Design And Experimental Study Of The Flat Fritillary Belt Socket Type Seeding Devic

Fritillaria thunbergii belongs to intensive planting crops.The seeds have the specificity of different sizes and shapes,obvious petals and easy damage.As a result,the existing seed metering device can not realize the mechanized cultivation of Fritillaria thunbergii,which is still dominated by manual sowing.In order to solve the problem of mechanized cultivation of Fritillaria thunbergii,this paper plans to design a belt socket seed metering device suitable for the planting and agronomic technical requirements of Fritillaria thunbergii.Through three-dimensional design,virtual simulation and prototype test,the key components of the seed metering device are designed,theoretical analysis and experimental research,and the best structure and working parameters of the device are obtained.The specific research contents and results are as follows:(1)By grading the seeds of Fritillaria ussuriensis and analyzing the materials and mechanics of the seeds of Fritillaria ussuriensis,the average triaxial size of the seeds was measured as long× wide × Height: 15.5mm × 14.4mm × 12.8mm,natural repose angle is 36.4 °;The static friction angle,sliding friction angle and rolling friction angle between Xiaobei and rubber plate were28.4 °,29.5 ° and 35.2 ° respectively.The ultimate pressure loads of Xiaobei in the triaxial direction measured by the universal material testing machine are X × Y × Z:64N × 129 N × 72 n,which provides a theoretical basis for the parameter design of the whole machine.(2)According to the agronomic technical requirements of Fritillaria ussuriensis cultivation,the shape of the hole was determined as a conical cylindrical hemispherical bottom hole,and the belt hole type precision seed metering device was designed in three dimensions.Through seed filling,seed clearing,seed feeding test and edem discrete element simulation,the rationality of the hole and the whole machine design is verified,and the value range of the main factors affecting the seed metering performance is obtained: the forward speed range is 0.36 ～ 2.16km/h,the hole diameter range is 20 ～ 30 mm,and the seed feeding height range is 40 ～ 140 mm,which lays a model foundation for indoor and outdoor tests.(3)The advance speed,hole diameter and seed feeding height are selected as the test factors,and the qualified rate,replay rate and missed rate of sowing are used as the evaluation indexes to test the seed metering performance.The indoor single factor test is carried out to obtain the best value range of each factor.Based on the single factor test results,the outdoor multi factor test was carried out by using the method of three factor and three level orthogonal test.The results showed that the order of the influence of each factor on the qualified rate,replay rate and missed seeding rate was as follows: seed feeding height > hole diameter > forward speed;Hole diameter > seeding height > forward speed;Hole diameter > forward speed > seeding height.Using of software Design-Expert 10.0 software to analyze and optimize the results: when the forward speed is 0.88km/h,the hole diameter is 24 mm and the seed feeding height is 75 mm,the qualified rate is 93.16%,the replay rate is 4.22% and the missed seeding rate is 2.62%.All indexes are optimal and meet the precision seeding standard.