| As one of the core technologies of conservation tillage,planting with less and no tillage can effectively reduce wind erosion and water erosion for soil,which is of great significance to the development of local economy,increase of farmers' income and protection of ecological environment.In no-till sowing operation,the winding and congested tillage parts such as crop stubble,straw and grass are the main influencing factors for the difficult passage of machinery and tools,the mixing of grass and soil,and the phenomenon of seed hanging rack.In this paper,the technical idea of combined operation of driving stubble cutting and passive grass guiding is put forward,and a combined device of grass and soil separating is designed to cut stubble and guide grass.The main research contents and conclusions are as follows:(1)The combined operation scheme of driving stubble cutting and passive grass guiding is adopted to realize anti-blocking,and the combined grass and soil separation device of stubble guiding is designed.A "W" shaped ditch was created by cutting,moving and throwing straw and grass with a concave notch disc cutter,and the stubble killing blade was used to pretill the seedling belt to a certain extent.With the advance of the unit,the furrow opener gradually breaks the stubble into the soil and creates a "V" shaped ditch.The straw guide board on the furrow opener leads the broken straw and grass into the "W" shaped ditch to realize the separation of grass and soil.On the basis of analyzing the law of interaction between straw guide board and straw and weeds,and combining with CFD simulation technology,the convex grass guide board with radius of 150 mm is determined to be the structure of the grass guide board.(2)Study on the mechanism of combined grass and soil separation device for cutting stubble and guiding grass.Concave gap is established when the disc cutter cutting broken straw and weeds of kinematics model,the results show that as the performance of the the grass soil separation device of main structure parameters are concave gap cutting disc buried depth H,turning radius R,rotational speed n,and the unit speed argument,knives,plate angle alpha,blade height H and concave gap cutting disc rotation center and the initial contact point of attachment of straw and shear slip Angle tau;Based on the analysis of straw and weed throwing trajectories,the maximum throwing distance of straw and weed in horizontal and vertical directions was determined.(3)To study the influence of structural parameters of the grass-soil separation device on the grass-soil separation effect.A discrete element simulation model of soil-straw interaction was established,and single factor and quadratic orthogonal rotation regression tests were carried out on the basis of straw clearance rate and soil disturbance in seedling belt.The results show that the bevel angle of the cutting disc,the depth of the cutting and the height of the cutting teeth of the concave notched disc cutter have significant effects on the operation effect of the grass-soil separation device.The optimum combination of the parameters was obtained: the depth of the cutting head was 73.63 mm,the height of the cutting teeth was 69.70 mm,and the Angle of the cutting head was 23.41°.(4)To study the field performance of the combined grass and soil separation device for cutting stubble and guiding grass.Field test results show that the straw and soil separation device has good passability and stable working performance,straw clearance rate and soil disturbance amount in seedling belt are 90.16% and 20.85% respectively,and the average sowing depth,fertilization depth and seed spacing are 60.4mm,120.2mm and 59.8mm,respectively.Meet the agronomic requirements of corn no-till sowing operation. |
PDF Full Text Request