Design Of Shovel-chain Type Low-laying Peanut Harvester And Performance Test Of Conveying And Laying

Peanut is an important oil crop in China and occupies an extremely important position in the development of China’s agricultural sector.At present,the mechanized harvesting of peanuts mostly adopts two-stage harvesting methods,including digging,drying,picking,and other works.As the primary link in the peanut harvesting process,the effect of digging operations directly affects the quality of peanut products.After years of research and development,China’s peanut harvesting mechanization level has been continuously improved,but there are still problems such as high power consumption,serious soil carry,and poor quality of strips,which affect the development of the peanut industry.Given the above problems,this paper starts with the shovelchain peanut harvester,studies and analyzes the principle and structure of the key devices of the machine,designs a low-laying shovel-chain peanut harvester,and conducts relevant experimental studies.The main research contents and conclusions of the paper are as follows:(1)Experimental study on physical and mechanical properties of peanut plants.Including the test of peanut plant traits,the test of peanut stem tensile strength,and the test of peanut plant centroid position determination.The differences of plant traits among different varieties were analyzed,and the range of related parameters was determined;The experimental study obtained that the tensile strength of each node of peanut stem was proportional to the moisture content;The measurement calculated that the position of the centroid of the plant was below the center of the whole plant and shifted to the root side as the soil mass increased.(2)Study on key devices and overall scheme.The characteristics of each working device of the existing peanut lifter were analyzed and compared,and the overall design scheme of the machine was proposed,including the machine structure,working principle and transmission system.(3)Design of digging and crushing device.The digging method of the "side-bottom-side" minimum rectangular cross-section was determined.The working width was designed to be880 mm,and the digging depth was 110～150mm.The main design parameters include: the diameter of the through shaft circular coulter was 520 mm,the digging shovel entry angle and sliding angle were 24° and 35° respectively,the extrusion shrinkage ratio of the crushed soil board was 0.56,and the spacing between the crushed soil separation grids was 60 mm.The position of the bevel-shaped extrusion feeding roller was adjustable,the speed ratio was 1.8,and the diameter was 200 mm.(4)Design of conveying and removing soil and laying device.The conveying and laying device of this machine was designed in the front-up and back-down type,which can realized the low-laying longitudinal laying of the back root of the peanut plant overlapping the front seedling of the plant.The designed conveyor chain lift angle and descending conveying angle were 27°and 15° respectively,the chain rod spacing was 67 mm,the conveying tooth height was 30 mm,and the angle between it and the chain plane was 80°.The amplitude of the three-roller active type jitter wheel was 30 mm,the vibrating wheel amplitude was 20 mm.The staggered distance between the laying roller and the conveyor chain was 20 mm,the back inclination angle of the blade was20°,and the radius of the laying grid was 700 mm.Through the kinetics analysis of peanut plants,the influence rules of the motion parameters of various devices on the soil removal,transportation and laying work of the equipment were obtained.(5)Conveying and laying performance test.The single-factor test and the three-factor threelevel orthogonal test were carried out on the conveying and laying performance of the prototype respectively.Through the response surface analysis method,the influence law of the speed of the jitter wheel,the speed of the conveyor sprocket,the speed of the laying roller,and the interaction among the three on the fruit-drop rate and the longitudinal laying rate was studied.By determining the relevant constraints,the optimal working parameters have been solved: the speed of the jitter wheel was 140r/min,the speed of the conveyor chain was 145r/min,and the speed of the laying roller was 140r/min.The testing effect was good,the fruit-drop rate and the longitudinal laying rate were 1.05% and 96.3% respectively,which met the operation requirements.