丘陵山区小型马铃薯收获机设计与试验

Design and experiment of small-sized potato harvester suitable for hilly and mountainous areas

针对中国西南丘陵山区马铃薯收获作业中存在的引进机型适用性低、明薯率低、伤薯率高、破皮较严重、机械化收获程度低的问题,设计一种适用于丘陵山区的小型马铃薯收获机,整机主要由三点悬挂装置、挖掘装置、激振式分离筛、多级振动调整装置、挖掘调整装置、变速箱、传动装置等组成。结合具体作业要求,对挖掘装置和升运分离装置进行参数确定和选型设计。挖掘铲为设有圆弧过渡曲面的二阶铲,增强了碎土剪切性能,提高了顺土能力。建立挖掘过程的挖掘装置阻力模型和运动学模型,并对挖掘装置进行有限元分析,得出挖掘装置的最大应变为5.05×10-8 m·m-1,最大应力为9327.7 Pa,最大变形为2.98×10-4 mm。建立马铃薯升运过程的运动学模型,对薯土混合物的运动形态进行分析,根据所计算的相关参数设计了二次正交旋转组合试验,分别对各试验指标进行响应曲面分析。发现影响明薯率的主要因素为作业速度和分离筛倾角,影响伤薯率的主要因素为作业速度和分离筛倾角,影响破皮率的最主要因素为入土角和分离筛倾角。田间试验结果表明:当作业速度为1.05 m·s-1,入土角为17°,分离筛倾角为15°时,试验条件下的明薯率为96.7%,伤薯率为1.3%,破皮率为1.5%,上述指标优于国家标准,符合马铃薯收获作业要求。

In view of the problems of low applicability,low exposure rate,high damaged rate,serious skin breakage,and low mechanical harvest level in imported potato harvester model operations,a small-sized potato harvester suitable for hilly and mountainous areas was designed,which mainly included three-point suspension device,excavating device,exciting separating screen,multi-stage vibration adjusting device,excavating adjusting device,gearbox,transmission device,etc.The parameter determination and type selection design of excavating device and lifting and separating device were carried out according to the specific operation requirements.The excavating shovel was a second-order shovel with an arc transition surface,which enhanced the performance of soil crushing and shearing,and improved soil guiding ability.The resistance model and kinematics model of the excavating device during work were established,and the finite element analysis was performed on the excavating device.Analysis showed that the maximum strain of the excavating shovel was 5.05×10-8 m·m-1,the maximum stress was 9327.7 Pa,and the maximum deformation was 2.98×10-4 mm.The kinematic model of the potato lifting process was established to analyze the movement forms of the potato-soil mixture,and the quadratic orthogonal rotation combination test was designed with calculated parameter.Based on the response surface analysis of each test index,the main factors affecting exposure rate were operating speed and slope angle of screen surface;the main factors affecting damaged rate were operating speed and slope angle of screen surface;the main factors affecting the breakage rate were the penetration angle and the slope angle of screen surface.The field test showed that,when the operating speed was 1.05 mm·s-1,the penetration angle was 17°,and the slope angle of screen surface was 15°,the exposture rate was 96.7%,the damaged rate was 1.3%,and the skin breakage rate was 1.5%,which were better than the national standard,and met potato harvesting operation requirements.