【作者】 卢彩云；

【导师】 李洪文；

【作者基本信息】 中国农业大学 ， 农业机械化工程， 2014， 博士

【摘要】 玉米地免耕播种小麦时,由于秸秆量大、秸秆粗大、韧性强,机具通过性差。现有动力驱动式防堵技术虽然在防堵方面有了很大改进,但仍存在问题。本文在研究国内外免耕防堵技术基础上,开发了一种滑板压秆旋切式防堵技术,并设计了相应免耕防堵装置,并配置与之配套的防堵开沟装置。通过室内特性试验研究和理论分析,确定各部件关键参数。在此基础上,进行样机试制和田间试验。主要研究结论如下：(1)针对现有动力驱动式免耕防堵装置转速高导致动力消耗大,振动大导致安全性差,动土量大,土壤破坏严重及残茬随高速旋转的刀片向后抛,再次落在种带上影响小麦出苗和幼苗生长等问题,基于支撑切割原理,开发了一种滑板压秆旋切式防堵技术,并设计了相应防堵装置,秸秆被切割时,滑板压住秸秆形成有支撑切割,同时防止秸秆向后飞溅影响出苗。本装置转速低、土壤破坏少、播种质量高。(2)根据滑板压秆旋切式防堵装置支撑切割秸秆防堵思路,开展了室内玉米秸秆切割特性试验。研究表明：①秸秆直径、含水率一定时,切刀质量越大,所需临界速度越小,秸秆被切断所需临界动能相同；②秸秆直径一定时,所需临界动能随秸秆含水率增大,表现出先增大后减小的趋势,秸秆含水率为50%～60%时,临界动能最大。(3)为避免秸秆在滑板前方或底部堆积导致堵塞,开展了室内防堵装置对秸秆的导流特性试验,主要研究滑板对秸秆的导流特性,即秸秆顺利通过滑板的必要条件,受力分析得到与之密切相关的参数：秸秆与滑板摩擦系数及秸秆与土壤摩擦系数,通过试验对比Q235、不锈钢、木材和塑料的导流特性,确定Q235为最佳滑板材料。(4)对滑板压秆旋切式防堵装置进行结构和运动学分析。应用Ansys进行静力学分析,分别得到关键部件旋切平面刀和滑板各方向应力和等效应力,在此基础上对滑板压秆旋切式防堵装置切割过程进行深入分析,将切割过程分为下支撑切割、上下联合支撑切割和上支撑切割三个过程,得到每个过程切割长度L、滑切角τn及其变化规律和秸秆受力模型。(5)对与滑板压秆旋切式防堵装置配套使用的防堵开沟装置进行理论和试验研究,防堵开沟装置由双圆盘施肥开沟器和锄铲式播种开沟器组成。确定了双圆盘开沟器切断或推开秸秆、锄铲式开沟器铲尖位于双圆盘开沟器之间等多重防堵,防堵能力强；确定了双圆盘开沟器沟底宽度、开沟宽度和沟型模型及锄铲式开沟器排种特性和回土特性；确定了种肥开沟器配置关系,前进方向距离范围满足R/2<L<R,竖直方向满足H=h1-h2,横向满足W=d1/2,种肥间距满足(6)在以上理论和试验分析基础上,确定滑板压秆旋切式防堵装置和防堵开沟装置各部件关键参数和配置参数,样机试制完成后进行田间试验。试验结果表明：种肥平均深度及种肥间距分别为6.68cm和4.53cm,土壤平均扰动量20%,地轮滑移率分别为4.6%和3%,播种带上秸秆和根茬切断效果好,小麦出苗好。分别与带状旋耕和条带粉碎免耕播种机进行对比试验表明,安装滑板压杆旋切式防堵装置的免耕播种机动土量小,出苗均匀,刀具转速低。更多还原

【Abstract】 Due to large amount of straw cover and straw of bulk and strong toughness, the planter has a bad performance in anti-blocking when wheat is planted in the field with maize straw cover. Exsiting power-driven anti-blocking technology has great improvement in anti-blocking, but still has problems. Based on the research of no-till anti-blocking technology at home and abroad, a technology of rotary cutting with slide plate pressing straw was put forward, and relevant device was developed and anti-blocking opening device matched to anti-blocking device was configurated. Key parameters for each component were determined by experimental research and theoretical analysis. On this basis, prototype was trial-produced and tested. The main results are as follows:(1) According to the problems that power-drived no-till anti-blocking device has high rotary speed, large power consumption, serious vibration and poor safety, large amount of soil disturbance and damage, and stubble cut by blade is thrown into seed bed and affects wheat emergence, based on support cutting, a technology of rotary cutting with slide plate pressing straw was put forward, and relevant device was designed. When straw was cut, slide plate pressed the straw and straw was support cut, at the same time, the straw was avoided flying back and affecting emergence. The device had low rotary speed, less soil degradation and good seeding quality.(2) According to the idea of support cutting on anti-blocking device of rotary cutting with slide plate pressing straw, laboratory experiment was designed. The results showed that:①When straw with certain diameter and moisture was cut, cutting speed was declined with blade weight increasing, and the same straw needs the same cutting kinetic energy;②when straw with certain diameter was cut, the cutting kinetic energy was first increased then decreased with straw moisture increasing. The cutting kinetic energy reached to highest when the straw moisture was50%or60%.(3) To avoid straw was accumulated in front of and at the bottom of slide plate and blocked, laboratory experiment was developed to test river diversion of anti-blocking device on straw. River diversion of the slide plate that straw passed slide plate successfully was tested. The related parameters include friction coefficient between straw and slide plate, and friction coefficient between straw and soil. Comparison river diversion of Q235, stainless steel, wood and plastic showed that Q235was the best material of support plate.(4) Geometric modeling and kinematics model of anti-blocking device of rotary cutting with slide plate pressing straw were analysed. Statics analysis by Ansys got stress in each direction and equivalent stress of blade and slide plate.On the basis, deep analysis of cutting progress of the device was got, and the cutting progress was devided into three parts, including cutting with support underneath the blade, cutting with support both underneath and above the blade, and cutting with support above the blade. Cutting lenghth L, force analysis model and variation of slip cutting τn for each part were derived.(5) Matched to anti-blocking device of rotary cutting with slide plate pressing straw, anti-blocking opening device was designed, included double-disc fertilizing opener and hoe seeding opener. Multiple anti-blocking methods such as double-disc opener cut or bypassed straw, and the tine of hoe opener was between two discs, which ensured good anti-blocking ability. The models of groove width d1, opening width df and furrow shape for double-disc opener, and the characteristics of seeding and soil covering for hoe opener were determined. Base on above, the configuration of double-disc opener and hoe opener was confirmed:the distance between double-disc opener and hoe opener in moving, vertical and horizontal direction was R/2<L<R, H=h1-h2and W=d1/2separately. The distance between seeds and fertilizers was30mm(6) Based on the theoretical and experimental analysis, key parameters and configuration parameters for each component on anti-blocking device of rotary cutting with slide plate pressing straw and anti-blocking opening device were determined. After produced, prototype was tested in the field. The result showed that:the average depth of seeds and fertilizers were2.59cm and6.68cm respectively, and the distance between seeds and fertilizers was4.53cm; average soil distanbance was20%, and actual opening width was higher than theoretical opening width, however, the width was much lower than the opening width made by strip rotary anti-blocking device; ground wheel slid was4.6%and3%, respectively; there was a good performance of stubble cutting on crop bed and good emergency performance. Compared with zonal rotary and strip chopping no-till planter respectively, no-till planter of rotary cutting with slide plate pressing straw has less disturbed soil, even emergence and lower rotary speed of blade.更多还原