及开沟机整机的优化设计提供了理论基础,对于促进我国果园管理机械的迅速发展具有重要意义。
[Abstract]:Mechanized ditching fertilization can improve the efficiency of operation and reduce the labor intensity. It is the development trend of the orchard fertilization operation. The opening blade is the most important working part of the furrow fertilizing machine. At present, there are many problems, such as high power consumption, unstable furrow depth and so on, which can not meet the agronomic requirements of the orchard opening and fertilization. On the basis of the theoretical analysis, simulation and experimental research, a combined curve type opening blade is designed. The interaction relationship between the parameters of the blade structure, the operating parameters and the power consumption and the quality of the ditch is discussed, and the micro mechanism of energy saving and consumption reduction is revealed, which has solved the large consumption of the maneuver force and the unstability of the furrow depth in the orchard. The main conclusions are as follows: (1) a "sinusoidal exponent curve circular arc" combined groove blade was designed. The kinematic and dynamic analysis of the combined curved groove blade was carried out. The main technical parameters, such as the rotating speed of the cutter disk, the pitch of the cutting soil, the number of blade and so on, were determined. The cutting mechanism of the soil in the process of opening the ditch was studied and the knife was obtained. Disc reversal is the most suitable opening method for deep furrow opening. Through the analysis of the mechanical model of the side cutting surface and the tangent surface, the mathematical model of the side cutting edge parameters, the tangent blade parameters, the motion parameters and the power consumption is established. The 60Si2Mn is used as the blade material and the corresponding technical requirements are followed, with the bending radius, bending angle and slip angle as variables. 15 kinds of "sinusoidal exponent curve - circular arc" combined opener have been designed and processed. (2) the influence of the structural parameters and working parameters of the "sinusoidal exponent curve - circular arc" combined type opening blade on the power consumption and the depth of the ditch is studied through the laboratory test. The structure parameters are satisfied on the premise of satisfying the quality of the operation. The contribution of power consumption is from large to small to bending angle, sliding angle and bending radius, and the contribution from large to small to small to slip angle, bending angle and bending radius. The nonlinear optimization method is used to determine when the bending angle is 86.75 degrees, the bending radius is 12 mm, the slip angle is 13.8, the forward speed is 1 km/h, the cutter disk turns. When the speed is 200 r/min, the optimal value of power consumption and ditch depth stability is obtained, and the speed of 200 r/min is considered to be the best speed for the groove opening operation of the sinusoidal exponential curve. (3) using the smooth particle hydrodynamics method and using the modified Drucker-Prager criterion, a three-dimensional dynamic simulation model of the "soil - ditching blade" is established. The microcosmic process of cutting soil with the "sinusoidal exponential curve circular arc" combined type opening blade is analyzed. The study shows that stress and strain increase with the increase of the contact area and time of the cutting blade and the soil during the opening process, and gradually tend to be stable when the change reaches a certain range. Two representative types are selected. The dynamic curve diagram of the power consumption in the opening process is obtained. The micro mechanism of the consumption of soil cutting power is revealed. Under the conditions of 400 mm and 500 mm respectively, the power consumption error of simulation and soil tank test is less than 5%, and the power has the minimum value at the speed of 200 r/min, which verifies the correctness of the simulation model. (4) a field experiment was conducted on the test factor of the opening depth, the rotating speed and the forward speed of the cutter head, the power consumption and the depth of the ditch, and the field experiments were carried out on the "sinusoidal curve circular arc" combined open groove blade. The results showed that the depth of the ditch was the most significant factor affecting the power consumption; the forward velocity was the most important factor affecting the depth of the ditch. Under two kinds of furrow depth, the combination of "sinusoidal exponent curve and arc" combined type opening blade shows better performance than ordinary trenching blade. The research work provides a theoretical basis for saving energy and reducing consumption of opening blade and optimizing the whole machine for the opening machine. It is important to promote the rapid development of the orchard management machinery in China. Significance.
【学位授予单位】：中国农业机械化科学研究院
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S224.2

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