| Rapeseed is the largest oilseed crop in my country,and its planting area and total output rank among the top in the world.The middle and lower reaches of the Yangtze River are the main producing areas of winter rapeseed in my country.In this area,there is a lot of rain,the soil is sticky and hard,the surface straw remains high,the residual amount is large,and deep fertilization is difficult.Problems such as hanging grass,blocking between shovel and shovel,etc.,it is difficult to ensure a good quality of seed bed.Combined with the agronomic requirements of rapeseed direct seeding,the rotary tillage and deep fertilization components of the rapeseed direct seeding machine were designed,and the field operation effect test of the components was carried out.The main research contents are as follows:(1)Aiming at the complex working conditions before the rapeseed direct seeding operation and the problems existing in the operation process,combined with the agronomic requirements of rapeseed direct seeding bed finishing,a rotary deep-shallow rotation,positive deep fertilization and rotary tillage components combined with deep fertilization components to actively prevent clogging are proposed.The operation plan of tillage and deep fertilization clarifies the structure and technical parameters of the components of rotary tillage and deep fertilization,and expounds its working principle,transmission scheme and working process.(2)Design and parameter analysis of the key components of the deep-shallow-rotation combined seed bed preparation device of the rape seeding machine.Mainly includes:(1)The operation performance of forward rotation and reverse rotation tiller was compared,the operation mode of reverse rotation tillage was determined,the movement of reverse throwing soil was analyzed,and the movement trajectory of soil and the critical condition for realizing back throwing were η>π/2;(2)The structural design of the combined rotary tiller roller with deep and shallow rotation was carried out,and the cutter cylinder type cutter shaft with a diameter of 150 mm was selected,and the inner diameter of the rotary tiller disc was determined to be 150 mm and 270 mm.A deep-spinning machete with a turning radius of 245 mm and a working width of 45 mm is designed,a shallow-spinning machete with a turning radius of 210 mm and a working width of 65 mm,and an antiblocking straight knife with a turning radius of 310mm;(3)The structural parameters of the deep and shallow rotary scimitars are studied,and the cutting edge curve of the Archimedes helix is used.By establishing the straw cutting model of the rotary tiller,it is concluded that the optimal sliding angle of the tangential edge is 35°～55°,in order to improve the amount of soil back throwing,a 90° bending angle is designed,and the machete clearance angle is designed to be 30°.The force analysis of the anti-blocking straight knife is carried out,and the side cutting edge of the Archimedes spiral and the sharpening angle of 40° are determined.(4)It is clarified that the depth of the rotary tillage of the seedbed belt is 130mm～170mm,and the width is 100mm;the rotary tillage depth of the stubble belt is 95mm～135mm,and the width is 150 mm.arrangement design;(5)Research and design a deep fertilization shovel with a diamond-shaped structure,the fertilization depth is 80mm～100mm.The research and analysis of the structural parameters of the shovel body and the shovel tip were carried out,and it was concluded that the included angle of the diamond-shaped section was 75°,the soil-breaking edge was a sinusoidal exponential curve,and the cutting edge angle was 45°.(3)Using computer simulation technology,the optimization test and optimization verification test of the operating parameters of the rotary tillage and deep fertilization components were carried out,the drag reduction ability of the diamond fertilization shovel was verified,and the vibration characteristics of the frame were analyzed.Specifically include:(1)Based on EDEM discrete element software,a straw-soil simulation model was constructed,and the simulation optimization test of the operating parameters of the implement was carried out.By establishing a quadratic polynomial regression model and response surface analysis,the optimal operating parameter range was determined as:forward speed 1.5km/h～3.5km/h,tillage depth 140mm～160mm,rotary tillage speed345r/min;(2)In order to investigate the working effect of the machine,an optimization verification test was carried out with a forward speed of 2.5km/h,a tillage depth of 150 mm,and a rotary tillage speed of 345r/min,the optimization verification test and analysis were carried out.The test showed that the straw burial rate was 87.53%,and the error size was1.50%.The fertilization depth of the diamond-shaped fertilizing shovel 83mm～116mm.The spatial distribution of straw under the surface was analyzed,and more than 70% of the straw was distributed in the depth of 0mm～100mm,and less than 30% of the straw was distributed in the range of 100mm～150mm.The soil exchange situation after the operation was analyzed,and the soil exchange degree in the three regions reached 50% and above.(3)A comparative simulation test of two fertilizing shovels was carried out at forward speeds of 1.5km/h,2.5km/h,and 3.5km/h,and the resistance curves of the diamond fertilizing shovel and the traditional rectangular fertilizing shovel in the existing direct seeding machine were compared and analyzed.The drag reduction rate reached 9.79%,16.46% and 19.79% respectively;Using ANSYS Workbench software,the first 4-order modal analysis under constraints was carried out on the frame,and the first 4-order natural frequencies were obtained as 65.32 Hz,69.07 Hz,92.40 Hz,and 97.45 Hz.And through the field vibration verification test of the frame under different working conditions,the rationality of the frame structure design of the rotary tillage and deep fertilization components is verified.(4)Taking the rotary tillage and deep fertilization components of the rapeseed direct seeding machine as the test objects,the field conditions were measured before the test,and then a series of field tests were carried out.Mainly includes:(1)In Huazhong Agricultural University and Jianli County,a total of 5 experimental plots with obvious differences in working conditions were selected.Among them,the No.1 experimental field was weedy with a stubble height of 301 mm and soil firmness of 3233.8k Pa;and four rice stubble fields.,the stubble heights were 351 mm,364mm,513 mm,and 519 mm,respectively,and the soil firmness was 1786.1 k Pa,1825.4 k Pa,1913.3 k Pa,and 3362.5 k Pa,respectively;(2)The functional test of the machine was carried out.The operation effect of the rotary tillage components was investigated in working condition 1,and the anti-blocking ability of the rotary tillage components and the deep fertilization components was investigated in the working condition 2.The test showed that: the rotary tillage components and the deep fertilization components have achieved their respective functions;(3)The full factor quality test of the machine was carried out,and the optimal parameter combination was determined as follows: forward speed 2.1km/h,tillage depth 155 mm,rotary tillage speed 345r/min,and the tillage depth after operation at this time was 167mm(depth),126mm(shallow),the stability of ploughing depth is 91.34%,92.01%,the soil breaking rate is 91.83%,the flatness of the box surface is 14.56 mm,the straw burial rate is 93.28%,the fertilization depth is 104.6mm,and the diamond-shaped fertilizing shovel is not blocked.The requirements for seed bed preparation before live seeding of rapeseed have been met;(4)By carrying out a comparative test of the operation quality of the rotary tillage and deep fertilization components and the traditional rotary tiller,the operation effect and operating power consumption of the two machines were compared and analyzed,and it was concluded that the power consumption of the rotary tillage and deep fertilization components increased by 5.4k W,but After the operation,the ploughing depth was increased by 54 mm and 13 mm,and the stability of the ploughing depth did not change significantly.The broken soil rate and the straw burial rate were increased by 5.71% and31.41% respectively,and the flatness of the carriage surface was reduced by 5.69 mm.Rotary tillage has been significantly improved;(5)The adaptability test of high stubble surface operation shows that: after the operation in the No.4 rice stubble field,the diamond-shaped fertilizing shovel does not appear to be blocked.The stability of ploughing depth is 129 mm and 91.27%,and its soil breaking rate,box surface flatness,straw burial rate and fertilization depth reach 92.13%,16.48 mm,90.35% and 108.6mm respectively.After the operation of No.5 rice stubble field,its tillage depth reached 158mm(deep)and 118mm(shallow)respectively,and the stability of tillage depth was 87.43%and 85.97%.Reached 81.24%,22.65 mm,86.69%,the fertilization depth is 96.8mm,and all indicators reached the standard after the two working conditions. |
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