Research On Variable Spacing Mechanical Precision Seed Metering Device

At present,owing to the difference of location,structure,production mode and operation habits,the use of demander used in the current operation in China has led to the phenomenon of "soil and water disagreement" in some mechanical drive seeding metering devices,which can not achieve a better level of operation.Seed fragmentation,poor uniformity and rotation are common problems.Low speed,different sizes of seeds need to replace parts and other defects.Research and development of a mechanical precision seeder can be applied to precision seeding of various varieties and seeds of different sizes with only a small number of spare parts.It can improve the adaptability of the seeder,on the basis of satisfying the performance of the seeding on demand,the "six precision techniques" of different grain size crops in the cropping industry of the Corps were gradually realized.Based on the extensive understanding of seed technology of precision on demand planter in China,this paper takes seeds of different sizes as the research object,and makes a systematic study on cotton seed precision on demand planter from the overall scheme of precision on demand planter,seed metering mechanism of precision on demand planter,key components of precision on demand planter,etc.A kind of "one machine multi-purpose" disc-type precision on-demand seeder is developed.The precision on-demand seeder is a kind of mechanical on-demand seeder.The precision demander belongs to one kind of mechanical demander was designed and experimented.The research contents and achievements of this paper include:In view of the present situation of cotton precision seeding technology in the Corps,a mechanical precision seeder which can not only realize precision on demand seeding,but also prevent misplacement of next seeding is designed and completed on the basis of fully considering soil characteristics.The seeder is equipped with replaceable seeding wheels in the inner part of the seeder.On the basis of optimizing the design of key parts,the suitable seeding is completed.Mechanical precision VOD required by industry.(1)overall design of hill drop planterTaking the seventh division as an example,taking full account of the cotton sowing requirements and soil characteristics of the seventh division,a general scheme of mechanical precision on demand seeder was determined,which can realize precision on demand and prevent seeding from dislocation.The seeder is mainly composed of two modules,namely,replaceable seeding wheel,module clamping ring and so on.(2)design and simulation optimization of key partsOn the basis of determining the overall scheme,EDEM particle simulation technology is used to determine the ideal structural parameters.Through the design of key parts such as replaceable seed wheel and module clamping ring,the modeling of relevant parts is completed,and the simulation analysis is carried out to determine the working parameters of key parts and the selected materials;the structure and dimension of key parts and hole of seed metering device are designed and determined,and on the basis of the design,trial production of the demand seeder is made.(3)system integration and performance testThe prototype test was carried out using JPS-12 computer vision precision metering device test bench of Northwest Agricultural Equipment Key Laboratory of Ministry of Agriculture.The test factors were the linear speed of sowing belt,the number of holes in the metering plate and the three-axis size of different cotton seeds.Price index,through the use of Design-Expert software,designed three factors and three levels of Box-Behnken experiment;through the establishment of multiple factors and response indicators between the regression equation,complete the model improvement,and finally get the impact of various factors on seeding performance indicators.Taking Xinluzao 42 as an example,the optimal combination of the factors satisfying the response function was obtained,that is,when the linear velocity of the sowing belt was 0.9 m/s and the number of holes in the seed tray was 15 holes,the qualified index of the variable spacing mechanical precision seeder was 0.41,the replay index was 0.50,and the missing seeding index was 0.084.Field experiments show that the precision seeding quality of different size grades can meet the requirements of precision sowing under the condition of 35 r/min working speed and 4 km/h advancing speed.