Design And Experiment Of Sliding-Knife Notched Disc Opener

Implementation of conservation tillage in the Northeast black siol area is necessary tothe stable development of agriculture and to the long-term effective supply of agriculturepruducts, as well as to avoid wastage of resources. Improper farming mode is the mainreason for the loss of resources of the black soil area. The core of conservation tillage isno-tillage and minimum tillage, so the primary task of the implementation of conservationtillage is supporting the development of no-tillage planter. The planter designed domestic hassmall structure, light weight, and most are not equipped with independent broken stubbleinstitutions. Besides, as the coverage caused by a lot of straw, the opener can not cut off thestalks. In addition, cut the soil for fertilization and seeding can cause the blockage of theseeder, which can not work normally. Therefore, the design of a fertilizer opener has goodcut stubble capacity is the focus of the development of no-tillage planter.This article designed a sliding knife notched disc opener for the no-tillage conditions.Through stress analysis of the disc knife we got the condition that to make the straw beingcut off without being pushed to go, the disc cutter diameter shall be not less than420mm.Analyzing the changes of the blade cutting arc length in the working course of the disc cutter,we got the maximum cutting arc length being0.1m, and we used this data as a basis todesign the disc gap number of13. We analyzed the cutting performance of the slidingknife-edge as well as the stress distribution conditions in the process of cutting. The disccutting edge was composed of two parts, which was the sliding knife-edge and the arc-edge.The blade curve equation is as following: Arc edge equation is y=-0.1489x²+4.164x-22.552,13.18≤x≤19.4, the unit is mm；Sliding knife-edge equation is y=4E-05x⁶-0.0014x⁵+0.0188x⁴-0.1042x³+0.2669x²-0.0864x+0.0072，0≤x≤13.18，the unit ismm。 The groove-shaped cross section model of the single-disc opener was establishedusing the knowledge of the3D coordinate transformation in the three-dimensional space,which was cos²α₀（2hsinα0cosγ0-b）²＋4sin²γ₀（h－R）＝4cos²α₀sinγ₀R². The relationship within the working radius R、working declination α0、working inclination γ0、 groove depthh and groove width b of the groove-shaped corss section was established. The workingdeclination α0and inclination γ0of the notched disc cutter was determined as α0=6°, γ0=10°.We designed the fertilization arm、fertilization adjust library、protecting groove knife and thespring arm to complete the overall design of the notched disc opener.The simulation analysis of the cutting soil process by the notched disc knife wasconducted using the display dynamic analysis module of the ANSYS/LS_DYNA. Thethree-dimensional stess distribution of the ditched model was obtained, and the stessconcentration points in three directions of the ditched disc knife were not found, whichsuggested that the design of the blade parameters was rational. The three direction maximumstress and the maximum deformance occurred in the soil model. The maximum stress of theX-direction was334.8N and the maximum deformance was42.01mm; the maixmum stressof the Y-direction was467N, and the maximum deformance was65.89mm; the maixmumstress of the Z-direction was454.2N, and the maximum deformance was57.74mm.According to the analysis of the three direction variables, we obtained that the groove depthh of the simulation model was97.7mm-98.7mm, and the groove width b was68mm.Used the notched disc opener instead of the hole shovel opener to conduct the no-tillnarrow row two trial of the planter and the field trials. The results showed that the notcheddisc opener had good capacity to cut straw stubble and good buried performance, whichgreatly enhanced the machine through ability. Through the two-factor test on the operatingparameters of the notched disc knife, we got the optimum operating parameters, with theworking declination α0=6°, the working inclination γ0=10°.Through the performance test of the improved no-till narrow-row planter, we got theresults that the pass rate of the seed spacing was91%（≥75%）, the replay rate was10.5%（≤20%）, and the leak seeding rate was1.79%（≤10%）. All the planting performanceindicators met the requirements of the relevant national standards. The fertiliazation depth and the sowing depth of the no-till narrow-row planter both met the standard and werestable, with the average distance of the seed and the fertilizer being3.27cm, which met theoperational requirements. The displacement instability coefficient of variation of each lineand the inconsistency coefficent of variation of each line was11.9%and0.82%respectively,which all met the required standard.The research work conducted in this article has certain reference value on the furtherstudy of the no-tillage planter and on the simulation analysis of the soil deformation in theditching process, as well as on the establishment of the groove shaped cross-section modelof the opener.