Abstract:Aiming at the problem that grains bounce badly in the seed guide tube when sowing, resulting in poor hole formation after landing, a spoon chain seed guide device for grain hole seeder was designed. Its working principle was to improve the hole formation after landing by restraining the seed transport trajectory, the key components were designed, the motion analyses were carried out on the seed storage and seed casting process, and the important factors affecting the performance of the seed guide were determined. In order to obtain the best combination of parameters, three types of spoons, namely, round spoon, square spoon and square flat spoon, and three types of materials, namely, ABS, rubber and acrylic, were used as factors in the one-way test, and the test results showed that the square flat spoon and the rubber material were the most effective. On this basis, the angle of incorporation of seeds, height of incorporation seed and sprocket speed were taken as the incorporation of seed test factors, and the seeding qualification rate was taken as the evaluation index;the seeding height, seeding angle and sprocket speed were taken as the seeding test factors, and the qualification rate of hole diameter, qualification rate of the number of holes and the coefficient of variation of hole spacing were taken as the seeding evaluation indexes, and the three-factor, five-level quadratic rotational combination test was carried out for the seeding and the seeding process through the EDEM discrete element simulation software, respectively.The optimal parameter combinations for the seed-retention process were seed-retention angle of 45.95°, seed-retention height of 74.05mm, and sprocket rotational speed of 1.76r/s;and the optimal parameter combinations for the seed-introduction process were seed-introduction angle of 53.51°, seed-introduction height of 25.96mm, and sprocket rotational speed of 1.98r/s. In order to further validate the performance of seed-guiding device, bench-top validation test and comparative test were carried out under the optimal parameter combinations. In the test, the seed qualification rate was 95.53%, the hole diameter qualification rate was 93.29%, the hole number qualification rate was 94.73%, and the coefficient of variation of hole spacing was 7.46%, and the results of the bench validation test were basically the same as those of the simulation test, with the relative differences being less than 5%;and the results of the comparative test showed that the sowing effect of the installation of the spoon chain seed-guiding device was significantly better than that of the installation of the seed-guiding tube, and the hole diameter qualification rate. The qualified rate of hole diameter, qualified rate of hole number and coefficient of variation of hole spacing can be improved by 2.75, 3.43 and 3.25 percentage points.
