Design And Experimental Research Of Oil Sunflower Combine Harvester Threshing Device

In order to effectively increase the output of oil sunflower seeds and ensure the economic benefits of farmers,the current domestic oil sunflower combine harvester threshing device has problems such as low oil sunflower removal rate and high seed damage rate.This article summarizes the domestic and foreign oil sunflower combined harvesting.On the basis of the current mechanical research,combined with my country’s national conditions and the agronomic requirements of oil sunflower planting,a threshing device based on the oil sunflower combine was designed and developed.Based on the research on the material characteristics of oil sunflower,the overall design scheme of the threshing device of oil sunflower combine harvester is proposed.Taking the key components of the oil sunflower threshing device as the research object,carry out key component design,simulation analysis,prototype production and experimental research.The main research contents are as follows:(1)The study on the material properties of oil sunflower pan and its grains and the mechanism of grain damage have been carried out.Two oil sunflower varieties,"Youkui No.5" and "Dwarf DW667" were selected as test samples,and the geometric characteristics were determined.The ratio of the length to the width of the two oil sunflower seeds was approximately 2.34 and 2.32,respectively.The kernel model is simplified as an ellipsoid.The compression performance test of oil sunflower seeds showed that the oil sunflower seeds exhibit high elasticity when the moisture content is high,and high brittleness when the moisture content is low,and are easy to break.When the moisture content is 17%,elastic deformation occurs first and then plasticity occurs.Deformation,at this time the maximum breaking force reaches its extreme value.(2)The design of the key components of the threshing device of the oil sunflower combine harvester was carried out.According to agronomic requirements and preliminary research,an oil sunflower threshing device based on the 4LZK-2.5Z oil sunflower combine harvester was designed,and the overall operating characteristics and basic technical parameters of the device were clarified.Based on the Hertz theory,the theoretical study on the damage mechanism of the kernels has concluded that when the threshing element collides with the oil sunflower kernels,the larger the maximum and minimum radius of curvature in the normal direction of the contact area,the critical point of mechanical stress crack damage is formed.The higher the speed,the smaller the possibility of kernel damage,and the grain rod is selected as the threshing element.In addition,the structure design and analysis of the threshing drum,concave screen and top cover are carried out,and the diameter of the threshing drum is 640 mm,the total length of the threshing drum is2041 mm,the drum speed range is 208～418r/min,and the threshing gap is 12～42mm.Designed three kinds of web forms in the threshing section to install 6,4,and 3 rod teeth respectively;through statics and modal analysis,the strength of the threshing drum designed to meet the requirements of use and meet the safe operation of the oil sunflower combine harvester condition.In view of the separation effect and economic considerations of oil sunflower seeds,the grid type concave sieve is selected,and the design wrap angle is180°.According to the movement characteristics of the oil sunflower,the structural parameters of the top cover are obtained,that is,the lift angle of the spiral blade is 20°,the height is 35 mm,the blade pitch is150 mm,and the number of spiral blades is 11.(3)The field test of the threshing device of the oil sunflower combine harvester was carried out.Further through the field single factor experiment to determine the value range of the test factor,it is concluded that the speed of the threshing drum is 240～360r/min,and the range of the threshing gap is 18～30mm.The number of rack roots,the rotation speed of the threshing drum,and the threshing gap were selected as the experimental factors,and the oil sunflower pan removal rate and grain damage rate were used as the experimental indicators to carry out the field orthogonal experiment.A better combination was obtained and field verification experiments were carried out.That is,when the number of gear rods is 4,the drum speed is300r/min,and the threshing gap is 24 mm,the average removal rate of oil sunflower pan is 98.16%,and the average grain damage rate is 1.92%,meeting the field operation requirements of oil sunflower combine harvesters.