Design And Experiment Research Of Pneumatic Cylinder Three-row Soybean Seed-metering Device On Ridge

In the soybean planting patterns,the close planting pattern of big ridge three rows was gradually popularized and applied in the cold region of north China.The planting pattern could not only make rational use of the area on the ridge,but also increase the utilization ratio of light energy and the yield of soybean.It can also improve the ability of soybean cultivation to resist drought and water logging,and achieve the purpose of saving cost and increasing efficiency.At present,three rows close planting soybean cultivation technique on 1.1m ridges is used in parallel connection with three single-row seed-metering device per planting unit group.This not only leads to the complex structure of planting unit group and the complicated structure of gas pipeline of seeder,but also increases the cost and reduces the planter passing ability.Therefore,it is practical significance to develop and design a kind of pneumatic cylinder three-row soybean seed-metering device on ridge matching with the three-row soybean close planting cultivation model.The research is completed under the support of the national soybean industrial technology system-the special fund for the construction of modern agricultural technology system?CARS-04-PS22?,this paper summarizes the research status of domestic and abroad pneumatic seed-metering device,analyzes the structure of the existing pneumatic seed-metering device and the advantages and disadvantages,according to the traditional soybean seed-metering device can only be achieved a single row for the operation,this study designed a kind of pneumatic cylinder three-row soybean seed-metering device on ridge matching with the three-row soybean close planting cultivation model,and through the combination of theoretical analysis,numerical simulation analysis and experimental research,the design and prototype of pneumatic cylinder three-row soybean seed-metering device on ridge have been completed.The main contents and results are as follows:?1?Based on the analysis of the research status of pneumatic seed-metering device domestic and abroad and the agronomic requirements of three rows close planting pattern for soybean on ridges.The overall design scheme of the pneumatic cylinder three-row soybean seed-metering device on ridge was determined,and its working principle was analyzed.?2?The material characteristics of the main soybean varieties in the cold region of North China were studied.The main experimental materials were Heinong 48,Heihe 43 and Dongnong 52 under the same moisture content.The size of soybean seeds,the 100-seed weight,the angle of repose were measured respectively.Internal friction angle and sliding friction angle between seeds and different materials.The arithmetic mean diameters of three soybean seeds,Heinong 48,Heihe 43 and Dongnong52,were 7.48 mm,6.27 mm,6.81 mm respectively;the 100-grain weight was 22.4 g,19.8 g,21.2g respectively;and the angle of repose was 27.3°,35.5°,32.7°respectively;the angle of internal friction is 24.9°,33.4°,31.5°respectively;the angle of sliding friction between three kinds of soybean seeds and stainless steel plate is 16.7°,14.8°,15.2°respectively;the angle of sliding friction between three kinds of soybean seeds and PVC plate is 19.5°,17.6°,18.9°respectively;and the friction angle between three kinds of soybean seeds and common steel plate is 18.2°,16.9°,16.3°respectively.The measured results provide a reference for the design of the key parts of the pneumatic cylinder three-row soybean seed-metering device on ridge.?3?Theoretical analysis on the working process of seed metering device was carried out and the key components are designed.The mechanical model of seed absorption and seed carrying process was obtained,and the factors affecting the adsorption force and the effect of the change of each factor on the adsorption force were determined.The mathematical model of seed seeding process was obtained,and the error of seeding,the ideal seed area and the absolute speed of landing position were obtained.The structural parameters of the key components of the three-row soybean seed-metering device on ridge are determined.The diameter of the cylinder is 200 mm,the length of the cylinder is 500 mm,the axial hole of the cylinder is 3 rows and the distance is 200 mm,and the number of single row holes is 40,the angle of adjacent hole spacing is 9.The sealing problem of the pneumatic cylinder seed-metering device is solved through the innovative design of the structure.?4?The numerical simulation and analysis of internal flow fluid for seed-metering are carried.Using ANSYS Workbench and Fluent software as numerical simulation tools,the pressure and velocity distribution cloud images of internal flow field are obtained by software simulation under the conditions of different spindle structure parameters combination.The internal flow field of the pneumatic cylinder three-row soybean seed-metering device on ridge was simulated and analyzed.When the axial distribution row number of the spindle is 3 rows,the diameter of the shaft hole is 14 mm,the pressure and velocity distribution in the drum is uniform.And the maximum airflow velocity is at the hole.?5?The structure and working parameters of the pneumatic cylinder three-row soybean seed-metering device on ridge were optimized by the combination of single factor test and quadratic regression orthogonal rotation center test.The main and secondary order of the influence of each factor on the quality index of seed spacing is as follows:vacuum degree,working speed,hole diameter.The main and secondary order of the influence of each factor on the multiple index of seed spacing is:vacuum degree,hole diameter,working speed.The main and secondary order of the influence of each factor on the missing index of seed spacing is:vacuum degree,working speed,hole diameter.For the main soybean varieties in the cold region of Northeast,the optimum structure and working parameters combination of the pneumatic cylinder three-row soybean seed-metering device on ridge are:the hole diameter is 4.5 mm,the vacuum degree is 4.7⁵.9 kPa,and the working speed is 6.0⁹.1 km·h^-1.and under the optimal combinations,the qualified index was more than 95,the multiple index was less than3,and the missing index was less than 2.