Design And Research Of Buckwheat Internal Seeding Centrifugal Seed Metering Device

Buckwheat is a well-known small grain which is known as the "King of Grains" in China.It is rich in various trace elements and vitamins,and has high edible value and medical protection.The future development prospects are very promising.China is a big country producing buckwheat.The annual planting area is about 1.3 million hm²,and the total output is 750,000 tons.The planting area and output rank second in the world.Judging from the national buckwheat production situation,the main problems are poor production conditions,low farmers’ income,extensive farming,irregular planting techniques,and manual sowing or animal-powered plough sowing,with a very low degree of mechanization.The scattered planting pattern and extensive production cause high product impurity and loss rates,and product quality is uneven.At present,there is still no substantial breakthrough and progress in the application of buckwheat precision seeding and harvesting machinery.Therefore,the special development of buckwheat seeders has provided advanced cultivation techniques and special machinery for buckwheat production.The development of the buckwheat industry is very important.The buckwheat internal seeding centrifugal seed meter designed in this paper uses centrifugal force to complete the seed filling,seed protection and seeding process.By using centrifugal force,high-speed seed seeding can be achieved to improve business efficiency.The main content and research conclusions are as follows:（1）Determine the working principle and structure of the buckwheat-filled centrifugal seed metering device.Buckwheat internal seeding centrifugal seed metering device uses centrifugal force to complete seed filling,seed protection and seeding during the work process;the seeder is mainly composed of seeding shaft,seeding wheel,seed blocking sleeve,seed tube,and seed limiting box,Support frame and seed box.（2）Determination of performance parameters of key components of the seed meter.According to the force analysis of the seed in the seeding wheel under different conditions,the inner diameter of the seeding wheel is 200mm and the inner diameter of the seed blocking sleeve is 206mm.According to the physical characteristics of the seed,the hole diameter of the hole on the seeding wheel is determined as 8mm,depth 3mm,and hole thickness of the seed cover 4mm;Force analysis of the movement of the seeds in the seed-limiting box;Analysis of the movement of the seeds when they are being ejected to obtain the seed holes and the direction of gravity The included angle is 30 ° and the length is 37mm.（3）Single factor and orthogonal experiments.Through single-factor tests,it is determined that the speed that meets the requirements of the performance index is 150～190r·min^-1,the number of single rows of seed resistance sets is 3 holes,6 holes and 12 holes,and the speed of the seed bed is 4～9km·h^-1.According to the single factor test,the average displacement also increases with the increase of the seeding shaft speed;the variation coefficient of the consistency of the displacements of each row increases first and then decreases,the highest is 12.29% and the minimum is 0.221%;the total displacement The coefficient of variation of consistency showed a general downward trend,but the coefficient of variation slightly increased from 170 to 180 r·min^-1,the highest was 3.81% and the lowest was 0.706%;the seed fragmentation rate continued to rise,and when the rotation speed was110 r·min^-1 The crushing rate is 0.15%,the speed reaches 200 r·min^-1,and the crushing rate can reach 0.79%.With the continuous increase of the number of single row holes in the seed cover,the displacement is increasing and the variation coefficient of the total displacement consistency is decreasing..With the continuous increase of seed bed speed,the variation coefficient of uniformity of seeding volume also gradually increased.Use SAS to perform variance analysis on the experiments that affect the displacement,and determine that the rotation speed,the number of single row holes in the seed block,and the speed of the seed bed have a significant effect on the displacement.According to the range method,the order of influence on the variation coefficient of the seeding uniformity is determined by the number of single rows of seed block,the speed of the seed bed,and the speed of the seed row.The optimal combination is the 12-hole block,160 r·min^-1 seeding speed and conveyor speed of 5km·h^-1（4）Use ANSYS to perform static analysis on seeding shafts and assemblies.Through the static analysis,the cloud diagrams of stress,strain and actual deformation are obtained.By analyzing the cloud diagrams,it can be known that the maximum values of the stress,strain,and actual deformation of the seeding axis are 5.5737 Mpa,2.926e-5,0.00047984mm;The maximum value of the stress,strain,and actual deformation of the assembly is 43.97Mpa,0.00021276,and 0.44904mm,and the structural strength meets the design requirements.The buckwheat internal seeding centrifugal seed metering device has a simple structure and a small volume,and can be adapted to work in mountainous areas and communities.At the same time,the seed metering device has a 12-hole,160r·min^-1 seeding shaft speed,9km·h^-1 Coefficient of variation of sowing uniformity at conveyor speed is 34.91%,which is better than the performance index requirements to achieve high-speed operation.Compared with the existing seeder’s working speed of 4～6km·h^-1,it achieves high-speed operation and greatly improves the seeding efficiency.The research and development of the buckwheat-filled centrifugal seed metering device is of great significance to promote the industrialization and large-scale development of miscellaneous grains and improve the mechanization level of miscellaneous grains production.