| As one of the main soybean production areas in China,the summer soybean yield in Huang-Huai-Hai region is second only to that in Northeast China,but restricted by topography and planting scale,the mechanized soybean planting and harvesting level in this region is far lower than that in Northeast China.Soybean production in huang-huai-hai mechanization level is low,the process of harvesting wheat combined harvester is mainly used for harvesting,based on rice and wheat combine the cut sets of altitude,speed,drum speed adjustment to adapt to the working parameters,such as soybean harvest,but the biologica l characteristics of soybean plant and agronomic parameters and the rice and wheat gap is larger,compared with the rice and wheat plants,the soybean plant soybean plant stalks coarser,soybean pod distributed in plant body,harvest,soybean grain moistur e content is low,pod is easy broken,and pod is full of the whole plant,tiny branches withered,the snags easily under the influence of the external force and pea.Appeared in the process of harvesting due to wheel is designed improper installation locat ion,wheel speed is designed with the machine speed mismatch and due to the bottom of the different varieties of soybean pod growth height,harvesting machine operation function of copying the process does not have,the minimum cutting position,will appear in the process of mechanized harvesting bottom pod leakage cut,thereby causing loss to the cutting machine,had a greater influence on the quality of soybean.In order to solve these problems,combining with the biological characteristics of soybean plants in Huang-Huai-Hai region,this paper designed and studied the low loss soybean cutting platform.The development of low loss soybean cutting platform has certain influence on improving soybean mechanization level in Huang-Huai-Hai area.The main contents of this study are as follows:1.Through the study of the soybean mechanized production process in Huang-Huai-Hai region of China,it was concluded that the high loss rate of cutting table in the soybean harvest process in this region directly affected t he improvement of the soybean mechanization level in this region.It was found that the high loss rate of cutting table existed in this region.In order to solve this problem,the research status of reducing the loss of cutting table at home and abroad is introduced and summarized,and the main ways to reduce the loss rate of cutting table are to reduce the vibration of cutting table and design the copying cutting table.Combined with the latest research results at home and abroad and the current situation of soybean production in huang-huai-hai area,this paper puts forward a design of soybean low loss cutting table,and puts forward the corresponding research content and technical route,and carries on the feasibility analysis of the research scheme of soy bean low loss cutting table.2.Research and analysis of soybean plant biological characteristics and agronomic parameters in Huanghuaihai area.Relevant data are obtained by measuring the biological characteristics and agronomic parameters of 20 diffe rent soybean plant varieties.The analysis of the data shows that the row spacing of soybeans planted in this area is 36 cm,the average plant spacing is between10.5-23.5cm,and the average plant height is 42.8.Between ～90.4cm,the average bottom pod height is between 7.8～29.8cm,and the average canopy surface diameter is between 10.5～41cm;combined with statistical results,the design requirements of soybean plant biological characteristics and agronomic parameters on soybean headers are analyzed.It is proposed to design the reel structure parameters and installation positions suitable for soybean plant characteristics,design a reasonable transmission mode,design and install the profiling system of the header;determine the matching relationship between the reel speed and the forward speed.The working principle and overall structure of the soybean low-loss header are analyzed.3.Theoretical analysis and design of key components and transmission mode of low loss cutting table.In order to reduce the im pact of the pulley on the soybean plant,the material of the pulley’s elastic teeth will be replaced by PVC material.The structure of the pulley adopts the eccentric six-rod elastic teeth pulley,with a diameter of 1000 mm and a speed of 35～45r/min.Throug h theoretical analysis,the installation height range of the pulley is determined to be 700mm～820mm,and the maximum moving distance is 196 mm.In order to reduce the impact of the vibration of the cutter on the harvest of the cutting table,the swinging ri ng box was designed to replace the crank connecting rod device,and the relationship between the cutter frequency and the machine forward speed was determined.Design and determine the related structural parameters of the cutter and the spiral gear scraper conveyor.In order to reduce the loss of plant drop caused by stopping the working parts of the cutting table when the harvester stops or reverses,a hybrid drive mode of transmission and HST is designed to make the working parameters of the cutting table change with the change of the speed.According to the growth characteristics of soybean,in order to reduce the loss of cutting table caused by missed cutting,realize the harvest of soybean with low cutting stub,and avoid the problem of cutter shovel after cutting table is lowered,the copying system of cutting table was designed to make the height of cutting table change according to the change of terrain and improve the harvest quality of low loss cutting table.4.In order to verify the accuracy of low loss cutting table profiling system,a field validation test was carried out.Four groups of tests have been carried out,the corresponding contour height value respectively take 60 mm,70 mm,80 mm and 90 mm,the test after the stubble height measuring average,stubble height and industrial Settings,in front of the test of the average profile height value of absolute error is within 2 mm,the absolute error of the small four group test stubble height variation coefficient was 7.18%,7.12%,5.23% and 5.15% respectively,the actual stubble height is stable;The profiling control precision of four groups of tests is 85%,72.5%,95% and 82.5%,respectively.The accuracy of low loss cutting table profiling system is better.5.Take the header loss rate as the test index,and perform parameter optimization tests on the operating par ameters.Through the single factor test,it is determined that the parameter range of the horizontal position of the reel and the cutter is 60mm～80mm,and the vertical position of t he reel and the cutter is 700 mm.The single facto r test analysis shows that the vertical distance between the reel and the cutter has no obvious influence on the lo ss rate of the header.Therefore,the forward speed of the harvester,the speed of the ree l and the horizontal posi tion of the reel and the cutter are used as the test factors.Multi-factor optimization,establish a regression mathe matical model of the low-loss header on the loss rate of the header,and perform variance analysis.Through calc ulation,the contribution values of each factor of the machine forward speed,the reel speed,and the reel relative to the horizontal position of the cutter are 2.05,1.48,1.81,respectively.By setting the constraint conditions on the target parameters,the optimal solution combination of the working parameters is obtained by calculation: when t he machine forward speed is 1.2m/s,the reel speed is 33r/min,and the horizontal distance between the reel and the cutter is 70 mm,the cutting The loss rate of th e header was 1.29%;in order to verify the optimal solution of th e loss rate model of the header,a field verification test was carried out.The test results showed that the loss rate of the header was1.27%,and the harvest quality was greatly improved t o meet the design requirements. |
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