| Cleaning is an important part of the potato harvesting process,and the quality of potato cleaning will affect the subsequent transportation and storage effect.For the existing potato combine harvester cleaning device to remove the low rate of debris,injury rate,and high rate of broken skin,this paper based on 4UL-170 D bagging potato combine harvester,designed a cleaning device with an alternate arrangement of cleaning roller and light roller,the main research content is as follows.(1)The basic characteristics of potatoes and soil physical properties during the harvest period were measured,and the geometric characteristics,density,and moisture content of Xisen 3 potatoes during the harvest period were determined,and the compression and friction characteristics of potatoes were measured using an electronic universal testing machine;at the same time,the moisture content,soil capacity and soil firmness of soil during the harvest period were measured to provide a theoretical basis for the design of the scavenging device.(2)The 4UL-170 D bagging potato combine is used as the basis for the structural design of the cleaning.The device adopts the alternate arrangement of cleaning rollers and light rollers,and the two rollers rotate at a differential speed for cleaning,which improves the cleaning effect of the potato harvest.The total length of the scavenging rolls is 1520 mm and the total length of the scavenging sleeve installation is 1190 mm.the design and contact point mechanical analysis of the scavenging sleeve determines that the material of the scavenging sleeve is rubber,the radius of the outer edge is 70 mm,the pitch is 340 mm,the height of the spiral fan blade is 10 mm,the spiral lift angle is 55° and the height of the scavenging sleeve is170 mm.The material of the light rollers is alloy steel,the radius is 30 mm,the overall length is 1520 mm and the length of the central round rollers is 1190 mm.The optimum number of cleaning rollers is determined by single-factor tests as 5 groups.(3)The potato cleaning process is characterised by the feeding process,the movement of the potatoes on the roller set and the soil separation conditions,the angle of inclination of the separating sieve is 25° and the height difference between the separating sieve and the cleaning device is 260 mm.The main factors affecting the potato cleaning effect are the feeding volume,the inclination of the device,the speed of the cleaning roller,the speed of the light roller,the distance between the cleaning roller and the light roller,and the relative height of the cleaning roller and light roller.(4)Single-factor test and orthogonal test were conducted with feeding volume,the tilting angle of the device,cleaning roller speed,light roller speed,roller distance between cleaning roller and light roller,and relative height of cleaning roller and light roller as test factors,and wounding rate,peel breaking rate and trash removal rate as test indexes.An optimization model of the parameters of the cleaning device was established,and the optimal combination of parameters was obtained: loading capacity of 4.3 kg/s,the inclination angle of the device of10.3°,speed of the cleaning roller of 119 r/min,speed of the light roller of 148 r/min,roller distance of the cleaning roller and light roller of 16.8 mm,the relative height of the two rolls of40.5 mm,corresponding to the injury rate of 1.06%,skin breaking rate of 0.54%,and trash removal rate of 96.15%.Field verification tests were conducted on the optimal combination of parameters,and the test results were 1.10% injury rate,0.55% skin breakage rate,and 95.04%trash removal rate,with the relative error between each index and the predicted value of the model less than 5%,meeting the overall operation quality requirements of the 4UL-170 D bagging potato combine harvester. |
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