| Aiming at the problem that the winter coleseed planting process in Jiangsu rice oil rotation area is prone to continuous rainfall,which causes high humidity in the field and difficult to operate.According to the related agronomic requirements of cole planting,a no-till cole planter suitable for this operating condition was designed,and its basic performance reached the design goal.However,there are some shortcomings:1.The selected core-shaft opener has problems of collapse and ditch bending during the operation,which is not conducive to the discharge of field water and is easy to cause cole damage;2.Designed The gear-tooth straw cleaning device has insufficient adaptability to high-humidity land.With the operation of the machine,it is easy to adhere to the soil and straw,causing the strips to be congested and resulting in a low seedling emergence rate.This article aims to improve the adaptability and work quality of the equipment to the high-humidity operating environment,and proposes an improved design for the above two problems.The main research contents are as follows:(1)Investigate and study the physical properties of soil and straw in high-humidity land.The results show that the average thickness of the plow bottom of the test plot is10.70 cm,the average soil bulk density is 1.09 g/m3,the maximum soil firmness of the0-20 cm soil layer is 1113 k Pa,the soil moisture content is as high as 77.98%,and the soil binding force is 15.30 k Pa.The porosity is 10.42%.The average stubble height is6.50 cm,the average length of straw after returning to the field is 6.30 cm,the number of straws is 763/m2,and the average moisture content is 64.31%.At the same time,the adaptability of the existing ditching and straw cleaning components in this area to highhumidity land was investigated,and the design requirements of the ditching and straw cleaning operation components in this environment were clarified.(2)The design analysis of the trenching components of the high-humidity land was carried out.Aiming at the problem that general ditching components are difficult to adapt to the working conditions of high-humidity land,a combined ditching component with a front ditching plowshare and a rear plastic opener is designed.The plow body surface of the ditching plowshare is designed using the horizontal straight element line method,and the maximum element line angle is determined to be 45 °,the minimum element line angle is 40 °,and the soil entry angle is 60 °;the arc cutting edge curve is selected as the shaping opening.For the cutting edge of the groover,it is determined that the initial sliding cutting angle is 18 °,the ending sliding cutting angle is 45 °,and the maximum cutting edge angle is 77.3 °.According to the empirical formula,the theoretical maximum rise of the soil on both sides of the trench during the trenching operation is 94 mm,the width of the soil on both sides of the trench is 53 mm,and the theoretical lift angle of the shaping wing is 7.6 °.Using ANSYS to check the strength of the plastic opener,the results show that the maximum load of the plastic opener is 14.291 MPa,the maximum deformation is at the junction of the cutting surface and the side wall,and the maximum deformation is 0.043 mm.(3)Carried out the design analysis of straw cleaning components in high-humidity land.Aiming at the problem of wet heavy straw accumulation in the field and difficulty in seeding,a straw cleaning component combining active and passive is designed.Through the analysis of the movement force of the active soil and straw separating knife when separating the straw,it is determined that the radius of gyration of the tool is 138 mm,the rotation direction of the tool is reverse rotation,the speed range of the tool is62～155 r/min,and the soil cutting pitch is 60 mm,the number of tools is 3.Through the analysis of the stress on the straw during the operation of the seed belt and the agronomic requirements of cole sowing,it is determined that the opening angle of the straw guide plate is 60 °.And based on the EDEM simulation technology,the straw cleaning rate ε is used as the test index,and the three-factor three-level orthogonal test is designed.The test results are analyzed by response surface and the parameters are optimized.The best combination of parameters is obtained as: cutter shaft speed n =147r/min,machine forward speed v=2.5 km/h,and the number of straw per unit area is 510.At this time,the straw removal effect is the best,and the straw removal rate is:ε=82.30%.(4)The field test of the ditching component and the straw cleaning component of the coleseed direct seeding machine in high-humidity land was carried out,and the operation quality was evaluated.During the experiment,the field soil moisture content was 80.33%,the straw moisture content was 63.5%,and the average straw length was6.50 cm.The test results show that the ditching stability coefficient of the machine exceeds 87%,and the ditch type is complete,which meets the agronomic requirements of ditching operations in cole sowing;the best parameter combination obtained in the simulation test is used as the test condition,and the test distance is 20 m.The verification test of straw removal rate was conducted at five randomly selected points.The average straw removal rate was 80.88%,which was greater than the design requirement of 75%.The straw removal rate was in line with the agronomic requirements for cole planting. |
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