Design And Experiment Of Threshing Teeth Single Acting Variable Diameter Threshing Drum For Grain Combine Harvester

The threshing device is the core component of the combine harvester,and its performance will affect the overall operation effect.During the harvesting process,the traditional combine harvester changes greatly due to plant growth,moisture content,etc.,which makes the threshing device poorly adaptable,unstable operation performance,and difficult to achieve the best performance.In view of the limitations of the traditional threshing device,a variable-diameter threshing drum was developed to enable the threshing device to adjust the elongation of the threshing gear rod to adjust the threshing gap,and to improve the working performance of the threshing device of the combine harvester.The main work is as follows:(1)Summarize the combination of four threshing gear rods with different elongation,and analyze the different threshing spaces formed by various combinations.The research provides a basis for the structural design of the gear rod single-action variable-diameter threshing drum.(2)Through in-depth exploration of the existing reducing mechanical structure and the principle of non-standard automation,the overall plan of the rack single-action variable diameter threshing drum including the drive device,the elongation adjustment device,and the electronic control adjustment device is designed.The PLC-based multi-sensor closed-loop control scheme has completed the corresponding program design.After the gear rod single-action variable diameter threshing drum was processed and assembled,a functional test was carried out to verify the feasibility and accuracy of the elongation device.(3)Analyze the static characteristics of the threshing drum under working conditions through ANSYS simulation,calculate the stress and strain of the threshing drum,check the reliability of the mechanism,and improve the structure of the single-action variable-diameter threshing drum according to the finite element analysis results After optimization,the maximum equivalent stress of the optimized threshing drum is reduced by 20.6%,and the maximum deformation is reduced by 32.6%,which improves the reliability of the structure.(4)Install the rack-bar single-action variable-diameter threshing drum to the combine harvester for field performance test to verify the reliability and stability of the threshing drum.Through multiple sets of field experiments,we compare the threshing performance indexes of different threshing spaces,such as grain breakage rate,entrainment loss rate,and unremoved rate,and explore the influence of different threshing spaces on the performance of the threshing device.The test results show that the development of the threshing device is variable.The diameter threshing drum has a stable structure,works normally,and can have better operating performance.The variable diameter threshing drum is used for different feed rates,and a reasonable threshing gap is selected.Compared with the traditional threshing drum,the entrainment can be reduced by 6.73% at the maximum.Loss,reduce 42.4% of broken kernels,and reduce about 50% of uncleaned kernels.