| Soybean is an important grain,oil and protein raw material in Anhui Province.It is also an excellent crop combined with planting and breeding land.Its mechanized planting methods include rotation,intercropping and undercrop sowing.Soybean precision seeding technology has many advantages such as saving time and labor,saving cost and increasing efficiency,and suitable for mechanized harvesting.As the core working component of soybean precision seeding technology,the seed meter plays a key role in adapting to different planting methods and seeding quality.This thesis aims at the problem that the traditional soybean single-row pneumatic precision metering device multi-row parallel seeding process is complicated in structure and the single seed seeding is difficult to ensure the seedling rate due to the large amount of the previous crop of straw.It is based on the combined technology of slot-tooth scrambling and pneumatic seeding.Developed a soybean double-disc perturbation pneumatic precision hole seeding and metering device.The main conclusions are as follows:(1)Based on the principle of perturbation adsorption combination,a double-disc perturbation pneumatic precision hole seeding and metering device is designed,and the working principle and key components of the seed metering device are designed and analyzed,and the seeding,carrying and seeding stages are driven.Kinematics and kinematics analysis determine the conditions that the seeds must meet for stable adsorption during the stage of sucking and carrying seeds,and the working parameters and structural parameters of the seed metering device are determined.(2)Based on the principle of perturbation adsorption combination,a double-disc perturbation pneumatic precision hole seeding and metering device is designed,and the working principle and key components of the seed metering device are designed and analyzed,and the seeding,carrying and seeding stages are driven.Kinematics and kinematics analysis determine the conditions that the seeds must meet for stable adsorption during the stage of sucking and carrying seeds,and the working parameters and structural parameters of the seed metering device are determined.(3)Based on the EDEM software to simulate different types of seed discs,the average distance between the seeds and the seed disc is used as the perturbation intensity evaluation index,and the disturbance intensity of discs B,C and D is obtained.The average kinetic energy of the population is used as the evaluation index,and the rotation speed of the seed disc is obtained.As the speed increases,the average value of the kinetic energy of the various disks increases,and the C disk and the D disk are both larger at different speeds.Based on the Fluent software to simulate different types of holes,it is obtained that there is no obvious turbulence at the air inlet of the outlet cone-shaped cylindrical hole;taking the negative pressure of the air inlet as the evaluation index,the outlet cone-shaped cylindrical hole is obtained under the same negative pressure at the outlet.The maximum negative pressure at the inlet indicates that the cone-shaped cylindrical hole at the outlet is easier to adsorb seeds.(4)The seed filling performance test shows that when the speed range of the seed disc is 7-28r/min and the working negative pressure is not greater than 3.0k Pa,the filling qualification rate of the four different structure types of seed discs is significantly different,and the linear groove tooth disc is filled.The pass rate can reach 95.78%,which is the best among the four.The seed metering performance test is carried out with the combination technology of the linear grooved disk and the flexible parallel seed cleaning device.The results show that at the same speed,the missed seeding rate is negatively correlated with the working negative pressure;under the same negative pressure,the missed seeding rate It is positively correlated with the rotation speed;when the negative pressure is not less than3.0k Pa,and the seed disk rotation speed is within the range of 7-28r/min,the qualified rate of the number of holes can reach over 95%. |
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