| As the high-yield,adaptable and high-utility renewable tropical crop,cassava is widely planted worldwide and its planting area and harvested yield are increasing year by year.The development prospect of cassava industry is broad,however,the key factor restricting the development of cassava industry is the mechanized produce of cassava,especially mechanized harvest.At present,the development of China’s cassava harvester is still on the state of infancy,and many key and difficult technical problems have not yet been dealt with.The harvesting process of the combine harvester for cassava includes cutting stalk,excavation,separation between tuber and soil,clamping and conveying,and separation between tuber and stems.This paper studies separation and clamping device which are key devices of combing harvester for cassava,according to the current harvesting mechanism of cassava harvester.The test platform for clamping and separating device was designed,which can adapt to different varieties of cassava harvesting,have the advantage of stable clamping and conveying,cut effectivly and avoid cutting repeatedly and missing.Parameters of clamping conveying speed,cutting speed,teeth number of cutter disc and these factors combination on clamping and separation were researched.These combination parameters of factors provide a theoretical basis for the development of the cassava combine harvester.The main research contents and results are as follows:(1)Using the methods of statistical analysis and field investigation to study the biological and mechanical properties of cassava,Based on the research data on the distribution of cassava planting and the biological characteristics of cassava stalks,referrng to the separation and harvesting mechanism of other stalk crops,the working parameters and design scheme of the device on the test platform were determined.(2)Optimizing the design of the cassava clamping and conveying mechanism determines the clamping type and clamping method.Key components such as clamping wheels,compression springs,and conveyor belts were designed,selected,calculated and corrected,according to the mechanical design manual.We built its 3D model by using SolidWorks modeling software,performing ANSYS finite element analysis on key drive components.(3)We designed the cutting device of the cassava harvester and studied the relationship among the trajectory of the cutting point,the clamping conveying speed and the tool rotation speed determining the basic parameters of the cutting knives under the cutting conditions.(4)The transmission system of the whole machine,including the transmission system of the clamping conveyor and the stalk cutting device,were designed.The power consumption,transmission torque,transmission efficiency of each transmission system were calculated and selecting the motor needed to match the power model.(5)A clamping separation test platform of cassava harvester was built,carrying out a series of tests through cassava clamping and separating test platform to analyze the influence of tool type,clamping speed,cutting speed and other factors on the torque of the tool operation.The response surface analysis method was used to study the optimized combination of parameters including clamping conveying speed,cutting speed and cutting teeth number.The results which have least influence on the torque of the tool operation show that:the cutting speed of 600 r/min,the clamping conveyance speed of 2.0 m/s,cutting teeth number of 24,then the torque value of the tool operation was at least 3.2 N·m. |
