Design And Test Of Soybean Thresher Single Plant

In 2018,China's soybean production was about 16 million tons,and breeding soybean required about 450,000 tons per year.Global soybean production is about 250 million tons.At present,soybean production in China is facing technical problems such as low yield per unit area and poor sowing precision.Developing soybean breeding machinery is helpful to solve these problems,while ordinary soybean harvesting machinery can not meet the requirements of breeding soybean harvesting.In order to meet the requirements of breeding,it is of great significance to develop a single-plant thresher for soybean,which can reduce the mixing among varieties,improve the purity of varieties,reduce the breakage and improve the quality of varieties.The soybean thresher per plant should meet the following technical requirements:convenient and safe feeding,low threshing crushing rate,convenient cleaning and convenient parameter adjustment.To this end,this paper carries out the following research contents:(1)Overall design of soybean thresher per plant.The design of the whole machine includes threshing,cleaning and transmission parts.Combining threshing and transmission parts,the overturning cleaning structure is designed.The effects of detachment elements and threshing clearance on the breakage rate were studied.The diameter,rotational speed and concave screen of the threshing drum suitable for single soybean plant threshing were designed to improve the quality of detachment and reduce the breakage rate.The air suction cleaning device is used to study the suitable cleaning passage to improve the cleanliness.Reasonable threshing drum turnover mechanism is designed to facilitate cleaning after threshing and reduce the mixing among varieties.(2)Simulation and analysis of soybean grain movement process based on EDEM.Based on the simulation results,the relationship between the shape of miscellaneous opening and the smooth feeding and spattering of grains was studied,and the structure of miscellaneous opening was optimized to solve the problem of feeding and spattering of grains.(3)Parameter optimization test of soybean thresher per plant.The bench performance test includes single factor contrast test and response test.The hardness and shape of tooth profile were tested by single factor test,and the feeding amount,rotational speed of threshing element,clearance between threshing element and screen were analyzed by three-factor three-water Box-behnken response test.The crushing test results show that the crushing rate of plate teeth is 0.689% compared with that of archteeth,which is 4.59%.The crushing effect of plate teeth on reducing grain crushing is outstanding.In the tooth hardness test,the crushing effect of rubber plate is 0.10%,iron plate 1.46%,nylon plate 1.31%.The crushing effect of rubber plate on reducing crushing rate is outstanding.In the response test of plate-size rubber plate,the crushing effect is very little.In the untreated analysis,the contribution rate of drum speed is the largest,followed by clearance and feeding quantity.The use of plate-toothed rubber plate threshing element greatly reduces the crushing rate.Prototype optimization test.According to the rotational speed of threshing element,clearance between threshing element and screen mesh and hardness of threshing element,three factors and three levels orthogonal test were carried out to obtain the optimum parameters of crushing: rotational speed 498 r/min,clearance 18 mm,and material of threshing element is rubber.(4)Research and analysis of threshing process of high-speed camera and Phantom trajectory analysis and calculation.The whole,upper and lower parts of the experimental prototype were photographed to obtain the threshing process map.According to the relevant images,it was found that some plants were stuck in the feeding entrance.The shape of the threshing drum was surrounded,and the structure of the feeding entrance slideway should be further optimized.A high-speed camera was used to capture the trajectory of rubber plate with grain impacting plate teeth.The maximum velocity was12.14m/s and the minimum velocity was 2.3m/s by Phantom image analysis software.According to the change of weight and impact velocity of beans,the maximum impact energy of single beans was calculated to be 0.01518 J.