新疆膜下大豆收获机脱粒装置设计与脱出物分布规律研究

Design of Threshing Device for Xinjiang Under-mulch Soybean Harvester and Distribution of Threshed Materials

摘要:

针对新疆地区膜下大豆在收获期茎叶青绿、草谷比大、含水率高所引起的脱出物分布不均与脱粒质量不稳定的问题，通过系统测定大豆植株形貌特征、各组分含水率及物料与脱粒元件间的摩擦特性，明确了相关物料参数，并以此为依据设计了脱粒装置。以滚筒转速、喂入量和脱粒间隙为试验因素，开展了单因素脱粒试验，系统分析脱出物分布规律。结果表明：大豆茎秆平均直径为 9.59mm, 籽粒三轴尺寸近似正态分布。籽粒侧放受力阈值不超过 73.7N, 茎秆与钢板间的摩擦因数最大为 0.58, 茎秆含水率最高，达 34.0%。脱出物沿滚筒轴向呈现先迅速升高后缓慢下降的趋势，径向分布表现为两侧高、中间低的特征。在滚筒转速为 500r/min 时，轴向与径向变异系数分别降至 50.05% 和 50.82%, 分布均匀性最优。喂人量增大导致径向变异系数显著上升，分布均匀性下降。脱粒间隙为 25mm 时径向分布最均匀，变异系数为 59.73%。研究结果可为适应膜下大豆物料特性的脱粒装置结构优化与作业参数设置提供参考。

Abstract:

Aiming to address the uneven distribution of threshed material and unstable threshing quality caused by the green stems and leaves, high straw-to-grain ratio, and high moisture content of soybeans planted under plastic film in Xinjiang during the harvest period, key material parameters were clarified through systematic measurement of the plant's morphological characteristics, moisture content of its components, and frictional properties between the material and threshing components. Based on these parameters, a vertical axial-flow threshing device was designed. Single-factor threshing experiments were conducted with drum speed, feed rate, and threshing clearance as experimental factors to systematically analyze the distribution pattern of the threshed material. The results indicated that the average stem diameter of the soybeans was approximately 9.59 mm, and the tri-axial dimensions of the seeds approximately followed a normal distribution. The lateral compressive foree threshold for seeds did not exceed 73. 7 N. The friction coefficient between stems and steel plate was the highest at 0. 58, and the stem moisture content was the highest at 34. 0%. The mass of threshed material along the drum axis showed a trend of rapid increase followed by a slow decrease, while the radial distribution was characterized by higher mass at both sides and lover in the center. At a drum speed of 500 r/min, the axial and radial coefficients of variation were decreased to 50. 05% and 50. 82%, respectively, indicating optimal distribution uniformity. An increase in feed rate led to a significant rise in the radial coefficient of variation and a decrease in uniformity. The radial distribution was most uniform at a threshing clearance of 25 mm, with a coefficient of variation of 59.73%. The findings can provide a reference for the structural optimization of threshing devices and the setting of operational parameters to adapt to the material characteristics of soybeans under plastic film mulch.