Design And Testing Of A Crushed Soil Suppression Machine Based On Corn Strip-till Technology

Strip-till technology is one of the conservation tillage techniques,which is gradually accepted by the majority of farmers for its advantages of high operational efficiency,low cost and improved sowing quality.In strip-till technology,the soil is treated in advance,which can effectively improve the quality of sowing and create good conditions for crop growth.The former loosens the soil and enhances the permeability of the soil,which is conducive to crop growth;the latter compacts the soil to reduce the emission of soil moisture and temperature,providing a better growing environment for crops.However,there are still problems such as high power consumption and low operational efficiency of the land preparation agricultural machinery used for strip-till technology.In order to solve such problems,this paper designs a combined soil crushing and suppressing machine for the two aspects of pre-sowing corn under strip-tillage technology.The main accomplishments of this thesis are as follows:(1)Structural design of soil crushing parts and vibratory suppression device.Using Solidworks 3D design software to complete the 3D model design of the whole machine,determine the overall structure of the soil crushing and suppression device,and the main operating components for calculation and analysis,to get the rake diameter of 410 mm,thickness of 5mm,rake spacing of 125 mm ～ 150 mm,soil crushing parts spindle length of 980 mm.suppression device single counterweight maximum pressure range of 109.7N ～ 1132.7N.(2)Static analysis and finite element modal analysis of the vibratory ballast device.The maximum deformation of the drive shaft is 0.001 mm and the maximum principal stress is 1.769 MPa,and the maximum deformation of the vibratory ballast device is 0.192 mm and the maximum principal stress is 6.254 MPa.The materials of both the vibratory ballast device and the drive shaft are Q235 steel,and the maximum principal stress is less than the allowable stress.Therefore,the material strength meets the design requirements.The 3D model of the vibrating ballast device was imported into ANSYS modal analysis interface using Solidworks software,and the first six orders of vibration model and frequencies were calculated and analyzed.The analysis results show that the inherent frequencies are distributed in 35.435Hz～43.085 Hz and87.912Hz～87.916 Hz,which are widely spaced from the motor excitation frequency of50 Hz,and the comparative data analysis shows that the vibrating ballast device will not resonate.(3)Design of control system for vibratory ballast device.In this paper,the hardware circuit and software control program of the control system of vibratory ballast device were designed,and the control system was divided into three levels to realize the adjustment of the motor speed,so as to change the ballast pressure.A three-factor,three-level orthogonal test with mulch thickness,soil moisture content and ballast intensity as factors and corn seedling emergence rate as index was conducted in a corn breeder tank.The order of significance of the seedling emergence factors was obtained as follows: soil moisture content,suppression strength,and mulch thickness.The best seedling emergence rate was achieved at a mulch thickness of 4 cm,a suppression strength of 20 k Pa and a soil moisture content of 20%.In order to investigate the relationship between the suppression strength and soil moisture content,we designed the suppression strength-soil moisture content test based on the data obtained from the seedling test,and obtained that the soil moisture content varied little when the suppression strength was 20 k Pa,and the soil had better moisture storage capacity.And according to the test results,the soil moisture content of 20%was used as the basis for classification,and the first grade was determined as 18 k Pa,the second grade as 20 k Pa and the third grade as 22 k Pa.(4)Field test of soil crushing and suppressing machine tools.Soil crushing components to harrow blade spacing,plowing depth,the machine forward speed as a factor of the test,the machine harrow blade spacing,forward speed,plowing depth on the crushing rate of the significant impact of: forward speed,harrow blade spacing,plowing depth.For the whole machine,a three-factor,three-level test was designed with the forward speed,plowing depth and ballast strength of the implement as the test factors and soil firmness and soil flatness as the indexes,and the field test was conducted using Design Expert software.When the forward speed was 3km/h,the ballast strength was 21 k Pa,and the plowing depth was 8cm,the soil firmness was53.1k Pa and the soil flatness was 2.8cm,which were close to the predicted results,indicating that the soil crushing and ballasting machine worked best under the conditions.