Development And Performance Test Of Three-stage Six-boom Swing Separation Sieve

The swing separating screen of potato excavator is the core structure of potato soil separation in mechanized potato harvesting,which has great influence on potato storage after harvest.Along with the separation process,there is no soil protection at the tail of the original separation screen,which causes serious potato damage.In order to solve the problems of high potato peel rate and serious potato damage in the process of potato-soil separation,the acceleration of screen surface was analyzed by theoretical analysis and virtual simulation,a kind of third-order six-suspender swing separation screen which can realize the step-by-step decrease of separation ability is designed.Its main research contents are as follows:(1)In order to reduce the damage of potato in the final stage of the potato soil separation process,based on the same requirements of the potato soil separation function and transportation function,the feasibility of realizing the function of the third-order sixsuspender structure is analyzed with the correlation theory.(2)The model of the third-order six-suspender separating screen is established and its movement is simulated.Through the simulation analysis,the structure parameters of the separating screen are improved continuously,so that the motion of the mechanism is noninterference and reaches the ideal motion state,the acceleration in the horizontal direction changes slightly,and the acceleration on the screen increases with the crank speed and the position of the connecting rod.The designed three-stage six-derrick swing separation screen drawing,processing,assembly,debugging,and will be replaced by the separation screen potato excavator,assembled into a new generation of potato excavator.(3)A single factor experiment was designed to study the effects of crank speed,machine forward speed and connecting rod length on the screen surface acceleration,the mixture height of potato and soil,the percentage of open tubers and the percentage of broken skin,respectively,the results show that with the increase of crank speed,the acceleration of screen surface becomes larger,the mixture height of potato and soil becomes lower,the rate of open potato first increases and then decreases,and the rate of skin breaking increases,the acceleration of sieve surface and the rate of potato and soil show a slight fluctuation,the mixture height of potato and soil becomes higher and the rate of broken skin decreases,and the mixture height of potato and soil first becomes higher and then lower with the change of the length combination of connecting rods,the rate of fresh tuber and the rate of broken skin were decreased.(4)Using SPSS to analyze the relativity of screen surface acceleration,potato-soil mixture height,potato rate and peel rate when different crank speed,machine advance speed and connecting rod length are combined.The results show that the first-order acceleration is negatively and significantly correlated with the potato-soil mixture height on the first-order sifter,and positively correlated with the skin-breaking rate.The mixture height of potato and soil was not significantly related to the rate of peeling.The height of potato-soil mixture was significantly correlated with the rate of skin breakage at different machine speeds.When the length of connecting rod is different,the first order screen surface acceleration is significantly related to the potato-soil mixture height.(5)The orthogonal experiment was designed to study the influence of crank speed,machine advance speed and boom length on the rate of open tuber and the rate of broken skin,and to obtain the best parameter combination of separating screen.The order of the influence on the rate of raw potato is: machine speed > connecting rod length combination >crank speed;the order of the influence on the rate of broken skin is: crank speed > connecting rod length combination > machine speed,the optimal scheme is crank speed 180R/min,connecting rod length combination 335-1050,machine forward speed 1.89 km/h.the test results show that the rate of fresh potato is 98.04%,and the rate of peeling is 1.58%.