Design And Experimental On Longitudinal Axial Conical Cylinder Threshing Unit Of Plot Wheat Seed

Aimed at long time spend and large indirect loss in manual harvesting of cropland plotbreeding, high rate of grains loss and broken in common threshing process, high degree of seedsmixture and seeds cleaning difficulty in stage harvesting method (It means: threshing withcommon wheat thresher firstly, and then after that cleaning with cleaner weapon) which causeddistortion of breeding test data, the longitudinal axial conical cylinder threshing unit wasresearched and developed. With cyclone air cleaning device, the unit could be applied tohalf-feeding cropland plot breeding wheat seeds combine harvester. In this paper, the followingaspects were studied and researched more deeply:（1）According to the cropland plot wheat breeding harvest requirements, the structurescheme we determined for the longitudinal axial conical cylinder threshing unit was as following:feed quantity selected0.3kg/s-0.5kg/s, rotate speed of cylinder was1500r/min-1600r/min. Basedon these operating parameters, the workability of the unit was preliminarily tested, and theexperimental results showed that the residual rate in internal shell was0.12%-0.33%, the totalloss rate was0.32%-0.43%, the broken rate was0.34%-0.72%, and the power consumption was1.76%-2.57%. This suggested that structural design was reasonable and it basically met thecropland plot wheat breeding harvest requirements, which was expected to completely solve theseeds residue problem in harvester by follow-up test.（2）The mechanical properties of the ears of plot breeding wheat was theoreticallyanalyzed, and the ears of breeding wheat in moisture content of17.4%and23.3%were testedunder tensile and compressive experiments in vertical and tilt position with the CMT2502electronic material testing machine, and the tension and compression test curve and strength ofbreeding wheat ears under different moisture content were obtained, which provided a referencefor the follow-up optimization of structure and motion parameters of threshing unit.（3）The parameters related to the working performance of conical cylinder threshing unit(such as contact mechanics properties in collision course between breeding wheat and threshingcomponents, the relations between breeding wheat damages and speed of threshing components)were analyzed theoretically, and the mathematical relationship between all these parameters wasobtained. Aimed at the threshing performance (such as the seed damage rate, the total loss rate,the seeds remaining rate, the power consumption, the cleaning impurity rate, the seeds brokenrate and germination situation etc), by changing structural parameters of important component(such as the cylinder taper angle, the type of threshing components and the way of ascension pipe installation), the comparative experiment was carried out on the test bench. The resultindicated that cylinder taper angle and threshing components were important structuralparameters which could affect the performance of threshing unit. After optimal parameters wereconfirmed, a kind of threshing unit combined with nail teeth and short-rasp-bar teeth wasdeveloped, and the cylinder taper angle of the threshing unit was13°. The field experiments ofthe threshing unit showed that the threshing loss rate was0.43%, trash content rate in separatedseeds was6.23%, seeds remaining rate was0%, power consumption was2.48kW, and theseperformance parameters fit the demand of cropland plot wheat seed harvester.（4）Relied on optimized and improved longitudinal axial conical cylinder threshing unit,according to working theory and method of cropland plot seed thresher and combine harvester, atest bench device was designed. Aimed at main factors (such as material feeding amount,rotating speed of cylinder, threshing device clearance, rotate speed of sucking fan, etc) whicheffect on total threshing loss rate (which include unthreshing loss rate and smuggle loss rate inthreshing process), trash content rate in separated seeds, seeds remaining rate in internal shelland broken rate in threshing process, the bench test was carried out adopting orthogonalexperiment. Finally the best operating parameters was obtained as following: the feed quantitywas0.3kg/s, the threshing device clearance was11mm, the rotate speed of sucking fan was1050r/min, the rotate speed of cylinder was1500r/min.