| In order to promote the sustainable development of agriculture in our country,Ministry of Agriculture and Rural Affairs presented to ensure “one regulatory,two reduction and three basic”target come true in 2020.Governance agricultural non-point source pollution issues,promote resource-conserving and environment-friendly agricultural production technologies.Conservation tillage provides corresponding solutions and solves the problem of high-efficiency metering under the large amount of straw mulch surface and scientific returning of straw,therefore realize agriculture sustainable development.In February 2020,The Ministry of Agriculture and Rural Affairs and The Ministry of Finance printed and distributed the “action plan of northeast black land conservation tillage(2020-2025)”and it indicated that corn as the focus of promotion and give consideration to soybean,wheat and other crops production in three provinces in the northeast of China and some cities of the Nei Mongolia autonomous region.In order to reduce soil disturbance and soil erosion,the two technical practice of no/reduce tillage with straw mulching,at the same time appropriately increase the proportion of straw returning to improve soil organic matter.For this reason,In order to improve the quality of field work of planter and combined with the northeast agricultural university research and development of the 2BMFJ series wide coverage planter theoretical analysis and experimental study on the ground wheel assembly of seeder were carried out.In the process of field operation,the problems of unstable depth of stubble cutting and large slip rate of ground wheel were solved,the work quality of the seeder was improved.In this paper,the research contents and conclusions was as follow:(1)Specify overall design requirements for wheel assembly and analyzed the motion state and force of ground wheel.It was concluded that there were main two kinds of disturbance to the soil when the ground wheel moves,including,the forward pushing and the backward digging.To determine the mathematical model of the influence of the structure parameters of the ground w heel on the soil friction,it was concluded that the vertical load of the ground wheel,the diameter of the ground wheel,the width of the ground wheel and the soil properties were the main factors affecting the friction of the ground wheel.Designed and checked the copying mechanism of the ground wheel assembly,and determine that the upper and lower copying Angle was 12°,the traction Angle was 0°,the length of the copying rod was 480 mm,the length of the supporting plate of the ground wheel was 410 mm,and the transverse size of the copying mechanism was 160 mm.At this time,the copying amount can meet the work requirements.(2)Used Solid Works to build a 3d model of ground wheel assembly and imported it into ADAMS software and simplified the virtual prototype of the copying deep-limit ground wheel assembly.After setting parameters,the motion state of ground wheel assembly was simulated.Three factors,four levels orthogonal test method was used,of which preload,spring stiffness,operating speed were selected as factors and dynamic deflection,dynamic load of ground wheel,acceleration were as objective function.In order to reduce the dynamic load of ground wheel,reduce the acceleration as the goal,both machine efficiency at the same time,the final optimization results show that it was beneficial to reduce the ground wheel dynamic load and reduce the acceleration when the spring stiffness was 120000 N/m.(3)According to the field operation requirements of the planter,the hyd raulic system of no-tillage planter’s ground wheel and straw retaining plate was designed,and the schematic diagram of the hydraulic system was determined.According to the structure of the ground wheel assembly and the quality of the planter,the inner diameter of the hydraulic cylinder was 63 mm,the diameter of the piston rod was 35 mm,and the travel of the piston rod is 160 mm.Based on AMEsim software a simulation model of the designed hydraulic system was built.After the sub-model selection and parameter setting of each component,the simulation was carried out,and the movement state and oil flow state of the piston rod of the ground wheel hydraulic cylinder and the block plate hydraulic cylinder were analyzed to verify that the working performance of the system could meet the design requirements.According to the working requirements of the system,the man-machine interaction interface of the electronic control d evice of the hydraulic system was initially established and the control program was written to improve the intelligent level of the machine.(4)According to GB/T6973-2005 “single grain(precision)seeder test method” and GB/T9478-2005 “grain drill test method”.The results showed that the slip rate of the hydro-controlled copying deep-limit ground wheel(mode 2)was significantly lower than that of the mechanically adjusted ground wheel(mode 1)at the same operating speed,and the slip rate of the ground wheel of both modes increases with the increase of the operating speed,but the growth trend of mode 2 was less than that of mode 1.The average quality rate of stubble-cutting depth of mechanical adjustment ground wheel assembly and hydraulically controlled profiling depth limiting ground wheel assembly were 62% and 82%,respectively,while the stubble-cutting depth criterion was(5.0 ± 10)mm,and the average quality rate of stubble-cutting depth of hydraulically controlled profiling depth limiting ground wheel assembly was 20 percentage points higher than that of mechanical adjustment ground wheel assembly.Nevertheless,when the stubble-cutting depth criterion was(50±5)mm,the corresponding stubble-cutting depth quality rate were 30%and 50%,respectively,and the average quality rate of stubble-cutting depth of hydraulically controlled profiling depth limiting ground wheel assembly was 20 percentage points higher than that of mechanical adjustment ground wheel assembly.The test results showed that the hydraulically controlled profiling depth limiting ground wheel assembly can greatly maintain stubble-cutting depth stability and ensure that the effect of clean straw was stable. |
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