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毛刷带式玉米高速导种装置的设计与试验

Design and experiment for the high-speed maize seed guiding device with brush belt

  • 摘要: 针对气吸式玉米高速播种机导种过程中种子碰撞损伤和投种精度差的问题,该研究设计了一种向控轮旋拨导向-毛刷带转运投种的毛刷带式导种装置。通过对关键结构的设计和理论分析,确定影响导种性能的主要因素和各因素取值范围。利用Adams-EDEM耦合仿真方法进行向控轮导向过程单因素试验,结果表明:向控轮相对排种盘安装角度为15°时,种子满足导向要求且导向轨迹稳定;搭建试验台架,以刷毛长度、带轮直径为试验因素,粒距合格率、重播率、漏播率为试验指标,开展二次旋转正交组合试验,试验结果表明:在作业速度13 km/h条件下、刷毛长度为25 mm,带轮直径为53 mm时,粒距合格率为96.03%,漏播率为1.76%,重播率为3.48%;根据最优参数组合验证不同作业速度下导种装置的性能,结果表明,当作业速度在12~16 km/h时,粒距合格率不低于94.3%,重播率不高于3.92%,漏播率不高于3.19%,破损率不高于0.19%。该研究可为玉米高速播种作业条件下导种装置的设计优化提供参考。

     

    Abstract: Maize is one of the most extensively cultivated grain crops in China. The high-speed precision seeding is required under land intensification, particularly for the optimal timing, entropy-adapted sowing, and yield enhancement. Among them, the air-suction precision seeding can be combined with the constrained seed guide and zero-speed seeding. The disturbing seed filling and multi-stage seed cleaning have been reliable for the high-performance seeding. However, the constrained seed guiding has been confined to the uncontrollable trajectory of seed migration, especially under the strong collision between the seed and the constrained seed guiding device at the high speed. Eventually, there is a sharp increase in the coefficient of variation of the seed spacing, when the seed is thrown. The large initial speed of the seed can be found, when leaving the seed plate in the high-speed corn planter. The collision and bouncing with the inner wall of the seed guide tube can also lead to the decrease in the qualified rate of the seed spacing. In this study, a high-speed seed guiding device with brush belt was designed to transfer the seed into the control wheel that assisted seed-brush synchronous belt. The direction control wheel was utilized with the opening/closing finger shafts to form the seed cavities during guidance. Single grain was sequentially deposited on the brush tubes. The stable transportation and zero-speed delivery were realized after the brush-belt rotation. The performance factors and their operational ranges were identified after structural optimization and theoretical analysis. The dynamic model was constructed for the rotary steering to the control wheel, as well as the transfer and seeding of the brush belt. The influencing factors on the steering trajectory of the control wheel were obtained as the installation angle of the control wheel relative to the seeding plate. The length of the brush and the diameter of the belt wheel were the influencing factors on the stability of the seed holding and seeding of the brush belt. A single-factor test was carried out on the directional control wheel that assisted the seed acceptance using Adams-EDEM coupling platform. The seed was fully met the guidance requirements, when the installation angle of the directional control wheel relative to the seed plate was 15°. The stable guidance trajectory was also achieved after simulation. The secondary rotation orthogonal test was carried out with the brush length and the pulley diameter as the test factors, and the qualified spacing rate, the multiple seeding rate and the missed seeding rate as the test indexes. The test results show that the qualified spacing rate was 96.03%, the missed seeding rate was 1.76%, and the multiple seeding rate was 3.48%, when the operating speed was 13km/h, the brush length was 24.9 mm, and the pulley diameter was 53 mm. The performance of the seed guiding device was verified at different operating speeds, according to the optimal combination of parameters. Once the operating speed was 12-16 km/h, the qualified spacing rate was not less than 94.3%, the multiple seeding rate was not higher than 3.92%, the missed seeding rate was not higher than 3.19%, and the damage rate was not higher than 0.19%. This finding can provide a strong reference to optimize the high-speed seed guide device.

     

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