| The planting of leeks is increasing day by day,the annual harvest 3-4 times,the harvest is laborious.At present,mainly by artificial harvest,mechanized harvesting of leeks is urgently needed.Therefore,this article in-depth analysis of planting and harvesting agriculture requirements of leeks,on the basis of analyzing the leek harvesting machinery at home and abroad,A leek harvesting device was designed to meet the greenhouse conditions,Improve harvest efficiency,save labor costs,reduce labor intensity.The research contents and achievements of this paper are as follows:(1)Mechanical characteristics analysis of leek.The test shows that the shear force increases first and then decreases as the loading distance increases.The mean value of the maximum shear force of all samples is 128.8N,which provides data support for the design of the cutter part and ensures that the cutter can cut off and do not damage the leeks.The extrusion pressure increases with the increase of extrusion distance and the maximum destructive force,with the average value is 263.96 N,The maximum clamping force of chives conveyed by primary conveyor belt is 76.2N,indicating that the conveyor belt will not damage leeks in the conveying process and meet the design requirements.(2)Design of leek harvester overall scheme,the leek harvester mainly consists of the power part,the support part,the cutting part,the conveying part,the frame part,the collection box and so on.According to the working principle and working process of the leek harvester,the structural parameters of leek harvester are presented and the value range of working parameters is determined.The cutting width B is 0.25 m,the wheelbase is 260 mm and the wheelbase is 460 mm.It is confirmed that two 12 V and 42 Ah lead-acid batteries are selected in series as the power supply.(3)Design and analyze the key parts such as the cutter part,the support part,the rear handle and the conveying part,and conduct finite element analysis of the machine cutter,the connecting shaft of the cutting device and the whole machine;Determine the parameters of the cutter: 250 mm in diameter,5mm in thickness,80 saw teeth,24°edge Angle,and 120.0?300.0 r/min in cutting speed;Parameters of first-level conveyor belt: length 1.8m,width 100 mm,installation Angle 40°,relative linear speed greater than 2.25m/s;Parameters of secondary conveyor belt: length 700 mm,width 440 mm,installation Angle 20°,minimum speed 0.64m/s.(4)Performance test of leek harvester prototype,test determine the operating speed,cutting speed and cutting height of the machine as the influencing factors.With lodging rate,loss rate as the evaluation index to carry out the test.Single factor test,determine the operating speed has a great impact on lodging rate,the loss rate reaches the optimal value when the cutter speed is 220r/min,under ideal conditions,the smaller the cutter height,the better.But because of soil resistance,comprehensively to determine the cutter height must be considered;Quadratic regression orthogonal rotation combination test,for the lodging rate,the three factors affect the primary and secondary order successively: A operating speed >C cutter height >B cutter speed;For the loss rate,the three factors affect the primary and secondary order: B cutter speed >A operating speed >C cutter height;The optimal parameter combination is determined as follows: operating speed is 1.1km/h,cutter speed is 220r/min,and cutter height is-2.0cm.The test were verified and the results showed that the harvesting agronomic requirements of leek were met. |
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