玉米精量播种复合作业机具设计及试验

Design and experiment of compound operation machine for precision sowing of maize

针对现有玉米播种机播种精度以及播种合格指数较低的问题,设计一种玉米精量播种复合作业机具。阐述播种复合作业机具的工作原理以及主要技术参数,一次进地可同时完成苗带旋耕、施肥、精量播种、覆土和镇压等工作。选用苗带旋耕,并对旋耕机构作业运动状态进行理论分析,确定旋耕刀周向排列,来达到保护性耕作和提高播种精度的要求。确定平行四连杆仿形机构的总体结构,并对其进行受力和尺寸参数分析,通过计算得到仿形机构的杆长,使播种单体有足够的仿形量,保证播深一致性。选用气吸式排种器,确定气吸式排种器结构,计算得出排种器最高转速,可达到精量播种的目的。在黄淮海地区进行田间试验,结果表明:当播种机作业速度为4 km/h,苗带旋耕机构转速为280 r/min时,机具通过性良好,苗带宽度合格率为93.5%,播深合格率为93.1%,粒距合格率为93.5%,重播率为5.9%,漏播率为3.3%,合格粒距变异系数为15.64%。各项性能指标满足农艺要求。

Aiming at the problem of low sowing accuracy and low sowing qualification index of existing corn seeders,a kind of corn precision sowing compound operation machine is designed.The working principle and main technical parameters of the sowing composite operation machine are expounded,and the work of rotary tillage,fertilization,precision sowing,mulching and suppression of seedlings can be completed at the same time in one entry.Seedling belt rotary tillage was selected,and the operation motion state of rotary tillage mechanism was analyzed theoretically,and the circumferential arrangement of rotary tillage knives was determined to meet the requirements of protective tillage and improving sowing accuracy.The overall structure of the parallelogram profile mechanism was determined,and the force and size parameters were analyzed,and the rod length of the profiling mechanism was obtained through calculation,to make the sowing cell have enough profiling to ensure the consistency of the sowing depth.The air⁃suction seeder was selected,the structure of the air⁃suction seeder was determined,and the maximum speed of the seeder was calculated,which could achieve the purpose of precise seeding.The field test in Huang⁃Huai⁃Hai area showed that when the operating speed of the seeder was 4 km/h and the speed of the seedling belt rotary tillage mechanism was 280 r/min,the passability of the machine was good,the pass rate of seedling belt width was 93.5%,the qualification rate of sowing depth was 93.1%,the pass rate of grain size was 93.5%,the replay rate was 5.9%,the missed broadcast rate was 3.3%,and the coefficient of variation of qualified grain size was 15.64%.The performance indicators meet the agronomic requirements.