勺式精量玉米排种器取种凹勺改进设计与试验

Improve design and experiment on spoon of spoon precision seed metering device

为满足精密播种作业,以勺式精量玉米排种器为研究载体,建立充种过程动力学模型,分析工作转速对种勺持种性能影响,设计一种组合曲面式取种凹勺。以工作转速、种勺长度、种勺高度和种勺包角为试验因素,排种合格指数和变异系数为试验指标,进行EDEM正交虚拟排种试验。结果表明,影响排种器排种性能因素依次为:工作转速、种勺包角、种勺长度、种勺高度。排种器工作转速20 r·min-1、种勺长度14 mm、种勺高度13.5 mm、种勺包角19°时,排种质量最优,合格指数为92.35%,变异系数为11.23%。通过台架验证性试验,结果显示,台架试验结果与虚拟仿真基本一致,排种器作业质量随工作转速增加而降低,合格指数最大误差为4.9%。

In order to meet the requirements of precision planting, with spoon precision seed metering device as the study carrier, the dynamical filling-seed model of spoon was established, and then analyzing the influence of rotational speed to improve seeding performance. The optimal design of structural parameters of spoon was conducted based on the analysis of the working principle. The discrete element method （DEM） model of spoon precision seed metering was established. The orthogonal seeding performance experiments of numerical simulation were carried out with the rotational speed, the length of spoon, the width of spoon and the wrap angle of spoon as the experiment factors, the seeding qualified index and the seeding coefficient as the experimental indexes. The simulation results showed that the primary and secondary order of the effects of every factor was the rotational speed, the wrap angle of spoon, the length of spoon and the width of spoon. The rotational speed was 20 r. min1, the length of spoon was 14 mm, the width of spoon is 13.5 mm and the wrap angle of spoon was 19°, and the seeding qualified index was 92.35%, the seeding coefficient was 11.23%. In the same condition, the bench test was done. The test results showed that with the increase of rotational speed, the seeding quantity had a decreasing trend, and the maximum error of the qualified index was 4.9%, this paper could provide the guidance and direction for the research of mechanical precision seed-metering device and its key components.