Improved Design And Test Study Of The Belt Type Corn Seed Metering Device

The type hole belt corn seed metering device realizes the high-level seed picking and low-level seeding during the corn sowing process to reduce the bouncing of the seeds after falling into the seed ditch.Aiming at the problems of low qualified rate of seeding and uneven seeding,this paper analyzes the working principle of the seeding process to determine the structural improvement plan and the key factors affecting the seeding performance.Based on the simulation test and bench test,its structural parameters It is determined to improve the seeding qualification rate and seeding uniformity,and the seeding performance is verified through bench tests and field tests.The main research contents and conclusions are as follows:(1)The structural improvement plan of the type hole belt corn seed metering device is determined.Through the analysis of the working process and working principle of the seed metering device,four types of hole structure schemes are proposed for the hole structure:truncated cone,hemisphere,ellipsoid,and cuboid.The hole processing method is 3D printing embedded seed metering belt;If the quality of the tongue cleaning is poor,the soft brush roller cleaning scheme is adopted;for the problem of "flying seeds" in the seeding process,it is proposed to install a seed guard;for the problems of "jamming" and uneven seeding angle in the seeding process,a forced seeding is proposed.device plan.(2)Based on the Recur Dyn and EDEM coupled simulation experiments,determine the structural parameters of seed filling and clearing of the seed metering device.Through the simulation test of the influence of the installation angle of the brush roller,the rotational speed of the brush roller,and the diameter of the seed filling pulley on the qualified rate of seeding,the rate of missed seeding and the replay rate,it is determined that the installation angle of the brush roller is 22°,and the rotational speed of the brush roller is 80 r /min,the diameter of the filling pulley is 170 mm.Through the seed metering test of different shapes of holes,the ellipsoidal hole is preferred;the seeding angle of the seed metering device is analyzed,and the seeding angle of the seed metering device without the seed guard and the forced seed metering device is more than 30°.(3)Design of key components of type hole belt corn seed metering device.Based on the improvement plan and simulation test results,the structure and size of the embedded hole,pulley,seed metering hole,seed box,connection tension plate and seed protection device are designed.Among them,the spacing of the holes is 64 mm,the outer edge matching size is18 mm,the number of teeth of the seeding pulley is 72,the pitch circle diameter is 183.35 mm,the number of teeth of the seeding pulley is 64,the pitch circle diameter is 162.97 mm,and the seeding belt is 1088-8M-45 GB/T13487,the center distance of the pulley is 271.81 mm,and the angle between the forced seeding wire and the center of the bearing hole of the lower connection tension plate and the horizontal line is 30°.(4)Determine the inclination angle and hole structure parameters of the seed metering device based on the bench test.The inclination angle of the seed metering device was determined to be 50° by single factor experiment,and the optimal parameters of the seed metering hole were determined by parameter optimization based on the response surface method: the long semi-axis was 7.384 mm,the short semi-axis was 6.439 mm,and the chamfer was 1.395 mm.The bench verification test shows that the qualified rate of seeding at2,4,6,8,and 10 km/h working speed before the optimization is increased by 4.22%,2.66%,4%,3.66%,and 1.77%.The field test showed that with the increase of working speed,the qualified rate of seeding and the uniformity of seeding showed a downward trend,and the qualified rate of seeding was 92.67%,91.67% and 88.00% at 4,6,8 and 10km/h working speed respectively.%,86.33%,and the coefficient of variation of plant spacing was 4.32%,3.46%,6.28%,and 7.02%.The test results show that the improved seed metering device can meet the requirements of corn precision sowing.