Design And Experiment Of Key Parts For A No-till Seeder For Rapeseed With An Middle Furrowing Device

In view of the fact that the traditional trenching device has a larger structure and higher power consumption,and poor soil throwing performance,which cannot meet the requirements of oilseed rapeseed planting,the key components of the intermediate trenching rapeseed no-till planter are designed in combination with the concept of conservation tillage and the light,such as furrowing,tilling,seeding,mulching and fertilizing at one time.The major research elements and inferences are set out below:（1）General process solution for a no-till seeder for rapeseed with a middle furrowing is proposed.Comparing the operational characteristics of the no-till method and the traditional rotary tillage method,as well as the fact that the traditional trenching device cannot meet the needs of rapeseed planting,a no-till seeder for rapeseed with a middle furrowing and soil leveling on both sides is proposed.The overall structure of the no-till seeder for rapeseed is determined.The machine consists of a frame,a central gearbox,an intermediate furrow-opening component,a shallow,rotating screeding component,a furrow-clearing and shaping component,a soil-dragging component,a seed-discharge system and a fertilizer-discharge system,which can realize the multi-step operation processes of furrow-opening,tillage,seeding,mulching,and fertilizer application.The analysis clarifies the main technical parameters of the machine:the machine has a working width of 2000 mm,an operating speed of 4～8 km.h^-1,a trapezoidal furrow with a depth of 150～200 mm and a width of 250～320 mm,and a half compartment with a length of 800 mm on both sides of the furrow;the machine passes in reverse for the second time,and the edges of the compartments of the two operations are joined to form a complete compartment with a width of 1600 mm.（2）The structure and parameters of the key parts for a no-till seeder for rapeseed with a middle furrowing device are designed and analyzed.Including:（1）The radius of gyration of the furrow opening blade is 320mm.Based on the principle of slip-cutting and drag reduction,the edge curve of the furrow opening blade adopts the Archimedes helix.By establishing the kinematic model of the soil-throwing process of the furrow opening blade,the analysis determines that the distance of soil throwing is related to the shape of the positive cutting edge of the furrow opening blade and the bending angle of the furrow opening blade,etc.The farthest throwing distance is calculated to be0.45m.（2）The plow is mainly composed of two parts:the breaking surface and the shaping surface;to ensure that the plow acts with an equal thrust forward as well as pressure to both sides,the design edge angle is 90?.,through an analysis of squeezing mechanics,the maximum lateral inclination angle of the shaping surface has been determined to be 67?,the length of the shaping surface is 470 mm according to the analysis of the soil particle flow back process.（3）The eccentric arc is used as the edge curve of the shallow rotary cutter.When the eccentric distance e is 135mm,and the radius of the eccentric arc is 182mm,the sliding angle of the shallow rotary cutter is42?,which meets the requirements of the shallow rotary cutter for stubble removal.The thickness of the elliptical shallow,rotating blade is 10mm;the static and kinematic analysis of the soil particles during the operation of the spiral screed has determined the radius of the spiral to be 80～100mm and the pitch range to be 120～547mm.（3）Simulation tests and research are carried out on the key parts for a no-till seeder for rapeseed with a middle furrowing device based on the discrete element software EDEM.Including:（1）According to the results of the tests,the optimal structural parameters for achieving the best soil throwing uniformity were determined to be:a depth of 200mm,a rotational speed of 360r/min,and a running speed of 6km/h.In addition,a bend angle of 70?for the vertical rotary cutter and a blade width of 60mm were found to be the most effective.At these structure parameters,the soil throwing uniformity was measured at 91.24%.（2）One-factor tests were carried out on the influence in structure parameters such as spiral radius,pitch,and the number of spiral heads of the spiral screed blade on compartment surface flatness and straw burial rate.The test results show that:when other factors are certain,the compartment surface flatness decreases with the increase of the spiral radius of the spiral screed blade,and the straw covering rate increases with the increase of the spiral radius of the spiral screed blade,with the increasing pitch the compartment surface flatness decreases first and then increases,and the straw covering rate increases first and then decreases in the range of 250～450mm;when the pitch and spiral radius is certain,with the increase of the number of spiral heads,the compartment surface flatness shows an increase of 91%.When the pitch and spiral radius is certain,with the increase in the number of spiral heads,the flatness of the compartment surface tends to increase,and the straw cover rate decreases slightly.（3）Based on the range of parameters determined by the single-factor test analysis,orthogonal tests were conducted,a quadratic polynomial regression model was constructed with the compartment flatness as the evaluation index,and the test factors affecting the compartment flatness were analyzed,and the influencing factors in order were:pitch,spiral radius and a number of spiral heads.With these structural parameters,the flatness of the compartment surface is 12.69 mm.（4）Field trials and research on the key parts of a no-till seeder for rapeseed with a middle furrowing device were carried out.The main components are:（1）The mechanical and physical characteristics parameters of both soil and straw were assessed across four distinct working conditions selected from test plots 1,2,3 and 4 at the demonstration base of rice-rapeseed rotation mechanized production of Huazhong Agricultural University in Jianli of Hubei Province.The parameters measured in the field were:average soil firmness of 1837～2248 k Pa,average soil bulk weight of1.09～1.26 g/cm³,average stubble height of 185～249 mm,average surface straw volume of 631～1024 g/m² and average soil moisture content of 30.41～38.15%.（2）In the functional test carried out in test field No.1,the average furrow depth formed by the middle open bed furrow rapeseed no-till planter after the operation was 212.8mm,the average upper width of the furrows was 328.2mm and the average lower width264.8mm,with the stability factor of greater than 85%for depth and width of furrow,all the indicators after the operation met the requirements of GB/T 5668-2017"Rotary tiller"and NY/T 499-2013"Rotary tiller operation quality"standards.（3）Field operation quality tests under different working conditions were carried out in test plots No.1,No.2,and No.3,and the test results showed that:under the working conditions of high stubble height and large straw retention,the operating indexes such as compartment surface flatness,stubble burial rate and stability of furrow depth and furrow width would be worse;increasing the operating speed would reduce compartment surface flatness and stubble burial rate;increasing the rotational speed of the cutter would improve compartment surface flatness.（4）Sowing test was carried out in the No.4working condition test field.The machine was equipped with a mechanical centrifugal seeder and a double disc furrow opener,the number of rows sown was 6,and the rapeseed variety sown was Chinese rapeseed 62.