Research And Development Of Key Technology And Equipment For Threshing Device Based On Direct Harvest Of Corn Kernels

Corn is my country’s largest food crop,with a wide range of cultivation and many applications,which is of great significance to the entire national economy.Corn harvesting is the last process in the production process,and mechanized harvesting has become the mainstream harvesting method.In the mechanized harvesting process,corn kernel threshing is an important part.Due to the different physical and mechanical properties of corn varieties and corn ears during harvest,the grains will be broken and lost during the harvesting process,resulting in food waste.The threshing and separating device is the core working part of the harvester,which affects the harvest quality and efficiency.Therefore,this article uses this as the main line to explore the physical and mechanical properties of corn,innovatively design a threshing separation device,conduct experimental research,and obtain the optimal parameter combination.The main content of this article is as follows:(1)Research on the physical and mechanical properties of corn.Divide the whole corn ear into four sections,and test the geometric parameters of the whole ear and the ears of each section;the connection between the stalk of the corn kernel and the corn cob and the connection with the corn cob in the form of no kernel support and kernel support The middle part of the grains is subjected to mechanical tests to analyze the changes in the connection stiffness coefficient,the disengagement force and the disengagement displacement under each test condition,which provides a parameter basis for the design of the threshing and separating device and the operation of the simulation program.(2)Analysis of single longitudinal axial flow threshing mechanism and design of threshing separation device.Explore the four processes of single-longitudinal axial flow threshing and possible loss and damage.Using Hertz elastic contact mechanics theory,the mechanical static analysis of corn ears and threshing drums,corn kernels and threshing elements during the threshing process is carried out to explore the effects of ear kernel break Based on the critical speed,maximum contact force and maximum deformation,the threshing separation device is innovatively designed;the length of each section of the threshing drum and the form of the threshing element are determined,and the combination of bar block and nail tooth is selected,and the arrangement method is adopted The four-head spiral line is arranged,and the size of the threshing element and the spacing between the elements are determined;other key components of the threshing separation device are optimized.(3)Verification of bench test and simulation test.The mobile threshing test bench of the research group is equipped with a threshing separation device for single-factor tests.The test factors are feed amount,drum rotation speed,concave plate gap,drum inclination,and the test uses the breaking rate and the removal rate as indicators to explore the threshing performance of different factors.The effect of performance,and find out the optimal working range of each factor,carry out orthogonal experiment in this interval,establish regression model,and obtain the optimal working parameter combination of feeding amount,drum speed,and concave plate gap to be 9.12kg/ s,429.85r/min,49.07mm;the response surface analysis shows that the test results are in good agreement with the regression model;the Agri DEM simulation software developed by Professor Yu Jianqun’s research group is used for simulation verification tests,and the regression model predicts the value In comparison,it is found that the optimal interval of the drum speed and the recessed plate gap is basically consistent with the optimal working parameters of the regression model,and the value of the crushing rate and the removal rate are compared with the predicted value of the regression model,and the error is small.The reliability of the regression model is verified.