Structural Design And Experimental Study Of High Efficiency Drag Reducing Shovel For Carrot Combine Harvester

Carrot planting area and total output of China both rank first in the world,but most regions still adopt the method in which both artificial and semi-mechanical harvesting coexist.Manual harvesting has high labor intensity and low efficiency,and semi-mechanized harvesting has problems such as high economic cost,and cannot meet the requirements of large-scale carrot harvesting.As an important part of the carrot combine harvester,the existing research mainly focuses on the structural design of the shovel of subsoiler during the middle tillage period.The special shovel of subsoiler is not developed in combination with the carrot production mode and harvest agronomic requirements.Operation quality and power consumption,therefore,there is an urgent need to carry out related research on shovel matching the carrot harvesting mode,and to develop efficient and practical supporting key components.Synthesizing the above problems,this paper conducts an in-depth study on the shovel of the carrot combine harvester.In accordance with the agronomic requirements of carrot planting in Heilongjiang region,a high efficiency drag reducing shovel for a carrot combine harvester was designed,and a variety of methods and technical means in cluding comprehensive engineering bionics,theoretical analysis,computer simulation analysis,and experimental research were conducted to study the rationality of shovel.The structural parameters and the mechanism of drag reduction and interference enhancement,and verifying their working performance,are intended to provide reference for the design of the loosening parts of the carrot combine harvester.The research content of this article mainly includes the following aspects:(1)Physical properties measurement of soil and carrotCarrots of Heilongjiang black clay and "red ginseng seven-inch" were selected as research objects,and the physical properties of soil and carrots were measured using national standard test methods.Physical parameters such as soil hardness,water content,bulk density,and tensile properties of carrot roots and extraction force were obtained The relevant mechanical parameters provide a theoretical basis for the subsequent design and theoretical modeling of high efficiency drag reducing shovel,as well as the theoretical basis and boundary conditions.(2)Structrual design and analysis of high efficiency drag reducing shovelCombined with structure design and bionic technology,a bionic high efficiency drag reducing shovel was designed.A bionic drag-reducing shovel tip was designed based on the claw,and its drag-reducing mechanism was analyzed.The mechanical contact model with soil determines the blade structure parameters that affect the operation quality of the shovel as blade opening angle αand blade inclination angle β;determined by mechanical analysis of the sliding angle of the blade handle and design of surface bionic drag reduction,The sliding angle of the shovel handle is 44.5°and the height of the rib structure is 2.5mm,which ensures the drag reducing and interference increasing effect of the shovel and improves the quality of the shovel.(3)Optimal experiment of numerical simulation based on discrete element methodBased on the discrete element method,a component-soil-crop model was established and a shovel virtual simulation experiment was conducted.The operation mechanism of the shovel was explored,a drag reduction and disturbance enhancement dynamic model was established,and the wing of shovel structure parameters on the harvest process of carrots were analyzed.The influence of forward resistance and carrot extraction force;combined with the Design-Expert 8.0.6 software,the optimal parameter combination of the shovel was determined,and the working performance of the high efficiency drag reduction shovel was verified.The results show that the main structural parameters that affect the quality of the carrot combine harvester shovel are the blade opening angle α and the blade inclination angle β.When the two are 127.27° and 47.37°,respectively,the operation performance of the shovel is optimal.The forward resistance and carrot extraction force were 1908.76 N and 48.37 N,respectively.(4)Configuration design and field experiment of high efficiency drag reducing shovelThe overall configuration of the high efficiency drag reducing shovel was performed,a comparative experimental study of field performance was performed.The results show that when the machine at a speed of 0.7m/s,the high drag reducing shovel’s forward resistance is 1945.29 N,and the carrot The extraction force of carrot is 51.7N,the leakage rate is 3.1%.Compared with the chisel-type shovel,the forward drag of the high-efficiency drag reduction shovel is reduced by5.79%,the carrot extraction force is reduced by 22.84%,and the leakage rate is reduced by 3.8;It proves that the designed high efficiency drag reducing shovel can be applied to the conventional carrot mechanized harvesting process,has good comprehensive operation performance,meet the requirements of carrot mechanized harvesting operation.