Research On Threshing Device Of Dried Green Zanthoxylum Based On Branch Picking

At present,the mechanization degree of the whole process of green Zanthoxlum production is not high,especially the relevant production equipment for picking dried green Zanthoxlum after piles is still relatively lacking.This paper mainly focuses on the threshing-related operation process of green Zanthoxlum after picking and drying in Chongqing area,and studies the threshing equipment with better threshing performance,compact structure and good economy.Based on the research on the material characteristics of green Zanthoxlum after picking and drying,a threshing device for green Zanthoxlum threshing was designed,which provided a theoretical and technical reference for the mechanization of green Zanthoxlum threshing.The main research contents and conclusions are as follows(1)According to the current harvest characteristics and agronomic requirements of green Zanthoxlumcorns in Chongqing,the material characteristics of green Zanthoxlumcorns after picking and drying were studied.The geometric and physical characteristics of the obtained part of the material are: the average length of the branches is 551.9 mm,the average diameter of the big end is about 8.34 mm,the moisture content of the green Zanthoxlum is about 8.71%,the thousand-grain weight is about 19.99 g,the average particle size is about 3.8 mm,the Zanthoxlum thorns are wide The average length is about 8.8mm,and the connection force between fruit and stem is about 2-6 N.On this basis,the overall scheme of the threshing device is designed: the whole machine is divided into two lines,the feeding drum,the threshing shaft,and the conveying and separating device,in the form of chain transmission to realize the transmission of the whole machine.Form,the threshing element uses a steel wire rope to connect the nylon sleeve,and the form of the flexible connection between the steel wire rope and the rotating shaft determines that the structure of the conveying and separating parts is the form of a mesh conveyor combined with a crank and rocker mechanism.Working parameters: the structural size of the whole machine is 2260×1200×1500(unit is mm),the power is 2-3k W,the working width is 0.9m,the reference speed of the telescopic grilling roller is 8.3r/min,and the conveying speed of the conveyor is 8-16 m/ min.(2)The structural design of key parts such as feeding parts and threshing parts.The kinematics and dynamics analysis of the telescopic tooth,the main executive part of the telescopic tooth grilling roller,is carried out.Through theoretical analysis,the speed and acceleration information of the telescopic tooth,as well as the mathematical relationship model between its force,structure size and material characteristics are obtained.Design the telescopic tooth arrangement form of the feeding part,analyze the phase of the eccentric shaft in the quadrant,and design the eccentric phase angle to be260°.Considering that the telescopic tooth is the main actuator and the direct contact with the material is relatively large resistance and the rotation speed is low,it is verified by static simulation.When the free end is subjected to the limit working condition resistance of 350 N,the maximum stress is between the tooth end and the The joint of nylon parts is 197.22 MPa,which is less than the yield limit of Q235,which meets the strength requirements;the threshing parts are designed,considering the structure and layout of the threshing elements,and the relationship between the threshing elements and green Zanthoxlumcorns is established based on Hertz theory.The mathematical model of contact mechanics,considering the strength of the green Zanthoxlum and the adjustable speed range of the threshing element,ruled out the possibility of crushing and damage to the green Zanthoxlum caused by excessive speed,considering the i MPact factor of the threshing element,the minimum speed of the threshing shaft is determined by The connection force of the stalk is preliminarily determined,and its connection force is 2-6N.Through calculation,the minimum speed of the threshing shaft is determined to be 100r/min.After selecting the motor,sprocket chain,etc.,the actual maximum speed of the threshing shaft is 258 r/min..The design and analysis of the conveying and separating parts and frame are carried out,and the crank rocker mechanism is determined as the main form of the separating mechanism.The modal analysis of the constrained conditions of the frame shows that its 1st-6th order natural frequency is 20-55 Hz,which is quite different from the vibration frequency of other moving parts in the work,and the structure meets the requirements related to function and strength.(3)Trial-manufacture and assemble the prototype according to the threedimensional model.Through the preliminary experiment and preliminary research,the rotational speed range of the threshing shaft is determined to be 100-250 r/min.After the prototype assembly of the threshing device,the preliminary experiment was carried out to study the influence of the threshing speed and the input speed of the conveyor on the threshing performance.The test shows that when the threshing speed is 150 r/min,a higher cleaning rate can be achieved,and the increase of the speed will reduce the threshing speed.Increase the impurity content of green Zanthoxlum after threshing.When the input speed is 13m/min,it can achieve sufficient threshing and high removal rate.If the speed is too low,it will increase the impurity content of green Zanthoxlum after threshing.Through the single factor test,the reasonable working parameter ranges of the threshing speed and the input speed are respectively: 140-200r/min,13-16m/min.Finally,a three-factor three-level orthogonal experiment was carried out on the threshing speed,input speed,and threshing element of the threshing device,and a quadratic regression model was established between the comprehensive score of threshing performance and the form of threshing speed,input speed,and threshing element.The reliability of the fitting equation was relatively high.good.Taking the comprehensive performance score close to 100 as the response value,combined with the test verification,the optimal working parameters of the threshing device are determined as follows: threshing speed is200 r/min,input speed is 13 m/min,segmented threshing element,and the verification test obtains the average value of the threshing device.The comprehensive performance score is 96.2,the average removal rate of green Zanthoxlum is 96.46%,and the impurity rate is 5.07%,reached a better level.