气吸式胡萝卜起垄播种一体机研制

该研究结合山东等地的胡萝卜垄作种植模式,研制了一种集起垄、开沟、精量播种、覆土、镇压等功能于一体的气力式胡萝卜精量播种机,实现胡萝卜垄上窄行精量播种作业。该机采用负压吸种、正压吹杂完成单粒精量播种,主要由气吸式精量排种器、起垄整形装置、开沟分种装置、覆土器、机架及传动系统组成。根据吸种及投种过程的种子受力及运动分析,得到排种器气室真空度临界值,明确了投种位置及株距均匀性的主要影响因素。设计了双圈型孔排种盘,排种盘内外圈型孔所在圆周半径分别为87.5和95.0 mm,每圈型孔数量为30个。依据清种要求及作业空间,设计锯齿刮板式及偏心式刮种器,实现型孔两侧刮种;根据种植农艺要求,确定FL-2.5型风机,实现不同播种风量要求;采用3个双翼铧式犁起垄,并通过整形装置对垄形进行修整,一次完成2个梯形垄;遵循单体双窄行、浅开沟及少覆土要求,确定了开沟分种结构及覆土板参数。依据投种过程分析,采用低位投种方式,最低限度布置排种器,开沟分种装置总体高度在100mm左右。以排种盘型孔直径、排种盘转速和气室负压为试验因素,以粒距合格率、漏播率和重播率为试验评价指标,进行三因素五水平的二次回归正交旋转组合试验,获得排种器最佳参数组合为型孔直径1.6mm,排种盘转速18 r/min,气室负压4.4k Pa。田间试验结果表明,该机播种粒距合格率大于94%、漏播率小于5%、重播率小于4%,满足相关国家标准及胡萝卜种植农艺要求,可为胡萝卜精量播种机具的设计提供参考。

Development of air-suction ridging and seeding machine for carrot

Combineding with the ridge planting mode of carrot in Shandong and other places, this research developed a air-suction precision carrot seeder which integrated the functions of ridging, ditching, precision sowing, covering soil and pressing was developed. The machine was mainly composed of air-suction precision metering device, ridging and shaping device, ditching and seed dividing device, soil covering device, frame and transmission system. According to the analysis of the force and movement of seeds in the process of seed suction and seeding, the critical value of vacuum degree in the air chamber of seed metering device was obtained, and the main influencing factors of seeding position and plant spacing uniformity were determined. A seed-metering plate with double-ring type hole was designed, the radius of the inner and outer circle holes of the seed-metering plate was 87.5 and 95 mm respectively, and the number of holes in each circle was 30. According to the requirements of seed cleaning and working space, the upper scraper removed the excess seeds adsorbed on the upper side of the inner and outer ring type holes, the zigzag structure was adopted. The lower scraper removed the excess seeds adsorbed on the lower side of the inner and outer ring type holes, and the eccentric structure was used. According to planting agronomic requirements, the FL-2.5 fan was determined to meet the requirements of different sowing air volume. Three double-wing ridging plows were used to ridge, and the ridge shape was trimmed by a shaping device to complete 2 trapezoidal ridges at one time. According to the requirements of double narrow row, shallow ditching and less covering soil, the structure of ditching and the parameters of overburden were determined. According to the analysis of the seed feeding process, the low-level seed feeding mode was adopted, and the seed metering the overall height of the ditching and seed separation device was about 100 mm. Taking the type hole diameter of the seed-metering plate, the rotating speed of seed-metering plate and the negative pressure of the air chamber as the test factors, and taking the eligible rae of seed spacing, the missing rate and the multiple rate as the test evaluation indexes, three-factor and five-level orthogonal experiment was carried out. The best working parameter combination for seed-metering device was abtained: the type hole diameter was 1.6 mm, the rotating speed of seed-metering plate was 18 r/min, and the negative pressure of the air chamber was 4.4 kPa. The field sowing experiments were carried out at working speeds of 3, 4 and 5 km/h respectively. The experiment results showed that with the increase of working speed, the eligible rate changed little, the multiple rate decreased, and the missing rate increased, but the overall scope of change was not large, the eligible rate was more than 94%, the missing rate was less than 5%, and the multiple rate was less than 4%, the working performance of the machine met the national standard and the requirements of carrot planting agronomy. The study can provide reference for the design of precision seeder for small seed vegetables such as carrot.