异形型孔式苜蓿精密排种器设计与试验

Design and Experiment of Special-shaped Seed Cell for Alfalfa Precision Seed Metering Device

为提高苜蓿播种环节精细度及种子利用率,设计出一种异形型孔式苜蓿排种器。基于排种器工作原理和苜蓿种子形态,进行充种、清种过程受力分析,设计出异形排种型孔;以型孔前侧导种槽角度、后侧倒角角度、侧边倒角角度、排种盘转速为试验因素,以排种单粒率、漏播率和重播率为评价指标,进行离散元仿真试验,建立试验因素与评价指标间的数学模型。通过响应面法对回归方程进行多目标优化,得到最佳排种参数组合:型孔前侧导种槽角度35°、后侧倒角31°、侧边倒角57°和排种盘转速25r/min时,排种单粒率76.23%,漏播率7.60%,重播率16.17%。选用中苜4号苜蓿品种种子进行播种试验台试验验证,结果表明:设计的异形型孔式苜蓿排种器采用“类条播”农艺进行播种,能够提高排种精细度。

In order to improve the precision of alfalfa sowing and improve the utilization rate of seeds,a special-shaped hole type alfalfa metering device was designed.Based on the working principle of metering device and alfalfa seed morphology,the stress analysis of filling and cleaning process was carried out,and the irregular metering hole was designed.The mathematical model between the experimental factors and the evaluation indexes was established by discrete element simulation experiment with the guide groove angle of the front side of the hole,the chamfer angle of the rear side,the chamfer angle of the side and the rotation speed of the metering plate as the experimental factors,and the single seed rate,the leakage rate and the reseed rate as the evaluation indexes.The multi-objective optimization of the regression equation was carried out by response surface method,and the optimal combination of seeding parameters was obtained the angle of the front side of the hole guide slot was 35°,the back side chamfer was 31°,the side chamfer was 57°,and the rotation speed of the seeding plate was 25 r/min.At this time,the single seed rate of seeding was 76.23%,the missed seeding rate was 7.60%,and the reseeding rate was 16.17%.The seeds of Zhongmu No.4 alfalfa variety were selected for the verification of the sowing test bench.The results showed that the designed special-shaped hole-type alfalfa seed-metering device could improve the precision of seed-metering by seeding with the agronomic of class-strip seeding.