Design And Experimental Study On Pneumatic Cell Wheel Seedmeter For Small Size Seeds

China is the largest vegetable producer and consumer in the world,vegetable production accounts for about 60% of the world's total output.At present,the level of mechanization of vegetable production in the country around 25%,of which the level of mechanization of vegetable sowing has been far behind the level of development of the entire vegetable mechanization.Vegetable artificial planting efficiency is low,high cost,poor quality,has not adapted to the current needs of modern agricultural production,the design of a reliable performance of vegetable sowing machinery has become the urgent need to solve the problem.In this paper,based on the systematic comparison and analysis of domestic and foreign vegetable mechanization sowing technology and equipment,a kind of Pneumatic Cell wheel Seedmeter for Small size seeds was designed.The Seedmeter can effectively solve the problem of shortage of vegetable Metering device in the market,and provide some reference for the design of small size seeder.Its research has important theoretical and practical significance.The main research contents are as follows:(1)Study on mechanical properties of cabbage seed.The physical characteristics and the suspension coefficient of the seeds were determined,which provided the theoretical basis for the design of the pneumatic cell wheel seedmeter for small size seeds.The results showed that the triaxial dimensions of the seeds conform to the normal distribution,the normal distribution,in the range of 1.8 ~ 2.6mm,1.5 ~ 2.1mm and 1.2 ~ 2.0mm;The grain weight was 3.98g;the angle of rest was 25.0 °;The sliding friction angle on cast iron is 32.5 °,on ABS resin is 25.4 °;Internal friction angle 34.1 °;The suspension speed of cabbage seeds tends to be between 5.34 m/s and 6.01 m/s,and increases with the increase of grain weight.(2)Design of pneumatic cell wheel seedmeter for small size seeds.The structural parameters of the metering device were designed and calculated according to the agronomic requirements and actual physical and mechanical properties of cabbage seeds.The characteristics of the seed metering device combined with the pneumatic seed metering device and the Cell wheel metering device have solved the problem of the difficulty of filling due to the irregular shape of the small grain vegetable seed.At the same time,a kind of tooth pushing device was designed to solve the problem of hole blocking.(3)Analysis of the work process of seed metering device.Analyzing kinematic and dynamic characteristics of the seeds about filling?clearing?carrying and dropping four stages,to calculate the theoretical operating parameters required to complete the seeding device seeding process.And the trajectories of the seeds after the seeding was completed.(4)Experimental Study on the Performance of Seed Metering Device.A single factor test was conducted on the metering device with respect to negative pressure and the speed of the crescent wheel,and its influence on the seed filling performance and seed setting performance was analyzed.The results show that the filling effect is the most important factor affecting the performance of the seeder,and the seeder can meet the requirement of filling in the case of high speed seeding,and the maximum speed of the nest is about 130 r/min.At the same time,when the speed of the cell wheel is below 60 r/min and the negative pressure reaches 400 pa,the overall fluctuation range of the qualified index is less than 90% and the injury rate is less than 0.3%,which can adapt to the complicated working environment in the field.When the cell wheel rotation speed of 35 r/min,the internal negative pressure of 250 pa,the seeder pass rate of 96.3%,leakage rate of 2.0%,the replay rate of 1.7%.