【作者】 张宏；

【导师】 杨有刚；

【作者基本信息】 西北农林科技大学 ， 机械设计及理论， 2012， 硕士

【摘要】 不合理的松耕方法，会破坏土壤结构，降低土壤的透气、透水性，消灭了土壤中的蚯蚓等有益生物，因此，保护性耕作技术条件下的土壤松耕，是不引起上下土层过度翻转的耕作方式，土壤层只松不翻是其关键所在。但是，到目前为止，各种表土处理方法和机具，如旋耕和铲式浅松等，对土壤结构破坏严重，粘质耕后土层形成较大的块体，特别是春旱严重施水播种时，灌水入渗深度浅，难以为播种提供理想的种床。针对这个问题，我们提出了一种新的表土浅松作业方法，设计了一种新型下插式土壤浅松机具，主要研究内容和结果如下：（1）提出了一种能够满足对土壤表层只松不翻的新型浅松机总体方案和思路，对传动系统及浅松机单体机构的方案进行了设计；（2）根据选定方案的要求和具体浅松作业的要求，对传动系统进行了设计计算，采用基于Pro/E骨架模型的现代设计方法，完成了浅松机单体机构的设计分析和优化；（3）应用Pro/E软件对浅松机的机架、变速机构、传动机构、浅松机单体机构、限位部件进行了数字化建模和实体装配，为动态仿真和有限元分析奠定基础；（4）对浅松机的单体机构做了理论分析，建立了浅松刀具关键参数的数学模型，为浅松机的设计及机构改进提供了理论基础。（5）建立浅松机单体机构虚拟样机模型，在ADAMS中进行了浅松作业的运动、动力学仿真与分析，导出了运动、动力学仿真动画。仿真结果表明：浅松机单体机构浅松刀具能够正常工作，具有急回特性，并且满足浅松作业的要求，配套动力合理。（6）采用ANSYS WORK BENCH对浅松刀具进行了结构静力学有限元分析。浅松刀具最大变形发生在刀刃处，最大位移变形为7.3269mm，浅松刀具的刀柄外侧、刀柄内侧及螺孔处存在应力集中，最大值为311.94MP超出浅松刀具的材料16Mn的屈服强度。（7）根据结构静力学有限元分析，提出了浅松刀具结构改进方案，并再次进行结构静力分析表明：浅松刀具的最大变形为0.8843mm，刀柄外侧、刀柄内侧及螺孔的应力分布集中明显降低，最大应力出现在刀柄的螺孔处为102.21MP，小于16Mn的许用应力；通过模态分析表明：浅松刀具的工作频率不在其固有频率附近，并没有产生共振，满足设计要求。（8）实际试验表明，这种浅松方法若配置“Y”型刀具进行下插式土壤浅松，碎土系数大于90%,土壤容重由1.34g/cm~3变为1.22g/cm~3，降低了8.9%,土壤扰动量14.2%，且上下土层未被搅乱；玉米施水播种时，水入渗深度比普通旋耕法对应值增加了19.3%。不易粘土的“Y”型刀具较理想，应保证刀具松土间隔不大于30mm。研究的创新之处：在下插式土壤浅松方法研究的基础上，设计出新型下插式土壤浅松机，并提出合理减少粘土的浅松刀具。更多还原

【Abstract】 In the way of unreasonable loosening tillage method, the structure of soil was destroyed,saturated water holding capacity and water permeability were decreased, the beneficial livingcreature such as Earthworm were eliminated. So, loosening tillage under ConservationTillage Technology did not induce upper and lower parts of soil excessively inverted. Thekey ubiety of loosening tillage was only loosened not inverted. Up to now, however, variousmethod of surface soil and equipment, such as rotary tillage and shovel surface tillage, eitherdestroyed the structure of soil or Soil Layer formed the larger block after tillage, especiallySpring drought was serious and Water Penetration was shallow during Watering Sowing andIts Application, it was difficult to provide ideal seed bed. To solve those problems, we putforward a new kid of topsoil cultivation method, and has designed New Down EmbededSurface Tillage, the main research content and results are as follows:（1）Proposed the overall concept and the mentality of New Down Embed SurfaceTillage can meet the requirement of only loosened not inverted the soil, and designed theschemes of transmission system and Surface Tillage Monomer;（2）Designed and calculated the structure parameters of transmission system, andDesigned analysis and optimized based on Pro/E Skeleton model for Surface TillageMonomer, according to the requirement of selected plan and topsoil cultivation;（3）Modeled and assembled the Rack, Speed Change Mechanism, TransmissionMechanism, Surface Tillage Monomer, Limited Deep parts by using three-dimensionalmodeling software Pro/E;（4）The key parameters mathematical model of loosening soil tools was established,providing theoretical basis to improve design of Surface Tillage.（5）Established Surface Tillage Monomer device virtual prototyping model byADAMSsimulation software, did the dynamic simulation and analysis of topsoil cultivation, andexported the dynamic simulation animation. The results showed: the loosening soil tools ofSurface Tillage Monomer can work normally with quick-return movement characteristic, andcan meet demand of topsoil cultivation, mating power was reasonable;（6）UsingANSYS WORK BENCH12.0, we analyzed the Y tool for loosening soilwith static analysis of structural finite element, and found that the maximum deformation was7.3269mm on the blade of the Y loosening soil tool, the lateral and medial tool holder and the screw existed the stress concentration, the maximum stress value was311.94MP, whichexceed yield strength of16Mn.（7）According to the results of static analysis of structural finite element, then did thefinite element analysis again. The results showed: the maximum deformation was0.8843mm;the stress concentration reduction obviously in the lateral and medial tool holder and thescrew, the maximum stress value was102.21MP, which was in the range of allowable stressof16Mn. Through the modal analysis showed that working frequency was not near thenational frequency of the structure, and did not produce resonance, meeting the designrequirements.（8）Experiments show that if this new kid of surface tillage method configured the Yloosening soil tools carried out down embed surface tillage experiment; the coefficient ofpulverizing soil was more than90%;soil bulk density decreased by8.9%;the soildisturbance quantity was14.2%,and not disrupted upper and lower soil; The Maize WateringSowing the depth of infiltration compared with rotary tillage increased by19.3%. The Yloosening soil tool was unease clay to make sure the pitch less than30mm.The innovation of the research:The paper had designed new Down Embeded Surface Tillage according to the study ofnew surface soil and surface tillage operation, and put forward a kid of reasonable reducingclay of loosening tools.更多还原