Design And Experiment Of Subsoiler-stubble Chopper Device In No-tillage

In recently years,Traditional tillage mode has caused the decrease of soil organic matter.To avoid this problem,no-tillage tillage becomes more and more popular.The operation requirement of no-tillage tillage mode also becomes higher and higher.In order to solve these problems,such as large soil disturbance,large tillage resistance and large residual clod during subsoiling operation,a subsoiler-stubble chopper was designed in this paper.There were also some comparative tests,not only for the subsoiler,but also for the stubble chopper to verify their own superiority.The optimization test has also been done to get the most optimized device parameters.The paper studies on the subsoiler-stubble chopper through a series of processes,for example,experiment,theoretical analysis and verification to find out how to solve the problems exist on Northeast cornrow area under no-tillage tillage.The main research is as following:(1)The fitting curve subsoiler is designed: The paper uses the discrete element software to simulate the movement of the subsoiler tip in the soil.Through calculating,the fitting curve and fitting equation of the trajectory of soil particles above the tip of shovel can be obtained.Then using line element design to optimize the alignment to acquire the curve of shovel handle shape and design the edge.The angles of cutting lip and penetration can also be made sure at the same time.The cutting lip angle is 40° and the penetration angle is 21°.Then through the interaction effect test between shovel handle and shovel tip to prove the feasibility and rationality of the design.Finally,the fitting curve subsoiler is obtained.(2)The stubble chopper is designed: According to the field test and the kinematics analysis for the interaction effect among every device part,the range of the included angle between the blade curve and the ground is sure to be 10°-70°,the minimum radius of the stubble chopper is180 mm,the middle radius is 215 mm,the maximum radius is 235 mm,the minimum distance between subsoiler and stubble chopper is 20 mm.The design is verified to be reasonable by discrete element simulation experiment.(3)The soil bin contrast test and the field contrast test show the operating performance of the fitting curve subsoiler.The soil bin contrast test shows that compared to polygonal subsoiler,the fitting curve subsoiler makes the soil disturbance reduced by 53.6%,tillage resistance reduced by 36.23%.Compared to circular subsoiler,the fitting curve subsoiler makes the soil disturbance reduced by 66.18% and the tillage resistance reduced by 29.18%.Field contrast test shows the backfill soil area made by the fitting curve subsoiler is 7745.4 mm2,made by the polygonalsubsoiler is 4278.6 mm2,made by the circular subsoiler is 3136.4 mm2.Both of the soil bin contrast test and the field contrast test verify that the fitting curve subsoiler can make the soil disturbance and tillage resistance smaller.It meets the requirements of conservation tillage.(4)Contrast test of discrete element simulation and field contrast test show the operating performance of the stubble chopper which has the interaction effect with the fitting curve.The contrast test of discrete element simulation shows that compared with subsoiler-stubble chopper,cutting dise and stubble chopper with breach,the subsoiler-stubble chopper with interaction effect can decrease the resistance.The decreased rates of cutting resisrance are 25.1%,16% and 31.5%;the decreased rates of device resistance are 8.3%,4.5% and 14.9%;but the effect of crushing soil increases.The increased rates are 11.5%,98.5% and 157%.The field performance test indicates that compare the interactional device with reference indicator,the stubble ratio increases by10.92%,the rate of crushing soil increases by 6.04%,and the oil consumption decreases by31.39%.The field contrast test shows that under the same operating condition,compare the subsoiler-stubble chopper with interaction effect to subsoiler-stubble chopper,cutting dise and the stubble chopper with breach,the average stubble ratio increases respectively by 3.53%,19.38%and 8.86%;under different working conditions,compared with subsoiler-cutting dise,when the average load decreases by 20 kg,the stubble ratio increases by 13.8%,the oil consumption decreased by 7%.when the average load decreases by 40 kg,the stubble ratio increases by 5.82%,the oil consumption decreased by 21.28%;compared with the stubble chopper with breach,when the average load decreases by 20 kg,the stubble ratio increases by 4.5%,the oil consumption decreased by 12.79%.(5)The discrete element simulation test and the field test are used to optimize the operating parameters of the device.The discrete element simulation test shows the primary and secondary factors that influence the power consumption are operating speed,subsoiling depth,device load and the distance between the subsoiler and stubble chopper;the primary and secondary factors that influence the compressive force on the stubble are device load,subsoiling depth,operating speed and the distance between stubble chopper and subsoiler.When the device load is 106.75 kg,the operating speed is 0.43 m/s,the subsoiling depth is 266.45 mm,the distance between stubble chopper and subsoiler is 332.12 mm,the power consumption is 0.6072 kw,the decrement of the compressice force is 411.506 N.It is the best operating performance.The field test finds out that compared with the traditional machine,the optimized device of subsoiler-stubble chopper makes the depth stability of subsoiling increased by 14%,the cutting stubble ratio increased by 15.05%,the rate of soil pulverization increase by 6.17%,the power consumption decrease by 48.6%,the oil consumption decreased by 13.8%.It proves that the optimized device has a better performance and it satisfies the requests of conservation tillage.The device designed in this paper can make use of the interaction effect between the subsoiler and stubble chopper to enhance the operating performance and operating effect of the whole device,which can provide some useful ideas for the design of some agricultural machinery and tools.