小区谷物联合收获机气吹式割台设计与试验

Design and Experiment on Air Blowing Header of Plot Combine Harvester for Grain

为解决现有小区谷物联合收获机割台中有残留、不易清机等问题,设计了一种采用正面气流将禾吹弯再切割的气吹式割台。根据力学原理建立了均匀气流吹禾模型,以小麦顺利进入割台而不掉落为要求,计算得气流支管出口风速为47.35 m/s。以能产生均匀气流为目标,通过理论计算得到气流管道的主要结构参数为:气流总管锥度1∶14.29,气流支管排列间距100 mm。对影响割台残留量和损失率的3个关键工作参数:气流支管出口与割刀的垂直和水平距离、气流支管出口与水平夹角进行了单因素试验和正交试验。单因素试验表明:气流支管出口与割刀的垂直和水平距离在15~27 cm内对割台损失率的影响呈现先降后升的趋势,气流支管与水平夹角对割台损失率和残留量的影响先缓慢减小,后增加较快。正交试验表明:最优组合为气流支管出口与割刀的水平距离21 cm、气流支管出口与割刀的垂直距离21 cm、气流支管出口与水平的夹角10°,此时总损失率为0.88%,割台残留量为1.21 g。气吹式割台残留量少,总损失率低,达到了小区小麦种子收获技术要求。

In order to solve some matters on residual seeds on header and clean the header during harvesting grain seed on the plot by using combine harvester of grain,an air blowing header,by that front airflow bent wheat and then cutter knife cut the wheat stalk,was designed.A blowing cereal model with uniform air flow velocity was established according to mechanics principle.The calculated air flow velocity of branch pipe outlet was more than 47.35 m/s under condition of the cut wheat smoothly entering into the harvester header without dropping.According to the theory of static regain design method of multiple-branch duct system, these calculated main structure parameters of airflow pipe which generated uniform air flow in each branch pipe were taper of air flow main pipe of 1∶ 14.29 and interval distance of air flow branch pipe of 100 mm.Three key parameters,including vertical and horizontal distances between cutting knife and air flow branch pipe outlet,the angle between air flow branch pipe and level,that affected header residual amount and total loss rate,were regarded as experimental factors for conducting single factor and multi-factors orthogonal experiments.The single factor experiments showed that the total loss rate of header with firstly increase and then decrease was made by the vertical and horizontal distances between cutting knife and outlet of air flow branch pipe within a scope of 15 -27 cm.The residues on the header were little affected by horizontal distance between cutting knife and outlet of air flow branch pipe causes.But there was larger effect on the residues on the header for the vertical distance between cutting knife and outlet of air flow branch pipe.The higher the vertical distance was,the more residues were,and even wheat ear was left.The residual and total loss rate of header slowly decreased in 0° - 10°,but rapidly increased in 10° - 20°,which was made by the angle between air flow branch pipe and level.The orthogonal experiments demonstrated that the effect of the angle between air flow branch pipe and level on total loss rate of header and residual amount was the greatest.The vertical distance between cutting knife and outlet of air flow branch pipe was 21 cm,horizontal distance between cutting knife and outlet of air flow branch pipe was 21 cm,and the angle between air flow branch pipe and level of 10° was the optimal orthogonal experiments combination.The total loss rate was 0.88% and the header residue was 1.21 g under the optimal orthogonal experiments combination.The developed air blowing header with small header residual amount and low total loss rate achieved the technical requirements of the plot harvesting wheat seed.