Design And Performance Test Of A Dustpan-shaped Combined Hole Wheel For Corn And Soybean Universal Hole Seeder

Corn and soybeans are important grain crops in Anhui Province.They are widely planted in the region,with a high degree of mechanization in large-field planting.However,there is a lack of reliable lightweight and simple technology for simultaneous sowing of corn and soybeans in small-field plots,as well as dedicated supporting devices.To address the limitations of mechanical hole-type seeders,such as single seeding targets,high breakage rates of traditional protective seeds,and inconvenient unloading,a dustpan-like hole-type corn-soybean seeder with a U-shaped comb-like protective device was designed using a combination of variable-capacity seed filling and elastic protective coating technologies.By employing methods that combine dynamics and kinematics theories,discrete element numerical simulation,finite element simulation analysis,and bench performance tests,a mechanical model for the orderly movement of seeds was established.The structural parameters of the key components of the seeder were analyzed and determined,and a simulation model for the interaction between seeds and key components was constructed.Performance tests for simultaneous corn and soybean hole sowing were conducted.The main research work and conclusions are as follows:(1)Determined the parameters of corn and soybean seed materials.The physical characteristics of Zhengdan 958 corn seeds and Wando 37 soybean seeds,which are representative planting varieties in Anhui Province,were measured.Seed moisture content,thousand-grain weight,packing density,and volumetric weight were determined.The friction characteristics,including the elastic collision restitution coefficient,static friction angle,and natural repose angle between seeds and materials,were obtained by experiments.The three-axis size distribution of the seeds was statistically analyzed,and a particle model for the seeds was established,providing basic data for the design,theoretical analysis,and simulation of key components of the seeder.(2)Designed the key components of the seeder and analyzed the sowing process.Based on the measured three-axis size distribution of seeds and the requirements of agricultural planting,the composition and working principles of the seeder were mainly described.A corn-soybean seeder with a combined dustpan-shaped hole and an optimized seed insertion opening was designed.A U-shaped comb-like elastic protective plate was proposed to improve the structure of the unloading plate.The interaction between seeds and key components during the sowing process was analyzed based on dynamics and kinematics theories.The key structural parameters of the seeder,factors affecting the cleaning process,and speed limits were determined.(3)Conducted the simulation analysis of the sowing and protective performance of the seeder.Discrete element seed parameter calibration and numerical simulations were performed to clarify the performance differences of different structural hole types.The differences in seed filling and sowing time between different structural hole types were compared,and the influence of different seed insertion openings on sowing performance was explored.Finite element simulation methods were used to determine the numerical changes in material internal stress and seed pressure during the protective process of different structural protective plates.(4)Bench performance test of the seeder.Through comparative tests on the bench with different hole types and opening sizes,the results showed that the optimal opening sizes for corn and soybean sowing were 14 mm and 12 mm,respectively.At these opening sizes,the qualified sowing rates of corn and soybeans with the combined dustpan-shaped hole were97.2% and 98.1%,respectively.Compared to the waist-groove-shaped and inverted coneshaped holes,the sowing leakage rates of corn and soybeans were reduced by 1.8%,2.4%,and 2.5%,4.3%,respectively.The combined dustpan-shaped hole exhibited superior seed filling performance.Within the design parameters,changes in sowing operating parameters had a minor impact on the performance of the seeder.The U-shaped comb-like protective plate resulted in corn and soybean damage rates not exceeding 0.33% and 0.1%,respectively,within the designed rotation speed.Compared to the flat protective plate,the highest damage rates of corn and soybeans decreased by 6.57% and 0.73%,respectively,with reductions of6.9% and 0.83%.Through the seeder bench test for forming holes,the minimum qualified hole spacing rate for corn was 98.8% at the test speed,and the minimum qualified hole spacing rate for soybeans was 99.2%.The results of the bench performance test indicate that the overall performance of the seeder meets the requirements of agricultural planting.