Design And Experiment Of The Precision Metering Device With Staggered Convex Teeth And Wide Seedling Belt For Wheat

The combination of wide seedling belt sowing technology and precision sowing technology can enable wheat roots to absorb nutrients more fully,thereby significantly improving wheat productivity.However,the current wide seedling belt planting technology combined with sowing machinery is difficult to achieve precise sowing,and usually mechanical external groove wheel seeders are used for sowing.This sowing method can lead to problems such as uneven distribution of seeds within the seedling belt,pulsation,and unstable sowing quantity,causing wheat seeds to randomly fall into the seed ditch,resulting in a high rate of damage.Therefore,this study proposes a wide seedling belt wheat precision seeder,which is of great significance in solving problems such as seeding uniformity and seeding stability.The main research content is as follows:(1)Agronomic requirements for wide seedling belts and measurement and modeling of wheat seed material parametersThrough research on the high yield cultivation technology of precision sowing with wide seedling belt for wheat,it is understood that the sowing rate for wide seedling belt for wheat is generally between 8-12 kilograms per acre,and adjustments are made based on local soil quality,seed quality,planting density,and other factors.The measurement of the material characteristics of wheat seeds laid the foundation for the design of key components of the wheat seeding system,and a three-dimensional model of wheat seeds was drawn to prepare for future EDEM numerical simulation experiments.(2)Design of a Cross Convex Gear Wide Seedling Belt Wheat Seeding DeviceDesign key structures and parameters,then conduct 3D modeling for simulation and prototype trial production,obtain solid models through 3D printing,and verify their feasibility through bench and field experiments.According to agronomic requirements,national standards,and industry standards,its structure was analyzed and nine different combinations of convex gear parameters were designed.(3)Analysis of the Seed Arrangement Performance of the Cross Convex Toothed Wide Seedling Belt Wheat Seed Arrangement DeviceBased on the discrete element method,analyze the motion characteristics of seeds in the seeder and perform force analysis.Design an orthogonal rotation center combination experiment to analyze the uniformity variation coefficient and displacement uniformity variation coefficient of nine different parameter combinations of convex gears under different working conditions such as agronomic requirements of 8-12 kg and speed of 4-6km/h.Through response surface analysis,the optimal solution parameter combination of convex gears is obtained as convex tooth height of 5mm and convex tooth angle of 75°.(4)Bench and Field TrialsConduct bench and field experiments to verify its feasibility and accuracy under different agronomic requirements.The bench test results showed that the maximum uniformity variation coefficient of the staggered convex tooth seeder under different agronomic requirements is 3.94% lower than that of the outer groove wheel seeder;The maximum displacement consistency coefficient of variation is 1.17% lower.The field experiment showed that the maximum uniformity coefficient of variation of the staggered convex tooth seed metering device under different agronomic requirements was 3.02%lower than that of the outer groove wheel seed metering device;The maximum displacement consistency coefficient of variation is 0.98% lower.The uniformity variation coefficient of grain drill sowing machine seeding required by the national standard shall not exceed 40%.After comparison,the two types of variation coefficients of the staggered convex tooth seeder are better than the outer groove wheel type,demonstrating its advantages in seeding uniformity,stability,and other aspects,meeting the agronomic requirements of wheat wide seedling belt precision sowing.