Coaxial Drive–Vacuum System for Maize Precision Seeding

In air-suction maize precision seed metering, the power transmission and vacuum air supply are typically routed through separate, non-coaxial paths. This conventional layout leaves transmission components exposed to debris clogging, subjects the seed-metering disc to eccentric torque, and causes non-uniform suction pressure distribution, ultimately degrading seeding consistency. To address these issues, this study proposes a coaxial integrated design in which a servo motor offset from the seed-metering axis drives a hollow rotary support, and the drive output shares the same axis with the central air passage. Bench tests showed that motor-end feedback speed entered the final target-speed ±5% band within 8.0–36.6 ms, with maximum overshoot of 0.15–5.76%. Seed-disc pre-filling reduced the mean unseeded distance at start-up from 83.1 to 10.4 cm (87.5%, p < 0.001). Field verification at target spacings of 15 and 20 cm and measured speeds of 3.0–12.0 km/h produced quality-of-feed indices of 91.74–97.50%. The results demonstrate the functional implementation and operational feasibility of the proposed electric-drive system under the tested conditions.