Abstract:A air-suction double-row staggered precision seed metering device was designed to address the problems of short filling time and poor airflow stability caused in the high-speed operation of the traditional air-suction seeder's single row seed tray, which made it difficult to achieve high-speed and precise seeding in the soybean corn compound dense planting mode. The structure and working principle of the seeder were explained, theoretical analysis of the seeding process and key components, construction of seed mechanics models for filling and seeding stages, determination of key structural parameters such as the arrangement of inner and outer ring holes in the seeding disc, seeding wheel, and air chamber, and analysis of negative pressure distribution and airflow characteristics inside single and double air passages were done. Based on the DEM-CFD coupling method, the seeding process of the seeder was simulated and analyzed with operating speed, air chamber structure and negative pressure as experimental factors, and filling qualification rate, refilling rate and leakage rate as evaluation indicators, the optimal chamber structure was selected. A comparative test was conducted on the seeding performance of different air-suction seeders through bench tests. The test results showed that the air-suction double-row staggered dense planting precision seeder had a seeding qualification index greater than 88.7% under high-speed dense seeding conditions with operating speeds of 5~10km/h. Moreover, compared with the commonly used single ring air-suction seeder at operating speed of 10km/h, the qualification index was increased by 5.5 percentage points and the missed seeding indexwas decreased by 5.6 percentage points. The field test results showed that under the working condition of 5km/h, the qualified sowing index was 95.7%, the replanting index was 1.6%, and the missed sowing index was 2.8%. The proposed air-suction double-row staggered corn dense planting precision seeder had good seeding performance in high-speed operation and could meet the requirements of high-speed precision seeding of soybeans and maize.
