【作者】 吴明亮；

【导师】 汤楚宙； 官春云；

【作者基本信息】 湖南农业大学 ， 种子科学与工程， 2008， 博士

【摘要】 我国是油菜生产大国,油菜常年种植面积居世界第一位,南方冬油菜区是我国的油菜主要产区,其种植手段严重落后,劳动强度大,经济效益低。改变目前油菜种植方式的唯一途径就是机械化。而油菜种植的关键技术是控制基本苗数量和田间排水畅通,涉及到机械上即为排种系统和开沟系统。然而,目前针对油菜播种的排种器还不是很成熟,排种精度难以控制;而开沟机市场上较多,大都属于工业用产品,大功率,机体重,价格昂贵,难以配套到农田作业。尤其是对机具与土壤的相互作用的理论研究很少,为此本研究针对油菜种植机械的关键部件开沟系统和排种系统进行理论研究,并设计制作了试验研究载体2BYF-6型油菜免耕直播联合播种机。该理论与试验研究为今后设计同类型免耕直播播种机提供理论依据。通过对油菜籽粒的物理机械特性的测定及对偏心轮型孔轮式排种器的排种机理进行分析,得到了设计排种系统的基本参数。借助Solidworks软件对排种系统核心部件—排种器进行结构设计和仿真,进一步优化排种器的结构参数,最后通过台架试验和田间播种试验验证。试验结果表明该排种系统能顺利完成油菜播种的要求。开沟器是2BYF-6型油菜免耕直播播种机的关键部件之一,本研究首先借助matlab优化工具箱对旋耕开沟刀盘进行结构优化设计,初步确定了刀盘结构参数,以此为基础,从运动动力学的角度建立起开沟刀盘在土壤中的运动模型。进而研究在刀片作用下的土粒受到切土、运土、抛土三个连续过程中的运动动力学数学模型,结果表明:土粒在运土及抛土阶段时,其速度和加速度及抛土阶段的横向抛土宽度不仅与旋耕刀盘的结构尺寸R_i,R_l,φ₀,δ和运动参数ω有关,还与土壤的物理机械性质f,k,土壤在刀片正切面上的运动方向θ有关。当旋耕刀盘体结构及运动参数确定后,土粒的运动速度和加速度主要与土粒在刀片正切面上的运动方向θ角及土粒受到刀片正切面支撑力与土粒质量比值系数k（土壤的物理机械性质）有关。最后借助Maple软件对相应数学模型仿真,进一步确立相关参数的影响权重。从被抛起土粒与挡土板相碰撞为前提,建立了土粒能与挡土板碰撞的条件,得到了挡土板材料、形状,安装位置对土粒最终抛向厢面的影响关系。以实现覆土均匀、细碎设计试验进行免耕播种机开沟性能试验研究,利用单因素、多因素正交试验,分别考查机具结构,土壤物理机械性质对开沟覆土的影响,从试验的角度验证了理论分析的正确性。更多还原

【Abstract】 Our country is a large rape producer,whose average plant area keeps the biggest in the world all the time.The southern winter rape area is the main rape producing area of our country,with gravelly fall behind cultivating means,big working intensity and low economic effect. Mechanization is the only way to change the present cultivating means.The key technique in rape cultivating is to control the fundamental seed quantity and keep smoothly drainage in the field,the two of which involves the seedling system and the ditching system in machinery.However,the present seedmeter used in rape cultivating is still immature and the seedling precise is hard to control;while the ditcher in market are numerous,most of which belongs to industrial product with high power,heavy weight,and high cost which is unsuitable for field working.Especially with the scarce theoretical research in the interaction between machine and soil,aimed at the key part of the rape mechanization cultivating machinery,this research has carried on certain theoretical study in the seedling system and the ditching system and designed the 2BYF-6 type non-cultivated combined rape seeder.Through this,it has provided certain theoretical basis for designing such type of non-cultivated combined rape seeder.The fundamental parameter of the designed seedling system is calculated through test on physical machinery property of the rape seed and analysis of seedling principle on the Socket hole-wheel seedmeter.By use of the Solidworks software,the structural parameter of seeder is optimized through structural designing and simulating of the seeder which is the core part of seedling system,and is finally tested by lab experiments and field seedling experiments.The results show that this seedling system can satisfy the smoothly seedling requirement.Ditcher is one of the key parts of the 2BYF-6 type non-cultivated combined rape seeder.By means of the Matlab optimizing tool case,this research first set the knife disk structure parameter by structural optimizing design of the ditching knife disk.On basis of this,the motion model of ditching knife disk in soil is established from the Kinetics angle so as to study the mathematic model in kinetics of the soil,which has gone through the effect of knife in 3 continuous processes of cutting soil,moving soil,and throwing soil.The results show that while moving the soil,its speed and acceleration are connected not only with the structure dimension R_i,R_l,ψ₀δof Rotary knife and the motion parameterδ,but also with the fiscal machinery property f,^k of soil and the motion direction of soil on the tangential side of the blade.With the rotary knife structure and motion parameter set,the speed and acceleration of soil become mainly connecting with the motion direction angleθof soil on the tangential side of the blade and the ratio parameter k of its support on the tangential side of the blade（the fiscal machinery property） to its mass.Finally,by using of Maple software to simulate the related mathematical model,the effect weight of each related parameter is further decided.By taking premises of the collision between the tossed soil and blocking soil board,the condition of collision between them is set,thus gets the effect of the material,form,installation location of the blocking soil board on toss of soil.In realization of evenly covered and smashed soil piece test,the study on ditching property of non-cultivated seeder is carried out by using mono-factor and multi-factor orthogonal test to examine the effect of machinery structure and fiscal machinery property on ditching and covering, through which,the correctness of theoretical analysis has been verified from the testing angle.更多还原