覆草冬种马铃薯收获机稻草分离机构设计与试验

Design and experiment on harvester for winter planting potato of straw coverage

针对残留稻草导致的覆草冬种马铃薯收获机薯土分离效果差、明薯率低等问题,在马铃薯收获机上增设了一套稻草分离机构,通过稻草与分离拨指的运动分析,建立了拨指运动的速度模型,获得拨指拨离稻草速度的最小值为1.99 m/s,通过稻草与拨指在不同运动轨迹处的受力分析,建立了稻草不同分离阶段的状态方程,优化了拨指的运动轨迹。田间试验结果表明:在不清除残草条件下,改制的收获机可实现覆草冬种马铃薯的草、薯、土层次化分离,以及稻草的条铺作业。利用多目标优化设计方法对试验结果进行综合评价表明:当收获机作业速度为0.4 m/s、拨指速度为3 m/s、拨杆数量为6根时,综合作业性能较优,此时明薯率为99.5%,伤薯率为4.2%,薯草分离率为80.4%,均满足冬种马铃薯收获的技术要求。

To increase the soil temperature to ensure that the production of potato,the straw was used to cover the soil when planting potato in the south of China in winter. When the straw-covered winter potato is harvested,there exist several problems such as big digging resistance,easy blocking,difficult separation of straw,and low excavation rate and high injury rate of potato. In order to solve these problems,a harvester for winter planting potato with a straw separation device is developed. The harvester is composed of divided shovel,rod elevating chain,straw separating mechanism and oscillating screen which can finish potato digging,separate potato from soil and straws,orderly placement of potato in one step. This article described the main structure and working principle of the machine. In addition,according to theorem of vector projection,kinetic energy and kinematics,the structure of key parts were designed and the parameters were determined. To evaluate the performance of the harvester,field experiment was carried out,in which the obvious rate of potato,injury rate of potato and reliability were taken as the indexes and the machine forward speed,tilt angle of sieve plate and number of lifting lever were taken as the factors.The multi-objective optimization method was adopted to analyze the experimental data. The results show that when the machine forward speed was 0.4 m?s-1,working finger speed was 3 m?s-1,and the number of working pole was 6,the obvious rate of potato was 99.5%,injury rate of potato was 4.2%,the reliability was 80.4%. The comprehensive performance index was better and meet the using requirements of potato harvester.