大豆垄上双行免耕播种机锯齿式开沟器设计与试验

在玉米-大豆轮作免耕种植模式下,针对玉米根土结合体较大且垄向分布不均匀,阻碍大豆垄上双行播种开沟器垄向运动,导致播种深度均匀性和行距一致性较差等问题,设计了一种锯齿式大豆垄上双行播种开沟器。在阐述锯齿式大豆垄上双行播种开沟器结构和工作原理的基础上,对前刀曲线进行了设计,推导出前刀曲线方程;分析了侧刃切割根系力学模型,确定侧刃为锯齿形;对玉米根土结合体进行农艺学测量,确定了锯齿形侧刃的关键参数;根据大豆播种的农艺要求,明确了开沟器主体内导种管以交错形式布置,同时确定了锯齿式开沟器的入土隙角为5°。离散元仿真试验结果表明:锯齿式开沟器能有效切断玉米根系且有较优的工作稳定性,进而验证了设计的合理性。在机组前进速度7 km/h、开沟深度50 mm条件下,以根系切断率为主要指标进行田间性能试验,结果表明:锯齿形侧刃有较强的锯切能力,平均根系切断率达97.25%。与双圆盘开沟器进行田间对比试验,结果表明:锯齿式开沟器比双圆盘开沟器开沟深度变异系数降低43.33%、种子横向距离变异系数降低60.81%。仿真试验和田间试验均表明锯齿式开沟器满足免耕大豆垄上双行播种农艺要求。

Design and Experiment of Zigzag Opener for Double-row No-tillage Seeding on Soybean Ridge

Under the corn-soybean rotation no-tillage planting mode, the corn root-soil combination is large and the ridge distribution is uneven, which hinders the ridge movement of the double-row sowing opener on the soybean ridge, resulting in the uniformity of the seeding depth and the consistency of the row spacing. For poor problems, a double-row sowing opener on a sawtooth soybean ridge was designed. Based on the description of the structure and working principle of the double-row sowing opener on the zigzag soybean ridge, the rake curve was designed, and the rake curve equation was deduced;the mechanical model of the side cutting root system was analyzed, and the side cutting was determined to be sawtooth. The agronomic measurement of the corn root-soil combination determined the key parameters of the sawtooth side edge;according to the agronomic requirements of soybean seeding, it was clear that the seed guide tube in the main body of the opener was arranged in a staggered manner, and the sawtooth opening was determined. The gap angle of the ditch device was 5°. The results of the discrete element simulation verification test showed that the sawtooth opener can effectively cut the corn root system and had better working stability, which verified the rationality of the design idea. Under the conditions of a forward speed of 7km/h and a trenching depth of 50mm, the field performance test was conducted with the root cutting rate as the main indicator. The results showed that the serrated side edge had a strong sawing ability, and the average root cutting rate was 97.25%. Field comparison experiments with double-disc openers showed that compared with double-disc openers, the coefficient of variation of trenching depth was reduced by 43.33%, and the coefficient of variation of transverse seed spacing was reduced by 60.81%. Both the simulation test and the field test showed that the sawtooth opener met the agronomic requirements of double-row sowing on no-till soybean ridges.