| Mechanized recovery of residual film is the development trend of residual film recovery after autumn.It can effectively improve the working efficiency and reduce labor intensity and operation cost of residual film recovery in autumn cotton field in Xinjiang.At present,the residual film recovery rate is low and the impurity rate is high.In this paper,based on the analysis of the existing research results,based on the characteristics of residual film materials after autumn,through theoretical analysis,simulation and experimental research,a kind of cotton stalk chopping and returning to the field in one time was developed.The parameters of the machine meet the agronomic requirements and the research results are helpful to solve the problem of residual film pollution in Xinjiang cotton area.The main findings include:(1)By testing and analyzing the physical characteristics of the residual film after the autumn of that year,it is concluded that compared with the physical characteristics of the new mulch film,the physical characteristics of the residual film such as transverse and longitudinal tensile load and fracture elongation have obviously changed.With the increase of laying time,the physical characteristics of plastic film decreased significantly.The suspension characteristics of the residual membrane showed that there was no correlation between the surface area of the residual membrane and the suspension velocity,but there was a correlation between the mass of the residual membrane and the suspension velocity.(2)The dynamic and kinematic analysis of the cotton stalk comminution transport returning device was carried out.The crushing mode of cotton stalk supported by moving fixed knife was determined.The Y-type blade with the blade density of 0.26/cm and the number of 56 blades was selected for the moving blade.The linear velocity of the end point of the moving knife is 52.35～52.90m/s,which can meet the need of agriculture more than 48m/s.The screw conveyer with a spiral outer diameter of 400 mm,and a pitch of 120 mm,and a theoretical conveying capacity of 2.81kg/s was adopted.(3)In order to adapt to different types of field environment,two kinds of film-lifting components with different structures,shovel-type and tooth-type,were developed,and the structural parameters and operating parameters of two kinds of film-lifting components were determined.According to the existing research results,a new type of eccentric roller-type residual film pick-up mechanism is designed through the method of optimal transmission of the double crank model with unequal edges.The length of the telescopic rod tooth is 210 mm,and the installation angle of the telescopic rod tooth is 45 °.The number of mounting pedestal in circle is 6,the diameter of mounting disk is 190 mm,and the rotational speed of telescopic gear assembly is greater than that of 97r/min and other structural parameters and operating parameters.(4)A soil-residual film composite finite element model was established.The deformation and stress of the soil-residual film composite finite element model were analyzed by using nonlinear finite element method.It is concluded that when the residual membrane is punctured at the end of the operation,the remaining part of the residual film will not be damaged.The finite element model of the telescopic rod tooth assembly is established,the vibration characteristics are analyzed,the first six modal modes of the telescopic rod tooth assembly are analyzed,the structural optimization is carried out for the weak link,and the stability of the structure is improved after the structural improvement.The operating environment frequency of the telescopic rod-tooth assembly is 0.62 Hz,which is far less than the calculated modal distribution,and the structure is safe and stable.(5)Taking the feeding angle,depth,advance speed and rotating speed of the pick-up roller as the test factors,the recovery rate of the residual film and the impurity rate of the recovered residual film were taken as the test indexes.The performance tests of the structure parameters and the working parameters of the tooth-type residual film picking-up device and the shovel-type residual film picking-up device are carried out respectively.The results of field experiment show that the optimum value of the test index is when the angle of tooth entering into soil is 30°and the depth of entering soil is 40 mm,the advance speed of the machine is 6km/h in the tooth-type residual film picking-up device.In the scraper-type residual film picking-up device,when the film-lifting shovel is put into the earth angle 30°,the pick-up roller speed is 120r/min,and the forward speed of the machine is 3.6km/h,the test index has the optimal value.(6)The three-dimensional numerical simulation of the flow field characteristics in the shell of the film-releasing device is carried out,and the effects of the structural parameters and the operating parameters on the performance of the film-releasing device are analyzed.The optimum design parameters are the blade number of the release roller is 6,and the rotational speed is 1000r/min.The experimental results show that the actual outlet wind speed of the film unloader is 7.40m/s,and the error rate of between the simulation and the simulated 7.94m/s is 6.8%,which verifies the accuracy of the simulation analysis.(7)A prototype of the corresponding residual film recovery machine for autumn has been made.The field experiment shows that the average qualified rate of stubble height,crushing length and residual film recovery rate of toothed operating machine is 92.3%,91.8% and 84.4%,respectively.The impurity content of residual membrane was 12.7;he average qualified rate of stubble height,crushing length and residual film recovery rate of toothed operating machine is 93.9%,90.1% and 89.1%,respectively.The impurity content of residual membrane was 5.4%,and the winding rate was less than 2%.According to the requirements of GB/T25412-2010(residual plastic Film Recycling Machine)and GB/T24675.6-2009(Conservation Tillage Machinery: straw crushing and returning Machine),the main performance indexes of the test prototype can meet the requirements of field agronomy. |
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