Improvement Design And Experiment Of Driven Disc Plough-Rotary Combined Tiiier

Rapeseed,a crucial oilseed crop in China,stands out as one of the most productive oilseed crops with respect to oil yield.Tillage is the foundation of rapeseed production.The driven disc plough-rotary combined tiller adopts the working mode of first active ploughrotary tillage,then rotary tillage,and middle ditching opening.Due to its active plough feature,driven disc plough-rotary combined tiller can efficiently complete tillage work on most soil types.However,when the previous crop residue is high and the soil is sticky,the rotary cultivation device still has issues with low soil shattering rate,low straw burial rate,and entanglement of the blade roller.In order to improve the quality of work and adaptability of the driven disc plough-rotary combined tiller,this paper proposes a modified design of the structure of the driven disc plough-rotary combined tiller,which includes a ditching-opening device on both sides of the unit and the development of a double-edged rotary cultivation device.The present study encompasses both simulation and field experiments,with the primary focus of research activities as follows:(1)Pre-test experiments were conducted on the first-generation prototype of the driven disc plough-rotary combined tiller under complex working conditions such as high previous crop residue,sticky soil,and large fluctuations in soil moisture content.During the testing process,issues are identified with the plough structure being prone to blockages,the rotary cultivation device easily getting entangled with grass,and low rates of soil shattering and straw burial after operation.In light of the reasonable construction of the tillage layer for rapeseed and the overall agronomic requirements for rice-rape or rice-rice-rape rotation,a process is proposed that involves driving the plow first,followed by the double-edged rotary cultivation device for soil shattering,while opening furrows on both sides.The basic structure and transmission method of the driven plow-rotary cultivator are determined,and the working principle of the driven plow-rotary cultivator and the double-edged rotary cultivation device are elucidated,while the main technical parameters of the entire machine are clearly defined.(2)On the basis of considering the actual farming conditions in the Mid-lower Reaches of The Yangtze River.The improved design of the driven disc plough rotary combined tiller is subjected to the analysis and design of its crucial components.The research activities,in particular,are focused on the following aspects:①Through theoretical calculation and analysis,it is determined that the diameter of the driven disc plough is 510 mm and the critical deflection angle is 27.06°and the installation spacing of the driven disc plough group is 160 mm.According to the plough principle of driven disc plough and ditching device,the interactive design of driven disc plough and ditching device is carried out.It is determined that the driven disc plough adopts the symmetrical arrangement of two left and two right and the structural layout of the ditching device on both sides.②According to the sliding cutting principle,the key structural parameters of the double-edged rotary blade with Archimedes spiral long blade and sinusoidal exponential curve short blade are determined.The force analysis of the working state of the double-edged rotary blade shows that the sliding cutting condition of the blade curve is that the sliding cutting angle is greater than the friction angle between the straw and the steel,and the polar diameter of the spiral starting point of the long blade edge curve is determined to be 164 mm.The sliding cutting angle at the end of the spiral is 60°,and the polar angle at the end of the spiral is 0.75 rad.Furthermore,the polar diameter of the inception point for the short blade edge curve is determined to be 120 mm.The static sliding angle of the starting point of the curve is 52°,and the decreasing ratio of the static sliding angle is 0.06.③The kinematics analysis of the double-edged rotary tillage device is carried out,and the rotation speed of the rotary tillage knife roller is determined to be 290～360 r·min-1.Under the motion parameters,the cutting process of the double-edged rotary tillage blade is analyzed,and the variation law of the cutting angle of the cutting edge is clarified.The blade angle of the double-edged rotary tillage blade is determined to be 20°,the installation angle is 55°,and the gap angle is 1.31°～7.33°.④The design and parameter analysis of the knife roller of the double-edged rotary tillage device are carried out.The diameter of the rotary tillage barrel is designed to be 152 mm.In consideration of both the structural arrangement of the driven disc plow group and the resulting soil morphology following disc plough operations,the doubleedged rotary tillage blades have been positioned along the double-headed spiral line.Moreover,the single-sided working width of the double-edged rotary tillage device has been determined to measure 1075 mm.(3)The performance comparison simulation experiment of double-edged rotary tillage device and the dynamic balance check simulation experiment of double-edged rotary tillage device are carried out by simulation method.The specific research contents include:①A simulation model,aimed at investigating the interaction between soil,straw,and machine,has been established using discrete element simulation.The Hertz-Mindlin with JKR model is used in the soil simulation model,and the contact parameters between the models are determined.②The working process of the double-edged rotary tillage device is analyzed.The performance comparison experiment between the double-edged rotary tillage device and the traditional rotary tillage device is carried out with the straw burial rate as the simulation experiment index.The simulation comparison experiment shows that the average straw burying rate of the whole machine equipped with double-edged rotary tillage device is 90.11%,which is 5.99%higher than that of the whole machine equipped with traditional rotary tillage device.The exchange of soil layer after the operation of the whole machine with double-edged rotary tiller and the traditional rotary tiller is compared.The DEM simulation test showed that the soil plough layer exchange degree is higher after the operation of the driving plough rotary combined tillage machine with double-edged rotary tillage device.③The MDB simulation method is used to carry out the dynamic balance check simulation experiment of the double-edged rotary tillage device.The simulation results show that the total unbalance of the double-edged rotary tillage device is 23163.2g·mm at the maximum speed of 360r·min-1,which meets the G16 design standard of agricultural machinery dynamic balance.(4)In order to assess the field performance of the driven disc plough-rotary combined tiller,both field performance experiments and field seeding are conducted,utilizing said combined tiller as the primary test object.The details of the experiment are as follows.①Two experimental fields with different soil moisture content and stubble height are selected in the rice-rapeseed rotation mechanized production demonstration base in Jianli and the parameters of the plots are measured.The average stubble height is 506 mm,the average straw amount on the surface is 3.28kg·m-2,and the average soil moisture content is 25.7%.The average stubble height is 323 mm,the average straw amount on the surface is 1.51kg·m-2,and the average soil moisture content is 33.27%.②The performance verification test of the driven disc plow-rotary combined tiller is carried out in the test plot.The test results of the working condition 1 plot after operation showed that the straw burial rate is 97.7%and the soil crushing rate is 96.2%.The comparative test of the operation performance of the whole machine and the rotary tillage rape direct seeding machine is carried out under the working condition 1 plot.The test results showed that the average soil crushing rate of the driving plow rotary combined tillage machine is 8.94%higher than that of the rotary tillage rape direct seeding machine,and the average straw burial rate is increased by 24.23%.The field performance test results of condition 2 showed that the soil crushing rate is 94.4%and the straw burying rate is 95.2%.The field performance test shows that the driving disc plow group and the double-edged rotary tillage device can effectively bury the surface straw under two working conditions,and the soil is fine and smooth after the whole machine operation.③The field seeding experiment of the driven disc plough-rotary combined tiller is carried out.The field sowing test showed that the seedbed quality of the driven disc plough-rotary combined tiller is better after operation.The driven disc plough-rotary combined tiller has good seedling emergence effect and high seedling emergence rate after seeding.The operational efficacy of the driven disc ploughrotary combined tiller is in compliance with the requisite standards for the preparation of rapeseed direct seeding beds.