微耕机刀辊的优化设计及切土性能研究

发布时间：2018-01-19 12:39

本文关键词： 旋耕弯刀旋耕刀辊几何参数切土性能数值模拟　出处：《西南大学》2017年硕士论文　论文类型：学位论文

【摘要】：微耕机主要用于水、旱田耕整、田园管理和设施农业等耕耘作业,它可以直接用驱动轮轴驱动旋转工作部件,即刀辊。刀辊是微耕机的耕作部件,即微耕机的刀具。微耕机的作业质量、操作性、振动和噪音、能量消耗等在很大程度上取决于刀辊的设计制造及其与切土参数的匹配。刀辊由旋耕弯刀和刀轴组成,弯刀按一定排列方式安装在刀轴上。旋耕弯刀的正切部和侧切部担负切土工作,其几何参数直接影响刀辊及微耕机的工作性能。目前,微耕机刀辊的选型和设计主要基于对传统耕耘机刀辊几何和切土参数的借鉴和改进,依赖于经验和实际试验。各微耕机生产企业所配刀辊(主要是旋耕弯刀)的形状、结构和切土参数差异较大,整机性能匹配不尽合理,缺乏理论指导。针对微耕机刀辊选型和设计理论的不完善,以及旋耕弯刀参数设计和选择标准不完善等问题,本文对旋耕弯刀几何参数建模、背角建模和旋耕刀辊排列设计,以及旋耕弯刀和刀辊的动力学仿真切土试验等关键技术进行了研究,设计并优化了微耕机刀辊的形状、结构和切土参数,形成了微耕机最优刀具选型和设计方法。本研究能为微耕机刀辊设计和整机性能匹配提供理论依据。本文的主要研究结果包括:(1)建立了旋耕弯刀参数化模型和背角数学模型,在此基础上研究了正切刃包角与背角的关系,分析了旋耕弯刀弯折角与背角的关系。结果表明,包角和弯折角对背角的影响显著,都呈正相关,对研究旋耕弯刀切土性能有重要影响。(2)运用有限元分析软件ANSYS/Workbench对旋耕弯刀进行静力分析,得到旋耕弯刀受力时的等效应力应变及总变形分布情况,从理论上验证了基于旋耕弯刀参数模型优化设计的旋耕弯刀的合理性。(3)通过基于SPH算法的仿真切土方法,分析了文中旋耕弯刀的切土性能,以及对比分析了Alpha角对旋耕弯刀切土性能的影响,为研究旋耕弯刀几何参数与其切土功耗之间的影响关系提供了理论依据。(4)对旋耕刀辊进行优化设计,得到优化旋耕刀辊模型,并通过基于SPH算法的仿真切土方法,对比研究了优化旋耕刀辊与传统旋耕刀辊在切削土壤时动力学性能和能量消耗的差异。结果表明,相对于传统旋耕刀辊,优化旋耕刀辊的切土性能更优,其切削功率比传统旋耕刀辊减小10%。(5)对比分析了两组刀辊的仿真计算功率与估算功率。结果表明,两者之间的相对误差较小,说明基于SPH算法的切土仿真用于旋耕刀辊切土性能研究是可行的。
[Abstract]:Micro-tillage machine is mainly used for ploughing work such as water, dryland plowing, field management and facility agriculture. It can drive rotary working parts directly by driving wheel shaft, that is, knife roll, which is the tillage part of micro-tillage machine. The cutting tools of the micro-tillage machine. The working quality, operation, vibration and noise of the micro-tillage machine. The energy consumption depends to a great extent on the design and manufacture of the cutter roller and its matching with the soil cutting parameters. The curved knife is arranged on the cutter shaft in a certain arrangement. The tangent part and the side cut part of the rotary tiller are responsible for cutting soil, and its geometric parameters directly affect the working performance of the cutter roll and the micro-tiller. At present. The selection and design of knife roll of micro-tillage machine is mainly based on the reference and improvement of the geometry and soil cutting parameters of the traditional cultivator tool roll. Depending on experience and practical test, the shape, structure and soil cutting parameters of the knife roll (mainly rotary crochet cutter) of the micro-tiller production enterprises are different greatly, and the performance matching of the whole machine is not reasonable. Lack of theoretical guidance. Aiming at the imperfect selection and design theory of the tool roll of micro-tillage machine, as well as the imperfect design and selection standard of rotary crochet cutter, this paper models the geometric parameters of rotary crochet cutter. The key technologies, such as back angle modeling, roll arrangement design, and dynamic simulation soil cutting test of rotary crochet and cutter roll, are studied. The shape, structure and soil cutting parameters of tool roll are designed and optimized. The optimal tool selection and design method of micro-tillage machine is formed. This study can provide theoretical basis for tool roll design and performance matching of micro-tillage machine. The main results of this paper include: 1). The parametric model and the back angle mathematical model of rotary crochet are established. On this basis, the relationship between the tangential edge angle and the back angle is studied, and the relationship between the bending angle and the back angle of the rotary crochet is analyzed. The results show that the envelope angle and the bending angle have a significant effect on the back angle, both of which are positively correlated. It has an important influence on soil cutting performance of rotary tiller. 2) static analysis of rotary crochet is carried out by using finite element analysis software ANSYS/Workbench. The distribution of equivalent stress, strain and total deformation of rotary curved knife is obtained. The rationality of the rotary crochet based on the optimal design of the parameter model of rotary tiller is verified theoretically. The soil cutting performance of the rotary crochet is analyzed by using the simulation soil cutting method based on SPH algorithm in this paper. The effect of Alpha angle on soil cutting performance of rotary crochet was analyzed. This paper provides a theoretical basis for the study of the relationship between the geometric parameters of rotary tiller and the power consumption of cutting soil. (4) the optimal design of rotary tiller roller is carried out, and the model of rotary tilling cutter roll is obtained. Through the simulation soil cutting method based on SPH algorithm, the difference of dynamic performance and energy consumption between the optimized rotary tiller roller and the traditional rotary tiller roller in cutting soil is compared. Compared with the traditional rotary tiller roll, the soil cutting performance of the rotary tiller roll is better. Its cutting power is 10% less than that of the traditional rotary tiller. (5) the simulation calculation power and the estimated power of the two groups of tool rollers are compared and analyzed. The results show that the relative error between the two groups is relatively small. It is feasible to use the soil cutting simulation based on SPH algorithm to study the soil cutting performance of rotary tiller roller.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S222

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