Optimal Design And Experimental Research On The Header Of Corn Combine Harvester

Corn is the largest grain crop in China,and its planting area and yield rank first in China.Corn mechanized harvesting is a key link in the whole mechanization of corn.As a key component of corn harvesting machine,cutting table affects the harvesting mode,harvesting quality,operating efficiency and performance of corn harvesting machine.Direct grain harvesting can reduce the labor intensity of farmers and improve the working efficiency,which is the development trend of corn harvesting.Due to climate reasons,when corn enters the harvest period,its grain moisture content is more than 25%,which leads to too high grain fragmentation during direct harvest,which restricts the development of corn harvesting mechanization in the southern region.In this paper,the agronomic characters of corn in Hunan are studied,and the corn cutting table is optimized and tested.The main research work and contents are as follows:（1）The agronomic characters of corn in southern China were studied.The bending resistance,compression and cutting of corn stem were tested.The mixed threshing test of stem,leaf and ear was designed,and the feasibility of direct grain harvest under the condition of high moisture content was preliminarily studied.The field performance test of the original cutting table is carried out to provide reference for the optimal design of the cutting table.（2）Based on the function of the cutting table,the structure of the cutting table is analyzed,and the key components of the cutting table are analyzed.The relationship between the moving parameters of each component is determined,and the corresponding mathematical model is established.The whole structure of the cutting table was checked,and whether it could meet the requirements of corn harvest was tested.The parameters and structure of reel,scion plate and cutter were determined.（3）It analyzes the reason of the resonance and the condition of avoiding the resonance,and calculates and analyzes the exciting frequency of the main working parts of the harvester.It carries on the modal analysis of the frame,and analyzes the platform and the frequency of the first six modes.It compares the relationship between the exciting frequency of the relevant working parts and the natural frequency of the frame of the cutting table,and concludes that there will be no resonance between the exciting frequency and the natural frequency of the cutting table during the working process of the optimized cutting table.（4）Using the Design-Expert software to design the surface response test,the influence of the horizontal position,the height,the speed and the height of the cutting tool on the harvesting effect of the cutting table is explored.The optimum working parameters of the cutting table under the test conditions are as follows:the height of the cutter is X1=150 mm.The height from elastic claw tip to the cutter is X₂=110mm.The horizontal position of the reel is X₃=750 mm,and the rotational speed of the reel is 48r/min.The predicted value of each evaluation index under this parameter is obtained.The reliability of the model is verified by experiments.Compared with the experimental data of the original cutting table and the optimized back cutting table,the field ear drop rate of the key evaluation index was reduced by 19.91%,which indicated that the reduction effect of the optimization scheme of the cutting table was remarkable.