【作者】 王晶；

【导师】 宫元娟；

【作者基本信息】 沈阳农业大学 ， 农业机械化工程， 2011， 硕士

【摘要】 玉米是我国主要的粮食作物、饲料和工业原料,在国民经济发展中占有重要地位。加强玉米生产,尽快提高玉米总产量,对国家粮食生产具有重要意义。玉米果穗具有双排籽粒的特点,基于这种生物特性而产生的对生种子栽培技术,是一种新型的玉米高产栽培技术。经过试验发现,对生种子栽培的双株玉米的生物特性完全相同,且双株均能正常产果。因此在相同的种植面积下,产量提高15%～20%。对生种子脱粒机是实现玉米对生种子栽培技术的关键设备,对该设备的试验研究具有现实意义。本文在综述玉米脱粒机现状与研究进展的基础上,对对生种子脱粒机进行理论分析及关键部件设计。对生种子脱粒机关键部件主要包括圆柱螺旋压缩弹簧、对辊夹持进给机构、钻具固定装置以及钻具等部分。然后,进行脱粒工艺参数试验研究。通过单因素及四因子二次回归正交试验,研究玉米果穗直径、果穗含水率、钻具直径、钻具角度对对生种子脱粒率和破损率的影响,建立数学模型,优化试验参数。主要研究结论如下。(1)对生种子脱粒机理论分析。对生种子脱粒机依靠一套完善的动力传动与减速系统,采用内脱式工作原理,将玉米果穗从内部破碎,把玉米果穗上并列成对的种子在小穗原基近穗轴处成对取下来,形成并列成对种子体。从机器本身结构看,通过受到对辊的夹持作用,同时又有柔性橡胶带的静摩擦力的作用,使得玉米果穗完成从进料斗的进料至传送过程,直至果穗芯部接触到钻具头部,进而进行钻具的切削脱粒过程。(2)对生种子脱粒机关键部件设计。设计圆柱螺旋压缩弹簧主要几何尺寸为：节距为3.68mm,外径为18mm,内径为12mm,高度为70mm；对辊夹持进给机构采用柔性橡胶带结构,在保证玉米果穗轴线与钻具轴线的对中性的同时,降低了玉米果穗破损率；钻具固定装置包括钻具底座和钻具套两部分,二者之间必须保证精确配合,从而保证钻具在高速运转过程中的平稳性；钻具结构包括钻头和钻柄两部分,钻头必须保证—定的刃度和角度才‘能进行切削,而钻柄则需要与钻具固定装置精确配合。(3)对生种子脱粒机单因素试验研究。确定钻具角度、钻具直径、果穗直径和果穗含水率4个为显著影响因素。在玉米果穗大头向下放入进料斗的前提下,钻具角度为60°、果穗平均含水率为35%时,能够达到较高的对生种子脱粒率。(4)对生种子脱粒机四因素二次回归正交试验研究。通过建立数学模型,利用多目标非线性优化理论与方法,确定玉米对生种子脱粒的最佳参数组合：果穗平均直径为39mm时,果穗含水率为44%,钻具直径为23mm,钻具角度为74°,此时对生种子脱粒率为43.85%,籽粒破损率为0.65%；果穗平均直径为42mm时,含水率为44%,钻具直径为24mm,钻具角度为72°,此时对生种子脱粒率为42.19%,籽粒破损率为0.91%；果穗平均为直径47mm时,含水率为44%,钻具直径为25mm,钻具角度为70°,此时对生种子脱粒率为42.01%,籽粒破损率为1.24%。更多还原

【Abstract】 Maize is China’s main grain crop, feed and industrial raw materials, which has an important position in national economic development. To enhance the maize production and to improve the total yield as soon as possible have a great significance on the national food production. The maize ear has the feature of pair seeds. The pair seeds cultivation technique, based on this biological properties, is a new type of maize high-yield cultivation techniques. Through the experiment, we can find that the maize grown from pair seeds is identical in biological properties and can produce fruit normally. In this way, the yield increase by 15%～20% with the same acreage. The maize pair seeds thresher is the key device for maize pair seeds cultivation techniques. Experiment for it has practical significance.Based on the review status and research progress of maize thresher, the maize pair seeds thresher was analysed theoretically and the key parts were designed. The key parts of maize pair seeds thresher mainly contained coil compression spring, grip-feed apparatus of double rollers, drill fixed apparatus and drill. Done with the design, the experimental studies were tested about the thresh parameters. The single factor tests and the quadratic orthogonal tests were experimented, and the effect on thresh percentage of pair seeds and damaged seeds of maize ear average diameter, maize ear average water content, thresher drilling tool diameter and drill angle was analyzed. The mathematical model was developed and the test parameters were optimized. The major conclusions were as follows:(1) Theoretical analysis of the pair seeds thresher. The maize pair seeds thresher relied on a set of system of power transmission and deceleration, which adopted the inner-thresh principle. The maize ear was broken from inside, and the pair seeds were taken down from the spikelet primordial. From the machine structure, the maize ear was clamped by the pair rollers and was affected by static friction of flexible rubber belt through the process of feed, transfer, access to the drill and drill.(2) Design of pair seeds thresher’s key parts. The main geometric parameters of the coil compression spring were determined. The pitch was 3.68mm, the external diameter was 18mm. the inner diameter is 12mm, the height is 70mm.The key part of the grip-feed apparatus of double rollers was flexible rubber rape. The neutral axis of the maize ear and drill was ensured and the goal of reducing the breakage of maize ear was achieved by adopted the rubber rape. The drill fixed apparatus contained drill base and drill sheath. The two parts must be matched exactly, and then the stability of the drill’s high speed process could be guaranteed. The drill contains drill edge and drill stem. The drill edge must be guaranteed a certain degree and angle to cut.. The drill stem and the drill fixed apparatus must be matched exactly. (3) Experiment of pair seeds thresher. The significant factors such as drill angle, thresher drilling tool diameter, maize ear average diameter and maize ear average water content were determined by single factor tests. Under the premise of the bulk of the maize ear down into the hopper, the drill angle was 60°and the ear average water content was 35%, a high percentage of pair seeds can be achieved.(4) Quadratic orthogonal experiment of pair seeds thresher. The mathematical model was developed. The optimal parameters of thresher were obtained through multi-goal non-linear optimizing method. When the average diameter of maize ear is 39mm, the ear water content is 44% and drilling tool diameter is 23mm and its angle is74°. When the maize ear average diameter is 42mm, the ear water content is 44% and the drilling tool diameter is 24mm and its angle is 72°. When the maize ear average diameter is 47mm, the ear water content is 44% and the drilling tool diameter is 25mm and its angle is 70°.更多还原