Authors

Abstract

In order to reduce the problems of high grain breakage rate and uncleaned material rate in the threshing and separating device of longitudinal axial flow corn, a threshing device of "front flexible nail tooth + rear pressure spring elastic short grain rod" was designed and the threshing elements were arranged spirally on the conical threshing drum. Discrete element method and field test were used to verify the feasibility of threshing drum design, and EDEM simulation software was used to obtain the appropriate guide plate Angle parameter range. Single factor test was carried out on each experimental factor under high and low water content conditions, and four factors suitable working range was obtained.On this basis, four factors and three levels orthogonal test were carried out on grain breakage rate and undepurated rate, rotational speed of roller, feeding rate, cylinder-concave clearance and deflector angle as experimental factors. Range and variance analysis were used to analyze the rotational speed of roller, feeding rate, cylinder-concave clearance and deflector angle. The results showed that:Under the conditions of low water content, the threshing effect is the best under the conditions of feeding rate of 8kg/s,rotational speed of roller of 450 r/min, cylinder-concave clearance of 45 mm, and deflector angle of 70°.Under the conditions of high water content,the best threshing effect was achieved under the conditions of feeding rate of 7kg/s, rotational speed of roller of 450 r/min, cylinder-concave clearance of 40 mm and deflector angle of 75°. Compared with the conventional threshing separation device, the grain breakage rate of low moisture content decreased by 39.4% and the uncleaned material rate decreased by 63.9%.The grain breakage rate of high moisture content was reduced by 45.5%, and the uncleaned material rate was reduced by 66.7%, which was better than the conventional longitudinal axial flow threshing separation device. The research results can provide reference for the design and optimization of longitudinal axial flow corn harvester. 

Abstract in Chinese

为了减少纵轴流玉米脱粒分离装置的破碎率高、未脱净率高的问题，设计了一种“前柔性钉齿+后压簧弹性短纹杆”的脱粒装置和脱粒元件在锥形脱粒滚筒上的排列方式。采用离散元法和现场试验对脱粒滚筒设计的可行性进行了验证，采用EDEM仿真软件得到了合适的导板角参数范围。在高、低含水率条件下对各试验因素进行单因素试验，得到四因素合适工作范围，在此基础上，以滚筒转速、喂入量、脱粒间隙和导流板角度为试验因素，对籽粒破碎率和未脱净率进行四因素三水平正交试验。采用极差与方差分析方法对滚筒转速、喂入量、脱粒间隙和导流板角度进行分析，结果表明：在低含水率时，参数组合为喂入量 8kg/s、滚筒转速 450 r/min、脱粒间隙 45 mm、导流板角度 70°的情况下脱粒效果最好，在高含水率时，参数组合为喂入量 7kg/s、滚筒转速 450 r/min、脱粒间隙 40 mm、导流板角度 75°的情况下脱粒效果最好，与常规的脱粒分离装置相比，低含水率籽粒破碎率降低了 39.4%，未脱净率降低了 63.9%，高含水率籽粒破碎率降低了 45.5%，未脱净率降低了 66.7%，优于常规的纵轴流脱粒分离装置。研究结果可为纵向轴流玉米收获机的设计与优化提供参考。